Plasmodium falciparum drug resistance in Angola

Facing chloroquine drug resistance, Angola promptly adopted artemisinin-based combination therapy as the first-line to treat malaria. Currently, the country aims to consolidate malaria control, while preparing for the elimination of the disease, along with others African countries in the region. However, the remarkable capacity of Plasmodium to develop drug resistance represents an alarming threat for those achievements. Herein, the available, but relatively scarce and dispersed, information on malaria drug resistance in Angola, is reviewed and discussed. The review aims to inform but also to encourage future research studies that monitor and update the information on anti-malarial drug efficacy and prevalence of molecular markers of drug resistance, key fields in the context and objectives of elimination.

A farmacogenética e a medicina personalizada

A farmacogenética tem por objetivo a identificação de diferenças genéticas entre indivíduos que possam influenciar a resposta à terapêutica farmacológica, melhorando a sua eficácia e segurança. Associado à farmacogenética surge a “medicina personalizada”, ou seja, em oposição à existência de um fármaco que consiga tratar todos os pacientes, o tratamento individualizado parece o caminho mais promissor, uma vez que reduz o risco de reações adversas por toxicidade (segurança), adequa a dose ao indivíduo, evitando excessos ou défices (dose) e evita a metodologia de tentativa erro na escolha do fármaco (eficácia). A farmacogenética é relevante para a resposta individual ao fármaco por duas vias distintas: a farmacocinética e a farmacodinâmica. A variabilidade genética pode afetar a forma como um fármaco pode ser absorvido, ativado, metabolizado ou excretado, podendo conduzir assim a uma variabilidade na resposta. De entre o número infindável de possíveis exemplos, nesta revisão apresentam-se exemplos relacionados com os genes do Citocromo P450, do gene NAT2 e do gene da Colinesterase. As diferenças genéticas entre os indivíduos podem ainda afetar a resposta ao fármaco pela sua farmacodinâmica, ou seja, a resposta específica do alvo ao fármaco. De entre a multiplicidade de alvos de fármacos existentes serão apresentados exemplos do gene da G6PD e do VKORC1. Apesar de alguns dados científicos indicarem benefício para o paciente, ainda está longe de a farmacogenética fazer parte da prática clínica de rotina, talvez porque os custos-benefícios ainda não foram avaliados de forma precisa.

Drug susceptibility of Plasmodium falciparum in the western Amazon region, state of Acre, Brazil

Field studies in the western Amazon region (state of Acre, Brazil) indicate that the 4-aminoquinolines, as well as the combined regimen with sulfadoxine-pyrimethamine, can no longer be recomended for the treatment and prophylaxis of P. falciparum infections in this region. Quinine remains an effective drug when used correctly. However, compliance problems arise due to the often occurring side-effects during a ten day regimen. Prospects of overcoming these constraints by combining a short course of quinine with other drugs are limited, because of the lack of suitable partner compounds. For this reason quinine/clindamycin appears to be a more practical therapy of P. falciparum malaria. In vitro data from this study suggest that mefloquine is another effective alternative for the treatment of falciparum malaria in this Amazon region.

Prevalência do consumo de drogas ilícitas nas Forças Armadas estudo epidemiológico num dos ramos

