Purpose: Infertility affects 10% to 15% of couples, and male factor accounts for 50% of the cases. The relevant male genetic factors, which account for at least 15% of male infertility, include Y-chromosome microdeletions. We investigated clinical data and patterns of Y-chromosome microdeletions in Korean infertile men. Materials and Methods: A total of 919 infertile men whose sperm concentration was ≤5 million/mL in two consecutive analyses were investigated for Y-chromosome microdeletion. Among them, 130 infertile men (14.1%) demonstrated Y-chromosome microdeletions. Medical records were retrospectively reviewed. Results: In 130 men with Y-chromosome microdeletions, 90 (69.2%) had azoospermia and 40 (30.8%) had severe oligozoospermia.The most frequent microdeletions were in the azoospermia factor (AZF) c region (77/130, 59.2%), followed by the AZFb+c (30/130, 23.1%), AZFa (8/130, 6.2%), AZFb (7/130, 5.4%), AZFa+b+c (7/130, 5.4%), and AZFa+c (1/130, 0.7%) regions. In men with oligozoospermia, 37 (92.5%) had AZFc microdeletion. Chromosomal abnormalities were detected in 30 patients (23.1%). Higher follicle-stimulating hormone level (23.2±13.5 IU/L vs. 15.1±9.0 IU/L, p<0.001), higher luteinizing hormone level (9.7±4.6 IU/L vs. 6.0±2.2 IU/L, p<0.001), and lower testis volume (10.6±4.8 mL vs. 13.3±3.8 mL, p<0.001) were observed in azoospermia patients compared to severe oligozoospermia patients. Conclusions Y-chromosome microdeletion is a common genetic cause of male infertility. Therefore, Y-chromosome microdeletion test is recommended for the accurate diagnosis of men with azoospermia or severe oligozoospermia. Appropriate genet

Background: s/Aims: Reported incidence of extrahepatic bile duct cancer is higher in Asians than in Western populations. Korea, in particular, is one of the countries with the highest incidence rates of extrahepatic bile duct cancer in the world. Although research and innovative therapeutic modalities for extrahepatic bile duct cancer are emerging, clinical guidelines are currently unavailable in Korea. The Korean Society of Hepato-Biliary-Pancreatic Surgery in collaboration with related societies (Korean Pancreatic and Biliary Surgery Society, Korean Society of Abdominal Radiology, Korean Society of Medical Oncology, Korean Society of Radiation Oncology, Korean Society of Pathologists, and Korean Society of Nuclear Medicine) decided to establish clinical guideline for extrahepatic bile duct cancer in June 2021. Methods: Contents of the guidelines were developed through subgroup meetings for each key question and a preliminary draft was finalized through a Clinical Guidelines Committee workshop. Results: In November 2021, the finalized draft was presented for public scrutiny during a formal hearing. Conclusions The extrahepatic guideline committee believed that this guideline could be helpful in the treatment of patients.

Background/Aims: Synchronous multiple gastric cancer (SMGC) accounts for approximately 6% to 14% of gastric cancer (GC) cases. This study aimed to identify risk factors for SMGC. Methods: A total of 14,603 patients diagnosed with GC were prospectively enrolled. Data including age, sex, body mass index, smoking, alcohol consumption, family history, p53 expression, microsatellite instability, cancer classification, lymph node metastasis, and treatment were collected. Risk factors were analyzed using logistic regression analysis between a single GC and SMGC. Results: The incidence of SMGC was 4.04%, and that of early GC (EGC) and advanced GC (AGC) was 5.43% and 3.11%, respectively. Patients with SMGC were older (65.33 years vs 61.75 years, p<0.001) and more likely to be male. Lymph node metastasis was found in 27% of patients with SMGC and 32% of patients with single GC. Multivariate analysis showed that SMGC was associated with sex (male odds ratio [OR], 1.669; 95% confidence interval [CI], 1.223 to 2.278; p=0.001), age (≥65 years OR, 1.532; 95% CI, 1.169 to 2.008; p=0.002), and EGC (OR, 1.929; 95% CI, 1.432 to 2.600; p<0.001). Survival rates were affected by Lauren classification, sex, tumor size, cancer type, distant metastasis, and venous invasion but were not related to the number of GCs. However, the survival rate of AGC with SMGC was very high. Conclusions SMGC had unique characteristics such as male sex, older age, and EGC, and the survival rate of AGC, in which the intestinal type was much more frequent, was very good (Trial registration number: NCT04973631).

