PubMed · 8177331
Success in controlling the AIDS epidemic is as likely to arise from unrelated areas of research as from AIDS-directed programmes.
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B N Fields. 1994-05-12. AIDS: time to turn to basic science.. https://doi.org/10.1038/369095a0
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To determine the incidence rates and to describe the epidemiological patterns of non-AIDS Kaposi's sarcoma in the central southern area of Greece during the period 1974-1989, all 473 incidence cases reported to Pathology Departments were studied. The mean age (SD) was 67.6 (12.9) years among 297 males and 66.1 (15.9) years among 176 females. The mean age-standardized (Greek population 1981) incidence rate was 0.47 cases per 100,000 total population per year (males 0.62, females 0.32). The standardized incidence rates increased over time for males, with the incidence-rate ratios relative to the earliest period, 1974-1978, being 1.44 (95% CI, 1.02-2.04) for the 1979-1983 interval and 2.12 (95% CI, 1.55-2.90) for the 1984-1989 interval. However, the rates for females did not show a similar pattern. The age-adjusted male:female ratio was 1.6 in 1974-1983 and 2.6 in 1984-1989. Poisson-regression modelling suggested a shift in the age-specific incidence rate in men, towards younger ages during the last period, 1984-1989.
The chemokine receptors CXCR4 and CCR5 function as coreceptors for HIV-1 entry into CD4+ cells. During the early stages of HIV infection, viral isolates tend to use CCR5 for viral entry, while later isolates tend to use CXCR4. The pattern of expression of these chemokine receptors on T cell subsets and their regulation has important implications for AIDS pathogenesis and lymphocyte recirculation. A mAb to CXCR4, 12G5, showed partial inhibition of chemotaxis and calcium influx induced by SDF-1, the natural ligand of CXCR4. 12G5 stained predominantly the naive, unactivated CD26(low) CD45RA+ CD45R0- T lymphocyte subset of peripheral blood lymphocytes. In contrast, a mAb specific for CCR5, 5C7, stained CD26(high) CD45RA(low) CD45R0+ T lymphocytes, a subset thought to represent previously activated/memory cells. CXCR4 expression was rapidly up-regulated on peripheral blood mononuclear cells during phytohemagglutinin stimulation and interleukin 2 priming, and responsiveness to SDF-1 increased simultaneously. CCR5 expression, however, showed only a gradual increase over 12 days of culture with interleukin 2, while T cell activation with phytohemagglutinin was ineffective. Taken together, the data suggest distinct functions for the two receptors and their ligands in the migration of lymphocyte subsets through lymphoid and nonlymphoid tissues. Furthermore, the largely reciprocal expression of CXCR4 and CCR5 among peripheral blood T cells implies distinct susceptibility of T cell subsets to viral entry by T cell line-tropic versus macrophage-tropic strains during the course of HIV infection.
Two-phase stratification sampling with unequal selection probabilities is a relatively cost-efficient strategy to address problems on a nationwide basis and to perform comparative analyses of specific subgroups. This was the case with the ACSF survey. Specific procedures to estimate the variances of unbiased estimators in complex sampling designs are not included in standard statistical packages and no specialized software is available for two-phase sampling. A detailed synthesis of general basic rules for inference about a target population from a probability sample is first presented. We follow with a standard procedure to estimate means and percentages with their confidence intervals according to the design. Finally, numerical results are discussed.