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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

D-xylose pharmacokinetics has been studied in 6 healthy subjects by serial measurement of blood and urinary levels following oral and intravenous administration of two doses of D-xylose (5 and 25 g successively). Furthermore, patients with obesity, renal or hepatic insufficiency, or with a T-drain after cholecystectomy, are also investigated. Both the rate and completeness of D-xylose absorption and the apparent distribution volume of D-xylose present noteworthy interindividual variations, so that the time and value of the peak blood level are highly variable as between healthy subjects. Renal insufficiency increases the apparent elimination half-life of D-xylose and notably reduces D-xylose renal excretion. This study provides pharmacokinetic evidence of the very wide range of blood and urinary levels observed in the D-xylose tolerance test, and emphasizes the fact that D-xylose urinary excretion alone is not a reliable index of intestinal absorption.
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PMID:[D-xylose absorption test. A pharmacokinetic and statistical study]. 62 49

Seven subjects who underwent jejunoileal bypass surgery for massive obesity participated in a study to examine the relative bioavailability of digoxin before and one to two months after surgery. They were given a loading dose of 1 mg digoxin in divided oral doses followed by oral maintenance doses of 0.5 mg daily. There were no significant differences in the area under the serum concentration time curve, steady state serum levels or 24 hour steady state excretion of digoxin before and after surgery. We conclude that the bioavailability of digoxin from the Lanoxin tablets employed is not impaired in these patients, although urinary d-xylose and 24 hour fecal fat excretion indicated moderate to severe malabsorption after surgery.
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PMID:The effect of jejunoileal bypass on the pharmacokinetics of digoxin in man. 83 89

Food intake was measured in 22 obese patients before and after jejunioleostomy for obesity. Most of the weight loss could be accounted for by the observed reduction of caloric intake. Malabsorption was also present as indicated by increased loss of fat in the stools, and decreased absorption of D-xylose and vitamin B12. A dislike for sweet tastes developed after surgery in most patients. Preferences for concentrated solutions of sucrose and glucose were reduced after patients showed a depression of food intake by a 440-calorie preload which had not been detected before surgery. These studies show a decrease in food intake after intestinal bypass surgery and suggest a role for taste or other gastrointestinal factors in regulating food intake.
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PMID:Intestinal bypass surgery for obesity decreases food intake and taste preferences. 93 32

The effects of increasing cell size on glucose transport activity and metabolism and on the concentrations of glucose transport systems in both the plasma and low density microsomal membranes in isolated adipose cells from the aging rat model of obesity have been examined. Glucose transport activity was assessed by measuring l-arabinose transport and the concentration of glucose transport systems estimated by measuring specific d-glucose-inhibitable cytochalasin B-binding. Basal glucose transport activity increases from 0.3 to 1.4 fmol/cell/min with a 10-fold increase in cell size, but remains constant per unit cellular surface area and is accompanied by a constant 5 pmol of glucose transport systems/mg of membrane protein in the plasma membrane fraction. Maximally insulin-stimulated glucose transport activity, on the other hand, remains constant at 2.3 fmol/cell per min with increasing cell size, but markedly decreases per unit cellular surface area and is accompanied by a decrease from 30 pmol of glucose transport systems/mg of plasma membrane protein to the basal level. These diminished effects of insulin on glucose transport activity and the number of glucose transport systems in the plasma membrane fraction in enlarged cells are paralleled by an 80% decrease in the basal number of glucose transport systems/mg of membrane protein in the low density microsomal membrane fraction, the source of those glucose transport systems appearing in the plasma membrane in response to insulin. The effects of cell size on the metabolism of a low concentration of [1-(14)C]glucose (0.56 mM) directly parallel those on glucose transport activity and the concentration of glucose transport systems in the plasma membrane fraction, and are not associated with significant alterations in the cell's sensitivity to insulin. Thus, adipose cellular enlargement is accompanied by the development of a marked "insulin resistance" at the glucose transport level, which may be the consequence of a relative depletion of glucose transport systems in the intracellular pool.
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PMID:Mechanism of insulin-resistant glucose transport activity in the enlarged adipose cell of the aged, obese rat. 674 3

After resection and usually after shunt operations for obesity, the small bowel in-situ or in-continuity develops mucosal hyperplasia and enhanced absorption per unit length of intestine in animals and man, although the studies in man are limited. The opposite occurs in the small bowel deprived of food either by bypass or total parenteral nutrition (TPN). The changes which occur in the bypassed bowel are not consistent and cannot be explained by the luminal nutrition theory alone. The effect of TPN on jejunal function has been assessed in preterm infants using the one hour blood xylose test and potential difference changes after the infusion of glucose. The results of these tests suggest that the absorptive surface area is diminished during TPN, increases following enteral feeding, and is not related to post-natal age. Function at a cellular level probably remains constant. The mechanism of adaptation is poorly defined in man, but animal studies suggest that in addition to luminal nutrition, other factors such as hormones, and pancreatico-biliary secretions, are important but that there is a fine balance of agonists and antagonists.
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PMID:Adaptation of the small intestine--does it occur in man? 681 78

