Characterizing a transition from limited to unlimited diffusion in energy for a time-dependent stochastic billiard.

We explore Fermi acceleration in a stochastic oval billiard which shows unlimited to limited diffusion in energy when passing from the free to the dissipative case. We provide evidence for a transition from limited to unlimited energy growth taking place while detuning the corresponding restitution coefficient responsible for the degree of dissipation. A corresponding order parameter is suggested, and its susceptibility is shown to diverge at the critical point. We show that this order parameter is also be applicable to the periodically driven oval billiard and discuss the elementary excitation of the controlled diffusion process.

Dynamical aspects of a bouncing ball in a nonhomogeneous field.

We study some dynamical properties of a charged particle that moves in a nonhomogeneous electric field and collides against an oscillating platform. Depending on the values of parameters, the system presents (i) predominantly regular dynamics or (ii) structures of chaotic behavior in phase space conditioned to the initial conditions. The localization of the fixed points and their stability are carefully discussed. Average properties of the chaotic sea are investigated under a scaling approach. We show that the system belongs to the same universality class as the Fermi-Ulam model.

Prática de exercícios em indivíduo com transposição de grandes artérias submetido à cirurgia de Jatene / Exercise practice in an individual with transposition of large arteries who underwent Jatene surgery

INTRODUÇÃO: Historicamente, a cardiopatia congênita traz redução da qualidade de vida da criança portadora da patologia. Com o aprimoramento das formas de correção, estes pacientes apresentam melhor sobrevida, de forma que hoje há mais adultos com cardiopatia congênita. A prática de atividade física vem sendo encorajada nesses pacientes. Relatamos um caso de um paciente portador de cardiopatia congênita cianótica corrigida nos primeiros dias de vida, atualmente praticante de atividade física. Relato de caso: Paciente masculino, 26 anos, com dextro transposição de grandes artérias (DTGA), comunicação interatrial e persistência do canal arterial. Aos 09 dias de vida, submetido a procedimento para correção da cardiopatia, por meio da cirurgia de Jatene (CJ) com manobra de Lecompte. Aos 18 anos manifestou desejo de praticar atividade física, sendo feita avaliação pré-participação. Cintilografia do Miocárdio com ausência de sinais de isquemia; Teste ergométrico (TE) com boa capacidade funcional, Extras sístoles ventriculares isoladas e raras; ecocardiograma transtorácico dentro da normalidade. Atualmente realiza atividade física resistida (musculação 80 min por dia, 6 dias por semana), sem sintomas durante a prática ou o repouso. Em exames atuais observa--se: TE em ritmo atrial multifocal, sem alterações sugestivas de isquemia, com boa capacidade aeróbica (16,2 METs e VO2 56 mL/kg. min); Ressonância miocárdica com câmaras cardíacas de dimensões preservadas, função sistólica biventricular preservada, ausência de áreas de edema, gordura ou fibrose. DISCUSSÃO e CONCLUSÃO: A DTGA corresponde a cerca de 8% de todas as cardiopatias congênitas, com alto índice de letalidade antes do surgimento de correções cirúrgicas, chegando a 90% de mortalidade no primeiro ano de vida. Inicialmente reduzia-se danos da DTGA através de correção atrial. Com o desenvolvimento da CJ (ou switch arterial) houve melhora progressiva do prognóstico e qualidade de vida, principalmente se realizada nos primeiros dias de vida. Devido a isso, muitos pacientes submetidos à CJ praticam exercícios físicos ou atividades competitivas, tornando o acompanhamento um desafio para o cardiologista, visto que não há evidências robustas sobre os impactos de tais atividades a longo prazo. Conclui-se a importância de seguimento com exames periódicos de tais pacientes, com coleta de dados e a necessidade de mais estudos para este cenário.

Where do we aspire to publish? A position paper on scientific communication in biochemistry and molecular biology.

