Unlocking the complete blood count as a risk stratification tool for breast cancer using machine learning: a large scale retrospective study.

Optimizing early breast cancer (BC) detection requires effective risk assessment tools. This retrospective study from Brazil showcases the efficacy of machine learning in discerning complex patterns within routine blood tests, presenting a globally accessible and cost-effective approach for risk evaluation. We analyzed complete blood count (CBC) tests from 396,848 women aged 40-70, who underwent breast imaging or biopsies within six months after their CBC test. Of these, 2861 (0.72%) were identified as cases: 1882 with BC confirmed by anatomopathological tests, and 979 with highly suspicious imaging (BI-RADS 5). The remaining 393,987 participants (99.28%), with BI-RADS 1 or 2 results, were classified as controls. The database was divided into modeling (including training and validation) and testing sets based on diagnostic certainty. The testing set comprised cases confirmed by anatomopathology and controls cancer-free for 4.5-6.5 years post-CBC. Our ridge regression model, incorporating neutrophil-lymphocyte ratio, red blood cells, and age, achieved an AUC of 0.64 (95% CI 0.64-0.65). We also demonstrate that these results are slightly better than those from a boosting machine learning model, LightGBM, plus having the benefit of being fully interpretable. Using the probabilistic output from this model, we divided the study population into four risk groups: high, moderate, average, and low risk, which obtained relative ratios of BC of 1.99, 1.32, 1.02, and 0.42, respectively. The aim of this stratification was to streamline prioritization, potentially improving the early detection of breast cancer, particularly in resource-limited environments. As a risk stratification tool, this model offers the potential for personalized breast cancer screening by prioritizing women based on their individual risk, thereby indicating a shift from a broad population strategy.

Impact of genetic background as a risk factor for atherosclerotic cardiovascular disease: A protocol for a nationwide genetic case-control (CV-GENES) study in Brazil.

Atherosclerotic Cardiovascular Disease (ASCVD) represents the leading cause of death worldwide, and individual screening should be based on behavioral, metabolic, and genetic profile derived from data collected in large population-based studies. Due to the polygenic nature of ASCVD, we aimed to assess the association of genomics with ASCVD risk and its impact on the occurrence of acute myocardial infarction, stroke, or peripheral artery thrombotic-ischemic events at population level. CardioVascular Genes (CV-GENES) is a nationwide, multicenter, 1:1 case-control study of 3,734 patients in Brazil. Inclusion criterion for cases is the first occurrence of one of the ASCVD events. Individuals without known ASCVD will be eligible as controls. A core lab will perform the genetic analyses through low-pass whole genome sequencing and whole exome sequencing. In order to estimate the independent association between genetic polymorphisms and ASCVD, a polygenic risk score (PRS) will be built through a hybrid approach including effect size of each Single Nucleotide Polymorphism (SNP), number of effect alleles observed, sample ploidy, total number of SNPs included in the PRS, and number of non-missing SNPs in the sample. In addition, the presence of pathogenic or likely pathogenic variants will be screened in 8 genes (ABCG5, ABCG8, APOB, APOE, LDLR, LDLRAP1, LIPA, PCSK9) associated with atherosclerosis. Multiple logistic regression will be applied to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI), and population attributable risks will be calculated. Clinical trial registration: This study is registered in clinicaltrials.gov (NCT05515653).

Prediction of SARS-CoV-2-positivity from million-scale complete blood counts using machine learning.

Background: The Complete Blood Count (CBC) is a commonly used low-cost test that measures white blood cells, red blood cells, and platelets in a person's blood. It is a useful tool to support medical decisions, as intrinsic variations of each analyte bring relevant insights regarding potential diseases. In this study, we aimed at developing machine learning models for COVID-19 diagnosis through CBCs, unlocking the predictive power of non-linear relationships between multiple blood analytes. Methods: We collected 809,254 CBCs and 1,088,385 RT-PCR tests for SARS-Cov-2, of which 21% (234,466) were positive, from 900,220 unique individuals. To properly screen COVID-19, we also collected 120,807 CBCs of 16,940 individuals who tested positive for other respiratory viruses. We proposed an ensemble procedure that combines machine learning models for different respiratory infections and analyzed the results in both the first and second waves of COVID-19 cases in Brazil. Results: We obtain a high-performance AUROC of 90 + % for validations in both scenarios. We show that models built solely of SARS-Cov-2 data are biased, performing poorly in the presence of infections due to other RNA respiratory viruses. Conclusions: We demonstrate the potential of a novel machine learning approach for COVID-19 diagnosis based on a CBC and show that aggregating information about other respiratory diseases was essential to guarantee robustness in the results. Given its versatile nature, low cost, and speed, we believe that our tool can be particularly useful in a variety of scenarios-both during the pandemic and after.

