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PubMed1981

Tissue chromium exchange in the rat.

This study of chromium (Cr) exchange in the rat combined measurements of 51Cr distribution and tissue Cr content to permit an assessment of tissue Cr exchange under control conditions and during varied Cr intakes. Liver Cr was found to be 50 to 100% exchangeable whereas pancreas Cr was only 34% exchangeable. In kidney, the specific activity of 51Cr exceeded that of serum by more than 100%, indicating a complex type of exchange involving both a rapidly exchanging Cr pool and an "inner" Cr pool with "sink-like" characteristics. Chromium deprivation of moderate degree reduced serum Cr and tissue exchangeable Cr pools but did not change total tissue Cr, 51Cr distribution, or glucose tolerance. Chromium supplementation and Cr overload increased serum Cr and total, exchangeable, and nonexchangeable tissue Cr pools but did not alter 51Cr distribution. These results indicate that the merging of tracer techniques with tissue Cr analyses yields a more complete view of Cr exchange than 51Cr distribution alone. The data support the hypothesis that specific transport characteristics exist in tissues that may regulate the biological role of Cr.

Animals↗
PubMed1983

Sister chromatid exchanges in Chinese hamster V79 cells treated with the trivalent chromium compounds chromic chloride and chromic oxide.

The induction of sister chromatid exchanges (SCEs) in Chinese hamster V79 cells exposed to soluble CrCl3 and insoluble Cr2O3, compounds of trivalent chromium (Cr3+), was determined. Their ability to induce SCEs was compared with those of three hexavalent chromium (Cr6+) compounds: K2CrO4, Na2CrO4 and Na2Cr2O7. Both the delay in progression through the cell cycle induced by Cr3+ compounds and the SCE frequencies in the delayed cells were also evaluated. The exposure for 28 h to CrCl3 and Cr2O3 at concentrations of 9.7-39 micrograms and of 34-136 micrograms of Cr3+ per ml, respectively, induced a statistically significant (p less than 0.001) dose-dependent increase in SCEs up to 1.9-fold (CrCl3) and 4-fold (Cr2O3) over control levels. Compared with the effective concentrations of Cr6+ compounds, which produced up to 4-fold increase of SCEs, inducing concentrations of CrCl3 and Cr2O3 were 300- and 1000-fold higher in terms of chromium. By prolongation of treatment time up to 48 h, a progressive dose- and time-related enhancement in SCE frequencies induced by Cr3+ compounds in delayed cells was observed. Lower concentrations of Cr2O3, without effect after 28 h of treatment, induced an increase of SCEs by prolongation of exposure time.

Animals↗
PubMed1997

Chromic oxide inclusion in the diet does not affect glucose utilization or chromium retention by channel catfish, Ictalurus punctatus.

This study was conducted to determine if the level of dietary chromic oxide will affect glucose utilization and tissue chromium retention by channel catfish. Purified diets containing graded levels of supplemental chromic oxide (0, 50, 100, 200, 400, 1000, 5000 and 10,000 mg/kg diet) and glucose as the carbohydrate source were fed to channel catfish fingerlings for 10 wk. Another diet containing dextrin as the carbohydrate source and without chromic oxide supplementation was also fed and served as the control diet. Fish fed the dextrin diet had significantly (P < 0.05) greater weight gain, feed efficiency ratio and protein efficiency ratio but lower plasma glucose concentrations than fish fed the glucose diets irrespective of the level of chromic oxide supplementation. The growth performance and postprandial plasma glucose concentrations of channel catfish fed glucose diets supplemented with various chromic oxide levels were not significantly different. No obvious trends were observed in the whole-body composition of fish fed glucose diets containing various chromic oxide levels. Carbohydrate source or the level of dietary chromic oxide did not significantly affect chromium concentrations in the whole-fish carcass. These results suggest that the level of dietary chromic oxide had no significant effect on glucose utilization or chromium retention by channel catfish. It is suggested that chromic oxide is sufficiently inert to be used as an external marker in digestibility studies in channel catfish.

Animals↗
PubMed1991

Chromium and cholesterol-induced atherosclerosis in rabbits.

