Influence of a 36 h fast followed by refeeding with glucose,glycerol or placebo on metabolism and performance during prolonged exercise in man

Summary Five men were studied during exercise to exhaustion on an electrically braked cycle ergometer at 70% of % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVq0xe9tqqrpepC0xbbL8F4rqqrFfpeea0xe9sq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0Firpepe0de9vr0-vr% 0-vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaKaaGkqadAfaga% GaaOWaaSbaaSqaaiaab+eadaWgaaqccawaaiaabkdacaqGGaGaaeyB% aiaabggacaqG4baameqaaaWcbeaaaaa!3C9E!\[\dot V_{{\text{O}}_{{\text{2 max}}} } \]. The four experimental treatments were as follows: fasted for 36 h (A); fasted (36 h) and refed with glucose (B) or glycerol (C); postabsorptive (overnight fast, D). In B and C the subjects were given a drink containing glucose or glycerol (lg per kg body weight) 45 min before starting exercise. A placebo drink was given 45 min before exercise on treatments A and D. Despite an increased availability of circulating free fatty acids, -hydroxybutyrate and glycerol exercise time to exhaustion was significantly lower after fasting (treatment A 77.7±6.8 min) compared with treatment D (119.5±5.8 min). Refeeding with glucose or glycerol did not significantly improve performance (92.4±11.8 min and 80.8±3.6 min respectively) compared with treatment A and lowered circulating levels of FFA and — HB during exercise compared with A. Despite the probability of low liver glycogen levels after fasting, none of the subjects became hypoglycaemic (blood glucose <4 mmol · l^–1) during exercise and their blood lactate concentrations were not high at exhaustion. Plasma levels of branched chain amino acids (BCAA) decreased progressively during exercise on treatments A, B and C and were considerably lower at exhaustion compared with treatment D. Falling plasma concentrations of BCAA during prolonged exercise may be implicated in the generation of central fatigue.     

Metabolic, hormonal, oxidative, and inflammatory factors in pediatric obesity-related liver disease

OBJECTIVE: To examine the role of metabolic, hormonal, oxidative, and inflammatory factors in pediatric obesity-related liver disease. STUDY DESIGN: In 50 obese children (age 7 to 14 years) with (n = 20, group 1) or without (n = 30, group 2) hypertransaminasemia and ultrasonographic liver brightness, we studied insulin resistance (fasting glucose/insulin ratio [FGIR]) and serum levels of leptin, iron, transferrin, ferritin, C-reactive protein (CRP), white blood cell (WBC) count, tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, C282Y and H63D mutations, and erythrocytic glutathione peroxidase (GPX) activity. RESULTS: FGIR (6.7 +/- 4.1 vs 9.2 +/- 5.2; P = .02), serum ferritin (88.8 +/- 36.0 vs 39.9 +/- 24.0 ng/mL; P = .0001), serum CRP (5.4 +/- 6.0 vs 1.1 +/- 1.6 mg/dL; P = 0.004), and GPX (8.4 +/- 0.9 vs 5.0 +/- 0.5 U/g Hb; P = .05) were significantly higher and more frequently deranged in group 1 than in group 2. FGIR, ferritin, and CRP values were simultaneously deranged in 41% of the group 1 patients and in none of the group 2 patients ( P = .098). Serum leptin, iron, and transferrin, WBC, TNF-alpha, IL-6, and C282Y and H63D mutations were similar in the 2 groups. CONCLUSIONS: Insulin resistance, oxidative stress, and low-grade systemic inflammatory status are implicated in pediatric obesity-related liver disease. These findings may be useful in planning pathophysiologically based therapeutic trials for hepatopathic obese children who are unable to follow hypocaloric diets.     

