Biomedical subjects
Publications and source records attributed to I Denfors.
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The effect of oral zinc supplementation in patients with cystic fibrosis (CF) was investigated in a placebo-controlled, double-blind, crossover study with each treatment period covering 6 months. CF patients (n = 13, aged 2 years, 3 months to 19 years, 1 month) started with placebo and after 6 months, they received zinc therapy. Another 13 patients (aged 3 years, 5 months to 16 years, 10 months) started in the reverse order. Before zinc supplementation, all CF patients had low plasma levels of zinc which normalized during treatment. This effect was, however, transient. CF patients also had low concentrations of plasma selenium. A small decrease in the number of leukocytes was also noted during zinc therapy. In response to zinc treatment, no changes in the clinical status of the patients were observed either by the investigators or by the patients. Growth velocity was the same during the placebo and zinc treatment periods. No significant changes in lung function occurred in response to either placebo or zinc. It appears that the observed low plasma zinc concentration in CF patients was due to an impaired zinc absorption from the gut which was counteracted by an increased supply of oral zinc. No beneficial effect from zinc supplementation on clinical status, growth velocity, or lung function was found in this study.
It has previously been demonstrated that patients with infantile autism demonstrate impaired in vivo platelet behaviour. Therefore, in 14 children (13 boys and 1 girl) with infantile autism (aged 2-14, mean 6 years) and 12 healthy control boys (aged 6-15, mean 11 years) we studied in vitro platelet reactivity using ADP- and collagen-induced platelet aggregation. In each child a total of 7 different final concentrations of ADP and 4 different concentrations of collagen were employed. At all concentrations of ADP and collagen used the autistic children consistently exhibited diminished platelet aggregability; the differences, however, did not reach statistical significance. Therefore a wider panel of in vitro tests is apparently required and a larger group of patients be studied to help elucidate the functional/metabolic platelet defect met in infantile autism.
The relationship between the splenic blood flow and the intrasplenic platelet kinetics on the one hand, i.e. the two factors which govern the size of the exchangeable splenic platelet pool, and the spleen size on the other were assessed in 21 patients afflicted with haematologic disorders and variable splenomegaly. The splenic blood flow and intrasplenic platelet kinetics were measured using 111In-labelled platelets and compartmental analysis of their equilibration between circulating blood and splenic pool; the spleen size was determined by scintigraphy using 99mTc-labelled stannous colloid. Significant correlations were recorded between the spleen size and the splenic platelet pool size (r = 0.76; P less than 0.001) and between the spleen size and the splenic blood flow (r = 0.56; P less than 0.01). Splenic perfusion decreased significantly with increasing spleen size, but there was no relationship between the spleen size and the intrasplenic platelet transit time. However, an association was present between splenic perfusion and intrasplenic platelet transit time (r = -0.44; P less than 0.05). It is concluded that the splenic blood flow is the major determinant of the size of the exchangeable splenic platelet pool in splenomegalic states, and that the determination of spleen size using 99mTc-scintigraphy gives a rough estimation of the pool size. Splenic perfusion appears to be one of the factors which determine the intrasplenic platelet transit time.
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