Variations in 123I-metaiodobenzylguanidine (MIBG) late heart mediastinal ratios in chronic heart failure: a need for standardisation and validation

BACKGROUND: There is lack of validation and standardisation of acquisition parameters for myocardial (123)I-metaiodobenzylguanidine (MIBG). This lack of standardisation hampers large scale implementation of (123)I-MIBG parameters in the evaluation of patients with chronic heart failure (CHF). METHODS: In a retrospective multi-centre study (123)I-MIBG planar scintigrams obtained on 290 CHF patients (82% male; 58% dilated cardiomyopathy; New York Heart Association [NYHA classification] > I) were reanalysed to determine the late heart-to-mediastinum ratio (H/M). RESULTS: There was a large variation in acquisition parameters. Multivariate forward stepwise regression showed that a significant proportion (31%, p < 0.001) of the variation in late H/M could be explained by a model containing patient-related variables and acquisition parameters. Left ventricular ejection fraction (p < 0.001), type of collimation (p < 0.001), acquisition duration (p = 0.001), NYHA class (p = 0.028) and age (p = 0.034) were independent predictors of late H/M. CONCLUSIONS: Acquisitions parameters are independent contributors to the variation of semi-quantitative measurements of cardiac (123)I-MIBG uptake. Improved standardisation of cardiac (123)I-MIBG imaging parameters would contribute to increased clinical applicability for this procedur

Fast Growth Increases the Selective Advantage of a Mutation Arising Recurrently during Evolution under Metal Limitation

Understanding the evolution of biological systems requires untangling the molecular mechanisms that connect genetic and environmental variations to their physiological consequences. Metal limitation across many environments, ranging from pathogens in the human body to phytoplankton in the oceans, imposes strong selection for improved metal acquisition systems. In this study, we uncovered the genetic and physiological basis of adaptation to metal limitation using experimental populations of Methylobacterium extorquens AM1 evolved in metal-deficient growth media. We identified a transposition mutation arising recurrently in 30 of 32 independent populations that utilized methanol as a carbon source, but not in any of the 8 that utilized only succinate. These parallel insertion events increased expression of a novel transporter system that enhanced cobalt uptake. Such ability ensured the production of vitamin B12, a cobalt-containing cofactor, to sustain two vitamin B12–dependent enzymatic reactions essential to methanol, but not succinate, metabolism. Interestingly, this mutation provided higher selective advantages under genetic backgrounds or incubation temperatures that permit faster growth, indicating growth-rate–dependent epistatic and genotype-by-environment interactions. Our results link beneficial mutations emerging in a metal-limiting environment to their physiological basis in carbon metabolism, suggest that certain molecular features may promote the emergence of parallel mutations, and indicate that the selective advantages of some mutations depend generically upon changes in growth rate that can stem from either genetic or environmental influences

Accelerated life tests analyzed by a piecewise exponential distribution via generalized linear models

Efficient industrial experiments for reliability analysis of manufactured products consist of subjecting the units to accelerated life tests, where for each pre-fixed stress level, the experiment ends after the failure of a certain prefixed proportion of units or a certain test time is reached. This paper estimates the mean life of the units under usual working conditions, based on censored data obtained from units under stress conditions. This problem is approached through a generalized linear model and related inferential techniques, considering the very flexible class of failure distributions, piecewise exponential model, and a log-linear stress-response relationship. The general framework has as particular cases, among others, the power law model, the Arrhenius model, and the generalized Eyring model. A numerical example illustrates the methodology.45461962

Avaliação da eficácia da pomada de própolis em portadores de feridas crônicas Evaluación de la eficacia de la pomada de própolis en portadores de heridas crónicas The effect of propolis cream in healing chronic ulcers

