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PubMed1998

Bone marrow and liver mutagenesis in lacZ transgenic mice treated with hexavalent chromium.

The mutagenic effects of the hexavalent chromium compound K2CrO4 in lacZ transgenic mice (Muta Mouse) were investigated at two sampling times. K2CrO4 was administered intraperitoneally to five male mice per treatment group at a single dose of 40 mg/kg. The animals were sacrificed on days 1 and 7 after the treatment. Mutant frequencies in the bone marrow and liver were analyzed by the positive selection method using Escherichia coli C (galE-) strain and phenyl beta-D-galactoside. K2CrO4 induced a significant increase in mutant frequency in the bone marrow on day 1, but not on day 7 after the treatment. In the liver, on the other hand, a significant induction in the mutant frequency was seen on day 7, whereas no induction was observed on day 1. The reason for the different responses to the mutagenic activity of K2CrO4 between these organs may be related to their cell turnover rates. The mutations induced by K2CrO4 in the bone marrow may have occurred in more differentiated cells than stem cells, and the rapid proliferative activity may have caused a rapid decrease in mutated cells by day 7. These results suggest that experiments on mutagenesis should be done with more than one sampling point, a short expression time in addition to a longer one, so as to detect mutations induced in organ with high cell proliferation.

Animals↗
PubMed2003

Applications of high-field (W-band) EPR to M-M bonded units (M = Cr, Mo): the first confirmed oxidation of a Cr2 4+ paddlewheel complex to a stable isostructural Cr2 5+ product.

The EPR spectra of [Cr(2)[(PhN)(2)CN(CH(2))(4)](4)]PF(6) and [Mo(2)(TiPB)(4)]PF(6) (TiPB = anion of 2,4,6-triisopropylbenzoic acid) at W-band are shown to have g values significantly lower than 2.00 and exhibit parallel and perpendicular components (not resolved at X-band). Therefore the unpaired electrons of the M(2)(5+) units must reside on metal-based (not ligand-based) orbitals. Thus, the chromium compound must be considered as the first confirmed oxidation product of a Cr(2)(4+) paddlewheel complex comparable to the Mo(2)(5+) compounds.

Journal Article↗
PubMed2004

Preparation and characterization of the argentates: [Ag[P(CF(3))(2)](2)](-), [Ag[(micro-P(CF(3))(2))M(CO)(5)](2)](-) (M = Cr, W), and [Ag[(micro-P(C(6)F(5))(2))W(CO)(5)](2)](-): X-ray crystal structure of [K(18-crown-6)][Ag[(micro-P(CF(3))(2))Cr(CO)(5)](2)].

The first example of a mononuclear diphosphanidoargentate, bis[bis(trifluoromethyl)phosphanido]argentate, [Ag[P(CF(3))(2)](2)](-), is obtained via the reaction of HP(CF(3))(2) with [Ag(CN)(2)](-) and isolated as its [K(18-crown-6)] salt. When the cyclic phosphane (PCF(3))(4) is reacted with a slight excess of [K(18-crown-6)][Ag[P(CF(3))(2)](2)], selective insertion of one PCF(3) unit into each silver phosphorus bond is observed, which on the basis of NMR spectroscopic evidence suggests the [Ag[P(CF(3))P(CF(3))(2)](2)](-) ion. On treatment of the phosphane complexes [M(CO)(5)PH(CF(3))(2)] (M = Cr, W) with [K(18-crown-6)][Ag(CN)(2)], the analogous trinuclear argentates, [Ag[(micro-P(CF(3))(2))M(CO)(5)](2)](-), are formed. The chromium compound [K(18-crown-6)][Ag[(micro-P(CF(3))(2))Cr(CO)(5)](2)] crystallizes in a noncentrosymmetric space group Fdd2 (No. 43), a = 2970.2(6) pm, b = 1584.5(3) pm, c = 1787.0(4), V = 8.410(3) nm(3), Z = 8. The C(2) symmetric anion, [Ag[(micro-P(CF(3))(2))Cr(CO)(5)](2)](-), shows a nearly linear arrangement of the P-Ag-P unit. Although the bis(pentafluorophenyl)phosphanido compound [Ag[P(C(6)F(5))(2)](2)](-) has not been obtained so far, the synthesis of its trinuclear counterpart, [K(18-crown-6)][Ag[(micro-P(C(6)F(5))(2))W(CO)(5)](2)], was successful.

Journal Article↗
PubMed2006

Carbon dioxide fixation by an unprecedented hydroxo lead-chromium carbonyl complex: synthesis, reactivity, and theoretical calculations.

