Basic biochemical investigations as rationale for the design of original antimalarial drugs. An example of phospholipid metabolism

The future of antimalarial chemotherapy is particulary alarming in view of the spread of parasite cross-resistances to drugs that are not even structurally related. Only the availability of new pharmacological models will make it possible to select molecules with novel mechanisms of action, thus delaving resistance and allowing the development of new chemotherapeutic strategies. We reached this objective in mice. Our approach is hunged on fundamental and applied research begun in 1980 to investigate to phospholipid (PL) metabolism of intraerythrocytic Plasmodium. This metabolism is abundant, specific and indispensable for the production of Plasmodium membranes. Any drug to interfere with this metabolism blocks parasitic development. The most effective interference yet found involves blockage of the choline transporter, which supplies Plasmodium with choline for the synthesis of phosphatidylcholine, its major PL, this is a limiting step in the pathway. The drug sensitivity thereshold is much lower for the parasite, which is more dependent on this metabolism than host cells. The compounds show in vitro activity against P. falciparum at 1 to 10 nM. They show a very low toxicity against a lymphblastoid cell line, demonstrating a total abscence of correlation between growth inhibition of parasites and lymphoblastoid cells. They show antimalarial activity in vivo, in the P. berghei or P. chabaudi/mouse system, at doses 20-to 100-fold lower than their in acute toxicity limit. The bioavailability of a radiolabeled form of the product seemed to be advantageous (slow blood clearance and no significant concentration in tissues). Lastly, the compounds are inexpensive to produce. They are stable and water-soluble.

Biogeography of Triatominae (Hemiptera: Reduviidae) in Ecuador: implications for the design of control strategies

Chagas disease control strategies strongly depend on the triatomine vector species involved in Trypanosoma cruzi transmission within each area. Here we report the results of the identification of specimens belonging to various species of Triatominae captured in Ecuador (15 species from 17 provinces) and deposited in the entomological collections of the Catholic University of Ecuador (Quito), Instituto Oswaldo Cruz (Brazil), the Natural History Museum London (UK), the London School of Hygiene and Tropical Medicine (UK), the National Institute of Hygiene (Quito), and the Vozandes Hospital (Quito). A critical review of published information and new field records are presented. We analysed these data in relation to the life zones where triatomines occur (11 life zones, excluding those over 2,200 m altitude), and provide biogeographical maps for each species. These records are discussed in terms of epidemiological significance and design of control strategies. Findings relevant to the control of the main vector species are emphasised. Different lines of evidence suggest that Triatoma dimidiata is not native to Ecuador-Peru, and that synanthropic populations of Rhodnius ecuadoriensis in southern Ecuador-northern Peru might be isolated from their sylvatic conspecifics. Local eradication of T. dimidiata and these R. ecuadoriensis populations might therefore be attainable. However, the presence of a wide variety of native species indicates the necessity for a strong longitudinal surveillance system.

Polymorphism of the Human Immunodeficiency Virus Type 1 in Brazil: Genetic Characterization of the nef Gene and Implications for Vaccine Design

Most of the Brazilian HIV-1 samples have been characterized based on the structural genes (env, gag and pol) and no data concerning the variability of the accessory genes such as nef have been available so far. Considering the role of the nef on virus biology and the inclusion of this region in some HIV/AIDS vaccine products under testing, the purpose of this study was to document the genetic diversity of the nef gene in third-four HIV-1 Brazilian samples previously subtyped based on the env C2-V3 region. Although only few non-subtype B samples have already been analyzed so far, the cytotoxic Tlymphocyte epitopes encoded in this region were relatively conserved among the subtypes, with some amino acid signatures mainly in the subtype C samples. Considering the increasing of the non-B HIV-1 subtypes worldwide, in special the subtype C, more data should be generated concerning the genetic and antigenic variability of these subtypes, as well as the study of the impact of such polymorphism in HIV/AIDS vaccine design and testing.

