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PubMed1997

Chromium and exercise training: effect on obese women.

Chromium supplementation may affect various risk factors for coronary artery disease (CAD) and non-insulin-dependent diabetes mellitus (NIDDM), including body weight and composition, basal plasma hormone and substrate levels, and response to an oral glucose load. This study examined the effects of chromium supplementation (400 micrograms.d-1), with or without exercise training, on these risk factors in young, obese women. Chromium picolinate supplementation resulted in significant weight gain in this population, while exercise training combined with chromium nicotinate supplementation resulted in significant weight loss and lowered the insulin response to an oral glucose load. We conclude that high levels of chromium picolinate supplementation are contraindicated for weight loss in young, obese women. Moreover, our results suggest that exercise training combined with chromium nicotinate supplementation may be more beneficial than exercise training alone for modification of certain CAD and NIDDM risk factors.

Adolescent↗

PubMedDate not supplied

Effect of chromium picolinate on histopathological alterations in STZ and neonatal STZ diabetic rats.

Earlier studies from our laboratory have indicated insulin sensitizing action of chromium picolinate as the mechanism of its anti-diabetic activity in experimental models of type I and type II diabetes. In the present investigation, we have evaluated the effects of chronic administration of chromium picolinate on the functional and histological alterations of streptozotocin (STZ)-induced diabetes in rats. Type I diabetes was induced by intravenous injection of STZ (40 mg/kg) in adult rats, whereas, type II diabetes was induced by intraperitoneal injection of STZ (90 mg/kg) in 2-day old rat pups which in adulthood develop abnormalities resembling type II diabetes. Chromium picolinate was administered at 8 microg/ml in drinking water for 6 weeks and was found to improve glucose tolerance and increase insulin sensitivity of STZ-diabetic rats. This treatment decrease elevated serum creatinine and urea levels as well as elevated serum levels of hepatic enzymes of both groups of diabetic rats. Histopathological studies of kidney and liver show decrease in the intensity and incidence of vacuolations, cellular infiltration and hypertrophy of STZ and nSTZ (neonatal STZ) diabetic rats. Chronic treatment with chromium picolinate however, did not alter the normal function or morphology of control rats. Chronic chromium picolinate at the therapeutic doses that improved glucose tolerance, was observed to have no hepatotoxic or nephrotoxic potential. It was rather found to improve renal and hepatic function and to reduce abnormalities associated with STZ-diabetes. Chromium picolinate could play an important role in the long term management of diabetes mellitus.

Animals↗

PubMed1997

Mortality among Welders Exposed to High and to Low Levels of Hexavalent Chromium and Followed for More Than 20 Years.

Hexavalent chromium particles are generated in the welding of stainless steel. A cohort consisting of 233 welders working on stainless steel and exposed to high levels of chromium was selected. According to an earlier survey, the hexavalent chromium exposures of such welders are often above 20 µg/m(3). Another cohort consisting of 208 railway track welders exposed to low levels of chromium was also selected. The participants of both cohorts had welded for at least five years between 1950 and 1965 and were followed for mortality until December 1992. Among the welders exposed to high levels of chromium, six deaths due to pulmonary tumors occurred. This number is higher than the two deaths that occurred among the welders exposed to low levels of chromium and the corresponding mortality of the general population, but not significantly higher. Thus, exposure to stainless steel welding fumes might increase the incidence of pulmonary tumors.

Journal Article↗

PubMed2003

Antioxidant properties of chromium and zinc: in vivo effects on digestibility, lipid peroxidation, antioxidant vitamins, and some minerals under a low ambient temperature.

The effects of chromium (chromium picolinate, CrPic) and zinc (ZnSO(4)H(2)O) supplementation on serum concentrations of malondialdehyde (MDA) (an indicator of lipid peroxidation) and serum status of some antioxidant vitamins and minerals of laying hens (Hy-Line) reared at a low ambient temperature (6.8 degrees C) were evaluated. One hundred twenty laying hens (Hy-Line; 32 wk old) were divided into 4 groups, 30 hens per group. The hens were fed either a basal diet or the basal diet supplemented with either 0.4 mg Cr/kg of diet, 30 mg Zn/kg of diet, or 0.4 mg Cr plus 30 mg Zn/kg of diet. Digestibility of nutrients (dry matter [DM], organic matter [OM], crude protein [CP], and ether extract [EE]) increased by supplementation of chromium and zinc (p < 0.05). Supplemental chromium and zinc increased serum vitamins C and E but decreased MDA concentrations (p < 0.05). Additionally, supplemental chromium and zinc caused an increase in the serum concentrations of Fe, Zn, Mn, and Cr (p < 0.05). The present study showed that low ambient temperature causes detrimental effects on the digestibility of nutrients and antioxidant status and that such detrimental effects caused by low ambient temperature can be alleviated by chromium and zinc supplementation, particularly when Cr and Zn were simultaneously included into the diet. Data obtained in the present study suggest that such supplementation can be considered as a protective management practice in a diet of laying hens for alleviating negative effects of cold stress.

