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Hewitt TC, Henningsen EC, Pereira D, McElroy K, Nazareno ES, Dugyala S, Nguyen-Phuc H, Li F, Miller ME, Visser B, Pretorius ZA, Boshoff WHP, Sperschneider J, Stukenbrock EH, Kianian SF, Dodds PN, Figueroa M. Genome-Enabled Analysis of Population Dynamics and Virulence-Associated Loci in the Oat Crown Rust Fungus Puccinia coronata f. sp. avenae. Mol Plant Microbe Interact 2024; 37:290-303. [PMID: 37955552 DOI: 10.1094/mpmi-09-23-0126-fi] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2023]
Abstract
Puccinia coronata f. sp. avenae (Pca) is an important fungal pathogen causing crown rust that impacts oat production worldwide. Genetic resistance for crop protection against Pca is often overcome by the rapid virulence evolution of the pathogen. This study investigated the factors shaping adaptive evolution of Pca using pathogen populations from distinct geographic regions within the United States and South Africa. Phenotypic and genome-wide sequencing data of these diverse Pca collections, including 217 isolates, uncovered phylogenetic relationships and established distinct genetic composition between populations from northern and southern regions from the United States and South Africa. The population dynamics of Pca involve a bidirectional movement of inoculum between northern and southern regions of the United States and contributions from clonality and sexuality. The population from South Africa is solely clonal. A genome-wide association study (GWAS) employing a haplotype-resolved Pca reference genome was used to define 11 virulence-associated loci corresponding to 25 oat differential lines. These regions were screened to determine candidate Avr effector genes. Overall, the GWAS results allowed us to identify the underlying genetic factors controlling pathogen recognition in an oat differential set used in the United States to assign pathogen races (pathotypes). Key GWAS findings support complex genetic interactions in several oat lines, suggesting allelism among resistance genes or redundancy of genes included in the differential set, multiple resistance genes recognizing genetically linked Avr effector genes, or potentially epistatic relationships. A careful evaluation of the composition of the oat differential set accompanied by the development or implementation of molecular markers is recommended. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Tim C Hewitt
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Canberra, ACT 2600, Australia
| | - Eva C Henningsen
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Canberra, ACT 2600, Australia
| | - Danilo Pereira
- Christian Albrechts University of Kiel, 24118 Kiel, Germany
- Max Planck Institute of Evolutionary Biology, 24306 Plön, Germany
| | - Kerensa McElroy
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Canberra, ACT 2600, Australia
| | - Eric S Nazareno
- Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, U.S.A
| | - Sheshanka Dugyala
- Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, U.S.A
| | - Hoa Nguyen-Phuc
- Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, U.S.A
| | - Feng Li
- Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, U.S.A
| | - Marisa E Miller
- Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, U.S.A
| | - Botma Visser
- Department of Plant Sciences, University of the Free State, Bloemfontein 9300, South Africa
| | - Zacharias A Pretorius
- Department of Plant Sciences, University of the Free State, Bloemfontein 9300, South Africa
| | - Willem H P Boshoff
- Department of Plant Sciences, University of the Free State, Bloemfontein 9300, South Africa
| | - Jana Sperschneider
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Canberra, ACT 2600, Australia
| | - Eva H Stukenbrock
- Christian Albrechts University of Kiel, 24118 Kiel, Germany
- Max Planck Institute of Evolutionary Biology, 24306 Plön, Germany
| | - Shahryar F Kianian
- Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, U.S.A
- USDA-ARS Cereal Disease Laboratory, St. Paul, MN 55108, U.S.A
| | - Peter N Dodds
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Canberra, ACT 2600, Australia
| | - Melania Figueroa
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Canberra, ACT 2600, Australia
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Nazareno ES, Fiedler JD, Ardayfio NK, Miller ME, Figueroa M, Kianian SF. Genetic Analysis and Physical Mapping of Oat Adult Plant Resistance Loci Against Puccinia coronata f. sp. avenae. Phytopathology 2023; 113:1307-1316. [PMID: 36721375 DOI: 10.1094/phyto-10-22-0395-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Six quantitative trait loci (QTLs) for adult plant resistance against oat crown rust (Puccinia coronata f. sp. avenae) were identified from mapping three recombinant inbred populations. Using genotyping-by-sequencing with markers called against the OT3098 v1 reference genome, the QTLs were mapped on six different chromosomes: Chr1D, Chr4D, Chr5A, Chr5D, Chr7A, and Chr7C. Composite interval mapping with marker cofactor selection showed that the phenotypic variance explained by all identified QTLs for coefficient of infection range from 12.2 to 46.9%, whereas heritability estimates ranged from 0.11 to 0.38. The significant regions were narrowed down to intervals of 3.9 to 25 cM, equivalent to physical distances of 11 to 133 Mb. At least two flanking single-nucleotide polymorphism markers were identified within 10 cM of each QTL that could be used in marker-assisted introgression, pyramiding, and selection. The additive effects of the QTLs in each population were determined using single-nucleotide polymorphism haplotype data, which showed a significantly lower coefficient of infection in lines homozygous for the resistant alleles. Analysis of pairwise linkage disequilibrium also revealed high correlation of markers and presence of linkage blocks in the significant regions. To further facilitate marker-assisted breeding, polymerase chain reaction allelic competitive extension (PACE) markers for the adult plant resistance loci were developed. Putative candidate genes were also identified in each of the significant regions, which include resistance gene analogs that encode for kinases, ligases, and predicted receptors of avirulence proteins from pathogens.
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Affiliation(s)
- Eric S Nazareno
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, U.S.A
| | - Jason D Fiedler
- U.S. Department of Agriculture-Agricultural Research Service, Cereal Crops Research Unit, Fargo, ND, U.S.A
| | - Naa Korkoi Ardayfio
- U.S. Department of Agriculture-Agricultural Research Service, Cereal Crops Research Unit, Fargo, ND, U.S.A
| | - Marisa E Miller
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, U.S.A
- Pairwise Plants, LLC, 807 East Main Street, Suite 4-100, Durham, NC, U.S.A
| | - Melania Figueroa
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Canberra, ACT, Australia
| | - Shahryar F Kianian
- U.S. Department of Agriculture-Agricultural Research Service, Cereal Disease Laboratory, St. Paul, MN, U.S.A
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Nazareno ES, Fiedler J, Miller ME, Figueroa M, Kianian SF. A reference-anchored oat linkage map reveals quantitative trait loci conferring adult plant resistance to crown rust (Puccinia coronata f. sp. avenae). Theor Appl Genet 2022; 135:3307-3321. [PMID: 36029319 DOI: 10.1007/s00122-022-04128-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 05/13/2022] [Indexed: 06/15/2023]
Abstract
We mapped three adult plant resistance (APR) loci on oat chromosomes 4D and 6C and developed flanking KASP/PACE markers for marker-assisted selection and gene pyramiding. Using sequence orthology search and the available oat genomic and transcriptomic data, we surveyed these genomic regions for genes that may control disease resistance. Sources of durable disease resistance are needed to minimize yield losses in cultivated oat caused by crown rust (Puccinia coronata f. sp. avenae). In this study, we developed five oat recombinant inbred line mapping populations to identify sources of adult plant resistance from crosses between five APR donors and Otana, a susceptible variety. The preliminary bulk segregant mapping based on allele frequencies showed two regions in linkage group Mrg21 (Chr4D) that are associated with the APR phenotype in all five populations. Six markers from these regions in Chr4D were converted to high-throughput allele specific PCR assays and were used to genotype all individuals in each population. Simple interval mapping showed two peaks in Chr4D, named QPc.APR-4D.1 and QPc.APR-4D.2, which were detected in the OtanaA/CI4706-2 and OtanaA/CI9416-2 and in the Otana/PI189733, OtanaD/PI260616, and OtanaA/CI8000-4 populations, respectively. These results were validated by mapping two entire populations, Otana/PI189733 and OtanaA/CI9416, genotyped using Illumina HiSeq, in which polymorphisms were called against the OT3098 oat reference genome. Composite interval mapping results confirmed the presence of the two quantitative trait loci (QTL) located on oat chromosome 4D and an additional QTL with a smaller effect located on chromosome 6C. This mapping approach also narrowed down the physical intervals to between 5 and 19 Mb, and indicated that QPc.APR-4D.1, QPc.APR-4D.2, and QPc.APR-6C explained 43.4%, 38.5%, and 21.5% of the phenotypic variation, respectively. In a survey of the gene content of each QTL, several clusters of disease resistance genes that may contribute to APR were found. The allele specific PCR markers developed for these QTL regions would be beneficial for marker-assisted breeding, gene pyramiding, and future cloning of resistance genes from oat.
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Affiliation(s)
- Eric S Nazareno
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, USA
| | - Jason Fiedler
- US Department of Agriculture-Agricultural Research Service, Cereal Crops Research Unit, Fargo, ND, USA
| | - Marisa E Miller
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, USA
- Pairwise Plants, LLC. 807 East Main Street, Suite 4-100, Durham, NC, USA
| | - Melania Figueroa
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Canberra, ACT, Australia
| | - Shahryar F Kianian
- US Department of Agriculture-Agricultural Research Service, Cereal Disease Laboratory, St. Paul, MN, USA.
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Henningsen EC, Omidvar V, Della Coletta R, Michno JM, Gilbert E, Li F, Miller ME, Myers CL, Gordon SP, Vogel JP, Steffenson BJ, Kianian SF, Hirsch CD, Figueroa M. Identification of Candidate Susceptibility Genes to Puccinia graminis f. sp. tritici in Wheat. Front Plant Sci 2021; 12:657796. [PMID: 33968112 PMCID: PMC8097158 DOI: 10.3389/fpls.2021.657796] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 03/22/2021] [Indexed: 05/30/2023]
Abstract
Wheat stem rust disease caused by Puccinia graminis f. sp. tritici (Pgt) is a global threat to wheat production. Fast evolving populations of Pgt limit the efficacy of plant genetic resistance and constrain disease management strategies. Understanding molecular mechanisms that lead to rust infection and disease susceptibility could deliver novel strategies to deploy crop resistance through genetic loss of disease susceptibility. We used comparative transcriptome-based and orthology-guided approaches to characterize gene expression changes associated with Pgt infection in susceptible and resistant Triticum aestivum genotypes as well as the non-host Brachypodium distachyon. We targeted our analysis to genes with differential expression in T. aestivum and genes suppressed or not affected in B. distachyon and report several processes potentially linked to susceptibility to Pgt, such as cell death suppression and impairment of photosynthesis. We complemented our approach with a gene co-expression network analysis to identify wheat targets to deliver resistance to Pgt through removal or modification of putative susceptibility genes.
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Affiliation(s)
- Eva C. Henningsen
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, United States
| | - Vahid Omidvar
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, United States
| | - Rafael Della Coletta
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN, United States
| | - Jean-Michel Michno
- Bioinformatics and Computational Biology Graduate Program, University of Minnesota, Minneapolis, MN, United States
| | - Erin Gilbert
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, United States
| | - Feng Li
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, United States
| | - Marisa E. Miller
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, United States
| | - Chad L. Myers
- Bioinformatics and Computational Biology Graduate Program, University of Minnesota, Minneapolis, MN, United States
- Department of Computer Science and Engineering, University of Minnesota, Minneapolis, MN, United States
| | | | - John P. Vogel
- Joint Genome Institute, Walnut Creek, CA, United States
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Brian J. Steffenson
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, United States
| | - Shahryar F. Kianian
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, United States
- USDA-ARS Cereal Disease Laboratory, St. Paul, MN, United States
| | - Cory D. Hirsch
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, United States
| | - Melania Figueroa
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Canberra, ACT, Australia
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Miller ME, Nazareno ES, Rottschaefer SM, Riddle J, Dos Santos Pereira D, Li F, Nguyen-Phuc H, Henningsen EC, Persoons A, Saunders DGO, Stukenbrock E, Dodds PN, Kianian SF, Figueroa M. Increased virulence of Puccinia coronata f. sp.avenae populations through allele frequency changes at multiple putative Avr loci. PLoS Genet 2020; 16:e1009291. [PMID: 33370783 PMCID: PMC7793281 DOI: 10.1371/journal.pgen.1009291] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 01/08/2021] [Accepted: 12/04/2020] [Indexed: 12/17/2022] Open
Abstract
Pathogen populations are expected to evolve virulence traits in response to resistance deployed in agricultural settings. However, few temporal datasets have been available to characterize this process at the population level. Here, we examined two temporally separated populations of Puccinia coronata f. sp. avenae (Pca), which causes crown rust disease in oat (Avena sativa) sampled from 1990 to 2015. We show that a substantial increase in virulence occurred from 1990 to 2015 and this was associated with a genetic differentiation between populations detected by genome-wide sequencing. We found strong evidence for genetic recombination in these populations, showing the importance of the alternate host in generating genotypic variation through sexual reproduction. However, asexual expansion of some clonal lineages was also observed within years. Genome-wide association analysis identified seven Avr loci associated with virulence towards fifteen Pc resistance genes in oat and suggests that some groups of Pc genes recognize the same pathogen effectors. The temporal shift in virulence patterns in the Pca populations between 1990 and 2015 is associated with changes in allele frequency in these genomic regions. Nucleotide diversity patterns at a single Avr locus corresponding to Pc38, Pc39, Pc55, Pc63, Pc70, and Pc71 showed evidence of a selective sweep associated with the shift to virulence towards these resistance genes in all 2015 collected isolates.
