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Gallstones are relatively common in the general population, and the clinical presentation is asymptomatic in most patients or has a benign course, such as biliary colic or vague gastrointestinal symptoms. On the other hand, it sometimes causes life-threatening complications, such as cholecystitis and pancreatitis. Asymptomatic gallstones do not require specific treatment, but a cholecystectomy may be necessary if the patient has a high risk of complications or gallbladder cancer. Abdominal ultrasonography is the most useful diagnostic tool for gallstones, which shows high sensitivity and specificity. In addition, endoscopic ultrasonography may be helpful when typical symptoms of gallstones are present, but gallstones are not identified with abdominal ultrasonography. Abdominal CT, MRCP, or ERCP help identify complications or other accompanying diseases caused by gallstones. Oral bile acid dissolution therapy can be attempted by administering ursodeoxycholic acid and chenodeoxycholic acid if gallstones are confirmed, but the related symptoms are mild or atypical, and the patient is unable/unwilling to undergo a cholecystectomy. A high success rate can be achieved when the treatment candidate is appropriately selected. The disadvantages of oral bile acid dissolution therapy are that there are few appropriate candidates, long-term treatment is required, and the gallstone frequently recurs when the treatment is discontinued.
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Objective@#This study aimed to find changes in the job satisfaction of emergency physicians (EP) and suggest ways to objectively measure indicators of satisfaction for future surveys. @*Methods@#A total of 2,138 emergency physicians were surveyed, using email questionnaires from January to February of 2021. The factors related to their job satisfaction were analyzed. @*Results@#Emergency physicians’ satisfaction was low. The average number of times they experienced violence per year was 4.3±4.9 per year. Work intensity and salary satisfaction improved than those in the 2010, and 2015 Korean Emergency Physician Survey (KEPS). Health status, such as drowsiness, and depression rates, were low. Forty-three percentage of EPs said they would reapply for the emergency specialty. @*Conclusion@#Despite the increase in extrinsic indicators, job satisfaction remained low compared to those in the 2010, and 2015 KEPS. To improve job satisfaction, non-quantitative factors should be considered. It would be necessary to evolve a separate survey on job satisfaction and conduct regular surveys in this regard.
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For primary prevention, it is important for public health and clinical medicine to identify and characterize modifiable risk factors of stroke. In existing literature, the impact of occupational variables on ischemic and hemorrhagic stroke has been extensively studied. This review summarizes the available data on the significance of occupational variables in stroke. The results of this review suggest that there is sufficient evidence for the relationship between increased risk of stroke and job stress, working in extreme temperatures, long working hours, and/or shift work. The association between long working hours and occupational exposure to noise and chemicals remains inconclusive although several studies have reported this finding. This review will act as a step toward future research and provide information that may serve as a baseline for developing targeted interventions to prevent stroke in the working population.
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The application of minimally invasive surgery for gallbladder cancer (GBC) is yet controversial. This article discusses the techniques of laparoscopic and robotic extended cholecystectomy. A 69-year-old male diagnosed with cT1-2N0 GBC underwent laparoscopic surgery, and a 55-year-old male with cT2N1 GBC underwent robotic surgery after preoperative chemotherapy. Nonanatomical partial hepatectomy with lymphadenectomy was performed. Liver parenchymal dissection was performed using Cavitron Ultrasonic Surgical Aspirator laparoscopically and Maryland bipolar dissector and Harmonic scalpel robotically. The operation time was 180 and 220 minutes, and the estimated blood loss was 140 and 130 mL, respectively. The final pathologies were pT1bN0 and pT2aN1, for which patients received adjuvant chemotherapy. There was no evidence of recurrence at 33 and 18 months without complications. Both laparoscopic and robotic extended cholecystectomy can be safely performed with the robotic surgical system as an effective alternative for GBC requiring liver resection with radical lymphadenectomy
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Background/Aims@#Although endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) and fine needle biopsy (FNB) are widely used for tissue acquisition of pancreatic solid mass, the optimal strategy of this procedure has not been established yet. The aim of this nationwide study was to investigate the current practice patterns of EUS-FNA/FNB for pancreatic solid mass in Korea. @*Methods@#The Policy-Quality Management of the Korean Pancreatobiliary Association (KPBA) developed a questionnaire containing 22 questions. An electronic survey consisting of the questionnaire was distributed by e-mail to members registered to the KPBA. @*Results@#A total of 101 respondents completed the survey. Eighty respondents (79.2%) performed preoperative EUS-FNA/FNB for operable pancreatic solid mass. Acquire needles (60.4%) were used the most, followed by ProCore needles (47.5%). In terms of need size, most respondents (>80%) preferred 22-gauge needles regardless of the location of the mass. Negative suction with a 10-mL syringe (71.3%) as sampling technique was followed by stylet slow-pull (41.6%). More than three needle passes for EUS-FNA/FNB was performed by most respondents (>80%). The frequency of requiring repeated procedure was significantly higher in respondents with a low individual volume (<5 per month, p=0.001). Prophylactic antibiotics were routinely used in 39 respondents (38.6%); rapid on-site pathologic evaluation was used in 6.1%. @*Conclusions@#According to this survey, practices of EUS-FNA/FNB for pancreatic solid mass varied substantially, some of which differed considerably from the recommendations present in existing guidelines. These results suggest that the development of evidence-based quality guidelines fitting Korean clinical practice is needed to establish the optimal strategy for this procedure.
