Physical Activity Predicts Weight Loss Following Gastric Bypass Surgery: Findings from a Support Group Survey

Background Patient adherence to recommended eating and physical activity behaviors is considered important to weight loss outcomes following gastric bypass surgery, but there has been little systematic research in this area to investigate behavioral predictors of weight loss. Method We developed a measure of postsurgical behaviors, the bariatric surgery self-management questionnaire (BSSQ). A survey was conducted of 200 patients attending postsurgical support groups (mean time since surgery 14 months, mean age 40 years, 85% female, presurgical weight 150 kg). Patients completed the BSSQ and measures of treatment regimen distress, perceived benefits of weight loss, and weight-related physical symptoms. Results Mean BSSQ adherence was in the 70% range, with subscale scores varying considerably. Distress levels associated with the new lifestyle were consistently low (≈20%) and perceived benefits of weight loss were high early on and maintained consistently (70–90%). A final predictive model showed premorbid weight, time since surgery, and BSSQ physical activity subscale were significant predictors of weight loss, accounting for 73% of variance. Conclusions Physical activity adherence was the sole significant behavioral predictor of weight loss, although maladaptive dietary habits and patient selection issues were identified for future research. It will be important to replicate the current study in prospective, longitudinal studies with representative patient cohorts. A challenge for researchers will be to develop novel, intensive recruiting and retention strategies to allow closer examination of these issues.     

Patients Who are Delayed from Undergoing Bariatric Surgery Do Not have Improved Weight Loss

Background Many patients have a prolonged wait time between initial surgeon visit and actual surgery day. Whereas there are various reasons for this, few have examined if patient wait time for bariatric surgery has any affect on weight loss. This investigation studies the hypothesis that patients who wait longer for bariatric surgery do not have improved weight loss over those with shorter wait times. Methods All patients in a private academic practice who underwent laparoscopic gastric bypass over a 6-month period were included in this study. The time from initial office visit to actual surgery date was calculated to be wait time (WT). Reasons for short or long WT were not investigated. The relationship between WT and percentage excess body weight loss (%EBWL) was examined. In addition, patients whose WT was greater than 6 months (WT > 6) were compared to those less than 6 months (WT < 6). Pearson’s correlation coefficients and two-tailed Mann–Whitney tests were used as appropriate. Results There were 104 patients with 99 patients who had a >1 year follow-up. WT did not correlate with %EBWL (r = 0.09, p = 0.37). There was no difference in %EBWL in the WT > 6 group versus the WT < 6 group (73 vs. 70%; p = NS). Patients who had <50% EBWL waited an average of 281 versus 254 days for those who have >50% EBWL (p = NS). Conclusions Patients who wait longer before having bariatric surgery do not show improved weight loss. Weight loss success was not related to wait time. These results suggest that prolonged mandatory weight times are not an effective method for improving bariatric surgery weight loss outcomes. Mandatory delays for bariatric surgery should not be required, as they have no scientific merit. Presented at the World Congress of the International Federation for the Surgery of Obesity, Sydney, Australia, September 1, 2006.     

Muscle Force and Force Control After Weight Loss in Obese and Morbidly Obese Men

BACKGROUND: Decrease in fat mass and fat-free mass have been observed with weight loss induced by a dietary intervention or surgery. There are concerns that fat-free mass decrease could have some negative functional consequences. The aim of this study was to examine how weight loss affects strength and force control in obese and morbidly obese men. METHODS: Weight loss was obtained in obese individuals by a hypocaloric diet program until resistance to lose fat and in morbidly obese individuals by bariatric surgery. Maximal force was measured for upper and lower limb and the ability to maintain 15% and 40% of that force. These measures were taken at baseline, in those dieting once resistant to weight loss and 1 year after surgery for those operated on. Normal weight individuals used for control were evaluated twice (6 to 12 months apart). RESULTS: At baseline, there was no significant difference between groups for maximal forces and capabilities to maintain force levels. Weight loss averaged 11.1% of the initial body weight after dieting and 46.3% 1 year after surgery. At the same time, there was for the lower limb a loss of 10.1% in maximal force after dieting and 33.5% after surgery. For the upper limb, there was no change in maximal force after dieting whereas a decrease of 14.4% was observed after surgery. When transformed in force related to body weight, there was no change in relative force for the lower limb after dieting whereas an increased relative force after surgery. There was no significant difference for the ability for maintaining force levels. CONCLUSION: Despite a large force loss, particularly for the lower limbs in morbidly obese individuals after surgery, this loss is relatively well tolerated because the relation between force and body weight is even improved and the ability to maintain that force is preserved.     

