Human immunodeficiency virus/acquired immunodeficiency syndrome and tropical diseases: a Brazilian perspective

The paper summarizes recent findings on the epidemiology and pathogenesis of human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/Aids), highlighting the role of co-infections with major tropical diseases. Such co-infections have been studied in the Brazilian context since the beginning of the Aids epidemic and are expected to be more frequent and relevant as the Aids epidemic in Brazil proceeds towards smaller municipalities and the countryside, where tropical diseases are endemic. Unlike opportunistic diseases that affect basically the immunocompromised host, most tropical diseases, as well as tuberculosis, are pathogenic on their own, and can affect subjects with mild or no immunossuppression. In the era of highly active anti-retroviral therapies (HAART), opportunistic diseases seem to be on decrease in Brazil, where such medicines are fully available. Benefiting from HAART in terms of restoration of the immune function, putative milder clinical courses are expected in the future for most co-infections, including tropical diseases. On the other hand, from an ecological perspective, the progressive geographic diffusion of Aids makes tropical diseases and tuberculosis a renewed challenge for Brazilian researchers and practitioners dealing with HIV/Aids in the coming years.

Oviposition response of the mosquito, Culex quinquefasciatus to the secondary metabolite(s) of the fungus, Trichoderma viride

Secondary metabolites produced by Trichoderma viride, a deuteromycetes fungus, under submerged culture condition were formulated and evaluated for oviposition attractancy against gravid females of Culex quinquefasciatus mosquito. At a concentration of 10 µg ml-1 the formulation showed remarkable attractancy with an oviposition active index (OAI) of +0.52. When the oviposition attractancy of the formulation was compared with a known oviposition attractant, p-cresol, both at 10 µg ml-1, the former was found to be more attractive to result in 70% egg laying than the later with 30% egg laying. Thin layer chromatography fractions of the secondary metabolites showed that a fraction with Rf value of 0.88 was highly active as oviposition attractant with an OAI of +0.65. Further work on identification of the active principle(s) of the microbial formulation might lead to an oviposition attractant useful in mosquito vector management.

Comparison of the epidemiology, profile of mutations, and clinical response to antiretrovirals among subtypes B and F of the human immunodeficiency virus type 1

The authors compared demographic aspects and profile of mutations in 80 patients with subtypes B and F of human immunodeficiency type 1 (HIV-1). Genotyping of the pol region of the reverse transcriptase was performed using the ViroSeqTM Genotyping System. A total of 61 (76.2%) patients had subtype B and 19 (23.8%) subtype F of the HIV-1. Subtype F tended to be more frequent in heterosexuals and women with a low educational level, but without statistical significance. The frequency of mutations related to nucleoside reverse transcriptase inhibitors and protease inhibitors (PI) was the same in the two subtypes, but mutations related to PI at the codons 63, 77, and 71 were more frequent in subtype B, while mutations at the codons 36 and 20 predominated in subtype F. Sixty-two of the 80 patients infected with subtypes B and F were submitted to antiretroviral therapy for an average of 18-22 months. Undetectable viral loads at the end of follow-up were similar in the two groups, representing 63.8% of subtype B and 73.3% of subtype F (p = 0.715). CD4 lymphocyte counts before and after treatment were similar in the two groups. This study, despite pointing to possible epidemiological and genetic differences among subtypes B and F of HIV-1, suggests that the use of highly active antiretroviral therapy is equally effective against these subtypes.

Molecular diversity of serial Cryptococcus neoformans isolates from AIDS patients in the city of São Paulo, Brazil

Despite highly active anti-retroviral therapy, cryptococcal meningoencephalitis is the second most prevalent neurological disease in Brazilian AIDS patients, being frequently a defining condition with several episodes. As knowledge of Cryptococcus neoformans isolates in the same episode is critical for understanding why some patients develop several episodes, we investigated the genotype characteristics of C. neoformans isolates in two different situations. By pulsed field gel electrophoresis and random amplifield polymorphic DNA analysis, 54 isolates from 12 patients with AIDS and cryptococcosis were analyzed. Group 1 comprised 39 isolates from nine patients with a single episode and hospitalization. Group 2 comprised 15 isolates from three patients with two episodes and hospitalizations. Except for three patients from group 1 probably infected with a single C. neoformans isolate, the other nine patients probably were infected with multiple isolates selected in different collection periods, or the infecting isolate might have underwent mutation to adapt and survive the host immune system and/or the antifungal therapy. However, the three patients from group 2 presented genetic diversity among isolates collected in both hospitalizations, possibly having hosted the initial isolate in both periods. These data, emphasize that Cryptococcus diversity in infection can contribute to strategies of treatment and prevention of cryptococcosis.

