Isolation and Expression Profile of the Ca(2+)-Activated Chloride Channel-like Membrane Protein 6 Gene in Xenopus laevis / 한국실험동물학회지

To clone the first anion channel from Xenopus laevis (X. laevis), we isolated a calcium-activated chloride channel (CLCA)-like membrane protein 6 gene (CMP6) in X. laevis. As a first step in gene isolation, an expressed sequence tags database was screened to find the partial cDNA fragment. A putative partial cDNA sequence was obtained by comparison with rat CLCAs identified in our laboratory. First stranded cDNA was synthesized by reverse transcription polymerase-chain reaction (RT-PCR) using a specific primer designed for the target cDNA. Repeating the 5' and 3' rapid amplification of cDNA ends, full-length cDNA was constructed from the cDNA pool. The full-length CMP6 cDNA completed via 5'- and 3'-RACE was 2,940 bp long and had an open reading frame (ORF) of 940 amino acids. The predicted 940 polypeptides have four major transmembrane domains and showed about 50% identity with that of rat brain CLCAs in our previously published data. Semi-quantification analysis revealed that CMP6 was most abundantly expressed in small intestine, colon and liver. However, all tissues except small intestine, colon and liver had undetectable levels. This result became more credible after we did real-time PCR quantification for the target gene. In view of all CLCA studies focused on human or murine channels, this finding suggests a hypothetical protein as an ion channel, an X. laevis CLCA.

Does ST-segment depression combined with R wave amplitude change improve the test accuracy of the EKG during exercise testing? / 대한내과학회지

BACKGROUND: Exercise electrocardiogram is the most widely used non-invasive test in those patients suspected of having coronary artery disease. However, sensitivity and specificity of this test are not satisfactory, especially when the exercise induced ST-segment depression is used as a single criterion of myocardial ischemia. Although many investigators have tried to improve diagnostic accuracy with R-wave amplitude change in addition to ST-segment depression, controversy exists whether this new criteria improve the test accuracy for coronary artery disease or not. The purpose of this study is to determine the test accuracy of R-wave amplitude change induced by exercise combined with the conventional ST-segment criterion for myocardial ischemia. METHODS: We reviewed our records of patients who visited to Korea University Anam Hospital with chest pain from January, 1998 to July, 1999. We included 130 patients with chest pain who had a tredmill test followed by a coronary angiography within 2 months. Patients with change in ST-segment depression (delta STD)> or = 1.00 mm and delta STD> or = 1.00 mm with R wave amplitude decrease (-delta R)> or = 1.00 mm in the same lead in any of 12 leads and delta STD> or = 1.00 mm with R wave amplitude increase (+delta R)> or = 1.00 mm in the same lead in any of 12 leads were compared. According to the findings of coronary angiograms, patients were divided into 4 groups ; normal coronary artery group, mild coronary artery stenosis group (> or = 30% to or = 50% to or = 70%). RESULTS: Fifty three patients (40.7%) had normal coronary angiograms and 77 patients (59.3%) had coronary artery stenosis. There was no significant difference in gender and age. But, patients with coronary artery stenosis had more diabetes mellitus, hyperlipidemia, smoking, previous myocardial infarction history and angina during exercise testing than those without coronary artery stenosis. The sensitivity of exercise EKG is significantly decreased when combined with delta R (delta STD, 74.0%, delta STD with -delta R, 45.5%, delta STD with +delta R, 30.0%, p<0.01), but the The test accuracy is delta STD; 73.7%, delta STD with -delta R; 61.5%, delta STD with +delta R; 57.7%. CONCLUSION: When ST-segment depression is combined with R-wave amplitude change as a marker for myocardial ischemia, the specificity is increased, but the test accuracy of exercise EKG is not improved.

