Efeitos da administração sistemica de corticosteroide sobre propriedades mecanicas musculares / Effects of systemic corticosteroid administration on mechanical muscle properties

Costicosteroides sistemicos em altas doses podem causar miopatia metabolica. O Objetivo deste estudo foi valiar, por meio de ensaios de tracao, os efeitos da miopatia induzida por corticosteroides nas propriedades mecanicas do musculo gastrocnemio medial de coelhos. Foram estudados dois grupos de 15 coelhas da raca Nova Zelandia: grupo experimental (GE), que recebeu injecoes subcutaneas de metil-prednisolona (2mg/kg/dia), e grupo-controle (GC), que recebeu solucao fisiologica por via subcutanea. Os grupos foram tratados por 21 dias. Foram feitos ensaios de tracao nos musculos gastrocnemios mediais esquerdos. Resultados: o peso final dos animais do GE foi 3,6+-0,1kg e do GC, 40+-0,1kg. O peso final do gastrocnemio do GE foi 5,6+-1,0g e do GC, 7,0+-1,3g. Os valores de area, largura e espessura do gastrocnemio...

Rapid effect of inhaled steroids on nocturnal worsening of asthma.

BACKGROUND: Inhaled steroids are the most commonly used anti-inflammatory agents for asthma and are increasingly recognised as having a more rapid onset of action than was previously thought. We have investigated the effect of a single dose of inhaled steroid on nocturnal worsening of asthma. METHODS: Ten patients with steroid naive moderate asthma and nocturnal asthma participated in a randomised, double blind, placebo controlled, crossover trial. Participants spent three nights in the laboratory, one week apart. On each night they underwent spirometric testing at 16.00 hours and received one of the three treatments (placebo, beclomethasone 1000 micro g, or fluticasone 1000 micro g) delivered by metered dose inhaler. Spirometric tests were repeated at 04.00 hours the following morning. RESULTS: Following placebo administration the mean (SE) overnight fall in FEV(1) was 0.65 (0.27) l compared with -0.02 (0.13) l following fluticasone (p=0.019) and 0.23 (0.12) l following beclomethasone (p=0.048 v placebo). CONCLUSION: A single dose of inhaled steroid (within the therapeutic range) reduced the fall in FEV(1) in patients with nocturnal asthma when administered at 16.00 hours. Nocturnal worsening of asthma is a useful model for testing inhaled steroid activity in a single night study.

Do steroids interfere in dyspnoea sensation?

Dyspnoea remains a remarkable clinical problem and a therapeutic challenge, mainly in chronic respiratory conditions. This study investigated the potential effects of steroids on dyspnoea sensation regardless of their pulmonary anti-inflammatory actions. Sixteen healthy men (mean age +/- SD = 22.5 +/- 1.6 years) developed uncomfortable breathing by the use of inspiratory resistors (loads of 0, 7, 14 and 21 cm H2O/l/s) and breathholding 6 h after taking 40 mg of prednisone (Pred) or placebo (Plac). Respiratory discomfort during breathing with loads was evaluated with a 100 mm visual analog scale. The maximum voluntary apnoea time did not differ between the prednisone and placebo days (Plac = 96 +/- 11.8 s x Pred = 105 +/- 12.2 s) and prednisone did not influence the dyspnoea sensation induced by different inspiratory loads (0 cm H2O/l/s: Pred = 2.8 mm x Plac = 1.9 mm; 7 cm H2O/l/s: Pred = 18.3 mm x Plac = 18.6 mm; 14 cm H2O/l/s; Pred = 33.0 mm x Plac = 34.1 mm; 21 cm H2O/l/s: Pred = 48.1 mm x Plac = 49.6 mm). Prednisone intake was associated with a significant increase in minute ventilation during breathing with no inspiratory loads (Pred = 11.91 +/- 1.28 l/min- x Plac = 9.95 +/- 0.86 l/min). Although steroids certainly may improve respiratory conditions due to anti-inflammatory actions, available evidence does not support any specific beneficial effect of these drugs on these perception of dyspnoea itself.