Routine patch testing V. Correlations of reactions to the site of dermatitis and the history of the patient.
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Age Factors↗
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Results for “Chromium Compounds”
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[Bronchopulmonary precancerous conditions and tumors--risk groups from the occupational medicine viewpoint].
Risk groups with regard to bronchopulmonary precancerous and tumor diseases of occupational origin can be deduced from current occupational disease statistics. Most prominent are those working with asbestos. Each year about 250 asbestos-associated bronchial carcinomas and 400 mesotheliomas are recognized and compensated; the tendency is increasing. Because of the long latency time, the frequency peak will probably be reached in about 15 years in spite of the prohibition of asbestos usage. The second place is probably taken by malignomas among the underground uranium mine workers in Thuringia and Saxony (SDAG Wismut). Next come bronchial carcinomas with silicosis (carcinoma in scar tissue) after exposure to chromium(VI) and arsenic compounds as well as various other chemicals and metals. Dose-activity relationships are significant for all occupational carcinogenic agents, as there are also often syncancerogenic influences (especially smoking). From the data on previous loading, high risk groups, for example, among the insulation workers exposed to asbestos or uranium miners in the so-called "wild years", can be defined. A suitable screening method for the detection of bronchopulmonary tumors in the early stages has not yet been established. Medical checkups for the respective risk groups concentrate on the early X-ray detection of circular foci. As shown by recent studies, cytological sputum diagnosis, (fluorescence) bronchoscopy, and BAL cytology must be employed much more frequently in the high risk groups so that the prognostically more favorable stages of preneoplasm and carcinoma in situ can be detected and possibly treated curatively. These procedures are currently reaching a considerably higher sensitivity with the help of modern molecular biology techniques (e.g. detection of tumor-associated genetic changes and gene products). This contributes to an improvement in surveillance examinations with increasing detection of the curable early forms of tumors. However, only the further development of primary prevention, i.e. the greatest possible minimization or, if possible, total elimination of contact with carcinogenic agents and the consequent control of occupational protection will lead to a drastic reduction in the occupational risk of cancer.
Carcinoma, Bronchogenic↗
Prevention of lung cancer through the use of knowledge on asbestos and other work-related causes--Norwegian experiences.
This review attempts to estimate the contribution of different known work-related causes of lung cancer in the Norwegian male population in order to predict the potential of prevention of work-related cases. The presented estimates are based on data from epidemiologic studies made in Norway, but may be of significance for other countries with a similar work-force structure. Over the past decade asbestos-related lung cancer appears to have contributed about two-thirds of the lung cancers that have been related to work exposure in Norway, for example, possibly 125-175 of the 1100 cases that occurred among Norwegian men in 1987. The potential for prevention is, however, greater due to synergism. To a less extent compounds of nickel and chromium have also contributed, along with exposure to polycyclic aromatic hydrocarbons, radon daughters, seafaring work, and other, less significant specific and nonspecific determinants of lung cancer.
Asbestosis↗
Effect of powder/liquid ratio on physical and chemical properties of C&B Metabond.
The purpose of this study was to examine the effect of varying the powder/liquid ratio on the physical properties and the degree and rate of curing of C&B Metabond cement. The powder/liquid ratios evaluated had no effect on the tensile bond strength of Rexillium III to etched enamel or on the retention of cemented full cast crowns. The higher P/L ratio resulted in an increased vertical displacement of the cemented crowns. The rate of monomer conversion and the total conversion were not affected significantly by the different P/L ratios.
Analysis of Variance↗
Effects of dengue virus infection on peripheral blood cells of mice exposed to hexavalent chromium with drinking water.
BACKGROUND & OBJECTIVE: The occupational and non-occupational exposure to hexavalent chromium Cr (VI) is common. The effect of chromium compromises the immune response of the host. Dengue virus (DV) infection causes various changes in the peripheral blood cells. It is, therefore, possible that the chromium toxicity may affect the disease process during DV infection. The present study aims to study the effects of dengue virus infection on peripheral blood cells of mice fed Cr (VI) with drinking water. METHODS: One group of mice was given ad libitum drinking water containing Cr (VI) and the other group used as the normal control mice was given plain water to drink. At the 3, 6 and 9 wk of Cr (VI) drinking, a set of mice from each group was inoculated intracerebrally (ic) with DV and studied at the 4th and 8th day post inoculation. RESULTS: It was observed that Cr (VI) drinking led to reduction in lymphocytes, haemoglobin and the haematocrit values while the granulocyte, monocyte and platelet counts were increased. On the other hand, most of the parameters were decreased following inoculation of normal mice with DV. In Cr (VI)-fed mice the effects of DV infection were minimal. The most significant finding of these experiments was that the reduction in platelet counts following inoculation with DV was markedly less in Cr (VI)-fed mice than that in DV-inoculated normal control mice. INTERPRETATION & CONCLUSION: Cr(VI) compounds have been declared as a potent occupational carcinogen. On the contrary, Cr(III) salts such as chromium polynicotinate, chromium chloride and chromium picolinate, are used as micronutrients and nutritional supplements, and have been shown to exhibit health benefits in animals and humans. Whether therapeutic doses of chromium (III) compounds may be able to prevent the DV-induced fall in platelet counts, needs to be investigated.
