Perioperative metabolic changes in patients undergoing cardiac surgery

Perioperative metabolic changes in cardiac surgical patients are not only induced by tissue injury and extracorporeal circulation per se: the systemic inflammatory response to surgical trauma and extracorporeal circulation, perioperative hypothermia, cardiovascular and neuroendocrine responses, and drugs and blood products used to maintain cardiovascular function and anesthesia contribute to varying degrees. The pathophysiologic changes include increased oxygen consumption and energy expenditure; increased secretion of adrenocorticotrophic hormone, cortisol, epinephrine, norepinephrine, insulin, and growth hormone; and decreased total tri-iodothyronine levels. Easily measurable metabolic consequences of these changes include hyperglycemia, hyperlactatemia, increased aspartate, glutamate and free fatty acid concentrations, hypokalemia, increased production of inflammatory cytokines, and increased consumption of complement and adhesion molecules. Nutritional risk before elective cardiac surgery-defined as preoperative unintended pathologic weight loss/low amount of food intake in the preceding week or low body mass index-is related to adverse postoperative outcome. Improvements in surgical techniques, anesthesia, and perioperative management have been designed to minimize the stressful stimulus to catabolism, thereby slowing the wasting process to the point where much less nutrition is required to meet metabolic requirements. Early nutrition in cardiac surgery is safe and well tolerated.

Phenotypic and genetic variation in leptin as determinants of weight regain

Over 75% of obese subjects fail to maintain their weight following weight loss interventions. We aimed to identify phenotypic and genetic markers associated with weight maintenance/regain following a dietary intervention.

Body contouring surgery following bariatric surgery and dietetically induced massive weight reduction: a risk analysis

BACKGROUND: This study analyzed the impact of weight reduction method, preoperative, and intraoperative variables on the outcome of reconstructive body contouring surgery following massive weight reduction. METHODS: All patients presenting with a maximal BMI >/=35 kg/m(2) before weight reduction who underwent body contouring surgery of the trunk following massive weight loss (excess body mass index loss (EBMIL) >/= 30%) between January 2002 and June 2007 were retrospectively analyzed. Incomplete records or follow-up led to exclusion. Statistical analysis focused on weight reduction method and pre-, intra-, and postoperative risk factors. The outcome was compared to current literature results. RESULTS: A total of 104 patients were included (87 female and 17 male; mean age 47.9 years). Massive weight reduction was achieved through bariatric surgery in 62 patients (59.6%) and dietetically in 42 patients (40.4%). Dietetically achieved excess body mass index loss (EBMIL) was 94.20% and in this cohort higher than surgically induced reduction EBMIL 80.80% (p < 0.01). Bariatric surgery did not present increased risks for complications for the secondary body contouring procedures. The observed complications (26.9%) were analyzed for risk factors. Total tissue resection weight was a significant risk factor (p < 0.05). Preoperative BMI had an impact on infections (p < 0.05). No impact on the postoperative outcome was detected in EBMIL, maximal BMI, smoking, hemoglobin, blood loss, body contouring technique or operation time. Corrective procedures were performed in 11 patients (10.6%). The results were compared to recent data. CONCLUSION: Bariatric surgery does not increase risks for complications in subsequent body contouring procedures when compared to massive dietetic weight reduction.

Body weight, insulin resistance, and serum adipokine levels 2 years after 2 types of bariatric surgery.

OBJECTIVE: Bariatric surgery reverses obesity-related comorbidities, including type 2 diabetes mellitus. Several studies have already described differences in anthropometrics and body composition in patients undergoing Roux-en-Y gastric bypass compared with laparoscopic adjustable gastric banding, but the role of adipokines in the outcomes after the different types of surgery is not known. Differences in weight loss and reversal of insulin resistance exist between the 2 groups and correlate with changes in adipokines. METHODS: Fifteen severely obese women (mean body mass index [BMI]: 46.7 kg/m(2)) underwent 2 types of laparoscopic weight loss surgery (Roux-en-Y gastric bypass=10, adjustable gastric banding=5). Weight, waist and hip circumference, body composition, plasma metabolic markers, and lipids were measured at set intervals during a 24-month period after surgery. RESULTS: At 24 months, patients who underwent Roux-en-Y were overweight (BMI 29.7 kg/m(2)), whereas patients who underwent gastric banding remained obese (BMI 36.3 kg/m(2)). Patients who underwent Roux-en-Y lost significantly more fat mass than patients who underwent gastric banding (mean difference 16.8 kg, P<.05). Likewise, leptin levels were lower in the patients who underwent Roux-en-Y (P=.003), and levels correlated with weight loss, loss of fat mass, insulin levels, and Homeostasis Model of Assessment 2. Adiponectin correlated with insulin levels and Homeostasis Model of Assessment 2 (r=-0.653, P=.04 and r=-0.674, P=.032, respectively) in the patients who underwent Roux-en-Y at 24 months. CONCLUSION: After 2 years, weight loss and normalization of metabolic parameters were less pronounced in patients who underwent gastric banding compared with patients who underwent Roux-en-Y gastric bypass. Our findings require confirmation in a prospective randomized trial.

