Prosthetic aortic valve endocarditis due to Stenotrophomonas maltophilia complicated by subannular abscess.

Annular abscesses are serious complications of infectious native and prosthetic valve endocarditis. In this patient, we isolated Stenotrophomonas maltophilia, a rare cause of subaortic abscess with high mortality/morbidity rates although virulent gram-positive cocci, S. Aureus in particular, have been the most commonly isolated agents. We treated this case of endocarditis and the subannular abscess observed 1 year after the initial operation by aortic root replacement with resternotomy in addition to appropriate antibiotics.

Influence of a liquid diet and meal pattern on body weight and body fat in rats.

Rats weighing 110 to 150 g or 250 g initially were utilized in five experiments to determine the effect of the form of the diet (dry versus liquid) and the pattern of feeding (meal-feeding, force-feeding, nibbling, or ad libitum) on body weight gain and on body fat. A high-carbohydrate, 20% casein or 20% lactalbumin diet was fed for 4 to 8 weeks. Consumption of a diet mixed with an equal weight of water increased weight gain in one of three experiments. Body fat content of the rats was not influenced by addition of water to the diet. Neither force-feeding nor meal-feeding influenced body fat gain provided the respective control rats were pair-fed during the initial adaptation period. Likewise, when rats were pair force-fed to ad libitum fed rats without an initial adaptation meal frequency did not influence body fat gain. When meal-fed rats were switched to ad libitum intake their food intake increased to equal that of rats which had been continuously fed ad libitum; however, the rats which had been switched gained more body fat than did rats continuously fed ad libitum. These results suggest that meal frequency may have a minimal influence on body fat accumulation, but that a shift to a higher level of food intake may cause an increased food efficiency and greater rate of fat deposition than in rats continuously fed the higher level of intake.

Influence of diet composition on nitrogen balance and body composition in meal-eating and nibbling rats.

A series of experiments was conducted to evaluate the influence of meal frequency on nitrogen balance and body composition of rats. Rats were either fed 2 hours per 24 or 48 hours (meal-eaters), or pair-fed to meal-eaters with an automated feeding machine (nibblers). Rats weighing approximately 250 g initially, were fed 10%, 20%, or 30% casein, high-carbohydrate diets or a 20% casein high-fat diet for 7 to 8 weeks. Meal-eaters gained essentially the same amount of body weight as the nibblers. Meal-feeding once per 24 or 48 hours did not adversely influence nitrogen balance or the body composition of the rats. In one experiment, smaller rats, weighing approximately 150 g initially, were utilized. Meal-eaters again, retained as much nitrogen as nibblers, and contained less body fat than the nibblers. In these studies, meal-eating did not cause a depression in nitrogen retention or an increase in body fat deposition in rats.