Morphological Adaptive Responses of Intercalated Cell of Renal Collecting Duct to Chronic Changes of Potassium Diet / 대한신장학회잡지

Potassium(K+) balance is achieved by the control of urinary K+ excretion and by the control of K+ absorption from the digestive tract. It has been established that chronic potassium depletion is associated with a remarkable hypertrophy of the outer medullary collecting duct of the kidney. But, there are no morphological studies regarding the intercalated cells during the chronic changes of potassium diet. Electron microscopy was performed to observe the morphological alterations of the intercalated cell of the entire collecting duct in response to chronic changes of potassium diet in rat kidney. By electron microscopy, the characteristic features of normal type A intercalated cell of the cortical collecting duct included numerous micro-projections of the apical plasma membrane, complicated basal infolding, apical cytoplasmic tubulovesicles, evenly distributed mitochondia, and centrally located nucleus. In potasium-depleted type A intercalated cell, microprojections of the apical plasma membrane were increased in length and number, basal infoldings were uncomplicated, tubulovesicles were almostly disappeared, and mitochondria were increased in number. Type A intercalated cell of potassium-loading after restriction was found to be almost normal except longer microprojections and increased mitochondria. The characteristic features of normal intercalated cell of the outer medullarycollecting duct(OMCD) included relatively short micro-projections of the apical plasma membrane, uncomplicated basal infoldings, apical cytoplasmic tubulovesicles, and apically distributed mitochondia. In comparison with normal, potassium-depleted intercalated cell of OMCD was hypertrophy, microprojections of the apical plasma membrane were increased in length and number, basal infoldings were complicated, tubulovesicles were almost disappeared, mitochondria were increased in number, and several lysosomes were appeared. Intercalated cell of OMCD of potassium-loading after restriction was found to be almost normal except increased cell size, longer microprojections, and increased mitochondria and lysosomes compared to control. The characteristic features of normal intercalated cell of the inner medullary collecting duct (IMCD) included very short and scant microprojections of the apical plasma membrane, uncomplicated basal infoldings,apica cytoplasmic tubulovesicles, evenly distributed mitochondia, and some lysosomes. In potasium-depleted intercalated cell of IMCD, cell size was prominently increased, microprojections of the apical plasma membrane were increased in length and number, basal infoldings were complicated, tubulovesicles were almostly disappeared, and mitochondria were increased in number. Intercalated cell of IMCD of potassium-loading after restriction was found to be almost normal except increased cell size and increased microprojections in number and length compared to control. These results suggest that intercalated cells adapt through morphological changes to preserve potassium balance during chronic changes of potassium diet.

Effects of Nicardipine and Sodium Nitroprusside on Functional Recovery of Stunned Myocardium in Dogs / 대한마취과학회지

BACKGROUND: Cytosolic Ca2+ overload and oxygen derived free radicals may contribute to stunned myocardium. The pnt study was aimed to investigate the effects of nicardipine and sodium nitroprusside (SNP) on the functional recovery of postischemic reperfused myocardium. METHODS: Fifty-seven halothane-anesthetized dogs were subjected to 15 minutes of 1eft anterior descending coronary artery (LAD) occlusion and 3 hours of reperfusion. They were randomly assigned to receive either intracoronary nicardipine (n=11) or SNP (n=10) alone or both (nicardipine plus SNP, n=10). Eleven dogs that received saline i.c. served as the controL Regional myocardial contractility was evaluated by systolic shortening (%SS), the preload recruitable stroke work slope (Mw), and intramyocardial pressure (IMPs). Diastolic function was assessed by time constant of myocardial relaxation (IMP-tau) and postsystolic shortening (%PSS), LAD blood flow was measured by a Doppler flowmeter as well. RESULTS: LAD occlusion produced a significant reduction in systolic as well as diasto1ic functions to similar degrees in all groups. However, %SS was significantly higher in the nicardipine, SNP and nicardipine-SNP groups (67%, 56%, and 68% of baseline values, respectively) than in the controls (20%) at 3 hours of reperfusion. Furthermore, Mw recovered to the baseline with the onset of reperfusian in the three experimental groups. IMP-tau was restored to the baseline during early nperfusion in the SNP-treated groups but was significantly prolonged in the control and nicardipine poups throughout the seperfusion. LAD blood flow during reperfusion was higher in the SNP-treated groups in comparison to the control group. CONCLUSIONS: Treatment with either nicardipine or SNP enhances the recovery of mgional contractile function in the canine model of myocardial stunning. SNP not nicardipine is also beneficial in attenuation of early diastolic dysfunction. Nicardipine combined with SNP improved systolic as well as early diastolic functions more significantly when compared to either nicardipine or SNP alane.

Changes in Arterial Blood Gases during Laparoscopic Cholecystectomy under the General Anesthesia / 대한마취과학회지

Changes in arterial blood gases and arterial pressure during laparoscopic cholecystectomy under the general anesthesia (enflurane in N2O/O2 50%) were investigated in 30 patients, who were divided into two groups according to control of minute ventilation. During surgery, minute ventilation was set 100 ml/kg in group I and 150 ml/kg in group II, and intraabdominal pressure was maintained at 15mmHg by CO2 insufflation, in both groups. Variables were measured before CO2 gas insufflation, 15 and 30 minutes after insufflation, just after exsufflation, 15 and 30 minutes after exsufflation and in recovery room. 1. PaCO2 was increased significantly during CO2 gas insufflation and just after exsufflation in both group, and degree of increase (PaCO2) was significantly greater in group I compared to group II. 2. Changes of PaO2 were not statistically significant in comparison to control value and between two groups during CO2 gas insufflation and exsufflation. 3. Blood pH in both groups were lowered significantly compared to control value during CO2 gas insufflation and exsufflation, and group II (increased minute ventilation group), represents lower risk of acidosis compared to group I. 4. Mean arterial pressure and airway pressure were significantly increased compared to control value during CO2 gas insufflation, but there was no significant difference between two groups. These results suggest that minute ventilation during laparoscopic cholecystectomy should be increased up to maintaining normal PaCO2 for prevention of hemodynamic and blood gas changes due to CO2 retention.