[Clinical features of hypothyroidism depending on intensity of excitatory processes in the central nervous system].

The author studied the cause of thyroid gland disease in dependence on peculiarities of the central nervous system. 85 patients with thyroid gland disease have been observed. Hypothyroid condition was mostly observed among patients with intermediate type of CNS. The highest level of TTG was observed among AIT patients with weak type of CNS. The patients with intermediate type of CNS had the lowest TTG values compared with those who had other types of CNS. The time period of Achille's reflex was lower in patient with weak type of CNS.

[Assessment of functional state of the thyroid with the help of a table of symptoms].

The table of symptoms was proposed to assess a functional state of a thyroid gland without instrumental and hormonal tests during the examination of patients by general practitioners gynecologists, dermatologists, neurologists and psychiatrists. 144 patients with different kinds of thyroid gland diseases, 72 healthy subjects and 172 patients with different non thyroid gland diseases contributed to verifying the correctness of the table.

[The assessment of the occupational risk to workers in electric steel production]. / Otsenka na professionalniia risk na rabotnitsite ot elektrostomanodobiva.

These studies, centering on occupational environmental factors, biologic monitoring, and toxicodynamic investigations, involved a total of 105 workers distributed into eight job groups, who were 45 years, of age on the average and had from 5 to 10 years of special occupational experience at "Electrosteel" Works. Evidence was obtained for presence of unfavorable microclimate conditions, elevated equivalent levels of noise, excess of general and local vibrations, exposure to manganese aerosols, carbon monoxide, and nitrogen oxides; some of the subjects and deviations in hepatic status and connective tissue. Job groups found to be at risk were those of steel founders, crane workers, and pourers.

[The toxic hygiene problems of workers in the Dinamik automobile tire plant in Sofia]. / Toksikokhigienni problemi pri raboteshtite v zavod za avtomobilni gumi "Dinamik"--Sofiia.

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. Included were various chemical substances and compounds: synthetic rubbers, fillers (soot, chalk, kaolin); softeners (mazut, paraffin, etc.); accelerants (mercaptothiazoles--captax and altax); dithiocarbamates (thiuram); vulcacides (diphenylguanidine); antiwear agents (antioxidants and antiozonators-isopropyl-phenyl-paraphenylene diamine, naphthyl-beta-naphthylamine); antiaccelerants (phthalic anhydride, ets.); organic solvents and others. The indicated chemical substances and compounds, though often found at concentrations below the mean-shift MACs, do produce health impacts by virtue of prolonged and combined exposures. Use was made of the questionnaire method. Also, hematologic, clinical laboratory, and toxic chemical testing was performed. Findings pointed to changes in hemopoiesis, deviations in hepatic functional state, while sulfate and glucuronide values confirmed the workers' high exposures.

[The cytogenetic effects (the frequency of micronuclei) in lymphocyte cultures from the peripheral blood of workers in automobile tire manufacture]. / Tsitogenetichni (chestota na mikronukleusi) v limfotsitni kulturi ot periferna kruv na rabotnitsite ot proizvodstvoto na avtomobilni gumi.

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. For contents of benz(a)pyrene and mineral oils exceeding 2.5 to 3.5 times the respective occupational environment MACs, evidence from cytogenetic analysis showed substantial, 4-fold, increase in indexes of genotoxic impairment (frequency of micronucleated-binucleated lymphocytes, number of micronuclei per 1000 binucleated lymphocytes) in the workers investigated. These results are an indicator of genotoxic exposure and point to an increased potential risk of cancer development in the group of workers studied.

[The basic parameters affecting the taking of air samples by concentration methods--the absorption method]. / Osnovni parametri, vliiaeshti vurkhu vzemaneto na probi ot vuzdukha po kontsentratsionni metodi--absorbtsionen metod.

The role of major factors influencing sampling effectiveness if using fluid absorbing media for studies of air pollution was investigated. The decisive role proved to be played by volatility of the substances used. Highly effective sampling was achieved with low volatility substances, or when chemical interaction between the absorbing medium and the substance to be studied resulted in compounds of low volatility.

[The basic parameters affecting the taking of air samples by concentration methods--the adsorption method]. / Osnovni parametri, vliiaeshti vurkhu vzemaneto na probi ot vuzdukha po kontsentratsionni metodi--adsorbtsionen metod.

To obtain reliable results from examination of air sampled onto adsorbents, it is necessary to define the latters' basic parameters: adsorption capacity under sampling conditions, and analytical recovery in separating substances from the sampling medium in view of the next step, analysis. Using a system specially developed for the purpose, the above parameters were tested with five types of activated carbon.

[Toxic substances from the use of coolant lubricants]. / Toksichni veshtestva pri izpolzvane na smazochno-okhlazhdashti sredstva.

