bromochloroacetic-acid and Rodent-Diseases

This report is the first description of a spinal epidermoid cyst (EC) in a SJL mouse and gives an overview on the occurrence of ECs in animals including dogs, horses, mice and rats. The EC was not detected grossly and the mouse did not display clinical signs or an altered rotarod performance. Microscopically, there was an oval cyst lined by stratified squamous epithelium that was attached to the dorsolateral meninges and caused moderate compression of the adjacent lumbar spinal cord. ECs in mice and rats are mainly located in the caudal part of the spinal cord with a variable, strain-dependent occurrence. ECs in mice and rats are not associated with clinical signs and can be interpreted as incidental findings.

Topics: Animals; Central Nervous System Diseases; Dogs; Epidermal Cyst; Female; Incidental Findings; Keratins; Lumbar Vertebrae; Meninges; Mice; Mice, Inbred Strains; Motor Activity; Rats; Rodent Diseases; Species Specificity; Spinal Cord Compression

Mammary tumors that spontaneously occurred in domestic Djungarian hamsters (Phodopus sungorus) were histologically examined. Forty-five mammary tumors included 14 adenomas, 18 adenocarcinomas, 1 lipid-rich carcinoma, 2 adenoacanthomas, 2 malignant adenomyoepitheliomas, 1 benign mixed tumor, and 7 "balloon cell" carcinosarcomas. The latter 4 types were newly recognized neoplasms in Djungarian hamsters. The relatively high incidence of spontaneous mammary carcinosarcomas in domestic Djungarian hamsters is intriguing. Carcinosarcomas exhibited anomalous histological features made up of a mixture of glandular cells, polygonal cells (including "balloon cells"), and sarcomatous spindle cells in varying proportions. Transitional features from glandular cells to polygonal cells and subsequently to sarcomatous spindle cells were observed. Using immunohistochemistry, we observed that glandular cells exhibited an epithelial phenotype (cytokeratin(+)/vimentin(-)), spindle cells exhibited a mesenchymal phenotype (cytokeratin(-)/vimentin(+)), and polygonal cells exhibited an intermediate phenotype (cytokeratin(+)/vimentin(+)). Reduction or loss of β-catenin expression and gain of S100A4 expression were observed in polygonal and spindle cells. The polygonal cell population included a varying number of characteristic cells that were expanded by large intracytoplasmic vacuoles. Electron microscopy revealed that these "balloon cells" had large cytoplasmic lumens lined by microvilli. These observations suggest that epithelial-mesenchymal transition may account for the pathogenesis of mammary carcinosarcomas in Djungarian hamsters.

Topics: Adenocarcinoma; Animals; beta Catenin; Carcinoma; Cricetinae; Epithelial-Mesenchymal Transition; Female; Immunohistochemistry; Keratins; Mammary Neoplasms, Animal; Phodopus; Rodent Diseases; Vimentin

Spontaneous salivary gland tumors in rats are rare. The authors report a poorly differentiated carcinoma of a submandibular gland in a ten-week-old rat that was positive for vimentin. Microscopically, the neoplastic cells showed a diffuse growth pattern in most areas of the tumor mass and a nestlike structure in a part of the peripheral area. Immunohistochemically, the cells were positive for keratin and vimentin but not for alpha-smooth muscle actin. Ultrastructurally, desmosome-like structures were observed. Based on these findings, the tumor was diagnosed as a poorly differentiated carcinoma. The origin of the neoplastic cells would be either acinar or ductal cells. This suggests that acinar or ductal cells have the potential to transform into vimentin-expressing cells.

Topics: Animals; Carcinoma; Keratins; Male; Rats; Rats, Sprague-Dawley; Rodent Diseases; Submandibular Gland Neoplasms; Toxicity Tests; Vimentin

An adenocarcinoma in the seminal vesicles of a 15-month-old male Wistar rat from a 30-month inhalation study is described. The rat was killed because of cachexia, apathy and a large palpable mass in the abdominal cavity. Macroscopic examination of the abdominal cavity revealed a 3.8 cm x 3.2 cm yellow-grey to pink mass, firm to soft in consistency. The cut section revealed cystic spaces. Histologically, the mass consisted of epithelial cells arranged in glandular and solid patterns with abundant amounts of connective tissue. Epithelial tumour cells were round-to-cylindrical with round-to-oval basophilic nuclei and one or two prominent nucleoli and a distinct eosinophilic cytoplasm. The glandular structure contained clusters of macrophages in their lumen with eosinophilic cytoplasm and indented nuclei. Extensive necrosis and reactive inflammation were present. The histological features of the small nodules in the pancreas and on the surface of the liver, rectum and urinary bladder resembled those of the primary tumour in the seminal vesicles. Based on these criteria, the neoplasm (mass) was diagnosed as an adenocarcinoma of the seminal vesicles. The immunohistological examination confirmed the diagnosis, i.e. immunostaining was positive for cytokeratins (4, 7, 14, 15, 18, and 19), vimentin, PCNA, and ED(1).

