Biomedical subjects
Publications and source records attributed to L I Privalova.
Based on studies of environmental objects and of children's health, the authors justified systematic approach to hygienic evaluation of aluminium plant reconstruction stages, for rational management in minimizing risk of environmental pollution and for health preservation.
The authors summarize theoretical principles of increasing human resistence to toxic effects of inorganic compounds polluting occupational environment and habitat, exemplify practical use of this prophylactic trend.
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The paper provides evidence that there is a relationship of daily death rates to variations in the concentrations of total dust and some gaseous ambient pollutants. The great advantage of a procedure to analyze temporary variables is that it makes it possible to retrospectively use the available materials of routine monitoring of air pollution and to consider these effects (cases of death in particular). Along with the high informative value of environmental and epidemiological surveys (EES) based on the analysis of time series, this advantage allows one to recommend them for widely use within the sociohygienic monitoring system. At the same time the paper shows it necessary to control the quality of available data and to chose monitoring centers comparable in this regard. Inevitable missing data on the concentrations of different pollutants on days off and on some working days are of particular value under the actual conditions of monitoring of air pollution. The approach applied in this study to the choice of the most effective ways of filling of such gaps may be recommended. Nevertheless, incomplete data and the need for their artificial reproduction should be regarded as a source of uncertainty of specific results of EES of this type. Increments in mortality rates for a certain increase in the concentrations of pollutants may be used in the risk assessment projects when a dose-response relationship is analyzed. The larger number of EES based on the analysis of time series will be conducted in the regions of Russia, the more reliable the use of EES-grounded single risks will be at the regional and federal level.
Dioxins and dioxin-like substances are highly toxic and extremely dangerous chemical compounds. Dioxins are formed during the thermal process associated with the use of chlorine. 2,3,7,8-tetrachlorodibenzo-1,4-dioxin is the most toxic, the most typical and well-studied agent. The most characteristic and constant indicators of intoxication with dioxin-containing substances are altered body weight, chloracne, hepatic damage, thyroid involution, structural changes in the adrenal cortex, spleen, genitals, immunodeficiency. There is evidence for a role of these agents in the development of infertility and neonatal pathology.
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The highly industrialized small town of Verkhnyaya Pyshma (in the Urals region of Russia) was chosen as the site of a multimedia-multipollutant risk assessment using the U.S. Environmental Protection Agency methodology. The assessment was based on routine environmental pollution monitoring data for ambient air, soils, drinking water, and food, and the international environmental epidemiology literature. Using an a priori set of the preliminary health-based criteria, we selected nine pollutants for risk assessment: total suspended particles (TSP), sulfur dioxide, nitrogen dioxide, benzo(a)pyrene (BaP), ammonia arsenic, copper, cadmium, and lead. We used dose-response functions derived from epidemiologic studies to assess individual and population risks for TSP, SO2, NO2, As, Cd, and Pb. We assessed both cancer (for BaP, As, and Cd) and non-cancer (for all the chosen pollutants but BaP) responses, but in this paper we discuss only the assessments of noncarcinogenic risks due to TSP, SO2, NO2, Pb, and Cd as examples of how the quantitative estimates of health effects can be produced by using a risk function approach. We also schematically present a modified conceptual model of multimedia-multipollutant risk assessment taking into account the experience gained with this study.
Elevation of average daily concentrations of suspended particles in air, even being within the MAC, could be associated with higher mortality in general population and deteriorated respiratory symptoms in children, especially in those having chronic respiratory diseases with bronchial obstruction. Discussion on reduction of MAC for suspended particles is expendient with wider practice of fraction measurement their concentrations.
The authors represent a scheme of conceptual model for methodology to evaluate health risk caused by environmental pollution. The model is based on analysis of literature and the authors' experience.
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The studies conducted in Krasnouralsk (Sverdlovsk region) proved that environmental pollution with lead in the area subjected to releases by copper-melting enterprise creates significant risk of lead accumulation in preschoolers especially prone to unfavorable factors. Considering various environmental lead sources, biokinetic analog formation reliably forecasts serum lead levels. Soil polluted with lead, as the analog considers, is the most important environmental lead source. The authors suggest a system of prophylactic measures based on analysis of children's health risk caused by environmental pollution with lead.
