Quantum Diamonds at the Beach: Chemical Insights into Silica Growth on Nanoscale Diamond using Multimodal Characterization and Simulation

Surface chemistry of materials that host quantum bits such as diamond is an important avenue of exploration as quantum computation and quantum sensing platforms mature. Interfacing diamond in general and nanoscale diamond (ND) in particular with silica is a potential route to integrate room temperature quantum bits into photonic devices, fiber optics, cells, or tissues with flexible functionalization chemistry. While silica growth on ND cores has been used successfully for quantum sensing and biolabeling, the surface mechanism to initiate growth was unknown. This report describes the surface chemistry responsible for silica bond formation on diamond and uses X-ray absorption spectroscopy (XAS) to probe the diamond surface chemistry and its electronic structure with increasing silica thickness. A modified Stöber (Cigler) method was used to synthesize 2-35 nm thick shells of SiO2 onto carboxylic acid-rich ND cores. The diamond morphology, surface, and electronic structure were characterized by overlapping techniques including electron microscopy. Importantly, we discovered that SiO2 growth on carboxylated NDs eliminates the presence of carboxylic acids and that basic ethanolic solutions convert the ND surface to an alcohol-rich surface prior to silica growth. The data supports a mechanism that alcohols on the ND surface generate silyl-ether (ND-O-Si-(OH)3) bonds due to rehydroxylation by ammonium hydroxide in ethanol. The suppression of the diamond electronic structure as a function of SiO2 thickness was observed for the first time, and a maximum probing depth of ∼14 nm was calculated. XAS spectra based on the Auger electron escape depth was modeled using the NIST database for the Simulation of Electron Spectra for Surface Analysis (SESSA) to support our experimental results. Additionally, resonant inelastic X-ray scattering (RIXS) maps produced by the transition edge sensor reinforces the chemical analysis provided by XAS. Researchers using diamond or high-pressure high temperature (HPHT) NDs and other exotic materials (e.g., silicon carbide or cubic-boron nitride) for quantum sensing applications may exploit these results to design new layered or core-shell quantum sensors by forming covalent bonds via surface alcohol groups.

Multistate outbreak of turtle-associated salmonellosis highlights ongoing challenges with the illegal sale and distribution of small turtles

The sale and distribution of small turtles (shell length <4 inches) as pets has been banned in the United States since 1975 because of the risk of Salmonella transmission, especially to children. Despite this 48-year-old ban, salmonellosis outbreaks continue to be linked to contact with small turtles. During investigations of turtle-associated outbreaks, information regarding the turtle farm of origin is difficult to obtain because turtles are commonly sold by transient vendors. During 2020-2021, public health officials investigated a multistate illness outbreak caused by Salmonella enterica serotype Typhimurium linked to pet small turtles. Cases were defined as a laboratory-confirmed Salmonella Typhimurium infection highly related (within 0-6 allele differences) to the outbreak strain based on whole-genome sequencing analysis by core-genome multilocus sequence typing with illness onset occurring during 27 August 2020-14 May 2021. Forty-three patients were identified from 12 states; of these, 35% (15/43) were children <5 years old. Among patients with available information, 37% (14/38) were hospitalized, and one death was reported. Seventy-four percent (25/34) of patients reported turtle exposure in the week before illness onset, and 84% (16/19) specified exposure to small turtles. The outbreak strain was isolated from samples collected from a Pennsylvania patient's small turtle tank. Two patients reported purchasing their small turtles from pet stores. Salmonella Braenderup was isolated from samples collected from small turtles and their habitat at one of these stores; however, at that time, this strain was not associated with any human illnesses. This investigation was notable because of the documented sale of small turtles from several pet stores combined with the identification of a single small turtle supplier to these pet stores. The high proportion of children involved in this outbreak highlights the continued need to educate the pet industry as well as parents and caregivers about the risk of turtle-associated salmonellosis especially in children. Understanding and addressing the persisting challenges related to the illegal sale and distribution of small turtles could reduce the burden of turtle-associated salmonellosis.

Pyrethroid genetic resistance in the dengue vector (Aedes aegypti) in Posadas, Argentina

Pyrethroids are extensively used to control adult populations of the arboviral vector Aedes aegypti, raising concerns regarding the increasing frequency and distribution of insecticide resistance mutations (kdr: knock-down resistance) in the voltage-gated sodium channel gene (Nav). The widespread use of pyrethroids imposes a threat to the success of mosquito control and the environment. In this study, we investigated the presence of two kdr mutations (V1016I and F1534C) in the Nav gene and their distribution across four neighborhoods in Posadas, Argentina, with different Ae. aegypti abundance and contrasting socioeconomic status (SES). Alleles at each locus were interrogated using TaqMan SNP genotyping assays in DNA extracted from adult females collected in a longitudinal study. We report the presence of both pyrethroid resistance alleles (kdr 1016I = 29.08%; kdr 1534C = 70.70%) among adult females. The frequency of combined kdr genotypes reveals that approximately 70% of local adult females have enhanced resistance to pyrethroids. Both, the proportion of resistant adult females (with at least one kdr allele in each locus) and Ae. aegypti abundance showed an uneven distribution between neighborhoods with different SES (p < 0.001). In high-SES neighborhoods, we found more mosquitoes and a higher frequency of pyrethroid resistance, possibly as a consequence of different public health interventions, social habits, and insecticide use. This is the first report of kdr mutations in Ae. Aegypti in the northeast region of Argentina. Our results focus on the need for within-population (city) distribution analyses of kdr mutations and highlight the relevance of incorporating insecticide resistance monitoring within the Integrated Vector Management initiative.

Analysis of the Knockdown Resistance Locus (kdr) in Anopheles stephensi, An. arabiensis, and Culex pipiens s.l. for Insight Into the Evolution of Target-site Pyrethroid Resistance in Eastern Ethiopia

The malaria vector, Anopheles stephensi, which is typically restricted to South Asia and the Middle East, was recently detected in the Horn of Africa. Addressing the spread of this vector could involve integrated vector control that considers the status of insecticide resistance of multiple vector species in the region. Previous reports indicate that the knockdown resistance mutations (kdr) in the voltage-gated sodium channel (vgsc) are absent in both pyrethroid-resistant and pyrethroid-sensitive An. stephensi in eastern Ethiopia; however, similar information about other vector species in the same areas is limited. In this study, kdr and the neighboring intron were analyzed in An. stephensi, An. arabiensis, and Culex pipiens s.l. collected between 2016 and 2017 to determine the evolutionary history of kdr in eastern Ethiopia. A sequence analysis revealed that all of Cx. pipiens s.l. (N = 42) and 71.6% of the An. arabiensis (N = 67) carried kdr L1014F, which is known to confer target-site pyrethroid resistance. Intronic variation was only observed in An. stephensi (six segregating sites, three haplotypes), which was previously shown to have no kdr mutations. In addition, no evidence of non-neutral evolutionary processes was detected at the An. stephensi kdr intron, thereby further supporting the target-site mechanism not being a major resistance mechanism in this An. stephensi population. Overall, these results show key differences in the evolution of target-site pyrethroid/dichlorodiphenyltrichloroethane resistance mutations in populations of vector species from the same region. Variations in insecticide resistance mechanism profiles between eastern Ethiopian mosquito vectors may lead to different responses to insecticides used in integrated vector control.

