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This paper reports the results of mercury contamination monitoring in the Cecina river basin (Tuscany, Italy). Mercury was measured in the waters, sediments and fish species of the river and its most important tributaries. In fish specimens the organic form was also determined. The results showed high mercury levels in most of the samples analysed. Particularly high concentrations were found in the sediments of the S. Marta canal flowing into the Cecina, where a chlor-alkali plant discharges its wastes, and high levels were still detectable 31 km downstream from the confluence. Near the S. Marta confluence many fish specimens were very contaminated and a study on Leuciscus cephalus cabeda growth suggested that at this site mercury accumulation occurs in these organisms since they are very young.

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BACKGROUND: Specific information about determinants of sexual behaviour of HIV infected heterosexuals, like injecting drug use (IDU), are essential to design interventions aimed at promoting safer sex practices. METHODS: We analysed data on sexual behaviour collected, between March 1997 and March 1999, through a self administered questionnaire among 1050 IDUs and 642 non-IDU heterosexuals enrolled in a prospective multicentre cohort study on the natural history of HIV infection. RESULTS: Among non-IDU heterosexuals, more women (48.5%) than men (25.1%) (p<0.001) reported that they were infected by HIV positive regular partners whose HIV status they were not aware of. Among the 1119 heterosexual males, one fifth reported having had more than 25 sexual partners during their lifetime. Condom use in the last sexual intercourse was more common among heterosexual IDUs (64.9%) than among non-IDU heterosexual males (58.3%) (p=0.05). Heterosexual IDU males were more likely (66.7%) than non-IDU heterosexuals (50.6%) to have an HIV negative partner (p<0.001). Of the 573 heterosexual females studied, 10.2% reported having had more than 25 lifetime sex partners. This proportion was higher among heterosexual IDUs (18.8%) than among non-IDU heterosexuals (4.3%) (p<0.001). Nearly 50% of the women in both groups reported having used a condom in the last intercourse. Almost 57% of heterosexual IDUs had a current HIV negative partner, compared with 34.9% non-IDU heterosexuals (p<0.001). In both sexes, the findings from univariate analysis were confirmed by multiple logistic regression analysis. CONCLUSIONS: This study identified some important differences, in both males and females, in sexual lifestyles according to injecting drug use (for example, in terms of HIV negative partners). This observation indicates the need to tailor HIV prevention messages according to history of injecting drug use.

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BACKGROUND: It is still unclear whether the immunologic perturbation observed in women with endometriosis represents an intrinsic defect of the immune system or it is consequent to the presence of endometrium in ectopic sites. The present study was aimed to evaluate the immunoregulatory properties of ectopic endometrial implants in a model of experimental endometriosis in mice. METHODS: Endometriosis was induced in n=10 mice by inoculating endometrial fragments obtained from syngenic donor mice into the peritoneal space. Twelve mice were similarly treated but were not inoculated with endometrium and were used as control mice. At an explorative laparotomy performed in all the animals after three weeks, the extent of peritoneal lesions, when present, was evaluated by weight assessment and surface area measurement. In both mice that were inoculated with endometrium and control animals, spleens were removed. The effect of endometriosis induction on concanavalin A-induced spleenocyte proliferation was investigated. RESULTS: A significant inhibition of spleenocyte growth was demonstrated in mice in which endometriosis was induced (36156+/-3061 cpm) compared to control animals (47172+/-3210 cpm; p<0.05). Moreover, a significant inverse correlation was found between spleenocyte proliferation and weight and surface area of the peritoneal endometriotic lesions (r=0.76; p<0.02 and r=0.75; p<0.02, respectively). CONCLUSION: These findings suggest that the presence of ectopic endometrial implants within the peritoneal cavity leads to substantial changes of the immune response in vivo. These changes may have significant implications for the understanding of the etiopathogenesis of endometriosis.

