Search

For the diagnosis of Clostridium difficile infection (CDI), it is necessary to obtain microbiological evidence of toxigenic C. difficile with a compatible clinical picture (diarrhoea or ileus). Two gold standards exist: cell culture cytotoxicity neutralization assay (specific, but less sensitive than previously acknowledged) and toxigenic culture (very sensitive but less specific because it also detects asymptomatic colonization). These gold standards are not used routinely because at least 2 or 3 days are needed to get a definitive result. Enzyme immunoassays (EIA) are used by most of the French laboratories for the detection of toxins A and B: they provide a quick answer but their sensitivity is insufficient (only 50%). Molecular assays (targeting tcdA or tcdB genes) and glutamate dehydrogenase (GDH) EIA represent an attractive alternative because their high sensitivity (>85%) allow to definitely rule out CDI in the case of a negative result. The presence of GDH is not specific of toxigenic C. difficile: positive results must be confirmed by another method. In the event of a positive molecular assay without toxin presence assessed by EIA or cytotoxicity assay, other causes of diarrhoea should be ruled out before a definitive diagnosis of CDI can be made.

Tomato seedlings grown on nitric medium and treated with various cadmium concentrations (0 to 50 microM) were used. Results obtained show that cadmium remains predominantly located in the roots, which then seem to play the role of trap-organs. Increasing cadmium concentration in the medium leads particularly to a decrease in NO3- accumulation, together with a decrease in the activity of glutamine synthetase and in the quantity of plastidic isoform ARNm (GS2), and, on the contrary, to an increase of the cytosolic isoform ARNm (GS1). On the other hand, stimulations were observed for NADH-dependent glutamate synthase, NADH-dependent glutamate dehydrogenase, ARNm quantity of this enzyme, ammonium accumulation, and protease activity. In parallel, stimulations were observed for NAD+ and NADP+-dependent malate dehydrogenase and NADP+-dependent isocitrate dehydrogenase. These results were discussed in relation to the hypothesis attributing to the dehydrogenase enzymes (GDH, MDH, ICDH) an important role in the plant defence processes against cadmium-induced stresses.

In order to better understand the effects of heavy metals on the growth of plants, we decided to perform recovering experiments by following both chemical and physiological parameters in cadmium pre-stressed tomato seedlings after cadmium had been removed from the nutrient solution. The work shows that cadmium suppression results in resumption of growth activity. The biomass of leaves and stems rose steadily. The increase in root biomass exceeded those of leaves and stems. At the same time, nitrate content was increased to reach the level obtained with unstressed controls. In all the organs studied, the activities of the enzymes involved in the anabolic nitrogen primary assimilation pathways (nitrate reductase (NR), nitrite reductase (NiR) and glutamine synthetase (GS) soared after that cadmium had been removed. While NAD(+)-dependent glutamate dehydrogenase (GDH-NAD+) activity also rose progressively during the recovering time, the cognate NADH-dependent glutamate dehydrogenase (GDH-NADH) activity decreased. This result allows us to propose that the ammonia produced by the stress-induced protein catabolism is detoxified and re-assimilated by the GDH-NADH isoenzyme. On the basis of these results, we will discuss the ability of the plant to dilute the effects of pollutants during the recovering period. An important outcome of this work is that a transient contamination of the culture medium by pollutants is not necessarily followed by a significant depreciation in product yield or quality.

Summary Pathways of inorganic nitrogen assimilation are very often different in higher plants and fungi and this raises the intriguing problem of their coexistence and interactions in ectomycorrhizas. Results based on amino acid accumulation, enzyme assays, electrophoretic patterns on gels and immunogold labelling have consistently shown that beech ectomycorrhizas are similar to higher plants in that glutamine synthetase (GS) and glutamate synthase (GOGAT) are operative, while fungal glutamate dehydrogenese (NADP-GDH) is strongly repressed. By contrast, in spruce and Douglas-fir ectomycorrhizas, fungal NADP-GDH was found to be involved in ammonium assimilation, jointly with the GS enzyme. Enzyme repression seems to be due to the host plant but is moderated by the structure of the ectomycorrhizas and especially by the degree of association of the fungus with root tissues, as found in Eucalypt ectomycorrhizas. In all the ectomycorrhizas investigated, fungal aspartate aminotransferase (AAT) was found to be r...

