BUB1B monoallelic germline variants contribute to prostate cancer predisposition by triggering chromosomal instability.

BACKGROUND: Prostate cancer (PrCa) is the most frequently diagnosed cancer in men. Variants in known moderate- to high-penetrance genes explain less than 5% of the cases arising at early-onset (< 56 years) and/or with familial aggregation of the disease. Considering that BubR1 is an essential component of the mitotic spindle assembly checkpoint, we hypothesized that monoallelic BUB1B variants could be sufficient to fuel chromosomal instability (CIN), potentially triggering (prostate) carcinogenesis. METHODS: To unveil BUB1B as a new PrCa predisposing gene, we performed targeted next-generation sequencing in germline DNA from 462 early-onset/familial PrCa patients and 1,416 cancer patients fulfilling criteria for genetic testing for other hereditary cancer syndromes. To explore the pan-cancer role of BUB1B, we used in silico BubR1 molecular modeling, in vitro gene-editing, and ex vivo patients' tumors and peripheral blood lymphocytes. RESULTS: Rare BUB1B variants were found in ~ 1.9% of the early-onset/familial PrCa cases and in ~ 0.6% of other cancer patients fulfilling criteria for hereditary disease. We further show that BUB1B variants lead to decreased BubR1 expression and/or stability, which promotes increased premature chromatid separation and, consequently, triggers CIN, driving resistance to Taxol-based therapies. CONCLUSIONS: Our study shows that different BUB1B variants may uncover a trigger for CIN-driven carcinogenesis, supporting the role of BUB1B as a (pan)-cancer predisposing gene with potential impact on genetic counseling and treatment decision-making.

Lack of association of impaired upper airway sensation with the presence or absence of obstructive sleep apnoea or chronic rhinosinusitis in World Trade Center responders.

OBJECTIVE: Examine sensory function of the upper airway in four groups of subjects recruited from the World Trade Centre General Responder Cohort (WTCGRC), with/without obstructive sleep apnoea (OSA), and with/without chronic rhinosinusitis (CRS). METHODS: Upper airway sensory function was determined using 2-point discrimination (2-PD) and vibration threshold (VT) in 163 WTCGRC subjects with both OSA and CRS (cases), OSA or CRS alone and without OSA or CRS (controls). Presence of OSA was determined from clinical sleep studies or home sleep testing. Presence of CRS was determined by nasal symptom questionnaire. The relationship between the presence of OSA and CRS and upper airway sensory impairment was assessed using linear regression analysis with each of 2PD and VT sensory threshold values as the dependent variable; OSA, CRS and their interaction were the independent variables. Age, gender and body mass index were covariates in the statistical model. The primary analysis was comparison of OSA+CRS versus controls (no OSA and no CRS) evaluated by linear contrasts. RESULTS: There were no differences in 2-PD or VT in those with OSA+CRS, OSA and CRS alone or controls. However, both 2-PD and VT were significantly higher in the WTCGRC controls compared with values seen in historical controls using the same methodology (median 2-PD 13.0; CI (11.0 to 13.5) vs 10.5; CI (8 to 11); VT: mean±SEM (9.3±0.6 vs 2.2±0.1)). CONCLUSION: While no differences were found in upper airway sensation between cases of OSA and CRS versus controls in the WTGRC population, there was evidence of impaired upper airway sensation in the WTGRC overall.

Comparison of COVID-19 Symptoms in Correctional Health Care Workers During the Initial and Omicron Surges.

There is a dearth of medical literature that characterizes the experience of correctional health care workers (HCWs) during the COVID-19 pandemic. We performed a retrospective chart review of the results of an ongoing universal SARS-CoV-2 testing program for New Jersey correctional system HCWs and describe their presenting symptoms, perceived exposure, and demographic characteristics during the initial (March 15, 2020, to August 31, 2020) and Omicron (March 1, 2022, to August 31, 2022) COVID-19 surges. Analysis included 123 eligible records. In both surges, nurses had a high proportion of infections and cough was the most commonly reported symptom. Fever was more than twice as commonly reported in the initial surge. During the Omicron surge, nasal symptoms predominated (39.5% [95% CI: 28.4-51.4]) compared with the initial surge (8.5% [95% CI: 2.4-20.4]). Perceived exposure source was predominantly work related during the initial surge and multiple other sources of exposure were identified during the Omicron surge. Ninety-six percent of HCWs received a COVID-19 booster shot by February 2022. The reinfection rate was less than 10% for our initial cohort. Presenting symptoms correlated with the circulating variant. Mass vaccination of staff, the lower virulence of the Omicron variant, and possibly prior infection likely contributed to the milder illness experienced during the Omicron surge.

