Longitudinal studies of immune function in cattle experimentally infected with bovine immunodeficiency-like virus and/or bovine leukemia virus

The effects of single or dual infection with bovine immunodeficiency-like virus (BIV) and/or, bovine leukemia virus (BLV) on bovine immune function were examined over a 4 year period. Holstein calves were infected with BIV (four calves), BLV (five calves), BIV and BLV (five calves), or sham inoculated (three calves). Lymphocyte blastogenesis to mitogens, seven tests of neutrophil function, and mononuclear cell subset analysis by flow cytometry (BoCD4, BoCD8, BoCD2, BoWC1, sIgM+, and monocytes) were performed at regular intervals to 49 months post-infection. These data were analyzed for main effects of each virus and interaction as a 2 x 2 factorial. BIV infected cattle had lower neutrophil antibody-dependent cell-mediated cytotoxicity and iodination responses during 2 of the 4 years post-infection (P < 0.05). BIV infection was not associated with any long-term significant changes in lymphocyte blastogenesis to mitogens or changes in mononuclear cell subset numbers in blood. There was a tendency for animals infected with BIV alone to have decreased lymphocyte blastogenic responses to mitogens, but this was not statistically significant. BLV infection caused an increase in total mononuclear cells with no dramatic shift in the relative proportions of the various subsets. Co-infection with BIV and BLV did not consistently cause a different response than either virus did individually. One BIV infected animal died of non-BLV lymphosarcoma 7 months after infection. All other animals had no unusual clinical signs. In summary, infection with BIV caused a significant, temporary decrease in neutrophil function with no consistent statistically significant alteration in lymphocyte blastogenesis or mononuclear cell numbers during the first 4 years after infection. BLV infection caused an increase in lymphocyte numbers, and there appeared to be no synergism between the viruses.     

Cellular localization of the chemokine receptor CCR5. Correlation to cellular targets of HIV-1 infection

The chemokine receptor CCR5 has recently been described as a co-receptor for macrophage-tropic strains of human immunodeficiency virus (HIV)-1. In this study, using a panel of monoclonal antibodies specific for human CCR5, we show by immunohistochemistry and flow cytometry that CCR5 is expressed by bone-marrow-derived cells known to be targets for HIV-1 infection, including a subpopulation of lymphocytes and monocyte/macrophages in blood, primary and secondary lymphoid organs, and noninflamed tissues. In the central nervous system, CCR5 is expressed on neurons, astrocytes, and microglia. In other tissues, CCR5 is expressed on epithelium, endothelium, vascular smooth muscle, and fibroblasts. Chronically inflamed tissues contain an increased number of CCR5+ mononuclear cells, and the number of immunoreactive cells is directly associated with a histopathological correlate of inflammatory severity. Collectively, these results suggest that CCR5+ cells are recruited to inflammatory sites and, as such, may facilitate transmission of macrophage-tropic strains of HIV-1.     

Extent of radial sarcomere coupling revealed in passively stretched cardiac myocytes

We report a simple method, the PinPoint assay, for detecting and identifying single-base variations (polymorphisms) at specific locations within DNA sequences. An oligonucleotide primer is annealed to the target DNA immediately upstream of the polymorphic site and is extended by a single base in the presence of all four dideoxynucleotide triphosphates and a thermostable DNA polymerase. The extension products are desalted, concentrated, and subjected to delayed-extraction MALDI-TOF mass spectrometry. The base at the polymorphic site is identified by the mass added onto the primer. Heterozygous targets produce two mass-resolved species that represent the addition of both bases complementary to those at the polymorphic site. The assay is suitable for double-stranded PCR products without purification or strand separation. More than one primer can be simultaneously extended and then mass-analyzed. The mass spectrometric method thus shows promise for high-volume diagnostic or genotyping applications.     

Staphylococcal culture supernates stimulate human phagocytes

c-fos induction was investigated as a potential component in the avian photic entrainment pathway and as a possible means of locating the central pacemaker in birds. In both quail (Coturnix coturnix japonica) and starlings (Sturnus vulgaris) exposure to 1 h of light induced Fos-lir in the visual suprachiasmatic nucleus but not in the medial suprachiasmatic nucleus. However, the degree of c-fos induction in the visual suprachiasmatic nucleus was similar at different circadian times despite the fact that the light pulses caused differential phase shifts in the locomotor rhythm. For golden hamsters the same experiment resulted in significantly different levels of Fos-lir in the suprachiasmatic nucleus, as well as different phase shifts. Starlings and hamsters were also entrained to T-cycles that caused a large daily phase shift (T = 21.5 h in starlings, T = 22.67 hours in hamsters), or no daily phase shift (T = free running period). No difference in the induced levels of Fos-lir in the visual suprachiasmatic nucleus region was observed between the two groups of starlings, but in hamsters there were significantly different levels of Fos-lir in the suprachiasmatic nucleus between the two groups.     

Calnexin association is not sufficient to protect T cell receptor alpha proteins from rapid degradation in CD4+CD8+ thymocytes

During T cell development, assembly of the mutisubunit T cell receptor (TCR) complex is regulated by the differential stability of newly synthesized TCRalpha molecules, having a half-life of approximately 20 min in immature CD4+CD8+ thymocytes compared with >75 min in mature T cells. The molecular basis for TCRalpha instability in CD4+CD8+ thymocytes is unknown but has been postulated to involve abnormalities in N-glycan processing and calnexin assembly as perturbation of these pathways markedly destabilizes TCRalpha proteins in all other T cell types examined. Here, we compared the processing of TCRalpha glycoproteins and their assembly with calnexin and calreticulin chaperones in CD4+CD8+ thymocytes and splenic T cells. These studies show that TCRalpha glycoproteins synthesized in CD4+CD8+ thymocytes were processed in a similar manner as those made in splenic T cells and that TCRalpha proteins stably associated with calnexin in both cell types. Interestingly, however, TCRalpha association with the calnexin-related molecule calreticulin was decreased in CD4+CD8+ thymocytes compared with splenic T cells. Finally, TCRalpha degradation in CD4+CD8+ thymocytes was impaired by inhibitors of proteasome activity, which was correlated with stabilization of calnexin.TCRalpha complexes. These data demonstrate that calnexin association is not sufficient to protect TCRalpha proteins from rapid degradation in CD4+CD8+ thymocytes, suggesting that additional components of the quality control system of the endoplasmic reticulum operate to ensure the proper folding of nascent TCRalpha glycoproteins.     

Korsakoff's syndrome, cognition and clonidine

Eighteen patients suffering from Alcoholic Korsakoff's Syndrome participated in a placebo-controlled double-blind cross-over trial of clonidine 0.3 mg b.d. for two weeks versus matched placebo for two weeks. A detailed neuropsychological assessment was carried out at the end of each treatment phase and staff ratings of behaviour were also obtained. Clonidine treatment resulted in no significant improvement over placebo on any of the cognitive measures employed. The results contradict previous smaller studies which had suggested that chronic treatment with clonidine had a memory-enhancing effect in Korsakoff's syndrome.     

Antibody coated red cells with and without hemolysis in chronic ulcerative colitis

A young female with ulcerative colitis associated with positive direct and indirect Coombs reaction and severe autoimmune hemolytic anemia is reported. Cortisone was beneficial and total colectomy was promptly followed by subsidence of the hematologic defects. Review of the literature suggests that this complication of ulcerative colitis is uncommon. It basis is unclear. It seems to be expressed through the presence of a "warm" auto-antibody. Colectomy should be strongly considered when severe hemolysis is present but not when the Coombs test is positive alone without significant hemolysis.