The scientific publication landscape is changing quickly, with an enormous increase in options and models. Articles can be published in a complex variety of journals that differ in their presentation format (online-only or in-print), editorial organizations that maintain them (commercial and/or society-based), editorial handling (academic or professional editors), editorial board composition (academic or professional), payment options to cover editorial costs (open access or pay-to-read), indexation, visibility, branding, and other aspects. Additionally, online submissions of non-revised versions of manuscripts prior to seeking publication in a peer-reviewed journal (a practice known as pre-printing) are a growing trend in biological sciences. In this changing landscape, researchers in biochemistry and molecular biology must re-think their priorities in terms of scientific output dissemination. The evaluation processes and institutional funding for scientific publications should also be revised accordingly. This article presents the results of discussions within the Department of Biochemistry, University of São Paulo, on this subject.

Oral Transmission of Trypanosoma cruzi, Brazilian Amazon.

In the Brazilian Amazon, the suspected source of infection in an outbreak of acute Chagas disease involving 10 patients was Euterpe oleracea (açaí berry) juice. Patient blood and juice samples contained Trypanosoma cruzi TcIV, indicating oral transmission of the Chagas disease agent.

Where do we aspire to publish? A position paper on scientific communication in biochemistry and molecular biology

The scientific publication landscape is changing quickly, with an enormous increase in options and models. Articles can be published in a complex variety of journals that differ in their presentation format (online-only or in-print), editorial organizations that maintain them (commercial and/or society-based), editorial handling (academic or professional editors), editorial board composition (academic or professional), payment options to cover editorial costs (open access or pay-to-read), indexation, visibility, branding, and other aspects. Additionally, online submissions of non-revised versions of manuscripts prior to seeking publication in a peer-reviewed journal (a practice known as pre-printing) are a growing trend in biological sciences. In this changing landscape, researchers in biochemistry and molecular biology must re-think their priorities in terms of scientific output dissemination. The evaluation processes and institutional funding for scientific publications should also be revised accordingly. This article presents the results of discussions within the Department of Biochemistry, University of São Paulo, on this subject.

Adult Food Allergy Prevalence: Reducing Questionnaire Bias.

BACKGROUND: Food allergy (FA) prevalence has increased in the last decades, but epidemiologic studies could show overestimated results. The objective of this study is to estimate the prevalence of immediate FA in adults in a region of Central Brazil, using a questionnaire to try to reduce misperceptions about FA reaction. METHODS: A cross-sectional study was conducted, enrolling an adult population aged 18-65 years comprised of families in a Central Brazilian city. In the first phase, participants answered a self-administered questionnaire for FA screening. In the second phase, the participants who reported an FA in the first questionnaire were visited to complete the second questionnaire applied by trained researchers. RESULTS: Of the 4,916 adults visited, 1,583 returned a completed questionnaire. Reported FA occurred in 171 (10.8%) subjects, and the more frequent citations were cow's milk, pork, fruits, shrimp, and vegetables. One hundred and four of these individuals completed the second questionnaire, and 15 (1.0%) were considered to have an FA diagnosis. The main foods were fruits, followed by cow's milk, shrimp, pork, and vegetables. CONCLUSION: After use of a specific questionnaire to recognize possible IgE-mediated FAs, a low frequency of FA was considered in this population. Use of a directed questionnaire administered by trained researchers could be an alternative for epidemiological IgE-mediated FA studies to achieve more accurate results.

Squamous odontogenic tumor: report of a case of unusual involvement / Tumor odontogênico escamoso: relato de um caso de envolvimento incomum

ABSTRACT The squamous odontogenic tumor (SOT) is defined as a very rare benign neoplasm, locally infiltrative and can extend to neighboring structures. This study aimed to report a case of SOT unusual involvement. A female patient, 56-year-old, smoker showed mild swelling in the chin region in the portion between the left canine and right first premolar. Axial, coronal and sagittal images showed expansive hypodense lesion in the mandibular symphysis and parasymphysis. Partial removal of the lesion was performed, which led to the diagnosis of SOT. The patient presented no recurrence during 4 years and 2 months follow-up.

