PURPOSE: Epistemological beliefs (EBs) are fundamental assumptions about the nature of knowledge and learning. Self-regulation (SR) is the ability and willingness to effectively use and monitor cognitive strategies. Problem-based learning (PBL) emphasizes meaningful learning through solving ill-structured problems. PBL, as a constructivist learning environment, affects students' epistemological beliefs (EBs) and self-regulation learning (SRL). The purpose of this study was to investigate the change in EBs and SRL between pre- and post-PBL. METHODS: The subjects were 123 third-year medical students who attended Chonnam National University Medical School (CNUMS), Korea. Participants had to fill out a questionnaire concerning epistemological beliefs and self-regulated learning before and after PBL. RESULTS: Students' EBs about rigid learning was positively changed; however, certainty of knowledge and speed of knowledge acquisition were negatively changed after PBL. Students' SRL related to self-efficacy and self-regulation was significantly improved in PBL. There was no significant change with regard to internal value, cognitive strategy, and anxiety. CONCLUSION: EBs on certainty of knowledge and speed of knowledge acquisition were negatively changed after PBL. This result may be due to other leaning environments besides PBL i.e., the lecture-based objective learning environment of medical school. It is suggested that partial PBL cannot fully change students' EBs to higher levels. Students' SR about self-efficacy and self-regulation was significantly improved in PBL. The characteristics of PBL: small-group discussion and co-operative team activity, as well as students-centered learning environments, facilitate self-efficacy, and self-regulation.
Anxiety ; Humans ; Korea ; Learning ; Organothiophosphorus Compounds ; Problem-Based Learning ; Schools, Medical ; Students, Medical ; Surveys and Questionnaires

PURPOSE: The Professional Graduate Medical School (PGMS) was established in 2003 in South Korea to train doctors that had better humanities and various educational backgrounds. By comparing the learning styles between students of the Medical College (MC) and PGMS, we investigated the characteristics of these students. METHODS: The Kolb Learning Style Inventory (LSI) is used to determine learning preferences. It is composed of 12 statements on concrete experience, reflective observation, abstract conceptualization, and active experimentation. Six hundred nine students from all years of the 2 medical schools completed the Kolb LSI between June 1st and June 30th, 2008 (response rate: 91.4%). RESULTS: MC students preferred Kolb's 'assimilator (56.3%)' and 'diverger (25.6%)', and PGMS students preferred Kolb's 'assimilator (61.2%)' and 'converger (19.3%)'. PGMS students showed a higher preference for abstract conceptualization compared with MC students (adjusted Odds Ratio=2.191; 95% Confidence Interval=1.115~4.306). CONCLUSION: This study showed that the learning styles of PGMS and MC students differed. We can use this result not only in developing curricula and teaching strategies, but also in providing support to students.
Curriculum ; Humanities ; Humans ; Learning ; Republic of Korea ; Schools, Medical ; Students, Medical

PURPOSE: For medical students to have a meaningful learning experience, the curriculum must integrate what students are learning in class with the skills and knowledge required in the clinicalsetting. To satisfy these needs, an integrated curriculum (IC) has been operating at Chonnam National University Medical School since 1999. The purpose of this study was to evaluate the changes in IC students during two implementation periods, the first in 2001 and the second in 2004. This study focused on the student viewpointin order to create an authentic IC program. METHODS: Questionnaires were used to evaluate the differences in the student perception of IC. The content of the questionnaire dealt with the appropriateness of time management, coherence of the content, teachinglearning method, and IC evaluation. RESULTS: There were positive responses from the second implementation period than from the first, for almost all sub-items. However, the results showed that IC has to be reinforced by instructors teaching a coherentcontent, by using a variety of teaching-learning methods, by having the students participate actively, and by offering holistic and integrated assessments. CONCLUSION: The following three steps are recommended for the improvement of IC: facilitate an IC committee, develop teaching-learning methods, and guide student participation.
Curriculum* ; Humans ; Jeollanam-do ; Learning ; Schools, Medical ; Students, Medical ; Time Management ; Surveys and Questionnaires

Proliferating trichilemmal cyst(proliferating trchilemmal tumor, PTC) most commonly occurs in the scalp and is generally benign. Malignant transformation of PTC is rare, and the appearance of a spindle cell(sarcomatoid) carcinoma is extremely rare. The authors experienced a case of malignant proliferating trchilemmal tumor with spindle cell carcinoma on the scalp in a 41-year-old male. The tumor was widely resected and covered with split thickness skin graft after Terudermis(R) graft. Imaging studies and fine needle aspiration cytology showed no regional lymph node involvement or distant matastasis.
Adult ; Biopsy, Fine-Needle ; Humans ; Lymph Nodes ; Male ; Scalp ; Skin ; Transplants

