Chagas disease stroke and associated risk factors: A case-control study.

INTRODUCTION: The intricate relationship between Chagas disease and ischemic stroke remains unclear. Limited evidence exists concerning secondary prophylaxis, etiological diagnosis, and stroke-related determinants. This study aims to discern factors linked to stroke in Chagas disease by contrasting patients with and without a history of ischemic stroke. METHODS: Retrospective data from all outpatient Chagas disease patients from two Brazilian hospitals - one Chagas center and one stroke clinic - were examined. Descriptive analyses were conducted to identify stroke-associated factors. Variables were compared between patients with and without ischemic stroke history. RESULTS: Among 678 subjects, 72 had experienced stroke. Univariate associations with stroke included male gender, heart failure, prior or ongoing alcoholism, electrocardiographic features (non-sinus rhythm, left bundle branch, right bundle branch block, left anterosuperior fascicular block, atrial fibrillation), as well as echocardiographic findings indicative of reduced left ventricular ejection fraction and segmental abnormalities. After logistic regression (multivariate analysis), congestive heart failure, right bundle branch block, left anterosuperior divisional block, and atrial fibrillation retained independent associations. CONCLUSION: In this study, cardiac involvement emerged as the predominant factor correlated with stroke in Chagas disease. While atherosclerosis-related risk factors were prevalent, their influence on ischemic stroke in Chagas disease appeared limited.

Prevalence of human papillomavirus, Chlamydia trachomatis, and Trichomonas vaginalis infections in Amazonian women with normal and abnormal cytology.

Sexually transmitted infections are an important cause of morbidity among sexually active women worldwide, and have been implicated as cofactors in the pathogenesis of cervical cancer. We investigated the prevalence of human papillomavirus (HPV), Chlamydia trachomatis (CT), and Trichomonas vaginalis (TV), and accessed the diversity of HPV in women with normal and abnormal cytology in Manaus, Brazil. We used polymerase chain reaction and HPV genotyping by direct sequencing. The chi-square test was used to calculate the absolute and relative frequencies of the categorical variables, and Fisher's test was used when P < 0.05. The level of significance was set at 5%. All statistical analyses were performed using R 2.9.0. There were statistically significant differences in age (P = 0.0395), education level (P = 0.0131), sexual partners (P = 0.0211), condom use (P = 0.0039), marital status (P < 0.0001), and pregnancy (P = 0.0003) between the normal and abnormal groups. HPV DNA was found in 36.56 and 93.88% of subjects in the normal and abnormal groups, respectively. A total of 19 genotypes were detected; HPV16 was the most common, followed by HPV58. The percentages of TV and CT DNA were 18.04 and 9.02% in the normal group, respectively. The percentages of HPV/TV and HPV/CT coinfection were 12.5% each in women with normal cytology. These findings improve our understanding of HPV, CT, and TV, and the distribution of HPV types, which may be relevant to vaccination strategies for protecting women from the north of Brazil from cervical cancers and precancerous lesions.

Postoperative decrease in plasma sodium concentration after infusion of hypotonic intravenous solutions in neonatal surgery.

BACKGROUND: Hypotonic i.v. solutions can cause hyponatraemia in the context of paediatric surgery. However, this has not been demonstrated in neonatal surgery. The goal of this study was to define the relationship between infused perioperative free water and plasma sodium in neonates. METHODS: Newborns up to 7 days old undergoing abdominal or thoracic surgery were included in this prospective, observational study. Collected data included type and duration of surgery, calculated i.v. free water intake, and pre- and postoperative plasma sodium. Statistical analyses were performed using the Pearson correlation, Mann-Whitney test, and receiver operating characteristic analysis with a 1000 time bootstrap procedure. RESULTS: Thirty-four subjects were included. Postoperative hyponatraemia occurred in four subjects (11.9%). The difference between preoperative and postoperative plasma sodium measurements (ΔNaP) correlated with calculated free water intake during surgery (r=0.37, P=0.03), but not with preoperative free water intake. Calculated operative free water intake exceeding 6.5 ml kg(-1) h(-1) was associated with ΔNaP≥4 mM with a sensitivity and specificity [median (95% confidence interval)] of 0.7 (0.9-1) and 0.5 (0.3-0.7), respectively. CONCLUSIONS: Hypotonic solutions and i.v. free water intake of more than 6.5 ml kg(-1) h(-1) are associated with reductions in postoperative plasma sodium measurements ≥4 mM. In the context of neonatal surgery, close monitoring of plasma sodium is mandatory. Routine use of hypotonic i.v. solutions during neonatal surgery should be questioned as they are likely to reduce plasma sodium.

