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Las afecciones en la piel de las manos están dentro de los mayores problemas a los que se enfrenta el personal de enfermería, debido a su continua exposición a factores desencadenantes, afectando de esta manera la calidad del proceso de atención. El objetivo de esta investigación fue fomentar estrategias que permitan disminuir afecciones ocupacionales en la piel de las manos del personal de enfermería. Se realizó un estudio cuantitativo, observacional, descriptivo, no experimental, basado en la recolección de datos, a través de un instrumento validado mediante la revisión por expertos en salud e investigación científica y la aplicación de procesos estadísticos. La población se constituyó por 80 profesionales de enfermería, pertenecientes a establecimientos de salud públicos y privados de la ciudad de Ambato. Los resultados obtenidos fueron que el 100% ha tenido afecciones en la piel de manos, donde los más afectados estuvieron dentro del rango de 11 a 15 años de vida profesional. Los factores de riesgo prevalentes fueron: la exposición a la humedad, uso de soluciones antisépticas y lavado de manos mayor a 16 veces (63,7 %) durante la jornada laboral. El 70% refirió no tener alergia al látex y el 30% solo cuando su uso fue prolongado.Los principales signos y síntomas fueron: eritema, prurito y ardor. Se evidenció que, dentro de los establecimientos de salud no existen estrategias de prevención para dichas afecciones, motivo por el cual se apoyó de manera unánime la creación e implementación, determinando así la importancia de esta investigación.

El espíritu del Tratado de Paz y Amistad de 1929 entre Chile y Perú fue una alianza focalizada establecida para sellar una defensa respecto de las pretensiones bolivianas para anexionarse Tacna y Arica. Este espíritu se refleja en la partición de los territorios disputados, así como en el Artículo 3 del Protocolo Complementario, que establece, de forma críptica, que ni Chile ni Perú podrían ceder esos territorios a Bolivia. La explicación está en los 45 años de conflictos entre Chile y Perú debido a la pretensión boliviana de anexionarse los territorios peruanos que ocupaba Chile tras la Guerra del Pacífico. Sin embargo, tras la cesión de Arica, el fundacional reclamo de Bolivia por anexionarse este puerto se dirigió contra Chile. Tras el Tratado de 1929, la diplomacia boliviana trabajó por romper esta alianza, cuestión que se logró en 1975 con los acuerdos de Charaña.

Background St. Louis encephalitis virus (SLEV) is endemic and autochthonous on the American continent. Culex pipiens quinquefasciatus is a vector of SLEV; however, Culex interfor and Culex saltanensis have also been found to be naturally infected with SLEV. The aim of this study was to determine the vector competence of C. interfor and C. saltanensis for SLEV from Argentina compared with C. p. quinquefasciatus. Methods Female of the Culex species were orally infected by feeding on viraemic chicks that had been inoculated with SLEV. Abdomens, legs and saliva blood-fed mosquitoes were analysed by viral plaque assay. Results Mosquitoes were susceptible to orally acquired infection, dissemination and transmission of SLEV in the saliva. Conclusions Our results demonstrate that C. saltanensis and C. interfor are susceptible to SLEV and competent for its transmission.

En mayo del 2019, se modificó la metodología de la Encuesta de Confianza de los Consumidores, cambiando de la telefonía fija a la móvil, por lo que las cuatro encuestas previas se realizaron con ambos métodos para investigar el efecto en el Índice de Confianza del Consumidor (ICC), entre otras estadísticas de interés. En tres de las encuestas no se encontró evidencia de diferencias en las magnitudes del ICC. Además, la disminución de la confianza que registró el índice de mayo a noviembre se dio con ambos tipos de encuesta (-16,8 puntos con la fija y -16,0 puntos con la móvil) y el aumento de la confianza en las encuestas siguientes fue similar (6,6 y 6,4, respectivamente). Se concluye que, usando ambas metodologías, la magnitud de las estimaciones del ICC, y de otros indicadores de interés, no mostraron diferencias estadísticamente significativas en tres de las cuatro encuestas y que también reproducen la misma tendencia.