BACKGROUND AND OBJECTIVES: It has been reported that intracoronary radiation therapy (ICRT) using a Ho-166 coated balloon inhibits restenosis of porcine coronary arteries. However, the consequences of ICRT on coronary artery endothelial function are unknown. The aim of this study is to investigate the effects of ICRT using a Ho-166 balloon on coronary artery endothelial function and vasomotor reactivity. MATERIALS AND METHODS: Female pigs (25-35 kg) were orally premedicated daily with aspirin (100 mg) and ticlopidine (250 mg) for the duration of the study. Under sterile conditions with local anesthesia of the skin provided by 2% lidocaine, an arteriotomy of the left carotid artery was performed, an 8 Fr sheath was inserted, and intraarterial heparin sodium (10,000 IU) was injected. Under fluoroscopic guidance, the coronary artery main branch was selected through an 8 Fr guiding catheter for coronary artery overdilation injury (balloon to artery ratio, 1.3:1) and ICRT. A Ho-166 coated balloon prepared to deliver 20 Gy at a depth of 2 mm from the balloon surface was used for ICRT. The coronary artery main branch in each pig was randomly assigned to either balloon injury (Group I) or balloon injury plus ICRT (Group II). Coronary artery segments were taken from the animals at 0 week (n=8), 4 weeks (n=6) and 8 weeks (n=8) after the intervention. Data in each group denote the relative ratio compared to non-injured coronary artery and are expressed as mean +/- standard error of mean. RESULTS: The degree of KCl-induced contractile response (g) was not different between the two groups at 0 and 4 weeks, but was significantly decreased in group II compared to group I at 8 weeks (I:1.04+/-0.06, II:0.79+/-0.07, p=0.014). In rings precontracted with prostaglandin F 2alpha (PGF 2alpha), the degree of NO-dependent relaxation (%) induced with substance P was significantly decreased in group II compared to group I at 0 week (I:0.93+/-0.33, II:0.47+/-0.31, p=0.03), but the difference between the two groups was not significant at 4 and 8 weeks. In rings precontracted with PGF 2alpha and LAME in the presence of indomethacin, the degree of EDHF-induced relaxation (%) using substance P was not different between the two groups at 0, 4 and 8 weeks; nor was the degree of sodium nitroprusside-induced endothelium independent relaxation (%) in depolarized conditions with PGF 2alpha. CONCLUSION: Endothelial function of the porcine coronary artery is only transiently impaired after ICRT using a Ho-166 coated balloon. Therefore this therapy can be used as an effective method to prevent restenosis after percutaneous coronary intervention.
Anesthesia, Local ; Angioplasty ; Animals ; Arteries ; Aspirin ; Carotid Arteries ; Catheters ; Coronary Restenosis ; Coronary Vessels ; Endothelium ; Female ; Heparin ; Humans ; Indomethacin ; Lidocaine ; Percutaneous Coronary Intervention ; Prostaglandins F ; Relaxation ; Skin ; Sodium ; Substance P ; Swine ; Ticlopidine

In clinical therapy, the current goal of dental implants is to enhance quantity and quality of osseointegration. Surface roughness and oxide structure are considered to influence the behavior of adherent cells. The purpose of this study is to evaluate the effect of different surface treatment on cellular response. The attachment and proliferation of osteoblast-like cell on sandblasted, sandblasted and etched, thermal oxidated surfaces have been compared. Sandblasting was done with Al2O3 particles(grain size of 50micrometer), etching was processed with NH4OH : H2O2 : H2O(1:1:5) at 90degrees C for 1 minute. Thermal oxidation was followed sandblasting and etching at 400degrees C, 600degrees C, 800degrees C for 2 hours. Measurement of surface roughness after the different treatment did not show any differences of Ra value between terated surfaces. Cell attachment and proliferation were increased during experiment period, but no difference was observed. SEM evaluation revealed a similar pattern of osteoblastlike cells, well attached with dendritic extension and producing numerous matrix vesicles on cell surface. The results of this study showed that oxide layer alteration by thermal oxidation did not affect the attachment and proliferation of osteoblast-like cells. This suggests the possibility that the cellular responses are further influenced by surface roughness than titaniun oxide structure. This study was supported by a grant(HMP-98-G-2-035-B) of the HAN(highly advanced National) Projected, Ministry of Health & Welfare, R.O.K
Dental Implants ; Osseointegration ; Osteoblasts