Topics: Adenocarcinoma; Animals; Fatal Outcome; Genital Neoplasms, Male; Immunohistochemistry; Keratins; Male; Rats; Rats, Wistar; Rodent Diseases; Seminal Vesicles

We found a novel recessive mutation in an inbred strain, INT, that was derived from an ICR closed colony. Mice homozygous for this mutation are identified by severe anemia, dysgenesis and neonatal death. This mutation was tentatively named int. Intercrosses of int heterozygotes (+/int) and the flaky skin heterozygotes (+/fsn) resulted in abnormal mice (int/fsn heterozygotes) showing anemia and flaky skin with the expected frequency for autosomal recessive mutation. The int gene was therefore named fsn(Jic) as an allele of the fsn locus on chromosome 17. We carried out phenotype analyses using B6.INT- fsn(Jic) mice to observe phenotypes of blood and skin in the embryonic and neonatal stages. Discrimination of fsn(Jic) embryos from normal embryos was performed by an indirect diagnosis of the fsn(Jic) gene using the D17Mit130 microsatellite marker tightly linked to the fsn locus. The number of fetal nucleated RBC of normal embryos decreased gradually to 17.5 dpc, but that of the abnormal embryos decreased to 14.5 dpc followed by a gradual increase to 17.5 dpc. Skin of fsn(Jic) embryos did not show any abnormalities and expressed cytokeratins normally as skin epithelial cell markers at each embryonic stage (15.5 dpc to 18.5 dpc). Time differences in the appearance of the different phenotypes observed in various tissue and organs of fsn homozygotes suggest they are caused by expression of the fsn gene at different developmental stages.

Topics: Alleles; Anemia, Hypochromic; Animals; Animals, Newborn; Biomarkers; Chromosome Mapping; Epithelial Cells; Erythroblasts; Erythrocyte Count; Female; Gene Expression Regulation, Developmental; Genes, Recessive; Keratins; Male; Mice; Mice, Inbred ICR; Mice, Mutant Strains; Microsatellite Repeats; Phenotype; Rodent Diseases; Skin Diseases, Papulosquamous

Oval cells which appear in the liver after hepatic injuries are suspected to be progenitor cells for both hepatocytes and bile duct cells. Oval cell isolated from the livers of the hamsters treated with diethylnitrosamine and 2-acetylaminofluorene and infected with Clonorchis sinensis (CS). cultured for 2 weeks and evaluated for differentiation and plasticity by electron microscopy and immunohistochemistry. In the CS-uninfected group, glycogen granules and peroxisomes were noted in the cells that were cultured for 2 weeks. Starting at 1 week postculture, immunoreactivity of the cells to cytokeratin 19 markedly decreased but that to albumin and alpha-fetoprotein gradually increased. This means that oval cells isolated from hamsters that were not infected with CS differentiated toward hepatocyte lineage. However, in the CS-infected group, cultured cells contained numerous rough endoplasmic reticulum and showed immunoreactivity that was generally in reverse to that of CS-uninfected group, meaning that cells isolated following CS infection were primed by CS and differentiated toward bile duct cell lineage. The results of this study suggested that oval cells are indeed bipolar progenitor cells for hepatocytes and bile duct cells and can differentiate toward either lineage depending upon the priming factor.

Topics: 2-Acetylaminofluorene; Albumins; Alkylating Agents; alpha-Fetoproteins; Animals; Carcinogens; Clonorchiasis; Clonorchis sinensis; Cricetinae; Diethylnitrosamine; Immunohistochemistry; Keratins; Liver; Liver Diseases, Parasitic; Male; Mesocricetus; Microscopy, Electron; Rodent Diseases

A malignant basal cell tumor was found in the skin of the abdomen of a female Djungarian hamster of unknown age and weighing 40 g. Histologically, the tumor mass was composed of cells resembling the basal cells of the epidermis, and these cells exhibited solid type proliferation. In the tumor tissue and necrotic foci, horn cysts were observed. Immunohistochemically, cytokeratin was present in the tumor cells and horncysts. By electron microscopic examination, the tumor cells had scanty cell organelles and a few desmozomes. This paper describes a rare malignant basal cell tumor in a Djungarian hamster.

Topics: Animals; Cell Division; Cricetinae; Female; Keratins; Microscopy, Electron; Neoplasms, Basal Cell; Phodopus; Rodent Diseases; Skin Neoplasms

Mucoepidermoid carcinomas in two mice were investigated histologically, immunohistochemically and ultrastructurally. The neoplastic cells showed divergent differentiation into periodic acid-Schiff-positive mucous cells, keratin-positive squamous cells, and cells with both mucous granules and sheaves of tonofilaments. Gland formation and keratinization were not observed. At the periphery of tumour cell nests, some cells were immunolabelled for smooth muscle actin or contained concentrated thin filaments, and these observations were interpreted to indicate that murine mucoepidermoid carcinomas are associated with both myoepithelium and duct epithelium.

