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1.
BMC Med Inform Decis Mak ; 23(1): 238, 2023 10 25.
Artículo en Inglés | MEDLINE | ID: mdl-37880712

RESUMEN

BACKGROUND: Online questionnaires are commonly used to collect information from participants in epidemiological studies. This requires building questionnaires using machine-readable formats that can be delivered to study participants using web-based technologies such as progressive web applications. However, the paucity of open-source markup standards with support for complex logic make collaborative development of web-based questionnaire modules difficult. This often prevents interoperability and reusability of questionnaire modules across epidemiological studies. RESULTS: We developed an open-source markup language for presentation of questionnaire content and logic, Quest, within a real-time renderer that enables the user to test logic (e.g., skip patterns) and view the structure of data collection. We provide the Quest markup language, an in-browser markup rendering tool, questionnaire development tool and an example web application that embeds the renderer, developed for The Connect for Cancer Prevention Study. CONCLUSION: A markup language can specify both the content and logic of a questionnaire as plain text. Questionnaire markup, such as Quest, can become a standard format for storing questionnaires or sharing questionnaires across the web. Quest is a step towards generation of FAIR data in epidemiological studies by facilitating reusability of questionnaires and data interoperability using open-source tools.


Asunto(s)
Programas Informáticos , Humanos , Encuestas y Cuestionarios , Estudios Epidemiológicos
2.
Cancer Causes Control ; 27(12): 1429-1435, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27804056

RESUMEN

PURPOSE: Tobacco smoking and occupational exposures are the leading risk factors for developing urothelial bladder carcinoma (UBC), yet little is known about the contribution of these two factors to risk of UBC recurrence. We evaluated whether smoking status and usual adult occupation are associated with time to UBC recurrence for 406 patients with muscle-invasive bladder cancer submitted to The Cancer Genome Atlas (TCGA) project. METHODS: Kaplan-Meier and Cox proportional hazard methods were used to assess the association between smoking status, employment in a high-risk occupation for bladder cancer, occupational diesel exhaust exposure, and 2010 Standard Occupational Classification group and time to UBC recurrence. RESULTS: Data on time to recurrence were available for 358 patients over a median follow-up time of 15 months. Of these, 133 (37.2%) experienced a recurrence. Current smokers who smoked for more than 40 pack-years had an increased risk of recurrence compared to never smokers (HR 2.1, 95% CI 1.1, 4.1). Additionally, employment in a high-risk occupation was associated with a shorter time to recurrence (log-rank p = 0.005). We found an increased risk of recurrence for those employed in occupations with probable diesel exhaust exposure (HR 1.8, 95% CI 1.1, 3.0) and for those employed in production occupations (HR 2.0, 95% CI 1.1, 3.6). CONCLUSIONS: These findings suggest smoking status impacts risk of UBC recurrence, although several previous studies provided equivocal evidence regarding this association. In addition to the known causal relationship between occupational exposure and bladder cancer risk, our study suggests that occupation may also be related to increased risk of recurrence.


Asunto(s)
Recurrencia Local de Neoplasia/epidemiología , Exposición Profesional/estadística & datos numéricos , Ocupaciones/estadística & datos numéricos , Fumar/epidemiología , Neoplasias de la Vejiga Urinaria/epidemiología , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia/genética , Recurrencia Local de Neoplasia/patología , Factores de Riesgo , Fumar/efectos adversos , Fumar/genética , Fumar/patología , Estados Unidos/epidemiología , Neoplasias de la Vejiga Urinaria/genética , Neoplasias de la Vejiga Urinaria/patología
3.
Occup Environ Med ; 73(6): 417-24, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27102331

