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Biomedical subjects

A Brockhaus

Publications and source records attributed to A Brockhaus.

At least 55 records · Page 3Linked to original sources
PubMed1981

Intake and health effects of thallium among a population living in the vicinity of a cement plant emitting thallium containing dust.

In order to assess the degree of thallium exposure in a population living around a thallium emitting cement plant in a small city in North-West Germany thallium levels in 24 h urine samples of 1,265 subjects and in hair samples of 1,163 subjects were determined. Urinary thallium levels in two groups of subjects living in an urban and a rural area of West Germany were determined for reference. As compared to these subjects the population living around the cement plant exhibited obvious signs of increased thallium intake. The mean urinary thallium concentration was 2.6 micrograms/l and ranged up to 76.5 micrograms/l. In contrast, the mean urinary thallium levels of the two reference groups were 0.2 and 0.4 micrograms/l, respectively. Hair thallium levels of the population living around the cement plant were also markedly increased (mean: 9.5 ng/g). The major route of the population's increased intake of thallium was found to be the consumption of vegetables and fruit grown in private gardens in the vicinity of the cement plant. As was shown by chemical analyses vegetables and fruit grown in these gardens were contaminated by thallium-containing atmospheric dust fall-out caused by emissions of the cement plant. The pulmonary route of uptake as well as other sources did not seem to play a significant role in the population's exposure to thallium. Polyneuritic symptoms, sleep disorders, headache, fatigue and other signs of psychasthenia were found to be the major health effects associated with increased thallium levels in urine and hair. No positive correlation was found between the thallium levels in hair and urine and the prevalence of skin alterations, hair-loss and gastro-intestinal dysfunctions.

Adolescent↗
PubMed1980

[Studies on the tumourigenicity of extracts and their fractions of airborne particulates with the subcutaneous test in the mouse (author's transl)].

Airborne particulate matter was collected on filters at various times in Duisburg, Duesseldorf, Muenster and in 2 rural areas. After extraction with organic solvents the extract was partly fractionated and analyzed for BaP and 7 other polycyclic aromatic hydrocarbons (PAH). The carcinogenicity was examined with the subcutaneous test using 7000 mice in total. The amount of extract required was relatively small. Extracts from suspended matter with a BaP content of 0.37 to 1.1 microgram BaP brought about tumour rates in the range of 30%. On account of the results the following can be concluded: 1. The total extract of atmospheric particulates results in definite dose-response relationship, when the part of the compounds not belonging to the PAH is rather low. 2. The PAH fractions derived from the suspended matter collected in different cities show the same carcinogenic potency, when they are adjusted to the same BaP level by means of concentration or dilution. 3. The PAH bear the most important share with respect to the carcinogenic potency of an extract from suspended matter. 4. Numerous compounds (polar substances) which are not classed with the PAH are carcinogenic to some extent, partly they are able to inhibit the carcinogenic effect. 5. The dose-response relationship of BaP is strongly leveled off in general when all the substances of an extract are present. That means when the dose of an extract is low, the importance of BaP becomes less. Therefore a fixed ratio concerning the effect of BaP within an extract cannot be given. It has to be examined in particular, which PAH and non-PAH are necessary to analyse in order to describe the carcinogenic effect due to an extract from airborne particulates. Much more attention is to be payed to the polar substances.

Air Pollutants↗
PubMed1977

Neurobehavioral and systemic effects of longterm blood lead-elevation in rats. I. Discrimination learning and open field-behavior.

In order to assess neurobehavioral deficit subsequent to early low-level lead-exposure, Wistar-rats were prenatally Pb-exposed via their mothers, neonatally via their dams' milk, and later on via their diet containing lead acetate (745 mg Pb/kg diet). Blood-lead levels (PbB) of dams increased from 24.2-31.2 microgram-% during pregnancy and suckling-periods, those of offsprings were 26.6 microgram-% at about 16 days of age and 28.5 microgram-% at about 190 days of age. Between 100 and 200 days of age 40 male offsprings were subjected to behavioral testing, namely an open field-test and a visual discrimination-learning task. Two learning-tasks of different complexity, i.e. orientation- and size-discrimination, were used. Data of 20 lead-treated animals were compared with those of 20 age-matched controls. In the open-field test lead-fed animals were significantly more restless than controls; an increase of ambulation, rearing and grooming was observed. In the difficult learning-task, i.e. size discrimination, only the controls did learn the problem, whereas only one of the lead-group did; there was, however, no difference between lead- and control-animals for the easy task, i.e. orientation-discrimination. The observed effects, namely overreaction in the open field and a deficit of visual discrimination learning, may be interpreted in terms of lead-induced CNS-dysfunction. They clearly suggest that the "no-response level" for neurobehavioral damage in the rat, subsequent to early lead-exposure, must be assumed to be lower than 35 microgram/100 ml.

