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Biomedical subjects

M Dumont

Publications and source records attributed to M Dumont.

At least 163 records · Page 9Linked to original sources
PubMed1988

Sensitive method of detection, quantitation and purification of peptides using pre-column derivatization with phenyl isothiocyanate.

A sensitive method for the detection, quantitation and purification of peptides is described. The method is based on pre-column derivatization of peptides with phenyl isothiocyanate to form phenylthiocarbamoyl derivatives (PTC peptides). The derivatized peptides are analysed by reversed-phase high-performance liquid chromatography on a Zorbax ODS column (5 micron) and detected at 269 nm with a sensitivity limit of 1-5 pmol. The technique was utilized for the separation of a mixture of closely related synthetic peptides. The eluted PTC peptides were collected with an average recovery yield of 75% as determined by amino acid analysis. This method of separation of PTC peptides was also combined with the determination of the complete structure of recovered PTC-dynorphin A-(1-13) using the solid-phase sequenator (Sequemat). The advantages of the derivatization method are the rapidity and completeness of the reaction, the stability of the product, the sensitivity and specificity of the detection of derivatized peptides and the compatibility of the technique with subsequent analytical procedures. A particular application of this method was exemplified by the dosage of enkephalins secreted from perfused bovine adrenal glands.

Adrenal Medulla↗
PubMed1988

Release of calcium from the endoplasmic reticulum by bile acids in rat liver cells.

The effects of four bile acids on cell Ca2+ were examined in suspensions of isolated rat hepatocytes. Taurolithocholate and lithocholate which inhibit bile secretion increased the cytosolic Ca2+ concentration (ED50, 25 microM), as measured by the fluorescent indicator quin2, and promoted a net loss of Ca2+ from the cells. This effect resulted from rapid mobilization of Ca2+ from an intracellular Ca2+ store. This store corresponds to the one that is permeabilized by the inositol (1,4,5)trisphosphate-dependent hormone vasopressin. However, taurolithocholate and lithocholate, unlike the hormone, did not induce a significant accumulation of inositol trisphosphate fraction in isolated hepatocytes. In addition, these agents did not alter the cell and the mitochondria membrane permeability to ions. When applied to saponin-permeabilized cells, taurolithocholate and lithocholate released Ca2+ (ED50, 20 microM) from an ATP-dependent, nonmitochondrial pool which is sensitive to inositol (1,4,5)trisphosphate. In contrast, the bile acids taurocholate and cholate, which increase bile secretion, had no effect on cell Ca2+ in intact hepatocytes or in saponin-permeabilized hepatocytes. It is suggested that taurolithocholate and lithocholate permeabilize the endoplasmic reticulum to Ca2+ and that the resulting permeabilization of this compartment may be involved in the inhibition of bile secretion in mammalian liver.

Animals↗
PubMed1988

Effect of the bile acid taurolithocholate on cell calcium in saponin-treated rat hepatocytes.

Neomycin was used to assess the involvement of Ins (1,4,5)P3 in the Ca2+ release from the endoplasmic reticulum induced by the bile acid taurolithocholate. In saponin-permeabilized rat hepatocytes, neomycin via its ability to bind Ins (1,4,5)P3 abolished the release of Ca2+ induced by added Ins (1,4,5)P3. In contrast, it did not alter the Ca2+ release initiated by the bile acid. In intact cells, neomycin had no effect on the [Ca2+]i rises promoted by taurolithocholate and vasopressin. It is suggested that the effect of taurolithocholate in liver is not mediated by Ins (1,4,5)P3 but results from a primary action on endoplasmic reticulum.

Animals↗
PubMed1988

Sensitivity and specificity of microscopic examination of gallbladder bile for gallstone recognition and identification.

