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Biomedical subjects

V Bencko

Publications and source records attributed to V Bencko.

At least 73 records · Page 4Linked to original sources
PubMed1988

Distribution and excretion of 74As and 75Se in rats after their simultaneous administration. The effect of arsenic, selenium and combined pretreatment.

The exposure of man to isolated toxic agent in the environment is rather a rare phenomenon. Therefore the study of a combined action of toxic substances is of increasing importance. The excretion and distribution of 74As (500 micrograms As.kg-1 b.wt.; Na74AsO2) and 75Se (525 micrograms Se.kg-1 b.wt.; Na275SeO3) was studied in rats after their separate and simultaneous i.v. injections. After simultaneous administration urinary as well as biliary excretion of 75Se and urinary excretion of 74As was increased in comparison with that in animals injected the radionuclides separately. Simultaneous administration of 74As and 75Se decreased concentration of 75Se in liver and increased concentration of 74As in kidney. In rats drinking water containing As (III) (0.66 mmol.l-1), Se(IV) (0.13 mmol.l-1) or combination As(III) + Se(IV) (at the same concentrations) for 7 or 28 days was studied the excretion and distribution of 74As and 75Se after their simultaneous i.v. injection (at the same concentrations and labelled compounds as mentioned above). The pretreatment with one element or with the combination of both elements significantly modified the distribution and excretion of subsequently administered 74As and 75Se.

Animals↗
PubMed1986

Human exposure to nickel and cobalt: biological monitoring and immunobiochemical response.

Thirty-eight production workers exposed to Ni and 35 exposed to Co were examined for the content of Ni and Co in hair, the serum concentration levels of immunoglobulins, IgG, IgA, IgM, and IgE, and serum proteins, alpha 2-macroglobulin (A2M), transferrin (TRF), alpha 1-antitrypsin (A1AT), ceruloplasmin (CPL), lysozyme (LYS), and alpha 1-glycoprotein (A1GP). Atomic absorption analysis of hair revealed that the respective geometric mean values of Ni and Co in Ni-exposed workers were 216.75 and 3.31 micrograms X g-1 and in Co-exposed workers 34.5 and 96.81 micrograms X g-1. These values were significantly higher than respective control values found in nonexposed individuals matched by age (Ni: 3.31 and Co: 0.38 micrograms X g-1). These findings suggest that hair analysis is a suitable method for the biological monitoring of exposure to these two metals. Tests for serum proteins revealed that nickel workers differed from controls by exhibiting significantly elevated IgG, IgA, and IgM levels; cobalt workers by a significant elevation of IgA level; and both exposed groups by a significant drop in the IgE level. A significant rise in the concentration (P less than 0.001-P less than 0.005) was also recorded in the case of A1AT, A2M, CPL, and LYS. The possible biomedical implications of these immunobiochemical findings are critically analyzed.

Adult↗
PubMed1986

Biological monitoring of environmental pollution and human exposure to some trace elements.

The extent of environmental pollution and resulting human exposure to hazardous toxic chemicals in the environment is often difficult to assess. One of the possible alternative approaches to this problem is the use of the biological indicators to demonstrate environmental pollution. This approach appears to be particularly suitable for demonstrating exposure to potentially toxic trace elements. In addition to analyses of plant and animal specimens the element content of human hair as an indicator of exposures to arsenic, mercury, cadmium, lead, antimony, manganese, nickel and cobalt has been repeatedly confirmed as reliable, provided the analyses were carried out and evaluated on group diagnostic basis and were done in groups of individuals occupationally not exposed to these metals. Preferably groups of 10-year-old children are to be used when only environmental pollution is to be taken into account. Hair samples are incomparably easier to collect, transport and store than the alternative biological material such as blood and urine used commonly to demonstrate exposure to various toxic agents. Biological monitoring of environmental pollution cannot replace the standard procedures of measuring air, water and soil pollution; however, the technique appears to have the potential of being an effective tool search for the extent of environmental pollution and for delimitation of territorial boundaries of areas affected most by hazardous emissions containing potentially toxic trace elements.

Activation Analysis↗
PubMed1986

Biomonitoring of environmental pollution hazards from a nickel smelter waste dump.

