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Biomedical subjects

P Bouchard

Publications and source records attributed to P Bouchard.

At least 199 records · Page 11Linked to original sources
PubMed1980

The localization of protein carboxyl-methylase in sperm tails.

Protein carboxyl-methylase (PCM), an enzyme known to be involved in exocytotic secretion and chemotaxis, has been studied in rat and rabbit spermatozoa. PCM activity and its substrate methyl acceptor protein(s) (MAP) were demonstrated in the supernate after solubilization of the sperm cell membrane by detergent (Triton X-100). A protein methylesterase that hydrolyzes methyl ester bonds created by PCM was demonstrated in rabbit but not in rat spermatozoa. This enzyme was not solubilized by nonionic detergent. The specific activities of PCM in rat spermatozoa from caput and cauda epididymis were similar and lower than that found in testis. By contrast, MAP substrates were low in testis and increased in parallel with sperm maturation in the epididymis. Multiple MAP were demonstrated in spermatozoa by polyacrylamide gel electrophoresis. The pattern of these proteins was similar in spermatozoa from different portions of the reproductive tract. Fractionation of heads and tails of rat spermatozoa on sucrose gradients indicated that PCM was found exclusively in the tail fraction, whereas MAP was detected both in head and tail fractions. The presence of all the components of the protein carboxyl-methylation system in spermatozoa and the localization of PCM and some of its substrates in the sperm tail are consistent with their involvement in sperm cell motility.

Animals↗
PubMed1980

Plasma vitamin D metabolites in a patient with sporadic hypophosphataemic osteomalacia (adult-onset type).

Sporadic hypophosphataemic osteomalacia (adult-onset type) was demonstrated in a 40-year-old man on the basis of severe osteomalacia, hypophosphataemia, hyperphosphaturia and glycinuria. Plasma immunoreactive parathyroid hormone (iPTH) concentration was 9.3 ng prot./ml (normal range: 4-8 ng prot./ml). Plasma 25-hydroxy-vitamin D and 24,25-dihydroxy-vitamin D concentrations were 11 and 2.4 ng/ml respectively. Basal 1 alpha,25-dihydroxy-vitamin D concentrations were slightly elevated (116 and 96 pg/ml) and increased to 240 pg/ml after 3 days on a low-phosphorus diet. The patient was put on oral treatment with 25-hydroxycholecalciferol (100 microgram per day) and phosphorus (1500 mg per day). On the 4th month on treatment, a clinical improvement was apparent. Plasma 25(OH)D was 44 ng/ml, plasma 1,25(OH)2D was 256 pg/ml. However, plasma phosphorus remained low (0.77 mmol/l). On the 9th month of treatment a radiological improvement was evident despite a persistent hypophosphataemia (0.68 mmol/l). These facts suggest in our patient the existence of a vitamin D-independent renal phosphorus leak.

Adult↗
PubMed1979

[Deviation in cortisol metabolism induced by rifampicin. Therapeutic consequences in adrenal failure (author's transl)].

Deviation of cortisol metabolism in favour of its 6 beta-hydroxylated derivative was demonstrated in two patients with adrenal failure receiving substitution corticosteroid therapy and rifampicin. The existence of a frank increase in the metabolic clearance antipyrin was in favour of an hepatic enzyme induction. After rifampicin treatment was stopped, the 24 hour urinary excretion of 6 beta-OH-F returned to normal, demonstrating the responsability of the drug. This enzyme induction results in a need to increase the dose of hydrocortisone substitution therapy in patients with Addison's disease treated with rifampicin.

Addison Disease↗
PubMed1979

Treatment of Cushing's disease by O,p'DDD. Survey of 62 cases.

In a study of nonsurgical therapy of Cushing's disease, 62 patients received O,p'-dichlorodiphenyldichloroethane (O,p'DDD), 16 of whom also received cobalt irradiation of the pituitary. After an initial treatment period averaging eight months, a remission of the disease was obtained in 38 of the 46 patients given O,p'DDD alone and in all patients who received drug combined with radiation. Although 60 per cent of these patients subsequently relapsed, additional courses of drug or radiation therapy were usually effective, and 63 per cent of the entire group of patients have so far been kept under control without adrenalectomy. (Forty patients have been followed for at least two years after the initial course of treatment.). O,p'DDD produced little gastrointestinal discomfort; an increased serum cholesterol was the main side effect. This drug allows long-term medical management of Cushings disease in most cases. Whether the combination of O'p'DDD with pituitary radiation is the best therapy has not been established.

17-Hydroxycorticosteroids↗
PubMed1978

[Tiapride in anesthesiology].

