Nicolás Velasco

Gut mucosal atrophy after a short enteral fasting period in critically ill patients.

PURPOSE The purpose of this study was to evaluate the presence of gut mucosal atrophy and changes in mucosal permeability in critically ill patients after a short fasting period. MATERIALS AND METHODS Fifteen critically ill patients underwent a period of enteral fasting of at least 4 days (mean 7.8 days). We took the following measurements the day before initiating enteral nutrition: indirect calorimetry, serum albumin, prealbumin, and lymphocyte count. We also performed a duodenal endoscopic biopsy with histopathological and mucosal morphometric analysis including villus height and crypt depth. The lactulose-mannitol test was performed to assess gut permeability. A total of 28 healthy volunteers served as controls for duodenal biopsy or lactulose-mannitol test. Clinical data, such as length of fasting, severity score, and previous parenteral nutritional support, were recorded. RESULTS We found gut mucosal atrophy, expressed as a decrease in villus height and crypt depth, in patients compared with controls. The patients also exhibited an abnormal lactulose-mannitol test. Morphometric changes did not correlate with permeability. Further, we found no correlation between the results of the lactulose-mannitol test and of mucosal morphometry with clinical data. CONCLUSIONS We found that a short period of enteral fasting was associated with significant duodenal mucosal atrophy and abnormal gut permeability in critically ill patients.

Influence of legume intake on biliary lipids and cholesterol saturation in young Chilean men: Identification of a dietary risk factor for cholesterol gallstone formation in a highly prevalent area*

Chileans and North American Indians have one of the highest prevalence rates of cholesterol gallstones in the world. The most common theory to explain this has been the operation of some as yet undefined genetic risk factor in these populations. Searching for some common environmental factor for gallstones in Chileans and North American Indians, we found that beans and other legumes are common foods consumed by both populations. In this study we tested the hypothesis that legume intake may favor the production of biliary cholesterol supersaturation. We studied 20 young men subjected to a diet containing 120 g/day of legumes and a control diet without legumes for a period of 1 mo each. Both diets supplied identical quantities of energy, carbohydrates, protein, total fat, fiber, and cholesterol. Low-density lipoprotein cholesterol concentration decreased by 16% (p less than 0.001) after the legume diet. Biliary cholesterol saturation increased in 19 of the 20 subjects; the mean of the group markedly increased from 110% to 169% (p less than 0.001) after the legume diet. These results are consistent with the hypothesis that legume intake is a potential risk factor for cholesterol gallstone disease.

Identification of ferroelectric domain structures in BaTiO3 for Raman spectroscopy

Conventional Raman spectroscopy on BaTiO 3 determines vibrational modes by integrating over a macroscopic sample volume. In domain-rich materials and to account for microscopic surface domains, an experimental study of the domain distribution is desirable. We applied polarized light microscopy (PLM) and piezo-response force microscopy (PFM) to 40 μm thick BaTiO 3 single crystals in order to get an exact model of the domain distribution, which allows to allocate the laser spot of a micro-Raman spectrograph within a specific domain type. We are able to assign most of the Raman-active normal modes in polarized measurements, which are free of ferroelastic domain walls but not necessarily free of ferroelectric walls. We propose to study the influence of ferroelectric walls on the asymmetric peak shapes by an in situ combination of PFM and micro-Raman spectroscopy.

Comparison of Three Methods for the Estimation of Total Nitrogen Losses in Hospitalized Patients

Since the measurement of total nitrogen output (TNO) is not routinely determined in the clinical setting, its level is frequently estimated using formulas based on the urinary urea nitrogen excretion (UUN). We measured TNO in 124 surgical patients over 990 days (TNO, 19.22 +/- 8.72 g N/day; total urinary nitrogen (TUN) 18.17 +/- 8.70 g N/day; UUN, 15.17 +/- 7.70 g N/day; mean gastrointestinal nitrogen (MGIN) 0.68 +/- 0.49 g N/day; integumental nitrogen (ITGN), 0.34 +/- 0.08 g N/day) and compared the results with the daily estimations using three different formulas: formula A, UUN + 4; formula B, UUN x 1.20 + 1.05, where 1.20 is the reciprocal of the mean ratio UUN/TUN and 1.05 the mean extraurinary nitrogen losses; and formula C, UUN x 1.0986 + 2.55, derived from the regression analysis of UUN vs TNO. TNO estimated by these formulas were 19.17 +/- 7.70, 19.26 +/- 9.24, and 19.22 +/- 8.70 g N/day, respectively. The regression analyses of the estimated TNO from the three formulas versus the measured TNO indicated that formulas A, B and C were equally accurate in estimating TNO over the entire range of UUN. However, when only values of UUN greater than or equal to 30 g N were considered, a modified formula A (UUN + 6) was the best predictor of TNO. Daily audits of the differences between the estimated and measured TNO showed comparable results for the three formulas. In 28.4 to 31.1% of the observed days the differences were higher than +/- 2 g N/day, an error which is not acceptable when estimating the protein requirements in many clinical conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of polymeric enteral nutrition supplemented with different doses of glutamine on gut permeability in critically ill patients