Alveolar-Membrane Diffusing Capacity Improves in the Morbidly Obese after Bariatric Surgery

Background Morbidly obese individuals may have impaired alveolar-membrane diffusing capacity (DmCO). The purpose of this study was to measure pulmonary diffusing capacity for NO (DLNO) as an index of DmCO pre- and postbariatric surgery in the morbidly obese. Methods Twenty-one patients [age = 40 ± 9 years, body mass index (BMI) = 48.5 ± 7.2 kg/m²] with an excess weight of 72 ± 17 kg scheduled for bariatric surgery were recruited. Pulmonary function and arterial blood-gases were measured pre- and postsurgery. Results DmCO was 88 ± 23% of predicted before surgery (p < 0.05). There was loss in BMI and excess weight of 7.7 ± 2.0 kg/m² and 31 ± 8%, respectively. Because DmCO = DLNO/2.42, the increase in DLNO postsurgery resulted in a normalization of the predicted DmCO to 97 ± 29% predicted, or an improvement of DLNO by 11 ± 18 (95% CI = 3.5, 19.1; p = 0.01) milliliters per minute per millimeter of mercury without any improvement in DLCO. The DLNO/DLCO ratio and alveolar volume both increased, respectively (p < 0.05), and pulmonary capillary blood volume to DmCO ratio decreased postsurgery (p < 0.01). Multiple linear regression revealed that the change in DLNO was most strongly associated with changes in alveolar volume and the waist-to-hip ratio (adjusted r ² = 0.76; p < 0.001) and was not related to the reduction in the alveolar-to-arterial PO₂ difference. Conclusion Alveolar-membrane diffusion normalizes within 10 weeks after bariatric surgery. This is likely due to the increase in alveolar volume from the reduction in the waist-to-hip ratio. G.S. Zavorsky is the recipient of the 2005 Baxter Corporation Award in Anesthesia from the Canadian Anesthesiologist’s Society. G.S. Zavorsky was a previous Research Scholar – Junior 1 from the Quebec Health Research Foundation (Fonds de la Recherche en Santé du Québec, FRSQ). N.V. Christou is a consultant for Ethicon Endo-Surgery and has stock ownership in Weight Loss Surgery.     

Evidence-based Review of the Bioenterics Intragastric Balloon for Weight Loss

We reviewed clinical studies performed with the Bioenterics intragastric balloon (BIB) to promote weight loss. Thirty studies were included [18 prospective (5 randomized), 12 retrospective], totaling 4,877 patients. Only one of three sham-controlled trials found a significantly higher weight loss with the BIB vs the sham procedure plus exhaustive follow-up. In nonrandomized studies, weight loss with the BIB averaged 17.8 kg (range, 4.9–28.5), corresponding to BMI changes of 4.0–9.0 kg/m². Comorbidities resolved or improved in 52–100% of patients. Best short-term results were observed in patients devoid of binge eating disorder with a BMI in the 30.0–40.0 kg/m² range; the BIB also helped to prepare superobese patients for bariatric surgery. Severe complications were exceptional (gastric perforation and intestinal obstruction; 0.2% each); digestive intolerance prompted early BIB removal in 2.5% of patients. Long-term (≥2 years) results are awaited, as well as well-designed studies to define the best indications for this therapy. Conflict of interest: none     