Evaluation of Volumetric Absorptive Microsampling and Mass Spectrometry Data-Independent Acquisition of Hemoglobin-Related Clinical Markers.

Data-independent acquisition (DIA) allows comprehensive proteome coverage, while it also potentially works as a unified protocol to determine a multitude of proteins found in blood. Because of its high specificity, mass spectrometry may greatly reduce the interference observed in other assays to evaluate blood markers. Here, we combined DIA with volumetric absorptive microsampling (VAMS) and automated proteomics sample processing in a platform to assess clinical markers. As a proof of concept, we evaluated two hemoglobin-related biomarkers: the glycated hemoglobin (HbA1c) and hemoglobin (Hb) variants. HbA1c by DIA showed good correlation with the reference method, but method imprecision did not meet the quality requirement for this biomarker. We developed a strategy to identify Hb variants based on a customized database combined with a workflow for DIA data extraction and rigorous peptide evaluation. Data are available via ProteomeXchange with identifier PXD029918.

Exome sequencing and targeted gene panels: a simulated comparison of diagnostic yield using data from 158 patients with rare diseases.

Next-generation sequencing (NGS) has altered clinical genetic testing by widening the access to molecular diagnosis of genetically determined rare diseases. However, physicians may face difficulties selecting the best diagnostic approach. Our goal is to estimate the rate of possible molecular diagnoses missed by different targeted gene panels using data from a cohort of patients with rare genetic diseases diagnosed with exome sequencing (ES). For this purpose, we simulated a comparison between different targeted gene panels and ES: the list of genes harboring clinically relevant variants from 158 patients was used to estimate the theoretical rate of diagnoses missed by NGS panels from 53 different NGS panels from eight different laboratories. Panels presented a mean rate of missed diagnoses of 64% (range 14%-100%) compared to ES, representing an average predicted sensitivity of 36%. Metabolic abnormalities represented the group with highest mean of missed diagnoses (86%), while seizure represented the group with lowest mean (46%). Focused gene panels are restricted in covering select sets of genes implicated in specific diseases and they may miss molecular diagnoses of rare diseases compared to ES. However, their role in genetic diagnosis remains important especially for well-known genetic diseases with established genetic locus heterogeneity.

Assessment of initial SARS-CoV-2 seroprevalence in the most affected districts in the municipality of São Paulo, Brazil.

BACKGROUND: São Paulo city has been one of the regions most affected by the COVID-19 pandemic in Brazil. Frequent asymptomatic and oligosymptomatic infections and poor access to diagnostic tests make serosurveys crucial to monitor the magnitude of the epidemic and to inform public health policies, such as vaccination plans. OBJECTIVES: To estimate, early in the epidemic, the seroprevalence of antibodies to SARS-CoV-2 in adults living in the six most affected districts in São Paulo city, and to assess potential associated risk factors. METHODS: This was a cross-sectional population-based survey of 1,152 households randomly selected from 72 census tracts. During the period May 4-12, 2020, 463 participants completed a questionnaire on sociodemographic characteristics and history of symptoms in the past two weeks, and provided a blood sample. Prevalence of SARS-CoV-2 antibodies was the outcome of interest and was estimated based on results of two immunoassays, Maglumi SARS-CoV-2 chemiluminescence assay Immunoglobulin (Ig) M (IgM) and IgG, and Roche electrochemiluminescence assay total Ig. Serum samples reactive to either assay were considered positive. RESULTS: Weighted overall seroprevalence was 6% (95%CI 3.9-8.3%). No association was observed between seropositivity and sex, age group or education level. Participants who reported black and brown skin color showed a 2.7 fold higher prevalence than people with white skin (p = 0.007). Among the 30 seropositive individuals, 14 (46.6%) reported no COVID-19 compatible symptoms in the past two weeks. CONCLUSION: This study represents the first assessment of SARS-CoV-2 seroprevalence in the city of São Paulo and 6% is the baseline estimate of a series of population-based seroprevalence surveys. Serological screening using sound serological assays is the key tool to monitoring temporal and geographic changes in the spread of the virus through an important epicenter of the COVID-19 pandemic in Brazil. Ultimately, it may inform prevention and control efforts.

