Wiener klinische Wochenschrift
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Wien. Klin. Wochenschr. · Jan 2007
Synergistic interaction between atovaquone and retinol in Plasmodium falciparum in vitro.
The study has been conducted with the objective of assessing the blood schizontocidal activities of atovaquone (ATO), retinol (RET) and combinations of both (ATO-RET) at set retinol concentrations corresponding to the 50th, 65th and 80th percentile of the physiological serum retinol levels. The in vitro tests followed the WHO standard protocol Mark II for measuring the inhibition of schizont maturation in Plasmodium falciparum. ⋯ The geometric mean cut-off concentrations of schizont maturation of atovaquone alone and for atovaquone in ATO-RET low, medium and high were 282.5 nM, 79.0 nM, 38.7 nM and 23.7 nM, respectively. These results and those of the Berenbaum analysis based on the fractional inhibitory concentrations indicate synergistic pharmacodynamic interaction between atovaquone and retinol, a phenomenon suggesting that the antimalarial activity of atovaquone could be enhanced by supplementation with retinol.
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Gastrinomas are functional neuroendocrine tumors of the gastroenteropancreatic system. Surgery is first line treatment in gastrinomas, however often fails to be curative. This manuscript reviews current strategies of medical treatment of surgically non-curable gastrinoma. ⋯ In well differentiated neuroendocrine carcinoma (G1 and G2) a so-called biotherapy with somatostatin analogues exists as first-line and chemotherapy with streptocotozin plus doxorubicine/5-FU as second-line medical treatment option. In poorly differentiated neuroendocrine carcinoma (G3) chemotherapy with etoposide plus cisplatin is possible. Prospective future therapeutic strategies may include treatment with novel somatostatin analogues as well as angiogenesis inhibitors and kinase inhibitors targeting tumor-specific signaling cascades.
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The most frequent conditions of hypergastrinemia in man are the Zollinger-Ellison syndrome with autonomous gastrin hypersecretion by the tumour cell and reactive hypergastrinemia in type A autoimmune chronic atrophic gastritis with achlorhydria causing unrestrained gastrin release from the gastrin-producing antral G-cells. Both entities differ with respect to the pH in the gastric fluid, which is < 2 in patients with Zollinger-Ellison syndrome and neutral in type A gastritis. Other conditions with moderate hypergastrinemia as treatment with proton pump inhibitors, gastric outlet obstruction, previous vagotomy, chronic renal failure or short bowel syndrome are of minor clinical importance.
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In addition to paCO(2), Stewart's acid base model takes into account the influence of albumin, inorganic phosphate, electrolytes and lactate on acid-base equilibrium. It allows a comprehensive and quantitative analysis of acid-base disorders. ⋯ Stewart's approach is therefore a valuable tool in addition to the customary acid-base approach based on bicarbonate or base excess. However, some chemical aspects of Stewart's approach remain controversial.