The epidemiology of acute respiratory failure in hospitalized patients: A Brazilian prospective cohort study

Purpose: The purpose of this study was to assess risk factors associated with the development of acute respiratory failure (ARF) and death in a general intensive care unit (ICU). Materials and Methods: Adults who were hospitalized at 12 surgical and nonsurgical ICUs were prospectively followed up. Multivariable analyses were realized to determine the risk factors for ARF and point out the prognostic factors for mortality in these patients. Results: A total of 1732 patients were evaluated, with an ARF prevalence of 57%. Of the 889 patients who were admitted without ARF, 141 (16%) developed this syndrome in the ICU. The independent risk factors for developing ARF were 64 years of age or older, longer time between hospital and ICU admission, unscheduled surgical or clinical reason for ICU admission, and severity of illness. Of the 984 patients with ARF, 475 (48%) died during the ICU stay. Independent prognostic factors for death were age older than 64 years, time between hospital and ICU admission of more than 4 days, history of hematologic malignancy or AIDS, the development of ARF in ICU, acute lung injury, and severity of illness. Conclusions: Acute respiratory failure represents a large percentage of all ICU patients, and the high mortality is related to some preventable factors such as the time to ICU admission. (C) 2011 Elsevier Inc. All rights reserved.

Epidemiology of urogenital tuberculosis worldwide

Objectives: To characterize the epidemiology of urogenital tuberculosis worldwide and to compare the features of patients from developing countries to those from developed countries. Methods: A comprehensive search of articles published up to April 2008 using a combination of the terms `tuberculosis`, `genitourinary`, `renal` and `urogenital` was performed. Results: Urogenital tuberculosis affects more men than women (2:1), with a mean age of 40.7 years (range 5-90). In 26.9% of cases there is a non-functioning unilateral kidney and in 7.4%, renal failure. Patients from developing countries are more likely to have a delayed diagnosis with a higher frequency of renal failure, unilateral non-functioning kidney, ablative surgery and contracted bladder. Conclusions: Urogenital tuberculosis is a worldwide disease with more destructive behavior in developing countries where urgent strategies for early detection are particularly warranted.

Epidemiology of meningococcal disease in Latin America: current situation and opportunities for prevention

Objective: Meningococcal disease continues to be a serious public health concern, being associated with high morbidity and mortality rates in many countries from Latin America. In addition to discussing recent changes in the epidemiology of meningococcal disease in the region, we also analyse the development and potential impact of new vaccines on the prevention of meningococcal disease. Methods: MEDLINE, SciELO, LILACS and websites of the national Ministries of Health databases were searched using the terms meningococcal disease, meningococcal epidemiology, Neisseria meningitidis, meningococcal vaccines and the name of Latin America countries, from 1998 to 2008, with emphasis on review articles, clinical trials and epidemiological studies. Results: Epidemiology of meningococcal disease in Latin America is characterized by marked differences from country to country. The overall incidence of meningococcal disease per year varied from less than 0.1 cases per 100,000 inhabitants in countries like Mexico to two cases per 100,000 inhabitants in Brazil. The highest age-specific incidence of meningococcal disease occurred in infants less than 1 year of age. Serogroups B and C were responsible for the majority of cases reported, but the emergence of serogroups W135 and Y was reported in some countries. Serogroup A disease is now rare in Latin America. Discussion: Although a few countries have established meningitis surveillance programs, the information is not uniform, and the quality of the reported data is poor in the majority of the region. The availability of new effective meningococcal conjugate vaccines and promising protein-based vaccine candidates against meningococcus B highlights the importance of a better understanding of the true burden of meningococcal disease in Latin America and also the need for cost-effectiveness studies before incorporating the new meningococcal vaccines to national immunization programs.

Epidemiology of Spondyloarthritis in Brazil

During the period of 2006 to 2007, 28 university centers in Brazil used a standardized protocol of investigation to study the epidemiological, clinical and radiological variables of 1036 consecutive patients with the diagnosis of spondyloarthritis (SpA). Validated translated (Portuguese) versions of the Bath Ankylosing Spondylitis (AS) Disease Activity Index and the Bath AS Functional Index were applied. Patient diagnoses were predominantly AS (72.3%), followed by psoriatic arthritis (13.7%), undifferentiated SpA (6.3%), reactive arthritis (3.6%), juvenile SpA (3.1%) and arthritis related to inflammatory bowel disease (1.0%). There was a predominance of male (73.6%) and white (59.5%) patients. Pure axial disease was observed in 36.7% of the patients, whereas the mixed pattern (axial, peripheral and entheseal) was observed in 47.9%. The most common extra-articular involvement was anterior uveitis (20.2%). HLA-B27 was positive in 69.5% of the tested patients.