Low Density Plasmodium Infections and G6PD Deficiency Among Malaria Suspected Febrile Individuals in Ethiopia

The identification and management of low parasitemia infections have become increasingly challenging for malaria control and elimination. Submicroscopic Plasmodium infections and G6PD deficiency among febrile patients require more sensitive diagnostic methods to improve detection and careful treatment regime of these infections. In Ethiopia, information on the low density submicroscopic malarial infections and frequency of G6PD deficiency (G6PDd) is scarce. In this study, 297 malaria suspected febrile patient samples were collected from health facilities of Bonga town in southwestern Ethiopia. The positivity rates of Plasmodium infection were determined by microscopy and quantitative PCR. G6PD activity level was determined by careSTART^™ G6PD biosensor and the frequency of three common variants: G6PD*A (A376G), G6PD*A- (G202A) and Mediterranean (C563T) were investigated. G6PD gene sequencing was performed to detect mutations in exons 2-11 for both G6PD normal and deficient samples based on the phenotypic assay. More than twice Plasmodium infected samples was detected by qPCR (52/297; 17.4%) than microscopy (21/297; 7.0%). About 31 (10%) of the infections were submicroscopic. Bednet usage and age had a significant association with Plasmodium infection. Of the 271 participants who were tested for G6PD phenotype, 19 (7.0%) had low G6PD level. No mutations were observed in A376G, G202A, and C563T in the G6PDd samples, but three novel non-synonymous mutations in exon 2 including a C to T transition at position ChrX:6504 (Arg to Thr), G to T at ChrX:6369 (Ser to IIe), and G to C at ChrX:6664 (Gln to His) were detected. A high number of submicroscopic Plasmodium infections observed in this study pose a challenge for accurate and timely diagnosis, which could hinder malaria control efforts. G6PD deficiency in malaria patients pose danger when treating patients with primaquine. The three novel mutations detected in exon 2 of the G6PD gene merit further investigation on the hemolytic risk when exposed to oxidative antimalarials, their prevalence, and clinical significance.

Genetic diversity of Anopheles stephensi in Ethiopia provides insight into patterns of spread

BACKGROUND

The recent detection of the South Asian malaria vector Anopheles stephensi in the Horn of Africa (HOA) raises concerns about the impact of this mosquito on malaria transmission in the region. Analysis of An. stephensi genetic diversity and population structure can provide insight into the history of the mosquito in the HOA to improve predictions of future spread. We investigated the genetic diversity of An. stephensi in eastern Ethiopia, where detection suggests a range expansion into this region, in order to understand the history of this invasive population.

METHODS

We sequenced the cytochrome oxidase subunit I (COI) and cytochrome B gene (CytB) in 187 An. stephensi collected from 10 sites in Ethiopia in 2018. Population genetic, phylogenetic, and minimum spanning network analyses were conducted for Ethiopian sequences. Molecular identification of blood meal sources was also performed using universal vertebrate CytB sequencing.

RESULTS

Six An. stephensi COI-CytB haplotypes were observed, with the highest number of haplotypes in the northeastern sites (Semera, Bati, and Gewana towns) relative to the southeastern sites (Kebridehar, Godey, and Degehabur) in eastern Ethiopia. We observed population differentiation, with the highest differentiation between the northeastern sites compared to central sites (Erer Gota, Dire Dawa, and Awash Sebat Kilo) and the southeastern sites. Phylogenetic and network analysis revealed that the HOA An. stephensi are more genetically similar to An. stephensi from southern Asia than from the Arabian Peninsula. Finally, molecular blood meal analysis revealed evidence of feeding on cows, goats, dogs, and humans, as well as evidence of multiple (mixed) blood meals.

CONCLUSION

We show that An. stephensi is genetically diverse in Ethiopia and with evidence of geographical structure. Variation in the level of diversity supports the hypothesis for a more recent introduction of An. stephensi into southeastern Ethiopia relative to the northeastern region. We also find evidence that supports the hypothesis that HOA An. stephensi populations originate from South Asia rather than the Arabian Peninsula. The evidence of both zoophagic and anthropophagic feeding support the need for additional investigation into the potential for livestock movement to play a role in vector spread in this region.

Plasmodium vivax From Duffy-Negative and Duffy-Positive Individuals Share Similar Gene Pools in East Africa

Plasmodium vivax malaria was thought to be rare in Africa, but an increasing number of P. vivax cases reported across Africa and in Duffy-negative individuals challenges this dogma. The genetic characteristics of P. vivax in Duffy-negative infections, the transmission of P. vivax in East Africa, and the impact of environments on transmission remain largely unknown. This study examined genetic and transmission features of P. vivax from 107 Duffy-negative and 305 Duffy-positive individuals in Ethiopia and Sudan. No clear genetic differentiation was found in P. vivax between the 2 Duffy groups, indicating between-host transmission. P. vivax from Ethiopia and Sudan showed similar genetic clusters, except samples from Khartoum, possibly due to distance and road density that inhibited parasite gene flow. This study is the first to show that P. vivax can transmit to and from Duffy-negative individuals and provides critical insights into the spread of P. vivax in sub-Saharan Africa.

Genetic variation of Plasmodium falciparum histidine-rich protein 2 and 3 in Assosa zone, Ethiopia: its impact on the performance of malaria rapid diagnostic tests

Background

Rapid diagnostic tests (RDT) are commonly used for the diagnosis of malaria caused by Plasmodium falciparum. However, false negative results of RDT caused by genetic variation of P. falciparum histidine-rich protein 2 and 3 genes (pfhrp2/3) threaten existing malaria case management and control efforts. The main objective of this study was to investigate the genetic variations of the pfhrp2/3 genes.

Methods

A cross-sectional study was conducted from malaria symptomatic individuals in 2018 in Assosa zone, Ethiopia. Finger-prick blood samples were collected for RDT and microscopic examination of thick and thin blood films. Dried blood spots (DBS) were used for genomic parasite DNA extraction and molecular detection. Amplification of parasite DNA was made by quantitative PCR. DNA amplicons of pfhrp2/3 were purified and sequenced.

Results

The PfHRP2 amino acid repeat type isolates were less conserved compared to the PfHRP3 repeat type. Eleven and eight previously characterized PfHRP2 and PfHRP3 amino acid repeat types were identified, respectively. Type 1, 4 and 7 repeats were shared by PfHRP2 and PfHRP3 proteins. Type 2 repeats were found only in PfHRP2, while types 16 and 17 were found only in PfHRP3 with a high frequency in all isolates. 18 novel repeat types were found in PfHRP2 and 13 novel repeat types were found in PfHRP3 in single or multiple copies per isolate. The positivity rate for PfHRP2 RDT was high, 82.9% in PfHRP2 and 84.3% in PfHRP3 sequence isolates at parasitaemia levels > 250 parasites/µl. Using the Baker model, 100% of the isolates in group A (If product of types 2 × type 7 repeats ≥ 100) and 73.7% of the isolates in group B (If product of types 2 × type 7 repeats 50–99) were predicted to be detected by PfHRP2 RDT at parasitaemia level > 250 parasite/μl.