The results from gas-mass analysis of the mixture of products from evaporation and volatile products from thermo-oxidizing destruction, eliminated at using lubricating-condensing devices point out, that the evaluation of the toxico-chemical factor concerning only the lubricated aerosol contact is extremely insufficient. The presence of hydrocarbons of different homologs, oxygen and nitrogen derivatives of hydrocarbons has to be taken into consideration. For correct characterization of the conditions of work and risk for the workers of these productions, creating conditions for destructive processes with lubricating oils, is necessary a standardization of the leading components of the vapour-gas phase in the air of the working environment.

[Harmful substances released during the thermal oxidative destruction of coolant lubricants]. / Vredni veshtestva, otdeliashti se pri termooksilitelna destruktsiia na smazochno-okhlazhdashti sredstva.

The use of lubricated oils in industry is related to processes of dispersing, evaporation and thermo-oxidizing destruction. As a result, in the air is eliminated a complex vaporous-gas aerosol mixture, consisting of lubricated aerosols, vapours and volatile products of evaporation and products of thermo-oxidizing destruction. In the vapour-gas phase are identified hydrocarbons [saturated, unsaturated, aromatic and cyclic] oxygen- containing hydrocarbon derivatives-aldehydes, ketones, esters, alcohols] in some cases CO. HCL. The composition of the mixture depends on the type of the lubricated oils and on the specific technological operation. The detailed study of the components of the mixture is a prerequisite for determining the leading toxic substances and for correct evaluation of the exposure and professional risk in industries, allowing a course of destructive processes with the lubricated oils.

[The level of mercapturic acids in the urine of workers in the petroleum refining industry]. / Nivo na merkapturovite kiselini v urinata na rabotnitsi ot neftoprerabotvashtata promishlenost.

Examination are carried out on 236 workers from three productions of oil-processing industry, who are exposed to the effect of hydrocarbons--saturated from the ethylene order, saturated (benzine), aromatic and sulphuric compounds--sulphur-containing organic, hydrogen sulphide, sulphur dioxide. The purpose of the study is to establish the risk of exposure to alkylating agents, which are potentially cancerogenic and mutagenic. Leading noxa in the production of high-octane aviation benzine (production "sulfur acidic alkylation", are the sulphur containing organic compounds, hydrogen sulphide, and in some working places--hydrocarbons (benzine and aromatic); in the production of "Ethylene" and "Polypropylene" leading noxae are the saturated hydrocarbons, and the sulphur-containing organic compounds as well as the unsaturated hydrocarbons (ethylene and propylene). The mercapturic acids in urine are determined after the method of Malonova and Bardoday (1983), and the creatinine by the Böringer test. Tobacco smoking and taking of drugs is also considered when data processing. A control group of 30 persons is also examined. In the workers from the 3 enterprises the average values of mercapturic acids in smokers and non-smokers are higher than that of the control group. The differences are statistically significant in the group of non-smokers. The highest per cent of workers with increased content of mercapturic acids (above 8 mumol/mmol creatinine) is established in the production of "Polypropylene".

[The relationship of exposure to chemically harmful compounds and disorders of the health status in workers in ethylene production]. / Zavisimost mezhdu ekspozitsiiata na khimichnite vredni suedineniia i narusheniiata v zdravoslovnoto sustoianie na rabotnitsite ot proizvodstvo "Etilen".

On the basis of job characteristics of workers from the production "ethylene", chronometric studies and measurement of concentration from chemical compounds are developed professional diagrams and risk diagrams, which give a possibility for more precise account of the exposure to chemical noxious compounds (by figures). According to the values of the estimated total index of exposure 156 workers are distributed in 5 groups. Besides, 48 workers with prolonged length of service in the production and 37 persons control group are examined. The toxicological, haematological and biochemical indices are studied and the neuro-vegetative status traced. Mainly in the groups with high chemical exposure (first and second risk groups) and with prolonged length of service are established high per cent of workers with deviation in the examined indices, which give grounds to assert for the presence of dose-response relationship.

[Epidemiological studies on the manufacture of cross-linked polyethylene]. / Epidemiologichni prouchvaniia pri proizvodstvoto na omrezhen polietilen.

In the production of cross-linked polyethylene in the air of the working environment above the norm concentrations of acetophenon, dicumyl peroxide and antioxidant are established, which create unfavourable working conditions. During clinical and laboratory examinations of 55 workers, engaged in the production of cross-linked polyethylene, are registered subjective complaints from the irritating effect of the chemical noxae on the mucous membranes and skin. Methaemoglobinaemia is found in 4 workers. There are deviations in the functional state of the liver (transaminase, APh, GGTP and triglycerides) in the group "maintaining staff". The same workers have also increased quantity of metabolite hippuric acid in the urine. On the grounds of the results, the group "maintaining staff" is determined as risk group. Recommendations are made for follow-up care and work in controlled parameters of the working environment.

