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Wigman B, Popov S, Bagdasarian AL, Shao B, Benton TR, Williams CG, Fisher SP, Lavallo V, Houk KN, Nelson HM. Vinyl Carbocations Generated under Basic Conditions and Their Intramolecular C-H Insertion Reactions. J Am Chem Soc 2019; 141:9140-9144. [PMID: 31082208 DOI: 10.1021/jacs.9b02110] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Here we report the surprising discovery that high-energy vinyl carbocations can be generated under strongly basic conditions, and that they engage in intramolecular sp3 C-H insertion reactions through the catalysis of weakly coordinating anion salts. This approach relies on the unconventional combination of lithium hexamethyldisilazide base and the commercially available catalyst, triphenylmethylium tetrakis(pentafluorophenyl)borate. These reagents form a catalytically active lithium species that enables the application of vinyl cation C-H insertion reactions to heteroatom-containing substrates.
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Affiliation(s)
- Benjamin Wigman
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Stasik Popov
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Alex L Bagdasarian
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Brian Shao
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Tyler R Benton
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Chloé G Williams
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Steven P Fisher
- Department of Chemistry , University of California , Riverside , California 92521 , United States
| | - Vincent Lavallo
- Department of Chemistry , University of California , Riverside , California 92521 , United States
| | - K N Houk
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
| | - Hosea M Nelson
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
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Vacala TL, Carlson PR, Arreola-Hester A, Williams CG, Makhoul EW, Vadola PA. Gold-Catalyzed Dearomative Spirocyclization of N-Aryl Alkynamides for the Synthesis of Spirolactams. J Org Chem 2018; 83:1493-1501. [PMID: 29308642 DOI: 10.1021/acs.joc.7b03125] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Taylor L. Vacala
- Department of Chemistry, DePaul University, 1110 West Belden Avenue, Chicago, Illinois 60614, United States
| | - Paul R. Carlson
- Department of Chemistry, DePaul University, 1110 West Belden Avenue, Chicago, Illinois 60614, United States
| | - Asa Arreola-Hester
- Department of Chemistry, DePaul University, 1110 West Belden Avenue, Chicago, Illinois 60614, United States
| | - Chloé G. Williams
- Department of Chemistry, DePaul University, 1110 West Belden Avenue, Chicago, Illinois 60614, United States
| | - Evana W. Makhoul
- Department of Chemistry, DePaul University, 1110 West Belden Avenue, Chicago, Illinois 60614, United States
| | - Paul A. Vadola
- Department of Chemistry, DePaul University, 1110 West Belden Avenue, Chicago, Illinois 60614, United States
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Vacala T, Bejcek LP, Williams CG, Williamson AC, Vadola PA. Gold-Catalyzed Hydroarylation of N-Aryl Alkynamides for the Synthesis of 2-Quinolinones. J Org Chem 2017; 82:2558-2569. [PMID: 28169539 DOI: 10.1021/acs.joc.6b02984] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A mild method for the synthesis of 2-quinolinones via hydroarylation of N-aryl alkynamides is reported. While traditional methods have relied on the use of strong Brønsted or Lewis acids, this report describes the development of mild reaction conditions that yield 2-quinolinones in good to excellent yield using a commercially available gold catalyst. Substrates bearing a variety of functional groups are presented, with N-substitution proving to be key to the reactivity of several substrates.
