Neutrophils Reduce the Parasite Burden in Leishmania (Leishmania) amazonensis-Infected Macrophages

Background: Studies on the role of neutrophils in Leishmania infection were mainly performed with L. (L) major, whereas less information is available for L. (L) amazonensis. Previous results from our laboratory showed a large infiltrate of neutrophils in the site of infection in a mouse strain resistant to L. (L.) amazonensis (C3H/HePas). in contrast, the susceptible strain (BALB/c) displayed a predominance of macrophages harboring a high number of amastigotes and very few neutrophils. These findings led us to investigate the interaction of inflammatory neutrophils with L. (L.) amazonensis-infected macrophages in vitro.Methodology/Principal Findings: Mouse peritoneal macrophages infected with L. (L.) amazonensis were co-cultured with inflammatory neutrophils, and after four days, the infection was quantified microscopically. Data are representative of three experiments with similar results. the main findings were 1) intracellular parasites were efficiently destroyed in the co-cultures; 2) the leishmanicidal effect was similar when cells were obtained from mouse strains resistant (C3H/HePas) or susceptible (BALB/c) to L. (L.) amazonensis; 3) parasite destruction did not require contact between infected macrophages and neutrophils; 4) tumor necrosis factor alpha (TNF-alpha), neutrophil elastase and platelet activating factor (PAF) were involved with the leishmanicidal activity, and 5) destruction of the parasites did not depend on generation of oxygen or nitrogen radicals, indicating that parasite clearance did not involve the classical pathway of macrophage activation by TNF-alpha, as reported for other Leishmania species.Conclusions/Significance: the present results provide evidence that neutrophils in concert with macrophages play a previously unrecognized leishmanicidal effect on L. (L.) amazonensis. We believe these findings may help to understand the mechanisms involved in innate immunity in cutaneous infection by this Leishmania species.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, São Paulo, BrazilWeb of Scienc

Defining Feasibility and Pilot Studies in Preparation for Randomised Controlled Trials: Development of a Conceptual Framework

We describe a framework for defining pilot and feasibility studies focusing on studies conducted in preparation for a randomised controlled trial. To develop the framework, we undertook a Delphi survey; ran an open meeting at a trial methodology conference; conducted a review of definitions outside the health research context; consulted experts at an international consensus meeting; and reviewed 27 empirical pilot or feasibility studies. We initially adopted mutually exclusive definitions of pilot and feasibility studies. However, some Delphi survey respondents and the majority of open meeting attendees disagreed with the idea of mutually exclusive definitions. Their viewpoint was supported by definitions outside the health research context, the use of the terms ‘pilot’ and ‘feasibility’ in the literature, and participants at the international consensus meeting. In our framework, pilot studies are a subset of feasibility studies, rather than the two being mutually exclusive. A feasibility study asks whether something can be done, should we proceed with it, and if so, how. A pilot study asks the same questions but also has a specific design feature: in a pilot study a future study, or part of a future study, is conducted on a smaller scale. We suggest that to facilitate their identification, these studies should be clearly identified using the terms ‘feasibility’ or ‘pilot’ as appropriate. This should include feasibility studies that are largely qualitative; we found these difficult to identify in electronic searches because researchers rarely used the term ‘feasibility’ in the title or abstract of such studies. Investigators should also report appropriate objectives and methods related to feasibility; and give clear confirmation that their study is in preparation for a future randomised controlled trial designed to assess the effect of an intervention

Áreas de secção transversa do braço: implicações técnicas e aplicações para avaliação da composição corporal e da força dinâmica máxima Area de sección transversa del brazo: implicaciones técnicas y aplicaciones para avaliación de la composición corporal y de la fuerza dinámica máxima Arm cross-section areas: technical implications and applications for body composition and maximal dynamic strength evaluation