espanolEste articulo analiza el contenido de la Nota 5-4-M/147, del 23 de mayo de 1986 de la Embajada del Peru a la Cancilleria Chilena, conocida como el “Memorandum Bakula”. El documento es importante pues se trata de la primera comunicacion diplomatica en la que se planteo la inexistencia de un tratado especifico de limites maritimos. El objetivo de este trabajo fue examinar los parrafos del memorandum que aluden a la discusion chilena y peruana sobre la naturaleza de la Declaracion de Santiago de 1952 y el Convenio sobre Zona Especial Fronteriza Maritima de 1954. Aunque el objetivo primordial del Memorandum Bakula fue el inicio de una negociacion, la falta de respuesta por parte de Chile lo transformo en la piedra angular de la demanda internacional de Peru ante La Haya. portuguesEste artigo analisa o conteudo da Nota 5-4-M/147, de 23 de maio de 1986 da Embaixada do Peru a Chancelaria Chilena, conhecida como o “Memorandum Bakula”. Esse documento e importante, pois se trata da primeira comunicacao diplomatica na qual foi apresentada a inexistencia de um tratado especifico de limites maritimos. O objetivo deste trabalho e examinar os paragrafos do memorando que se referem a discussao chilena e peruana sobre a natureza da Declaracao de Santiago de 1952 e o Convenio sobre a Zona Especial Fronteirica Maritima de 1954. Embora o objetivo primordial do Memorandum Bakula tenha sido o inicio de uma negociacao, a falta de resposta do Chile o transformou na pedra angular da demanda internacional do Peru ante La Haya. EnglishThis article analyzes the contents of Note 5-4-M/147 dated May 23, 1986, sent by the Embassy of Peru to the Chilean Chancellery, known as the “Bakula Memorandum.” The document is significant because it is the first diplomatic communication that raises the absence of a specific treaty on maritime boundaries. The aim is to examine those paragraphs of the memorandum that allude to the Chilean-Peruvian debate on the nature of the 1952 Declaration of Santiago and the 1954 Special Maritime Frontier Zone Agreement. Although the primary objective of the Bakula Memorandum was to start negotiations, Chile’s failure to reply made it the cornerstone of Peru’s international lawsuit at The Hague.

A systematic review and meta-analysis were carried out to investigate the effect of ultrasound-assisted wound (UAW) debridement in patients with diabetic foot ulcers (DFUs). All selected studies were evaluated using the Cochrane risk of bias tool to assess the risk of bias for randomized controlled trials. PubMed and Web of Science were searched in October 2021 to find randomized clinical trials (RCT) assessing the effect of UAW debridement on DFUs. RevMan v5.4. was used to analyze the data with the Mantel–Haenszel method for dichotomous outcomes. A total of 8 RCT met our inclusion criteria, with 263 participants. Concerning the healing rate comparing UAW versus the control group, a meta-analysis estimated the pooled OR at 2.22 (95% CI 0.96–5.11, p = 0.06), favoring UAW debridement, with low heterogeneity (x2 = 7.47, df = 5, p = 0.19, I2 = 33%). Time to healing was similar in both groups: UAW group (14.25 ± 10.10 weeks) versus the control group (13.38 ± 1.99 weeks, p = 0.87). Wound area reduction was greater in the UAW debridement group (74.58% ± 19.21%) than in the control group (56.86% ± 25.09%), although no significant differences were observed between them (p = 0.24). UAW debridement showed higher healing rates, a greater percentage of wound area reduction, and similar healing times when compared with placebo (sham device) and standard of care in patients with DFUs, although no statistically significant differences were observed between groups.

La siguiente investigación tiene como propósito presentar un estudio de la oferta académica y la demanda laboral para la carrera de Administración de Negocios en Costa Rica. ¿Ofrecen las universidades a sus estudiantes las herramientas necesarias para satisfacer las demandas del mercado? Como metodología, se creó un índice que vincula la demanda laboral con la oferta académica, por medio de una nota que determina la compatibilidad de cada universidad y las posiciona. Para analizar la oferta académica, se tomaron todos los planes de estudio de las carreras acreditadas ante el Sinaes y se analizaron y dividieron en dos áreas: básica y complementaria. Con respecto a la demanda, se realizó un censo basado en el top cuarenta de las mejores empresas para trabajar, según Great Place to Work 2018, en el cual se preguntaba sobre las aptitudes y actitudes que buscan al reclutar. El índice arrojó notas entre 30.48 hasta 56.68, posicionando a la Universidad de Costa Rica en el cuarto lugar. The following research aims to present a study of academic supply and labor demand for the Business Administration career in Costa Rica. Do universities offer their students the necessary tools to meet market demands? As a methodology, an index was created that links the labor demand with the academic offer, by means of a note that determines the compatibility of each university and positions them. To analyze the academic offer, all the curricula of the careers were taken accredited to Sinaes, they were analyzed and divided into two areas: basic and complementary. With respect to the demand, a census was made based on the top forty companies according to Great Place to Work 2018, where they asked about the skills and attitudes they seek when recruiting. The index threw notes between 30.48 and 56.68, placing the University of Costa Rica in fourth place.

