[Role of single-therapy diazepam in severe poisonings by chloroquine].
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Adolescent↗
Biomedical subjects
J Kempf
Publications and source records attributed to J Kempf.
Preparation and characterization of monoclonal antibodies against beta-bungarotoxin and its A- and B-chains.
Splenocytes from Balb/c mice immunized with beta-bungarotoxin, a protein neurotoxin that exhibits phospholipase A2 activity, were fused with SP2/0 murine myeloma cells. Eighty-seven stable hybridoma cell lines were established which secrete monoclonal antibodies of the subclass IgG1 and K light chain and react with intact neurotoxin. Some antibodies were further analyzed. These recognize at least two immuno-dominant regions located on the A- and B-chains of the toxin, and the native toxin but show no crossreactivity with a protein homologous to chain A (porcine pancreas phospholipase A2) nor to chain B (toxin 1 from Dendroaspis polylepis). Two monoclonal antibodies inhibit phospholipase A2 activity of the neurotoxin but only one partially neutralizes its biological activity when injected together with the toxin, delaying the time of death.
Animals↗
Influence of mouse genotype on responses on central neurotransmitters to long-term alcohol exposure in striatum and hippocampus.
A striking strain dependency in response of central neuromediators (dopamine, serotonin, acetylcholine activities and somatostatin) to various periods of alcohol treatment has been noted in striatum and hippocampus in mice. For biogenic amines the C57Bl strain loses tolerance to prolonged alcohol injury earlier than the Balb/c strain. At the opposite the Balb/c strain exhibits a remarkable long lasting tolerance for cholinergic activity. The unequal capacity to adapt, also appears to depend on the nervous structure and the neurotransmitter considered. Such discrepancies may underly differences in behavioral changes observed in alcoholics.
Animals↗
Genotypic differences in age and chronic alcohol exposure effects on somatostatin levels in hippocampus and striatum in mice.
Somatostatin contents of striatum, hippocampus, and pons medulla have been followed in two inbred strains of mice (C57B1/6J and Balb/cJ) with aging and long term alcohol exposure (over a 25 month period of intoxication). Marked strain dependent differences in basic levels of somatostatin and genotypic variations in reactivity of this neuropeptide to aging processes and chronic alcohol exposure were demonstrated. The Balb/c strain exhibits a significant age dependent decrease in striatal and hippocampal somatostatin levels whereas the C57B1 mice remain unchanged until the 27 month. Moreover, only the Balb/c strain reacts to chronic alcohol exposure, showing a significant increase in somatostatin levels in those structures affected by the aging process. Such genotypic differences may be involved in man in specific pathologies in aged individuals and in alcohol induced behavioral alterations in alcoholics.
Aging↗
Neutralization of alpha-bungarotoxin by monoclonal antibodies.
We have produced monoclonal antibodies against alpha-bungarotoxin from Bungarus multicinctus, and controls were performed for their specificity and monoclonal character. The antibodies protected mice against the toxic effect of alpha-bungarotoxin for a few hours to six days, depending upon the chosen antibody (in comparison to a survival time of 79 min for the standard toxin dose). Antibodies can be grouped in several sets according to their duration of protection.
Animals↗
Expression of cholinergic markers in the developing chick embryo spinal cord.
The expression of cholinergic neurotransmission in the developing spinal cord was followed with pre- and postsynaptic cholinergic markers and histoautoradiographic determinations of cholinergic receptors and ultrastructural studies. Two distinct steps in the development of cholinergic markers were evident. The first step of cholinergic expression occurs early in development and its characterized by a sudden and large increase in choline acetyltransferase activity, whereas the high affinity choline uptake mechanism remains undetectable and few muscarinic receptors are detectable. This phenomenon possibly reflects the expression of high choline acetyltransferase gene activity in developing neurons which are still not synaptically connected. The second step is also characterized by a sharp rise of choline acetyltransferase activity. This rise parallels an active development of high affinity choline uptake and big increase in both number and density of muscarinic receptors. Also nicotine receptors increase, as revealed by histoautoradiography. Specific morphogenetic events, such as the increase of synaptic junctions with postsynaptic thickenings and numerous presynaptic clear vesicles, occur at the same time. Such interactions may contribute to the full maturity of cholinergic neurotransmission of the spinal cord.
Acetylcholinesterase↗
Passive avoidance behavior in mice: interaction between age and genotype.