RESUMO: Desde 1976 que as Forças Armadas desenvolvem acções de prevenção do consumo de drogas e álcool. Na década de 80 foi criada capacidade laboratorial e deu-se início a um programa de rastreios toxicológicos. No quinquénio 2001 a 2005, as proporções de resultados positivos, associando todos os tipos de rastreio, variaram entre 3,7% e 1,5%. De Outubro de 2006 a Julho de 2007 realizou-se um estudo analítico transversal, para estimar a prevalência do consumo de drogas (canabinóides, opiáceos, cocaína e anfetaminas) num dos Ramos das Forças Armadas, com base nos despistes realizados pelo seu laboratório. Foi utilizada uma amostra aleatória simples de 1039 militares, profissionais (QP) e contratados (RC), no activo e de ambos os sexos. Desde a nomeação dos militares a rastrear, passando pela cadeia de custódia das amostras até à obtenção do resultado foi utilizado apoio informático específico. O processo de pesquisa utilizou duas técnicas de triagem por imunoensaio e tecnologia de confirmação por GC/MS, de acordo com as recomendações europeias, permitindo estabelecer uma metodologia standard para organizações e empresas. A prevalência estimada, de consumidores de droga, foi de 3,8/1.000, para um erro de 0,37%. O número de casos registado (4) não permitiu a utilização de testes estatísticos que conduzissem à identificação de características determinantes da positividade, mas não deixou de revelar aspectos inesperados. A observação de séries de casos e a realização regular de estudos epidemiológicos, que ajudem a redefinir grupos alvo e a perceber a dimensão, as determinantes e as consequências do consumo de drogas é sugerida, em conclusão.--------------------------------------- RÉSUMÉ: Depuis 1976, les Forces Armées mettent au point des mesures visant à prévenir la consommation de drogues et d'alcool. En 1980, fut créé capacité laboratoriel et ont ensuite commencé un programme de dépistage toxicologique. Au cours des cinq années allant de 2001 à 2005, les proportions de consommateurs, impliquant tous les types de dépistage, allaient de 3,7% à 1,5 %. D'octobre 2006 à juillet 2007, une étude analytique transversale a été organisée pour évaluer la prévalence de l’usage de drogues (cannabis, opiacés, cocaïne et amphétamines) dans une branche de les Forces Armées, basée sur les dépistages faites par un laboratoire militaire, à l'aide d'un échantillon aléatoire de 1039 militaires, professionnels (QP) et sous contract (RC), à l’actif et des deux sexes. Tout au long du procès, de la nomination des donneurs, en passant par la chaine de garde des échantillons, jusqu’à obtention du résultat, il fut employé un appui informatique sécurisé. Le processus de recherche employa deux techniques de tri par imunoessay et la technologie de confirmation GC/MS, selon les recommandations européennes, permettant d'établir une méthodologie standard pour les organisations et les entreprises. La prévalence estimée fut de 3,8/1.000 pour une marge d’erreur de 0,37%. Le nombre de cas enregistrés (4) n'autorise pas l'utilisation de testes statistiques de menant à l'identification de caractéristiques déterminant de la positivité, mais il permet à révéler des aspects inattendus. L'observation de séries de cas et la tenue régulière d’études épidémiologiques, qui contribuent à redéfinir les groupes cibles et de comprendre l'ampleur, les déterminants et les conséquences de l'usage de drogues, est suggéré, en fin de compte.--------------------------------------- ABSTRACT: Since 1976, the Armed Forces, have been developing measures to prevent the use of drugs and alcohol. In 1980, was created laboratory facility which then started a program of toxicological screenings. In the five years running from 2001 to 2005, the proportions of consumers, involving all types of screening, ranged from 3,7% to 1,5%. From October 2006 to July 2007, a cross-sectional study was held to estimate the prevalence of drug use (cannabinoids, opiates, cocaine and amphetamines) in one branch of the Portuguese Armed Forces, based on laboratory screenings, using a random sample of 1039 military, professional (QP) and enlisted (RC), active-duty and of both sexes. Specific computer support was used all the way, from the appointment, including the chain of custody of samples, to the obtaining of the result. The process of search used two techniques for sorting by immunoassay and confirmation technology GC/MS, according to European recommendations, allowing to establish a standard methodology for organizations and companies. The estimated prevalence of drug users was 3.8/1.000 for a 0.37% error (95% confidence interval). The number of cases registered (4) does not permit use of statistical testing leading to the identification of characteristics weighing in the establishing to extrapolate for the population, but it allows revealing unexpected aspects. The observation of series of cases and the regular holding of epidemiological studies, which help redefine target groups and to understand the extent, the determinants and consequences of drug use, is suggested, in conclusion.

