Immunotoxic effects of carbon tetrachloride--the effect on morphology and function of the immune system in mice.

Carbon tetrachloride (CCL4), a polychlorinated hydrocarbon, is known for its hepatotoxicity, neurotoxicity and skin irritancy. Some epidemiological studies suggest possible carcinogenicity of CCl4. This substance is still present in industrial wastes and in the environment. As the major role of the immune system is immunosurveillance against cancer, we decided to follow the morphological and functional changes of the immune system during acute and subchronic exposures to CCL4 in mice. Mice (A/PhJ) were exposed i.p. to 1.7 mmol CCl4/kg b.w./day administered in olive oil (total volume 0.2 ml), for 2, 7, 14, 23 days. We evaluated: morphology of thymus, spleen and peripheral lymph nodes, immunopathology (thymus and spleen weight, spleen cellularity, number of peripheral blood leukocytes), non-specific immunity (phagocytosis, NK activity), humoral immunity (number of PFC after SRBC immunization, LPS mitogen response), cell-mediated immunity (PHA, ConA mitogen response). Morphological examination showed significant activation of lymphoid tissues in T-cell dependent areas. B-cell areas were also activated, but the formation of active germinal centers in lymphatic follicles has not been observed. The natural immunity was affected in a time dependent manner. A slightly hepatotoxic dose of CCl4 had a significant stimulative effect on phagocytosis and natural killer activity when administered in short-term schedule ("acute exposure"). Subchronic administration of the same dose led to suppression of phagocytosis and Nk activity. Similarly, the lymphocyte response to non-specific mitogens was enhanced during short-term exposure and significantly impaired when CCl4 was administered in long-term schedule. Antigen specific immune response to SRBC was impaired immediately after short-term exposure to CCl4 which suggests that the substance might affect the immunoglobuline proteosynthesis at the cellular level.

Human urine certified reference material CZ 6010: creatinine and toluene metabolites (hippuric acid and o-cresol) and a benzene metabolite (phenol).

A reference material for the biological monitoring of occupational exposure to toluene, benzene and phenol was prepared. O-cresol and hippuric acid (metabolites of toluene) are used for the biological monitoring of occupational exposure to toluene. Phenol, a metabolite of benzene, is used for the biological monitoring of exposure to benzene, but phenol can of course also be used as an indicator of exposure to phenol as well. The reference material (RM) used for the determination of these metabolites was prepared by freeze-drying pooled urine samples obtained from healthy persons occupationally exposed to toluene and those taking part in an inhalation experiment. Tests for homogeneity and stability were performed by determining urine concentrations of o-cresol, hippuric acid, creatinine and phenol. To investigate the stability of the RM, the urinary concentrations of o-cresol and phenol were monitored for eighteen months using GC and HPLC, while those of hippuric acid and creatinine were followed for five and six years, respectively, using HPLC. Analysis of variance showed that the concentrations did not change. The certified concentration values (and their uncertainties) of the substances in this reference material (phenol concentration c=6.46+/-0.58 mg l(-1); o-cresol concentration c=1.17+/-0.15 mg l(-1); hippuric acid concentration c=1328+/-30 mg l(-1); creatinine concentration c=0.82+/-0.10 g l(-1)) were evaluated via the interactive statistical programme IPECA.

A rapid HPLC method for the determination of carboxylic acids in human urine using a monolithic column.

A rapid HPLC method for the determination of carboxylic acids in urine samples using a Chromolith Performance RP/18e 100/4.6 with Chromolith Guard Cartridge RP/18e 10/4.6 (Merck KgaA, Darmstadt, Germany) was developed. The method facilitates the simultaneous determination of aromatic hydrocarbon metabolites mandelic acid (MA) and phenylglyoxylic acid (PGA) from styrene and ethylbenzene, hippuric acid (HA) from toluene and 2-, 3-, 4-methylhippuric acids (MHA) from xylene. 3-hydroxybenzoic acid (3-HBA) was used as internal standard. A chromatographic run is completed within less than 5 min for styrene, ethylbenzene and toluene metabolites, and within 10 min for xylene metabolites. The detection limits are 9 mg L(-1) urine for MA, 1.25 mg L(-1) urine for PGA, 4.9 mg L(-1) urine for HA, 22 mg L(-1) urine for 2-MHA, and 18.5 mg L(-1) urine for 3-MHA. No significant differences of the MA, PGA and HA concentrations in human urine samples obtained by HPLC chromatography on LiChrosorb RP 18 and on Chromolith RP/18e columns were found. The results were evaluated by using ANOVA.

The effect of 110mAg on ceruloplasmin oxidase activity in rats.