RESUMEN

BACKGROUND: Mapping job titles to standardised occupation classification (SOC) codes is an important step in identifying occupational risk factors in epidemiological studies. Because manual coding is time-consuming and has moderate reliability, we developed an algorithm called SOCcer (Standardized Occupation Coding for Computer-assisted Epidemiologic Research) to assign SOC-2010 codes based on free-text job description components. METHODS: Job title and task-based classifiers were developed by comparing job descriptions to multiple sources linking job and task descriptions to SOC codes. An industry-based classifier was developed based on the SOC prevalence within an industry. These classifiers were used in a logistic model trained using 14 983 jobs with expert-assigned SOC codes to obtain empirical weights for an algorithm that scored each SOC/job description. We assigned the highest scoring SOC code to each job. SOCcer was validated in 2 occupational data sources by comparing SOC codes obtained from SOCcer to expert assigned SOC codes and lead exposure estimates obtained by linking SOC codes to a job-exposure matrix. RESULTS: For 11 991 case-control study jobs, SOCcer-assigned codes agreed with 44.5% and 76.3% of manually assigned codes at the 6-digit and 2-digit level, respectively. Agreement increased with the score, providing a mechanism to identify assignments needing review. Good agreement was observed between lead estimates based on SOCcer and manual SOC assignments (κ 0.6-0.8). Poorer performance was observed for inspection job descriptions, which included abbreviations and worksite-specific terminology. CONCLUSIONS: Although some manual coding will remain necessary, using SOCcer may improve the efficiency of incorporating occupation into large-scale epidemiological studies.


Asunto(s)
Industrias/clasificación , Perfil Laboral , Procesamiento de Lenguaje Natural , Ocupaciones/clasificación , Algoritmos , Carcinoma de Células Renales , Estudios de Casos y Controles , Métodos Epidemiológicos , Estudios Epidemiológicos , Humanos , Modelos Logísticos , Reproducibilidad de los Resultados , Programas Informáticos , Estados Unidos , United States Occupational Safety and Health Administration
4.
BMC Bioinformatics ; 16: 170, 2015 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-26001675

RESUMEN

BACKGROUND: Partitioning the human immunoglobulin variable region into variable (V), diversity (D), and joining (J) segments is a common sequence analysis step. We introduce a novel approximate dynamic programming method that uses conserved immunoglobulin gene motifs to improve performance of aligning V-segments of rearranged immunoglobulin (Ig) genes. Our new algorithm enhances the former JOINSOLVER algorithm by processing sequences with insertions and/or deletions (indels) and improves the efficiency for large datasets provided by high throughput sequencing. RESULTS: In our simulations, which include rearrangements with indels, the V-matching success rate improved from 61% for partial alignments of sequences with indels in the original algorithm to over 99% in the approximate algorithm. An improvement in the alignment of human VDJ rearrangements over the initial JOINSOLVER algorithm was also seen when compared to the Stanford.S22 human Ig dataset with an online VDJ partitioning software evaluation tool. CONCLUSIONS: HTJoinSolver can rapidly identify V- and J-segments with indels to high accuracy for mutated sequences when the mutation probability is around 30% and 20% respectively. The D-segment is much harder to fit even at 20% mutation probability. For all segments, the probability of correctly matching V, D, and J increases with our alignment score.


Asunto(s)
Algoritmos , Biología Computacional/métodos , Reordenamiento Génico , Región de Unión de la Inmunoglobulina/genética , Región Variable de Inmunoglobulina/genética , Mutación/genética , Programas Informáticos , Secuencia de Bases , Secuencia Conservada , Humanos , Datos de Secuencia Molecular
5.
J Natl Cancer Inst ; 116(3): 434-444, 2024 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-38013591