Mapping the molecular characteristics of Brazilian human T-cell lymphotropic virus type 1 Env (gp46) and Pol amino acid sequences for vaccine design

This study was carried out to evaluate the molecular pattern of all available Brazilian human T-cell lymphotropic virus type 1 Env (n = 15) and Pol (n = 43) nucleotide sequences via epitope prediction, physico-chemical analysis, and protein potential sites identification, giving support to the Brazilian AIDS vaccine program. In 12 previously described peptides of the Env sequences we found 12 epitopes, while in 4 peptides of the Pol sequences we found 4 epitopes. The total variation on the amino acid composition was 9 and 17% for human leukocyte antigen (HLA) class I and class II Env epitopes, respectively. After analyzing the Pol sequences, results revealed a total amino acid variation of 0.75% for HLA-I and HLA-II epitopes. In 5 of the 12 Env epitopes the physico-chemical analysis demonstrated that the mutations magnified the antigenicity profile. The potential protein domain analysis of Env sequences showed the loss of a CK-2 phosphorylation site caused by D197N mutation in one epitope, and a N-glycosylation site caused by S246Y and V247I mutations in another epitope. Besides, the analysis of selection pressure have found 8 positive selected sites (w = 9.59) using the codon-based substitution models and maximum-likelihood methods. These studies underscore the importance of this Env region for the virus fitness, for the host immune response and, therefore, for the development of vaccine candidates.

A clinical trial for uniform multidrug therapy for leprosy patients in Brazil: rationale and design

Leprosy will continue to be a public health problem for several decades. The World Health Organization (WHO) recommends that, for treatment purposes, leprosy cases be classified as either paucibacillary or multibacillary (MB). A uniform leprosy treatment regimen would simplify treatment and halve the treatment duration for MB patients. The clinical trial for uniform multidrug therapy (U-MDT) for leprosy patients (LPs) in Brazil is a randomised, open-label clinical trial to evaluate if the effectiveness of U-MDT for leprosy equals the regular regimen, to determine the acceptability of the U-MDT regimen and to identify the prognostic factors. This paper details the clinical trial methodology and patient enrolment data. The study enrolled 858 patients at two centres and 78.4% of participants were classified as MB according to the WHO criteria. The main difficulty in evaluating a new leprosy treatment regimen is that no reliable data are available for the current treatment regimen. Relapse, reaction and impaired nerve function rates have never been systematically determined, although reaction and impaired nerve function are the two major causes of nerve damage that lead to impairments and disabilities in LPs. Our study was designed to overcome the need for reliable data about the current treatment and to compare its efficacy with that of a uniform regimen.

Structure-based drug design studies of the interactions ofent-kaurane diterpenes derived from Wedelia paludosa with the Plasmodium falciparumsarco/endoplasmic reticulum Ca2+-ATPase PfATP6

Malaria is responsible for more deaths around the world than any other parasitic disease. Due to the emergence of strains that are resistant to the current chemotherapeutic antimalarial arsenal, the search for new antimalarial drugs remains urgent though hampered by a lack of knowledge regarding the molecular mechanisms of artemisinin resistance. Semisynthetic compounds derived from diterpenes from the medicinal plant Wedelia paludosawere tested in silico against the Plasmodium falciparumCa2+-ATPase, PfATP6. This protein was constructed by comparative modelling using the three-dimensional structure of a homologous protein, 1IWO, as a scaffold. Compound 21 showed the best docking scores, indicating a better interaction with PfATP6 than that of thapsigargin, the natural inhibitor. Inhibition of PfATP6 by diterpene compounds could promote a change in calcium homeostasis, leading to parasite death. These data suggest PfATP6 as a potential target for the antimalarial ent-kaurane diterpenes.

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.

A visão do estudante de enfermagem sobre o desenvolvimento do estágio curricular no período noturno

Estudo preliminar baseado no método qualitativo visando conhecer a opinião dos estudantes de Enfermagem do 7º período sobre o desenvolvimento do estágio no período noturno. Foram identificados nos trinta relatos os seguintes aspectos: importância da experiência; participação da enfermeira e da equipe de saúde; e diferença entre o período diurno e noturno. A maioria dos relatos demonstrou que a experiência foi válida devido apenas ao relacionamento da enfermeira e da equipe de saúde, e que não houve uma contribuição efetiva no aprendizado. Os relatos destacaram a diferença entre a assistência de enfermagem nos dois períodos. Concluiu-se que é necessário um debate amplo do corpo docente e discente sobre os objetivos do estágio no período noturno como uma das experiências curriculares para a formação profissional.

