Juhyun Park

Tissue-engineered heart valve leaflets: an animal study.

Background Tissue-engineered heart valve leaflets are a promising way to overcome the inherent limitations of current prosthetic valves. The aim of this study was to compare the biological responses of an autologous cell seeded scaffold and an acellular scaffold implanted in the pulmonary valve leaflet in the same animal. Methods Myofibroblasts and endothelial cells were isolated and cultured from an ovine artery. A synthetic biodegradable scaffold consisting of polyglycolic acid and polylactic acid was initially seeded with the myofibroblasts, then coated with endothelial cells. Cells were seeded using a medium containing collagen and cultured. A tissue-engineered construct and a plain scaffold were implanted as double pulmonary valve leaflet replacement in the same animal in an ovine model (n=3). Additionally, the tissue-engineered construct (n=2) and the plain scaffold (n=2) were implanted as single valve leaflet replacements for long-term analysis. After sacrifice, the implanted valve leaflet tissues were retrieved, analyzed visually and using light microscopy. Results Three animals that underwent replacement of two valve leaflets with a tissue-engineered construct and a plain scaffold, survived only a short-time (12, 24, 36 hours). The death was attributed to heart failure caused by severe pulmonary insufficiency. Animals that underwent single valve leaflet replacement survived longer and were electively sacrificed at 6 and 9 weeks after operation. The analysis of the leaflets from the short-term survivors showed that the tissue-engineered constructs contained less fibrins and protein exudates than the plain scaffold. In contrast, leaflets obtained from animals surviving 6 and 9 weeks showed similar well organized granulation tissues in the tissue-engineered constructs and the plain scaffolds. Conclusion This animal experiment demonstrates that in the early phase of implantation, the tissue-engineered construct shows a better biological response in terms of antithrombogenicity than the plain scaffold, although both of them have similar results in the later reparative phase.

Low testosterone level is an independent risk factor for high-grade prostate cancer detection at biopsy.

To investigate the relationship between low testosterone levels and prostate cancer detection risk in a biopsy population.

Tissue-engineered heart valve leaflets: an effective method for seeding autologous cells on scaffolds.

Background A precondition for the successful formation of tissue-engineered heart valves is the generation of a proper matrix on biodegradable scaffolds over a limited period of time. The aim of this study was to find an effective method of seeding autologous cells on these scaffolds to create a new matrix for heart valves. Methods Myofibroblasts and endothelial cells were isolated and cultured from an ovine artery. A synthetic biodegradable scaffold consisting of polyglycolic and polylactic acids was seeded first with the myofibroblasts, then coated with endothelial cells. Three different methods of myofibroblast seeding were compared: I) daily seeding of myofibroblasts (1×106) for ten days and culture for four days; II) seeding of myofibroblasts (1×107) and culture for 14 days with the use of a simple medium; III) seeding of myofibroblasts (1×107) with the use of a medium containing collagen and culture for 14 days. Light and electron microscopic analyses were perfomed. Results The group that used the medium containing collagen showed the best results in terms of seeding efficiency. Conclusion Seeding autologous cells with a medium containing collagen onto the scaffold showed the largest cell population and might generate the best matrix on the scaffold.

The association between alexithymia and posttraumatic stress symptoms following multiple exposures to traumatic events in North Korean refugees

OBJECTIVE The present study aimed to investigate the effect of the interaction between the number of traumas experienced and alexithymia, on posttraumatic stress disorder (PTSD) symptoms. METHODS The sample comprised 199 North Korean refugees. Participants completed the Trauma Exposure Check List for North Korean Refugees, Impact of Event Scale-Revised (IES-R), Toronto Alexithymia Scale-20 (TAS-20), and Center for Epidemiological Studies-Depression Scale (CES-D). RESULTS TAS-20 scores were positively correlated with IES-R scores (r=0.21, p<0.01), after controlling for gender, age, and CES-D scores. The number of traumas experienced was also positively correlated with IES-R scores (r=0.32, p<0.001), but not with TAS-20 scores, after controlling for gender, age, and CES-D scores. A hierarchical multiple regression analysis revealed a significant interaction between the number of traumas experienced and TAS-20 scores, for IES-R scores (t=2.10, p<0.05). Moderation analysis further revealed that TAS-20 scores moderate the relationship between the number of traumas experienced and IES-R scores (t=2.90, p<0.01). For refugees with higher TAS-20 scores, those who had experienced more traumas had higher IES-R scores. However, within refugees with lower TAS-20 scores, IES-R scores were not significantly different for those who had experienced a higher number of traumas compared with those who had experienced a lower, or average, number of traumas. CONCLUSION The results of the current study suggest that, as individuals experience more traumatic events, clearly identifying and expressing emotions become more crucial for reducing PTSD symptoms.

