Role of dietary antioxidant (-)-epicatechin in the development of ß-lactoglobulin fibrils.

Under specific physico-chemical conditions ß-lactoglobulin is seen to form fibrils structurally highly similar to those that are formed by the amyloid-like proteins associated with neurodegenerative disorders, such as Alzheimer and Parkinson diseases. In the present study we provide insights on the possible role that the dietary flavonoid (-)-epicatechin plays on ß-lactoglobulin fibril formation. Fibril formation is induced by keeping ß-lactoglobulin solutions at pH2.0 and at a temperature of 80°C for 24h. Atomic Force Microscopy measurements suggest that, by adding (-)-epicatechin in the solution, fibrils density is visibly lowered. This last observation is confirmed by Fluorescence Correlation Spectroscopy experiments. With the use of Fourier Transform IR spectroscopy we monitored the relative abundances of the secondary structures components during the heating process. We observed that in the presence of (-)-epicatechin the spectral-weight exchange between different secondary structures is partially inhibited. Molecular Dynamics simulations have been able to provide an atomistic explanation of this experimental observation, showing that (-)-epicatechin interacts with ß-lactoglobulin mainly via the residues that, normally in the absence of (-)-epicatechin, are involved in ß-sheet formation. Unveiling this molecular mechanism is an important step in the process of identifying suitable molecules apt at finely tuning fibril formation like it is desirable to do in food industry applications.

Relationship between digestibility and secondary structure of raw and thermally treated legume proteins: a Fourier transform infrared (FT-IR) spectroscopic study.

The secondary structure of proteins in legumes, cereals, milk products and chicken meat was studied by diffuse reflectance infrared spectroscopy in the region of the amide I band. Major secondary structure components ( ß-sheets, random coil, α-helix, turns), together with the low- and high-frequency side contributions, were resolved and related to the in vitro digestibility behaviour of the different foods. A strong inverse correlation between the relative spectral weights of the ß-sheet structures and in vitro protein digestibility values was measured. Structural modifications in legume proteins induced by autoclaving were monitored by the changes in the amide I spectra. The results indicate that the ß-sheet structures of raw legume proteins and the intermolecular ß-sheet aggregates, arising upon heating, are primary factors in adversely affecting the digestibility.

Secondary structure of food proteins by Fourier transform spectroscopy in the mid-infrared region.

Fourier transform spectroscopy in the mid-infrared (400-5,000 cm(-1)) (FT-IR) is being recognized as a powerful tool for analyzing chemical composition of food, with special concern to molecular architecture of food proteins. Unlike other spectroscopic techniques, it provides high-quality spectra with very small amount of protein, in various environments irrespective of the molecular mass. The fraction of peptide bonds in alpha-helical, beta-pleated sheet, turns and aperiodic conformations can be accurately estimated by analysis of the amide I band (1,600-1,700 cm(-1)) in the mid-IR region. In addition, FT-IR measurement of secondary structure highlights the mechanism of protein aggregation and stability, making this technique of strategic importance in the food proteomic field. Examples of applications of FT-IR spectroscopy in the study of structural features of food proteins critical of nutritional and technological performance are discussed.

Human insulin fibrillogenesis in the presence of epigallocatechin gallate and melatonin: Structural insights from a biophysical approach.

Fibrillogenesis of monomeric human insulin in the presence or absence of (-)-epigallocatechin-3-gallate and melatonin was here investigated using a multi-technique approach. Results from Raman and Infrared spectroscopy pointed out that a high content of intermolecular ß-sheet aggregates is formed after long-term incubation. However, near UV experiments, Dynamic Light Scattering, Thioflavin-T fluorescence measurements and Atomic Force Microscopy revealed that the kinetics from native-to-fibrillar state of insulin is hampered only in the presence of (-)-epigallocatechin-3-gallate. Molecular dynamic simulations indicated that this compound binds near the B11-B18 protein segment, where hydrophobic residues responsible for the beginning of cooperative aggregation are located. Such a preferential binding region is not recognized by melatonin, a highly mobile molecule, which indeed does not affect fibril formation. The results of the present study demonstrate that (-)-epigallocatechin-3-gallate interferes with the insulin nucleation phase, giving rise to amorphous aggregates in the early stages of the aggregation process.