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Affiliation(s)
- Taylor Vacala
- Department of Chemistry, DePaul University , 1110 West Belden Avenue, Chicago, Illinois 60614, United States
| | - Lauren P Bejcek
- Department of Chemistry, DePaul University , 1110 West Belden Avenue, Chicago, Illinois 60614, United States
| | - Chloé G Williams
- Department of Chemistry, DePaul University , 1110 West Belden Avenue, Chicago, Illinois 60614, United States
| | - Alexandra C Williamson
- Department of Chemistry, DePaul University , 1110 West Belden Avenue, Chicago, Illinois 60614, United States
| | - Paul A Vadola
- Department of Chemistry, DePaul University , 1110 West Belden Avenue, Chicago, Illinois 60614, United States
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González-Martínez SC, Robledo-Arnuncio JJ, Collada C, Díaz A, Williams CG, Alía R, Cervera MT. Cross-amplification and sequence variation of microsatellite loci in Eurasian hard pines. Theor Appl Genet 2004; 109:1125-32. [PMID: 14985972 DOI: 10.1007/s00122-004-1739-0] [Citation(s) in RCA: 19] [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] [Received: 06/11/2003] [Accepted: 01/05/2004] [Indexed: 05/20/2023]
Abstract
Microsatellite transfer across coniferous species is a valued methodology because de novo development for each species is costly and there are many species with only a limited commodity value. Cross-species amplification of orthologous microsatellite regions provides valuable information on mutational and evolutionary processes affecting these loci. We tested 19 nuclear microsatellite markers from Pinus taeda L. (subsection Australes) and three from P. sylvestris L. (subsection Pinus) on seven Eurasian hard pine species ( P. uncinata Ram., P. sylvestris L., P. nigra Arn., P. pinaster Ait., P. halepensis Mill., P. pinea L. and P. canariensis Sm.). Transfer rates to species in subsection Pinus (36-59%) were slightly higher than those to subsections Pineae and Pinaster (32-45%). Half of the trans-specific microsatellites were found to be polymorphic over evolutionary times of approximately 100 million years (ten million generations). Sequencing of three trans-specific microsatellites showed conserved repeat and flanking regions. Both a decrease in the number of perfect repeats in the non-focal species and a polarity for mutation, the latter defined as a higher substitution rate in the flanking sequence regions close to the repeat motifs, were observed in the trans-specific microsatellites. The transfer of microsatellites among hard pine species proved to be useful for obtaining highly polymorphic markers in a wide range of species, thereby providing new tools for population and quantitative genetic studies.
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González-Martínez SC, Robledo-Arnuncio JJ, Collada C, Díaz A, Williams CG, Alía R, Cervera MT. Cross-amplification and sequence variation of microsatellite loci in Eurasian hard pines. Theor Appl Genet 2004; 109:103-11. [PMID: 14985972 DOI: 10.1007/s00122-004-1596-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2003] [Accepted: 01/05/2004] [Indexed: 05/23/2023]
Abstract
Microsatellite transfer across coniferous species is a valued methodology because de novo development for each species is costly and there are many species with only a limited commodity value. Cross-species amplification of orthologous microsatellite regions provides valuable information on mutational and evolutionary processes affecting these loci. We tested 19 nuclear microsatellite markers from Pinus taeda L. (subsection Australes) and three from P. sylvestris L. (subsection Pinus) on seven Eurasian hard pine species ( P. uncinata Ram., P. sylvestris L., P. nigra Arn., P. pinaster Ait., P. halepensis Mill., P. pinea L. and P. canariensis Sm.). Transfer rates to species in subsection Pinus (36-59%) were slightly higher than those to subsections Pineae and Pinaster (32-45%). Half of the trans-specific microsatellites were found to be polymorphic over evolutionary times of approximately 100 million years (ten million generations). Sequencing of three trans-specific microsatellites showed conserved repeat and flanking regions. Both a decrease in the number of perfect repeats in the non-focal species and a polarity for mutation, the latter defined as a higher substitution rate in the flanking sequence regions close to the repeat motifs, were observed in the trans-specific microsatellites. The transfer of microsatellites among hard pine species proved to be useful for obtaining highly polymorphic markers in a wide range of species, thereby providing new tools for population and quantitative genetic studies.
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Abstract
In pines, self-pollination rates can be as high as 34% yet only 5% of viable seed is a product of self-fertilization. This decline in selfed seed viability is the consequence of post-fertilization exclusion mechanisms operating via the embryo lethal system. Recent molecular marker dissection studies suggest that the embryo lethal system is composed of semilethal factors dispersed across the genome, but it is not clear whether overdominant lethal factors are rare or representative. The study objective was to determine if overdominance was rare for the embryo lethal system in conifers. Three cohorts of selfed offspring from a single Pinus taeda parent were genotyped for nuclear microsatellites. Maximum likelihood tests based on distorted segregation ratios for single markers and for interval mapping were used to infer the degree of dominance. Four hypotheses about overdominance lethal factors were tested: (1) overdominant lethal factors rarely occur within the embryo lethal system, (2) overdominant lethal factors are rarely detected because they are transient and display stage-specific expression, (3) overdominant lethal factors are rarely detected due to tight linkage with rare marker alleles and (4) dominance estimation is unbiased by gametic selection. Four out of the seven chromosomal segments were linked to an overdominant lethal factor. One of these four segments had symmetric overdominance, an effect which persisted from embryo maturity through germination. Four overdominant lethal factors were linked to common and rare marker alleles. Gametic selection was not a source of bias in dominance estimation. Overdominant or pseudo-overdominant lethal factors are a common component of the conifer embryo lethal system.