Frequency of carriers for rare recessive Mendelian diseases in a Brazilian cohort of 320 patients.

Several Mendelian disorders follow an autosomal recessive inheritance pattern. Epidemiological information on many inherited disorders may be useful to guide health policies for rare diseases, but it is often inadequate, particularly in developing countries. We aimed to calculate the carrier frequencies of rare autosomal recessive Mendelian diseases in a cohort of Brazilian patients using whole exome sequencing (WES). We reviewed the molecular findings of WES from 320 symptomatic patients who had carrier status for recessive diseases. Using the Hardy-Weinberg equation, we estimated recessive disease frequencies (q2 ) considering the respective carrier frequencies (2pq) observed in our study. We calculated the sensitivity of carrier screening tests based on lists of genes from five different clinical laboratories that offer them in Brazil. A total of 425 occurrences of 351 rare variants were reported in 278 different genes from 230 patients (71.9%). Almost half (48.8%) were carriers of at least one heterozygous pathogenic/likely pathogenic variant for rare metabolic disorders, while 25.9% of epilepsy, 18.1% of intellectual disabilities, 15.6% of skeletal disorders, 10.9% immune disorders, and 9.1% of hearing loss. We estimated that an average of 67% of the variants would not have been detected by carrier screening panels. The combined frequencies of autosomal recessive diseases were estimated to be 26.39/10,000 (or ~0.26%). This study shows the potential research utility of WES to determine carrier status, which may be a possible strategy to evaluate the clinical and social burden of recessive diseases at the population level and guide the optimization of carrier screening panels.

Effect of tocilizumab on clinical outcomes at 15 days in patients with severe or critical coronavirus disease 2019: randomised controlled trial.

OBJECTIVE: To determine whether tocilizumab improves clinical outcomes for patients with severe or critical coronavirus disease 2019 (covid-19). DESIGN: Randomised, open label trial. SETTING: Nine hospitals in Brazil, 8 May to 17 July 2020. PARTICIPANTS: Adults with confirmed covid-19 who were receiving supplemental oxygen or mechanical ventilation and had abnormal levels of at least two serum biomarkers (C reactive protein, D dimer, lactate dehydrogenase, or ferritin). The data monitoring committee recommended stopping the trial early, after 129 patients had been enrolled, because of an increased number of deaths at 15 days in the tocilizumab group. INTERVENTIONS: Tocilizumab (single intravenous infusion of 8 mg/kg) plus standard care (n=65) versus standard care alone (n=64). MAIN OUTCOME MEASURE: The primary outcome, clinical status measured at 15 days using a seven level ordinal scale, was analysed as a composite of death or mechanical ventilation because the assumption of odds proportionality was not met. RESULTS: A total of 129 patients were enrolled (mean age 57 (SD 14) years; 68% men) and all completed follow-up. All patients in the tocilizumab group and two in the standard care group received tocilizumab. 18 of 65 (28%) patients in the tocilizumab group and 13 of 64 (20%) in the standard care group were receiving mechanical ventilation or died at day 15 (odds ratio 1.54, 95% confidence interval 0.66 to 3.66; P=0.32). Death at 15 days occurred in 11 (17%) patients in the tocilizumab group compared with 2 (3%) in the standard care group (odds ratio 6.42, 95% confidence interval 1.59 to 43.2). Adverse events were reported in 29 of 67 (43%) patients who received tocilizumab and 21 of 62 (34%) who did not receive tocilizumab. CONCLUSIONS: In patients with severe or critical covid-19, tocilizumab plus standard care was not superior to standard care alone in improving clinical outcomes at 15 days, and it might increase mortality. TRIAL REGISTRATION: ClinicalTrials.gov NCT04403685.

