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Biomedical subjects

L Varga

Publications and source records attributed to L Varga.

At least 109 records · Page 6Linked to original sources
PubMed1987

Prenatal fate of parthenogenetic cells in mouse aggregation chimaeras.

Parthenogenetically activated BCF1 and fertilized BALB/c embryos were aggregated to form chimaeras. The fate of the parthenogenetic component was followed in the conceptus during the second half of gestation. The results indicate an early strong selection against parthenogenetic cells in the extra-embryonal part, which is presumably complete by term, and a weaker selective process in the embryo. During early development, parthenogenetic cells have nearly normal developmental potency in the embryo, which allows their balanced contribution in the chimaeras on day 12. Later, this contribution declines significantly resulting in an unbalanced relation to the advantage of the fertilized counterpart. From the results, we suggest that gametic imprinting may play a role not only in the key steps of preimplantation and early postimplantation development, but later in cell and tissue differentiation.

Age Factors↗
PubMed1986

Structure and function of gastric corpus mucosa in suckling rats after treatment with 16,16-dimethyl prostaglandin E2.

Suckling rats were treated every 8 h by intragastric instillation of 16,16-dimethyl prostaglandin E2 (PG) from postnatal day 7 to 11. As compared to saline control treatment, PG increased the thickness of antral and corpus mucosa, the volume density of parietal cells, the mean individual parietal cell volume and pentagastrin-stimulated acid secretion at the end of the treatment. Plasma gastrin and corticosterone levels were depressed by PG while plasma thyroxine levels were unchanged. These structural and functional changes suggest PG-induced accelerated maturation of gastric mucosa.

16,16-Dimethylprostaglandin E2↗
PubMed1986

Immuno-, neuro-, and general toxicologic animal studies on a synthetic pyrethroid: cypermethrin.

The toxicologic properties of the synthetic pyrethroid insecticide cypermethrin have been studied in animal experiments. In the course of acute and subchronic experiments performed by the administration of 1/2 and 1/40, 1/20, and 1/10 proportions of the oral LD50 value, no considerable changes were found in the general toxicologic tests. The compound known to affect the central nervous system, however, induced only a mild enhancement of the central excitation level shown by the EEG investigations in the doses applied. In the immunotoxicologic studies an early and dose-dependent suppression was induced as a result of humoral immune response of rabbits immunised by S. typhi following the administration of cypermethrin. The cell-mediated immune response was also decreased. In rats the immune response determined by anti-sheep erythrocyte and antiovalbumin titer as well as by autologous rosette formation of spleen lymphocytes was hindered. The earliest detectable group of symptoms indicating the effect of a mild cypermethrin exposure is the appearance of the positivity of the immunotoxicologic tests. On the basis of the experimental findings the sensitive immunotoxicologic tests have been regarded as of great importance in the series of toxicologic methods.

Animals↗
PubMed1986

Rabbit plasma pretransferrin system: evidence for three new alleles.

Three additional pretransferrin types have been identified by one-dimensional PAGE technique in New Zealand White and Californian rabbits. The six alleles are designated PrtA, PrtB, PrtC, PrtD, PrtE and PrtF. It is likely that three of these six alleles are identical to those reported previously.

Alleles↗
PubMed1986

Effect of acid inhibition on the growth of parietal cells.

Studies in the rat have shown that prolonged inhibition of acid secretion by high doses of a histamine H2 antagonist is followed by a 20-30% increase in the number of parietal cells, and that this is paralleled by an augmentation of the maximum acid output. A similar effect has been shown after prolonged acid neutralization with high doses of an antacid. These trophic effects are not unexpected. An increase in gastric pH is followed by gastrin release, and the parietal cell mass may be augmented by repeated exogenous administration of gastrin or by endogenous hypergastrinaemia following surgery. To further evaluate whether a direct correlation exists between the magnitude of drug-induced hypergastrinaemia and parietal cell hyperplasia, rats were treated for 24 days with two acid inhibitors which differ markedly in the degree of acid inhibition and acute or chronic gastrin release. Six animals each were treated with either omeprazole (40 mumol/kg once daily), or atropine (3 mg/kg twice daily), or omeprazole combined with atropine or with placebo. On day 24, plasma gastrin was elevated more than 10-fold in both groups of rats treated with omeprazole but not in animals given atropine alone. As compared to placebo treatment, total parietal cell volume was significantly higher in animals treated with atropine (102 +/- 9 mm3 versus 140 +/- 18 mm3), but was unchanged in the other two groups. These studies demonstrate that marked prolonged drug-induced hypergastrinaemia does not necessarily exert trophic effects on parietal cells. Furthermore, the finding that omeprazole abolishes the effect of atropine suggests that omeprazole interferes with trophic actions on parietal cells.

