Effect of lysophosphatidylcholine on whole cell K+ current in rabbit coronary smooth muscle cells

BACKGROUND: Impairment of relaxing response and augmentation of contractile response to vasoactive substances have been reported in atherosclerotic arteries. These alterations in vascular reactivity are considered as an underlying mechanism for the development of acute vasospasm in atherosclerotic coronary artery. Recently, it has been reported that lysophophatidylcholine (LPC), an oxidative metabolite of low density lipoprotein causes this functional abnormality. However, the precise mechanism of LPC induced change of vascular reactivity is still uncertain. METHOD: In this study, to elucidate the underlying mechanisms of abnormal vascular reactivity in atherosclerotic coronary artery, we examined the effect of LPC on whole cell K+current using patch clamping technique in rabbit coronary smooth muscle cells. RESULTS: Application of LPC(1microM) showed dual effect on whole cell outward current which depends on the magnitude of test potentials. At relatively high depolarizing test potentials (> 10 mV), LPC increased amplitude of outward current which was blocked by Gd3+ not by iberiotoxin (100 nM) and TEA (1 mM). Reversal potential of this Gd3+sensitive, LPC-induced current was -9.7 +/- 0.6 mV. At less depolarizing test potentials (< 10 mV), LPC decreased whole cell K+currents in a dose dependent manner (from 0.01 to 10 microM) in the range of -30 mV to +0 mV. Half maximal inhibition of K+current was 1.509 microM at 0 mV test potential (n =5). Depolarizing holding potential (0 mV) prevented this LPC-induced inhibition of K+current. Steady state activation and inactivation parameters of K+current were significantly shifted to the positive direction by application of LPC (p < 0.01, n =8). Pretreatment of staurosporine (100 nM), a blocker of protein kinase C partially blocked LPC-induced decrease of K+currents. CONCLUSION: LPC-induced inhibition of voltage dependent K+current may explain abnormal vascular reactivity in atherosclerotic coronary artery.

Risk Factor Analysis in Patients with Recurrent Cerebral Infarction by Transesophageal Echocardiography

OBJECTIVE: Among risk factors associated with cerebral infarction, cardiac factors are well known to be very important. However there were only few studies related to correlation between cardiac risk factors and stroke recurrence. So we tried to evaluate cardiac disease as a risk factor of recurrent cerebral infarction. METHOD: Subjects were 118 patients (62 male, 56 female) with cerebral infarction and were divided into first attack group as a control and recurred group. We evaluated the results of transesophageal echocardiographic study and other major risk factors and the results were compared in two groups using X2 test. RESULTS: Control group was 75 patients (39 male, 36 female), and recurred group was 43 patients (23 male, 20 female) and the mean ages were 62.8 years and 66.7 years, respectively. General transesophageal echocardiographic abnormalities were shown in 63 cases (84%) in control group and 40 cases (93%) in recurred group. Among the abnormal transesophageal echocardiographic findings, atherosclerosis of aorta was significantly higher in recurred group (49%) compared to control group (25%) (p<0.05), but there were no significant difference in aortic valve calcification, mitral calcification etc. Among the major risk factors of cerebral infarction, hypertension, diabetes, hyperlipidemia, and alcohol intake showed tendency of high incidence in the recurred group. Patients with abnormal EKG findings concurrent with abnormal transesophageal echocardiographic findings showed in 33 cases (44%) in control group, and 24 cases (56%) in recurred group, but there's no statistical significance. CONCLUSION: Our results do not support the hypothesis that TEE would be able to diagnose the cardiac risk factor for recurred cerebral infarction. However, the prevalence of atherosclerosis of aorta was significantly higher in recurrent group, so further studies would be needed.

Intraoperative Monitoring Using Somatosensory Evoked Potential during Spinal Deformity Surgery

OBJECTIVE: Intraoperative monitoring using somatosensory evoked potential (SEP) study has been used increasingly to monitor neurological function during scoliosis surgery and other high-risk spinal surgeries. However, there are few studies related to this intraoperative monitoring, particularly in severe spinal deformity surgery, in Korea. So we evaluated the clinical efficacy of intraoperative SEP monitoring and considered the risk factors related to spinal surgery. METHOD: We performed a posterior tibial nerve somatosensory evoked potential study for intraoperative monitoring during surgical procedures in 101 patients (male 46, female 55). RESULTS: Neurologic damage occurred in 16 patients (10 congenital scoliosis cases, 5 tuberculous kyphosis cases, and 1 degenerative spondylosis case) after surgical procedures. Delayed postoperative neurologic damage occurred in 4 patients (2 mild damage cases, 2 severe damage cases) among 85 cases which showed normal responses during surgical procedures. Sensitivity of this study was 75%, and specificity was 95.3%. CONCLUSION: Somatosensory evoked potential study for intraoperaive monitoring is a sensitive and very useful method to detect iatrogenic lesions during spinal deformity surgery with satisfactory specificity. However, to improve the sensitivity and specificity of the intraoperative monitoring, combination of motor evoked potentials is recommended.

Hand Rehabilitation of a Patient with Replantation of Forearm after Complete Amputation: A case report

Hand rehabilitation is essential to restore the maximal functional capacity of a patient after the injuries of hand or upper extremity, such as a fracture, tendon tear, crushing, or amputation. To achieve the purpose, hand rehabilitation should begin shortly after the completion of surgery. Especially after the replantation, functional recovery can be achieved by a careful inpatient evaluation providing a proper treatment, detecting problems, and updating treatment programs, and arranging discharge and follow-up cares by a hand rehabilitation team. We report our experience of a successful hand rehabilitation of patient with a replantation surgery after the complete right forearm amputation. A comprehensive approach and systematized treatment programs are important for a hand rehabilitation.