Assessment of initial SARS-CoV-2 seroprevalence in the most affected districts in the municipality of São Paulo, Brazil

ABSTRACT Background: São Paulo city has been one of the regions most affected by the COVID-19 pandemic in Brazil. Frequent asymptomatic and oligosymptomatic infections and poor access to diagnostic tests make serosurveys crucial to monitor the magnitude of the epidemic and to inform public health policies, such as vaccination plans. Objectives: To estimate, early in the epidemic, the seroprevalence of antibodies to SARS-CoV-2 in adults living in the six most affected districts in São Paulo city, and to assess potential associated risk factors. Methods: This was a cross-sectional population-based survey of 1,152 households randomly selected from 72 census tracts. During the period May 4-12, 2020, 463 participants completed a questionnaire on sociodemographic characteristics and history of symptoms in the past two weeks, and provided a blood sample. Prevalence of SARS-CoV-2 antibodies was the outcome of interest and was estimated based on results of two immunoassays, Maglumi SARS-CoV-2 chemiluminescence assay Immunoglobulin (Ig) M (IgM) and IgG, and Roche electrochemiluminescence assay total Ig. Serum samples reactive to either assay were considered positive. Results: Weighted overall seroprevalence was 6% (95%CI 3.9-8.3%). No association was observed between seropositivity and sex, age group or education level. Participants who reported black and brown skin color showed a 2.7 fold higher prevalence than people with white skin (p = 0.007). Among the 30 seropositive individuals, 14 (46.6%) reported no COVID-19 compatible symptoms in the past two weeks. Conclusion: This study represents the first assessment of SARS-CoV-2 seroprevalence in the city of São Paulo and 6% is the baseline estimate of a series of population-based seroprevalence surveys. Serological screening using sound serological assays is the key tool to monitoring temporal and geographic changes in the spread of the virus through an important epicenter of the COVID-19 pandemic in Brazil. Ultimately, it may inform prevention and control efforts.

Establishing a mass spectrometry-based system for rapid detection of SARS-CoV-2 in large clinical sample cohorts.

The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is pressing public health systems around the world, and large population testing is a key step to control this pandemic disease. Here, we develop a high-throughput targeted proteomics assay to detect SARS-CoV-2 nucleoprotein peptides directly from nasopharyngeal and oropharyngeal swabs. A modified magnetic particle-based proteomics approach implemented on a robotic liquid handler enables fully automated preparation of 96 samples within 4 hours. A TFC-MS system allows multiplexed analysis of 4 samples within 10 min, enabling the processing of more than 500 samples per day. We validate this method qualitatively (Tier 3) and quantitatively (Tier 1) using 985 specimens previously analyzed by real-time RT-PCR, and detect up to 84% of the positive cases with up to 97% specificity. The presented strategy has high sample stability and should be considered as an option for SARS-CoV-2 testing in large populations.

Diagnostic power and clinical impact of exome sequencing in a cohort of 500 patients with rare diseases.

Rare diseases comprise a diverse group of conditions, most of which involve genetic causes. We describe the variable spectrum of findings and clinical impacts of exome sequencing (ES) in a cohort of 500 patients with rare diseases. In total, 164 primary findings were reported in 158 patients, representing an overall diagnostic yield of 31.6%. Most of the findings (61.6%) corresponded to autosomal dominant conditions, followed by autosomal recessive (25.6%) and X-linked (12.8%) conditions. These patients harbored 195 variants, among which 43.6% are novel in the literature. The rate of molecular diagnosis was considerably higher for prenatal samples (67%; 4/6), younger children (44%; 24/55), consanguinity (50%; 3/6), gastrointestinal/liver disease (44%; 16/36) and syndromic/malformative conditions (41%; 72/175). For 15.6% of the cohort patients, we observed a direct potential for the redirection of care with targeted therapy, tumor screening, medication adjustment and monitoring for disease-specific complications. Secondary findings were reported in 37 patients (7.4%). Based on cost-effectiveness studies in the literature, we speculate that the reports of secondary findings may influence an increase of 123.2 years in the life expectancy for our cohort, or 0.246 years/cohort patient. ES is a powerful method to identify the molecular bases of monogenic disorders and redirect clinical care.