Thirty-three rabbits on a cholesterol-enriched diet were randomized into 6 groups and treated with daily injections of either water, 20 micrograms of potassium chromate or 1, 5, 10 or 20 micrograms of chromium chloride, respectively, for 135 days with a 2- to 10-fold increase in serum chromium. There was a marked reduction in the percentage of aortic intimal surface covered by plaque, in aortic weight and cholesterol content in the treated animals. Rabbits treated with 20 micrograms of chromium chloride showed a better response than those treated with either 10 or 20 micrograms of potassium chromate.

Animals↗
PubMed2001

Mechanisms of chromium toxicity, carcinogenicity and allergenicity: review of the literature from 1985 to 2000.

Laboratory and clinical reports about the pathogenesis of the carcinogenicity and allergenicity of chromium compounds published between 1985 and 2000 have been reviewed as a basis for consideration of the pathogenetic mechanisms involved. There is good evidence from the clinic and the laboratory that Cr[VI] is the ion responsible for most of the toxic actions, although much of the underlying molecular damage may be due to its intracellular reduction to the even more highly reactive and short-lived chemical species Cr[III] and Cr[V]. Exposure to Cr[VI] can result in various point mutations in DNA and to chromosomal damage, as well as to oxidative changes in proteins and to adduct formation. The relative importance of these effects of chromium ions and of the free oxidising radicals they may generate in the body in causing tumours and allergic sensitisation remain to be demonstrated. Biochemical studies of the DNA-damaging effects and of the pathogenesis of the allergic reactions to chromium ions have not kept up with advances in understanding of the molecular basis of the effects of other carcinogens and allergens.

Allergens↗
PubMed1983

Metal release from cobalt-chromium partial dentures in the mouth.

The amounts of cobalt and chromium released to the saliva in individuals wearing cobalt-chromium partial dentures have been measured. Saliva was collected during a 5-min period, both with and without dentures in the mouth, and the two samples compared. More than 80% of the 30 cases showed increased amounts of metals with the denture in the mouth. Newer and larger dentures liberated more than did older and smaller ones. The median increase in chromium was approximately twice that of cobalt.

Chromium↗
PubMed1992

A study of chromium, nickel and cobalt hypersensitivity.

Hypersensitivity reactions to chromium, nickel and cobalt were investigated in the preclinical, fourth year and fifth year students of the Dentistry Faculty of Marmara University, Türkiye. A Standard patch test was performed. Four patches were applied to the shoulder blades of the students. Three of them contained small amounts of 0.5% potassium chromate, 5% nickel sulphate and 1% cobalt chloride respectively. The fourth (control) patch was of petroleum jelly. Questionnaires were used to determine sex and history of any previous allergy to jewelry. After 48 hours, the patches were removed and results assessed. For each base metal, no statistically significant difference was found in the incidence of hypersensitivity reaction between the groups. Nor was there a significant difference in response found between metals, for all of the students tested. Although women were found to have a higher rate of nickel hypersensitivity than men, no such sex difference was found chromium and cobalt. No significant relationship was found between a history of allergy to jewelry and chromium hypersensitivity, however there was a significant difference for nickel and cobalt hypersensitivity. In confirmation of our tests, significant relationships were found between previous allergy histories and the respective patch test results.

Chromium↗
PubMed1978

Determination of chromium and cobalt in human serum by neutron activation analysis.

Confusion exists about the chromium and cobalt concentrations in the serum of healthy individuals. We determined these elements by neutron activation analysis. The samples were irradiated during 12 days at a flux of approximately 10(14) neutrons.cm-2.s-1. Chromium was selectively separated by distillation after the irradiation. We obtained the following values (mean +/- standard deviation): 0.160 +/- 0.083 mug/liter for chromium, and 0.108 +/- 0.060 mug/liter for cobalt.

Blood↗
PubMedDate not supplied

Chromium: friend or foe?