Rabies virus in insectivorous bats: Implications of the diversity of the nucleoprotein and glycoprotein genes for molecular epidemiology

Insectivorous bats are the main reservoirs of rabies virus (RABV) in various regions of the world. The aims of this study were to (a) establish genealogies for RABV strains from different species of Brazilian insectivorous bats based on the nucleoprotein (N) and glycoprotein (G) genes, (b) investigate specific RABV lineages associated with certain genera of bats and (c) identify molecular markers that can distinguish between these lineages. The genealogic analysis of N and G from 57 RABV strains revealed seven genus-specific clusters related to the insectivorous bats Myotis, Eptesicus, Nyctinomops, Molossus, Tadarida, Histiotus and Lasiurus. Molecular markers in the amino acid sequences were identified which were specific to the seven clusters. These results, which constitute a novel finding for this pathogen, show that there are at least seven independent epidemiological rabies cycles maintained by seven genera of insectivorous bats in Brazil. (C) 2010 Elsevier Inc. All rights reserved.

Molecular Epidemiology of Avian Infectious Bronchitis in Brazil from 2007 to 2008 in Breeders, Broilers, and Layers

Multiple lineages of Brazilian strains from 2007 to 2008 of avian infectious bronchitis virus (IBV) were detected in flocks of breeders, broilers, and layers. Organs samples from 20 IBV-positive flocks with variable clinical signs were submitted to the partial amplification of S gene (nucleotides 726-1071) of IBV. Fifteen of the 20 sequenced strains segregated in a unique Brazilian cluster subdivided in three subclusters (Brazil 01, 02, and 03). Whereas three strains could be classified as Massachusetts (Mass) genotype, the remaining two strains, originating from flocks with reproductive and respiratory disorders, grouped within the 4/91-793B genotype, a genotype that has not been detected before in Brazil. The potential relevance of the findings to the poultry industry is discussed because the low level of identity of the sequenced part of the S gene from 17 of 20 detected field strains and the vaccines of the Massachusetts serotype used suggest that the level of cross-protection by the Massachusetts vaccines might be low.

Epidemiology and Genetic Variability of Human Metapneumovirus During a 4-Year-Long Study in Southeastern Brazil

Epidemiological and molecular characteristics of human metapneumovirus (hMPV) were compared with human respiratory syncytial virus (hRSV) in infants and young children admitted for acute lower respiratory tract infections in a prospective study during four consecutive years in subtropical Brazil. GeneScan polymerase chain assays (GeneScan RT-PCR) were used to detect hMPV and hRSV in nasopharyngeal aspirates of 1,670 children during January 2003 to December 2006. hMPV and hRSV were detected, respectively, in 191 (11.4%) and in 702 (42%) of the children admitted with acute lower respiratory tract infections at the Sao Paulo University Hospital. Sequencing data of the hMPV F gene revealed that two groups of the virus, each divided into two subgroups, co-circulated during three consecutive years. It was also shown that a clear dominance of genotype B1 occurred during the years 2004 and 2005, followed by genotype A2 during 2006. J. Med. Virol. 81:915-921,2009. (C) 2009 Wiley-Liss, Inc.

Epidemiology and control of frontier malaria in Brazil: lessons from community-based studies in rural Amazonia

We describe the epidemiology of malaria in a frontier agricultural settlement in Brazilian Amazonia. We analysed the incidence of slide-confirmed symptomatic infections diagnosed between 2001 and 2006 in a cohort of 531 individuals (2281.53 person-years of follow-up) and parasite prevalence data derived from four cross-sectional surveys. Overall, the incidence rates of Plasmodium vivax and P. falciparaum were 20.6/100 and 6.8/100 person-years at risk, respectively, with a marked decline in the incidence of both species (81.4 and 56.8%, respectively) observed between 2001 and 2006. PCR revealed 5.4-fold more infections than conventional microscopy in population-wide cross-sectional surveys carried out between 2004 and 2006 (average prevalence, 11.3 vs. 2.0%). Only 27.2% of PCR-positive (but 73.3% of slide-positive) individuals had symptoms when enrolled, indicating that asymptomatic carriage of low-grade parasitaemias is a common phenomenon in frontier settlements. A circular cluster comprising 22.3% of the households, all situated in the area of most recent occupation, comprised 69.1% of all malaria infections diagnosed during the follow-up, with malaria incidence decreasing exponentially with distance from the cluster centre. By targeting one-quarter of the households, with selective indoor spraying or other house-protection measures, malaria incidence could be reduced by more than two-thirds in this community. (C) 2010 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.

A nonlinear regression model with skew-normal errors

In this paper we have discussed inference aspects of the skew-normal nonlinear regression models following both, a classical and Bayesian approach, extending the usual normal nonlinear regression models. The univariate skew-normal distribution that will be used in this work was introduced by Sahu et al. (Can J Stat 29:129-150, 2003), which is attractive because estimation of the skewness parameter does not present the same degree of difficulty as in the case with Azzalini (Scand J Stat 12:171-178, 1985) one and, moreover, it allows easy implementation of the EM-algorithm. As illustration of the proposed methodology, we consider a data set previously analyzed in the literature under normality.