Rol de enfermería en el área COVID en un hospital pediátrico de alta complejidad / The role of nurses in the COVID area in a pediatric tertiary-care hospital

Introducción: la pandemia por SARS-CoV-2 planteó un desafío para todo el equipo de salud. Fue necesario analizar y pensar en este contexto el rol de enfermería en la atención y cuidados del paciente y su familia. Los procesos asistenciales debieron adaptarse a nuevas y diversas situaciones que generaron la atención de pacientes en su mayoría con comorbilidades asociadas. El objetivo del trabajo fue describir el rol de enfermería y la implementación de diversos protocolos y procesos de atención de pacientes en salas de internación pediátrica del área COVID de un hospital de alta complejidad. Material y métodos: se realizó un estudio retrospectivo y descriptivo sobre el personal de enfermería que participó en la atención de casos sospechosos o confirmados de COVID-19 durante la pandemia y los protocolos implementados para los cuidados de enfermería. Resultados: solo el 52.5% (n 79) del personal tenía experiencia mayor a tres años, el 75% (n: 113) pertenecían al género femenino, el 47% (n: 71) eran licenciados en enfermería. Conclusiones: Los profesionales enfermeros han logrado mediante sus fortalezas disciplinares dar respuesta a las necesidades del paciente pediátrico y su familia frente a la crisis sanitaria. Las competencias desarrolladas en la administración de los recursos disponibles, la adaptación, flexibilidad a los procesos y líneas estratégicas en tiempo real, posicionan al enfermero como un valor fundamental en el cuidado asistencial (AU)

Introduction: The SARS CoV-2 pandemic posed a challenge for the entire healthcare team. It was necessary to analyze and reflect on the role of nursing in the care of patients and their families in this context. Care processes had to be adapted to new and diverse situations that were generated by the care for patients who usually had associated comorbidities. The aim of the study was to describe the nursing role and the implementation of different protocols and processes for patient care in pediatric inpatient wards in the COVID area of a tertiary-care hospital. Material and methods: a retrospective descriptive study was conducted in the nursing personnel involved in the care of suspected or confirmed cases of COVID-19 during the pandemic and the protocols implemented for nursing care. Results: only 52.5% (n: 79) of the personnel had more than three years of experience, 75% (n: 113) were female, and 47% (n: 71) had a nursing degree. Conclusions: Through their disciplinary strengths, nursing professionals have been able to respond to the needs of pediatric patients and their families in the face of the health crisis. The skills developed in the management of available resources, adaptation, and flexibility to processes and real-time strategies, have positioned nurses as a fundamental factor in healthcare (AU)

Application of two-dimensional electrophoresis for monitoring gastrointestinal digestion of milk.

Two-dimensional electrophoresis (2-DE) was used for tracing in vivo gastrointestinal digestion of milk proteins in a rapid model system with rats. Contents of stomach and small intestine from digestion trials with rats given a single dose of milk powder were recovered after 1 hour. They were then subjected to 2-DE (IEF and SDS-PAGE). 2-DE showed undigested proteins in a MW range 13.0-66.0 kDa in stomach and 13.0-25.0 kDa in the small intestine, thus indicating that milk proteins are slowly digested. This approach may shed light on pattern of protein digestion and mechanism of amino acid and peptide assimilation.

Cytotoxic chemotherapy in the treatment of advanced renal cell carcinoma in the era of targeted therapy.

