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Biomedical subjects

E Toth

Publications and source records attributed to E Toth.

At least 55 records · Page 3Linked to original sources

Antagonism of phencyclidine-induced hyperactivity by glycine in mice.

We tested the effect of glycine on phencyclidine (PCP)-induced hyperactivity in mice. Glycine antagonized the locomotor stimulating effect of PCP. Correlation was found between the degree of antagonistic effect and the size of the increase in glycine in the brain. The antagonism is not due to changes in uptake, since the elevation of glycine in plasma and brain had no effect on the cerebral uptake of PCP. This pharmacological action of glycine appears to be a central effect, but some peripheral effect can not be excluded. Since glycine is not toxic at levels needed for PCP antagonism, it could be considered for ameliorating PCP psychosis. The locomotor stimulating effect of PCP is strain dependent in mouse. Some strains are responsive, such as BALB/cBy and CXBK, and some are unresponsive, such as C57BL/6 and CXBH.

Animals↗

Brain protein synthesis rates are not sensitive to elevated GABA, taurine, or glycine.

The effects of elevated levels of GABA, glycine, or taurine on the rate of protein synthesis in plasma, brain, liver, and muscle of adult mice were measured in in vivo experiments after a flooding dose of labeled valine. Elevation of these amino acids caused hypothermia; keeping the animals in an incubator maintained physiological body temperature. The increase in GABA or glycine did not affect the rate of protein synthesis in these tissues to a significant degree. The increase in taurine levels caused inhibition of valine incorporation in plasma, liver, and muscle, while brain protein synthesis was unaffected. When glycine was increased in brain, the uptake of labeled free valine in the brain was greater.

Animals↗

Glycine potentiates the action of some anticonvulsant drugs in some seizure models.

The anticonvulsant effect of either phenobarbital or dilantin was potentiated by exogenous glycine in DBA/2 audiogenic seizure mice and in 3-mercaptopropionic acid-induced seizures. In seizures caused by pentylenetetrazol, glycine potentiated the anticonvulsant effect of phenobarbital only slightly; in combination with dilantin, which was ineffective by itself, it did not have an effect. Valproic acid, in large doses, prevented 3-mercaptopropionic acid-induced seizures; glycine did not potentiate its effect. Glycine thus potentiates anticonvulsant effects, but only of some drugs and only in some of the seizure models. This suggests that the mechanism of the anticonvulsant effect of glycine is similar to that of some of the anticonvulsant drugs such as dilantin and different from others, and that this mechanism is not effective in all seizure models.

3-Mercaptopropionic Acid↗

Effect of chronic ethanol administration on brain protein breakdown in mice in vivo.

Brain proteins of BALB/cBy mice were labeled for a period of 8 days by a single intraperitoneal injection of valine. Following this the mice received 10% ethanol and protein breakdown was estimated from the release of label from brain proteins. Ethanol intake resulted in a significant inhibition of cerebral protein breakdown in vivo as measured in whole brain and in subcellular brain fractions (myelin, synaptosomes, mitochondria, microsomes, and nuclei). The intake of 10% ethanol for 4.5 months resulted in minor alterations in amino acid levels; increase in some and decrease in others were observed in plasma and brain, but most of the changes were not significant (P greater than 0.05). The uptake of AIB in brain was decreased 17% by prolonged ethanol intake.

Alcoholism↗

Platelet release of beta-thromboglobulin within the coronary circulation during cold pressor stress.

Cold stress by increasing circulating catecholamines may sensitize blood platelets to aggregate and release their constituents. This study investigates the effect of cold stress on the release of the platelet-specific protein beta-thromboglobulin into the coronary venous blood of 12 subjects with atherosclerotic coronary artery disease (CAD) and 7 subjects with angiographically normal coronary arteries (NCA). Cold pressor stress caused a greater increase in systolic arterial pressure in patients with CAD than in subjects with NCA (p less than 0.05). There was no significant difference between the platelet counts in the arterial or coronary venous blood either before or during cold stress. Arterial beta-thromboglobulin was higher in the group with CAD (77 +/- 18 ng/ml) than in subjects with NCA (49 +/- 12 ng/ml, p less than 0.01). Although there was no arteriovenous difference of beta-thromboglobulin at rest in either group, during cold stress, coronary venous beta-thromboglobulin increased in both the NCA (53 +/- 16 to 95 +/- 26 ng/ml, p less than 0.05) and CAD groups (76 +/- 13 to 117 +/- 53 ng/ml, p less than 0.025) despite no change in arterial beta-thromboglobulin. Release of beta-thromboglobulin, although not related to the presence of angiographic arterial disease, correlated with the systolic arterial pressure during cold stress (r = 0.66) and inversely with the platelet's ability to generate cyclic adenosine monophosphate (r = 0.69). The release of platelet constituents in the coronary circulation is provoked by cold stress and may play a role in stress-induced acute coronary occlusion in patients with atherosclerotic disease and in those with apparently normal vessels.

Beta-Globulins↗

Anticonvulsant effects of some inhibitory neurotransmitter amino acids.

