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G Parmentier

Publications and source records attributed to G Parmentier.

At least 19 recordsLinked to original sources
PubMed1995

[Generalised peritonitis complicating colonic diverticulosis. Associations de Recherche en Chirurgie].

Perforated diverticulitis is an uncommon but severe complication of diverticular disease. Whatever the type of the contamination, whether bacterial or fecal, the peritonitis is responsible for septic shock, which necessitates emergent and aggressive medical and surgical treatment. Intensive intravenous perfusion under monitoring, adapted antibiotherapy should come before surgical decision. The aim of surgery is twofold: to suppress the infectious source and to clean the peritoneum. After all, the peritonitis has a tendency to recur and therefore postoperative abscesses have to be searched systematically and if the case arises, these abscesses have to be reoperated or drained. Best results were obtained with immediate sigmoidectomy and colo-rectal anastomosis associated with loop colostomy; that procedure should be preferred to Hartmann technique. If the morbidity remains high, the mortality should decrease under 10% with intensive therapy.

Adult↗
PubMed1992

Alpha-oxidation of 3-methyl-substituted fatty acids in rat liver.

3-Methyl-substituted fatty acids are first oxidatively decarboxylated (alpha-oxidation) before they are degraded further via beta-oxidation. We synthesized [1-14C]phytanic and 3-[1-14C]methylmargaric acids in order to study their alpha-oxidation in isolated rat hepatocytes, rat liver homogenates and subcellular fractions. alpha-Oxidation was measured as the production of radioactive CO2. In isolated hepatocytes, maximal rates of alpha-oxidation amounted to 7 and 10 nmol/min x 10(8) cells with phytanic acid and 3-methylmargaric acid, respectively. At equimolar substrate concentrations, alpha-oxidation of branched fatty acids was approximately 10- to 15-fold slower than the beta-oxidation of the straight chain palmitate. In whole liver homogenates, rates of alpha-oxidation that equaled 60 to 70% of those observed in the hepatocytes were obtained. Optimum rates required O2, NADPH, Fe3+, and ATP. Fe3+ could be replaced by Fe2+ and ATP could be replaced by a number of other phosphorylated nucleosides and even inorganic phosphate without loss of activity. NADH could substitute for NADPH but not always with full restoration of activity. A variety of other cofactors and metal ions was either inhibitory or without effect. Scavengers of reactive oxygen species, known to be formed during the NADPH-dependent microsomal reduction of ferric-phosphate complexes, were without effect on alpha-oxidation. No evidence was found for the accumulation of NADPH-dependent or Fe(3+)-dependent reaction intermediates. Subcellular fractionation of liver homogenates demonstrated that alpha-oxidation was located predominantly, if not exclusively, in the endoplasmic reticulum. alpha-Oxidation, measured in microsomal fractions, was not inhibited by CO, cytochrome c, or ferricyanide, indicating that NADPH cytochrome P450 reductase and cytochrome P450 are not involved in alpha-oxidation. Our results indicate that, contrary to current belief, alpha-oxidation is catalyzed by the endoplasmic reticulum. The cofactor requirements suggest that alpha-oxidation involves the reduction of Fe3+ by electrons from NADPH and that it is stimulated by phosphate ions and nucleotides.

Animals↗
PubMed1991

Identification and purification of a peroxisomal branched chain fatty acyl-CoA oxidase.