BACKGROUND: Renal cell carcinoma (RCC) is a heterogeneous disease with regards to histology, progression, and response to treatment. Cytotoxic chemotherapy has been extensively studied in metastatic RCC (mRCC). Responses in most studies are modest and the mechanisms of resistance remain poorly understood. Targeted therapies have significantly improved outcomes in mRCC; however, most patients eventually relapse and die of their disease. Early clinical data suggest that combinations of chemotherapy and targeted agents are clinically active and are well tolerated. METHODS: We reviewed the available literature for published clinical trials incorporating traditional chemotherapeutic agents in the treatment of mRCC. These papers were identified through a Medline search and were included if they employed at least one chemotherapeutic agent in the treatment of mRCC. The literature was also reviewed for information regarding mechanisms of chemotherapy resistance. RESULTS: The data regarding the use of cytotoxic chemotherapy in mRCC consist of small, non-randomized phase I and II studies. The major response proportions with single agent chemotherapies are low but combination regimens either with other cytotoxic agents, cytokines, or targeted agents have demonstrated moderate activity. Disparate trial designs and lack of head to head clinical trials make it difficult to compare the efficacy of chemotherapy with that of immunotherapy or targeted agents. Chemotherapy is particularly useful in patients with collecting duct histology and predominantly sarcomatoid differentiation. Chemotherapy resistance may be mediated by overexpression of p-glycoprotein efflux pumps and the dysregulation of the microtubule-hypoxia inducible factor signaling axis. CONCLUSIONS: The role of cytotoxic chemotherapy in the treatment for clear cell RCC remains poorly defined. Cytotoxic chemotherapy is considered a standard of care in patients with mRCC with predominantly sarcomatoid differentiation and collecting duct RCC variants (Motzer et al., 2014). Early trials combining chemotherapy with targeted therapies are generally well tolerated and show clinical activity. A better understanding of the biology of aggressive subsets of RCC and mechanisms of resistance will help elucidate the role of cytotoxic agents in the current treatment paradigm of RCC.

The interaction of ceruloplasmin with Kupffer cells.

The binding and uptake of ceruloplasmin was studied with rat liver cells using gold-labeled probes. Ceruloplasmins from either rat or sheep were used, in which different molecular conformations had been induced according to established biochemical criteria. The native protein from either species could bind not only to the endothelium, but also to Kupffer cells, at variance with previous findings. The proteins which had been converted to the conformation typical of stored molecules--which can be considered aged, but not denatured, according to standard activity and spectroscopic assays--were bound by endothelium irrespective of species, while only rat ceruloplasmin was able to bind to rat Kupffer cells. Internalization of sheep ceruloplasmin occurred with either endothelium or Kupffer cells. This property was lost with isolated suspended Kupffer cells. These findings suggest the presence of receptors for ceruloplasmin on Kupffer cells which are different from those present on endothelial cells.

Heat-induced aggregation of Phaseolus vulgaris L. Proteins: an electron spin resonance study.

The mechanism of heat-induced aggregation of Phaseolus vulgaris L. proteins and of subunit interactions of importance for susceptibility of proteins to proteolysis was studied by electron spin resonance (ESR) spectroscopy. The mobility of a spin label bound to lysine residues was monitored at two different pH-induced (neutral and alkaline) association states of proteins extracted from raw and cooked common bean. The molecular weight of the protein complexes was assessed by size exclusion-high performance liquid chromatography (SE-HPLC) of labeled proteins. Upon alkaline dissociation, both native and denatured protein subunits underwent a reassociation process to form soluble complexes of molecular weight higher than the species originally present at neutral pH. However, unlike native proteins, impaired mobility of the spin label was observed in the aggregates that are formed after dissociation of subunits of denatured proteins, indicating a reduced accessibility of lysine residues. Trapping of lysine residues inside protein aggregates may explain limited digestibility in the small intestine of proteins in cooked legumes.

Perspectives into factors limiting in vivo digestion of legume proteins: antinutritional compounds or storage proteins?

The in vivo protein digestibility of raw and cooked common bean (Phaseolus vulgaris L.) and faba bean (Vicia faba L.) and of protein fractions extracted from them was determined with growing rats. Overnight-fasted rats were intubated with a protein suspension or fed the same amount of protein added to a basal diet. The rats were killed 1 h later, the contents of stomach and small intestine were washed out, and their protein contents were measured. The in vivo digestibility of proteins of raw common bean flour was 72.4% and not significantly improved after cooking. In contrast, the digestibility of faba bean proteins was decreased from 86.5 to 60.6% by the thermal treatment. Globulins from either species had similar digestibilities (approximately 70%). Proteins in the soluble fraction of cooked beans were more digestible than those in the insoluble fraction, which contained the bulk of the proteins. Hemagglutination assay and trypsin inhibitor determination indicated that after the thermal treatment only very low, nonharmful, levels of both lectin and inhibitor remained. Faba bean contained more polyphenols than common bean samples, with most of the polyphenols being bound to globulins. However, protein-bound polyphenols were markedly decreased after cooking. SDS-PAGE characterization of the gastrointestinal digesta of globulins and amino acid analysis of undigested proteins of whole cooked common bean and faba bean suggested that it is mainly the structural properties of the storage proteins and not their binding of polyphenols, which determines the extent of protein aggregation on autoclaving and may therefore be responsible for their low digestibility.

