Dietary-induced thermogenesis in obesity. Response to mixed and carbohydrate meals

Summary The possibility that dietary-induced thermogenesis may be decreased in obesity has been proposed in recent years. However, the results of human studies so far obtained are conflicting. The present research was undertaken in order to clarify this question. We studied postprandial thermogenesis induced by ingestion of a mixed meal and of a carbohydrate mixture in 15 normal and 12 obese subjects. Blood glucose and plasma insulin levels were measured at the same time. The data obtained have shown that the mean resting metabolic rate (RMR) expressed as a function of body weight^3/4, is almost the same in obese as in normal-weight subjects (0.115±0.018vs 0.133±0.021 kj/min/kg^3/4, respectively). Moreover, the increment of mixed-meal induced thermogenesis (MM-IT) was 48±22% in normal and −0.8±12% in obese subjects, respectively (p<0.01). Carbohydrate induced thermogenesis (CHO-IT) appeared slightly higher in normal-weight than in obese subjects (159±66vs 98±46). After carbohydrate ingestion we observed a higher glycemic and insulinemic response in obesity. These results indicate that thermogenesis induced by ingestion of food is reduced in obese subjects; they are also compatible with the idea that insulin resistance could play a role in this phenomenon.     

Paradoxical embolisation of a catheter fragment to a coronary artery in an infant with congenital heart disease.

Six weeks after cardiac catheterisation via the right femoral vein an infant underwent an anatomical correction for transposition of the great vessels and closure of a large ventricular septal defect. The patient died intraoperatively as a result of severe left ventricular dysfunction. Necropsy showed an old myocardial infarction associated with thrombosis of the circumflex coronary artery. Electron probe x ray analysis showed that foreign refractile material within the thrombus contained bismuth, an element used in the construction of some cardiac catheters. This is believed to be the first report of "paradoxical" coronary embolisation of catheter-derived material and highlights the usefulness of electron probe x ray analysis.     

Regional patterns of brain metabolites in AIDS dementia complex

The relationship of the cellular changes in the HIV-infected brain to the onset and progression of AIDS dementia complex (ADC) remains uncertain. We undertook an in vivo proton magnetic resonance spectroscopy (MRS) study and used factor analysis to identify specific cellular and regional brain changes that may serve as metabolic markers of ADC. The ratio of N-acetyl aspartate (NAA), choline (Cho), and myoinositol (MI) over creatine (Cr), markers of neuronal and glial cell metabolism, were measured in the basal ganglia, centrum semiovale, and parietal cortex from 100 subjects with and without ADC. Three metabolic patterns were identified, which we termed "inflammatory" (mainly MI/Cr elevations in all three regions plus Cho/Cr increases in the centrum semiovale and parietal cortex), "basal ganglia" (mostly NAA/Cr and Cho/Cr elevations in the basal ganglia), and "neuronal" (primarily NAA/Cr reductions in the centrum semiovale and the parietal cortex). Logistic regression analysis revealed that, adjusted for age, basal ganglia and neuronal pattern scores were strongly associated with ADC but inflammatory levels were not. We conclude that by using factor analysis, we are able to combine multiple metabolites across brain regions in a biologically plausible manner and construct a predictive model of ADC adjusting for relevant factors such as age.     

Compression and venous surgery for venous leg ulcers

This article reviews published data on the effects of surgery and compression in the treatment of venous ulcers and the best options for compression therapy. Randomized controlled studies reveal that surgery and compression have similar effectiveness in healing ulcers but surgery is more effective in preventing recurrence. Most leg ulcers have a venous pathophysiology and occur because of venous ambulatory hypertension caused by venous reflux and impairment of the venous pumping function. Proposed surgical interventions range from crossectomy and stripping to perforator vein interruption and endovascular procedures (laser, radiofrequency). More conservative procedures (foam sclerotherapy, conservative hemodynamic treatment) have also been proposed.