Effects of long versus short bout exercise on fitness and weight loss in overweight females.

OBJECTIVE: The specific aim of this study was to determine if three 10 minute bouts of exercise per day (3 x 10) and two 15 minute bouts per day (2 x 15) were as effective as one 30 minute bout per day (1 x 30) for improving VO2 max and weight loss. METHODS: Overweight, female college students (body mass index > or = 28 kg/m2) were recruited and assessed at baseline and post-treatment for aerobic fitness (Astrand maximal cycle test), weight, skinfold thickness (7-site), and circumference measures (4-site). Following measurement of resting energy expenditure (REE), subjects were asked to follow a self-monitored calorie restricted diet (80% of REE) for the twelve week duration of the study and were assigned (non-random) to one of four treatment groups: 1) a nonexercising control group (control, n = 8), 2) a 30 minutes continuous exercise group (1 x 30, n = 12), 3) a 30 minutes accumulated exercise group (2 x 15, n = 10) and 4) a second 30 minutes accumulated exercise group (3 x 10, n = 8). The exercising subjects participated in aerobic exercise training at 75% of heart rate reserve three to five days per week with all exercise monitored. RESULTS: VO2 max increased significantly while weight, body mass index, sum of skinfolds, and sum of circumferences decreased significantly from baseline to post-treatment in the 1 x 30, 2 x 15 and the 3 x 10 groups, but not in the control group. A tertiary finding was that exercise participation did not differ among the exercising groups with regard to the average number of days per week. CONCLUSIONS: These results support the hypothesis that exercise accumulated in several short bouts has similar effects as one continuous bout with regard to aerobic fitness and weight loss during caloric restriction in overweight, young women.

Predictors of complication and suboptimal weight loss after laparoscopic Roux-en-Y gastric bypass: a series of 188 patients.

HYPOTHESIS: An analysis of patients undergoing laparoscopic Roux-en-Y gastric bypass (RYGB) may identify factors predictive of complication and of suboptimal weight loss. DESIGN: Inception cohort. SETTING: Metropolitan university hospital. PATIENTS: One hundred eighty-eight consecutive patients with severe obesity who met National Institutes of Health consensus guidelines for bariatric surgery. INTERVENTIONS: Laparoscopic RYGB. MAIN OUTCOME MEASURES: Complications requiring therapeutic intervention and percentage of excess body weight lost at 1 year after surgery. RESULTS: Of the 188 patients who underwent laparoscopic RYGB, 50 (26.6%) developed complications that required an invasive therapeutic intervention, including 2 deaths. The average follow-up was 351 days (range, 89-1019 days). Multivariate analysis by stepwise logistic regression identified surgeon experience, sleep apnea (P =.003; odds ratio, 3.0; 95% confidence interval, 1.3-7.1), and hypertension (P =.07; odds ratio, 2.0; 95% confidence interval, 1.0-4.0) as predictors of complications. The most common complication requiring therapeutic intervention was stricture at the gastrojejunal anastomosis, occurring in 27 patients (14.4%). Of the 115 patients who underwent surgery more than 1 year previously, 1-year follow-up data were available for 93 (81%). The body mass index (weight in kilograms divided by the square of height in meters) decreased from 53 +/- 8 preoperatively to 35 +/- 6 at 1 year. The mean +/- SD percentage of excess body weight lost at 1 year was 61% +/- 14%. Diabetes mellitus was negatively correlated with percentage of excess body weight lost at 1 year (P =.06). CONCLUSIONS: Surgeon experience, sleep apnea, and hypertension are associated with complications after laparoscopic RYGB. Diabetes mellitus may be associated with poorer postoperative weight loss.

Effect of cancer cachexia on the activity of tripeptidyl-peptidase II in skeletal muscle.

The ubiquitin-proteasome proteolytic pathway plays a major role in degradation of myofibrillar proteins in skeletal muscle during cancer cachexia. The end-product of this pathway is oligopeptides and these are degraded by the extralysomal peptidase tripeptidyl-peptidase II (TPPII) together with various aminopeptidases to form tripeptides and amino acids. To investigate if a relationship exists between the activity of the proteasome and TPPII, functional activities have been measured in gastrocnemius muscle of mice bearing the MAC16 tumour, and with varying extents of weight loss. TPPII activity was quantitated using the specific substrate Ala-Ala-Phe-7-amido-4-methylcoumarin, while proteasome activity was determined as the 'chymotrypsin-like' enzyme activity. Both proteasome proteolytic activity and TPPII activity increased in parallel with increasing weight loss, reaching a maximum at 16% weight loss, after which there was a progressive decrease in activity for both proteases with increasing weight loss. In murine myotubes, proteolysis-inducing factor, which is a sulphated glycoprotein produced by cachexia-inducing tumours, induced an increase in activity of both proteasome and TPPII, with an identical dose-response curve, and both activities were inhibited by eicosapentaenoic acid. These results suggest that the activities of both the proteasome and TPPII are regulated in a parallel manner in cancer cachexia, and that both are induced by the same factor and probably have the same intracellular signalling pathways and transcription factors.

Ephedrine is a sympathicomimetic agent that stimulates the central nervous and cardiovascular systems and causes bronchodilatation. It is one of the alkaloids in the herb Ephedra which is the basis of several over-the-counter herbal products, among which a number of popular weight-loss products. The Dutch Inspectorate for Health Care has received reports of adverse reactions presumably associated with Ephedra-containing weight-loss products. These adverse reactions comprised mainly palpitations, stress, headache and insomnia. The Ministry of Health in Canada has recently requested a market recall of some ephedrine-containing herbal products in response to a large number of adverse reactions reported in association with these products. The adverse reactions included stroke, heart attacks, cardiac arrhythmias, seizures and psychotic disorders. The voluntary recall concerns especially products that were marketed without approval and contain Ephedra in combination with caffeine or other stimulants. In the Netherlands, the status of Ephedra-containing products is currently reconsidered.

