No abstract

IntroductIonBariatric surgery is quickly emerging as a standard treatment for severely obese (BMI ≥40 kg/m 2 ) individuals, because of its significant long-term effects on body weight, obesity-related comorbidities and health-related quality of life (HRQoL) (1-3). Surgical success, however, is dependent on more than the procedure that is employed and the proficiency with which a particular technique is performed. Several nonsurgical factors including demographic and weight-related characteristics, eating patterns, and psychosocial factors may contribute to variability in postoperative weight loss and HRQoL improvement (4-6). Yet, little is known about whether changes in behaviors, particularly physical activity (PA), following bariatric surgery promote enhanced weight loss and HRQoL improvements in this population.Cross-sectional studies suggest that postoperative PA is associated with enhanced weight loss and maintenance following bariatric surgery (7-11). Two studies comprising samples of >1,000 patients-one conducted in the United States following Roux-en-Y gastric bypass (RYGB) and the other in France following laparoscopic adjustable gastric banding (LAGB)-found that categorical endorsement of participation in regular PA postoperatively was related to better weight loss maintenance at 2 years postoperatively (8,11). More recently, postoperative participation in ≥150 min of moderate-vigorous intensity activity, as assessed by the International Physical Activity Questionnaire (IPAQ), was shown to be associated with greater weight loss and BMI change at both 6 months and 1 year following RYGB (10). This study, however, did not include walking in the assessment of PA. In addition, this study was cross-sectional and consequently does not provide any information about pre to postoperative changes in PA.Few prospective studies have assessed pre-to postoperative changes in PA among bariatric surgery patients. In these studies (9,12,13), the proportion of patients reporting participation

A previous study (Grassi B, Gladden LB, Samaja M, Stary CM, and Hogan MC, J Appl Physiol 85: 1394-1403, 1998) showed that convective O(2) delivery to muscle did not limit O(2) uptake (VO(2)) on-kinetics during transitions from rest to contractions at approximately 60% of peak VO(2). The present study aimed to determine whether this finding is also true for transitions involving contractions of higher metabolic intensities. VO(2) on-kinetics were determined in isolated canine gastrocnemius muscles in situ (n = 5) during transitions from rest to 4 min of electrically stimulated isometric tetanic contractions corresponding to the muscle peak VO(2). Two conditions were compared: 1) spontaneous adjustment of muscle blood flow (Q) (Control) and 2) pump-perfused Q, adjusted approximately 15-30 s before contractions at a constant level corresponding to the steady-state value during contractions in Control (Fast O(2) Delivery). In Fast O(2) Delivery, adenosine was infused intra-arterially. Q was measured continuously in the popliteal vein; arterial and popliteal venous O(2) contents were measured at rest and at 5- to 7-s intervals during the transition. Muscle VO(2) was determined as Q times the arteriovenous blood O(2) content difference. The time to reach 63% of the VO(2) difference between resting baseline and steady-state values during contractions was 24.9 +/- 1.6 (SE) s in Control and 18.5 +/- 1.8 s in Fast O(2) Delivery (P < 0.05). Faster VO(2) on-kinetics in Fast O(2) Delivery was associated with an approximately 30% reduction in the calculated O(2) deficit and with less muscle fatigue. During transitions involving contractions at peak VO(2), convective O(2) delivery to muscle, together with an inertia of oxidative metabolism, contributes in determining the VO(2) on-kinetics.

Two hundred eighty-one patients with the acquired immunodeficiency syndrome (AIDS) or advanced AIDS-related complex were enrolled in a double-blind, placebo-controlled trial of the efficacy and safety of orally administered zidovudine (azidothymidine or AZT). Significant clinical benefits and adverse experiences have been reported from this trial. Because neuropsychiatric dysfunction is often associated with human immunodeficiency virus (HIV) infection, a brief affective and neuropsychological examination was administered over 16 weeks of the trial to evaluate any changes in neuropsychological function that occurred with drug administration. Patients receiving zidovudine, particularly those with AIDS, showed improved cognition as compared with patients receiving placebo. There were no changes in affective symptoms. The zidovudine recipients also had a statistically significant reduction in the intensity of symptomatic distress during the trial that may account in part for the observed cognitive changes. Some improvement in various cognitive measures was also seen in patients with AIDS-related complex. The results of this study suggest HIV-associated cognitive abnormalities may be partially ameliorated after the administration of zidovudine.

The data demonstrate that relatively modest hypohydration ( approximately 2.7%) as a result of EID, significantly slows 5- and 10-m sprint times. Furthermore, although the glycerol hydration regimen provided a better hydration status than the placebo hydration regimen, no performance benefits were observed.