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C Oravec

Publications and source records attributed to C Oravec.

32 records · Page 2Linked to original sources
PubMed1979

The effect of interferon induction on complement level in rat.

Relatively high levels of interferon were achieved in rat sera by intracardial inoculation with Sindbis virus followed 15 min later by intraperitoneal application of dimethylsulfoxide. At intervals when interferon titres reached the maximum, the levels of complement were decreased as compared with the control group of rats. Single administration of dimethylsulfoxide did neither induce interferon nor influence the complement levels in sera of rats of the Dobrá Voda breed tested. Similar results were obtained with concentrated Newcastle disease virus inoculated intraperitoneally. Of interest is the finding that properdin levels seem to increase at the same time as interferon.

Animals↗
PubMed1978

Antilymphoid activity of leptospiral exoproducts.

Intraperitoneal application of supernatant fluid of L. patoc caused a pronounced and transient fall in peripheral lymphocyte count of Syrian hamsters. Pathogenic and possible cancerologic aspects of this findings are discussed.

Animals↗
PubMedDate not supplied

An evaluation of three pesticides: piritione, supercypermethrin and metolachlor in transformation bioassays of BHK21 and hamster embryo cells.

In a study of potential carcinogenicity of pesticides, Piritione, metolachlor (in the form of Dual and VUCHT 524) and Supercypermethrin (in the form of Supercypermethrin EC and Supercypermethrin TP) were assayed for induction of anchorage independent growth of BHK21 cells and morphological transformation of Syrian hamster embryo cells. The activity of these substances in both transformation assays was compared to the activity of the direct-acting ultimate carcinogen N-methyl-N-nitrosourea. In comparison to the very strong transforming activity of N-methyl-N-nitrosourea all pesticides tested with or without S9 fraction manifested a very weak, weak, medium or strong effect. The ability to induce anchorage independent growth was graded as follows: Dual < Supercypermethrin EC < Supercypermethrin TP < or = Piritione < VUCHT 524. Results of Syrian hamster embryo cell transformation assay were very similar to the BKH21 transformation assay. VUCHT 524 strongly induced transformation whereas Dual was inactive. Piritione and Supecypermethrin EC and Supercypermethrin TP elicited a slight but significant positive response.

Acetamides↗
PubMedDate not supplied

DNA damage, repair, replication, and tumor incidence in the BDIV rat strain following administration of N-ethyl-N-nitrosourea.

Berlin-Druckrey (BD-IV) rats were used to evaluate the level of neoplastic transformation, initiation of DNA damage and repair following treatment with N-ethyl-N-nitrosourea (ENU). ENU, a potent neurocarcinogen in the Sprague-Dawley (CD) and BDIX rat strains, was a less potent neurocarcinogen when administered to 30 day old BDIV rats. ENU induced significantly higher levels of tumors of the nervous system, kidney, and liver in CD rats than in BDIV rats. Initial DNA damage was determined by quantitating and comparing the number of alkaline labile sites (ALS) and alkylation of [14C]ENU to deoxyguanosine in the brain, kidney, and liver of BDIV rats. A smaller percentage of ALS were lost from the DNA of the brain (10-15%) than from the kidney (19-27%) and liver (30%). Similarly, loss of 0(6)-ethylguanine was greatest in liver (100%), next in kidney (73%), and least in brain (23%) DNA during a seven-day period. Loss of N7-ethylguanine ranged between 23-44%. These levels of repair are similar to those previously observed in the more sensitive Sprague-Dawley rat. Cellular replication was highest in the liver and lowest in the brain of BDIV rats at 30 days of age and was inhibited to varying extents in all three tissues by ENU. These data indicate, that while there is a good correlation between organ sensitivity to ENU induced carcinogenesis and the persistence of DNA lesions and levels of DNA replication in the same strain of rat, there is no correlation across strains with different carcinogenic potential.

Animals↗