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Biomedical subjects

L I Privalova

Publications and source records attributed to L I Privalova.

At least 37 records · Page 2Linked to original sources
PubMed1994

[Hygienic regulation of yttrium, terbium, ytterbium and lutetium fluorides in the air of the workplace].

The study (experiments on animals and on culture of rats' peritoneal macrophages) covered fluorides of rare-earth metals (REM) assigned to yttrium group--yttrium, terbium, ytterbium, lutetium. Fluorides of REM have low toxicity and cumulativity, induce no local irritation of skin and eyes. Fluorides of yttrium, terbium and lutetium, if administered into stomach, result in specific intoxication (fluorosis). Fluoride of ytterbium did not cause such intoxication. According to short-term tests of cytotoxicity, the foreseeable fibrogenic danger for ytterbium fluoride is moderate, for fluorides of yttrium, terbium and lutetium is mild. The authors recommend to control the level of yttrium, terbium and lutetium fluorides in the air of workplace through the MACs for the fluorides at 2.5 mg/cu m (maximal single concentration) and 0.5 mg/cu m (average shift concentration), the level of ytterbium fluoride as moderate fibrogenic dust at 6 mg/cu m.

Air Pollutants, Occupational↗
PubMed1994

[Experimental study on risk factors of pneumoconiosis caused by dust in the industry of new construction materials containing glass and coal waste].

The study compared cytotoxicity and fibrogenic ability of quartzitic dust to that appearing at 3 sites of light building filler production based on ground glass or clinker. Obtained results prove possible pneumoconiosis development caused by exposure to such dust types, especially in the production using ground glass. The MAC in this type of production is 2 mg/cu m, for the dust in production using clinker the MAC is 4 mg/cu m.

Air Pollutants, Occupational↗
PubMed1993

[Hygienic regulation of dust of magnesium-silicate minerals and fireproof materials].

Chronic experiments on rats showed that the dust of silicomagnesian refractory and dunite (a raw material for refractory production) extracted in Kytlym differ insignificantly in fibrogenic activity, but rank below the quartzite extracted in Pervouralsk (MAC-1 mg/cu m). The short study analyzing the cytologic changes of bronchoalveolar lavage determined the cytotoxicity of silicomagnesian refractory and 4 other types of dunite. The estimated cytotoxicity also ranked below that of quartzite from Pervouralsk. The MAC equal to 4 mg/cu m was suggested for the group of aerosols produced by dunite and silicomagnesian refractories. These aerosols are assigned to the 3rd jeopardy class and possess basically fibrogenic activity.

Animals↗
PubMed1993

[Significance of short-term cytotoxicity tests for hygienic assessment of industrial aerosols].

The evaluation of low-soluble particles toxicity for human phagocytes (primarily, for macrophages) was proved to have advantages in predicting their effects on the human body and in rapid toxico-hygienic regulation. The preference is given to tests "in vitro". If comparative toxicities of substances in group are discordant according to different "in vitro" tests the decision must be made after the "in vivo" evaluation of cytotoxicity: in 24 hours after the intratracheal administration of small doses of these low-soluble particles the bronchoalveolar lavage is examined cytologically. Reliable neutrophilia in lavage is of great value.

Administration, Inhalation↗
PubMed1992

Development of a multicompartmental model of the kinetics of quartz dust in the pulmonary region of the lung during chronic inhalation exposure of rats.

A multicompartmental model for the kinetics of dust retention in the pulmonary region of the lung and in the tracheobronchial lymph nodes has been developed. The model reflects the following ideas concerning the basic features of this process: (1) penetration into the pulmonary interstitium and translocation to the lymph nodes are possible for non-phagocytized particles only; (2) these processes depend on the degree of damage to macrophages by dust and on the extent of compensatory enhancement in the recruitment of neutrophils taking part in the clearance of the pulmonary region free surface; (3) a certain proportion of initially penetrating particles is continuously returned to this surface together with recruited pulmonary macrophages. The model ensures a satisfactory approximation to experimental data on the retention of quartz in the lung and lymph nodes during long term inhalation exposure, and simulation of the kinetic effects associated with both the damage to and the protection of the macrophagal clearance mechanism.

Animals↗
PubMed1991

[A multi-chamber model of quartz dust kinetics in the pulmonary region during chronic inhalation exposure in rats].

