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Chromium-induced carcinoma in the nasal region. A report of four cases.

The carcinogenicity of chromium is well established in chromium-induced lung cancer. As of yet, however, there have been only few reports of head-and-neck cancer induced by chromium. We report four cases of carcinoma in the nasal region which seemed to be induced by chromium. All patients have worked at the same chromate factory for 19 to 32 years. The first patient has suffered from squamous cell carcinoma of the left nasal cavity, starting 11 years after his retirement. He received radiotherapy followed by surgery. A malignant fibrous histiocytoma occurred in his left upper gingiva in a previously irradiated region, 7 years after the previous treatment. Surgery and chemotherapy for palliation failed to control the tumour, and he eventually expired. The other three patients underwent lobectomy for lung cancer. In cases 2 and 3, the tumour occurred in the left nasal cavity six and ten years, respectively, each after the lobectomy. In case 4, the tumour arose from the nasopharynx 15 years after the lobectomy. These patients are alive and well without any sign of tumour. The presented cases seem to be induced by long-term exposure to chromium. We conclude that regular physical examination of chromate workers is mandatory for the early detection not only of lung cancer but also of head-and-neck cancer.

Aged↗

"Hot spots" of chromium accumulation at bifurcations of chromate workers' bronchi.

To investigate the mechanisms underlying respiratory tract carcinogenesis in chromate workers, we measured the concentration of chromium in samples of tissues from 50 bronchial bifurcations and other bronchial tissue obtained at autopsy, or during surgical procedures, from 9 exchromate workers known to be at risk of developing lung cancer. The mean duration of exposure was 21 years and the average time between cessation of exposure and death/surgery was 15 years. The area of the tissue samples was measured by image analysis and the chromium concentration determined by neutron activation analysis. Chromium concentrations ranged from 0.04 to 39 x 10(-10) g/microns tissue thickness/mm2 and in 80% of the cases the concentrations were greater at bifurcations than in neighboring epithelial tissue. The mean concentration ratios between bifurcations and adjacent areas were 1.5 (n = 1) in the trachea, 3.0 (n = 9) in the main bronchi, 3.6 (n = 22) in lobar bronchi, and 10.9 (n = 3) in subsegmental bronchi. Our results demonstrated long-term retention of chromium in the bronchial walls of chromate workers and also that chromium concentrations were higher at airway bifurcations than elsewhere, thus providing solid evidence for a deposition "hot spot" concept.

Aged↗

Cellular distribution of hexa and trivalent chromium in Pseudomonas aeruginosa.

Binding of Cr to P. aeruginosa whole cells increased with an increase in positive charge of the chromium complexes used. Distribution of Cr bound from aqueous solutions of potassium dichromate--a Cr(VI) salt and basic chromium sulphate (BCS)--a Cr(III) salt [used for tanning which has 25% of Cr2O3 on weight basis and is of 33% basicity (one hydroxyl/Cr atom)] was more in soluble fraction (protein and nucleic acids) than in insoluble fraction (lipids, polyphosphates, polysaccharides, lipopolysaccharides and mucopeptides). Electron spin resonance spectrum of the cells exposed to hexavalent chromium revealed the presence of Cr(III) ion demonstrating a reduction of the same by the Pseudomoas. The infrared spectra of chromium exposed cell envelopes support that protein carboxylic sites and proteins are involved in binding Cr(III) and predominantly lipids in Cr(VI). Bound chromium could be removed chemically and the cells could then be reused as a biosorbent.

Cell Fractionation↗

Effects of chromium and guar on sugar-induced hypertension in rats.

Ingestion of sugars (sucrose, fructose, glucose) by various rat strains is associated with perturbations in the glucose/insulin system and higher systolic blood pressure (SBP). The association suggests causality, because alterations in insulin metabolism have been found in essential hypertension and many experimental forms of hypertension. To test the hypothesis that sugar-induced SBP elevation is secondary to perturbed insulin metabolism, we examined in 2 experiments effects of chromium and guar, substances known to affect insulin metabolism, on SBP of Spontaneously Hypertensive Rats (SHR). In both studies, sucrose compared to starch ingestion caused significant elevation of SBP; but addition of 2 chromium nicotinate complexes and guar prevented development of sugar-induced SBP elevations. The basal, genetic hypertension of the SHR was not affected by either nutrient. An additional finding in the first study was that sugar-consuming SHR supplemented with chromium had greater BW and increased organ weight (kidney, spleen, and liver) than nonsupplemented SHR. Accordingly, we have shown that two different mechanisms known to ameliorate insulin perturbations, use of chromium and guar, prevent sugar-induced SBP elevations. Since essential hypertension may be due to insulin perturbations and high dose chromium supplementation seems nontoxic, this may prove to be a useful means to lower blood pressure (BP) in some essential hypertensives, as well as diabetic hypertensives. Soluble fiber in the form of guar is also quite effective in favorably influencing sugar-induced SBP elevations.