Reduced step edges on rutile TiO2(110) as competing defects to oxygen vacancies on the terraces and reactive sites for ethanol dissociation.

The rutile TiO2(110) surface is the most studied surface of titania and considered as a prototype of transition metal oxide surfaces. Reactions on flat TiO2(110)-(1×1) surfaces are well studied, but the processes occurring on the step edges have barely been considered. Based on scanning tunneling microscopy studies, we here present experimental evidence for the existence of O vacancies along the [11¯1](R) step edges (O(S) vac.'s) on rutile TiO(2)(110). Both the distribution of bridging O vacancies on the terraces and temperature-programed reaction experiments of ethanol-covered TiO(2)(110) point to the existence of the O(S) vac.'s. Based on experiments and density functional theory calculations, we show that O(S) vac.'s are reactive sites for ethanol dissociation via O-H bond scission. Implications of these findings are discussed.

Direct evidence for ethanol dissociation on rutile TiO2(110).

We have studied the interaction of ethanol with reduced TiO(2)(110)-(1 × 1) by high-resolution scanning tunneling microscopy (STM) measurements and density functional theory calculations. The STM data revealed direct evidence for the coexistence of molecularly and dissociatively adsorbed ethanol species on surface Ti sites. In addition, we found evidence for dissociation of ethanol at bridge-bonded O vacancies. The density functional theory calculations support these findings and rationalize the distinct diffusion behaviors of molecularly and dissociatively adsorbed ethanol species, as revealed in time-lapsed STM images.

Organization of a tumor bank: the experience of the National Cancer Institute of Mexico.

A tumor bank (TB) is an ordered collection of neoplastic samples, normal tissue, and/or fluids preserved under optimal conditions, as well as storing patients' clinical information. The objective of this article is to outline the planning and logistics necessary for the functioning of the Instituto Nacional de Cancerología (INCan) TB in Mexico City. For the planning and logistics of a TB, several technical, legal, medical, structural, and physical aspects were considered, which can be grouped under four headings: (1) design and structure, (2) equipping the area and informatics, (3) ethical-legal aspects, and (4) sample collection, preservation, and quality control. One crucial element of interinstitutional interest will be the transfer of these concepts to the different oncological centers, integrating in this manner a network that enables the exploration of the different pathologies from therapeutic, epidemiological, and molecular points of view.

Quality of life related to oral health of patients undergoing hemodialysis and associated factors.

PURPOSE: To evaluate quality of life related to oral health (QoLROH) of Brazilians undergoing hemodialysis and to identify associated factors. MATERIAL AND METHODS: A cross-sectional study was conducted with 226 patients undergoing hemodialysis at two reference medical centers. Participants answered a sociodemographic questionnaire and the Brazilian version of the Oral Health Impact Profile (OHIP-14). Descriptive and multivariate statistics using Decision Tree Analysis by the Chi-square Automatic Interaction Detector (CHAID) algorithm, as well as Ordinal Logistic Regression analyses were performed. RESULTS: The Decision Tree revealed that the impact on QoLROH could be explained by age (p = 0.002), tooth pain in the last 6 months (p = 0.026), and region of residence (p = 0.025). CONCLUSIONS: The results suggest that being older, living in rural areas, and reporting tooth pain in the last 6 months may influence the QoLROH of patients undergoing hemodialysis.