During cholecystectomy, gallbladder bile and gallstones were obtained from 77 patients and gallbladder bile was obtained from 39 patients free of stones (11 patients had biliary stenosis). According to their chemical composition, gallstones were classified as cholesterol (n = 46) or pigment (n = 31) stones. In patients with gallstones (a) cholesterol crystals better helped to identify cholesterol gallstones (sensitivity, 87%; specificity, 97%; positive predictive value, 97%) than did an abnormal cholesterol saturation index of bile (sensitivity, 93%; specificity, 48%; positive predictive value, 73%); (b) the presence of cholesterol crystals was significantly related to the cholesterol content of gallstones and the bile cholesterol saturation index; and (c) bilirubinate crystals, when present alone (without cholesterol crystals), were good predictors of pigment gallstones (sensitivity, 71%; specificity, 93%; positive predictive value, 88%). In the absence of stones, bilirubinate crystals were present in 9 of 28 patients without biliary stenosis (4 with alcoholic cirrhosis and 2 with alcoholic pancreatitis) and 8 of 11 patients with biliary stenosis. In the absence of stones, cholesterol crystals were present in 2 of 28 patients without biliary stenosis and in 4 of 11 patients with biliary stenosis, suggesting that bile stasis can induce cholesterol crystal formation.

Adult↗
PubMed1988

Inhibitory effect of homologous solubilized zona pellucida on rabbit in vitro fertilization.

Rabbit zonae pellucidae were isolated using a modified technique of Dunbar et al. (1980). Zonae pellucidae were solubilized in saline phosphate buffer (pH 7.8) for 30 min at 70 degrees C. One dimensional SDS-PAGE analysis showed that zona pellucida is essentially composed of three major proteins with apparent molecular weights of 200 (275-165) kd, 100 (135-96) kd and 75 (96-51) kd. Preincubation of sperm with heat-solubilized zonae pellucidae (SZP) (5 to 8 SZP/microliters) did not reduce sperm binding ability. By contrast, it significantly decreased the percentage of penetrated eggs (20 versus 73% for the control) and significantly reduced the fertilization rate (10 versus 55% for the control). Ultrastructural analysis of several oocytes in the two groups demonstrated that inhibition of fertilization was not due to the inhibition of sperm-zona binding ability but essentially resulted from the impairment of sperm penetration through the zona pellucida.

Acrosome↗
PubMed1988

Cholestatic effect of cyclosporine in the rat. An inhibition of bile acid secretion.

Cyclosporine administration in patients with organ transplants may cause cholestasis. In the rat, intraperitoneal administration of cyclosporine, 10 mg/kg, for three weeks did not cause liver function test abnormalities or hepatic histological lesions. However a significant reduction of bile flow and bile acid secretion rates was observed. The fact that reduction of bile flow was related to a decrease of the bile acid-independent flow suggests that cyclosporine-induced cholestasis results from an inhibition of bile acid secretion. Whether this inhibition is caused by the parental molecule or by cyclosporine metabolites needs to be clarified.

Animals↗
PubMed1988

Immunoperoxidase localization of bile salts in rat liver cells. Evidence for a role of the Golgi apparatus in bile salt transport.

The mechanisms of intracellular transport of bile acids from the sinusoidal pole to the canalicular pole of the hepatocyte are poorly understood. There is physiological and autoradiographic evidence for a vesicular pathway. The purpose of this study was to determine the localization of natural bile acids in the liver using antibodies against cholic acid conjugates and ursodeoxycholic acid. An indirect immunoperoxidase technique was used on rat liver sections fixed either with paraformaldehyde (PF) and saponin, a membrane-permeabilizing agent that allows penetration of antibodies into the cell, or with PF alone. Retention of taurocholate in the liver after tissue processing was 26 +/- SD 15% of the bile acid initially present. When sections fixed with PF and saponin were incubated with the antibody against cholic acid conjugates, a granular cytoplasmic staining was observed by light microscopy in all hepatocytes. By electron microscopy, strong electron-dense deposits were observed mostly on vesicles of the Golgi apparatus (GA) and, sometimes, in the smooth endoplasmic reticulum (SER). After taurocholate infusion, the intensity of the reaction increased. When the liver was fixed with PF alone, almost no reaction was visible on light microscopy, but on electron microscopy the label was localized on the hepatocyte plasma membrane, mainly on the bile canalicular domain and to a lesser extent on the sinusoidal domain. With the antibody against ursodeoxycholic acid, no staining was observed in three of four livers, and a slight staining was observed in one. However, after infusion of ursodeoxycholic acid, staining of GA and SER vesicles was observed when the liver was fixed with PF and saponin. With PF alone, the reaction was intense on the canalicular membrane. These results support the view that, within the limits of the method, vesicles from the GA and possibly vesicles of the SER are involved in the intracellular transport of bile acids before canalicular secretion.

