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Descriptions of NTP Study Types
Descriptions of NTP Study Types
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The basic parts of the study design are:
Necropsies
After weaning of F1 offspring, completion of any crossover or dominant lethal studies, and vaginal cytology assessment of F 0 females, all of the F0 animals are necropsied. The endpoints for this necropsy are weights of whole body, liver, kidneys, right testis, right epididymis, right cauda epididymis, prostate, seminal vesicles (with coagulating glands attached), and ovaries, as well as any other known target organs for the compound on test. The ovaries are fixed in Bouin's and retained in 70% ethanol for possible study. The vagina, cervix, and uterus are fixed in formalin, but not weighed. Testes are fixed in 4% buffered paraformaldehyde for <= 48 hrs, then transferred to PBS. Testes and epididymides are embedded in glycol methacrylate and stained with hematoxylin and periodic acid - Schiff's stain. Prior to necropsy, vaginal smears are recorded for 12 days. For males, additional endpoints include cauda epididymal sperm number and density, morphology, and motility, and testicular spermatid head count. After production of 3 F2 litters, all F1 animals are necropsied and weights of whole body, liver, kidneys, right and left testis, right and left epididymis, right and left cauda epididymis, prostate, seminal vesicles (with coagulating glands attached), and ovaries obtained. The ovaries are fixed in Bouin's and retained for possible study. Data are collected as for the F0 males and sperm motility data are gathered from all males undergoing necropsy using a computer-assisted semen analyzer.
Web page last updated on September 30, 2004
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