HIV-1 and hepatitis B virus infections in adolescents lodged in security institutes of Buenos Aires

The goal of this study was to determine the prevalence of human immunodeficiency virus type 1 (HIV-1) and hepatitis B virus (HBV) infections in street youth lodged in security institutes, from February 1992 to March 1995, to correlate these infections with nontherapeutic drug use, and to compare these results with a previous study done in a similar population. A total of 1460 white adolescents, 276 females and 1184 males, were enrolled (mean age 16.6 years). Prevalence of HIV-1 was 4.58% and of HBV was 6.78%. The prevalence of dual HIV-1/HBV infection was 1.91%; the prevalence of HBV infection was significantly higher in HIV-positive subjects (p < 0.0000000, chi 2 = 136.17, OR = 13.37) than in those not infected with HIV-1. Prevalences were higher in males. Intravenous drug addiction proved to be a significant risk factor for both viruses (HIV-1, p < 0.0000000, chi 2 = 171.34, OR = 16.84; HBV, p = 0.000044, chi 2 = 16.67, OR = 3.17); 6.43% of the total population were intravenous drug users. Comparison of the current results with our previous study (1989-1992) showed that the prevalence of HIV-1, HBV, and concurrent HIV/HBV as well as intravenous drug addiction has decreased significantly in our current cohort (chi 2 = 134.85, p < 0.0000000; chi 2 = 126.62, p < 0.0000000; chi 2 = 110.05, p < 0.0000000; and chi 2 = 158.3, p < 0.0000000) respectively. Progress appears to have been made in the fight against acquired immunodeficiency syndrome (AIDS), and promising results have been obtained. However, if further viral spread is to be avoided, the emphasis on prevention should be energetically maintained.     

Retrospective study of children born to HIV-1-infected mothers in a pediatric hospital in Argentina

The aim of this retrospective study, which included 103 children born to human immunodeficiency virus type 1 (HIV-1)- infected mothers, is to initiate a database on HIV-infected children, which has to date been unavailable in Argentina. All HIV-1 seropositive children admitted to the Pedro de Elizalde Children's Hospital in Buenos Aires from March 1, 1987, to December 31, 1992, were enrolled in this study. The number of patients enrolled dramatically increased each year during the period of study. Of the 60 infected children, 22 (36.66%) have died with a clinical diagnosis of HIV-1 infection; in 10 of those children HIV infection was also confirmed by P24 antigenemia and/or polymerase chain reaction (PCR): 20 qualified for the Centers for Disease Control and Prevention (CDC) P2D class (P2D1 = 7, P2D2 = 10, P2D3 = 3), 1 for P2C, and 1 for P2A, whose cause of death was pneumonia. The mean age of death was 14.8 months, 18 (82%) died before 18 months. When immunoglobulin G (IgG), IgM, and IgA levels were determined according to age and clinical status, significant differences (P < 0.005) were observed when both asymptomatic and symptomatic infected children (P1, P2) were compared with noninfected children (P3). A significant difference was also obtained between those children who qualified for P2 classification prior to 12 months of age who died early (at or prior to 25 months) and those who reached stage P2 after 12 months of age and have survived to date (X2 = 24.73, p < 0.0001; RR = 5.83, 2.52 < RR < 13.49).     

Humoral response to Mycobacterium tuberculosis in patients with human immunodeficiency virus infection.

The effect of the human immunodeficiency virus (HIV) on mycobacterial antibody production was investigated. Using an enzyme-linked immunosorbent assay (ELISA) for detecting IgG against Mycobacterium tuberculosis PPD, it was observed that individuals at risk of HIV infection show a pattern of humoral response to the tubercle bacillus similar to that previously found in the immunocompetent population not exposed to risk factors: 6 of 12 (50.0%) tuberculosis cases had elevated levels of antibodies to PPD and 27 of 30 (90.0%) asymptomatic individuals had antibody levels within the normal range. In an HIV-seropositive group without AIDS indicator diseases, 8 of 22 (36.4%) tuberculous patients had detectable mycobacterial antibodies whereas 156 of 164 (95.1%) non-tuberculous subjects did not. Among AIDS cases, only 1 of 20 (5.0%) patients with tuberculosis and none of 53 non-tuberculous subjects showed a positive result. The study evidenced an increasing humoral unresponsiveness to PPD in the progression of HIV infection to AIDS. Thus, a serodiagnostic method for detecting tuberculosis such as the ELISA here employed noticeably decreases its utility in the latency stage of the HIV infection, and it is practically useless in clinical AIDS.     

Identification of human immunodeficiency virus type 1 subtypes B and F B/F recombinant and dual infection with these subtypes in Argentina.