Isoprenoid (branched) fatty acids such as pristanic acid can be degraded via beta-oxidation in peroxisomes. We synthesized 2-methylpalmitoyl-CoA as a model substrate in order to study the first step of the peroxisomal beta-oxidation of branched fatty acids, catalyzed by an acyl-CoA oxidase. 2-Methylpalmitoyl-CoA oxidase activity was found in rat liver homogenates. Subcellular fractionation demonstrated that the oxidase was confined to peroxisomes. 2-Methylpalmitoyl-CoA oxidase was also present in kidney and intestine. It was not induced in liver or in the extrahepatic tissues by treatment of rats with peroxisome proliferators or by feeding diets containing excess isoprenoids. The enzyme was partially purified together with palmitoyl-CoA oxidase and trihydroxycoprostanoyl-CoA oxidase by heat treatment and ammonium sulfate fractionation of liver extracts. The partially purified preparation was chromatographed on various columns. 2-Methylpalmitoyl-CoA oxidase could be separated from the inducible (by peroxisome proliferators) palmitoyl-CoA oxidase and from trihydroxycoprostanoyl-CoA oxidase, but it always coeluted with the noninducible palmitoyl-CoA oxidase, recently described by us (Schepers, L., Van Veldhoven, P. P., Casteels, M., Eyssen, H. J., and Mannaerts, G. P. (1990) J. Biol. Chem. 265, 5242-5246). 2-Methylpalmitoyl-CoA oxidase was purified to near homogeneity in three chromatographic steps (anion exchange, hydroxylapatite, and gel filtration). Its apparent molecular mass is approximately 415 kDa, and it consists of identical subunits of approximately 70 kDa. The enzyme oxidized 2-methylpalmitoyl-CoA twice as rapidly as palmitoyl-CoA and pristanoyl-CoA as rapidly as palmitoyl-CoA, so that it can be considered as a branched fatty acyl-CoA oxidase. Since pristanoyl-CoA is one of its naturally occurring substrates we propose to name this enzyme pristanoyl-CoA oxidase.

Animals↗
PubMed1991

Mitochondrial and peroxisomal beta oxidation of the branched chain fatty acid 2-methylpalmitate in rat liver.

A number of isoprenoids (e.g. pristanic acid and the side chains of fat soluble-vitamins) is degraded or shortened via beta oxidation. We synthesized 2-methyl-palmitate and 2-methyl[1-14C] palmitate as a model substrate for the study of the beta oxidation of branched (isoprenoid) fatty acids in rat liver. 2-Methylpalmitate was well oxidized by isolated hepatocytes and its oxidation was stimulated after treatment of the animals with a peroxisome proliferator. Subcellular fractionation of rat liver demonstrated that 2-methylpalmitate is activated to its CoA ester in endoplasmic reticulum, mitochondria, and peroxisomes and that mitochondria and peroxisomes are capable of beta-oxidizing 2-methylpalmitate. At low unbound 2-methylpalmitate concentrations and in the presence of competing straight chain fatty acids, a condition encountered in vivo, peroxisomal 2-methyl-palmitate oxidation was 2- to 4-fold more active than mitochondrial oxidation. Treatment of rats with a peroxisome proliferator markedly stimulated mitochondrial but only slightly peroxisomal 2-methylpalmitate oxidation. The same treatment dramatically induced palmitoyl-CoA oxidase but did not change 2-methyl-palmitoyl-CoA oxidase activity. Our results indicate 1) that in untreated rats peroxisomes contribute for an important part to the oxidation of 2-methylpalmitate; 2) that treatment with a peroxisome proliferator stimulates mainly the mitochondrial component of 2-methylpalmitate oxidation; and 3) that palmitoyl-CoA and 2-methylpalmitoyl-CoA are oxidized by different peroxisomal oxidases.

Acyl-CoA Oxidase↗
PubMed1991

Partial characterization of the steroidsulfatases in Peptococcus niger H4.

The strictly anaerobic intestinal Peptococcus niger H4 synthesizes three different steroidsulfatase enzymes: a constitutive arylsulfatase and two inducible alkylsteroidsulfatases. The arylsulfatase desulfates estrogen-3-sulfates and phenylsulfates. The two alkylsteroidsulfatases desulfate, respectively, 3 alpha-sulfates and 3 beta-sulfates of delta 5, 5 alpha, and 5 beta androstanes, pregnanes, and bile acids. Cholesterol-3 beta-sulfate was not desulfated by the alkylsteroidsulfatases nor were steroids or bile acids that were sulfated in positions other than the 3 position. The alkylsteroidsulfatases were induced by their substrates; bile acid sulfates, however, were poor inducers of the 3 beta-sulfatase and did not induce the 3 alpha-sulfatase activity. In intact bacterial cells, taurine and sulfite suppressed the induction of the alkylsteroidsulfatases and inhibited the activity of the arylsulfatase and alkylsteroidsulfatases. In cell homogenates, the arylsulfatase and alkylsteroidsulfatases activities were inhibited by sulfite and sulfate but not by taurine. Our results support the hypothesis that the main function of the steroidsulfatases in P. niger H4 is to provide the bacteria with sulfur for dissimilatory purposes.

