Ethyl-2, 5-dihydroxybenzoate displays dual activity by promoting osteoblast differentiation and inhibiting osteoclast differentiation.

The interplay between bone-forming osteoblasts and bone-resorbing osteoclasts is essential for balanced bone remodeling. In this study, we evaluate the ability of ethyl-2, 5-dihyrdoxybenzoate (E-2, 5-DHB) to affect both osteoblast and osteoclast differentiation for bone regeneration. Osteogenic differentiation of human mesenchymal stem cells (hMSCs) was quantified by measuring alkaline phosphatase (ALP) activity and calcium deposition. To evaluate osteoclast differentiation, we investigated the effect of E-2, 5-DHB on RANKL-activated osteoclastogenesis in RAW 264.7 cells. E-2, 5-DHB enhanced ALP activity and inhibited RAW 264.7 cell osteoclastogenesis in vitro. To assess the in vivo activity of E-2, 5-DHB, hMSCs were delivered subcutaneosuly alone or in combination with E-2, 5-DHB in an alginate gel into the backs of nude-mice. Histological and immunohistochemical evaluation showed significantly higher calcium deposition in the E-2, 5-DHB group. Osteocalcin (OCN) was highly expressed in cells implanted in the gels containing E-2, 5-DHB. Our results suggest that E-2, 5-DHB can effectively enhance osteoblast differentiation and inhibit osteoclast differentiation both in vitro and in vivo. Understanding the dual function of E-2, 5-DHB on osteoblast and osteoclast differentiation will aid in future development of E-2, 5-DHB as a material for bone tissue engineering.

Developing the Korean Association of Medical Colleges graduate outcomes of basic medical education based on "the role of Korean doctor, 2014".

The Korean Association of Medical Colleges (KAMC) developed graduate outcomes based on "The role of Korean doctor, 2014" to serve as guidelines regarding outcome-based education in Korea. The working group in this study analyzed 65 competencies proposed in "The role of Korean doctor, 2014" according to the developmental principle that certain outcomes should be demonstrated at the point of entry into the graduate medical education. We established 34 competencies as "preliminary graduate outcomes" (PGOs). The advisory committee consisted of 11 professors, who reviewed the validity of PGOs. Ultimately, a total of 19 "revised graduate outcomes" (RGOs) were selected. We modified the RGOs based on opinions from medical schools and a public hearing. In November 2017, the KAMC announced the "graduate outcomes for basic medical education," which serves as a guide for basic medical education for the 40 medical schools throughout Korea. Medical schools can expand the graduate outcomes according to their educational goals and modify them according to their own context. We believe that graduate outcomes can be a starting point for connecting basic medical education to graduate medical education.

[Students' perception of the educational environment of medical schools in Korea: findings from a nationwide survey].

PURPOSE: The purpose of this study was to examine students' perception of the educational environment of medical schools in Korea. METHODS: A total of 9,096 of 12,035 students (75.6%) responded to our questionnaire. This study was conducted at the end of the 2013 academic year using the Dundee Ready Education Environment Measure (DREEM) at 40 medical schools in Korea. DREEM comprises five domains: students' perceptions of learning (SPL); students' perceptions of teachers (SPT); students' academic self-perceptions; students' perceptions of atmosphere; and students' social self-perception. The data were analyzed using descriptive statistics, independent t-test, and one-way analysis of variance. RESULTS: The overall mean DREEM score was 113.97 (of 200), and the scores for the 40 medical schools ranged from 100.24 to 134.32. The overall mean and domains scores of the DREEM differed significantly between educational systems, grades, genders, and academic achievement levels. Graduate-level medical students had higher scores for the DREEM and its five domains than undergraduate medical students. The scores were lowest in second-year students (mean, 111.80). Male students' perceptions were significantly higher than those of female students except for SPL and SPT. High academic achievers' perceptions were also greater versus low academic achievers. CONCLUSION: Students' perceptions of their educational environment are positive in Korea. The learning environment should be evaluated by curriculum planners and administrators of medical schools to improve its quality.

Staged biventricular repair of Taussig-Bing anomaly with subaortic stenosis and coarctation of aorta.

We present successful procedures for 2 infants who had the Taussig-Bing anomaly with subaortic stenosis and coarctation of the aorta. The initial procedure was coarctoplasty and the Damus-Kaye-Stansel procedure with modified Blalock-Taussig shunt. The second procedure was intraventricular repair (Kawashima procedure), Damus-Kaye-Stansel take-down and the reuse of native aortic and pulmonary valves 19 and 25 months later. Both patients survived the operations and postoperative hemodynamics were excellent at both 28 and 59 months follow-ups.

Ethyl-3,4-dihydroxybenzoate with a dual function of induction of osteogenic differentiation and inhibition of osteoclast differentiation for bone tissue engineering.