Three methods of preservation of the in situ temporarily ischaemic kidney were compared in dogs. The study was carried out in 24 dogs, divided in 4 groups. Each group included 4 dogs in which the ischaemic time was 60 minutes, and 3 dogs in which the ischaemic time was 90 minutes. The experimental animals of the first group served as controls (warm ischaemia); in the second group renal hypothermia was accomplished by an arterial infusion of Collins' solution at 4 degrees C; in the third group preservation of the kidney was attempted only by an arterial infusion of inosine (90-120 mg/kg); finally in the fourth group, the infusion of Collins' solution was combined with infusion of inosine (800-1 000 mg/l Collins' solution). The assessment of the damage of the ischaemic kidney was made by histo-enzymological analysis of renal tissue specimens received from each animal just before initiation of the ischaemia and on the 21st post-operative days. The enzymes examined in this analysis were: Alkaline Phosphatase, ATP-ase, Glutamate Dehydrogenase, Glucose-6-phosphatase, Hydroxybutyrate Dehydrogenase and gamma-GT. These studies have shown that the ischaemic kidney is best preserved by the arterial infusion of Collins' solution with simultaneous infusion of inosine.

A histochemical study on Lacerta lepida cerebral cortex glutamic dehydrogenase activity (GLD) was reported in this paper. The GLD activity is revealed in neurons and fibers of cerebral cortex. The regions M1 and M2 were differentiated with regard to enzymatical activity. The M2 neurons are morphologically and histochemically similar to D1 neurons but not to M1 neurons.

The glutamate dehydrogenase and glutamine synthetase activities of an obligate halophyte, Suaeda maritima var. macrocarpa and a glycophyte. Phaseolus vulgaris are compared in function of salinity (increasing concentrations of NaCl) of the culturing solution. In culture, addition of NaCl stimulates glutamine synthetase activity and lowers glutamine dehydrogenase activity in the aerial organs and in the roots of Suaeda as opposed to what is observed in the glycophyte. Hence the obligatory halophily of Suaeda is related to an increase of the glutamine synthetase activity in a sal-trich medium corresponding to the stimulation of nitrate reductase and proteogenesis.

Three groups of twelve cows were chosen after slaughter on the basis of their state of liver damage. First group of cows was normal (no visible hepatic lesion : N group); second group (CD group) had cholangitis lesions related to Fasciola hepatica; and the last group (AN) had severe liver damages. Histopathologic examinations, various metabolic determinations in plasma and an immunologic detection of Fasciola hepatica were performed on hepatic tissue or blood samples. Results showed that gamma-GT, GLDH, albumin, globulins and total protein levels in plasma were significatively different between N group and CD or AN groups. Comparison between CD group and AN group showed that GLDH activities were significatively higher and albumin concentrations significatively lower in AN group than in CD group. Immunological test showed that Fasciola hepatica was the main cause of the liver lesions. It was concluded that an hepatic blood profile should include gamma-GT, GLDH and albumin determinations and a Fasciola hepatica serological test. Other hepatic tests are presented to complete the hepatic profile.

Many different serum biochemical tests can help in the diagnosis of liver disturbances in ruminants. The best tests for hepato-cellular damage are the measurement of enzymes such as glutamate dehydrogenase, sorbitol dehydrogenase and, if available, arginase or ornithine carbamoyl transferase. Disturbances of biliary function can be investigated through the measurement of so-called "cholestasis enzyme markers" such as gammaglutamyl transferase or alkaline phosphatases; bilirubin and bile salts can also be helpful. Liver insufficiency can be approached through the measurement of serum albumin, fibrinogen and coagulation tests whereas inflammative and inductive processes are difficult to investigate. Moreover, liver clearances (bromosulfonephtalein or indocyanine green) can provide useful data about whole liver function.

An automatic continuous flow method is described for assay of plasmatic and urinary urea after hydrolysis by urease followed by NH4 assay with glutamic deshydrogenase in the same working solution. Precision and accuracy, comparison with chemical diacetylmonoxim method are studied. The interaction of endogenous NH4, the cost of the method are calculated.

Measuring the activity of certain serum enzymes is of considerable interest in the diagnosis of hepatic or biliary diseases, even in the absence of jaundice. The battery of tests required is at present limited to transaminases for cytolysis, alkaline phosphatase for cholestasis, and gamma-glutamyl-transpeptidase for chronic alcoholism, carcinoma of the liver and obstruction of the common bile duct. The enzymatic profile thus obtained complements the clinical findings and often provides decisive arguments in favour of a diagnosis, thereby avoiding invasive radiological and instrumental explorations.

