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Biomedical subjects

K Tóth

Publications and source records attributed to K Tóth.

At least 145 records · Page 8Linked to original sources
PubMed1986

[Simultaneous occurrence of malignant lymphoma and carcinoma in the stomach].

The simultaneous occurrence of malignant lymphoma and carcinoma of the stomach is described. The lymphoma proved to be of a high degree of malignancy. The malignant lymphoma was considered to be a primary tumor, followed by the development of the carcinoma. The patient survived for eight months after operation.

Carcinoma↗
PubMed1985

Physiological indicators of fluoride exposure and utilization: an epidemiological study.

Individual samples of urine, fingernails, head-hair, saliva, plaque and enamel were collected from three groups of Hungarian children, aged 14 years, who were exposed to contrasting water fluoride levels (less than or equal to 0.11 ppm; 0.5-1.1 ppm; 1.6-3.1 ppm). The mean fluoride concentration of the samples increased consistently and significantly, but mostly non-proportionately, with increasing water fluoride level. With the exception of plaque, the materials examined are considered suitable indicators of exposure to or systemic utilization of fluoride for population groups. Caries experience decreased with increasing fluoride exposure. Dental fluorosis constituted no clinical or aesthetic problem.

Adolescent↗
PubMed1985

[Not Available].

Explore the source record for details and available documents.

History, Modern 1601-↗
PubMed1984

UV-induced small structural changes in the T7 bacteriophage studied by melting methods.

UV optical absorption and circular dichroism (CD) properties (spectra and melting curves) of T7 bacteriophage were investigated to detect "in situ" structural damages which can be related to the biological inactivation due to UV irradiation. UV doses (0.2-1.2 kJ/m2 at 254 nm) near to the biologically effective minimal dose were applied where the initial genetic damage (approximately 10 events/phage) was observed. The decrease of the melting temperature of the helix-coil transition and the broadening of the transition range indicate the destabilization of the intraphage structure due to the presence of about 0.1-0.6% damaged base concentration.

Circular Dichroism↗
PubMed1984

Effect of herbicide 2,4,5-trichlorophenoxyethanol (TCPE) containing dioxin on mutation and induction of sister chromatid exchanges.

Previous studies have indicated that both herbicide 2,4,5-trichlorophenoxyethanol (TCPE) and its contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) enhance liver tumor incidence in male Swiss mice in a dose-dependent manner. In this report the mutagenicity of TCPE (containing 0.1 p.p.m. TCDD) in the Salmonella/microsome assay was studied, and the effect of this herbicide on the colony-forming ability and on the frequency of sister chromatid exchange (SCE) in Chinese hamster cells were determined. TCPE (1-500 micrograms/plate) appeared non-mutagenic in strains TA 1535, TA 1537, TA 1538, TA 98 and TA 100 either in the absence or presence of S-9 mix from male Wistar rat, male Swiss mouse and male hamster liver pre-treated by Aroclor 1254, using the standard plate incorporation and the pre-incubation assay. Male mouse urine, after a single administration of TCPE to the animal, also proved to be non-mutagenic in strains TA 98 and TA 100. In mammalian cell systems, however, TCPE directly induced a dose related increase in SCE frequency. The dose required to double the control SCE frequency was in the slightly toxic range of the survival curve for TCPE. The cytotoxicity was diminished both in bacterial and mammalian systems in the presence of S-9 mix from male Swiss mouse liver. This S-9 mix strongly reduced SCE frequency induced by TCPE. The induction of SCE observed cannot be attributed to the contaminant TCDD alone, because the SCE production was not influenced by the appropriate low concentration of pure TCDD.

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed1983

Effect of heat treatment on the glucocorticoid-receptor complex. Dependence on steroid structure.