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Experiments on white rats proved that the silicotic pulmonary changes slowed with the tails periodically immersed into iodine solution. Those pulmonary changes were due to inhalation of quartzite dust and especially due to intratracheal administration of standardized quartz dust DQ12. Influenced by inhalation of dust containing quartz, the rats demonstrated characteristic alterations in cytologic features of bronchial and alveolar lavage water. The "iodine baths" also declined those alterations, that may prove higher resistance of pulmonary macrophages to cytotoxic effects of quartz. This hypothesis finds a support in experiments with culture of rat peritoneal macrophages. If incubated in a medium with low iodine concentrations and subsequently washed off, the macrophages demonstrate lower incidence of cytotoxic effects due to the next incubation with particles of DQ12. The macrophage's higher resistance against cytotoxic agents is believed to result directly in antisilicotic effect of iodine, so "iodine baths" could be recommended for pathogenetic therapy and medical prophylaxis of silicosis.
The authors proved that animals having higher natural antioxidant activity and lower intensity of lipid peroxidation are more resistant to fibrogenic effects of quartz. The peritoneal macrophages obtained from those animals show higher resistance to quartz exposure "in vitro". Parameters characterizing antioxidant system should be included into a group of indexes describing propensity to silicosis.
A multicompartmental mathematical model has been used to simulate variations in the cytotoxicity of dusts in the kinetics of the retention, in the pulmonary region and tracheobronchial lymph nodes, of practically insoluble quartzite and titanium dioxide dust particles deposited on the free surfaces of the acini from alveolar air. Experiments with these dusts were conducted on rats exposed to virtually the same dust concentrations in the air for an experimental period of 20 weeks and a period of 10 weeks after exposure. Satisfactory approximation to the experimental data on the retention of these dusts is obtained by using the model parameters that depend either on damage to lung macrophages by phagocytosed particles or on the response of the host organism to this damage by enhanced recruitment of neutrophilic leucocytes; all the other variables of the model being unchanged. The values of the "action integral" computed from this model and multiplied by the index of comparative cytotoxicity of particles in vitro satisfactorily approximate to quantitative differences in the intensity of pneumoconioses caused by the dusts under study by the end of the experimental period. On the whole, the results of the mathematical model agree with the hypothesis that the cytotoxicity of particles plays a key part in both the process of retention of dust in the lung parenchyma and lung associated lymph nodes, and the pathological process caused by the retained dust. Thus given the factors and conditions on which the deposition of practically insoluble dusts in the pulmonary region depends, it is necessary to take into account the multiplicative nature of these two effects of cytotoxicity when predicting the comparative risk of pneumoconiosis.
Detecting changes in humans that result from radioactive contamination of the area of residence many years after an incident (i.e., when the radiation has substantially decayed) presents a difficult epidemiological problem. Problems of this kind are even more complicated ina areas where the population is continually exposed to other harmful man-made factors. The city of Kamensk-Uralsky (Sverdlovsk region, Russia) is a good case in point. In 1957, part of Kamensk-Uralsky was contaminated as the result of an accident at the Kyshtym nuclear plant. In addition, the population of the contaminated area is being exposed to atmospheric emissions from several industrial enterprises. Two comparable groups of residents were formed: one in the contaminated are and another in a control area within the same city characterized by similar levels of chemical pollution but substantially lower radioactive contamination. The groups were composed of only those people who had been living in these areas continually since time of the accident and who were under 15 years of age at the time of the accident. The groups were matched by sex, age, and socio-occupational characteristics. For each subject, data were gathered on more than 50 parameters including hematological, immunological, and biochemical indices of the health status. All these data were obtained from blood tests taken in the fall of 1992. Data processing was carried out with the help of a computerized mathematical pattern recognition methodology, which ensured reliable discrimination between the generalized health status in the areas under study. We found that the health status of inhabitants of the area more contaminated with radioactive fallouts was adversely affected by radiation.
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