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Affiliation(s)
- C G Williams
- Graduate Genetics Program, Texas A&M University, 305 Horticulture Building, TAMU 2135, College Station, TX 77843-2135, USA.
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Kim TK, Sharma B, Williams CG, Ruffner MA, Malik A, McFarland EG, Elisseeff JH. Experimental model for cartilage tissue engineering to regenerate the zonal organization of articular cartilage. Osteoarthritis Cartilage 2003; 11:653-64. [PMID: 12954236 DOI: 10.1016/s1063-4584(03)00120-1] [Citation(s) in RCA: 195] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Regeneration of the zonal organization of articular cartilage may be an important advancement for cartilage tissue engineering. The first goal of this study was to validate our surgical technique as a method to selectively isolate chondrocytes from different zones of bovine articular cartilage. The second goal was to confirm that chondrocytes from different zones would have different proliferative and metabolic activities in two-dimensional (2-D) and 3-D cultures. Finally, to regenerate the zonal organization, we sought to make multi-layered constructs by encapsulating chondrocytes from different zones of articular cartilage. DESIGN Cartilage slices were removed from three (upper, middle, and lower) zones of articular cartilage of young bovine legs. Histology and biochemical composition of the cartilage slices were analyzed to confirm that they had been obtained from the proper zone. Growth kinetics and gene expression in monolayer culture and matrix formation in photopolymerizing hydrogels were evaluated. Multi-layered photopolymerizing hydrogels were constructed with chondrocytes from each zone of native cartilage encapsulated. Cell viability and maintenance of the cells in the respective layer were evaluated using the Live/Dead Viability kit and cell tracking protocols, respectively. After 3 weeks, the multi-layered constructs were harvested for histologic examination including immunohistochemistry for type II collagen. RESULTS Analysis of histology and biochemical composition confirmed that the cartilage slices had been obtained from the specific zone. Chondrocytes from different zones differed in growth kinetics and gene expression in monolayer and in matrix synthesis in 3-D culture. Cells encapsulated in each of the three layers of the hydrogel remained viable and remained in the respective layer in which they were encapsulated. After 3-week culture, each zone of multi-layered constructs had similar histologic findings to that of native articular cartilage. CONCLUSION We present this as an experimental model to regenerate zonal organization of articular cartilage by encapsulating chondrocytes from different layers in multi-layered photopolymerizing gels.
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Affiliation(s)
- T-K Kim
- Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA
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Abstract
Developing microsatellites from the large, highly duplicated conifer genome requires special tools. To improve the efficiency of developing Pinus taeda L. microsatellites, undermethylated (UM) DNA fragments were used to construct a microsatellite-enriched copy library. A methylation-sensitive restriction enzyme, McrBC, was used to enrich for UM DNA before library construction. Digested DNA fragments larger than 9 kb were then excised and digested with RsaI and used to construct nine dinucleotide and trinucleotide libraries. A total of 1016 microsatellite-positive clones were detected among 11 904 clones and 620 of these were unique. Of 245 primer sets that produced a PCR product, 113 could be developed as UM microsatellite markers and 70 were polymorphic. Inheritance and marker informativeness were tested for a random sample of 36 polymorphic markers using a three-generation outbred pedigree. Thirty-one microsatellites (86%) had single-locus inheritance despite the highly duplicated nature of the P. taeda genome. Nineteen UM microsatellites had highly informative intercross mating type configurations. Allele number and frequency were estimated for eleven UM microsatellites using a population survey. Allele numbers for these UM microsatellites ranged from 3 to 12 with an average of 5.7 alleles/locus. Frequencies for the 63 alleles were mostly in the low-common range; only 14 of the 63 were in the rare allele (q < 0.05) class. Enriching for UM DNA was an efficient method for developing polymorphic microsatellites from a large plant genome.
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Affiliation(s)
- Y Zhou
- Genetics Program and Department of Forest Science, Texas A&M University, College Station 77843-2135, USA
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Abstract
Prefertilization mechanisms influencing selfing rates are thought to be absent in conifers. Outcrossing in conifers is promoted via an embryo-lethal system, but the genetic mechanism is poorly understood. This study is the first experimental profile of the genetic mechanism promoting outcrossing in conifers. Molecular dissection of a Pinus taeda L. selfed pedigree detected a chromosomal region identified as PtTX3020-RPtest9. Within this region, a semilethal factor was tightly linked (r = 0.0076) to a polymorphic expressed sequence tag (EST). The linkage group flanking the lethal factor showed strong heterozygote advantage. Using genotypic frequencies for the linkage group, three hypotheses about the semilethal factor could be tested: (1) the presence of a balanced lethal system, i.e., a lethal factor present in each of the two marker intervals; (2) gametic selection operative prior to fertilization; and (3) a stage-specific lethal factor. Selection acted via the embryo-lethal system. No support for a genetic mechanism operating prior to fertilization was found. The semilethal factor exerted no effect after embryo maturity. The genetic mechanism promoting outcrossing in P. taeda L. appears to have a balancing selection system due to either pseudo-overdominance or true overdominance.
