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Biomedical subjects

G Berencsi

Publications and source records attributed to G Berencsi.

At least 55 records · Page 3Linked to original sources
PubMed1985

The geopathological significance of drinking water on the Great Hungarian Plain.

The author has stated that the teeth of the population of a village on the Great Hungarian Plain were much better in the last century than now concerning the quality of teeth. The water supply of the village has changed by the turn of the century, as the population began to drink the water of deep wells instead of that of the superficial ones. The relation between the decay of teeth and the change in the quality of drinking water could be detected on the basis of the chemical analysis of the water. The water of the last century contained much more fluoride than the water used at present. It must be pointed out that the change in the quality of drinking water was much more favourable from the point of view of epidemiology.

Dental Caries↗
PubMed1984

Additional data on the mutagenic effect of dinitro-o-cresol-containing herbicides.

In in vivo experiments in mice it was studied, on the one hand, whether 1 year after treatment with dinitro-o-cresol (DNOC)-containing herbicide it was possible to detect any increase in chromosome aberrations in the bone marrow cells of the mouse, and on the other hand, to learn the frequency of chromosome aberrations in the subsequent generations when the treatment of the male animals with DNOC-containing herbicide was continued in each generation and when it was discontinued before mating. The chromosome aberrations of the bone marrow cells of the treated mice were demonstrated even 1 year after the treatment. After the treatment of the male animals was continued in each subsequent generation, the chromosome aberrations in the embryos increased, whereas when it was discontinued, it decreased in the subsequent generations.

Animals↗
PubMed1984

Effects of paraquat on peroxide metabolism enzymes and lipid peroxidation in the rat.

Investigation has been made of how the LD50 and LD100 of PQ influence the peroxide metabolism enzymes and lipid peroxidation in organ homogenates and blood samples of the rat. The peroxide metabolism enzyme activities were changed in a concentration dependent manner. In general, the effect of the lower doses of PQ on the superoxide dismutase, catalase activities and lipid peroxidation are increased. The glutathione peroxidase activity was decreased. Higher doses of PQ enhanced all of enzyme activities and lipid peroxidation studied.

Animals↗
PubMed1984

Characterization of adenovirus hexon epitopes by monoclonal antibodies.

Three-thousand hybridoma clones were produced using crystallized hexon of human adenovirus type 1 for immunization. ELISA revealed 69 homospecific antibody producing clones. The monoclonals were reactive with both crystallized and non-crystallized purified soluble hexon preparations, as well as with the hexons derived from purified virions. Hexon preparations of 10 different human adenovirus species (members of 4 different subgenera) were used for the characterization of 33 monoclonal antibodies. ELISA and passive haemagglutination (HA) tests revealed 6 and 15 distinct reactivity patterns (RP) i.e. intertype cross-reaction of a given antibody with the panel of test-antigens, respectively. Four of these RP-s were identical by both techniques. Significant quantitative differences existed between extinction values in ELISA and HA-titres. The results indicate the presence of identical epitopes as well as epitypic relationships among the hexons. The common epitopes and the epitypic relationship seem to be characterized by 16 different interspecies specificities under the experimental conditions, which are independent of subgenus boundaries and are demonstrable in different combinations on the hexons of adenovirus species belonging either to the same or to different subgenera.

Adenoviruses, Human↗
PubMed1983

DNA structure, and hemagglutination properties of bovine adenovirus type 2 strains which bypass species specificity.

Bovine adenovirus type 2 (Ad bos 2) strains were examined which had been isolated during natural outbreaks among calves, and lambs in Hungary [Belák, S., Pálfi, V.: Arch. ges. Virusforsch. 46,366-369 (1974)]. Differences were detected in hemagglutination properties, and in the restriction site maps of the DNA, which seem to be sufficient to group isolates of Ad bos 2 into two subtypes (subspecies). Some of the strains, recovered from cattle including prototype strain No. 19 are suggested to be separated as subtype A. These viruses hemagglutinate bovine red blood cells, and the physical map of the DNA is similar to, or identical with that of the prototype strain. Virus strains tentatively grouped into subtype B are pathogenic for both cattle, and sheep under natural conditions. Members of subtype B hemagglutinate only rat erythrocytes, and characteristic differences may be detected with BamHI, EcoRI, KpnI, and SalI restriction endonucleases in comparison to the physical maps of the DNA of prototype virus. The genome size of all isolates tested was measured to be of Mr 19.5 to 20.0 X 10(6), similar to Ad ovi 1, 4, and Ad bos 4, and 6. All isolates of subtype B characteristics were shown to encapsidate heterogeneous genome populations which could be distinguished from those of subtype A by the presence of specific restriction endonuclease cleavage fragments with molar ratios of less than 1.0.

Adenoviridae↗
PubMed1983

New considerations on the time-dependence of toxic changes caused by paraquat poisoning.

1. We have studied the effects of the LD50 and LD100 of paraquat on mouse blood triglycerides and on the time-dependence of the blood clotting, the bleeding time, the number of thrombocytes, and the body temperature. 2. The examined components vary rapidly in response to the toxic doses of paraquat. The changes depend on, among others, the amount of paraquat administered. 3. They are suitable for rapid diagnosis and for establishment of the severity of the poisoning.

Animals↗
PubMed1983

Changes induced by Gramoxon in tissue phospholipids and phospholipid fatty acids in mouse and guinea-pig.

Following administration of the LD50 or the LD100 of Gramoxon (PQ), the phospholipids (PL) of the lung, liver and kidney were separated and both the PLs and the fatty acids isolable from them were examined quantitatively. The different doses of PQ caused different changes of the saturated and unsaturated fatty acids in the various organs. The changes in the PL unsaturated fatty acids point to PQ-induced lipid peroxidation enhancement and membrane damage.