Animals↗
PubMed1988

[Nicolas Puzos: an obstetrician of the 18th century. From military surgery to obstetrics and from milk fever to placenta praevia].

Nicolas Puzos (1686-1753) was a famous french obstetrician in Paris during the 18th century. When he was sixteen years old, his father sent him as aide-major to follow the armies of Louis XIV to learn military surgery. After this he became an obstetrician studying with his master, a friend of his father, Julien Clément, accoucheur to the Court. Puzos while working wrote many notes which were assembled in a book after his death by Morisot-Deslandes: "Traité des Accouchements de M. Puzos", published in 1759. Puzos was the first to advocate rupture and tearing of the membranes in the treatment of haemorrhage brought about by placenta praevia partialis or marginalis. This "Puzos' method" as it is even now sometimes called in France, was aimed to replace "accouchement forcé" followed by version and was discussed by Leroux of Dijon who advocated the vaginal pack or tamponade. The "Puzos' method" was adopted until the current use of cesarean section.

France↗
PubMed1988

[Unusual historical cases of uterine inversion].

Professor Martial Dumont presents four cases of inverted uterus which are quite old. They come from the book by Mr Planque, M.D., entitled: "Selected Medical Library, from periodical publications, French as well as Foreign", published in Paris in 1748, by D'Houry senior, publisher and bookseller of His Royal Highness the Duke of Orleans, rue de la Vieille Boucherie. These findings are reported in Volume One, pages 406-413.

Female↗
PubMed1988

[Hepatobiliary changes during exclusive parenteral feeding in infants with severe diarrhea].

In order to specify the factors responsible for the hepatic changes occurring during total parenteral nutrition (TPN) and to propose a preventive treatment, 30 infants treated for severe protracted diarrhea were prospectively distributed into 4 groups: I (n = 10): controls; II (n = 7): oral administration of human milk since the 15th day of TPN; III (n = 5): oral metronidazole since the 15th day; IV (n = 8): parenteral antibiotic therapy for septicemia since the 1st day. Contrary to group IV, the first 3 groups were randomly constituted on the 15th day. Liver function tests, bile and serum biliary acids, duodenal flora, hepato-biliary ultrasonography and, in 12 cases, liver histology were sequentially studied. Liver function changes were observed on the 15th day in all groups. An improvement occurred 15 days later in the infants treated, when the control group worsened (p less than 0.02). A significant increase of bile chenodeoxycholic acid levels was observed in the control group only (p less than 0.01), without change in lithocholic acid levels. These results lead the authors to recommend the preventive use of metronidazole or human milk during prolonged TPN in infants.

Bile Acids and Salts↗
PubMed1988

[The wanderings of Jules Cloquet and Gustave Flaubert].

This is the story of a picaresque journey in France and in Corsica of Jules Cloquet (1790-1883), the French anatomist who described the well-known Cloquet's node and of Gustave Flaubert (1821-1880), the famous author of "Madame Bovary" and of many others novels. They were two vagabonds, Cloquet watching with slackness the young womanizering Flaubert. At 64 years of age, the lazy and meddlesome Cloquet stopped operating and writing. Surrounded by honors, he died at the age of 93, leaving his eponym to the Cloquet's node.

Anatomy↗
PubMed1988

[Spontaneous perforation of the cecum after cesarean section].

The literature concerning perforation and imminent perforation of the caecum after cesarean section is reviewed. One case has been observed by the author. Increasing caecal diameter above 10 cm gives rise to suspicion of an imminent perforation of the caecum. Medical treatment and colonoscopy may be tried. In case of unresponsiveness or if occurrence of a cecal perforation, surgical intervention (cecostomy) is indicated.

Adult↗
PubMed1987

Clinical and sleep laboratory study of narcoleptic symptoms in multiple sclerosis.

Seventy white patients with a diagnosis of MS and typed for their HLA-A, B, C, and DR were studied. A clinical interview and a questionnaire were used to evaluate the presence of narcoleptic symptoms. The prevalence of sleep attacks, cataplexy, and sleep paralysis was significantly elevated among these patients. However, no difference was seen between DR2 and non-DR2 subjects with regard to the incidence of narcoleptic symptoms. Nine DR2 patients complaining of both sleep attacks and cataplexy were studied in the sleep laboratory for five consecutive naps, but no polygraphic evidence of narcolepsy was found.

Adult↗