Pancreatin enhanced erosion of and macromolecule release from 2,2-bis(2-oxazoline)-linked poly(epsilon-caprolactone).

The degradation and erosion of solvent cast films and injection molded bars prepared from poly(epsilon-caprolactone) (PCL) and 2,2'-bis(2-oxazoline) linked poly(epsilon-caprolactone) (PCL-O) were evaluated in simulated gastric fluid (SGF) (pH 1.2, pepsin present) and in simulated intestinal fluid (SIF) (pH 7.5, pancreatin present). After incubation of the polymer films (10 mg) and bars (70 mg) in the medium, the resulting decrease in molecular weight (degradation) was determined by size exclusion chromatography and the weight loss of the preparations was measured. In addition, the effect of pancreatin on FITC-dextran (MW 4400) release from PCL and PCL-O microparticles, prepared by w/o/w double emulsion technique, was studied. No degradation or weight loss was observed for either PCL or PCL-O films in SGF (12 h incubation, 37 degrees C). When compared to PBS pH 7.4, pancreatin hardly enhanced the weight loss of PCL films and bars. In contrast, pancreatin enhanced substantially erosion of PCL-O films and bars. Unlike PCL preparations, the PCL-O preparations showed surface erosion in SIF. Pancreatin increased considerably FITC-dextran release from both PCL and PCL-O microparticles. In conclusion, the present results demonstrate the enzyme sensitivity of the novel PCL-O polymer. In addition, the results show that pancreatin present in intestinal fluid may substantially affect drug release from PCL based preparations.

Combat rations and military performance - do soldiers on active service eat enough?

Background - Defence food technology aims to provide an easy-to-prepare and palatable, nutritionally complete combat ration pack (CRP) which has minimal weight and volume and maximum shelf life under all climatic extremes. The nutritional aims are to identify the optimal nutrient mix to sustain the soldier in the face of operational stressors such as fatigue, intense physical activity, extreme climate and negative psychological factors and to encourage consumption. Review - Two studies of CRP consumption, which differed in duration and design, were conducted recently by DSTO Scottsdale. The first study was conducted in far northern Australia over 12 days during a routine patrol-training exercise and the second in the jungle of Sabah, Malaysia for 23 days of adventure training. In the first study three groups received either: freshly prepared foods (fresh group, 15 MJ, n=13), full CRP (15 MJ, n=10) or half CRP (7.5 MJ, n =10). Under consumption by the full CRP group resulted in CRP groups experiencing similar weight loss (mean of 3%), protein catabolism and immune suppression while the fresh group maintained their weight and protein balance and cell-mediated immune status. CRP groups reported greater fatigue than the fresh group. All soldiers experienced poor sleep quality and declining folate and iron status, but no decrement in physical fitness or cognition. In the second study soldiers who were involved in building walking tracks (Tawau Hills, n=20) and tree-top observation platforms (Danum Valley, n= 11) were fed with CRP (Tawau Hill group) or fresh meals (Danum Valley group). Soldiers were able to self-select their food from available supplies. Soldiers supplied with CRP ate between 0.8 and 1.3 packs per day. After 23 days mean weight loss of both groups was 5.5%, there were no decrements in physical and mental performance and good immune status was maintained. Food consumption was encouraged by, the novelty of new foods, ability to socialise and take meal breaks, ability to self-select food items and number of serves, adequate sleep, good morale, and good hydration status. Conclusions - On the positive side these studies indicate that adaption to reduced energy intake (of up to 50% of estimated requirement) is shown over the short-medium term so that there is no detriment to physical and cognitive performance and that when the entire CRP is consumed (ie around 15MJ per day) soldiers can maintain moderate to hard physical activity for 3 weeks without loss of physical fitness, immune function or cognitive ability. On the negative side the studies revealed that significant although small weight loss can be expected after only 12 days of feeding with CRP and that CRP feeding is associated with increased fatigue, mild immune suppression, loss of body protein, decreased stores of antioxidants, folic acid, vitamin B6, vitamin K and iron.

Self-help and long-term behavior therapy for obesity.

