Biomedical subjects
Publications and source records attributed to J Boyer.
We report a case of a male patient suffering from a severe hemorrhagic radiation proctitis which gradually ceased with hyperbaric oxygen. We discuss the mechanisms of chronic radiation injury and the effect of the hyperbaric oxygen. This therapy is proposed as an alternative to surgical intervention for this abnormality.
A single intraperitoneal injection of ethanol (4 g/kg) in rats elicited a bimodal response of acylation rates in phosphatidylcholine and phosphatidylethanolamine of intact red blood cells. Within an initial period, ethanol inhibited acylation rates. The inhibition then reversed, leading to increased values which persisted as long as ethanol was present in plasma. Acylation rates were not correlated to ethanol concentrations in plasma. We suggest that red cells first desensitize to, then overcompensate for the inhibitory effect of ethanol on acylation reactions. These adaptive changes may be one of the events mediating membrane tolerance to ethanol.
We conducted a prospective randomized controlled study to evaluate the effectiveness of propranolol and sclerotherapy, compared to a control group, in the prevention of variceal rebleeding in alcoholic cirrhotic patients. Among the 79 patients included, the distribution of patients according to Child-Pugh classification was: A, 22%; B, 40%; and C, 38%. Propranolol was given twice daily with a mean final dose of 54 +/- 16 mg/day, this resulted in a mean reduction in resting heart rate of 26 +/- 7%. Sclerotherapy was performed weekly using 1% polidocanol. End points were rebleeding or death. During the mean follow up of 19 +/- 16 months, 43 patients bled and 22 patients died. The cumulative percentages of patients free of rebleeding at 1 year were: propranolol, 81% (95% confidence interval (CI): 63-92); sclerotherapy, 64% (95% CI: 45-82); control, 54% (95% CI: 36-71); these differences did not reach statistical significance. The cumulative percentages of patients alive at 1 year were: propranolol, 92% (95% CI: 76-98); sclerotherapy, 79% (95% CI: 58-91); control, 81% (95% CI: 60-93); these differences were not statistically significant. Alcohol withdrawal, which occurred in 66% of patients, was an independent predictive factor associated with a decreased risk of rebleeding or death. In conclusion, a life table analysis of patients free of rebleeding, as well as of patients surviving, revealed a tendency in favour of propranolol. The lack of a statistical support for these two favorable effects could be due to poor statistical power.(ABSTRACT TRUNCATED AT 250 WORDS)
Challenging intact erythrocytes from naive rats with ethanol resulted in dose-dependent decreases in rates of acylation of phosphatidylcholine and phosphatidylethanolamine. In erythrocytes from ethanol-treated animals, the responses were of lesser magnitude, indicating a lower sensitivity to ethanol. This relative resistance, typical of the state of tolerance, was not associated with increased baseline rates of acylation of PC and PE, nor with changes in fatty acid specificity of acylation reactions. Taken together, the data suggest that (1) intact rat erythrocytes represent a reliable and easily reproducible model for studying biochemical correlates of the adaptive response to ethanol; (2) phospholipid acylation reactions are implicated in the initial sensitivity and subsequent acquisition of tolerance to ethanol in membrane erythrocytes; (3) on the basis of the measured acylation reactions, rat erythrocytes appear to develop tolerance, but not dependence, to ethanol.
1. Triacylglycerol in erythrocytes from normal human subjects was estimated to average 2.7 +/- 0.7 nmol/10(10) cells, equivalent to 0.07% of total lipids or 0.3% of neutral lipids. 2. The specific activity of triacylglycerol labelling attained by incubating intact erythrocytes with [3H]oleic acid was 10 nmol/mumol, a value 20-fold higher than that of the highest labelled phospholipid, sphingomyelin; as isolated by ultracentrifugation over a density gradient, the youngest erythrocytes exhibited a labelling rate 10-fold higher than that of older cells. 3. The triacylglycerol content was not modified in erythrocytes from chronic alcoholics, whereas the mean rate of triacylglycerol labelling was 31% (P less than 0.05) higher than that of control subjects, and did not normalize 4 weeks after alcohol withdrawal. 4. These results indicate that triacylglycerol, although a quantitatively minor component, is one of the most active metabolites in the lipid matrix of the human erythrocyte membrane and appears to be implicated in the membrane response to antagonistic agents.