The effect of Orlistat, a lipase inhibitor used in the treatment of obesity was studied on gastrointestinal transit time, on body composition and on hormones known to be influenced by the degree of hydrolysis of nutritional triglycerides or by reduced nutrient intake and absorption. After a placebo run-in period 14 patients were randomized to a 12-week treatment period on Orlistat 360 mg per day (mean body weight 93.1 +/- 9.8 kg) or placebo (mean body weight 90.7 +/- 10.5 kg). At randomization and after 12 weeks body weight, body composition, thyroid hormones, catecholamines, insulin-like growth factor I (IGF-I) and IGF-binding protein 3 were measured. During 4 hours after consumption of a liquid fat-rich mixed meal containing study medication, 15 g lactulose and 25 g xylose, blood levels of glucose, insulin, c-peptide, glucagon, triglycerides, free fatty acids, cholecystokinin, pancreatic polypeptide and xylose and expiration air levels of hydrogen were measured. Weight loss was 4.2 +/- 3.5 kg in the Orlistat group versus 3.0 +/- 1.9 kg in the placebo group. Fat mass decreased to an equal degree, whereas lean body mass remained stable. No differences were found for thyroid hormones, catecholamines, IGF-I and IGFBP-3 levels. By comparing the areas under the curve (AUC) and the peak levels at randomization (acute effects) of insulin and c-peptide a tendency was found to be increased in the Orlistat group, whereas those of xylose were increased significantly, suggesting faster gastric emptying after Orlistat. No differences were found in the other parameters. By comparing the changes in responses (longer term effects) no significant differences were found. In conclusion, the presence in the gut of undigested and unabsorbed fat does not seem to have a relevant influence on hormonal status and body composition in a small group of moderately obese patients.
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PMID:Lipase inhibition and hormonal status, body composition and gastrointestinal processing of a liquid high-fat mixed meal in moderately obese subjects. 865 34

Severely malnourished children afflicted by acute lymphoblastic leukemia (ALL), particularly in developing countries, have reduced tolerance to chemotherapy and a compromised prospect for survival. We investigated the prevalence and severity of alterations in growth and nutritional status in children with ALL from population-based referral areas in Canada. All children were treated with Dana-Farber Cancer Institute ALL Consortium protocols. First, the relative impact of cranial irradiation (CI) and chemotherapy on growth was studied in 116 children at diagnosis and at 6-month intervals during treatment. We observed a decline in height standard deviation (SD) score in the first year in all children, and a further decline in height SD score during the second year only in the children who received CI. Weight reduction occurred in the first year, but during the second year there was a disproportionate increase in weight compared with height, suggesting that children treated with ALL have a tendency toward obesity. Both chemotherapy and CI contribute to the altered growth observed in children treated for ALL. Second, intestinal functional integrity was assessed in 16 children during post-induction chemotherapy. Nutrient intake was adequate and there was minimal evidence of malabsorption: fat malabsorption occurred in only 1 child (after treatment-related pancreatitis), abnormal D-xylose absorption occurred in 2 children at 6 months of therapy (returning to normal 6 months later) and abnormal lactose absorption occurred in 4 children. Third, weight, height, whole body lean and fat mass measured by dual-energy X-ray absorptiometry and serum albumin were determined at diagnosis and at 6-month intervals throughout therapy in 19 children with ALL. Height SD scores decreased significantly during treatment. Serum albumin was abnormally low in 6/19 at diagnosis and 14/18 during intensive consolidation therapy. The mean change in the ratio of lean mass to total body weight showed a 5% reduction by 6 months of therapy. Body fat increased from a mean of 22% at diagnosis to 28% at completion of therapy. The majority of children treated for ALL thus have significant changes in nutritional status manifested by reductions in growth, alterations in lean and fat body mass and abnormally low serum proteins during intensive therapy.
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PMID:Growth and body composition in response to chemotherapy in children with acute lymphoblastic leukemia. 987 86

Obesity is a major cause of health complaints in western developed countries. Problems ranging from apnea to joint pain have been associated with excess weight. Many factors have been attributed to the epidemic of obesity including sedentary lifestyle, high-fat diets and consumption of large amounts of processed foods. Pharmacies and health-food store shelves abound with a vast selection of products promoted for weight-loss. Some of these have made headlines recently for the damaging effect they have on such things as cardiac valvular function. Unfortunately, others will probably follow and original data is presented on potentially dangerous natural products. Alternatives are presented and discussed below. These natural alternatives include such things as digestive enzyme inhibitors (e.g. L-arabinose, hibiscus tea, marine algae, Nomame Herba, etc), anorexics (e.g. monoterpenes such as d-limonene and perillyl alcohol), glucose-uptake inhibitors (e.g. phlorizin), and probiotics as adjuvants. These all-natural products are presented as some possible alternatives to those that could be potentially lethal and are not meant as the only options.
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PMID:Weight-loss drugs and supplements: are there safer alternatives? 1186 96

