BACKGROUND: Cyclic flow variations(CFVs) is defined as morphological evidence of wide flow velocity variations in the Doppler signals due rapid spontaneous changes showing cyclic reduction and abrupt reperfusion of blood flow velocity seen in the critically stenotic arteries. Since first development of the CFVs model using dog by Folts and Uchida, it has been widely used as exellent experiemental model for study of the Acute ischemic heart disease syndrome including unstable angina. Nowadays it has been well documented that these CFVs are closely associated with temporal platelet aggregation and followed thrombus formation at the stenotic arterial lesion with endothelial or medial injury and subsequent release of various chemical mediators, eg. thromboxan A2 and serotonin. Also the CFVs can be seen in some patients of coronary artery stenosis during underwent PTCA, femoral artery stenosis and carotid or cerebral artery stenosis as well as in animal models. Moreover, CFVs has been thought to be the natural preconditioning in the unstable angina. METHODS: We tried to make the CFVs model using left anterior descending coronary artery (LAD) in 6 dogs. Pericardial cradle was made through 5th intercostal thoracotomy. The LAD was isolated carefully and critically stenosed by plastic constrictor and Doppler velocimeter probe was placed under the constrictor. After then intimal and medial layer of the LAD was damaged by a forcep. After appearing of CFVs, we observed and recorded for an hour. Myeloperoxide(MPO) activity in the ischemic and non-ischemic area of the myocardium were studied and compared after sacrifice. RESULTS: CFVs was found in all 6 dogs within an hour. The mean frequency of the CFVs was 9.8+/-4.45 times/hour. The mean coronary blood flow was 5.7+/-2.7 ml/min. And MPO activity was 1.47+/-0.5 units/g tissue in the ischemic myocardium and 0.49+/-0.27 units/g tissue in the non-ischemic area with statistical significance(p<0.005). CONCLUSIONS: CFVs model using various animal models and arterial sites can widely provide usefulness to document pathophysiology and pharmacologic mechanism in human acute ischemic heart disease syndromes.
Angina, Unstable ; Animals ; Arteries ; Blood Flow Velocity ; Cerebral Arteries ; Constriction, Pathologic ; Coronary Stenosis ; Coronary Vessels* ; Dogs ; Femoral Artery ; Humans ; Models, Animal ; Models, Theoretical* ; Myocardial Ischemia* ; Myocardium ; Plastics ; Platelet Aggregation ; Reperfusion ; Serotonin ; Surgical Instruments ; Thoracotomy ; Thrombosis

No abstract available.
Ambulatory Care Facilities* ; Humans ; Outpatients*

No abstract available.

No abstract available.

BACKGROUND: Gastroesophageal reflux is common in infants. The incidence of reflux in preterm infant has been reported to be higher than in fullterm infant. We perform this study to evaiuate the gastroesophageal reflux in preterm infant and fullterm infant. METHOD: A continuous 24 hour esophageal pH monitoring was performed in 28 asymptomatic infant(16 preterm infants and 12 fullterm infants). Four parameters(reflux index, number of reflux episodes in 24 hours, number of reflux episodesp 5 minutes in 24 hours, and duration of the longest reflux episode) were analyzed by gestation and birth weight. RESULT: All four parameters were not different in the low birth weight infant group(birth weight<2,500gm) compaired with infant of birth weight> or =2,500gm. In preterm infant group, mean reflux index was 3.08+/-6.84%; number of reflux episodes in 24 hours was 85.94+/-145.99; number of reflux episodes longer than 5 minutes was 0.38+/-0.72; and duration of the longest reflux episode was 3.69+/-4.88 minutes. In fullterm infant group, mean reflux index was 9.42+/-8.98%; number of reflux episodes in 24 hours was 190.58+/-158.27; number of reflux episodes longer than 5 minutes was 5.17+/-5.97; and duration of the longest reflux episode 16.58+/-15.41 minutes. Significant differences in reflux index, number of reflux episode longer than 5 minutes, and duration of the longest reflux episode were found between the preterm infant and fullterm infant. The number of reflux episodes in 24 hours was not different between preterm and fullterm infants. CONCLUSION: In continuous 24 hour esophageal pH monitoring, gastroesophageal reflux was more common in fullterm infant than preterm infant.
Birth Weight ; Esophageal pH Monitoring ; Gastroesophageal Reflux* ; Humans ; Hydrogen-Ion Concentration* ; Incidence ; Infant ; Infant, Low Birth Weight ; Infant, Newborn ; Infant, Premature* ; Parturition ; Pregnancy

No abstract available.
Hyperparathyroidism*

No abstract available.

No abstract available.
Gene Expression*

No abstract available.
Child* ; Drug Therapy* ; Humans

No abstract available.
Child* ; Drug Therapy* ; Humans