DNA sequences encoding the third variable region (V3) of human immunodeficiency virus type-1 (HIV-1) envelope glycoprotein gp120 were obtained from 18 infected individuals residing in different regions of Argentina. Proviral DNA representing the env V3 region was obtained by PCR from uncultured peripheral blood mononuclear cells (PBMC) and genetic heterogeneity was examined by phylogenetic analysis. Sequences representing the gag p17 region were also obtained for a subset of these samples. Moreover, 1 sample that it was not possible to classify according to initial phylogenetic analysis was further analysed by molecular cloning of both V3 and p17 regions. Phylogenetic analysis according to different methodologies were performed comparing obtained sequences with a set of reference sequences representing previously characterized HIV-1 subtypes. The recombinant identification program (RIP) was used to study the presence of possible recombinant sequences. Phylogenetic analysis demonstrated that viruses representing both subtypes B and F are circulating among HIV-1 infected individuals in Argentina. In addition, RIP analysis showed that an initially unclassified sequence exhibited similarities to subtypes B and F in different fragments of the V3 region. Separate phylogenetic analysis of each of these fragments revealed divergent clustering, suggesting that this sequence harbours a point of recombination within the V3 loop. Interestingly, we also identified a dually infected individual with viruses belonging to subtypes B and F, as demonstrated by molecular cloning analysis of the env V3 and the gag p17 regions. Taken together, our study shows that both subtypes B and F are circulating in different regions of Argentina. Moreover, the data presented here show that dual infections with subtypes B and F can occur, and consequently B/F recombinant sequences are arising in the region.     

Dietary polyamines promote the growth of azoxymethane-induced aberrant crypt foci in rat colon

We have examined whether dietary polyamines influence the formation and initial growth of azoxymethane (AOM)-induced aberrant crypt foci (ACF) in rat colon. Effects of a combination of dietary polyamines at three dose levels (putrescine: 50, 280, 740 nmol/g; spermidine: 10, 261, 763 nmol/g; spermine: 1, 31, 91 nmol/g) in the polyamine-poor AIN-76A diet were studied in animals in two different experimental situations: animals treated with AOM alone and animals treated with AOM + difluoromethylornithine (DFMO), a specific inhibitor of endogenous polyamine synthesis. In both experimental situations, dietary polyamines enhanced the growth of ACF, expressed as the number of large ACF (foci with three or more aberrant crypts, ACF > or = 3), whereas the formation of ACF, expressed as the number of ACF, was apparently not altered. In animals treated with AOM alone, maximal growth enhancing effect on ACF was nearly obtained with the median level of dietary polyamine. In rats fed a low polyamine diet, basic AIN-76A, DFMO reduced the growth of AOM-induced ACF by 83%. This inhibitory effect of DFMO was counteracted by dietary polyamines in a dose- dependent manner, and it was abolished at the highest level of polyamines. In conclusion, it was demonstrated that dietary polyamines are able to enhance the growth of AOM-induced ACF. Further, dietary polyamines reversed the DFMO-caused inhibition of ACF growth, probably by compensating for the DFMO-reduced endogenous polyamine synthesis.      

Maternal antibodies to HIV-1 envelope domains: No correlation with HIV-1 vertical transmission in patients from Argentina

The role of the maternal antibody response in relation to vertical human immunodeficiency virus type 1 (HIV-1) transmission was investigated in HIV-1-infected mothers from Argentina. Sera from 23 transmitting and 18 nontransmitting HIV-1-infected mothers were tested for the presence of antibodies to V3 loop gp120 peptides representing both Argentinian sequences and several well-characterized viral isolates from different geographic areas. Argentinian sera from transmitting mothers had significantly higher capacity to react with four of 14 V3 loop peptides tested than sera from nontransmitting mothers. Frequency of reactivity against the other peptides did not differ between the two maternal groups. Furthermore, no differences in antibody affinity were found between transmitting and nontransmitting mothers. Sera were also tested against overlapping peptides covering a neutralizing epitope of the HIV-1 MN gp41 (amino acids 648-677). Statistical analysis indicated that no correlation between anti-gp41 antibodies and vertical transmission exists. Although we used V3 loop peptides based on local HIV-1 sequences, our data showed that maternal antibodies to these peptides, as well as to gp41 peptides, are not correlated with protection against HIV-1 vertical transmission.     

Evasin‐3‐like anti‐chemokine activity in salivary gland extracts of ixodid ticks during blood‐feeding: a new target for tick control

Ticks exploit many evasion mechanisms to circumvent the immune control of their hosts including subversion of the communication language between cells of the immune system provided by chemokines and other cytokines. One subversive molecule secreted in the saliva of Rhipicephalus sanguineus is Evasin‐3, a structurally unique 7 kDa protein that selectively binds the neutrophil chemoattractants, CXCL8 and (with lower affinity) CXCL1. We compared anti‐human CXCL8 and anti‐mouse CXCL1/KC activities in salivary gland extracts prepared from adult Amblyomma variegatum, Rhipicephalus appendiculatus and Dermacentor reticulatus ticks during blood‐feeding. Both anti‐CXCL8 activity and anti‐CXCL1 activity were detected in all species and in both adult females and males, with consistently higher activity levels against CXCL8. These results suggest that Evasin‐3‐like activity is common amongst metastriate ixodid tick species, and provide further evidence of the importance to ticks in controlling neutrophils during blood‐feeding. As such, Evasin‐3 offers a new target for anti‐tick vaccine development.