RESUMO O tumor odontogênico escamoso (TOE) é definido como uma neoplasia benigna rara, localmente infiltrativa, podendo estender-se a estruturas vizinhas. Objetivou-se relatar um caso de TOE de acometimento incomum. Paciente do sexo feminino, 56 anos de idade, fumante, demonstrou leve aumento de volume na região do mento na porção compreendida entre o canino esquerdo e o primeiro pré-molar direito. Imagens axial, coronal e sagital demonstraram lesão expansiva hipodensa na sínfise e na linha média mandibular. Fez-se a remoção parcial da lesão, o que levou ao diagnóstico de TOE. A paciente não apresentou recidiva durante quatro anos e dois meses de acompanhamento.

Performance of absolute CD4+ count in predicting co-infection with human T-lymphotropic virus type 1 in antiretroviral-naive HIV-infected patients.

Early identification of patients co-infected with HIV and human T-lymphotropic virus type 1 (HTLV-1) is essential to improve care, as CD4+ T-cell counts have been revealed to be an unreliable laboratory parameter to monitor HIV infection in co-infection. Unfortunately, HTLV-1 testing is not currently available in sub-Saharan Africa. We conducted this study to determine the performance of absolute CD4+ T-cell count estimation in guiding the clinical suspicion of co-infection. A cross-sectional survey was conducted in antiretroviral-naïve HIV (AN-HIV) patients attending an HIV outpatient clinic in Maputo city, Mozambique. Seven hundred and one AN-HIV patients were enrolled in the study. The prevalence of HTLV-1 co-infection was 4.5% (95% confidence interval [CI] 3.0-6.0%). Logistic regression analysis showed that CD4+ T-cell count was an independent predictor of co-infection (P value: 0.000). The performance of absolute CD4+ T-cell counts in predicting co-infection was higher in symptomatic HIV patients when compared with asymptomatic HIV patients. The best performance was achieved with the cut-off of CD4+ count of 500 cells/mm(3), which gave sensitivity, specificity, positive and negative predictive values of 54.2%, 87.2%, 24.0% and 96.2%, respectively. In conclusion, our data provide evidence that the absolute CD4+ T-cell count is of moderate accuracy in guiding the clinical suspicion of co-infection in AN-HIV and its implementation could improve the care provided to a significant number of HIV patients in Mozambique.

Surveillance of HIV drug resistance in children receiving antiretroviral therapy: a pilot study of the World Health Organization's generic protocol in Maputo, Mozambique.

Between 2007 and 2008, the Mozambique Ministry of Health conducted an assessment of human immunodeficiency virus drug resistance (HIVDR) using World Health Organization (WHO) methods in a cohort of children initiating antiretroviral therapy (ART) at the main pediatric ART referral center in Mozambique. It was shown that prior to ART initiation 5.4% of children had HIVDR that was associated with nevirapine perinatal exposure (P < .001). Twelve months after ART initiation, 77% had viral load suppression (<1000 copies/mL), exceeding the WHO target of ≥ 70%; 10.3% had HIVDR at 12 months. Baseline HIVDR (P = .04), maternal prevention of mother-to-child transmission (P = .02), and estimated days of missed medication (P = .03) predicted HIVDR at 12 months. As efforts to eliminate pediatric AIDS are intensified, implementation of ritonavir-boosted protease inhibitor regimens in children with prevention of mother-to-child transmission exposure may reduce risk of virological failure in our setting.

Impact of intensive care unit admission during morning bedside rounds and mortality: a multi-center retrospective cohort study.

