Cleveland clinic CorAide blood pump circulatory support without anticoagulation

The Cleveland Clinic CorAide left ventricular assist system consists of a permanently implantable centrifugal pump in which the rotating assembly is completely suspended and noncontacting. A series of chronic animal in vivo studies were conducted to evaluate the biologic effects of CorAide circulatory support without the use of anticoagulation therapy. The CorAide pump was implanted in six calves (five calves for 21 to 32 days and one calf for 95 days). The first five calves received intravenous heparin during the early postoperative periods (2-7 days). Heparin administration was then discontinued and no other anticoagulant drugs were used for the duration of the experiments. The last calf did not receive any anticoagulant except for a bolus dose of heparin (200 U/kg) during surgery. Hemodynamics were stable in all six calves, with a mean pump flow of 5.6+/-1.2 L/min and mean arterial pressure of 100+/-4 mm Hg. The blood pump surfaces were clean of thrombus in all six calves. Significant findings at autopsy were limited to one case of renal infarction. There was no incidence of mechanical failure, bleeding, or device infection. The CorAide pump can be safely run with minimal or no anticoagulant therapy.     

Role of cell signaling systems in the regulation of Ca2+-activated potassium channels in erythrocytes

The effect of inhibitors of calmodulin and protein kinase C, complex [AlF₄]⁻, and potassium channel blockers on the parameters of calcium-induced hyperpolarization in human erythrocytes is studied by recording proton distribution between the cytoplasm and incubation medium in the presence of a protonophore. It is shown that the calmodulin inhibitor dis-C₃-5, the protein kinase C inhibitor staurosporine, and the blocker of highconductance calcium-activated potassium channels considerably suppress the calciuminduced hyperpolarization in erythrocytes. High concentration of [AlF₄]⁻ in the incubation medium inhibits hyperpolarization. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 123, No. 6, pp. 653–655, June, 1997     

The biochemical mechanisms of the toxic effects of some pyridine derivatives. 1. Study on the deamination of biogenic amines and other nitrogenous compounds in paraquat intoxication

Lethal intoxication of rats with the herbicide paraquat (1,1-dimethyl-4,4-bipyridilium dichloride) caused a stimulation of lipid peroxidation (LPO) in lung, brain, heart, liver, and kidney. Treatment of animals with antioxidant diludin (2,6-dimethyl-3,5-diethoxycarbonyl-1,4-dihydropyridine) or with the reductants sodium ascorbate or thiosulphate normalized the rate of LPO in these tissues and decreased mortality of intoxicated rats.The development of lethal paraquat intoxication was accompanied by a decrease of the deamination of monoamine oxidase (MAO) substrates serotonin, tryptamine, benzylamine, and tyramine in mitochondria of organs studied with simultaneous stimulation or appearance of deamination of glucosamine, -aminobutyric acid (GABA), putrescine, and L-lysine. The alterations in deamination of the nitrogenous compounds caused by paraquat were also reversed by treatment of animals with antioxidant or reductants.The data obtained support a hypothesis of an involvement of modification in catalytic properties of MAOs in the pathogenesis of paraquat intoxication.     

Hepatitis and cholestasis in infancy: clinical and nutritional aspects

A major complication of cholestasis is fat malabsorption related to decreased intestinal bile acids, which leads to malnutrition and fat-soluble vitamin deficiency. The impaired excretion of bile acids leads to a low intraluminal micellar concentration that causes long-chain triglyceride lipolysis and absorption to be ineffective. Medium-chain triglycerides (MCTs) are more readily absorbed when there are low concentrations of bile acids and therefore are a good source of fat calories; MCTs can be administered as MCT-containing formulas. In those children who are unable to take sufficient calories by mouth, it is important to start nocturnal enteral feeding to improve nutritional status. In infants with cholestasis, the absorption of fat-soluble vitamins (A, D, E and K) that require bile acids is also impaired, and supplementation is mandatory. Vitamin K deficiency may be responsible for hypoprothrombinaemia, which may lead to bleeding diathesis, Vitamin K (phytomenadione) should therefore be promptly administered intravenously, at a dose of 1 mg. Chronic vitamin E (α-tocopherol) deficiency is associated with a progressive neuromuscular syndrome that can cause cerebellar ataxia, areflexia and peripheral neuropathy. Supplements are given orally in doses of 3–5 times the normal requirement if cholestasis is incomplete. In complete cholestasis, supplements must be given intramuscularly at monthly intervals. In infants who fail to thrive, dietary supplements of carbohydrate polymers and MCTs are required.     

Soy-based formulas and phyto-oestrogens: a safety profile

Phyto-oestrogens are non-steroidal plant-derived compounds that possess oestrogenic activity and act as selective oestrogen receptor modulators (SERMs). Among the dietary oestrogens, the isoflavone class enjoy a wide-spread distribution in most of the members of the Leguminosae family, including such prominent high-content representatives as soybean. Phyto-oestrogen research has grown rapidly in recent years owing to epidemiological studies suggesting that diets rich in soy may be associated with potential health benefits. There is a paucity of data on endocrine effects of soy phytochemicals during infancy, the most sensitive period of life for the induction of toxicity. The safety of isoflavones in infant formulas has been questioned recently owing to reports of possible hormonal effects. Infants fed soy formula receive high levels of phyto-oestrogens in the form of isoflavones (genistein, daidzein and their glycosides). To date, no adverse effects of short- or long-term use of soy proteins have been observed in humans and exposure to soy-based infant formulas does not appear to lead to different reproductive outcomes than exposure to cow milk formulas. Soy formula seems to be a safe feeding option for most infants. Nevertheless, much closer studies in experimental animals and human populations exposed to phyto-oestrogen-containing products, and particularly soy-based infant formulas, are necessary.