Diagnostic relevance of simultaneous testing for Chlamydia trachomatis and Neisseria gonorrhoeae.

BACKGROUND: The prevalence of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infection in a Swiss cohort among individuals consulting for screening or symptomatic reasons is not very well known. METHODS: Between January 2009 and January 2010, diagnostic samples referred to us to test for either CT or NG or both were simultaneously analysed for both infections. Testing was performed using the commercial m2000sp and m2000rt devices from Abbott Diagnostics involving automated DNA extraction and semi-quantitative real-time polymerase chain reaction (PCR), respectively. RESULTS: A total of 9,245 individuals (8,009 female, 1,236 male) were tested. CT alone was found in 318 (3.97%) samples from female patients and NG infections were found in 5 (0.06%) of the female samples. Six (0.08%) women had both CT and NG infections. The numbers for males were 72 (5.83%) for CT alone, 18 (1.14%) for NG alone and 8 (0.65%) for coincident infections. Among women, a selective testing approach in which only the presence of CT was investigated missed six NG cases (0.07% prevalence, 54.55% of all NG-positive women) and the request to test only for NG missed two CT cases (0.02% prevalence, 0.62% of all CT-positive women). For the male samples, one NG case (0.08% prevalence, 3.85% of all NG-positive men) was missed when only CT was requested and three CT cases (0.24% prevalence, 3.75% of all CT-positive men) were overlooked when only NG testing was requested. CONCLUSION: A sizeable number (12) of CT and NG cases is missed by physician-referred testing for only one of the two pathogens.

Differential cytotoxic, growth-inhibiting and lipid-peroxidative activities of four different asbestos fibres in vitro.

An attempt was made to characterize the carcinogenic hazard of asbestos fibres by using a set of in vitro screening tests. The fibres tested were the serpentine chrysotile and the three amphiboles anthophyllite, crocidolite and amosite. Their cytotoxic and cytostatic activities in rat primary fibroblast-like cells were assessed along with their effects on enzymic lipid peroxidation by liver homogenates. After 24 hr exposure of fibroblast-like cells to 2.1 µg fibres/cm(2), chrysotile induced the highest cytotoxicity, followed by crocidolite, anthophyllite and amosite. Similarly, after 48 hr exposure, chrysotile had the most growth inhibiting effect, followed by crocidolite, anthophyllite and amosite. Enzymic lipid peroxidation, as measured by pentane or malondialdehyde production, was determined at ambient (21% O(2)) or tissue (4% O(2)) oxygen tension in incubation mixtures containing rat-liver homogenate and asbestos fibres. At 4% O(2), only the two iron-containing fibres, crocidolite and amosite, stimulated lipid peroxidation. The results suggest that the cytotoxic activity is influenced by the surface charge, structure and dimensions of the fibres, and that cell-growth inhibition is associated with surface charge, structure and the Mg(2+) content of the fibres. Effects on enzymic lipid peroxidation appear to be associated with the structure and iron content of the tested fibres. When these results are considered along with epidemiological data, it seems that the carcinogenic potency of asbestos fibres is characterized by an ability to induce high levels of enzymic lipid peroxidation along with moderate cytotoxic and growth inhibiting activities.

Morphological aspects of interactions between asbestos fibers and human mesothelial cell cytoskeleton.

The interaction of chrysotile and amphibole asbestos fibers with the cytoskeleton of cultured human mesothelial cells from nontumoral pleural effusions was studied using scanning electron and immunofluorescence microscopy. Asbestos-exposed mesothelial cells show a massive annular condensation of cytokeratin filaments, forming a concentric ring enveloping the nucleus and the phagocytosed asbestos fibers. By detergent extraction of the cells it could be shown that the asbestos fibers are in close contact with the nuclear membrane and associated with the cytoskeletal framework of the cells. An association of cytokeratin filaments with the asbestos could be observed during phagocytosis of the fibers. The disturbance of the cell cytoskeleton and the close morphologic contact between asbestos fibers and the nuclear membrane may have some relevance in explaining the well-recognized carcinogenic effects of asbestos mineral fibers.