As áreas do tecido muscular (A MB) e do anel de gordura do braço (A GB), podem ser estimadas por medidas antropométricas. OBJETIVO: Investigar a validade e o erro intertestador da antropometria para inferência A MB e do A GB. Secundariamente, estudou-se a previsão da força dos membros superiores e tronco através da A MB. MÉTODOS: Foram voluntários para este estudo 40 adultos masculinos jovens (25 ± 6 anos; 72,6 ± 9,4kg), divididos aleatoriamente nos grupos de validade interna (VI, n = 30) e validade externa (VE, n = 10). Determinou-se para VI, através de conceitos geométricos, a área total do braço (A TB), A MB, A GB e área percentual de gordura do braço. O somatório de oito dobras cutâneas (S DC8) foi empregado como índice da adiposidade corporal. A força dos membros superiores e do tronco foi medida através da carga máxima alcançada no exercício supino reto livre (1-RM). As medidas antropométricas foram realizadas por dois avaliadores independentes. Os dados foram tratados por meio da análise de regressão, coeficiente de correlação intraclasse (ICC) e teste t de Student pareado (a < 0,05). RESULTADOS: A variância do S DC8 pode ser explicada em 93% (EPE = 14,6mm) a partir da A GB e do peso corporal. A A MB explicou em 66,1% (EPE = 9kg) a 1-RM. Não se observou diferença significativa, para o grupo VE, entre os valores medidos (84,2 ± 16,2kg) e preditos (78,4 ± 14,2kg) de 1-RM. Observou-se pouca variação entre os avaliadores para A MB (ICC = 0,99), A GB (ICC = 0,96) e A TB (ICC = 0,99). CONCLUSÃO: A antropometria pode ser empregada para inferência da A MB e do A GB, com boa concordância entre avaliadores, para estimativa da adiposidade corporal e da força dos membros superiores e tronco.<br>Las áreas del tejido muscular (A MB) y del de grosor del brazo (A GB), pueden ser estimadas por medidas antropométricas. OBJETIVO: Investigar la validación de el error inter-testeo de la antropometría para inferencia del A MB y del A GB. Secundariamente, se estudió la previsión de la fuerza de los miembros superiores y del tronco a través de la A MB. METODOS: Fueron voluntarios para este estudio 40 jóvenes masculinos (25 ± 6 años; 72,6 ± 9,4 kg), divididos aleatoriamente en los grupos de validación interna (VI, n = 30) y de validación externa (VE, n = 10). Se determinó para VI, a través de conceptos geométricos, el área total del brazo (A TB), A MB, A GB y el área porcentual de gordura de el brazo. La sumatoria de ocho pliegues cutáneos (S DC8) fue empleado como índice de la adiposidad corporal. La fuerza de los miembros superiores y del e tronco fue medida a través de la carga máxima alcanzada del ejercicio supino recto libre (1-RM). Las medidas antropométricas fueron realizadas por dos evaluadores independientes. Los datos fueron tratados por medio del análisis de regresión, con coeficiente de correlación intraclase (ICC) y el test t de Student apareado (a < 0,05). RESULTADOS: La varianza de S DC8 puede ser explicada en un 93% (EPE = 14,6 mm) a partir de A GB y del peso corporal. La A MB se explico en 66,1% (EPE = 9 kg) a 1-RM. No se observó diferencia significativa, para el grupo VE, entre los valores medidos (84,2 ± 16,2 kg) y predecidos (78,4 ± 14,2 kg) de 1-RM. Se observó poca variación entre los evaluadores para A MB (ICC = 0,99), A GB (ICC = 0,96) y A TB (ICC = 0,99). CONCLUSION: La antropometría puede ser empleada para la inferencia de la A MB y del A GB, con buena concordancia entre evaluadores, para estimar la adiposidad coporal y la fuerza de los miembros superiores del tronco.<br>Arm muscular tissue and fat ring areas can be evaluated by anthropometric measures. The objective of this study was to investigate the application of one technique that infers these areas to estimate body adiposity and the maximal strength of upper limbs and trunk, as well as its objectivity. For that, a sample of 40 healthy men (25 ± 6 years; 72.6 ± 9.4 kg) was divided in two groups: VI (n = 30) internal validation and VE (n = 10) external validation. It was determined to VI the muscle area (A MB), fat absolute area (A GB) and fat percentile upper-arm area (A PB) using the values of circumference and triceps skinfold, as well as the sum of seven and eight skinfold thickness (S8DC) and the maximal weight lifted in bench press (1-RM) by two evaluators separately (A and B). In VE only A MB and 1-RM were obtained. Multiple and simple regression analyses and Student t-test were applied (a < 0.05). The variance of S8DC was explained in 93% (EPE = 14.6 mm) from A GB and weight, the A MB explained in 66% (EPE = 9 kg) of the 1-RM variance by itself and there was no significant difference between the maximal weight measured and predicted in VE group. Satisfactory intraclass correlations between the evaluators to A MB (ICC = 0.99), A GB (ICC = 0.96) and A TB (ICC = 0.99) were also found. Therefore it may be concluded that the anthropometric technique that infers muscle and fat upper-arm areas can be used with good agreement between evaluators to estimate body adiposity and upper limbs and trunk strength