The contributors propose a multichamber model for the assessment of dust particles' concentration, elimination and translocation in deep pulmonary zones. The choice of the model structure is dominated by the following criteria: that dust penetration into the interstitial pulmonary tissues and its translocation to the lymph nodes can be performed by non-phagocytized particle only; that these processes depend on the degree of dust-induced lesions in the macrophages and the growth of compensating neutrophilic phagocytosis; that part of the penetrating particles would continuously return to the free surface of the pulmonary zone together with the mobilized interstitial lung macrophages. The model adequately corresponds to the experimental data obtained in prolonged inhalation experiments, and imitates the kinetic effects related to severe damages and protection of the pulmonary clearance macrophage mechanisms.

Administration, Inhalation↗
PubMed1989

Trends and perspectives of the biological prophylaxis of silicosis.

Based on earlier paper in this journal, as well as on new data concerning factors predetermining individual susceptibility to silicosis, we propose a comprehensive system of recommendations aimed at increasing the working population's resistance against the harmful action of silica dust. These recommendations consider, on one hand, the criteria of possible selection for employment in dusty industries of individuals who do not possess characteristics making them especially sensitive to this harmful action (collective biological prophylaxis), and on the other hand, the influences that could diminish such sensitivity (individual biological prophylaxis). Some ethical and practical problems of the biological prophylaxis of occupational diseases and a mathematical approach to predicting its effectiveness are also discussed.

Age Factors↗
PubMed1989

[Effects of immunization on quartz resistance and phagocytic activity of macrophages].

The experiments on Wistar rats revealed that after their immunization by ram erythrocytes rats' peritoneal and alveolar macrophage possessed significantly higher resistance to cytotoxic effects of standard quartz in vitro compared to macrophage of control animals. Initial immunization greatly increases the capacity of peritoneal macrophage to absorb suspended polystyrene latex particles. Both immunized and nonimmunized rats had similar mobilization of phagocyte-able cells into respiratory tracts in response to intratracheal destruction product administration. Theoretical and applied aspects of the obtained results were discussed.

Animals↗
PubMed1989

[Basic principles of protective reactions of phagocytic cells of the respiratory tract to deposition of cytotoxic dust particles and its regulation].

The relation of self-purification of the alveolar lung region from dust particles with mobilization and functional activity of macrophages and neutrophils is presented. A special impetus has been given to neutrophils' contribution growing along with the increase of dust cytotoxicity or decrease of macrophage resistance to its effect. Protective and compensatory mechanisms of phagocytic-response to dust deposit in the lungs are governed by an autoregulatory way as a function of the amount of macrophage destruction products. The ratio of neutrophils and macrophages in a cellular population of the bronchoalveolar lavage can serve as an information criterion of dust cytotoxicity (fibrogenicity, respectively). The level of the above mechanism response to macrophage destruction products depends on the neurohormonal background.

Animals↗
PubMed1989

[Effect of macrophage decay products on the incorporation of H3-thymidine into pulmonary cells in rats].

3H-thymidine is injected to Wistar rats 60 min before their sacrifice, that is performed 24 h after intratracheal administration of isotonic solution of natrium chloride (control), and in the test animals--24 or 72 h after similar injection of macrophage decay products (MDP). The MDP are prepared by freezing-thawing of syngenic peritoneal macrophages repeated 5 times in the dose corresponding to 10(8) of the destroyed cells per 100 g of body mass. During the first period after MDP injection the labelling index of macrophages, histiocytes and cells of the alveolar epithelium increases up to 4.07 +/- 0.21%, during the second--up to 3.34 +/- 0.17% (in the control--1.90 +/- 0.18%). The results obtained are discussed according to modern ideas on the role of the interstitial cell pool as an immediate source for mobilization of alveolar macrophages, and together with the data previously accumulated, on the role of MDP in the autoregulatory control of various links of the macrophagal pulmonary reaction.

Animals↗
PubMed1987

Some peculiarities of the pulmonary phagocytotic response: dust retention kinetics and silicosis development during long term exposure of rats to high quartz dust levels.