OBJETIVO: Avaliar a evolução de úlceras crônicas utilizando a terapêutica tópica com a própolis. MÉTODOS: Trata-se de um estudo descritivo onde foram identificadas vinte pessoas com feridas crônicas encaminhadas pelas Unidades Básicas de Saúde do Município de Maringá, Paraná. A análise baseou-se na avaliação e no tempo de cicatrização das feridas, realizada por meio do cálculo do Coeficiente de Correlação de Pearson para verificar a relação entre as medidas médias horizontais, verticais e de profundidades, a evolução do processo cicatricial. RESULTADOS: O acompanhamento de 22 úlceras crônicas permitiu observar por meio da análise estatística que a chance de cicatrização de todas as lesões foi de 13,1 semanas. Considerando um seguimento de 20 semanas 74,1% das úlceras lograram cicatrização antes desse período. Quanto à etiologia, as úlceras venosas cicatrizaram em 35% (7) dos pacientes, contrapondo-se às úlceras de pressão cuja cicatrização ocorreu em apenas 10,0% (2) dos pacientes. CONCLUSÃO: Concluiu-se, que a utilização da forma farmacêutica pomada de própolis, de fácil acesso e de baixo custo, foi eficiente na cicatrização de feridas.<br>OBJETIVO: Evaluar la evolución de úlceras cronicas utilizando terapéutica tópica con pomada de própolis. MÉTODOS: Se trata de un estudio descriptivo en el cual fueron identificadas veinte personas con heridas crónicas encaminhadas por las Unidades Básicas de Salud del Municipio de Maringá, Paraná- Brasil. El análisis se basó en la evaluación y en el tiempo de cicatrización de las heridas, realizada por medio del cálculo del Coeficiente de Correlación de Pearson para verificar la relación entre las medias horizontales, verticales y de profundidad, o sea, la evolución del proceso de cicatrización. RESULTADOS: El acompañamiento de 22 úlceras crónicas permitió observar, a través del análisis estadístico, que la probabilidad de cicatrización de todas las lesiones fue de 13,1 semanas. Considerando un seguimiento de 20 semanas el 74,1% de las úlceras lograron la cicatrización antes de ese período. En cuanto a la etiología, las úlceras venosas cicatrizaron en 35% (7) de los pacientes, contraponiéndose a las úlceras de presión cuya cicatrización sucedió en apenas el 10,0% (2) de los pacientes. CONCLUSIÓN: Se concluye, que la utilización de pomada de própolis, de fácil acceso y bajo costo, fue sido eficiente en la cicatrización de heridas.<br>OBJECTIVE: To evaluate the effect of propolis cream in healing chronic. METHODS: This descriptive study used a sample of 20 subjects from a Basic Unit of Health of Maringá City, Paraná, Brazil, who had chronic wounds. Wound healing was measured through progress notes of wound length, width, and depth. Data were analyzed with Pearson's correlation to determine the degree and strength of the relationship between propolis cream treatment and wound healing. RESULTS: The progress notes of 22 chronic ulcers showed that the probability of wound healing was 18.7 weeks. Regarding the study period of 13,1 weeks, the majority of ulcers (74.1%) of ulcers healed completely. Regarding wound etiology, vascular ulcers (35%) healed in 7 patients. And, pressure ulcers (10%) healed in patients. CONCLUSION: The use of propolis cream, which is widely accessible and inexpensive, was effective in healing chronic wounds

Testes de função pulmonar e mortalidade após o transplante de células-tronco hematopoiéticas Hematopoietic stem cell transplantation: pulmonary function tests and post-transplant mortality

OBJETIVO: Verificar se os resultados dos testes de função pulmonar realizados em pacientes submetidos a transplante de células-tronco hematopoiéticas (TCTH) estão associados com a mortalidade após o procedimento. MÉTODOS: Estudo prospectivo no qual foram incluídos pacientes maiores de 15 anos submetidos a TCTH alogênico, entre janeiro de 2007 e março de 2008, no Hospital das Clínicas da Universidade Federal de Minas Gerais, em Belo Horizonte (MG), e que realizaram espirometria, medida de volumes pulmonares e medida de DLCO antes do TCTH. Os testes foram repetidos seis meses, um ano e dois anos após TCTH. Para a análise de sobrevida, foram utilizados o método de Kaplan-Meier e testes de log-rank bicaudal. O risco relativo (RR) e IC95% foram calculados por meio do ajuste do modelo de riscos proporcionais de Cox. O modelo de regressão de Cox foi utilizado na análise multivariada. RESULTADOS: Dos 54 pacientes incluídos, 40 (74,1%) apresentaram resultados normais de função pulmonar antes do TCTH. Ocorreram 23 óbitos (42,6%) em dois anos após o TCTH, sendo que 19 aconteceram antes de 100 dias. Dos 23 óbitos, 11 (47,8%) foram por septicemia e 10 (43,4%) por insuficiência respiratória aguda associada à septicemia. As únicas variáveis que mostraram associação significativa com mortalidade após TCTH foram alteração na espirometria antes do TCTH (RR = 3,2; p = 0,016) e doador não aparentado (RR = 9,0; p < 0,001). CONCLUSÕES:A realização da espirometria antes do TCTH fornece valores basais para comparações futuras. Alterações nesses resultados indicam um maior risco de mortalidade após o TCTH, embora esses não contraindicam o procedimento.<br>OBJECTIVE:To determine whether the results of pulmonary function tests carried out in patients subsequently submitted to hematopoietic stem cell transplantation (HSCT) are associated with post-HSCT mortality. METHODS: This was a prospective study involving patients older than 15 years of age who were submitted to allogenic HSCT between January of 2007 and March of 2008 at the Hospital das Clínicas da Universidade Federal de Minas Gerais, located in the city of Belo Horizonte, Brazil. Prior to HSCT, all of the patients underwent spirometry, determination of lung volumes, and determination of DLCO. Those same tests were repeated six months, one year, and two years after HSCT. Kaplan-Meier curves and two-tailed log-rank tests were used for survival analysis. The relative risk (RR) and 95% CI were calculated using the Cox proportional hazards model. The Cox regression model was used in the multivariate analysis. RESULTS:The pre-HSCT pulmonary function results were normal in 40 (74.1%) of the 54 patients evaluated, 19 (35.2%) of whom died within the first 100 days after HSCT. By the end of the two-year follow-up period, 23 patients (42.6%) had died, the most common causes of death being septicemia, observed in 11 (47.8%), and septicemia-related respiratory insufficiency, observed in 10 (43.4%). The only variables significantly associated with post-HSCT mortality were alterations in spirometry results prior to HSCT (RR = 3.2; p = 0.016) and unrelated donor (RR = 9.0; p < 0.001). CONCLUSIONS: Performing spirometry prior to HSCT provides baseline values for future comparisons. Although alterations in spirometry results reveal a higher risk of post-HSCT mortality, such alterations do not contraindicate the procedure