Longterm field exposure study was carried out on 10 rabbits placed for 6 months in a bioindication station located about 3 km downwind of a disposal site of nickel smelter waste dump. As revealed by the method of atomic absorption spectrophotometry, all of these animals showed elevated nickel and chromium levels in their body organs and hair. These findings were paralleled by histologic abnormalities in the lungs and liver tissues. Average dustfall values at the site of exposure did not exceed 5.5 g X m-2 X 30 d-1 during the period of observation. Dustfall deposits in this location contained nickel and chromium in amounts that were higher than in control locality. Analogous experiments on Wistar rats were carried out in a laboratory exposure chamber (exposure 4 h/day, 5 days/week, for a period of 6 months). After exposures to 50 mg X m-3 of metallic dust, lung parenchyma of rats was characterized by the presence of dust particles in various phases of phagocytosis as well as the presence of badly damaged or disintegrated alveolar macrophage cells, which pointed to metallic aerosol toxicity for biomembranes. The technique of air pollution biomonitoring on animals, correlated with the data on ambient air concentrations of the suspended particulate matter and its content of trace metals, appears to be a well suitable tool in establishing the potential air pollution hazards to the exposed populations living in the area of concern.

Air Pollutants, Occupational↗
PubMed1985

Incorporation of C14-thymidine and C14-uridine nucleosides into nucleic acid molecules in the liver of mice exposed to trivalent arsenic in drinking water.

The effect of trivalent arsenic on the C14-thymidine and C14-uridine incorporation into the liver nucleic acid molecules was studied in groups of mice exposed to 3.3 mmol . l-1 sodium arsenite in drinking water for 2, 4, 8, 16 and 32 days. In each exposure group, 18 h before the animals were killed by decapitation, six to ten mice were injected with 0.1 ml of C14-thymidine or C14-uridine of an activity of 0.37 MBq. The radioactivity of liver DNA and liver RNA fractions isolated and separated by extraction from the mouse liver homogenate was measured on a Betazcint BZ 5,000 scintillation counter and expressed as cpm . mg-1 of isolated nucleic acids. Initially, the rates at which the labeled thymidine and uridine nucleosides incorporated into the nucleic acid molecules showed a marked drop below the control value, then started to rise again, continuing to gradually increase as the time of arsenic exposure was increasing; they attained the control value on day 8, and at the last interval of observation (i.e. at 32 days of exposure to arsenic) they reached, respectively, 143% and 127% of the control value. The initial drop in the rate of nucleoside incorporation is believed to reflect the general metabolic inhibition caused by arsenic; the subsequent enhancement of the process of incorporation is ascribed to the induction of enzymes that are involved in the development of a tolerance for arsenic.

Animals↗
PubMed1985

Chromium: a review of environmental and occupational toxicology.

The following topics are covered in this brief review on the environmental and occupational toxicology of chromium: occurrence, production and uses of chromium and chromium compounds; experimental toxicology; chromium toxicity for man; hygienic and ecologic aspects of chromium contamination of the environment. The review provides a conclusive evidence which suggests that chromium, especially its hexavalent form, is both toxic and carcinogenic, but its trivalent form is physiologically essential in the metabolism of insulin. It is also emphasized that among the major sources of environmental chromium today are the cement industry and the increasingly widespread use of chromium compounds added as an anticorrosion admixture to a variety of cooling systems, e.g. in large power plants, which may greatly contribute to the overall pollution of outdoor air at the sites.

Aging↗
PubMed1984

To the problem of trace elements and hydrocarbons emissions from combustion of coal.

Coal is and at least by the end of this century is likely to remain the major source of energy in Czechoslovakia. Apart from the chronic air pollution problems associated with emissions of oxides of sulfur and flyash a growing attention is now increasingly centered on atmospheric trace elements emitted from coalfired power plants and on emission of hydrocarbons that are invariably detectable in the combustion product condensate. The air pollution emission data presented here are a result of systematic measurements of actual emissions. The measurement included virtually all larger power plants in Czechoslovakia and were carried out between 1975 and 1981. To allow for quantification of the emission data measured trace element mass balance was determined in these measurements. An attempt was also made to compare the relative power industry data obtained in Czechoslovakia with those reported from the USA. A broad spectrum of hydrocarbons found in the condensate of combustion products originating during the coal mass combustion seemed to indicate the presence of both burning and pyrolitic processes, but the mechanism of pyrolysis is as yet unclear. Apart from organics the condensate was found to contain a relatively large amount of fluoride compounds (hundreds of mg X 1(-1) condensate). There is suspicion that this fluorine may occupy an important position among the factors responsible for the ecologic damage caused by emissions from coal-fired power plants.

Air Pollutants↗
PubMed1984

Manganese: a review of occupational and environmental toxicology.