The immune and neuroendocrine systems are closely involved in the regulation of metabolism at peripheral and central hypothalamic levels. In both physiological (meals) and pathological (infections, traumas and tumors) conditions immune cells are activated responding with the release of cytokines and other immune mediators (afferent signals). In the hypothalamus (central integration), cytokines influence metabolism by acting on nucleus involved in feeding and homeostasis regulation leading to the acute phase response (efferent signals) aimed to maintain the body integrity. Peripheral administration of cytokines, inoculation of tumor and induction of infection alter, by means of cytokine action, the normal pattern of food intake affecting meal size and meal number suggesting that cytokines acted differentially on specific hypothalamic neurons. The effect of cytokines-related cancer anorexia is also exerted peripherally. Increase plasma concentrations of insulin and free tryptophan and decrease gastric emptying and d-xylose absorption. In addition, in obesity an increase in interleukin (IL)-1 and IL-6 occurs in mesenteric fat tissue, which together with an increase in corticosterone, is associated with hyperglycemia, dyslipidemias and insulin resistance of obesity-related metabolic syndrome. These changes in circulating nutrients and hormones are sensed by hypothalamic neurons that influence food intake and metabolism. In anorectic tumor-bearing rats, we detected upregulation of IL-1beta and IL-1 receptor mRNA levels in the hypothalamus, a negative correlation between IL-1 concentration in cerebro-spinal fluid and food intake and high levels of hypothalamic serotonin, and these differences disappeared after tumor removal. Moreover, there is an interaction between serotonin and IL-1 in the development of cancer anorexia as well as an increase in hypothalamic dopamine and serotonin production. Immunohistochemical studies have shown a decrease in neuropeptide Y (NPY) and dopamine (DA) and an increase in serotonin concentration in tumor-bearing rats, in first- and second-order hypothalamic nuclei, while tumor resection reverted these changes and normalized food intake, suggesting negative regulation of NPY and DA systems by cytokines during anorexia, probably mediated by serotonin that appears to play a pivotal role in the regulation of food intake in cancer. Among the different forms of therapy, nutritional manipulation of diet in tumor-bearing state has been investigated. Supplementation of tumor bearing rats with omega-3 fatty acid vs. control diet delayed the appearance of tumor, reduced tumor-growth rate and volume, negated onset of anorexia, increased body weight, decreased cytokines production and increased expression of NPY and decreased alpha-melanocyte-stimulating hormone (alpha-MSH) in hypothalamic nuclei. These data suggest that omega-3 fatty acid suppressed pro-inflammatory cytokines production and improved food intake by normalizing hypothalamic food intake-related peptides and point to the possibility of a therapeutic use of these fatty acids. The sum of these data support the concept that immune cell-derived cytokines are closely related with the regulation of metabolism and have both central and peripheral actions, inducing anorexia via hypothalamic anorectic factors, including serotonin and dopamine, and inhibiting NPY leading to a reduction in food intake and body weight, emphasizing the interconnection of the immune and neuroendocrine systems in regulating metabolism during infectious process, cachexia and obesity.
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PMID:Hypothalamic integration of immune function and metabolism. 1687 87

Metabolic alterations including postprandial hyperglycemia have been implicated in the development of obesity-related diseases. Xylose is a sucrase inhibitor suggested to suppress the postprandial glucose surge. The objectives of this study were to assess the inhibitory effects of two different concentrations of xylose on postprandial glucose and insulin responses and to evaluate its efficacy in the presence of other macronutrients. Randomized double-blind cross-over studies were conducted to examine the effect of D-xylose on postprandial glucose and insulin response following the oral glucose tolerance test (OGTT). In study 1, the overnight-fasted study subjects (n = 49) consumed a test sucrose solution (50 g sucrose in 130 ml water) containing 0, 5, or 7.5 g D-xylose powder. In study 2, the overnight-fasted study subjects (n = 50) consumed a test meal (50 g sucrose in a 60 g muffin and 200 ml sucrose-containing solution). The control meal provided 64.5 g of carbohydrates, 4.5 g of fat, and 10 g of protein. The xylose meal was identical to the control meal except 5 g of xylose was added to the muffin mix. In study 1, the 5 g xylose-containing solutions exhibited significantly lower area under the glucose curve (AUCg) and area under the insulin curve (AUCi) values for 0-15 min (P < 0.0001, P < 0.0001), 0-30 min (P < 0.0001, P < 0.0001), 0-45 min (P < 0.0001, P < 0.0001), 0-60 min (P < 0.0001, P < 0.0001), 0-90 min (P < 0.0001, P < 0.0001) and 0-120 min (P = 0.0071, P = 0.0016). In study 2, the test meal exhibited significantly lower AUCg and AUCi values for 0-15 min (P < 0.0001, P < 0.0001), 0-30 min (P < 0.0001, P < 0.0001), 0-45 min (P < 0.0001, P = 0.0005), 0-60 min (P = 0.0002, P = 0.0025), and 0-90 min (P = 0.0396, P = 0.0246). In conclusion, xylose showed an acute suppressive effect on the postprandial glucose and insulin surges.
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PMID:Coconut-derived D-xylose affects postprandial glucose and insulin responses in healthy individuals. 2225 78


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