Animals↗

Synthesis of axially chiral benzamides utilizing tricarbonyl(arene)chromium complexes.

Axially chiral N,N-diethyl 2,6-disubstituted benzamides were stereo-selectively prepared utilizing planar chiral (arene)chromium complexes as an enantiomerically active form by following two methods. Ortho-lithiation of the enantiomerically pure planar chiral tricarbonyl(N,N-diethyl 2-methylbenzamide)chromium complex followed by electrophilic quenching gave axially chiral 2-methyl-6-substituted N,N-diethyl benzamide chromium complexes. Photo-oxidative demetalation produced the chromium-free axially chiral benzamides as optically active compounds. An alternative method for the preparation of axial chiral benzamides is an enantioselective lithiation at the benzylic methyl of meso tricarbonyl(N,N-diethyl 2,6-dimethylbenzamide)chromium with appropriate chiral lithium amide base followed by quenching with alkyl halides.

Journal Article↗

On the formation of aliphatic polycarbonates from epoxides with chromium(III) and aluminum(III) metal-salen complexes.

A DFT-based description is given of the CO2/epoxide copolymerization with a catalyst system consisting of metal (chromium, iron, titanium, aluminum)-salen complexes (salen = N,N'-bis(3,5-di-tert-butylsalicyliden-1,6-diaminophenyl) in combination with either chloride, acetate, or dimethylamino pyridine (DMAP) as external nucleophile. Calculations indicate that initiation proceeds through nucleophilic attack at a metal-coordinated epoxide, and the most likely propagation reaction is a bimolecular process in which a metal-bound nucleophile attacks a metal-bound epoxide. Carbon dioxide insertion occurs at a single metal center and is most likely the rate-determining step at low pressure. The prevalent chain terminating/degradation-the so-called backbiting, a reaction leading to formation of cyclic carbonate from the polymer chain-would involve attack of a carbonate nucleophile rather than an alkoxide at the last unit of the growing chain. The backbiting of a free carbonato chain end is particularly efficient. Anion dissociation from six-coordinate aluminum is appreciably easier than from chromium-salen complexes, indicating the reason why in the former case cyclic carbonate is the sole product. Experimental data were gathered for a series of chromium-, aluminum-, iron-, and zinc-salen complexes, which were used in combination with external nucleophiles like DMAP and mainly (tetraalkyl ammonium) chloride/acetate. Aluminum complexes transform PO (propylene oxide) and CO2 to give exclusively propylene carbonate. This is explained by rapid carbonate anion dissociation from a six-coordinate complex and cyclic formation. CO2 insertion or nucleophilic attack of an external nucleophile at a coordinated epoxide (at higher CO2 pressure) are the rate-determining steps. Catalysis with [Cr(salen)(acetate/chloride)] complexes leads to the formation of both cyclic carbonate and polypropylene carbonate with various quantities of ether linkages. The dependence of the activity and selectivity on the CO2 pressure, added nucleophile, reaction temperature, and catalyst concentration is complex. A mechanistic description for the chromium-salen catalysis is proposed comprising a multistep and multicenter reaction cycle. PO and CO2 were also treated with mixtures of aluminum- and chromium-salen complexes to yield unexpected ratios of polypropylene carbonate and cyclic propylene carbonate.

Journal Article↗

The effect of chromium on cholesterol-induced atherosclerosis in rabbits.

Rabbits fed on a 1% cholesterol diet for 30 days were injected daily with potassium chromate for a further 60 days. A 50% reduction in aortic intimal plaque area and in aortic total cholesterol content was observed. Control rabbits treated with chromium showed a significant increase in the chromium concentration of their aortas, liver and kidneys but not of the myocardium. Cholesterol-fed rabbits treated with chromium showed a significant increase in chromium concentrations in the liver and kidneys only. Serum cholesterol levels were consistently lower in the chromium-treated animals, although the differences did not reach significant levels.

Animals↗

Zinc has ambiguous effects on chromium (VI)-induced oxidative stress and apoptosis.