Real-World Effectiveness of Portable Air Cleaners in Reducing Home Particulate Matter Concentrations.

Portable air cleaners (PACs) equipped with HEPA filters are gaining attention as cost-effective means of decreasing indoor particulate matter (PM) air pollutants and airborne viruses. However, the performance of PACs in naturalistic settings and spaces beyond the room containing the PAC is not well characterized. We conducted a single-blinded randomized cross-over interventional study between November 2020 and May 2021 in the homes of adults who tested positive for COVID-19. The intervention was air filtration with PAC operated with the HEPA filter set installed ("filter" condition) versus removed ("sham" condition, i.e., control). Sampling was performed in 29 homes for two consecutive 24-hour periods in the primary room (containing the PAC) and a secondary room. PAC effectiveness, calculated as reductions in overall mean PM2.5 and PM10 concentrations during the filter condition, were for the primary rooms 78.8% and 63.9% (n = 23), respectively, and for the secondary rooms 57.9% and 60.4% (n = 22), respectively. When a central air handler (CAH) was reported to be in use, filter-associated reductions of PM were statistically significant during the day (06:00-22:00) and night (22:01-05:59) in the primary rooms but only during the day in the secondary rooms. Our study adds to the literature evaluating the real-world effects of PACs on a secondary room and considering the impact of central air systems on PAC performance.

Implementation of upfront DPYD genotyping with a low-cost and high-throughput assay to guide fluoropyrimidine treatment in cancer patients.

OBJECTIVES: Genetic variants in the dihydropyrimidine dehydrogenase (DPYD ) gene are associated with reduced dihydropyrimidine dehydrogenase enzyme activity and can cause severe fluoropyrimidine-related toxicity. We assessed the frequency of the four most common and well-established DPYD variants associated with fluoropyrimidine toxicity and implemented a relatively low-cost and high-throughput genotyping assay for their detection. METHODS: This study includes 457 patients that were genotyped for the DPYD c.1129-5923C>G, c.1679T>G, c.1905 + 1G>A and c.2846A>T variants, either by Sanger sequencing or kompetitive allele specific PCR (KASP) technology. Of these, 172 patients presented toxicity during treatment with fluoropyrimidines (post-treatment group), and 285 were tested before treatment (pretreatment group). RESULTS: Heterozygous DPYD variants were identified in 7.4% of the entire series of 457 patients, being the c.2846A>T the most frequent variant. In the post-treatment group, 15.7% of the patients presented DPYD variants, whereas only 2.5% of the patients in the pretreatment group presented a variant. The KASP assays designed in this study presented 100% genotype concordance with the results obtained by Sanger sequencing. CONCLUSIONS: The combined assessment of the four DPYD variants in our population increases the identification of patients at high risk for developing fluoropyrimidine toxicity, supporting the upfront routine implementation of DPYD variant genotyping. Furthermore, the KASP genotyping assay described in this study presents a rapid turnaround time and relatively low cost, making upfront DPYD screening feasible in clinical practice.

Incidence and Predictors of COVID-19 Infection in Prison Healthcare Workers.

OBJECTIVE: The aim of the study is to assess the predictors of SARS-CoV-2 infection among correctional healthcare workers (HCWs). METHODS: We conducted a retrospective chart review to describe the demographic and workplace characteristics of New Jersey correctional HCWs between March 15, 2020, and August 31, 2020, using univariate and multivariable analysis. RESULTS: Among 822 HCWs, patient-facing staff had the highest incidence of infection (7.2%). Associated risk factors include being Black and working in a maximum-security prison. There were few statistically significant findings due to small total numbers ( n = 47) that tested positive. CONCLUSIONS: Correctional HCWs' challenging work environment creates unique risk factors for infection with the SARS-CoV-2 virus. Administrative measures taken by the department of corrections may have a significant role in curbing the spread of infection. The findings can help focus preventive measures for reducing the spread of COVID-19 in this unique population.

Portable air cleaners and residential exposure to SARS-CoV-2 aerosols: A real-world study.

