Prophylactic resection of a tricuspid valve vegetation in infective endocarditis

A heroin addict who appeared to have recovered clinically from infective endocarditis of the tricuspid valve as judged by the usual criteria underwent prophylactic resection of a large vegetation on the tricuspid valve in order to prevent severe pulmonary embolism. Prophylactic surgery was justified by the size and as judged by cross-sectional echocardiography of the vegetation and its morphology.     

Partial splenectomy in Gaucher's disease

In 11 children with hypersplenism due to Gaucher's disease, partial splenectomy was planned with the aim to prevent the development of postsplenectomy sepsis and also to slow the advance of the disease in the rest of the reticuloendothelial system by permitting continuing accumulation of the beta-glucocerebroside in the remaining splenic tissue. In seven children, partial splenectomy was performed successfully, the weight of the splenic tissue removed ranging from 400 to 3,680 g. The postoperative course was uneventful and the average duration of hospitalization was 12 days. In subsequent follow-up, isotope scanning demonstrated continuing growth of the splenic remnant and there were no episodes of postsplenectomy sepsis nor evidence of increased accumulation of beta-glucocerebroside in the liver or bones. These children showed a marked improvement in the growth curve and dramatic improvement in the hematologic picture. Of the four remaining children, in two, partial splenectomy was followed by complete removal of the remaining spleen due to necrosis, whereas in two, total splenectomy was performed since the huge spleens were extensively infarcted. Our experience suggests that partial splenectomy is the treatment of choice in the management of young patients with hypersplenism due to Gaucher's disease.     

Caisson disease of bone

Caisson disease of bone, which may affect compressed air workers and divers, is characterized by regions of bone and marrow necrosis that may lead to secondary osteoarthrosis of the hip and shoulder joints. A review of the pathologic, radiologic, and clinical aspects demonstrated uncertainties in the exact etiology. Early diagnosis is often not possible because of the delayed appearance of radiologic abnormalities. Research into these two aspects of this condition was carried out by the Medical Research Council Decompression Sickness Research Team in Newcastle upon Tyne over a ten-year period (1972 to 1982). Because no suitable animal model exists for the study of this condition, bone and marrow necrosis was produced by embolism of bone blood vessels with glass microspheres. With this model, it was shown that the presence of bone and marrow necrosis could be detected by bone scintigraphy using 99mTc-MDP and by measuring changes in serum ferritin concentration at a much earlier stage than was possible by radiography. However, only the former method has proved useful in clinical practice. Investigations into the etiology of caisson disease of bone have shown evidence for an increase in marrow fat cell size resulting from hyperoxia. This phenomenon may play a role in the production and localization of gas bubble emboli, which are thought to be the cause of the bone and marrow necrosis.     

Vitamin D3 derivatives inhibit the differentiation of Friend erythroleukemia cells

A number of vitamin D3 metabolites inhibit benzodiazepine- and dimethyl sulfoxide-induced differentiation of Friend erythroleukemia cells. The inhibition is dose dependent and occurs at nM concentrations. The order of potency of these compounds is 1,25-dihydroxycholecalciferol greater than 1,25,26-trihydroxycholecalciferol greater than 1,24R,25-trihydroxycholecalciferol greater than 1 alpha-hydroxycholecalciferol greater than 24R,25-dihydroxycholecalciferol greater than 25S,26-dihydroxycholecalciferol. The inhibition is maximal when the vitamin D3 analogs are added together with the inducer, and becomes progressively decreased with delayed addition. These results suggest that the vitamin D3 metabolites may play a regulatory role in erythropoiesis.