Using thermogravimetry for weight loss monitoring of permeation tubes used for generation of trace concentration gas standards.

Permeation tubes are convenient analyte sources for generating standard gas mixtures (containing, in particular, volatile organic compounds) used in the calibration of analytical instruments. For small permeation rates, corresponding to trace levels of analytes, the calibration of permeation tubes is time-consuming. The use of thermogravimetry as a means to measure rapidly the weight loss at constant temperature was investigated. An attempt to apply this technique to calibrating a permeation tube filled with benzene is described. In the 20 ng/min range of permeation rate, day-to-day variations of <5% were observed. The continuous weight loss monitoring of permeation tubes by thermogravimetry allows their rapid characterization.

Rising role of obesity surgery caused by increase of morbid obesity, failure of conventional treatments and unrealistic expectations: trends from 1997 to 2001.

BACKGROUND: The authors analyzed the trends in anthropometric and behavioral characteristics among patients seeking weight loss and the trends in choice of treatments, between 1997 and 2001 in an outpatient obesity clinic. PATIENTS AND METHODS: 138 and 128 consecutive patients attending the out-patient obesity clinic at University Hospital of Lausanne were screened in 1997 and in 2001 respectively. Eating habits, body composition and treatment used were assessed. RESULTS: Median BMI was 35 kg/m2 in 1997 and 38 kg/m2 in 2001 (P <0.001) and waist circumference was 99 cm and 111 cm respectively (P <0.001). This increase in the average body weight involved especially patients <30 years old (P <0.01). Morbid obesity increased by 16% (P <0.01), and prevalence of abdominal obesity by 13% (P < 0.05). The median desired weight loss increased significantly from 25% to 29% (P <0.05). 64% of the patients in 1997 and 83% in 2001 (P <0.01) hoped for a weight loss of 20% of their baseline weight. Motivation to lose weight for esthetic reasons was found in 81% of the women and 55% of the men in 1997 (P <0.01), while in 2001 the percentage was 89 and 43 respectively (P <0.001). CONCLUSION: In spite of the increasing access to weight loss programs, we found that the patients are more severely obese, especially those <30 years old, and have more unrealistic expectations of weight loss. This may explain the doubling of the patients treated by surgery.

Adiponectin before and after weight loss in obese children.

Adiponectin is decreased in obesity and seems to be involved in insulin resistance. The influences of age, gender, puberty, and weight loss on adiponectin have not been studied in obese children. We measured body fat mass based on skinfold thickness, age, pubertal stage, gender, adiponectin, and insulin resistance (homeostasis model assessment) in 42 obese children. We analyzed adiponectin and homeostasis model assessment 1 yr later in these obese children and separated them into two groups according to degree of weight loss (decrease in sd score for body mass index, >or=0.5 vs. <0.5). Adiponectin was negatively correlated to percentage body fat (r = -0.44; P = 0.002), insulin resistance (r = -0.33; P = 0.016), and age (r = -0.41; P = 0.003). Adiponectin levels were significantly (P = 0.017) higher in pubertal girls compared with boys, but there was no significant difference in prepubertal children in respect to gender (P = 0.833). Adiponectin was significantly (P < 0.001) lower in pubertal compared with prepubertal children. The significant weight loss in 16 children was associated with a significant increase in adiponectin (P = 0.010) and a decrease in insulin resistance (P = 0.013), whereas there were no changes in the 26 children without significant weight loss. Adiponectin levels in obese children were negatively correlated to age, body fat, and insulin resistance and were decreased in puberty. Significant weight loss led to an increase in adiponectin levels and an improvement of insulin resistance.

Education on the glycemic index of foods fails to improve treatment outcomes in a behavioral weight loss program.

The glycemic index (GI) may play an important role in weight management by helping to control appetite and insulin levels. The impact of adding education on the GI of foods to a behavioral weight loss program (BWLP) was examined. Fifty-three obese, sedentary participants were randomly assigned to receive either a BWLP or a BWLP+GI education. Pre- and posttreatment weight loss, body fat, and diet were assessed. weight loss and body fat were assessed at 1-year posttreatment. GI education had no significant impact on weight loss treatment outcomes at posttreatment or 1-year follow-up. Average weight loss was 7.6 kg (p<0.05). Participants in the BWLP+GI education group had significantly greater GI knowledge (p<0.05) and consumed foods with a lower average daily GI (p<0.05), than participants in the BWLP at posttreatment. At 1-year posttreatment, participants regained 59% of their posttreatment weight loss and 34% of their lost body fat. GI education did not improve BWLP treatment outcomes in this investigation.

Laparoscopic adjustable gastric banding: a prospective comparison of two commonly used bands.