Individuals with COVID-19 who do not require hospitalization are instructed to self-isolate in their residences. Due to high secondary infection rates in household members, there is a need to understand airborne transmission of SARS-CoV-2 within residences. We report the first naturalistic intervention study suggesting a reduction of such transmission risk using portable air cleaners (PACs) with HEPA filters. Seventeen individuals with newly diagnosed COVID-19 infection completed this single-blind, crossover, randomized study. Total and size-fractionated aerosol samples were collected simultaneously in the self-isolation room with the PAC (primary) and another room (secondary) for two consecutive 24-h periods, one period with HEPA filtration and the other with the filter removed (sham). Seven out of sixteen (44%) air samples in primary rooms were positive for SARS-CoV-2 RNA during the sham period. With the PAC operated at its lowest setting (clean air delivery rate [CADR] = 263 cfm) to minimize noise, positive aerosol samples decreased to four out of sixteen residences (25%; p = 0.229). A slight decrease in positive aerosol samples was also observed in the secondary room. As the world confronts both new variants and limited vaccination rates, our study supports this practical intervention to reduce the presence of viral aerosols in a real-world setting.

Compensatory effect of fibrinogen in a patient with bone marrow aplasia, septic shock, and severe thrombocytopenia guided by thromboelastometry: a case report. / Efeito compensatório do fibrinogênio em paciente com aplasia de medula óssea, choque séptico e trombocitopenia grave guiado por tromboelastometria: relato de caso.

Platelet transfusion is a common practice to prevent spontaneous bleeding or bleeding due to invasive procedures. Transfusion of allogeneic blood components is associated with increased mortality and a worse clinical outcome. The clot strength is assessed by thromboelastometry and determined by the interaction between platelets and fibrinogen. The compensatory effect of high levels of fibrinogen on clot strength in patients with thrombocytopenia has been demonstrated in different clinical settings including sepsis. We report the case of a patient with severe thrombocytopenia whose thromboelastometry showed clot strength that was compensated for by the increase in plasma fibrinogen levels as an acute phase reactant of septic patients. Here, we report a case of a 62-year-old female diagnosed with bone marrow aplasia admitted in the intensive care unit with septic shock and severe thrombocytopenia. During the first 24 hours in the intensive care unit, she presented acute respiratory insufficiency and circulatory shock. The use of invasive mechanical ventilation and norepinephrine was required. Her chest X-ray showed bilateral lung injury. Thus, bronchoscopy with bronchoalveolar lavage was requested. Thromboelastometry was performed and resulted in a normal coagulable profile. Despite severe thrombocytopenia (1,000/mm3), fibrinogen levels were increased (1,050mg/dL) due to septic shock. Bronchoscopy was performed without any active or further bleeding. Here, we report the use of thromboelastometry in the diagnosis of coagulation disorders, preventing unnecessary prophylactic platelet transfusion.

A transfusão de concentrado de plaquetas é prática comum para prevenção de sangramento espontâneo ou decorrente de procedimentos invasivos; sabe-se que a transfusão de componentes alogênicos do sangue se associa a aumento da mortalidade e piora do desfecho clínico. A força do coágulo é avaliada por meio da tromboelastometria rotacional e determinada pela interação entre plaquetas e fibrinogênio. O efeito compensatório do incremento na concentração sérica de fibrinogênio na força do coágulo, em pacientes com trombocitopenia, tem sido demonstrado em diferentes contextos clínicos, incluindo sepse. Relatamos o caso de uma paciente com trombocitopenia grave, cujo resultado da tromboelastometria rotacional demonstrou efeito compensatório na força do coágulo determinada pelos níveis plasmáticos aumentados de fibrinogênio como reagente de fase aguda em pacientes sépticos. Relatamos o caso de uma paciente de 62 anos com diagnóstico de aplasia de medula óssea admitida a uma unidade de terapia intensiva com choque séptico e trombocitopenia grave. Nas primeiras 24 horas na unidade de terapia intensiva, ela apresentou quadro clínico de insuficiência respiratória aguda e choque. Foi necessário utilizar ventilação mecânica invasiva e fármaco vasoativo. A radiografia de tórax mostrou padrão de lesão pulmonar bilateral. Desta forma, foi solicitada broncoscopia com lavagem broncoalveolar para investigação diagnóstica. Conduziu-se uma tromboelastometria rotacional, e seu resultado mostrou perfil de coagulação normal. Apesar da trombocitopenia grave (1.000/mm3), os níveis de fibrinogênio aumentaram (1.050mg/dL) devido ao choque séptico. A broncoscopia foi realizada sem que subsequentemente ocorresse sangramento ativo. Este caso relata o uso da tromboelastometria como ferramenta diagnóstica em distúrbios da coagulação de pacientes graves, permitindo prevenir o uso desnecessário de transfusões profiláticas de concentrado de plaquetas.