Rationale and design of the "Tocilizumab in patients with moderate to severe COVID-19: an open-label multicentre randomized controlled" trial (TOCIBRAS). / Justificativa e delineamento do estudo "Tocilizumabe em pacientes com COVID-19 moderado a grave: estudo aberto, multicêntrico, randomizado, controlado" (TOCIBRAS).

INTRODUCTION: Pro-inflammatory markers play a significant role in the disease severity of patients with COVID-19. Thus, anti-inflammatory therapies are attractive agents for potentially combating the uncontrolled inflammatory cascade in these patients. We designed a trial testing tocilizumab versus standard of care intending to improve the outcomes by inhibiting interleukin-6, an important inflammatory mediator in COVID-19. METHODS AND ANALYSIS: This open-label multicentre randomized controlled trial will compare clinical outcomes of tocilizumab plus standard of care versus standard of care alone in patients with moderate to severe COVID-19. Two of the following four criteria are required for protocol enrolment: D-dimer > 1,000ng/mL; C reactive protein > 5mg/dL, ferritin > 300mg/dL, and lactate dehydrogenase > upper limit of normal. The primary objective will be to compare the clinical status on day 15, as measured by a 7-point ordinal scale applied in COVID-19 trials worldwide. The primary endpoint will be assessed by an ordinal logistic regression assuming proportional odds ratios adjusted for stratification variables (age and sex). ETHICS AND DISSEMINATION: The TOCIBRAS protocol was approved by local and central (national) ethical committees in Brazil following current national and international guidelines/directives. Each participating center had the study protocol approved by their institutional review boards before initiating protocol enrolment. The data derived from this trial will be published regardless of the results. If proven active, this strategy could alleviate the consequences of the inflammatory response in COVID-19 patients and improve their clinical outcomes.

INTRODUÇÃO: Os marcadores pró-inflamatórios desempenham papel importante na severidade de pacientes com COVID-19. Assim, terapêuticas anti-inflamatórias são agentes interessantes para potencialmente combater a cascata inflamatória descontrolada em tais pacientes. Delineamos um ensaio para testar tocilizumabe em comparação com o tratamento padrão, tendo como objetivo melhorar os desfechos por meio da inibição da interleucina 6, um importante mediador inflamatório na COVID-19. MÉTODOS E ANÁLISES: Este será um estudo aberto multicêntrico, randomizado e controlado, que comparará os desfechos de pacientes tratados com tocilizumabe mais tratamento padrão com o tratamento padrão isoladamente em pacientes com COVID-19 moderada a grave. Como critérios de inclusão, serão exigidos dois dos quatro critérios a seguir: dosagens de dímero D acima de 1.000ng/mL, proteína C-reativa acima de 5mg/dL, ferritina acima de 300mg/dL e desidrogenase lática acima do limite superior do normal. O objetivo primário será comparar a condição clínica no dia 15, conforme avaliação por meio de escala ordinal de 7 pontos aplicada nos estudos de COVID-19 em todo o mundo. O desfecho primário será avaliado por regressão logística ordinal assumindo razões de propensão proporcionais ajustadas pelas variáveis de estratificação (idade e sexo). ÉTICA E DISSEMINAÇÃO: O TOCIBRAS foi aprovado pelos comitês de ética locais e central (nacional) do Brasil em conformidade com as atuais diretrizes e orientações nacionais e internacionais. Cada centro participante obteve aprovação do estudo por parte de seu comitê de ética em pesquisa, antes de iniciar as inscrições no protocolo. Os dados derivados deste ensaio serão publicados independentemente de seus resultados. Se tiver sua efetividade comprovada, esta estratégia terapêutica poderá aliviar as consequências da resposta inflamatória na COVID-19 e melhorar os resultados clínicos.