Thermogenesis and weight loss in obese individuals: a primary association with organochlorine pollution.

The main objective of this study was to investigate the potential impact of body organochlorine (OC) pollution on the adaptive change in thermogenesis induced by body weight loss. Fat mass (FM), fat-free mass (FFM), and sleeping metabolic rate (SMR) were measured in obese individuals before and after a weight-reducing program. The measured values of SMR were then compared to those predicted from a reference equation established from FM and FFM in control subjects. Plasma OC, leptin, total tri-iodothyronine, and free thyroxine concentrations were also measured in obese subjects before and after weight loss. After weight loss, the measured decrease in SMR was greater than that predicted by changes in FM and FFM. Increased plasma OC concentration was the factor explaining the greatest proportion of the difference between predicted and measured SMR changes induced by body weight loss. OC pollution seems to be a new factor affecting the control of thermogenesis in some obese individuals experiencing body weight loss.

Liver volume and visceral obesity in women with hepatic steatosis undergoing gastric banding.

OBJECTIVE: To investigate the relationships between visceral obesity and hepatic steatosis in obese patients undergoing adjustable silicone gastric banding with the LAP-BAND. RESEARCH METHODS AND PROCEDURES: Six premenopausal, morbidly obese women with an ultrasonographic diagnosis of liver steatosis were evaluated before surgery and 8 and 24 weeks after surgery. Liver volume and body fat distribution were simultaneously analyzed by total-body multislices magnetic resonance imaging. RESULTS: Before surgery, the only variable found to be correlated with liver volume was visceral adipose tissue volume (r = 0.91; p < 0.01). weight loss was 9.9 +/- 3.8 kg in the period from 0 to 8 weeks (p < 0.01) and 7.1 +/- 4.9 kg in the the period from 8 to 24 weeks (p < 0.05). Total fat showed a statistically significant reduction of 6.2 +/- 4.0 liters in the 0- to 8-week period and a further significant reduction of 7.7 +/- 3.9 liters in the 8- to 24-week period. Visceral adipose tissue showed a statistically significant reduction of 1.0 +/- 0.9 liters in the 0- to 8-week period (p < 0.05) but only a further, not significant reduction of 0.6 +/- 0.7 liters in the 8- to 24-week period. The relative reduction of visceral fat in the 0-to 8-week period was higher than the relative reduction of total fat. Liver volume also showed a statistically significant reduction of 0.24 +/- 0.26 liters in the first phase of weight loss (p < 0.05), corresponding to a relative reduction of 12.3 +/- 10.6%. During the 8- to 24-week period, liver volume was substantially stable. DISCUSSION: Hepatomegaly was associated with visceral obesity in morbidly obese women with liver steatosis. In the phase of rapid weight loss after gastric surgery, a preferential mobilization of visceral fat, compared with total adipose tissue, occurred. This preferential visceral fat loss was associated with a significant reduction in liver volume.

The effects of high protein diets on thermogenesis, satiety and weight loss: a critical review.

For years, proponents of some fad diets have claimed that higher amounts of protein facilitate weight loss. Only in recent years have studies begun to examine the effects of high protein diets on energy expenditure, subsequent energy intake and weight loss as compared to lower protein diets. In this study, we conducted a systematic review of randomized investigations on the effects of high protein diets on dietary thermogenesis, satiety, body weight and fat loss. There is convincing evidence that a higher protein intake increases thermogenesis and satiety compared to diets of lower protein content. The weight of evidence also suggests that high protein meals lead to a reduced subsequent energy intake. Some evidence suggests that diets higher in protein result in an increased weight loss and fat loss as compared to diets lower in protein, but findings have not been consistent. In dietary practice, it may be beneficial to partially replace refined carbohydrate with protein sources that are low in saturated fat. Although recent evidence supports potential benefit, rigorous longer-term studies are needed to investigate the effects of high protein diets on weight loss and weight maintenance.

Early mortality after radical radiotherapy for non-small-cell lung cancer: comparison of PET-staged and conventionally staged cohorts treated at a large tertiary referral center.

PURPOSE: At our center, approximately 30% of radical radiotherapy (RRT) candidates become ineligible for RRT for non-small-cell lung cancer (NSCLC) after positron emission tomography (PET). We hypothesized that early cancer death rates would be lower in patients receiving RRT after PET staging compared with conventionally staged patients. METHODS AND MATERIALS: Two prospective cohorts were compared. Cohort 1 consisted of all participants in an Australian randomized trial from our center given 60 Gy conventionally fractionated RRT with or without concurrent carboplatin from 1989 to 1995. Eligible patients had Stage I--III, Eastern Cooperative Oncology Group status 0 or 1, <10% weight loss, and had not undergone PET. Cohort 2 included all RRT candidates between November 1996 and April 1999 who received RRT after PET staging and fulfilled the above criteria for stage, Eastern Cooperative Oncology Group status, and weight loss. RESULTS: Eighty and 77 eligible patients comprised the PET and non-PET groups, respectively. The PET-selected patients had significantly less weight loss; 73% and 49% of the PET and non-PET patients, respectively, received chemotherapy. The median survival was 31 months for PET patients and 16 months for non-PET patients. Mortality from NSCLC and other causes in the first year was 17% and 8% for PET patients and 32% and 4% for non-PET patients, respectively. The hazard ratio for NSCLC mortality for PET vs. non-PET patients was 0.49 (p = 0.0016) on unifactorial analysis and was 0.55 (p = 0.0075) after adjusting for chemotherapy, which significantly improved survival. CONCLUSION: Patients selected for RRT after PET have lower early cancer mortality than those selected using conventional imaging.