INTRODUCTION: Recent data have suggested that patient admission during intensive care unit (ICU) morning bedside rounds is associated with less favorable outcome. We undertook the present study to explore the association between morning round-time ICU admissions and hospital mortality in a large Canadian health region. METHODS: A multi-center retrospective cohort study was performed at five hospitals in Edmonton, Canada, between July 2002 and December 2009. Round-time ICU admission was defined as occurring between 8 and 11:59 a.m. Multivariable logistic regression analysis was used to explore the association between round-time admission and outcome. RESULTS: Of 18,857 unique ICU admissions, 2,055 (10.9%) occurred during round time. Round-time admissions were more frequent in community hospitals compared with tertiary hospitals (12.0% vs. 10.5%; odds ratio [OR] 1.16; 95% CI, 1.05-1.29, P < 0.004) and from the ward compared with the emergency department (ED) or operating theater (17.5% vs. 9.2%; OR 2.1; 95% CI, 1.9-2.3, P < 0.0001). Round-time admissions were more often medical than surgical (12.6% vs. 6.6%; OR 2.06; 95% CI, 1.83-2.31, P < 0.0001), had more comorbid illness (11.9% vs. 10.5%; OR 1.15; 95% CI, 1.04-1.27, P < 0.008) and higher APACHE II score (22.2 vs. 21.3, P < 0.001), and were more likely to have a primary diagnosis of respiratory failure (37.0% vs. 31.3%, P < 0.001) or sepsis (11.1% vs. 9.0%, P = 0.002). Crude ICU mortality (15.3% vs. 11.6%; OR 1.38; 95% CI, 1.21-1.57, P < 0.0001) and hospital mortality (23.9% vs. 20.6%; OR 1.21; 95% CI, 1.09-1.35, P < 0.001) were higher for round-time compared with non-round-time admissions. In multi-variable analysis, round-time admission was associated with increased ICU mortality (OR 1.19, 95% CI, 1.03-1.38, P = 0.017) but was not significantly associated with hospital mortality (OR 1.02; 95% CI, 0.90-1.16, P = 0.700). In the subgroup admitted from the ED, round-time admission showed significantly higher ICU mortality (OR 1.54; 95% CI, 1.21-1.95; P < 0.001) and a trend for higher hospital mortality (OR 1.22; 95% CI, 0.99-1.51, P = 0.057). CONCLUSIONS: Approximately 1 in 10 patients is admitted during morning rounds. These patients are more commonly admitted from the ward and are burdened by comorbidities, are non-operative, and have higher illness severity. These patients admitted during morning rounds have higher observed ICU mortality but no difference in hospital mortality.

Histomorphometric and immunohistochemical analysis of infectious agents, T-cell subpopulations and inflammatory adhesion molecules in placentas from HIV-seropositive pregnant women.

BACKGROUND: The aim of this study was to compare histomorphometric changes and the results of immunohistochemical tests for VCAM, ICAM-1, CD4 and CD8 in normal placentas from HIV-seropositive pregnant women. METHODS: Samples of normal placentas were divided into 2 groups: healthy HIV-seronegative pregnant women (control group = C = 60) and HIV-seropositive women (experimental group = E = 57). Conventional histological sections were submitted to morphometric analysis and evaluated in terms of the immunohistochemical expression of ICAM-1, VCAM, CD4 and CD8. RESULTS: The villi in group E were smaller than those in group C. The median for the CD8+ T cell count was higher in group E than in group C (p = 0.03). Immunohistochemical expression of ICAM-1 was observed in 57% of the cases in group E, compared with 21% of those in group C (p = 0.001). There was no difference in VCAM expression or CD4+ cell counts between groups and no correlation between the data for antiretroviral therapy and morphometric or immunohistochemical data. CONCLUSIONS: The morphometric data showed that placentas of HIV-seropositive pregnant women tend to have smaller villi than those of seronegative women. In addition, immunohistochemical testing for infectious agents helped to identify cases that were positive for microorganisms (6/112) that routine pathological examination had failed to detect. The anti-p24 antibody had a limited ability to detect HIV viral protein in this study (2/57). Correlation of immunohistochemical expression of CD8+ T cells and ICAM-1 with the presence of HIV in the placenta revealed that those expressions can act as biomarkers of inflammatory changes. There was no correlation between the data for antiretroviral therapy and morphometric or immunohistochemical data.

American tegumentary leishmaniasis and HIV-AIDS association in a tertiary care center in the Brazilian Amazon.