The following topics are dealt with in this brief review concerning the hygienic and toxicologic aspects of manganese: Occurrence, production, uses; experimental pathology; clinical toxicology; occupational and environmental hygiene aspects of human exposure. The preventive measures outlined: reduction of dust concentration to comply with the established MAC value, in extreme situation even with the use of personal protection; preventive pre-employment examinations to exclude from work all individuals with liver and kidney lesions, blood dyscrasia, organic CNS lesions and progressive lung diseases; elaboration of suitable exposure tests, especially the method of hair analysis, to ensure the biological monitoring of environmental exposure to manganese.

Animals↗
PubMed1983

Nickel: a review of its occupational and environmental toxicology.

Nickel and nickel compounds belong to the classic noxious agents encountered in industry, but is also known to affect non-occupationally exposed individuals, especially those handling stainless-steel and nickel plated articles of everyday use. For plants and some vertebrates, specifically for mammals, nickel is indispensable as one of the essential trace elements. The most important health problems due to exposure to nickel and nickel compounds are allergic dermatitis (nickel itch) and increased incidence of cancers of the lungs and nasal mucosa encountered among the workers after a long-term over-exposure to nickel. In this respect the most hazardous nickel compounds appear to be nickel sulfide and nickel oxide. The monitoring of nickel exposure levels can be based on blood serum and urine analyses, but also on nickel determinations in hair which have proved promising even in groups of non-occupationally exposed individuals. Nickel carbonyl is the most toxic of all of the nickel compounds encountered, but because of its relatively short half-life it does not seem to represent any actual biohazard from the standpoint of environmental pollution. To prevent incidence of malignancies it is recommended to include in the routine plan of the preventive medical examinations also the cytologic analysis supplemented, in the case of cytologic positivity, with the bioptic examination for epithelial dysplasia. A systematic medical surveillance of workers with known long-term exposure to nickel is, of course, essential. At present, a major attention is centered on biochemical interactions of nickel with copper, cadmium, iron, iodine and particularly with manganese known to significantly reduce the experimental carcinogenicity of nickel and nickel compounds.

Air↗
PubMed1983

Immuno-biochemical findings in groups of individuals occupationally and non-occupationally exposed to emissions containing nickel and cobalt.

Immune reactions elicited in the sera of individuals exposed to nickel and cobalt were assessed by changes in the concentration of serum immunoglobulins IgG, IgA and IgM and serum proteins alpha 2 macroglobulin (A2M), transferrin (TRF), alpha 1-antitrypsin (A1AT), ceruloplasmin (CPL) and lysozyme (LYS). Examinations were carried out in workers occupationally exposed to Ni (38 individuals) or Co (35 individuals) and in groups of non-occupationally exposed children living in areas with a different degree of air pollution from a nearby source of Ni and Co emissions (one group was made up of 54 exposed children, the other one of 64 "less exposed" children of the same age). Groups of non-exposed controls were represented by a group of 42 male adults matched by age and by a group of 48 children from a non-polluted area. Significantly increased average values were obtained for IgG, IgA and IgM in group of workers exposed to Ni, for IgA in workers exposed to Co and for A1AT, A2M, CPL and LYS in both groups of occupationally exposed adults (p less than 0.001 - p less than 0.005). Among non-occupationally exposed children the group of the most exposed had significantly elevated average values for A2M and A1AT which were higher than those recorded in groups of "less exposed" and control children (p less than 0.02 and p less than 0.05, respectively). The biomedical importance of these findings is discussed in detail.

Adult↗
PubMed1983

Hygienic and toxicological aspects of occupational and environmental exposure to beryllium.

As the production of missile, nuclear devices and electronics grew and modern industrial technologies emerged the risk of the occupational exposure to beryllium has become increasingly common and widespread. The environmental burden of beryllium is also on the increase, not only as a result of emissions from plants producing and processing beryllium, or its alloys and compounds, but also from burning coal of higher beryllium content in some localities. This article discusses primarily the hygienic and toxicologic aspects of beryllium and its threat to human health. The following topics are included in this review: occurrence, production and uses of beryllium; its metabolism and experimental toxicology; clinical toxicology and pathogenesis of berylliosis; hygienic and epidemiologic aspects of berylliosis; berylliosis treatment and prevention. Berylliosis is here characterized as a disease combining clinical manifestations of pneumosclerosis, allergy to beryllium and, in its granulomatous form, autoimmune reactions. Importantly, the available technical means and measures can ensure that the both occupational and environmental exposure to beryllium can be kept below the established MAC values. If occasionally impossible, special preventive measures should be adopted. It is essential that all persons with allergy be prophylactically excluded from work at risk of exposure to beryllium.

