Characteristics associated with occurrence of stroke in patients with infective endocarditis - a retrospective cohort study.

BACKGROUND: Stroke is a severe complication of infective endocarditis (IE), associated with high rates of mortality. Data on how IE patients with and without stroke differ may help to improve understanding contributing mechanisms. METHODS: All patients treated for IE between 2019 and 2021 with and without associated stroke were identified from the medical records of three academic tertiary care hospitals in Germany, all part of Charité - Universitätsmedizin Berlin, Germany. Multivariable logistic regression analyses were performed to identify variables associated with the occurrence of stroke. RESULTS: The study population consisted of 353 patients diagnosed with IE. Concomitant stroke occurred in 96/353 (27.2%) patients. Acute stroke was independently associated with co-occurring extracerebral arterial embolism [adjusted Odds ratio (aOR = 2.52; 95% confidence interval (CI) 1.35-4.71)], acute liver failure (aOR = 2.62; 95% CI 1.06-6.50), dental focus of infection (aOR = 3.14; 95% CI 1.21-8.12) and left-sided IE (aOR = 28.26; 95% CI 3.59-222.19). Stroke was found less often in IE patients with congenital heart disease (aOR = 0.20; 95% CI 0.04-0.99) and atypical pathogens isolated from blood culture (aOR = 0.31; 95% CI 0.14-0.72). CONCLUSIONS: Stroke is more likely to occur in individuals with systemic complications affecting other organs, too. Special attention should be addressed to dental status. The low incidence of stroke in patients with congenital heart disease may reflect awareness and prophylactic measures.

On the mechanism of glycolysis stimulation by neutral detergents in 3T3 and Ehrlich ascites tumor cells.

Glycolysis of 3T3 and Ehrlich ascites tumor cells was greatly enhanced by Nonidet P-40 or Triton X-100 at about 100 micrograms/mg cell protein. This enhanced glycolysis was partly sensitive to rutamycin and partly sensitive to ouabain, suggesting that the detergent released the control of the ATPase of the mitochondria and of the plasma membrane Na+K+-ATPase. Nonidet P-40 had no effect on glycolysis in cell-free extracts from Ehrlich ascites tumor cells to which soluble mitochondrial ATPase was added. Measuring ouabain-sensitive 22Na efflux and using ouabain-sensitive lactate production as a measure of ATP hydrolysis by the Na+K+ pump, it was shown that Nonidet P-40 greatly decreased the efficiency of the Na+K+ pump. Quercetin increased the efficiency of pumping in EAT cells both in the absence and presence of the detergent.

A placental polypeptide activator of a membranous protein kinase and its relation to histone 1.

Crude transforming growth factor preparations of placenta contain a polypeptide that is required for the activity of a protein kinase that has been purified from plasma membrane preparations of Ehrlich ascites tumor cells. The kinase activator has been separated from transforming growth factor beta by reversed-phase HPLC and affinity chromatography. Like the transforming growth factor, it is heat stable and trypsin labile, but it is not inactivated by dithiothreitol. In sodium dodecyl sulfate/polyacrylamide gel electrophoresis the purified preparation shows a major double band at about 31,000 daltons. Comparisons of electrophoretic mobility, protein kinase stimulatory activity, and cross-reactivity with an antibody against histone 1 suggest that the placental activator is identical with histone 1.

New protein kinase from plasma membrane of Ehrlich ascites tumor cells activated by natural polypeptides.

A polypeptide-dependent protein kinase was purified about 80-fold from an extract of plasma membranes of Ehrlich ascites tumor cells. The membranes were extracted with Nonidet P-40, and the extract was purified by ammonium sulfate fractionation and hydroxylapatite and affinity chromatography. The activity was stimulated 10-fold or more by polypeptide preparations from a variety of tissues, including placenta and hypothalamus. Polypeptide-dependent protein kinase had a pH optimum of about 7.5 and required Mg2+ for activity. Mn2+ at low concentrations (200 microM) stimulated enzyme activity somewhat but inhibited activity strongly at higher concentrations. The best available substrate for polypeptide-dependent protein kinase was beta-casein, and little or no phosphorylation was observed with alpha-casein, kappa-casein, phosvitin, alpha-lactalbumin, alpha-lactoglobulin, and histone. However, several endogenous substrates from plasma membranes of Ehrlich ascites tumor cells were phosphorylated. Polypeptide-dependent protein kinase activity was not inhibited by 10 mM N-ethylmaleimide, and this resistance was useful in differentiating this protein kinase from other protein kinases that were present in crude fractions and sensitive to the inhibitor.

Stimulation of glycolysis by placental polypeptides and inhibition by duramycin.

Placental polypeptides present in crude preparations of transforming growth factors stimulate glycolysis when added to quiescent 3T3 cells, normal rat kidney, and chick embryo fibroblasts. The stimulation was apparent over a time period of at least 90 min and was seen at glucose concentrations ranging from 1 to 30 mM. Duramycin, an antibiotic isolated from Streptomyces cinnamomeus, inhibits the polypeptide-stimulated and nonstimulated glycolysis of intact cells, since it permeabilizes cells to Pi and nucleotides. However, duramycin also inhibits the Na+-K+-ATPase as well as the ouabain-insensitive Mg2+-ATPase of plasma membranes. Duramycin has no effect on glycolysis catalyzed by cell-free extracts of Ehrlich ascites tumor cells in the presence of mitochondrial ATPase but partially inhibits glycolysis when ADP and Pi are generated by ATPases of plasma membrane preparations.