The effect of acute magnesium loading on the maximal exercise performance of stable chronic obstructive pulmonary disease patients

OBJECTIVE: The potential influence of magnesium on exercise performance is a subject of increasing interest. Magnesium has been shown to have bronchodilatatory properties in asthma and chronic obstructive pulmonary disease patients. The aim of this study was to investigate the effects of acute magnesium IV loading on the aerobic exercise performance of stable chronic obstructive pulmonary disease patients. METHODS: Twenty male chronic obstructive pulmonary disease patients (66.2 + 8.3 years old, FEV1: 49.3+19.8%) received an IV infusion of 2 g of either magnesium sulfate or saline on two randomly assigned occasions approximately two days apart. Spirometry was performed both before and 45 minutes after the infusions. A symptom-limited incremental maximal cardiopulmonary test was performed on a cycle ergometer at approximately 100 minutes after the end of the infusion. ClinicalTrials.gov: NCT00500864 RESULTS: Magnesium infusion was associated with significant reductions in the functional residual capacity (-0.41 l) and residual volume (-0.47 l), the mean arterial blood pressure (-5.6 mmHg) and the cardiac double product (734.8 mmHg.bpm) at rest. Magnesium treatment led to significant increases in the maximal load reached (+8 w) and the respiratory exchange ratio (0.06) at peak exercise. The subgroup of patients who showed increases in the work load equal to or greater than 5 w also exhibited significantly greater improvements in inspiratory capacity (0.29 l). CONCLUSIONS: The acute IV loading of magnesium promotes a reduction in static lung hyperinflation and improves the exercise performance in stable chronic obstructive pulmonary disease patients. Improvements in respiratory mechanics appear to be responsible for the latter finding

Atopy risk factors at birth and in adulthood

OBJETIVO: Estudar a associação entre atopia e variáveis como peso, comprimento e nível socioeconômico no nascimento e na idade adulta jovem. MÉTODOS: Foram investigados 2.063 indivíduos em um estudo prospectivo de coorte de nascimento com indivíduos nascidos em Ribeirão Preto (SP), em 1978/1979, e examinados aos 23-25 anos de idade. Realizaram-se testes cutâneos de puntura (TCP) para oito alérgenos comuns no Brasil. Foram considerados atópicos os indivíduos que apresentaram reação papular > 3 mm para um ou mais dos oito alérgenos testados. A fim de avaliar a associação entre atopia e variáveis no nascimento e na idade adulta, utilizamos o modelo log-binomial (modelo linear generalizado). RESULTADOS: A prevalência de TCP positivo foi de 47,6%. O gênero masculino esteve associado a aumento do risco de atopia [risco relativo (RR) = 1,18; intervalo de confiança de 95% (IC95%) 1,07-1,30]. O baixo nível de escolaridade foi um fator de proteção contra atopia, com um RR = 0,74; IC95% 0,62-0,89. A convivência com um fumante na infância também esteve associada a um menor risco de atopia (RR = 0,87; IC95% 0,79-0,96). Peso e comprimento ao nascer, ordem de nascimento, idade materna e restrição de crescimento intrauterino não estiveram associados a TPC positivo. CONCLUSÕES: Este estudo demonstrou que o gênero masculino esteve associado a um aumento do risco de atopia. O baixo nível socioeconômico, estabelecido pelo baixo nível de escolaridade, foi um fator de proteção contra a atopia. Esses dados estão de acordo com a teoria da higiene.OBJECTIVE: To study the association between atopy and variables such as weight, length, and socioeconomic level at birth and in young adulthood. METHODS: A total of 2,063 subjects were investigated in a prospective birth cohort study of individuals born in Ribeirão Preto, Brazil, in 1978/1979, and examined at the age of 23-25 years. Skin prick tests (SPT) for eight common allergens in Brazil were performed. Subjects with a wheal reaction > 3 mm to one or more of the eight allergens tested were considered to be atopic. We used the log-binomial model (generalized linear model) in order to assess the association between atopy and birth or adult variables. RESULTS: The prevalence of positive SPT was 47.6%. Male gender was associated with an increased risk of atopy (relative risk [RR] = 1.18; 95% confidence interval [95%CI] 1.07-1.30). Low level of schooling was a protective factor against atopy, with a RR = 0.74; 95%CI 0.62-0.89. Living with a smoker in childhood was also associated with lower risk of atopy (RR = 0.87; 95%CI 0.79-0.96). Birth weight, length and order, maternal age, and intrauterine growth restriction were not associated with positive SPT. CONCLUSIONS: This study showed that male gender was associated with an increased risk of atopy. Low socioeconomic status, assessed by low level of schooling, was a protective factor against atopy. These data agree with the hygiene hypothesis