Este trabajo examina el uso de acuerdos bilaterales (contractuales y convencionales) para la provisión de prestaciones clínicas a los sistemas públicos de salud. La gestión contractual de la sanidad pública es un proceso común en las reformas sanitarias impulsadas desde la década de 1980, que pretendían transformar los sistemas sanitarios en mercados de servicios clínicos. Para tales propósitos, los contratos y convenios son los instrumentos jurídicos que utiliza el sistema público chileno para requerir las atenciones del sector privado. Sin embargo, la falta de un tratamiento sistemático de los contratos del Estado por parte del legislador provocó una discusión que terminó reduciendo todos los acuerdos a compras de servicios.

El artículo analiza los contratos entre el sistema público de salud y proveedores privados. En específico; se estudia la participación del sector privado en el sistema público de salud y cómo se acude a mecanismos contractuales para incorporarlos en ellos; una tendencia que a nivel internacional cobra mayor fuerza. En el diseño contractual se presentan dos grandes tendencias. La primera de ellas se crear condiciones de mercado en la prestación de las atenciones de salud; en la que el privado compite con entes públicos por los mismos recursos. La segunda tendencia es plantear la participación de prestadores privados como colaboradores del sector público; caso en el que los contratos serán mecanismos articuladores de una red asistencial. El artículo muestra que la segunda tendencia es la que se aplica en el caso chileno. Se argumenta que los convenios realizados por los servicios de salud y sus entes dependientes; han tendido a crear una suerte de cuasimercado de prestaciones de salud. A la vez; se analiza cómo los contratos celebrados por Fonasa; que han articulado una red público privada con resultados positivos.

Durante una visita a la Isla María Cleofas, en el archipiélago de las Islas Marías, ubicado en la desembocadura del Golfo de California, México, se recolectaron tres especímenes del ciempiés tigre Scolopendra polymorpha Wood, 1861 (ejemplares de longitud: 73 mm, 91 mm y 125 mm). Hasta donde sabemos, estos ejemplares representan el primer registro confirmado de la especie para la Isla María Cleofas. Probablemente, el ciempiés tigre y la fauna de ciempiés en general de la Isla María Cleofas provienen de áreas continentales adyacentes.

Pectins are a type of soluble fiber present in natural and processed foods. Evidence regarding the effect of esterification degree of pectins on iron absorption in humans is scarce. In the present study, the effect of pectins with different degrees of esterification on non-heme iron absorption in women was evaluated. A controlled experimental study was conducted with block design, involving 13 apparently healthy, adult women. Each subject received 5 mg Fe (FeSO4) without pectin (control) or accompanied by 5 g citrus pectin, two with a low degree of esterification (27 and 36%), and one with a high degree of esterification (67 to 73%), each on different days. Each day, the 5 mg Fe doses were marked with radioactive 59Fe or 55Fe. Radioactivity incorporated into erythrocytes was determined in blood samples 14 days after the marked Fe doses were consumed. On days 18 and 36 of study, 30 and 20 mL blood samples were obtained, respectively, and blood sample radioactivity incorporated into erythrocytes was determined. Body iron status was determined from blood taken on day 18. Whole body blood volume was estimated for calculate iron bioavailability; it was assumed that 80% of absorbed radioactivity was incorporated into the Hb. All women participants signed an informed consent of participation at baseline. Iron bioavailability (mean geometric ±1 SD) alone (control) was 18.2% (12.3–27.1%), iron + pectin27 was 17.2% (10.2–29.2%), iron + pectin36 was 15.3% (9.5–24.6%), and iron + pectin67 was 19.5% (10.0–38.0%). No statistically significant differences between iron bioavailability (repeated measures ANOVA, p = 0.22) were observed. Pectin esterification degree does not influence the bioavailability of non-heme iron in women.