Topics: Actins; Animals; Carcinoma, Mucoepidermoid; Female; Immunohistochemistry; Keratins; Mice; Mice, Inbred BALB C; Microscopy, Electron; Rodent Diseases; Submandibular Gland Neoplasms

Long-Evans (Eker) rats carry a mutation that predisposes them to develop spontaneous renal cell tumors of two morphologic patterns: solid chromophilic masses or cystic lesions lined by eosinophilic cells. Previous studies have suggested that these tumors arise from the proximal tubules. In the present study, lectin-binding characteristics and cytokeratin expression of various stages of hereditary rat renal epithelial neoplasia were examined to localize the portion of the nephron from which tumors arise. Lectin-binding histochemistry has been used as a marker of cell surface glycoprotein expression, thought to be important in the differentiation of benign from malignant epithelial lesions and in the determination of their cell of origin. The presence or absence of keratin intermediate filaments in the rat nephron has been used to identify nephron segments. The polyclonal antibody to high- and low-molecular-weight cytokeratin stained the cells of the collecting ducts but not the proximal or distal tubules. Binding to the proximal tubules by the lectins Conavalia ensiformis (Con A), Dolichas biflorus, Ricinus communis (RCA-1), and Triticum vulgare and to the distal tubules by Con A, RCA-1, Arachis hypogaea (PNA) with and without neuraminidase, and the antibody for cytokeratins was demonstrated. The lectin binding and cytokeratin staining patterns of rat hereditary renal cell carcinoma, adenoma and the preneoplastic lesions of atypical tubules and hyperplasias suggest that cystic adenomas arise from the distal nephron, principally the collecting duct, whereas the solid atypical tubules, hyperplasias, and adenomas arise from the proximal nephron, principally the proximal tubule.

Topics: Adenoma; Animals; Biomarkers, Tumor; Carcinoma, Renal Cell; Concanavalin A; Histocytochemistry; Hyperplasia; Immunohistochemistry; Keratins; Kidney Neoplasms; Kidney Tubules, Distal; Kidney Tubules, Proximal; Lectins; Male; Plant Lectins; Precancerous Conditions; Rats; Rodent Diseases; Wheat Germ Agglutinins

Two of five male Sprague-Dawley rats with hepatic tapeworm cysts developed large multinodular fibrosarcomas. Fibrosarcomas envelope tapeworm cysts, invaded the serosa of multiple organs, and extended through the diaphragm into the pleural cavity. Light microscopy, immunohistochemistry, and electron microscopy supported the diagnosis of fibrosarcoma. The parasites were identified as Cysticercus fasciolaris, the larval stage of Taenia taeniaeformis. The development of sarcomas in rats induced by Taenia sp. is thought to be attributable to the chronic inflammatory reaction of the capsule. There are parallels between these and other tumors occurring in mice and cats with suggested chronic inflammatory etiologies.

Topics: Animals; Cysticercosis; Cysticercus; Desmin; Fibrosarcoma; Immunohistochemistry; Keratins; Liver; Liver Diseases, Parasitic; Liver Neoplasms; Male; Microscopy, Electron; Rats; Rats, Sprague-Dawley; Rodent Diseases; Vimentin

The purpose of this study was to characterize a spontaneous disease condition causing hyperkeratosis in nude mice and to explore the etiologic role of a particular species of coryneform bacteria in this disease, colloquially known as "scaly skin disease." The study was divided into two parts. In the first phase, a series of inoculation experiments was conducted with a field isolate of the coryneform species used to study the clinical and histopathologic development of the disease syndrome. Athymic nude mice (4 to 5 weeks old) were inoculated on the skin of the back with a suspension of a pure culture of the coryneform bacterium that had been isolated from a field case. The culture was applied with a sterile cotton swab in concentrations varying from 6.1 x 10(4)/ml to 5.0 x 10(7)/ml. All inoculated mice became persistently infected throughout the 33 days of the experiment. Clinically evident hyperkeratosis in inoculated animals developed more frequently in mice housed in a microisolator cage than in a semi-rigid isolator and more frequently in mice inoculated with higher numbers of organisms. In all animals in which hyperkeratosis developed, it was first noted on day 7 after inoculation. The second series of experiments was designed to determine the success of various housing methods in excluding the infection, mechanisms of transmission, susceptibility of other stocks and strains of mice to the organism, and whether the other strains might serve as a source of the organism. Results of the study in various strains indicated that both immunocompetent and immunodeficient mice, whether glabrous or hirsute, could be infected with the organism, but only glabrous animals developed hyperkeratosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Anti-Bacterial Agents; Corynebacterium; Corynebacterium Infections; Epidermis; Fatty Acids; Female; Keratins; Keratosis; Lactams; Macrolides; Male; Mice; Mice, Nude; Microbial Sensitivity Tests; Rodent Diseases; Skin Diseases, Bacterial

