Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1 Pt 1
pubmed:dateCreated
1990-8-8
pubmed:abstractText
Time trends for growth, body weight, survival and tumor prevalences in 144 diet control groups with a total of 5,184 male F344/N rats and 146 diet control groups with a total of 5,289 female rats of NCI-NTP 2-yr chemical carcinogenicity studies started during an 11-yr period (1971 to 1981) in 11 toxicology testing laboratories were evaluated. Male and female rats in more recent studies grew faster and attained a higher body weight than rats from earlier studies. Survival of males showed a significantly decreasing trend over time, which may have been related to diseases associated with increasing body weight, prevalence of leukemia and changes in criteria for euthanasia of moribund animals. The time trend for survival of females was not significant. There were highly significant (p less than 0.001) positive time trends for prevalences of leukemia, anterior pituitary tumors and thyroid C-cell tumors in both sexes, adrenal pheochromocytomas in males and mammary tumors and endometrial stromal polyps in females. The prevalence of mammary tumors in females and pituitary tumors in males had a highly significant (p less than 0.01) positive association with body weight. Histological reevaluation of tumor prevalences in approximately 250 rats of each sex at each of 4 different time periods indicated that changes in diagnostic criteria may have contributed to but could not totally explain the increased prevalence of leukemia. Changes in diagnostic criteria and the amount of tissue examined may have contributed to the increased prevalence of anterior pituitary tumors in both sexes and adrenal pheochromocytomas in males. Interlaboratory variability and changes in diet may also have contributed to the time-related trends.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0192-6233
pubmed:author
pubmed:issnType
Print
pubmed:volume
18
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
61-70
pubmed:dateRevised
2009-7-1
pubmed:meshHeading
pubmed-meshheading:2362988-Adrenal Gland Neoplasms, pubmed-meshheading:2362988-Animals, pubmed-meshheading:2362988-Body Weight, pubmed-meshheading:2362988-Carcinogens, pubmed-meshheading:2362988-Female, pubmed-meshheading:2362988-Leukemia, Experimental, pubmed-meshheading:2362988-Male, pubmed-meshheading:2362988-Mammary Neoplasms, Experimental, pubmed-meshheading:2362988-Neoplasms, Experimental, pubmed-meshheading:2362988-Pheochromocytoma, pubmed-meshheading:2362988-Pituitary Neoplasms, pubmed-meshheading:2362988-Prevalence, pubmed-meshheading:2362988-Rats, pubmed-meshheading:2362988-Rats, Inbred F344, pubmed-meshheading:2362988-Rats, Inbred Strains, pubmed-meshheading:2362988-Survival Rate, pubmed-meshheading:2362988-Thyroid Neoplasms, pubmed-meshheading:2362988-Time Factors, pubmed-meshheading:2362988-Uterine Neoplasms
pubmed:year
1990
pubmed:articleTitle
Growth, body weight, survival, and tumor trends in F344/N rats during an eleven-year period.
pubmed:affiliation
National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina.
pubmed:publicationType
Journal Article