Inhibition of voltage-dependent K⁺ current in rabbit coronary arterial smooth muscle cells by the class Ic antiarrhythmic drug propafenone

In this study, we demonstrated the inhibitory effect of the Class Ic antiarrhythmic agent propafenone on voltage-dependent K⁺ (Kv) channels using freshly isolated coronary artery smooth muscle cells from rabbits. The Kv current amplitude was progressively inhibited by propafenone in a dose-dependent manner, with an apparent IC₅₀ value of 5.04±1.05 µM and a Hill coefficient of 0.78±0.06. The application of propafenone had no significant effect on the steady-state activation and inactivation curves, indicating that propafenone did not affect the voltage-sensitivity of Kv channels. The application of train pulses at frequencies of 1 or 2 Hz progressively increased the propafenone-induced inhibition of the Kv current. Furthermore, the inactivation recovery time constant was increased after the application of propafenone, suggesting that the inhibitory action of propafenone on Kv current is partially use-dependent. Pretreatment with Kv1.5, Kv2.1 or Kv7 inhibitor did not change the inhibitory effect of propafenone on the Kv current. Together, these results suggest that propafenone inhibits the vascular Kv channels in a dose- and use-dependent manner, regardless of Na⁺ channel inhibition.

Nortriptyline, a tricyclic antidepressant, inhibits voltage-dependent K+ channels in coronary arterial smooth muscle cells

We demonstrated the effect of nortriptyline, a tricyclic antidepressant drug and serotonin reuptake inhibitor, on voltage-dependent K⁺ (Kv) channels in freshly isolated rabbit coronary arterial smooth muscle cells using a whole-cell patch clamp technique. Nortriptyline inhibited Kv currents in a concentration-dependent manner, with an apparent IC₅₀ value of 2.86±0.52 µM and a Hill coefficient of 0.77±0.1. Although application of nortriptyline did not change the activation curve, nortriptyline shifted the inactivation current toward a more negative potential. Application of train pulses (1 or 2 Hz) did not change the nortriptyline-induced Kv channel inhibition, suggesting that the effects of nortiprtyline were not use-dependent. Preincubation with the Kv1.5 and Kv2.1/2.2 inhibitors, DPO-1 and guangxitoxin did not affect nortriptyline inhibition of Kv channels. From these results, we concluded that nortriptyline inhibited Kv channels in a concentration-dependent and state-independent manner independently of serotonin reuptake.

Escitalopram, a selective serotonin reuptake inhibitor, inhibits voltage-dependent K⁻ channels in coronary arterial smooth muscle cells

We investigated the inhibitory effect of escitalopram, a selective serotonin reuptake inhibitor (SSRI), on voltage-dependent K⁺ (Kv) channels in freshly separated from rabbit coronary arterial smooth muscle cells. The application of escitalopram rapidly inhibited vascular Kv channels. Kv currents were progressively inhibited by an increase in the concentrations of escitalopram, suggesting that escitalopram inhibited vascular Kv currents in a concentration-dependent manner. The IC₅₀ value and Hill coefficient for escitalopram-induced inhibition of Kv channels were 9.54±1.33 µM and 0.75±0.10, respectively. Addition of escitalopram did not alter the steady-state activation and inactivation curves, suggesting that the voltage sensors of the channels were not affected. Pretreatment with inhibitors of Kv1.5 and/or Kv2.1 did not affect the inhibitory action of escitalopram on vascular Kv channels. From these results, we concluded that escitalopram decreased the vascular Kv current in a concentration-dependent manner, independent of serotonin reuptake inhibition.

The Communication Styles and Nursing Service Satisfaction of Clinical Research Nurses Perceived by Clinical Subjects / 한국간호교육학회지

PURPOSE: This study aimed to examine the communication styles and nursing service satisfaction of clinical research nurses perceived by clinical subjects. METHODS: The data were collected with self-administrated questionnaires after receiving consents from 200 clinical trial subjects. The data were analysed with descriptive statistics, t-test, ANOVA, Pearson's correlation coefficients and stepwise multiple regression analysis using SPSS 21.0 statistic program. RESULTS: Clinical subjects perceived that clinical research nurses used the informative, affective, and non-authoritative communication styles. The study identified factors influencing the nursing service satisfaction, and they were the informative communication styles (β=.34, p<.001) and affective communication styles (β=.35, p<.001, R2=37%) by multiple linear regression. CONCLUSION: If educational programs on communication are developed to help clinical research nurses use the informative and affective communication styles according to the characteristics of subjects and applied to the field of practice, they will be able to increase the nursing service satisfaction and contribute to the higher quality of clinical trials.

Validation of the Oxford Classification of IgA Nephropathy: A Single-Center Study in Korean Adults

BACKGROUND/AIMS: The recently published Oxford classification of IgA nephropathy (IgAN) proposed a split system for histological grading, based on prognostic pathological features. This new classification system must be validated in a variety of cohorts. We investigated whether these pathological features were applicable to an adult Korean population. METHODS: In total, 69 adult Korean patients with IgAN were analyzed using the Oxford classification system at Soonchunhyang University Hospital, Seoul, Korea. All cases were categorized according to Lee's classification. Renal biopsies from all patients were scored by a pathologist who was blinded to the clinical data for pathological variables. Inclusion criteria were age greater than 18 years and at least 36 months of follow-up. We excluded cases with secondary IgAN, diabetic nephropathy combined other glomerulopathies, less than 36 months of follow-up, and those that progressed rapidly. RESULTS: The median age of the patients was 34 years (range, 27 to 45). Mean arterial blood pressure was 97 +/- 10 mmHg at the time of biopsy. The median follow-up period was 85 months (range, 60 to 114). Kaplan-Meier analysis showed significant prognostic predictions for M, E, and T lesions. A Cox proportional hazard regression analysis also revealed prognostic predictions for E and T lesions. CONCLUSIONS: Using the Oxford classification in IgAN, E, and T lesions predicted renal outcome in Korean adults after taking clinical variables into account.

Bile-Duct Stone Removal under Direct Transnasal Cholangioscopy Using an Ultraslim Upper Endoscope

The transnasal endoscopic examination using an ultraslim upper endoscope may be more comfortable and less stressful than the peroral approach. Transnasal endoscopic retrograde cholangiopancreatography (ERCP), endoscopic nasobiliary drainage, and direct peroral cholangioscopy using an ultraslim upper endoscope have recently been reported. An 82-year-old woman with a previous history of endoscopic sphincterotomy and stone removal was admitted with acute cholangitis. Instead of conventional ERCP, we performed direct transnasal cholangioscopy (TNC) using an ultraslim upper endoscope for biliary decompression and stone removal because of her unstable vital signs. Direct TNC using an ultraslim upper endoscope may be useful in selected patients with biliary disease.