Incomplete restoration of the secretion of ghrelin and PYY compared to insulin after food ingestion following weight gain in anorexia nervosa

BACKGROUND: In humans, ghrelin has been found to stimulate appetite while PYY3-36 to reduce it; these orexigenic and anorexigenic peptides play significant roles in appetite control. We investigated pre- and postprandial responses of ghrelin and PYY in anorexia nervosa (AN) and the influence of weight gain. METHODS: Plasma ghrelin, PYY3-36, glucose and insulin responses after ingestion of a 400 kcal standard meal were measured in 14 patients with restricting type of AN and 12 controls. The AN patients were evaluated before therapy and after inpatient therapy. Psychometry was performed by the use of Eating Disorders Inventory. RESULTS: Ghrelin was suppressed during the meal test, while PYY3-36 was increased in all of the groups. Before therapy, AN patients had significantly increased levels of ghrelin and PYY3-36 compared to the control (P<0.01). After therapeutic intervention, as the nutritional status of AN patients improved, the secretion of these hormones were increased (P<0.05), but not normalized as in psychological testing. In contrast, insulin and glucose responses were normalized after inpatient therapy. CONCLUSIONS: We found that both ghrelin and PYY3-36 increased in AN patients and these changes were not normalized in contrast to insulin after treatment. The increase in both orexigenic ghrelin and anorexigenic PYY3-36 may have a role in pathological eating behavior in AN.     

高场磁共振射频能量吸收率SAR的研究

目的 通过对SAR影响参数研究,计算10秒SAR,指导MR扫描顺利进行.方法 采用GE公司HD 3T扫描仪,头颅8通道线圈,扫描序列为T2-FSE,改变体重、TR、层数等参数对水模进行扫描,观察SAR的改变.结果 SAR与体重和TR有关,而与扫描的层数无关,SAR是RF、BO、体重和TR的函数.根据体重与10秒SAR的关系曲线,通过MATLAB,进行一个曲线拟合,得出10 s SAR与体重的关系方程式:SAR=((-5.96E-09)X4-(2.08E-06)X3 0.0005681X2-0.04531X 1.638)*Peak_SAR.结论 SAR是RF脉冲序列、B0、体重和TR的函数,我们所得到的MATLAB 4次方程式,只要输入病人体重和Peak_SAR就能直接得到10 s SAR,就可以估计扫描是否暂停,以及暂停时间.     

A randomized, double-blind, placebo-controlled trial of a β-hydroxyl β-methyl butyrate, glutamine, and arginine mixture for the treatment of cancer cachexia (RTOG 0122)

Purpose

Cancer cachexia is a common problem among advanced cancer patients. A mixture of β-hydroxyl β-methyl butyrate, glutamine, and arginine (HMB/Arg/Gln) previously showed activity for increasing lean body mass (LBM) among patients with cancer cachexia. Therefore a phase III trial was implemented to confirm this activity.

Materials and methods

Four hundred seventy-two advanced cancer patients with between 2% and 10% weight loss were randomized to a mixture of β-hydroxyl β-methyl butyrate, glutamine, and arginine or an isonitrogenous, isocaloric control mixture taken twice a day for 8 weeks. Lean body mass was estimated by bioimpedance and skin-fold measurements. Body plethysmography was used when available. Weight, the Schwartz Fatigue Scale, and the Spitzer Quality of Life Scale were also measured.

Results

Only 37% of the patients completed protocol treatment. The majority of the patient loss was because of patient preference (45% of enrolled patients). However, loss of power was not an issue because of the planned large target sample size. Based on an intention to treat analysis, there was no statistically significant difference in the 8-week lean body mass between the two arms. The secondary endpoints were also not significantly different between the arms. Based on the results of the area under the curve (AUC) analysis, patients receiving HMB/Arg/Gln had a strong trend higher LBM throughout the study as measured by both bioimpedance (p?=?0.08) and skin-fold measurements (p?=?0.08). Among the subset of patients receiving concurrent chemotherapy, there were again no significant differences in the endpoints. The secondary endpoints were also not significantly different between the arms.