Introduccion: El tabaco es la primera causa de morbimortalidad prevenible en el mundo. En Chile la prevalencia de consumo es 40,6%, la mayor a nivel continental. El consejo breve o consejeria breve (CB) es una intervencion simple, efectiva y de bajo costo para el cese de consumo de tabaco, que Atencion Primaria en Salud (APS) ha demostrado disminuir la prevalencia de tabaquismo. Existe escasa informacion sobre la utilizacion de CB en APS en Chile. Metodos: Estudio transversal de metodologia cuantitativa. Se encuesto a 604 pacientes pertenecientes a 2 centros APS de Santiago, tras haber recibido atencion clinica. Los datos fueron analizados con SPSS 21 y calculadora web Graph Pad. Resultados: La prevalencia de tabaquismo entre los encuestados fue 32,5%, de ellos el 78,9% reporto deseo de dejar de fumar. Al 43,7% de los encuestados se le pregunto respecto a consumo de tabaco en la atencion reciente, y del total de fumadores a 37,1% se les aconsejo dejar de fumar. Los pacientes fumadores calificaron la recepcion de CB como “indeferente”, “agradable” o “muy agradable” en un 94,9% y en un 90,5% entre aquellos que no desean dejar de fumar. Conclusiones: El tabaquismo es un problema escasamente abordado en las atenciones clinicas APS, lo que contrasta con la alta prevalencia de consumo nacional y de los pacientes consultantes. La mayoria de los fumadores desea dejar de fumar y la minoria considera “desagradable” o “muy desagradable” ser aconsejada para cesar el consumo, aun en aquellos fumadores que no quieren dejar de fumar.

Forty-five women (35-45 year) were randomly assigned to three iron (Fe) absorption sub-studies, which measured the effects of dietary animal proteins on the absorption of heme Fe. Study 1 was focused on heme, red blood cell concentrate (RBCC), hemoglobin (Hb), RBCC+beef meat; study 2 on heme, heme+fish, chicken, and beef; and study 3 on heme and heme+purified animal protein (casein, collagen, albumin). Study 1: the bioavailability of heme Fe from Hb was similar to heme only (∼13.0%). RBCC (25.0%) and RBCC+beef (21.3%) were found to be increased 2- and 1.6-fold, respectively, when compared with heme alone (p

In 1974, Eisenthal and Cornish-Bowden published the direct linear plot method, which used the median to estimate the Vmax and Km from a set of initial rates as a function of substrate concentrations. The robustness of this non-parametric method was clearly demonstrated by comparing it with the least-squares method. The authors commented that the method cannot readily be generalized to equations of more than two parameters. Unfortunately, this comment has been misread by other authors. Comments such as "this method cannot be extended directly to equations with more than two parameters" were found in some publications. In addition, recently, the most drastic comment was published: "this method cannot be applied for the analysis of substrate inhibition." Given all of these presumptions, we have been motivated to publish a demonstration of the contrary: the median method can be applied to more than two-parameter equations, using as an example, the substrate uncompetitive inhibition equation. A computer algorithm was written to evaluate the effect of simulated experimental error of the initial rates on the estimation of Vmax, Km and KS. The error was assigned to different points of the experimental design. Four different KS/Km ratios were analyzed with the values 10, 100, 1000 and 10,000. The results indicated that the least-squares method was slightly better than the median method in terms of accuracy and variance. However, the presence of outliers affected the estimation of kinetic constants using the least-squares method more severely than the median method. The estimation of KS using the median method to estimate 1/KS was much better than the direct estimation of KS, causing a negative effect of non-linearity of KS in the kinetic equation. Considering that the median method is free from the assumptions of the least-squares method and the arbitrary assumptions implicit in the linearization methods to estimate the kinetic constants Vmax, Km and KS from the substrate uncompetitive inhibition equation, the median method is highly superior to all published methods, including the non-linear regression by least squares. We concluded that the median method can be applied to the substrate uncompetitive inhibition equation and other equations with more than two parameters. In addition, as we can project, the median method is the most reliable and robust method for the estimation of kinetic parameters from enzyme kinetic models.