The Arrhenius plot of heat inactivation of the rat liver glucocorticoid receptor protein gave a straight line with delta H++ = 115 kJ/mol over the 0-44 degrees C range. Molybdate ions were considerably protective but did not affect the linearity or slope of the Arrhenius plot. The effect of triamcinolone acetonide on heat stability of the receptor was similar to that of molybdate. On the other hand, glucocorticoid antagonists, although bound to the receptor, did not protect it from heat inactivation. Incubation of the complex of the glucocorticoid receptor with optimal glucocorticoids under activating conditions (elevated temperature or ionic strength) resulted in a considerable decrease in the dissociation rate. However, if the complex was incubated at 25 degrees C in the presence of molybdate, its dissociation rate did not change. Heat treatment without molybdate of complexes of glucocorticoid antagonists did not decrease the dissociation rate. These findings indicate that the decrease in dissociation rate is probably related to nucleophilic transformation. An 11 beta-hydroxyl group in the steroid structure seems to be an absolute requirement both for protection of the receptor against heat inactivation and for stabilization of the complex under conditions that promote nucleophilic transformation.

Animals↗
PubMed1983

Effects of some sugar alcohol derivatives on mutation and induction of sister chromatid exchanges.

The mutagenicity of various alkylating sugar alcohol derivatives in the Salmonella-microsome assay was studied, and the effects of these compounds on the colony-forming ability and the frequency of sister chromatid exchange (SCE) in Chinese hamster cells were determined. Cytostatic drugs under clinical trial [Elobromol (DBD), Myelobromol (DBM), Lycurim (LY), Zitostop (ZI)], others in preclinical analysis [dianhydrogalactitol (DAG), 3,4-diacetyldianhydrogalactitol (DiacDAG), 3,4-disuccinyldianhydrogalactitol (DisuDAG)], and compounds without any known antitumor effect in transplantable tumors [1-bromo-3,6-anhydrodulcitol (BAD), 1,2-epoxi-3,6-anhydrodulcitol (EAD)] were examined. All the tested compounds except DisuDAG were directly mutagenic in Salmonella strains TA 1535 and TA 100. The mutagenic effect of the chemicals was not influenced by S9 mix from rat liver, with the exception of ZI and DiacDAG. DisuDAG appeared nonmutagenic in strains TA 1535 and TA 100 exposed to microsomal enzymes from rat liver, lung, and kidney and mouse and hamster liver, nor was DisuDAG mutagenic in strains TA 1537, TA 1538, and TA 98 in either the presence or the absence of rat liver S9 mix. Mouse urine, after a single administration of DisuDAG to the animal, proved to be mutagenic in strain TA 1535. This effect can be attributed to the presence of DAG and EAD which could be identified by thin-layer chromatography of urine, thus establishing the premutagenic character of DisuDAG. All sugar alcohol derivatives increased the frequency of SCE. Doses required to double the control SCE frequency were in the sublethal range of the survival curve for DBD, DBM, LY, DAG, and DiacDAG. Doses higher than the sublethal ones were required of ZI, DisuDAG, BAD, and EAD to achieve a 2-fold increase in SCE frequency. On the basis of these doses, the relative potencies for SCE induction of the compounds were as follows: EAD less than BAD less than DisuDAG less than ZI less than DiacDAG less than DAG less than DBD less than DBM less than LY. Within this range, there was a 2 million-fold difference in the SCE production of these chemically related compounds.

Animals↗
PubMed1983

Disaccharidases in coeliac disease.

In 30 children presenting with complaints characteristic of malabsorption in whom congenital enzyme deficiency could be excluded, determination of the enzymes lactase, saccharase and maltase was performed in the tissue sample obtained by jejunal biopsy; histology was also carried out in all cases. In 23 cases the diagnosis of coeliac disease could subsequently be confirmed, in the other 7 cases the diagnosis could neither be rejected nor established with certainty. All three enzymes had a decreased activity in cases displaying subtotal or total villous atrophy, the most sensitive among them being lactase: in 69% of cases no lactase activity could be shown while saccharase and maltase were absent in 29 respectively 4% of the cases. No close correlation exists between the light-microscopic findings and the activity of enzymes since total absence of enzyme activity may be associated with only moderate villous atrophy. Lack of disaccharidase activity in the upper section of the small bowel does not necessarily mean disaccharide malabsorption exhibiting clinical symptoms, it only indicates a reduced capacity of disaccharide splitting. It has been concluded that routine determination of disaccharidase activities is not justified within the diagnostic procedure of coeliac disease.

Atrophy↗