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Affiliation(s)
- Marisa E. Miller
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Eric S. Nazareno
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Susan M. Rottschaefer
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Jakob Riddle
- USDA-ARS Cereal Disease Laboratory, St. Paul, Minnesota, United States of America
| | - Danilo Dos Santos Pereira
- Environmental Genomics Group, Max Planck Institute for Evolutionary Biology, Plon, Germany
- Christian-Albrechts University of Kiel, Kiel Germany
| | - Feng Li
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Hoa Nguyen-Phuc
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Eva C. Henningsen
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Antoine Persoons
- INRA/Universite de Lorraine Interactions Abres/Microorganismes, Champenoux, France
| | | | - Eva Stukenbrock
- Environmental Genomics Group, Max Planck Institute for Evolutionary Biology, Plon, Germany
- Christian-Albrechts University of Kiel, Kiel Germany
| | - Peter N. Dodds
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Canberra, Australia
| | - Shahryar F. Kianian
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota, United States of America
- USDA-ARS Cereal Disease Laboratory, St. Paul, Minnesota, United States of America
| | - Melania Figueroa
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Canberra, Australia
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Miller ME, Muhsen S, Zabor EC, Flynn J, Olcese C, Giri D, Van Zee KJ, Pilewskie M. Abstract P5-18-01: Risk of contralateral breast cancer (CBC) in women with ductal carcinoma in situ (DCIS) with and without and synchronous lobular carcinoma in situ (LCIS). Cancer Res 2019. [DOI: 10.1158/1538-7445.sabcs18-p5-18-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: LCIS is considered a risk factor for bilateral breast cancer, but the effect of LCIS diagnosed concurrently with DCIS is not known. We sought to compare CBC and ipsilateral breast tumor recurrence (IBTR) rates in women with DCIS with and without synchronous LCIS treated with breast conserving surgery (BCS).
Methods: A prospectively maintained database of DCIS patients undergoing BCS from 2000-2011 was used to identify women with a contralateral breast at risk. Patients with synchronous ipsilateral LCIS found at core needle biopsy or surgical excision were included in the “DCIS + LCIS” group; those with contralateral or bilateral LCIS were excluded. Associations of patient, tumor, and treatment factors with CBC and IBTR were evaluated using logistic regression.
Results: Of the 1888 patients identified, 1475 (78%) had DCIS only and 413 (22%) had DCIS with synchronous LCIS. Median follow-up was 7.5 years (range 0-17 years). 305 patients had a subsequent breast event; 216 IBTR and 89 CBC.
The 5 and 10-year cumulative incidence of IBTR was similar in both groups: 6.3% and 14.4% for DCIS only, compared with 5.9% and 14.0% for DCIS + LCIS (p = 0.94), respectively. The 5 and 10-year cumulative incidence of CBC was significantly greater in the DCIS + LCIS group: 5.7% and 10.0%, compared with 2.4% and 5.0% for DCIS only (p < 0.001).
Table 1 summarizes uni-and multi-variable analyses of risk factors associated with CBC and IBTR among women with DCIS treated with BCS. After adjustment for other factors, CBC risk was more than 2-fold higher in the DCIS + LCIS group compared with the DCIS only group (HR 2.37, 95% CI 1.54-3.65, p < 0.001). There was no difference in IBTR risk based on presence of synchronous LCIS. Younger age and receipt of endocrine therapy were significantly associated with decreased risk of CBC.
Table 1:Risk factors associated with CBC and IBTR in patients with DCIS treated with BCS Univariate Analysis Multivariate Analysis Hazard Ratio (95% CI) Hazard Ratio (95% CI) CBC IBTR CBC IBTRAge (continuous)1.02 (1.01-1.04) *0.99 (0.98-1.0)1.02 (1.0-1.04) *0.99 (0.97-1.0) *Presentation Radiologic1111Clinical0.36 (0.11-1.14)1.56 (1.05-2.3) *0.41 (0.13-1.31)1.67 (1.12-2.47) *Family history Yes1.32 (0.87-2.01)1.0 (0.76-1.32)1.33 (0.87-2.03)1.03 (0.78-1.35)Grade Low1111Intermediate/high1.83 (1.0-3.37)1.32 (0.93-1.88)1.74 (0.92-3.29)1.62 (1.11-2.35) *Radiation Yes1.16 (0.75-1.8)0.7 (0.54-0.92) *1.14 (0.71-1.82)0.64 (0.48-0.86) *Endocrine Therapy Yes0.43 (0.23-0.81) *0.51 (0.35-0.74) *0.42 (0.22-0.8) *0.53 (0.36-0.77) *DCIS group DCIS only1111DCIS + LCIS2.28 (1.49-3.5) *0.99 (0.71-1.36)2.37 (1.54-3.65) *0.99 (0.71-1.37)* p < 0.05
Conclusions: LCIS diagnosed concurrently with DCIS is not associated with IBTR, but increases the risk of CBC two-fold. Endocrine therapy should be considered both for the index DCIS and for prevention of subsequent CBC.
Citation Format: Miller ME, Muhsen S, Zabor EC, Flynn J, Olcese C, Giri D, Van Zee KJ, Pilewskie M. Risk of contralateral breast cancer (CBC) in women with ductal carcinoma in situ (DCIS) with and without and synchronous lobular carcinoma in situ (LCIS) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-18-01.
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Affiliation(s)
- ME Miller
- Case Western Reserve University, University Hospitals, Cleveland, OH; Memorial Sloan Kettering Cancer Center, New York, NY
| | - S Muhsen
- Case Western Reserve University, University Hospitals, Cleveland, OH; Memorial Sloan Kettering Cancer Center, New York, NY
| | - EC Zabor
- Case Western Reserve University, University Hospitals, Cleveland, OH; Memorial Sloan Kettering Cancer Center, New York, NY
| | - J Flynn
- Case Western Reserve University, University Hospitals, Cleveland, OH; Memorial Sloan Kettering Cancer Center, New York, NY
| | - C Olcese
- Case Western Reserve University, University Hospitals, Cleveland, OH; Memorial Sloan Kettering Cancer Center, New York, NY
| | - D Giri
- Case Western Reserve University, University Hospitals, Cleveland, OH; Memorial Sloan Kettering Cancer Center, New York, NY
| | - KJ Van Zee
- Case Western Reserve University, University Hospitals, Cleveland, OH; Memorial Sloan Kettering Cancer Center, New York, NY
| | - M Pilewskie
- Case Western Reserve University, University Hospitals, Cleveland, OH; Memorial Sloan Kettering Cancer Center, New York, NY
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Omidvar V, Dugyala S, Li F, Rottschaefer SM, Miller ME, Ayliffe M, Moscou MJ, Kianian SF, Figueroa M. Detection of Race-Specific Resistance Against Puccinia coronata f. sp. avenae in Brachypodium Species. Phytopathology 2018; 108:1443-1454. [PMID: 29923800 DOI: 10.1094/phyto-03-18-0084-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Oat crown rust caused by Puccinia coronata f. sp. avenae is the most destructive foliar disease of cultivated oat. Characterization of genetic factors controlling resistance responses to Puccinia coronata f. sp. avenae in nonhost species could provide new resources for developing disease protection strategies in oat. We examined symptom development and fungal colonization levels of a collection of Brachypodium distachyon and B. hybridum accessions infected with three North American P. coronata f. sp. avenae isolates. Our results demonstrated that colonization phenotypes are dependent on both host and pathogen genotypes, indicating a role for race-specific responses in these interactions. These responses were independent of the accumulation of reactive oxygen species. Expression analysis of several defense-related genes suggested that salicylic acid and ethylene-mediated signaling but not jasmonic acid are components of resistance reaction to P. coronata f. sp. avenae. Our findings provide the basis to conduct a genetic inheritance study to examine whether effector-triggered immunity contributes to nonhost resistance to P. coronata f. sp. avenae in Brachypodium spp.
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Affiliation(s)
- Vahid Omidvar
- First, second, third, fourth, fifth, eighth, and ninth authors: Plant Pathology, University of Minnesota, St. Paul; sixth author: CSIRO Agriculture and Food, ACT, Australia; seventh author: The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, U.K.; eighth author: Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service, St. Paul, MN, USA; and ninth author: Stakman-Borlaug Center for Sustainable Plant Health, University of Minnesota, St. Paul
| | - Sheshanka Dugyala
- First, second, third, fourth, fifth, eighth, and ninth authors: Plant Pathology, University of Minnesota, St. Paul; sixth author: CSIRO Agriculture and Food, ACT, Australia; seventh author: The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, U.K.; eighth author: Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service, St. Paul, MN, USA; and ninth author: Stakman-Borlaug Center for Sustainable Plant Health, University of Minnesota, St. Paul
| | - Feng Li
- First, second, third, fourth, fifth, eighth, and ninth authors: Plant Pathology, University of Minnesota, St. Paul; sixth author: CSIRO Agriculture and Food, ACT, Australia; seventh author: The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, U.K.; eighth author: Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service, St. Paul, MN, USA; and ninth author: Stakman-Borlaug Center for Sustainable Plant Health, University of Minnesota, St. Paul
| | - Susan M Rottschaefer
- First, second, third, fourth, fifth, eighth, and ninth authors: Plant Pathology, University of Minnesota, St. Paul; sixth author: CSIRO Agriculture and Food, ACT, Australia; seventh author: The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, U.K.; eighth author: Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service, St. Paul, MN, USA; and ninth author: Stakman-Borlaug Center for Sustainable Plant Health, University of Minnesota, St. Paul
| | - Marisa E Miller
- First, second, third, fourth, fifth, eighth, and ninth authors: Plant Pathology, University of Minnesota, St. Paul; sixth author: CSIRO Agriculture and Food, ACT, Australia; seventh author: The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, U.K.; eighth author: Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service, St. Paul, MN, USA; and ninth author: Stakman-Borlaug Center for Sustainable Plant Health, University of Minnesota, St. Paul
| | - Mick Ayliffe
- First, second, third, fourth, fifth, eighth, and ninth authors: Plant Pathology, University of Minnesota, St. Paul; sixth author: CSIRO Agriculture and Food, ACT, Australia; seventh author: The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, U.K.; eighth author: Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service, St. Paul, MN, USA; and ninth author: Stakman-Borlaug Center for Sustainable Plant Health, University of Minnesota, St. Paul
| | - Matthew J Moscou
- First, second, third, fourth, fifth, eighth, and ninth authors: Plant Pathology, University of Minnesota, St. Paul; sixth author: CSIRO Agriculture and Food, ACT, Australia; seventh author: The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, U.K.; eighth author: Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service, St. Paul, MN, USA; and ninth author: Stakman-Borlaug Center for Sustainable Plant Health, University of Minnesota, St. Paul
| | - Shahryar F Kianian
- First, second, third, fourth, fifth, eighth, and ninth authors: Plant Pathology, University of Minnesota, St. Paul; sixth author: CSIRO Agriculture and Food, ACT, Australia; seventh author: The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, U.K.; eighth author: Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service, St. Paul, MN, USA; and ninth author: Stakman-Borlaug Center for Sustainable Plant Health, University of Minnesota, St. Paul
| | - Melania Figueroa
- First, second, third, fourth, fifth, eighth, and ninth authors: Plant Pathology, University of Minnesota, St. Paul; sixth author: CSIRO Agriculture and Food, ACT, Australia; seventh author: The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, U.K.; eighth author: Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service, St. Paul, MN, USA; and ninth author: Stakman-Borlaug Center for Sustainable Plant Health, University of Minnesota, St. Paul
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Fielding RA, Fielding RA, Kritchevsky S, Beavers DP, Walston JD, Stowe CL, Miller ME, Radziszewska B. RATIONALE AND AIMS OF THE ENABLING REDUCTION OF LOW-GRADE INFLAMMATION IN SENIORS: THE ENRGISE PILOT STUDY. Innov Aging 2018. [DOI: 10.1093/geroni/igy023.1650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- R A Fielding
- Exercise Physiology and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA, Boston, Massachusetts, United States
| | - R A Fielding
- Nutrition, Exercise Physiology, and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA
| | - S Kritchevsky
- Sticht Center on Aging, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - D P Beavers
- Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - J D Walston
- Johns Hopkins Asthma and Allergy Center, Baltimore, MD, USA
| | - C L Stowe
- Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - M E Miller
- Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - B Radziszewska
- Clinical Trials Branch, Division of Geriatrics and Clinical Gerontology, National Institute on Aging, Bethesda, MD, USA
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9
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Moghimi A, Yang C, Miller ME, Kianian SF, Marchetto PM. A Novel Approach to Assess Salt Stress Tolerance in Wheat Using Hyperspectral Imaging. Front Plant Sci 2018; 9:1182. [PMID: 30197650 PMCID: PMC6117507 DOI: 10.3389/fpls.2018.01182] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 07/24/2018] [Indexed: 05/22/2023]
Abstract
Salinity stress has significant adverse effects on crop productivity and yield. The primary goal of this study was to quantitatively rank salt tolerance in wheat using hyperspectral imaging. Four wheat lines were assayed in a hydroponic system with control and salt treatments (0 and 200 mM NaCl). Hyperspectral images were captured one day after salt application when there were no visual symptoms. Subsequent to necessary preprocessing tasks, two endmembers, each representing one of the treatment, were identified in each image using successive volume maximization. To simplify image analysis and interpretation, similarity of all pixels to the salt endmember was calculated by a technique proposed in this study, referred to as vector-wise similarity measurement. Using this approach allowed high-dimensional hyperspectral images to be reduced to one-dimensional gray-scale images while retaining all relevant information. Two methods were then utilized to analyze the gray-scale images: minimum difference of pair assignments and Bayesian method. The rankings of both methods were similar and consistent with the expected ranking obtained by conventional phenotyping experiments and historical evidence of salt tolerance. This research highlights the application of machine learning in hyperspectral image analysis for phenotyping of plants in a quantitative, interpretable, and non-invasive manner.