RESUMEN

BACKGROUND: Studies of sleep and prostate cancer are almost entirely based on self-report, with limited research using actigraphy. Our goal was to evaluate actigraphy-measured sleep and prostate cancer and to expand on findings from prior studies of self-reported sleep. METHODS: We prospectively examined 34 260 men without a history of prostate cancer in the UK Biobank. Sleep characteristics were measured over 7 days using actigraphy. We calculated sleep duration, onset, midpoint, wake-up time, social jetlag (difference in weekend-weekday sleep midpoints), sleep efficiency (percentage of time spent asleep between onset and wake-up time), and wakefulness after sleep onset. Cox proportional hazards models were used to estimate covariate-adjusted hazards ratios (HRs) and 95% confidence intervals (CIs). RESULTS: Over 7.6 years, 1152 men were diagnosed with prostate cancer. Sleep duration was not associated with prostate cancer risk. Sleep midpoint earlier than 4:00 am was not associated with prostate cancer risk, though sleep midpoint of 5:00 am or later was suggestively associated with lower prostate cancer risk but had limited precision (earlier than 4:00 am vs 4:00-4:59 am HR = 1.00, 95% CI = 0.87 to 1.16; 5:00 am or later vs 4:00-4:59 am HR = 0.79, 95% CI = 0.57 to 1.10). Social jetlag was not associated with greater prostate cancer risk (1 to <2 hours vs <1 hour HR = 1.06, 95% CI = 0.89 to 1.25; ≥2 hours vs <1 hour HR = 0.90, 95% CI = 0.65 to 1.26). Compared with men who averaged less than 30 minutes of wakefulness after sleep onset per day, men with 60 minutes or more had a higher risk of prostate cancer (HR = 1.20, 95% CI = 1.00 to 1.43). CONCLUSIONS: Of the sleep characteristics studied, higher wakefulness after sleep onset-a measure of poor sleep quality-was associated with greater prostate cancer risk. Replication of our findings between wakefulness after sleep onset and prostate cancer are warranted.


Asunto(s)
Actigrafía , Neoplasias de la Próstata , Masculino , Humanos , Biobanco del Reino Unido , Bancos de Muestras Biológicas , Sueño , Neoplasias de la Próstata/epidemiología
6.
Ann Work Expo Health ; 67(5): 663-672, 2023 06 06.
Artículo en Inglés | MEDLINE | ID: mdl-36734402

RESUMEN

OBJECTIVES: Automatic job coding tools were developed to reduce the laborious task of manually assigning job codes based on free-text job descriptions in census and survey data sources, including large occupational health studies. The objective of this study is to provide a case study of comparative performance of job coding and JEM (Job-Exposure Matrix)-assigned exposures agreement using existing coding tools. METHODS: We compared three automatic job coding tools [AUTONOC, CASCOT (Computer-Assisted Structured Coding Tool), and LabourR], which were selected based on availability, coding of English free-text into coding systems closely related to the 1988 version of the International Standard Classification of Occupations (ISCO-88), and capability to perform batch coding. We used manually coded job histories from the AsiaLymph case-control study that were translated into English prior to auto-coding to assess their performance. We applied two general population JEMs to assess agreement at exposure level. Percent agreement and PABAK (Prevalence-Adjusted Bias-Adjusted Kappa) were used to compare the agreement of results from manual coders and automatic coding tools. RESULTS: The coding per cent agreement among the three tools ranged from 17.7 to 26.0% for exact matches at the most detailed 4-digit ISCO-88 level. The agreement was better at a more general level of job coding (e.g. 43.8-58.1% in 1-digit ISCO-88), and in exposure assignments (median values of PABAK coefficient ranging 0.69-0.78 across 12 JEM-assigned exposures). Based on our testing data, CASCOT was found to outperform others in terms of better agreement in both job coding (26% 4-digit agreement) and exposure assignment (median kappa 0.61). CONCLUSIONS: In this study, we observed that agreement on job coding was generally low for the three tools but noted a higher degree of agreement in assigned exposures. The results indicate the need for study-specific evaluations prior to their automatic use in general population studies, as well as improvements in the evaluated automatic coding tools.