Arylsulfatases↗
PubMed1989

Subcellular distribution and characteristics of trihydroxycoprostanoyl-CoA synthetase in rat liver.

The subcellular distribution and characteristics of trihydroxycoprostanoyl-CoA synthetase were studied in rat liver and were compared with those of palmitoyl-CoA synthetase and choloyl-CoA synthetase. Trihydroxycoprostanoyl-CoA synthetase and choloyl-CoA synthetase were localized almost completely in the endoplasmic reticulum. A quantitatively insignificant part of trihydroxycoprostanoyl-CoA synthetase was perhaps present in mitochondria. Peroxisomes, which convert trihydroxycoprostanoyl-CoA into choloyl-CoA, were devoid of trihydroxycoprostanoyl-CoA synthetase. As already known, palmitoyl-CoA synthetase was distributed among mitochondria, peroxisomes and endoplasmic reticulum. Substrate- and cofactor- (ATP, CoASH) dependence of the three synthesis activities were also studied. Cholic acid and trihydroxycoprostanic acid did not inhibit palmitoyl-CoA synthetase; palmitate inhibited the other synthetases non-competitively. Likewise, cholic acid inhibited trihydroxycoprostanic acid activation non-competitively and vice versa. The pH curves of the synthetases did not coincide. Triton X-100 affected the activity of each of the synthetases differently. Trihydroxycoprostanoyl-CoA synthetase was less sensitive towards inhibition by pyrophosphate than choloyl-CoA synthetase. The synthetases could not be solubilized from microsomal membranes by treatment with 1 M-NaCl, but could be solubilized with Triton X-100 or Triton X-100 plus NaCl. The detergent-solubilized trihydroxycoprostanoyl-CoA synthetase could be separated from the solubilized choloyl-CoA synthetase and palmitoyl-CoA synthetase by affinity chromatograpy on Sepharose to which trihydroxycoprostanic acid was bound. Choloyl-CoA synthetase and trihydroxycoprostanoyl-CoA synthetase could not be detected in homogenates from kidney or intestinal mucosa. The results indicate that long-chain fatty acids, cholic acid and trihydroxycoprostanic acid are activated by three separate enzymes.

Animals↗
PubMed1989

By-products in the analysis of beta-muricholic acid in biological samples as methyl ester triacetate.

By-products were formed on analysis of beta-muricholic acid (3 alpha, 6 beta, 7 beta-trihydroxy-5 beta-cholan-24-oic acid) in biological samples by a method involving acid-catalyzed solvolysis of sulfate esters in acetone-methanol, followed by perchloric acid-catalyzed acetylation with acetic anhydride-acetic acid. These products have been identified by mass spectrometry and nuclear magnetic resonance as methyl 3-0,6-0-diacetyl-7-0-(1-methyl-3-oxo-1-butenyl)- and methyl 3-0,7-0-diacetyl-6-0-(1-methyl-3-oxo-1-butenyl)-beta-muricholate, methyl 3-0, 6-0-diacetyl- and methyl 3-0, 7-0-diacetyl-beta-muricholate, and a methyl diacetoxy-cholen-24-oate.

Acetylation↗
PubMed1989

Activation and peroxisomal beta-oxidation of fatty acids and bile acid intermediates in liver from Bombina orientalis and from the rat.

1. Bombina orientalis excretes mainly C27 bile acids: trihydroxycoprostanic and varanic acids. More than 90% of the trihydroxycoprostanic acid (THCA) present in the bile, was conjugated with taurine; varanic acid was present in the unconjugated form. 2. Trihydroxycoprostanoyl-CoA (THC-CoA) synthetase activity, required for the formation of the taurine conjugate, was present in the liver of Bombina orientalis. 3. Peroxisomal beta-oxidation, which catalyzes the oxidation of fatty acids as well as the conversion of C27 bile acids into C24 bile acids in rat and human liver, could be detected in liver of Bombina orientalis when palmitoyl-CoA was used as substrate, but not when trihydroxycoprostanoyl-CoA (THC-CoA) was used.