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Affiliation(s)
- Ali Moghimi
- Department of Bioproducts and Biosystems Engineering, University of Minnesota, Minneapolis, MN, United States
| | - Ce Yang
- Department of Bioproducts and Biosystems Engineering, University of Minnesota, Minneapolis, MN, United States
| | - Marisa E. Miller
- Cereal Disease Laboratory, USDA-ARS, Saint Paul, MN, United States
- Department of Plant Pathology, University of Minnesota, Minneapolis, MN, United States
| | - Shahryar F. Kianian
- Cereal Disease Laboratory, USDA-ARS, Saint Paul, MN, United States
- Department of Plant Pathology, University of Minnesota, Minneapolis, MN, United States
| | - Peter M. Marchetto
- Department of Bioproducts and Biosystems Engineering, University of Minnesota, Minneapolis, MN, United States
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10
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Rines HW, Miller ME, Carson M, Chao S, Tiede T, Wiersma J, Kianian SF. Identification, introgression, and molecular marker genetic analysis and selection of a highly effective novel oat crown rust resistance from diploid oat, Avena strigosa. Theor Appl Genet 2018; 131:721-733. [PMID: 29222636 DOI: 10.1007/s00122-017-3031-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 11/25/2017] [Indexed: 06/07/2023]
Abstract
Oat crown rust is one of the most damaging diseases of oat. We identified a new source of resistance and developed KASP and TaqMan markers for selection in breeding programs. A new highly effective resistance to oat crown rust (Puccinia coronata f. sp. avenae) was identified in the diploid oat Avena strigosa PI 258731 and introgressed into hexaploid cultivated oat. Young plants with this resistance show moderate susceptibility, whereas older plant tissues and adult plants are resistant with no virulent isolates encountered in over 8 years of testing. Resistance was incorporated into hexaploid oat by embryo rescue, colchicine chromosome doubling followed by backcrosses with a hexaploid parent, and selection for stable transmission of resistance. To mitigate flag leaf and panicle chlorosis/necrosis associated with the resistance, crosses were made with derived resistant lines to breeding lines of divergent parentage followed by selection. Subsequently, two F2 sister lines, termed MNBT1020-1 and MNBT1021-1, were identified in which the chlorosis/necrosis was reduced. These two lines performed well in replicated multi-location state trials in 2015 and 2016 out-yielding all cultivar entries. Segregating F2:3 plants resulting from crosses of MNBT lines to susceptible parents were genotyped with the oat 6K SNP array, and SNP loci with close linkage to the resistance were identified. KASP assays generated from linked SNPs showed accurate discrimination of the resistance in derivatives of the resistant MNBT lines crossed to susceptible breeding lines. A TaqMan marker was developed and correctly identified homozygous resistance in over 95% of 379 F4 plants when rust was scored in F4:5 plants in the field. Thus, a novel highly effective resistance and associated molecular markers are available for use in breeding, genetic analysis, and functional studies.
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Affiliation(s)
- Howard W Rines
- USDA-ARS Plant Sciences Research Unit, St. Paul, MN, 55108, USA
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN, 55108, USA
| | - Marisa E Miller
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, 55108, USA
| | - Martin Carson
- USDA-ARS Cereal Disease Laboratory, St. Paul, MN, 55108, USA
| | - Shiaoman Chao
- USDA-ARS, Cereal Crops Research Unit, Fargo, ND, 58102, USA
| | - Tyler Tiede
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN, 55108, USA
| | - Jochum Wiersma
- Department of Agronomy and Plant Genetics, University of Minnesota, Crookston, MN, 56716, USA
| | - Shahryar F Kianian
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, 55108, USA.
- USDA-ARS Cereal Disease Laboratory, St. Paul, MN, 55108, USA.
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11
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Schwessinger B, Sperschneider J, Cuddy WS, Garnica DP, Miller ME, Taylor JM, Dodds PN, Figueroa M, Park RF, Rathjen JP. A Near-Complete Haplotype-Phased Genome of the Dikaryotic Wheat Stripe Rust Fungus Puccinia striiformis f. sp. tritici Reveals High Interhaplotype Diversity. mBio 2018; 9:e02275-17. [PMID: 29463659 PMCID: PMC5821087 DOI: 10.1128/mbio.02275-17] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 01/09/2018] [Indexed: 01/01/2023] Open
Abstract
A long-standing biological question is how evolution has shaped the genomic architecture of dikaryotic fungi. To answer this, high-quality genomic resources that enable haplotype comparisons are essential. Short-read genome assemblies for dikaryotic fungi are highly fragmented and lack haplotype-specific information due to the high heterozygosity and repeat content of these genomes. Here, we present a diploid-aware assembly of the wheat stripe rust fungus Puccinia striiformis f. sp. tritici based on long reads using the FALCON-Unzip assembler. Transcriptome sequencing data sets were used to infer high-quality gene models and identify virulence genes involved in plant infection referred to as effectors. This represents the most complete Puccinia striiformis f. sp. tritici genome assembly to date (83 Mb, 156 contigs, N50 of 1.5 Mb) and provides phased haplotype information for over 92% of the genome. Comparisons of the phase blocks revealed high interhaplotype diversity of over 6%. More than 25% of all genes lack a clear allelic counterpart. When we investigated genome features that potentially promote the rapid evolution of virulence, we found that candidate effector genes are spatially associated with conserved genes commonly found in basidiomycetes. Yet, candidate effectors that lack an allelic counterpart are more distant from conserved genes than allelic candidate effectors and are less likely to be evolutionarily conserved within the P. striiformis species complex and Pucciniales In summary, this haplotype-phased assembly enabled us to discover novel genome features of a dikaryotic plant-pathogenic fungus previously hidden in collapsed and fragmented genome assemblies.IMPORTANCE Current representations of eukaryotic microbial genomes are haploid, hiding the genomic diversity intrinsic to diploid and polyploid life forms. This hidden diversity contributes to the organism's evolutionary potential and ability to adapt to stress conditions. Yet, it is challenging to provide haplotype-specific information at a whole-genome level. Here, we take advantage of long-read DNA sequencing technology and a tailored-assembly algorithm to disentangle the two haploid genomes of a dikaryotic pathogenic wheat rust fungus. The two genomes display high levels of nucleotide and structural variations, which lead to allelic variation and the presence of genes lacking allelic counterparts. Nonallelic candidate effector genes, which likely encode important pathogenicity factors, display distinct genome localization patterns and are less likely to be evolutionary conserved than those which are present as allelic pairs. This genomic diversity may promote rapid host adaptation and/or be related to the age of the sequenced isolate since last meiosis.
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Affiliation(s)
- Benjamin Schwessinger
- Research School of Biology, the Australian National University, Acton, ACT, Australia
| | - Jana Sperschneider
- Centre for Environment and Life Sciences, CSIRO Agriculture and Food, Perth, WA, Australia
| | - William S Cuddy
- Plant Breeding Institute, Faculty of Agriculture and Environment, the University of Sydney, Narellan, NSW, Australia
- NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, NSW, Australia
| | - Diana P Garnica
- Research School of Biology, the Australian National University, Acton, ACT, Australia
| | - Marisa E Miller
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota, USA
| | - Jennifer M Taylor
- Black Mountain Laboratories, CSIRO Agriculture and Food, Canberra, ACT, Australia
| | - Peter N Dodds
- Black Mountain Laboratories, CSIRO Agriculture and Food, Canberra, ACT, Australia
| | - Melania Figueroa
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota, USA
- Stakman-Borlaug Center for Sustainable Plant Health, University of Minnesota, St. Paul, Minnesota, USA
| | - Robert F Park
- Plant Breeding Institute, Faculty of Agriculture and Environment, the University of Sydney, Narellan, NSW, Australia
| | - John P Rathjen
- Research School of Biology, the Australian National University, Acton, ACT, Australia
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12
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Miller ME, Zhang Y, Omidvar V, Sperschneider J, Schwessinger B, Raley C, Palmer JM, Garnica D, Upadhyaya N, Rathjen J, Taylor JM, Park RF, Dodds PN, Hirsch CD, Kianian SF, Figueroa M. De Novo Assembly and Phasing of Dikaryotic Genomes from Two Isolates of Puccinia coronata f. sp. avenae, the Causal Agent of Oat Crown Rust. mBio 2018; 9:e01650-17. [PMID: 29463655 PMCID: PMC5821079 DOI: 10.1128/mbio.01650-17] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 01/09/2018] [Indexed: 01/18/2023] Open
Abstract
Oat crown rust, caused by the fungus Pucinnia coronata f. sp. avenae, is a devastating disease that impacts worldwide oat production. For much of its life cycle, P. coronata f. sp. avenae is dikaryotic, with two separate haploid nuclei that may vary in virulence genotype, highlighting the importance of understanding haplotype diversity in this species. We generated highly contiguous de novo genome assemblies of two P. coronata f. sp. avenae isolates, 12SD80 and 12NC29, from long-read sequences. In total, we assembled 603 primary contigs for 12SD80, for a total assembly length of 99.16 Mbp, and 777 primary contigs for 12NC29, for a total length of 105.25 Mbp; approximately 52% of each genome was assembled into alternate haplotypes. This revealed structural variation between haplotypes in each isolate equivalent to more than 2% of the genome size, in addition to about 260,000 and 380,000 heterozygous single-nucleotide polymorphisms in 12SD80 and 12NC29, respectively. Transcript-based annotation identified 26,796 and 28,801 coding sequences for isolates 12SD80 and 12NC29, respectively, including about 7,000 allele pairs in haplotype-phased regions. Furthermore, expression profiling revealed clusters of coexpressed secreted effector candidates, and the majority of orthologous effectors between isolates showed conservation of expression patterns. However, a small subset of orthologs showed divergence in expression, which may contribute to differences in virulence between 12SD80 and 12NC29. This study provides the first haplotype-phased reference genome for a dikaryotic rust fungus as a foundation for future studies into virulence mechanisms in P. coronata f. sp. avenaeIMPORTANCE Disease management strategies for oat crown rust are challenged by the rapid evolution of Puccinia coronata f. sp. avenae, which renders resistance genes in oat varieties ineffective. Despite the economic importance of understanding P. coronata f. sp. avenae, resources to study the molecular mechanisms underpinning pathogenicity and the emergence of new virulence traits are lacking. Such limitations are partly due to the obligate biotrophic lifestyle of P. coronata f. sp. avenae as well as the dikaryotic nature of the genome, features that are also shared with other important rust pathogens. This study reports the first release of a haplotype-phased genome assembly for a dikaryotic fungal species and demonstrates the amenability of using emerging technologies to investigate genetic diversity in populations of P. coronata f. sp. avenae.
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Affiliation(s)
- Marisa E Miller
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota, USA
| | - Ying Zhang
- Supercomputing Institute for Advanced Computational Research, University of Minnesota, Minneapolis, Minnesota, USA
| | - Vahid Omidvar
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota, USA
| | - Jana Sperschneider
- Centre for Environment and Life Sciences, Commonwealth Scientific and Industrial Research Organization, Agriculture and Food, Perth, WA, Australia
| | - Benjamin Schwessinger
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Castle Raley
- Leidos Biomedical Research, Frederick, Maryland, USA
| | - Jonathan M Palmer
- Center for Forest Mycology Research, Northern Research Station, USDA Forest Service, Madison, Wisconsin, USA
| | - Diana Garnica
- Agriculture and Food, Commonwealth Scientific and Industrial Research Organization, Canberra, ACT, Australia
| | - Narayana Upadhyaya
- Agriculture and Food, Commonwealth Scientific and Industrial Research Organization, Canberra, ACT, Australia
| | - John Rathjen
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Jennifer M Taylor
- Agriculture and Food, Commonwealth Scientific and Industrial Research Organization, Canberra, ACT, Australia
| | - Robert F Park
- Plant Breeding Institute, Faculty of Agriculture and Environment, School of Life and Environmental Sciences, University of Sydney, Narellan, NSW, Australia
| | - Peter N Dodds
- Agriculture and Food, Commonwealth Scientific and Industrial Research Organization, Canberra, ACT, Australia
| | - Cory D Hirsch
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota, USA
| | - Shahryar F Kianian
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota, USA
- USDA-ARS Cereal Disease Laboratory, St. Paul, Minnesota, USA
| | - Melania Figueroa
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota, USA
- Stakman-Borlaug Center for Sustainable Plant Health, University of Minnesota, St. Paul, Minnesota, USA
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Reid KF, Walkup MP, Katula JA, Sink KM, Anton S, Axtell R, Kerwin DR, King AC, Kramer F, Miller ME, Myers V, Rosano C, Studenski SA, Lopez OL, Verghese J, Fielding RA, Williamson J. Cognitive Performance Does not Limit Physical Activity Participation in the Lifestyle Interventions and Independence for Elders Pilot Study (LIFE-P). J Prev Alzheimers Dis 2017; 4:44-50. [PMID: 29188859 DOI: 10.14283/jpad.2016.107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVES We examined whether multiple domains of baseline cognitive performance were associated with prospective physical activity (PA) adherence in the Lifestyle Interventions and Independence for Elders Pilot study (LIFE-P). DESIGN, SETTING, PARTICIPANTS The LIFE-P study was a single-blind, multicenter, randomized controlled trial of a PA intervention compared to a successful aging educational intervention in sedentary, mobility-limited older adults. INTERVENTION A 12-month structured, moderate-intensity, multi-modal PA program that included walking, resistance training, and flexibility exercises. For the first 2 months (adoption), 3 center-based exercise sessions (40-60 min) / week were conducted. During the next 4 months (transition), center-based sessions were conducted 2 times / week. The subsequent maintenance phase consisted of optional once-to-twice-per-week center-based sessions and home-based PA. MEASUREMENTS Tests of executive and global cognitive functioning, working memory and psychomotor speed were administered at baseline. Median test scores were used to dichotomize participants into low or high cognitive performance groups. RESULTS 52 mobility-limited older adults (age: 76.9 ±5 yrs) were randomized to the PA arm of LIFE-P. Compared to participants with high cognitive performance, participants with low performance had similar PA adherence rates (all P ≥ 0.34). Furthermore, weak and non-significant univariate relationships were elicited between all measures of cognition and overall PA adherence levels (r values ranged: -0.20 to 0.12, P ≥ 0.12). CONCLUSION These data suggest that cognitive performance does not limit long-term PA adherence in mobility-limited older adults. Additional studies in larger cohorts are warranted to verify these findings.