Background: The objective of this study was to evaluate the efficacy and safety of totally thoracoscopic ablation (TTA) in patients with recurrent atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA). Methods: From February 2012 to May 2020, 460 patients who underwent TTA were classified into two groups: CA (presence of RFCA history, n = 74) and nCA groups (absence of RFCA history, n = 386). Inverse probability of treatment weighting (IPTW) analyses were used to adjust for confounders. The primary endpoint was freedom from the composite of AF, typical atrial flutter, atypical atrial flutter and any atrial tachyarrhythmia, lasting more than 30 seconds during the follow-up. All patients were followed up at 3, 6, and 12 months via electrocardiogram and 24-hour Holter monitoring. Results: Bilateral pulmonary vein isolation (PVI) was conducted in all patients and the conduction block tests were confirmed. In the CA group, difficult PVI occasionally occurred due to structural changes, such as pericardial adhesion and fibrosis of the pulmonary venous structure, caused by a previous catheter ablation. Early complications such as stroke and pacemaker insertion were not different between the two groups. The normal sinus rhythm was maintained in 70.1% (317/460) patients after a median follow-up period of 38.1 months.The IPTW-weighted Kaplan-Meier curves revealed that freedom from AF events at 5 years was 68.4% (95% confidence interval, 62.8–74.5) in the nCA group and 31.2% (95% confidence interval, 16.9–57.5) in the CA group (P < 0.001). In IPTW-weighted Cox regression, preoperative left atrial diameter, persistent or long-standing AF, the presence of congestive heart failure and catheter ablation history were associated with AF events. Conclusion Patients in the CA group showed a higher recurrence rate of AF than those in the nCA group, while TTA was safely performed in both the groups.

Background/Aims: There are few reports regarding mixed carcinoma, defined as a mixture of glandular and poorly cohesive components, in patients with gastric cancer (GC). The aim of this study was to evaluate the proportion and characteristics of mixed carcinoma in GC patients. Methods: A total of 7,215 patients diagnosed with GC at Seoul National University Bundang Hospital were enrolled from March 2011 to February 2020. GC was divided into four groups (wellmoderately differentiated GC, poorly differentiated GC, poorly cohesive carcinoma, and mixed carcinoma). The proportion of each GC type and the clinicopathological features were analyzed and divided into early GC and advanced GC. Results: The proportion of mixed carcinoma was 10.9% (n=787). In early GC, submucosal invasion was the most common in poorly differentiated (53.7%), and mixed carcinoma ranked second (41.1%). Mixed carcinoma showed the highest proportion of lymph node metastasis in early GC (23.0%) and advanced GC (78.3%). In advanced GC, the rate of distant metastasis was 3.6% and 3.9% in well-moderately differentiated GC and mixed carcinoma, respectively, lower than that in poorly differentiated GC (6.4%) and poorly cohesive carcinoma (5.7%), without statistical significance. Conclusions Mixed carcinoma was associated with lymph node metastasis compared to other histological GC subtypes. And it showed relatively common submucosal invasion in early GC, but the rates of venous invasion and distant metastasis were lower in advanced GC. Further research is needed to uncover the mechanism underlying these characteristics of mixed carcinoma (Trial registration number: NCT04973631).

Background/Aims: The incidence and prognosis of gastric cancer (GC) shows sex difference.This study aimed to evaluate the effect of body mass index (BMI) on GC survival depending on sex. Methods: The sex, age, location, histology, TNM stages, BMI, and survival were analyzed in GC patients from May 2003 to February 2020 at the Seoul National University Bundang Hospital. Results: Among 14,688 patients, there were twice as many males (66.6%) as females (33.4%).However, under age 40 years, females (8.6%) were more prevalent than males (3.1%). Cardia GC in males showed a U-shaped distribution for underweight (9.6%), normal (6.4%), overweight (6.1%), obesity (5.6%), and severe obesity (9.3%) but not in females (p=0.003). Females showed decreased proportion of diffuse-type GC regarding BMI (underweight [59.9%], normal [56.8%], overweight [49.5%], obesity [44.8%], and severe obesity [41.7%]), but males did not (p<0.001). Both sexes had the worst prognosis in the underweight group (p<0.001), and the higher BMI, the better prognosis in males, but not females. Sex differences in prognosis according to BMI tended to be more prominent in males than in females in subgroup analysis of TNM stages I, II, and III and the operative treatment group. Conclusions GC-specific survival was affected by BMI in a sex-dependent manner. These differences may be related to genetic, and environmental, hormonal factors; body composition; and muscle mass (Trial registration number: NCT04973631).