Animals↗
PubMed1986

Repressed classical complement pathway activities and clinical correlations in chronic lymphocytic leukaemia.

Haemolytic activities of the classical and alternative complement pathways, and levels of C1, C4, C3, factor B and C1 inhibitor (C1-INH) were measured in 137 serum samples of 69 patients with chronic lymphocytic leukaemia (CLL). In most sera IgG, IgA and IgM concentrations were determined as well. Clinical correlations of these laboratory parameters have been studied. C1 and C4 activities were found to be depressed in almost 50% of the sera tested, and hypogammaglobulinaemia was observed with a similar frequency. Low C1 and C4 levels were found mainly in the early stages of the disease. A strong association between the occurrence of infections and hypogammaglobulinaemia was observed, although low immunoglobulin levels frequently occurred in patients without a history of infections. Low C1 and C4 levels were significantly correlated with the incidence of infections, too, and this correlation was observed mostly in the early stages of the disease. The reason for this is not known. The present results suggest that not only low immunoglobulin levels but low C1 and/or C4 levels may contribute to the increased susceptibility to infections in patients with chronic lymphocytic leukaemia.

Complement Activation↗
PubMed1986

Effects of secretin antibody on gastric acid inhibition and pancreatic bicarbonate stimulation by acidified liver extract meal in dogs.

Duodenal acidification is known to inhibit gastric H+ secretion while stimulating pancreatic HCO-3 secretion, but the mechanisms of these effects have not been fully explained. This study was designed to determine the role of endogenous and exogenous secretin in gastric inhibition and pancreatic stimulation by an acidified liver extract (LE) meal in conscious dogs prepared with chronic gastric and pancreatic fistulas pretreated with normal serum (control) or anti-secretin serum. In control tests, plasma gastrin and gastric H+ secretion showed a marked rise with LE meals at pH ranging from 7.0 to 4.0, but significantly declined at pH 3.0 and 2.0. Plasma secretin and pancreatic secretion started to rise with LE meals at pHs below 4.5, and both reached peaks at pH 2.0. Exogenous secretin infused at graded doses suppressed plasma gastrin and gastric H+ responses to LE meals at doses of 1.0 and 2.0 U/kg-h, but increased, dose-dependently, plasma secretin and pancreatic HCO-3 starting with a dose of 0.03 U/kg-h. Following the administration of anti-secretin serum, the effects of exogenous secretin on plasma gastrin and secretin levels as well as on gastric and pancreatic secretion were almost completely abolished. The increase in plasma secretin and pancreatic HCO-3 responses to LE meals at pH below 4.5 were also abolished by anti-secretin serum, but the suppression of plasma gastrin level and the inhibition of gastric H+ responses to LE meals at lower pH (3.0 and 2.0) remained virtually unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

[Psychosocial adaptation with an artificial intestinal outlet].

A total of 1625 patients with colostomy, ileostomy or urostomy, including all members of the Swiss ILCO Association, received a questionnaire concerning their medical, social, family and personal situation. 948 questionnaires were analyzed. The mean age was 64 and the time since operation 6 years. 60% regarded their postoperative instruction in stoma care as adequate, but 32% were unhappy with the preoperative information. The transstomal colonic irrigation technique was still unknown to 21% of the colostomy patients and was utilized by only 32%. One year after the operation 69% of the patients with colostomy, 83% with ileostomy and 59% with urostomy in the under-62 age group were fully reintegrated in their professions. Acceptance of the stoma by family and friends was good and there were no major difficulties in practising sports and other hobbies. Sexuality proved to be the most seriously affected aspect of their personal lives, as 33% male and 13% female patients reported major problems.

Adaptation, Psychological↗
PubMed1985

Immunotoxicological investigation of the effects of a pesticide; cypermethrin.

The effects of a synthetic pyrethroid pesticide cypermethrin on the immune system were studied. The effect of a daily oral administration of 1/40, 1/20 and 1/10 of LD50 was studied in rabbits for its influence on the humoral immune response after vaccination with Salmonella typhi, as well as on cell-mediated immunity. The two higher doses induced a significant dose-dependent decrease of serum antibody titers. The skin redness measured in the tuberculin skin test showed the same dose-dependent tendency. In subacute experiments with rats, a significant dose-dependent decrease was observed both in the anti-ovalbumin titer of blood sera measured in passive hemagglutination test and in the autologous rosette-formation of T-lymphocytes in groups fed the higher doses.

Animals↗
PubMed1985

Immunological alterations in anti-HTLV-III negative haemophiliacs and homosexual men in Hungary.