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Affiliation(s)
- K F Reid
- Kieran F. Reid, PhD, MPH, Nutrition, Exercise Physiology and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, 711 Washington Street, Boston, MA 02111, USA.
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14
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Miller ME, Sanders PH. The Trappers Point Site (48SU1006): Early Archaic Adaptations and Pronghorn Procurement in the Upper Green River Basin, Wyoming. ACTA ACUST UNITED AC 2017; 45:39-52. [PMID: 17100016 DOI: 10.1080/2052546.2000.11932022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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15
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Miller ME, Liberatore KL, Kianian SF. Optimization and Comparative Analysis of Plant Organellar DNA Enrichment Methods Suitable for Next-generation Sequencing. J Vis Exp 2017. [PMID: 28784941 DOI: 10.3791/55528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Plant organellar genomes contain large, repetitive elements that may undergo pairing or recombination to form complex structures and/or sub-genomic fragments. Organellar genomes also exist in admixtures within a given cell or tissue type (heteroplasmy), and an abundance of subtypes may change throughout development or when under stress (sub-stoichiometric shifting). Next-generation sequencing (NGS) technologies are required to obtain deeper understanding of organellar genome structure and function. Traditional sequencing studies use several methods to obtain organellar DNA: (1) If a large amount of starting tissue is used, it is homogenized and subjected to differential centrifugation and/or gradient purification. (2) If a smaller amount of tissue is used (i.e., if seeds, material, or space is limited), the same process is performed as in (1), followed by whole-genome amplification to obtain sufficient DNA. (3) Bioinformatics analysis can be used to sequence the total genomic DNA and to parse out organellar reads. All these methods have inherent challenges and tradeoffs. In (1), it may be difficult to obtain such a large amount of starting tissue; in (2), whole-genome amplification could introduce a sequencing bias; and in (3), homology between nuclear and organellar genomes could interfere with assembly and analysis. In plants with large nuclear genomes, it is advantageous to enrich for organellar DNA to reduce sequencing costs and sequence complexity for bioinformatics analyses. Here, we compare a traditional differential centrifugation method with a fourth method, an adapted CpG-methyl pulldown approach, to separate the total genomic DNA into nuclear and organellar fractions. Both methods yield sufficient DNA for NGS, DNA that is highly enriched for organellar sequences, albeit at different ratios in mitochondria and chloroplasts. We present the optimization of these methods for wheat leaf tissue and discuss major advantages and disadvantages of each approach in the context of sample input, protocol ease, and downstream application.
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Affiliation(s)
- Marisa E Miller
- Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service; Department of Horticultural Science, University of Minnesota
| | - Katie L Liberatore
- Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service; Department of Plant Pathology, University of Minnesota
| | - Shahryar F Kianian
- Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service; Department of Plant Pathology, University of Minnesota;
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16
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Affiliation(s)
- Ali Moghimi
- Univ. of Minnesota, Twin Cities (United States)
| | - Ce Yang
- Univ. of Minnesota, Twin Cities (United States)
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17
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Liberatore KL, Dukowic-Schulze S, Miller ME, Chen C, Kianian SF. The role of mitochondria in plant development and stress tolerance. Free Radic Biol Med 2016; 100:238-256. [PMID: 27036362 DOI: 10.1016/j.freeradbiomed.2016.03.033] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 03/25/2016] [Accepted: 03/28/2016] [Indexed: 01/03/2023]
Abstract
Eukaryotic cells require orchestrated communication between nuclear and organellar genomes, perturbations in which are linked to stress response and disease in both animals and plants. In addition to mitochondria, which are found across eukaryotes, plant cells contain a second organelle, the plastid. Signaling both among the organelles (cytoplasmic) and between the cytoplasm and the nucleus (i.e. nuclear-cytoplasmic interactions (NCI)) is essential for proper cellular function. A deeper understanding of NCI and its impact on development, stress response, and long-term health is needed in both animal and plant systems. Here we focus on the role of plant mitochondria in development and stress response. We compare and contrast features of plant and animal mitochondrial genomes (mtDNA), particularly highlighting the large and highly dynamic nature of plant mtDNA. Plant-based tools are powerful, yet underutilized, resources for enhancing our fundamental understanding of NCI. These tools also have great potential for improving crop production. Across taxa, mitochondria are most abundant in cells that have high energy or nutrient demands as well as at key developmental time points. Although plant mitochondria act as integrators of signals involved in both development and stress response pathways, little is known about plant mtDNA diversity and its impact on these processes. In humans, there are strong correlations between particular mitotypes (and mtDNA mutations) and developmental differences (or disease). We propose that future work in plants should focus on defining mitotypes more carefully and investigating their functional implications as well as improving techniques to facilitate this research.
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Affiliation(s)
- Katie L Liberatore
- United States Department of Agriculture-Agricultural Research Service, Cereal Disease Laboratory, St. Paul, MN 55108, United States; Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, United States.
| | | | - Marisa E Miller
- United States Department of Agriculture-Agricultural Research Service, Cereal Disease Laboratory, St. Paul, MN 55108, United States; Department of Horticultural Science, University of Minnesota, St. Paul, MN 55108, United States
| | - Changbin Chen
- Department of Horticultural Science, University of Minnesota, St. Paul, MN 55108, United States
| | - Shahryar F Kianian
- United States Department of Agriculture-Agricultural Research Service, Cereal Disease Laboratory, St. Paul, MN 55108, United States; Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, United States
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Abstract
AIMS AND HYPOTHESIS In patients with Type 2 diabetes, intensive glycaemic control is associated with hypoglycaemia and possibly increased mortality. However, no blood biomarkers exist to predict these outcomes. Using participants from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study, we hypothesized that insulin deficiency and islet autoantibodies in patients with clinically diagnosed Type 2 diabetes would be associated with severe hypoglycaemia and death. METHODS A nested case-control study design was used. A case (n = 86) was a participant who died with at least one episode of severe hypoglycaemia, defined as hypoglycaemia requiring assistance, at any point during ACCORD follow-up. A control (n = 344) was a participant who did not die and did not have severe hypoglycaemia during follow-up. Each case was matched to four controls (glycaemic intervention arm, race, age and BMI). Baseline insulin deficiency (fasting C-peptide ≤ 0.15 nmol/l) and islet autoantibodies [glutamic acid decarboxylase (GAD), tyrosine phosphatase-related islet antigen 2 (IA2), insulin (IAA) and zinc transporter (ZnT8)] were measured. Conditional logistic regression with and without adjustment for age, BMI and diabetes duration was used. RESULTS Death during ACCORD in those who experienced at least one episode of severe hypoglycaemia was associated with insulin deficiency [OR 4.8 (2.1, 11.1): P < 0.0001], GAD antibodies [OR 2.3 (1.1, 5.1): P = 0.04], the presence of IAA or baseline insulin use [OR 6.1 (3.5,10.7): P < 0.0001], which remained significant after adjusting for age, BMI, and diabetes duration. There was no significant association with IA2 or ZnT8 antibodies. CONCLUSIONS In patients with Type 2 diabetes, C-peptide or GAD antibodies may serve as blood biomarkers predicting higher odds of subsequent severe hypoglycaemia and death. (Clinical Trial Registry No: NCT00000620, www.clinicaltrials.gov for original ACCORD study).
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Affiliation(s)
- L S Chow
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - H Chen
- Department of Biostatistical Sciences, Wake Forest School of Medicine, NC, USA
| | - M E Miller
- Department of Biostatistical Sciences, Wake Forest School of Medicine, NC, USA
| | - S M Marcovina
- Department of Medicine, University of Washington, WA, USA
| | - E R Seaquist
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA
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Farías RO, Garabalino MA, Ferraris S, Santa María J, Rovati O, Lange F, Trivillin VA, Monti Hughes A, Pozzi ECC, Thorp SI, Curotto P, Miller ME, Santa Cruz GA, Bortolussi S, Altieri S, Portu AM, Saint Martin G, Schwint AE, González SJ. Toward a clinical application of ex situ boron neutron capture therapy for lung tumors at the RA-3 reactor in Argentina. Med Phys 2016; 42:4161-73. [PMID: 26133616 DOI: 10.1118/1.4922158] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Many types of lung tumors have a very poor prognosis due to their spread in the whole organ volume. The fact that boron neutron capture therapy (BNCT) would allow for selective targeting of all the nodules regardless of their position, prompted a preclinical feasibility study of ex situ BNCT at the thermal neutron facility of RA-3 reactor in the province of Buenos Aires, Argentina. (l)-4p-dihydroxy-borylphenylalanine fructose complex (BPA-F) biodistribution studies in an adult sheep model and computational dosimetry for a human explanted lung were performed to evaluate the feasibility and the therapeutic potential of ex situ BNCT. METHODS Two kinds of boron biodistribution studies were carried out in the healthy sheep: a set of pharmacokinetic studies without lung excision, and a set that consisted of evaluation of boron concentration in the explanted and perfused lung. In order to assess the feasibility of the clinical application of ex situ BNCT at RA-3, a case of multiple lung metastases was analyzed. A detailed computational representation of the geometry of the lung was built based on a real collapsed human lung. Dosimetric calculations and dose limiting considerations were based on the experimental results from the adult sheep, and on the most suitable information published in the literature. In addition, a workable treatment plan was considered to assess the clinical application in a realistic scenario. RESULTS Concentration-time profiles for the normal sheep showed that the boron kinetics in blood, lung, and skin would adequately represent the boron behavior and absolute uptake expected in human tissues. Results strongly suggest that the distribution of the boron compound is spatially homogeneous in the lung. A constant lung-to-blood ratio of 1.3 ± 0.1 was observed from 80 min after the end of BPA-F infusion. The fact that this ratio remains constant during time would allow the blood boron concentration to be used as a surrogate and indirect quantification of the estimated value in the explanted healthy lung. The proposed preclinical animal model allowed for the study of the explanted lung. As expected, the boron concentration values fell as a result of the application of the preservation protocol required to preserve the lung function. The distribution of the boron concentration retention factor was obtained for healthy lung, with a mean value of 0.46 ± 0.14 consistent with that reported for metastatic colon carcinoma model in rat perfused lung. Considering the human lung model and suitable tumor control probability for lung cancer, a promising average fraction of controlled lesions higher than 85% was obtained even for a low tumor-to-normal boron concentration ratio of 2. CONCLUSIONS This work reports for the first time data supporting the validity of the ovine model as an adequate human surrogate in terms of boron kinetics and uptake in clinically relevant tissues. Collectively, the results and analysis presented would strongly suggest that ex situ whole lung BNCT irradiation is a feasible and highly promising technique that could greatly contribute to the treatment of metastatic lung disease in those patients without extrapulmonary spread, increasing not only the expected overall survival but also the resulting quality of life.