Loss of appetite in acutely ill medical inpatients: physiological response or therapeutic target?

Loss of appetite and ensuing weight loss is a key feature of severe illnesses. Protein-energy malnutrition (PEM) contributes significantly to the adverse outcome of these conditions. Pharmacological interventions to target appetite stimulation have little efficacy but considerable side effects. Therefore nutritional therapy appears to be the logical step to combat inadequate nutrition. However, clinical trial data demonstrating benefits are sparse and there is no current established standard algorithm for use of nutritional support in malnourished, acutely ill medical inpatients. Recent high-quality evidence from critical care demonstrating harmful effects when parenteral nutritional support is used indiscriminately has led to speculation that loss of appetite in the acute phase of illness is indeed an adaptive, protective response that improves cell recycling (autophagy) and detoxification. Outside critical care, there is an important gap in high quality clinical trial data shedding further light on these important issues. The selection, timing, and doses of nutrition should be evaluated as carefully as with any other therapeutic intervention, with the aim of maximising efficacy and minimising adverse effects and costs. In light of the current controversy, a reappraisal of how nutritional support should be used in acutely ill medical inpatients outside critical care is urgently required. The aim of this review is to discuss current pathophysiological concepts of PEM and to review the current evidence for the efficacy of nutritional support regarding patient outcomes when used in an acutely ill medical patient population outside critical care.

Loss on ignition as a method for estimating organic and carbonate content in sediments: reproducibility and comparability of results

Five test runs were performed to assess possible bias when performing the loss on ignition (LOI) method to estimate organic matter and carbonate content of lake sediments. An accurate and stable weight loss was achieved after 2 h of burning pure CaCO3 at 950 °C, whereas LOI of pure graphite at 530 °C showed a direct relation to sample size and exposure time, with only 40-70% of the possible weight loss reached after 2 h of exposure and smaller samples losing weight faster than larger ones. Experiments with a standardised lake sediment revealed a strong initial weight loss at 550 °C, but samples continued to lose weight at a slow rate at exposure of up to 64 h, which was likely the effect of loss of volatile salts, structural water of clay minerals or metal oxides, or of inorganic carbon after the initial burning of organic matter. A further test-run revealed that at 550 °C samples in the centre of the furnace lost more weight than marginal samples. At 950 °C this pattern was still apparent but the differences became negligible. Again, LOI was dependent on sample size. An analytical LOI quality control experiment including ten different laboratories was carried out using each laboratory's own LOI procedure as well as a standardised LOI procedure to analyse three different sediments. The range of LOI values between laboratories measured at 550 °C was generally larger when each laboratory used its own method than when using the standard method. This was similar for 950 °C, although the range of values tended to be smaller. The within-laboratory range of LOI measurements for a given sediment was generally small. Comparisons of the results of the individual and the standardised method suggest that there is a laboratory-specific pattern in the results, probably due to differences in laboratory equipment and/or handling that could not be eliminated by standardising the LOI procedure. Factors such as sample size, exposure time, position of samples in the furnace and the laboratory measuring affected LOI results, with LOI at 550 °C being more susceptible to these factors than LOI at 950 °C. We, therefore, recommend analysts to be consistent in the LOI method used in relation to the ignition temperatures, exposure times, and the sample size and to include information on these three parameters when referring to the method.

Determinants of Weight Evolution Among HIV-Positive Patients Initiating Antiretroviral Treatment in Low-Resource Settings.

BACKGROUND In resource-limited settings, clinical parameters, including body weight changes, are used to monitor clinical response. Therefore, we studied body weight changes in patients on antiretroviral treatment (ART) in different regions of the world. METHODS Data were extracted from the "International Epidemiologic Databases to Evaluate AIDS," a network of ART programmes that prospectively collects routine clinical data. Adults on ART from the Southern, East, West, and Central African and the Asia-Pacific regions were selected from the database if baseline data on body weight, gender, ART regimen, and CD4 count were available. Body weight change over the first 2 years and the probability of body weight loss in the second year were modeled using linear mixed models and logistic regression, respectively. RESULTS Data from 205,571 patients were analyzed. Mean adjusted body weight change in the first 12 months was higher in patients started on tenofovir and/or efavirenz; in patients from Central, West, and East Africa, in men, and in patients with a poorer clinical status. In the second year of ART, it was greater in patients initiated on tenofovir and/or nevirapine, and for patients not on stavudine, in women, in Southern Africa and in patients with a better clinical status at initiation. Stavudine in the initial regimen was associated with a lower mean adjusted body weight change and with weight loss in the second treatment year. CONCLUSIONS Different ART regimens have different effects on body weight change. Body weight loss after 1 year of treatment in patients on stavudine might be associated with lipoatrophy.