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Affiliation(s)
- C G Williams
- Graduate Genetics Program, Texas A&M University, College Station Texas 77843-2135, USA.
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Abstract
Vascular plant species have shown a low level of microsatellite conservation compared to many animal species. Finding trans-specific microsatellites for plants may be improved by using a priori knowledge of genome organization. Fifteen triplet-repeat microsatellites from hard pine (Pinus taeda L.) were tested for trans-specific amplification across seven hard pines (P. palustris Mill., P. echinata Mill., P. radiata D. Don., P. patula Schiede et Deppe, P. halepensis Mill., P. kesiya Royle), a soft pine (P. strobus L.), and Picea rubens Sargent. Seven of 15 microsatellites had trans-specific amplification in both hard and soft pine subgenera. Two P. taeda microsatellites had conserved flanking regions and repeat motifs in all seven hard pines, soft pine P. strobus, and P. rubens. Perfect triplet-repeat P. taeda microsatellites appear to be better candidates for trans-specific polymorphism than compound microsatellites. Not all perfect triplet-repeat microsatellites were conserved, but all conserved microsatellites had perfect repeat motifs. Persistent microsatellites PtTX2123 and PtTX3020 had highly conserved flanking regions and a conserved repeat motif composition with variable repeat unit numbers. Using trinucleotide microsatellites improved trans-specific microsatellite recovery among hard and soft pine species.
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Affiliation(s)
- B L Kutil
- Graduate Genetics Program, Texas A&M University, College Station, Texas 77843-2135, USA
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Abstract
Microsatellite clustering may account for genetic maps which do not coalesce into the expected number of linkage groups. Microsatellite organization within the large genome of Pinus taeda (1C = 20,000 Mb) was determined by (1) testing whether repeat motifs were sequestered within the low-copy DNA kinetic component and (2) testing for repeat motif clusters within DNA fragments regardless of copy number. Within the low-copy kinetic component, either (AC)n or (AG)n repeat units were present in 32% of sequences. No repeat motifs were found in the total genome control. Clustered repeat motifs were frequent; the (ATG)n triplet repeat motif was located upstream from a CG-rich trinucleotide microsatellite in 26 out of 44 microsatellite sequences. Fourteen of the clustered (ATG)n sequences could be assembled into four microsatellite sequence families based on similarities in the flanking regions. Consistent with the DNA turnover model, family members shared similar flanking regions but differed in repeat motif composition and length.
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Affiliation(s)
- C G Elsik
- Texas A and M University, Graduate Genetics Program, College Station 77843, USA
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12
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Abstract
Excess DNA in the single-copy component is rarely recognized as a contributor to the C-value paradox yet the single-copy component of the pine genome is reported to comprise over 3000 Mb of DNA, in large excess over the estimated 100 Mb required for gene expression. Two hypotheses regarding the factors that might contribute to the excess low-copy-number DNA were tested. The first hypothesis proposes that the excess low-copy kinetic component is actually overestimated by reassociation data analysis. To test this, a previously published C0t curve for Pinus strobus was reanalyzed using a new estimate of genome size based on laser flow cytometry. Part of the excess low-copy-number DNA in the pine genome could be attributed to the choice of parameters used in the analysis of the reassociation data. The second hypothesis holds that diverged retrotransposons contribute to the excess low-copy DNA. Sequences randomly sampled from single-copy and low-repetitive kinetic components of the P. taeda genome were characterized. Twelve of 46 fragments cloned from these fractions were found to show sequence similarity to retroelements: hence diverged retroelements contribute to the excess low-repetitive kinetic component in the pine genome. Similarity search was shown to be a conservative method for identifying retroelements, and thus the number of retroelements in the low-copy component was actually underestimated. Most of the retroelements in this fraction were nonfunctional. divergent from known retroelement families and previously reported only for flowering plants. Divergent retrotransposons are thus a major factor contributing to the expansion of the low-repetitive DNA component in higher plants.