Asunto(s)
Perfil Laboral , Exposición Profesional , Humanos , Estudios de Casos y Controles , Ocupaciones , Encuestas y Cuestionarios
7.
Ann Work Expo Health ; 67(6): 772-783, 2023 07 06.
Artículo en Inglés | MEDLINE | ID: mdl-37071789

RESUMEN

OBJECTIVES: Computer-assisted coding of job descriptions to standardized occupational classification codes facilitates evaluating occupational risk factors in epidemiologic studies by reducing the number of jobs needing expert coding. We evaluated the performance of the 2nd version of SOCcer, a computerized algorithm designed to code free-text job descriptions to US SOC-2010 system based on free-text job titles and work tasks, to evaluate its accuracy. METHODS: SOCcer v2 was updated by expanding the training data to include jobs from several epidemiologic studies and revising the algorithm to account for nonlinearity and incorporate interactions. We evaluated the agreement between codes assigned by experts and the highest scoring code (a measure of confidence in the algorithm-predicted assignment) from SOCcer v1 and v2 in 14,714 jobs from three epidemiology studies. We also linked exposure estimates for 258 agents in the job-exposure matrix CANJEM to the expert and SOCcer v2-assigned codes and compared those estimates using kappa and intraclass correlation coefficients. Analyses were stratified by SOCcer score, score distance between the top two scoring codes from SOCcer, and features from CANJEM. RESULTS: SOCcer's v2 agreement at the 6-digit level was 50%, compared to 44% in v1, and was similar for the three studies (38%-45%). Overall agreement for v2 at the 2-, 3-, and 5-digit was 73%, 63%, and 56%, respectively. For v2, median ICCs for the probability and intensity metrics were 0.67 (IQR 0.59-0.74) and 0.56 (IQR 0.50-0.60), respectively. The agreement between the expert and SOCcer assigned codes linearly increased with SOCcer score. The agreement also improved when the top two scoring codes had larger differences in score. CONCLUSIONS: Overall agreement with SOCcer v2 applied to job descriptions from North American epidemiologic studies was similar to the agreement usually observed between two experts. SOCcer's score predicted agreement with experts and can be used to prioritize jobs for expert review.


Asunto(s)
Exposición Profesional , Fútbol , Humanos , Perfil Laboral , Exposición Profesional/análisis , Estudios Epidemiológicos , Algoritmos
8.
Artículo en Inglés | MEDLINE | ID: mdl-37350888

RESUMEN

Motivation: Epidemiological studies face two important challenges: the need to ingest ever more complex data types, and mounting concerns about participant privacy and data governance. These two challenges are compounded by the expectation that data infrastructure will eventually need to facilitate cross-registration of participants by multiple epidemiological studies. Implementation: The portable web-service epiDonate was developed using the serverless model known as FaaS (Function-as-a-Service). The reference implementation uses nodejs. The implementation relies on a simple tokenization scheme, mediated by a public API, that a) distinguishes admin from participant roles, with b) extensible permission configuration operating a read/write structure. General Features: The critical design feature of epiDonate is the absence of business logic on the server-side (the web service). The simplicity removes the need to customize virtual machines and enables ecosystems of multiple web Applications backed by one or more data donation deployments. Availability: https://episphere.github.io/donate.