The anticonvulsive effects of GABA, taurine, and glycine were investigated on several chemically-induced and genetic seizure models. Intravenous injections of either GABA, taurine, or glycine provided protection against 3-mercaptopropionic acid (MPA)-induced convulsions in adult Swiss mice. GABA was partially effective against isonicotinic acid hydrazide and was without effect against bicuculline-induced convulsions. Prolonged administration of glycine prevented MPA-induced convulsions but not electrically induced seizures or seizures induced by strychnine or metrazol. Intragastric glycine protected young audiogenic seizure-susceptible DBA/2 mice against all three phases of sound-induced convulsions (wild running, clonic and tonic seizure), but GABA and taurine provided little or no protection. With increase of glycine, the cerebral levels of glutamine and serine also increased, but that of glutamic acid decreased. The endogenous glutamic and glycine levels were slightly higher in the brains of the audiogenic seizure-susceptible DBA/2 mice than in that of the resistant BALB/Cy strain.

Acoustic Stimulation↗

Elevation of cerebral levels of nonessential amino acids in vivo by administration of large doses.

Taurine, aspartic acid, glutamic acid, glycine, and GABA were administered either intragastrically or in liquid diets to mice and rats. This resulted in a great increase in the plasma concentration of the administered amino acid, with plasma levels remaining elevated for several days. The prolonged increase in plasma levels resulted in significant increases in brain levels. Under these experimental conditions, taurine, aspartic acid, and glutamic acid were increased 30-60%; glycine and GABA 100%. During these experiments, plasma levels of taurine, aspartate, and glutamate were below brain levels; those of glycine and GABA were above. The findings show that even slowly penetrating amino acid levels can be increased in brain after parenteral administration of large doses.

Amino Acids↗

[Comparative analysis of the situation of intensive care (author's transl)].

Intensive care in Hungary in most of the medium size and major hospitals is provided on a proper level thanks for a great effort. The areal distribution of intensive care units is satisfactory. In case that a special intervention cannot be realized in one of the departments lack of instruments or expert personal, usually there is a possibility within 50--70 km distance in another unit to carry out this intervention. As a result of controlled development at the end of the sixth five year plan the units will come up quantitatively as well as qualitatively with all the needs for intensive care. In the present--let us hope transitory--situation the lack of expert personal, out of date hospital constructions and the great variety in types of instruments are meaning serious problems. The difficulties are exaggerrated by the fact that the work on an intensive care unit puts on an increased physical and psychological burden. As a result, in spite of all their interest and beauty the intensive care and its counter pair the anaesthesiology are among the less inviting professions with high incidence of migration and fluctuation of the personal.

Critical Care↗

A platelet procoagulant activity associated with platelet shape change.

PCA was measured for human PRP by determining recalcification times assayed in a minimal-dilution, controlled PH/PCO2 system in a siliconized cuvette, with the use of light transmission measurements (aggregometry). Platelet shape, aggregation, and plasma clotting end points were assayed photometrically, with platelet morphology and aggregation studied in parallel by light microscopy. With varying concentrations of ADP preincubated with PRP initially containing essentially disc-shaped platelets, it was found that induced shape change in the absence of an aggregation is necessary and sufficient for the development of PCA. This was consistently measurable as a shortening of recalcification times by approximately 50% for suspensions of shape-changed platelets vs. disc-shaped platelets. The pharmacologic inhibition of the endoperoxide pathway-mediated platelet secondary aggregation and release by aspirin administered in vivo does not impair the ability of human platelets to develop this PCA. Inhibition of shape change with amounts of 5'-adenosine monophosphate insufficient to affect coagulation tests in the absence of platelets leads to 80% to 90% inhibition of the ADP-induced PCA. This PCA is shown to be fully reversible, with morphologic reversion of shape-changed platelets to the discoid form, and is shown to be distinct from other PCAs previously described for platelets activated in different ways, such as PF3 activity. It is suggested that the binding of coagulation factors to the platelet membrane may be regulated concomitantly with shape change.

Adenosine Diphosphate↗

Characterization of purely ecotropic and amphotropic naturally occurring wild mouse leukemia viruses.

Two new strains of murine leukemia virus, one (strain 4996) purely ecotropic and the other (strain 1313) purely amphotropic, were isolated from spontaneous lymphomas in aged wild mice (Mus musculus). The 4996 virus is the first wild mouse field isolate which consists solely of ecotropic virus without the concomitant presence of amphotropic virus. The 1313 isolate is distinct in host range from seven other previously described wild mouse amphotropic isolates and is also the only murine leukemia virus shown to replicate in chicken cells.

AKR murine leukemia virus↗

Effect of exogenous catecholamines in the amygdala of a 'rage' cat.

Minute amounts of epinephrine or norepinephrine alter the behavior of 'rage' cats (prepared by ventromedial hypothalamotomy) when these substances are focally instilled into both amygdalae via chronic brain cannulae capped with a silastic membrane. Hyperactive defense reactions are replaced by lethargy and placidity. Similar injections of epinephrine or norepinephrine into the amygdalae of normally placid cats who had not been subjected to ventromedial hypothalamotomy did not appreciably alter their behavior.

Amygdala↗