HIV-1 tropism and CD4 T lymphocyte recovery in a prospective cohort of patients initiating HAART in Ribeirão Preto, Brazil

While human immunodeficiency virus (HIV)-1 chemokine co-receptors 5 tropism and the GWGR motif in the envelope third variable region (V3 loop) have been associated with a slower disease progression, their influence on antiretroviral response remains unclear. The impact of baseline V3 characteristics on treatment response was evaluated in a randomised, double blind, prospective cohort study with patients initiating highly active antiretroviral therapy with lopinavir or efavirenz plus azithothymidine/3TC (1:1) over 48 weeks. Similar virological and immunological responses were observed for both treatment regimens. The 43 individuals had a mean baseline CD4 T cell count of 119 cells/mm³ [standard deviation (SD) = 99] and a mean viral load of 5.09 log10 copies/mL (SD = 0.49). The GWGR motif was not associated with a CD4 T cell response, but predicted R5 tropism by the geno2pheno[clinical20%] algorithm correlated with higher CD4 T cell levels at all monitoring points (p < 0.05). Moreover, higher false-positive rates (FPR) values from this analysis revealed a strong correlation with CD4 T cell recovery (p < 0.0001). Transmitted drug resistance mutations, documented in 3/41 (7.3%) cases, were unrelated to the assigned antiretroviral regimen and had no impact on patient outcomes. In conclusion, naÏve HIV-1 R5 infected patients exhibited higher CD4 T cell counts at baseline; this difference was sustained throughout therapy. The geno2pheno[clinical] option FPR positively correlated with CD4 T cell gain and may be useful in predicting CD4 T cell recovery.

Parvovirus B19 seroconversion in a cohort of human immunodeficiency virus-infected patients

Erythrovirus B19 (B19V) infection may cause red cell aplasia in patients infected with human immunodeficiency virus (HIV). The introduction of highly active antiretroviral therapy (HAART) has improved the immune function of these patients by modifying the course of B19V infection. The purpose of this study was to estimate the frequency of B19 seroconversion in a cohort of HIV-infected patients and evaluate the occurrence of B19V-related anaemia during the seroconversion period. Adult HIV-infected patients were studied at a public hospital in Niterói, state of Rio de Janeiro, Brazil. IgG and IgM antibodies against B19V were detected by an enzyme-linked immunosorbent assay and B19 viraemia was assayed by polymerase chain reaction. Medical records were reviewed for any clinical evaluation of anaemia. Seroconversion was detected in 31.8% of the 88 individuals who began the study as anti-B19V IgG-negative. No clinical manifestations of B19V infection were detected during the period of seroconversion. Patients who seroconverted were 5.40 times more likely to have anaemia than those who did not [odds ratio 5.40 (95% confidence interval: 1.33-22.93)]. Anaemia was detected in eight patients. All patients recovered from anaemia by either beginning or continuing HAART, without requiring blood transfusions. In the HAART era, B19V infection may only be associated with a course of disease characterised by less severe chronic anaemia. This milder course of B19V-associated disease is likely due to the increased immune function of HAART-treated patients.

Clinical features and laboratory findings of human parvovirus B19 in human immunodeficiency virus-infected patients

Immunocompromised patients may develop severe chronic anaemia when infected by human parvovirus B19 (B19V). However, this is not the case in human immunodeficiency virus (HIV)-infected patients with good adherence to highly active antiretroviral treatment (HAART). In this study, we investigated the clinical evolution of five HIV-infected patients receiving HAART who had B19V infections confirmed by serum polymerase chain reaction. Four of the patients were infected with genotype 1a strains and the remaining patient was infected with a genotype 3b strain. Anaemia was detected in three of the patients, but all patients recovered without requiring immunoglobulin and/or blood transfusions. In all cases, the attending physicians did not suspect the B19V infections. There was no apparent relationship between the infecting genotype and the clinical course. In the HAART era, B19V infections in HIV-positive patients may be limited, subtle or unapparent.

