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A F Petavy

Publications and source records attributed to A F Petavy.

At least 37 records · Page 2Linked to original sources
PubMed1994

Gangliosides of Echinococcus multilocularis metacestodes.

Gangliosides, glycosphingolipids with sialic acid, were found in metacestodes of Echinococcus multilocularis in low quantities. All gangliosides were resolved after preparative high-performance thin layer chromatography into four fractions. Cholera toxin was specifically bound to the major ganglioside, allowing the identification of it as a GM1. Precise structure of the four fractions was determined by sequential degradation by exoglycosidases, gas chromatography, electron impact mass spectrometry and liquid secondary ion-mass spectrometry. Beside GM1, the other fractions were GM3, GD1a and, at a lesser percentage, GM2, all belonging to the same a-ganglio-series. The ceramide part of these parasite gangliosides contained sphingosine associated to unsaturated n24, saturated n24 and n16 fatty acids.

Animals↗
PubMed1994

Echinococcus multilocularis: in vitro interactions between protoscolices and Kupffer cells.

Echinococcus multilocularis protoscolices collected from experimentally infected jirds were incubated for 2 weeks in rat hepatic cell cultures cocultivated with or without feeder cells (BALB/c 3T3 and IAR 20). Scanning and transmission electron microscopy studies were performed during the course of the culture period. Kupffer cells (Kc) were seen adhering to the anterior and posterior ends of the protoscolices. Some protoscolices were fixed to the cell monolayer by a cluster of Kc adhering to the posterior end of the parasite. These cells were phagocytosing the glycocalyx and the electron-dense distal end of the microthrix of the protoscolex tegument. An alteration in the superficial tegumental cytoplasm with extensive mitochondrial damage was also noted. The properties expressed by Kc against protoscolices in vitro might also be relevant for proliferation of metacestodes in vivo.

Animals↗
PubMed1994

Purification and characterization of the alkaline phosphatase from Echinococcus granulosus cyst membranes.

The purification to homogeneity and the characterization of Echinococcus granulosus alkaline phosphatase (AP; EC 3.1.3.1) from hydatid cyst membranes are described. After n-butanol extraction, the parasite enzyme was sequentially purified by affinity chromatography on concanavalin A-sepharose followed by gel filtration. The purified protein (210 kDa) had a tetrameric structure composed of 4 56-kDa subunits. Its isoelectric point (4.8) and its kinetic parameters were determined (Km = 0.24 +/- 0.05 mmol/L; Vm = 173 +/- 21 nmol/min/mg protein for p-nitrophenylphosphate). The parasite enzyme differed from the host liver enzyme in its thermal stability, optimum reaction temperature, optimum pH, and catalytic parameters, but not in its apparent molecular weight. Furthermore, sera from patients infected with E. granulosus recognized the parasite AP on immunoblots, whereas uninfected controls were negative. These results as well as the role of this enzyme in the host-parasite relationship emphasize its potential importance as a diagnostic and prognostic antigen in the monitoring of hydatid infection.

Alkaline Phosphatase↗
PubMed1993

Synthesis of propargylic alcohols and biological effects on Echinococcus multilocularis metacestodes.

This study describes the synthesis of propargylic alcohols derived from isatin and their biochemical and morphological effects on Echinococcus multilocularis metacestodes in Meriones unguiculatus. Propargylic alcohols decreased the alkaline phosphatase and the lactate dehydrogenase activities of the metacestode selectively. The most effective compound, 1b, decreased the lactate dehydrogenase enzymatic activity, and the glucose concentration in the parasite increased, whereas the glycogen content was partially decreased. Furthermore, the ultrastructure study revealed several damages. The host-parasite relationships are very important in the intrahepatic cestodes as shown by the biochemical side effects observed in the host's liver during the treatment. An in vitro enzymatic study was performed with alcohols 1b and 1c.

Alkaline Phosphatase↗
PubMed1993

Echinococcus granulosus:isoprinosine treatment of the metacestode stage.

The efficacy of short- and long-term treatments with Isoprinosine, an immunomodulatory compound, was studied in Echinococcus granulosus cysts developed in NMRI mice intraperitoneally infected with sheep pulmonary cysts. After treatment, a reduction in the size and number of cysts with macroscopic modifications was observed. The structural alterations included damage or destruction of the protoscoleces and partial destruction of the cyst wall, which predominated at the inner germinal layer level. The efficacy of this drug was evaluated after long-term and short-term treatment. Short-term treatment with a dose of 1 g/kg/day gave better results, with a loss of infectivity of the larval tissue. The well-tolerated long-term treatment with a dose of 2 g/kg/day showed the absence of toxicity of this compound. The survival time of treated animals was greater than that of untreated controls.

Animals↗
PubMed1992

Glycosphingolipids with Gal beta 1----6Gal sequences in metacestodes of the parasite Echinococcus multilocularis.