Animals↗
PubMed1982

Hygienic-toxicological aspects of exposure to lead. A critical review.

This review on hygienic, toxicologic and ecologic aspects of environmental burden of lead deals with the following topics: occurrence, production and use of lead; metabolism of lead and experimental toxicology of lead; toxicity of lead to man; hygienic and ecologic aspects of lead pollution. Lead ore mining and processing, production of lead-acid batteries and combustion of gasoline containing tetraethyl-lead as an anti-knock ingredient constitute at present the most important sources of lead pollution. The last named source of lead pollution in urban atmosphere is most hazardous to human health. Attempts to reduce this health hazard include use of additive-free gasoline, or replacement of tetraethyl lead by other anti-knock agents, e. g. by tetraethylcopper. The experiments with the use of organic compounds of manganese have failed to succeed. The possibility of biological monitoring of occupational and nonoccupational exposures to lead is discussed in detail in this review.

Anemia↗
PubMed1981

Use of domesticated rabbit tissues for monitoring of environmental pollution by toxic metals (Mn, Pb, Cr, Cd, Ni).

Domesticated rabbits were exposed to natural environmental conditions in an area polluted by emissions from a ferromanganese alloys producing plant. The samples of blood, liver, kidneys, bones, spleen, heart, muscle tissue and hair of rabbits were analyzed, after low-pressure low-temperature, ashing in RF oxygen plasma, for the presence of Mn, Pb, Cr, Cd and Ni, using the Varian Techtron AA 6-D apparatus. Groups of 3 rabbits were killed at the following time intervals: immediately after birth, and then after the exposure of 1, 2, 6 and 12 months. The levels of toxic metals detected in the examined biological samples were compared with those detected in control rabbits from non-polluted area. Contents of the analyzed toxic metals were also determined in animal feed samples as well as in samples of air (24-hour samples), drinking water and soil. The results show that the described biological monitoring might be feasibly coupled with the prepared epidemiological studies conducted in areas contaminated with toxic microelements or other persistent substances that are known to accumulate in the mammalian organism.

Animals↗
PubMed1981

Combined action of chromium and nickel on mouse and hamster fibroblast cell lines.

Suspension cultures of mouse fibroblasts L-A 115 and Chinese hamster 237-2a fibroblast were used to study combined action of chromium and nickel ions. The growth curve analysis of L-A cell lines revealed a lethal effect of Cr(VI) concentrations 10(-3)-10(-5)M on cultured cells, concentrations 10(-6)-10(-8)M produced a significant growth inhibition. On the other hand, Cr(III) concentrations 10(-3)-10(-5)M had no effect on cellular growth, which confirms that Cr(VI) is more toxic than Cr(III), even for cultured cells. Ni(II) concentration 10(-3)M was considerably cytotoxic, concentrations 10(-4)-10(-6)M had practically no effect on the cell growth. The combined action of two non-toxic concentrations Ni(II) 10(-5)M X Cr(III) 10(-3)M showed a pronounced of action and produced a 50% growth inhibition in comparison with controls. Surprising and unexpected results were also obtained by the cytogenetic analysis of Chinese hamster 237-2a cells exposed to the combination Ni(II) 10(-6)M X Cr(III) 10(-4)M; the number of detected aberrant cells was significantly lower than the number expected after a simple summation of actions. The reduced mutagenic activity of these Cr(III) and Ni(II) concentrations at their combined action can be ascribed to the stimulation of cellular repair mechanisms.

Animals↗
PubMed1980

Ultrastructural changes in hepatocytes of mice exposed to arsenic in drinking water.

Arsenic belongs to the important occupational and environmental agents which can cause damages to the liver by chronic exposure. In a long-term experimental (64 days) in mice the changes in liver cells due to arsenic were studied on the ultrastructural level. The qualitative and quantitative evaluation of the results obtained demonstrate two types of response. The first one was an acute reaction (maximum 4 days) characterized by enlargement of the surfaces of some inner membraneous structures of the hepatocytes (invaginations of the nuclear membrane and undulations of the mitochondrial surface) as well as by loss of glycogen. These changes receded gradually during the course of the experiment. The second type was characterized by a strikingly delayed change (maximum 32 days) represented by the occurrence of dense lamellar structures in the peroxisomes. Both types of response persisted till the termination of the experiment (64 days). The first type of response is considered to be a consequence of the direct toxic action of arsenic, the second one is interpreted as an expression of induced tolerance to arsenic of the organism.

Animals↗