The novel hydroxo-bridged dimeric lead-chromium carbonyl complex [Et4N]2[{PbCr2(CO)10}2(mu-OH)2] ([Et4N]2[1]) was synthesized from the reaction of PbCl2 and Cr(CO)6 followed by metathesis with [Et4N]Br in a KOH/MeOH solution. The X-ray crystallographic structure shows that dianion 1 consists of two Pb{Cr(CO)5}2 units bridged by two hydroxo fragments in which the Pb atoms are further coordinated with two Cr(CO)5 groups, resulting in a distorted tetrahedral geometry. A CO2 molecule can insert itself into dianion 1 to form two new carbonate complexes, [Et(4)N]2[{PbCr2(CO)10}(CO3)] ([Et4N]2[2]) and [Et4N]2[{PbCr2(CO)10}2(CO3)] ([Et4N]2[3]), depending on the reaction conditions. In addition, complex 2 can be transformed into 3 in CH2Cl2 solution at an elevated temperature. While the carbonate group in dianion 2 is bonded to one Pb atom, which is coordinated with two Cr(CO)5 fragments, the carbonate group in 3 bridges the two Pb centers in a mu-1kappa2OO':2kappa2OO' fashion in which each Pb atom is further bonded to two Cr(CO)5 moieties. Complexes 2 and 3 can be converted back the hydroxo complex 1 under appropriate conditions. All three unprecedented lead-chromium compounds, 1-3, were fully characterized by spectroscopic methods and single-crystal X-ray diffraction analyses. The nature and formation of complexes 1-3 were also examined by molecular orbital calculations using the B3LYP method of the density functional theory.

Journal Article↗
PubMed1993

Glucose-dependent uptake of chromium in human and rat insulin-sensitive tissues.

1. This study was designed to investigate the influence of insulin and glucose on the distribution of trivalent chromium in human plasma and blood cells and in human and rat insulin-sensitive and -insensitive tissues. 2. Evidence is provided that, in the rat in vitro, a clear difference exists in chromium binding between insulin-sensitive and -insensitive tissues in that chromium binding is significantly enhanced by glucose in insulin-sensitive tissues. 3. Glucose-dependent association of chromium with human adipose tissue was blocked by inhibitors of glucose transport. 4. Addition of insulin slightly increased the response to glucose in muscle and reduced the response to glucose in adipose tissue; such effects were less marked than those seen in response to glucose alone. 5. The results of this study in vitro support the hypothesis that, in vivo, chromium translocates from the blood compartment to insulin-sensitive tissues.

Adipose Tissue↗
PubMed2001

Tissue contents and subcellular distribution of chromium and other trace metals in experimental diabetic rats after intravenous injection of Cr 50-enriched stable isotopic tracer solution.

In order to study the metabolism of essential trace elements in diabetics, we studied alloxan-diabetic rats for the distribution patterns of chromium (Cr), cobalt (Co), iron (Fe), selenium (Se), and zinc (Zn) in the liver, kidney, pancreas, and testes, as well as in the organ subcellular fractions. Normal rats were used as controls. Cr 50-enriched stable isotopic tracer solution was given by intravenous injection to avoid the difficulties of estimation of Cr status. Our data show that the concentrations of Zn in liver and kidney, of Co, Fe, and Zn in pancreas, and of Fe and Zn in testes of the diabetic rats were significantly higher than in the control rats. Nevertheless, the concentrations of Cr in pancreas, Fe in kidney, and Cr and Se in testes of the diabetic rats were significantly lower than in the controls. Furthermore, we observed significant alterations of element concentrations in subcellular fractions of various organs in the diabetic rats. These results suggest that changing hormone levels may interfere with the accumulation of some trace elements both in the organs and in the subcellular fractions of rats.

Animals↗
PubMed1987

[Use of 51-Cr2O3 and TiO2 as markers for the determination of passage rate and protein digestibility in rats].

In a tripartite experiment with five rats each the suitability of 51Cr2O3 and TiO2 as markers was tested for estimating the transit time and passage rate as well as the total protein digestibility and the proportion of endogenous nitrogen in the small intestine with very small samples. Both markers are suited for these tests because of their simple analysis, their high recovery rate (94...105% for 51Cr2O3; 98...105% for TiO2) and their quantitative excretion in faeces within 3 days. Depending on the level of crude fibre (5.1 resp. 9.4% of DM) the transit time was found to be 7...8 h for a commercial breeding feed and 5...6 h for this commercial feed +15% straw meal. After the application of a single doses, the marker excretion of 50% appeared within 10 +/- 1 h resp. 8 +/- 1 h, and after the 12th hour there were no significant differences at all. The apparent N-digestibilities estimated by the conventional or the 51Cr2O3 resp. TiO2 indicator method did not show any differences. The proportion of endogenous nitrogen at the end of the small intestine calculated on the basis of the indicator dilution method was 83 +/- 11% for 51Cr2O3 and 83 +/- 12% for TiO2.