BALB/c (BALB) and C57BL/6 (C57) mice were tested in a passive avoidance apparatus at different ages (6, 12 and 24 months). Results showed a clear-cut retention decrease only in 24 month old BALB mice in comparison with younger animals. No significant age effect was evident in C57 mice.
Aging↗
Correlation of DNA repair synthesis with ageing in mice, evidenced by quantitative autoradiography.
Fibroblasts from C57B1/6 female mice of different age have been treated with short-wave ultraviolet light. The amount of unscheduled DNA synthesis in the fibroblasts, determined by quantitative histoautoradiography, decreases with the donor's age. This result is discussed with regard to an increase in nuclear area and modifications of cell population dynamics with age. Moreover, differences between individuals of the same age group with regards to unscheduled DNA synthesis have been observed.
Aging↗
Genotypic variation in the dopaminergic inhibitory control of striatal and hippocampal cholinergic activity in mice.
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Acetylcholine↗
Role of calmodulin in the effect of guanyl nucleotides on rat hippocampal adenylate cyclase: involvement of adenosine and opiates.
The adenylate cyclase activity of rat hippocampal plasma membranes can be stimulated by vasoactive intestinal polypeptide (VIP). Low concentrations (10(-9) to 19(-7) M) of 5'-guanylyl-imido diphosphate (GppNHp) evoke a transient inhibition of the enzyme, which is followed by stimulation with increasing GppNHp concentrations (10(-6) to 10(-4) M). Inclusion of Inclusion of ethyleneglycol-bis-(beta-aminoethylether)-N,N'-tetraacetic acid (EGTA) during incubation abolishes the GppNHp inhibition while preserving GppNHp activation. The stimulation induced by GppNHp is amplified by VIP, but the inhibition is unaffected. Adenosine analogs and opiates are inhibitory ligands in the presence of GTP, and their effects can be reversed by the appropriate receptor antagonists, 3-isobutyl-1-methylxanthine and naloxone. Treatment of membranes with trypsin abolishes the GppNHp-induced inhibition without affecting the GppNHp stimulation. The inhibition induced by GppNHp is also abolished by EGTA treatment followed by washing, which coincides with a reduction in the adenosine- and opiate-mediated, GTP-dependent inhibition. The GppNHp inhibition can be restored in EGTA-treated but not in trypsin-treated membranes by addition of calcium-calmodulin but not by Ca2+ or Mg2+. Calcium-calmodulin-depleted membranes lack calcium stimulation as well as GppNHp-induced inhibition, whereas untreated membranes and calcium-calmodulin-depleted membranes plus exogenous calcium-calmodulin showed calcium stimulation and GppNHp inhibition. These results suggest that calmodulin is involved in both Ca2+ stimulation and guanine nucleotide-mediated inhibition of rat hippocampal adenylate cyclase.
Adenosine↗
Microsomal cAMP-independent histone H1 kinase activity in plasmacytoma, Morris hepatoma and normal liver.
A protein kinase activity with high specificity for histone H1 was isolated from mouse plasmacytoma, Morris hepatoma and normal mouse liver and compared by ion exchange chromatography after DEAE-cellulose, hydroxylapatite and Sephadex G-200 chromatography. This cAMP-independent histone H1 kinase is not affected by the heat-stable cAMP-dependent protein kinase inhibitor. It has the following particular properties: it prefers GTP to ATP as substrate and was found to be present with a great activity only in neoplastic tissues. No phosphatase activity was detected in the partially purified histone H1 kinase fraction from normal and neoplastic cells. These results suggest either an increase amount of histone H1 kinase and/or of its activator in neoplastic cells, or the presence of a strong inhibitor in normal cells. This histone H1 kinase appears to be analogous to the chromatin bound kinase which phosphorylates histone H1 at the NH2 and COOH terminal regions. We might suggest an implication of this kinase in the regulation of cell division.
Adenosine Triphosphate↗
Autoradiographic grain counting by fully automated image analysis.
A method for automated quantitative analysis of single label microautoradiographs applied to DNA repair synthesis is proposed. It uses image analysis of the microscopic field by a Leitz TAS and allows an automated selection of the nuclei to be analysed. The use of a grey level gradient algorithm provides a relatively large independence from external variables such as staining intensity, nuclei density in the field, stability of illumination etc. Random choice of the microscopic field by the computer directed stage displacement and automatic focusing ensures a high degree of objectivity and independence from human intervention. The coefficient of correlation between the automatic and the visual grain count is 0.97 in the range of visually countable grain densities, while the precision of measurement is about 10%. The speed of measurement is satisfactory (40 to 60 s for the analyse of a microscopic field) taking in account that only occasional supervision is needed.