Conclusion

The findings of this study indicate the presence of different PfHRP2 and PfHRP3 amino acid repeat including novel repeats in P. falciparum from Ethiopia. These results indicate that there is a need to closely monitor the performance of PfHRP2 RDT associated with the genetic variation of the pfhrp2 and pfhrp3 gene in P. falciparum isolates at the country-wide level.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-03928-3.

Modeling Plasmodium falciparum Diagnostic Test Sensitivity Using Machine Learning With Histidine-Rich Protein 2 Variants

Malaria, predominantly caused by Plasmodium falciparum, poses one of largest and most durable health threats in the world. Previously, simplistic regression-based models have been created to characterize malaria rapid diagnostic test performance, though these models often only include a couple genetic factors. Specifically, the Baker et al., 2005 model uses two types of particular repeats in histidine-rich protein 2 (PfHRP2) to describe a P. falciparum infection, though the efficacy of this model has waned over recent years due to genetic mutations in the parasite. In this work, we use a dataset of 100 P. falciparum PfHRP2 genetic sequences collected in Ethiopia and derived a larger set of motif repeat matches for use in generating a series of diagnostic machine learning models. Here we show that the usage of additional and different motif repeats in more sophisticated machine learning methods proves effective in characterizing PfHRP2 diversity. Furthermore, we use machine learning model explainability methods to highlight which of the repeat types are most important with regards to rapid diagnostic test sensitivity, thereby showcasing a novel methodology for identifying potential targets for future versions of rapid diagnostic tests.

Cryogenic spectrometer for measuring the far-IR to millimeter-wave absorptivity of cosmic analog dusts

We report on the design, construction, and performance of a custom apparatus built to measure the frequency- and temperature-dependent absorptivity of millimeter-wave light by cosmic analog dusts. We highlight the unique challenges faced as well as a few key innovations that are part of the instrument. Among those is an ultra-compact Fourier transform spectrometer. We have measured its effective frequency range and FWHM resolution to be 150-2100 GHz and ∼45GHz, respectively. Another innovation is a cold sample positioner whose temperature can be controlled within the range of 3.7-50 K. The use of a pulse-tube cryocooler results in a pulse-synchronous signal that dominates the detector (bolometer) signal. Methods used to address that challenge are also presented.

Cell-Free DNA Detection of Tumor Mutations in Heterogeneous, Localized Prostate Cancer Via Targeted, Multiregion Sequencing

Cell-free DNA (cfDNA) may allow for minimally invasive identification of biologically relevant genomic alterations and genetically distinct tumor subclones. Although existing biomarkers may detect localized prostate cancer, additional strategies interrogating genomic heterogeneity are necessary for identifying and monitoring aggressive disease. In this study, we aimed to evaluate whether circulating tumor DNA can detect genomic alterations present in multiple regions of localized prostate tumor tissue.

METHODS

Low-pass whole-genome and targeted sequencing with a machine-learning guided 2.5-Mb targeted panel were used to identify single nucleotide variants, small insertions and deletions (indels), and copy-number alterations in cfDNA. The majority of this study focuses on the subset of 21 patients with localized disease, although 45 total individuals were evaluated, including 15 healthy controls and nine men with metastatic castration-resistant prostate cancer. Plasma cfDNA was barcoded with duplex unique molecular identifiers. For localized cases, matched tumor tissue was collected from multiple regions (one to nine samples per patient) for comparison.

RESULTS

Somatic tumor variants present in heterogeneous tumor foci from patients with localized disease were detected in cfDNA, and cfDNA mutational burden was found to track with disease severity. Somatic tissue alterations were identified in cfDNA, including nonsynonymous variants in FOXA1, PTEN, MED12, and ATM. Detection of these overlapping variants was associated with seminal vesicle invasion (P = .019) and with the number of variants initially found in the matched tumor tissue samples (P = .0005).

CONCLUSION

Our findings demonstrate the potential of targeted cfDNA sequencing to detect somatic tissue alterations in heterogeneous, localized prostate cancer, especially in a setting where matched tumor tissue may be unavailable (ie, active surveillance or treatment monitoring).

Cell-free DNA concentration and fragment size as a biomarker for prostate cancer

Prostate cancer is the most commonly diagnosed neoplasm in American men. Although existing biomarkers may detect localized prostate cancer, additional strategies are necessary for improving detection and identifying aggressive disease that may require further intervention. One promising, minimally invasive biomarker is cell-free DNA (cfDNA), which consist of short DNA fragments released into circulation by dying or lysed cells that may reflect underlying cancer. Here we investigated whether differences in cfDNA concentration and cfDNA fragment size could improve the sensitivity for detecting more advanced and aggressive prostate cancer. This study included 268 individuals: 34 healthy controls, 112 men with localized prostate cancer who underwent radical prostatectomy (RP), and 122 men with metastatic castration-resistant prostate cancer (mCRPC). Plasma cfDNA concentration and fragment size were quantified with the Qubit 3.0 and the 2100 Bioanalyzer. The potential relationship between cfDNA concentration or fragment size and localized or mCRPC prostate cancer was evaluated with descriptive statistics, logistic regression, and area under the curve analysis with cross-validation. Plasma cfDNA concentrations were elevated in mCRPC patients in comparison to localized disease (OR_5ng/mL = 1.34, P = 0.027) or to being a control (OR_5ng/mL = 1.69, P = 0.034). Decreased average fragment size was associated with an increased risk of localized disease compared to controls (OR_5bp = 0.77, P = 0.0008). This study suggests that while cfDNA concentration can identify mCRPC patients, it is unable to distinguish between healthy individuals and patients with localized prostate cancer. In addition to PSA, average cfDNA fragment size may be an alternative that can differentiate between healthy individuals and those with localized disease, but the low sensitivity and specificity results in an imperfect diagnostic marker. While quantification of cfDNA may provide a quick, cost-effective approach to help guide treatment decisions in advanced disease, its use is limited in the setting of localized prostate cancer.

Detection of high prevalence of Plasmodium falciparum histidine-rich protein 2/3 gene deletions in Assosa zone, Ethiopia: implication for malaria diagnosis

Background

Rapid diagnostic tests (RDTs) targeting histidine rich protein 2(HRP2) are widely used for diagnosis of Plasmodium falciparum infections. Besides PfHRP2, the PfHRP3 antigen contributes to the detection of P. falciparum infections in PfHRP2 RDTs. However, the performance HRP2-based RDT is affected by pfhrp2/3 gene deletions resulting in false-negative test results. The objective of this study was to determine the presence and prevalence of pfhrp2/3 gene deletions including the respective flanking regions among symptomatic patients in Assosa zone, Northwest Ethiopia.

Methods

A health-facility based cross-sectional study was conducted in febrile patients seeking a malaria diagnosis in 2018. Blood samples were collected by finger-prick for microscopic examination of blood smears, malaria RDT, and molecular analysis using dried blood spots (DBS) prepared on Whatman filter paper. A total of 218 P. falciparum positive samples confirmed by quantitative PCR were included for molecular assay of pfhrp2/3 target gene.