The levels of ornithine carbamyl transferase, acid phosphatase, alkaline phosphatase, leucine amino peptidase, creatine kinase, amylase, glutamic oxalacetic transaminase, glutamic pyruvic transaminase, lactate deshydrogenase, hydroxybutyrate deshydrogenase, glutamate deshydrogenase and malate deshydrogenase were determined in the plasma of Rainbow Trout and Tench submitted to water temperature increases. In the Rainbow Trout a thermal shock from 12 to 21 degrees, increases activities of some enzymes while temperature increase up to pre-mortem stage causes very important changes in enzymatic levels. In the Tench a thermal shock from 12 to 28 degrees causes more changes of enzymatic activities than a shock from 12 to 25 degrees. In Tench acclimated to 25 degrees, various enzyme levels are increased in comparison with 12 degrees control animals. A high potassium level in water causes complex changes in enzyme levels. The most sensitive enzymes to thermal disturbance are GOT and GPt transaminases which increase whatever the aggression form, amylase when thermal disturbance is moderate, alkaline phosphatase and malate deshydrogenase in case of strong thermal stress. The study of these enzymes is recommended for watching the state of fishes living in artificially heated waters.

384 hospitalized patients of both sexes were classified into drinkers and non-drinkers according to clinical criteria. On admission, we measured four blood parameters : glutamate dehydrogenase, gamma glutamyl transferase, aspartate aminotransferase and the mean corpuscular volume. the discriminating power of these laboratory parameters was evaluated by descriptive statistical tests and by the determination of their positive and negative predictive value. Glutamate dehydrogenase appears to present a sensitivity almost equivalent to that of gamma glutamyl transferase and a better specificity : this results in a more positive predictive value. The two other laboratory parameters are less discriminating.

Rainbow trout acclimatized to 9 degrees C were subjected to a temperature increase (up to 17 degrees C) for 16 hrs. During the period of acclimatization to 17 degrees C, we studied blood ammonia and urea and the hepatic activity of glutamate dehydrogenase, glutaminase, uricase and arginase. The daily mean rates of blood ammonia and urea did not differ significantly at 9 and 17 degrees C. However, the pattern of these two parameters during the circadian cycle was not the same at 9 degrees C as after 23 days at 17 degrees C. The enzymatic activities rose after one day at 17 degrees C and remained unchanged, except for arginase which showed perfect thermal compensation. During the circadian cycle, there was some similitude between glutaminase activity and blood ammonia at 9 degrees C and after 23 days at 17 degrees C, as well as between arginase activity and blood urea.

In this work we research into the GDH location of the spinal cord, in the medullar oblongata and in the central cerebellar nuclei of the rat, cat, dog, chicken, lizard (Lacerta lepida), and Toad (Bufo calamita). The GDH is located at the cytoplasm and at the neuronal prolongations, at oligodendrocytes cells, at Lecerta ependimary glial cells, and at the capillary walls.

The polymorphism of glutamate, lactate and malate dehydrogenases, of acid phosphatase and of esterases of 27 strains of Providencia alcalifaciens, 35 strains of P. stuartii and 17 strains of P. rustigianii was investigated by conventional electrophoresis in polyacrylamide agarose gel and by isoelectric focusing in thin-layer polyacrylamide gel. For each enzyme analysed, the three species were characterized by a distinct electrophoretic pattern. The number of allozymes detected by conventional electrophoresis was greater than that detected by isoelectric focusing. The use of these two techniques in parallel led to improved detection of polymorphism of esterase alpha beta from P. alcalifaciens. A two-dimensional profile obtained by plotting isoelectric points against electrophoretic mobilities for malate dehydrogenase, acid phosphatase and beta-A esterase showed a molecular relationship between the diverse allozymes and demonstrated their taxonomic values. Polymorphism varied considerably according to the enzyme and species analysed and was correlated with DNA heterogeneity. The strains of P. alcalifaciens exhibited the greatest enzyme polymorphism and were classified into two main zymotypes reflecting genetic divergence within this species, whereas the strains of P. stuartii were electrophoretically less variable.