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The aim of the present pilot study was to compare the efficacy and safety of trimethoprim (TMP) and sulfamethoxazole (SMX) with those of the standard therapy pyrimethamine (P)-sulfadiazine (S) for the treatment of toxoplasmic encephalitis in patients with AIDS. This was a pilot, multicenter, randomized, and prospective study. Patients were randomly assigned to receive TMP (10 mg/kg of body weight/day) and SMX (50 mg/kg/day) or P (50 mg daily) and S (60 mg/kg/day) as acute therapy (for 4 weeks) and then as maintenance therapy for 3 months at half of the original dosage. Seventy-seven patients were enrolled and randomized to the study: 40 patients were treated with TMP-SMX and 37 were treated with P-S. There was no statistically significant difference in clinical efficacy during acute therapy. In contrast, patients randomized to TMP-SMX appeared more likely to achieve a complete radiologic response after acute therapy. Adverse reactions were significantly more frequent in patients treated with P-S, and skin rash was the most common adverse event noted in these patients. In conclusion, the results of the study suggest that TMP-SMX appears to be a valuable alternative to P-S, in particular in patients with opportunistic bacterial infections.

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In this multicenter study (ISS 902), 554 previously untreated patients with <500 CD4 cells/mm3 and mildly symptomatic human immunodeficiency virus disease were randomized to receive zidovudine or didanosine (ddI). After a mean follow-up of 20 months, 80 patients (40 zidovudine, 40 ddI) had died and 146 had at least one AIDS-defining event (73 zidovudine, 73 ddI). Overall, no difference was found between treatments with respect to progression to AIDS or death. The analysis of relative risk (RR) of progression over time, however, showed an initially minor risk for zidovudine patients and an inversion in the zidovudine-ddI RR in the second and third years of follow-up. Didanosine showed a greater effect on CD4 cell count response. The two drugs confirmed the toxicity patterns already reported in other trials, with a low occurrence of pancreatitis (ddI 1.3%, zidovudine 0.4%). The overall results suggest that, in this population, zidovudine and ddI monotherapies have comparable long-term clinical efficacy and that more powerful regimens should be preferred.

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Cyclospora is recently described new human pathogenic coccidian causing intermittent diarrhoeal enteritis which may persist for weeks or months in immunocompetent subjects, particularly travellers visiting some tropical areas and countries, such as Nepal, the Caribbean, Peru and Mexico. More rarely this enteric pathogen affects immunocompromised humans, namely HIV-infected people or AIDS patients, with some clinical pictures recognized in normal hosts. We describe the first case of Cyclospora sp. and Cryptosporidium parvum associated diarrhoeal enteritis in an adult AIDS patient.

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The presence of human immunodeficiency virus type 1 (HIV-1) proviral DNA in peripheral blood mononuclear cells (PBMC) of three groups (group 1, more than 500 CD4+ T cells per microliter; group 2, between 200 and 499 CD4+ T cells per microliter; group 3, fewer than 200 CD4+ T cells per microliter) of HIV-1-infected patients, in different stages of the disease, was determined by using a newly developed flow cytometry analysis of the product of in situ PCR assay and compared with other markers of viral replication (HIV-1 p24 antigenemia and viral isolation). Results showed varied percentages of HIV-1-infected PBMC, ranging from 0.6 to 20%. Patients with more than 500 CD4+ T cells per microliter showed the lowest percentage of HIV-1-infected PBMC (2.1 +/- 1.7), compared with patients with CD4+ T-cell counts of between 200 and 499 per microliter (6.5% +/- 4.1%; P < 0.001) and patients with fewer than 200 CD4+ T cells per microliter (4.9% +/- 4.7%; P < 0.05). The difference in the percentage of HIV-1-infected PBMC between group 2 and group 3 patients may in part reflect the loss of CD4+ T lymphocytes in more advanced stages of the disease. However, the results clearly indicate a striking coincidence between the fall of the CD4+ T-cell count below 400/microliter and the sharp increase in PBMC virus loading and p24 antigenemia. Since the procedure is relatively easy to perform, it could be used to monitor the evolution of HIV-1 infection and may prove a useful adjunct in tailoring therapeutic strategies.

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OBJECTIVE: To determine the mechanism underlying the poor growth in vitro of haematopoietic progenitor cells isolated from HIV-1-infected patients. METHOD: Apoptotic death in liquid culture of bone-marrow CD34+ cells obtained from 11 HIV-1-seropositive patients and 18 HIV-1-seronegative donors was quantitatively monitored by a flow cytometry procedure. RESULTS: No significant differences in the percentage of apoptotic cells were noted between the two groups immediately after purification. When CD34+ cells were placed in liquid cultures supplemented with 2 ng/ml interleukin-3, the number of apoptotic cells progressively and significantly (P < 0.05) increased in all HIV-1-seropositive patients, while it remained constant in HIV-1-seronegative individuals. Although all HIV-1-seropositive patients showed signs of active viral replication in the bone-marrow micro-environment, progenitor CD34+ cells did not show the presence of active and/or latent HIV-1 infection. CONCLUSION: Our data demonstrate that CD34+ cells isolated from AIDS patients with active HIV-1 replication in bone-marrow accessory cells are committed to apoptotic death without being directly affected by productive infection.