Results

Of 218 P. falciparum positive samples, exon 2 deletions were observed in 17.9% of pfhrp2 gene and in 9.2% of pfhrp3 gene. A high proportion of deletions in short segments of pfhrp2 exon1-2 (50%) was also detected while the deletions of the pfhrp3 exon1-2 gene were 4.1%. The deletions were extended to the downstream and upstream of the flanking regions in pfhrp2/3 gene (above 30%). Of eighty-six PfHRP2 RDT negative samples, thirty-six lacked pfhrp2 exon 2. Five PfHRP2 RDT negative samples had double deletions in pfhrp2 exon 2 and pfhrp3 exon2. Of these double deletions, only two of the samples with a parasite density above 2000 parasite/µl were positive by the microscopy. Three samples with intact pfhrp3 exon2 in the pfhrp2 exon2 deleted parasite isolates were found to be positive by PfHRP2 RDT and microscopy with a parasite density above 10,000/µl.

Conclusion

This study confirms the presence of deletions of pfhrp2/3 gene including the flanking regions. Pfhrp2/3 gene deletions results in false-negative results undoubtedly affect the current malaria control and elimination effort in the country. However, further countrywide investigations are required to determine the magnitude of pfhrp2/3 gene deletions and its consequences on routine malaria diagnosis.

A machine learning approach to optimizing cell-free DNA sequencing panels: with an application to prostate cancer

BACKGROUND

Cell-free DNA's (cfDNA) use as a biomarker in cancer is challenging due to genetic heterogeneity of malignancies and rarity of tumor-derived molecules. Here we describe and demonstrate a novel machine-learning guided panel design strategy for improving the detection of tumor variants in cfDNA. Using this approach, we first generated a model to classify and score candidate variants for inclusion on a prostate cancer targeted sequencing panel. We then used this panel to screen tumor variants from prostate cancer patients with localized disease in both in silico and hybrid capture settings.

METHODS

Whole Genome Sequence (WGS) data from 550 prostate tumors was analyzed to build a targeted sequencing panel of single point and small (< 200 bp) indel mutations, which was subsequently screened in silico against prostate tumor sequences from 5 patients to assess performance against commonly used alternative panel designs. The panel's ability to detect tumor-derived cfDNA variants was then assessed using prospectively collected cfDNA and tumor foci from a test set 18 prostate cancer patients with localized disease undergoing radical proctectomy.

RESULTS

The panel generated from this approach identified as top candidates mutations in known driver genes (e.g. HRAS) and prostate cancer related transcription factor binding sites (e.g. MYC, AR). It outperformed two commonly used designs in detecting somatic mutations found in the cfDNA of 5 prostate cancer patients when analyzed in an in silico setting. Additionally, hybrid capture and 2500X sequencing of cfDNA molecules using the panel resulted in detection of tumor variants in all 18 patients of a test set, where 15 of the 18 patients had detected variants found in multiple foci.

CONCLUSION

Machine learning-prioritized targeted sequencing panels may prove useful for broad and sensitive variant detection in the cfDNA of heterogeneous diseases. This strategy has implications for disease detection and monitoring when applied to the cfDNA isolated from prostate cancer patients.

Evaluation of PfHRP2 and PfLDH Malaria Rapid Diagnostic Test Performance in Assosa Zone, Ethiopia

In malaria-endemic countries, rapid diagnostic tests (RDTs) targeting Plasmodium falciparum histidine-rich protein 2 (PfHRP2) and lactate dehydrogenase (PfLDH) have been widely used. However, little is known regarding the diagnostic performances of these RDTs in the Assosa zone of northwest Ethiopia. The objective of this study was to determine the diagnostic performances of PfHRP2 and PfLDH RDTs using microscopy and quantitative PCR (qPCR) as a reference test. A health facility-based cross-sectional study design was conducted from malaria-suspected study participants at selected health centers from November to December 2018. Finger-prick blood samples were collected for microscopy, RDTs, and qPCR method. The prevalence of P. falciparum was 26.4%, 30.3%, and 24.1% as determined by microscopy, PfHRP2 RDT, and PfLDH RDT, respectively. Compared with microscopy, the sensitivity and specificity of the PfHRP2 RDT were 96% and 93%, respectively, and those of the PfLDH RDT were 89% and 99%, respectively. Compared with qPCR, the specificity of the PfHRP2 RDT (93%) and PfLDH RDT (98%) was high, but the sensitivity of the PfHRP2 RDT (77%) and PfLDH RDT (70%) was relatively low. These malaria RDTs and reference microscopy methods showed reasonable agreement with a kappa value above 0.85 and provided accurate diagnosis of P. falciparum malaria. Thus, the current malaria RDT in the Ministry of Health program can be used in the Assosa zone of Ethiopia. However, continuous monitoring of the performance of PfHRP2 RDT is important to support control and elimination of malaria in Ethiopia.

Abstract 719: Assessing the utility of cell-free DNA in identifying prostate cancer and characterizing tumor heterogeneity via targeted, whole exome, and whole genome multi-region sequencing

Early cancer diagnosis, especially while the disease is localized and before symptoms appear, results in significantly higher survival rates compared to late-stage diagnosis. At the time of diagnosis, it is also common to find multiple foci within the prostate in men with localized disease. Cell-free DNA (cfDNA) are short DNA fragments released into circulation by dying cells, which may reflect underlying disease biology and simultaneously allow for the identification of genetically distinct tumor subclones. The objectives of this study are to determine if cfDNA concentration can be used to distinguish between healthy individuals from patients with localized or metastatic castration-resistant prostate cancer (mCRPC), and if somatic mutations identified in tumor tissue are detectable in cfDNA.

This study included samples from 277 individuals: 41 healthy donors, 112 patients with localized prostate cancer who underwent radical prostatectomy (RP) at UCSF, and 124 mCRPC patients. Whole peripheral blood was collected in EDTA tubes or PAXgene Blood ccfDNA tubes. Blood and matched tissue from adjacent normal seminal vesicles and multiple tumor regions (1-9 samples per patient) were collected from patients undergoing RP. Extraction of cfDNA was performed on double spun plasma using the Qiagen QIAamp Circulating Nucleic Acid Kits. After extraction, the concentration and fragment length distribution were measured with a Bioanalyzer 2100 Instrument. Fifty-seven samples (multiple tumor tissue foci and matched blood) from nine patients with localized disease were subjected to whole exome sequencing, and 22 samples from five patients were subjected to whole genome sequencing. All samples from 14 patients underwent targeted sequencing with a 2.5Mb panel generated via machine learning on TCGA prostate cancer sequence data. Somatic variant calling was performed with Broad Institute's Terra platform (GATK4/MuTect2) for tumor tissue and with the Curio platform for cfDNA to build consensus sequences leveraging duplex unique molecular tags. To estimate tumor fraction in cfDNA, ichorCNA was used to profile low pass whole genome sequence data.