Topics: Alcian Blue; Animals; Cricetinae; Hyaluronoglucosaminidase; Immunohistochemistry; Keratins; Male; Mesocricetus; Mesothelioma; Periodic Acid-Schiff Reaction; Peritoneal Neoplasms; Rodent Diseases; Staining and Labeling; Vimentin

Myoepitheliomas are subcutaneous tumors that arise from myoepithelial cells of various exocrine glands. In a retrospective study of 142 tumors observed over a period of 3 years, myoepitheliomas occurred spontaneously in A/HeJ, A/J, BALB/cJ, BALB/cByJ, LLC.A/Ckc, and NOD/Lt inbred strains of mice. Tumors presented primarily in the subcutaneous tissues of the ventral neck (74% of the myoepitheliomas evaluated) but were observed in several other subcutaneous locations, including the head, perineum, and ventral abdomen. These areas were adjacent to salivary, mammary, clitoral, preputial, and Harderian glands. Forty myoepitheliomas were tested by the avidin-biotin complex technique with a panel of antisera specific for mouse keratins, intermediate filaments, and other cytoskeletal proteins to determine the cell type from which this neoplasm originated. Antibodies directed against the specific mouse keratins K5, K6, and K14, and a broadly cross-reactive cytokeratin antibody stained acinar and ductal myoepithelial cells in normal mammary, salivary, and Harderian glands, and neoplastic cells in all cases. Antisera directed against a smooth muscle actin (anti-alpha-sm-1) stained acinar myoepithelial cells of the glands and vascular smooth muscle but neither ductular myoepithelial cells nor tumor cells. This supports the notion that these tumors originate from extraglandular ductular myoepithelial cells. Southern blots, prepared from DNA extracted from nine myoepitheliomas, did not show restriction fragment length polymorphisms when mouse mammary tumor virus (MMTV) cDNA or Int-1 genomic DNA probes were used; this implies that a retrovirus is not the etiologic agent.

Topics: Age Factors; Animals; Blotting, Southern; DNA, Neoplasm; Female; Fluorescent Antibody Technique; Immunohistochemistry; Incidence; Keratins; Male; Mice; Mice, Inbred Strains; Microscopy, Electron; Myoepithelioma; Retrospective Studies; Rodent Diseases; Skin Neoplasms

Hepatoblastomas from B6C3F1 and BALB/c mice were examined by light and electron microscopy and by immunohistochemical reactions for alpha-fetoprotein, keratin, and vimentin. Tumors occurred in one group of a chronic bioassay for the interaction of diet, genetic strain, and the carcinogen, 2-acetylaminofluorene. Tumors had several populations (including epithelial and mesenchymal cells) in various stages of differentiation. Neoplastic epithelial cells had features of embryonal hepatocytes, such as sparse cytoplasmic organelles, absence of glycogen, abundant free ribosomes, occasional bile canaliculi, and peroxisome-like dense bodies. Embryonal fibroblast-like cells had pleomorphic and folded nuclei with prominent perinuclear chromatin and dispersed cytoplasmic organelles. Fibroblast-like cells were surrounded by bundles of collagen fibrils. Intermediate or transitional types of cells were seen. No tumor cells were immunoreactive for mouse alpha-fetoprotein (AFP) antibody, unlike those in hepatocellular adenomas or carcinomas. Epithelial and mesenchymal tumor cells contained intermediate filaments throughout the cytoplasm; some of these cells stained for keratin but not for vimentin. These findings suggest that mouse hepatoblastomas are derived from bipotential liver blastema cells and are composed of a mixture of several cell populations.

Topics: alpha-Fetoproteins; Animals; Immunohistochemistry; Keratins; Liver Neoplasms; Liver Neoplasms, Experimental; Mice; Mice, Inbred BALB C; Mice, Inbred Strains; Microscopy, Electron; Rodent Diseases; Vimentin

Topics: Alopecia; Animals; Cell Membrane; Cytoplasm; Glutaral; Histological Techniques; Keratins; Mice; Mice, Inbred Strains; Microscopy, Electron; Osmium; Rodent Diseases; Skin; Species Specificity; Staining and Labeling

Topics: Animals; Epithelium; Esophagus; Female; Keratins; Larva; Male; Mite Infestations; Mites; Mouth; Nymph; Rodent Diseases; Rodentia; Sebaceous Glands; Tongue