Thoracolumbar burst fractures account for up to 17% of major spinal fractures. Both conservative and operative treatments are widely used in clinical practice to manage thoracolumbar burst fractures. Previous studies showed good functional results with both treatments, but surgical approach has been associated with higher cost and risks of causing unnecessary adverse effects. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified 14 systematic reviews including 25 randomized trials. We combined the evidence using meta-analysis and generated a summary of findings table following the GRADE approach. We concluded that operative treatment may decrease the risk of neurologic impairment, but in turn, could increase the risk of general complications. It is unclear whether there are differences in pain reduction, improvement in function and quality of life, need for subsequent surgery or radiographic progression of kyphosis in both groups.Las fracturas toracolumbares tipo burst representan hasta el 17% de las fracturas de columna.Se ha planteado tanto el tratamiento conservador como el quirúrgico para este tipo de fracturas, observando buenos resultados funcionales con ambos, pero con un mayor costo y riesgo de producir efectos adversos con la cirugía. Utilizando la base de datos Epistemonikos, la cual es mantenida mediante búsquedas en 30 bases de datos, identificamos seis revisiones sistemáticas que en conjunto incluyen cuatro estudios aleatorizados. Realizamos un metanálisis y tablas de resumen de los resultados utilizando el método GRADE. Concluimos que el tratamiento quirúrgico podría disminuir el riesgo de deterioro neurológico pero con un mayor riesgo de complicaciones generales. Concluimos que no está claro si existen diferencias en dolor, funcionalidad, calidad de vida, necesidad de reintervención o progresión radiográfica de la cifosis entre el tratamiento conservador y el quirúrgico.

In the human gastrointestinal tract, trypsin and mucin may affect the absorption of heme iron. However, these interactions have not been well-established. We determined the effect of trypsin and mucin on heme iron absorption in humans. Design: Twenty-eight apparently healthy females participated in two studies (14 per study). Study A evaluated the effect of trypsin on iron bioavailability. Subjects ingested 100 mg trypsin and 1.7 g mucin on 5 mg heme iron bioavailability on days 1, 2, 14, and 15, respectively. In study B, which assessed the effect of mucin on heme iron bioavailability, the subjects ingested hemin, hemin plus mucin, hemoglobin (Hb), and Hb plus mucin, on days 1, 2, 14, and 15, respectively. Results: In study A, the geometric means ± 1 SD of heme iron absorption were 5.1 % (3.1–8.3), 2.9 % (1.6–5.1), 7.3 % (4.1–13.1), and 6 % (2.7–13) for hemin, hemin plus trypsin, Hb plus trypsin, and Hb plus mucin plus trypsin, respectively. In study B, the geometric means ± 1 SD of heme iron absorption were 16.4 % (10.5–25.7), 13.1 % (9.0–18.9), 13.7 % (9.0–20.7), and 11.8 % (7.6–18.3) for hemin, hemin plus mucin, Hb, and Hb plus mucin, respectively. The ratio increased when Hb plus trypsin was ingested and decreased when hemin plus trypsin was ingested. There were no differences in other ratios with respect to the ratio on day 1 (P

There are several nonsurgical alternatives to treat radicular pain in degenerative lumbar spinal stenosis. Epidural steroid injections have been used for several decades, but the different studies have shown variable effects. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified nine systematic reviews including seven pertinent randomized controlled trials. We concluded epidural steroid injection probably leads to little or no effect on reducing radicular pain of spinal stenosis.Existe una variada cantidad de alternativas no quirúrgicas para tratar el dolor radicular producido por la raquiestenosis lumbar degenerativa. Los corticoides epidurales se utilizan desde hace varias décadas, sin embargo la eficacia reportada en la literatura es muy variable. Utilizando la base de datos Epistemonikos, la cual es mantenida mediante búsquedas en 30 bases de datos, identificamos nueve revisiones sistemáticas que en conjunto incluyen siete estudios aleatorizados. Realizamos un metanálisis y tablas de resumen de los resultados utilizando el método GRADE. Concluimos que la inyección de corticoides epidurales probablemente tiene poco o nulo efecto en reducir el dolor radicular por estenorraquis.