The aim of the present study is to assess the frequency of pancreas divisum and the features of patients with pancreas divisum in order to assess the role of this anomaly in the occurrence of pancreatitis. A total of 1049 endoscopic retrograde pancreatographies were studied between 1978 and 1988. Patients with pancreas divisum were studied in terms of their clinical findings and their disease (pancreatitis or not). Pancreas divisum was diagnosed in 62 patients (5.9%). No statistical differences with regard to age and sex were found between patients with and without pancreas divisum. The frequency of pancreas divisum was similar in the different groups of disease, especially chronic pancreatitis, acute pancreatitis, recurrent pancreatitis and idiopathic pancreatitis. The study of pancreatograms showed that dorsal ductal abnormalities alone were found as frequently as ventral alterations alone. Our results show that pancreas divisum cannot be directly implicated in the occurrence of pancreatitis, and should not prompt a systematic sphincterotomy of the accessory papilla. This treatment should only be considered in the rare cases of acute recurrent idiopathic pancreatitis with dorsal ductal dilatation and stenosis of the accessory papilla.
Challenging intact erythrocytes from normal human subjects with ethanol resulted in dose-dependent decreases in rates of acylation of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) while triacylglycerol (TAG) acylation was stimulated. In erythrocytes from alcoholic subjects, the responses were of lesser magnitude, indicating a lower sensitivity to ethanol. This in vitro resistance, typical of the state of tolerance, was associated in erythrocytes from alcoholic subjects with increased baseline rates of acylation of PC, PE and TAG, suggesting high levels of glycerolipid fatty acid turnover. These results suggest that (1) intact human erythrocytes are qualitatively and quantitatively valid for studying the adaptive response to ethanol; and (2) chronic alcoholism is associated with increases in turnover rates of the acyl moieties of lipid membrane components regardless of the pattern of initial sensitivity to ethanol. Increased acylation rates during chronic alcoholism might modify the remodeling of the lipid matrix and thereby the membrane function.
We have investigated the patterns of incorporation of stearic, oleic, and linoleic acids into phosphatidylcholine (PC) and phosphatidylethanolamine (PE) of intact red blood cells of differing age isolated by centrifugation on discontinuous density gradient. Acylation rates of PC and PE elicited marked declines from the reticulocyte to the young erythrocyte stage followed by minimal changes of acylating potency in older cells; this biphasic decay pattern was similar with the three fatty acids. Molar acylation rates were higher for PC than for PE in reticulocytes, whereas they were comparable in erythrocytes. PC served as preferred fatty acid acceptor in circulating red blood cells, a function which was largely accounted for by PC contained in the small percentage of circulating reticulocytes. On a per cell basis, this function of PC was due to the cumulative effects of higher molar acylation rates in reticulocytes and higher content in PC over PE in the red blood cell membrane. Acylation rates in PC and PE increased with the number of unsaturated bonds in the acylating fatty acid, regardless of cell age.
Ethinyl estradiol administered in vivo to female rats resulted in a mild anemia with a 120% increase in reticulocytosis. Consistent with a previous study, the red blood cell cholesterol-to-phospholipid molar ratio was decreased by 25%, whereas fatty acyl incorporation was significantly increased into phosphatidylethanolamine (PE) and not into phosphatidylcholine (PC), the major acyl acceptor in red blood cells. Analysis of this estrogen-dependent acylation increase as a function of cell age indicated that it was not expressed in reticulocytes but in erythrocytes and was associated with cell aging. Estrogen was further shown to increase the red blood cell susceptibility to peroxidation generated by incubation with H2O2. Altogether, the results suggest that estrogen indirectly increases phospholipid acylation in red blood cells by decreasing protection against oxidative damage, thereby favoring the action of endogenous phospholipases against oxidized substrates. This occurs predominantly in PE of oldest cells because 1) PE, being more unsaturated than PC, is more sensitive to oxidation, and 2) susceptibility to oxidation increases with cell age.
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We report a case of a patient presenting with a small cell cancer of the lung which was limited to the thorax and treated by radiotherapy and chemotherapy in March 1983. In december 1986 a contralateral small cell cancer still limited to the thorax was discovered and treated with success using chemotherapy. Nevertheless the complete remission obtained did not last beyond 16 months and the patient died in september 1988. We discuss the possibility of late metastasis but we think the occurrence of a second small cell cancer is the more plausible hypothesis.
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Explore the source record for details and available documents.