The technology for hybridization of nucleic acids using isotopically labeled whole genomic or species‐specific cloned deoxyribonucleic acid (DNA) probes for Actinobacillus actinomycetemcomitans, Bacteroides intermedius and Bacleroides gingivulis can be used to detect as few as 102 cells of these periodontal pathogens. The sensitivity and specificity of the test is not affected by the presence of 5x 10s unrelated bacteria in constructed mixed culture samples. Current feasibility tests with non‐isotopic reagents also give reliable and rapid detection of these oral pathogens in pure or mixed cultures. DNA probes should prove useful in a rapid, specific, and sensitive assay for these periodontal pathogens.

No abstract

Malignant catarrhal fever (MCF) is a herpesvirus disease syndrome of ruminants. The microscopic pathology of MCF is characterized by lymphoid proliferation and infiltration, necrotizing vasculitis and epithelial necrosis. Because previous attempts to detect viral antigen or nucleic acids in lesions have been unsuccessful, the pathogenesis of the lesions in acute MCF has been speculated to involve mechanisms of autoimmunity and lymphocyte dysregulation. In this study, the vascular lesions in the brains of a cow and a bison with acute MCF were evaluated by in situ PCR and immunohistochemistry. The results demonstrated that the predominant infiltrating cell type in these lesions was CD8+ T lymphocytes and that large numbers of these cells were infected with ovine herpesvirus 2. The lesions also contained macrophages, but no detectable CD4 + or B lymphocytes.

In this study, we evaluated the sensitivity and specificity of whole genomic DNA probes for the periodontal pathogens Haemophilus actinomycetemcomitans, Bacteroides intermedius, and Bacteroides gingivalis. By means of these probes, DNA hybridizations were performed against other organisms found in the oral cavity and organisms previously determined to be genetically similar. All three probes were sensitive to 10(3) cells for their respective organism. The H. actinomycetemcomitans probe cross-reacted with several haemophilus strains, Wolinella, and Campylobacter, indicating that H. actinomycetemcomitans-specific sequences would have to be identified and cloned for accurate detection of this organism in heterogeneous patient samples. Only very low levels of cross-reactivity were observed between the B. intermedius probe and representative black-pigmented Bacteroides. This low level of cross-reactivity did not interfere with the accurate identification of B. intermedius in sample evaluations. The B. gingivalis probe showed no cross-reactivity. Whole genomic probes will be used for the detection of B. intermedius and B. gingivalis in patient samples.

We tested whether polymorphic membrane proteins (PMPs) of Chlamydia pneumoniae might play a role in triggering an inflammatory response in human endothelial cells. Of 15 purified, recombinant chlamydial PMPs tested, 2 (PMP 20 and PMP 21) dose-dependently increased the production of the inflammatory mediators interleukin (IL)-6 and monocyte chemoattractant protein-1 (MCP-1), in cultured human endothelial cells; production of IL-8 was also increased. When endothelial cells were infected by live C. pneumoniae, an increase in the production of IL-6, IL-8, and MCP-1 was seen. We used adenovirus-induced overexpression of IkappaBalpha-an inhibitor of nuclear factor (NF)-kappaB-to demonstrate that PMP 20 and PMP 21 increase the production of IL-6 and MCP-1 in human endothelial cells by activation of the NF-kappaB pathway, because, in cells overexpressing IkappaBalpha, treatment with the respective PMP did not result in increased production of IL-6 and MCP-1. Thus, C. pneumoniae could, by interactions of its PMPs with the endothelium, contribute to the process of vascular injury during the development and progression of atherosclerotic lesions.