[Hygienic evaluation of working conditions in furniture factories]. / Khigienna otsenka na usloviiata na trud v mebelni predpriiatiia.

The studies embrace basic productive shops from two furniture enterprises with leading noxious factors of the work environment: toxic chemical substances, noise and vibration (local and general). The concentrations of nine chemical substances from the composition of the used acid-hardening varnishes (polishes) and carbamide-formaldehyde glue are defined. The total concentrations of the formed multicomponent mixtures of organic solvents are calculated. Data show that in a greater part of the work places are measured noise levels, surpassing the hygienic norms, from the range of medium to high frequency. The measured local and total vibrations are in the limits of the hygienic norms, provided that the exposure is limited to 15 minute daily. On the basis of the established concentration of the toxic chemical substances in the air of the work environment an assessment is made on the work conditions. The assessment is confirmed by the analysis of the objective changes in the examined specific biochemical, clinic and laboratory indices of workers. Conclusion is given that the workers from these work places are subject to high occupational risk.

[New epidemiological study data on the manufacture of divinyl]. / Novi danni ot epidemiologichno prouchvane v proizvodstvoto na divinil.

Complex labour-hygienic studies were carried out on the working environment in divinyl production as well as on the health state of the workers. The leading deleterious factor of the environment are the concentrations of divinyl, hydrocarbons and ammonia above the norms. The latter have been determined by stationary and personal sample collecting. More than half of the workers examined work under labour conditions characterized as "particularly unfavourable" and "dangerous". In comparison with the hygienic characteristic by the middle of 1978-1980, a considerable increase of ammonia concentrations was established. A total of 102 workers have been covered by a complete clinical-laboratory examination. The results have been statistically processed with a view to establishing the correlation between the effect of the deleterious factors of the working environment and the deviations established in the health state of the workers. The following cases could be associated with occupational risk: cases with "positive" and "very likely" chronic ischemic heart disease as well as those with arterial hypertension, gastrointestinal diseases, chronic diseases of upper respiratory pathways with loss of sense of smell to various degrees, the neurological diseases--autonomic-vasal and neurotic syndrome, the cases of contact dermatitis and anemic syndrome.

[Assessment of the occupational risk to workers engaged in the manufacture of divinyl-styrene rubber]. / Otseniavane profesionalniia risk na rabotnitsi, zaeti v proizvodstvoto na divinil-stirolov kauchuk.

The production of synthetic rubber, one of the varieties of petro-chemical branch in our country, is new and very prospective. The Bulgarian synthetic rubber is synthesized from petroleum products divinyl and styrene. After the hygienic assessment of the technological processes, a complete characteristic of labour conditions was made and the character of the working process was studied of the main occupations of the workers, attending the installations of Synthetic Rubber Plant. The exposure to occupational noxae was determined and the existing occupational risk was evaluated. The toxico-chemical substances, benzene, styrene and divenyl, are with the highest significance among the factors of the working environment. The data on the health state of the workers are reported and recommendations are proposed for the restriction of the effect of the occupational factors.

[Basic work environment factors at the Kremikovtsi Coke Chemical Plant]. / Osnovni factori na rabotnata sreda v koksokhimichen zavod SMK "Kremikovtsi".

The investigations, carried out by the institute of Hygiene and Occupational Diseases, for the assessment of toxic-chemical and physical factors of the working environment in the metallurgical-chemical plant showed a high degree of air pollution with dust and high number of toxic substances, many of them manifestating an additive effect or effect of synergism. At certain working places the physical factors have manifested deleterious effect. On the base of the investigations carried out, recommendations are proposed for further investigations on proper assessment of the occupational risk and improvement of labour conditions.

[Problems of work hygiene in the manufacture of penicillin and streptomycin]. / Niakoi problemi na khigienata na truda pri proizvodstvoto na penitsilin i streptomitsin.

During the production of penicillin and streptomycin, substantially high concentrations of butyl alcohol and butylacetate are measured in the working environment atmosphere. The penicillin and streptomycin dust appears to be the chief unfavourable factor of the workplace in the drying, sorting and packing processes of the antibiotics. An unfavourable microclimate is observed only in the fermentation sections-- in the extraction and chemical purification, and particularly, in the drying process of the two antibiotics. The specific features of the working activities performed by vial examiners and sorters constitute factors predisposing to visual analysor strain. The latter might be also explained by changes taking place in the working ability and steadiness of attention in the course of the working shift.