Detection of multidrug-resistant Mycobacterium tuberculosis strains isolated in Brazil using a multimarker genetic assay for katG and rpoB genes

Abstract Multidrug-resistant tuberculosis (MDRTB) is a serious world health problem that limits public actions to control tuberculosis, because the most used anti-tuberculosis first-line drugs fail to stop mycobacterium spread. Consequently, a quick detection through molecular diagnosis is essential to reduce morbidity and medical costs. Despite the availability of several molecular-based commercial-kits to diagnose multidrug-resistant tuberculosis, their diagnostic value might diverge worldwide since Mycobacterium tuberculosis genetic variability differs according to geographic location. Here, we studied the predictive value of four common mycobacterial mutations in strains isolated from endemic areas of Brazil. Mutations were found at the frequency of 41.9% for katG, 25.6% for inhA, and 69.8% for rpoB genes in multidrug-resistant strains. Multimarker analysis revealed that combination of only two mutations (“katG/S315T + rpoB/S531L”) was a better surrogate of multidrug-resistant tuberculosis than single-marker analysis (86% sensitivity vs. 62.8%). Prediction of multidrug-resistant tuberculosis was not improved by adding a third or fourth mutation in the model. Therefore, rather than using diagnostic kits detecting several mutations, we propose a simple dual-marker panel to detect multidrug-resistant tuberculosis, with 86% sensitivity and 100% specificity. In conclusion, this approach (previous genetic study + analysis of only prevalent markers) would considerably decrease the processing costs while retaining diagnostic accuracy.

Interleukin-10 rs2227307 and CXCR2 rs1126579 polymorphisms modulate the predisposition to septic shock

Despite major improvements in its treatment and diagnosis, sepsis is still a leading cause of death and admittance to the intensive care unit (ICU). Failure to identify patients at high risk of developing septic shock contributes to an increase in the sepsis burden and rapid molecular tests are currently the most promising avenue to aid in patient risk determination and therapeutic anticipation. The primary goal of this study was to evaluate the genetic susceptibility that affects sepsis outcome in 72 sepsis patients admitted to the ICU. Seven polymorphisms were genotyped in key inflammatory response genes in sepsis, including tumour necrosis factor-α, interlelukin (IL)-1β, IL-10, IL-8, Toll-like receptor 4, CXCR1 and CXCR2. The primary finding showed that patients who were homozygous for the major A allele in IL-10 rs1800896 had almost five times higher chance to develop septic shock compared to heterozygotes. Similarly, selected clinical features and CXCR2 rs1126579 single nucleotide polymorphisms modulated septic shock susceptibility without affecting survival. These data support the hypothesis that molecular testing has clinical usefulness to improve sepsis prognostic models. Therefore, enrichment of the ICU portfolio by including these biomarkers will aid in the early identification of sepsis patients who may develop septic shock.

Molecular medicine: a path towards a personalized medicine / Medicina molecular: um passo em direção à medicina personalizada

Psychiatric disorders are among the most common human illnesses; still, the molecular and cellular mechanisms underlying their complex pathophysiology remain to be fully elucidated. Over the past 10 years, our group has been investigating the molecular abnormalities in major signaling pathways involved in psychiatric disorders. Recent evidences obtained by the Instituto Nacional de Ciência e Tecnologia de Medicina Molecular (National Institute of Science and Technology - Molecular Medicine, INCT-MM) and others using behavioral analysis of animal models provided valuable insights into the underlying molecular alterations responsible for many complex neuropsychiatric disorders, suggesting that "defects" in critical intracellular signaling pathways have an important role in regulating neurodevelopment, as well as in pathophysiology and treatment efficacy. Resources from the INCT have allowed us to start doing research in the field of molecular imaging. Molecular imaging is a research discipline that visualizes, characterizes, and quantifies the biologic processes taking place at cellular and molecular levels in humans and other living systems through the results of image within the reality of the physiological environment. In order to recognize targets, molecular imaging applies specific instruments (e.g., PET) that enable visualization and quantification in space and in real-time of signals from molecular imaging agents. The objective of molecular medicine is to individualize treatment and improve patient care. Thus, molecular imaging is an additional tool to achieve our ultimate goal.