Efeito compensatório do fibrinogênio em paciente com aplasia de medula óssea, choque séptico e trombocitopenia grave guiado por tromboelastometria: relato de caso / Compensatory effect of fibrinogen in a patient with bone marrow aplasia, septic shock, and severe thrombocytopenia guided by thromboelastometry: a case report

RESUMO A transfusão de concentrado de plaquetas é prática comum para prevenção de sangramento espontâneo ou decorrente de procedimentos invasivos; sabe-se que a transfusão de componentes alogênicos do sangue se associa a aumento da mortalidade e piora do desfecho clínico. A força do coágulo é avaliada por meio da tromboelastometria rotacional e determinada pela interação entre plaquetas e fibrinogênio. O efeito compensatório do incremento na concentração sérica de fibrinogênio na força do coágulo, em pacientes com trombocitopenia, tem sido demonstrado em diferentes contextos clínicos, incluindo sepse. Relatamos o caso de uma paciente com trombocitopenia grave, cujo resultado da tromboelastometria rotacional demonstrou efeito compensatório na força do coágulo determinada pelos níveis plasmáticos aumentados de fibrinogênio como reagente de fase aguda em pacientes sépticos. Relatamos o caso de uma paciente de 62 anos com diagnóstico de aplasia de medula óssea admitida a uma unidade de terapia intensiva com choque séptico e trombocitopenia grave. Nas primeiras 24 horas na unidade de terapia intensiva, ela apresentou quadro clínico de insuficiência respiratória aguda e choque. Foi necessário utilizar ventilação mecânica invasiva e fármaco vasoativo. A radiografia de tórax mostrou padrão de lesão pulmonar bilateral. Desta forma, foi solicitada broncoscopia com lavagem broncoalveolar para investigação diagnóstica. Conduziu-se uma tromboelastometria rotacional, e seu resultado mostrou perfil de coagulação normal. Apesar da trombocitopenia grave (1.000/mm3), os níveis de fibrinogênio aumentaram (1.050mg/dL) devido ao choque séptico. A broncoscopia foi realizada sem que subsequentemente ocorresse sangramento ativo. Este caso relata o uso da tromboelastometria como ferramenta diagnóstica em distúrbios da coagulação de pacientes graves, permitindo prevenir o uso desnecessário de transfusões profiláticas de concentrado de plaquetas.

ABSTRACT Platelet transfusion is a common practice to prevent spontaneous bleeding or bleeding due to invasive procedures. Transfusion of allogeneic blood components is associated with increased mortality and a worse clinical outcome. The clot strength is assessed by thromboelastometry and determined by the interaction between platelets and fibrinogen. The compensatory effect of high levels of fibrinogen on clot strength in patients with thrombocytopenia has been demonstrated in different clinical settings including sepsis. We report the case of a patient with severe thrombocytopenia whose thromboelastometry showed clot strength that was compensated for by the increase in plasma fibrinogen levels as an acute phase reactant of septic patients. Here, we report a case of a 62-year-old female diagnosed with bone marrow aplasia admitted in the intensive care unit with septic shock and severe thrombocytopenia. During the first 24 hours in the intensive care unit, she presented acute respiratory insufficiency and circulatory shock. The use of invasive mechanical ventilation and norepinephrine was required. Her chest X-ray showed bilateral lung injury. Thus, bronchoscopy with bronchoalveolar lavage was requested. Thromboelastometry was performed and resulted in a normal coagulable profile. Despite severe thrombocytopenia (1,000/mm3), fibrinogen levels were increased (1,050mg/dL) due to septic shock. Bronchoscopy was performed without any active or further bleeding. Here, we report the use of thromboelastometry in the diagnosis of coagulation disorders, preventing unnecessary prophylactic platelet transfusion.

The HIV oligonucleotide database (HIVoligoDB).