Zinc is an important cellular antioxidant. We investigated its role in chromium-induced oxidative stress and apoptosis in human tumor cell line Hep-2. The measured parameters included intracellular labile zinc content (Zinquin-E fluorescence), cell viability (WST-1 assay), oxidative stress (spectrophotometry), mitochondrial potential (flow cytometry), caspase-3 activity, and PARP cleavage (immunofluorescence). We found that Hep-2 cells contain abundant labile zinc stores that may be depleted by the ionophore TPEN or increased by external zinc supplementation. Chromium (VI)-induced cytotoxicity and apoptosis were enhanced in zinc-depleted cells after 24 h, in particular at chromium (VI) concentrations of 50 and 150 micromol/l. On the other hand, elevated levels of labile zinc were able to protect against apoptosis induced by 10 micromol/l chromium (VI) but at higher chromium (VI) concentrations (50 and 150 micromol/l) acted synergistically, significantly enhancing oxidative stress and the course of apoptosis, possibly through oxidative stress and mitochondrial damage.

Antioxidants↗

Rapid-extraction oxidation process to recover and reuse copper chromium and arsenic from industrial wood preservative sludge.

Chromated copper arsenate (CCA) wood preservative can form insoluble sludges when the hexavalent chromium component is reduced by wood extractives, wood particles and preservative additives in the solution. This sludge accumulates in treating solution work tanks, sumps and in-line filters and must be disposed of as hazardous wastes by waste disposal companies at high costs. A number of commercial sludges were investigated and found to contain 18-94% copper, chromium and arsenic as oxides combined with sand, oil, wood particles, additives and wood extractives. We have developed a multi-stage recycling process whereby approximately 97% of the CCA components are recovered from the sludge. It involves extraction with sodium hypochlorite to remove and oxidize chromium (more than 90%) and extract most of the arsenic (approx. 80%) followed by extraction of the copper and remaining arsenic and chromium with phosphoric acid. The phosphoric acid extract contains some trivalent chromium, which is subsequently oxidized by sodium hypochlorite. The combined oxidized extract containing CrVI, CuII and AsV was compatible with CCA treating solutions and could be re-used commercially for treating wood without having a significant effect on the preservative fixation rate or the leach resistance of the treated wood. A cost analysis showed that the economic savings from recovery of CCA chemicals and reduced landfill costs exceeded the variable costs for materials and energy for the process by as much as Can $966 per tonne of sludge if sodium sulfite can be acquired in bulk quantities for the process.

Arsenates↗

Chromium treatment of depression.

Eight patients with refractory mood disorders received chromium supplements and described dramatic improvements in their symptoms and functioning. In several instances, single-blind trials confirmed specificity of response to chromium. Side-effects were rare and mild, and most commonly included enhanced dreaming and mild psychomotor activation. To our knowledge, this is the first case series describing the response to chromium monotherapy. The putative antidepressant effects of chromium could be accounted for by enhancement of insulin utilization and related increases in tryptophan availability in the central nervous system, and/or by chromium's effects on norepinephrine release.

Journal Article↗

Effect of supplementation with chromium picolinate on antibody titers to 5-hydroxymethyl uracil.

Recent in vitro studies have shown that chromium (III) compounds such as chromium picolinate, a popular dietary supplement among people trying to lose weight, produce chromosome damage. We monitored levels of DNA damage in a chromium picolinate supplement trial by measuring antibodies titers to an oxidized DNA base, 5-hydroxymethyl-2'-deoxyuridine (HMdU), by enzyme-linked immunosorbent assays. Ten obese volunteer women completed a 8-week course of 400 micrograms chromium picolinate per day. In either absolute titers or percent of the baseline value, there were no changes in antibody titers at 4 or 8 weeks. The titers were very stable within individuals and those of one individual rarely crossed over others, which was reflected in an intraclass correlation coefficient of 0.99 (95% confidence interval: 0.96-1.00). There were no effects on glucose and lipid metabolism in this period. The results of this trial suggest that chromium (III) picolinate in a dose typically used for nutrient supplementation dose not increase oxidative DNA damage, as measured by anti-HMdU antibody levels.

Analysis of Variance↗

Effects of dietary chromium picolinate and ascorbic acid supplementation on egg production, egg quality and some serum metabolites of laying hens reared under a low ambient temperature (6 degrees C).