Saúde do idoso no contexto do crescimento populacional e das legislações: uma pesquisa ex-post-facto / Health of the elderly in the context of population growth and legislation: an ex-post-fact research / Salud de las personas mayores en el contexto del crecimiento de la población y la legislación: una investigación ex-post-hecho

Objetivo: Conhecer a realidade da atenção à saúde dos idosos no município de João Pessoa no período de 2002 a 2012 iluminando a correlação entre os fenômenos do crescimento populacional e as legislações específicas sobre o tema. Métodos: Trata-se de uma pesquisa do tipo ex-post-factor relacionando a descrição de fatos já ocorridos e seu significado na prática. Resultados: As Portarias 702 de 12/04/2002 e 249 de 16/04/2002, ambas do Ministério da Saúde, criaram, respectivamente, as Redes Estaduais de Assistência à Saúde do Idoso e os Centros de Referência em Atenção à Saúde do Idoso, que não superaram os problemas desta área, devido as carências estruturais (materiais) e profissionais (humanas) dos hospitais gerais. Conclusão: A solução jurídica proposta nas Portarias não se efetivaram e o contingente de idosos do município de João Pessoa encontra-se desamparado, em termos de aportes estruturais e profissionais. (AU)

Objective: Know the reality of health care for the elderly in the city of João Pessoa from 2002 to 2012, highlighting the correlation between the phenomena of population growth and the specific legislation on the subject. Methods: This is an ex-post-factor type research relating the description of facts that have already occurred and their meaning in practice. Results: Ordinances 702 of 12/04/2002 and 249 of 16/04/2002, both from the Ministry of Health, created, respectively, the State Health Assistance Networks for the Elderly and the Reference Centers in Elderly Health Care, who have not overcome the problems in this area, due to the structural (material) and professional (human) deficiencies of general hospitals. Conclusion: The legal solution proposed in the Ordinances has not been implemented and the contingent of elderly people in the city of João Pessoa is helpless, in terms of structural and professional contributions. (AU)

Objetivo: Conocer la realidad de la atención de la salud de las personas mayores en la ciudad de João Pessoa de 2002 a 2012, destacando la correlación entre los fenómenos de crecimiento poblacional y la legislación específica sobre el tema. Métodos: Se trata de una investigación de tipo ex post factorial que relaciona la descripción de hechos que ya han ocurrido y su significado en la práctica. Resultados: Las Ordenanzas 702 de 04/12/2002 y 249 de 16/04/2002, ambas del Ministerio de Sanidad, crearon, respectivamente, las Redes Estatales de Asistencia Sanitaria para Personas Mayores y los Centros de Referencia en Atención Sanitaria para Personas Mayores, que no han superar los problemas en esta área, debido a las deficiencias estructurales (materiales) y profesionales (humanas) de los hospitales generales. Conclusión: La solución legal propuesta en las Ordenanzas no se ha implementado y el contingente de ancianos en la ciudad de João Pessoa está indefenso, en términos de aportes estructurales y profesionales. (AU)

Sexualidade comprometida em pacientes prostatectomizados: mito ou verdade? / Compromised sexuality in prostatectomy patients: myth or truth? / Sexualidad comprometida en pacientes con prostatectomía: mito o verdad?

Objetivo: Verificar se os pacientes prostatectomizados são informados sobre a possibilidade de superação da perda da função erétil pelos benefícios da sexualidade humana após a intervenção cirúrgica. Métodos: A técnica utilizada foi a análise temática que consiste na busca dos núcleos de sentido para se construir uma comunicação. O estudo foi realizado em um hospital de referência no tratamento de câncer e envolveu pacientes prostatectomizados no pós-operatório mediato. Resultados: A perda da função erétil pode ser superada pela utilização da sexualidade humana materializada no amor, carinho e compreensão. Conclusão: A escassez de informações sobre os efeitos da prostatectomia em pacientes cirúrgicos inaugura uma contradição no processo de atenção à saúde aos portadores de câncer de próstata. A contradição, advém do fato de que a resposta a esta questão admite as duas possibilidades, mito e verdade. (AU)