Hypotheses Testing on a Multivariate Null Intercept Errors-in-Variables Model

Considering the Wald, score, and likelihood ratio asymptotic test statistics, we analyze a multivariate null intercept errors-in-variables regression model, where the explanatory and the response variables are subject to measurement errors, and a possible structure of dependency between the measurements taken within the same individual are incorporated, representing a longitudinal structure. This model was proposed by Aoki et al. (2003b) and analyzed under the bayesian approach. In this article, considering the classical approach, we analyze asymptotic test statistics and present a simulation study to compare the behavior of the three test statistics for different sample sizes, parameter values and nominal levels of the test. Also, closed form expressions for the score function and the Fisher information matrix are presented. We consider two real numerical illustrations, the odontological data set from Hadgu and Koch (1999), and a quality control data set.

Nonlinear refractive index of RECOB (RE = Gd and La) crystals

The Z-scan technique is employed to obtain the nonlinear refractive index (n (2)) of the Ca(4)REO(BO(3))(3) (RECOB, where RE = Gd and La) single crystals using 30 fs laser pulses centered at 780 nm for the two orthogonal orientations determined by the optical axes (X and Z) relative to the direction of propagation of the laser beam (k//Y// crystallographic b-axis). The large values of n (2) indicate that both GdCOB and LaCOB are potential hosts for Yb:RECOB lasers operating in the Kerr-lens mode locking (KLM) regime.

Time-resolved study electronic and thermal contributions to the nonlinear refractive index of Nd3+: SBN laser crystals

The propagation of an optical beam through dielectric media induces changes in the refractive index, An, which causes self-focusing or self-defocusing. In the particular case of ion-doped solids, there are thermal and non-thermal lens effects, where the latter is due to the polarizability difference, Delta alpha, between the excited and ground states, the so-called population lens (PL) effect. PL is a pure electronic contribution to the nonlinearity, while the thermal lens (TL) effect is caused by the conversion of part of the absorbed energy into heat. In time-resolved measurements such as Z-scan and TL transient experiments, it is not easy to separate these two contributions to nonlinear refractive index because they usually have similar response times. In this work, we performed time-resolved measurements using both Z-scan and mode mismatched TL in order to discriminate thermal and electronic contributions to the laser-induced refractive index change of the Nd3+-doped Strontium Barium Niobate (SrxBa1-xNb2O6) laser crystal. Combining numerical simulations with experimental results we could successfully distinguish between the two contributions to An. (C) 2007 Elsevier B.V. All rights reserved.

A multivariate ultrastructural errors-in-variables model with equation error

This paper deals with asymptotic results on a multivariate ultrastructural errors-in-variables regression model with equation errors Sufficient conditions for attaining consistent estimators for model parameters are presented Asymptotic distributions for the line regression estimators are derived Applications to the elliptical class of distributions with two error assumptions are presented The model generalizes previous results aimed at univariate scenarios (C) 2010 Elsevier Inc All rights reserved

Bayesian Analysis for Nonlinear Regression Model Under Skewed Errors, with Application in Growth Curves

We have considered a Bayesian approach for the nonlinear regression model by replacing the normal distribution on the error term by some skewed distributions, which account for both skewness and heavy tails or skewness alone. The type of data considered in this paper concerns repeated measurements taken in time on a set of individuals. Such multiple observations on the same individual generally produce serially correlated outcomes. Thus, additionally, our model does allow for a correlation between observations made from the same individual. We have illustrated the procedure using a data set to study the growth curves of a clinic measurement of a group of pregnant women from an obstetrics clinic in Santiago, Chile. Parameter estimation and prediction were carried out using appropriate posterior simulation schemes based in Markov Chain Monte Carlo methods. Besides the deviance information criterion (DIC) and the conditional predictive ordinate (CPO), we suggest the use of proper scoring rules based on the posterior predictive distribution for comparing models. For our data set, all these criteria chose the skew-t model as the best model for the errors. These DIC and CPO criteria are also validated, for the model proposed here, through a simulation study. As a conclusion of this study, the DIC criterion is not trustful for this kind of complex model.

Influence diagnostics for linear models with first-order autoregressive elliptical errors

We introduce in this paper the class of linear models with first-order autoregressive elliptical errors. The score functions and the Fisher information matrices are derived for the parameters of interest and an iterative process is proposed for the parameter estimation. Some robustness aspects of the maximum likelihood estimates are discussed. The normal curvatures of local influence are also derived for some usual perturbation schemes whereas diagnostic graphics to assess the sensitivity of the maximum likelihood estimates are proposed. The methodology is applied to analyse the daily log excess return on the Microsoft whose empirical distributions appear to have AR(1) and heavy-tailed errors. (C) 2008 Elsevier B.V. All rights reserved.