Myoepitheliomas in inbred laboratory mice.

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.     

Parasite infections in laboratory mice colonies

Problems dealing with common parasites--oxyurids, which affect laboratory mice colonies are discussed and reviewed. Their life histories, pathogenicity and immunity are examined. The attention is paid to the influence of age, sex, strain and status of the host in the infection. It is agreed that helminth infections are usually more severe in male than in female vertebrate hosts.     

Acidophilic macrophage pneumonia in laboratory mice

Acidophilic macrophage pneumonia, characterized by an accumulation of characteristic crystalloid-laden alveolar macrophages, was seen in 30/7,500 NMRI, 7/600 T x HT, 2/100 C57BL and in no cases of 1,500 CBA and 1,100 BALB/c mice. Histologically, there was a focal accumulation of large numbers of eosinophilic macrophages, generally associated with granulocytes. Macrophages could be mononucleate or multinucleate and had a crystalline cytoplasm. Free-lying crystals were sometimes observed. Ultrastructurally, macrophages had a cytoplasmic accumulation of needle-shaped and rhomboidal crystals, often showing a clear lattice structure with a repeat of 3-5 nm. The crystalloid inclusions may be derived from the breakdown products of granulocytes and appear similar to inclusions in macrophages in other parts of the hematopoietic system. That these inclusions are probably derived from eosinophils is based on the appearance within macrophages of structures resembling eosinophil granules at various stages of degradation and the similarity between the lattice repeat of the crystalloids and that of the crystalline core of the eosinophil granule. The crystalloid inclusions may be related to the Charcot-Leyden crystals found in human beings.     

Serodiagnosis of acute toxoplasmosis in macropods

The sera of 34 Australian macropods, the brains of which had been bioassayed for Toxoplasma gondii, were used to establish that a titre greater than 1/32 was significant for a direct agglutination test against toxoplasmosis. In addition, the concentration of 2-mercaptoethanol required to destroy the IgM fraction of macropod serum was confirmed in a modified direct agglutination test. To further validate the tests, the serological responses of three eastern grey kangaroos (Macropus giganteus) dosed orally with T. gondii oocysts and one M. giganteus injected with T. gondii cysts were studied. The tests were then used to investigate a diagnosis of acute toxoplasmosis in four Tasmanian pademelons (Thylogale billardierii) clinically suspected of acquiring toxoplasmosis naturally. One hundred and fifty-one Bennett's wallabies (Macropus rufogriseus rufogriseus) and 85 T. billardierii were also tested to determine the prevalence of acute toxoplasmosis of macropods in the wild. Four percent of M. r. rufogriseus and 1.2% of T. billardierii possessed T. gondii-specific IgM in their sera.     

Skeletal muscle rhabdomyosarcomas in inbred laboratory mice.

A total of 14 well differentiated rhabdomyosarcomas were diagnosed at necropsy in 10,000 mice. Of the 14 affected mice, ten were BALB/cJ, and there was one case each of A/HeJ, BALB/cByJ, C58/J, and C.B-17-scid/scid strains. Most often (10/14) tumors originated in the quadriceps muscles and metastases occurred in six cases. When submitted, affected mice were 2 to 8 months of age, with a mean age of 4 months. Tumor frequency for BALB/cJ mice was calculated to be 2.4/100,000 mice retained as breeders. No sexual dimorphisms were determined when data were correlated to actual numbers of each sex in the colony. All 14 primary tumors and metastases were positive by immunohistochemistry for the proteins pan myosin, sarcomeric actin, desmin, actin, and myosin, but were negative for smooth muscle actin, thus confirming the diagnosis. Using cell free homogenates of primary tumors, inoculated by intraperitoneal or intramuscular injection, tumors were not induced in either BALB/cJ or C58/J mice observed over a 22-week period. Southern blot analysis of DNA prepared from tumors and hybridized with a murine leukemia virus probe that recognizes both ecotropic and dualtropic viruses did not demonstrate viral genomic fragments in addition to those known to occur in each strain.     

Serodiagnosis of Lyme disease in UK dogs

Lyme disease is a chronic, multisystemic, inflammatory disorder of man and animals associated with infection by the tick-borne spirochaete, Borrelia burgdorferi. Lyme disease was recently reported for the first time in a dog in the UK (May and others 1990). Using an enzyme-linked immunosorbent assay (ELISA), we have performed a serological survey to investigate the prevalence of antibodies to B burgdorferi in UK dogs. The survey has shown that dogs from many areas in the UK have serum antibodies to B burgdorferi, that the presence of serum antibodies is associated with known exposure to ticks and that some dogs seropositive for B burgdorferi have clinical signs consistent with Lyme disease. High levels of serum anti-Borrelia antibodies are not diagnostic for canine Lyme disease, but, in association with appropriate clinical signs, they help to confirm the diagnosis in suspected cases.     

Serodiagnosis of Histophilus ovis-associated epididymitis in rams

An ELISA for the detection of antibodies to Histophilus ovis was used to evaluate the association of epididymal lesions in rams with serologic response to His ovis. Comparison of ELISA results for His ovis in groups of rams with epididymal lesions with ELISA results of clinically normal rams (control group) revealed a significant difference (P less than 0.01) between the control group and those rams from which His ovis was isolated. A significant difference (P less than 0.01) was noticed between the control group and rams with lesions from which an organism other than His ovis or Brucella ovis was isolated. Additionally, a significant difference (P less than 0.01) was noticed in ELISA results between the control group and affected rams from which no organism was recovered and in which the epididymal lesion was not limited to the head of the epididymis. A difference was not detected in the His ovis ELISA results between control rams and rams with lesions associated with a B ovis infection or rams from which no organism was recovered and in which the epididymal lesion was limited to the head of the epididymis. The serologic findings in our study suggest that His ovis is more important in the development of epididymitis in rams than culture results alone would indicate.     

Serodiagnosis of Fasciola gigantica infection in buffaloes

The agar gel precipitation test (AGPT), counter immunoelectrophoresis (CIEP) and indirect haemagglutination (IHA) were evaluated for the diagnosis of fascioliasis due to Fasciola gigantica in buffaloes. The sensitivity of these tests varied with the intensity of infection; and was greatest when the fluke burden in liver exceeded 100. CIEP detected 76.06% of infected sera and was most sensitive, followed by IHA which detected 68.37% of the infected sera. The AGPT was found to be least sensitive, detecting only 57.4% of the infected sera. Although these tests were limited by the occurrence of false-positive reactions, their use may be an aid for effective diagnosis of fascioliasis in buffaloes.     

小尾寒羊犬新孢子虫病血清学诊断

应用酶联免疫吸附实验,对民和县引进小尾寒羊224份血清样品进行了犬新孢子虫病的检测。结果,被检的224份血清中,检出犬新孢子虫抗体阳性血清16份,阳性率分别为7.14%。表明引入青海省的小尾寒羊中存在犬新孢子虫病。