Objective: To verify whether prostatectomy patients are informed about the possibility of overcoming the loss of erectile function due to the benefits of human sexuality after surgical intervention. Methods: The technique used was thematic analysis, which consists of the search for meaning cores to build communication. The study was carried out in a reference hospital for the treatment of cancer and involved patients undergoing prostatectomy in the immediate postoperative period. Results: The loss of erectile function can be overcome by the use of human sexuality materialized in love, affection and understanding. Conclusion: The scarcity of information about the effects of prostatectomy in surgical patients opens a contradiction in the health care process for patients with cancer of prostate. The contradiction comes from the fact that the answer to this question admits the two possibilities, myth and truth. (AU)

Objetivo: Verificar si los pacientes prostatectomizados están informados sobre la posibilidad de superar la pérdida de la función eréctil por los beneficios de la sexualidad humana tras la intervención quirúrgica. Métodos: La técnica utilizada fue el análisis temático, que consiste en la búsqueda de núcleos de significado para construir la comunicación. El estudio se llevó a cabo en un hospital de referencia para el tratamiento del cáncer e involucró a pacientes sometidos a prostatectomía en el postoperatorio inmediato. Resultados: La pérdida de la función eréctil puede superarse mediante el uso de la sexualidad humana materializada en el amor, el afecto y la comprensión. Conclusión: La escasez de información sobre los efectos de la prostatectomía en pacientes quirúrgicos abre una contradicción en el proceso de atención de la salud de los pacientes con cáncer de próstata. La contradicción proviene del hecho de que la respuesta a esta pregunta admite las dos posibilidades, mito y verdad. (AU)

Construção do e-book "Conversando sobre coronavírus COVID-19" / Construction of the e-book "talking about coronavirus covid-19" / Construcción del libro electrónico "hablando sobre coronavirus covid-19"

Objetivo: descrever a experiência da construção do E-book sobre COVID-19 para o público em geral. Método: estudo descritivo, do tipo relato de experiência resultante das ações do Grupo de Estudos e Pesquisa em Saúde da Pessoa em Condições Críticas, consistiu no empenho acadêmico sobre os efeitos do SARS-CoV-2, causador da Pandemia. Todas as etapas da construção do E-book, foram elaboradas pelos autores, incluindo as ilustrações apresentadas. Realizou-se reuniões virtuais para discussão do tema, na sequência, a construção do material. Resultados: promoção do repasse de conhecimentos sobre a temática, de forma simples e acessível. Publicado pela editora do Conselho Federal de Enfermagem, Brasília-DF. O E-book contêm um total de cinquenta e sete páginas. ISBN: 978-65-87031-01-9 Conclusão: a construção desse material educativo foi uma forma de educação em saúde, levando orientações de fácil compreensão e acesso. As informações através de materiais didáticos auxiliam a população a preparar-se para esse enfrentamento. (AU)

Objective: To describe the experience of building the E-book on COVID-19 for the general public. Methods: A descriptive study, of the experience report type resulting from the actions of the Study Group and Research in Health of the Person in Critical Conditions consisted of the academic commitment on the effects of SARS-CoV-2, which causes Pandemic. All the stages of the construction of the E-book, were elaborated by the authors, including the presented illustrations. Virtual meetings were held to discuss the topic, followed by the construction of the material. Results: promoting the transfer of knowledge on the theme, in a simple and accessible way. Published by the publisher of the Federal Nursing Council, Brasília-DF. The E book contains a total of fifty-seven pages. Conclusion: the construction of this educational material was a form of health education, taking guidelines that are easy to understand and access. Information through didactic materials helps the population to prepare for this confrontation. (AU)