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Affiliation(s)
- R O Farías
- Comisión Nacional de Energía Atómica (CNEA), San Martín 1650, Argentina and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires 1033, Argentina
| | - M A Garabalino
- Comisión Nacional de Energía Atómica (CNEA), San Martín 1650, Argentina
| | - S Ferraris
- CIDME, Universidad Maimónides, Buenos Aires 1405, Argentina
| | - J Santa María
- CIDME, Universidad Maimónides, Buenos Aires 1405, Argentina
| | - O Rovati
- CIDME, Universidad Maimónides, Buenos Aires 1405, Argentina
| | - F Lange
- CIDME, Universidad Maimónides, Buenos Aires 1405, Argentina
| | - V A Trivillin
- Comisión Nacional de Energía Atómica (CNEA), San Martín 1650, Argentina and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires 1033, Argentina
| | - A Monti Hughes
- Comisión Nacional de Energía Atómica (CNEA), San Martín 1650, Argentina
| | - E C C Pozzi
- Comisión Nacional de Energía Atómica (CNEA), San Martín 1650, Argentina
| | - S I Thorp
- Comisión Nacional de Energía Atómica (CNEA), San Martín 1650, Argentina
| | - P Curotto
- Comisión Nacional de Energía Atómica (CNEA), San Martín 1650, Argentina
| | - M E Miller
- Comisión Nacional de Energía Atómica (CNEA), San Martín 1650, Argentina
| | - G A Santa Cruz
- Comisión Nacional de Energía Atómica (CNEA), San Martín 1650, Argentina
| | - S Bortolussi
- Istituto Nazionale di Fisica Nucleare, Sezione di Pavia 27100, Italy
| | - S Altieri
- Istituto Nazionale di Fisica Nucleare, Sezione di Pavia 27100, Italy and Dipartimento di Fisica, Università di Pavia, Pavia 27100, Italy
| | - A M Portu
- Comisión Nacional de Energía Atómica (CNEA), San Martín 1650, Argentina and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires 1033, Argentina
| | - G Saint Martin
- Comisión Nacional de Energía Atómica (CNEA), San Martín 1650, Argentina
| | - A E Schwint
- Comisión Nacional de Energía Atómica (CNEA), San Martín 1650, Argentina and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires 1033, Argentina
| | - S J González
- Comisión Nacional de Energía Atómica (CNEA), San Martín 1650, Argentina and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires 1033, Argentina
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Kianian PMA, Liberatore KL, Miller ME, Hegstad JB, Kianian SF. Dissecting Plant Chromosomes by the Use of Ionizing Radiation. Methods Mol Biol 2016; 1429:91-101. [PMID: 27511169 DOI: 10.1007/978-1-4939-3622-9_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Radiation treatment of genomes is used to generate chromosome breaks for numerous applications. This protocol describes the preparation of seeds and the determination of the optimal level of irradiation dosage for the creation of a radiation hybrid (RH) population. These RH lines can be used to generate high-resolution physical maps for the assembly of sequenced genomes as well as the fine mapping of genes. This procedure can also be used for mutation breeding and forward/reverse genetics.
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Affiliation(s)
- Penny M A Kianian
- Department of Horticultural Science, University of Minnesota, 1970 Folwell Ave., St. Paul, MN, 55108, USA.
| | - Katie L Liberatore
- USDA-ARS, Cereal Disease Laboratory, Department of Plant Pathology, University of Minnesota, 1551 Lindig Ave., St. Paul, MN, 55108, USA
| | - Marisa E Miller
- Department of Horticultural Science, University of Minnesota, 1970 Folwell Ave., St. Paul, MN, 55108, USA
| | - Justin B Hegstad
- Department of Plant Sciences, North Dakota State University, Fargo, ND, USA
| | - Shahryar F Kianian
- USDA-ARS, Cereal Disease Laboratory, Department of Plant Pathology, University of Minnesota, 1551 Lindig Ave., St. Paul, MN, 55108, USA.
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Simmons GM, Frick N, Wang A, Miller ME, Fragueiro D. Identifying information needs among children and teens living with haemophilia. Haemophilia 2013; 20:1-8. [PMID: 23809876 DOI: 10.1111/hae.12223] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2013] [Indexed: 11/29/2022]
Abstract
Transitioning from one life stage to the next can be difficult, but for those living with a chronic condition, it can be even more challenging. Children and adolescents with haemophilia need help to manage transitions while dealing with the complications of their disorder. The National Haemophilia Foundation (NHF), headquartered in New York City, has an extensive information centre on bleeding disorders, but it was not clear how much material existed on the topic of transition. The objectives of this project were to (i) assess the availability of literature about transition for children and adolescents living with haemophilia, (ii) determine which transition issues were the most relevant and (iii) develop and test information products that would address those transition issues. An inventory of NHF's resources and an environmental scan over the Internet was performed. Focus groups were conducted to determine messaging. Video prototypes containing messages were created, tested by focus groups and revised. The literature search yielded limited information available on transition for children and adolescents with haemophilia. Results of the formative research indicated that adolescents wanted more information on sports participation and disclosure of their condition (e.g. to peers, teachers, coaches, health care providers). Video was found to be the preferred delivery format. Children and adolescents living with haemophilia need information to help them transition through life. As a result of this study, two educational products were produced, but several more are recommended to guide these individuals in making healthy transitions into adulthood.
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Affiliation(s)
- G M Simmons
- Division of Blood Disorders, National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, GA, USA
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Miller ME, Moriarty JM, Linetsky M, Lai C, Ishiyama A. Intracochlear schwannoma presenting as diffuse cochlear enhancement: diagnostic challenges of a rare cause of deafness. Ir J Med Sci 2010; 181:131-4. [PMID: 20852964 PMCID: PMC3261412 DOI: 10.1007/s11845-010-0572-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2010] [Accepted: 09/03/2010] [Indexed: 11/24/2022]
Abstract
Intracochlear schwannoma is a rare, treatable, cause of unilateral hearing loss. Due to the small size, position, and variable clinical and imaging features, diagnosis presents a significant challenge and is often delayed. We present a case of a patient with an intracochlear schwannoma presenting as a diffuse enhancement of the cochlea, mimicking an infectious or inflammatory process. The absence of focal nodularity in this lesion on multiple high-resolution MRI examinations led to a delay of over 3 years from the patient's initial presentation to surgical diagnosis. Clinical history and examination, imaging features, pathologic findings, and surgical management options are described.
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Affiliation(s)
- M E Miller
- Department of Head and Neck Surgery, David Geffen School of Medicine, UCLA, 10833 LeConte Avenue, Los Angeles, CA 90095, USA
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Subbarayan P, Qin H, Pillai S, Lee JJ, Pfendt AP, Willing G, Miller ME, Dennis VA, Singh SR. Expression and characterization of a multivalent human respiratory syncytial virus protein. Mol Biol (Mosk) 2010; 44:477-487. [PMID: 20608172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Respiratory syncytial virus (RSV) has been recognized as one of the most common causes of severe respiratory tract infection in infants worldwide. As yet, a safe and effective vaccine has not been developed to protect humans from RSV. The F and G surface proteins have been widely investigated due to their potential to induce protective immunity. In addition, the M2 protein has been shown to be important in inducing a T-cell response. Our project involved the cloning of the immunodominant regions of the RSV F, M2 and G proteins into a bacterial vector, pET-32a (+). The recombinant RFM2G protein was expressed in Escherichia coli and purified using His Bind columns. The purified rRFM2G protein was analyzed by polyacrylamide gel electrophoresis and Western blotting. The predicted structure of the recombinant protein built by the Swiss PDB Viewer program suggested a rod shape with a distinct swollen head and neck which was confirmed by transmission electron microscopy and atomic force microscopy. BALB/c female mice were immunized with either RSV, rRFM2G alone, or rRFM2G in combination with flagellin as a mucosal adjuvant. Serum was collected on days 0, 14, 28 and 49 to assess the immune response by Enzyme-linked immunosorbent assay. Intranasal immunization of mice with the rRFM2G protein yielded significantly high serum IgG titers. Co-administration of the rRFM2G protein with flagellin did not augment the serum antibody response.
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Affiliation(s)
- P Subbarayan
- Center for NanoBiotechnology Research, Alabama State University, 915 South Jackson Street, Montgomery, AL 36101, USA
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Abstract
One thousand two hundred and forty-five Sydney injecting drug users (IDUs) were interviewed by questionnaire in 1989 to determine demographic and behavioural characteristics. One-sixth (16.7%) were considered to be at low risk of HIV from either needle sharing or sexual transmission as they had either never shared injecting equipment, or had not shared for years, or cleaned their injecting equipment effectively on 100% of the occasions when they did share; and were either celibate or monogamous or, if they had multiple partners, had not had unsafe sex in the previous 6 months. Over half (50.7%) had either unsafe injecting or sexual behaviour with the remaining third (32.6%) engaging in both unsafe injecting and sexual practises. Women were more at risk from sharing injection equipment than men but men were more at risk from sexual transmission than women. Increasing age was associated with greater likelihood of safer sex but age had no effect on injecting practises. There was no relationship between unsafe injecting and sexual practises. Amphetamine use was associated with low risk injecting practises while heroin use was associated with low risk sexual transmission. These findings indicate appreciable residual risk behaviour sufficient to allow for at least a slow diffusion of HIV among injecting drug users.
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Affiliation(s)
- A Wodak
- Drug and Alcohol Services, St Vincent's Hospital, Darlinghurst, NSW, Australia
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25
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Abstract
This paper reports on the incidence of unsafe injecting and the factors which influence this practice in a sample of 1245 Sydney injecting drug users (IDUs). Using a needle and syringe after someone else at some time in the last six months was reported in 41.6% of the sample. Taking into account those who claimed always to clean used needles with virucidal methods, 32.9% had placed themselves at risk of HIV infection from shared needles in the six months prior to interview.Seven factors were predictive of unsafe behaviour. These were (a) the amount spent per week on drugs, (b) the number of times a single needle was used prior to disposal, (c) having shared with a person who is now HIV infected, (d) having a regular sexual partner, (e) the proportion of times high, stoned or drunk when injecting, (f) being part of a group that injects together and (g) having been in prison.
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Affiliation(s)
- B R Crisp
- School of Social Administration, Flinders University, Adelaide, South Australia
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26
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Varghese BA, Miller ME, Hangartner TN. Estimation of bone strength from pediatric radiographs of the forearm. J Musculoskelet Neuronal Interact 2008; 8:379-390. [PMID: 19147976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
OBJECTIVE Bone strength is a function of both material and architectural properties. However, bone geometry or architecture, which determines the distribution of bone, is an underappreciated determinant of bone strength. The aim of the study was to evaluate the contribution of only architecture to bone strength. METHODS We used 2-D (planar) geometric information from radiographs of human radii to construct 3-D finite-element models. To transition from 2-D to 3-D (volume) space, we assumed that all bone cross-sections were elliptical in shape. The finite-element models were subjected to cantilever loading to determine the locations in the bone with the highest propensity to fracture (points of maximum stress). The finite-element-analysis results of the models generated from radiographs of both normal (18) and temporary-brittle-bone-disease (11) infants were subjected to a receiver operating curve analysis. The area under the receiver operating curve was used to evaluate the power of a given bone-strength indicator in segregating the two populations. The actual choice of the material properties (Young's modulus or Poisson's ratio) was not critical for this study, since the finite element analyses were designed to capture the difference in the bone strength of the two populations only based on their architecture. Therefore, the material properties were assumed to be the same in both the normal and TBBD populations. RESULTS The area under the curve of the bending load required to cause fracture among the two populations was 0.82. Other bone-strength indicators, such as average section modulus, cortical thickness and bone length, were associated with an area under the curve of 0.75, 0.73 and 0.63, respectively. CONCLUSION The results of the finite-element-analysis suggest that the temporary-brittle-bone-disease population has an altered bone geometry, which increases susceptibility to fracture under normal bending loads.
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Affiliation(s)
- B A Varghese
- BioMedical Imaging Laboratory, Wright State University, OH 45435, USA
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Abstract
Iris yellow spot virus (IYSV; family Bunyaviridae, genus Tospovirus) has emerged as a potentially devastating and widespread virus of onion. IYSV was first reported in the United States from Idaho in 1993 and has since spread to many of the onion-producing areas (1). In South America, the most recent reports of the virus on onion were from Peru and Chile (2,4). In 2005, onion plants in Uvalde County, Texas exhibited necrotic lesions on leaves typical of IYSV and disease incidence approached 100% in some fields with yield loss and quality problems. Five of six plants tested were positive for IYSV with double antibody sandwich-enzyme linked immunosorbent assay (DAS-ELISA; Agdia Inc., Elkhart, IN). In 2006, similar lesions were observed on onion plants in Uvalde County and approximately 400 km south in Hidalgo and Cameron counties. Infection points generally started as a single plant near the edge of fields and spread to plants in a 3- to 4-m area after 1 to 2 weeks. Early-season disease incidence was low in onions grown for bulbs and transplants, <10% in 2006. Disease incidence increased in some fields until the crop was harvested. Leaves of symptomatic plants were tested for IYSV and Tomato spotted wilt virus (TSWV) using DAS-ELISA, and 18 of 23 samples from the Hidalgo County area and 12 of 21 samples from the Uvalde County area were positive for IYSV. All samples tested for TSWV from these counties were negative. Virus infection in some ELISA-positive plants was verified by reverse transcription-polymerase chain reaction (RT-PCR) using primers derived from the small RNA of IYSV. The primers flanked the IYSV nucleocapsid (N) gene (5'-TAA AAC AAA CAT TCA AAC AA-3' and 5'-CTC TTA AAC ACA TTT AAC AAG CAC-3' (3). RT-PCR gave a PCR product of expected size (approximately 1.2 kb). The DNA amplicon was cloned and sequenced (GenBank Accession No. DQ658242). Nucleotide sequence analysis confirmed the identity of the amplicon as that of IYSV N gene and sequence comparisons with known IYSV N gene sequences showed 95 to 98% sequence identity. The primary vector of IYSV, onion thrips (Thrips tabaci), is a widespread and destructive pest of onion in south Texas. The year-to-year incidence of IYSV and the severity of the disease will probably depend on the onion thrips population levels. Bulb yield reduction could be severe during years with high thrips populations. More research is needed to determine the impact of IYSV on bulb yield in Texas, the relationship between IYSV incidence and T. tabaci population levels, and oversummering hosts. To our knowledge, this is the first known report of IYSV in Texas. References: (1) D. H. Gent et al. Plant Dis. 88:446, 2004, (2) S. W. Mullis et al. Plant Dis. 90:377, 2006, (3) H. Pappu et al. Arch. Virol. 151:1015, 2006. (4) M. Rosales et al. Plant Dis. 89:1245, 2005.