Os transtornos psiquiátricos estão entre as doenças humanas mais comuns. Os mecanismos celulares e moleculares subjacentes à sua complexa fisiopatologia ainda não estão totalmente esclarecidos. Nosso grupo está envolvido na investigação de anormalidades moleculares nas principais vias de sinalização das doenças psiquiátricas nos últimos 10 anos. Evidências recentemente obtidas pelo Instituto Nacional de Ciência e Tecnologia de Medicina Molecular (INCT-MM), utilizando análise comportamental de modelos animais, forneceram informações valiosas sobre as alterações moleculares subjacentes responsáveis por muitos distúrbios neuropsiquiátricos complexos, sugerindo que os "defeitos" nas vias de sinalização intracelular têm um papel importante na regulação do neurodesenvolvimento, bem como na fisiopatologia e eficácia do tratamento. Recursos do INCT nos permitiram iniciar pesquisas na área de imagem molecular. A imagem molecular é uma disciplina de investigação que visualiza, caracteriza e quantifica processos biológicos que ocorrem em níveis celular e molecular em seres humanos, e em outros sistemas vivos, através dos resultados de imagem dentro da realidade do ambiente fisiológico. A fim de reconhecer alvos, a imagem molecular aplica instrumentos específicos (PET, por exemplo) que permitem a visualização e quantificação em espaço e tempo real dos sinais dos agentes de imagem molecular, fornecendo medições de processos a nível molecular e celular. O objetivo da medicina molecular é individualizar o tratamento e melhorar a assistência ao paciente. Desse modo, a imagem molecular consiste em mais uma ferramenta para atingirmos nosso objetivo final.

Factors influencing possible delay in the diagnosis of Alzheimer's disease: Findings from a tertiary Public University Hospital / Fatores que influenciam o possível atraso no diagnóstico da doença de Alzheimer: achados de um Hospital Universitário Público

Alzheimer's disease (AD) is characterized by impairment in memory and autonomy, causing excessive pressure on family and an overburdened health care system. Early diagnosis, with the appropriate treatment, is important to reduce the pattern of disease progression. Objective: The study sought to identify the most probable causes of delay in diagnosis. Methods: A cross-sectional study involving AD patients followed at an Outpatient Geriatric Clinic from a tertiary public university hospital was conducted between June 2009 and February 2011. Results: Ninety-four patients were evaluated (66% women), aged 77.76±6.8 years and with median educational level of 3 years (95% CI 2.7-3.80). Regarding severity of dementia, 51.8% of patients were classified as having mild dementia (CDR 1), 40% moderate dementia (CDR 2) and 8.2% severe dementia (CDR 3). Mean educational level of caregivers was 8.3±3.9 years. Among those who believed there was a delay, 36% stated that the "family thought that the changes were normal for the age of the patient" reporting average delay of 1.8 years (95% CI: 1.3-2.5) while 45.3% stated that the "doctor did not reach a diagnosis" reporting a median delay of 1.5 years (95% CI: 1.4-2.3). Conclusion: Based on these results, it can be concluded the time between onset of symptoms and diagnosis was excessive. This study may be useful to help increase awareness of issues not sufficiently discussed in the literature, such as diagnostic delay and influence of caregivers' educational level on treatment.

A doença de Alzheimer é caracterizada por comprometimento na memória e na autonomia, causando pressão excessiva em familiares e sobrecarregando o sistema público de saúde. O diagnóstico precoce, com o tratamento adequado, é importante para reduzir o padrão de evolução da doença. Objetivo: O estudo pretende identificar as causas mais prováveis de atraso no diagnóstico. Métodos: Trata-se de um estudo transversal envolvendo pacientes com DA acompanhados em Ambulatório de Geriatria de um hospital terciário público entre junho de 2009 e fevereiro de 2011. Resultados: Noventa e quatro pacientes foram avaliados (66% mulheres), com média de idade de 77,8±6,8 anos e com mediana de escolaridade de 3 anos (IC 95%: 2,7-3,8). Quanto à gravidade da doença, 51,8% foram classificados como demência leve (CDR 1), 40% como demência moderada (CDR 2) e 8,2% como demência grave (CDR 3). A escolaridade do cuidador foi de 8,3±3,9 anos. Entre aqueles que acreditavam que havia um atraso no diagnóstico, 36% responderam que "a família achava as alterações como normais para a idade do paciente", com média de 1,8 anos (IC 95%: 1,3-2,5) e 45,3% responderam que "o médico não fez o diagnóstico", com mediana de 1,5 anos (IC 95%: 1,4-2,3). Foi observado que o tempo entre o início dos sintomas e o diagnóstico foi maior do que deveria ser. Conclusão: Este estudo pode contribuir para aumentar o conhecimento sobre questões ainda pouco discutidas na literatura científica, como atraso no diagnóstico e influência da escolaridade do cuidador no tratamento.