The current approach in biomaterial design of bone implants is to induce in situ regeneration of bone tissue, thus improving integration of the implants and reducing their failure. Therefore, ethyl-3,4-dihydroxybenzoate (EDHB), which stimulates differentiation of osteoblasts and the resultant bone formation, should be studied. In this study, the osteoinductive ability of EDHB in preosteoblasts and human mesenchymal stem cells was examined. EDHB for future use in bone tissue engineering was evaluated by examination of early markers of differentiation (such as alkaline phosphatase [ALP] activity and collagen type I expression) and late markers of osteoblast differentiation (bone nodule formation). As bone remodeling and implant osteointegration depend not only on osteoblast response but also on interaction of the biomaterial with bone-resorbing osteoclasts, differentiation of osteoclasts in response to the compounds was also observed. For in vivo study, alginate gel comprised of EDHB and cells was transplanted into the back subcutis of mice. Our results show that EDHB might have beneficial effects through regulation of both osteoblast and osteoclast differentiation. Therefore, we suggest that EDHB could be a strong candidate for dual regulation to increase osteoblast differentiation and decrease osteoclast differentiation.

[Equating scores using bridging stations on the clinical performance examination].

PURPOSE: This study examined the use of the Tucker linear equating method in producing an individual student's score in 3 groups with bridging stations over 3 consecutive days of the clinical performance examination (CPX) and compared the differences in scoring patterns by bridging number. METHODS: Data were drawn from 88 examinees from 3 different CPX groups-DAY1, DAY2, and DAY3-each of which comprised of 6 stations. Each group had 3 common stations, and each group had 2 or 3 stations that differed from other groups. DAY1 and DAY3 were equated to DAY2. Equated mean scores and standard deviations were compared with the originals. DAY1 and DAY3 were equated again, and the differences in scores (equated score-raw score) were compared between the 3 sets of equated scores. RESULTS: By equating to DAY2, DAY1 decreased in mean score from 58.188 to 56.549 and in standard deviation from 4.991 to 5.046, and DAY3 fell in mean score from 58.351 to 58.057 and in standard deviation from 5.546 to 5.856, which demonstrates that the scores of examinees in DAY1 and DAY2 were accentuated after use of the equation. The patterns in score differences between the equated sets to DAY1, DAY2, and DAY3 yielded information on the soundness of the equating results from individual and overall comparisons. CONCLUSION: To generate equated scores between 3 groups on 3 consecutive days of the CPX, we applied the Tucker linear equating method. We also present a method of equating reciprocal days to the anchoring day as much as bridging stations.

Comprehension of Patient-Physician Interaction through Analysis of Relationships between Domains in Clinical Performance Examination.

PURPOSE: This research investigated the psychometric properties of the patient-physician interaction (PPI) domain in the clinical performance examination (CPX). This research aimed to understand the PPI domain in the CPX through a psychometric and relationship analysis between the domains. METHODS: Data were drawn from 1,302 examinees on a set of 6 common CPX cases and 1,066 on a 'bad news delivery' case. All cases included 7 PPI items, among which we calculated internal consistency reliability. Correlations were made between PPI and the other domains. Analyses using the structural equation model (SEM) were conducted to assess the relationships between latent factors and controlled measurement errors. To calculate the disparity between colleges, we performed a multi-level analysis. Also, we conducted t-tests to investigate the consistency of the PPI and information sharing (IS) scores in the 'bad news delivery' case. RESULTS: Correlation between the mean PPI score and the total CPX score was high (0.707). The correlations between PPI and other domains were; 0.904 for the patient's overall satisfaction, 0.41 for history taking, and 0.327 for patient education. In SEM, these correlations between latent variables increased. The proportion of level-2 (between-school component) variance in PPI was 4.1%. For 'bad news delivery', the group that checked 'yes' on the IS items had higher PPI scores (mostly p<0.01). CONCLUSION: PPI is an influential domain of the CPX and is highly related with the patient's overall satisfaction, clinical courtesy, and history taking. Disparities between schools in PPI are relatively small, such that the PPI could be due to individual factors rather than the school.

Analytical case study of evaluation of curriculum at a medical school.

PURPOSE: This study aims at to make intermediate-term evaluations of a curriculum by investigating its development, operation and outcomes 2 years after its revision. METHODS: A survey using 5-point-Lickert scale questionnaires was given to the group of directors who developed the curriculum, instructors who only used it in their classes, and a student group from the first and second grades. Focus group interviews were performed in the professor groups. RESULTS: Curricular reform was evaluated as being systematic, democratic, and positive in general. Both groups answered questions positively about the relevance of the integrated curriculum and introduction of clinical medicine (ICM), graded as 3.4 (professor) and 3.5 (student). As for problem-based learning (PBL) and the patient-doctor-society (PDS), the professor group responded more positively than students. The 'web-based learning center' was recognized positively by many more students (4.01) than professors (2.75). With regard to the education outcome, professors gave 3.3 points and students 3.5 to an item that asked 'whether students attained the learning goal or not?' Professors, through interviews, showed their satisfaction with the attempt to reform the curriculum, but they pointed out that long-term evaluations should be performed. CONCLUSION: The interim evaluation of the revised curriculum, from its planning to its effects, affirmed by several suggestions to be successful in the long run through 1) enhancement of systematic participation and communication, 2) further integration, 3) steady evaluation, 4) greater effort on professional development, and 5) active interaction between professors and students.