St. Louis encephalitis virus is a reemerging human pathogen widely distributed in the American continent. Although not fully understood, SLEV transmission network may involve Culex quinquefasciatus mosquito as vectors and Columbidae species as hosts. To calculate infections rates, we inoculated Cx. quinquefasciatus mosquitoes from Córdoba, Argentina by feeding them on viremic chicks. Results and Discussion: We observed differences in infection rate among viral strains. The viral strain 78V-6507 produced the highest rate (90.8%). After re-feeding on susceptible chicks, mosquitoes were able to transmit the virus. Our findings suggest Cx. quinquefasciatus populations are not only susceptible but also able to transmit different SLEV strains. Fil: Diaz, Luis Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina. Universidad Nacional de Córdoba. Facultad de Medicina. Instituto de Virología “Dr. J. M. Vanella”; Argentina Fil: Flores, Fernando Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Córdoba. Facultad de Medicina. Instituto de Virología “Dr. J. M. Vanella”; Argentina. Ministerio de Salud. Instituto Nacional de Medicina Tropical; Argentina Fil: Beranek, Mauricio Daniel. Universidad Nacional de Córdoba. Facultad de Medicina. Instituto de Virología “Dr. J. M. Vanella”; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Rivarola, María Elisa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Córdoba. Facultad de Medicina. Instituto de Virología “Dr. J. M. Vanella”; Argentina Fil: Almiron, Walter Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Investigaciones Entomológicas de Córdoba; Argentina Fil: Contigiani de Minio, Marta Silvia. Universidad Nacional de Córdoba. Facultad de Medicina. Instituto de Virología “Dr. J. M. Vanella”; Argentina

It has been suggested that calcium inhibits the absorption of dietary iron by directly affecting enterocytes. However, it is not clear if this effect is due to a decreased uptake of iron or its efflux from enterocytes. We studied the effect of calcium on the uptake, efflux, and net absorption of non-heme iron using the intestinal-like epithelial cell line Caco-2 as an in vitro model. Caco-2 cells were incubated for 60 min in a buffer supplemented with non-heme iron (as sulfate) and calcium to achieve calcium to iron molar ratios ranging from 50:1 to 1,000:1. The uptake, efflux, and net absorption of non-heme iron were calculated by following a radioisotope tracer of (55)Fe that had been added to the buffer. Administration of calcium and iron at molar ratios between 500 and 1,000:1 increased the uptake of non-heme iron and decreased efflux. Calcium did not have an effect on the net absorption of non-heme iron. At typical supplementary doses for calcium and non-heme iron, calcium may not have an effect on the absorption of non-heme iron. The effect of higher calcium to iron molar ratios on the efflux of non-heme iron may be large enough to explain results from human studies.

A mathematical model that describes the heterogeneous reaction-diffusion process involved in penicillin G hydrolysis in a batch reactor with immobilized penicillin G acylase is presented. The reaction system includes the bulk liquid phase containing the dissolved substrate (and products) and the solid biocatalyst phase represented by glyoxyl-agarose spherical porous particles carrying the enzyme. The equations consider reaction and diffusion components that are presented in dimensionless form. This is a complex reaction system in which both products of reaction and the substrate itself are inhibitors. The simulation of a batch reactor performance with immobilized penicillin G acylase is presented and discussed for the internal diffusional restrictions impact on effectiveness and productivity. Increasing internal diffusional restrictions, through increasing catalyst particle size and enzyme loading, causes impaired catalyst efficiency expressed in a reduction of effectiveness factor and specific productivity. High penicillin G initial concentrations decrease the impact of internal diffusional restrictions by increasing the mass transfer towards porous catalyst until product inhibition becomes significant over approximately 50 mM of initial penicillin G, where a drop in conversion rate and a maximum in specific productivity are then obtained. Results highlight the relevance of considering internal diffusional restrictions, reactor performance, and productivity analysis for proper catalyst and reactor design.

