Clinical and immunological aspects of HIV infection in drug addicts
ABSTRACT Intravenous drug users (IVDUs) account for more than 64% of the total AIDS cases in Italy. The IVDUs' seropositivity rate is >70% in Milan and >50% in the main cities of Italy. The first evidence of seropositivity in this population dates back to 1979. In a cohort study performed in Milan the rate of progression to overt AIDS among IVDUs was 6% in 3 years (1984–1987). At presentation, more than 75% of the subjects had CD4+ cell counts higher than 400/mm3 (mean 631, median 528, mode 465). These values are significantly higher than those observed in the same population in New York, the only American city with HIV-infection spread comparable to that observed in Milan. The probability of having CD4+ cell counts lower than 400, 300, and 200/mm3 in relation to the length of follow-up was, respectively, 50, 40, and 2% after 36 months from presentation. At the same end point, subjects presenting less than 400 CD4+ cells at entry had 30% probability of falling under 200 cell/mm3. The pattern of CD4+ cells, as much as the low percentage of yearly progression to overt AIDS, is probably related to the recent, even if rapid, spread of infection among IVDUs in Italy. The clinical features of overt AIDS present some differences between IVDUs and other at-risk groups. Among U.S. IVDUs with AIDS, Kaposi's sarcoma is infrequent (2.9% vs 27.7% in homosexual men) while mycotic infections such as deep candidiasis and cryptococcosis are significantly more frequent. The same pattern has been observed in our case file in Milan: esophageal candidiasis represents the most frequent cause of diagnosis of overt AIDS. Mycotic infections, overall, are more frequent than in U.S. IVDUs. The increased rate of mycotic infections among IVDUs might be justified by altered functions of nonspecific immunity, such as PMNL killing and phagocytosis of Candida albicans spores, impaired in HIV-infected IVDUs, but generally normal in infected subjects belonging to the other at-risk groups.
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ABSTRACT: We analyzed the morphologic and microbiologic aspects of the process of adhesion and invasion in the early stages of Candida albicans oral infection in a murine system. ICR mice were anesthetized by intramuscular injection with chlorpromazine chloride and then orally inoculated by swabbing with the C. albicans yeast cells. Their tongues were resected 1-3h after inoculation, washed sequentially with a physiological saline and 0.25% trypsin-solution and then homogenized. The number of viable C. albicans cells on the tongue surface was counted and fround to increase from 1-3h after inoculation. Most of the Candida cells attached to the tongue surface were present in clusters, mainly located in the gaps between lingual papillae and were covered with a mucoidal substance. By 3h after inoculation, these clusters frequently formed mycelia and could not be easily detached from the tongue surface by trypsin treatment. Observation of SEM and histological sections stained by Fungiflora Y revealed that the Candida hyphae at 3h stretched out of the cluster and entered the tongues through the surface. These results indicate that Candida hyphae begin to invade the tongue surface within 3h after inoculation and suggest that the mucus-like substance covering these cells may have an important early role in the interaction between the Candida cells and the tongue mucosal epithelium.Medical Mycology 06/2008; 46(7):697-704. · 1.98 Impact Factor
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ABSTRACT: The purpose of this study was to examine gender and ethnic differences in survival of persons receiving treatment for HIV infection to determine if differences existed, and if they did, to assess the possibility of explaining these differences by examining other factors, such as age, disease severity when beginning treatment, alcohol, illicit drugs, tobacco, educational level, living arrangements, antiretroviral treatment, PCP prophylaxis, sexually transmitted diseases, mode of transmission and opportunistic infections. A retrospective cohort study of all clients receiving treatment at an HIV only clinic from its opening in early 1988 until the end of May 1993. Statistical methods used to examine the data included incidence density ratios, Kaplan-Meier survival curves, Breslow (generalized Wilcoxon) tests of equality of survival curves and Cox proportional hazards models both with and without time dependent covariates. In the cohort (37% African American, 7% Hispanic American and 25% female), 220 deaths occurred during 1223 person years of follow-up. Compared to European American males, the following incidence density ratios were observed: European American females: 0.50, Hispanic American females: 0.70, Hispanic American males: 0.96, African American females: 1.28 and African American males: 2.38. The differences were noted above for gender/ethnicity groups were significant at the p < 0.0001 level. After adjusting for disease stage (as measured by laboratory testing of CD4 positive T-lymphocytes), educational level, and age, no differences in survival by gender or ethnicity remained. Disease stage and educational level had the greatest prognostic significance. European Americans entered treatment at a much earlier disease stage (as measured by CD4 positive T-lymphocyte counts) and had higher educational levels (a surrogate for socioeconomic status) than African Americans. These factors may explain the longer survival in European Americans as compared to African Americans in this cohort.Ethnicity and Health 04/1996; 1(1):77-85. · 1.20 Impact Factor
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ABSTRACT: Oral candidiasis is as much the final outcome of the vulnerability of the host as of the virulence of the invading organism. We review here the extensive literature on animal experiments mainly appertaining to the host predisposing factors that initiate and perpetuate these infections. The monkey, rat, and mouse are the choice models for investigating oral candidiasis, but comparisons between the same or different models appear difficult, because of variables such as the study design, the number of animals used, their diet, the differences in Candida strains, and the duration of the studies. These variables notwithstanding, the following could be concluded. (i) The primate model is ideal for investigating Candida-associated denture stomatitis since both erythematous and pseudomembranous lesions have been produced in monkeys with prosthetic plates; they are, however, expensive and difficult to obtain and maintain. (ii) The rat model (both Sprague-Dawley and Wistar) is well proven for observing chronic oral candidal colonization and infection, due to the ease of breeding and handling and their ready availability. (iii) Mice are similar, but in addition there are well characterized variants simulating immunologic and genetic abnormalities (e.g., athymic, euthymic, murine-acquired immune deficiency syndrome, and severe combined immunodeficient models) and hence are used for short-term studies relating the host immune response and oral candidiasis. Nonetheless, an ideal, relatively inexpensive model representative of the human oral environment in ecological and microbiological terms is yet to be described. Until such a model is developed, researchers should pay attention to standardization of the experimental protocols described here to obtain broadly comparable and meaningful data.Clinical Microbiology Reviews 05/2001; 14(2):398-429. · 17.31 Impact Factor