Justificativa e delineamento do estudo Tocilizumabe em pacientes com COVID-19 moderado a grave: estudo aberto, multicêntrico, randomizado, controlado (TOCIBRAS) / Rationale and design of the Tocilizumab in patients with moderate to severe COVID-19: an open-label multicentre randomized controlled trial (TOCIBRAS)

RESUMO Introdução: Os marcadores pró-inflamatórios desempenham papel importante na severidade de pacientes com COVID-19. Assim, terapêuticas anti-inflamatórias são agentes interessantes para potencialmente combater a cascata inflamatória descontrolada em tais pacientes. Delineamos um ensaio para testar tocilizumabe em comparação com o tratamento padrão, tendo como objetivo melhorar os desfechos por meio da inibição da interleucina 6, um importante mediador inflamatório na COVID-19. Métodos e análises: Este será um estudo aberto multicêntrico, randomizado e controlado, que comparará os desfechos de pacientes tratados com tocilizumabe mais tratamento padrão com o tratamento padrão isoladamente em pacientes com COVID-19 moderada a grave. Como critérios de inclusão, serão exigidos dois dos quatro critérios a seguir: dosagens de dímero D acima de 1.000ng/mL, proteína C-reativa acima de 5mg/dL, ferritina acima de 300mg/dL e desidrogenase lática acima do limite superior do normal. O objetivo primário será comparar a condição clínica no dia 15, conforme avaliação por meio de escala ordinal de 7 pontos aplicada nos estudos de COVID-19 em todo o mundo. O desfecho primário será avaliado por regressão logística ordinal assumindo razões de propensão proporcionais ajustadas pelas variáveis de estratificação (idade e sexo). Ética e disseminação: O TOCIBRAS foi aprovado pelos comitês de ética locais e central (nacional) do Brasil em conformidade com as atuais diretrizes e orientações nacionais e internacionais. Cada centro participante obteve aprovação do estudo por parte de seu comitê de ética em pesquisa, antes de iniciar as inscrições no protocolo. Os dados derivados deste ensaio serão publicados independentemente de seus resultados. Se tiver sua efetividade comprovada, esta estratégia terapêutica poderá aliviar as consequências da resposta inflamatória na COVID-19 e melhorar os resultados clínicos.

ABSTRACT Introduction: Pro-inflammatory markers play a significant role in the disease severity of patients with COVID-19. Thus, anti-inflammatory therapies are attractive agents for potentially combating the uncontrolled inflammatory cascade in these patients. We designed a trial testing tocilizumab versus standard of care intending to improve the outcomes by inhibiting interleukin-6, an important inflammatory mediator in COVID-19. Methods and analysis: This open-label multicentre randomized controlled trial will compare clinical outcomes of tocilizumab plus standard of care versus standard of care alone in patients with moderate to severe COVID-19. Two of the following four criteria are required for protocol enrolment: D-dimer > 1,000ng/mL; C reactive protein > 5mg/dL, ferritin > 300mg/dL, and lactate dehydrogenase > upper limit of normal. The primary objective will be to compare the clinical status on day 15, as measured by a 7-point ordinal scale applied in COVID-19 trials worldwide. The primary endpoint will be assessed by an ordinal logistic regression assuming proportional odds ratios adjusted for stratification variables (age and sex). Ethics and dissemination: The TOCIBRAS protocol was approved by local and central (national) ethical committees in Brazil following current national and international guidelines/directives. Each participating center had the study protocol approved by their institutional review boards before initiating protocol enrolment. The data derived from this trial will be published regardless of the results. If proven active, this strategy could alleviate the consequences of the inflammatory response in COVID-19 patients and improve their clinical outcomes.

Effect of the levonorgestrel-releasing intrauterine system on cardiovascular risk markers among women with thrombophilia or previous venous thromboembolism.