Total cfDNA concentration was able to distinguish between healthy and metastatic (p = 0.001) participants, adjusted for age; and also between localized and metastatic groups (p &lt; 0.001), adjusted for age and PSA. Among the patients with localized disease, cfDNA concentration was not associated with age, PSA, Gleason score, or Decipher Score (a 22 gene metastasis risk-predicting RNA gene expression signature), suggesting the potential for this marker to be independent of factors that are commonly used to assess disease burden and risk of progression. Targeted sequencing of prostate tumors resulted in an average of 16 mutations with a range of 1 to 128 mutations per tissue region. The cfDNA allele frequencies for mutations identified in tumor tissue ranged from 0.5% to 20%. Four patients with variant detection in cfDNA also experienced biochemical recurrence. While copy number analysis identified clonal and potentially subclonal alterations in WGS tumor tissue, no alterations were found in WGS cfDNA. Further analysis of potential factors influencing variant detection in cfDNA (adverse pathology, starting amount of DNA, coverage) will be performed.

Citation Format: Emmalyn Chen, Clinton L. Cario, Lancelote Leong, Karen Lopez, César Márquez, Carissa Chu, Patricia S. Li, Erica Oropeza, Imelda Tenggara, Janet Cowan, Jeffry P. Simko, Daniel K. Wells, Robin Kageyama, June M. Chan, Terence Friedlander, Rahul Aggarwal, Felix Feng, Pamela L. Paris, Peter R. Carroll, John S. Witte. Assessing the utility of cell-free DNA in identifying prostate cancer and characterizing tumor heterogeneity via targeted, whole exome, and whole genome multi-region sequencing [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 719.

Insecticide resistance in Anopheles stephensi in Somali Region, eastern Ethiopia

Background

The movement of malaria vectors into new areas is a growing concern in the efforts to control malaria. The recent report of Anopheles stephensi in eastern Ethiopia has raised the necessity to understand the insecticide resistance status of the vector in the region to better inform vector-based interventions. The aim of this study was to evaluate insecticide resistance in An. stephensi in eastern Ethiopia using two approaches: (1) World Health Organization (WHO) bioassay tests in An. stephensi; and (2) genetic analysis of insecticide resistance genes in An. stephensi in eastern Ethiopia.

Methods

Mosquito larvae and pupae were collected from Kebri Dehar. Insecticide susceptibility of An. stephensi was tested with malathion 5%, bendiocarb 0.1%, propoxur 0.1%, deltamethrin 0.05%, permethrin 0.75%, pirimiphos-methyl 0.25% and DDT 4%, according to WHO standard protocols. In this study, the knockdown resistance locus (kdr) in the voltage gated sodium channel (vgsc) and ace1R locus in the acetylcholinesterase gene (ace-1) were analysed in An. stephensi.

Results

All An. stephensi samples were resistant to carbamates, with mortality rates of 23% and 21% for bendiocarb and propoxur, respectively. Adult An. stephensi was also resistant to pyrethroid insecticides with mortality rates 67% for deltamethrin and 53% for permethrin. Resistance to DDT and malathion was detected in An. stephensi with mortality rates of 32% as well as An. stephensi was resistance to pirimiphos-methyl with mortality rates 14%. Analysis of the insecticide resistance loci revealed the absence of kdr L1014F and L1014S mutations and the ace1R G119S mutation.

Conclusion

Overall, these findings support that An. stephensi is resistant to several classes of insecticides, most notably pyrethroids. However, the absence of the kdr L1014 gene may suggest non-target site resistance mechanisms. Continuous insecticide resistance monitoring should be carried out in the region to confirm the documented resistance and exploring mechanisms conferring resistance in An. stephensi in Ethiopia.

Owner and Veterinarian Perceptions About Use of a Canine Quality of Life Survey in Primary Care Settings

This paper describes dog owner and veterinarian perceptions around the use of a validated canine quality of life (QOL) survey to facilitate wellness conversations in two clinical settings: a veterinary teaching hospital (pilot, Phase 1) and five corporate general practice hospitals (Phase 2). Phase 1 results showed that dog owners felt the survey was valuable for understanding their dog's QOL, with 81% of owners expressing interest in learning more about canine QOL. Phase 2 reinforced owner perceptions about the survey conveyed during the pilot phase, and veterinarians reported that the survey facilitated client communication related to preventive care without increasing consultation time. These results demonstrate that beyond using QOL assessments to track patient health, the use of a QOL survey during veterinary visits could improve owner-veterinarian discussions around QOL, wellness, services and preventive care. To fully realize these benefits in clinical settings, veterinary staff preparation may be needed to communicate the purpose of QOL assessments to clients and thus facilitate deeper conversations about client needs and concerns. Key tools for achieving these could therefore include (1) sufficient veterinary team training to understand the QOL assessment and its purpose (2) training in how to communicate QOL to clients, and (3) reflexive use of QOL assessment results to engage clients in preventive care discussions. The veterinarian and client can then discuss the pros and cons of the various aspects of QOL and preventive care to arrive at a cooperative decision.

Kids N Fitness: A Group-based Pediatric Weight Management Curriculum Adapted for a Clinical Care Model

BACKGROUND

The current AAP clinical practice guidelines for the management of pediatric obesity recommend a structured, comprehensive, multi-disciplinary clinical intervention. However, there is a gap in the current literature on standardized curriculums for implementation of such programs. The objective of the present study is to adapt an evidenced-based, family- centered, weekly, weight management curriculum that addresses nutritional, physical activity and behavioral topics for a clinical care model at a tertiary care children's hospital.

METHODS

The curriculum was adapted for use in six individual sessions offered monthly by a multidisciplinary team, including a health educator, physician, dietitian, physical therapist and psychologist. Each provider offered specific feedback and curriculum adaptation based on their specialty. All team members completed training with scheduled treatment fidelity monitoring during implementation. To evaluate the effectiveness of the adapted curriculum, 60 adolescents, ages 14-18 years, with overweight or obesity, and at least one family member, will complete the six month intervention. The primary outcome is mean change in zBMI and %BMIp95 at six month and 18 months. Secondary outcomes include retention, satisfaction, effect on metabolic factors and activity level.

CONCLUSION

There is a paucity of literature on utilizing a standard curriculum in clinical weight management programs. Drawing from evidenced-based curriculum to strengthen clinical care creates an opportunity to improve existing clinical programs and potentially increase access and implementation of the current treatment recommendations for this high risk population.

Geographical distribution of Anopheles stephensi in eastern Ethiopia

Background

The recent detection of the South Asian malaria vector Anopheles stephensi in Ethiopia and other regions in the Horn of Africa has raised concerns about its potential impact on malaria transmission. We report here the findings of a survey for this species in eastern Ethiopia using both morphological and molecular methods for species identification.

Methods

Adult and larval/pupal collections were conducted at ten sites in eastern Ethiopia and Anopheles specimens were identified using standard morphological keys and genetic analysis.

Results

In total, 2231 morphologically identified An. stephensi were collected. A molecular approach incorporating both PCR endpoint assay and sequencing of portions of the internal transcribed spacer 2 (ITS2) and cytochrome c oxidase subunit 1 (cox1) loci confirmed the identity of the An. stephensi in most cases (119/124 of the morphologically identified An. stephensi confirmed molecularly). Additionally, we observed Aedes aegypti larvae and pupae at many of the An. stephensi larval habitats.