Administration, Oral↗
Kinetics of catalytic oxidation of benzene, n-hexane, and emission gas from a refinery oil/water separator over a chromium oxide catalyst.
With the advances made in the past decade, catalytic incineration of volatile organic compounds (VOCs) has become the technology of choice in a wide range of pollution abatement strategies. In this study, a test was undertaken for the catalytic incineration, over a chromium oxide (Cr2O3) catalyst, of n-hexane, benzene, and an emission air/vapor mixture collected from an oil/water separator of a refinery. Reactions were carried out by controlling the feed stream to constant VOC concentrations and temperatures, in the ranges of 1300-14,700 mg/m3 and 240-400 degrees C, respectively. The destruction efficiency for each of the three VOCs as a function of influent gas temperature and empty bed gas residence time was obtained. Results indicate that n-hexane and the oil vapor with a composition of straight- and branch-chain aliphatic hydrocarbons exhibited similar catalytic incineration effects, while benzene required a higher incineration temperature or longer gas retention time to achieve comparable results. In the range of the VOC concentrations studied, at a given gas residence time, increasing the operating temperature of the catalyst bed increased the destruction efficiency. However, the much higher temperatures required for a destruction efficiency of over 99% may be not cost-effective and are not suggested. A first-order kinetics with respect to VOC concentration and an Arrhenius temperature dependence of the kinetic constant appeared to be an adequate representation for the catalytic oxidation of these volatile organics. Activation energy and kinetic constants were estimated for each of the VOCs. Low-temperature destruction of the target volatile organics could be achieved by using the Cr2O3 catalyst.
Air Pollutants, Occupational↗
Influence of the drying conditions of Sargassum sp. alga on the bioadsorption of hexavalent chromium.
Industrial wastes containing synthetic organic compounds and heavy metals are among the most dangerous residues, whose growth has followed the increase in industrial activity. Heavy metals are readily assimilated into the food chain and therefore easily accumulated in the ecosystem. To remove heavy metals from aqueous solutions, marine algae may be used as adsorbents either in their natural form or after treatments by a cross-linking process to improve their mechanical resistance. Drying of biosorbents, such as marine algae, is mentioned in many previous works as a step preceding the adsorption/dessorption cycle. Concerning algae, drying of its fresh biomass allows for proper storage and enhances performance in the sorption of heavy metals. In this work, physical and morphological analyses of fresh and dried Sargassum sp. marine algae, harvested offshore São Sebastião, São Paulo state, Brazil, were performed in order to assess the influence of drying conditions on the biosorption process. Chromium concentrations were also determined in different parts of the algal structure before and after the biosorption process. The drying promoted structural changes in the algae, like shrinkage and porosity reduction. It was also observed that the chromium retention was dependent on the structural arrangement of the alga parts, in which the leaf was the major biosorbent.
Adsorption↗
Photodynamic aspects of some metal complexes.
The potential phototoxic capacity of some metal compounds of clinical significance in dermatology has been investigated by means of the photohemolysis technique. No photosensitized hemolysis of erythrocytes was observed with the chromium, nickel, copper and cobalt compounds studied. On the contrary, nickel and cobalt compounds proved to be efficient in quenching singlet oxygen mediated photo-oxidative membrane damage of red blood cells. Cadmium compounds showed a pronounced photohemolytic activity and the reaction was oxygen dependent. The deuterium test for singlet oxygen showed a significant increase in photohemolytic efficiency. The addition of histidine, a known quencher of singlet oxygen, resulted in a significant inhibition of the photohemolysis. Pronounced photo-oxidative damage to plasma membranes was also observed in vitro cultivated cells by means of scanning electron microscopy.
Chromium↗
Effects of chromium on the immune system.