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Affiliation(s)
- C G Elsik
- Graduate Genetics Program, Texas A and M University, College Station 77843-2135, USA
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Elsik CG, Minihan VT, Hall SE, Scarpa AM, Williams CG. Low-copy microsatellite markers for Pinus taeda L. Genome 2000; 43:550-5. [PMID: 10902720] [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: 02/17/2023]
Abstract
Eighteen low-copy and genomic microsatellite markers were tested for Mendelian inheritance and then assayed in 41 Pinus taeda L. samples drawn from five regions in the southern United States. The PCR products had multiple alleles, high levels of polymorphism, and little non-specific priming. Fifteen of the 18 markers were informative for a P. taeda three-generation RFLP (restriction fragment length polymorphism) pedigree, and a P. taeda population survey revealed three to 28 alleles per locus. The highest allele numbers and polymorphic information content (PIC) values were associated with complex repeat sequences and (or) with sequences consisting of the longer strings of perfect repeats. The abundance of low- to rare-frequency alleles also accounted for high PIC values in both types of markers. Low-copy microsatellites are useful for the large, complex pine genome, especially in the absence of entire gene sequences in public databases and with the low levels of polymorphism in markers developed from expressed sequence tags (ESTs).
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Affiliation(s)
- C G Elsik
- Graduate Genetics Program, Texas A&M University, College Station 77843-2135, USA
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Nauta HJ, Soukup VM, Fabian RH, Lin JT, Grady JJ, Williams CG, Campbell GA, Westlund KN, Willis WD. Punctate midline myelotomy for the relief of visceral cancer pain. J Neurosurg 2000; 92:125-30. [PMID: 10763680 DOI: 10.3171/spi.2000.92.2.0125] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [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: 11/06/2022]
Abstract
OBJECT This study offers clinical support for the concept that neurosurgical interruption of a midline posterior column pathway by performing a punctate midline myelotomy (PMM) provides significant pain relief without causing adverse neurological sequelae in cancer patients with visceral pain refractory to other therapies. METHODS A PMM of the posterior columns was performed in six cancer patients in whom visceral pain had been refractory to other therapies. The cause of the visceral pain was related to residual, progressive, or recurrent local cancer or postirradiation effects. Clinical efficacy of the procedure was examined by comparing patient pain ratings and narcotic usage pre- and post-PMM. Follow-up periods ranged from 3 to 31 months. Examination of the results indicates a significant reduction in pain ratings as well as a significant reduction in daily narcotic use. No adverse neurological effects were observed. One spinal cord has been recovered for postmortem examination. CONCLUSIONS These findings provide corroborating clinical evidence for the existence of a newly recognized midline posterior column pathway that mediates the perception of visceral pelvic and abdominal pain. Preliminary data indicate that significant pain relief can be obtained following PMM with minimal neurological morbidity and suggest that the procedure may provide an alternative treatment modality for cancer-related pain in patients in whom adequate pain control with narcotics cannot be achieved or narcotic side effects cannot be tolerated.
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Affiliation(s)
- H J Nauta
- Department of Neurology, University of Texas Medical Branch, Galveston 77555-0517, USA.
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Abstract
Deducing the origin of early 20th century introductions of Pinus taeda into Zimbabwe is possible given microsatellite markers and clear population differentiation in ancestral U.S. populations. This study was designed to determine whether P. taeda introductions into Zimbabwe came from one U.S. region or whether the present-day population is an admixture of introductions from east and west of the Mississippi River Valley. Principal components analysis, Cavalli-Sforza and Edwards' chord distances and presence of diagnostic alleles each indicate that the Zimbabwe population is an admixture. There were five novel alleles in the Zimbabwe population not represented in the indigenous U.S. populations, possibly because of de novo mutation, introgression with other introduced North American pines or sampling error.
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Affiliation(s)
- C G Williams
- Faculty of Genetics, Texas A & M University, College Station, Texas 77843-2135, USA.
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Williams CG. Poliomyelitis: extinct by year 2000--but not over. AAOHN J 2000; 48:25-31. [PMID: 15635917] [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: 05/01/2023]
Abstract
This is a comparative analysis of findings from a sample of individuals who had poliomyelitis with findings from seminal works on post polio syndrome. The sample included 148 individuals who developed poliomyelitis earlier in life. The findings are compared with the seminal studies of Halstead (1985a, 1985b). Seventy-two percent of the sample were experiencing post polio syndrome, defined as having progressive fatigue and one other symptom of sequelae to a moderate or severe degree. The mean age of the sample was 54. The majority of subjects had some college education, were married, belonged to support groups, and were employed. The mean age for contracting polio was 10.5, with a mean of 3.8 years to maximum recovery. At onset of the initial illness, 121 subjects were hospitalized. The period of stability from the point of maximum recovery to onset of sequelae had a mean of 29.8 years. Fatigue and muscle weakness at onset were predictive for developing sequelae. Subjects' lifestyle changes are reported. Implications focus on workplace issues. This study supports and extends the findings of the seminal works.