Animals↗
PubMed1983

Restriction site maps of the human adenovirus type 8 DNA.

Restriction site maps of human adenovirus 8 (Ad h 8) were constructed with BamHI, HindIII, PstI, SalI and KpnI endonucleases. The genome size was found to be 22.1 to 22.3 X 10(6) Mr. Comparison of the results with the data available on h Ad subgenera A, B, C showed that the SalI enzyme revealed subgenus-specific differences in the genomes. Similar patterns of the SalI fragments in both type 8 and 10 suggest that the differences were specific for the subgenus D of h Ad.

Adenoviridae↗
PubMed1983

Possible causes of the loss of specific pBR322-Ad h 1 DNA recombinants following transfection.

Characteristics of pBR322/Ad h 1 DNA recombinants were studied which had been cloned using HindIII restriction endonuclease in a single "shot-gun" experiment. Both oxytetracycline and ampicillin resistance of the clones were found to be heterogeneous. Ad h 1 DNA fragments HindIII-A, and -C could be cloned only in combination with other fragments. Among the possible reasons of the loss of recombinants upon transfection the impairment of pBR322-specific gene functions by the inserts is discussed in addition to the increased tetracycline resistance, and the tertiary structure of recombinant DNA.

Adenoviruses, Human↗
PubMed1983

Adenoviruses and human tumors: regulation of eukaryotic chromatin structure?

Adenoviruses possess four early gene clusters. E1A, and E1B sequences are directly involved in the initiation of transformation of both rodent, and human cells. Oncogenic potential of the in vitro immortalized rodent cells is also dependent on the expression of E1A, and E1B. Genes E2A, and E2B are coding for DNA-binding proteins. These regions may influence the frequency of in vitro transformation if complete virions were used for the immortalization of rodent cells. The existence of the E3 gene cluster, which has been shown to be non-essential to the productive replication in certain host cells, is unique for the adenovirus family. Foreign DNA fragments inserted into E3 or replacing it may modify the host range of adenovirus, and may initiate oncogenic transformation of rodent cells. May cellular oncogenes replace the non-essential region of the adenoviral genome? Are host-range modifications, the formation of defective genomes, and interactions of viral, and cellular DNA in vivo biological properties of adenoviruses? These questions are discussed in the light of recent findings concerning virus-coded functions which may modify chromatin structure, and may be associated with oncogenic potential of adenoviruses in the natural hosts.

Adenoviruses, Human↗
PubMed1983

Polypeptides and immunoreactivity of empty adenovirus type 1 particles.

Two distinct CsCl-stable empty particle populations were characterized in human adenovirus type 1 infected cells. Different sensitivity to proteases and polypeptide composition indicate that empty capsids A and B are degradation products of two different assembly intermediates. Both empty particle populations react with antihexon antibodies similarly to complete virions. Thus the arrangement of exposed type-specific epitopes is suggested to be unchanged during virus assembly. Experimental evidence is presented that both antifibre and antihexon antibodies trigger structural changes of complete virions, which are initiating the specific loss of core protein V from antibody-aggregated virions.

Adenoviruses, Human↗
PubMed1982

The effects of five weeks treatment with dinitro-o-cresol- or trifluralin-containing pesticides on the germ cells of male mice.

The effects of two pesticides, the insecticide-herbicide Krezonit E, which contains 50% dinitro-o-cresol, and the herbicide Olitref, which contains 26% trifluralin (2,6-dinitro-N,N-dipropyl-4-trifluoromethylaniline), on the gonads and germ cells of male mice were studied. The pesticides were given twice a week for 5 weeks in i.p. doses of 0.6 mg kg-1 for Krezonit E and 6.0 mg kg-1 for Olitref. These doses are 1% of the i.p. LD50. Cytogenic analysis of germ cells carried out from 3 weeks onwards after the last treatment day showed that Olitref significantly increased the frequency of germinal chromosomal abnormalities at 6-7 weeks after treatment. This pesticide increased the frequency of autosomal univalents X/Y separations at meiotic metaphase and multivalent configurations. Krezonit E did not increase significantly the number of chromosomal abnormalities, although there was some increase at 3 weeks, mainly in the form of autosomal univalents.

Animals↗
PubMed1982

Some new data to the toxicological effects of paraquat and the therapy.

1. Substances previously tested therapeutically were studied to obtain evidence on the pathomechanism in mice of paraquat, the active ingredient of Gramoxon, connected with the radicals formed from molecular oxygen, and also to extend the therapeutic possibilities. 2. The effects of these substances were assessed on the basis of the 72-hr survival rate and the percentage ratio of the wet lung weight to the overall body weight. 3. Other toxicological parameters too were followed. 4. Our present investigations indicate that, in agreement with our earlier results, besides reduced glutathione and ascorbic acid, vitamin E and C-ase are of the greatest importance from the aspect of the protection against paraquat toxicity. 5. In addition to those listed, other materials too, e.g. antifibrotic substances, naturally possess considerable detoxicating properties too.

Animals↗
PubMed1982

Study of the effects of paraquat on the peroxide metabolism enzymes in guinea-pig.

1. Guinea-pigs, which exhibit a similar metabolism to that of man insofar as they are incapable of synthesizing ascorbic acid, were poisoned with Gramoxon containing the LD50 or LD100 of paraquat. 2. A study was made of how the paraquat poisoning affected previously investigated tissue parameters, the superoxide dismutase, catalase and glutathione peroxidase activities and the lipid peroxidation. 3. In accordance with earlier results, the paraquat influences these parameters in different ways in all the tissues examined, depending on its concentration. 4. These parameters comprise primarily affected systems as regards paraquat toxicity.

Animals↗