Chromium is a naturally occurring heavy metal found commonly in the environment in trivalent, Cr(III), and hexavalent, Cr(VI), forms. Cr(VI) compounds have been declared as a potent occupational carcinogen among workers in chrome plating, stainless steel, and pigment industries. The reduction of Cr(VI) to Cr(III) results in the formation of reactive intermediates that together with oxidative stress oxidative tissue damage and a cascade of cellular events including modulation of apoptosis regulatory gene p53, contribute to the cytotoxicity, genotoxicity and carcinogenicity of Cr(VI)-containing compounds. On the other hand, chromium is an essential nutrient required to promote the action of insulin in body tissues so that the body can use sugars, proteins and fats. Chromium is of significant importance in altering the immune response by immunostimulatory or immunosuppressive processes as shown by its effects on T and B lymphocytes, macrophages, cytokine production and the immune response that may induce hypersensitivity reactions. This review gives an overview of the effects of chromium on the immune system of the body.
Animals↗
Effect of supplemental dietary chromium or nicotinic acid on carbohydrate metabolism during basal, starvation, and refeeding periods in poults.
A series of experiments were conducted with turkey poults to ascertain the effects of supplemental chromium or excess of nicotinic acid on growth and carbohydrate metabolism. A 23% protein starter diet was selected to emphasize the effect of chromium under basal, starvation for 48 hr, and refeeding periods. Thirty percent protein diets were also used to determine if the effects were compounded by protein levels. Supplemental chromium (20 ppm) significantly increased (P less than .05) weight at 3 weeks of age of poults consuming 23% protein diets, while an additional 250 ppm of nicotinic acid had little effect on poult weight at 3 weeks (P greater than .05). Supplemental chromium did not increase (P greater than .05) feed consumption of poults consuming both 23 and 30% protein diets. Supplemental chromium increased liver glycogen at 3 weeks of age and following refeeding after the 48 hr fast (P less than .05). Blood glucose was significantly affected by starvation-refeeding (P less than .05) but was not affected by either chromium or nicotinic acid. Supplemental chromium increased (P less than .01) active glycogen synthetase, while nicotinic acid increased (P less than .01) active phosphorylase at both protein levels. Synthetase was not decreased by starvation but was increased (P less than .01) by refeeding regardless of protein level fed. Phosphorylase was not affected by a starvation-refeeding regimen. Chromium supplementation increased in the vitro incorporation of (14C) glucose into glycogen during basal, starvation and refeeding periods (P less than .01), again, regardless of protein level.
Animal Feed↗
Current concepts in the assessment of effects of metals in chronic low-level exposures--considerations of experimental and epidemiological evidence.
Human exposure to metals and their compounds may give rise to a number of adverse effects. Of particular interest are such effects that can be elicitated by chronic low-level exposure, since such exposures may occur in human populations both in the general environment and occupationally. The adverse effect that occurs at the lowest exposure has been termed the "critical effect" since it is critical in relation to preventive action aiming at limiting exposures to a safe level. When reviewing the present evidence on the toxicology of metals it becomes evident that "critical effects" may be related to various organ systems, disease categories and biochemical mechanisms of damage. A category of effects, which is of particular interest in relation to critical effects, is hypersensitivity (e.g. with dermal or respiratory manifestations). However conceptual recognition of this category of effects is as yet incomplete. Other important considerations are whether effects display threshold- or non-threshold type dose-response relationships, the latter category obviously being more likely to display a low incidence response at low dose exposure. In this context mutagenic, carcinogenic, developmental and reproductive toxicity of metals are of particular interest. Information on these types of effects compiled during previous meetings of the scientific committee on the toxicilogy of metals and recently updated, indicates that some compounds of arsenic, beryllium, cadmium, chromium and nickel may be regarded as carcinogenic for humans. Available evidence in experimental systems as well as in humans concerning effects of metallic compounds on male and female reproductive systems, congenital teratogenicity and perinatal toxicity as well as effects on the developing central nervous system indicates that such effects should be considered further in relation to critical effects for arsenic, cadmium, lead, mercury and their compounds.
Animals↗
BLOOD LOSS IN PURE ANCYLOSTOMA DUODENALE INFECTION IN EGYPTIAN FARMERS.
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Adolescent↗
Cis-dinitrito(1,4,8,11-tetraazacyclotetradecane-kappa4N)chromium(III) nitrite.
In the title compound, [Cr(ONO)(2)(cyclam)]NO(2) (cyclam is 1,4,8,11-tetraazacyclotetradecane, C(10)H(24)N(2)), the complex cation is located on a twofold symmetry axis. The central Cr atom has a distorted octahedral coordination, involving two Cr-O bonds, with the monodentate nitrite O atoms adopting a cis configuration, and four Cr-N bonds. The mean Cr-N and Cr-O distances are 2.0895 (14) and 1.9698 (14) A.