OBJECTIVES To evaluate the effect of glutamine-supplemented polymeric enteral formulas on the recovery of gut-permeability abnormalities in critically ill patients. METHODS Twenty-three patients were randomized to receive a conventional casein-based enteral formula (ADN), ADN plus glutamine in a dose of 0.15 g x kg(-1) x d(-1) or ADN plus 0.30 g x kg(-1) x d(-1) of glutamine for 8 d. The lactulose mannitol permeability test (L/M) was performed at baseline and at the end of the study. Nineteen healthy volunteers served as controls for the L/M test. RESULTS An increase in permeability compared with control subjects was observed in patients at baseline (mean +/- standard error of the mean; L/M ratio: 0.11 +/- 0.03 and 0.025 +/- 0.004, respectively; P < 0.02). The L/M ratio improved after the period of enteral nutrition as a whole (initial L/M: 0.11 +/- 0.03, final L/M: 0.061 +/- 0.01; P < 0.03), but no difference was found between groups. CONCLUSIONS Even though polymeric enteral nutrition was associated with a significant improvement in the L/M ratio, glutamine supplementation did not show a specific influence in improving recovery of gut permeability in critically ill patients.

Validación de cuestionario autoaplicable para un índice de alimentación mediterránea en Chile

Background: Availability of brief dietary indexes that can effectively evaluate dietary patterns and their association with health is critical for prevention and management of several chronic disease conditions. Aim: To adapt a self-applicable Mediterranean Dietary Index in Chile (Chilean-MDI). Material and Methods: The Chilean-MDI was developed based on a previous Mediterranean eating score that was adapted to Chilean dietary habits. This index was further validated in a sample of 153 adults by comparing the concordance between the results obtained by self-application of the Chilean-MDI with those obtained by a trained nutritionist. Additionally, the index was applied in a sample of 53,366 Chilean adults in order to describe the diet quality of our population. Results: There was an adequate concordance between findings obtained by self-application of the Chilean-MDI and those achieved by the nutritionist. The application of the index in Chilean adult population showed a better diet quality (high Mediterranean diet adherence) among women, with advanced age and among people with higher educational levels. Conclusions: The Chilean-MDI can be successfully self-applied to portray the overall diet quality in the Chilean adult population. Additionally, the Chilean-MDI describes overall food intake in our population, showing demographic trends that are comparable to those obtained with similar indexes applied in other populations.BACKGROUND Availability of brief dietary indexes that can effectively evaluate dietary patterns and their association with health is critical for prevention and management of several chronic disease conditions. AIM To adapt a self-applicable Mediterranean Dietary Index in Chile (Chilean-MDI). MATERIAL AND METHODS The Chilean-MDI was developed based on a previous Mediterranean eating score that was adapted to Chilean dietary habits. This index was further validated in a sample of 153 adults by comparing the concordance between the results obtained by self-application of the Chilean-MDI with those obtained by a trained nutritionist. Additionally, the index was applied in a sample of 53,366 Chilean adults in order to describe the diet quality of our population. RESULTS There was an adequate concordance between findings obtained by self-application of the Chilean-MDI and those achieved by the nutritionist. The application of the index in Chilean adult population showed a better diet quality (high Mediterranean diet adherence) among women, with advanced age and among people with higher educational levels. CONCLUSIONS The Chilean-MDI can be successfully self-applied to portray the overall diet quality in the Chilean adult population. Additionally, this dietary index describes overall food intake in Chilean adults, showing demographic trends that are comparable to those obtained with similar indexes applied in other populations.

Actividad física y su asociación con factores de riesgo cardiovascular: Un estudio en adultos jóvenes

Background: Physical activity (PA) has a protective role in cardiovascular diseases. Aim: To quantify PA in young adults and to correlate it with cardiovascular risk factors. Material and Methods: A cross-sectional study was performed employing the international physical activity questionnaire (IPAQ), to measure the PA of 983 randomly selected young adults from Valparaiso region born between 1974 and 1978. Its results were associated with levels of obesity, insulin resistance and cardiovascular risk factors defined by the National Cholesterol Education Program-Adult Treatment Panel III (NCEP- ATP III) Results: Mean physical activity among men and women was 3731 ± 3923 and 1360 ± 2303 METs-minutes/week, respectively (p < 0.001). Fifty percent of women and 21.5% of men had an insuffcient level of physical activity (p < 0.001). Sixty percent of men and 23.4% of women had an intense level of physical activity (p < 0.001). There was an inverse association of physical activity and insulin resistance. A high physical activity was protective, specially among men, against a low HDL cholesterol level and high triglyceride levels with Odds Ratios of 0.59 (confdence interval (CI): 0,35-0.98) and 0.49 (CI: 0,27-0,87) respectively, after adjusting for body mass index and age. Conclusions: In this sample, men had higher levels of physical activity, that was protective against insulin resistance and the presence of cardiovascular risk factors.