Conclusions

Our findings show that An. stephensi is widely distributed in eastern Ethiopia and highlight the need for further surveillance in the southern, western and northern parts of the country and throughout the Horn of Africa.

Towards an exposure narrative for metals and arsenic in historically contaminated Ni refinery soils: Relationships between speciation, bioavailability, and bioaccessibility

Archived soils contaminated with Ni, Cu, Co, and As from legacy operations of a nickel refinery at Port Colborne, Ontario, Canada were speciated using mineral liberation analysis. Four Ni minerals were identified as fingerprint compounds of the historical refinery emissions. Cu and Co were present in solid solution in these minerals due to their presence in the refinery's feed. The highest concentrations of Ni, Cu, Co, and As in these soils were 18,553, 1915, 196, and 79mg/kg, respectively, these elevated contaminant concentrations attesting to the importance of incidental soil ingestion to the oral exposure pathway in Port Colborne. The in vitro gastric bioaccessibility (BAc) was determined for these contaminants, as was in vivo oral bioavailability (BAv), using a mass balance approach in male Sprague-Dawley rats. In spite of the elevated soil concentrations of Cu, the BAv of this physiologically important metal could not be distinguished from that in commercial rat chow, suggesting low potential for exposure. Co and As also had low apparent BAv (<2%). For Ni, baseline oral BAv of naturally sourced dietary Ni was found to be approximately 2%, as was the oral BAv of Ni from nickel sulfate hexahydrate. The mass balances of NiSO₄·6H₂O were fully accounted-for in urine and feces after a single gavage dose, indicating little to no organ incorporation from this highly soluble salt. Therefore, the urinary estimates of Ni BAv for these soils were assumed to represent true BAv despite variable fecal recoveries. The high Ni concentrations enabled BAc-BAv relationships to be developed for these contaminated soils. For absolute bioavailability (ABA) and relative bioavailability (RBA) the relationships were: ABA=0.0116(BAc)-0.0479 and RBA=0.5542(BAc)-2.2817. These findings will advance the development of robust exposure narratives for soil metal contamination in Port Colborne and elsewhere.

Understanding Health Management for Adults With Autism

Date Presented 04/06/19

Adults with autism experience significant health disparities, including higher rates of chronic disease, less access to health services, and younger mortality rates. In this research project, we used qualitative methods to interview adults with autism, their caregivers, and their healthcare providers to develop an understanding of why these health disparities occur and to guide future intervention work.

Primary Author and Speaker: Jaclyn Schwartz

Contributing Authors: Jeanette Alam, Elena Cotayo, Sofia Espinosa, Dominique Grossman, Patricia Herdocia, Veronica Hernandez, Berline Lherisson, Karen Lopez, Jennifer Mejia, Cati Rodriguez, Melissa Rodriguez, Jessica Torres

Abstract 1371: Assessing the utility of cell-free DNA in identifying prostate cancer and characterizing tumor heterogeneity via whole exome and whole genome, multi-region sequencing

Early cancer diagnosis, especially while the disease is still localized and before symptoms appear, results in significantly higher survival rates compared to late-stage diagnosis. At the time of diagnosis, it is also common to find multiple foci within a single prostate gland in men with localized disease. Cell-free DNA (cfDNA) may not only reflect underlying disease biology, but also simultaneously allow for the identification of genetically distinct tumor subclones. The objectives of this study are to determine if 1) cfDNA levels are able to distinguish between healthy individuals from patients with localized or metastatic castration-resistant prostate cancer (mCRPC), and 2) if somatic mutations identified in tumor tissue are detectable in cfDNA and representative of the distribution observed in tumor tissue.

This study includes samples from 130 individuals at UCSF: 21 healthy donors, 100 patients with localized prostate cancer who underwent radical prostatectomy (RP), and 9 mCRPC patients. Blood samples and matched tissue from adjacent normal seminal vesicles and multiple tumor regions (1-9 samples per patient) were collected from patients undergoing radical prostatectomy. CfDNA was extracted from plasma, and the concentration and fragment length distribution were measured with a Bioanalyzer 2100. Comparisons of cfDNA levels between groups were assessed with a Welch’s t-test due to the potential for unequal variances. Fifty-seven samples from nine patients have been subjected to whole exome sequencing, and 22 samples from five patients have been subjected to whole genome sequencing at ~40x coverage. Somatic variant calling was performed with Broad Institute’s Firecloud platform (GATK4/MuTect2) for tumor tissue and with the Curio platform for cfDNA to build consensus sequences leveraging unique molecular tags.

CfDNA levels are able to distinguish between healthy and localized (p = 0.005), as well as healthy and metastatic groups (p = 0.043). Tumor foci within a patient’s prostate gland are genetically heterogeneous, with the majority of somatic mutations private to tumor regions and a subset of mutations at the intersection of these regions. Preliminary analyses result in an average of 72 somatic SNVs and indels per tumor tissue region, with ~10% overlap between regions in the same patient. Additional mCRPC and follow-up blood samples are being collected from all patients. The association between cfDNA levels prior to RP surgery and biochemical recurrence will be investigated when follow-up collection concludes. Further analysis of mutational concordance, clonality, and copy number variation between tumor tissue DNA and cfDNA, along with clinical data, will be performed.

Citation Format: Emmalyn Chen, Clinton Cario, Lancelote Leong, Karen Lopez, Patricia Li, Erica Oropeza, Imelda Tenggara, Janet Cowan, Jeffry Simko, Daniel Wells, Robin Kageyama, June Chan, Terence Friedlander, Pamela Paris, Peter Carroll, John Witte. Assessing the utility of cell-free DNA in identifying prostate cancer and characterizing tumor heterogeneity via whole exome and whole genome, multi-region sequencing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1371.

Discovery of Adults Linked to Cloning Oceanic Starfish Larvae (Oreaster, Asteroidea: Echinodermata)

Two juvenile specimens of a new species of Oreaster were collected at Parque Nacional Arrecife Alacranes and Triángulos Oeste in the southern Gulf of Mexico. DNA of mitochondrial loci identifies them as members of the same clade as cloning larvae of Oreaster found abundantly in waters of the Florida Current-Gulf Stream system, and distinct from Oreaster clavatus and Oreaster reticulatus, the two known Oreasteridae species in the North Atlantic. Larvae from the new species of Oreaster persist as clones but also metamorphose and settle to the benthos with typical asteroid morphology.

Sustained rescue of prefrontal circuit dysfunction by antidepressant-induced spine formation

The neurobiological mechanisms underlying the induction and remission of depressive episodes over time are not well understood. Through repeated longitudinal imaging of medial prefrontal microcircuits in the living brain, we found that prefrontal spinogenesis plays a critical role in sustaining specific antidepressant behavioral effects and maintaining long-term behavioral remission. Depression-related behavior was associated with targeted, branch-specific elimination of postsynaptic dendritic spines on prefrontal projection neurons. Antidepressant-dose ketamine reversed these effects by selectively rescuing eliminated spines and restoring coordinated activity in multicellular ensembles that predict motivated escape behavior. Prefrontal spinogenesis was required for the long-term maintenance of antidepressant effects on motivated escape behavior but not for their initial induction.