Obesity is associated with higher risk of prostate cancer detection in a biopsy population in Korea.

To evaluate the impact of obesity on prostate cancer detection, as measured by the body mass index (BMI) in a Korean biopsy population.

Impact of Detrusor Underactivity on Surgical Outcomes of Laser Prostatectomy: Comparison in Serial 12-Month Follow-Up Outcomes Between Potassium-Titanyl-Phosphate Photoselective Vaporization of the Prostate (PVP) and Holmium Laser Enucleation of the Prostate (HoLEP)

OBJECTIVE To evaluate impacts of preoperative detrusor underactivity (DU) on outcomes of photoselective vaporization of the prostate (PVP) or holmium laser enucleation of the prostate (HoLEP) for benign prostatic hyperplasia, and to compare them between the two surgeries. MATERIALS AND METHODS A total of 1423 men, who underwent PVP (group A) or HoLEP (group B), were categorized into four groups: A1 (239 without DU), A2 (432 with DU), B1 (329 without DU), and B2 (423 with DU). DU was defined as bladder contractility index of <100. Outcomes were assessed at 1, 3, 6, and 12 months postoperatively using International Prostate Symptom Score (IPSS), uroflowmetry, and prostate-specific antigen. Successful outcome was defined as reductions by ≥50% of total IPSS at 12 months postoperatively. RESULTS In all four groups, almost all parameters of IPSS and uroflowmetry improved starting from 1 month. A1 or B1 had greater increases in maximum flow rate than A2 or B2. Decreases of total IPSS in A2 were less than in A1 starting from 1 month after PVP, whereas those in B2 were less than those in B1 as late as 12 months after HoLEP. B2 showed greater improvements in maximum flow rate, subtotal voiding symptom score, bladder voiding efficiency, and total IPSS than A2. In all patients, multivariate regression analysis revealed that the absence of DU, presence of bladder outlet obstruction, and higher baseline total IPSS were independent predictors of successful outcome after surgery, but the type of laser surgery (PVP vs HoLEP) was not. CONCLUSION Our data suggest that micturition symptoms, maximum flow rate, bladder voiding efficiency, and quality of life improve starting from the early period after PVP or HoLEP, irrespective of DU. However, patients with DU may have less degree of improvement in micturition after PVP or HoLEP than those without DU.

Decreased regional gray matter volume in suicide attempters compared to suicide non-attempters with major depressive disorders

OBJECTIVE This study investigated regional gray matter (GM) volume differences between suicide attempters and suicide non-attempters with major depressive disorder (MDD) and their relationship with psychological risk factors for suicidality. METHODS MDD patients with and without a suicide attempt history (n=19 in each group) participated. The Hamilton Depression Rating Scale, Clinical Global Impression (severity subscale), Scale for Suicide Ideation (SSI), Risk-Rescue Rating (RRR), Beck Hopelessness Scale (BHS), Barrett Impulsivity Scale, Eysenck Personality Questionnaire, and Ways of Coping Checklist (WCCL) were administered. T1-weighted structural magnetic resonance imaging scans were acquired to evaluate changes in GM volume. Voxel-based morphometry was performed using the SPM 8 software package. Two-sample t-tests were used during second-level group comparison analysis; partial correlation analysis controlling for gender and age identified associations between regional GM volume and psychological measures. RESULTS Suicide attempters exhibited significantly decreased GM volume in the left angular gyrus (p<0.001, uncorrected) and right cerebellum (p<0.001, uncorrected). GM volume in the left angular gyrus was inversely correlated with BHS scores (r=-0.55, p<0.01) and positively correlated with the Seeking Social Support subscale of the WCCL (r=0.43, p<0.01). CONCLUSION These findings provide evidence of a neural basis of suicidal behaviors in MDD. In particular, reduced GM volume in the left angular gyrus may be a neurobiological marker of suicidality in depressed patients.

Academic performance among adolescents with behaviorally induced insufficient sleep syndrome.