9.
Biochem Biophys Res Commun ; 417(4): 1164-9, 2012 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-22226962

RESUMEN

We have previously observed that all known HIV-1 broadly neutralizing antibodies (bnAbs) are highly divergent from germline antibodies in contrast to bnAbs against Hendra virus, Nipah virus and SARS coronavirus (SARS CoV). We have hypothesized that because the germline antibodies are so different from the mature HIV-1-specific bnAbs they may not bind the epitopes of the mature antibodies and provided the first evidence to support this hypothesis by using individual putative germline-like predecessor antibodies. To further validate the hypothesis and understand initial immune responses to different viruses, two phage-displayed human cord blood-derived IgM libraries were constructed which contained mostly germline antibodies or antibodies with very low level of somatic hypermutations. They were panned against different HIV-1 envelope glycoproteins (Envs), SARS CoV protein receptor-binding domain (RBD), and soluble Hendra virus G protein (sG). Despite a high sequence and combinatorial diversity observed in the cord blood-derived IgM antibody repertoire, no enrichment for binders of Envs was observed in contrast to considerable specific enrichments produced with panning against RBD and sG; one of the selected monoclonal antibodies (against the RBD) was of high (nM) affinity with only few somatic mutations. These results further support and expand our initial hypothesis for fundamental differences in immune responses leading to elicitation of bnAbs against HIV-1 compared to SARS CoV and Hendra virus. HIV-1 uses a strategy to minimize or eliminate strong binding of germline antibodies to its Env; in contrast, SARS CoV and Hendra virus, and perhaps other viruses causing acute infections, can bind germline antibody or minimally somatically mutated antibodies with relatively high affinity which could be one of the reasons for the success of sG and RBD as vaccine immunogens.


Asunto(s)
Inmunidad Adaptativa , Anticuerpos Monoclonales/inmunología , Anticuerpos Monoclonales/aislamiento & purificación , Anticuerpos Neutralizantes/inmunología , Glicoproteínas/inmunología , VIH-1/inmunología , Proteínas del Envoltorio Viral/inmunología , Secuencia de Aminoácidos , Anticuerpos Neutralizantes/genética , Sangre Fetal/inmunología , Virus Hendra/inmunología , Humanos , Datos de Secuencia Molecular , Biblioteca de Péptidos , Estructura Terciaria de Proteína , Coronavirus Relacionado al Síndrome Respiratorio Agudo Severo/inmunología
10.
Nat Commun ; 13(1): 5628, 2022 09 26.
Artículo en Inglés | MEDLINE | ID: mdl-36163250

RESUMEN

After spinal cord injury, tissue distal to the lesion contains undamaged cells that could support or augment recovery. Targeting these cells requires a clearer understanding of their injury responses and capacity for repair. Here, we use single nucleus RNA sequencing to profile how each cell type in the lumbar spinal cord changes after a thoracic injury in mice. We present an atlas of these dynamic responses across dozens of cell types in the acute, subacute, and chronically injured spinal cord. Using this resource, we find rare spinal neurons that express a signature of regeneration in response to injury, including a major population that represent spinocerebellar projection neurons. We characterize these cells anatomically and observed axonal sparing, outgrowth, and remodeling in the spinal cord and cerebellum. Together, this work provides a key resource for studying cellular responses to injury and uncovers the spontaneous plasticity of spinocerebellar neurons, uncovering a potential candidate for targeted therapy.


Asunto(s)
Traumatismos de la Médula Espinal , Animales , Axones/metabolismo , Cerebelo/metabolismo , Ratones , Regeneración Nerviosa/fisiología , Neuronas/metabolismo , Médula Espinal/metabolismo , Traumatismos de la Médula Espinal/patología
11.
Blood ; 113(16): 3706-15, 2009 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-19023113

RESUMEN

Subjects with X-linked hyper-IgM syndrome (X-HIgM) have a markedly reduced frequency of CD27(+) memory B cells, and their Ig genes have a low level of somatic hypermutation (SHM). To analyze the nature of SHM in X-HIgM, we sequenced 209 nonproductive and 926 productive Ig heavy chain genes. In nonproductive rearrangements that were not subjected to selection, as well as productive rearrangements, most of the mutations were within targeted RGYW, WRCY, WA, or TW motifs (R = purine, Y = pyrimidine, and W = A or T). However, there was significantly decreased targeting of the hypermutable G in RGYW motifs. Moreover, the ratio of transitions to transversions was markedly increased compared with normal. Microarray analysis documented that specific genes involved in SHM, including activation-induced cytidine deaminase (AICDA) and uracil-DNA glycosylase (UNG2), were up-regulated in normal germinal center (GC) B cells, but not induced by CD40 ligation. Similar results were obtained from light chain rearrangements. These results indicate that in the absence of CD40-CD154 interactions, there is a marked reduction in SHM and, specifically, mutations of AICDA-targeted G residues in RGYW motifs along with a decrease in transversions normally related to UNG2 activity.