Acclimatization↗

PubMed1983

Monitoring exposure to chromic acid in chromeplating by measuring chromium in urine.

With personal air samplers, exposure to hexavalent chromium was measured in a group of eight chromeplaters during a period of 5 d; urine samples were collected at all times of urination for 7 d. The concentration of chromium in the urine increased from Monday morning to Tuesday afternoon and then remained constant within the group as a whole throughout the rest of the work week. In a large group of 90 chromeplaters exposure was measured for 1 d, and urine samples were collected before and after the workshift on Monday and Thursday of the same week. There was a correlation between the exposure and the concentration of chromium in postshift urine samples on Thursday (correlation coefficient 0.71). Concentrations of chromium in urine of less than or equal to 100 nmol/l indicate time-weighted average values of exposure of about or below 2 micrograms/m3. Below this exposure no severe damage to the nasal septum and no influence on lung function have been found. After the initial measuring of the airborne hexavalent chromium and the concentrations of chromium in the urine of exposed workers, urine analyses are recommended for follow-up controls.

Adolescent↗

PubMed1986

Release of corrosion products by F-75 cobalt base alloy in the rat. II: Morbidity apparently associated with chromium release in vivo: a 120-day rat study.

There is concern whether in vivo corrosion of chromium-cobalt alloys releases ions containing trivalent [Cr(III)] or hexavalent [Cr(VI)] chromium. The question arises from indications that Cr(VI) is far more biologically active than Cr(III). Using a previously developed microsphere implant model, specimens of F-75 chromium-cobalt-molybdenum alloy were implanted in rats for periods up to 120 days. Blood and urine were collected at intervals during the study. Significant postoperative serum and urine chromium concentration elevations were observed. In addition, weight gain inhibition, lung morbidity, and animal mortality, related to the implant surface area to animal body weight ratio (SA/BW), were observed. Comparison of measured chromium serum concentrations with those concentrations found by others to be biologically active in tissue culture studies strongly suggests the release of Cr(VI) in this study.

Animals↗

PubMed1997

Analytical methodology for biological monitoring of chromium.

Analytical aspects associated with biological and ambient monitoring are outlined with an emphasis on processing samples at very low concentrations and optimization of analytical methods. Verification of chromium determination in body fluids by means of "Round Robin" tests is discussed. In addition, an approach for indirect valency discrimination of chromium species relevant in biological monitoring is presented. Application of voltammetry for model tests is described. This is aimed at studying the reaction of hexavalent chromium in human plasma. As a result, a natural reducing capacity of plasma of up to 2 ppm chromium(VI) was detected and quantified as an individual biological index. Furthermore, the effect of ascorbic acid on the reduction of chromium(VI) in plasma is demonstrated and quantitative bases for therapy in cases of accidental intoxication are discussed.

Animals↗

PubMed1979

Reduced chromium retention in patients with hemochromatosis, a possible basis of hemochromatotic diabetes.

Chromium (III) has recently been shown to be an essential trace mineral in rats, being required for normal function of insulin in controlling glucose metabolism. Chromium is transported in the body bound to transferrin, where it binds competitively with iron. Hemochromatosis is an iron storage disease in humans characterized by highly saturated transferrin levels and sometimes by diabetes. We postulated that the diabetes may be due to exclusion of chromium by iron at metabolic binding sites. 51Cr(III) was administered i.v. to 5 normal males, 6 patients with hemochromatosis prior to therapeutic removal of iron, and 5 patients with varying levels of iron loading. The retention of 51Cr was measured with a whole-body counter for 8 mo and blood levels were measured for 40--80 days. Analysis of the whole-body retention curves revealed 3 exponential components with T1/2s of .56 days, 12.7 days, and 192 days; the blood curves had 4 components with T1/2s of 13 min; 6.3 hr, 1.9 days, and 8.3 days. The T1/2s were not significantly different between the normals and patients. The coefficients of these components however, were significantly lower for the long T1/2 components in the iron-loaded patients, demonstrating reduced retention of 51Cr as postulated. Whether this reduced retention of chromium is causally related to diabetes in hemochromatosis and whether abnormal chromium metabolism is involved in endogenous diabetes, thus, becomes an important question for future study.

