2ZD, 2Department of Biochemistry and 3Department of Pharmacology, Marischal College, University of Aberdeen AB9 lAS 1 The localisation and distribution of cytochrome P-450 in human tissues has been studied by immunocytochemistry using a monoclonal antibody to a major form of human hepatic cytochrome P-450, P-45OhA7, which is closely related to cytochromes P-450 HLp and P-45ONF. 2 Strong immunoreactivity was identified in hepatocytes, columnar absorptive epithelial cells of the small intestine, polymorphonuclear leucocytes and their precursors in the bone marrow, and in mast cells.3 Weak immunoreactivity was present in the proximal tubules of the kidney, pancreatic acini, gall bladder epithelium, squamous epithelium and sebaceous glands of the skin, interstitial cells of the testis and luteal cells of the ovary. 4 Immunoreactivity could not be demonstrated in the adrenal gland, placenta, colonic epithelium and alveolar type II cells and Clara cells of the lung.

SUMMARYTwo indices of motor unit recruitment, the ramp-force and repetitive-discharge thresholds, were compared in the first dorsal interosseus muscle of ten young and twelve elderly subjects. The purpose was to determine the effect of age on the relationship between the two recruitment thresholds and the spike-triggered average force of motor units. Each subject performed three tasks requiring isometric abduction of the left index finger: a maximum voluntary contraction (MVC), a ramp-and-hold contraction, and a repetitive-discharge task. The elderly subjects used coactivation of the antagonist muscle (second palmar interosseus) more frequently than the young subjects during the ramp-and-hold contraction. Many elderly subjects expressed difficulty with the controlled ramp-down phase of the ramp-and-hold contraction and preferred a coactivation strategy to a derecruitment strategy for this task. There were no differences due to age or gender in the ramp-force thresholds between the various groups. However, the normalized repetitivedischarge threshold was significantly less for the younger subjects and for the male subjects. Nonetheless, the two recruitment thresholds were able to predict the spike-triggered average force with similar success for both the young and the elderly subjects. These data suggest that the recruitment threshold of a motor unit in first dorsal interosseus was characterized equally well by either the ramp-force or repetitive-discharge measurement for both young and elderly subjects but that coactivation was used more frequently by the elderly subjects during the ramp-and-hold task.

Haemolytic uraemic syndrome secondary to infection with neuraminidase producing Streptococcus pneumoniae is well recognised, but was previously considered to be rare. This case report describes the course of a 9-month-old male with pneumococcal pneumonia, T activation and haemolytic uraemic syndrome. The clinical features of three other cases treated in Southeast Queensland in the past 2 years and 12 previously reported cases are summarised. The widespread availability of rapid diagnostic testing for this entity should allow for increased recognition, enabling appropriate use of low plasma volume blood products with improved patient outcome.

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