This experiment was conducted to evaluate the effects of chromium (chromium picolinate, Cr Pic) and vitamin C (L-ascorbic acid) supplementation on egg production and egg quality in laying hens (Hy-Line) kept at 18 degrees C (at thermo-neutral zone) or 6 degrees C (cold stress) in temperature-controlled rooms. One hundred and fifty laying hens (32 week-old) were divided into 5 groups, 30 hens per group. The laying hens kept at 6 degrees C temperature were fed either a basal diet (low temperature-basal diet, LTB group) or the basal diet supplemented with either 400 micrograms of Cr per kg diet (Cr group), 250 mg of L-ascorbic acid per kg diet (Vit C group) or 400 micrograms of Cr plus 250 mg of L-ascorbic acid per kg diet (Vit C + Cr group) while hens kept at 18 degrees C fed a basal diet (thermo-neutral-basal diet, TNB group). Performance and egg quality were significantly reduced in LTB group compared with TNB group. Supplemental chromium and vitamin C significantly increased live weight change, egg production, and improved feed efficiency in cold-stressed hens compared with group fed the basal diet at 6 degrees C brought up to the values of the group reared under thermoneutral conditions (18 degrees C). Egg production and egg weight were also greater in each supplemental group compared with the LTB group. Separately or as a combination, supplemental chromium and vitamin C increased serum insulin but decreased corticosterone, glucose and cholesterol concentrations. Results of the present study show that supplementing vitamin C and chromium, particularly as a combination, improved the performance of cold-stressed hens. Such a combination of supplement can offer a potential protective management practice in preventing cold stress-related losses in performance of laying hens.

Animals↗

Chromium supplementation can alleviate negative effects of heat stress on egg production, egg quality and some serum metabolites of laying Japanese quail.

This study was conducted to determine the effects of Cr (chromium picolinate, CrPic) supplementation at various levels (0, 200, 400, 800 or 1200 microg/kg of diet) on egg production, egg quality and serum concentrations of insulin, corticosterone and glucose in laying Japanese quail (Coturnix coturnix japanica) reared under conditions of heat stress (32.5 degrees C). Laying Japanese quail (n = 150; 45 d old) were divided into five groups of 30 birds. The quail were fed either a control diet containing 965 microg Cr/kg diet or the control diet supplemented with 200, 400, 800 or 1200 microg of Cr/kg diet. Increased supplemental chromium increased body weight (P = 0.05, linear), feed intake (P = 0.05, linear), egg production (P = 0.01, linear) and also improved feed efficiency (P = 0.01, linear). Increased supplemental chromium linearly increased egg weight (P = 0.01), eggshell thickness, egg specific gravity (P = 0.05) and Haugh unit (P = 0.01). Serum insulin concentration increased linearly (P = 0.01), whereas corticosterone and glucose concentration decreased linearly (P = 0.05) as dietary chromium increased. The best results were obtained with 1200 microg Cr/kg diet, and chromium supplementation at such a level can be considered to be protective management practice in a quail diet, reducing the negative effects of heat stress.

Animals↗

Chromium picolinate enhances skeletal muscle cellular insulin signaling in vivo in obese, insulin-resistant JCR:LA-cp rats.

Chromium is one of the few trace minerals for which a specific cellular mechanism of action has not been identified. Recent in vitro studies suggest that chromium supplementation may improve insulin sensitivity by enhancing insulin receptor signaling, but this has not been demonstrated in vivo. We investigated the effect of chromium supplementation on insulin receptor signaling in an insulin-resistant rat model, the JCR:LA-corpulent rat. Male JCR:LA-cp rats (4 mo of age) were randomly assigned to receive chromium picolinate (CrPic) (obese n=6, lean n=5) or vehicle (obese n=5, lean n=5) for 3 mo. The CrPic was provided in the water, and based on calculated water intake, rats randomized to CrPic received 80 microg/(kg.d). At the end of the study, skeletal muscle (vastus lateralis) biopsies were obtained at baseline and at 5, 15, and 30 min postinsulin stimulation to assess insulin signaling. Obese rats treated with CrPic had significantly improved glucose disposal rates and demonstrated a significant increase in insulin-stimulated phosphorylation of insulin receptor substrate (IRS)-1 and phosphatidylinositol (PI)-3 kinase activity in skeletal muscle compared with obese controls. The increase in cellular signaling was not associated with increased protein levels of the IRS proteins, PI-3 kinase or Akt. However, protein tyrosine phosphatase 1B (PTP1B) levels were significantly lower in obese rats administered CrPic than obese controls. When corrected for protein content, PTP1B activity was also significantly lower in obese rats administered CrPic than obese controls. Our data suggest that chromium supplementation of obese, insulin-resistant rats may improve insulin action by enhancing intracellular signaling.

Animals↗

Induction of DNA strand breaks in peripheral lymphocytes by soluble chromium compounds.