Asunto(s)
Linfocitos B/enzimología , Citidina Desaminasa/biosíntesis , ADN Glicosilasas/biosíntesis , Regulación Enzimológica de la Expresión Génica/genética , Síndrome de Inmunodeficiencia con Hiper-IgM Tipo 1/genética , Cadenas Pesadas de Inmunoglobulina/genética , Hipermutación Somática de Inmunoglobulina/genética , Adolescente , Adulto , Linfocitos B/inmunología , Antígenos CD40/genética , Antígenos CD40/inmunología , Antígenos CD40/metabolismo , Ligando de CD40/genética , Ligando de CD40/inmunología , Ligando de CD40/metabolismo , Niño , Citidina Desaminasa/genética , Citidina Desaminasa/inmunología , ADN Glicosilasas/genética , ADN Glicosilasas/inmunología , Análisis Mutacional de ADN , Regulación Enzimológica de la Expresión Génica/inmunología , Centro Germinal/enzimología , Centro Germinal/inmunología , Humanos , Síndrome de Inmunodeficiencia con Hiper-IgM Tipo 1/enzimología , Síndrome de Inmunodeficiencia con Hiper-IgM Tipo 1/inmunología , Cadenas Pesadas de Inmunoglobulina/inmunología , Recubrimiento Inmunológico/genética , Recubrimiento Inmunológico/inmunología , Memoria Inmunológica/genética , Masculino , Mutación , Hipermutación Somática de Inmunoglobulina/inmunología , Regulación hacia Arriba/genética , Regulación hacia Arriba/inmunología
12.
J Expo Sci Environ Epidemiol ; 31(6): 1047-1056, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34006962

RESUMEN

BACKGROUND: Most methods for treating left-censored data assume the analyte is present but not quantified. Biased estimates may result if the analyte is absent such that the unobserved data represents a mixed exposure distribution with an unknown proportion clustered at zero. OBJECTIVE: We used semi-continuous models to identify time and industry trends in 52,457 OSHA inspection lead sample results. METHOD: The first component of the semi-continuous model predicted the probability of detecting concentrations ≥ 0.007 mg/m3 (highest estimated detection limit, 62% of measurements). The second component predicted the median concentration of measurements ≥ 0.007 mg/m3. Both components included a random-effect for industry and fixed-effects for year, industry group, analytical method, and other variables. We used the two components together to predict median industry- and time-specific lead concentrations. RESULTS: The probabilities of detectable concentrations and the median detected concentrations decreased with year; both were also lower for measurements analyzed for multiple (vs. one) metals and for those analyzed by inductively-coupled plasma (vs. atomic absorption spectroscopy). The covariance was 0.30 (standard error = 0.06), confirming the two components were correlated. SIGNIFICANCE: We identified determinants of exposure in data with over 60% left-censored, while accounting for correlated relationships and without assuming a distribution for the censored data.


Asunto(s)
Modelos Estadísticos , Exposición Profesional , Humanos , Industrias , Plomo , Exposición Profesional/análisis
13.
Nat Commun ; 12(1): 5722, 2021 09 29.
Artículo en Inglés | MEDLINE | ID: mdl-34588430

RESUMEN

Single-cell RNA sequencing data can unveil the molecular diversity of cell types. Cell type atlases of the mouse spinal cord have been published in recent years but have not been integrated together. Here, we generate an atlas of spinal cell types based on single-cell transcriptomic data, unifying the available datasets into a common reference framework. We report a hierarchical structure of postnatal cell type relationships, with location providing the highest level of organization, then neurotransmitter status, family, and finally, dozens of refined populations. We validate a combinatorial marker code for each neuronal cell type and map their spatial distributions in the adult spinal cord. We also show complex lineage relationships among postnatal cell types. Additionally, we develop an open-source cell type classifier, SeqSeek, to facilitate the standardization of cell type identification. This work provides an integrated view of spinal cell types, their gene expression signatures, and their molecular organization.


