Efectos de la glutamina parenteral en pacientes sometidos a trasplante de médula ósea / Effects of parenteral glutamine in patients submitted to bone marrow transplantation

El Trasplante de Médula Ósea (TMO), es un tratamiento utilizado en las neoplasias malignas hematológicas y tumores sólidos. La quimioterapia y/o radioterapia asociadas a que están sometidos estos pacientes, induce efectos secundarios, con un alto estrés metabólico. La glutamina es considerada como un aminoácido condicionalmente esencial y se ha mostrado eficaz en estados catabólicos severos. El objetivo del estudio fue valorar el efecto del tratamiento con Nutrición Parenteral (NP) suplementada con glutamina sobre la duración del soporte nutricional en un grupo de pacientes con TMO. También han sido analizadas las complicaciones asociadas, valoración del estado nutricional, evolución clínica a los 6 meses, diferencias en el tipo de transplante y capacidad de ingesta oral. Se trata de un Ensayo Clínico en fase IV, aleatorizado, doble ciego, paralelo y unicéntrico. El Estudio se realizó en 49 pacientes, 29% varones y 71% mujeres, con edades comprendidas entre 21-63 años, distribuidos en tres grupos diagnósticos (leucemias, linfomas y tumores sólidos), ingresados en el Servicio de Hematología de nuestro Hospital. El 50% de pacientes en cada grupo han recibido NP suplementada con glutamina (0,4 g/kg/día de L-alanil-L-glutamina) y otro 50% han recibido NP Estándar. RESULTADOS: No se han encontrado diferencias significativas, ni al inicio ni al final del estudio entre ambos grupos, en relación con las variables estudiadas. CONCLUSIONES: La NP es un tratamiento efectivo para el mantenimiento del estado nutricional, en los pacientes sometidos a una terapia con efecto altamente catabólico, como es el TMO. Aunque no hemos podido demostrar la eficacia de la suplementación con glutamina en este estudio con la dosis de glutamina utilizada, sí ha resultado ser eficaz en otras publicaciones (AU)

Bone marrow transplantation (BMT) is a therapy used for hematologic malignancies and solid tumors. Associated chemotherapy and radiotherapy to which these patients are submitted induce secondary effects, with a high metabolic stress. Glutamine is considered a conditionally essential amino acid, and has been shown effective in severe catabolic states. The aim of the study was to assess the effect of parenteral nutrition (PN) therapy supplemented with glutamine on duration of nutritional support in a group of patients with BMT. We have also analyzed associated complications, the nutritional status, the clinical course at 6 months, differences as to type of transplantation, and oral ingestion capability. This is a phase IV, randomized, double blind, and parallel clinical trial, done at a single center. The study was performed on 49 patients, 29% male and 71% female patients, with ages between 21-63 years, distributed in 3 diagnostic groups (leukemia, lymphoma, and solid tumors), and admitted to the Hematology Department of our Hospital. Fifty percent of the patients in each group have received PN supplemented with glutamine (0.4 g/kg/day of L-alanine- L-glutamine), and the other 50% have received standard PN. RESULTS: we have not found significant differences nor at the beginning nor at the end of the study between both groups with regards to studied variables. CONCLUSIONS: PN is and effective therapy for maintenance of the nutritional status in patients submitted to a therapy with a, highly catabolic effect such as BMT. Although we have not been able to show the efficacy of glutamine supplementation in this study with the used dose, it does have been effective in other reports (AU)

Sol-Gel Synthesis of Microporous Amorphous Silica from Purely Inorganic Precursors

Aqueous sodium silicate solutions and hydrochloric acid were used to prepare silica gels without any additives. In order to establish the optimum conditions for the preparation of microporous and monodisperse gels, the sol-gel reaction has been studied as a function of pH, concentration of silicate, time, and temperature. From 29Si NMR spectroscopy it was found that polycondensation sets on immediately after mixing the reagents, with a continuous increase of the fraction of 4-connected silicate tetrahedra (Q4) at the expense of Q1 and Q2. Polycondensation continues beyond the gelation point for 1 7, the order increases rapidly with pH. Gels formed at pH > 7 had an electrostatic nature and redissolved in water, whereas for pH