A mathematical model is presented for the kinetically controlled synthesis of cephalexin that describes the heterogeneous reaction-diffusion process involved in a batch reactor with glyoxyl-agarose immobilized penicillin acylase. The model is based on equations considering reaction and diffusion components. Reaction kinetics was considered according to the mechanism proposed by Schroën, while diffusion of the reacting species was described according to Fick's law. Intrinsic kinetic and diffusion parameters were experimentally determined in independent experiments. It was found that from the four kinetic constants, the one corresponding to the acyl-enzyme complex hydrolysis step had the greatest value, as previously reported by other authors. The effective diffusion coefficients of all substances were about 5×10(-10)m(2)/s, being 10% lower than free diffusion coefficients and therefore agreed with the highly porous structure of glyoxyl-agarose particles. Simulations made from the reaction-diffusion model equations were used to evaluate and analyze the impact of internal diffusional restrictions in function of catalyst enzyme loading and particle size. Increasing internal diffusional restrictions decreases the Cex synthesis/hydrolysis ratio, the conversion yield and the specific productivity. A nonlinear relationship between catalyst enzyme loading and specific productivity of Cex was obtained with the implication that an increase in catalyst enzyme loading will not increase the volumetric productivity by the same magnitude as it occurs with the free enzyme. Optimization of catalyst and reactor design should be done considering catalyst enzyme loading and particle size as the most important variables. The approach presented can be extended to other processes catalyzed by immobilized enzymes.

It is known that heme iron and inorganic iron are absorbed differently. Heme iron is found in the diet mainly in the form of hemoglobin and myoglobin. The mechanism of iron absorption remains uncertain. This study focused on the heme iron uptake by Caco-2 cells from a hemoglobin digest and its response to different iron concentrations. We studied the intracellular Fe concentration and the effect of time, K+ depletion, and cytosol acidification on apical uptake and transepithelial transport in cells incubated with different heme Fe concentrations. Cells incubated with hemoglobin-digest showed a lower intracellular Fe concentration than cells grown with inorganic Fe. However, uptake and transepithelial transport of Fe was higher in cells incubated with heme Fe. Heme Fe uptake had a low Vmax and Km as compared to inorganic Fe uptake and did not compete with non-heme Fe uptake. Heme Fe uptake was inhibited in cells exposed to K+ depletion or cytosol acidification. Heme oxygenase 1 expression increased and DMT1 expression decreased with higher heme Fe concentrations in the media. The uptake of heme iron is a saturable and temperature-dependent process and, therefore, could occur through a mechanism involving both a receptor and the endocytic pathway.

Upper gastrointestinal bleeding constitutes a medical-surgical emergency given its important associated morbidity and mortality. The antifibrinolytic tranexamic acid might help stopping bleeding, but controversy remains about its role in this setting. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified five systematic reviews including eight randomized trials. We combined the evidence using meta-analysis and generated a summary of findings table following the GRADE approach. We concluded tranexamic acid probably decreases rebleeding and mortality, without increasing thromboembolic adverse effects in patients with upper gastrointestinal bleeding.La hemorragia digestiva alta corresponde a una emergencia médico-quirúrgica debido a la alta morbilidad y mortalidad que conlleva. El ácido tranexámico, un antifibrinolítico, podría ayudar a lograr un control precoz del sangrado, sin embargo existe controversia sobre su real utilidad. Utilizando la base de datos Epistemonikos, la cual es mantenida mediante búsquedas en 30 bases de datos, identificamos cinco revisiones sistemáticas que en conjunto incluyen ocho estudios aleatorizados. Realizamos un metanálisis y tablas de resumen de los resultados utilizando el método GRADE. Concluimos que el ácido tranexámico probablemente disminuye el resangrado y la mortalidad, y no aumenta los efectos adversos tromboembólicos en pacientes con hemorragia digestiva alta.

Heme oxygenase-1 is a microsomal enzyme that, when induced by stress, protects the cells from oxidative injury. Heme oxygenase-1 participates in the cleavage of the heme ring producing biliverdin, CO and ferrous Fe. The released Fe becomes part of intracellular Fe pool and can be stored in ferritin or released by an iron exporter. The mechanism by which heme enters cells is not completely understood, although it had been suggested that it might be internalized by an endocytosis process. In this study, we expressed a full-length Heme oxygenase-1 cDNA in Caco-2 cells and measured intracellular iron content, heme-iron uptake and transport and immunolocalization of heme oxygenase-1 in these cells. We found that heme oxygenase-1 expressing cells showed increased apical heme iron uptake and transepithelial transport when compared to control cells. These results suggested that heme oxygenase-1 mediates heme iron influx and efflux in intestinal cells. Key terms: iron, heme, heme oxygenase, Caco-2 cells

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