PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “ARSENIC AND COMPOUNDS”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMed2005

A comparative study of the sub-chronic toxic effects of three organic arsenical compounds on the urothelium in F344 rats; gender-based differences in response.

Epidemiological studies indicated that human arsenic exposure can induce urinary bladder cancer. Methylation of inorganic arsenic can generate more reactive and toxic organic arsenical species. In this regard, it was recently reported that the methylated arsenical metabolite, dimethylarsinic acid [DMA(V)], induced urinary bladder tumors in rats. However, other methylated metabolites, like monomethylarsonic acid [MMA(V)] and trimethylarsine oxide (TMAO) were not carcinogenic to the urinary bladder. In order to compare the early effects of DMA(V), MMA(V), and TMAO on the urinary bladder transitional cell epithelium at the scanning electron microscope (SEM) level, we investigated the sub-chronic (13 weeks) toxicological effects of MMA(V) (187 ppm), DMA(V) (184 ppm), TMAO (182 ppm) given in the drinking water to male and female F344 rats with a focus on the urinary bladder in this study. Obvious pathological changes, including ropy microridges, pitting, increased separation of epithelial cells, exfoliation, and necrosis, were found in the urinary bladders of both sexes, but particularly in females receiving carcinogenic doses of DMA(V). Urine arsenical metabolic differences were found between males and females, with levels of MMA(III), a potential genotoxic form, higher in females treated with DMA(V) than in males. Thus, this study provides clear evidence that DMA(V) is more toxic to the female urinary bladder, in accord with sensitivity to carcinogenesis. Important gender-related metabolic differences including enhanced presentation of MMA(III) to the urothelial cells might possibly account for heightened sensitivity in females. However, the potential carcinogenic effects of MMA(III) need to be further elucidated.

Animals↗
PubMed2002

Transformation by inorganic arsenic compounds of normal Syrian hamster embryo cells into a neoplastic state in which they become anchorage-independent and cause tumors in newborn hamsters.

Arsenic is a known human carcinogen, but little evidence exists for its carcinogenicity in animals. In order to investigate the ability of inorganic arsenics to transform normal cells into a neoplastic state, mass cultures of normal, diploid Syrian hamster embryo (SHE) cells exposed to various concentrations of sodium arsenite or sodium arsenate for 48 hr were continually passaged and tested for neoplastic transformation, as determined by anchorage-independent growth in semisolid agar and tumorigenicity in newborn hamsters. Twenty-one of 22 (96%) untreated, control cultures senesced by 20 passages. While 1 culture escaped senescence, it did not acquire the ability to either grow in semisolid agar or form tumors in animals. Ten of 14 (71%) cultures exposed to sodium arsenite or sodium arsenate escaped senescence. Nine of the 10 (90%) arsenic-treated immortal cultures acquired the anchorage-independent phenotype. Five of 5 anchorage-independent cultures examined were tumorigenic. Two of 3 morphologically transformed colonies induced by sodium arsenate also acquired the ability to grow in semisolid agar when isolated. Amplification of the c-myc or c-Ha-ras oncogene was detected in 3 of 5 and 4 of 5 tumorigenic cell lines, respectively. Both c-myc and c-Ha-ras were amplified even in a preneoplastic, anchorage-dependent cell line, but neither was amplified in 6 of 9 anchorage-independent cell lines. Overexpression of c-myc and c-Ha-ras mRNA was observed in most of the neoplastically transformed cell lines but not in the preneoplastic cell line. Experiments using the methylation-sensitive restriction endonuclease isoschizomers HpaII and MspI revealed hypomethylation of c-myc and c-Ha-ras in the 5'-CCGG sequence of arsenic-exposed cell lines but not in the parental SHE cells or a spontaneously transformed cell line. Thus, inorganic arsenics induce neoplastic transformation of normal, diploid mammalian cells. Overexpression of oncogenes by DNA hypomethylation may participate in the arsenic-induced neoplastic transformation of mammalian cells.

Animals↗