Previous anatomochemical and experimental investigations had resulted in the histochemical characterisation of the epileptogenic focus by the presence of "activated astrocytes"; cortical reactive astrocytes acquiring an intense activity of sundry dehydrogenases (DH) and becoming visible in spite of the positivity of the neuropil, and stopping at the amylose step in the synthesis of glycogen. This activation exists from the first electrical sings of epilepsy and even preceeds them in the case of glucose-6-phosphate DH. The present study deals with the fate of activated astrocytes after the disappearance of electrical signs of the epileptogenic focus produced by implantation of a cobalt powder-gelatin pellet into the cerebral cortex of the rat. After extinction of the focus, high activity of DH persists in astrocytes only in the immediate vicinity of the glial scar surrounding the implant. Later, among the DH investigated only glutamate and specially glucose-6-phosphate DH maintain an activity intense enough to reveal these cells on the background of the neuropil. These results point to a progressive return to a normal metabolism of astrocytes after the disappearance of the electrical signs of epilepsy by way of steps similar to those preceeding these signs.

Investigation of astrocytes in the pyramidal tract of the rat 2 to 100 days after a lesion of the motor cortex indicates that the glial reaction, with increase in size of astrocytes and in affinity for Cajal's gold-sublimate, begins at the lesion and extends to the distal segments of the spinal cord. But this reaction recedes and disappears in lumbar and dorsal cord about 70 days after the operation. It persists in the cervical cord and in the brain. On the other hand, a characteristic increase in activity of glutamate andglucose-6-phosphate dehydrogenases is restricted to the vicinity of the lesion and does not even encroach upon the posterior limb of the internal capsule.

Many different serum biochemical tests can help in the diagnosis of liver disturbances in ruminants. The best tests for hepato-cellular damage are the measurement of enzymes such as glutamate dehydrogenase, sorbitol dehydrogenase and, if available, arginase or ornithine carbamoyl transferase. Disturbances of biliary function can be investigated through the measurement of so-called "cholestasis enzyme markers" such as gammaglutamyl transferase or alkaline phosphatases; bilirubin and bile salts can also be helpful. Liver insufficiency can be approached through the measurement of serum albumin, fibrinogen and coagulation tests whereas inflammative and inductive processes are difficult to investigate. Moreover, liver clearances (bromosulfonephtalein or indocyanine green) can provide useful data about whole liver function.

This paper deals with the study of biochemical activity, by means of correspondence analysis, of about fifty original molecules of di- and triphenylethylene structures. The pharmacological experiments were made on glutamate deshydrogenase and prostaglandine synthetase. A typology of several molecular groups is established and the effects of various substituents are specified.

An automated continuous flow method is described for the assay of plasmatic urea after hydrolysis by urease followed by NH+4 assay with glutamic-deshydrogenase. Precision and accuracy, comparison with chimical diacetyl-monoxim method are studied. The interaction of endogenous NH+4, the cost of the method are calculated.

The study by bistochemical method of some dehydrogenases in 74 glioblastoma multiforma permits to distinguish several metabolic groups. But if particular attention is payed to the activity of glutamate dehydrogenase, it is noted to be observed only in the small, dedifferentiated cells when the survival postoperative time was more than twelve months. As it is known that an operated glioblastoma does not survive more than one year, except if it is a secondary glioblastoma, it is concluded that the existence of this enzyme in those little cells permits to distinguish secondary from primitive glioblastoma.

Esterases, acid phosphatase and glutamate and malate dehydrogenases of 11 strains of Escherichia hermannii were analysed by horizontal electrophoresis in polyacrylamide agarose gel. Seven esterase bands were defined by their range of activity on synthetic substrates and their sensitivity or resistance to di-isopropyl fluorophosphate. These bands were different in activity and in mobility from those produced by E. coli strains. On the basis of variations in mobility of glutamate and malate dehydrogenases and in the number and mobility of esterases, the strains were divided into 3 zymotypes.

Three, four, and one horses were respectively infected with 100, 1,000, and 5,000 metacercariae of Fasciola hepatica. Six of them were reinfected 38 weeks later with 1,000 metacercariae each. Specific antibodies assayed by counter-electrophoresis, passive hemagglutination and ELISA tests appeared three to six weeks post-infection and peaked 10 to 17 weeks post-infection. Horses infected by 1,000 metacercariae and more showed 17.6% of positive samples by counter-electrophoresis, 49.2% by ELISA, and 75.6% by passive hemagglutination. Plasma glutamate dehydrogenase and gamma-glutamyltransferase levels increased significantly 3 to 5 months post-infection in the most infected animals. Eggs of Fasciola hepatica were only observed in 2 of the 8 horses, 14 and 15 weeks post-infection. This last observation indicates the limits of fecal examination in the diagnosis of fascioliasis in horses.