Animals↗
PubMed1982

Increased incidence of chromosomal aberrations and sister chromatid exchanges in workers exposed to chromic acid (CrO3) in electroplating factories.

Chromosomal aberrations in cultured lymphocytes obtained from workers occupationally exposed to chromic acid (CrO3) were detected. Four separate groups of workers were examined, two of which were engaged in plating factories employing nickel in addition to chromium, and two coming from plating factories where only chromium was used. In the latter groups the frequency of sister chromatid exchanges (SCEs) were also detected in the cultured lymphocytes. A statistically significant increase of chromosomal aberrations, mostly of the chromosome-type, was found in two of the exposed groups of workers compared to the level observed in control donors. The frequency of SCEs in the exposed groups was higher than in controls, particularly in the factor which employed the younger workers. Besides the negative correlation with the age of workers, a positive correlation between the frequency of SCEs and the level of urinary chromium was found and such a correlation was strongly enchanced by smoking. The present data support the view that CrO3, like other soluble hexavalent chromium compounds, is genetically active in vivo.

Adult↗
PubMed2006

XRCC1 protects against particulate chromate-induced chromosome damage and cytotoxicity in Chinese hamster ovary cells.

Water-insoluble hexavalent chromium compounds are well-established human lung carcinogens. Lead chromate, a model insoluble Cr(VI) compound, induces DNA damage, chromosome aberrations, and dose-dependent cell death in human and Chinese hamster ovary (CHO) cells. The relationship between lead chromate-induced DNA damage and chromosome aberrations is unknown. Our study focus was on examining the role of XRCC1 in lead chromate-induced cytotoxicity and structural chromosomal aberrations in CHO cells. Three different cell lines were used: AA8 (parental), EM9 (XRCC1 mutant), and H9T3 (EM9 complemented with human XRCC1 gene). Cytotoxicity was significantly higher in EM9 cells when compared to AA8 and H9T3 cells, indicating that XRCC1 is important for protecting cells from lead chromate particles-induced cell death. The frequency of damaged metaphase cells was not affected by XRCC1 deficiency. However, the total amount of Cr(VI)-induced chromosome damage was exacerbated by XRCC1 deficiency, and the spectrum of damage changed dramatically. Chromatid and isochromatid lesions were the most prominent aberrations induced in all cell lines. XRCC1 was essential to reduce the formation of chromatid lesions, but not for isochromatid lesions. In addition, XRCC1 deficiency resulted in a dramatic increase in the number of chromatid exchanges, indicating that XRCC1 is involved in protection from lead chromate-induced chromosome instability.

Animals↗
PubMed2002

Cancer of the brain and nervous system and occupational exposures in Finnish women.

Occupational agents were evaluated for the risk of brain-nervous system cancer in a cohort of 413,877 Finnish women with blue-collar occupations in 1970. Observed and expected numbers of incident cases and the intensities of exposure to 25 agents were generated for 183 job titles from 1971 to 1995. Poisson regression models linked incidence and exposure data. Increased risks were found for medium/high intensities of iron (standardized incidence ratio [SIR], 2.15; 95% confidence interval [CI], 0.96 to 4.80), oil mist (1.95; 0.97 to 3.90), any chromium compounds (1.51; 0.85 to 2.67), electromagnetic fields (1.37; 0.98 to 2.10), aliphatic and alicyclic hydrocarbon compounds (1.34; 0.80 to 2.27), lead (1.27; 0.81 to 2.01), cadmium (1.26; 0.72 to 2.22), and aromatic hydrocarbon compounds (1.20; 0.71 to 2.03). Strengths of the study include fair number of cases, virtually complete case coverage, and a high-quality job exposure matrix. Ecological design and cross-sectional job assessment introduced exposure misclassification and tended to drive risk estimates toward unity.

Brain Neoplasms↗
PubMed2005

The European standard series in 9 European countries, 2002/2003 -- first results of the European Surveillance System on Contact Allergies.

Since January 2001, the European Surveillance System on Contact Allergies (ESSCA), supported by European Union funding (contract QLK4-CT-2001-00343), has started to collect patch-test data. This comprises a standardized clinical history and the patch-test results using the European standard series, from 17 centres in 9 European countries listed above. In 2002 and 2003, 10 511 patients' test results have been pooled and analysed. The anamnestic data partly reflect the subspecialties of some centres. The most common allergen was nickel sulfate (17.3%); however, large international variations were observed. The prevalence of contact allergy to Myroxylon pereirae resin (balsam of Peru) (5.8%) is coming close to the frequency found with the fragrance mix (6.4%). Regarding contact allergy to chromium compounds, different frequencies were noted in the 2 centres focused on occupational dermatitis (2.3% in the FIOH versus 7.4% in the Nofer Institute). These most likely reflect the beneficial effect of addition of ferrous sulfate in one, but not the other country. As differences may partly be due to different patch-test reading, standardization may need to be refined further. By providing post-marketing surveillance in the field of contact allergy, ESSCA will meet its objective of increased consumer safety across Europe.