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In this paper we investigated the role played by human immunodeficiency virus type 1 (HIV-1) in the pathogenesis of peripheral blood (PB) cytopenias of AIDS patients. The in vitro growth of PB granulocyte/macrophage progenitors (CFU-GM) was investigated in 45 HIV-1 seropositive (+) individuals at different stages of the disease. The number of circulating CFU-GM was significantly (p < 0.01) lower in AIDS patients (stages WR V-VI) than in HIV-1(+) asymptomatic individuals (stages WR I-II). Moreover, the presence of gag p 24 in the plasma and/or viral isolation from PB mononuclear cells of HIV-1(+) individuals was inversely correlated (p < 0.01) with the number of circulating CFU-GM, irrespectively with the stage of the disease. Viral isolates obtained from one asymptomatic and four symptomatic HIV-1(+) individuals were tested on the in vitro growth of normal hematopoietic progenitor (CD34+) cells, purified from PB of healthy donors. All the different viral isolates showed a dose-dependent inhibition of CD34+ cells, in the absence of either productive or latent infection. This suppressive effect was completely reversed by preincubating the different viral isolates with a polyclonal anti-gp 120 antibody before adding to normal CD34+ cells. These findings suggest a direct involvement of active viral replication products in the progressive impairment of hematopoiesis, characteristic of HIV-1(+) individuals in spite of the lack of a productive or latent infection of CD34+ hematopoietic progenitors.

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In this study we evaluated interleukin-6 (IL-6) plasma levels in 80 human immunodeficiency virus type 1 (HIV-1) seropositive (+) individuals and 51 HIV-1 seronegative (-) blood donors. Plasma IL-6, detectable only in a subset of HIV-1(+) individuals (45 of 80) and normal blood donors (28 of 51), was significantly (p less than 0.01) increased in HIV-1(+) subjects 187 +/- 20.5 vs. 86.3 +/- 14 pg/ml). Among HIV-1-infected individuals, ARC/AIDS patients showed the highest IL-6 values (243.3 +/- 43.3 pg/ml). HIV-1(+) subjects showed, at all the different stages of the disease, a significant increase in total gammaglobulins, particularly IgG (2071 +/- 101 vs 1265 +/- 34 of HIV-1 seronegative controls). Although among HIV-1-infected individuals, the group with detectable plasma levels of IL-6 shows the highest levels of IgG (2243 +/- 146 vs. 1790 +/- 105, p less than 0.05), no positive correlations were observed between plasma levels of IL-6 and total gamma globulins (r = 0.2) or IgG (0.17). IL-6 production was also examined in the endotoxin-free supernatants of peripheral blood cultured monocytes and CD4+ T lymphocytes, in the presence or absence of specific stimuli. The amount of IL-6 released in monocyte and CD4+ T-lymphocyte culture supernatants was similar in 40 HIV-1(+) individuals and 35 HIV-1(-) controls. Our data show that plasma levels of IL-6 are significantly increased in HIV-1-infected individuals, in particular in ARC/AIDS patients. However, such an increase does not strictly correlate with the degree of hypergammaglobulinemia in the same HIV-1-infected individuals.

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The production of granulocyte/macrophage-colony stimulating factor (GM-CSF), interleukin-1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF-alpha) were evaluated in the supernatants of short-term cultures of purified CD4+ T-lymphocytes and enriched monocytes obtained from peripheral blood (PB) of 35 HIV-1 seropositive (+) asymptomatic individuals, stages I-II of the Walter Reed (WR) classification, 15 HIV (+) symptomatic patients (WR V-VI) and 40 HIV-1 seronegative normal blood donors. IL-1 beta and TNF-alpha production by either enriched monocytes or isolated CD4+ T-cells, was similar in HIV-1 (+) asymptomatic, symptomatic subjects and normal controls. GM-CSF level in enriched monocyte culture supernatants did not show any significant difference in the three groups of subjects under investigation. On the other hand, GM-CSF production by isolated CD4+ T-lymphocytes was two-fold decreased in HIV-1 (+) asymptomatic subjects and five-fold decreased in HIV-1 (+) symptomatic patients with respect to normal blood donors. The decline in GM-CSF production was clearly correlated with viral isolation from patient's PB light density mononuclear cells (r = -0.920, p less than 0.01). The selective and progressive decline in GM-CSF production by CD4+ T-lymphocytes, starting from early stages of HIV-1 infection, suggest a preferential lesion of a specific subset of CD4+ T-lymphocytes characterized by an intense production of GM-CSF and may contribute to explain the deranged inflammatory and immune responses which characterize the course of HIV-1 infection.