Rats were exposed to quartz dust (about 90 mg/m3) for five hours a day, five times a week either throughout the 48 weeks of the experiment or for a total of 40 weeks plus eight weeks of "rest." Cytological study of bronchoalveolar lavage showed that at a certain level of silicotic changes in the lungs, a pronounced breakdown in pulmonary dust clearance by macrophages could be observed. There was, however, a concomitant compensatory increase in the contribution to pulmonary phagocytosis by the neutrophil leukocytes (NL). As a result, pulmonary dust kinetics could be mathematically described using a constant clearance rate both throughout the 48 weeks of exposure and during the eight weeks after the end of the 40 week exposure. It is shown in a separate experiment that enhanced recruitment of NL into the airways may be due not only to an attractant effect of the products of macrophage breakdown (PMB) themselves but also to the release of an NL attractant factor by viable macrophages activated under influence of the PMB.

Animals↗
PubMed1986

Some aspects of the problem of individual predisposition to silicosis.

Based on experimental and epidemiological data findings presented here, as well as on data of other investigators, the authors conclude that a wide interindividual variability of susceptibility to silicosis is a real phenomenon. This susceptibility depends on both intrinsic features of the host and the influence of many environmental factors. The effect of any such factor is realized at different stages of silicosis pathogenesis and in close interrelation with the influence of other factors. The necessity of multifactorial analysis is stressed, and an example of such analysis is presented.

Acclimatization↗
PubMed1985

[Effect of carcinogenic substances on bone marrow cells in CBA mice].

The effect of some carcinogenic and non-carcinogenic agents on the content of CFUs and frequency of micronuclei (Howell-Jolly corps) in polychromatic erythrocytes of bone marrow cells was studied in CBA mice. Benzene administration decreased the content of CFUs in bone marrow cells, but this effect is considered to be rather a sign of its hematotropic than carcinogenic action. Changes in the CFUs amount induced by chrysotile-asbestos and quartz DQ-12 action were insignificant. All investigated carcinogenic agents (benz(a)pyrene, asbestos and benzene) significantly increased the number of micronuclei in polychromatic erythrocytes of bone marrow in mice.

Animals↗
PubMed1984

Recruitment of phagocytizing cells into the respiratory tract as a response to the cytotoxic action of deposited particles.

Recruitment of phagocytizing cells into the lower respiratory tract plays a very important role in the pulmonary dust clearance, depending both on the number of particles deposited therein and on their aggressiveness. The higher cytotoxicity of the particles, the greater the number of such cells recruited and the higher the contribution of the neutrophilic leukocytes (NL) into the free cellular population of airways which normally is represented chiefly by alveolar macrophages (AM). Adaptation of the alveolar dust phagocytosis to properties of inhaled particles operates through autoregulation of this process in which a key role is played by macrophage breakdown products (PMB). A series of experiments in vitro and in vivo showed that PMB stimulate AM and NL, enhance their recruitment into airways with a dose-dependent increase of the NL/AM ratio, promote recruitment of their precursors via blood and replenishment of such precursor reserves. The most active factor of the PMB appears to be lipidic by nature. The variability between individuals and between groups of alveolar phagocytosis response to particles of a given cytotoxicity may be due to differences of the host's neurohormonal status. It was shown that influencing the latter significantly shifts response to a standard dose of the PMB.

Animals↗
PubMed1982

On the defensive action of glutamate against the cytotoxicity and fibrogenicity of quartz dust.

The cytotoxic action of quartz (DQ12) particles on cultures of rat peritoneal macrophages, as estimated by the inhibition of the TTC-reductase activity, is considerably reduced by preincubation with glutamic acid and by adding sodium glutamate (15 mg/ml) to the drinking water of the rats donating the macrophages. This increase in macrophage resistance under the influence of glutamate is the most probable cause of the delay in the development of silicotic fibrosis shown in several experiments on rats intratracheally injected with quartz and then treated by prolonged administration of glutamate. This effect is probably connected with the influence of glutamate on the stability of the macrophage membranes, which can in its turn be explained by different mechanisms, including the influence on the synthesis and phosphorylation of adenosine nucleotides. Such an influence was shown in rats receiving glutamate by the change of the ATP/ADP ratio in macrophages, but not in erythrocytes. The resistance of rat erythrocytes to the haemolytic action of quartz is also not influenced by the action of glutamate neither in vitro nor in vivo. Such differences in the influences of glutamate on two types of cells, equally susceptible to quartz cytotoxicity but considerably differing in the character of energy metabolism, is an indirect proof of the role of the latter in the realisation of the anticytotoxic, and thereby antifibrogenic, effect of glutamate.

Animals↗