Investigation of the mechanisms affecting Cu and Fe bioavailability from legumes: role of seed protein and antinutritional (nonprotein) factors.

Chemical composition and content in polyphenols, phytic acid, and dietary fiber of whole cooked common bean (Phaseolus vulgaris L.) and faba bean (Vicia faba L.) and of soluble and insoluble fractions separated from them were determined. Simultaneous determination of Cu, Fe, and protein bioavailability in the small intestine of rat was carried out in single-dose, short-term (1 h) experiments. After cooking, about 80% of seed components (on a weight basis) of either legume was recovered in the precipitate (insoluble fraction) after extraction with water. Protein, lipid, starch, dietary fiber, and polyphenols underwent the most severe insolubilization, together with more than 70% of total Cu and Fe. Cu, Fe, and protein bioavailability showed a similar trend (i.e., the lower the protein, the lower the Cu and Fe availability). Availability of proteins, Cu, and Fe in the insoluble fractions were the lowest, but Cu bioavailability was higher than that of Fe in all fractions. The results provide evidence that the heat-induced insolubilization process adversely affects not only protein but also Cu and Fe bioavailability from legumes and that polyphenols are likely to be a major inhibitor on absorption.

Brote de Ralstonia mannitolilytica a partir de bacteriemias asociadas a catéteres implantables y semiimplantables en un hospital pediátrico / Outbreak of Raistonia mannitolilytica by implantable and semi-implantable catheter-related bacteremia in a pediatric hospital

Ralstonia mannitolilytica junto con Ralstonia pickettii han sido asociadas con brotes hospitalarios relacionados con la contaminación de algún dispositivo o fluido. El objetivo de este trabajo fue describir un brote por R. mannitolilytica a partir de bacteriemias asociadas a catéteres implantables y semiimplantables ocurrido en un hospital pediátrico de alta complejidad y evaluar la utilidad del empleo de métodos moleculares para su investigación.Se detectó la presencia de bacilos gram negativos no fermentadores, con igual antibiotipo, en hemocultivos y retrocultivos a partir de dos pacientes que tenían catéteres implantables y estaban atendidos en una misma área del hospital. Se realizaron estudios microbiológicos de muestras de frascos de heparina, soluciones de dextrosa y soluciones antisépticas con resultado negativo. Algunos pacientes tuvieron signos y/o síntomas clínicos de bacteriemia al habilitar los catéteres para su uso. Se citaron para su estudio a todos los pacientes que habían tenido un procedimiento de apertura y cierre de catéter durante las fechas cercanas a los hallazgos en hemocultivos (N expuestos = 45). Ocurrieron 17 casos (infectados), a partir de los cuales se analizaron 23 aislamientos, en los que se pudo documentar la presencia de R. mannitolilytica (23 aislamientos). Por métodos moleculares se determinó que los aislamientos provenientes de muestras de pacientes involucrados en el brote se encontraban estrechamente relacionados y podrían representar una misma cepa o clon. Por evidencia circunstancial se consideró a la "solución heparínica de cierre" como fuente posible del brote (AU)

Both Ralstonia mannitolilytica and Ralstonia pickettii have been associated with hospital outbreaks due to device or fluid contamination. The aim of this study was to describe an implantable- or semi-implantable-catheter-related bacteremia outbreak by R. mannitolilytica in a tertiary-care hospital and to assess the usefulness of molecular analysis for the identification of the organism. Non-fermenting gram-negative bacilli, with identical antibiotypes, were detected in hemocultures of two patients with implantable catheters in the same hospital area. Microbiological studies of heparin and dextrose and antiseptic solution vials were negative. Some of the patients had clinical signs and/or symptoms of bacteremia when the catheter was prepared for use. All patients who underwent a procedure of accessing or locking the port of the catheter around the time of the positive hemoculture findings were contacted (N exposed = 45). Seventeen infections were detected, of which 23 isolates were analyzed. The presence of R. mannitolilytica was recorded in 23 isolates. Molecular analysis showed that the isolates from the samples of the patients involved in the outbreak were closely related and might represent the same strain or clone. Circumstantial evidence suggested that the heparin-lock solution may have been the source of the outbreak (AU)