The human immunodeficiency virus (HIV) is associated with one of the most widespread infectious disease, the acquired immunodeficiency syndrome (AIDS). The development of antiretroviral drugs and methods for virus detection requires a comprehensive analysis of the HIV genomic diversity, particularly in the binding sites of oligonucleotides. Here, we describe a versatile online database (HIVoligoDB) with oligonucleotides selected for the diagnosis of HIV and treatment of AIDS. Currently, the database provides an interface for visualization, analysis and download of 380 HIV-1 and 65 HIV-2 oligonucleotides annotated according to curated reference genomes. The database also allows the selection of the most conserved HIV genomic regions for the development of molecular diagnostic assays and sequence-based candidate therapeutics. Database URL: http://portugene.com/HIVoligoDB.

Mitochondrial DNA variation of domestic sheep (Ovis aries) in Kenya.

The history of domestic sheep (Ovis aries) in Africa remains largely unknown. After being first introduced from the Near East, sheep gradually spread through the African continent with pastoral societies. The eastern part of Africa was important either for the first diffusion of sheep southward or for putative secondary introductions from the Arabian Peninsula or southern Asia. We analysed mitochondrial DNA control region sequences of 91 domestic sheep from Kenya and found a high diversity of matrilines from the widespread haplogroup B, whereas only a single individual from haplogroup A was detected. Our phylogeography analyses of more than 500 available mitochondrial DNA sequences also identified ancestral haplotypes that were probably first introduced in Africa and are now widely distributed. Moreover, we found no evidence of an admixture between East and West African sheep. The presence of shared haplotypes in eastern and ancient southern African sheep suggests the possible southward movement of sheep along the eastern part of Africa. Finally, we found no evidence of an extensive introduction of sheep from southern Asia into Africa via the Indian Ocean trade. The overall findings on the phylogeography of East African domestic sheep set the grounds for understanding the origin and subsequent movements of sheep in Africa. The richness of maternal lineages in Kenyan breeds is of prime importance for future conservation and breeding programmes.

Esterase polymorphism marking cultivars of Manihot esculenta, Crantz

Isoenzimas esterases foram usadas no presente estudo, para detectar polimorfismos específicos para diferentes substratos em vinte cultivares de Manihot esculenta, e para mostrar variações específicas de cultivares nesta espécie. Os diferentes cultivares de M. esculenta tem sido mantidos na coleção de germoplasma do Departamento de Agronomia da Universidade Estadual de Maringá (Maringá, PR), e foram provenientes de cultivares tradicionais coletados nas regiões sudoeste e noroeste do Estado. Foi necessário a utilização de uma solução de extração de proteínas relativamente mais complexa, para evidenciar um maior número de isoenzimas esterases. A similaridade entre os cultivares variou de 51 a 96%. Cultivares identificados pelo mesmo nome parecem ser bioquimicamente diferentes para as isoenzimas esterases. Os padrões eletroforéticos das isoesterases podem, portanto, serem usados para discriminar os cultivares que são identificados pelo mesmo nome, e para monitorar a propagação vegetativa dos cultivares mantidos na coleção de germoplasma. A análise das isoesterases pode também ser usada para evitar cruzamentos entre genótipos mais similares em programas de melhoramento.

Trauma ocular em crianças: um estudo epidemiológico na universidade federal de Uberlândia nos últimos cinco anos / Open-globe injuries in children: an epidemiological study at the federal university of Uberlândia in the last five years

Relatar a frequência, as causas, as condições da ocorrência e as complicações dos traumas oculares em crianças admitidas ao Hospital de Clínicas da Faculdade de Medicina da Universidade Federal de Uberlândia (HC-UFU). Método: Análise retrospectiva dos prontuários de 38 crianças (com até 15 anos de idade) que sofreram trauma ocular e foram atendidas no setor de emergência do HC-UFU no período de janeiro de 1996 a dezembro 2000. Os dados foram analisados usando o teste t-Student e o teste Qui-quadrado. Resultados: Os meninos foram acometidos aproximadamente 2.5 vezes mais que as meninas. A idade média foi de 8,70 ± 4,56 anos entre meninos e 7,00 ± 3,74 anos nas meninas. A média de segmento foi de 22,63 ± 20,99 meses. Foram encontrados 34 ferimentos penetrantes (89,5%), um ferimento perfurante (2,6%), um ruptura (2,6%) e dois casos com corpo estranho intraocular (CEIO) associado (5,3%), com acometimento corneano em 71.1% dos casos. Os acidentes domésticos foram a causa a mais comum de trauma. A melhor acuidade visual final corrigida encontrada foi melhor de 0,5 em 13,1% dos pacientes com acometimento corneano e 5,3% com acometimento escleral. Seis pacientes (15,8%) perderam completamente a visão do olho afetado. Conclusões: Os traumas oculares nas crianças permanecem um grave problema e continuam sendo uma causa importante de perda da visão. O lugar mais comum de ocorrência é em casa.