The Trevose Behavior Modification Program, a self-help group offering continuing care for obesity, has recently been shown to produce large long-term weight losses. The present study aimed to replicate this finding across different settings and participants, assessing the weight losses and attrition rates of 128 participants in three Trevose program satellite groups that used the same treatment procedures and manual as the central Trevose group. The satellite groups' results closely paralleled those of the Central Group. Mean intent-to-treat weight loss, or final losses recorded for all participants regardless of their treatment termination date, was 13.7 +/- 0.7% of initial body weight (1.8 +/- 0.7 kg). At two years, 43.8% of participants remained in treatment, having lost a mean of 19.0 +/- 0.8% of their body weight (16.2 +/- 1.0 kg); at five years, 23.4% remained, having lost 18.4 +/- 1.1% of body weight (15.6 +/- 1.5 kg). These results demonstrate that the Trevose model of weight control, combining self-help and continuing care, can be extended and disseminated to other settings, with potentially significant public health consequences.

Hepatic injury in 12 patients taking the herbal weight loss AIDS Chaso or Onshido.

BACKGROUND: The Chinese herbal dietary supplements Chaso and Onshido are marketed for weight loss in Japan. The safety of these weight loss aids is unknown. OBJECTIVE: To describe patients who developed liver injury while taking Chaso or Onshido. DESIGN: Case series. SETTING: Keio University Hospital, Tokyo, Japan, and other hospitals in Japan. PATIENTS: 6 patients who took Chaso and 6 patients who took Onshido before presenting with liver injury. MEASUREMENTS: Pathologic, clinical, and laboratory evaluations and chemical analysis of the herbal weight loss aids. RESULTS: All 12 patients developed acute liver injury characterized by a marked increase in serum liver chemistry values (mean alanine aminotransferase level, 1978 U/L [range, 283 to 4074 U/L]) after ingesting these products. Two patients developed fulminant hepatic failure: 1 patient required liver transplantation, and the other patient died. N-nitroso-fenfluramine, a variant of the appetite-depressant drug fenfluramine, was present in these products. CONCLUSIONS: The use of the weight loss aids Chaso and Onshido may be associated with acute liver injury. N-nitroso-fenfluramine is a possible hepatotoxic ingredient.

Differences in mechanisms between weight loss-sensitive and -resistant blood pressure reduction in obese subjects.

This study was conducted to clarify the mechanisms involved in the sensitivity for blood pressure (BP) reduction in response to weight loss. In particular, we focused on the contributions of sympathetic nervous system activity and fasting plasma leptin and insulin levels to BP levels during weight loss in obese subjects with weight loss-sensitive and -resistant BP reduction. Sixty-one young, obese untreated hypertensive men (HT) and 52 obese normotensive men (NT) were enrolled in a weight loss program consisting of a low caloric diet and aerobic exercise over a 24-week period. At entry and at week 24, body mass index (BMI), BP, plasma norepinephrine (NE), leptin and insulin were measured. Successful weight loss and BP reduction were respectively defined as a more than a 10% reduction in BMI or mean BP from baseline at week 24. More than 60% of subjects in either group successfully achieved weight loss by this definition. The percentage of subjects who successfully achieved BP reduction was higher (64%) among those subjects who achieved weight loss than among those who did not (22%). Plasma NE level at entry in subjects who failed to achieve BP reduction despite weight loss was significantly higher than that in subjects who succeeded in BP reduction. Plasma leptin and insulin levels were similar between subjects with and without BP reduction. In addition, the absolute decrement and percent decrement in plasma NE in subjects who succeeded in BP reduction were significantly greater than those in subjects who failed to reduce their BP. Absolute and percent decrements in plasma leptin and insulin were similar in both groups. These results suggest that individuals who are resistant to weight loss-induced BP reduction have more sympathetic overactivity both at the outset of and during weight loss.

Gastric bypass in a low-income, inner-city population: eating disturbances and weight loss.

OBJECTIVE: To examine the prevalence of eating disturbances and psychiatric disorders among extremely obese patients before and after gastric bypass surgery and to examine the relationship between these disturbances and weight outcomes. RESEARCH METHODS AND PROCEDURES: Sixty-five women patients (ages 19 to 67) with a mean BMI of 54.1 were assessed by semistructured psychiatric interview before surgery and by telephone interview after surgery (mean follow-up: 16.4 months) to determine psychiatric status, eating disturbances, and weight and health-related variables. RESULTS: Patients lost a mean of 71% of their excess BMI, with significantly poorer weight loss outcomes among African Americans. Psychiatric disorders remained prevalent before (37%) and after (41%) surgery. In contrast, binge eating disorder dropped from 48% to 0%. Psychiatric diagnosis did not affect weight outcomes. Instead, more frequent preoperative binge eating, along with greater initial BMI, follow-up length, and postoperative exercise, predicted greater BMI loss. Postsurgical health behaviors (exercise and smoking) and nocturnal eating episodes were also linked to weight loss. Exercise frequency increased and smoking frequency tended to decrease after surgery. DISCUSSION: These findings indicated that eating and psychiatric disturbances did not inhibit weight loss after gastric bypass and should not contraindicate surgery. Prior binge eating, eliminated after surgery, predicted BMI loss and, thus, may have previously been a maintaining factor in the obesity of these patients. The association between health behaviors and outcome suggests possible targets for intervention to improve surgical results. Poorer outcomes among African Americans indicate that these patients should be closely monitored and supported after surgery.