Evolution of Drug Resistance: Insight on TEM -Lactamases Structure and Activity and Beta-Lactam Antibiotics

Extended-spectrum β-lactamases (ESBLs) prevalence was studied in the north of Portugal, among 193 clinical isolates belonging to citizens in a district in the boundaries between this country and Spain from a total of 7529 clinical strains. In the present study we recovered some members of Enterobacteriaceae family, producing ESBL enzymes, including Escherichia coli (67.9%), Klebsiella pneumoniae (30.6%), Klebsiella oxytoca (0.5%), Enterobacter aerogenes (0.5%), and Citrobacter freundii (0.5%). β-lactamases genes blaTEM, blaSHV, and blaCTX-M were screened by polymerase chain reaction (PCR) and sequencing approaches. TEM enzymes were among the most prevalent types (40.9%) followed by CTX-M (37.3%) and SHV (23.3%). Among our sample of 193 ESBL-producing strains 99.0% were resistant to the fourth-generation cephalosporin cefepime. Of the 193 isolates 81.3% presented transferable plasmids harboring genes. Clonal studies were performed by PCR for the enterobacterial repetitive intragenic consensus (ERIC) sequences. This study reports a high diversity of genetic patterns. Ten clusters were found for E. coli isolates and five clusters for K. pneumoniae strains by means of ERIC analysis. In conclusion, in this country, the most prevalent type is still the TEM-type, but CTX-M is growing rapidly.

Nonlinear dynamics of the patient’s response to drug effect during general anesthesia

In today’s healthcare paradigm, optimal sedation during anesthesia plays an important role both in patient welfare and in the socio-economic context. For the closed-loop control of general anesthesia, two drugs have proven to have stable, rapid onset times: propofol and remifentanil. These drugs are related to their effect in the bispectral index, a measure of EEG signal. In this paper wavelet time–frequency analysis is used to extract useful information from the clinical signals, since they are time-varying and mark important changes in patient’s response to drug dose. Model based predictive control algorithms are employed to regulate the depth of sedation by manipulating these two drugs. The results of identification from real data and the simulation of the closed loop control performance suggest that the proposed approach can bring an improvement of 9% in overall robustness and may be suitable for clinical practice.

Drug resistance of M. Tuberculosis isolated from patients with HIV infection seen at an AIDS Reference Center in São Paulo, Brazil

M. tuberculosis-positive cultures were obtained from 228 patients seen in our service and drug sensitivity assays were carried out from January 1992 to December 1994. A survey of the medical records of these patients showed resistance to one or more drugs in 47 (20.6%), 25 of whom (10.9%), who reported previous treatment, were considered to have acquired resistance. Among the antecedents investigated, only previous treatment and alcoholism were the factors independently associated with the occurrence of resistance. The survival of patients with resistant strains was lower than that of patients attacked by non-resistant M. tuberculosis. We conclude that in the present series M. tuberculosis resistance to tuberculostatic agents was predominantly of the acquired type.

Etiological drug treatment of human infection by Trypanosoma cruzi

Forty-nine American Trypanosomiasis (Chagas' disease) patients, with xenodiagnosis proven parasitemia were treated by the authors. Forty-one of these patients were given benznidazole, at dosages ranging from 5mg/kg/day to 8mg/kg/day, during a pre-established period of 60 days. In this group, 17 patients had an undetermined form of the disease, whereas 22 had cardiologic disease and 4 had digestive disease (two patients had a mixed form of the disease). Side effects were frequent, and led to the discontinuation of treatment in 17 patients. The follow-up period ranged from 1 to 20 years (mean follow-up period of 6 yrs. 7 mo). 26 (63.4%) of the patients became parasitemia-negative. The other eight patients were treated with nifurtimox, during 120 days, following a variable dose regime of 5mg/kg/day (initial dose) to 17 mg/kg/day (final dose). Six of them had severe side effects, and only one patient remained parasitemia-negative throughout the observation period (ranging from 1 to 18 years). Benznidazole proved to be better tolerated and more effective in the management of parasitemia when compared to nifurtimox, although more effective and less toxic drugs are still desirable.

Candidin: comparison of two antigens for cutaneous delayed hypersensitivity testing

A candidin, which is a suspension of killed yeast cells, is commonly used for intradermal tests of delayed hypersensitivity, to evaluate the immunological cellular competence of the patient, when the test is applied along with other similar tests. When working with a cellular antigen, the histopathology of positive skin tests reveals a cellular infiltrate which not only presents a characteristic hypersensitivity reaction but also a neutrophilic abscess in the central part. This research presents the results of a comparison between the yeast cell suspension and the polysaccharide antigens, both obtained from the same strains of Candida albicans. The results obtained by skin tests in one hundred individuals were 61.0% with the polysaccharide antigen and 69.0% with the yeast cell suspension antigen. Concordant results concerning the two antigens were observed in 82.0% of the individuals. The discussion section presents an assumption to explain the differences of positivity obtained with the two antigens. We conclude that the polysaccharide antigen can be utilized in the intradermal test of delayed hypersensitivity to Candida albicans.

