Papovaviral sialoadenitis in athymic nude rats

A wasting disease was found in 32 athymic nude rats. The rats had parotid sialoadenitis with intranuclear inclusion bodies in ductal and acinar epithelial cells. Other common lesions included bronchitis, bronchiolitis and secondary bacterial pneumonia. Less commonly, rhinitis and Harderian adenitis were seen. Intranuclear inclusions were also seen in bronchial epithelium of 1 rat, Harderian gland acini of 1 rat and laryngeal glands of 2 rats. Viral particles, averaging 45 nm in diameter, sometimes in crystalline arrays, were found in the nucleus of parotid epithelial cells. By the use of the avidin-biotin-peroxidase complex (ABC) immunoperoxidase technique, antibodies to disrupted SV40 virus (the group specific antigen of the polyomavirus (miopapovavirus) genus of the papovavirus family) reacted with intranuclear inclusions and cytoplasm of parotid epithelium and inclusions in lung and Harderian gland. The viral antigen did not cross react with antibodies to mouse polyoma, mouse K or disrupted bovine papilloma viruses.     

Natural killer activity in the rat. III. Characterization of transplantable large granular lymphocyte (LGL) leukemias in the F344 rat

Six transplantable large granular lymphocyte (LGL) tumor lines in F344 rats were examined for natural killer (NK) and antibody-dependent cell-mediated cytotoxicity. Tumor cells from all six lines were highly cytotoxic, even at low effector to target ratios, when tested against NK-susceptible targets, but were unreactive against an NK-resistant target (C58NT)D) and a macrophage-susceptible target (P815). Three lines showed significant levels of lysis against antibody-coated tumor cells. After in vivo transplantation, the levels of cytotoxicity steadily increased in three lines and decreased in one. The cytotoxic activity of one line (RNK-16) remained high through 12 transplant generations. Tumor cells injected i.p. spread via the lymphatics to regional lymph nodes, mediastinal nodes, blood, and eventually the bone marrow. Leukemia occurred concurrently with organ enlargement and increased levels of NK. Studies in (F344 X W/Fu)F1 rats clearly demonstrated that the cytotoxic cells from leukemic animals were the transplanted tumor cells themselves and not merely the activation of normal host LGL. These results demonstrate that naturally occurring, transplantable LGL leukemias are an easily obtainable and excellent source of materials for those studies requiring a large number of functionally active LGL.     

Expression of minute virus of mice structural proteins in murine cell lines transformed by bovine papillomavirus-minute virus of mice plasmid chimera.

Recombinant plasmids containing the genomes of both bovine papillomavirus type I and minute virus of mice (MVM) were constructed and used to transform mouse C127 cells. Transformed lines that express MVM gene products with high efficiency were isolated and characterized. These transformants synthesize large amounts of MVM structural polypeptides and spontaneously assemble them into empty virion particles that are released into the culture medium. These lines were, however, genetically unstable; they slowly generated subpopulations that failed to express MVM-specific proteins, and they possessed episomal DNA in which both MVM and bovine papillomavirus sequences were deleted or rearranged, or both. Clonal isolates of these transformants were also superinfectible by infectious MVM virus. Therefore, in spite of their instability, they should be useful host cell lines for transcomplementing mutations introduced into the MVM genome and for growing defective viruses as virions.     

Brain temperature measurements in rats: a comparison of microwave and ambient temperature exposures

In an effort to understand microwave heating better, regional brain and core temperatures of rats exposed to microwave radiation (2450 MHz) or elevated air temperatures were measured in two studies. In general, we have found no substantial evidence for temperature differentials, or "hot spots," in the brain of these animals. In the first study, after a 30-min exposure, no temperature differences between brain regions either after microwave or ambient air exposure were found. However, a highly significant correlation between brain and core temperatures was found and this correlation was the same for both microwave and ambient air heating. In the second study, time-temperature profiles were measured in rats exposed to either 30 mW/cm2 or 36.2 degrees C. In this study, the 30-min exposure period was divided into seven intervals and the change in temperature during each period was analyzed. Only the cortex showed significantly different heating rates between the air heating and microwave heating; however, this difference disappeared after the initial 5 min of exposure.     

Evaluating pedigree data. II. Identifying the cause of error in families with inconsistencies

Pedigree data can be evaluated, and subsequently corrected, by analysis of the distribution of genetic markers, taking account of the possibility of mistyping . Using a model of pedigree error developed previously, we obtained the maximum likelihood estimates of error parameters in pedigree data from Tokelau. Posterior probabilities for the possible true relationships in each family are conditional on the putative relationships and the marker data are calculated using the parameter estimates. These probabilities are used as a basis for discriminating between pedigree error and genetic marker errors in families where inconsistencies have been observed. When applied to the Tokelau data and compared with the results of retyping inconsistent families, these statistical procedures are able to discriminate between pedigree and marker error, with approximately 90% accuracy, for families with two or more offspring. The large proportion of inconsistencies inferred to be due to marker error (61%) indicates the importance of discriminating between error sources when judging the reliability of putative relationship data. Application of our model of pedigree error has proved to be an efficient way of determining and subsequently correcting sources of error in extensive pedigree data collected in large surveys.     

Identification of a large multigene family encoding the major sperm protein of Caenorhabditis elegans

DNA fragments corresponding to genes encoding the MSP of Caenorhabditis elegans sperm have been isolated by recombinant DNA techniques. Analyses of individual genomic clones suggest that there are multiple MSP genes that are dispersed in the genome. From restriction enzyme digests of genomic DNA fractionated and hybridized with an MSP complementary DNA probe, there appear to be more than 30 MSP genes in the genome. Despite the occurrence of this large dispersed multigene family, the MSP messenger RNA from both males and hermaphrodites is homogene in size. There are at least three different proteins of identical molecular weight but different isoelectric point that cross-react with anti-MSP antisera. Each protein is a primary translation product with no detectable post-translational modifications, suggesting that at least three of the MSP genes are expressed.     

Functional features of lymphocytes recovered from a human renal allograft

Lymphocytes recovered from a rejected human renal allograft were cultured in vitro for their ability to produce several soluble mediators associated with cellular hypersensitivity as well as a procoagulantlike material. In addition, their response in mixed lymphocyte culture was tested. These lymphocytes were of recipient origin by sex karyotyping. An alteration in their proliferative capacity could be demonstrated by an earlier response in mixed lymphocyte cultures although peak response was essentially unchanged. Cultured supernatants from recipient lymphocytes (recovered from the rejected kidney) contained several mediator activities—macrophage migration inhibitory factor, chemotactic factors for neutrophils and macrophages, a factor mitogenic for lymphocytes, as well as a procoagulant material. These findings extend previous work of others who have demonstrated the presence of lymphocytes infiltrating allografts by showing that these cells are immunologically reactive in vitro.