Groups of 30 Wistar rats of each sex were treated with 2,2'-methylenebis(4-ethyl-6-tert-butylphenol) (MBEBP) in the diet at levels of 0, 0.03, 0.1 and 0.3% for up to 18 months. In both sexes, survival rates of treated groups were similar to those of the controls. Body weight gain was depressed (0.3% group in males, 0.1 and 0.3% groups in females). Slight anaemia (0.3% groups in both sexes) and increase of blood urea nitrogen (0.3% groups in both sexes) were observed. Histopathologically, vacuolization of the parathyroid gland cells (0.3% group in males and all treated groups in females) and degenerative changes of the kidney (0.1 and 0.3% groups in males) were observed. No neoplastic responses following MBEBP administration were noted. From these results, the no-observed-adverse-effect level (NOAEL) for MBEBP toxicity was estimated as 12 mg kg-1 body wt. day-1 in male rats. In female rats, the lowest-observed-adverse-effect level (LOAEL) was estimated as 15 mg kg-1 body wt. day-1.

Animals↗

PubMedDate not supplied

Immunohistochemical study of calpain-mediated alpha-crystallin proteolysis in the UPL rat hereditary cataract.

The UPL (Upjohn Pharmaceutical Limited) rat is a dominant hereditary cataract model that develops early-onset cataracts (E-type) in rats homozygous for the trait, and late-onset cataracts (L-type) in heterozygous rats. Using antibodies specific to the calpain-proteolyzed forms of alpha-crystallin, we determined their immunohistochemical localization of the L- and E-rat lenses. Immunoreactivity indicating the proteolyzed forms was detected and found restricted to degenerated lens fibers of the mature stage of the L-rat cataract. Lenses from E-rats, which have abnormally elongated lens fibers during the fetal period, had proteolyzed alpha-crystallin forms at 1 week of age. The results of this present study indicate that calpain-mediated proteolysis of alpha-crystallin occurred in the UPL rat lenses during cataract formation and that calpain may be an important factor in the development of complete lens opacification.

Animals↗

PubMedDate not supplied

Fine needle aspiration cytology of lipid-secreting carcinoma of the breast. A case report.

Fine needle aspiration (FNA) cytology of lipid-secreting carcinoma of the breast was performed on a 43-year-old woman who was admitted with a left breast tumor. Smears of the aspirate showed atypical cells that contained numerous large and small vacuoles in the cytoplasm and were diagnosed as adenocarcinoma of the breast. A modified radical mastectomy was performed under the diagnosis of breast carcinoma. A solid, yellowish, milky white, well-demarcated tumor was found in the resected specimen. Microscopically, hematoxylin and eosin staining revealed foamy and granular vacuoles in the cytoplasm of the tumor cells similar to those seen on the smears, which were positive for lipid staining. Electron microscopic examination also showed numerous intracytoplasmic lipid droplets in the tumor cells. This tumor was finally diagnosed as lipid-secreting carcinoma of the breast on the basis of histologic and electron microscopic features. Lipid-secreting carcinoma of the breast is rare, and only one recurrent case diagnosed by cytology in pleural and pericardial fluids has been described. Since the tumor cells originating in lipid-secreting carcinoma of the breast differ from ordinary breast carcinoma cells, FNA cytology is useful in diagnosing this neoplasm.

Adult↗