Fasting versus gradual initiation of the ketogenic diet: a prospective, randomized clinical trial of efficacy

PURPOSE: The ketogenic diet (KD) is a 90% fat diet that is an effective treatment for intractable epilepsy. Rapid initiation of the KD requires hospital admission because of the complexity of the protocol and frequent mild and moderate adverse events. The purpose of the study was to compare the efficacy of a gradual KD initiation with the standard KD initiation preceded by a 24- to 48-h fast. METHODS: Children ages 1 to 14 years with intractable epilepsy were randomized to a fasting initiation (FAST-KD) or gradual initiation (GRAD-KD). Baseline seizure activity was recorded daily for 28 days before admission and continued for the 3-month duration of the study. Effectiveness was measured in two ways: (a) the proportion of subjects with >50% reduction in target seizure type from baseline to 3-month evaluation, and (b) percentage reduction in the frequency of the target seizure type from baseline to 3-month evaluation. Blood glucose was assessed q4 to 6h, and weights, electrolytes, hydration status, vomiting, acid balance, need for interventions (citric acid and sodium citrates (Bicitra) and IV fluids) were assessed daily. Fisher's exact tests were used to examine the association between protocol and occurrence of adverse events, and longitudinal mixed-effects models were used to look for trends in tolerability data over time. RESULTS: Forty-eight subjects, 24 in each arm, were randomized. In the FAST-KD protocol, 58% of the children had >50% reduction in the target seizure type at 3 months, and 21% were seizure free. In the GRAD-KD protocol, 67% had a >50% reduction at 3 months, and 21% were seizure free. The two protocols were equivalent in efficacy (p = 0.033). At 3 months, the FAST-KD median percentage seizure reduction rate was 78% (ranging from 100% reduction to 73% increase in seizures per week) and was 94% (ranging from 100% reduction to 161% increase in seizures per week) for the GRAD-KD protocol. By using a logarithmic transformed percentage reduction rate and an equivalence limit difference of 20%, the efficacy of the two protocols was equivalent (p = 0.0002). Children in the GRAD protocol lost significantly less weight (p = 0.006), and had fewer and less-severe episodes of hypoglycemia (p < 0.001), fewer treatments for acidosis (citric acid and sodium citrates) (p < 0.04) and dehydration (IV fluids) (p < 0.04), but no difference in vomiting was noted. CONCLUSIONS: These data suggest that in children with intractable epilepsy, a gradual initiation results in fewer adverse events and is tolerated better overall while maintaining the efficacy of the KD.     

Validation of surrogate estimates of insulin sensitivity and insulin secretion in children and adolescents

OBJECTIVES: To compare insulin sensitivity and pancreatic beta-cell function measured by the euglycemic and the hyperglycemic clamp, with simple estimates of insulin sensitivity and pancreatic beta-cell function in youth.Study design We measured insulin sensitivity with a euglycemic clamp and first- and second-phase insulin secretion with a hyperglycemic clamp in 156 AA and white youths. Estimates of insulin sensitivity (fasting insulin level [I(F)], the ratio of fasting glucose [G(F)] to I(F) [G(F)/I(F)], homeostasis model assessment estimate of insulin sensitivity [HOMA IS], and quantitative insulin sensitivity check index [QUICKI]) and estimates of pancreatic beta-cell function (I(F), the ratio of I(F) to G(F) [I(F)/G(F)], and homeostasis model assessment estimate of pancreatic beta-cell function [HOMA %B]) were derived from fasting measurements. RESULTS: In the total group, IS(Eu) correlated strongly with I(F) (r=-0.92), G(F)/I(F) (r=0.92), HOMA IS (r=0.91), and QUICKI (r=0.91) (P<.01). First-phase and second-phase insulin secretion correlated with I(F), I(F)/G(F), and HOMA %B (first-phase insulin secretion: r=0.76, 0.79, 0.82; second-phase insulin secretion: r=0.83, 0.86, 0.86, respectively; P<.01). CONCLUSIONS: Simple estimates of insulin sensitivity and pancreatic beta-cell function using fasting insulin and glucose levels serve as surrogate measures of insulin sensitivity and secretion in nondiabetic youths. The validity of these conclusions in children with impaired glucose tolerance and type 2 diabetes mellitus remains to be determined.     

