ABSTRACT
ß2-Adrenergic receptor agonists are believed to present with ergogenic properties. However, how combined respiratory, cardiovascular and muscular effects of these drugs might affect exercise capacity remain incompletely understood. The effects of salbutamol were investigated in 23 healthy subjects. The study was randomised, placebo-controlled in double-blind and followed a cross-over design. Salbutamol was given at the dose of 10 µg/min in 11 subjects and 20 µg/min iv in the other 12 subjects. Measurements included muscle sympathetic nerve activity (MSNA), ventilatory responses to hyperoxic hypercapnia (7% CO(2) in O(2,) central chemoreflex), isocapnic hypoxia (10% O(2) in N(2), peripheral chemoreflex) and isometric muscle contraction followed by a local circulatory arrest (metaboreflex), cardiopulmonary exercise test (CPET) variables and isokinetic muscle strength. Salbutamol 10 µg/min increased heart rate and blood pressure, while MSNA burst frequency remained unchanged. Peripheral chemosensitivity increased, as evidenced by an increased ventilatory response to hypoxia, but ventilatory responses to hypercapnia or muscle ischaemia remained unchanged. The effects of salbutamol 20 µg/min were similar. Both doses of salbutamol did not affect CPET. Only the higher dose of salbutamol decreased the anaerobic threshold, but this was not associated with a change in VO(2) max. Salbutamol increased the slopes of ventilation as a function of VO(2) (P < 0.05) and VCO(2) (P < 0.001) during CPET. Maximal isokinetic muscle strength was not affected by salbutamol. In conclusion, the acute administration of either low or high dose salbutamol does not affect exercise capacity in normal subjects, in spite of an earlier anaerobic threshold and increased chemosensitivity.
Subject(s)
Adrenergic beta-2 Receptor Agonists/pharmacology , Albuterol/pharmacology , Athletic Performance , Exercise Tolerance/drug effects , Adult , Athletic Performance/physiology , Cross-Over Studies , Double-Blind Method , Exercise/physiology , Exercise Test , Exercise Tolerance/physiology , Health , Humans , Male , Muscle, Skeletal/drug effects , Muscle, Skeletal/innervation , Placebos , Pulmonary Ventilation/drug effects , Pulmonary Ventilation/physiology , Receptors, Adrenergic, beta-2/metabolism , Sympathetic Nervous System/drug effects , Sympathetic Nervous System/physiology , Young AdultABSTRACT
The classical clinical picture of amoebic infection of the liver consists of fever, right upper quadrant pain and hepatomegaly. In recent years, the widespread availability of ultrasound and serology made an early diagnosis possible, which could result in less prominent clinical pictures. Thirty six cases of liver amoebiasis diagnosed in Antwerp between 1985 and 1992, were reviewed. Three patients acquired their infection in Belgium. For the other patients, the average delay between arrival in Belgium and the first symptoms was 5.64 months. The classical triad of clinical signs (fever, right upper quadrant pain and hepatomegaly), was observed in only 13.9% of the patients, whereas it was much more frequent in earlier studies (68-75%). The right lobe was the most frequently affected (94%). The colour of the liquid, obtained by puncture, was brown in 61% of patients in whom it was reported. Amoebic cysts were found in the stools of only one patient. Amoebic serology was initially negative in only one patient, but became positive on second testing. Chest X-rays were abnormal in 34% of the patients. All patients who develop unexplained fever during the year after a stay in tropical countries should undergo an abdominal ultrasound examination and serological testing for Entamoeba histolytica.