American tegumentary leishmaniasis (ATL) and human immunodeficiency virus (HIV) are both common infectious diseases in the Brazilian Amazon with overlapping expansion areas, which leads to the occurrence of Leishmania/HIV coinfection. Most ATL/HIV-acquired immunodeficiency syndrome (AIDS) association cases have been reported from areas where Leishmania (Viannia) braziliensis is the main pathogen; this finding is in contrast with the Amazon region, where L. (V.) guyanensis is the most implicated agent, implying distinct clinical and therapeutic aspects. We describe 15 cases of ATL/HIV coinfection treated in a tertiary care center in the Brazilian Amazon between 1999 and 2008. Thirteen patients presented with diverse clinical manifestations of cutaneous leishmaniasis, and four of them had disseminated forms; two patients presented with mucosal leishmaniasis (ML). Seven patients required more than one course of treatment. The particularities of ATL/HIV-AIDS association in L. (V.) guyanensis-endemic areas require efforts for an increased understanding of its burden and subsequent improvements in case management.

Loss of correlation between HIV viral load and CD4+ T-cell counts in HIV/HTLV-1 co-infection in treatment naive Mozambican patients.

Seven hundred and four HIV-1/2-positive, antiretroviral therapy (ART) naïve patients were screened for HTLV-1 infection. Antibodies to HTLV-1 were found in 32/704 (4.5%) of the patients. Each co-infected individual was matched with two HIV mono-infected patients according to World Health Organization clinical stage, age +/-5 years and gender. Key clinical and laboratory characteristics were compared between the two groups. Mono-infected and co-infected patients displayed similar clinical characteristics. However, co-infected patients had higher absolute CD4+ T-cell counts (P = 0.001), higher percentage CD4+ T-cell counts (P < 0.001) and higher CD4/CD8 ratios (P < 0.001). Although HIV plasma RNA viral loads were inversely correlated with CD4+ T-cell-counts in mono-infected patients (P < 0.0001), a correlation was not found in co-infected individuals (P = 0.11). Patients with untreated HIV and HTLV-1 co-infection show a dissociation between immunological and HIV virological markers. Current recommendations for initiating ART and chemoprophylaxis against opportunistic infections in resource-poor settings rely on more readily available CD4+ T-cell counts without viral load parameters. These guidelines are not appropriate for co-infected individuals in whom high CD4+ T-cell counts persist despite high HIV viral load states. Thus, for co-infected patients, even in resource-poor settings, HIV viral loads are likely to contribute information crucial for the appropriate timing of ART introduction.

Application of the comet assay in erythrocytes of Oreochromis niloticus (Pisces): A methodological comparison.

The present study applied the comet assay to erythrocytes of Oreochromis niloticus with the aim of improving protocols to detect DNA damage in these cells, by using two distinct pHs (pH = 12.1 and pH > 13) and evaluating whether there is a correspondence between silver and ethidium bromide staining. Comets were visually examined and, the frequency of cells with and without damage was obtained, as well as the distribution of classes and scores. By using the Kruskal-Wallis test, our results revealed that pH 12.1 is more effective, although both pHs can be used. Our findings also suggest that silver staining can substitute ethidium bromide, an expensive and highly toxic stain that requires specific equipment for examination.

Application of the comet assay in erythrocytes of Oreochromis niloticus (Pisces): a methodological comparison

The present study applied the comet assay to erythrocytes of Oreochromis niloticus with the aim of improving protocols to detect DNA damage in these cells, by using two distinct pHs (pH = 12.1 and pH > 13) and evaluating whether there is a correspondence between silver and ethidium bromide staining. Comets were visually examined and, the frequency of cells with and without damage was obtained, as well as the distribution of classes and scores. By using the Kruskal-Wallis test, our results revealed that pH 12.1 is more effective, although both pHs can be used. Our findings also suggest that silver staining can substitute ethidium bromide, an expensive and highly toxic stain that requires specific equipment for examination.