Search PubMed⌕ Search

Biomedical subjects

P Mandel

Publications and source records attributed to P Mandel.

At least 379 records · Page 21Linked to original sources
PubMed1978

[Effect of propyl-2-pentene-2-oic acid on GABA levels in different regions of mouse brain].

An elevation in cerebral GABA level (65%) is observed after administration of an anticonvulsant, sodium propyl 2-pentene-2 oate, a branched chain fatty acid, comformationally restricted GABA analogue, competitive inhibitor of GABA-T in regard to GABA. The concentration of GABA increases in some regions i.e. substantia nigra, frontal and temporal cortex, cerebellum and olfactory bulbs. The GABA level remains unchanged in caudate nucleus, hippocampus and occipital cortex. Results are discussed comparatively to the effect of sodium n-dipropylacetate.

Animals↗
PubMed1978

[Effect of sodium n-dipropylacetate (sodium valproate) on GABA level of neuronal and glial cells in culture].

The effect of sodium n dipropylacetate (nDPA), a competitive GABA-T inhibitor with respect to GABA, has been investigated on glial and neuronal cellular GABA level. After 1 to 4 days incubation with nDPA in the culture medium, a decrease of GABA level in M5 neuroblastoma clonal cell lines and no modification of GABA level in C6 astrocytoma cells has been observed. The combined addition of nDPA 4 micrometer with dibutyryl cyclic AMP (1 mM) to the culture medium induces the same decrease in GABA level in C6 astrocytoma cells as the addition of DB-c-AMP alone. After shorter incubation time with nDPA (5-150 min), we observed a decreased GABA level in C6 astrocytoma glial cells.

Animals↗
PubMed1978

[Experience in application of electronic data processing in routine medical microbiology (author's transl)].

Experiences in a two years application of electronic data processing in medical routine microbiology are reported. Optical mark reader forms serve as request forms as well as workprotocol. On the left two thirds of these forms (Fig. 1 and 2) the patients data including clinical statements, and the kind of specimen to be investigated (sputum, smear etc.) as well as results not essential for the printout of laboratory reports are filled in. On the right third of the optical mark reader form, in which area the Bell & Howell document reader can read pencil marks, the patients identification number, the tests requested and all results are marked right at the work bench. As shown in the flow diagram (Fig. 3) after completion of the investigation the date on the mark reader forms are read mechanically and the test results are printed (Fig. 5) by means of the computer. In addition, the data processing system, which proved to be very flexible, performs all necessary types of administrative work as filing of laboratory data in a coded form on cards for permanent storage (Fig. 7) statistics and the printout of bills (Fig. 6). The processing of routine microbiology date is achieved by a Siemens DVA 404/3 (64 kbt) connected for magnetic disc device (2993 Mio bytes), and a line printer (60,000 lines per hour) and dialog display monitors, which are used simultaneously for the on line and off line handling of all the data in clinical chemistry-, serology- and hematology-departments of the same institute.

Computers↗
PubMed1977

Effects of deoxycholate and phospholipase A2 on choline and ethanolamine phosphotransferases of chicken brain microsomes.

Ethanolamine phosphotransferase (EC 2.7.8.1) and choline phosphotransferase (EC 2.7.8.2) activities were assayed in fresh microsomes from adult chicken brains with either diacylglycerols or alkylacylglycerols. Pretreatment of microsomes with 1.25 mM sodium deoxycholate, a concentration less than the critical micelle concentration, produced a slight inhibition of choline phosphotransferase activity. A deoxycholate concentration (5.0 mM) greater than the critical micelle concentration (3.0 mM) decreased the choline phosphotransferase activity by more than 70% but had no effect on ethanolamine phosphotransferase activity. Inclusion of 1.25 mM deoxycholate in the assay medium decreased choline phosphotransferase activity 35% but increased ethanolamine phosphotransferase activity 50%. The deoxycholate appeared to inactive the choline phosphotransferase. Phospholipase A2 (Vipera russelli) treatments of microsomes removed phosphoglycerides and decreased both phosphotransferase activities to a similar extent. Decreased activities are probably due to disruption of the membrane structure. Choline and ethanolamine phosphotransferase activities are apparently in different enzymes which lack specificity for the type of diglyceride. Thus, the systematic names should include 1,2-diradyl-sn-glycerol instead of 1,2-diacyl-sn-glycerol.

Animals↗
PubMed1977

[Purification of calf thymus adenosine diphosphate ribose polymerase].

Calf thymus poly ADPR polymerase has been purified to electrophoretic homogenity. The enzyme has a molecular weight of 120,000 +/- 10,000 dalton. The substrate affinity is very high (apparent Km 82.5 micrometer). The presence of exogenous DNA does not appear to be a requisite for enzymatic activity of the purified enzyme.

Animals↗
PubMed1977

Regional acetylcholine turnover rates in the brains of three inbred strains of mice: correlation with some interstrain behavioural differences.

The hypothesis that the genetically determined behavioural differences which exist between the inbred mouse strains Balb/c, DBA/2 and C57Bl/6 may be related to differences in acetylcholine metabolism in certain regions of the brain has been tested. In vivo ACh turnover rates have been measured in three regions (hippocampus, caudate nucleus and frontal-parietal cortex) of the brains of each strain by following the rate of formation of labelled ACh, in these regions, after a pulse intravenous injection of a tracer dose of 3H labelled choline. Focused microwave procedures were used for the rapid fixation of brain tissue and Ch and ACh radioactivities were determined following their electrophoretic separation. Steady-state concentrations of Ch and ACh were measured by a sensitive radio-enzymatic method. Significant interstrain differences in ACh turnover rates are reported for each of the brain regions studied with the order of metabolic activity being Balb/c greater than DBA/2 greater than C57 Bl/6 in each case. These results are interpreted as being in agreement with previous reports on correlations between learning ability or locomotor activity and regional activities of choline acetyltransferase in the brains of these inbred strains. The correlations between the in vivo ACh turnover rates and (1) interstrain differences in behavioural measures and (2) regional choline acetyltransferase activities are discussed.

Acetylcholine↗
PubMed1977

Gangliosides and phospholipids of the membranes from bovine adrenal medullary chromaffin granules.

The lipid and ganglioside compositions of membranes of chromaffin granules isolated from bovine adrenal medulla have been investigated. The detailed lipid analysis revealed the presence of high levels of lysophosphatidylcholine, in agreement with previous studies, but also of sphingomyelin and plasmalogens. From these membranes, gangliosides have been extracted and separated by thin-layer chromatography and analysed. 95% of the total recovered gangliosides were hematosides (GM3), which migrated as three major species. Sugar analyses have been performed, as well as the fatty acid compositions. The three hematoside gangliosides appeared to differ on the basis of their fatty acid composition. Compared with the brain, chromaffin granule membranes showed a simple ganglioside composition, thus offering a good model for the study of the metabolism and the role of gangliosides. The simple ganglioside composition of chromaffin granule membranes has allowed us to state that there are 60 mol phospholipid and 30 mol cholesterol per mol ganglioside.

Adrenal Medulla↗
PubMed1977

[Purification of the glutamate decarboxylase from human brain].

A method of purifying the glutamate decarboxylase from human brain is described. The enzyme was purified 8 000 fold in regard to the initial homogenate and appears homogenous by electrophoresis, both in denaturing and non-denaturing conditions. The molecular weight of the native enzyme and its subunits indicate that GAD from human brain is formed by two similar if non identical polypeptide chains. The Km for glutamate and pyridoxal phosphate found for the human enzyme, respectively 1,2.10(-3) M and 0,13.10(-6) M, are close to the Km found for the Mouse enzyme.

Brain↗