Quantification of Stachybotrys chartarum conidia in indoor dust using real time, fluorescent probe-based detection of PCR products.

Analyses of fungal spores or conidia in indoor dust samples can be useful for determining the contamination status of building interiors and in signaling instances where potentially harmful exposures of building occupants to these organisms may exist. A recently developed method for the quantification of Stachybotrys chartarum conidia, using real-time, fluorescence probe--based detection of PCR products (TaqMan system) was employed to analyze indoor dust samples for this toxigenic fungal species. Dust samples ofup to 10 mg were found to be amenable to DNA extraction and analysis. Quantitative estimates of S. chartarum conidia in composite dust samples, containing a four-log range of these cells, were within 25 -- 104% of the expected quantities in 95% of analyses performed by the method. Calibrator samples containing known numbers of S. chartarum conidia were used as standards for quantification. Conidia of an arbitrarily selected strain of Geotrichum candidum were added in equal numbers to both dust and calibrator samples before DNA extraction. Partial corrections for reductions in overall DNA yields from the dust samples compared to the calibrator samples were obtained by comparative analyses of rDNA sequence yields from these reference conidia in the two types of samples. Dust samples from two contaminated homes were determined to contain greater than 10(3) S. chartarum conidia per milligram in collection areas near the sites of contamination and greater than 10(2) conidia per milligram in several areas removed from these sites in analyses performed by the method. These measurements were within the predicted range of agreement with results obtained by direct microscopic enumeration of presumptive Stachybotrys conidia in the same samples.

Immunologic responses associated with 12 weeks of combination antiretroviral therapy consisting of zidovudine, lamivudine, and ritonavir: results of AIDS Clinical Trials Group Protocol 315.

Human immunodeficiency virus (HIV)-1 infection is associated with progressive cell-mediated immune deficiency and abnormal immune activation. Although highly active antiretroviral therapy regimens can increase circulating CD4 T lymphocyte counts and decrease the risk of opportunistic complications, the effects of these treatments on immune reconstitution are not well understood. In 44 persons with moderately advanced HIV-1 infection, after 12 weeks of treatment with zidovudine, lamivudine, and ritonavir, plasma HIV-1 RNA fell a median of 2.3 logs (P < .0001). Circulating numbers of naive and memory CD4 T lymphocytes (P < .001), naive CD8 T lymphocytes (P < .004), and B lymphocytes (P < .001) increased. Improved lymphocyte proliferation to certain antigens and a tendency to improvement in delayed-type hypersensitivity also were seen. Dysregulated immune activation was partially corrected by this regimen; however, the perturbed expression of T cell receptor V regions in the CD4 and CD8 T lymphocyte populations was not significantly affected. Ongoing studies will ascertain if longer durations of virus suppression will permit more complete immune restoration.