[The toxicological characteristics of Gastrofenzin. IV. Its gonadotropic action].

An evaluation of the gonadotropic effect of Gastrofenzin has been carried out in conditions of 45-day and 90-day oral application (daily, 5 times per week) in male white rats. The experiments are performed in doses 1/20, 1/100 and 1/200 LD50, respectively 33.8, 6.

[The cytogenetic effects (the frequency of micronuclei) in lymphocyte cultures from the peripheral blood of workers in automobile tire manufacture].

At the Preparatory Workshop of the Plant for Automobile Tires (PAT), Sofia, complex investigations were undertaken to reveal possible genotoxic exposure. The studies included chemical analyses for levels of identifiable human carcinogens in the occupational ambient air (benz(a)pyrene, mineral oils, 2-naphthylamine); special techniques--questionnaire investigations and cytogenetic analysis by cytokinesis-block micronucleus method in peripheral lymphocyte cultures from 23 workers in occupational groups at risk; and urinalysis for contents of mercapturic acids. An out-of-house control group of 13 nonexposed subjects was concurrently investigated.

[The toxic hygiene problems of workers in the Dinamik automobile tire plant in Sofia].

Toxic hygienic investigations were carried out involving a representative group of 131 workers (50 females and 81 males) distributed into three main workshops--preparatory, confection, and vulcanization--at "Dynamic" automobile tire plant in Sofia. The majority of male and female workers were in the age range beyond 40 years, having a general occupational experience in excess of 10 years and specialized occupational experience from 10 to 20 years or more. The chemical hazard was among the leading ones in the occupational environment, differing in nature according to the technologies used.

[The action of the artichoke (Cynara scolymus) on the male gonads in an experiment].

The gonadotropic effect of the Bulgarian preparation artichoke, developed on the basis of Cynara scolymus is studied. The preparation is used under the form of 50% aque emulsion, stabilized by emulgent Twin-80, in doses 35.70 and 150 mg/kg-1, 5 times weekly for 75 days.

Toxicological evaluation of agromet (Metalaxyl) preparation.

A complex toxicological study was carried out in relation to the hygienic standardization of the fungicide preparation Ridomil, whose forthcoming production in this country will be under the name Metalaxyl. The study was performed on sexually mature white rats of both sexes, at oral, dermal and inhalation exposure, acute, subacute and chronic experiments, according to the Bulgarian State Standard. Besides the routine toxicological studies were carried also studies for establishing the long-term effects of the preparation (gonadotropic, embryotoxic and teratogenic, cardiovascular).

Dose effect relationship for some specific effects of dithiocarbamates.

The effect of zinc ethylenebisdithiocarbamate (zineb) and manganese ethylenebisdithiocarbamate (maneb) has been studied in a chronic experiment (4.5 months) on albino rat thyroid gland and gonads. A complex of biochemical, morphological (histological, histochemical and electronmicroscopic), radiological, functional and biological methods has been employed.

[Experimental research on the chronic inhalational toxicity of chloracetophon].

The chronic inhalational toxicity of chloracetophon was studied on 24 albino Wistar rats, with concentrations 20 mg X m-3. The animal were exposed 4 hours/daily, 5 days/weekly, for 90 days. Integral, biochemical, histological and electron-microscopic methods were used for the evaluation of the toxic effect of the preparation.

[Experimental assessment of the risk for offspring in lead exposure].

Multigenerational studies were carried out on albino rats obtained from parent progeny - female-intact and male-perorally exposed to lead acetate, in the drinking water - 0.2 mg/kg (group I) and 20 mg/kg (group II); the data were compared with a control group. Changes were found in each progeny as follows : in PI - reduced erythrocyte count, increased reticulocytes (group II); enhanced ATP activity in brain homogenates (group II), as will as increased disulphide groups in homogenates from brain, liver and testis (group II), highly reduced indices of fertility - 50% and of gestation - 62% (group II), in 100% level of the same indices in the control animals respectively.

[Current methodologic approaches to the study of various delayed effects of pesticides].

Studies on the possibilities of origination of remote sequelae (embryotoxic and teratogenic, gonadotropic, mutagenic, carcinogenic, alterations in cardiovascular system, etc) under the effect of the wide application of pesticides in the practice is one of the most important aspects of the present-day toxicology. Numerous of our studies in that field are directed to the pesticides, to fungicides in particular, the greater part of them being with mechanisms of biological activity, triggering changes in DNA synthesis and disturbances in cellular respiration. The results from our experimental studies are presented in the communication, with an aspect of alterations in the gonads, embryotoxicity and teratogenicity, of representatives of various groups of chemical preparations for plant protection.

[Assessment of the potential risk for progeny in work with endodan (experimental studies)].

