Comprehensive nutrition and lifestyle education improves weight loss and physical activity in Hispanic Americans following gastric bypass surgery: a randomized controlled trial

BackgroundAs morbid obesity increasingly affects Hispanic Americans, the incidence of bariatric procedures among this population is rising. Despite this, prospective research on the effects of comprehensive postoperative education-centered interventions on weight loss and physical activity focused on Hispanic Americans is lacking.ObjectiveTo examine whether a comprehensive nutrition education and behavior modification intervention improves weight loss and physical activity in Hispanic Americans with obesity following Roux-en-Y gastric bypass surgery (RYGB).MethodsA prospective randomized-controlled trial was conducted between November 2008 and April 2010. At 6 months following RYGB, 144 Hispanic Americans with obesity were randomly assigned to a comprehensive nutrition and lifestyle educational intervention (n=72) or a noncomprehensive approach (comparison group n=72). Those in the comprehensive group received education sessions every other week for 6 weeks in small groups and frequent contact with a registered dietitian. Those in the comparison group received brief, printed healthy lifestyle guidelines. Patients were reassessed at 12 months following surgery. Main outcome measures were excess weight loss and physical activity changes over time. Statistical analyses used t test, χ² test, Wilcoxon signed rank, Mann-Whitney U test, and intent-to-treat analysis, significance P<0.05.ResultsParticipants (mean age 44.5±13.5 years) were mainly Cuban-born women (83.3%). Mean preoperative excess weight and body mass index (calculated as kg/m²) were 72.20±27.81 kg and 49.26±9.06, respectively. At 12 months following surgery, both groups lost weight significantly, but comprehensive group participants experienced greater excess weight loss (80% vs 64% from preoperative excess weight; P<0.001) and greater body mass index reduction (6.48±4.37 vs 3.63±3.41; P<0.001) than comparison group participants. Comprehensive group participants were significantly more involved in physical activity (+14 min/wk vs ?4 min/wk; P<0.001) than comparison group participants. Mean protein intake was significantly lower in the comparison group than that in the comprehensive group (P<0.024).ConclusionsFindings support the importance of comprehensive nutrition education for achieving more effective weight reduction in Hispanic Americans following RYGB.     

Hepatocyte ultrastructure in rats with portacaval shunt

The principal reported morphological consequence of portacaval shunt in the rat is liver atrophy. The present study was designed to investigate ultrastructural changes in hepatocytes using electron microscopy morphometry. Two weeks following portacaval shunt, rat livers were fixed by perfusion and hepatocyte organelles from the two opposite zones of the acinus (zones 1 and 3) were quantified. Liver weight/body weight decreased by 50%, hepatocyte-specific volume decreased by 30% (28% in zone 1 and 35% in zone 3). Estimated sinusoidal space increased, and estimated number of hepatocytes decreased by 50%. Hepatocytes had a normal ultrastructure except for mitochondria. Smooth endoplasmic reticulum-specific surface area was reduced by 65% (zone 3), and rough endoplasmic reticulum surface density was increased in zone 1 only. Mitochondriaspecific volume was unchanged but decreased inner and outer membrane-specific surface area in zone 3 suggests in this zone a change in their conformation and possibly their number. Golgi-rich area surface density increased but not significantly. Hepatocyte loss and atrophy and rearrangement of organelles represent a new ultrastructural steady state following portacaval shunt that may help explain the new functional steady state.     

The effects of losartan compared to atenolol on stroke in patients with isolated systolic hypertension and left ventricular hypertrophy. The LIFE study

The Losartan Intervention For Endpoint reduction in hypertension (LIFE) study reported that a losartan-based antihypertensive regimen reduced cardiovascular morbidity and mortality (composite of cardiovascular death, stroke, and myocardial infarction) more than therapy based on atenolol in patients with left ventricular hypertrophy and isolated systolic hypertension (ISH). Patients aged 55-80 years with blood pressures 160-200/<90 mm Hg were followed for a mean of 4.7 years. Blood pressure was similarly reduced in the losartan (n=660) and atenolol (n=666) ISH groups. There were 88 (6.6%) patients who experienced a stroke, 18 of which were fatal. Of patients experiencing strokes, 72.7% had an ischemic stroke. ISH patients in LIFE compared to the non-ISH group had a higher incidence of any stroke and embolic stroke, and similar incidences of fatal, atherosclerotic, and hemorrhagic/other strokes. The incidence of any stroke (40% risk reduction [RR], p=0.02), fatal stroke (70% RR, p=0.035), and atherothrombotic stroke (45% RR, p=0.022) was significantly lower in losartan-treated compared to the atenolol-treated patients. The 36% RR for embolic strokes in the losartan group was not statistically significantly (p=0.33) different from the atenolol group. These data suggest that losartan-based treatment is more effective than an atenolol-based treatment for patients with ISH and a high risk for stroke.     

The significance of platelet-vessel wall prostaglandin equilibrium during exercise-induced stress

Alterations in platelet-generated thromboxane A₂ (TXA₂) and vessel wall-generated prostacyclin (PGI₂) have been assoclated with myocardial ischemia. To examine TXA₂ - PGI₂ equilibrium at rest and during exercise stress, we studied 13 normal subjects and 15 coronary artery disease patients. Plasma TXB₂ and 6-keto-PGF_1α were measured as stable metabolites of TXA₂ and PGI₂, respectively, by radioimmunoassay. In normal subjects, plasma TXB₂ levels increased 24% during exercise from 135 ± 30 to 168 ± 42 pg/ml (p = NS). Plasma 6-keto-PGF_1α levels increased 224% from 54 ± 17 to 175 ± 57 pg/ml (p < 0.05). In coronary artery disease patients, although resting plasma TXB₂ levels (mean 136 ± 43 pg/ml) were comparable to levels in normal subjects, a greater increase (82%) occurred during exercise (mean 248 ± 70 pg/ml; p < 0.02 compared to resting levels). Resting plasma 6-keto-PGF_1α levels (mean 94 ± 28 pg/ml) were also similar to normal subjects but increased only by 43% during exercise (mean 134 ± 53 pg/ml; p = NS compared to resting levels). These data suggest that: in normal subjects TXA₂ and PGI₂ increase during exercise, PGI₂ increasing more than TXA₂, and although coronary disease patients have resting TXA₂ and PGI₂ levels in the normal range, TXA₂ levels increase more than PGI₂ levels during exercise. These observations may have a bearing on the mechanism of exercise-induced angina pectoris in certain coronary artery disease patients.