The role of the endothelium to influence smooth muscle contraction in normal and varicose veins was investigated in vitro using saphenous vein preparations obtained at vascular surgery. Paired control and endothelium-denuded rings were tested simultaneously and contracted with noradrenaline (10(-9)-10(-4) M). Identical experiments were also performed on sheep femoral veins and arteries. Noradrenaline induced maximal tension was 30% lower in varicose compared to normal veins. In normal veins removal of endothelium significantly reduced the maximal response to noradrenaline by 40% whereas in varicose veins no significant reduction could be seen. In the sheep femoral vein removal of the endothelium also resulted in decrease of noradrenaline-induced contraction. It can be concluded that in the human saphenous vein the endothelium has a contraction facilitating effect in response to stimulation with noradrenaline. In varicose veins the endothelial-mediated enhancement of noradrenaline-induced vasoconstriction is reduced probably because of endothelial damage. This observation may be of importance in the pathogenesis of varicose veins.

The adherence of two strains of Staphylococcus epidermidis to human fibrin-platelet clots in vitro was investigated. Both strains were noncapsulated, nonhemagglutinating, and nonslime producers. Binding was not related to surface charge, carbohydrate profile, or hydrophobicity of the bacteria. Adherence was reduced fourto sixfold (P < 0.001) on pretreatment of bacteria with lipase, while neuraminidase, trypsin, phospholipase C, and sodium periodate did not alter their binding. Pretreatment of bacteria with substances known to bind lipoteichoic acid (LTA), such as human albumin and anti-LTA antibodies, also resulted in a fourfold (P < 0.001) reduction in adherence. Prior incubation of clots with free LTA, but not with deacylated LTA, produced a fourfold (P < 0.001) decrease in the adherence of homologous and heterologous strains of S. epidermidis. A similar reduction was also observed when LTAs derived from Staphylococcus aureus and Streptococcus pyogenes were used. These data provide evidence that the lipid moiety of LTA has a central role in the adherence of S. epidermidis to fibrin-platelet clots in vitro.

No abstract

No abstract

Fungal endocarditis has emerged as an important complication of patients undergoing cardiovascular surgery. Our patient had no past history of cardiac surgery, intravenous drug abuse or immunosuppressive therapy. He had received broad-spectrum antibiotics for varying periods, which might have predisposed him to this infection. The diagnosis was based on the demonstration of hyaline, septate branched fungal elements in the infected valvular tissue and isolation of Aspergillus flavus in culture. The delay in establishing the ante-mortem diagnosis because of repeatedly negative blood cultures, presence of disseminated intravascular coagulopathy and rapidly deteriorating kidney function were the major factors contributing to his poor prognosis and death, despite surgical removal of infected valves and antifungal therapy. This is the first report of endocarditis due to A. flavus from the Middle East.