No abstract available.
Animals ; Dogs* ; Lactic Acid*

BACKGROUND/AIMS: Biliary epithelial cells are exposed to highly concentrated oxysterols. Therefore, oxysterols may play a role in pathogenesis of biliary tract diseases. We investigated the cytotoxic effect and apoptosis inducing effect of oxysterol on gallbladder epithelial cells. METHODS: We studied the cytotoxic effect of 3,5- cholestadien-7-one, 5beta-cholestan-3-one and 5,24-cholestadien-3beta-OL which are identified in human bile and pigment gallstones on dog gallbladder epithelial cells (DGBE) and mouse gallbladder epithelial cells (MGBE). We used model bile to dissolve oxysterols as in vitro experiment and also used MTT, cell count, Diff-Quick stain, and flow cytometry to investigate cytotoxicity and apoptosis. RESULTS: Oxysterols dissolved in model bile have cytotoxic effects in a dose dependent fashion. In oxysterol containing model bile, viable cells are 51% in 500 microM 5beta-cholestan-3-one (cholesterol : oxysterol 50:50) and 47% in 5 mM 3,5-cholestadien-7-one (90:10) on MGBE, and are 129% and 38% in 500 microM (50:50) 3,5-cholestadien-7-one and 5beta-cholestan-3-one on DGBE, and are 74% and 71.5% in 5 mM (90:10) 3,5-cholestadien-7-one and 5beta-cholestan-3-one on DGBE, respectively. 500 microM (50:50) 3,5- cholestadien-7-one, 5beta-cholestan-3-one, and 5,24-cholestadien-3beta-OL treated on DGBE increase the apoptotic cell number as 22.0+/-8.8, 30.2+/-12.6, and 45.5+/-13.2%, respectively, compared with control (14.6+/-10.0%). 500 microM (50:50) 3,5-cholestadien-7-one, 5beta-cholestan-3-one, and 5,24-cholestadien-3beta-OL also affect the changes in cell cycles compared with the control. CONCLUSIONS: We concluded that oxysterol containing model bile is useful as an in vitro experiment as model to analyze the effects of oxysterols on biliary epithelial cells and that adequate concentration of oxysterols can induce the cytotoxic effect and the apoptosis on gallbladder epithelial cells.
Animals ; Apoptosis/*drug effects ; Bile/chemistry ; Cholestadienes/*toxicity ; Cholestadienols/*toxicity ; Cholestanes/*toxicity ; Dogs ; Dose-Response Relationship, Drug ; English Abstract ; Epithelial Cells/*drug effects ; Gallbladder/*cytology/drug effects ; In Vitro ; Rats

We use the concept of the “doctor’s role” as a guideline for developing medical education programs for medical students, residents, and doctors. Therefore, we should regularly reflect on the times and social needs to develop a clear sense of that role. The objective of the present study was to understand the knowledge structure related to doctor’s job competencies in Korea. We analyzed research trends related to doctor’s job competencies in Korea Citation Index journals using text network analysis through an integrative approach focusing on identifying social issues. We finally selected 1,354 research papers related to doctor’s job competencies from 2011 to 2020, and we analyzed 2,627 words through data pre-processing with the NetMiner ver. 4.2 program (Cyram Inc., Seongnam, Korea). We conducted keyword centrality analysis, topic modeling, frequency analysis, and linear regression analysis using NetMiner ver. 4.2 (Cyram Inc.) and IBM SPSS ver. 23.0 (IBM Corp., Armonk, NY, USA). As a result of the study, words such as “family,” “revision,” and “rejection” appeared frequently. In topic modeling, we extracted five potential topics: “topic 1: Life and death in medical situations,” “topic 2: Medical practice under the Medical Act,” “topic 3: Medical malpractice and litigation,” “topic 4: Medical professionalism,” and “topic 5: Competency development education for medical students.” Although there were no statistically significant changes in the research trends for each topic over time, it is nonetheless known that social changes could affect the demand for doctor’s job competencies.

BACKGROUND: The causes of hepatic dysfunction after exposures to the halogenated inhaled anesthetics may be free radical, metabolites of inhaled anesthetics, immune reaction and hypoxic damage by decreasing total hepatic blood flow. The present study was performed to comparison of estimated hepatic blood flow and systemic hemodynamic changes between the general anesthesia with enflurane and thoracic epidural anesthesia in rabbits. METHODS: In general anesthesia group with enflurane, anesthesia was performed with enflurane 2vol% and 100% oxygen for 60 minutes. In thoracic epidural anesthesia group, epidural block was done at T5 level with 0.4 ml/kg of 1% lidocaine. Hepatic blood flow was estimated by clearance of indocyanine green according to the constant infusion method before and 30, 60 minutes after anesthesia. Heart rate, mean arterial pressure, central venous pressure and splanchnic vascular resistance were measured at the same time in both groups. RESULTS: Heart rate was decreased significantly in thoracic epidural anesthesia group and mean arterial pressure and central venous pressure were decreased significantly in both groups at 30, 60 minutes. Hepatic blood flow was decreased at 30, 60 minutes in both groups. Splanchnic vascular resistance was increased significantly 30, 60 minutes in thoracic epidural anesthesia group. There were significant differences in mean arterial pressure and splanchnic vascular resistance between two groups. There was no difference in hepatic blood flow between two groups. CONCLUSIONS: The decreased hepatic blood flow was caused by decreased mean arterial pressure in general anesthesia group with enflurane and by increased splanchnic vascular resistance in thoracic epidural anesthesia group.
Anesthesia ; Anesthesia, Epidural ; Anesthesia, General ; Anesthetics ; Arterial Pressure ; Central Venous Pressure ; Enflurane ; Heart Rate ; Hemodynamics* ; Indocyanine Green ; Lidocaine ; Oxygen ; Rabbits ; Vascular Resistance