Programa de prevención de las bacteriemias asociadas a catéteres venosos centrales / Program for prevention of central venous catheter-related bacteremia

Introducción: Las infecciones son las complicaciones más importantes asociadas al uso de los Catéteres Venosos Centrales (CVC), representan un riesgo 20 veces mayor de bacteriemias que los catéteres venosos periféricos. El objetivo de este estudio fue evaluar el efecto de la implementación de un paquete de medidas o "bundle" en las infecciones asociadas a catéteres venosos centrales (BACT- CVC) en la Unidad de Cuidados Intensivos del Hospital Garrahan (UCI). Métodos: El Programa de Intervención para disminuir las bacteriemias asociadas a catéteres venosos centrales requirió de la aplicación de cuatro paquetes de medidas y un subprograma para aumentar la adherencia a la higiene de manos. Se aplicó en todas las UCI, pero en el presente estudio se presenta como modelo de referencia el que se llevó a cabo en una de ellas. Período del estudio: se compararon 2 períodos: basal (1º Agosto de 2008 - 31 de Diciembre de 2009) y intervención (1º de Enero 2010 al 31 de Diciembre de 2011). La tasa de BACT - CVC se calculó en concordancia con los protocolos utilizados por el sistema NHSN - CDC de los Estados Unidos y el sistema nacional VIHDA. La base de datos utilizada para el estudio fue el software provisto por el programa VIHDA. Se compararon las tasas de BACT - CVC en el período previo y posterior a las intervenciones realizadas. Para el análisis estadístico se utilizó el programa EPIINFO. Se consideró estadísticamente significativo un valor de p < 0.05. Resultados: en el primer período (Agosto 2008 - Diciembre 2009) se produjeron un total de 44 BACT - CVC, con una tasa promedio de 9.64 BACT-CVC por 1000 días-catéter versus 17 BACT - CVC, tasa promedio de 4.41 BACT-CVC por 1000 días-catéter en el período en que se desarrolla el programa de intervención. Esta disminución resulta estadísticamente significativa (Chi cuadrado; valor P= 0,0048; RR 0,46; IC 95%: 0,26 - 0,80). Conclusiones: La aplicación de los combos y el subprograma para mejorar la adherencia a la higiene de manos según orientación de la OMS y aplicando Estrategias Multimodales, resultaron en una mejora significativa en la tasa de BACT- CVC (AU)

Introduction: Infections are the main complication associated with the use of central venous catheters (CVC), accounting for an infection risk about 20 times that of peripheral venous catheters. The aim of this study was to assess the effect of the implementation of sets of measures or "bundle" for the prevention of CVC-associated bacteremia (CVC-BACT) in the ICU. Methods: The intervention program for the reduction of CVC-BACT consisted of four sets of measures and a sub-program to increase adherence to hand hygiene. Bundle use was started in all PICUs, however, in this study implementation of the program in one of them was used as a reference model. Study period: Two periods were compared: Baseline (August 1, 2008 ­ December 31, 2009) and intervention (January 1, 2010 ­ December 31, 2011). The CVC-BACT rate was calculated according to the NHSN-CDC protocols of the United States and the Argentine VIHDA system. For the data base of the study software provided by the VIHDA program was used. CVC-BACT rates before and after the intervention period were calculated. For statistical analysis the EPIINFO program was used. A p < 0.05 was considered significant. Results: In the first period (August 2008 - December 2009) 44 CVC-BACT occurred, with a mean CVC-BACT rate of 9.64 per 1000 catheter days versus 17 CVC-BACT, mean CVC-BACT rate of 4.41 per 1000 catheter days, in the intervention period. This decrease was statistically significant (Chi square 7.94; p = 0.0048; RR 0.46; 95% CI: 0.26 ­ 0.80). Conclusions: Bundle use and the subprogram for better adherence to hand hygiene, according to WHO guidelines and applying multimodal strategies, resulted in a significantly lower CVC-BACT rate (AU)