Exposure to high endotoxin concentration increases wheezing prevalence among laboratory animal workers: a cross-sectional study

Background: Endotoxin from Gram-negative bacteria are found in different concentrations in dust and on the ground of laboratories dealing with small animals and animal houses. Methods: Cross-sectional study performed in workplaces of two universities. Dust samples were collected from laboratories and animal facilities housing rats, mice, guinea pigs, rabbits or hamsters and analyzed by the "Limulus amebocyte lysate" (LAL) method. We also sampled workplaces without animals. The concentrations of endotoxin detected in the workplaces were tested for association with wheezing in the last 12 months, asthma defined by self-reported diagnosis and asthma confirmed by bronchial hyperresponsiveness (BHR) to mannitol. Results: Dust samples were obtained at 145 workplaces, 92 with exposure to animals and 53 with no exposure. Exposed group comprised 412 subjects and non-exposed group comprised 339 subjects. Animal-exposed workplaces had higher concentrations of endotoxin, median of 34.2 endotoxin units (EU) per mg of dust (interquartile range, 12.6-65.4), as compared to the non-exposed group, median of 10.2 EU/mg of dust (interquartile range, 2.6-22.2) (p < 0.001). The high concentration of endotoxin (above whole sample median, 20.4 EU/mg) was associated with increased wheezing prevalence (p < 0.001), i.e., 61 % of workers exposed to high endotoxin concentration reported wheezing in the last 12 months compared to 29 % of workers exposed to low endotoxin concentration. The concentration of endotoxin was not associated with asthma report or with BHR confirmed asthma. Conclusion: Exposure to endotoxin is associated with a higher prevalence of wheezing, but not with asthma as defined by the mannitol bronchial challenge test or by self- reported asthma. Preventive measures are necessary for these workers16CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informaçã

Influence of asthma definition on the asthma-obesity relationship

Background: Epidemiological studies suggest an association between obesity and asthma in adults and children. Asthma diagnosis criteria are different among studies. The aim of this study was to test the influence of asthma definition on the asthma-obesity relationship. Methods: In a cross-sectional analysis of 1922 men and women, subjects completed a translated questionnaire from the European Community Respiratory Health Survey and underwent spirometry and a bronchial challenge test. Weight, height and waist circumference were measured. Multiple logistic regression analysis was carried out to assess the association of variables related to obesity and asthma. Asthma was defined either by the presence of symptoms with bronchial hyperresponsiveness (BHR) or by a self-report of a physician-made diagnosis. The following variables were separately tested for associations with asthma: socioeconomic characteristics, schooling, physical activity, smoking status, anthropometry and spirometry. Results: No association was detected between asthma confirmed by BHR and obesity indicators, odds ratio (OR) = 1.08 (95% confidence interval: 0.69 - 1.68) for obesity assessed by body mass index &gt;= 30 kg/m(2); OR = 1.02 (0.74 - 1.40) for obesity assessed by abnormal waist-to-height ratio; and, OR = 0.96 (0.69 - 1.33) for abnormal waist circumference. On the contrary, a previous diagnosis of asthma was associated with obesity, OR = 1.48 (1.01 - 2.16) for body mass index &gt;= 30 kg/m(2); OR = 1.48 (1.13 - 1.93) for abnormal waist-to-height ratio; and, OR = 1.32 (1.00 - 1.75) for abnormal waist circumference. Female gender, schooling &gt;= 12 years and smoking were associated with BHR-confirmed asthma. Physically inactive subjects were associated with a previous diagnosis of asthma. Conclusions: Our findings indicate that the relationship between asthma and obesity in epidemiological studies depends on the definition adopted. Certain components of asthma, for instance, symptoms may be more prone to the obesity influence than other ones, like bronchial hyperresponsiveness.FAPESPFAPES

Ensino do exame respiratório: o que é história e o que é necessidade?