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Affiliation(s)
- C G Williams
- Eastern Kentucky University, Department of Baccalaureate and Graduate Nursing, Richmond, KY, USA
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Abstract
Maize meiotic mutant desynaptic (dy) was tested as a candidate recombination modifier gene because its effect is manifested in prophase I. Recombination rates for desynaptic (dy) and its wild type were compared in two ways: (1) segregation analysis using six linked molecular markers on chromosome 1L and (2) cytogenetic analysis using fluorescence in situ hybridization (FISH)-aided meiotic configurations observed in metaphase I. Chromosome 1L map lengths among the six linked markers were 45-63 cM for five F2 dy/dy plants, significantly lower than the wild-type F2 map distance of 72 cM. Chromosomes 2 and 6 were marked with rDNA FISH probes, and their map lengths were estimated from FISH-adorned meiotic configurations using the expectation-maximization algorithm. Chiasma frequencies for dy/dy plants were significantly reduced for both arms of chromosome 2, for chromosome arm 6L, and for eight unidentified chromosomes. There was a notable exception for the nucleolus-organizing region-bearing arm chromosome arm 6S, where dy increased chiasma frequency. Maize meiotic mutant desynaptic is a recombination modifier gene based on cytogenetic and segregation analyses.
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Affiliation(s)
- Y Ji
- Faculty of Genetics and Department of Soil and Crop Sciences, Texas A&M University, College Station, Texas 77843-2135, USA
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Affiliation(s)
- A W Burton
- Department of Anesthesiology, University of Texas Medical Branch, Galveston 77555-0591, USA.
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Burton AW, Conroy BP, Sims S, Solanki D, Williams CG. Complex regional pain syndrome type II as a complication of subclavian catheter insertion. Anesthesiology 1998; 89:804. [PMID: 9743433 DOI: 10.1097/00000542-199809000-00053] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Affiliation(s)
- T A Thurston
- Department of Anesthesiology, University of Texas Medical Branch at Galveston 77555-0591, USA
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Abstract
Recombination distances and linkage heterogeneity were compared among a wide range of maize inbreds, wide crosses and maize x teosinte hybrids. Twelve maize and four teosinte races were backcrossed to stocks fixed for rare marker alleles on chromosome arm 1L. Recombination fraction estimates were higher for exotic germplasm than for either U.S. maize or maize x teosinte crosses. Serrano, Tuxpeño and a US-adapted inbred line of tropical origin, NC300, exhibited enhanced recombination. Three of the four maize x teosinte hybrids had little or no recombination between two loci. The observed recombination "shrinkage" resulted from an apparent inversion in the vicinity of the Amp1 locus. Average recombination distances among common marker loci for composite maps were highly variable, even when map construction was restricted to maize germplasm of similar origins.
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Affiliation(s)
- C G Williams
- Department of Forest Science, Texas A&M University, College Station 77843, USA.
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Williams CG, Hamrick JL, Lewis PO. Multiple-population versus hierarchical conifer breeding programs: a comparison of genetic diversity levels. Theor Appl Genet 1995; 90:584-594. [PMID: 24173955 DOI: 10.1007/bf00222007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/1994] [Accepted: 09/30/1994] [Indexed: 06/02/2023]
Abstract
Advanced-generation domestication programs for forest-tree species has raised some concerns about the maintenance of genetic diversity in forest-tree breeding programs. Genetic diversity in natural stands was compared with two genetic conservation options for a third-generation elite Pinus taeda breeding population. The breeding population was subdivided either on the basis of geographic origin and selection goals (multiple-population or MPBS option) or stratified according to genetic value (hierarchical or HOPE option). Most allelic diversity in the natural stands of loblolly pine is present in the domesticated breeding populations. This was true at the aggregate level for both multiple-population (MPBS) and the hierarchical (HOPE) populations. Individual subpopulations within each option had less genetic diversity but it did not decline as generations of improvement increased. Genetic differentiation within the subdivided breeding populations ranged from 1 to 5%, genetic variability is within each subpopulation rather than among subpopulations for both MPBS (>95%) and the HOPE approaches (>98%). Nei's Gst estimates for amongpopulation differentiation were biased upwards relative to estimates of θ from Weir and Cockerham (1984).
