PubMed Health⌕ Search

Biomedical subjects

T Popov

Publications and source records attributed to T Popov.

48 records · Page 3Linked to original sources
PubMed1982

[Prognosis and determination of the threshold of chronic effect of carbon disulfide and styrene].

Two series of studies were carried out: I--in workers exposed to four different mean annual CS2 concentrations--6 mg/m3; 12 mg/m3; 51 mg/m3 and 247 mg/m3 and II series-in workers exposed to three styrene concentrations--I mg/m3; 40 mg/m3 and 400 mg/m3. The results obtained in series I show the role of the primary toxic effect (inhibition of oxidases with mixed function) and of the adaptation reactions to it with a view to accurate specifying the threshold of chronic CS2 effect. The mathematical expression of the correlation between styrene concentration in air and blood, of phenyl-glyoxylic and mandelic acid in the urine of the exposed subjects enables the prognosis that the threshold of the noxious styrene effect is within the range of 150 mg/m3 to 250 mg/m3. A reduction on CS2 MAC is proposed--from 10 mg/m3 to I mg/m3 and the correction of styrene MAC--from 5 mg/m3 to 30-50 mg/m3.

Adult↗
PubMed1981

Experimental verification of the possibility of in vivo formation of nitrosocompounds upon combined action of dodecylguanidineacetate and sodium nitrite.

The pollution of the environment with pesticides of different chemical classes (amines, carbamates, guanidines, etc.) and nitrogen fertilizers creates the danger of the in vivo formation of carcinogenic nitrosocompounds. The fungicide Dodin represents dodecylguanidineacetate (DGA), whose chemical structure presupposes a possibility for nitrosofication in the presence of nitrites. The experiments were carried out on albino rats in which 1/10 LD50 sodium nitrite and DGA were introduced orally and in combination. On the 1st, 2nd, 4th, 8th, 15th and 30th days after the onset of the effect we determined the activity of the oxidases with mixed function (OMF) at two levels of biological organization: at the level of intact organism after loading with aminopyrine (AP) and subsequent determination of its basic metabolites in the urine; at subcellular level (microsomal liver fraction) - by the velocity of N-demethylation of AP, hydroxylation of aniline and by the cytochrome P-450 content. The independent action of sodium nitrite leads to a slight inhibition of OMF at subcellular level (28--34%) only after a single treatment. DGA does not change the activity of OMF. The combined action of the two agents causes considerable OMF inhibition (63--67 per cent) on the 1st, 2nd, 4th and 15th days at both levels. The concentration of microsomal protein decreases parallel to OMF inhibition. The data obtained suggest that a new compound is formed under the conditions of the experiment, probably through in vivo nitrosification of the pesticide. This is also testified by the established qualitatively different effect of the preliminary induction of OMF with phenobarbital on the acute toxicity of the noxae studied: lack of effect for DGA, increase for sodium nitrite and decrease for their combination.

Animals↗
PubMed1975

[The antigenic structure of vibrions studied by means of agglutination and fluorescent antibodies].

Cross immunofluorescent and serological studies were made of strains of Vibrio coli of different forms-a short, commashaped strain and other long, spiral-shaped and serpent-like strains isolated from swine. Some standard strains of Vibrio foetus were also included for comparison. An antigenic difference was established between vibrions of long and short forms, as well as the known difference between strains isolated from swine and those from cattle which can be established by means of immunofluorescent techniques. Combined studies using immunofluorescence and serological methods give the possibility for rapid group and species typing of different strains of vibrions.

Agglutination Tests↗
PubMedDate not supplied

[European multicenter cross-sectional study on exposure to low doses of benzene].

A cross-sectional multicenter european study has been carried out to evacuate the relations between exposure to low level of benzene and biological markers of internal dose (t,t-MA, S-PMA) and early biological effect (DNA-SSB). The research has shown significantly increased levels (adjusted for smoking habits) of the urinary excretion of t,t-MA, S-PMA and DNA-SSB in petrochemical workers (mean benzene level = 5,694 micrograms/m3) but not in filling station attendants, traffic police officers, and bus drivers compared to referent workers. Dose-response relations were detected between benzene air levels, t,t-MA, S-PMA and DNA-SSB in petrochemical workers, with significantly increased levels of DNA-SSB detected for benzene exposure levels in the range 391-1,800 micrograms/m3 (0.12-0.58 ppm).

Benzene↗