Animals↗
PubMed1989

Selective activity of several cholic acid derivatives against human immunodeficiency virus replication in vitro.

Several cholic acid derivatives such as taurolithocholic acid, lithocholic acid 3-sulfate, taurolithocholic acid 3-sulfate, and glycolithocholic acid 3-sulfate were shown to inhibit selectively the replication of human immunodeficiency virus type 1 (HIV-1) in vitro. These compounds completely protected MT-4 cells against HIV-1-induced cytopathogenicity at a concentration of 100 micrograms/ml, whereas no toxicity for the host cells was observed at 200 micrograms/ml. They also inhibited HIV-1 antigen expression in HIV-1-infected CEM cells. The bile acids (cholic acid, deoxycholic acid, chenodeoxycholic acid, and lithocholic acid) did not show any inhibitory effect on HIV-1 replication at concentrations that were not toxic to the host (MT-4) cells. From a structure-function analysis of a number of cholic acid derivatives, the presence of either a sulfonate (as in the tauro conjugates) or a sulfate group as well as the "litho" configuration appeared to be necessary for the expression of anti-HIV-1 activity. The active cholic acid derivatives did not directly inactivate the virus particles at the concentrations that were not toxic to the host cells. Lithocholic acid 3-sulfate, taurolithocholic acid 3-sulfate, and glycolithocholic acid 3-sulfate, but not taurolithocholic acid, partially inhibited virus adsorption to MT-4 cells. These three compounds were also inhibitory to the reverse transcriptase activity associated with HIV-1.

Adsorption↗
PubMed1988

Beta-oxidation of the carboxyl side chain of prostaglandin E2 in rat liver peroxisomes and mitochondria.

Rat liver and kidney homogenates, fortified with the appropriate cofactors, produced H2O2 when incubated with prostaglandin (PG) E2 or its CoA ester (PGE2-CoA), indicating that PGE2-CoA served as substrate for acyl-CoA oxidase, the first enzyme of peroxisomal beta-oxidation. PGE2-CoA oxidase was stimulated to the same extent as palmitoyl-CoA oxidase by treatment of rats with the peroxisome proliferator clofibrate. Subcellular fractionation confirmed that both oxidase activities were located in peroxisomes. When highly purified peroxisomes were incubated with [1-14C]PGE2, radioactive oxidation products were released, demonstrating that peroxisomes were capable of catalyzing the complete beta-oxidation sequence. However, PGE2 beta-oxidizing activity was expressed only when isolated microsomes were added to the purified peroxisomes, indicating that PGE2-CoA synthetase is located in the endoplasmic reticulum. Cofactor requirements for peroxisomal [1-14C]PGE2 and [1-14C]palmitate oxidation were identical, and oxidation was not inhibited by cyanide. [1-14C]PGE2 was also beta-oxidized by highly purified mitochondrial fractions, devoid of peroxisomes, when microsomes were added. Mitochondrial [1-14C]PGE2 and [1-14C]palmitate oxidation was CoA- and ATP-dependent and inhibited by cyanide. Palmitate oxidation was carnitine-dependent, but PGE2 oxidation was not. Acyl-CoA dehydrogenase activity, but not carnitine acyltransferase activity, was detected with PGE2-CoA as substrate. [1-14C]PGE2 oxidation in whole liver homogenates was only slightly inhibited by cyanide, indicating that peroxisomes oxidized the major portion of PGE2. The concentrations of PGE2 employed in these experiments exceeded the in vivo concentrations by several orders of magnitude. Therefore, we suggest that the urinary PG metabolite excretion be measured in patients with hereditary diseases in which peroxisomal or mitochondrial beta-oxidation is not functioning in order to clarify the role of each organelle in PG oxidation in vivo.

Animals↗
PubMed1988

[Budd-Chiari syndrome with thrombosis of the inferior vena cava. Treatment by mesenterico-innominate shunt].

