La mantención de peso en humanos podría ser equivalente a la restricción calórica de los modelos animales? / Weight maintenance in humans. Could it mimic calorie restriction of animal models?

BACKGROUND: Energy restriction (ER) extends life span in animals, by decreasing oxidative stress. AIM: To compare adiposity, metabolic variables and DNA oxidative damage, among adults, reporting a constant body weight (weight maintainers), versus those reporting a progressive increase (weight gainers). SUBJECTS AND METHODS: Clinical history, dietary recall, anthropometric measures, abdominal CT scan and fasting blood samples (to measure lipoproteins, glucose and insulin), were obtained in 44 males. These subjects were classified as weight maintainers if they had a change in weight of 3 kg or less in the last 10 years, or weight gainers, if they had a weight increment of more than 6 kg, in the same lapse. Oxidative damage was assessed by 8-hydroxydeoxyguanosine (8-OHdG), in DNA extracted from circulating lymphocytes, in 5 weight maintainers, 8 weight gainers and 5 healthy elders. RESULTS: Energy Intake was 18% higher in weight gainers (p <0.01). Adiposity and central fat were higher among weight gainers (p <0.01). Abdominal fat correlated with serum lipoproteins, glucose and insulin sensitivity, assessed by the Homeostasis Model Assessment (HOMA). 8-OHdG levels did not differ between groups. CONCLUSIONS: The analysis of weight change based on the clinical history correlates with actual body composition, thus it may be a reliable indicator of long term energy Intake. This method could be comparable to weight clamp models employed in animals to study aging.

Evaluación de revascularización coronaria: comparación entre perfusión con Tc99m sestamibi-dipiridamol gatillado y ecografía-amrinona como predictores de viabilidad / Assessment of coronary revascularization: comparison between perfussion with Tc99m sestamibi-dipyridamol spect and echography-amrinone as predictors of viability

We studied left ventricular perfusion and motility in 37 patients with coronary artery disease and disturbances of parietal motility, aged 57 ñ 9 years old, before and after revascularization. Perfusion was assessed with dipyridamole-Tc99m SPECT and motility was assessed with 2 dimentional echocardiography with amrinone. Myocardial segments were defined as normal, viable or necrotic in both studies. Eighteen subjects were subjected to angioplasty and 19 to coronary bypass surgery. Submitted SPECT and echography were repeated 64 ñ 15 and 69 ñ 23 days after revascularization respectively. The concordance between SPECT and echocardiographic prerevascularization diagnosis was 60.1 percent. Eighty one percent of segment considered viable with SPECT and 71 percent thus considered with echocardiography improved after revascularization. Likewise, 50 percent of segments considered necrotic with SPECT and 68 percent of segment thus considered with echocardiography did not improve. It is concluded that althought there is a good concordance between both methods, they have limitations on the study of myocardial viability and should be considered as second choice