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Affiliation(s)
| | | | | | - H R Pappu
- Washington State University, Pullman 99164-6430
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Isakeit T, Miller ME, Saldaña R, Barnes LW, McKemy JM, Palm ME, Zeller KA, DeVries-Paterson R, Levy L. First Report of Rust Caused by Phakopsora pachyrhizi on Soybean and Kudzu in Texas. Plant Dis 2006; 90:971. [PMID: 30781042 DOI: 10.1094/pd-90-0971a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The Asian soybean rust fungus, Phakopsora pachyrhizi H. Sydow & Sydow, was found on a 0.4-ha patch of kudzu (Pueraria lobata) near Dayton (Liberty County) in East Texas on November 2, 2005. Nearly 100% of the 300 leaflets examined were diseased with severity ranging from 5 to >100 lesions per leaflet. Eleven soybean fields as much as 20 km away were scouted and no infected plants were found. Asian soybean rust was also found on a 0.4-ha field of soybean (Glycine max cv. Vernal) on February 14, 2006 at the Texas A&M Agricultural Experiment Station in Weslaco (Hidalgo County) in the Lower Rio Grande Valley (LRGV) of Texas. Disease incidence was 100% (severity ranging from 5 to >100 lesions per leaflet) on 50 younger plants with green leaves along the edges of the field, whereas most of the plants in this field had senesced. These plants were not symptomatic and were at the R6 stage (full seed) when this field was previously scouted on December 19, 2005. Lesions on leaflets of kudzu and soybean were small and angular with erumpent uredinia typical of P. pachyrhizi. Urediniospores were ovoid or globose, hyaline, and measured 25 to 30 × 14 to 21 μm. Leaf samples with pustules were positive for P. pachyrhizi using enzyme-linked immunosorbent assay (ELISA) (Envirologix, Portland, ME). Morphological and polymerase chain reaction (PCR) identification of P. pachyrhizi from kudzu and soybean samples were confirmed by the USDA-APHIS-PPQ NIS and CPHST laboratories in Beltsville, MD as previously described (2). The kudzu in East Texas is not likely to support overwintering of the pathogen because it usually dies back during the winter. Leaves at this site were dead by January 17, 2006. This is the southernmost infestation of kudzu in Texas known to us. In contrast, the LRGV has a subtropical climate that would favor year-round survival of the fungus (3). This area, where 120 to 160 ha of soybeans are grown, may be a source of inoculum for soybean rust epidemics in the Midwest. Spore movement would follow the same pattern as seen with cereal rusts (1). However, soybeans are typically absent from the LRGV between late December and early March, so survival of the fungus during this interval would require other hosts. Regardless of whether the fungus overwinters here, or moves in from elsewhere, the LRGV spring crop could serve as an early indicator of a potential rust epidemic. References: (1) M. G. Eversmeyer and C. L. Kramer. Annu. Rev. Phytopathol. 38:491, 2000. (2) J. M. Mullen et al. Plant Dis. 90:112, 2006. (3) S. Pivonia et al. Plant Dis. 89:678, 2005.
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Affiliation(s)
- T Isakeit
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station
| | - M E Miller
- Department of Plant Pathology and Microbiology, Texas A&M University, Weslaco
| | - R Saldaña
- Department of Plant Pathology and Microbiology, Texas A&M University, Weslaco
| | - L W Barnes
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station
| | | | - M E Palm
- USDA-APHIS-PPQ-NIS, Beltsville, MD
| | - K A Zeller
- USDA-APHIS-PPQ-CPHST-NPGBL, Beltsville, MD
| | | | - L Levy
- USDA-APHIS-PPQ-CPHST-NPGBL, Beltsville, MD
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Miller ME, Holloway AC, Foster WG. Benzo-[a]-pyrene increases invasion in MDA-MB-231 breast cancer cells via increased COX-II expression and prostaglandin E2 (PGE2) output. Clin Exp Metastasis 2005; 22:149-56. [PMID: 16086235 DOI: 10.1007/s10585-005-6536-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2004] [Accepted: 04/21/2005] [Indexed: 01/28/2023]
Abstract
Benzo-[a]-pyrene (B[a]P), a carcinogenic component of cigarette smoke, has been shown to increase both COX-II expression and prostaglandin output in vascular smooth muscle and oral epithelial cells. In addition, invasive breast cancer cells have been reported to over express COX-II and PGE(2). Therefore, the objective of this study was to quantify the effect of increasing B[a]P concentrations on COX-II expression, PGE(2) output, and invasion using MDA-MB-231 cells, an invasive estrogen unresponsive breast cancer cell line. B[a]P significantly increased invasion in MDA-MB-231 cells at concentrations greater than 4 x 10(-8) M. Treatment of MDA-MB-231 cells with Vomitoxin (a selective COX-II inducer) enhanced invasion whereas co-treatment with NS398 (a selective COX-II inhibitor) attenuated B[a]P-induced invasion in MDA-MB-231 cells. Immunohistochemical staining and Western blots demonstrated a significant B[a]P treatment-induced increase in both the number of COX-II immunopositive MDA-MB-231 cells and COX-II protein levels. Moreover, B[a]P-treatment induced a profound (46 fold) increase in PGE(2) production by MDA-MB-231 cells. The aryl hydrocarbon receptor (AhR) antagonists resveratrol (RES) and alpha-naphthaflavone (alpha-NF) had no effect on their own, whereas B[a]P-induced invasion was significantly inhibited by co-treatment with RES and alpha-NF. Our data demonstrate that B[a]P-induced changes in invasion are mediated through augmented COX-II expression and PGE(2) production involving an AhR regulated pathway. Moreover, these results suggest a potential role for the AhR signalling pathway in breast cancer invasion.
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Affiliation(s)
- M E Miller
- Reproductive Biology Division, Department of Obstetrics & Gynecology, McMaster University, Hamilton, Ontario, Canada
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Miller ME, Mariani LE, Gonçalves-Carralves MLS, Skumanic M, Thorp SI. Implantable self-powered detector for on-line determination of neutron flux in patients during NCT treatment. Appl Radiat Isot 2005; 61:1033-7. [PMID: 15308188 DOI: 10.1016/j.apradiso.2004.05.041] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A novel system to determine thermal neutron flux in real time during NCT treatments was developed in the National Atomic Energy Commission of Argentina. The system is based on a special self-powered detector that can be implanted in patients owing to its small size and biocompatibility. High voltage is not required to operate this kind of detectors, which is a considerable advantage in terms of medical uses. By choosing the appropriate materials, it was possible to obtain a prototype with thermal neutron sensitivity providing for an adequate signal level in typical NCT thermal fluxes. It was also possible to minimize gamma response in order to neglect its contribution.
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Affiliation(s)
- M E Miller
- Instrumentation and Control Department, Division of Nuclear Reactors and Power Plants Activities, National Atomic Energy Commission (CNEA), Av. Del Libertador 8250, C1429BNP, Ciudad Autónoma de Buenos Aires, Argentina.
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Huang C, Kim Y, Caramori ML, Fish AJ, Rich SS, Miller ME, Russell GB, Mauer M. Cellular basis of diabetic nephropathy: III. In vitro GLUT1 mRNA expression and risk of diabetic nephropathy in type 1 diabetic patients. Diabetologia 2004; 47:1789-94. [PMID: 15502921 DOI: 10.1007/s00125-004-1533-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2004] [Accepted: 07/12/2004] [Indexed: 12/14/2022]
Abstract
AIMS/HYPOTHESIS Altered glucose transporter expression has been implicated in the pathogenesis of diabetic nephropathy. There is increasing evidence that genetic factors convey risk of, or protection from, diabetic nephropathy and that the behaviour of cultured skin fibroblasts from type 1 diabetic patients may reflect these genetic influences. This study aimed to compare GLUT1 mRNA expression levels in skin fibroblasts from type 1 diabetic patients with either rapid ("fast-track", n=25) or slow ("slow-track", n=25) development of diabetic nephropathy and from non-diabetic normal control subjects (controls, n=25). METHODS Skin fibroblasts were cultured in Dulbecco's Modified Eagle's Medium with 25 mmol/l glucose for 36 h. Total RNA was isolated, and GLUT1 mRNA levels were estimated by microarray analysis and RT-PCR. RESULTS Levels of GLUT1 mRNA expression in skin fibroblasts from "slow-track" patients were greater than those from "fast-track" patients (p=0.02), as initially detected by microarray. GLUT1 mRNA expression levels were confirmed by RT-PCR to be higher in skin fibroblasts from "slow-track" patients (4.59+/-2.04) than in those from "fast-track" patients (3.34+/-1.2, p=0.02), and were also higher than in skin fibroblasts from control subjects (3.52+/-1.66, p=0.03). There was no statistically significant difference between levels of expression in the "fast-track" patients and the control subjects. CONCLUSIONS/INTERPRETATION This finding is consistent with the presence of cellular protection factors against diabetic nephropathy in the "slow-track" patients. These factors could be associated with the regulation of the GLUT1 pathway and may be genetically determined.
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Affiliation(s)
- C Huang
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, Minnesota, USA
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Thamthiankul S, Moar WJ, Miller ME, Panbangred W. Improving the insecticidal activity of Bacillus thuringiensis subsp. aizawai against Spodoptera exigua by chromosomal expression of a chitinase gene. Appl Microbiol Biotechnol 2004; 65:183-92. [PMID: 15107949 DOI: 10.1007/s00253-004-1606-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2003] [Accepted: 02/28/2004] [Indexed: 11/30/2022]
Abstract
A transcriptionally fused gene comprising the P19 gene from Bacillus thuringiensis subsp. israelensis fused with a chitinase gene (chiBlA) from B. licheniformis was integrated into the B. thuringiensis subsp. aizawai BTA1 genome by homologous recombination. The resulting B. thuringiensis subsp. aizawai strain (INT1) showed growth and sporulation comparable with that of the wild-type strain. INT1 produced four chitinases of different molecular masses (i.e., 66, 55, 39, 36 kDa). Three of these (66, 55, 36 kDa) were derived from the cloned chiBlA gene, whereas the 39-kDa chitinase originated from BTA1. Using surface contamination bioassays, the 50% lethal concentration of lyophilized whole culture broth of INT1 against Spodoptera exigua neonate larvae was 12.2 microg/cm2, compared with 30.8 microg/cm2 for BTA1. Bioassays using filtered culture supernatant of INT1 (110 microg/cm2) together with trypsin-activated purified Cry1C protein of B. thuringiensis (1,280 ng/cm2) showed 75.0% mortality, compared with 56.7% mortality for Cry1C combined with BTA1 at the same concentration. Using scanning electron microscopy, clear perforations were observed in S. exigua fifth instar peritrophic membranes incubated with either crude or purified chitinase, or isolated from fifth instar S. exigua fed purified chitinase since the first instar. These results show that chitinase can increase the activity of B. thuringiensis subsp. aizawai against S. exigua. This is the first documentation of expressing a chimeric chitinase gene on the chromosome of B. thuringiensis; and chromosomal integration might be used as a potential technique for strain improvement.
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Affiliation(s)
- S Thamthiankul
- Department of Biotechnology, Faculty of Science, Mahidol University, Phayathai, Bangkok, 10400, Thailand
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Abstract
Recent evidence suggests oxytocin (OT) may regulate vascular tone. OT and its receptor (OTR) have been identified in the rat heart and great vessels. Expression of OT and OTR is increased in some tissues during pregnancy. We hypothesized that the OT/OTR system may be a physiological regulator of vascular tone and mediate the decreased vascular resistance noted during pregnancy. Using a wire myograph system, we measured changes in vascular tone in response to OT in small mesenteric arteries, uterine arcuate arteries, and thoracic aorta from nonpregnant and pregnant rats. Additionally, we used reverse transcriptase-polymerase chain reaction (RT-PCR) to measure mRNA for OTR in these vascular tissues. Although OTR mRNA was identified by RT-PCR, OT did not elicit a vasodilatory effect in any of the vessels studied. High concentrations of OT (>10(-8) M) caused vasoconstriction that was eliminated by a specific vasopressin V(1a) receptor antagonist. Although it may have an indirect effect in regulation of peripheral resistance, we conclude that OT is unlikely to play a direct role in the physiological regulation of vascular tone.