We report two cases of patients, 12 and 28 years old, suffering from a Budd-Chiari syndrome with a thrombosed inferior vena cava, who were treated by a shunt interposed between the superior mesenteric vein and the left innominate vein. The aim of this shunt was to avoid pericardiotomy in these patients with peroperative ascites, in order to reduce the risk of pericarditis after surgery. A reinforced polytetrafluoroethylene prosthesis (Gore-Tex) was used, associated with an interposition jugular vein graft in the 12-year old child, alone in the other case. The left innominate vein was isolated through a midline sternotomy, and the prosthesis was placed in a retrosternal position. Operation and postoperative course were uneventful. All signs of ascites disappeared. The patients were free of symptoms, 8 and 4 months after surgery respectively. Shunt patency was documented by angiography and magnetic nuclear resonance.

Adult↗
PubMed1987

Inhibition of peroxisomal fatty acyl-CoA oxidase by antimycin A.

Peroxisomal fatty acyl-CoA oxidase was inhibited by micromolar concentrations of antimycin A, an inhibitor of mitochondrial respiration. The inhibition was observed with all three substrates tested, i.e. palmitoyl-CoA, trihydroxycoprostanoyl-CoA and hexadecanedioyl-CoA. The peroxisomal D-amino acid oxidase was also inhibited by antimycin, but the peroxisomal L-alpha-hydroxyacid oxidase and uric acid oxidase and the mitochondrial monoamine oxidase were not. The degree of inhibition of acyl-CoA oxidase by antimycin was strongly dependent on the amount of cellular protein present in the assay mixture: at a fixed antimycin concentration, the inhibition was gradually lost with increasing protein concentrations. At a fixed cellular protein concentration in the assay mixtures, the mitochondrial oxidation of glutamate or palmitoylcarnitine was inhibited at antimycin concentrations that were much lower than those required for the inhibition of fatty acyl-CoA oxidase. Our results, nevertheless, demonstrate that antimycin A must be used with caution, when it is added to homogenates or subcellular fractions in order to distinguish between mitochondrial and peroxisomal fatty acid oxidation.

Acyl-CoA Oxidase↗
PubMed1987

Influence of an estrone-desulfating intestinal flora on the enterohepatic circulation of estrone-sulfate in rats.

The fecal and urinary excretion of orally administered [4-14C]estrone-3-sulfate was studied in germfree (GF) rats, conventional (CV) rats and gnotobiotic rats selectively associated with estrone-desulfating and/or cecal-volume reducing microorganisms. The time required to excrete 50% of the total label recovered (t 1/2) was 22 h in CV rats vs 32 h in GF rats. Gnotobiotic rats selectively associated with a cecal volume-reducing flora (CRF rats) excreted the label even faster (t 1/2 = 13 h) than CV rats. Association of GF rats as well as CRF rats with estrone-desulfating microorganisms (termed S1 + S2 + R9 rats and CRF + S1 + S2 + R9 rats, respectively) led to a slower excretion of labeled products (t 1/2 = 38 h in S1 + S2 + R9 rats and t 1/2 = 27 h in CFR + S1 + S2 + R9 rats). Intestinal microbial desulfation also increased the relative part of the urinary excretion from 4% in GF rats to 8% in S1 + S2 + R9 rats and from 3% in CRF rats to 9% in CFR + S1 + S2 + R9 rats. We conclude that intestinal microbial desulfation enhances the enterohepatic circulation of orally administered estrone-3-sulfate.

Animals↗
PubMed1986

[Peridural anesthesia with procaine and fentanyl in a parturient with acute intermittent porphyria].

Acute intermittent porphyria is one of three severe hepatic porphyrias. Clinical manifestations include intermittent acute attacks of abdominal pain and neuropathy with an occasionally outcome. These attacks are often precipitated by endogenous (menstrual cycle and pregnancy in women) or exogenous factors (porphyrinogenic drugs). An epidural analgesia was performed during the labour of a pregnant woman with acute intermittent porphyria just after an acute attack of abdominal pain. Analgesia was obtained using procaine and fentanyl. The choice of drugs was based on available clinical reports and experimental studies of the porphyrinogenicity of drugs in animal models (rat in vivo and chick embryo in ovo).

Acute Disease↗
PubMed1986

Isolation of a rat intestinal Clostridium strain producing 5 alpha- and 5 beta-bile salt 3 alpha-sulfatase activity.