Activation Patterns Following Successful and Unsuccessful DC Cardioversion for Atrial Fibrillation

BACKGROUND AND OBJECTIVES: The mechanism by which atrial fibrillation (AF) electrically converts to sinus rhythm remains undefined. The purpose of this study was to assess in detail the electrograms recorded during cardioversion using direct current (DC) shock. SUBJECTS AND METHODS: In 23 patients with AF (chronic n=20, paroxysmal n=3, M:F=15:8, 50 - 70 years old), electrograms were recorded simultaneously from a 20-pole electrode catheters (Duo-deca, DAIG) in the right atrial free wall and the coronary sinus immediately after DC shock given transthoracically. The activation patterns following 45 trials consisting of 23 successful and 22 unsuccessful cardioversion were analyzed. RESULTS: Two distinct patterns following successful cardioversion were observed; either immediate resumption of normal sinus rhythm (n=5, 21%), or one or two activations immediately after shock preceded normal sinus rhythm (n=18, 79%). The energy levels of the two patterns were not significantly different (260 J, 250 J, respectively). Four patterns following unsuccessful cardioversion were noted; unchanged (n=10, 45%), converted to atrial flutter (n=4, 18%), production of three or four beats of more coordinated complexes and reverted to AF (n=5, 22%), and converted to sinus rhythm transiently and reinitiated AF by one or two atrial premature beats (n=3, 13%). The magnitude of the DC shock applied at these 4 different patterns was 196 J, 240 J, 264 J, and 340 J, respectively in which low energy levels made a simultaneous depolarization of the entire atria unlikely. CONCLUSION: Distinct activation patterns were identified following successful and unsuccessful cardioversion using DC shock for AF. These observations suggest that total depolarization of the entire atria is not a prerequisite for the conversion of AF into sinus rhythm.

The Effect of Inhaled Concentration of N2O (Nitrous Oxide) during Emergenceon Awakening Time after Propofol-N2O-O2 Anesthesia / 대한마취과학회지

BACKGROUND: N2O has a unique analgesic effect and reduces the amount of hypnotics for preventing surgical stimuli during maintenance of anesthesia. Also, it was reported that high concentrations of N2O affect level of consciousness. The aim of this study was to evaluate the effect of inhaled concentrations of N2O during emergence on awakening time after propofol-N2O-O2 anesthesia. METHODS: Sixty ASA class I or II patients scheduled for lower extremity surgery were randomly allocated to one of three groups according to inhaled concentration of N2O during emergence. Group 1: 0% N2O (n = 20), group 2: 33% N2O (n = 20) and group 3: 50% N2O (n = 20). Anesthesia was induced and maintained with propofol (Ct: 3.5 6 microgram/ml)-67% N2O-33% O2 and the target concentration of propofol was kept at 4 microgram/ml at least 30 min before the end of infusion of propofol using TCI. At the time of skin closure, we discontinued the propofol, maintained the allocated concentration of N2O and continuously checked vital signs, current/effect concentration of propofol, bispectral index (BIS), and elapsed time until eye opening to verbal contact (awakening time). RESULTS: Awakening time and bispectral index significantly increased as the inhaled concentration of N2O was higher. At awakening time, The predicted current/effect site concentrations of propofol significantly decreased as the inhaled concentrations of N2O were increased. CONCLUSIONS: Continuous inhalation of N2O after discontinuation of propofol infusion significantly delayed the awakening time after propofol-N2O-O2 anesthesia using TCI.

Two Cases of Catheter Ablation of Atrioventricular Reentrant Tachycardia by Right Septal Bypass Tract Mapped Using Multielectrode Basket Catheter

It has been known that right side bypass tract ablation is more difficult and has higher recurrence rate than that of left side bypass tract, and often associated with atrioventricular block in patients with septal bypass tract. Multielectrode basket catheter (MBC) allows simultaneous rapid acquisition of numerous electrical signals generated by a selected surface area or volume of myocardium. We experienced two cases of successful catheter ablation of atrioventricular reentrant tachycardia by right septal bypass tract which were mapped by MBC with greater ease.