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At least 1,333 records · Page 74Linked to original sources
PubMed1999

[Studies on male reproductive toxicity caused by hexavalent chromium].

OBJECTIVE: To study male reproductive toxicity caused by hexavalent chromium (Cr(VI +)). METHODS: Morphology of semen and spermatozoa was observed and chromium level in blood, chromium and zinc level in sperm plasma, leuteinizing hormone (LH) and follicle stimulating hormone (FSH) levels in serum were determined for male workers exposed to (Cr(VI +)) (CrO(3)X = 0.0195 mg/m(3)) with occupational epidemiologic investigation and laboratory analysis. RESULTS: For the exposed workers, their seminal counting was (52.21 +/- 45.51) x 10(9)/L, and zinc level in seminal plasma (4,811.85 +/- 1,401.88) micromol/L, significantly lower than those in controls (88.96 +/- 74.82) x 10(9)/L and (5 718.49 +/- 2 827.90) micromol/L, respectively, P < 0.05. Serum FSH was (7.34 +/- 6.88) IU/L in the exposed groups, significantly higher than that of controls (2.41 +/- 1.69) IU/L, P < 0.01. There were no significant difference in semen volume, semen liquefaction time, prevalence of teratospermia, serum Cr(VI +) and LH level in seminal plasma between exposed group and control group (P > 0.05). Prevalence of teratospermia was 0.24 +/- 0.09, and serum LH and FSH were (7.94 +/- 2.67) IU/L and FSH (9.33 +/- 6.47) IU/L, respectively, in workers exposed to high concentration of Cr(VI +) (CrO(3)X = 0.2351 mg/m(3)) significantly higher than those exposed to lower concentration of Cr(VI +) (CrO(3)X = 0.0172 mg/m(3)), with 0.17 +/- 0.06 of prevalence of teratospermia, (5.05 +/- 3.05) IU/L of LH, and (3.74 +/- 3.04) IU/L of FSH, respectively (P < 0.05). CONCLUSION: The results suggested that damage to convoluted seminiferous tubules epithelium, reduction of spermatozoa formation and increase in prevalence of teratospermia could be caused by exposure to certain concentration of Cr(VI +).

Adult↗
PubMed2000

The flexibility of titanium clasps compared with cobalt-chromium clasps.

Retention of a partial denture depends on the amount of undercut engaged on an abutment tooth and the flexibility of the clasp. Flexibility is influenced by clasp length and the denture base material. Titanium clasps are purported to have greater flexibility than cobalt-chromium cast clasps which should enable them to engage deeper undercuts or be used where shorter clasp arms are needed such as on premolar teeth. This study investigated the flexibility of cast titanium clasps with three commonly used cobalt-chromium clasps through comparative measurements of their tip deflections and yield strengths. The results showed that the titanium clasps were significantly (P < 0.05) more flexible than the cobalt-chromium clasps. However, all four materials were found to be flexible enough to engage an undercut of 0.25 mm without exceeding their yield strengths.

Chromium Alloys↗
PubMed2003

Evidence of hexavalent chromium ingestion.

We describe the application of histochemical demonstration of chromium in a case of fatal ingestion of potassium dichromate in a suicide attempt. Using 2-(8-quinolylazo)-4,5-di-p-tolylimidazole (QTI), we could demonstrate chromium in the erythrocyte of the victim, in situ. This finding provides a means of proving the hexavalent chromium ingestion.

Azo Compounds↗
PubMed2002

Removal of hexavalent chromium from aqueous solutions by adsorption on coal char.

The ability of Coal char, a waste product obtained after the reduction of iron ore, to remove hexavalent chromium from aqueous solutions by adsorption has been studied. The effects of pH, temperature, concentration of hexavalent chromium and coal char were investigated. Under ambient temperature and pH condition removal efficiency to the extent of more than 70 per cent has been achieved. The rate process follows first order kinetics with respect to hexavalent chromium concentrations. Thermodynamic parameters and adsorption results have been studied. Recycling efficiency of the coal char was also determined.

Carcinogens, Environmental↗
PubMed2003

Spectrophotometric studies on the investigation of chromium in environmental samples.