The psycho-motor sedative action of tiapride, which has been demonstrated in internal medicine, was studied in anesthesiology. A group of 253 patients hospitalized for urological (203 cases) or gynaecological (50 cases) operations were given standard premedication together with 100 to 300 mg of tiapride. Preoperative sedation and reduction of anxiety was excellent in 138 cases, moderate in 97 cases, and nil in 18 cases, under the influence of tiapride. Tiapride was perfectly well tolerated even in patients with debility, obesity, alcoholism and cardiac or respiratory insufficiency.

Adolescent↗
PubMed1976

Chemical modification of the tryptophan residues of wheat-germ agglutinin. Effect on fluorescence and saccharide-binding properties.

The oxidation of the tryptophan residues of wheat germ agglutinin by N-bromosuccinimide was investigated under non-denaturing and denaturing conditions. All three tryptophan residues present in wheat germ agglutinin subunit (molecular weight 18 000) could be modified in 0.1 M acetic acid/8 M urea, pH 3.9. One of the residues failed, however, to react with N-bromosuccinimide when the modification was in 0.1 M citrate buffer, pH 6.0. Tryptophan fluorescence of the protein was quenched concomitantly with the oxidation of two tryptophan residues even when the modification was carried out in acetic acid urea. After oxidation of two tryptophan residues per subunit of wheat germ agglutinin, only 15% of the original tryptophan fluorescence remained; upon excitation at 280 nm, tyrosine fluorescence centered at 305 nm could be resolved. The results suggest that there are only two emitters in the protein and that the third tryptophan residue is buried in the native protein and can be modified only in acetic acid urea. This tryptophan residue is quenched in the native protein. Saturation of wheat germ agglutinin with tri-N-acetylchitotriose did not protect the tryptophan residues from oxidation by N-bromosuccinimide. Under these conditions, however, the reactivity of the tryptophan residues towards N-bromosuccinimide was reduced and a higher concentration of the reagent was required to achieve the same extent of oxidation as in the absence of the saccharide. Oxidation of one tryptophan residue per subunit in acetic acid urea led to almost complete loss (97%) of hemagglutinating activity, a 3.5-fold decrease in the affinity constant for tri-N-acetylchitotriose and loss of ability of the subunits (SO20,w = 2.0 S) to reassociate to the native dimer (So20,w = 3.5 S) after dialysis against a non-denaturing buffer. No significant changes in the circular dichroism spectrum of wheat germ agglutinin were observed after oxidation of the three tryptophan residues, suggesting that no gross conformational changes occurred. The steric relationships between the fluorescent tryptophan residues of wheat germ agglutinin and saccharides are discussed.

Binding Sites↗
PubMed1976

An improved method for purification of wheat germ agglutinin (lectin) by affinity chromatography.

A simple purification of wheat germ agglutinin from commercial wheat germ is described. From defatted ground wheat germ, the lectin was extracted and then purified in a single step by filtration on an ion exchange chromatography column and adsorption on an insolubilized N-acetyl glucosamine derivative. The amount of lectin obtained from 1,000 g of wheat germ was larger than 500 mg. Although the yield was at least twice higher than that obtained with other methods, no impurities could be detected, and molecular characteristics are in good agreement with the protein purified by more sophisticated procedures.

Amino Acids↗
PubMed1967

Fatty acid changes in liver and plasma lipid fractions after safflower oil was fed to rats deficient in essential fatty acids.

1. Fatty acid patterns of liver and plasma triglycerides, phospholipids and cholesteryl esters were determined at intervals during 24hr. after essential fatty acid-deficient rats were given one feeding of linoleate (as safflower oil). 2. Liver triglyceride, phospholipid and cholesteryl ester fatty acid compositions did not change up to 7hr. after feeding. Between 7 and 10hr., linoleic acid began to increase in all fractions, but arachidonic acid did not begin to rise in the phospholipid until 14-19hr. after feeding. 3. Oleic acid and eicosatrienoic acid in liver phospholipid began to decline at about the time that linoleic acid increased, i.e. about 9hr. before arachidonic acid began to increase. 4. Changes in linoleic acid, arachidonic acid and eicosatrienoic acid in phosphatidylcholine resembled those of the total phospholipid. Phosphatidylethanolamine had a higher percentage content of arachidonic acid before the linoleate was given than did phosphatidylcholine, and after the linoleate was given the fatty acid composition of this fraction was little changed. 5. The behaviour of the plasma lipid fatty acids was similar to that of the liver lipids, with changes in linoleic acid, eicosatrienoic acid and arachidonic acid appearing at the same times as they occurred in the liver. 6. The results indicated that linoleic acid was preferentially incorporated into the liver phospholipid at the expense of eicosatrienoic acid and oleic acid. The decline in these fatty acids apparently resulted from their competition with linoleic acid for available sites in the phospholipids rather than from any direct replacement by arachidonic acid.

Animals↗