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Background/Aims@#This study aimed to investigate the patterns of preferred endoscopic procedure types and techniques for managing difficult common bile duct (CBD) stones in South Korea. @*Methods@#The Committee of Policy and Quality Management of Korean Pancreatobiliary Association (KPBA) conducted a survey containing 19 questions. Both paper and online surveys were carried out; with the paper survey being conducted during the 2019 Annual Congress of KPBA and the online survey being conducted through Google Forms from April 2020 to February 2021. @*Results@#The response rate was approximately 41.3% (86/208). Sixty-two (73.0%) worked at tertiary hospitals or academic medical centers, and 60 (69.7%) had more than 5 years of endoscopic retrograde cholangiopancreatography experience. The preferred size criteria for large CBD stones were 15 mm (40.6%), 20 mm (31.3%), and 30 mm (4.6%). For managing of large CBD stones, endoscopic papillary large balloon dilation after endoscopic sphincterotomy was the most preferred technique (74.4%). When performing procedures in those with bleeding diathesis, 64 (74.4%) respondents favored endoscopic papillary balloon dilation (EPBD) alone or EPBD with small endoscopic sphincterotomy. Fifty-five respondents (63.9%) preferred the doubleguidewire technique when faced with difficult bile duct cannulation in patients with periampullary diverticulum. In surgically altered anatomies, cap-fitted forward viewing endoscopy (76.7%) and percutaneous transhepatic cholangioscopy (48.8%) were the preferred techniques for Billroth-II anastomosis and total gastrectomy with Roux-en-Y anastomosis, respectively. @*Conclusions@#Most respondents showed unifying trends for the management of difficult CBD stones. The current practice patterns could be used as basic data for clinical quality improvements in the management of difficult CBD stones.
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Background:Early diagnosis of gallbladder cancer (GBC) which enables to surgical resection is key for improve prognosis. Aim of this study was to investigate clinical features of early GBC patients compare to advanced ones.Methods:We retrospectively reviewed medical records of all pathologically confirmed primary GBC patients between in single tertiary referral center.Results:250 patients (57.3%) were early GBC (stage IandII) and 186 (42.7%) were advanced GBC (stage IIIandIV). Less patients with early GBC had symptom at initial diagnosis (69.2% versus90.8%, p<0.001). Large number of patients with early GBC were diagnosed GBC incidentally after surgical resection which initially suspected benign gallbladder polyp or symptomatic gallbladder stones (71/250, 28.4% versus7/186, 3.8%) (p<0.001). Patients who initially diagnosed gallbladder stone or cholecystitis tended to more advanced than gallbladder polyp.Conclusions:There were no definitive symptoms which can detect early GBCs. Large number of early GBCs were diagnosed incidentally and many of these initially diagnosed with or accompany with benign cholecystic disease. Careful examination should be performed before diagnosis and after treatment, even in patient with vague symptom or benign cholecystic disease without elevated tumor markers.