Radiofrequency catheter ablation (RFCA) is a useful treatment for drug-refractory atrial fibrillation. RFCA can cause cerebral infarction that remains the neurologic deficit if prompt managements are delayed. We report on 3 patients who developed cerebral infarctions immediately after RFCA. Periprocedural anticoagulation such as warfarin should be continued for patients, even if they are at low risk for cerebral infarction.
Atrial Fibrillation* ; Catheter Ablation* ; Cerebral Infarction* ; Humans ; Neurologic Manifestations ; Warfarin

PURPOSE: The effects of fiber alignment and direction of mechanical strain on the ECM generation of human ACL fibroblast were assessed. MATERIALS AND METHODS: The aligned nanofiber was fabricated using electrospinning with a rotating target. The amounts of collagen on aligned and randomly oriented structures were compared. To evaluate the effect of strain direction, 5% uniaxial strain (0.2 Hz) was applied to fibroblasts seeded on parallel aligned, vertically aligned to the strain direction, and randomly oriented nanofiber sheets. The amounts of collagen produced were measured 2 days after halting the strain application. RESULTS: The fibroblasts on the aligned nanofiber were spindle-shaped and oriented in the direction of the fibers. Significantly more collagen (22.5+/-2.7 ug/ngDNA) was synthesized on the aligned nanofiber than the randomly oriented (14.5+/-3.2 ug/ngDNA). And the amounts of collagen produced were increased by 150% and 50% approximately with the longitudinal and perpendicular cyclic strain, respectively. CONCLUSION: The aligned nanofiber scaffold used in this study constitutes a promising base material for tissue-engineered ligament in that it provides a more biomimetic structure, including the preferable mechanical environment.
Biomimetics ; Collagen ; Fibroblasts* ; Humans* ; Ligaments ; Nanofibers*

Study on the Potential of Hydroxapatite Based Bioactive Bone Cement PURPOSE: The purpose of this study is to propose a new bioactive bone cement (BBC) composed of bone powder (hydroxyapatite; HA), chitosan powder, and currently available polymethylmethacrylate (PMMA) bone cement for use in orthopaedic surgeries such as vertebroplasty or bone filler. MATERIALS AND METHODS: Three types of proposed BBCs and a currently available commercial PMMA were tested. In vitro studies the surface morphology, chemical composition, changes in pH value along the time, exothermic temperatures, intrusion and cellular responses were investigated. SEM, radiological and histological examinations were performed in animal studies. RESULTS: The major components of BBCs were C, O, Ca, P, Cl, Si, S, Ba and Mg. The pH values in BBCs decreased after 1 day, however they eventually reached 7.2-7.4. The water absorbency, weight loss, and porosity in BBCs increased more than PMMA more than during degradation (p<0.05). However, the compressive Young's moduli and ultimate compressive strength (UCS) of BBCs were lower than those of PMMA (<0.05). The exothermic temperatures of the BBCs were considerably lower than that of PMMA (p<0.05). In view of setting time, it takes relatively longer for BBCII and III to be solidified than PMMA (p<0.05). The intrusion tests showed that the BBCs were more intrusive than PMMA (p<0.05). The cell proliferation test on BBCII showed that the BBCII was more preferable than the PMMA. No cytotoxic characteristics were found in all BBCs. In the animal test, BBC II was more biocompatible as well as osteoconductible than the PMMA. CONCLUSION: The results of in vitro and animal studies indicated that the proposed BBCs have a potential of clinical application as replacement of the current PMMA bone cements.
Animals ; Bone Cements ; Cell Proliferation ; Chitosan ; Compressive Strength ; Durapatite* ; Hydrogen-Ion Concentration ; Polymethyl Methacrylate ; Porosity ; Vertebroplasty ; Water ; Weight Loss