Journal Article↗
Tetra-mu-chloro-1:2kappa4Cl;1:3kappa4Cl-dimethyl-2kappaC,3kappaC-tetrakis(tetrahydrofuran)-1kappa2O,2kappaO,3kappaO-chromium(II)dizinc(II).
The title compound, [CrZn2(CH3)2Cl4(C4H8O)4], contains a central distorted octahedral Cr atom, located at an inversion center, bound to two tetrahydrofuran ligands and four chloro ligands that bridge to two symmetry-related tetrahedral Zn atoms. The coordination around zinc is completed by methyl and tetrahydrofuran ligands. This structure is compared with a previously reported complex of vanadium, and their differences in metric parameters are explained.
Journal Article↗
Asymmetric dearomatization of the furan ring promoted by conjugate organolithium addition to (menthyloxy)(3-furyl)carbene complexes of chromium.
The sequential low-temperature addition reaction of an organolithium compound and methyl triflate to (menthyloxy)(3-furyl)carbene complexes of chromium and tungsten proceeded with excellent regioselectivity (1,4-addition) and diastereoselectivity (2,3-trans disposition of the nucleophile and electrophile groups) to afford new 2,3-disubstituted (2,3-dihydro-3-furyl)carbene complexes. In addition, a high degree of diastereofacial selectivity was achieved by employing alkenyllithium compounds. After detachment of both the metal fragment and the chiral auxiliary group, trisubstituted 2,3-dihydrofuran derivatives containing a quaternary stereogenic center at the C3 position were obtained. The characterization, including X-ray crystallography, of a novel type of stable four-membered chelate (eta(2)-alkene)tetracarbonylcarbene complex of chromium is also reported.
Journal Article↗
Effect of potassium dichromate and fenitrothion on hemoglobins of Chironomus riparius Mg. (Diptera, Chironomidae) larvae: potential biomarker of environmental monitoring.
In an attempt to identify Chironomus hemoglobins as biomarkers for environmental monitoring, alterations in the hemoglobins in Chironomus riparius Mg. (Diptera: Chironomidae) larvae, exposed to potassium dichromate and fenitrothion, were investigated under laboratory conditions. The hemoglobins were evaluated in terms of their total contents by a cyanomethemoglobin procedure, individual components by electrophoresis of isoelectric focusing, and their oxidation by multi wavelength rapid-scanning spectrophotometry. The total hemoglobin contents increased at the high level of fenitrothion exposure. No variations in the individual hemoglobin component levels were found, by exposure to either fenitrothion or potassium dichromate. Whereas, the absorption spectra of the hemoglobins showed decreases in the peaks corresponding to the oxyhemoglobins by exposure to both compounds, but more sensitively by the chromium, which probably reflects the increase of the autoxidation of the oxyhemoglobins to methemoglobins by these compounds. These results suggest that autoxidation of the hemoglobins in Chironomus riparius seems to be a sensitive parameter in response to redox-active chemical exposure, and this biochemical parameter could be developed as a biomarker in environmental monitoring.
Animals↗
Some metals and metallic compounds.
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Animals↗
Occupational exposure to chromium--an assessment of environmental pollution levels and biological monitoring of exposed workers.
In an aircraft construction factory where adhesives containing Cr(VI) compounds were used, the risk of chromium exposure was studied by assessing airborne chromium levels and urinary levels of chromium excretion. Chromium exposure was evaluated by personal sampling over a period of 4 hr in a group of 16 occupational workers selected from a group of 55. Chromium absorption was determined by collecting urine samples from all subjects (n = 55) at 3 different times: prior to the work-shift at the beginning of the working week and prior to and after the workshift at the end of the working week. Each urine sample was tested for chromium and creatinine concentration. Results showed very low exposure to airborne chromium, since values obtained (0.02-1.5 micrograms/m3, GM: 0.17, GSD: 5.34 micrograms/m3) were significantly lower than the ACGIH Hygiene Standard (50 micrograms/m3). Likewise, urinary chromium excretion (0.16-7.74 micrograms/g creat.) was higher than excretion in the general population (0.07-0.17 microgram/g creat.) but lower than BEI-ACGIH (30 micrograms/g creat.). The greatest difference between excretion levels measured before and after the workshift was 2.44 micrograms/g creat, i.e. 4 times lower than the difference proposed by ACGIH (10 micrograms/g creat.).
Adult↗