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Biomedical subjects

F Schneider

Publications and source records attributed to F Schneider.

At least 271 records · Page 15Linked to original sources
PubMed1987

Polyploidization of G2M phase cells separated from aerobically and anaerobically grown Ehrlich ascites tumor cells.

G2-enriched fractions of Ehrlich ascites tumor cells (up to 80%-85% G2 cells) separated from anaerobically and aerobically cultured asynchronous populations by centrifugal elutriation revealed the same growth characteristics after recultivation under standard conditions: a significant proportion of cells with increased DNA (DNA content greater than 4C) emerged. Interruption of DNA synthesis by deprivation of oxygen may account for polyploidization (over-replication) of DNA but other mechanisms must be taken into consideration.

Aerobiosis↗
PubMed1987

Cytokinetic studies on the switch from glucose to uridine metabolism, and vice versa, of Ehrlich ascites tumour cells in vitro.

Glucose is normally required as the energy source and for the proliferation of neoplastic cells. For Ehrlich ascites tumour cells, kept under glucose-free culture conditions, this requirement was alleviated by uridine, indicating that the supply of ribose is obligatory for sustaining growth capacity. In a 96-hr culture experiment with mouse-derived cells, the increase in cell number from cultures supplemented with 5 mM uridine was 50-70%, whilst lactate production was 5% that of controls. An increase in the number of multinucleate cells was observed from cell-smears; DNA histograms indicated the presence of cells with a DNA content higher than 4c and an increased portion of cells in G2 phase. For precise determination of changes in cell cycle distribution on transfer of cells from glucose-supplemented to glucose-free conditions, the progression of phase-accumulated cells (by centrifugal elutriation) was monitored by DNA distribution analysis; G2 cells continued the cycle at a rate comparable to controls but were delayed, in the following cycle, predominantly in S and G2 phases. This was also observed with G1 cells from a G1-accumulated fraction in the first cycle. The addition of glucose to cells kept for some hours in glucose-free, uridine-supplemented medium resulted in an immediate increase in mitotic index (amplification by the colcemid method). The results are interpreted and support our concept that the delivery of compounds, necessary for normal growth, i.e. hexoses for glycoproteins and glycolipids, are limited as a consequence of the 'metabolic channelling' of pentose from uridine in Ehrlich ascites tumour cells. Therefore, the constantly lowered growth-rate in uridine-supplemented cells observed with long-term culture experiments could reflect an adaptation of growth-cycle to these limitations.

Animals↗
PubMed1987

Inhibition of aminoacylase from hog kidney by 2-ethoxy-1-(ethoxycarbonyl)-1,2-dihydroquinoline.

Aminoacylase is inactivated by 2-ethoxy-1-(ethoxycarbonyl)-1,2-dihydroquinoline (EEDQ), a specific carboxyl reagent; inactivation is pH-dependent. The inhibition kinetics were of the first-order type. pH titration shows that half-maximal inactivation is obtained at pH 6.0 +/- 0.2, suggesting that the EEDQ reactive carboxyl group has a rather high pK value. Protection against EEDQ inactivation of the enzyme is afforded by competitive inhibitors, most effectively by tosyl-L-phenylalanine. These results suggest that a carboxyl group is located at or near the active site of the enzyme. A possible function of the carboxyl group in the catalytic process is proposed.

Amidohydrolases↗
PubMed1987

Pulmonary edema in renal transplant patients.

A syndrome heralded by fever, deterioration of graft function, respiratory failure accompanied by pulmonary infiltrates has been termed "transplant lung." We hemodynamically studied eight such patients. At the height of their illness, pulmonary artery wedge pressure (PAWP) was elevated to 19.3 +/- 2.6 mm Hg along with mean pulmonary artery pressure (PAP) of 35.0 +/- 3.8 mm Hg in presence of increased cardiac index (CI) of 4.9 +/- 0.9 L.m2.min. Pathophysiology of pulmonary edema appears to include high left ventricular filling pressures, pulmonary hypertension, alterations of oncotic hydrostatic gradient, and increased cardiac output. A partial reversal of pulmonary hypertension was observed with dialysis or diuresis. Our data suggest incipient renal failure and fluid accumulation as the etiology of hemodynamic pulmonary edema in "transplant lung."

Adult↗
PubMed1987

[Prognostic factors of decompensated chronic respiratory insufficiency. Apropos of a series of 272 cases].

Over a 6 years' period (1980-1986), 272 patients with chronic respiratory disease were admitted for respiratory failure to the same intensive care unit. The series was characterized by the high mean age of the patients (69.3 years) and by the high proportion of those who were ventilated (75%); 33.7% of the patients died within 1 month of discharge. The survival rate at 5 years estimated by the actuarial survival curve was 28%. Parameters measured during the acute decompensation phase were analyzed statistically. The main prognostic factors regarded as unfavourable were: old age and associated visceral failure particularly, important loss of weight and muscular atrophy, pre-existing neurological sequelae, left ventricular dysfunction, simplified Le Gall score above 15, presence of respiratory encephalopathy, stroke or viral infection as precipitating factors of decompensation, transfer from other hospital units after failure of medical treatment, and need for mechanical ventilation for more than 30 days.

Actuarial Analysis↗
PubMed1987

[Vital capacity restitution curve: prognostic value in chronic decompensated respiratory insufficiency].

From a series of 50 patients with acute decompensation of chronic obstructive lung disease (38 of whom were treated by mechanical ventilation), the authors demonstrate the prognostic value of an easily obtained parameter of respiratory function: the vital capacity restitution curve (VCRC). From daily measurements of vital capacity, beginning on the day of admission, a graph is constructed which shows an initial period of increase in the degree of restitution, followed by stabilization of the values. An analysis of the various parameters embodied in this graph provides information about the prognosis. Such graphs can be divided into 3 zones of prognostic value: a favourable zone, an intermediate zone (mediocre survival with or without mechanical ventilation) and an unfavourable zone (death during the acute phase). Although a favourable prognosis can be made after 4 days of observation and almost always by the 10th day, an unfavourable prognosis cannot be made before the 21st day.

Aged↗
PubMed1987

Cardiopulmonary complications after major surgery: a role for epidural analgesia?

Improvement in postoperative pulmonary mechanics with epidural analgesia has been described. Data on the hemodynamic effects of this technique are absent from the surgical literature. To provide such data we have evaluated two groups of patients undergoing aortic reconstruction: group I (n = 25), general anesthesia and group II (n = 6), general anesthesia with adjunctive epidural analgesia. The groups were comparable preoperatively as judged by the incidence of cardiac history, preoperative ejection fraction, and measured hemodynamic parameters. Postoperatively there were no significant differences in the pressure-related parameters; however, rate-related factors including heart rate and double product were significantly decreased in group II with no reduction in cardiac index. Postoperative increases in total body oxygen consumption were also markedly attenuated by epidural analgesia. Epidural analgesia reduces the hemodynamic demands on the heart after major surgery and is a useful adjunct, especially in patients with coronary artery disease.

Aged↗