Inhibitory effects of the atypical antipsychotic, clozapine, on voltage-dependent K+ channels in rabbit coronary arterial smooth muscle cells

To investigate the adverse effects of clozapine on cardiovascular ion channels, we examined the inhibitory effect of clozapine on voltage-dependent K+(Kv) channels in rabbit coronary arterial smooth muscle cells. Clozapine-induced inhibition of Kv channels occurred in a concentration-dependent manner with an halfinhibitory concentration value of 7.84 ± 4.86 µM and a Hill coefficient of 0.47 ± 0.06.Clozapine did not shift the steady-state activation or inactivation curves, suggesting that it inhibited Kv channels regardless of gating properties. Application of train pulses (1 and 2 Hz) progressively augmented the clozapine-induced inhibition of Kv channels in the presence of the drug. Furthermore, the recovery time constant from inactivation was increased in the presence of clozapine, suggesting that clozapineinduced inhibition of Kv channels is use (state)-dependent. Pretreatment of a Kv1.5 subtype inhibitor decreased the Kv current amplitudes, but additional application of clozapine did not further inhibit the Kv current. Pretreatment with Kv2.1 or Kv7 subtype inhibitors partially blocked the inhibitory effect of clozapine. Based on these results, we conclude that clozapine inhibits arterial Kv channels in a concentrationand use (state)-dependent manner. Kv1.5 is the major subtype involved in clozapineinduced inhibition of Kv channels, and Kv2.1 and Kv7 subtypes are partially involved.

The thickness of alveolar bone at the maxillary canine and premolar teeth in normal occlusion

PURPOSE: The main purpose of this study was to investigate bone thickness on the buccal and palatal aspects of the maxillary canine and premolars using cone-beam computed tomography (CBCT). The differences between left- and right-side measurements and between males and females were also analyzed. METHODS: The sample consisted of 20 subjects (9 males and 11 females; mean age, 21.9+/-3.0) selected from the normal occlusion sample data in the Department of Orthodontics, The Catholic University of Korea. The thickness of the buccal and palatal bone walls, perpendicular to the long axis of the root were evaluated at 3 mm and 5 mm apical to cemento-enamel junction (CEJ) and at root apex. RESULTS: At the canines and first premolars regions, mean buccal bone thickness of at 3 mm and 5 mm apical to CEJ were less than 2 mm. In contrast, at the second premolar region, mean buccal bone thickness at 3 mm and 5 mm apical from CEJ were greater than 2 mm. Frequency of thick bone wall (> or =2 mm) increased from the canine to the second premolar. CONCLUSIONS: This result should be considered before tooth extraction and planning of rehabilitation in the canine and premolar area of maxilla. Careful preoperative analysis with CBCT may be beneficial to assess local risk factors and to achieve high predictability of success in implant therapy.

Factors Influencing the Specialty Selection of Medical Students / 한국의학교육

PURPOSE: We wanted to further analyze the qualities that influence Korean medical students on their decision to choose each of the specialized areas of medicine. METHODS: We were able to obtain questionnaires from 394 students of Y University, School of Medicine. The students rated the various influential factors for specialty selection by using a five-point Likert scale. RESULTS: The factors found to influence the selection of popular specialties were gender, grades/scores, lifestyle attributes, and residency issues. Patient contact, lifestyle attributes, prospects, income prospects, and health care policies were significantly rated factors for choosing clinical-oriented specialties. For the selection of Medical specialties, gender, income, social responsibilities, income prospects, and malpractice insurance costs were the influential factors. Gender, 3rd year students, social responsibilities, prospects, income prospects, and society's views on medical profession affected the students' decisions to choose the major specialties. CONCLUSION: Based on the results of our study, we can conclude that gender and income prospects are some of the most significant factors affecting a student's selection of a specialty. These results suggest reform and improvement for a more stable health care policy and management strategies.