Animals↗
PubMed1977

[The influence of particulate matter and gaseous pollutants on the resistance against infectious diseases (author's transl)].

Groups of female NMRI-mice inhaled nine weeks 12.4 or 81.8 microgram Pb/m3 24 h per week, while other groups inhaled 0.3 mg NO2 + 5 mg flame soot/m3 or 5 mg NO2 + 0.3 mg flame soot/m3 for 45 h/week. Five animals of each group were randomly selected in weekly intervals and bacterial elimination determined 5 hours after inhaling a Serratia marcescens-aerosol. Bacteria in lung sections were determined by means of the "sandwich-method", using an anti-Serratia-serum and a FITC-loaded antirabbit-gammaglobuline. Inhalation of leadchloride caused a time and dose-dependent deterioration of bacterial elimination, which showed to be statistically significant already after three days of treatment with 81.8 microgram Pb/m3. A time dependent function between bacterial elimination and exposure could not be shown under treatment of the mixed pollutants NO2 and flame soot, although the lung clearance was deteriorated especially in the group treated with 5 mg NO2 + 0.3 mg flame-soot/m3. The experiments give evidence that lead exhibits a cyto-toxic effect on alveolar macrophages while the combined pollutants NO2 and flame-soot exhibit their adverse effect on the mucociliary-system. Nitrogen dioxide is shown to be a more hazardous pollutant than flame-soot within the given combination.

Animals↗
PubMed1976

[The effect produced by fine-dust extracts on cells in vitro, with particular regard to cancerogenic components (author's transl)].

Airborne dust is toxic for cells cultured in vitro and able to transform these cells to cancerous. The effect of extracts from atmospheric dust has been investigated. The dust samples were extracted by means of DMSO alone or in combination acetone-DMSO. Dosage of the extract was done according to its benzo(a)pyrene content (mug/ml medium). Dust extract with a concentration of 1 mug benzo(a)pyrene/ml exerted a toxic effect upon mouse macrophages (cell line IC-21) and human lymphocytes after stimulation. The degree of toxicity was estimated from the percentage of damaged cells seen in the dye exclusion test and from the amount of lactate dehydrogenase and lactate released into the medium in the case of macrophages. In the case of lymphocytes the degree of toxicity was estimated from the extent of inhibition of DNA synthesis. In the carcinogenicity test, hamster kidney cells were first treated with the extract and then incubated with Simian Virus (SV-)40. Treatment of the cell cultures with extract from airborne dust in a concentration of 0.01 and 0.1 mug benzo(a)pyrene/ml clearly enhances the rate of transformation caused by SV 40.

Air Pollution↗
PubMed1975

[Investigations on the influence of NO2 and SO2 as well a combination of the two gases on the production of precipitating antibodies in guinea-pigs (author's transl)].

The influence of NO2 and SO2 or their combination on the production of precipitating antibodies was studied in guinea pigs. The gas concentration has been 10 mg/m3; the continuous exposure began 3 days before sensitization and lasted up to the testing date. Sensitization was done s.c. and i.m. with fresh chicken albumen plus complete Freund's adjuvans. Production of precipitating antibodies was tested by the double diffusion method of Ouchterlony. Moreover total protein content was measured and an immunelectrophoretic separation of the protein fractions was performed with polyvalent antiguinea pig serum. The statistical evaluation of the results has yielded no support in favour of an interaction of NO2 and SO2 or their combination in the concentration used on the formation of precipitating antibodies.

Animals↗