OBJECTIVE: To assess the effects of the levonorgestrel-releasing intrauterine system (LNG-IUS) on standard cardiovascular risk markers among women with thrombophilia and/or previous venous thromboembolism (VTE). METHODS: A prospective cohort study enrolled women aged 18-45 years with thrombophilia and/or a history of VTE who received the 52-mg LNG-IUS (20 µg/d initial release) at the University of Ribeirão Preto Medical School, Brazil, from January 2006 to December 2015. Before and 12 months after LNG-IUS placement, the following cardiovascular risk markers were assessed: lipid profile, body mass index (BMI), blood glucose, systolic blood pressure, diastolic blood pressure, and waist circumference. The primary outcome was changes in cardiovascular risk markers. A subanalysis of anticoagulant users versus non-users was also conducted. RESULTS: In total, 45 women were enrolled. BMI increased by 2.3% after 12 months of LNG-IUS placement (P < 0.01), but the other risk factors did not change. Cardiovascular risk markers were similar between anticoagulant users and non-users after 12 months of LNG-IUS use. CONCLUSION: Among women with thrombophilia and/or previous VTE, cardiovascular risk markers were not found to change significantly after 12 months of LNG-IUS use. The study adds safety information regarding use of the LNG-IUS for women at risk of thromboembolism.

Error in body weight estimation leads to inadequate parenteral anticoagulation.

Parenteral anticoagulation is a cornerstone in the management of venous and arterial thrombosis. Unfractionated heparin has a wide dose/response relationship, requiring frequent and troublesome laboratorial follow-up. Because of all these factors, low-molecular-weight heparin use has been increasing. Inadequate dosage has been pointed out as a potential problem because the use of subjectively estimated weight instead of real measured weight is common practice in the emergency department (ED). To evaluate the impact of inadequate weight estimation on enoxaparin dosage, we investigated the adequacy of anticoagulation of patients in a tertiary ED where subjective weight estimation is common practice. We obtained the estimated, informed, and measured weight of 28 patients in need of parenteral anticoagulation. Basal and steady-state (after the second subcutaneous shot of enoxaparin) anti-Xa activity was obtained as a measure of adequate anticoagulation. The patients were divided into 2 groups according the anticoagulation adequacy. From the 28 patients enrolled, 75% (group 1, n = 21) received at least 0.9 mg/kg per dose BID and 25% (group 2, n = 7) received less than 0.9 mg/kg per dose BID of enoxaparin. Only 4 (14.3%) of all patients had anti-Xa activity less than the inferior limit of the therapeutic range (<0.5 UI/mL), all of them from group 2. In conclusion, when weight estimation was used to determine the enoxaparin dosage, 25% of the patients were inadequately anticoagulated (anti-Xa activity <0.5 UI/mL) during the initial crucial phase of treatment.

Incidence and risk factors of aplastic anemia in Latin American countries: the LATIN case-control study.

UNLABELLED: Background Associations between aplastic anemia and numerous drugs, pesticides and chemicals have been reported. However, at least 50% of the etiology of aplastic anemia remains unexplained. DESIGN AND METHODS: This was a case-control, multicenter, multinational study, designed to identify risk factors for agranulocytosis and aplastic anemia. The cases were patients with diagnosis of aplastic anemia confirmed through biopsy or bone marrow aspiration, selected through an active search of clinical laboratories, hematology clinics and medical records. The controls did not have either aplastic anemia or chronic diseases. A total of 224 patients with aplastic anemia were included in the study, each case was paired with four controls, according to sex, age group, and hospital where the case was first seen. Information was collected on demographic data, medical history, laboratory tests, medications, and other potential risk factors prior to diagnosis. RESULTS: The incidence of aplastic anemia was 1.6 cases per million per year. Higher rates of benzene exposure (>/=30 exposures per year) were associated with a greater risk of aplastic anemia (odds ratio, OR: 4.2; 95% confidence interval, CI: 1.82-9.82). Individuals exposed to chloramphenicol in the previous year had an adjusted OR for aplastic anemia of 8.7 (CI: 0.87-87.93) and those exposed to azithromycin had an adjusted OR of 11.02 (CI 1.14-108.02). Conclusions The incidence of aplastic anemia in Latin America countries is low. Although the research study centers had a high coverage of health services, the underreporting of cases of aplastic anemia in selected regions can be discussed. Frequent exposure to benzene-based products increases the risk for aplastic anemia. Few associations with specific drugs were found, and it is likely that some of these were due to chance alone.

