Linked Life Data

8812232

Source:http://linkedlifedata.com/resource/pubmed/id/8812232

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1997-1-27
pubmed:abstractText
Toxicity studies were performed by exposing F344/N rats and B6C3F1 mice to 2- and 4-chloronitrobenzene (CNB) by whole-body inhalation 6 hr/day, 5 days/week, for 13 weeks. Animals were evaluated for clinical chemistry (rats), hematology (rats), histopathology, and body/organ weights. Exposure concentrations were 0, 1.1, 2.3, 4.5, 9, and 18 ppm for 2-CNB and 0, 1.5, 3, 6, 12, and 24 ppm for 4-CNB. All rats in the 2-CNB study survived until the end of the study. Two male mice in the 18-ppm group in the 2-CNB study, however, died during Week 12; no deaths attributable to 4-CNB exposure occurred in rats or mice. In both studies, the mean body weight gains of exposed animals were similar to those of the respective controls. In rats, inhalation exposure to 2- or 4-CNB resulted in methemoglobinemia leading to a regenerative anemia and a variety of tissue changes secondary to the oxidative erythrocyte injury. In the 2-CNB study, methemoglobinemia resulted in a normocytic, normochromic, responsive anemia, whereas with 4-CNB, the methemoglobinemia was more severe and resulted in a macrocytic, hyperchromic, responsive anemia. Alterations of erythrocyte morphology were observed in both studies; changes included Heinz bodies, poikilocytes, and polychromasia. In rats, both isomers caused increases in serum activities of alanine aminotransferase and sorbitol dehydrogenase and increased bile acid concentrations. Microscopic liver changes included hemosiderin deposition in Kupffer cells (rats and mice exposed to 4-CNB), hepatocytomegaly (mice), and cytoplasmic basophilia (rats). Hepatocellular necrosis and chronic inflammation observed in mice were rather specific to the 2-CNB isomer, as only slight evidence of focal necrosis in the liver was observed in mice exposed to 4-CNB. Splenic lesions included hemosiderin accumulation capsular fibrosis, and increased hematopoietic cell proliferation. Increased bone marrow hemosiderin and hematopoietic cell proliferation and kidney tubule hemosiderin deposition were also observed. Other findings, attributed to chemical exposure but not to the hematotoxicity, were described. Lesions included hyaline droplet nephropathy and degeneration of the testis in male rats exposed to 4-CNB, inflammation of the harderian gland in rats exposed to 4-CNB, hyperplasia of the nasal cavity epithelium in rats exposed to 2-CNB, and hyperplasia of the forestomach epithelium in mice exposed to 4-CNB; these lesions have not been described previously in studies with these chemicals. Based on the exposure concentrations evaluated, A no-observed-adverse-effect level (NOAEL) for histopathological injury in mice was 4.5 ppm for 2-chloronitrobenzene and 6 ppm for 4-chloronitrobenzene; a NOAEL was not determined for rats.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0272-0590
pubmed:author
pubmed:issnType
Print
pubmed:volume
30
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
75-92
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Thirteen-week inhalation toxicity of 2- and 4-chloronitrobenzene in F344/N rats and B6C3F1 mice.
pubmed:affiliation
National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA.
pubmed:publicationType
Journal Article