Laparoscopic reoperative bariatric surgery: experience from 27 consecutive patients.

BACKGROUND: 10 to 25% of patients undergoing bariatric surgery will require a revision, either for unsatisfactory weight loss or for complications. Reoperation is associated with a higher morbidity and has traditionally been done in open fashion. The purpose of this study was to determine the safety and efficacy of reoperative surgery using a laparoscopic approach. METHODS: A retrospective review of medical records over a 22-month period was conducted. 27 consecutive obesity surgery patients, who had undergone a laparoscopic revision, were identified. 26 of the 27 patients were women. The average age was 40.3 years (range 20 to 58 years) and average original preoperative body mass index (BMI) was 51.6 kg/m2 (range 42 to 66.5). The 27 primary bariatric operations consisted of vertical banded gastroplasty (12), gastric band placement (9) and gastric bypass (6). 17 of them were open procedures. After the primary surgery, the lowest average BMI was 37.6 kg/m2 (range 21 to 52), which increased to 42.7 kg/m2 (range 29 to 56) before reoperation. 24 of the 27 reoperations were indicated for insufficient weight loss. On average, revision was undertaken 52 months after the primary procedure (range 12 to 240 months). RESULTS: 24 of the 27 laparoscopic reoperations were conversions to a gastric bypass. A second reoperation was indicated for insufficient weight loss on four occasions. In one case, conversion to open surgery was required. The average operative time was 232 +/- 18.5 minutes (range 120 to 480) and length of hospital stay was 3.7 days (range 1 to 9). 22% percent of patients (6) experienced complications, including pneumothorax, gastric remnant dilation, gastrojejunostomy stenosis, port-site hernia and protein malnutrition. There was no mortality in the study. The average BMI was 35.9 kg/m2 (range 27 to 45.5) 8 months after surgery (range 1 to 22 months). Compared with a preoperative BMI of 42.7 kg/m2, the weight loss was statistically significant (p < 0.001). CONCLUSION: Our results compare favorably with those reported for open reoperative bariatric surgery. A laparoscopic approach may be considered a feasible and safe alternative to an open operation.

Effect of a high-protein, energy-restricted diet on body composition, glycemic control, and lipid concentrations in overweight and obese hyperinsulinemic men and women.

BACKGROUND: It is not clear whether varying the protein-to-carbohydrate ratio of weight-loss diets benefits body composition or metabolism. OBJECTIVE: The objective was to compare the effects of 2 weight-loss diets differing in protein-to-carbohydrate ratio on body composition, glucose and lipid metabolism, and markers of bone turnover. DESIGN: A parallel design included either a high-protein diet of meat, poultry, and dairy foods (HP diet: 27% of energy as protein, 44% as carbohydrate, and 29% as fat) or a standard-protein diet low in those foods (SP diet: 16% of energy as protein, 57% as carbohydrate, and 27% as fat) during 12 wk of energy restriction (6-6.3 MJ/d) and 4 wk of energy balance ( approximately 8.2 MJ/d). Fifty-seven overweight volunteers with fasting insulin concentrations > 12 mU/L completed the study. RESULTS: weight loss (7.9 +/- 0.5 kg) and total fat loss (6.9 +/- 0.4 kg) did not differ between diet groups. In women, total lean mass was significantly (P = 0.02) better preserved with the HP diet (-0.1 +/- 0.3 kg) than with the SP diet (-1.5 +/- 0.3 kg). Those fed the HP diet had significantly (P < 0.03) less glycemic response at weeks 0 and 16 than did those fed the SP diet. After weight loss, the glycemic response decreased significantly (P < 0.05) more in the HP diet group. The reduction in serum triacylglycerol concentrations was significantly (P < 0.05) greater in the HP diet group (23%) than in the SP diet group (10%). Markers of bone turnover, calcium excretion, and systolic blood pressure were unchanged. CONCLUSION: Replacing carbohydrate with protein from meat, poultry, and dairy foods has beneficial metabolic effects and no adverse effects on markers of bone turnover or calcium excretion.