Megazol and its bioisostere 4H-1,2,4-triazole: comparing the trypanocidal, cytotoxic and genotoxic activities and their in vitro and in silico interactions with the Trypanosoma brucei nitroreductase enzyme

Megazol (7) is a 5-nitroimidazole that is highly active against Trypanosoma cruzi and Trypanosoma brucei, as well as drug-resistant forms of trypanosomiasis. Compound 7 is not used clinically due to its mutagenic and genotoxic properties, but has been largely used as a lead compound. Here, we compared the activity of 7 with its 4H-1,2,4-triazole bioisostere (8) in bloodstream forms of T. brucei and T. cruzi and evaluated their activation by T. brucei type I nitroreductase (TbNTR) enzyme. We also analysed the cytotoxic and genotoxic effects of these compounds in whole human blood using Comet and fluorescein diacetate/ethidium bromide assays. Although the only difference between 7 and 8 is the substitution of sulphur (in the thiadiazole in 7) for nitrogen (in the triazole in 8), the results indicated that 8 had poorer antiparasitic activity than 7 and was not genotoxic, whereas 7 presented this effect. The determination of Vmax indicated that although 8 was metabolised more rapidly than 7, it bounds to the TbNTR with better affinity, resulting in equivalent kcat/KM values. Docking assays of 7 and 8 performed within the active site of a homology model of the TbNTR indicating that 8 had greater affinity than 7.

In vitro activity of the hydroethanolic extract and biflavonoids isolated from Selaginella sellowii on Leishmania (Leishmania) amazonensis

This study is the first phytochemical investigation of Selaginella sellowii and demonstrates the antileishmanial activity of the hydroethanolic extract from this plant (SSHE), as well as of the biflavonoids amentoflavone and robustaflavone, isolated from this species. The effects of these substances were evaluated on intracellular amastigotes of Leishmania (Leishmania) amazonensis, an aetiological agent of American cutaneous leishmaniasis. SSHE was highly active against intracellular amastigotes [the half maximum inhibitory concentration (IC50) = 20.2 µg/mL]. Fractionation of the extract led to the isolation of the two bioflavonoids with the highest activity: amentoflavone, which was about 200 times more active (IC50 = 0.1 μg/mL) and less cytotoxic than SSHE (IC50 = 2.2 and 3 μg/mL, respectively on NIH/3T3 and J774.A1 cells), with a high selectivity index (SI) (22 and 30), robustaflavone, which was also active against L. amazonensis (IC50 = 2.8 µg/mL), but more cytotoxic, with IC50 = 25.5 µg/mL (SI = 9.1) on NIH/3T3 cells and IC50 = 3.1 µg/mL (SI = 1.1) on J774.A1 cells. The production of nitric oxide (NO) was lower in cells treated with amentoflavone (suggesting that NO does not contribute to the leishmanicidal mechanism in this case), while NO release was higher after treatment with robustaflavone. S. sellowii may be a potential source of biflavonoids that could provide promising compounds for the treatment of cutaneous leishmaniasis.

Computational drug design strategies applied to the modelling of human immunodeficiency virus-1 reverse transcriptase inhibitors

Reverse transcriptase (RT) is a multifunctional enzyme in the human immunodeficiency virus (HIV)-1 life cycle and represents a primary target for drug discovery efforts against HIV-1 infection. Two classes of RT inhibitors, the nucleoside RT inhibitors (NRTIs) and the nonnucleoside transcriptase inhibitors are prominently used in the highly active antiretroviral therapy in combination with other anti-HIV drugs. However, the rapid emergence of drug-resistant viral strains has limited the successful rate of the anti-HIV agents. Computational methods are a significant part of the drug design process and indispensable to study drug resistance. In this review, recent advances in computer-aided drug design for the rational design of new compounds against HIV-1 RT using methods such as molecular docking, molecular dynamics, free energy calculations, quantitative structure-activity relationships, pharmacophore modelling and absorption, distribution, metabolism, excretion and toxicity prediction are discussed. Successful applications of these methodologies are also highlighted.