Patterns of eating and movement that best maintain reduction in overweight

Two studies of the influences of specific patterns of eating and exercising behaviour on body weight in English Midlands women were re-analysed using correlations as the measure of effect size. As predicted from computational modelling of hunger-sating mechanisms, avoiding energy-containing drinks and foods at the ends of and between meals was the behaviour most influencing year-long weight loss. However, although eating between meals is often called snacking, the term 'snack' appeared to be too ambiguous in this culture for its use in helping efforts to control weight. Avoidance of particular sorts of fat-rich foods was also associated with longer-term weight loss. Attempts at severe restriction of intake at mealtimes were associated with weight loss during a period of intensive dieting, but did not contribute to maintenance of that weight reduction. Using diet formulae to attain rapid weight loss was associated with significant weight gain over a year. These results support the suggestion that the first line of defence against weight gain is avoiding all sources of energy during drink breaks, with personally relevant advice on lower fat versions of particular foods also being important. Continued neglect of the behaviour-specific correlational approach to gaining evidence for less fattening habits does nothing to slow the rise in obesity.     

Scopolamine-induced convulsions in fasted mice after food intake: determination of blood glucose levels, [3H]glutamate binding kinetics and antidopaminergic drug effects

The present study was performed to evaluate the role(s) of hypoglycemia, changes in [(3)H]glutamate binding kinetics and dopaminergic activity in the occurrence of scopolamine-induced convulsions in fasted mice after food intake. Plasma glucose levels and density (B(max)) and affinity (K(d)) of [(3)H]glutamate binding sites in whole brain synaptic membranes were determined in animals fed ad lib or fasted for 48 h and treated intraperitoneally (i.p.) with 3 mg/kg scopolamine or saline and allowed to eat for 5 min. Fasting for 48 h decreased plasma glucose levels. After refeeding, plasma glucose concentrations increased in saline treated animals, but remained unchanged in scopolamine treated animals which consumed less food. Fasting for 48 h also produced significant changes in the kinetics of [(3)H]glutamate binding. The B(max) and K(d) of the binding sites decreased in fasted animals. These changes were partially antagonized by scopolamine treatment and food intake. For the evaluation of the contribution of dopaminergic activity, another group of mice fasted for 48 h and pretreated (i.p.) with saline or dopamine antagonists, 2 mg/kg chlorpromazine or 2 or 4 mg/kg haloperidol, were treated 10 min later with either saline or 3 mg/kg scopolamine. Then 20 min later, they were allowed to eat ad lib and were observed for 30 min for the incidence and onset of clonic convulsions. Pretreatment of both 2 mg/kg chlorpromazine and 4 mg/kg haloperidol markedly suppressed the convulsions. These results indicate that the decrease in the [(3)H]glutamate binding induced by fasting, its antagonism by scopolamine treatment and food intake, and the dopaminergic hyperactivity may be possible factors contributing to the occurrence of convulsions.     

Effect of the long-term regular intake of virgin olive oil on the phenolic metabolites in human fasting plasma

The effect of repeated consumption of virgin olive oil on endogenous phenolic metabolites of fasting plasma is unknown. For this reason, we hypothesized that regular long-term virgin olive oil intake could have an indirect protection effect on the endogenous phenols. Thus, the aim of the study was to determine the phenolic profile of human plasma in a fasting state of long-term regular virgin olive oil consumers, using the fasting plasma of non-consumers as a natural control. Forty participants living in the area of Reus (Catalonia, Spain) were selected, 20 life-long regular consumers of virgin olive oil and a natural control of 20 non-consumers, the latter being Rumanians who dislike the taste of olive oil. The diet was obtained from 3-day food records. The results showed similar phenolic composition of fasting plasmas of the two volunteer groups. Of special interest is that more of the compounds quantified showed higher concentration in fasting plasma from habitual virgin olive oil consumers. The compounds were semi-quantified using caffeic acid as the calibration standard. The quantification of fasting consumer's plasma showed higher concentration of a hydroxyflavanone type compound (2.90 ± 0.04 μM vs 1.5 ± 0.04 μM) and a catecholamine derivative (0.70 ± 0.03 μM vs 0.56 ± 0.03 μM) than the plasma of non-consumers (P < 0.05). The results suggest an indirect protective mechanism of long-term regular virgin olive oil consumption related to the protection of the endogenous antioxidant system.     

