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Biomedical subjects

G Nagy

Publications and source records attributed to G Nagy.

At least 181 records · Page 10Linked to original sources
PubMed1984

The use of IgM tests for analysis of the causes of measles vaccine failures: experience gained in an epidemic in Hungary in 1980 and 1981.

Following a period of 6 years of low measles incidence, an epidemic occurred in Hungary with more than 11,000 reported cases between September 1980 and August 1981. About 60% of the cases had a documented history of previous measles vaccination. Serum samples obtained from 7815 patients were examined for measles antibody by haemagglutination inhibition (HI). In addition to conventional antibody titration, most of the sera or their IgM fraction obtained by a simple ion exchange chromatography were tested for the presence of measles-specific IgM antibodies by 2-mercaptoethanol (2-ME) treatment, and in 300 patients also by the fluorescent antibody (FA) technique. Laboratory results confirmed the diagnosis of measles in 5356 patients and supported it in 685 cases. Primary antibody response was found in 96.1% of unvaccinated and in 77.4% of previously vaccinated patients. The percentage of secondary antibody responses increased with increasing time from vaccination only in patients vaccinated before their first birthday, whereas in those who were immunized when over 12 months old, the distribution of primary and secondary antibody responses was independent from the time that had elapsed since vaccination. Therefore, secondary vaccine failure due to waning immunity account for only 6.2% of previously vaccinated patients, whereas in 93.8% of patients, including the majority of those with secondary antibody response, a primary failure of vaccination due to unsuccessful immunization was incriminated.

Adolescent↗
PubMed1984

(D-Met2,Pro5) enkephalinamide causes a decrease in plasma prolactin levels of lactating rats continuously suckled and an increase in those deprived of their litter.

The effect of an enkephalin analogue, (D-Met2,Pro5)enkephalinamide (EKNH2) on prolactin (PRL) secretion of lactating rats continuously suckled or separated from their pups was investigated. In rats together with their pups 0.5 mg/kg EKNH2 caused a dramatic decrease, 0.25 mg/kg a mild and short-lasting reduction in plasma PRL levels. In contrast, in lactating rats separated for 4 h from their pups 0.5 mg/kg of the drug induced a slight and 1.0 mg/kg a considerable increase in plasma PRL levels. The data indicate that in lactating rats depending on the circumstances the enkephalin analogue causes opposite effects on PRL secretion.

Animals↗
PubMed1984

Determination of enzyme activity in biological fluids by means of electrochemical oxidation of NADH at a modified glassy carbon electrode.

This amperometric technique for the determination of enzyme activity is based on detecting a decrease in the concentration of the NADH co-factor of the enzyme reaction. A glassy carbon electrode, modified by adsorption of Mg2+ and NADH, is used to measure the anodic peak current that corresponds to the oxidation of NADH. We found no significant difference between the enzyme activity of lactate dehydrogenase (E.C.1.1.1.27) preparations as measured by the above amperometric technique and by a spectrophotometric method.

Electrochemistry↗
PubMed1983

[Late skin symptoms of arsenic poisoning in the arsenic endemy in Bugac-Alsómonostor].

The population in an arsenic polluted area of Hungary was studied in respect of dermatological signs. Melanosis was observed in 23,75 per cent and keratosis in 10,83 per cent. Vitiligo has been present in 3 per cent of the population being partly associated to melanosis and partly independent. The observations suggest that arsenic does not only induce malignant neoplasms but also enhances development of benign skin tumours.

Adolescent↗
PubMed1983

Time course of the litter removal-induced depletion in plasma prolactin levels of lactating rats. An immediate full blockade of the hormone release after separation.

The decreases in plasma prolactin (PRL) levels in lactating rats that follow the separation of mother and pups have been studied. Blood samples were taken via an indwelling cannula from conscious primiparous animals between days 5 and 11 of lactation. Significant depressions of plasma prolactin levels have been detected within 3 min of separation. These decreases in hormone levels were most pronounced after 3 min, and continued up to the end of the 1st hour, but did not change during the 2nd hour. Disappearance of PRL from the blood during the first 3 min was identical to that occurring after hypophysectomy. Pretreatment of mothers, 90 min prior to separation, with alpha-methyl-p-tyrosine (250 mg/kg i.p.), pimozide (2 mg/kg i.p.), or haloperidol (2 mg/kg i.p.), completely blocked the decreases in PRL levels. L-Dopa (20 mg/rat i.p.) counteracted the inhibitory effect of alpha-methyl-p-tyrosine. These data suggest that separation of lactating rats from their litter resulted in a marked and complete blockade of PRL release from the pituitary. They also suggest that a dopaminergic mechanism plays an important role in this inhibition of PRL release.

Animals↗
PubMed1983

Circadian rhythms in plasma prolactin, luteinizing hormone and hypophyseal prolactin levels in lactating rats.

During a 24 h period lactating rats were decapitated at 2 h intervals and the trunk blood and pituitaries were collected. Suckling activity was registered at the time of sacrifice. Plasma prolactin (PRL), LH and hypophyseal (HYP) PRL levels were measured by RIA. The trough of the plasma PRL curve was at 09.30 h and was followed by about 4.5-fold elevation by 13.30 (the lights were on from 03.30 to 17.30). The plasma PRL levels showed 2.5-fold decrease by 19.30 h. The HYP PRL concentration exhibited 3.5-fold elevation from 01.30 to 05.30 h. After this peak concentration, the HYP PRL showed a 4-fold decrease at 11.30 h. A statistically non-significant rhythm was found in the plasma LH levels. Our data suggest that there are circadian rhythms in the plasma and HYP PRL levels of lactating rats in the early lactation period. The two rhythms are in an 8 h phase shift. Neither these rhythms nor the LH levels depended on the actual suckling activity of freely behaving lactating rats.

Animals↗
PubMed1983

Rapid decrease of plasma prolactin levels in lactating rats separated from their pups.

The time course of the effect of separation of the pups on plasma prolactin (PRL) of the mother and the mechanism of this effect were investigated in conscious primiparous lactating rats. Within the first 15 min the separation of the mother from her litter caused a very rapid decrease in the concentration of plasma PRL. There was already a very marked depression by the end of the first 3 min period. During the first 3 min the disappearance rate of PRL from the blood was identical to that occurring after hypophysectomy and thus similar to the biological half-life of plasma PRL in lactating rats. The observed marked decrease in PRL could be completely blocked by alpha-methyl-p-tyrosine pretreatment (250 mg kg-1 i.p.) or by haloperidol (2 mg kg-1 i.p.) at 90 min prior to the start of separation. It was demonstrated that the marked depression in plasma PRL concentration develops within the first hour and particularly in the first few minutes. Thus, the separation of lactating rats apparently results in an immediate complete blockade of PRL release from the pituitary. Finally, the data suggest that a dopaminergic mechanism plays an important role in the inhibition of PRL release induced by separation of the mother.

Animals↗