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MESH Headings
- Animals
- Aorta, Abdominal/drug effects
- Aorta, Abdominal/physiology
- Arteries/drug effects
- Arteries/physiology
- Female
- Gene Expression Regulation/drug effects
- Mesenteric Arteries/drug effects
- Mesenteric Arteries/physiology
- Methacholine Chloride/pharmacology
- Muscle Tonus/physiology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Oxytocin/genetics
- Oxytocin/pharmacology
- Phenylephrine/pharmacology
- Pregnancy
- Pregnancy, Animal/physiology
- Rats
- Rats, Sprague-Dawley
- Receptors, Oxytocin/genetics
- Receptors, Oxytocin/physiology
- Reverse Transcriptase Polymerase Chain Reaction
- Uterus/blood supply
- Uterus/drug effects
- Uterus/physiology
- Vasoconstriction/drug effects
- Vasoconstriction/physiology
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Affiliation(s)
- M E Miller
- Department of Obstetrics and Gynecology, University of Alberta, Edmonton, Alberta, Canada T6G 2S2
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Lester LA, Rich SS, Blumenthal MN, Togias A, Murphy S, Malveaux F, Miller ME, Dunston GM, Solway J, Wolf RL, Samet JM, Marsh DG, Meyers DA, Ober C, Bleecker ER. Ethnic differences in asthma and associated phenotypes: collaborative study on the genetics of asthma. J Allergy Clin Immunol 2001; 108:357-62. [PMID: 11544453 DOI: 10.1067/mai.2001.117796] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND In the Collaborative Study on the Genetics of Asthma, 314 families with 2584 subjects were characterized for asthma and allergy. OBJECTIVE The purpose of this investigation was to examine clinical heterogeneity observed in asthma and allergic characteristics among 3 ethnic groups (African American, white, and Hispanic family members). METHODS Pulmonary function parameters and asthma associated phenotypes were compared among the ethnic groups. RESULTS In comparison with the other groups, African American sibling pairs had a significantly lower baseline FEV(1) percent of predicted (P =.0001) and a higher rate of skin test reactivity to cockroach allergen (P =.0001); Hispanic sibling pairs had significantly more skin reactivity overall (P =.001); and white sibling pairs had significantly lower total serum IgE (P <.05). In addition, there were significantly more relatives with asthma among the African American families than among the white and the Hispanic families (P =.001). CONCLUSION Although different environmental backgrounds should be considered, these clinical differences could be due to differences in genetic susceptibility among the ethnic groups, such as those suggested by our previous genome screen.
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Abstract
This case report documents the application of transabdominal ultrasonography for detecting pregnancy and monitoring fetal development in an unanesthetized, unrestrained babirusa (Babyrousa babyrussa). A 4-yr-old multiparous female babirusa was trained to accept monitoring via transabdominal ultrasonography on a weekly basis postcoitus. Uterine changes associated with pregnancy were first detected at 30 days gestation. Three fetuses were first visualized on day 38, and two of the three fetuses were detectable until term. One fetus failed to develop and appeared to be resorbed between days 80 and 94 of the 161-day pregnancy. The growth of the remaining two fetuses was monitored via cranial measurements taken during the weekly scans throughout the pregnancy. By monitoring a subsequent pregnancy via ultrasound in the same female it was possible to confirm her tendency towards partial resorption, with earliest detection of uterine changes on day 32 and apparent resorption of one of three fetuses at approximately the midpoint of gestation. Two rectal scans of a different female under anesthesia at 28 and 50 days gestation showed stages of development comparable to those visualized transabdominally. However, the transabdominal scans produced better images of the reproductive tract, perhaps because of the close proximity of the pregnant uterus to the abdominal wall.
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Affiliation(s)
- E W Houston
- St. Louis Zoological Park, 1 Government Drive, St. Louis, Missouri 63110, USA
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36
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Abstract
Different G(1) cyclins confer functional specificity to the cyclin-dependent kinase (Cdk) Cdc28p in budding yeast. The Cln3p G(1) cyclin is localized primarily to the nucleus, while Cln2p is localized primarily to the cytoplasm. Both binding to Cdc28p and Cdc28p-dependent phosphorylation in the C-terminal region of Cln2p are independently required for efficient nuclear depletion of Cln2p, suggesting that this process may be physiologically regulated. The accumulation of hypophosphorylated Cln2 in the nucleus is an energy-dependent process, but may not involve the RAN GTPase. Phosphorylation of Cln2p is inefficient in small newborn cells obtained by elutriation, and this lowered phosphorylation correlates with reduced Cln2p nuclear depletion in newborn cells. Thus, Cln2p may have a brief period of nuclear residence early in the cell cycle. In contrast, the nuclear localization pattern of Cln3p is not influenced by Cdk activity. Cln3p localization requires a bipartite nuclear localization signal (NLS) located at the C terminus of the protein. This sequence is required for nuclear localization of Cln3p and is sufficient to confer nuclear localization to green fluorescent protein in a RAN-dependent manner. Mislocalized Cln3p, lacking the NLS, is much less active in genetic assays specific for Cln3p, but more active in assays normally specific for Cln2p, consistent with the idea that Cln3p localization explains a significant part of Clnp functional specificity.
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Affiliation(s)
- M E Miller
- The Rockefeller University, New York, New York 10021, USA
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37
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Rejeski WJ, Miller ME, Foy C, Messier S, Rapp S. Self-efficacy and the progression of functional limitations and self-reported disability in older adults with knee pain. J Gerontol B Psychol Sci Soc Sci 2001; 56:S261-5. [PMID: 11522807 DOI: 10.1093/geronb/56.5.s261] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES The prospective relationships between self-efficacy beliefs, in conjunction with measures of knee pain and knee strength, and subsequent decline in both physical performance and self-reported disability among older adults with knee pain were examined. METHODS In this prospective epidemiological trial, 480 men and women aged 65 years and older who had knee pain on most days of the week and difficulty with daily activity were followed for 30 months. RESULTS There was a significant interaction of baseline self-efficacy with baseline knee strength in predicting both self-reported disability and stair climb performance. Participants who had low self-efficacy and low strength at baseline had the largest 30-month decline in these outcomes. DISCUSSION These data underscore the important role that self-efficacy beliefs play in understanding functional decline with chronic disease and aging. Self-efficacy beliefs appear to be most important to functional decline in older adults when they are challenged by muscular weakness in the lower extremities.
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Affiliation(s)
- W J Rejeski
- Department of Health and Exercise Science, Wake Forest University, Winston-Salem, North Carolina 27109, USA.
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38
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Miller ME, Morgan TM, Espeland MA, Emerson SS. Group comparisons involving missing data in clinical trials: a comparison of estimates and power (size) for some simple approaches. Stat Med 2001; 20:2383-97. [PMID: 11512129 DOI: 10.1002/sim.904] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
When using 'intent-to-treat' approaches to compare outcomes between groups in clinical trials, analysts face a decision regarding how to account for missing observations. Most model-based approaches can be summarized as a process whereby the analyst makes assumptions about the distribution of the missing data in an attempt to obtain unbiased estimates that are based on functions of the observed data. Although pointed out by Rubin as often leading to biased estimates of variances, an alternative approach that continues to appear in the applied literature is to use fixed-value imputation of means for missing observations. The purpose of this paper is to provide illustrations of how several fixed-value mean imputation schemes can be formulated in terms of general linear models that characterize the means of distributions of missing observations in terms of the means of the distributions of observed data. We show that several fixed-value imputation strategies will result in estimated intervention effects that correspond to maximum likelihood estimates obtained under analogous assumptions. If the missing data process has been correctly characterized, hypothesis tests based on variances estimated using maximum likelihood techniques asymptotically have the correct size. In contrast, hypothesis tests performed using the uncorrected variance, obtained by applying standard complete data formula to singly imputed data, can provide either conservative or anticonservative results. Surprisingly, under several non-ignorable non-response scenarios, maximum likelihood based analyses can yield equivalent hypothesis tests to those obtained when analysing only the observed data.
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Affiliation(s)
- M E Miller
- Section on Biostatistics, Department of Public Health Sciences, Wake Forest University School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157-1063, USA.
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Miller ME, Rejeski WJ, Messier SP, Loeser RF. Modifiers of change in physical functioning in older adults with knee pain: the Observational Arthritis Study in Seniors (OASIS). Arthritis Rheum 2001; 45:331-9. [PMID: 11501720 DOI: 10.1002/1529-0131(200108)45:4<331::aid-art345>3.0.co;2-6] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE To ascertain predictors of decline in physical functioning among older adults reporting knee pain. METHODS The Observational Arthritis Study in Seniors was a longitudinal study of 480 adults over 65 years of age. Measurements of strength, sociodemographic characteristics, disease burden (including radiographic knee osteoarthritis [OA]), self-reported disability, and functional limitations were obtained on participants at baseline and at 15 and 30 months. RESULTS Radiographic evidence of OA at baseline was moderately associated with an increased decline in both transfer (P = 0.06) and ambulatory-based performance tasks (P = 0.04) but not in self-reported disability. This effect disappeared after accounting for baseline levels of knee pain intensity and knee strength. CONCLUSION Knee pain intensity and knee strength may mediate the relationship between radiographic evidence of knee OA and change in performance. Although it is not clear whether joint disease precedes or follows a decline in muscular strength, these results may help to identify subpopulations of older persons with knee OA who may benefit from interventions aimed at slowing the progression of disability related to transfer and ambulatory-based tasks.
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Affiliation(s)
- M E Miller
- Department of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1063, USA
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40
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Fryer GE, Green LA, Vojir CP, Krugman RD, Miyoshi TJ, Stine C, Miller ME. Hispanic versus white, non-Hispanic physician medical practices in Colorado. J Health Care Poor Underserved 2001; 12:342-51. [PMID: 11475551 DOI: 10.1353/hpu.2010.0811] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The purpose of the study was to extend the scope of earlier research on minority physicians attending to the needs of the poor and their own ethnicity by contrasting practice characteristics of Hispanic doctors in Colorado with those of their white, non-Hispanic counterparts. It was found that Hispanic physicians spent more hours per week in direct patient care, were more likely to have a primary care specialty, and were less often specialty board certified than white, non-Hispanic doctors. Hispanic generalists established practices in areas in which the percentages of the population that were (1) below poverty level, (2) Hispanic, (3) Hispanic and below poverty level, and (4) white, non-Hispanic, and below poverty level were greater than in areas in which white, non-Hispanic primary care physicians practiced. These findings argue for special provision to admit ethnic minorities to undergraduate and graduate medical education programs.
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Affiliation(s)
- G E Fryer
- University of Colorado Health Sciences Center, USA
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Wofford MR, Anderson DC, Brown CA, Jones DW, Miller ME, Hall JE. Antihypertensive effect of alpha- and beta-adrenergic blockade in obese and lean hypertensive subjects. Am J Hypertens 2001; 14:694-8. [PMID: 11465655 DOI: 10.1016/s0895-7061(01)01293-6] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
The purpose of this study was to determine the contribution of the adrenergic system in mediating hypertension in obese and lean patients. Thirteen obese, hypertensive patients with a body mass index (BMI) > or =28 kg/m2 (obese) and nine lean patients with a BMI < or =25 kg/m2 (lean) were recruited. After a 1-week washout period, participants underwent daytime ambulatory blood pressure monitoring (ABPM). Participants were then treated with the alpha-adrenergic antagonist doxazosin, titrating to 4 mg QHS in 1 week. In the next week, the beta-adrenergic antagonist atenolol was added at an initial dose of 25 mg/day and titrated to 50 mg/day within 1 week. One month after the addition of atenolol, all patients underwent a second ABPM session. There were no differences between the obese and lean subjects in baseline systolic (SBP), diastolic (DBP), or mean arterial pressures (MAP) measured by office recording or ABPM. However, obese subjects had higher heart rates than lean subjects (87.5+/-2.4 v 76.8+/-4.9 beats/min). After 1 month of treatment with the adrenergic blockers, obese patients had a significantly lower SBP (130.0+/-2.5 v 138.9+/-2.1 mm Hg, P = .02) and MAP (99.6+/-2.3 v 107.0+/-1.5 mm Hg, P = .02) than lean patients. Obese patients also tended to have a lower DBP than lean patients (84.3+/-2.5 v 90.9+/-1.6 mm Hg, P = .057), but there was no significant difference in heart rate after 1 month of adrenergic blockade. These results indicate that blood pressure is more sensitive to adrenergic blockade in obese than in lean hypertensive patients and suggest that increased sympathetic activity may be an important factor in the maintenance of hypertension in obesity.
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Affiliation(s)
- M R Wofford
- Department of Medicine, University of Mississippi Medical Center, Jackson 39216-4505, USA.
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Jones RA, Ricard R, Sefcik E, Miller ME. The health risk of hypertension in south Texas: a demographic profile. Holist Nurs Pract 2001; 15:35-44. [PMID: 12120493 DOI: 10.1097/00004650-200107000-00007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This article provides a demographic profile of the hypertensive adult in South Texas. Hypertension, a silent disease because of its lack of overt signs and symptoms, poses a major public health problem. Few prevalence studies have been completed reflecting Mexican-American populations. South Texas hypertension trends are comparable to national trends. However, the awareness of hypertension in South Texas is lower than that of the national population. The density of risk factors may be responsible for the patterns of South Texas hypertension.