PURPOSE: To evaluate the feasibility of simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) for preoperative concurrent chemoradiotherapy (PCRT) in locally advanced rectal cancer (LARC), by comparing with 3-dimensional conformal radiotherapy (3D-CRT). MATERIALS AND METHODS: Patients who were treated with PCRT for LARC from 2015 January to 2016 December were retrospectively enrolled. Total doses of 45 Gy to 50.4 Gy with 3D-CRT or SIB-IMRT were administered concomitantly with 5-fluorouracil plus leucovorin or capecitabine. Surgery was performed 8 weeks after PCRT. Between PCRT and surgery, one cycle of additional chemotherapy was administered. Pathologic tumor responses were compared between SIB-IMRT and 3D-CRT groups. Acute gastrointestinal, genitourinary, hematologic, and skin toxicities were compared between the two groups based on the RTOG toxicity criteria. RESULTS: SIB-IMRT was used in 53 patients, and 3D-CRT in 41 patients. After PCRT, no significant differences were noted in tumor responses, pathologic complete response (9% vs. 7%; p = 1.000), pathologic tumor regression Grade 3 or higher (85% vs. 71%; p = 0.096), and R0 resection (87% vs. 85%; p = 0.843). Grade 2 genitourinary toxicities were significantly lesser in the SIB-IMRT group (8% vs. 24%; p = 0.023), but gastrointestinal toxicities were not different across the two groups. CONCLUSION: SIB-IMRT showed lower GU toxicity and similar tumor responses when compared with 3D-CRT in PCRT for LARC.
Capecitabine ; Chemoradiotherapy* ; Drug Therapy ; Fluorouracil ; Humans ; Leucovorin ; Neoadjuvant Therapy ; Radiotherapy, Conformal* ; Radiotherapy, Intensity-Modulated* ; Rectal Neoplasms* ; Retrospective Studies ; Skin

PURPOSE: To evaluate the feasibility of simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) for preoperative concurrent chemoradiotherapy (PCRT) in locally advanced rectal cancer (LARC), by comparing with 3-dimensional conformal radiotherapy (3D-CRT). MATERIALS AND METHODS: Patients who were treated with PCRT for LARC from 2015 January to 2016 December were retrospectively enrolled. Total doses of 45 Gy to 50.4 Gy with 3D-CRT or SIB-IMRT were administered concomitantly with 5-fluorouracil plus leucovorin or capecitabine. Surgery was performed 8 weeks after PCRT. Between PCRT and surgery, one cycle of additional chemotherapy was administered. Pathologic tumor responses were compared between SIB-IMRT and 3D-CRT groups. Acute gastrointestinal, genitourinary, hematologic, and skin toxicities were compared between the two groups based on the RTOG toxicity criteria. RESULTS: SIB-IMRT was used in 53 patients, and 3D-CRT in 41 patients. After PCRT, no significant differences were noted in tumor responses, pathologic complete response (9% vs. 7%; p = 1.000), pathologic tumor regression Grade 3 or higher (85% vs. 71%; p = 0.096), and R0 resection (87% vs. 85%; p = 0.843). Grade 2 genitourinary toxicities were significantly lesser in the SIB-IMRT group (8% vs. 24%; p = 0.023), but gastrointestinal toxicities were not different across the two groups. CONCLUSION: SIB-IMRT showed lower GU toxicity and similar tumor responses when compared with 3D-CRT in PCRT for LARC.
Capecitabine ; Chemoradiotherapy* ; Drug Therapy ; Fluorouracil ; Humans ; Leucovorin ; Neoadjuvant Therapy ; Radiotherapy, Conformal* ; Radiotherapy, Intensity-Modulated* ; Rectal Neoplasms* ; Retrospective Studies ; Skin

PURPOSE: Insulin-like growth factors (IGF) regulate a wide range of biological functions including cell proliferation, differentiation, and apoptosis through paracrine and autocrine mechanisms. Accordingly, the present study analyzed polymorphisms of IGF genes and their impact on the prognosis for patients with colorectal cancer. MATERIALS AND METHODS: Four hundred and two consecutive patients with curatively resected colorectal adenocarcinoma were enrolled in the present study. The genomic DNA was extracted from fresh colorectal tissue and 8 polymorphisms of IGF genes determined using a real-time polymerase chain reaction genotyping assay. RESULTS: Pathologic stages after surgery were as follows: stage 0/I (n=85, 21.1%), stage II (n=147, 36.6%), stage III (n=145, 36.1%), and stage IV (n=25, 6.2%). Multivariate survival analysis including stage, age, site of disease, and carcinoembryonic antigen level showed that the progression-free survival for patients with the IGF2 +1280 GG genotype was slightly better than for the patients with the combined IGF2 +1280 AA and AG genotype (p=0.056), although there was no significant difference in the overall survival. However, the other polymorphisms were not associated with survival. CONCLUSION: None of the 8 IGF1 or IGF2 gene polymorphisms investigated in this study were found to be independent prognostic markers for Korean patients with surgically resected colorectal cancer.
Adenocarcinoma ; Apoptosis ; Carcinoembryonic Antigen ; Cell Proliferation ; Colorectal Neoplasms ; Disease-Free Survival ; DNA ; Genotype ; Humans ; Polymorphism, Genetic ; Prognosis ; Real-Time Polymerase Chain Reaction ; Somatomedins