Influence of diabetic treatment regimens on vitamin D metabolism in elderly patients.

The influence of diabetic treatment regimens on vitamin D metabolism and on bone mineral content has been explored in 41 elderly patients with normal renal and hepatic functions. The data obtained suggest that oral treatment with hypoglycemic compounds exerts a negative influence on vitamin D metabolism. It is possible that the reduction of 25-OH-hydroxy-vitamin D levels depends on a high conversion rate to the active 1,25-dihydroxy-vitamin D, as a consequence of parathormone-stimulated increase of 1-alpha-hydroxylase activity. On the other hand, no differences in bone mineral densities were observed in correlation with the diabetic treatment regimens. Therefore, oral treatment with hypoglycemic compounds can only be associated with an accelerated vitamin D metabolism.

Idiopathic haemochromatosis and HLA antigens in Italy: is A3 Bw35 HLA haplotype a marker for idiopathic haemochromatosis gene in north east regions?

Thirty two unrelated Italian subjects with idiopathic haemochromatosis were studied. HLA-A3 was present in 26 of them (81% v 22% in controls; p less than 0.001) and HLA B7 in eight (28% v 9%; p less than 0.01). There was no important association between idiopathic haemochromatosis and HLA B14. Subdividing the patients on the basis of their regional origin a noticeably higher prevalence of HLA Bw35 in patients with idiopathic haemochromatosis from north eastern Italy was found than in those from Lombardy, or in the controls; there were no differences in the incidence of HLA A3 and B7 between patients with idiopathic haemochromatosis from different areas. A high prevalence of A3, Bw35, and A3, B7 haplotypes was found in our patients with idiopathic haemochromatosis. A3, Bw35 could be the haplotype most commonly linked to the idiopathic haemochromatosis gene in north eastern Italy.

Iron overload in subjects with beta-thalassaemia trait: role of idiopathic haemochromatosis gene.

We have characterized HLA antigens in subjects with beta-thalassaemia trait with and without iron overload. 50% of the cases with iron overload (v 18% of those without iron overload, P less than 0.01) are carriers of HLA-A3, the HLA antigen tightly linked to the IH allele. Thus, in a considerable number of these subjects, beta-thalassaemia and IH coexist. This association exerts a synergistic effect in inducing iron overload.

Erythrocyte ferritin in thalassemia syndromes.

Basic ferritin (liver-type) was measured in erythrocytes of subjects with alpha- and beta-thalassemia trait, thalassemia intermedia and Cooley's disease, and compared with normals and patients with abnormal iron metabolism without erythrocyte metabolic defect (iron deficiency anemia and idiopathic hemochromatosis). In all the thalassemic syndromes considered, erythrocyte ferritin was significantly higher than in normals (p less than 0.001) and increased progressively with the increasing 'severity' of the thalassemic disorder. In both thalassemic and non-thalassemic subjects, erythrocyte ferritin levels were related to body iron status, but in the thalassemic group, the increased erythrocyte ferritin values seemed also to be closely related to the intracellular metabolic abnormality. The severity of the defect in globin chain synthesis seemed to play an important role in determining ferritin accumulation in red cells of thalassemic subjects.

Early iron overload in beta-thalassaemia major: when to start chelation therapy?

Twenty-eight children with beta-thalassaemia major aged between 11 and 48 months were given intensive transfusions. Serum iron, transferrin saturation, serum ferritin, non-transferrin iron, and subcutaneous desferrioxamine-induced urinary iron excretion were measured. The results showed that even children with a limited number of transfusions had severe iron overload as indicated, in particular, by the raised serum ferritin levels and the high excretion rates after subcutaneous infusion of desferrioxamine. The desferrioxamine test was useful, even in very young children, in assessing response to chelation therapy thus enabling such treatment to be started early to prevent harm from iron overload.

The iron status of Italian subjects with beta-thalassemia trait.

Serum iron, transferrin saturation, serum ferritin and urinary iron excretion have been tested in a group of Italian subjects with beta-thalassemia trait. A number of these subjects, mostly men, had signs of increased iron load. Serum ferritin was the most sensitive index among those measured for detection of iron overload and was positively correlated with desferrioxamine-induced urinary iron excretion. Italian males with beta-thalassemia trait may be at high risk of developing iron overload even without prolonged iron or transfusional therapy.