BACKGROUND: To evaluate the role of free fatty acids on the ischemic myocardium, influences of various free fatty acids upon transmembrane action potential and ATP-sensitive K+(KATP) channel activity were examined in the ventricular myocardium and single cardiac myocytes. METHODS: KATP channel activities were measured in the enzymatically (collagenase) isolated single rat ventricular cardiac myocytes by the method of the excised inside-out and the cell-attached patch clamp, and transmembrane action potentials were recorded using the conventional 3M-KCl microelectode techniques in the rat ventricular myocardium. RESULTS: Free fatty acids [FFAs; arachidonic acid (AA), linoleic acid (LA) and lysophosphatidylcholine (LPC)] reduced the KATP channel activity in a dose-dependent manner in the inside-out patch, and 50%-inhibition concentrations (IC50) were 88 +/- 11.2, 49 +/- 12.5, and 188 +/- 17.4 M respectively. Both frequency of channel opening and the mean open-burst duration were markedly decreased, but the amplitude of single channel currents were not changed by the FFAs. AA (50 micrometer) and LPC (50 micrometer) did not affect the dinitrophenol (DNP, 50 micrometer)-induced KATP channel activity, whereas LA (50 micrometer) had a tendency to reduce the activity. The channel inhibition effects by 10 micrometer AA in the inside-out patch were significantly augmented by diclofenac (10 micrometer), but was not changed by nordihydroguaiaretic acid. FFAs never stimulated KATP channel activity, even in the inside-out patch where KATP channel activity reduced in the presence of internal ATP (100 micrometer). Time for 90% repolarization (APD90) significantly increased during superfusion of the FFAs, to 22 (50 micrometer AA), 24 (50 micrometer LA), and 18 (50 micrometer LPC) % from those of the contol at the time of 10 min superfusion, but the other action potential characteristics were not changed by the FFAs. AA (10 micrometer) attenuated cromakalim (10 micrometer)-induced APD90 shortening effects. CONCLUSION: It was inferred that FFAs inhibit the KATP channel activity directly by themselves and/or indirectly by their metabolites in the rat ventricular cardiomyocytes, and therefore, duration of action potential lengthens to be a burden over the ischemic myocardium accounting for the injury of myocardium at the late stage of ischemia.
Action Potentials* ; Adenosine Triphosphate ; Animals ; Arachidonic Acid ; Cromakalim ; Diclofenac ; Fatty Acids, Nonesterified* ; Ischemia ; Linoleic Acid ; Lysophosphatidylcholines ; Masoprocol ; Myocardium* ; Myocytes, Cardiac ; Potassium Channels* ; Potassium* ; Rats*

This study was designed to investigate effects of calcium antagonists on endothelial and neuronal dysfunction of right coronary artery (RCA) induced by ischemia- reperfusion in anesthetized, open-chest pigs. After reperfusion, pigs were sacrificed and the RCA was rapidly dissected for in vitro experiments. Experimental groups were divided into 4 groups: control (C-RCA), ischemia-reperfusion only (I-RCA), verapamil infusion (VI-RCA) and nifedipine infusion (NI-RCA) group, respectively. The ischemia did not affect hemodynamics, mean arterial pressure, heart rate, LVdP/dtmax, and decreased RCA flow. Arterial pressure and heart rate during ischemia-reperfusion were decreased in VI-RCA and NI-RCA, and RCA flow during reperfusion was increased in NI-RCA. 5-Hydroxytryptamine (5-HT) produced concentration-dependent contractions in C-RCA. The 5-HT-induced contractions were potentiated in I-RCA and VI-RCA, but not in NI-RCA. Endothelium-dependent relaxation by calcium ionophore A23187 was inhibited in I-RCA and VI-RCA, and recovered in NI-RCA. Cyclic GMP contents were decreased in I-RCA group alone. Electrical field stimulation in C-RCA produced transient and frequency-dependent contractions and at 50 Hz caused biphasic contractions. The transient contractions were not affected by pretreatment with phentolamine and atropine, but the biphasic contraction was altered by the pretreatment. Both contractions were inhibited in I-RCA, and were partially recovered in VI-RCA and NI-RCA. Ischemia-reperfusion of RCA in pigs causes endothelial and neuronal dysfunctions, and calcium antagonists partially prevent both.
Arterial Pressure ; Atropine ; Calcimycin ; Calcium Channel Blockers* ; Calcium Channels* ; Calcium* ; Coronary Vessels ; Cyclic GMP ; Heart Rate ; Hemodynamics ; Ischemia ; Neurons ; Nifedipine ; Phentolamine ; Relaxation ; Reperfusion ; Serotonin ; Swine ; Verapamil

