Effects of acute cerebral ischemia on cerebral perfusion: quantitative evaluation by contrast-enhanced ultrasound in dogs / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the changes of cerebral blood flow (CBF) with real-time contrast-enhanced ultrasound (CEU) in a canine model of acute cerebral ischemia.</p><p><b>METHODS</b>Cerebral perfusion was assessed in 6 dogs subjected to craniotomy with CEU at the time of 0, 30, 60, 90 and 120 min after occlusion of the left common carotid artery (LCCA). The microvascular volume (A) and blood flow velocity (beta) in the brain were measured from the time-versus-acoustic intensity plots, and the value of Axbeta were calculated. 99mTc-ECD brain single photon emission computed tomography (SPECT) was performed on the day before the experiment and at 120 min after LCCA occlusion. The radioactive counts on both sides of the cerebral cortex were calculated.</p><p><b>RESULTS</b>A significant correlation was found between Axbeta from CEU and volume of the blood flow of the CCA from Doppler flowmetry. A, beta and Axbeta values varied significantly between the different time points (P>0.001). The ipsilateral hemisphere showed a low-perfusion state while the contralateral hemisphere showed a high-perfusion state immediately after the occlusion.</p><p><b>CONCLUSIONS</b>The changes of beta is the main regulation mechanism during acute cerebral ischemia in dogs.</p>

Effect of obstructive sleep apnea syndrome on blood lipid and blood glucose in elderly hypertensive patients / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of obstructive sleep apnea syndrome (OSAS) on blood lipid and blood glucose in elderly hypertensive patients.</p><p><b>METHOD</b>a One hundred and seven elderly hypertensive patients received examinations by polysomnography and according to the apnea-hypopnea index (AHI), the patients were divided into four groups, namely uncomplicated hypertension group (n=23) and 3 hypertension groups with mild (n=31), moderate (n=29) and severe (n=24) OSAS. The fasting and 2-hour postprandial plasma glucose, glycosylated hemoglobin (HbA1c), total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), Apo-A, and Apo-B of these patients were measured.</p><p><b>RESULTS</b>aCompared with the non-OSAS patients, all the OSAS patients showed increased fasting and 2-hour postprandial plasma glucose, HbA1c, TC, TG, LDL and TC/HDL, and the increments were statistically significant in severe OSAS patients (P<0.05). The level of HDL was lowered in the OSAS groups, showing significant difference between severe OSAS group and the non-OSAS group (P<0.05). Apo-A level was lowered and Apo-B increased in the OSAS groups, but the differences were not statistically significant (P>0.05).</p><p><b>CONCLUSIONS</b>OSAS may produce harmful affect on the blood glucose and blood lipids in elderly hypertensive patients.</p>

Relationship between chronic congestive heart failure and sleep-disordered breathing in elderly patients / 南方医科大学学报

<p><b>OBJECTIVE</b>To determine the prevalence of sleep disordered breathing (SDB) in elderly patients with chronic congestive heart failure (CHF) and explore the relations between SDB and left ventricular function.</p><p><b>METHODS</b>By means of polysomnography, 56 elderly patients with CHF were divided into non-SDB, mild SDB, moderate SDB, and severe SDB groups, and the left ventricular ejection fraction (LVEF) was measure by (99)Tc equilibrium radionuclide angiography.</p><p><b>RESULTS</b>In the 56 elderly patients with CHF, 38 (67.9%) had SDB, including 12 (21.4%) mild SDB, 14 (25.0%) moderate SDB, and 12 (21.4%) severe SDB patients. Thirty (53.6%) of the 56 patients with CHF had obstructive sleep apnea (OSA), 4 (7.1%) had central sleep apnea and 22 (39.2%) had mixed sleep apnea. The moderate and severe SDB groups had lower minimum arterial oxyhemoglobin saturation during sleep than the non-SDB groups, and the apnea-hyponea index was closely related to LVEF (r=-0.74, P<0.01).</p><p><b>CONCLUSION</b>The prevalence of SDB, predominantly OSA, is high in elderly patients with CHF. Moderate and severe SDB might affect the left ventricular function in these patients, who require polysomnography monitoring.</p>