To report the frequency, causes, occurrence conditions and complications of eye injuries in children admitted in the Clinic Hospital of the Medical College of the Federal University of Uberlândia (HC-UFU). Method: Retrospective review of the records of 38 children (15 years of age or younger) that suffered penetrating injuries and were assisted at the HC-UFU emergency room from January 1996 through December 2000. Results: the male to female ratio was approximately 2.5:1. The mean age was 8.70 ± 4.56 years between boys and 7.00 ± 3.74 years in girls. We found 34 penetrating injuries (89.5%). Domestic accidents were the most common cause of injury. Six patients (15.8%) lost the vision of the injured eye completely. Conclusions: Serious eye injuries in children remain n a problem and the most common place for it occurs is the home and ocular trauma continues being an important cause of vision impairment.

Malate dehydrogenase isozyme patterns in cladophylls of a Opuntia ficus-indica Mill. (Cactaceae) clonal population - DOI: 10.4025/actascibiolsci.v25i1.2093 / Padrões de isozimas de malato desidrogenase em população clonal nos cladófilos de Opuntia ficus-indica Mill (Cactaceae) - DOI: 10.4025/actascibiolsci.v25i1.2093

Malate dehydrogenase (MDH) isozymes were used as biochemical markers to discriminate and cluster cladophylls of plants of one clonal population of the prickly pear, Opuntia ficus-indica (Cactaceae). The isozyme electrophoretic patterns obtained with MDH provided 8 isozymes and 5 different electrophoretic phenotypes. Similarity in cladophylls was estimated using Jaccards coefficient. This clonal population studied was founded by only one propagule, and after 50 years, it is likely to have been formed by asexual and sexual propagules. Since that differential expression of MDH isozymes could play a significant role in overall plant cell metabolism, we suggest that the cladophylls of prickly pear that were clustered together showing identity or higher similarity are specially a suitable source for industrial procedures of industrial extraction of commercial interest compounds because a same extraction protocols can be most quickly and easily standardized using genetically uniform materials. Electrophoretic patterns of MDH isozymes can be used as an effective tool for previously determine the genetic similarity in the cladophylls of O. ficus-indica plants

Isozimas de malato desidrogenase (MDH) foram usadas como marcadores moleculares para discriminar e agrupar cladófilos de plantas de uma população clonal de cactus da espécie Opuntia ficus-indica (Cactaceae), conhecida como palma. O padrão eletroforético obtido revelou 8 isozimas MDH e 5 fenótipos eletroforéticos diferentes. A similaridade entre os cladófilos foi estimada usando o coeficiente de similaridade de Jaccard. Essa população clonal estudada foi fundada por somente um propágulo e, após 50 anos, parece ser formada por propágulos assexuais e sexuais. Uma vez que a expressão diferencial de isozimas MDH pode ter um papel significante no metabolismo das células da planta, sugerimos que os cladófilos de palma que foram agrupados com os mais altos valores de similaridade são os mais adequados para serem utilizados em procedimentos de extração industrial de compostos de interesse comercial, porque um mesmo protocolo de extração pode ser mais rapidamente e facilmente padronizado quando se utiliza material geneticamente uniforme. O padrão eletroforético das isozimas MDH pode ser usado como uma ferramenta efetiva para uma análise prévia da similaridade genética entre os cladófilos das plantas de O. ficus-indica

Variaçöes circadianas diárias e semanais na morte súbita da doença de Chagas / Circadian Daily and Weekly Variations in Sudden Death Due to Chagas' Disease

PURPOSE--To determinate the circadian daily and weekly variations in the incidence of sudden death due to Chagas' disease. METHODS--In 50 chronic chagasic individuals with sudden death due to Chagas' disease and in 473 individuals with natural, not sudden death, we analyzed both the day of the week and the time of the death. Statistical tests were applied to determine the significance of the difference between proportions and averages. RESULTS--For the chagasic group the values indicated a highly significant excess of lethality for the period between 12 and 6pm. The occurrence of the sudden death was the same in the different days of the week for both groups. CONCLUSION--The observed results suggest that the sudden death associated with Chagas' disease has a circadian pattern with a vespertine peak. Weekly variations in the sudden death of chronic chagasic individuals were not detected