Chromium is an essential nutrient with many natural sources, but several investigators have presented evidence that healthy persons often have an inadequate intake of this metal. Advocates of its use as a dietary supplement believe that people with diabetes, lipoprotein abnormalities, and increased risk of cardiovascular disease may benefit from such supplementation. Others suggest a therapeutic role for chromium in obese people and in those who seek to improve their body composition for other reasons, but research provides little support for these uses. For the general public, current data do not warrant routine use of chromium supplements, whose risk-benefit function has not yet been adequately characterized.

Chromium↗
PubMed2004

Extraction and transport of chromium(VI) through a bulk liquid membrane containing triphenylphosphine.

The solvent extraction of chromium(VI) in chloroform, dichloromethane, dichloroethane and its transport through a chloroformic bulk liquid membrane from sulphuric acid solutions with the neutral extractant triphenylphosphine (TPP) were studied. It was highlighted that the TPP extractant is an interesting complexing and efficient carrier for transport of chromium(VI) as [(HTPP)HCr2O7] complex from a 2M sulphuric acid solutions. It has a high ability to concentrate the chromium(VI) in the receiving phase according to the Donnan equilibrium. The co-extraction and the co-transport of sulphuric acid is very low and has no effect on the transport efficiency. The transport rate depends mainly on the initial concentration of the extractant.

Biological Transport↗
PubMed1989

Urinary excretion of chromium in chromeplaters after discontinued exposure.

In a previous study [Lindberg and Vesterberg, 1983a], excretion of chromium in urine (U-Cr) in chromeplaters was proposed for biological monitoring of ongoing exposure. Published reports were found about the decline of U-Cr after discontinued exposure in welders working in chromium-alloyed stainless steel, but not in chromeplaters. In this study, half-times (t1/2) were calculated for ten chromeplaters over a weekend, and for 23 chromeplaters over 31 days vacation. The results suggest that the excretion of chromium can be approximated to a two-compartment model. Estimated from the median values, an initial rapid phase with an assumed t1/2 of 2-3 days is followed by a phase with a t1/2 of approximately a month. Differences between the decline of U-Cr in chromeplaters and welders are discussed.

Chromates↗
PubMed1990

Cross-shift and chronic effects of stainless-steel welding related to internal dosimetry of chromium and nickel.

Ninety welders from a stainless-steel fabricating plant were studied by pulmonary function tests and serum and urine chromium and nickel levels, cross-sectionally, and 31 were compared across a Monday shift. They had welded for a mean of 11 years, mean age was 44 years, and mean smoking duration was 20 years in 62 current smokers. Baseline spirometric tests were significantly reduced: FVC to 95.4 mean percentage of predicted (pop), FEV1 to 94.5 pop, FEF25-75 to 85.9 pop, and FEFR75-85 to 74.8 pop. Current smokers had greater reductions in flow rates and FVC than nonsmokers even after adjustment of their predicted values for the effects of duration of smoking. Neither alveolar volume at 104.3 pop nor diffusing capacity for carbon monoxide (single breath) at 98.5 pop was reduced. There were no significant changes in pulmonary function measurements across a Monday workshift in 31 welders, but in seven men who welded stainless steel, levels of serum chromium (Cr) rose 66% from 1.9 +/- 2.1 micrograms/liter and urinary Cr increased 22%. Serum nickel levels rose only 7%, although they were elevated before shift, 1.1 +/- 0.4 micrograms/liter (compared with 0.21 +/- 0.20 micrograms/liter in controls), and urinary nickel levels did not increase. Eleven years of welding had reduced vital capacities and expiratory flows. Monday stainless-steel welding raised the serum and urine chromium levels (measures of internal dosimetry for exposure) but did not decrease pulmonary function values.

Adult↗
PubMed2003

Cometabolism of Cr(VI) by Shewanella oneidensis MR-1 produces cell-associated reduced chromium and inhibits growth.