1. Incubation of human lymphocytes with sodium dichromate (CrVI) at 37 degrees C for 3 h resulted in a dose-dependent increase in DNA strand breaks without concurrent cytotoxicity. In contrast, chromium acetate hydroxide (CrIII) failed to induce DNA strand breaks at sub-cytotoxic concentrations. 2. DNA strand breaks were also detected in the peripheral lymphocytes of Wistar rats, 24 h after intratracheal instillation of sodium dichromate (1.3 and 2.5 mg kg-1). Instillation of chromium acetate hydroxide (up to 21.8 mg kg-1) failed to induce DNA strand breaks in peripheral lymphocytes. In accord with previous studies, hexavalent chromium was found to be more readily absorbed from the lungs into the peripheral blood than chromium in its trivalent form. 3. The results of this study indicate that fluorometric analysis of DNA unwinding (FADU) in peripheral lymphocytes might be a convenient method of measuring an important biological effect of chromium in occupationally-exposed workers.

Animals↗

Compliance of a cobalt chromium coronary stent alloy--the COVIS trial.

BACKGROUND: Cobalt chromium coronary stents are increasingly being used in percutaneous coronary interventions. There are, however, no reliable data about the characteristics of unfolding and visibility of this stent alloy in vivo. The aim of this study is to compare cobalt chromium coronary stents with conventional stainless steel stents using intracoronary ultrasound. METHODS: Twenty de novo native coronary stenoses < or = 20 mm in length (target vessel reference diameter > or = 2.5 and < or = 4.0 mm) received under sequential intracoronary ultrasound either a cobalt chromium stent (Multi-Link Vision; n = 10) or a stainless steel stent (Multi-Link Zeta; n = 10). RESULTS: For optimal unfolding, the cobalt chromium stent requires a higher balloon deployment pressure (13.90 +/- 2.03 atm) than the stainless steel stent (11.50 +/- 2.12 atm). Furthermore, the achieved target vessel diameter of the cobalt chromium stent (Visibility-Index QCA/IVUS Multi-Link Vision 1.13 / Multi-Link Zeta 1.04) is more easily overrated by Quantitative Coronary Analysis. CONCLUSION: These data indicate that stent material-specific recommendations for optimal implantation pressure and different stent material with an equal design should both be considered in interpreting QCA-analysis.

Journal Article↗

Hexavalent chromium recovery by liquid-liquid extraction with tributylphosphate from acidic chloride media.

A method is introduced for recuperation of chromium(VI) in water samples by liquid-liquid extraction with tributylphosphate PO(C4H9O)3 (TBP) from acidic chloride media. The optimum conditions for quantitative extraction of Cr(VI) were evaluated by varying the experimental parameters, such as the shaking period, the pH of the aqueous phase, the hydrochloric acid concentration, the hydrogen and chloride ion concentrations, the extractant concentration and the ratio of aqueous-to-organic phase. The probable extracted species of hexavalent chromium in organic phase, deduced from log-log plots, were H2CrO4 in acid media in absence of chloride and HCrO3Cl in acidic chloride media. Chromium(VI) was found to be extracted with tributylphosphate from acidic chloride media according to the following reaction: HCrO4-(aq), + 2H+(aq) + Cl-(aq) + 2TBP(org) <==> [HCrO3Cl, 2TBP](org) + H2O(aq). Since the tributylphosphate (TBP) exhibited a high selectivity for chromium(VI), this method can be applicable to the extraction and the determination of chromium in both oxidation states [Cr(VI) and Cr(III)] in water samples.

Journal Article↗

[Repercussions of chromium picolinate in the protein metabolism based on the age].

ANTECEDENTS: Commercialized like dietetic supplement, chromium picolinate has been promoted to favour the increase of muscle mass and the loss of weight, due to its' effect on the action of insulin. OBJECTIVE: To evaluate the effect of supplementation of the diet with chromium (500 microg/kg) in the form of chromium picolinate (CrPic) (12 days) on growth and protein turnover in rats at different growth stages (infantile and puberal). RESULTS AND DISCUSSION: No significant effect of CrPic on bodyweight gain, feed intake and feed conversion rate was observed at any of the stages of development studied. CrPic seems to increase the muscle mass, either by stimulating protein anabolism due to the involution of the insulin by chromium, or by reducing protein catabolism. CONCLUSIONS: Since the use of chromium picolinate could jeopardize the correct renal function and its' beneficial effects are not evident, it should always be consumed with caution.

Age Factors↗