Isothipendyl hydrochloride is proposed as a sensitive and selective reagent for the rapid spectrophotometric determination of chromium(VI). The reagent instantaneously gives a red coloured species on reaction with chromium(VI) in phosphoric acid medium which exhibits maximum absorbance at 510 nm with Sandell's sensitivity of 2.28 ng cm(-2). Beer's law is valid over the concentraction range of 0.1-1.9 mg/l with an optimum concentration range of 0.2-1.7 mg/l. The method has been successfully applied to the analysis of chromium in environmental samples.

Carcinogens, Environmental↗
PubMed2003

Chromium (III) produces distinct type of cell death in cultured cells.

Chromium acetate hydroxide is a chemical form of trivalent chromium (Cr III) originating from industrial processes. Although considered relatively nontoxic, upon longer treatment intervals it may cause irreversible cellular damage culminating in cell death. In our present work we have attempted to analyze some of the mechanisms whereby this chemical inflicts damage while focusing on the final observed endpoints. We report that 1 mM chromium acetate hydroxide is during weeks lasting treatment capable of injuring the plasma membrane of Hep-2 cells, which in turn becomes permeable to Cr (III) ions. Analyses of several markers of cellular damage; i.e. mitochondrial activity, nuclear integrity and oxidative stress have shown that tested compound interacts directly with subcellular organelles and upon tested concentration and time induces distinct type of cell death bearing features of apoptosis and necrosis.

Apoptosis↗
PubMed1992

Aluminium, chromium and manganese detoxification mechanisms in Pseudomonas syringae: an X-ray fluorescence study.

Pseudomonas syringae cultured in a defined citrate medium supplemented with 1 mM aluminium, chromium and manganese, respectively, appeared to elicit disparate biochemical responses. At the stationary phase of growth aluminium was predominantly present as an insoluble residue. Although virtually none of this metallic element was detected in the supernatant, the bacterial cells appeared to contain some aluminium. Following the initial uptake of chromium the microbe secreted the metal in the supernatant. Only a small fraction of the chromium was localised in the bacterial cells; 91% manganese was biotransformed into an insoluble pellet. No citrate was detected in the exocellular fluid at cessation of cellular growth.

Aluminum↗
PubMed1978

Comparative toxicity of trivalent and hexavalent chromium to rabbits. III. Biochemical and histological changes in testicular tissue.

The administration of trivalent and hexavalent chromium compounds produced inhibition of the activity of succinic dehydrogenase, adenosine triphosphatase and acid phosphattase accompanied by cellular degeneration with complete absence of spermatocytes in the testis of rabbits. The biochemical and histological changes were more marked in the animals treated with the trivalent chromium than those exposed to hexavalent chromium and were progressive with the duration of exposure.

Acid Phosphatase↗
PubMed2004

[The role of chromium in cell biology and medicine].

Chromium (Cr3+) is an essential trace element for animals and humans. Its deficiency in organisms causes e.g. disturbances of carbohydrate and lipid metabolism, hypoglycemia, impaired glucose tolerance, elevated cholesterol and triglycerides in blood, but a decrease in HDL-cholesterol. It plays an important role in insulin-receptor activation. In the literature, antioxidative and anti-diabetic effects of chromium were also described. An excess of trivalent chromium can act as a prooxidant.

Antioxidants↗
PubMedDate not supplied

[Selection and properties of mutant yeast Pichia guilliermondii strains resistant to chromium (VI)].

Yeast Pichia guilliermondii strains L3 and L2, exposed to UV mutagenesis, produced over 80 mutants capable of growing on media containing 1.5 mM bichromate (Cr(VI)). The mutations making the strains resistant to Cr(VI) were dominant or semidominant. The mutants varied in Cr(VI) resistance, the degree of chromium accumulation in the cells (from 0.1 to 11.6 mg/g dry cells), and the degree of Cr(VI) reduction (from 50% to complete disappearance of bichromate from the culture liquid). Chromium accumulation in mutant cells depended on medium composition, Cr(VI) concentration, and the time of exposure to Cr(VI). The resistance to bichromate can be caused by various reasons: decrease in chromium absorption, altered ability to reduce Nr(VI), or damage of sulfate transport mechanisms.