Incidence and risk factors for agranulocytosis in Latin American countries--the Latin Study: a multicenter study.

PURPOSE: LATIN is a multinational case-control study designed to identify risk factors for agranulocytosis and to estimate the incidence rate of the disease in some Latin American countries. METHODS: Each study site in Brazil, Argentina and Mexico conducted an active search of agranulocytosis patients in hematology clinics and looked for possible associations with drug use. RESULTS: The overall incidence rate was 0.38 cases per 1 million inhabitant-years. Agranulocytosis patients more often took medications already associated with agranulocytosis than controls (p = 0.01), mainly methimazole (OR 44.2, 95% CI 6.8 to infinity). The population attributable risk percentage (etiologic fraction) was 56%. The use of nutrient supplements was more frequent among patients than controls (p = 0.03). CONCLUSIONS: Agranulocytosis seems to be very rare in Latin America. The lower than expected number of cases identified during the study period precluded estimation of the risk associated to individual drugs, with the exception of methimazol. However, this is the longest series of agranulocytosis cases ever gathered in Latin America, and information on drug exposures was collected prospectively. The conclusion is that drug-induced agranulocytosis does not seem to be a major public health problem in the study regions.

Determination of P-glycoprotein, MDR-related protein 1, breast cancer resistance protein, and lung-resistance protein expression in leukemic stem cells of acute myeloid leukemia.

BACKGROUND: The most primitive leukemic precursor in acute myeloid leukemia (AML) is thought to be the leukemic stem cell (LSC), which retains the properties of self-renewal and high proliferative capacity and quiescence of the hematopoietic stem cell. LSC seems to be immunophenotypically distinct and more resistant to chemotherapy than the more committed blasts. Considering that the multidrug resistance (MDR) constitutive expression may be a barrier to therapy in AML, we have investigated whether various MDR transporters were differentially expressed at the protein level by different leukemic subsets. METHODS: The relative expression of the drug-efflux pumps P-gp, MRP, LRP, and BCRP was evaluated by mean fluorescence index (MFI) and the Kolmogorov-Smirnov analysis (D values) in five leukemic subpopulations: CD34+CD38-CD123+ (LSCs), CD34+CD38+CD123-, CD34+CD38+CD123+, CD34+CD38+CD123-, and CD34- mature cells in 26 bone marrow samples of CD34+ AML cases. RESULTS: : The comparison between the two more immature subsets (LSC versus CD34+CD38-CD123- cells) revealed a higher P-gp, MRP, and LRP expression in LSCs. The comparative analysis between LSCs and subsets of intermediate maturation (CD34+CD38+) demonstrated the higher BCRP expression in the LSCs. In addition, P-gp expression was also significantly higher in the LSC compared to CD34+CD38+CD123- subpopulation. Finally, the comparative analysis between LSC and the most mature subset (CD34-) revealed higher MRP and LRP and lower P-gp expression in the LSCs. CONCLUSIONS: Considering the cellular heterogeneity of AML, the higher MDR transporters expression at the most immature, self-renewable, and quiescent LSC population reinforces that MDR is one of the mechanisms responsible for treatment failure.

Lack of mutations in the human telomerase RNA component (hTERC) gene in Fanconi's anemia.

As some patients with Fanconi s anemia (FA) present excessive telomere shortening correlating with poor outcome, we investigated whether human telomerase RNA component (hTERC) mutations also play a role in telomere shortening in 115 FA patients. Only one patient was heterozygous for the G58A polymorphism. No other mutation or deletion was found. We conclude that hTERC gene mutations do not contribute to telomere shortening in FA.

Tratamento de distúrbios hemostáticos em urgência médica / Management of hemostatic disorders in the emergency room

Patologias do sistema hemostático são causas freqüentes de atendimento médico de urgência. Este texto revisa aspectos relevantes no que diz respeito a diagnóstico e tratamento de hemofilias e coagulação intravascular disseminada (CIVD)