Adult↗
PubMed1981

In vitro interactions of 51Cr in human red blood cells and hemolysates.

The intracellular distribution of radioactivity was studied in normal and sickle erythrocytes labeled with sodium 51Cr chromate. Both types of cells had a higher fraction of 51Cr bound to hemoglobin when labeled in the presence of ACD at a pH of 7.09 than when labeled in the presence of CPD at a pH of 5.96. Citrate at a pH of 5.96 or less entered the red blood cells and decreased the 51Cr binding hemoglobin. Binding of 51Cr to hemoglobin within the red cells was also reduced when the ATP and DPG levels in the red blood cells were elevated. Studies with hemoglobin solution showed that 51Cr binding to hemoglobin was influenced by 2,3-DPG, ATP and citrate.

Chlorides↗
PubMed1988

Irritant contact dermatitis and chrome-passivated metal.

An outbreak of hand dermatitis is reported amongst employees working on a new assembly line of an electronics factory. 24 out of 41 employees had signs of irritant contact dermatitis. The fingertips and the dorsal parts of the hands were especially affected. Mechanical factors in combination with zinc-chromium compounds from galvanised steel seemed to be responsible for the dermatitis and the dry skin. The use of an emollient solved the problem.

Chromates↗
PubMed1990

Occupational dermatoses and allergy to metals in Polish construction workers manufacturing prefabricated building units.

The incidence of dermatoses and allergy to metals (Cr, Co, Ni) was determined in 1782 workers exposed to cement, waste fly ash and asbestos cement. They were also exposed to reclaimed (used), mineral oils. Dermatitis was found in 23.6% of the subjects, and oil acne in 11.2%. Allergy to chromium was found in 23% of the subjects; the % of definitely positive patch test results (the total of positive +(+) and strongly positive +(+)+ was, however, 8.6%. Allergy to cobalt was found in 13.4% of the subjects examined (definite in 3.1%). Allergy to nickel was found in 2.7% of the subjects (definite in 1.1%). The risks of occurrence of occupational skin disease and allergy to metals in subjects exposed to ash were found to be lower than in subjects exposed to cement, and were similar to those in subjects exposed to asbestos cement. Overall chromium, cobalt and nickel contents in ash and asbestos were higher than in cement. Soluble chromium compound content in ash was lower than in cement from European countries and similar to that in American cement.

Acne Vulgaris↗
PubMed1990

Experience with a gastrointestinal marker (51CrCl3) in a combined study of ileal function using 75SeHCAT and 58CoB12 measured by whole body counting.

Introduction of a radioactive gastrointestinal marker (51CrCl3) into a combined study (75SeHCAT + 58CoB12) of ileal function by whole body counting has been undertaken. The technique was assessed in 23 subjects (15 patients with inflammatory bowel disease, six on non-steroidal anti-inflammatory drugs for rheumatoid arthritis, and two normal subjects). Mean (SD) 51CrCl3 retention was only 4.1 (6.0)% on day 4, and was similar on day 7 in subjects given a second dose of 51CrCl3 on day 4. Only one subject had more than 20% of 51CrCl3 retention after four days. A 51CrCl3 correction method adequately corrected for colonic hold up of 58CoB12, when compared with final equilibrium values of 58CoB12 retention. Use of the non-absorbed 58CoB12 fraction as a gastrointestinal marker gave good agreement with the 51CrCl3 method in correcting 75SeHCAT values. In all subjects studied, corrections for colonic retention of 75SeHCAT on day 4, were small (less than 7% of dose) and did not affect the assessment of any subject. In conclusion, an additional gastrointestinal marker such as 51CrCl3 is unnecessary in our combined study since that role can be effected, when indicated by the non-absorbed 58CoB12 fraction.

Adolescent↗
PubMed1984

Renal excretion of chromium-51 chloride in the dog.

To examine the renal handling of the trace element chromium, clearance studies were performed in pentobarbital sodium-anesthetized mongrel dogs following either gavage or intravenous administration of chromium-51(III) chloride. Ultrafilterable plasma chromium-51 comprised as much as 9-19% of the total plasma chromium-51 when the isotope was given by gavage but only 2-3% when given by intravenous infusion. The mean ratio of the clearance of ultrafilterable plasma chromium-51 to that of endogenous creatinine was approximately unity in all dogs [0.97 +/- 0.11 to 1.14 +/- 0.10 by gavage (n = 5); 0.84 +/- 0.05 to 0.97 +/- 0.05 intravenously (n = 4)]. Regardless of the route of administration, ultrafilterable plasma chromium-51 concentration and glomerular filtration rate appeared to be the primary determinants of renal chromium-51 excretion.

Animals↗