Spontaneous Rhabdomyosarcoma in a Common Marmoset ( Callithrix jacchus ).

The common marmoset (Callithrix jacchus) is now widely used in various research fields, including toxicology. However, information about the background pathology of this species is scarce. Here, we report a case of rhabdomyosarcoma that spontaneously occurred in a common marmoset.

Cystic cholangioma in the thoracic cavity of a rat.

A female congenic rat produced by repeated backcrossing of Nihon rats, a model for hereditary renal cell carcinoma, to Brown Norway rats was necropsied at 24 months of age. At necropsy, a white mass about 1 centimeter in size was observed in the thoracic cavity, and the mass partly adhered to the esophagus and the diaphragm. Histologically, the mass was clearly circumscribed by connective tissue, and consisted of neoplastic cuboidal epithelial cells that showed cystic tubular proliferation.

Immunohistochemical and ultrastructural analyses of cytoplasmic blood plasma inclusions of rat hepatocytes.

In the present study, we investigated the histological, immunohistochemical and ultrastructural characteristics of cytoplasmic blood plasma inclusions that spontaneously occurred in a rat liver. Histologically, a number of cytoplasmic inclusions were observed in the liver of an 8-week-old female SD rat. These inclusions were strongly positive for PAS staining and resistant to diastase digestion.

Spontaneous fibrosarcoma with pleomorphic appearance in an aged brown norway rat.

An 18-month-old male Brown Norway (BN) rat showed a grayish-white subcutaneous mass in the right cheek. Histologically, the mass was composed of highly pleomorphic cells producing collagen. Immunohistochemical analysis showed that the tumor cells were strongly positive for vimentin and partially positive for Ki-67; however, they were negative for ED-1, ED-2, S-100, cytokeratin, desmin and myoglobin.

Hyaline glomerulopathy with tubulo-fibrillary deposits in young ddY mice.

Hyaline glomerulopathy with tubulo-fibrillary deposits was observed in two young female ddY mice. One of the mice showed gross systemic edema and bilateral enlargement and pale color of the kidneys, whereas no significant gross findings were noted in the other mouse. Microscopically, a large number of the glomeruli in both mice were enlarged because of diffuse and global deposition of amorphous eosinophilic materials.

The First Case of Feline Infectious Peritonitis-like Pyogranuloma in a Ferret Infected by Coronavirus in Japan.

A male ferret, which was purchased from abroad at 9 months of age, had shown significant weight loss starting at 13 months of age. The ferret subsequently showed decreasing motor activity and recumbency and was euthanized at 14 months of age. At necropsy, a white, quail egg-sized mass was found in the mesentery.

Long-term treatment with ranirestat (AS-3201), a potent aldose reductase inhibitor, suppresses diabetic neuropathy and cataract formation in rats.

We investigated the chronic functional and histopathological changes in the sciatic nerve and lens of streptozotocin (STZ)-diabetic rats and evaluated the preventive effects of ranirestat (AS-3201), a potent aldose reductase inhibitor, on these changes. Sorbitol levels in the sciatic nerve and lens, motor nerve conduction velocity (MNCV), and development of cataracts were measured in STZ-diabetic rats given a ranirestat-admixed diet (0.0005%) for 35 weeks.

Gene expression analysis of the rat testis after treatment with di(2-ethylhexyl) phthalate using cDNA microarray and real-time RT-PCR.

To investigate the effects of di(2-ethylhexyl) phthalate (DEHP) on gene expression in rat testis, 6-week-old male Sprague-Dawley rats were given a single oral dose of 20 or 2000 mg/kg and euthanized 3, 6, 24, or 72 h thereafter. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells were significantly increased in the testis at 24 and 72 h after the exposure to 2000 mg/kg of DEHP. On cDNA microarray analysis, in addition to apoptosis-related genes, genes associated with atrophy, APEX nuclease, MutS homologue (E.

Mutation and overexpression of the transgene in ethylnitrosourea-induced tumors in mice carrying a human prototype c-Ha-ras gene.

To investigate mechanisms underlying accelerated carcinogenesis in mice carrying a human prototype c-Ha-ras gene (rasH2 mouse), mutations and the expression profile of the transgene were evaluated in 14 tumors induced by a single injection of ethylnitrosourea (ENU), with or without additional beta-estradiol 3-benzoate (EB) treatment. Although no codon 12 mutations were detected, changes in codon 61 were evident in all lung adenocarcinomas, skin squamous cell carcinomas and forestomach squamous cell carcinomas examined. The mRNA levels of the transgene in these lesions were also elevated 1.

Interlaboratory comparison of short-term carcinogenicity studies using CB6F1-rasH2 transgenic mice.

In order to evaluate a short-term carcinogenicity testing system using CB6F1 -Tg rasH2 (rasH2-Tg) mice carrying a human prototype c-Ha-ras gene, 26-week studies were conducted in 12 different facilities as a part of an International Life Science Institute Health and Environmental Science Institute (ILSI HESI) international collaborative project. In each study N-methyl-N-nitrosourea (MNU) was administered to a separate group of rasH2-Tg mice by single intraperitoneal injection (75 mg/kg) as a positive control. We herein have summarized the mortality, body weight change, and neoplastic and nonneoplastic lesions detected in these positive control groups as representative historical positive control data.

Overexpression of the peroxisome proliferator activated receptor alpha or the human c-Ha-ras transgene is not involved in tumorigenesis induced by di(2-ethylhexyl)phthalate in rasH2 mice.

The mRNA profiles for peroxisome proliferator activated receptor (PPAR) alpha and human c-Ha-ras genes were determined by real-time semi-quantitative polymerase chain reaction analysis of hepatocellular adenomas induced by di(2-ethylhexyl)phthalate (DEHP) in transgenic mice carrying a human prototype c-Ha-ras gene (rasH2 mice). The mRNA levels were essentially equal in hepatocellular adenomas and adjacent non-neoplastic hepatocytes, in spite of a remarkable elevation in the cell proliferation index in tumors determined by anti-Ki-67 immunohistochemistry. From the results, it is concluded that overexpression of PPARalpha or the transgene is not associated with the liver tumorigenesis induced by DEHP in rasH2 mice.

In vivo administration of a nuclear transcription factor-kappaB decoy suppresses experimental crescentic glomerulonephritis.

Glomerular expression of cytokines, interleukin-1 (IL-1), and tumor necrosis factor-alpha (TNF-alpha), together with leukocytic infiltration, are prominent features in crescentic glomerulonephritis. Because these cytokines are targets for nuclear transcription factor-kappaB (NF-kappaB), the use of NF-kappaB decoy oligodeoxynucleotide (ODN) treatment was evaluated in an experimental disease model. Crescentic glomerulonephritis was induced in primed Wistar rats by injection of sheep antiglomerular basement membrane serum.