BACKGROUND: Surgery for morbid obesity has increased since the introduction of the adjustable gastric bands (AGB), which can be placed laparoscopically. There are two AGB in wide use: the Swedish Adjustable Gastric Band (SAGB, Obtech), and the Lap-Band (Inamed Health). We present the results of a comparative study between the 2 AGB. METHODS: 101 patients with a minimal follow-up of 6 months were included. 49 patients received a Swedish Adjustable Gastric Band (SAGB), and the remaining 52 received the Lap-Band (LB). Postoperative weight loss and complications were compared at set intervals of 3 months in the first postoperative year, and 6 months in the years following. RESULTS: Mean follow-up was 9.9 months for the SAGB and 7.2 months for the LB. All but 5 procedures were performed laparoscopically. Mean operating-time was 102 minutes for the SAGB and 86 minutes for the LB. No significant difference in complications was noted between the 2 AGB. 1 SAGB was repositioned and 2 were removed, compared to 2 repositions and 2 removals of the LB. We excluded 5 patients with leakage of a SAGB due to technical failure. Mean preoperative weight kg/BMI of the SAGB patients was 133/45.3; in the LB patients 138/46.4. Mean weight loss at 6 months was 28 kg with the SAGB and 30 kg with the LB, and mean weight loss at 1 year 36 kg and 38 kg respectively. After 2 years, weight loss was 46 kg and 42 kg respectively. CONCLUSION: There was no significant difference in postoperative weight loss and complications between the SAGB and the LB.

Interest of pronostic score for optimal clinical management of obese patients.

OBJECTIVE: The aim of this retrospective study was to identify key factors favoring weight regain. METHODS: Therefore, prognostic factors for weight loss and regain have been retrieved and identified among 186 obese patients (40 +/- 2 y and 34 +/- 0.3 kg/m(2)) through the use of a simple questionnaire which considered psychological issues such as depression, anxiety and the patient's individual capacity to follow a diet. All patients have been prescribed a low-calorie diet (1200 kcal/day) being either balanced, food-combining or low-CHO. Follow-up averaged 6.4 +/- 0.3 months of which weight loss accounted for 4.4 +/- 0.1 months. RESULTS: weight loss was similar in all 3 groups and averaged 6.0 +/- 0.2 kg. The final weight loss and weight regain results have been identical for the 3 groups. A high/bad prognostic score rating is associated with weight regain (P<0.02). Weight regain is significantly influenced by the initial weight loss speed (P<0.0001). CONCLUSIONS: The proposed prognostic score is likely to be helpful for clinicians better to profile the therapeutic approach to individualized obesity management and follow-up. Diet composition does not influence either weight loss or weight regain.

Single-staged total body lift after massive weight loss.

This is a retrospective clinical report of a single-staged total body lift in 8 massive weight loss patients. While the combination of circumferential abdominoplasty, a modified lower body lift, and medial thighplasty adequately treats the lower torso and thighs, the residual skin laxity in the upper torso and breasts leaves an incomplete result. Hence, a 2-stage total body lift was designed. The second stage, called the upper body lift, removes epigastric and midback rolls of skin, adjusts the inframammary fold, and reshapes the breast or corrects gynecomastia, leaving behind a near circumferential transverse scar partially hidden by the breasts. In selected patients, a complete torso correction, the total body lift, was done in a single stage. Four to 31 months later, 7 of the 8 patients were satisfied. One male with ultrasonic-assisted lipoplasty and a lateral skin excision found the chest skin too loose. Blood transfusions ranged from none to 4 units. The operations range from 7 to 12 hours of general anesthesia. Hospital stays were from 3 to 4 days. The complications included 3 resolved seromas, 2 minor wound infections due to fat and skin necrosis, and 1 minor skin dehiscence. One patient was readmitted to the hospital due to hypoalbuminemia and generalized edema. Scar revisions and liposuction are scheduled for 2 patients. Single stage total body lift is effective and safe in selected patients after massive weight loss when performed by a plastic surgeon and team experienced in body contouring surgery.

Gastric bypass surgery in adolescents with morbid obesity.

OBJECTIVE: The objective was to review retrospectively all patients undergoing bariatric surgery at a large university medical center. METHODS: Ten adolescents 17 years or younger underwent gastric bypass surgery; 7 of 10 adolescents had severe obesity-related morbidities. Follow-up >1 year was present in 9 of 10 adolescents. RESULTS: The average weight before surgery was 148 +/- 37 kg. Postoperative recovery was uneventful in all adolescents; 9 of 10 adolescents had weight loss in excess of 30 kg (mean weight loss was 53.6 +/- 25.6 kg). obesity related morbidities resolved in all adolescents. Five adolescents had mild iron deficiency anemia, and 3 adolescents had transient folate deficiency. Late complications requiring operative treatment occurred in 4 of the adolescents. CONCLUSION: Gastric bypass surgery was an effective method for weight reduction in morbidly obese adolescents. The procedure was well tolerated, with few unanticipated side effects. Gastric bypass remains a last resort option for severely obese adolescents for whom other dietary and behavioral approaches to weight loss have been unsuccessful.