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The amounts of interleukin 3 (IL-3), interleukin 4 (IL-4), tumor necrosis factor alpha (TNF-alpha), and tumor necrosis factor beta (TNF-beta) were evaluated by immunoenzymatic assays in the supernatant of short-term cultures of whole mononuclear cells and purified CD4+ T-lymphocytes, obtained from the peripheral blood (PB) of 35 HIV-1(+) asymptomatic individuals (stages I-II of the Walter Reed Classification), 20 HIV-1(+) symptomatic patients (WR V-VI), and 40 HIV-1(-) blood donors. TNF-alpha and TNF-beta production was similar in HIV-1(+) asymptomatic individuals, HIV-1(+) symptomatic patients, and HIV-1(-) controls. On the other hand, IL-3 and IL-4 production by either whole mononuclear cells or isolated CD4+ T-cells was decreased approximately 2-fold (p < 0.01) in HIV-1(+) asymptomatic subjects with respect to HIV-1(-) blood donors and was very low or almost absent in HIV-1(+) symptomatic individuals. The reduced IL-3 and IL-4 production in HIV-1-infected subjects correlated not only with the stage of the disease, but also with signs of active viral replication in PB cells, monitored by gag p24 antigen in plasma and viral isolation from PB mononuclear cells. This selective and progressive impairment in IL-3 and IL-4 production by CD4+ T-lymphocytes of HIV-1-infected subjects may contribute to explain the hematopoietic abnormalities and the derangement of the inflammatory/immune system characteristic of AIDS.

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The production of granulocyte/macrophage colony-stimulating factor (GM-CSF) by peripheral blood (PB) light density mononuclear cells (LD-MNC), CD2+ T lymphocytes and purified CD4+ T lymphocytes was investigated in 20 human immunodeficiency virus type 1 (HIV-1) seropositive (WRII-III) individuals in comparison with 18 normal controls. GM-CSF in supernatants of stimulated cultures was determined by biological and immunoenzymatic assays. GM-CSF production by LD-MNC, CD2+ T lymphocytes and purified CD4+ T lymphocytes was significantly (p less than 0.01) reduced in HIV-1 infected individuals, especially in patients at the more advanced stages of the disease. Moreover, the number of circulating granulocyte/macrophage colony-forming units (CFU-gm) was significantly (p less than 0.01) reduced in HIV-1 seropositive subjects (31.5 +/- 4.4) compared with normal controls (78 +/- 10). There was a positive correlation (r = 0.720, p less than 0.01) between CFU-gm and GM-CSF production by LD-MNC in HIV-1 seropositive individuals. On the other hand, the absolute number of CD4+ lymphocytes did not correlate with GM-CSF production by LD-MNC (r = 0.158) or CD2+ T lymphocytes (r = 0.225). These data indicate that the impaired production of GM-CSF in HIV-1-infected individuals is not only due to a reduction in CD4+ T lymphocytes, but also to a qualitative impairment of these cells which may contribute to the loss of circulating hematopoietic progenitors in HIV-1-infected subjects.

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The effect of HIV-1 on the in vitro growth of enriched hematopoietic stem cells (CD34+ cells) obtained from normal peripheral blood samples was studied. In comparison to untreated controls, the number of viable CD34+ cells progressively and significantly decreased in liquid cultures containing interleukin-3 (IL-3, 100 U/ml) after inoculation with HIV-1. In inoculated samples there was a significant reduction of all the hematopoietic progenitors (CFU-GM, BFU-E, CFU-Meg) starting from the second day of culture, CFU-GM being the most affected. In spite of these findings, no evidence of viral replication was observed: the total amount of p24 in HIV-1-inoculated CD34+ cell cultures showed a plateau, slightly declining towards the end of the experimental observation period. Moreover, erythroid and granulomacrophage colonies harvested from inoculated CD34+ cell cultures were unable to infect susceptible cells.

