Unusually high incidence of spontaneous endometrial adenocarcinoma in aged virgin Fischer rats.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to T Waner.
Explore the source record for details and available documents.
The present report describes the morphological features of a spontaneous, bilateral, complex odontoma of the incisor teeth in an 87-week-old male Swiss mouse (Crl: CD-1(ICR)BR). This report constitutes the second report of an odontogenic tumour in a Swiss mouse and the first describing a bilateral complex odontoma in this strain of mouse. The report emphasizes the importance of thoroughly examining the oral cavity for dental tumours.
We observed an interstitial cell tumor in an 18-mo-old captive eland bull (Taurotragus oryx) in Tel Aviv, Israel. The histological description of the tumor in the eland was similar to that described in cattle; however, the appearance of a moderate amount of lipid vacuoles in the cytoplasm of the neoplastic cells was uncharacteristic for bovine interstitial cell tumors. The eland also had clinical signs of gynecomastia.
Explore the source record for details and available documents.
Two cases of squamous cell carcinoma arising from the perianal skin of aged female Sannen crossbred goats are described. The occurrence of a tumour in this specific location is very rare, and the presence of the identical tumour in two animals of the same herd is unusual.
A case of a spontaneous intratubular spermatic seminoma is described in a 98-wk-old Fischer-344 (F-344) rat. The differential diagnosis of spermatic seminoma from the other morphological forms of the tumor was based on the recognition of 3 cell types. The tumor cells were positive for S-100 antigen and cytokeratin. To the best of our knowledge, this is the second case of a seminoma reported in an F-344 rat and the first dealing with electron microscopic and immunohistochemical features of this tumor.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The variability of organ weight data in a series of 5 control groups of Sprague-Dawley rats was studied. Differences in body weight and organ weight data were detected between the studies. Attempts to reduce the variability of organ weights by using analysis of covariance or organ to brain weight ratios were only partially successful. Factors which may influence animals under controlled conditions and result in variability between studies are discussed. It is concluded that caution is needed when considering the use of organ weight background data as a means of comparison. The findings are in agreement with other fields of study in toxicological testing, and emphasize the importance of using a concurrent control for the purpose of comparison of data.
Using the model of oxodipine-induced gingival hyperplasia in beagle dogs, we investigated the collagen fibres of the hyperplastic gingiva by measuring the polarization colours from Picrosirius-red stained sections. The predominant polarization colours of the thick collagen fibres (1.6-2.4 microns diameter) of male oxodipine-treated dogs were greenish-yellow to yellow, while in controls and in female oxodipine-treated dogs, the same size fibres mostly appeared orange and red. These differences may be indicative of gender variation in the genesis of hyperplastic gingiva in calcium channel blocker treated dogs.
During a sub-chronic dermal toxicity study, hepatic and ocular toxicity were detected unrelated to the compound being tested. The changes in the liver were characterized by hepatic centrilobular degeneration and fibrosis due to chronic passive congestion. Clinical chemistry results confirmed the active hepatic damage and cholestasis. The ocular changes were limited to the retina where diffuse retinal atrophy was seen originating adjacent to the optic nerve and progressing centrifugally. It is suggested that as a consequence of the bandaging technique, a state of passive congestion and cholestasis resulted. The decrease in flow of bile acids to the intestine caused disturbances in vitamin E absorption. The deficiency of the antioxidant vitamin was responsible for the retinal changes seen.
The dietary administration of the calcium channel blocker oxodipine to Fischer (F344) rats for 12 and 30 months resulted in increased incidence of altered hepatocytic foci (AHF). As the Environmental Protection Agency (EPA) regards AHF as potentially precancerous it is important to accumulate experimental evidence which may negate this theory. In the case of oxodipine we proved that with dosages close to maximum tolerated dose (MTD) for prolonged periods no hepatic neoplasms were produced. The possible nature of such AHF is discussed.
Explore the source record for details and available documents.
Subchronic effects of oxodipine, a calcium channel blocker affecting the adrenal gland of the dog, are described. Thirteen wk of treatment at a high dose (24 mg/kg/day) of oxodipine resulted in drug-induced thickening of the zona glomerulosa and increased stimulation of its secretory activity. It is postulated that subchronic administration of oxodipine at this dosage resulted in a decrease in blood pressure, with uninterrupted stimulation of the adrenal zona glomerulosa to release aldosterone, causing an increase in the width of this portion of the gland involving cellular hyperplasia. Support for this indirect effect is found in the increased presence of renin granules in the juxtaglomerular apparatus.
Thionaphthene-2-carboxylic acid (TNCA) has been shown to decrease osteoclast-mediated bone resorption in vitro and has shown efficacy in animal models of hypercalcaemia of malignancy. In this study, the effects of TNCA on the tibial proximal epiphysis and the sternum have been quantified by image analysis in rats administered the drug orally for 90 days at 75, 125 or 250 mg/kg/day. The amount of bone in the subepiphyseal area and sternum was increased in a dose-related manner. TNCA exerted a biphasic effect on the height of the epiphyseal plate. It was stimulatory at the low dosage and inhibitory at the high dose. This study constitutes the first of its kind to demonstrate the in-vivo effect of TNCA on the bones of rats.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The report consists of a cytomorphological and ultrastructural description of a spontaneous rete testis adenocarcinoma observed in a 108-week-old Fischer 344 rat. This tumour is considered to be very rare in rats. Crucial evidence for the malignancy of this tumour was the penetration of a neoplastic gland into the tunica albuginea.