糖尿病糖化血红蛋白监测的临床意义

本文测定65例糖化血红蛋白、空腹血糖正常参考值 GHb6.34±S1.21%;FPG4.98±S0.88mmol/L,两者呈正相关,相关系数 r0.511,P<0.01。185例糖尿病病人GHb9.95±S2.90%;FPG10.96±S5.07 mmol/L,两者相关系数 r0.7225 P<0.01。将正常人组、糖尿病组、糖尿病控制较差组、控制较好组进行统计分析,各组之间的 GHb、FPG 都有显著性差异 P<0.01。GHb 监测是观察糖尿病疗效、病情控制好否一个有效指标。连续随诊的两例糖尿病患者 GHb、FPG 监测结果看出病情控制好否、GHb,FPG 含量高低与合并症发生有一定关系。     

Combined effects of fasting and alanine on liver function recovery after cold ischemia

The effect of donor nutritional status on hepatic function recovery after cold ischemia is still debated. We demonstrated previously that a 48-h fast diminished the survival rate of liver-transplanted rats and that the deleterious effect of fasting was prevented by infusion of alanine to the recipient at reperfusion. Whether the duration of fasting influenced the protective effect of alanine and whether this effect was metabolic were not known, and the elucidation of these questions is the aim of this study. The effect on hepatic function recovery of fasting periods of 24 h, 48 h and 72 h prior to cold ischemia were studied in a model of isolated, perfused rat liver. After a cold-ischemic time of 24 h in University of Wisconsin (UW) solution at 4 degrees C, livers were reperfused for 3 h. The combined effect of alanine (8 mM) infusion at liver reperfusion was evaluated for each prior fasting period. The addition of pyruvate (8 mM), a metabolic intermediary of alanine, was only tested in the 72-h fasting group. The evaluation criteria were: liver weight after reperfusion, release of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) in the perfusate, bile production, vascular resistance and liver histology after reperfusion. The enzyme release at reperfusion was significantly higher when livers were harvested from rats submitted to a 48-h fast (ALT) or a 72-h fast (ALT, AST, LDH), as compared to those from fed rats. Vascular resistance was increased in 72-h fasted livers. An addition of alanine (8 mM) at reperfusion lowered the release of AST, ALT and LDH. This effect was more obvious when the fasting duration was increased. By contrast, the addition of pyruvate at reperfusion did not improve the recovery of livers submitted to a 72-h fasting period before preservation. A long fasting period is deleterious as compared to feeding; however, this effect can be compensated by infusion of alanine at reperfusion. The mechanism involved is not metabolic. In a clinical setting, the infusion of alanine to the recipient at reperfusion may be a convenient way to compensate for donor undernutrition, especially after a long stay in an intensive care unit.     

择期手术患儿禁食、禁饮时间的研究

目的 :探讨择期手术患儿 (非胃肠道手术 )术前禁食、禁饮时间对患儿机体的影响。方法 :将 3 3 5例分离麻醉下非胃肠道择期手术患儿随机分为两组 ,对照组采用术前常规禁食 12h ,禁饮4h～ 6h。实验组根据患儿的需要于手术前 2h可饮少许水或吸吮冰块、水果糖等 ,术前 6h禁食。结果 :对照组由于禁食禁饮时间长 ,患儿易出现口渴、饥饿、烦躁等不适 ,术中发生误吸情况两组比较无统计学意义 (P >0 .0 5 )。结论 :针对每位患儿的实际情况和具体手术时间 ,实施术前 2h禁饮、6h禁食 ,可减少患儿不适 ,满足患儿机体的需要