Microbial reduction is a promising strategy for chromium remediation, but the effects of competing electron acceptors are still poorly understood. We investigated chromate (Cr(VI)) reduction in batch cultures of Shewanella oneidensis MR-1 under aerobic and denitrifying conditions and in the absence of an additional electron acceptor. Growth and Cr(VI) removal patterns suggested a cometabolic reduction; in the absence of nitrate or oxygen, MR-1 reduced Cr(VI), but without any increase in viable cell counts and rates gradually decreased when cells were respiked. Only a small fraction (1.6%) of the electrons from lactate were transferred to Cr(VI). The 48-h transformation capacity (Tc) was 0.78 mg (15 micromoles) Cr(VI) reduced. [mg protein](-1) for high levels of Cr(VI) added as a single spike. For low levels of Cr(VI) added sequentially, Tc increased to 3.33 mg (64 micromoles) Cr(VI) reduced. [mg protein](-1), indicating that it is limited by toxicity at higher concentrations. During denitrification and aerobic growth, MR-1 reduced Cr(VI), with much faster rates under denitrifying conditions. Cr(VI) had no effect on nitrate reduction at 6 microM, was strongly inhibitory at 45 microM, and stopped nitrate reduction above 200 microM. Cr(VI) had no effect on aerobic growth at 60 microM, but severely inhibited growth above 150 microM. A factor that likely plays a role in Cr(VI) toxicity is intracellular reduced chromium. Transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) of denitrifying cells exposed to Cr(VI) showed reduced chromium precipitates both extracellularly on the cell surface and, for the first time, as electron-dense round globules inside cells.

Biodegradation, Environmental↗
PubMed2003

Capillary electrophoresis speciation of chromium in leather tanning liquor.

We present a method for the speciation of chromium by capillary electrophoresis. Cr(III) was complexed with diethylenetriaminepentaacetic acid (DTPA) to form a negatively charged complex. Using 20 mM phosphate buffer of pH 8 containing 0.5 mM tetradecyltrimethylammonium hydroxide (TTAOH) at a separation voltage of -15 kV, both forms of chromium CrDTPA(2-) and CrO(4) (2-) were separated in less than 6 min. Direct UV detection at 214 nm was used. The effect of the presence of interfering ions was investigated. The application of the developed method to speciation of chromium in tanning liquor is demonstrated. The obtained results have shown a good correlation with those of flame atomic absorbance spectrometry (FAAS), inductively coupled plasma-mass spectrometry (ICP-MS) and UV/VIS spectrophotometry.

Chromium↗
PubMed1979

[Chromium--its community hygienic importance].

The present contribution is a literature survey of the presentday knowledge of the chromium contamination of the biosphere. It gives an insight into the absorption mechanism, accumulation and toxicity of chromium in man, and deals with its tolerance. Preliminary investigations into the chromium distribution and burden in the territory of the GDR are presented.

Chromium↗
PubMed2004

Alimentary chromium, nickel, and selenium intake of adults in poland estimated by analysis and calculations using the duplicate portion technique.

Chromium, nickel, and selenium have been known to be essential for proper functioning of human organisms. Since the Polish data concerning their content in diets are scarce, the study was undertaken to examine the levels of these elements in daily food rations (DFRs) in adults from the Lublin region in 1990, 1993, 1997, 1998, and 2002. The aim was to compare the results obtained by the calculation technique based on the national database with those of the DFR chemical analysis. Moreover, the study was to determine quantitative shares of the individual food groups in the daily pool of the elements examined. Determinations of chromium and nickel were carried out using flame atomic absorption spectrometry. Selenium was evaluated by spectrophotometry and fluorometry. The daily intake of chromium, nickel, and selenium was found to be 60 microg-90 microg, 124 microg-166 microg, and 54 microg-99 microg, respectively.

Adult↗
PubMedDate not supplied

Chromium-induced micronuclei in fish.

An investigation of the cytogenetic effects of chromium (Cr(VI) and Cr(III)) in Prussian carp (Carassius auratus gibelio) was made. For detecting cytogenetic damage, micronuclei induction in fish erythrocyte cells was employed. Fish were investigated 100 m above and 400 m below the discharge of leather waste products into the river Ljubljanica, and by exposing fish to three doses of chromium (Cr(VI) and Cr(III)) in the laboratory. The exposure of fish to various concentration levels (sub-lethal) of chromium under laboratory and field conditions caused an increase in the frequency of micronuclei compared with the control groups.

Animals↗