Cataract was induced by a single intraperitoneal injection of 100 mg/kg N-methyl-N-nitrosourea (MNU) to 0-, 5-, 10-, 15-, or 20-day-old male and female Sprague-Dawley rats. In day 0, 5, 10, and 15 MNU-treated rats, mature cataracts were constantly seen 7, 14, 14, and 30 days after dosing, respectively. In the day 20 MNU-treated rats, only subcapsular cataract was seen 30 days after dosing. Therefore, the rats exposed to MNU at an earlier age caused cataract more rapidly and severely. In the day 0 MNU-treated rats, 7-methyldeoxyguanosine DNA adduct was detected in the lens epithelial nuclei 12 hours after MNU dosing, followed by apoptosis, which was confirmed by morphology, by TUNEL signals, and by DNA ladder and peaked 3 days after MNU dosing. In the apoptosis cascade, upregulation of Bax, downregulation of Bcl-2, and increased CPP32 protease (caspase-3) activity were seen 12 hours after MNU dosing. Therefore, the pathogenesis of MNU-induced cataract was associated with DNA adduct formation in the lens epithelial cell nuclei leading to apoptosis by upregulation of Bax protein, downmodulation of Bcl-2 protein, and activation of caspase-3.

Animals↗

PubMedDate not supplied

Spontaneously occurring mammary adenocarcinoma in a 10-wk-old female rat.

A spontaneous mammary adenocarcinoma was detected in a 10-wk-old female virgin Sprague-Dawley rat in a subacute toxicity study for safety assessment. The rat was sacrificed according to the study schedule at 23 wk of age and was subjected to complete necropsy. Gross pathological examination revealed that the tumor had reached 20 x 35 x 45 mm. It was settled in the right posterior abdominal subcutaneous tissue and had not invaded the surrounding tissues. Histopathologically, it was diagnosed as a typical mammary adenocarcinoma of rats. In our literature search, we found no previous reports of spontaneous adenocarcinomas of the mammary gland in such a young rat. Therefore, attention should be paid to the fact that mammary adenocarcinomas can occur spontaneously at an early age in rats.

Adenocarcinoma↗

PubMedDate not supplied

Congenital intrahepatic arteriovenous fistulae in a young beagle dog.

Congenital intrahepatic arteriovenous fistulae, a rare hepatic vascular anomaly, in an 8-mo-old female beagle dog was investigated. The animal showed anorexia, repeated vomiting, hemorrhagic diarrhea, and jaundice for approximately 2 wk. There was mild to severe increase of serum alkaline phosphatase, glutamic-oxalacetic transaminase, glutamic pyruvic transaminase, total cholesterol, total bilirubin, and gamma-glutamyl transpeptidase. Macroscopically, the main abdominal organs showed hemorrhagic edema together with bloody ascites. Other characteristic findings were severe hepatic atrophy (right medial, quadrate, left medial, and lateral lobes) with multiple vascular cysts and compensatory hypertrophy of the other lobes. The cystic vessels seemed to extend from the proper hepatic arteries and their branches but were indistinguishable from the portal vein. Histopathologically, the atrophied hepatic lobes were characterized by wide, fibrous septa containing severe hyperplasia and anastomosis of the arteriolae and venulae and proliferation of bile ducts.

Animals↗

PubMedDate not supplied

[A clinical study of secondary osteoporosis induced by endocrine therapy for prostate cancer].

PURPOSE: There is one of the big problems that endocrine therapy for prostate cancer causes to induce secondary osteoporosis. The risk factors and future treatments for osteoporosis were investigated. MATERIALS AND METHODS: 31 patients treated with luteinizing hormone releasing hormone agonists (LHRH-a) or combination of chlormadinone acetate (CMA) and LHRH-a, and 19 patients with no treatments for prostate cancer were included in the analysis. Lumber spine bone mineral density (BMD) was measured by quantitative computed tomography. RESULTS: Aging had much influence on decreases of BMD than the other risk factors (p < 0.01). There were statistically decreases of BMD in the patients with CMA + LHRH-a compared with no treatments (p < 0.05). Adrenal androgen which had an important role of maintenance in BMD was statistically decreased by the administration of CMA (p < 0.01). CONCLUSIONS: Measurement of BMD before endocrine therapy is necessary for the patients with prostate cancer. It is important for the patients with decreases of BMD that CMA is not combined or the therapy for osteoporosis is preventively employed.

Aged↗