A semiologia é uma das técnicas mais utilizadas na prática médica há séculos. Ensinada por meio de roteiros sistematizados, estudantes de inúmeras escolas da área de saúde por todo o mundo aprendem as manobras semiológicas como fundamento na avaliação dos pacientes. No entanto, apesar de extremamente difundida, discute-se pouco sobre sua acurácia como manobra diagnóstica. Tendo este ponto em vista, este artigo aborda a precisão das diversas manobras semiológicas do exame físico do aparelho respiratório e a descrição comparativa do seu ensino em diferentes escolas médicas no mundo. Como resultados, tem-se valores de acurácia discordantes, o que pode ser justificado pela qualidade dos estudos ou pelas variáveis analisadas que diferem entre os estudos e propostas de padronização. Em conclusão, a semiologia é a base da avaliação médica, independentemente dos avanços e disponibilidade dos exames de imagens, e cada manobra deve ser ensinada com seu devido valor científico. Conhecer a aplicabilidade e individualizar a prática das etapas do exame respiratório pode ser um caminho possível de adequação aos tempos atuais, sem impor perdas de informações relevantes para o desenvolvimento do raciocínio clínico.Medical semiology has been one of the most common techniques used in medical practice for centuries. Health science students around the globe learn these techniques through a systematized model as a fundamental skill for patient evaluation. However, though being widespread, little is known about semiology’s true accuracy as a diagnostic maneuver. Knowing that, through a literature review, this paper evaluated the precision of the preconized procedures that are used as part of the exam of the respiratory system and the comparative description of its teaching in different medical schools around the world. As a result, disagreement between several papers was found, which can be justified by the poor quality of the studies and the different variables that were studied in each one. However, one thing is still clear:  respiratory physical examination continues to be essential in medical practice, independently of the recent advances and availability of imaging exams. Teaching each step should consider available scientific evidence. The knowledge of the applicability and practical individualization of the respiratory examination can be a possible way for the current times without missing relevant information for developing clinical reasoning

Insulin modulates cytokine release and selectin expression in the early phase of allergic airway inflammation in diabetic rats

<p>Abstract</p> <p>Background</p> <p>Clinical and experimental data suggest that the inflammatory response is impaired in diabetics and can be modulated by insulin. The present study was undertaken to investigate the role of insulin on the early phase of allergic airway inflammation.</p> <p>Methods</p> <p>Diabetic male Wistar rats (alloxan, 42 mg/Kg, i.v., 10 days) and controls were sensitized by s.c. injection of ovalbumin (OA) in aluminium hydroxide 14 days before OA (1 mg/0.4 mL) or saline intratracheal challenge. The following analyses were performed 6 hours thereafter: a) quantification of interleukin (IL)-1β, tumor necrosis factor (TNF)-α and cytokine-induced neutrophil chemoattractant (CINC)-1 in the bronchoalveolar lavage fluid (BALF) by Enzyme-Linked Immunosorbent Assay, b) expression of E- and P- selectins on lung vessels by immunohistochemistry, and c) inflammatory cell infiltration into the airways and lung parenchyma. NPH insulin (4 IU, s.c.) was given i.v. 2 hours before antigen challenge.</p> <p>Results</p> <p>Diabetic rats exhibited significant reduction in the BALF concentrations of IL-1β (30%) and TNF-α (45%), and in the lung expression of P-selectin (30%) compared to non-diabetic animals. This was accompanied by reduced number of neutrophils into the airways and around bronchi and blood vessels. There were no differences in the CINC-1 levels in BALF, and E-selectin expression. Treatment of diabetic rats with NPH insulin, 2 hours before antigen challenge, restored the reduced levels of IL-1β, TNF-α and P-selectin, and neutrophil migration.</p> <p>Conclusion</p> <p>Data presented suggest that insulin modulates the production/release of TNF-α and IL-1β, the expression of P- and E-selectin, and the associated neutrophil migration into the lungs during the early phase of the allergic inflammatory reaction.</p