Objetivo: Describir la experiencia de construir el libro electrónico sobre COVID-19 para el público en general. Métodos: Estudio descriptivo, del tipo relato de experiencia resultante de las acciones del Grupo de Estudio e Investigación en Salud de la Persona en Condiciones Críticas, consistió en el compromiso académico sobre los efectos del SARS-CoV-2, causante de Pandemia. Todas las etapas de la construcción del E-book, fueron elaboradas por los autores, incluidas las ilustraciones presentadas. Se realizaron reuniones virtuales para discutir el tema, seguidas de la construcción del material. Resultados: Promover la transferencia de conocimientos sobre el tema, de forma sencilla y accesible. Publicado por la editorial del Consejo Federal de Enfermería, Brasilia-DF. El libro electrónico contiene un total de cincuenta y siete páginas. Conclusión: La construcción de este material educativo fue una forma de educación en salud, tomando pautas de fácil comprensión y acceso. La información a través de materiales didácticos ayuda a la población a prepararse para este enfrentamiento. (AU)

Mulheres mastectomizadas: fatores excludentes da reconstrução mamária / Mastectomized women: excluding factors of breast reconstruction

Objetivo: compreender os processos ou racionalidades dos fatores excludentes da reconstrução mamária em mulheres mastectomizadas. Métodos: trata-se de investigação do tipo exploratória e descritiva, com abordagem qualitativa, desenvolvido no hospital Napoleão Laureano em João Pessoa - Paraíba, com amostra de 10 mulheres mastectomizadas no pós-operatório imediato. Resultados: após a coleta dos depoimentos, estabeleceram­se as categorias a partir da análise de conteúdo, que foram: desconhecimento acerca da reconstrução mamária pós-mastectomia; medo de complicações posteriores e falta de desejo na colocação da prótese mamária. Quanto ao tipo de mastectomia, apenas 20% realizaram a reconstrução mamária imediata. Conclusão: evidenciou-se que houve falha de comunicação pelos profissionais em informar os direitos garantidos por leis a essas mulheres, mesmo que suas condições clínicas sejam impeditivas para a realização do procedimento. Apesar da conquista da Lei Federal que garante a reconstrução mamária, existem mulheres que optam pela não realização, seja por medo ou conformismo da cura. (AU)

Objective: to understand the processes or rationalities of excluding factors in breast reconstruction in mastectomized women. Method: this is an exploratory and descriptive research with a qualitative approach, developed at Napoleão Laureano hospital in João Pessoa - Paraíba, with a sample of 10 women who had mastectomies in the immediate postoperative period. Results: after collecting the testimonies, the categories were established from the content analysis, which were ignorance about breast reconstruction after mastectomy; fear of further complications and lack of desire for breast implant placement. regarding the type of mastectomy, only 20% underwent immediate breast reconstruction. Conclusion: it was evidenced that there was a failure of professionals to communicate the rights guaranteed by law to these women, even if their clinical conditions are impeding the performance of the procedure. Despite the achievement of the federal law that guarantees breast reconstruction, there are women who choose not to perform, either for fear or for conformity of the cure. (AU)

Objetivo: comprender los procesos o las racionalidades de los factores excluyentes en la reconstrucción mamaria en mujeres mastectomizadas. Método: esta es una investigación exploratoria y descriptiva con un enfoque cualitativo, desarrollada en el hospital Napoleão Laureano en João Pessoa - Paraíba, con una muestra de 10 mujeres que tuvieron mastectomías en el postoperatorio inmediato. Resultados: después de recopilar los testimonios, se establecieron las categorías a partir del análisis de contenido, que eran ignorancia sobre la reconstrucción mamaria después de la mastectomía; miedo a otras complicaciones y falta de deseo de colocar implantes mamarios. En cuanto al tipo de mastectomía, solo el 20% se sometió a reconstrucción mamaria inmediata. Conclusión: se evidenció que los profesionales no pudieron comunicar los derechos garantizados por la ley a estas mujeres, incluso si sus condiciones clínicas impiden la realización del procedimiento. A pesar del logro de la Ley Federal que garantiza la reconstrucción mamaria, hay mujeres que optan por no realizar, ya sea por miedo o por la conformidad de la cura. (AU)

Expression and characterization of recombinant pyruvate phosphate dikinase from Entamoeba histolytica.