Conclusion

This trial was unable to adequately test the ability of β-hydroxy β-methylbutyrate, glutamine, and arginine to reverse or prevent lean body mass wasting among cancer patients. Possible contributing factors beyond the efficacy of the intervention were the inability of patients to complete an 8-week course of treatment and return in a timely fashion for follow-up assessment, and because the patients may have only had weight loss possible not related to cachexia, but other causes of weight loss, such as decreased appetite. However, there was a strong trend towards an increased body mass among patients taking the Juven® compound using the secondary endpoint of AUC.     

Neurodegeneration involving putative respiratory neurons in Perry syndrome

The objective of this study was to assess the potential involvement of ventral medullary neurons implicated in respiratory rhythmogenesis and chemosensitivity in a patient with Perry syndrome (autosomal dominant parkinsonism associated with depression, weight loss and central hypoventilation). Previous neuropathologic reports in Perry syndrome demonstrated neuronal loss in the substantia nigra with no or few Lewy bodies and no tau inclusions. Neurons in the pre-Bötzinger complex (preBötC) of the ventrolateral medulla, identified by their immunoreactivity for neurokinin-1 receptors (NK-1R), play an essential role in respiratory rhythmogenesis and serotonergic neurons in the medullary raphe in respiratory chemosensitivity, but their potential involvement in Perry syndrome has not yet been addressed. We conducted clinical and neuropathologic studies including immunohistochemistry examination in a new autopsied case clinically diagnosed as Perry syndrome. Our patient presented with parkinsonism at age 41. Subsequently, all cardinal features of Perry syndrome developed. He died of respiratory failure and sepsis at age 46. Hematoxylin-eosin staining revealed no significant pathology in the medulla. However, NK-1R, tyrosine hydroxylase (TH) and tryptophan hydroxylase (TrOH) immunoreactive neurons were significantly reduced in the ventrolateral medulla compared to controls. There was also loss of serotonergic neurons in the medullary raphe and ventral medullary surface. Severe neuronal loss in the substantia nigra, without alpha-synuclein or tau pathology but with loss of NK-1R and TH immunoreactive neurons in the ventrolateral medulla, and loss of serotonergic neurons in the medullary raphe and ventrolateral medulla may be a pathologic hallmark of Perry syndrome.     

Mixed effects modeling of weight change associated with placebo and pregabalin administration

Objective: To characterize change from baseline weight over time for pregabalin and placebo administration. Methods: Asymptotic fraction of baseline weight was modeled with a nonmixture model and a mixture model as a function of baseline weight, exposure, time, covariate effects, and subject-specific random effects. Model fit was assessed using standard diagnostic plots. Predictive performance was assessed using both data similar to the original data, and open-label data. Results: The nonmixture model indicated that a typical patient (baseline weight 82 kg) receiving placebo or 300 mg/day pregabalin approached an asymptotic fractional change from baseline weight of [mean (95% prediction interval for typical individual)] 0.7% (−5.5% to 7.4%) or 2.5% (−3.8% to 9.1%), respectively, with a half-life of 17 days. Substantial between-subject variability is observed, with some drug-treated subjects remaining weight neutral or losing weight, at all levels of exposure. Structural fixed effects parameters for the two submodels (mixture model) were in close agreement with each other and with those for the nonmixture model. The mixture model described two subpopulations differing in interindividual variability. No significant interindividual-varying covariates influencing the mixture probabilities were identified other than exposure. Both models had adequate fit; both models performed well during external validation. Predictive performance (nonmixture model) was adequate to ~900 days. Conclusions: The weight of a typical 82-kg patient receiving placebo or pregabalin (300 mg/day) approaches an asymptotic fractional change from baseline weight of 0.7%, or 2.5%, respectively, with a half-life of 17 days. Substantial between-subject variability remains unexplained.