Adult↗

PubMed2005

Chromium recovery from chrome shaving generated in tanning process.

In this study, the chromium recovery conditions in the form of soluble chromate from chrome shaving (chromium-containing solid waste) by oxidation with air, oxygen and Na2O2 were investigated and basic Cr(III) sulphate solution using in the tanning was prepared from the chromate obtained. It has been determined that the oxidation agent is the most effective parameter affecting the chromate formation. While maximum oxidation yields in air and oxygen atmosphere at 850 degrees C were found to be 23.02 and 30.41%, respectively, the highest chromium recovery efficiency in the form of chromate (99.45%) occurred in the presence of eight times Na2O2 with respect to stoichiometric amount of chromium. The chromate generated in Na2O2 oxidation process where 99.45% of chromium in the chrome shaving can be recovered was leached with distilled water and pregnant chromate solution was prepared. The chromate ions in this solution were reduced by using Na2SO3 and Cr(III) sulphate solution was obtained.

Chromium↗

PubMed1987

Alveolar macrophage abnormalities in rabbits exposed to low concentrations of trivalent chromium.

Rabbits were exposed by inhalation to a trivalent chromium compound (Cr(NO3)3) at a mean chromium concentration of 0.6 or 2.3 mg/m3 for about 4 months, 5 days/week and 6 hr/day. Light microscopic examination of the lungs revealed that both chromium levels induced a nodular intraalveolar accumulation of enlarged macrophages with granular, eosinophilic cytoplasm. Some macrophages were multinucleated and some showed advanced degenerative changes with disruption of cellular borders and nuclear pyknosis. The changes were most prominent in rabbits exposed to the high concentration and were in some areas associated with a mild interstitial infiltration of lymphocytes, neutrophils, and eosinophils. Electron microscopic examination of macrophages lavaged from the lungs revealed numerous enlarged lysosomes with membranous structures, distinct rounded inclusions, which by X-ray microanalysis were found to contain high amounts of chromium, and increased numbers of laminated inclusions probably representing ingested surfactant. The number of macrophages with a smooth surface was significantly increased. The macrophages in the lung tissue showed the same changes and in addition nodules of multinucleated "giant" cells were found. Morphometric estimation of the volume density of the type II cells did not reveal any significant differences between controls and rabbits exposed to the high concentration of chromium. In spite of the elevated number of laminated structures in the macrophages the amounts of phosphatidylcholine and 1,2-dipalmitoylphosphatidylcholine were not significantly increased in the lung. This indicates a reduced catabolism of surfactant by the alveolar macrophages.

Animals↗

PubMed1997

Uptake and tissue distribution of chromium(III) in mice after a single intraperitoneal or subcutaneous administration.

The tissue levels of chromium were followed after single intraperitoneal or subcutaneous injection of 1 mmol CrCl3/kg body wt. in Swiss male mice. Blood levels were similar after both treatment modes, with half-lives of 31-41 h. Organs not directly exposed by i.p. treatment contained similar amounts in the two groups, with kidneys > lungs > heart > brain. However, after i.p. treatment peritoneal organs (liver, spleen, pancreas and testis) had 40- to 200-fold more chromium compared with s.c. Assay of subsurface liver tissue and of testes removed via the scrotum indicated infiltration of the organs, rather than surface adsorption, of peritoneal chromium. Relative chromium concentrations after i.p. treatment were liver > pancreas = spleen > testis and after s.c. liver > spleen > testis > pancreas. Thus, s.c. treatment with CrCl3 is as effective as i.p. in terms of absorption into the blood. Treatment i.p., leading to direct uptake into peritoneal organs, is an effective way to deliver high chromium doses to these organs, but does not model likely human exposure.

Animals↗

PubMed2003

Four-year study of cobalt and chromium blood levels in patients managed with two different metal-on-metal total hip replacements.

BACKGROUND: Metal-on-metal total hip prostheses will produce a certain amount of wear debris. This results in increased whole-blood metal levels, which may cause adverse effects. It is not known to what extent the problem has been overcome by advances in alloy technology. METHODS: In 259 patients who with total hip replacement, blood cobalt and chromium concentrations were measured with atomic absorption spectrophotometry over a period of four years after arthroplasty. Of the patients enrolled in the study, 131 had been managed with a METASUL cobalt-chromium alloy metal-on-metal bearing combination, while 128 had been given a SIKOMET-SM21 cobalt-chromium alloy metal-on-metal combination. The control group consisted of 31 age- and gender-matched subjects. RESULTS: Compared with the controls, all the patients had higher cobalt and chromium levels. Cobalt concentrations were up to 50 times higher, while chromium concentrations were up to 100 times higher. CONCLUSIONS: Both systems showed evidence, in the whole-blood samples, of wear debris production by the implants. Therefore, patients managed with metal-on-metal bearing combinations should be carefully monitored in order to ensure that any local or systemic complications are detected early on.