The effect of single i.v. injection of 110mAgNO3 (0.183 mg Ag+ X kg-1 b.wt.) in rats on the ceruloplasmin oxidase activity (Cp) and copper serum concentration was studied. It was found that Cp activity in the serum decreased to 70% of the control value and simultaneously serum copper concentration decrease to 30% of the control level. In both cases the decrease was independent on the time elapsed after silver administration. Comparing these results with those reported recently in mice Cu deficit in the rat serum was approximately twice higher. This fact is considered to be an inter-species difference. The concentration of copper in the hepatic supernatant significantly decreased (to eight times from control value) after silver injection. Only less than 10% of the total amount of Ag found in whole liver was taken up to hepatic supernatant. GPC analysis of the supernatant (Sephadex G-75) revealed that no Ag-metallothionein fraction is present. On the basis of the results obtained it was concluded that the mechanism of silver inhibition of Cp oxidase activity remains still in question.

The effect of some chelating agents on the biliary and urinary excretion of manganese in rats.

The biliary excretion of manganese, in rats which have been loaded with manganese via their drinking water, can be significantly enhanced by the administration of the chelating agents: desferrioxamine (DSF), sodium bis(hydroxyethyl) dithiocarbamate (DEDTC), and sodium isonipecotamidedithiocarbamate (INADTC). The effect of these chelating agents on the urinary excretion of manganese was more complex and was found to be dependent upon the level of loading of manganese as well as the individual chelating agent. For animals with drinking water containing 400 mg/liter of manganese, the administration of the chelating agents led to a decrease in the sum of the biliary plus urinary manganese excretion. The results are of special interest in that they show that under some conditions the administration of chelating agents can lead to changes other than those expected.

Human urine certified reference material CZ 6009: creatinine, styrene metabolites (mandelic acid and phenylglyoxylic acid).

The reference material was prepared by freeze-drying pooled urine samples obtained from healthy persons occupationally exposed to styrene. The concentrations of mandelic acid (MA), phenylglyoxylic acid (PGA), and hippuric acid (HA) in urine were determined by three modes of high-performance liquid chromatography (HPLC). For isochronous stability testing the urinary mandelic acid and phenylglyoxylic acid concentrations were followed over a 24-month period for a preliminary batch by use of HPLC. No changes of the concentration values were found. The creatinine concentration was stable for more than five years. Standard Reference Material NIST 914a Creatinine was used for traceability purposes for creatinine. Pure chemicals MA and PGA were used for traceability purposes. Control material ClinChek-Urine Control (Recipe) was analyzed simultaneously. The mean values of MA and PGA compare well with the means and fall within the control range of control samples. Results from homogeneity, stability, and traceability testing were evaluated using the statistical program ANOVA. The certified values and their uncertainties were evaluated from the results of interlaboratory comparisons, and homogeneity and stability tests. The values are unweighed arithmetical averages of accepted results and their uncertainties are combined uncertainties (coverage factor=1).

The study of exposure to cadmium in the general population. II. Morbidity studies.

An epidemiological study was performed to assess whether environmental pollution by cadmium as found in cadmium polluted areas of CSFR (Pribram and Frýdek-Mistek) is associated with changes in biological indicators of renal dysfunction in non-occupationally exposed population groups. Polluted areas were chosen on the basis of existing sources of Cd emission. The city of Prague was selected as a control area. Environmental monitoring (Cd in air, dust fall and soil) did not confirm significant contamination of selected areas. It was found that Cd levels in urine (Cd-U) of inhabitants living in areas chosen as Cd-contaminated were significantly higher than in the control area. Differences in concentrations of Cd in blood (Cd-B) levels between individual areas were not significant. No significant differences between the study populations were noted in the urinary excretion of low molecular weight proteins (beta 2-microglobulin, retinol binding protein) and albuminuria. However, total proteinuria and aminoaciduria in persons living in Pribram area was significantly higher. This area suffers from combined contamination by cadmium and lead. In smokers of both sexes the Cd-B levels were significantly higher in all areas, no significant differences were found in Cd-U levels. However, it was found that in smokers there is higher percentage of persons excreting more than 0.9 micrograms Cd.g-1 creatinine in urine. Consumption of home-grown vegetable and fruit in Cd-polluted areas led to significantly higher levels of Cd-B and Cd-U and total proteinuria. The results of the study show that smoking and food seem to be the most important sources of Cd intake in non-occupationally exposed populations. In spite of the fact that environmental monitoring does not reveal a significant contamination of selected areas by Cd, Cd-U levels confirmed that population living in these areas is really exposed to Cd.