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To explore the mechanisms underlying liver-directed autoimmune reactions in acute Hepatitis B Virus (HBV) infection, we followed five subjects who were identified in the early incubation phase (30-70 days before the first elevation of transaminases). We assessed serially cellular (using a T-lymphocyte migration inhibitory factor assay) and humoral (RIA) immunity to LSP (a macromolecular, liver-derived lipoprotein complex) and hepatic lectin (HL), the liver-specific receptor for desialylated glycoproteins, which appears to be a major target antigen for autoreactions in autoimmune chronic active hepatitis. Anti-LSP and anti-HL autoantibodies were found, at some stage during acute HBV infection, in 4/5 subjects, whereas cellular immunity to the same antigens was detected in only two patients. Sustained production of anti-HL antibodies was noted only in patients showing cellular immunity to this antigen and was apparently secondary to liver damage, whereas anti-LSP antibodies were first detected at the onset of liver injury when there was no evidence of T-cell immunity to the same antigenic complex. One explanation for this apparent dichotomy between cellular and humoral responses to LSP is that a helper T-cell response to the major envelope component of HBV, HBsAg, which precedes by 10-20 days the development of anti-LSP antibodies, promotes a humoral reaction to autoantigens contained in the LSP preparation, coexpressed with HBsAg, on the surface of infected hepatocytes.

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To determine the time sequence of expression of pre-S2 peptide (120-150) during the presymptomatic phase of acute hepatitis B, we used a monoclonal antibody radioimmunoassay in five subjects followed from 30 to 70 days before the onset of liver damage. Pre-S2 peptide was present in serum at low levels from the early incubation phase and started to increase immediately after the first detection of HBV-DNA in serum, in parallel with the increase in HBsAg levels. During the symptomatic phase, levels of pre-S2 peptide declined rapidly; it was no longer detectable after recovery. Anti-pre-S2 antibodies were detected, in four patients, only in the recovery phase. These results demonstrate that expression of pre-S2 peptide occurs very early in the incubation phase of acute HBV infection and is cleared in parallel with HBsAg. Anti-pre-S2 antibodies seem to play no role in viral clearance in these patients.

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As part of an investigation into the question of whether virus-induced autoreactivity might contribute to liver damage in viral hepatitis, serial studies (from onset through recovery) of circulating liver autoantibodies have been performed in patients with uncomplicated acute virus A (AVH-A), B (AVH-B) and non-A, non-B (AVH-NANB) hepatitis in whom the time of onset of symptoms could be precisely documented. One hundred and forty-four sera from 35 patients were tested by radioimmunoassay for autoantibodies against the liver-derived lipoprotein complex, LSP, and also against one of its constituents--the asialoglycoprotein receptor, known as hepatic lectin (HL). Anti-LSP antibodies were found in all 10 patients with AVH-A, in 17/18 with AVH-B and in 3/7 with AVH-NANB at titres that declined during recovery. Anti-HL antibodies were detected concurrently in 6 of the AVH-A patients and in 5 with AVH-B but on only 1 occasion in 1 patient with AVH-NANB. Transient cellular immunity to LSP, assayed by a T-lymphocyte migration inhibitory factor test, was detected in 4 of the 6 AVH-B patients tested, 2 of whom also showed concurrent reactivity to HL, but these cellular immune responses did not correlate with production of anti-LSP and/or anti-HL. The findings indicate that humoral immune responses to liver cell surface antigens are frequently triggered by hepatitis A and B viruses, possibly via induction of autoreactive, T-cell independent, liver antigen-specific B lymphocytes. These liver-specific autoreactions have the potential to contribute to hepatocellular damage in virus A and B hepatitis but it seems unlikely that autoimmunity plays a significant pathogenetic role in NANB viral infections.

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Cellular immunity to hepatitis-B-virus (HBV) antigens was followed prospectively in five patients who were identified in the early incubation phase of acute HBV infection, between 30 and 70 days before the onset of liver damage. Cellular immunity to pre-S antigens was the first detectable immune response, appearing 30 days before the first rise in serum aminotransferases in every case. T-cell sensitisation to HBcAg followed, with IgM anti-HBc appearing 10 days later. A cellular immune response to HBsAg was the last to appear, 10 days before the onset of liver damage. These cellular immune responses are the earliest host responses to the virus infection and could be critical in initiating and directing the processes of liver damage and viral clearance.

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