Arthroplasty, Replacement, Hip↗

PubMed2001

Combining Drosophila melanogaster somatic-mutation-recombination and electron-spin-resonance-spectroscopy data to interpret epidemiologic observations on chromium carcinogenicity.

Lung cancers are significantly increased among workers exposed to chromate (Cr6+, Cr3+), chromium pigments (Cr6+) and chromium plating (Cr6+). Chromium lung burdens and cancer risk increase proportionately with duration of employment at long latencies. However, this epidemiologic information alone is insufficient in determining whether Cr6+ or Cr3+ are equally important in causing cancer. We have attempted to combine epidemiologic data with data from the Drosophila melanogaster somatic-mutation-recombination-test and from the in vitro electron-spin-resonance spectroscopy study to demonstrate that following somatic recombination plays a more important role than somatic mutation in chromium carcinogenesis. Cr4+ is more important than Cr5+ or Cr6+ in inducing somatic recombination while Cr6+ produces more and bigger clones than Cr4+ in somatic mutation. Cr3+ produces negative results in this fruit-fly wing-spot-assay. When the larvae and flies exposed to Cr6+ and Cr4+ are examined by ESR, only Cr5+ and Cr3+ are found. Thermodynamic parameters deltaE, deltaH, and deltaS are also estimated from these latter experiments to explain the relative importance of Cr6+, Cr4+, Cr3+ in chromium carcinogenesis among exposed industrial workers.

Animals↗

PubMed1988

[Morphological studies of the effect of chromium-III-chloride on the islet cell organ in rats under the conditions of high and low fat diets].

It is well known, that the glucose tolerance factor amplifies the peripheral action of insulin. This factor contains trivalent chromium. This investigation deals with the influence of trivalent chromium on morphometric and histological parameters of pancreatic islets of wistar rats. Animals were given chromium-III-chloride for 8 weeks (perorally, daily 15 ppm or 3 ppm) under conditions of high (HFD) and low (LFD) fat diet. Staining of pancreatic slices was performed with Victoria blue and acid Fuchsin. The relative volume density of the endocrine cells was obtained as the ratio of the number of islet cells to the number of exocrine pancreatic cells. The statistical evaluation was performed by using Students t-test. In HFD animals (n = 12) chromium supplementation caused an increase by 41% of volume of islets compared to HFD controls. A lot of small islets were found, which may be newly formed. Moreover, polynesia and hyperplasia of islets were observed. LFD animals (n = 12) do not show any morphometric changes in comparison with LED controls; but macronesia, micronesia and polynesia of islets were observed. In conclusion we suggest, that under special conditions trivalent chromium has growth stimulatory effects on the endocrine pancreas.

Animal Feed↗

PubMed1996

Inhibition of T and B cell proliferation by titanium, cobalt, and chromium: role of IL-2 and IL-6.

The mechanism by which an increased risk of prosthetic infection is induced in patients with total joint arthroplasties is poorly understood. The adverse effects of metallic corrosion products of a prosthesis on host defense mechanisms, particularly immune response and release of immunoregulatory cytokines, remain largely unknown. Titanium, cobalt, and chromium are the materials most often used for joint implantation. Therefore, this study was aimed at investigating the cytotoxicity of titanium, cobalt, and chromium and whether these metals affect T and B cell proliferation and the release of cytokines by human peripheral blood mononuclear cells (PBMC) in vitro. Metal cytotoxicity was not observed judging by cell viability and cell injury after PBMC was extensively exposed to the metals. Phytohemagglutinin (PHA)-induced T cell proliferation and lipopolysaccharide-induced B cell proliferation were significantly inhibited by titanium, chromium, and cobalt. The release of IL-2 and IL-6 by PHA-stimulated PBMC was significantly inhibited by titanium, chromium, and cobalt. Titanium did not alter IFN-gamma production, whereas chromium and cobalt significantly reduced IFN-gamma release by PHA-stimulated PBMC. The addition of IL-2 and IL-6 significantly restored the metal-induced inhibition of T cell and B cell proliferation, respectively. This study sheds light on how the metals impair immune response and cytokine release, suggesting that patients with an extensive exposure to the metals may develop immune dysfunctions. The compromised immune response induced by the metals might significantly contribute to an increased risk of infection in patients with joint prostheses.