In vitro susceptibility testing of Fonsecaea pedrosoi to antifungals

Based on the difficulties experienced in the treatment of chromoblastomycosis, 12 primary human isolates of F. pedrosoi, were tested for their in vitro susceptibility to various antimycotics. We adapted the recommendations of the NCCLS for yeasts and followed the indications for mold testing from other authors in order to determine their MIC’s and the MLC’s. It was found that a significant proportion of the isolates were resistant to 3 of the 4 antimycotics tested, as revealed by high MIC values, as follows: 33% were resistant to amphotericin B (AMB), 58.3% to 5 fluocytosine (5 FC) and 66.7% to fluconazole (FLU). Contrarywise, none of the isolates proved resistant to itraconazole (ITZ). Determination of the MLC’s revealed that a larger proportion of the isolates were not killed by AMB, 5 FC (91.7%), FLU (100%) or even, ITZ (41.7%). These data indicate that it would be desirable to determine the susceptibility of F. pedrosoi before initiating therapy, in order to choose the more effective antifungal and avoid clinical failure

Evolution of Drug Resistance: Insight on TEM β-Lactamases Structure and Activity and β-Lactam Antibiotics

Since the discovery of the first penicillin bacterial resistance to β-lactam antibiotics has spread and evolved promoting new resistances to pathogens. The most common mechanism of resistance is the production of β-lactamases that have spread thorough nature and evolve to complex phenotypes like CMT type enzymes. New antibiotics have been introduced in clinical practice, and therefore it becomes necessary a concise summary about their molecular targets, specific use and other properties. β-lactamases are still a major medical concern and they have been extensively studied and described in the scientific literature. Several authors agree that Glu166 should be the general base and Ser70 should perform the nucleophilic attack to the carbon of the carbonyl group of the β-lactam ring. Nevertheless there still is controversy on their catalytic mechanism. TEMs evolve at incredible pace presenting more complex phenotypes due to their tolerance to mutations. These mutations lead to an increasing need of novel, stronger and more specific and stable antibiotics. The present review summarizes key structural, molecular and functional aspects of ESBL, IRT and CMT TEM β-lactamases properties and up to date diagrams of the TEM variants with defined phenotype. The activity and structural characteristics of several available TEMs in the NCBI-PDB are presented, as well as the relation of the various mutated residues and their specific properties and some previously proposed catalytic mechanisms.

The role of molecular imaging in modern drug development

Drug development represents a highly complex, inefficient and costly process. Over the past decade, the widespread use of nuclear imaging, owing to its functional and molecular nature, has proven to be a determinant in improving the efficiency in selecting the candidate drugs that should either be abandoned or moved forward into clinical trials. This helps not only with the development of safer and effective drugs but also with the shortening of time-to-market. The modern concept and future trends concerning molecular imaging will assumedly be hybrid or multimodality imaging, including combinations between high sensitivity and functional (molecular) modalities with high spatial resolution and morphological techniques.

Massive shift in the pneumococcal nasopharyngeal flora after the 7-valent conjugate vaccine: epidemiological studies and testing pathogenic potential in animal models

Dissertation presented to obtain the PhD degree in Biology/Molecular Biology by Universidade Nova de Lisboa, Instituto de Tecnologia Química e Biológica

O financiamento por capitação ajustada pelo risco em contexto de integração vertical de cuidados de saúde : a utilização dos consumos com medicamentos como proxy da carga de doença em ambulatório