Chromium↗
PubMed2005

Lung cancer in relation to occupational and environmental chromium exposure and smoking.

The increased occurrence of lung cancer in residents of Dolny Kubin, the North-Slovakia district with ferrochromium industry, compared to the general population of Slovakia, led us to the study assessing influence of the occupational and environmantal exposure to chromium on the lung cancer incidence, respecting also the risk coming from cigarette smoking. Residents of Dolny Kubin district with the diagnosed lung cancer in 1984-1999 were involved in the study. The occurrence of lung cancer was significantly higher in people working in ferrochromium industry. The age at the onset of the disease in people exposed to chromium was by 5.5 years lower than in non-exposed. Smoking was an important risk factor, which has been proved particularly in non-exposed group where 62% were smokers and the onset of the lung cancer in them occured about 3.4 years earlier than in non-smokers. In exposed groups, no significant effect of smoking was found. We can conclude, that occupational exposure to chromium was identified as the main risk factor of lung cancer in Dolny Kubin district even overlaying effect of smoking.

Chromium↗
PubMed2005

Chromium in tannery industry effluent and its effect on plant metabolism and growth.

Different dilution levels of tannery treated effluent and their corresponding concentration of chromium (Cr6+) were studied in a petridish culture experiment on seed germination and seedling growth in radish (Raphanus sativus L). The different concentrations of Cr6+ (2, 5 and 10 ppm) and treated tannery effluent (10, 25 and 50%) showed reduction in seedling growth and related enzymatic activities with increase in concentration of Cr6+ in treatments and effluent both. The low concentration of chromium (2 ppm) and effluent dilution (10%) showed significant growth reduction separately. At this concentration of chromium and effluent dilution chlorophyll content, amylase, catalase and protein contents remained unchanged while with increase in Cr6+ concentration (>2ppm) and effluent dilution (> 10%) in treatments showed growth inhibitory effects.

Amylases↗
PubMedDate not supplied

Evaluation of genotoxic potential of chromium (VI) in Channa punctata fish in terms of chromosomal aberrations.

Chromium, a widely recognized carcinogenic, mutagenic and redox active metal, is released into aquatic environments by electroplating, tannery and textile industries. Elevated concentrations in sediments and interstitial waters are well documented. Fishes dwelling in chromium waste infested waters are presumed to be affected by its deposits. To evaluate the genotoxic potential of chromium [Cr(VI)] on aquatic bio-system, bottom feeding fishes, Channa punctata, as model fish, were exposed to [Cr(VI)]. The chromosomal aberration test (CAT) was used as biomarker of [Cr(VI)] induced toxicity. The fish were divided into three groups:Group I non-treated controls; group II positive controls, treated with an intra-muscular injection of mitomycin-C at 1 mg/kg body wt; group III exposed to a sublethal concentration (7.689 mg/l) of [Cr(VI)], dissolved in the water. For CAT estimation, short term static bioassays were conducted and samples were collected from the kidneys of fish after 24, 48, 72, 96 and 168 hrs of exposure. The remarkable chromosomal aberrations recorded in the present investigation included chromatid breaks, chromosome breaks, chromatid deletions, fragments, acentric fragments, and ring and di-centric chromosomes, along with chromatid and chromosome gaps. A significant increase in chromosomal aberrations was observed after 72 hrs of [Cr(VI)] exposure. The present study, thus reveals that even for acute exposure, [Cr(VI)] is a genotoxic agent for C. punctata.

Animals↗
PubMed2006

[Studies on the nephrotoxicity of chromium compounds].

The toxicity of chromium in different valent are quite different. Cr (III) is a necessary trace element of human body, but excessive intake of Cr (III) may bring about health lesion. Cr (VI) is generally considered 1,000 times more toxic than Cr (III). Renal damge may happen when people contact or intake excessive chromium compounds. The renal function and the concentration of enzyme and protein may be changed. Kidney necrosis can happen in heavy cases. The metaboly of chromium compounds and its nephrotoxicity were reviewed in this paper.