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Purpose@#The current drain tubes for preventing surgically biliary anastomotic stricture are not naturally and easily removed. If a drain tube using biodegradable material is easily available and the degradation time of the tube is well controlled, surgical anastomotic stricture and fibrosis could be prevented. The aim of this animal study was to evaluate the preventive effect of novel biodegradable stents (BS) on biliary stricture and fibrosis after duct-to-duct (DD) biliary anastomosis. @*Methods@#Ten mini-pigs were allocated to the control group (n = 5) and or the stent group (n = 5). The common bile duct was exposed through surgical laparotomy and then resected transversely. In the stent group, a 4-mm or 6-mm polydioxanone/ magnesium sheath-core BS was inserted according to the width of the bile duct, followed by DD biliary anastomosis. In the control group, DD biliary anastomosis was performed without BS insertion. @*Results@#In the stent group, stents were observed without deformity for up to 4 weeks in all animals. Eight weeks later, histopathologic examination revealed that the common bile duct of the anastomosis site was relatively narrower in circumference in the control group compared to the stent group. The degree of fibrosis in the control group was more marked than in the stent group (3.84 mm vs. 0.68 mm, respectively; P < 0.05). @*Conclusion@#Our study showed that novel BS maintained their original shape and radial force for an adequate time and then disappeared without adverse events. The BS could prevent postoperative complications and strictures after DD biliary anastomosis.
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Objective@#Emergency medicine residents are expected to exhibit a poor health status due to excessive working hours and high stress. Because much of patient care depends on them, their health conditions will have a significant impact on patient outcomes. Our study was designed to analyze the health status of emergency medicine residents and the affecting factors using the 2019 Korean Emergency Medicine Residents Survey (KEMRS) results. @*Methods@#The study evaluated the self-rated health-defined percentage of responders who thought they were in good health. Based on this response, the influencing factors were categorized statistically. These factors included personal characteristics, lifestyle (drinking, smoking, eating, sleeping, and exercise), and emotional stress. @*Results@#Of a total of 384 respondents, 176 (46%) thought they were in good health. Participants who perceived themselves to be unhealthy included residents who were married, female, and those in the 3rd grade. Drinking and smoking were not perceived to affect health status, but regular exercise and proper eating patterns were seen to be positive influencing factors. Daytime sleepiness, depressive moods, and personal well-being were correlated with health status. @*Conclusion@#While personal characteristics and emotional problems cannot be changed easily, lifestyle changes can be made for better health. The health conditions of emergency residents have not been considered a matter of importance thus far. To overcome their health problems, responsible improvements in schedules and a program of long-term follow-ups need to be implemented, followed by training programs.
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Background/Aims@#We examined the efficacy and safety of tegoprazan as a part of first-line triple therapy for Helicobacter pylori eradication. @*Methods@#A randomized, double-blind, controlled, multicenter study was performed to evaluate whether tegoprazan (50 mg)-based triple therapy (TPZ) was noninferior to lansoprazole (30 mg)-based triple therapy (LPZ) (with amoxicillin 1 g and clarithromycin 500 mg; all administered twice daily for 7 days) for treating H. pylori. The primary endpoint was the H. pylori eradication rate. Subgroup analyses were performed according to the cytochrome P450 (CYP) 2C19 genotype, the minimum inhibitory concentration (MIC) of amoxicillin and clarithromycin, and underlying gastric diseases. @*Results@#In total, 350 H. pylori-positive patients were randomly allocated to the TPZ or LPZ group. The H. pylori eradication rates in the TPZ and LPZ groups were 62.86% (110/175) and 60.57% (106/175) in an intention-to-treat analysis and 69.33% (104/150) and 67.33% (101/150) in a per-protocol analysis (non-inferiority test, p=0.009 and p=0.013), respectively. Subgroup analyses according to MICs or CYP2C19 did not show remarkable differences in eradication rate. Both first-line triple therapies were well-tolerated with no notable differences. @*Conclusions@#TPZ is as effective as proton pump inhibitor-based triple therapy and is as safe as first-line H. pylori eradication therapy but does not overcome the clarithromycin resistance of H. pylori in Korea
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Currently, the expanding recreational use of synthetic cannabinoids (SCBs) threatens public health. SCBs produce psychoactive effects similar to those of tetrahydrocannabinol, the main component of cannabis, and additionally induce unexpected pharmacological side effects. SCBs are falsely advertised as legal and safe, but in reality, SCB abuse has been reported to cause acute intoxication and addictive disorders. However, because of the lack of scientific evidence to elucidate their dangerous pharmacological effects, SCBs are weakly regulated and continue to circulate in illegal drug markets. In the present study, the intravenous self-administration (IVSA) paradigm was used to evaluate the abuse potential of three SCBs (AM-1248, CB-13, and PB-22) in rats. All three SCBs maintained IVSA with a large number of infusions and active lever presses, demonstrating their reinforcing effects.The increase of active lever presses was particularly significant during the early IVSA sessions, indicating the reinforcementenhancing effects of the SCBs (AM-1248 and CB-13). The number of inactive lever presses was significantly higher in the SCB groups (AM-1248 and CB-13) than that in the vehicle group, indicating their impulsive effects. In summary, these results demonstrated that SCBs have distinct pharmacological properties and abuse potential.