B-Lymphocytes↗

PubMed2000

Use of an automated chromium reduction system for hydrogen isotope ratio analysis of physiological fluids applied to doubly labeled water analysis.

The doubly labeled water method is commonly used to measure total energy expenditure in free-living subjects. The method, however, requires accurate and precise deuterium abundance determinations, which can be laborious. The aim of this study was to evaluate a fully automated, high-throughput, chromium reduction technique for the measurement of deuterium abundances in physiological fluids. The chromium technique was compared with an off-line zinc bomb reduction technique and also subjected to test-retest analysis. Analysis of international water standards demonstrated that the chromium technique was accurate and had a within-day precision of <1 per thousand. Addition of organic matter to water samples demonstrated that the technique was sensitive to interference at levels between 2 and 5 g l(-1). Physiological samples could be analyzed without this interference, plasma by 10000 Da exclusion filtration, saliva by sedimentation and urine by decolorizing with carbon black. Chromium reduction of urine specimens from doubly labeled water studies indicated no bias relative to zinc reduction with a mean difference in calculated energy expenditure of -0.2 +/- 3.9%. Blinded reanalysis of urine specimens from a second doubly labeled water study demonstrated a test-retest coefficient of variation of 4%. The chromium reduction method was found to be a rapid, accurate and precise method for the analysis of urine specimens from doubly labeled water.

Chromium↗

PubMed2002

Continuing exposure to hexavalent chromium, a known lung carcinogen: an analysis of OSHA compliance inspections, 1990-2000.

BACKGROUND: Hexavalent chromium is widely recognized to be a lung carcinogen. However, the U.S. Occupational Safety and Health Administration (OSHA) has failed to reduce the permissible exposure limit (PEL), despite having acknowledged in 1994 that the current limit is too high. In 1993, Public Citizen and the Paper, Allied-Industrial, Chemical and Energy Workers International Union (PACE) petitioned to lower the PEL from the current 100 microg/m(3) to 0.5 microg/m(3) as an 8-hr time-weighted average (TWA). METHODS: To assess industry compliance with the current PEL, and to determine the feasibility of achieving the proposed lower limit of 0.5 microg/m(3), we conducted a secondary data analysis of OSHA's Integrated Management Information System (IMIS) database. This database contains 813 measurements of hexavalent chromium exposure from inspections performed during the years 1990-2000. RESULTS: There was a statistically significant decline in the annual number of measurements over the study period from 127 in 1990 to 67 in 2000 (F = 0.0009; linear regression). The median TWA measurement was 10 microg/m(3) (range: 0.01-13,960 microg/m(3)) and the median ceiling measurement was 40.5 microg/m(3) (range: 0.25-25,000 microg/m(3)). Neither median TWA nor median ceiling exposures (if hexavalent chromium was detected) declined significantly during the study period (F = 0.065 and 0.57, respectively). Overall, 13.7% of TWA measurements were at or below the Public Citizen/PACE proposed standard; 65.0% were between the Public Citizen/PACE proposal and the current OSHA PEL; and 21.3% exceeded the OSHA PEL. Compared to OSHA measurements, state measurements were less likely to detect hexavalent chromium (40.2% vs. 52.1%; P = 0.0007; chi-square) and less likely to issue any citation (9.3% vs. 19.1%; P = 0.0003), including citations for overexposure if the exposure exceeded the PEL (54.8% vs. 78.8%; P = 0.012). CONCLUSIONS: U.S. workers continue to be exposed to dangerously high hexavalent chromium levels, but low exposure levels were found in some industries. Further investigations should examine whether state plans provide weaker enforcement than federal OSHA.

Carcinogens, Environmental↗

PubMed2000

Is chromium a trace essential metal?

If chromium is an essential metal it must have a specific role in an enzyme or cofactor, and a deficiency should produce a disease or impairment of function. To date, no chromium-containing glucose tolerance factor has been characterized, the purpose of the low-molecular-weight chromium-binding protein is questionable, and no direct interaction between chromium and insulin has been found. Furthermore, chromium3+ is treated like the toxic metals arsenic, cadmium, lead and mercury in animals. Chromium3+ may be involved in chromium6+-induced cancers because chromium6+ is converted to chromium3+ in vivo, and chromium3+ is genotoxic and mutagenic. Although there is no direct evidence of chromium deficiencies in humans, dietary supplements exist to provide supraphysiological doses of absorbable chromium3+. Chromium3+ may act clinically by interfering with iron absorption, decreasing the high iron stores that are linked to diabetes and heart disease. If so, this would make chromium3+ a pharmacological agent, not an essential metal.

Animals↗