Estágio curricular em enfermagem: transição de identidades

A experiência do "Estágio Curricular" no Departamento de Enfermagem Materno-Infantil e Psiquiátrica da Escola de Enfermagem da Universidade de São Paulo (EEUSP), é relatada não só como uma inovação para atender às exigências do Currículo Mínimo em Enfermagem, como para dar consistência à formação pretendida com o novo currículo da EEUSP. A proposta é de possibilitar ao aluno vivenciar um processo de transição do ser estudante para o ser profissional. As autoras fazem uma análise retrospectiva de como a experiência tem sido vivenciada pelos envolvidos - graduando, docente e enfermeiro assistencial, tecendo considerações acerca dos resultados que evidenciam indicadores de autonomia e de responsabilidade do futuro profissional.

Desafios da formação em enfermagem no Brasil: proposta curricular da EEUSP para o bacharelado em enfermagem

O atual currículo do curso de graduação em Enfermagem da Escola de Enfermagem da USP está sendo reformulado e sua implantação está prevista para 2009. Este artigo tem por objetivo apresentar, em linhas gerais, o novo currículo do curso de graduação em Enfermagem da EEUSP. A estrutura proposta está dividida em três ciclos: Básico (1.500 horas), Intermediário (1.500 horas) e Complementar (1.000 horas), com carga horária total de 4.000 horas, ministrada em oito semestres letivos. A mudança visa a aumentar a integração entre as disciplinas e os departamentos, a autonomia do estudante e adotar a formação para o Sistema Único de Saúde como orientação geral do currículo. O novo currículo está voltado à formação da enfermeira generalista, com competência técnica, científica e ético-política para prestar cuidados de enfermagem a indivíduos, famílias e grupos sociais.

Reações comunicativas dos alunos de enfermagem frente ao primeiro estágio curricular

Este estudo tem como objetivo descrever as reações que os alunos de enfermagem apresentaram quando do seu primeiro estágio curricular. É um estudo transversal e de campo, e o tratamento dos dados foi realizado com base no método de análise de conteúdo. Os resultados descrevem o campo de estágio, o relacionamento com a equipe da enfermaria, com os pacientes e com o docente durante este período. Nas conclusões, podemos afirmar que o estresse e as contradições vivenciadas no primeiro estágio são parte do crescimento e aprendizado do aluno. O professor é maior responsável por determinar o tipo de interação que haverá entre ele e o aluno, cabendo-lhe ouvir, incentivar e capacitar-se para apoiar os alunos nas experiências iniciais da prática, para que o primeiro estágio seja um fator motivador ao aluno.

Problemas éticos vivenciados no estágio curricular supervisionado em Enfermagem de um currículo integrado

Estudo exploratório, de abordagem qualitativa, com o objetivo de analisar a repercussão do estágio curricular supervisionado no desenvolvimento da dimensão ética da competência de graduandos em Enfermagem. Entrevistas semiestruturadas foram realizadas com 28 estudantes, docentes e enfermeiros colaboradores de uma instituição de ensino superior pública do estado de São Paulo, no período de outubro de 2010 a março de 2011. O material empírico resultante foi submetido à técnica de análise de discurso e resultou nas categorias empíricas: a preservação da autonomia; a responsabilidade social e o respeito nas relações intersubjetivas na produção do cuidado em saúde e no processo de ensino e aprendizagem; a terapêutica e o cuidado a partir da dimensão ética; a responsabilidade pública e a justiça social. Concluiu-se que o estágio que utiliza a problematização como método de ensino e aprendizagem proporciona a reflexão crítica sobre a prática profissional, os serviços e o sistema de saúde.