Reference

Lack of micronuclei formation in bone marrow of rats after repeated oral exposure to nickel sulfate hexahydrate

All Rights Reserved. Lack of micronuclei formation in bone marrow of rats after repeated oral exposure to nickel sulfate hexahydrate. Oller, Adriana R.; Erexson, Greg (NiPERA, Durham, NC 27713, USA). Mutation Research, Genetic Toxicology and Environmental Mutagenesis, 626(1-2), 102-110 (English) 2007 Elsevier B.V. CODEN: MRGMFI. ISSN: 1383-5718. DOCUMENT TYPE: Journal CA Section: 4 (Toxicology) Workplace exposures to mixts. of nickel compds. have been assocd. with excess respiratory cancer risk. Animal studies with individual nickel compds.There are some reagents like 10101-97-0 is used in this study. indicate that not all nickel substances have the same potency or potential to induce tumors. The bioavailability of nickel ions at crit. cellular sites seems to be important to det. the potential of a substance to induce tumors in animals, but much less is understood about the exact nature (genotoxic or non-genotoxic) of the nickel effects. Within many regulatory frameworks (e.g., European Union), substances are classified for mutagenicity based on the available data and this classification will often influence the mode of action assigned to carcinogenic substances and the way in which risk assessment will be conducted. The objective of this study was to evaluate the ability of nickel sulfate hexahydrate to induce micronuclei in polychromatic erythrocytes (PCEs) in rat bone marrow. This study was conducted according to OECD and EU protocol guidelines. In the dose range-finding assays, the max. tolerated dose was estd. to be 500 mg/kg/day. The doses used in the micronucleus assay were 125, 250, and 500 mg/kg/day. At least 2000 PCEs per animal were analyzed for micronuclei in PCEs. Cytotoxicity was assessed by scoring a min. of 500 consecutive total polychromatic (PCE) and normochromatic (NCE) erythrocytes (PCE/NCE ratio). Nickel sulfate hexahydrate did not induce significant increases in micronucleated PCEs at any dose examd. The neg. results in the present study contribute significantly to the wt. of evidence evaluation of the mutagenicity (chromosomal level) of nickel substances. These results are consistent with a non-genotoxic mode of action for sol. nickel that could explain the enhancement of cancer risk seen among refinery workers with mixed exposures and its lack of carcinogenicity in animal studies with single exposures. .

Observation of growth steps with full and half unit cell heights of the {001} faces of nickel sulfate hexahydrate in relation to the defect structure

Observation of growth steps with full and half unit cell heights of the {001} faces of nickel sulfate hexahydrate in relation to the defect structure. Van Enckevort, W. J. P.; Klapper, H. (Fac. Sci., Catholic Univ., Nijmegen 6525 ED, Neth.). J. Cryst. Growth, 80(1), 91-103 (English) 1987. CODEN: JCRGAE. ISSN: 0022-0248. DOCUMENT TYPE: Journal CA Section: 75 (Crystallography and Liquid Crystals) On the as-grown {001} faces of aq. soln.-grown NiSO4.Several substances like 10101-97-0 may be metioned in this study.6H2O crystals, surface patterns composed of very low (1.8 and 0.9 nm) steps were studied by optical phase contrast microscopy. Most dominant were the growth centers emitting interlaced step trains in a 2- or 4-fold symmetry. By x-ray diffraction topog. some of the step sources could be correlated with the outcrops of pure screw dislocations, b = [001], l = [001]. In many cases the equidistant step trains on the surfaces were perturbed by extra half-steps generated by screw dislocation outcrops. This leads to bunch formation. Trails introduced by post-growth screw dislocation glide were commonly encountered in the step patterns. X-ray topog. confirmed the occurrence of screw dislocation glide in the {001} growth sectors. A 2nd type of dislocation ending at the {001} faces (pure edge type, line direction {001}, also found by x-ray topog. did not influence the surface patterns. .