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Background/Aims@#The mucoprotective drug rebamipide is used to treat gastritis and peptic ulcers. We compared the efficacy of Mucosta Ⓡ (rebamipide 100 mg) and its new formulation, AD-203 (rebamipide 150 mg), in treating erosive gastritis. @*Methods@#This double-blind, active control, noninferiority, multicenter, phase 3 clinical trial randomly assigned 475 patients with endoscopically proven erosive gastritis to two groups: AD-203 twice daily or Mucosta Ⓡ thrice daily for 2 weeks. The intention-to-treat (ITT) analysis included 454 patients (AD-203, n=229; Mucosta Ⓡ , n=225), and the per-protocol (PP) analysis included 439 patients (AD-203, n=224; Mucosta Ⓡ , n=215). The posttreatment assessments included the primary (erosion improvement rate) and secondary endpoints (erosion and edema cure rates; improvement rates of redness, hemorrhage, and gastrointestinal symptoms). Drug-related adverse events were evaluated. @*Results@#According to the ITT analysis, the erosion improvement rates (posttreatment) in AD-203-treated and Mucosta Ⓡ -treated patients were 39.7% and 43.8%, respectively. According to the PP analysis, the erosion improvement rates (posttreatment) in AD-203-treated and Mucosta Ⓡ -treated patients were 39.3% and 43.7%, respectively. The one-sided 97.5% lower limit for the improvement rate difference between the study groups was −4.01% (95% confidence interval [CI], –13.09% to 5.06%) in the ITT analysis and −4.44% (95% CI, –13.65% to 4.78%) in the PP analysis. The groups did not significantly differ in the secondary endpoints in either analysis. Twenty-four AD-203-treated and 20 Mucosta Ⓡ -treated patients reported adverse events but no serious adverse drug reactions; both groups presented similar adverse event rates. @*Conclusions@#The new formulation of rebamipide 150 mg (AD-203) twice daily was not inferior to rebamipide 100 mg (Mucosta Ⓡ ) thrice daily. Both formulations showed a similar efficacy in treating erosive gastritis.
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Objective@#This study was conducted to identify the needs assessment for education and training of emergency medicine (EM) residents. @*Methods@#The results of a national survey of EM residents of the Korean Society of Emergency Medicine in 2019 were used. Education was one of the five categories in the survey. The preferred learning methods and their perceived importance and ability to perform in nine competencies were assessed. The Borich’s needs assessment model was used to analyze their needs. @*Results@#Among 591 EM residents, 382 responded, and 371 responses were finally analyzed. Regarding the learning methods, junior residents preferred in-hospital conferences, staff lectures, internet resources, and textbooks. Overall, medical knowledge and procedural skills were the most important, and research was less important to recognize. Medical knowledge showed the highest rank in the needs assessment in all years, and ethics and professionalism showed the lowest ranks. The needs for procedural skills were higher in junior years but lower in senior years. @*Conclusion@#These results will form the basis for the design of training programs to meet the educational needs of EM residents for each grade. Furthermore, an analysis of the educational needs should be done periodically according to the changes and demands of the times.
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Background@#Rotator cuff tears can be asymptomatic in some cases; however, even when the tear size is small, clinical symptoms can be very severe. This suggests that symptoms of rotator cuff tears are related to factors other than the size. Although synovitis has been cited as one of the factors, there is no grading system for synovitis in rotator cuff tears. Moreover, there are few studies that evaluated the relationship between synovitis and clinical features in patients with rotator cuff tears. @*Methods@#Patients with medium-sized rotator cuff tears, who were scheduled for arthroscopic repair, were recruited for this study.The glenohumeral joint was divided into 4 quarters. Then, vascularity and hypertrophy of the joint were graded in each quarter using a modified scoring system. Clinical assessment was performed preoperatively and at 3 months and 6 months after surgery.Finally, correlation between the severity of synovitis and clinical features was analyzed. @*Results@#The intraobserver correlation coefficient was 0.815 to 0.918 and the interobserver correlation coefficient was 0.779 to 0.992 for the single measurement. Vascularity was significantly correlated with the range of motion, strength, and constant score within 6 months after surgery. Hypertrophy was correlated with the range of motion within 6 months after surgery. @*Conclusions@#Synovitis in the shoulder with rotator cuff tears can be graded by using our modified scoring system. The severity of synovitis was closely related to the clinical features after surgery. Therefore, when treating patients with rotator cuff tears, treatment of synovitis should also be considered.