An unnamed sporeforming microorganism, termed Clostridium sp. strain S2, possessing bile salt sulfatase activity was isolated from rat intestinal microflora. The microorganism was a strictly anaerobic, nonmotile, gram-negative, asaccharolytic, sporeforming rod requiring CO2, vitamin K, and taurine; the guanine-plus-cytosine content of the DNA was 40.8 mol% (Tm), and the strain was tentatively classified as an atypical Clostridium species. Sulfatase activity was specific for 3 alpha-sulfate esters of 5 alpha- and 5 beta-bile salts, leaving the 3 beta-, 7 alpha-, and 12 alpha-sulfates unchanged. Strain S2 also deconjugated tauro- and glyco-conjugated bile salts and partially reduced into the corresponding 6 alpha-hydroxy bile salts. By these reactions, alpha-muricholate and beta-muricholate were more than 80% converted into hyocholate and omega-muricholate, respectively. In addition, strain S2 produced 12 alpha-hydroxysteroid dehydrogenase converting deoxycholate into 3 alpha-hydroxy-12-oxo-5 beta-cholanoate. When strain S2 was associated with gnotobiotic rats, the fecal bile salts were more than 90% desulfated and the fecal excretion of allochenodeoxycholate was five times lower than in control rats.

Animals↗
PubMed1985

Influence of microbial bile salt desulfation upon the fecal excretion of bile salts in gnotobiotic rats.

The fecal excretion of intraperitoneally injected 24-14C-labeled taurocholate (TCA), taurolithocholate (TLCA) and the respective 3-sulfate esters (TCA-3-S; TLCA-3-S), were compared in germfree (GF) rats, conventional (CV) rats, and in gnotobiotic rats associated with Clostridium Cl-8 or this same strain Cl-8 plus the bile desulfating Clostridium S1, respectively. TCA and TLCA were about two times more rapidly excreted by CV animals than by GF animals; the time required for 50% excretion of total label injected (t 1/2) was 6.6 days vs 14.9 for TCA, and 4.4 vs 8.9 for TLCA. In GF and in CV animals, TCA-3-S and TLCA-3-S were excreted more rapidly than their nonsulfated analogues; the t 1/2 values of TCA-3-S and TCA were 2.7 days vs 14.9 in GF rats, and 3.1 vs 6.6 days in CV animals. The t 1/2 values of TLCA-3-S and TLCA were 2.7 days vs 8.9 in GF rats, and 1.5 vs 4.4 days in CV rats. In gnotobiotic rats associated with Clostridium strains S1 + Cl-8, fecal bile salts were nearly 100% deconjugated and desulfated and the 50% excretion times of TCA-3-S and TLCA-3-S approximated to those of TCA and TLCA in GF animals. T 1/2 of TCA-3-S in gnotobiotic S1 + Cl-8 animals was 12.2 days vs 14.9 for TCA in GF animals. In gnotobiotic S1 + Cl-8 animals the t 1/2 of TLCA and TLCA-3-S was 12.5 and 11.0 days, respectively. These results illustrate clearly the important effect the intestinal microflora has upon the metabolic half-life of bile salts. Moreover, they demonstrate that desulfation of bile salts by the intestinal microflora takes place in intestinal segments from where a certain degree of reabsorption is still possible, and thus point to the fact that microbial desulfation is an important variable in the overall elimination of bile salts.

Animals↗
PubMed1985

Bile acid abnormalities and the diagnosis of cerebro-hepato-renal syndrome (Zellweger syndrome).

The Zellweger or cerebro-hepato-renal syndrome (CHRS) is a congenital disorder characterized by cerebral dysfunction, craniofacial dysmorphic features, transient cholestasis and renal cysts. Patients fail to thrive, and usually die in their first year of life. In some cases, a definite diagnosis on purely clinical signs might not be possible. Several biochemical abnormalities have been observed in these patients and some of them have been tested as diagnostic markers. The aim of this study is to evaluate bile acid metabolites as biochemical markers of the CHRS. From a study of 20 CHRS patients, we conclude that screening for the presence of coprostanic acids and the C-29 dicarboxylic bile acid in serum or urine is for detection of CHRS and confirmation of the diagnosis.

Bile Acids and Salts↗