STUDY OBJECTIVES The present study investigated academic performance among adolescents with behaviorally induced insufficient sleep syndrome (BISS) and attempted to identify independent predictors of academic performance among BISS-related factors. METHODS A total of 51 students with BISS and 50 without BISS were recruited from high schools in South Korea based on self-reported weekday sleep durations, weekend oversleep, and the Epworth Sleepiness Scale (ESS). Participants reported their academic performance in the form of class quartile ranking. The Korean version of the Composite Scale (KtCS) for morningness/eveningness, the Beck Depression Inventory (BDI) for depression, and the Barratt Impulsiveness Scale-II (BIS-II) for impulsivity were administered. RESULTS Adolescents with BISS reported poorer academic performance than adolescents without BISS (p = 0.02). Adolescents with BISS also exhibited greater levels of eveningness (p < 0.001), depressive symptoms (p < 0.001), and impulsiveness (p < 0.01). Longer weekend oversleep predicted poorer academic performance among adolescents with BISS even after controlling for ESS, KtCS, BDI, and BIS-II (β = 0.42, p < 0.01). CONCLUSIONS BISS among adolescents is associated with poor academic performance and that sleep debt, as represented by weekend oversleep, predicts poorer academic performance independent of depression, impulsiveness, weekday sleep duration, daytime sleepiness, and morningness/eveningness among adolescents with BISS.

External Validation and Evaluation of Reliability and Validity of the Modified Seoul National University Renal Stone Complexity Scoring System to Predict Stone-Free Status After Retrograde Intrarenal Surgery

OBJECTIVES The modified Seoul National University Renal Stone Complexity scoring system (S-ReSC-R) for retrograde intrarenal surgery (RIRS) was developed as a tool to predict stone-free rate (SFR) after RIRS. We externally validated the S-ReSC-R. MATERIALS AND METHODS We retrospectively reviewed 159 patients who underwent RIRS. The S-ReSC-R was assigned from 1 to 12 according to the location and number of sites involved. The stone-free status was defined as no evidence of a stone or with clinically insignificant residual fragment stones less than 2 mm. Interobserver and test-retest reliabilities were evaluated. Statistical performance of the prediction model was assessed by its predictive accuracy, predictive probability, and clinical usefulness. RESULTS Overall SFR was 73.0%. The SFRs were 86.7%, 70.2%, and 48.6% in low-score (1-2), intermediate-score (3-4), and high-score (5-12) groups, respectively (p<0.001). External validation of S-ReSC-R revealed an area under the curve (AUC) of 0.731 (95% CI 0.650-0.813). The AUC of the three-titered S-ReSC-R was 0.701 (95% CI 0.609-0.794). The calibration plot showed that the predicted probability of SFR had a concordance comparable to that of observed frequency. The Hosmer-Lemeshow goodness of fit test revealed a p-value of 0.01 for the S-ReSC-R and 0.90 for the three-titered S-ReSC-R. Interobserver and test-retest reliabilities revealed an almost perfect level of agreement. CONCLUSIONS The present study proved the predictive value of S-ReSC-R to predict SFR following RIRS in an independent cohort. Interobserver and test-retest reliabilities confirmed that S-ReSC-R was reliable and valid.

Insomnia in North Korean Refugees: Association with Depression and Post-Traumatic Stress Symptoms

Objective We investigated the prevalence of insomnia and its clinical characteristics in North Korean refugees. Methods North Korean refugees living in South Korea (48 males, 129 females; mean age 38.22±12.24 years) and South Koreans (112 males, 203 females; mean age 39.48±10.32 years) completed the following questionnaires: the Self-reported Questionnaire on Insomnia, Center for Epidemiological Studies-Depression Scale (CES-D), Trauma Exposure Check List for North Korean Refugees, and the Impact of Event Scale-Revised (IES-R). Results North Korean refugees had insomnia more often than South Koreans did (38.42% vs. 8.89%). Depression combined with insomnia was also more prevalent in North Korean refugees (28.25% vs. 3.17%). Compared with South Koreans with insomnia, North Korean refugees with insomnia showed higher CES-D scores. The North Korean refugees with insomnia had experienced a larger number of traumatic events, and had higher CES-D and IES-R scores compared to North Korean refugees without insomnia. Insomnia in North Korean refugees was also associated with the presence of significant depressive and post-traumatic stress disorder (PTSD) symptoms. Conclusion Insomnia was common in North Korean refugees and was closely associated with depressive and PTSD symptoms. Our study suggests that complaints of insomnia may indicate more severe psychopathology, especially in refugees.