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Background/Aims@#S-isomer (S) pantoprazole is more bioavailable and less dependent on cytochrome 2C19 than is racemic pantoprazole. We aim to evaluate the efficacy and safety of 10 mg S-pantoprazole for treatment of non-erosive reflux disease (NERD). @*Methods@#In this phase 3, double-blind, randomized placebo controlled, multicenter study, 174 NERD patients were randomized to one of both treatment groups: 10 mg S-pantoprazole, or placebo once daily for 4 weeks. Symptoms and safety were assessed. The efficacy endpoints were complete relief of symptoms, > 50% improvement of all reflux symptoms and recurrence. @*Results@#Eighty-eight patients were assigned to the S-pantoprazole group (25 males, mean 43.7 years old) and 86 to the placebo group (32 males, mean 43.0 years old), and 163 patients were subjected to full Analysis Set. A higher proportion of patients in the S-pantoprazole group had complete symptom relief (42.0 % [34/81] vs 17.1% [14/82], P 50% symptom responses (66.0% vs 50.0%, P = 0.010 for heartburn; 64.2% vs 28.0%, P = 0.010 for acid regurgitation; and 51.9% vs 30.5%, P = 0.03 for epigastric discomfort) compared to the placebo group. The factors associated with poor responsiveness to PPI were older age, female, greater body mass index, and severe baseline symptoms. @*Conclusions@#Low dose of S-pantoprazole (10 mg) for 4 weeks was more efficacious than placebo in providing reflux symptom relief in patients with NERD, especially acid regurgitation. More doses or longer periods of treatment with S-pantoprazole would be needed to completely eliminate symptoms.
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Currently, the expanding recreational use of synthetic cannabinoids (SCBs) threatens public health. SCBs produce psychoactive effects similar to those of tetrahydrocannabinol, the main component of cannabis, and additionally induce unexpected pharmacological side effects. SCBs are falsely advertised as legal and safe, but in reality, SCB abuse has been reported to cause acute intoxication and addictive disorders. However, because of the lack of scientific evidence to elucidate their dangerous pharmacological effects, SCBs are weakly regulated and continue to circulate in illegal drug markets. In the present study, the intravenous self-administration (IVSA) paradigm was used to evaluate the abuse potential of three SCBs (AM-1248, CB-13, and PB-22) in rats. All three SCBs maintained IVSA with a large number of infusions and active lever presses, demonstrating their reinforcing effects.The increase of active lever presses was particularly significant during the early IVSA sessions, indicating the reinforcementenhancing effects of the SCBs (AM-1248 and CB-13). The number of inactive lever presses was significantly higher in the SCB groups (AM-1248 and CB-13) than that in the vehicle group, indicating their impulsive effects. In summary, these results demonstrated that SCBs have distinct pharmacological properties and abuse potential.
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Background/Aims@#S-isomer (S) pantoprazole is more bioavailable and less dependent on cytochrome 2C19 than is racemic pantoprazole. We aim to evaluate the efficacy and safety of 10 mg S-pantoprazole for treatment of non-erosive reflux disease (NERD). @*Methods@#In this phase 3, double-blind, randomized placebo controlled, multicenter study, 174 NERD patients were randomized to one of both treatment groups: 10 mg S-pantoprazole, or placebo once daily for 4 weeks. Symptoms and safety were assessed. The efficacy endpoints were complete relief of symptoms, > 50% improvement of all reflux symptoms and recurrence. @*Results@#Eighty-eight patients were assigned to the S-pantoprazole group (25 males, mean 43.7 years old) and 86 to the placebo group (32 males, mean 43.0 years old), and 163 patients were subjected to full Analysis Set. A higher proportion of patients in the S-pantoprazole group had complete symptom relief (42.0 % [34/81] vs 17.1% [14/82], P 50% symptom responses (66.0% vs 50.0%, P = 0.010 for heartburn; 64.2% vs 28.0%, P = 0.010 for acid regurgitation; and 51.9% vs 30.5%, P = 0.03 for epigastric discomfort) compared to the placebo group. The factors associated with poor responsiveness to PPI were older age, female, greater body mass index, and severe baseline symptoms. @*Conclusions@#Low dose of S-pantoprazole (10 mg) for 4 weeks was more efficacious than placebo in providing reflux symptom relief in patients with NERD, especially acid regurgitation. More doses or longer periods of treatment with S-pantoprazole would be needed to completely eliminate symptoms.