An experimental assessment was made on endodan (ETM) effect, dithiocarbamate preparation, on the reproductive function of the parent generation albino rats, perorally intoxicated (by a sound) with doses 1/10 and 1/100 LD50, daily in the course of 6 months (LD50 = 380 mg/kg). The postnatal development of the three successive generations (F1, F2, F3) was studied. For that purpose, a complex of integral toxicological methods was used: weight, neurobehavioural activity, nortality (by 1st, 5th, 21st day), with the calculation of the indices of survival and lactation, and fertility with calculation of the indices of fertility and gestation and biochemical and clinical laboratory methods for the assessment of the functional state of liver, brain and testes.

[Assessment of the chronic toxic action of the herbicide, balagrin, in continuous and intermittent exposure regimens].

Chronic oral toxicity of the herbicide balagrin, a selective and perspective preparation for rural economy, was experimentally studied on 258 Wistar albino rats. Two treatment schedules using the combined trade product (20 percent balan and 80 percent xylol) were assayed: montonous - 1/20 LD50 balagrin (55 mg/kg) and 1/20 LD50 xylol (235 mg/kg), administered every day and every week for 4 months; intermittent - 4 months' every day application on alternate weeks of 1/10 LD50 balagrin (110 mg/kg) and 1/10 LD50 xylol (470 mg/kg) and 8 weeks' application by the same schedule of 1/20 LD50 balagrin and 1/20 LD50 xylol. The results of clinico-laboratory, biochemical and functional investigations showed that the toxic effect was more pronounced with monotonous administrations of the compound.

Study on the long-term effects of some pesticides.

The hygienic significance of the studies on pesticides from the aspect of their "long-term" effects upon the individual and the generations are emphasized. The basic methods and approaches used in the Laboratory of long-term effects with chemical etiology at the IHOH, Sofia, are discussed, namely for detecting the changes in gonads, reproduction and generation, embryotoxic and teratogenic effects, and changes in cardiovascular system. The results are discussed, namely: fundasol--the effect on gonads, generations, embryotoxic and teratogenic effects, changes in the cardiovascular system; endodan--changes in gonads, reproduction, embryotoxicity; basfungin--embryotoxic and teratogenic effects.

Changes in the gonads, reproduction and generations of white rats under the effect of some pesticides.

The problems of the gonadotropic effect of pesticides, together with changes in reproduction and in the offspring are of great interest and have drawn the attention of scientists during recent years. Assessment of these aspects should be made on the basis of integrated toxicological tests (weight, behaviour, mortality, fertility, etc.).

Experimental studies on the chronic toxic effects of vinyl chloride in rats.

Male rats were exposed to vinyl chloride at the concentrations of 50, 500, and 20 000 ppm, 5 hours daily, 5 days a week for 10 months. Morphological lesions in the liver and the testes detected by light and electron microscope and depression in body weight increase intensified with the duration of exposure. Increased relative weights of some organs and slight hematological and biochemical changes in blood during the course of the experiment were also observed.

[35S-cysteine incorporation into protein synthesis of the liver and testes in subacute oral poisoning with zineb, maneb and mancozeb].

35S-cysteine incorporation in the protein synthesis of liver and testes is studied in groups of 20 white rats each, following 14--day poisoning with dithiocarbamates, at doses 1/5 LD50, as follows: group one, cineb - o,180 g/kg, maneb - 0,140 g/kg, and mankozeb - 0,260 g/kg. Protein incorporation in liver and testes is studied after decapitation of the animals, within two hours of intraperitoneal 35S-cysteine injection at dose 15 micro C per rat. Liver and testes undergo appropriate treatment after the method of Munro et al.

[Changes in the gonads and reproductive capacity of white rats after oral maneb poisoning].

Changes in the gonads and reproduction capacity of white rats following oral intoxication with maneb are studied. The preparation at doses 1/10, 1/50, 1/100 and 1/5000 LD50 is administered to the starting generation of white rats twice weekly. Changes in the gonads--biochemical, histological, histoenzymatic and electron microscopic--are established, as well as a capacity for reproduction of the starting I and II offspring.

[Embryotoxic and teratogenic action of some pesticides].

The authors carried out experiments on white rats in order to evaluate embriotoxic and teratogenic effect of pesticides: cyneb, mneb, cypromate, basfungine, remrod, dipterex and bromex. The preparations were administered oraly as followed: 1) singly in the course of whole pregnancy in a dose of 1/2 LD50 and lower doses till finding single nonacting dose and 21 in the course of the whole pregnancy in doses rangling from the determined single threshold dose till finding minimal acting dose during multiple application and nonacting teratogenic dose under the same conditions. The authors examined the changes in some liver enzymic systems of the mother and fetus.