The parasite Entamoeba histolytica is an organism whose main energetic source comes from glycolysis. It has the singularity that several of its glycolytic enzymes use pyrophosphate as an alternative phosphate donor. Thus, pyruvate phosphate dikinase (PPDK), an inorganic pyrophosphate (PPi)-dependent enzyme, substitutes pyruvate kinase present in humans. We previously cloned and sequenced the gene that codifies for PPDK in E. histolytica. We now report its expression in a bacterial system and its purification to 98% homogeneity. We determined its K(m) for phosphoenolpyruvate, AMP and PPi (21, < 5 and 100 microM, respectively). Unlike PPDK from maize and bacteria and pyruvate kinase from other cells, EhPPDk is dependent on divalent cations but does not require monovalent cations for activity. The enzyme has an optimum pH of 6.0, it is labile to low temperatures and has a tetrameric structure. Since EhPPDK is a PPi-dependent enzyme, we also tested the effect of some pyrophosphate analogs as inhibitors of activity. Studies on the function and structure of this enzyme may be important for therapeutic research in several parasitic diseases, since it has no counterpart in humans.

Using evolutionary changes to achieve species-specific inhibition of enzyme action--studies with triosephosphate isomerase.

BACKGROUND: Many studies that attempt to design species-specific drugs focus on differences in the three-dimensional structures of homologous enzymes. The structures of homologous enzymes are generally well conserved especially at the active site, but the amino-acid sequences are often very different. We reasoned that if a non-conserved amino acid is fundamental to the function or stability of an enzyme from one particular species, one should be able to inhibit only the enzyme from that species by using an inhibitor targeted to that residue. We set out to test this hypothesis in a model system. RESULTS: We first identified a non-conserved amino acid (Cys14) whose integrity is important for catalysis in triosephosphate isomerase (TIM) from Trypanosoma brucei. The equivalent residues in rabbit and yeast TIM are Met and Leu, respectively. A Cys14Leu mutant of trypanosomal TIM had a tendency to aggregate, reduced stability and altered kinetics. To model the effects of a molecule targeted to Cys14, we used methyl methanethiosulfonate (MMTS) to derivatize Cys14 to a methyl sulfide. This treatment dramatically inhibited TIMs with a Cys residue at a position equivalent to Cys14, but not rabbit TIM (20% inhibition) or yeast TIM (negligible inhibition), which lack this residue. CONCLUSIONS: Cys14 of trypanosomal TIM is a non-conserved amino acid whose alteration leads to loss of enzyme structure and function. TIMs that have a cysteine residue at position 14 could be selectively inhibited by MMTS. This approach may offer an alternative route to species-specific enzyme inhibition.

Análise da articulação entre saúde do trabalhador e a atenção básica / Analysis of the joint between worker health and basic care

Objetivo: Analisar o processo de articulação entre o Centro de Referência em Saúde do Trabalhador e a Unidade Básica de Saúde. Método: Estudo exploratório, descritivo e observacional, com abordagem qualitativa utilizando a técnica de Análise de Discurso proposta de Fiorin, tendo como cenários da pesquisa o Centro de Referência em Saúde do Trabalhador, de João Pessoa e a Unidade Básica de Saúde Integrando Vidas. Resultados: Os usuários utilizam a Atenção Básica à Saúde como porta de entrada no sistema de saúde, porém, a maioria significativa dos profissionais participantes da pesquisa, apenas debelam os sintomas e não intervêm na origem dos problemas. Con­clusão: Foi revelada uma desarticulação preocupante entre a Atenção Básica à Saúde e o Centro de Referência em Saúde do Trabalhador e elencadas algumas propostas de intervenção no processo de trabalho visando a superação deste problema. (AU)