Inverse Associations between a Locally Validated Mediterranean Diet Index, Overweight/Obesity, and Metabolic Syndrome in Chilean Adults

Obesity and metabolic syndrome (MetS) are key risk factors for chronic disease. Dietary patterns are critical in the incidence and persistence of obesity and MetS, yet there is few data linking diet to obesity and MetS in Chile. Our objective was to use a locally validated diet index to evaluate adherence to a Mediterranean dietary pattern and its correlations with overweight/obesity (OW/O) and MetS prevalence in Chilean adults. We conducted a nationwide, cross-sectional online survey of Chilean adults with complete self-reported diet and body mass index data (n = 24,882). A subsample of 4348 users (17.5%) had valid MetS data. An inverse association was observed between adherence to Mediterranean diet and OW/O and MetS prevalence. As diet quality decreased from healthy, to moderately-healthy, to unhealthy, prevalence increased from 44.8, 51.1, to 60.9% for OW/O and from 13.4, 18.5, to 28.9% for MetS (p-values < 0.001). Adjusted odds ratios for OW/O and MetS were significantly higher in moderately-healthy (OR = 1.58 and 1.54) and unhealthy (OR = 2.20 and 2.49, respectively) diet groups in comparison to the healthy diet group. This study represents the first report on the relationship between Mediterranean diet and chronic disease risk in Chile. It suggests that the Mediterranean diet may be applied to manage chronic disease risk beyond the Mediterranean basin.

Evidencia actual sobre los beneficios de la dieta mediterránea en salud

The Mediterranean diet is currently considered a functional diet with an increasing amount of scientific evidence that supports its beneficial effects in human health. Several observational cross-sectional and prospective cohort studies show an association between this diet and a lower prevalence and incidence of chronic diseases, such as cardiovascular disease, cancer, metabolic syndrome, diabetes, and neurodegenerative diseases as well as a reduced overall mortality. Additionally, clinical interventional studies, particularly the PREDIMED (Prevencion con Dieta Mediterranea) initiative, have shown, with high quality scientific evidence, that a Mediterranean diet -supplemented either with olive oil or nuts- can lower by 30% the incidence of cardiovascular disease, reverse the metabolic syndrome, and prevent the development of diabetes and aging-related cognitive decline. Chile has one of the five Mediterranean ecosystems in the world, and therefore the implementation of this food pattern and lifestyle in our country may determine large benefits to the health status and quality of life in the Chilean population.

Características Clínicas y Metabólicas de los estados de Intolerancia a la glucosa y Glicemia de ayuno alteradas

Background: Subjects with glucose intolerance or high fasting glucose levels have a higher cardiovascular risk and frequently become diabetic. Aim: To assess clinical and metabolic characteristics of patients with glucose intolerance or high fasting glucose levels. Material and methods: Fasting and post glucose load serum glucose and insulin levels were measured in 1404 people, aged 42,0 ± 14,2 years (81% women) with high diabetic risk. We categorized subjects in different alterations of blood glucose, according to 2006 American Diabetes Association categories. Insulin resistance (RI), insulin secretion (s %) and insulin disposition (ID), were calculated using fasting blood glucose and insulin levels, using the homeostasis model assessment (HOMA I and II). Results: Sixty percent of studied subjects had first grade relatives with diabetes mellitus and 1097 (78%) were categorized as normal (N), 45 (3%) as Diabetes Mellitus (DM), 161 (11%) as high fasting glucose levels (GAA) and 103 (7%) as glucose intolerant (ITG). Fifty three of the 106 subjects with GAA (50%), were also glucose intolerant. Subjects with GAA had similar insulin sensitivity and lower s cell function than N (insulin disposition 58 ± 12 and 111 ± 32%, respectively, p <0.01). ITG had less insulin sensitivity than N (HOMA-IR 2.6 ± 1.50 ± and 2.0 ± 1.30, respectively) and only a mild decrease in s cell function (insulin disposition 96 ± 26 and 111 ± 32% respectively, p < 0.01). Patients GAA plus ITG had similar alterations than those with DM (HOMA-IR 3.8 ± 2.2 and 4.4 ± 3.7 respectively; insulin disposition 57 ± 10 and 56.0 ± 26% respectively. Conclusions: Patients with higher fasting glucose levels behave differently from those with glucose intolerance. High fasting glucose levels are highly prevalent in subjects with high risk of DM and must be considered as risk indicator in preventive programs for diabetes mellitus (Rev Med Chile 2009; 137: 193-9). (Key words: Glucose intolerance; Insulin; Insulin resistance)