Predictors of weight stability in women and men: The aerobic center longitudinal study, 1987--1995

It is estimated that more than half the U.S. adult population is overweight or obese as classified by a body mass index of 25.0–29.9 or ≥30 kg/m 2, respectively. Since the current treatment approaches for long-term maintenance of weight loss are lacking, the National Institutes of Health state that an effective approach may be to focus on weight gain prevention. There is a limited body of literature describing how adults maintain a stable weight as they age. It is hypothesized that weight stability is the result of a balance between energy consumption and energy expenditure as influenced by diet, lifestyle, behavior, genetics and environment. The purpose of this research was to examine the dietary intake and behaviors, lifestyle habits, and risk factors for weight change that predict weight stability in a cohort of 2101 men and 389 women aged 20 to 8 7 years in the Aerobic Center Longitudinal Study regardless of body weight at baseline. At baseline, participants completed a maximal exercise treadmill test to determine cardiorespiratory fitness, a medical history questionnaire, which included self-reported measures of weight, dietary behaviors, lifestyle habits, and risk factors for weight change, a three-day diet record, and a mail-back version of the medical history questionnaire in 1990 or 1995. All analyses were performed separately for men and women. Results from multivariate regression analyses indicated that the strongest predictor of follow-up weight for men and women was previous weight, accounting for 87.0% and 81.9% of the variance, respectively. Age, length of follow-up and eating habits were also significant predictors of follow-up weight in men, though these variables only explained 3% of the variance. For women, length of follow-up and currently being on a diet were significantly associated with follow-up weight but these variables explained only an additional 2% of the variance. Understanding the factors that influence weight change has tremendous public health importance for developing effective methods to prevent weight gain. Since current weight was the strongest predictor of previous weight, preventing initial weight gain by maintaining a stable weight may be the most effective method to combat the increasing prevalence of overweight and obesity. ^

Calidad poscosecha del tomate (Solanum lycopersicum L.) cultivado en sistemas ecológicos de fertilización

Se condujeron cuatro experimentos unifactoriales en condiciones de campo en áreas agrícolas de la Universidad de Granma, en el período comprendido de septiembre/2007 a enero/2010 para determinar el efecto de la aplicación de micorrizas arbusculares, Azotobacter chroococcum y ácidos húmicos sobre la productividad y la calidad poscosecha del tomate (Solanum lycopersicum L.) cv. “Vyta”, sobre un suelo de tipo Fluvisol. La aplicación simple y combinada de las micorrizas arbusculares, el Azotobacter chroococcum y los ácidos húmicos mostró un efecto positivo sobre la productividad de la variedad de tomate estudiada, al obtenerse incrementos significativos de este indicador en comparación con el control (sin aplicación), lográndose los mejores resultados con la combinación Glomus fasciculatum (0,3 kg m-2) + Azotobacter chroococcum (30 L ha-1) + ácidos húmicos (500 mg L-1) con valores de 54,57 t ha-1. Se comprobó además, que los tratamientos con estos bioproductos presentaron contenidos de sólidos solubles totales (SST), carbohidratos solubles totales (CST), vitamina C, porcentaje de materia seca (PMS), firmeza, longitud y anchura de los frutos superiores al control (sin aplicación). Las plantas controles (sin aplicación) significativamente incrementaron la acidez titulable (contenido de ácido cítrico) y la pérdida de peso y redujeron el pH de los frutos del tomate. Los análisis de correlación realizados revelan que existieron correlaciones positivas y significativas entre el contenido de vitamina C, materia seca, sólidos solubles totales, carbohidratos solubles totales, y el pH de los frutos, mientras que la acidez titulable presentó correlaciones negativas y significativas con todas las variables mencionadas anteriormente. Se encontró a su vez un efecto sinérgico en las plantas con la aplicación combinada de estos productos con respecto al control (sin aplicación), expresado en los mayores valores de los parámetros micorrízicos estudiados. ABSTRACT Four unifactorial experiments under field conditions in an agricultural area belonging to the University of Granma from September/2007 to January/2010 aiming to evaluate the effect of arbuscular mycorrhizas, Azotobacter and humic acids on tomato (Solanum lycopersicum L) cv. “Vyta” crop yield and postharvest quality in a Typic Fluvent soil were conducted. The simple and mixed application of arbuscular mycorrhizas, Azotobacter chroococcum and humic acids showed a positive effect on yield and internal postharvest parameters evaluated for the studied tomato variety, achieving significant increases with respect to the control treatment ones. The best results related to crop yield were achieved by combining Glomus fasciculatum (0.3 kg m-2) + Azotobacter chroococcum (30 L ha-1) + humic acids (500 mg L-1) that lead to 54.57 t ha-1. In addition, it was also demonstrated that the treatments under effect of biofertilizers and biostimulants resulted in higher total soluble solids (TSS), total soluble carbohydrates (TSC), vitamin C, dry matter contents (DMC), firmness, length and width of the fruits than the control treatment. The control plants showed significantly increased titrable acidity (citric acid content) and weight loss and reduced pH on the tomato fruits. The conducted correlation analyses revealed that there were significant and positive correlations between vitamin C content, dry matter, total soluble solids, total soluble carbohydrates, and pH of the fruit, while titratable acidity showed significant negative correlations with all variables mentioned above. At the same time, a synergic effect by mixed utilization of these biological products on tomato plants, with respect to control treatment (non-treated), was found regarding the increase of studied mycorrhizal parameters.