The relationship between x-ray induced chromosome aberrations
and x-ray induced embryonic abnormalities was studied. Golden
hamsters were irradiated during four stages of gestation: the blastocyst
stage, 4.5 days post-copulation; the primitive streak stage, 6.5
days post-copulation; the organogenesis stage, 9.5 days post-copulation;
and the period of fetal growth, 11.5 days...
Throughout most of the developed world, surgical sterilization via gonadectomy has become a common tool for combating the overpopulation of unwanted dogs as well as to eliminate the risk of reproductive diseases in pet dogs. In the dog as in other normal adult mammal, the hypothalamus secretes gonadotropin-releasing hormone (GnRH),...
Zebrafish (Danio rerio) have become an increasingly important model organism for cancer research. There are several cancer models in which neoplasms are induced chemically or genetically. However, spontaneous (unknown etiology) neoplasms are rather common in zebrafish, particularly in older fish. For over a decade, spontaneous intestinal neoplasia and preneoplastic intestinal...
Cystic ovarian disease (COD) is an anovulatory condition in cattle
that afflicts between 6-18% of all dairy cows in the US. Ovulation is
dependent on the plasminogen activator (PA) family of proteases
and protease inhibitor for proteolysis, culminating in follicular rupture.
Failure of the follicle to ovulate suggests an aberration...
Suspensory apparatus breakdown and hyperextension of the metacarpophalangeal and metatarsophalangeal (fetlock) joints is a common condition in the llama and has been observed in llamas of all ages. Llama breeders refer to the condition as "down in the pasterns" or "down in the fetlocks." The condition can result in debilitating...