RESUMO - Introdução - Com o presente projecto de investigação pretendeu-se estudar o financiamento por capitação ajustado pelo risco em contexto de integração vertical de cuidados de saúde, recorrendo particularmente a informação sobre o consumo de medicamentos em ambulatório como proxy da carga de doença. No nosso país, factores como a expansão de estruturas de oferta verticalmente integradas, inadequação histórica da sua forma de pagamento e a recente possibilidade de dispor de informação sobre o consumo de medicamentos de ambulatório em bases de dados informatizadas são três fortes motivos para o desenvolvimento de conhecimento associado a esta temática. Metodologia - Este trabalho compreende duas fases principais: i) a adaptação e aplicação de um modelo de consumo de medicamentos que permite estimar a carga de doença em ambulatório (designado de PRx). Nesta fase foi necessário realizar um trabalho de selecção, estruturação e classificação do modelo. A sua aplicação envolveu a utilização de bases de dados informatizadas de consumos com medicamentos nos anos de 2007 e 2008 para a região de Saúde do Alentejo; ii) na segunda fase foram simulados três modelos de financiamento alternativos que foram propostos para financiar as ULS em Portugal. Particularmente foram analisadas as dimensões e variáveis de ajustamento pelo risco (índices de mortalidade, morbilidade e custos per capita), sua ponderação relativa e consequente impacto financeiro. Resultados - Com o desenvolvimento do modelo PRx estima-se que 36% dos residentes na região Alentejo têm pelo menos uma doença crónica, sendo a capacidade de estimação do modelo no que respeita aos consumos de medicamentos na ordem dos 0,45 (R2). Este modelo revelou constituir uma alternativa a fontes de informação tradicionais como são os casos de outros estudos internacionais ou o Inquérito Nacional de Saúde. A consideração dos valores do PRx para efeitos de financiamento per capita introduz alterações face a outros modelos propostos neste âmbito. Após a análise dos montantes de financiamento entre os cenários alternativos, obtendo os modelos 1 e 2 níveis de concordância por percentil mais próximos entre si comparativamente ao modelo 3, seleccionou-se o modelo 1 como o mais adequado para a nossa realidade. Conclusão - A aplicação do modelo PRx numa região de saúde permitiu concluir em função dos resultados alcançados, que já existe a possibilidade de estruturação e operacionalização de um modelo que permite estimar a carga de doença em ambulatório a partir de informação relativa ao seu perfil de consumo de medicamentos dos utentes. A utilização desta informação para efeitos de financiamento de organizações de saúde verticalmente integradas provoca uma variação no seu actual nível de financiamento. Entendendo este estudo como um ponto de partida onde apenas uma parte da presente temática ficará definida, outras questões estruturantes do actual sistema de financiamento não deverão também ser olvidadas neste contexto. ------- ABSTRACT - Introduction - The main goal of this study was the development of a risk adjustment model for financing integrated delivery systems (IDS) in Portugal. The recent improvement of patient records, mainly at primary care level, the historical inadequacy of payment models and the increasing number of IDS were three important factors that drove us to develop new approaches for risk adjustment in our country. Methods - The work was divided in two steps: the development of a pharmacy-based model in Portugal and the proposal of a risk adjustment model for financing IDS. In the first step an expert panel was specially formed to classify more than 33.000 codes included in Portuguese pharmacy national codes into 33 chronic conditions. The study included population of Alentejo Region in Portugal (N=441.550 patients) during 2007 and 2008. Using pharmacy data extracted from three databases: prescription, private pharmacies and hospital ambulatory pharmacies we estimated a regression model including Potential Years of Life Lost, Complexity, Severity and PRx information as dependent variables to assess total cost as the independent variable. This healthcare financing model was compared with other two models proposed for IDS. Results - The more prevalent chronic conditions are cardiovascular (34%), psychiatric disorders (10%) and diabetes (10%). These results are also consistent with the National Health Survey. Apparently the model presents some limitations in identifying patients with rheumatic conditions, since it underestimates prevalence and future drug expenditure. We obtained a R2 value of 0,45, which constitutes a good value comparing with the state of the art. After testing three scenarios we propose a model for financing IDS in Portugal. Conclusion - Drug information is a good alternative to diagnosis in determining morbidity level in a population basis through ambulatory care data. This model offers potential benefits to estimate chronic conditions and future drug costs in the Portuguese healthcare system. This information could be important to resource allocation decision process, especially concerning risk adjustment and healthcare financing.