Prevalence of asthma: a comparative study of urban and rural Xhosa children

An epidemiological study was undertaken to determine the prevalence of asthma in young urban and rural black (Xhosa) children. One thousand three hundred and seventy five children were studied, 694 from a Cape Town african township and 671 from a rural area in Transkei. The exercise tolerance test which required free range running at maximum effort for 6 min was used to identify asthmatic subjects. A fall of 15% or more in the post-exercise FEV₁ and PEFR values was regarded as a positive result. Twenty-three children were found to be asthmatic, twenty-two from the city area, but only one from the country, giving a prevalence figure for asthma of 3.17% in the first group and 0.14% for the second. Possible reasons for these differences are discussed. The exercise tolerance test was found to be a useful tool for epidemiological studies of asthma.     

AA glomerular amyloid. An ultrastructural immunogold study of the colocalization of heparan sulphate proteoglycan and P component with amyloid fibrils together with changes in distribution of type IV collagen and fibronectin

An ultrastructural investigation was undertaken on paraformaldehyde-fixed Lowicryl resin-embedded human kidneys of three patients with AA amyloidosis to investigate the association of various basement membrane components with amyloid fibrils. An immunogold technique was used and antibodies to serum amyloid A, heparan sulphate proteoglycan, type IV collagen, P component, and fibronectin were applied to human normal and amyloid glomeruli. The amyloid was identified as AA, and P component was shown to be intimately associated with the fibrils. In addition, heparan sulphate proteoglycan was associated with amyloid in all subendothelial, subepithelial and intramembranous glomerular basement membrane deposits, and those throughout the mesangial matrix. This contrasted with the distribution of the proteoglycan in the normal glomerulus where it was found predominantly on the epithelial aspect of the basement membrane and only in the more peripheral regions of the mesangium. The accumulation of heparan sulphate proteoglycan with amyloid resulted in a marked increase in its amount in the glomeruli. The amyloid deposits contained little or no type IV collagen or fibronectin. These findings demonstrate a strong association of heparan sulphate proteoglycan with amyloid and suggest different roles for the various glomerular basement membrane components in amyloidogenesis.     

Capillary filtration coefficient and urinary albumin leak at altitude

Rapid ascent to altitude risks the development of acute mountain sickness. This study demonstrates changes in peripheral capillary filtration coefficient and renal protein loss in subjects suffering from various degrees of mountain sickness after passive ascent to 4559 m. Capillary filtration coefficient of the calf capillary bed, measured by computer-based multistep strain gauge plethysmography, increased significantly after 23.5 h at altitude when symptoms were most severe: 4.45 (2.76–6.03) to 6.31 (3.86–11.07) ml min^–1 per 100 g of tissue mmHg^–1, median (range) (P <0.02). Urinary albumin excretion was increased after one night at altitude from 1.1 (0.6–1.5) to 2.45 (1.0–6.8) mg of albumin per mmol of creatinine (P <0.05). These results demonstrate simultaneous leakage of a peripheral capillary bed to fluid measured by strain gauge plethysmography, and renal albumin leak, and suggest a systemic process of increased capillary leakage for different-sized molecules caused by rapid exposure to hypobaric hypoxia.