Diurnal variations of acute mountain sickness, colour vision, and plasma cortisol and ACTH at high altitude.

Time dependence of colour vision in the green/red axis, signs of acute mountain sickness (AMS), and plasma cortisol and ACTH concentrations were studied in eight sea-level male natives exposed 79 h to altitude hypoxia at 4,350 m. Colour vision (CV) was explored every 2 h from 08:00 to 20:00 hours by means of two portable anomaloscopes, one derived from Essilor CHROMOTEST and the other from the OSCAR. Significant diurnal variations in CV were found using both anomaloscopes, major alterations in green relative to red sensitivity being seen in the early morning. AMS scores also showed remarkable diurnal variations, parallel to those of plasma cortisol and CV, with maximum values observed at 08:00 hours. Cortisol diurnal rhythm was maintained in hypoxia, with mean concentrations higher than in normoxia. ACTH followed the same trend, but variations were not significant. Significant correlations were found between instant values of CV, cortisol, and AMS score, but no causal relationship between these variables can be ascertained.

Modification of colour vision in the green/red axis in acute and chronic hypoxia explored with a portable anomaloscope.

The effects of acute (4350 m), subacute (4800 m) and chronic (4800 m) altitude hypoxia on colour vision in the green/red axis were explored in eight sea-level natives by means of a simple portable anomaloscope. Subjects were required to create a yellow colour from a mixture of red (635 nm) and green (565 nm) obtained from two electroluminescent diodes. A relative decrease in green, compared to red, sensitivity was observed in each hypoxic condition (p less than 0.001). Acclimatization to altitude, evidenced by the improvement of arterial O2 saturation (earoximeter) was accompanied by a slight but not significant return to normal colour sensitivities. The influence of factors such as fatigue, season, and age is discussed and does not seem likely to account for the observed variations.

A combination of amoxicillin and clavulanic acid in the treatment of respiratory tract infections caused by amoxicillin-resistant haemophilus influenzae.

This study was undertaken to evaluate the efficacy of a fixed combination of amoxicillin and clavulanic acid in 33 patients with chronic or recurrent respiratory tract infections (R.T.I.), mainly bronchitis. In two patients bronchopneumonia was diagnosed, and in one cystic fibrosis. The patients were treated with 750 mg of the drug combination (500 mg amoxicillin/250 mg clavulanic acid) t. i. d. for seven or ten days. Good clinical success was obtained in 17 patients and a clear improvement in another eight. The most frequently isolated micro-organism was Haemophilus influenzae; of the 22 strains isolated, 20 were resistant to 2 mg/l amoxicillin but sensitive to the combination of 2 mg/l amoxicillin and 1 mg/l clavulanic acid. Side-effects were reported in nine patients; two patients discontinued treatment for this reason. Amoxicillin/clavulanic acid is a useful therapeutic addition to the existing forms of treatment for amoxicillin-resistant respiratory tract infections.