Delayed closure of ductus arteriosus in term newborns with congenital hypothyroidism: effect of L-thyroxine therapy.

Congenital hypothyroidism is associated with increased incidence of congenital defects (15.6%), frequently involving the heart (5.8%). Only few studies have evaluated the association between congenital hypothyroidism and patent ductus arteriosus. We report on two term newborns affected by thyroid agenesis and patent ductus arteriosus that closed after starting L-thyroxine substitutive therapy. This association suggests a close relation between hypothyroidism and patent ductus arteriosus. Hypothyroidism should be considered in term infants with patent ductus arteriosus because thyroid hormone production is among the prerequisites for postnatal ductal closure.

Lipid-lowering effect of carnitine in chronically uremic patients treated with maintenance hemodialysis.

Hypertriglyceridemia is often present in chronically uremic patients treated with maintenance hemodialysis and has been considered a risk factor in the accelerated development of atheroma. Muscle carnitine content is low in hemodialyzed patients. This abnormality may help to explain the myopathy and cardiomyopathy often observed in these subjects. In addition, carnitine might play a role in the hypertriglyceridemia in renal failure. Carnitine, which is necessary for fatty acid oxidation, has been recently reported to lower serum triglycerides in patients with type IV hyperlipoproteinemia. Carnitine was administered intravenously three times weekly at the end of hemodialysis in eight patients. Carnitine was given in 0.5 g doses for 8 weeks and then in 1.0 g doses for 6 additional weeks. There was a significant decrease in serum triglycerides at the end of treatment. In contrast, serum lipids in eight hemodialysis patients receiving placebo did not change significantly. Carnitine administration does not cause any side effect except some euphoria. These results suggest that carnitine may be effective in the treatment of hypertriglyceridemia in dialysis patients.

Morphological microcirculatory aspects in chronic uremia.

A fingertip biopsy was made in 18 patients affected by chronic uremia, in order to study the histangic changes. Partial occlusion of the blocking devices, capillary dilation and regressive changes in sensitive corpuscles, especially in Vater-Pacinian ones, were observed. The incidence of dermal necrosis and of calcium deposits was also high.

Acetate intolerance in chronic uremic patients.

The metabolic effects of an acute acetate load have been investigated in chronic uremic patients and in controls. The decay rate of blood acetate levels was significantly lower in patients than in controls. Higher levels of blood acetoacetate and 2-oxoglutarate and plasma triglycerides were observed in the patients after the load. No difference was detectable in plasma levels of unesterified fatty acids and cholesterol between the two groups of subjects. Acetate oxidation in citric acid cycle may be reduced in uremia owing to a lack of coenzyme A. These observations raise the possibility that chronic acetate administration with the dialysate induces hypertriglyceridemia and accelerates the development of atherosclerosis in hemodialysis patients.