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Affiliation(s)
- C G Williams
- Department of Genetics, North Carolina State University, Box 7614, 27695-7614, Raleigh North Carolina, USA
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Wyndham CH, Benade AJ, Williams CG, Strydom NB, Goldin A, Heyns AJ. Changes in central circulation and body fluid spaces during acclimatization to heat. J Appl Physiol (1985) 1968; 25:586-93. [PMID: 5687365 DOI: 10.1152/jappl.1968.25.5.586] [Citation(s) in RCA: 87] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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Williams CG, Wyndham CH, Heyns AJ. The component proportions of energy expended on an industrial task. Int Z Angew Physiol 1968; 25:39-45. [PMID: 5660926 DOI: 10.1007/bf00698833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Williams CG, Du Raan AJ, von Rahden MJ, Wyndham CH. The capacity for endurance work in highly trained men. Int Z Angew Physiol 1968; 26:141-9. [PMID: 5727800 DOI: 10.1007/bf00699511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Williams CG, Wyndham CH, Heyns A. The problem of "optimum" acclimatisation. Int Z Angew Physiol 1968; 26:298-308. [PMID: 5722019 DOI: 10.1007/bf00698306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Wyndham CH, Williams CG, Morrison JF, Heyns AJ, Siebert J. Tolerance of very hot humid environments by highly acclimatized Bantu at rest. Br J Ind Med 1968; 25:22-39. [PMID: 5642646 PMCID: PMC1008660 DOI: 10.1136/oem.25.1.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
In order to know as much as possible about human reactions under conditions of extreme ambient air temperatures, and about the ability of men to survive under these conditions and to assist in their own survival, a series of studies was made in which groups of 10 men were exposed to temperature conditions ranging from 96°F. to 104°F. wet bulb (W.B.). Rigid criteria were employed to decide when men should be withdrawn from the test conditions. These were: (a) reaching a rectal temperature of 104°F., (b) suffering from repeated attacks of heat collapse which prevented the subject from standing erect, and (c) suffering a change in temperament and being no longer susceptible to instructions. At W.B. temperatures of 104°F. and 102°F. the rectal temperatures of the men continued to rise in a straight line until they reached 104°F. There was no tendency for the rectal temperatures to reach a steady state. At 100°F. W.B. there was a definite tendency in the rectal temperatures towards a steady level, but a steady state was not reached until the rectal temperatures had reached 104°F. The same general trend was seen at 98°F., but the time taken to reach a steady state was increased considerably. At 96°F. the rectal temperatures reached a steady level of between 102°F. and 103°F. after about 12 hours of exposure. Superimposed on this steady level was a clearcut circadian rhythm in rectal temperature. At 104°F. the mean heart rate continued to rise until the men were withdrawn when it had reached 148 beats per minute. In all the other air conditions, the heart rates reached a relatively steady level and the maximum level attained was proportionate to the severity of the air conditions. The sweat rate increased steadily between 96°F. and 100°F. W.B. from 130 ml./hour to 300 ml./hour. Above 100°F. it increased sharply to reach 800 ml./hour at 102°F. and 875 ml./hour at 104°F. W.B. In contrast to the sweat rate, the hourly rate of water intake did not alter between 96°F. and 100°F. W.B., being approximately constant at 150 ml./hour, but at 102°F. and 104°F. W.B. it rose sharply to 310 ml./hour and 330 ml./hour respectively. The hourly urine output was 95 ml./hour at 96°F. W.B. but fell to 50 ml./hour at 98°F. W.B. and declined further to 35 ml./hour at 104°F. W.B. At 96°F. and 98°F. W.B. the water intake was approximately equal to the rate of sweat loss, but at 100°F. the sweat rate increased without any rise in water intake, so that the difference was about 150 ml./hour. At 102°F. and 104°F. W.B. the rate of sweating increased sharply. Although the rate of drinking also rose, the difference between intake and output had also increased to about 550 ml./hour at 104°F. W.B. The curve of the average rate of dehydration is very similar to that representing the rate of sweating. There was little difference in the rate of dehydration between 96°F. and 98°F. W.B., the rate being 80 ml./hour, but at 100°F. it rose to 210 ml./hour. Above 100°F. W.B. the rate of dehydration rose sharply as the rate of water intake lagged further behind the rate of sweating; it was 510 ml./hour at 104°F. W.B. The main psychological effects were on the men's temperaments. A number of men became aggressive, a few became hysterical, and a few maintained a stoical silence. At 96°F. W.B., when the men remained in the climatic rooms for 48 hours, there were periods of aggressive behaviour which alternated with apathy. Electroencephalograms were done on some subjects. No abnormalities of any kind were evoked or caused by exposure to heat. The tolerance times before which men, who were initially cool, would not have reached their limit of tolerance to heat were estimated.