Asunto(s)
Neuronas/clasificación , Médula Espinal/citología , Transcriptoma , Animales , Atlas como Asunto , Núcleo Celular/genética , Conjuntos de Datos como Asunto , Ratones , Neuronas/citología , RNA-Seq , Análisis de la Célula Individual , Análisis Espacial , Médula Espinal/crecimiento & desarrollo
16.
Artículo en Inglés | MEDLINE | ID: mdl-25221787

RESUMEN

Mapping job titles to standardized occupation classification (SOC) codes is an important step in evaluating changes in health risks over time as measured in inspection databases. However, manual SOC coding is cost prohibitive for very large studies. Computer based SOC coding systems can improve the efficiency of incorporating occupational risk factors into large-scale epidemiological studies. We present a novel method of mapping verbatim job titles to SOC codes using a large table of prior knowledge available in the public domain that included detailed description of the tasks and activities and their synonyms relevant to each SOC code. Job titles are compared to our knowledge base to find the closest matching SOC code. A soft Jaccard index is used to measure the similarity between a previously unseen job title and the knowledge base. Additional information such as standardized industrial codes can be incorporated to improve the SOC code determination by providing additional context to break ties in matches.

17.
J Immunol ; 172(11): 6790-802, 2004 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-15153497

RESUMEN

We analyzed 77 nonproductive and 574 productive human V(H)DJ(H) rearrangements with a newly developed program, JOINSOLVER. In the productive repertoire, the H chain complementarity determining region 3 (CDR3(H)) was significantly shorter (46.7 +/- 0.5 nucleotides) than in the nonproductive repertoire (53.8 +/- 1.9 nucleotides) because of the tendency to select rearrangements with less TdT activity and shorter D segments. Using criteria established by Monte Carlo simulations, D segments could be identified in 71.4% of nonproductive and 64.4% of productive rearrangements, with a mean of 17.6 +/- 0.7 and 14.6 +/- 0.2 retained germline nucleotides, respectively. Eight of 27 D segments were used more frequently than expected in the nonproductive repertoire, whereas 3 D segments were positively selected and 3 were negatively selected, indicating that both molecular mechanisms and selection biased the D segment usage. There was no bias for D segment reading frame (RF) use in the nonproductive repertoire, whereas negative selection of the RFs encoding stop codons and positive selection of RF2 that frequently encodes hydrophilic amino acids were noted in the productive repertoire. Except for serine, there was no consistent selection or expression of hydrophilic amino acids. A bias toward the pairing of 5' D segments with 3' J(H) segments was observed in the nonproductive but not the productive repertoire, whereas V(H) usage was random. Rearrangements using inverted D segments, DIR family segments, chromosome 15 D segments and multiple D segments were found infrequently. Analysis of the human CDR3(H) with JOINSOLVER has provided comprehensive information on the influences that shape this important Ag binding region of V(H) chains.


Asunto(s)
Regiones Determinantes de Complementariedad/química , Cadenas Pesadas de Inmunoglobulina/química , Región de Unión de la Inmunoglobulina/química , Algoritmos , Secuencia de Aminoácidos , Aminoácidos/análisis , Secuencia de Bases , Regiones Determinantes de Complementariedad/análisis , ADN Nucleotidilexotransferasa/metabolismo , Reordenamiento Génico , Humanos , Cadenas Pesadas de Inmunoglobulina/genética , Región de Unión de la Inmunoglobulina/genética , Datos de Secuencia Molecular , Método de Montecarlo
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