Exercise intolerance during post-MI heart failure in rats: prevention with supplemental dietary propionyl-L-carnitine

Exercise capacity in patients with several types of cardiovascular disease can be improved with dietary carnitine, or carnitine derivatives. Mechanisms underlying this improvement remain largely unknown in part due to a lack of animal models of cardiac pathology in which carnitine derivatives improve exercise tolerance. Our goal was to evaluate the ability of propionyl-L-carnitine (PLC) to improve exercise tolerance in a rat model of exercise intolerance. Fischer 344 rats were followed after either a moderate size MI (n = 22) or sham MI surgery (n = 14). Starting 10 days post-surgery 10 of the MI and 7 of the sham rats received 100 mg/kg/day PLC in drinking water, which increased plasma and LV total l-carnitine concentrations 15–23% (p < 0.05). Rats were followed longitudinally until a statistically significant decrease in exercise capacity occurred in one of the groups, at which time all rats were sacrificed for study of the isolated perfused hearts. At 12-weeks post-MI exercise capacity had decreased 16 ± 7% (p < 0.05) in the MI group, but remained within 3% of baseline in the MI group that received PLC and the sham groups. Both MI groups exhibited the same degree of LV dilation, decrease in fractional shortening, and blunting of the response to isoproterenol. We conclude that supplemental dietary PLC attenuates the exercise intolerance that occurs secondary to post-MI heart failure in rats, but that this beneficial effect is not attributable to altered LV remodeling, an improved response to -adrenergic stimulation, or increased skeletal muscle citrate synthase activity.     

Sleep apnoea caused by rheumatoid arthritis

Sleep apnoea syndrome (SAS) is a rarely documented, but possibly lethal, complication of the instability of the cervical spine in rheumatoid arthritis. Five patients with SAS of a central or peripheral origin are presented, and the problems of recognizing and diagnosing the syndrome are discussed. We hope that clinicians will become more aware of the existence and the different aetiologies of SAS, thus improving early recognition and appropriate treatment. Adequate treatment has proven to increase survival in peripheral SAS and seems to be successful in doing so in central SAS.      

Reduction of patient exposure by use of heavy elements as radiation filters in diagnostic radiology

The effect on patient exposure of x-ray filters made of heavy elements has been studied in excretory urography and lumbar spine examinations. Several elements with atomic numbers between 62 and 74 were tested in experiments using radiographic phantoms and in patient studies. A holmium filter reduced skin exposure by more than 50% in excretory urography. Similar results were obtained with ytterbium and tungsten in lumbar spine studies.