A K+-channel blocker, 4-aminopyridine(4-AP) increases neurotransmitter release from motor nerve terminals and has been shown to restore neuromuscular transmission in the myasthenic syndrome. It has been reported that the intravenous injection of 4-AP in the myasthenic patients caused many central adverse effects including anxiety and restlessness, but did not affect the blood pressure. The aim of this study was to observe the effect of intracerebroventricularly administered 4-AP on the blood pressure and to elucidate the mechanism of the action in urethane-anesthetized rabbits. Intracerebroventricular(icv) 4-AP produced pressor effects in a dose-dependent fashion, but intravenous(iv) 4-AP of the same dose did not altered the blood pressure. Tetraethylammonium, a K+-channel blocker which differs from 4-AP structurally, had little effect on the blood pressure, but 3,4-diaminopyridine, another derivative of the aminopyridine, produced pressor effect similar to 4-AP. The pressor effect of icv 4-AP was not affected by the treatment with iv phenoxybenzamine and chlorisondamine, and in bilateral adrenalectomized rabbits. These results suggest that the 4-AP pressor effect is not related to the periphral sympathetic nerve nor adrenal gland. The pretreatment with icv phentolamine and prazosin did not altered the 4-AP pressor. However, the icv 4-AP pressor effect was significantly attenuated by the treatment with icv yohimbine, and significantly potentiated by the treatment with icv clonidine. The treatment with icv diltiazem markedly inhibited the icv 4-AP pressor effect. It is concluded that 4-AP-sensitive K+-channels in rabbit brain might play a role in the regulation of blood pressure and that the 4-AP pressor effect is closely related to the central alpha2-adrenoceptors and L-type calcium channels.
4-Aminopyridine* ; Adrenal Glands ; Anxiety ; Arterial Pressure* ; Blood Pressure ; Brain ; Calcium Channels, L-Type ; Chlorisondamine ; Clonidine ; Diltiazem ; Humans ; Injections, Intravenous ; Neurotransmitter Agents ; Phenoxybenzamine ; Phentolamine ; Prazosin ; Psychomotor Agitation ; Rabbits ; Tetraethylammonium ; Yohimbine

To elucidate the mechanism involved in the cerebral vascular spasm following subarachnoid hemorrhage (SAH), the effects of the cerebrospinal fluid (CSF) obtained from the SAH patients on the resting tension and its influence on the contractile responses to various vasoactive agents and to hypoxia were investigated in isolated porcine cerebral arteries. All the CSFs containing hemoglobin (Hb) produced contraction and some Hb-free CSFs also elicited contraction. When the Hb-free CSF was separated by microfilter, the filtrate of < 30,000 MW did not produce contraction, while the fraction above 30,000 MW elicited more marked contractile responses than the unfractionated CSF. The CSF contraction was significantly attenuated in the presence of indomethacin or nimodipine, whereas the contractions induced by KCl, prostaglandin F2alpha (PGF2alpha), or endothelin-1 (ET-1) were not affected by the CSF pretreatment. However, the contractile responses induced by 5-hydroxytryptamine (5-HT) and phenylephrine (PE) were markedly potentiated by the pretreatment. Hypoxia-induced vasoconstriction was significantly potentiated by the pretreatment with either unfractionated CSF or the CSF fraction of above 30,000 MW. These results suggest that unknown vasocontractile substance(s) exists in the Hb-free CSF and that the substance, with its MW above 30,000, is activated by hypoxia and acts synergistically with 5-HT and PE, and that extracellular calcium influx and cyclooxygenase are also involved in the cerebral vasoconstrictory effect of Hb-free CSF.
Anoxia ; Calcium ; Cerebral Arteries* ; Cerebrospinal Fluid* ; Dinoprost ; Endothelin-1 ; Humans* ; Indomethacin ; Nimodipine ; Phenylephrine ; Prostaglandin-Endoperoxide Synthases ; Serotonin ; Spasm ; Subarachnoid Hemorrhage ; Vasoconstriction