Sequence-based identification of Anopheles species in eastern Ethiopia

BACKGROUND

The recent finding of a typically non-African Anopheles species in eastern Ethiopia emphasizes the need for detailed species identification and characterization for effective malaria vector surveillance. Molecular approaches increase the accuracy and interoperability of vector surveillance data. To develop effective molecular assays for Anopheles identification, it is important to evaluate different genetic loci for the ability to characterize species and population level variation. Here the utility of the internal transcribed spacer 2 (ITS2) and cytochrome oxidase I (COI) loci for detection of Anopheles species from understudied regions of eastern Ethiopia was investigated.

METHODS

Adult mosquitoes were collected from the Harewe locality (east) and Meki (east central) Ethiopia. PCR and Sanger sequencing were performed for portions of the ITS2 and COI loci. Both NCBI's Basic Local Alignment Search tool (BLAST) and phylogenetic analysis using a maximum-likelihood approach were performed to identify species of Anopheles specimens.

RESULTS

Two species from the east Ethiopian collection, Anopheles arabiensis and Anopheles pretoriensis were identified. Analyses of ITS2 locus resulted in delineation of both species. In contrast, analysis of COI locus could not be used to delineate An. arabiensis from other taxa in Anopheles gambiae complex, but could distinguish An. pretoriensis sequences from sister taxa.

CONCLUSION

The lack of clarity from COI sequence analysis highlights potential challenges of species identification within species complexes. These results provide supporting data for the development of molecular assays for delineation of Anopheles in east Ethiopia.

Abstract 3669: Assessing the genetic heterogeneity of localized, multifocal prostate cancer via cell-free DNA

At the time of diagnosis, it is common to find multiple spatially distinct foci within a single prostate gland in men with prostate cancer. Recent studies evaluating the genetic heterogeneity of localized, multifocal prostate cancers through whole-genome sequencing and whole-exome sequencing have only recently been described. These tumors were highly heterogeneous for single-nucleotide variants, copy number alterations, and genomic rearrangements. One exciting use of cfDNA is its potential ability to simultaneously capture all genetically distinct tumor subclones. Currently, the degree to which a cfDNA sample is representative of the entire genetic landscape of localized prostate cancer is unknown. The objective of this study is to determine if somatic mutations identified in tumor tissue are detectable in cfDNA. Tumor tissue and blood samples have been collected from twenty-nine patients undergoing radical prostatectomy. Samples from fourteen patients have already been subjected to whole-exome sequencing with a target sequencing depth of 200X (HiSeq 4000). Preliminary analyses indicate that tumor foci within a single prostate gland in an individual are genetically heterogeneous. Further analysis of mutational concordance between tumor tissue DNA and cfDNA along with clinical data will be performed.

Citation Format: Emmalyn Chen, Clinton L. Cario, Lancelote Leong, Karen Lopez, Jeffry P. Simko, Peter R. Carroll, Caroline Tai, John S. Witte. Assessing the genetic heterogeneity of localized, multifocal prostate cancer via cell-free DNA [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3669.

Glucose-6-Phosphate Dehydrogenase Deficiency Genetic Variants in Malaria Patients in Southwestern Ethiopia

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked erythrocyte enzyme disorder with relevance to malaria treatment policy. Treatment with the antimalarial primaquine can result in hemolytic anemia in G6PD-deficient patients. With increased interest in primaquine use, it is important to identify G6PD variants in Ethiopia to inform malaria treatment policy. In the present study, mutations in the G6PD gene are identified in a sample of patients with malaria in Jimma town in southwest Ethiopia. Plasmodium species of infection were confirmed using polymerase chain reaction (PCR) and gel electrophoresis. PCR and Sanger sequencing were performed to observe a portion of the G6PD gene where the common G6PD mutations (A376G, G202A, and C563T) are found. Molecular analysis revealed that most of the samples were single Plasmodium vivax infections (83.7%). For G6PD genotyping, A376G was detected in 23.26% of individuals, whereas G202A and C563T were absent. Three other uncommon mutations were identified: rs782669677 (535G→A), rs370658483, (485 + 37 G→T), and a new mutation at chrX:154535443(C→T). Bioinformatic analysis of these mutations' potential functional impact suggests minimal effect on protein function. The discovery of both common and uncommon G6PD mutations contributes to the discussion on G6PD deficiency and appropriate primaquine treatment in Ethiopia.

Summarizing US Wildlife Trade with an Eye Toward Assessing the Risk of Infectious Disease Introduction

The aim of this study was to characterize the role of the USA in the global exchange of wildlife and describe high volume trade with an eye toward prioritizing health risk assessment questions for further analysis. Here we summarize nearly 14 years (2000-2013) of the most comprehensive data available (USFWS LEMIS system), involving 11 billion individual specimens and an additional 977 million kilograms of wildlife. The majority of shipments contained mammals (27%), while the majority of specimens imported were shells (57%) and tropical fish (25%). Most imports were facilitated by the aquatic and pet industry, resulting in one-third of all shipments containing live animals. The importer reported origin of wildlife was 77.7% wild-caught and 17.7% captive-reared. Indonesia was the leading exporter of legal shipments, while Mexico was the leading source reported for illegal shipments. At the specimen level, China was the leading exporter of legal and illegal wildlife imports. The number of annual declared shipments doubled during the period examined, illustrating continually increasing demand, which reinforces the need to scale up capacity for border inspections, risk management protocols and disease surveillance. Most regulatory oversight of wildlife trade is aimed at conservation, rather than prevention of disease introduction.

Influenza-like illness surveillance on the California-Mexico border, 2004-2009

BACKGROUND

Since 2004, the Naval Health Research Center, with San Diego and Imperial counties, has collaborated with the US Centers for Disease Control and Prevention to conduct respiratory disease surveillance in the US-Mexico border region. In 2007, the Secretariat of Health, Mexico and the Institute of Public Health of Baja California joined the collaboration.

OBJECTIVES

The identification of circulating respiratory pathogens in respiratory specimens from patients with influenza-like illness (ILI).

METHODS

Demographic, symptom information and respiratory swabs were collected from enrollees who met the case definition for ILI. Specimens underwent PCR testing and culture in virology and bacteriology.

RESULTS

From 2004 through 2009, 1855 persons were sampled. Overall, 36% of the participants had a pathogen identified. The most frequent pathogen was influenza (25%), with those aged 6-15 years the most frequently affected. In April 2009, a young female participant from Imperial County, California, was among the first documented cases of 2009 H1N1. Additional pathogens included influenza B, adenovirus, parainfluenza virus, respiratory syncytial virus, enterovirus, herpes simplex virus, Streptococcus pneumoniae, and Streptococcus pyogenes.

CONCLUSIONS

The US-Mexico border is one of the busiest in the world, with a large number of daily crossings. Due to its traffic, this area is an ideal location for surveillance sites. We identified a pathogen in 36% of the specimens tested, with influenza A the most common pathogen. A number of other viral and bacterial respiratory pathogens were identified. An understanding of the incidence of respiratory pathogens in border populations is useful for development of regional vaccination and disease prevention responses.

