Different Location of Triaxial Accelerometer and Different Energy Expenditures

PURPOSE: We performed a study to determine the best appropriate wearing site of a triaxial accelerometer at different exercise speeds. MATERIALS AND METHODS: We conducted an observational study with 66 healthy Korean adults (26 men and 40 women). Resting metabolic rate (RMR) before exercise, physical activity-related energy expenditure (PAEE) by cardiorespiratory gas analyzer and Signal Vector Magnitude (SVM) were measured while wearing four triaxial accelerometers on four different sites (wrist, waist, upper arm, and ankle) at exercise speeds from 2-10 km/h. RESULTS: The mean RMR was 4.03 mL/kg/min and Actual METs (oxygen consumption at different exercise speeds divided by individual RMR) compared with the calculated METs (oxygen consumption divided by 3.5 mL/kg/min) showed relatively low value. The overall correlation between PAEE and SVM was highest when the accelerometer was worn on the wrist at low exercise speed (r=0.751, p<0.001), waist at a moderate speed (r=0.821, p<0.001), and ankle at a high speed (r=0.559, p<0.001). Using regression analysis, it was shown that the ankle at a low speed (R2=0.564, p<0.001), high speed (R2=0.559, p<0.001), and the waist at a moderate speed (R2=0.821, p<0.001) were the best appropriate sites. CONCLUSION: When measuring the PAEE and SVM at different exercise speeds, the ankle in low and high exercise speed, and waist in moderate speed are the most appropriate sites for an accelerometer.

The Effect of Enalapril on the Peak Rates of Left Ventricular Wall Movement in Patients with Dilated Cardiomyopathy / 대한내과학회지

OBJECTIVE: Angiotensin-converting enzyme inhibitors have been shown to improve survival in patients with congestive heart failure. To evaluate the efficacy of enalapril in patients with dilated cardiomyopathy during concurrent treatment with digoxin and diuretics, the peak rates of left ventricular movement were assessed after 6 months of follow-up by digitized echocardiography. METHODS: Using a high quality digitizer, continuous measurement of left ventricular dimension and its rate of change (dD/dt) were obtained throughout the cardiac cycle. Normalized rates of wall movement (dD/dt/D) were used for comparison. RESULTS: 1) Compared with control subjects, patients with dilated cardiomyopathy showed much lower Peak(-) dD/dt and Peak(-) dD/dt/D. 2) Peak(+) dD/dt and Peak(+) dD/dt/D were also depressed in patients. 3) Peak dD/dt improved significantly (p<0.05) in the enalapril group (n=16), but did not change in the conventional treatment group (n=20) after 6 months. Peak dD/dt/D improved approximately (p<0.005) in the enalapril group. 5) There were no deaths in 2 treatment groups during initial 6 months, but 3 patients in the conventional treatment group died suddenly during 1 year of follow-up. CONCLUSION: The present study has shown that left ventrieular Peak dD/dt and Peak dD/dt/D are significantly depressed in patients with dilated cardiomyopathy. Enalapril appears to provide well-tolerated and effective long-term therapy by improving peak rates of left ventricular movement in patients with dilated cardiomyopathy.

Ultrastructural Changes of the Aorta in Spontaneously Hypertensive Rats and the Effect of High Cholesterol Diet

BACKGROUND: Vascular lesions are the major cause of morbidity and mortality in hypertensive patients. However, the pathologic characteristics of gradually evolving, chronic hypertension have not been adequately studied and the mechanism by which hypertension accelerates atherosclerosis is still uncertain. This study was undertaken to invertigate the ultrastructural changes of the aorta and the effect of high cholesterol diet in spontaneously hypertensive rats(SHR). METHODS: Spontaneously hypertensive rats (n=80, male, 5 weeks old) and Wistar rats (n=40, male, 5 week old) were used. Forty SHR were fed with 2% cholestrol diete, while the remainder with control diet. Systolic blood pressure was measured weekly until 16 weeks after birth, and then biweekly until 40 weeks after birth. Transmission and scanning electron microscopy were used to evaluate ultrastrucural changes of the aorta. RESULTS: 1) The blood pressure of SHR rose stedily and progressively from the 5 weeks after birth and reached nearly 190mmHG at the 16 weeks after birth. 2) In SHR, the subendothelial component contained finely granular substances, abundant fibrillar collagen and elastin. Infiltration of the mononuclear blood leukocytes into the intima was frequently seen. 3) Endothelium from cholestrol-fed SHR did exhibit numerous pinocytotic vesicles and contained many cytoplasmic filaments. There were a number of large mononuclear lipid-filled cells in the intimal lesions. Blistering of the endothelial plasma membrane was also observed in high cholesterol diet-fed SHR. Later on, adhesion of platelets, febrin, and white blood cells as well as damage of intima shown as multiple small holes were more marked. 4) There was no significant difference in systoloic blood pressure between high cholesterol diet-fed and control diet-fed SHR. CONCLUSION: In the aorta of SHR, the most prominent change was an expansion of the subendothelial space and infiltration of the mononuclear leukocytes into the intima. The present study showed that the SHR was indeed a reliable model for the essential hypertension. In some SHR, high cholesterol diet could induce more pronounced vascular lesions, which were enhanced by hypertension.