Hungary can be considered as a low risk area for AIDS since no patient with full-blown AIDS or AIDS-related complex has been found in the country. A complex clinical and immunological (T cell subsets, DNCB sensitization test, circulating immune complexes, acid-labile alpha interferon) investigation was performed between November, 1983 and June, 1984 in order to study whether alterations found in symptom-free homosexuals and haemophiliacs in the risk areas for AIDS can be observed in Hungary as well. 38 patients with mild haemophilia, 35 patients with severe haemophilia and 40 homosexual men were investigated in parallel to 37 heterosexual blood donors as controls. Anti-HTLV-III antibodies were measured later in the stored serum aliquots from the same subjects by the indirect membrane immunofluorescence assay. Although specific anti-HTLV-III antibodies were not detected in the haemophiliacs or homosexuals, immunological alterations characteristic for the members of AIDS risk groups in the high risk areas (decrease in the percentage of OKT4 cells and/or decrease of the OKT4/8 ratio) were found in one-third of the homosexuals and haemophiliacs tested. In addition, a significant part of these subjects did not develop delayed type hypersensitivity skin reaction on DNCB rechallenge. These findings indicate that an immunodeficiency independent of HTLV-III infection can be present in two major AIDS risk groups, in homosexual men and haemophiliacs.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Late hyponatremia in premature infants: role of aldosterone and arginine vasopressin.

To assess the possible involvement of arginine vasopressin in the pathogenesis of late hyponatremia in preterm infants, serial measurements of sodium balance, fractional sodium excretion, plasma and urine osmolality and sodium concentration, and urinary aldosterone and arginine vasopressin excretion were performed at weekly intervals in nine healthy preterm infants. During the course of late hyponatremia, there was a significant increase in urinary aldosterone and arginine vasopressin excretion, from 0.94 +/- 0.16 to 4.30 +/- 0.76 micrograms/day and from 0.38 +/- 0.08 to 1.19 +/- 0.26 ng/day, respectively, from the first to the fourth to fifth weeks. A significant negative correlation was found between fractional sodium excretion and urinary aldosterone excretion. Aldosterone excretion, however, correlated positively with urinary arginine vasopressin excretion in seven of the nine infants. The parallel increase in urinary aldosterone and arginine vasopressin excretion in salt-losing premature infants may occur in response to the protracted contraction of the extracellular fluid compartment, and may contribute to the restoration of volume in the body fluid compartments and to the development of late hyponatremia.

Aldosterone↗
PubMed1985

The effect of metoclopramide administration on electrolyte status and activity of renin-angiotensin-aldosterone system in premature infants.

The present study has been carried out to define whether endogenous dopamine contributes to the regulation of renal sodium handling and the function of the renin-angiotensin-aldosterone system in low birth weight premature infants. Twelve premature infants with mean birth weight of 1420 g and mean gestational age of 29.2 wk were given metoclopramide (MTC) in a dose of 0.1 mg/kg/day to treat delayed gastric emptying, regurgitation, and abdominal distension at the age of 17-23 days. Infants were kept on either a low (2-3 mEq/kg/day) or high (4-7 mEq/kg/day) sodium diet to modulate activity of RAAS. Prior to and after a 3-day period of MTC administration, blood samples were taken, and in six male infants 24-h urine collections were made to determine plasma and urine electrolytes, plasma renin activity, plasma aldosterone concentration, and urinary aldosterone excretion. We demonstrated that plasma sodium and potassium concentrations and plasma renin activity were not altered by MTC. On the other hand, in response to MTC, there was a significant increase in urinary sodium excretion (1.8 +/- 0.3 versus 2.3 +/- 0.3 mEq/kg/day) and a decrease in potassium excretion (1.2 +/- 0.2 versus 0.8 +/- 0.1 mEq/kg/day); plasma aldosterone concentration and urinary aldosterone excretion decreased significantly from initial values of 2101 +/- 274 pg/ml and 2.91 +/- 0.52 micrograms/day to 1500 +/- 207 pg/ml (p less than 0.01) and 2.21 +/- 0.43 micrograms/day (p less than 0.01), respectively, after MTC. These alterations were independent of the pretreatment hormone levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗
PubMed1985

Depressed classical complement pathway activities in chronic lymphocytic leukaemia.

Haemolytic activities of the classical and alternative complement pathways, and levels of C1, C4, C3, factor B and C1 inhibitor (C1-INH) were measured in 85 serum samples from 46 patients with chronic lymphocytic leukaemia (CLL). Significantly decreased mean C1 and C4 levels were found, and the haemolytic activities of these components were low or low normal in more than 50% of the sera tested. In 15 sera from 5 patients a complement profile characteristic of acquired C1-IHN deficiency was observed. These results indicate that the depression of the activity of the classical complement pathway is a frequently occurring feature in CLL.

Antigen-Antibody Complex↗