Provision of health care actions and services for the management of HIV/AIDS from the users’ perspective

Objective To analyse the provision of health care actions and services for people living with AIDS and receiving specialised care in Ribeirão Preto, SP. Method A descriptive, exploratory, survey-type study that consisted of interviews with structured questionnaires and data analysis using descriptive statistics. Results The provision of health care actions and services is perceived as fair. For the 301 subjects, routine care provided by the reference team, laboratory tests and the availability of antiretroviral drugs, vaccines and condoms obtained satisfactory evaluations. The provision of tests for the prevention and diagnosis of comorbidities was assessed as fair, whereas the provisions of specialised care by other professionals, psychosocial support groups and medicines for the prevention of antiretroviral side effects were assessed as unsatisfactory. Conclusion Shortcomings were observed in follow-up and care management along with a predominantly biological, doctor-centred focus in which clinical control and access to antiretroviral therapy comprise the essential focus of the care provided.


Síntese enzimática de butirato de isoamila empregando lipases microbianas comerciais

Isoamyl butyrate production was investigated using free and immobilized lipases by esterification of butyric acid with isoamyl alcohol in a solvent-free system and in an organic media. Among the enzymes studied, Lipozyme TL IM was found to be the most active catalyst in n-hexane as a solvent. The effects of different solvents and the amount of water added on conversion rates were studied. A maximum conversion yield of 80% in n-hexano at 48 h was obtained under the following conditions: 3 g L-1 of Lipozyme TL IM, 30 ºC, 180 rpm of agitation, isoamyl alcohol to butyric acid molar ratio of 1:1 and acid substrate concentration of 0.06 M.

Low metal loading catalysts used for the selective hydrogenation of styrene

A series of Group VIII metal catalysts was obtained for the semi-hydrogenation of styrene. Catalysts were characterized by Hydrogen Chemisorption, TPR and XPS. Palladium, rhodium and platinum low metal loading prepared catalysts presented high activity and selectivity (ca. 98%) during the semi-hydrogenation of styrene, being palladium the most active catalyst. The ruthenium catalyst also presented high selectivity (ca. 98%), but the lowest activity. For the palladium catalyst, the influence of the precursor salt and of the reduction temperature on the activity and selectivity were studied. The following activity series was obtained: PdN-423 > PdCl-673 > PdCl-373> PtCl-673 > RhCl-673 >> RuCl-673. As determined by XPS, differences in activity could be attributed, at least in part, to electronic effects.

Characterization and catalytic performance of potassium loaded on rice husk silica and zeolite nay for transesterification of jatropha seed oil

Rice husk silica (RHS) and NaY were used as supports for potassium (K) prepared from acetate buffer (B) and acetate (A) solutions. K loading did not destroy the NaY structure, but it caused a decrease in the surface area; the K species resided in micropores and on the external surface. In contrast, K loading resulted in the collapse and a decrease in the surface area of RHS. It was found that 12K/NaY-B was the most active catalyst for the transesterification of Jatropha seed oil. The minimum K content in K/NaY-B that provided complete conversion of the Jatropha seed oil was 11 wt%, and the biodiesel yield was 77.9%.

Cardiovascular complications and increased levels of circulating modified low density lipoprotein in HIV patients and patients with lipodystrophy

The introduction of highly active antiretroviral therapy (HAART) for patients infected with HIV has significantly prolonged the life expectancy and to some extent has restored a functional immune response. However, the premature introduction of HAART has led to a significant and alarming increase in cardiovascular complications, including myocardial infarction and the appearance of abnormal distribution of body fat seen as lipodystrophy. One key element in the development of ischemic coronary artery disease is the presence of circulating and tissue-fixed modified low density lipoprotein (mLDL) that contributes to the initiation and progression of arterial lesions and to the formation of foam cells. Even though not completely elucidated, the most likely mechanism involves mLDL in the inflammatory response and the induction of a specific immune response against mLDL. Circulating antibodies against mLDL can serve as an indirect marker of the presence of circulating and vessel-fixed mLDL. In the present study, we measured antibodies to mLDL and correlated them with immune status (i.e., number of CD4+ T cells) in 59 HIV patients and with the clinical manifestation of lipodystrophy in 10 patients. We observed a significant reduction in anti-mLDL antibody levels related both to lipodystrophy and to an immunocompromised state in HIV patients. We speculate that these antibodies may explain in part the rapid development of ischemic coronary artery disease in some patients.