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Affiliation(s)
- R A Jones
- School of Nursing and Health Sciences, Texas A&M University-Corpus Christi, Corpus Christi, Texas, USA
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Jadelis K, Miller ME, Ettinger WH, Messier SP. Strength, balance, and the modifying effects of obesity and knee pain: results from the Observational Arthritis Study in Seniors (oasis). J Am Geriatr Soc 2001; 49:884-91. [PMID: 11527479 DOI: 10.1046/j.1532-5415.2001.49178.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To examine the relationship between muscular strength and dynamic balance in a sample of older adults with knee pain and to determine the role that obesity and severity of knee pain play in the ability to maintain balance. DESIGN Cross-sectional study designed to examine the association between strength and balance in a cohort of older adults with chronic knee pain. SETTING A university health and exercise science center. PARTICIPANTS A cohort of 480 adults age 65 and older with knee pain. MEASUREMENTS Force platform dynamic balance measure of the center of pressure excursion during a forward and subsequent backward lean. Isokinetic strength measures of concentric and eccentric knee flexion and extension and concentric ankle plantar flexion and dorsiflexion. Body mass index (BMI) and a knee pain scale were used to measure obesity and knee pain, respectively. RESULTS A regression model was developed to investigate the relationship between dynamic balance and muscular strength while controlling for gender, BMI, radiographic severity, knee pain, and foot length. Knee strength alone explained 18.4% of the variability in dynamic balance. The addition of knee pain, BMI, radiographic severity, gender, and foot length explained an additional 6.7%. When the knee-ankle interaction, ankle strength, and knee strength--pain interaction variables were added to the regression model, 28.9% of the variability in dynamic balance was explained. CONCLUSIONS Strength appears to play a significant role in maintaining balance in an older, osteoarthritic population. We found that mean knee strength accounted for approximately 19% of the variability in dynamic balance. Hence, greater knee strength was associated with better dynamic balance. The best dynamic balance performances occurred in participants that had a combination of strong knees and strong ankles. However, knee osteoarthritic patients with weak knee strength could still maintain high levels of dynamic balance by having strong ankle strength. Moreover, we have shown that obesity is associated with attenuated dynamic balance performance and that poorer balance is associated with higher pain scores in the presence of weaker knees. For stronger knees, however, pain does not appear to be related to balance.
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Affiliation(s)
- K Jadelis
- J.B. Snow Biomechanics Laboratory, Department of Health and Exercise Science, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27109, USA
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Abstract
Cyclin-dependent kinase (CDK) activity is essential for eukaryotic cell cycle events. Multiple cyclins activate CDKs in all eukaryotes, but it is unclear whether multiple cyclins are really required for cell cycle progression. It has been argued that cyclins may predominantly act as simple enzymatic activators of CDKs; in opposition to this idea, it has been argued that cyclins might target the activated CDK to particular substrates or inhibitors. Such targeting might occur through a combination of factors, including temporal expression, protein associations, and subcellular localization.
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Affiliation(s)
- M E Miller
- The Rockefeller University, New York, NY 10021, USA
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45
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Breysse PN, Lees PS, Rooney BC, McArthur BR, Miller ME, Robbins C. End-user exposures to synthetic vitreous fibers: II. Fabrication and installation fabrication of commercial products. Appl Occup Environ Hyg 2001; 16:464-70. [PMID: 11318389 DOI: 10.1080/10473220117198] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This article summarizes the results of exposure monitoring conducted during the installation and fabrication of commercial synthetic vitreous fiber (SVF) products. Included in this investigation were fiberglass duct insulation and construction applications (duct board, duct liner, and duct wrap), pipe and vessel insulation, batt insulation for prefabricated homes, and general fiberglass products. Commercial mineral wool products sampled as a part of this investigation included ceiling tiles, building safing, and loose insulation for prefabricated homes. A total of 520 valid air samples were collected as a part of this investigation and were analyzed using gravimetric, phase contrast microscopy (PCM), or scanning electron microscopy (SEM). Airborne fiber-size distributions were also determined for a subset of samples collected for SEM analysis. As a result of the task-based sampling strategy used in this study, sample times reflect exposures over the time the person was actually engaged in SVF-related work activities, and exposure results are therefore presented as task-length averages (TLAs). Thirty-five total dust samples were collected as a part of this investigation, resulting in 14 TLAs ranging from 0.3 to 7.6 mg/m3. A total of 125 PCM-based TLAs were collected, with the mean TLA time for all product and occupation categories ranging from 277 to 443 minutes. The mean PCM-based TLAs for all product/occupations were below 1.0 f/cm3, ranging from 0.04 to 0.68 f/cm3. A total of 116 SEM TLAs were determined. Average SEM-based TLA concentrations were slightly lower than the PCM-based estimates and ranged from <0.01 to 0.16 f/cm3. The geometric mean fiber diameters for commercial products and occupations sampled as a part of the investigation ranged from 0.8 microm to 1.9 microm. Geometric mean fiber length varied by a factor of approximately three, ranging from 9.5 microm to 29.5 microm.
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Affiliation(s)
- P N Breysse
- School of Hygiene and Public Health, Johns Hopkins University, Baltimore, Maryland, USA
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46
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Abstract
The objectives of this study include conducting an analysis of access to primary medical care in rural Colorado through simultaneous consideration of primary care physician-to-population and distance-to-nearest provider indices. Analyses examined the potential development and implications of excessively large, perhaps unmanageable patient caseloads that might result from every rural Coloradoan's exclusive use of the nearest generalist physician as a regular source of care. Using American Medical Association Physician Masterfile data for 1995 and coordinates for latitude and longitude from U.S. Census files (Census of Population and Housing, 1990), the authors calculated distance to the nearest primary care physician for residents of each of the 1,317 block groups in Colorado's 52 rural counties. Caseloads for each generalist physician were computed assuming the population used the nearest provider for care. Straight-line mileage to primary medical care was modest for rural Coloradoans--a median distance of 2.5 miles. Almost two-thirds (65 percent) of the population resided within 5 miles, and virtually all residents (99 percent) were within 30 miles of a generalist physician. However, had everyone traveled the shortest possible distance to care, demand for service from many of the 343 primary care doctors in rural regions of the state would have been overwhelming. The results of simultaneous application of distance-to-care and provider-to-population techniques unrestricted by geographic boundaries depict access to primary medical care and corresponding consumer difficulty more fully than in previous studies. Further combination of methods of needs assessment such as those used in this analysis may better inform the future efforts of organizations mandated to address health care underservice in rural areas.
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Affiliation(s)
- G E Fryer
- University of Colorado Health Sciences Center, Denver 80220, USA
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47
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Rejeski WJ, Martin KA, Miller ME, Ettinger WH, Rapp S. Perceived importance and satisfaction with physical function in patients with knee osteoarthritis. Ann Behav Med 2001; 20:141-8. [PMID: 9989320 DOI: 10.1007/bf02884460] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
This investigation examined the determinants of satisfaction with physical function for participants in an Observational Arthritis Study in Seniors (OASIS). The sample consisted of 480 men (51%) and women (49%) over the age of 65 years who had difficulty performing activities of daily living due to knee pain. As part of baseline testing for OASIS, participants completed a measure that assessed satisfaction with function for six physical activities. After controlling for relevant covariates, scores on the satisfaction index were regressed on seven conceptually relevant predictor variables. The results revealed that satisfaction with physical function is a distinct construct from level of function, irrespective of whether the latter variable is measured objectively or subjectively. When entered into a hierarchical regression model, 6-minute walk test data accounted for 11% of the variance in satisfaction scores, whereas perceived difficulty accounted for an additional 22%. Moreover, a significant interaction term between importance and perceived difficulty revealed that patients who rated the activities as important and who had high levels of perceived difficulty had the lowest satisfaction scores. Discussion focuses on the determinants of satisfaction with physical function with emphasis on the interaction between perceived difficulty and importance.
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Affiliation(s)
- W J Rejeski
- Department of Health and Exercise Science, Wake Forest University, Winston-Salem, NC 27109, USA
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Cummins TM, Robbins GA, Henebry BJ, Goad CR, Gilbert EJ, Miller ME, Stuart JD. A water extraction, static headspace sampling, gas chromatographic method to determine MTBE in heating oil and diesel fuel. Environ Sci Technol 2001; 35:1202-1208. [PMID: 11347934 DOI: 10.1021/es001355l] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A method was developed to determine the fuel/water partition coefficient (KMTBE) of methyl tert-butyl ether (MTBE) and then used to determine low parts per million concentrations of MTBE in samples of heating oil and diesel fuel. A special capillary column designed for the separation of MTBE and to prevent coelution and a gas chromatograph equipped with a photoionization detector (PID) were used. MTBE was partitioned from fuel samples into water during an equilibration step. The water samples were then analyzed for MTBE using static headspace sampling followed by GC/PID. A mathematical relationship was derived that allowed a KMTBE value to be calculated by utilizing the fuel/water volume ratios and the corresponding PID signal. KMTBE values were found to range linearly from 3.8 to 10.9 over a temperature range of 5-40 degrees C. This analysis method gave a MDL of 0.7 ppm MTBE in the fuel and a relative average accuracy of +/-15% by comparison with an independent laboratory using purge and trap GC/ MS analysis. MTBE was found in home heating oil in residential tanks and in diesel fuel at service stations throughout the state of Connecticut. The levels of MTBE were found to vary significantly with time. Heating oil and diesel fuel from terminals were also found to contain MTBE. This research suggests thatthe reported widespread contamination of groundwater with MTBE may also be due to heating oil and diesel fuel releases to the environment. used extensively for the past 20 years as a gasoline additive (up to 15 wt %) to reduce automobile carbon monoxide and hydrocarbon emissions. The fact that MTBE is highly soluble in water (approximately 5 wt %) (3) and chemically inert when compared to other fuel constituents causes it to be often detected at high concentrations in groundwater in the vicinity of gasoline spills. The EPA has reported that low levels of MTBE in drinking water (above 40 microg/L) may cause unpleasant taste and odors and has designated MTBE as a possible human carcinogen (4). Past studies have concentrated on the reporting of MTBE levels in groundwater near gasoline spills. Happel et al. reported an MTBE occurrence rate of approximately 78% at locations where hydrocarbons have impacted groundwater (5). Johnson et al. estimate that 9,000 leaking underground fuel tanks have caused MTBE contamination at community water supplies in the 31 states surveyed (excluding California and Texas) (6). Robbins et al. reported finding a significant number of MTBE detections in groundwater samples taken at sites in Connecticut known to be contaminated by heating oil spills (7). Later, this same research group reported finding MTBE contamination to range from 9.7 to 906 mg/L in heating oil and from 74 to 120 mg/L in diesel fuel in samples collected from storage tanks in Connecticut (8). The method used to analyze these samples was based on fuel-water partitioning and GC analysis. This present study provides the detailed basis for that analytical method. MTBE fuel-water partition coefficients as a function of temperature, which are critical to the method, are also presented. This study also reports on variations in MTBE levels as a function of time observed at several residences and a service station. Analytical results are reported for samples taken from terminals as part of an effort to assess the sources of MTBE in heating oil and diesel fuel.
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Affiliation(s)
- T M Cummins
- Department of Chemistry, University of Connecticut, Storrs 06269-3060, USA
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Abstract
This report documents the clinicopathological features in two Jamaican children who presented with infective dermatitis, glomerulonephritis, renal failure and human T-cell lymphotropic virus (HTLV-1) seropositivity. Severe hypertension with hypertensive encephalopathy was the most impressive clinical feature. Histological findings from renal biopsy specimens in both cases revealed significant glomerulosclerosis with fibrosis, chronic inflammatory cell infiltrates in the interstitium, and arteriolar hypertensive changes. Membranoproliferative glomerulonephritis (MPGN) was demonstrable in case 1 and marked focal glomerulosclerosis in case 2. Case 1 developed end stage renal failure and died within 3 years of diagnosis. Case 2 remains hypertensive and in chronic renal failure. Although a causal relationship between HTLV-1 infection and renal disease cannot be proven by these two cases, it appears that renal involvement in children with HTLV-1 infection is severe, with the potential for chronic renal failure and malignant hypertension. HTLV-1 nephropathy should be suspected in children with infective dermatitis and renal disease.
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Affiliation(s)
- M E Miller
- Section of Child Health, University of the West Indies, Mona, Kingston 7, Jamaica, West Indies.
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Abstract
OBJECTIVES To explore initially how low levels of physical activity influence lower body functional limitations in participants of the Longitudinal Study of Aging. Changes in functional limitations are used subsequently to predict transitions in the activities of daily living/instrumental activities of daily living (ADL/IADL) disability, thus investigating a potential pathway for how physical activity may delay the onset of ADL/IADL disability and, thus, prolong independent living. DESIGN Analysis of a complex sample survey of US civilian, noninstitutionalized population aged 70 years and older in 1984, with repeated interviews in 1986, 1988, and 1990. SETTING AND PARTICIPANTS Analyses concentrated on 5151 men and women targeted for interview at all four LSOA interviews. MEASUREMENTS Characteristics used in analyses: gender, age, level of physical activity, comorbid conditions including the presence of hypertension, diabetes, arthritis, and atherosclerotic heart disease, levels of functional limitations, and ADL/IADL disability. RESULTS Transitional models provide evidence that older adults who have varying levels of disability and who report at least a minimal level of physical activity experience a slower progression in functional limitations (OR = .45, P < .001 for severe vs less severe limitations). This low level of physical activity, through its influence on changes in functional limitations, is shown to slow the progression of ADL/IADL disability. CONCLUSIONS Results from analyses provide supporting evidence that functional limitations can mediate the effect that physical activity has on ADL/IADL disability. These results contribute further to the increasing data that seem to suggest that physical activity can reduce the progression of disability in older adults.
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Affiliation(s)
- M E Miller
- Department of Public Health Sciences, Wake Forest University, Winston-Salem, North Carolina 27157, USA
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