An experimental comparison of rater performance on an SP-based clinical skills exam.

BACKGROUND: Research has provided only limited information regarding how best to structure rater training and the best rating formats for a standardized-patient (SP) based assessment. PURPOSE: The purpose of this study was to determine the efficacy of rater discussions as an expert rater training method and to compare the expert's rating of recorded video performances with real-time SP ratings on both a global and checklist evaluation instrument. METHODS: We implemented an experimental study of a discussion-based expert rater training method to compare generalizability and interrater reliability of trained experts, untrained experts, and SP raters in a 4th-year clinical skills exam. RESULTS: In terms of reliability, SP raters did as well as expert raters on the checklist and better than expert raters on global ratings. For the expert raters, training via a discussion method did not significantly improve the reliability of checklist ratings or global ratings. Within the experts groups, those with checklists performed better than those with global ratings. CONCLUSIONS: For SP-based exams designed to assess basic clinical skills, SP ratings appear to perform as well or better than expert ratings. Discussion-based expert training yielded no improvements in expert rater performance, and expert checklist scores generated more reliable results than the expert global rating scores.

Doppler flow velocity measurement to assess changes in inotropy and afterload: a study in healthy dogs.

Myocardial contractility and afterload are important factors for adequate circulation. To noninvasively assess changes in inotropy and afterload, ascending aortic blood flow was measured by continuous-wave Doppler echocardiography before and after the administration of an inotrope and a vasodilator in eight open chest dogs. Data were collected in the baseline, at three different doses of epinephrine (0.1, 0.5, and 1 microg/kg/min) and nitroprusside (1, 4, and 8 microg/kg/min) administration, and after a simultaneous infusion of both drugs in various combinations. Epinephrine infusion caused increases in peak velocity (PV), mean acceleration (MA), velocity time integral (VTI), and minute distance without a significant change in afterload. Acceleration time (AT) and ejection time (ET) showed a slight tendency to decrease with an increase in inotropy, but with no significance. Nitroprusside infusion produced dose-dependent decreases in blood pressure and index of systemic vascular resistance (ISVR), which was associated with increases in PV, MA, and minute distance, and with a decrease in AT. The combined infusion of nitroprusside and epinephrine, unless ISVR was elevated, produced synergistic effects on PV, MA, VTI, and minute distance. However, these Doppler parameters tended to diminish with an elevation in afterload. ISVR obtained during nitroprusside infusion had a better correlation with both PV and MA than with VTI or the Doppler time intervals. Our study suggests that Doppler measurement of aortic blood flow velocity and acceleration can be used for the noninvasive assessment of changes in inotropy and afterload.

Pediatric cardiac surgery with echocardiographic diagnosis alone.

The diagnostic accuracy of echocardiography alone and the safety of cardiac surgery using this diagnostic approach were retrospectively assessed in 111 children operated for congenital heart defects (CHD) during a 3.5-yr period ending in October 2001. Preoperative diagnosis was compared with the intraoperative findings obtained by surgical inspection. Perioperative death was defined as death within 30 days postoperatively. Of the patients, 70% were operated on in infancy. Seventy-six percent (84 of 111) underwent surgery after echocardiographic diagnosis alone. A high percentage of patients with patent ductus arteriosus (100%), partial atrioventricular canal (100%), coarctation of the aorta (89%), ventricular septal defect (86%), atrial septal defect (85%), and total anomalous pulmonary venous connection (75%) was operated without prior catheterization. Diagnostic errors occurred in 2.4% (2 of 84) of patients with echocardiography only and in 7.4% of patients with catheterization. No error in either group was related to surgical morbidity or mortality. There were five (6.0%) perioperative deaths in the echocardiography group and two (7.4%) in the catheterization group, with no difference in the mortality between the groups. In conclusion, many patients with CHD can be accurately diagnosed by echocardiography alone, and can safely undergo surgery without catheterization, not increasing the overall risk.

Early result of arteriovenous graft with deep forearm veins as an outflow in hemodialysis patients.

The purpose of this study was to evaluate the result of arteriovenous (A-V) grafting with the deep forearm veins as an outflow system in hemodialysis patients. Between June 1999 and July 2001, 27 A-V grafts consisting of ePTFE and deep forearm veins were constructed in 26 patients. All patients followed up for assessment of all relevant values, and the median follow-up period was 17.3 months. Seven grafts (26%) failed during the follow-up. The patency rates were 93% and 80% at 3 months and 12 months, respectively. No difference in patency rate was found between males and females, or between diabetics and nondiabetics. Graft-related complications, excluding graft thrombosis, occurred in five patients. These included operative wound dehiscence in two cases, a graft infection, a seroma, and a mild hypoperfusion in the hand. We conclude that the early patency rate of A-V graft using the forearm deep veins as an outflow system is very good and that this technique may be a recommended surgical modality for vascular access in patients with exhausted superficial veins.