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Background and Objectives@#Fungus ball is the most common type of fungal sinusitis commonly associated with good prognosis. However, postoperative results depending on the extent of the lesion has not been investigated. This study aimed to identify differences in postoperative results depending on the location and extent of the fungus ball.Subjects and Method Medical records of 165 patients who underwent endoscopic sinus surgery and who were diagnosed with fungus balls by biopsy from 2010 to 2019 were retrospectively reviewed. Patients were classified into four grades according to the location and extent of the fungus ball based on their endoscopic and CT findings. Poor outcome is defined as any pathologic signs such as nasal secretion, granulation, and polyps or narrowing of the natural ostium observed postoperatively according to Kennedy’s criteria, whereas good outcome is defined as absence of pathologic signs. @*Results@#A total of 23 patients were Grade 1, 38 Grade 2, 67 Grade 3, and 37 Grade 4. Grades 1 and 2 were mostly asymptomatic. However, as the location of the fungus ball became closer to the natural ostium, patients complained postnasal drip and purulent discharge. Grades 3 and 4, who have much severe and more extensive lesions than those of Grades 1 and 2, had poor outcome (p=0.007) and took longer time to completely recover (p<0.001). @*Conclusion@#Wound healing was delayed and poor when the fungus ball was located closer to the natural ostium of the maxillary sinus. Therefore, preoperative consultation using endoscopic and CT findings could be useful for predicting their postoperative results.
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Recently, real-time polymerase chain reaction (PCR) using the U-TOP™HL Genotyping Kit has been introduced to detect genetic hearing loss caused by certain type of gene variants popularly found in Korea. The mitochondrial 12S ribosomal ribonucleic acid (rRNA) genes are related to aminoglycoside induced or non-syndromic, sensorineural hearing loss. Among them, 1555A>G is commonly found and reported worldwide. We are presenting the case of a mother and a son, who were screened by real-time PCR using the U-TOP™HL Genotyping Kit and were found both to have the mitochondrial 12s rRNA 1555A>G variant with a different hearing loss phenotype. This report encourages clinicians to use this or similar screen methods for patients with familial hearing loss.
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Purpose@#Endocrine therapy is the first-line treatment recommended for patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer without visceral crisis. However, this recommendation has not been followed clinically because of efficacy issues. In this study, the survival of patients with HR-positive/HER2-negative metastatic breast cancer was evaluated based on the following first-line treatment regimens: the combination of palbociclib plus letrozole, conventional endocrine therapy, or chemotherapy. @*Methods@#Medical records were reviewed for this retrospective analysis. Patients with HR-positive/HER2-negative metastatic breast cancer were included. Progression-free survival (PFS) and overall survival (OS) were compared based on first-line treatment regimens. @*Results@#A total of 184 patients were included in the analysis. The first-line treatments were palbociclib plus letrozole in 46 patients (25.0%), endocrine therapy in 40 patients (21.7%), and chemotherapy in 98 patients (53.3%). The PFS of the palbociclib plus letrozole group was significantly longer than that of the endocrine therapy (hazard ratio=3.43, p<0.001) and chemotherapy (hazard ratio=2.88, p=0.001) groups. No significant difference was observed between the endocrine therapy and chemotherapy groups (p=0.430). The OS of the palbociclib plus letrozole group was significantly longer than that of the endocrine therapy (hazard ratio=5.34, p=0.009) and chemotherapy (hazard ratio 4.23, p=0.043) groups. No significant difference was observed between the endocrine therapy and chemotherapy groups (p=0.451). @*Conclusion@#The combination regimen of palbociclib and letrozole could be recommended as the first-line treatment of choice in patients with HR-positive/HER2-negative metastatic breast cancer.