Animals↗
PubMed1991

[Efficiency of various dental dust-aspiration-equipment regarding the treatment of cobalt-chromium alloys].

The comparative measuring of the dust-seizure-efficiency of aspirators is being carried out by a practice-related treatment of 5 cylindrical-shaped specimen made of a commercial cobalt-chromium-alloy with aluminum-oxide-grinding instruments and silicone-rubber-polishers. A small-filter-apparatus takes up the person related samplings of the occurring total-dust-amount, which is then being calculated by a gravimetric standard-measuring-procedure. The cobalt-chromium-dust-fraction in the total dust amount is determined through an x-ray-fluorescence-analysis. Workplace dust-aspiration-equipment of the firms KaVo, Freuding and Wassermann have been subjected to testing. The values of the efficiency of all aspirators turned out to be below the American Threshold Limit Value TLV-TWA (Threshold Limit Value-Time Weighted Average) of 0.5 mg/m3 for chromium. The strict TLV-TWA-value of 0.05 mg/m3 for cobalt it also--with the exception of the Freuding-aspirator A 84 with aspiration-tube--not exceeded.

Air Pollutants, Occupational↗
PubMed1990

The pattern design for evaluation of castability of nickel-chromium alloys.

To find a pattern design that would provide a higher degree of discrimination for castability of nickel-chromium alloys using a polyester sieve cloth pattern, four shaped patterns were chosen. The results as calculated by t-test indicated that patterns No. 2 and No. 3 can discriminate the castability of nickel-chromium alloys over almost the total range of the casting temperatures, but that pattern No. 3 is a better discriminator for the castability. Pattern No. 1 can only discriminate the castability at lower casting temperatures. Pattern No. 4 can only discriminate the castability at higher casting temperatures. The percent castability value calculated from the number of complete square segments and the areas of the four patterns are highly linear correlations, so it is reasonably accurate to calculate the castability only from counting the number of complete square segments. Beryllium-containing nickel-chromium alloy is more castable than non-beryllium-containing alloy and the higher casting temperatures appear to result in better castability.

Beryllium↗
PubMed1990

An outbreak of chromium ulcer in a manufacturing plant.

On May 23, 1989, managers of a manufacturing plant requested an investigation of an outbreak of hand ulceration and skin discoloration among workers. The plant has manufactured kitchen ranges for 30 years and employs approximately 633 hourly workers. The affected employees worked in the enamel department, where metallic range tops are coated with a "ground coat" or sprayed with an enamel coloring, and then baked in ovens at 1200F. Our evaluation included physical examinations, environmental sampling, and a questionnaire eliciting information concerning skin ulceration job history, demographics, and use of protective practices. We identified 10 enamel department workers (13.5%) who developed chromium ulcers between January 1st and June 30th, 1988. Ulcers were found on hands, forearms, periumbilical area and/or axillae. Within the enamel department, workers who handled conveyer hooks used to suspend range tops as they passed through the oven were at greatest risk (rate ratio (RR) = 12.44, 95% confidence interval (CI) = 2.90-53.35). Workers who wore gloves were protected from developing ulcers (RR = 0.08, 95% CI = 0.01-0.60). Normally, trivalent chromium (Cr+3) does not cause skin ulcers unless it is oxidized to hezavalent chromium Cr+6). The enamel used contained only Cr+3, not Cr+6, but analysis of hooks that had passed through the oven revealed Cr+6 on their surface. A mechanical failure of the oven resulted in the formation of sharp edges of the parts and consequently causing the abrasion of exposed skin. We believe Cr+3 was converted to Cr+6 during the baking process which associated with the mechanical failure of the oven causing this outbreak.

Age Factors↗
PubMed1990

[The effects of chromium on human health].

This is a review of studies dealing with the physiological role of chromium in the body and its harmful effects to human health. Trivalent chromium is discussed as a trace element essential to normal metabolism of hydrocarbons and to functioning of some enzymes. Toxic and carcinogenic effects of chromium due to occupational exposure, environmental pollution, food contamination and accidental poisoning are described.

Chromium↗