Objective: To analyze the process of articulation between the Reference Center for Occupational Health and the Basic Health Unit. Methods: Exploratory, descriptive and observational study, with a qualitative approach using the Discourse Analysis technique proposed by Fiorin, using the scenarios of researches the Reference Center in Occupational Health, João Pessoa and the Basic Health Unit Integrating Lives. Results: Users use Primary Health Care as a gateway to the health system, however, the significant majority of professionals participating in the research, only resolve the symptoms and do not intervene in the origin of the problems. Conclusion: A worrying disarticulation between Primary Health Care and the Reference Center for Occupational Health was revealed and some intervention proposals were listed in the work process aimed at overcoming this problem. (AU)

Objetivo: Analizar el proceso de articulación entre el Centro de Referencia en Salud Ocupacional y la Unidad Básica de Salud. Métodos: Estudio exploratorio, descriptivo y observacional, con abordaje cualitativo utilizando la técnica de Análisis del Discurso propuesta por Fiorin, utilizando los escenarios de las investigaciones del Centro de Referencia en Salud Ocupacional, João Pessoa y la Unidad Básica de Salud Integrando Vidas. Resultados: Los usuarios utilizan la Atención Primaria de Salud como puerta de entrada al sistema de salud, sin embargo, la gran mayoría de los profesionales que participan en la investigación, solo resuelven los síntomas y no intervienen en el origen de los problemas. Conclusión: se reveló una preocupante desarticulación entre la Atención Primaria de Salud y el Centro de Referencia en Salud Ocupacional y se enumeraron algunas propuestas de intervención en el proceso de trabajo encaminadas a superar esta problemática. (AU)

Cloning and sequence determination of the gene coding for the pyruvate phosphate dikinase of Entamoeba histolytica.

We isolated three overlapping clones from a DNA genomic library of Entamoeba histolytica strain HM1:IMSS, whose translated nucleotide (nt) sequence shows similarities of 51, 48 and 47% with the amino acid (aa) sequences reported for the pyruvate phosphate dikinases from Bacteroides symbiosus, maize and Flaveria trinervia, respectively. The reading frame determined codes for a protein of 886 aa.

Partial nucleotide sequence of the enzyme pyruvate, orthophosphate dikinase of Entamoeba histolytica HM1:IMSS.

We isolated a clone from a lambda gt11 cDNA library of E. histolytica, subcloned its insert in the vector pTZ18R and sequenced it by the method of Sanger. Sequence comparison with Genbank and of the corresponding amino acid sequence with the NBRF/PIR data bank using the FastA program, showed homologies between 54.9 and 58.5% for the nucleotides and between 48.6 and 49.4% for the amino acids with pyruvate, orthophosphate dikinases from maize, Flaveria trinervia and Bacteroides symbiosus. The sequence obtained for E. histolytica represents about 20% of the complete gene or protein sequence.

Energy production in Entamoeba histolytica: new perspectives in rational drug design.

The amebicidal action of metronidazole is activated when the enzyme pyruvate:ferredoxin oxido-reductase transfers reducing equivalents to the nitro group of the drug. The enzyme is present in Entamoeba histolytica and other anaerobic parasites like Giardia and Trichomonas that lack mitochondria. The selectivity of the drug can be ascribed to the absence of the reductase in the human host. E. histolytica possesses other enzymes involved in glucose catabolism that are interesting for the rational design of new drugs. It has glycolytic enzymes that are important for the production of energy like phosphofructokinase, pyruvate phosphate dikinase, phosphoenolpyruvate carboxytransphosphorylase and acetate thiokinase, which use pyrophosphate as a phosphate donor and have no human counterparts. The first part of this article describes the reactions by which E. histolytica obtains energy from glucose degradation, and includes recent advances in the cloning of genes for the various participating enzymes. The second part shows an alternative view for the study of target enzymes that are unique to the parasite, and indicates their importance in therapeutic research.