Neutral glycosphingolipids of the metacestodes of Echinococcus multilocularis, an animal and human parasite, were resolved by high performance thin layer chromatography into 12 fractions. Nine of these fractions were permethylated, analyzed by electron impact-mass spectrometry, and submitted to methylation analysis by gas chromatography-mass spectrometry. Native fractions were analyzed by liquid secondary ion-mass spectrometry and degraded sequentially by exoglycosidases. In addition to a previously described galactosylceramide, a di-, a tri-, and a tetragalactosyl-ceramide having Gal beta 1-6Gal internal linkages were characterized. This type of carbohydrate chain has been described in glycolipids of a marine mollusk, Turbo cornutus (Matsubara, T., and Hayashi, A. (1981) J. Biochem. (Tokyo), 89, 645-650). In addition two novel fucolipids were found with the following structures: Fuc alpha 1-3Gal beta 1-6Gal-Cer and Gal beta 1-6(Fuc alpha 1-3)Gal beta 1-6Gal-Cer. Ceramides contained sphinganine and either nonhydroxy fatty acids with 16, 18, 26, and 28 carbon atoms, or hydroxy fatty acids, with 16 and 18 carbon atoms. Di-, tri-, and tetragalactosylceramides containing the Gal beta 1-6Gal disaccharide were found to be immunogenic in humans.

Animals↗
PubMed1992

Effects of multiple doses of isoprinosine on Echinococcus multilocularis metacestodes.

Isoprinosine was given at daily doses of 0.5, 1, 2, and 4 g kg-1 of body weight to jirds that were infected for 3 months with Echinococcus multilocularis metacestodes. The effects of the different drug doses on metacestodes were studied by transmission electron microscopy and biochemical methods. At lower doses, increases in uric acid and adenosine deaminase activity were noted. At 4 g kg-1 of body weight, marked ultrastructural damage with metabolic perturbations was observed.

Adenosine Deaminase↗
PubMed1991

In vivo cultivation of Echinococcus multilocularis protoscoleces in micropore chambers.

Micropore chambers containing unevaginated protoscoleces of E. multilocularis were implanted into the peritoneal cavity of AKR mice. Transformation from protoscoleces to fertile multivesicular cysts was obtained after 210 days. Ultrastructural observations of these morphological transformations indicate that a phase of histogenesis follows a phase of dedifferentiation. This morphogenetic process raises the question of the origin of new cell populations. The results reveal the potential role of protoscoleces in secondary echinococcosis and the value of this experimental model for further studies on the larval development.

Animals↗
PubMed1991

Alkaline phosphatase from Echinococcus multilocularis: purification and characterization.

1. Kinetic and physical parameters of purified alkaline phosphatase from Echinococcus multilocularis metacestodes, livers of infected gerbils and control animals were determined. 2. Km value for p-nitrophenyl phosphate was about 0.05 +/- 0.02 mM for the three enzymes. 3. Vmax values were 357 +/- 67 nmol/min/mg proteins for metacestode enzyme, and 6.7 +/- 1.1 and 6.7 +/- 0.8 nmol/min/mg proteins for liver enzyme of infected and control animals, respectively. 4. Mr and pI were different for the parasite and hepatic enzyme. 5. The parasite enzyme was less sensitive to the elevation of temperature than hepatic enzyme. 6. The isatin inhibition was a competitive inhibition type for parasite and uncompetitive type for host liver enzyme.

Alkaline Phosphatase↗
PubMed1991

Detection of antibodies against glycolipids of Echinococcus multilocularis metacestodes in sera of patients with alveolar hydatid disease.

Glycosphingolipids extracted from Echinococcus multilocularis metacestodes were tested against sera from patients with alveolar hydatid disease (AHD). The tests were performed first by ELISA then by immunostaining on thin layer chromatography. A binding between the parasite glycolipids and antibodies of AHD human sera was observed by ELISA. The glycolipids related to this binding were specifically parasite neutral glycosphingolipids. No reaction was observed with parasite acid glycolipids nor with neutral glycolipid extracts from human or mongolian gerbil erythrocytes. Comparison between absorbance values of 25 AHD sera and 20 control sera showed significant differences. Similar results were obtained with sera from hydatid cyst patients. Sera from patients with other parasitoses (schistosomiasis, strongyloidosis or paludism) were also tested. The reactive fractions were identified by immunostaining on thin layer chromatography with AHD sera, they were neutral glycosphingolipids containing at least two carbohydrate residues. These results were compared with chromatograms obtained with hydatid cyst human sera and discussed.

Animals↗
PubMed1991

Treatment of experimental alveolar echinococcosis: comparative study of mebendazole, isoprinosine and a mebendazole isoprinosine association.

A comparative biochemical study of the effects of mebendazole and Isoprinosine used separately or associated was conducted in six-month old gerbils infected three months ago by Echinococcus multilocularis metacestodes. Mebendazole treatment induced a decrease of glucose (81%) whereas Isoprinosine increased the glucose uptake in the parasite. The combination of the two drugs led to a decrease of about 40% of the glucose concentration. The specific activities of alkaline and acid phosphatases were also modified. Isoprinosine seemed more effective when used alone than associated with mebendazole with the chosen procedure of treatment.

Acid Phosphatase↗
PubMed1991

Life cycles of Echinococcus multilocularis in relation to human infection.

