Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
ESTIMATES OF THE CHROMIUM(VI) REDUCING CAPACITY IN HUMAN-BODY COMPARTMENTS AS A MECHANISM FOR ATTENUATING ITS POTENTIAL TOXICITY AND CARCINOGENICITY
Autore:
DEFLORA S; CAMOIRANO A; BAGNASCO M; BENNICELLI C; CORBETT GE; KERGER BD;
Indirizzi:
UNIV GENOA,INST HYG & PREVENT MED,VIA PASTORE 1 I-16132 GENOA ITALY MCLAREN HART INC,CHEMRISK DIV IRVINE CA 92714
Titolo Testata:
Carcinogenesis
fascicolo: 3, volume: 18, anno: 1997,
pagine: 531 - 537
SICI:
0143-3334(1997)18:3<531:EOTCRC>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
HEXAVALENT CHROMIUM; ASCORBIC-ACID; METABOLIC DEACTIVATION; ALVEOLAR MACROPHAGES; GLUTATHIONE; REDUCTION; MUTAGENICITY; ERYTHROCYTES; CHROMATE; LUNG;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
60
Recensione:
Indirizzi per estratti:
Citazione:
S. Deflora et al., "ESTIMATES OF THE CHROMIUM(VI) REDUCING CAPACITY IN HUMAN-BODY COMPARTMENTS AS A MECHANISM FOR ATTENUATING ITS POTENTIAL TOXICITY AND CARCINOGENICITY", Carcinogenesis, 18(3), 1997, pp. 531-537

Abstract

Estimates of the overall reducing capacity of hexavalent chromium(VI)in some human body compartments were made by relating the specific reducing activity of body fluids, cell populations or organs to their average volume, number, or weight, Although these data do not have absolute precision or universal applicability, they provide a rationale forpredicting and interpreting the health effects of chromium(VI), The available evidence strongly indicates that chromium(VI) reduction in body fluids and long-lived non-target cells is expected to greatly attenuate its potential toxicity and genotoxicity, to imprint a threshold character to the carcinogenesis process, and to restrict the possible targets of its activity, For example, the chromium(VI) sequestering capacity of whole blood (187-234 mg per individual) and the reducing capacity of red blood cells (at least 93-128 mg) explain why this metal isnot a systemic toxicant, except at very high doses, and also explain its lack of carcinogenicity at a distance from the portal of entry into the organism, Reduction by fluids in the digestive tract, e,g, by saliva (0,7-2.1, mg/day) and gastric juice (at least 84-88 mg/day), and sequestration by intestinal bacteria (11-24 mg eliminated daily with feces) account for the poor intestinal absorption of chromium(VI), The chromium(VI) escaping reduction in the digestive tract will be detoxified in the blood of the portal vein system and then in the liver, having an overall reducing capacity of 3300 mg, These processes give reasons for the poor oral toxicity of chromium(VI) and its lack of carcinogenicity when introduced by the oral route or swallowed following reflux from the respiratory tract. In terminal airways chromium(VI) is reduced in the epithelial lining fluid (0.9-1.8 mg) and in pulmonary alveolar macrophages (136 mg), The peripheral lung parenchyma has an overall reducing capacity of 260 mg chromium(VI), with a slightly higher specific activity as compared to the bronchial tree. Therefore, even in the respiratory tract, which is the only consistent target of chromium(VI) carcinogenicity in humans (lung and sinonasal cavities), there arebarriers hampering its carcinogenicity, These hurdles could be only overwhelmed under conditions of massive exposure by inhalation, as it occurred in certain work environments prior to the implementation of suitable industrial hygiene measures.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 21/09/20 alle ore 01:48:39