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Williams CG, Wyndham CH, du Raan AJ, Kok R, Heyns A. A comparison of the physical work capacity of individuals as determined by various tasks. Int Z Angew Physiol 1967; 24:102-10. [PMID: 5582467 DOI: 10.1007/bf00698326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Wyndham CH, Williams CG, von Rahden MJ, Kok R, Strydom NB, Zwi S. The effect on the partial pressure of oxygen in arterial blood of exercise up to the individual's maximum at medium altitude. Life Sci 1967; 6:919-24. [PMID: 6038607 DOI: 10.1016/0024-3205(67)90077-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Wyndham CH, Williams CG, Morrison JF, Bredell GA. A comparison of multi-stress tests on the sweat rate-rectal temperature relationship. Int Z Angew Physiol 1967; 23:305-21. [PMID: 5588286 DOI: 10.1007/bf00698040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Wyndham CH, Williams CG, Watson MI, Munro AH. Improving the accuracy of prediction of an individual's maximum oxygen intake. Int Z Angew Physiol 1967; 23:354-66. [PMID: 5588291 DOI: 10.1007/bf00698045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Williams CG, Wyndham CH, Kok R, von Rahden MJ. Effect of training on maximum oxygen intake and on anaerobic metabolism in man. Int Z Angew Physiol 1967; 24:18-23. [PMID: 5592858 DOI: 10.1007/bf00693572] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Williams CG, Wyndham CH, Morrison JF. The influence of weight and of stature on the mechanical efficiency of men. Int Z Angew Physiol 1966; 23:107-24. [PMID: 5997633 DOI: 10.1007/bf00699300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Wyndham CH, Strydom NB, Williams CG, Morrison JF, Bredell GA. The heat reactions of Bantu males in various states of acclimatization. II. The limits of heat stress for a moderate rate of work. Int Z Angew Physiol 1966; 23:79-92. [PMID: 5997319 DOI: 10.1007/bf00716284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Wyndham CH, Strydom NB, Williams CG, Morrison JF, Bredell GA. The heat reactions of Bantu males in various states of acclimatization. I. The sweat rate-rectal temperature relationship. Int Z Angew Physiol 1966; 23:63-78. [PMID: 5995121 DOI: 10.1007/bf00716283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Wyndham CH, Morrison JF, Williams CG, Heyns A, Margo E, Brown AN, Astrup J. The relationship between energy expenditure and performance index in the task of shovelling sand. Ergonomics 1966; 9:371-378. [PMID: 5976535 DOI: 10.1080/00140136608964398] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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Wyndham CH, Strydom NB, Leary WP, Williams CG. Studies of the maximum capacity of men for physical effort. I. A comparison of methods of assessing the maximum oxygen intake. Int Z Angew Physiol 1966; 22:285-95. [PMID: 5989958 DOI: 10.1007/bf00698280] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Wyndham CH, Strydom NB, Leary WP, Williams CG, Morrison JF. Studies of the maximum capacity of men for physical effort. 3. The effects on the maximum oxygen intake of young males of a regime of regular exercise and an adequate diet. Int Z Angew Physiol 1966; 22:304-10. [PMID: 5989960 DOI: 10.1007/bf00698282] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Williams CG, Viljoen JH, van Graan CH, Munro A. The influence of lubrication on the energy cost of pushing a mine car. Int Z Angew Physiol 1966; 22:311-6. [PMID: 5989961 DOI: 10.1007/bf00698283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Strydom NB, Wyndham CH, Williams CG, Morrison JF, Bredell GA, Von Rahden MJ, Peter J. Energy requirements of acclimatized subjects in humid heat. Fed Proc 1966; 25:1366-71. [PMID: 5913913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Wyndham CH, Williams CG, Morrison JF, Watson M. The maximum oxygen intakes of men working on industrial tasks. Int Z Angew Physiol 1966; 22:141-8. [PMID: 5983819 DOI: 10.1007/bf00698149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Strydom NB, Wyndham CH, Williams CG, Morrison JF, Bredell GA, Benade AJ, Von Rahden M. Acclimatization to humid heat and the role of physical conditioning. J Appl Physiol (1985) 1966; 21:636-42. [PMID: 5934473 DOI: 10.1152/jappl.1966.21.2.636] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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