Platelet dysfunction in myelodysplastic syndromes: a clinicopathological study

Forty-eight patients with myelodysplastic syndromes and a platelet count greater than 80 x 10(9)/L were the subjects of a study of platelet function. A whole-blood platelet lumi-aggregometer was used for simultaneous measurement of platelet aggregation by the impedance method and of adenosine triphosphate-dense granule release. The results were correlated with skin bleeding time and episodes of clinical bleeding or thrombosis. Thirty-five patients had at least 1 abnormal result indicating platelet hypoactivity; 7 patients had mixed platelet hypoactivity and hyperactivity; and 4 patients had platelet hyperactivity. Only 2 patients had normal results. There was good correlation between platelet hypoactivity and prolonged skin bleeding time (P = .005); however, several patients with platelet hypoactivity had normal skin bleeding times. This finding suggested that whole-blood platelet aggregation studies may be more sensitive than bleeding time in identification of patients at risk of bleeding. Clinical hemorrhage was frequent (32 patients) in this cohort despite platelet counts greater than 100 x 10(9)/L. This finding indicated platelet hypofunction was clinically important. In contrast, only 2 of the 13 patients with thrombotic events had evidence of platelet hyperactivity, suggesting that other clinical factors are probably more important determinants of thrombosis. These observations confirm that platelet dysfunction is common in patients with myelodysplastic syndromes and suggest a useful role for routine whole-blood platelet aggregation studies to identify patients at risk of bleeding.

Cranial neural crest cells contribute to connective tissue in cranial muscles in the anuran amphibian, Bombina orientalis

The contribution of cranial neural crest cells to the development and patterning of cranial muscles in amphibians was investigated in the phylogenetically basal and morphologically generalized frog, Bombina orientalis. Experimental methods included fluorescent marking of premigratory cranial neural crest and extirpation of individual migratory streams. Neural crest cells contributed to the connective tissue component, but not the myofibers, of many larval muscles within the first two branchial arches (mandibular and hyoid), and complex changes in muscle patterning followed neural crest extirpation. Connective tissue components of individual muscles of either arch originate from the particular crest migratory stream that is associated with that arch, and this relationship is maintained regardless of the segmental identity-or embryonic derivation-of associated skeletal components. These developmental relations define a pattern of segmentation in the head of larval anurans that is similar to that previously described in the domestic chicken, the only vertebrate that has been thoroughly investigated in this respect. The fundamental role of the neural crest in patterning skeleton and musculature may represent a primitive feature of cranial development in vertebrates. Moreover, the corresponding developmental processes and cell fates appear to be conserved even when major evolutionary innovations-such as the novel cartilages and muscles of anuran larvae-result in major differences in cranial form.

Thrombosis and bleeding in myeloproliferative disorders: identification of at-risk patients with whole blood platelet aggregation studies

Seventy-five patients with chronic myeloproliferative disorders were studied to investigate platelet function by simultaneous measurement of platelet aggregation by the impedance method and ATP dense granule release using a whole blood platelet lumi-aggregometer, in an attempt to identify patients at risk for thrombosis and bleeding. Thirty-nine patients had at least one abnormal result indicating platelet hyperactivity (i.e. impedance or release with one agonist being above the reference range); 16 patients had platelet hypoactivity (i.e. at least one result was below the reference range), whilst 14 had co-existence of hyper- and hypoactivity. Six patients had normal results. 20/53 patients with platelet hyperactivity (alone or mixed) had a positive history of venous and/or arterial thrombosis; in comparison, only two of the other 22 patients had a positive history. During a median follow-up of 33 months, nine patients with and one patient without platelet hyperactivity respectively developed new thrombotic events before the addition of specific therapy. A total of 50 patients with and eight patients without platelet hyperactivity respectively received specific treatment including aspirin and/or cytotoxic therapy. All but one elderly patient with platelet hyperactivity have remained free of new thrombotic events on specific therapy. Two of the 17 patients with platelet hypoactivity had major clinical bleeding. These observations highlight the need to test platelets for hyper- as well as hypo-function and suggest a useful role for routine whole blood platelet aggregation studies to identify the patients at risk for thrombosis or bleeding.

Bispecific monoclonal antibody complexes bound to primate erythrocyte complement receptor 1 facilitate virus clearance in a monkey model

We investigated the feasibility of using bispecific mAb complexes to redirect and improve the efficiency of the primate E complement receptor 1-based clearance reaction to remove a virus from the circulation. As an initial approach, we used bacteriophage phiX174 as an immunologic model for mammalian viruses. Bispecific complexes were prepared by chemically cross-linking a mAb specific for complement receptor 1 with a mAb specific for the bacteriophage phiX174. In a monkey model these complexes facilitate rapid and quantitative binding of the target bacteriophage to E in vitro and in vivo. Moreover, after in vivo binding to E, the complexes containing mAb and prototype virus are rapidly cleared from the circulation of rhesus and cynomolgus monkeys without loss of E. Our findings suggest that bispecific mAb complexes, in concert with primate E complement receptor 1, may have therapeutic utility in the treatment of diseases associated with blood-borne pathogens.

Bispecific monoclonal antibody complexes bound to primate erythrocyte complement receptor 1 facilitate virus clearance in a monkey model

We investigated the feasibility of using bispecific mAb complexes to redirect and improve the efficiency of the primate E complement receptor 1-based clearance reaction to remove a virus from the circulation. As an initial approach, we used bacteriophage phiX174 as an immunologic model for mammalian viruses. Bispecific complexes were prepared by chemically cross-linking a mAb specific for complement receptor 1 with a mAb specific for the bacteriophage phiX174. In a monkey model these complexes facilitate rapid and quantitative binding of the target bacteriophage to E in vitro and in vivo. Moreover, after in vivo binding to E, the complexes containing mAb and prototype virus are rapidly cleared from the circulation of rhesus and cynomolgus monkeys without loss of E. Our findings suggest that bispecific mAb complexes, in concert with primate E complement receptor 1, may have therapeutic utility in the treatment of diseases associated with blood-borne pathogens.

Effectiveness of a consultation intervention to promote tobacco control policies in Northwest Indian tribes: integrating experimental evaluation and service delivery

A quasi-experimental replication of an intervention for promoting tobacco control policies in Northwest Indian tribes is described and the process of intervention including issues of collaboration among research institutions and Indian organizations is discussed. The policy intervention was evaluated using a pretest-posttest design wherein 20 tribes that had served as wait-list controls now received the intervention. The intervention comprised a tribal representative attending a kickoff orientation; follow-up visits to the tribes; distribution of tobacco policy workbooks; and phone call consultations. Policy status and stringency were assessed by means of telephone interviews with two key contacts per tribe, and by a count of enacted policies. There were significant pre-post changes in the primary outcome measure, a composite summary score of tobacco policy stringency, and changes were also reflected in enacted policies. The intervention effects observed were similar to those found in the prior randomized trial and suggest a robust, disseminable intervention. Much of the success achieved was attributed to the role of an Indian organization in planning the project and implementing the intervention and evaluation protocols.