Animals↗
Phosphorylated proteins in the passage from free mRNP to polysomes in mice plasmacytoma cells.
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Animals↗
In vitro activation of DNA polymerase-alpha by a protein kinase in chick embryo.
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Animals↗
Protein kinases and their protein substrates in free messenger ribonucleoprotein particles and polysomes from mouse plasmacytoma cells.
In free messenger ribonucleoprotein particles (mRNP) and polysomes from plasmacytoma cells, a phosphorylated protein/protein kinase system has been characterized by a combination of oligo(dT)-cellulose chromatography and CsCl isopycnic gradient centrifugation. The presence phosphorylated in vivo has been detected in both types of particles. Endogenous protein phosphorylation occurs in vitro by particle-associated cAMP-independent protein kinase(s) using [gamma-32P]ATP and [gamma-32P]GTP. These kinases are sensitive to hemin action. Analysis of mRNP proteins by gel electrophoresis and autoradiography showed strong analogies between the phosphorylation patterns obtained in vivo and in vitro, suggesting a substrate specificity for the associated enzymes. The phosphorylated proteins have been compared to initiation factors and ribosomal proteins. We have partially purified the cAMP-independent protein kinase activities responsible for the endogenous phosphorylation in free mRNP and polysomes; two activities were identified in free mRNP whereas three activities were found to be associated with polysomes.
Adenosine Triphosphate↗
Cyclic nucleotides and calcium in human lymphocytes induced to divide.
Intracellular concentrations of cyclic adenosine 3'-5' monophosphate (cAMP) and cyclic guanosine 3'-5' monophosphate (cGMP) were measured in human lymphocytes induced to divide by the addition of lectins, 12-O-tetra-decanoylphorbol-13-acetate (TPA) and the calcium ionophore A 23187. cGMP levels rose within minutes without concomitant alterations in cAMP concentration. The cAMP and cGMP levels rose during the prereplicative and replicative phases respectively. Under calcium depleting conditions, both the fluctuations in cyclic nucleotide levels and the increase in [3H[ thymidine incorporation into DNA were abolished, suggesting a role for calcium ions in the regulation of lymphocyte proliferation.
Calcium↗
A new chromatographic method using immobilized acriflavin for measuring cyclic AMP in cells prelabeled with radioactive adenine.
A method using the principle of charge-transfer chromatography has been developed for the determination of cyclic AMP levels in intact prelabeled cells. The ATP pool was prelabeled by incubating the cells in the presence of radioactive adenine. The cyclic AMP formed from ATP was extracted with HC10(4) and separated from adenine and other adenosine-related nucleotides by chromatography on acriflavin-Sephadex G-25. This method provides a rapid and sensitive isolation of cyclic AMP with high recovery (95-100%) and low blnks. Further, no contamination of the cyclic AMP fractions was found by either adenine or adenosine nucleotides such as ATP, ADP or AMP. This procedure is applicable to a variety of cell or tissue systems.
Acridines↗
Resolution and general properties of different types of ribosomal protein kinases in mouse plasmocytoma.
Three different types of protein kinases (ATP: protein phosphotransferase, EC 2.7.1.37) were isolated and partially purified from a mouse plasmacytoma microsomal KCl wash fraction, then chromatographed on DEAE cellulose and phosphocellulose. The three protein kinase activities designated by protein kinase I, II and III were characterized with respect to their capacity to utilize [gamma-32P]ATP and [gamma-32P]GTP, to interact with cyclic AMP, stimulation by cyclic AMP, substrate specificity and sedimentation behaviour on glycerol gradient centrifugation. Protein kinase I was found to be cyclic AMP dependent and preferentially phosphorylated histones. Protein kinase II and III were insensitive to cyclic AMP, protein kinase II preferentially phosphorylated histones and the protein(s) of a ribosomal KCl wash fraction eluted from DEAE cellulose between 0.2 and 0.35 M KCl and termed "PPx". Protein kinase III phosphorylated casein and ribosomal proteins to a great extent. Studies with glycerol density gradient centrifugation indicated that protein kinase I sediments as a component of about 4.4 S, protein kinase II of 4.3 S and protein kinase III of 3 S. Chromatography on phosphocellulose of the protein kinases isolated from purified free polysomes showed the same type of protein kinases as those from microsomes. So it appears unlikely that protein kinase I and II were contaminants from the cytosol.
Animals↗