The cycle of Echinococcus multilocularus in natural and synanthropic hosts was investigated during 10 yr in an endemic focus of alveolar hydatid disease in the Massif Central of France. The natural cycle, involving red foxes, Vulpes vulpes, and voles, Arvicola terrestris, existed immediately surrounding a village in which human cases of alveolar hydatid disease occurred. Both foxes and free-ranging dogs could serve as the source of infection for the human population.

Animals↗
PubMed1990

[Epidemiology and prevention of echinococcosis in France].

Echinococcosis is a cosmopolitan parasitic disease caused by the larvae of two tapeworms: Echinococcus granulosus responsible for unilocular hydatidosis, and Echinococcus multilocularis responsible for alveolar hydatid disease. In both cases man is infected by ingesting eggs of these tapeworms belonging to the genus Cestoda. In France, the only animal that acts as definitive host and transmits the unilocular type of hydatid disease is the dog, while the alveolar type is transmitted by dogs, foxes and cats. Carnivorous pet animals must be taken into account in the prevention of echinococcosis, whether their role is direct or indirect (fouling plants).

Animals↗
PubMed1990

Glycosphingolipids of Echinococcus multilocularis metacestodes.

Neutral and acid glycosphingolipids of Echinococcus multilocularis metacestodes that were obtained after intraperitoneal infection of Meriones unguiculatus have been analyzed by thin layer chromatography. Neutral and acid glycosphingolipids accounted for 95% and 5% of total glycosphingolipids, respectively. 12 different fractions were observed in the neutral glycosphingolipids extracts of the parasite. The most important was a monohexosylceramide fraction accounting for 56.4% of neutral glycosphingolipids. 9 different fractions were detected in gangliosides (acid glycosphingolipids). The fact that these glycosphingolipids were specific to the parasite was established by the analysis of different cell populations of the host. Glycosphingolipids were purified from control and parasite-infected gerbil blood cells as well as from peritoneal exudate cells of healthy gerbils after a non-specific immunostimulation. The chromatograms obtained with these extracts were totally different from the parasite. In addition, parasitosis was found to have no effect on the host blood cell glycosphingolipids.

Animals↗
PubMed1990

In vivo morphological damage induced by a new benzimidazole prodrug in Echinococcus multilocularis metacestodes.

Benzimidazoles are the most widely used compounds in chemotherapy of alveolar hydatid disease (AHD), but long-term administration is required to reach detectable plasma levels. N-Methoxycarbonyl N'-2-nitro 4-trifluoromethyl phenyl thiourea (2) was prepared as a potential prodrug of (5-trifluoromethyl-1H-benzimidazole-2-yl)-carbamic acid methyl ester. Biological effects of 2 were evaluated in gerbils (Meriones unguiculatus) against the causative agent of AHD, Echinococcus multilocularis metacestodes, through a transmission electron microscopy study. Significant morphological damage of tegument and protoscolices occurred after an 18-day treatment. The treatment of AHD by using the prodrug form of the benzimidazole deserves further study.

Animals↗
PubMed1990

Analysis of the monohexosylceramide fraction of Echinococcus multilocularis metacestodes.

Monohexosylceramides of Echinococcus multilocularis metacestodes have been isolated and analyzed by thin-layer chromatography, gas-liquid chromatography and mass spectrometry. 90.9% of the parasite fraction was galactosylceramide; glucosylceramide was present at only 9.1%. The most important fatty acids were normal C16:0 and C26:0 fatty acids. The hydroxylated fatty acids of the ceramide part constituted 20.1% of the total, their major constituents were C18:0 and C26:0. The sphinganine accounted for 70.4% of long-chain bases, phytosphingosine and sphingosine were also detected. The importance of the long chain fatty acids and the presence of sphinganine in the monohexosylceramide fraction were discussed.

Animals↗
PubMed1990

Effects of ethyl N-N-benzyl-methyl-oxamate in Meriones unguiculatus infected with Echinococcus multilocularis metacestodes. Biochemical and ultrastructural observations.

Ethyl N-N-benzyl-methyl-oxamate is a N-substituted derivative of the oxamic acid, well-known as inhibitor of the lactate dehydrogenase activity. The biochemical and ultrastructural effects of this drug in Echinococcus multilocularis metacestodes and the repercussions in the livers of receptive host, Meriones unguiculatus, were investigated. This compound decreased the specific activity of the lactate dehydrogenase in the metacestodes and the host liver by 81 and 86.8%, respectively. This N-methyl compound has shown an important repercussion on the lactate dehydrogenase activity due to its greater lipophilicity and thus allows a better penetration of the molecule. In the host liver, a fall of the alkaline and acid phosphatases activity was observed. The glucose and glycogen concentrations were also decreased. The ultrastructural study provided an alteration of the tegument of the metacestodes and damages of the muscular system. The parenchyma was disorganized. In conclusion, these biochemical and ultrastructural data obtained with ethyl-N-N-benzyl-methyl oxamate in E. multilocularis metacestodes show clearly the importance of the lactate dehydrogenase activity in the metacestodes.

Acid Phosphatase↗