Purpose: This systematic review and meta-analysis investigated the sperm retrieval rate (SRR) and pregnancy rate after testicular sperm extraction in men with azoospermia and those with a history of cryptorchidism treated by orchiopexy. Materials and Methods: The SRR and clinical pregnancy rate were investigated. We performed a sub-analysis that included factors such as bilaterality, age, and idiopathic non-obstructive azoospermia (iNOA). The analysis comprised 13 studies from January 1995 to July 2021. The data sources were PubMed/MEDLINE, Embase, and the Cochrane Library included “cryptorchidism”, “orchidopexy”, “azoospermia”, and “testicular sperm extraction”. Results: The overall mean SRR was 63.3% (95% confidence interval [CI], 57.6%–68.6%; I2 =62.4%), and the overall mean clinical pregnancy rate was 30.1% (95% CI, 22.6%–38.8%; I2 =69.9%). The meta-analysis comparing the SRR, there was no significant difference between patients with a history of bilateral and unilateral orchiopexy (relative risk [RR]=1.02; 95% CI, 0.89–1.16; p=0.79). Orchiopexy performed under the age of 10 years showed significantly increased SRR compared to the age of over 10 years (RR=1.25; 95% CI, 1.06–1.47; p=0.008). Azoospermic men with a history of cryptorchidism treated by orchiopexy had significantly higher SRR than iNOA (RR=1.90; 95% CI, 1.40–2.58; p<0.0001). Conclusions Men with azoospermia and a history of cryptorchidism treated by orchiopexy had significantly higher SRR than those with iNOA after testicular sperm extraction. Furthermore, patients who underwent orchiopexy before the age of ten years had significantly higher SRR than patients operated at an older than the age of ten years.

Background: and Purpose We aimed to develop a model predicting early recanalization after intravenous tissue plasminogen activator (t-PA) treatment in large-vessel occlusion. Methods: Using data from two different multicenter prospective cohorts, we determined the factors associated with early recanalization immediately after t-PA in stroke patients with large-vessel occlusion, and developed and validated a prediction model for early recanalization. Clot volume was semiautomatically measured on thin-section computed tomography using software, and the degree of collaterals was determined using the Tan score. Follow-up angiographic studies were performed immediately after t-PA treatment to assess early recanalization. Results: Early recanalization, assessed 61.0±44.7 minutes after t-PA bolus, was achieved in 15.5% (15/97) in the derivation cohort and in 10.5% (8/76) in the validation cohort. Clot volume (odds ratio [OR], 0.979; 95% confidence interval [CI], 0.961 to 0.997; P=0.020) and good collaterals (OR, 6.129; 95% CI, 1.592 to 23.594; P=0.008) were significant factors associated with early recanalization. The area under the curve (AUC) of the model including clot volume was 0.819 (95% CI, 0.720 to 0.917) and 0.842 (95% CI, 0.746 to 0.938) in the derivation and validation cohorts, respectively. The AUC improved when good collaterals were added (derivation cohort: AUC, 0.876; 95% CI, 0.802 to 0.950; P=0.164; validation cohort: AUC, 0.949; 95% CI, 0.886 to 1.000; P=0.036). The integrated discrimination improvement also showed significantly improved prediction (0.097; 95% CI, 0.009 to 0.185; P=0.032). Conclusions The model using clot volume and collaterals predicted early recanalization after intravenous t-PA and had a high performance. This model may aid in determining the recanalization treatment strategy in stroke patients with large-vessel occlusion.

Background: As a laboratory animal resource, the ICR mouse is commonly used in a variety of research fields. However, information on differences in exercise-related characteristics in ICR mice derived from different lineages and the underlying mechanisms remains to be elucidated. In this study, we investigated the intrinsic exercise capacity and a magnitude of response to acute exercise, and sought to identify mechanisms contributing to difference in Korl:ICR (a novel ICR lineage recently established by the National Institute of Food and Drug Safety Evaluation, Korea) and two commercialized ICR lineages derived from different origins (viz., A:ICR mouse from Orient Bio Com, the United States, and B:ICR mouse from Japan SLC Inc., Japan). Results: Results showed that despite no significant difference in body weight and weight-proportioned tissue mass of heart and skeletal muscles among groups, the relatively low intrinsic exercise capacity and exaggerated response to acute exercise were identified in B:ICR comparted with Korl:ICR and A:ICR, as reflected by total work and lactate threshold (LT). Also, the mitochondrial efficiency expressed as the complex 1 and complex 1 + 2 respiratory control ratio (RCR) values for cardiac mitochondrial O 2 consumption in B:ICR was significantly lower than that in Korl:ICR with higher level of state 2 respiration by glutamate/malate and UCP3 expression in cardiac muscle. Conclusions Taken together, these results indicate that the intrinsic exercise capacity of ICR mouse varies according to lineages, suggesting the role of cardiac mitochondrial coupling efficiency as a possible mechanism that might contribute to differences in the intrinsic exercise capacity and magnitude of response to exercise.

Background: and Purpose We aimed to develop a model predicting early recanalization after intravenous tissue plasminogen activator (t-PA) treatment in large-vessel occlusion. Methods: Using data from two different multicenter prospective cohorts, we determined the factors associated with early recanalization immediately after t-PA in stroke patients with large-vessel occlusion, and developed and validated a prediction model for early recanalization. Clot volume was semiautomatically measured on thin-section computed tomography using software, and the degree of collaterals was determined using the Tan score. Follow-up angiographic studies were performed immediately after t-PA treatment to assess early recanalization. Results: Early recanalization, assessed 61.0±44.7 minutes after t-PA bolus, was achieved in 15.5% (15/97) in the derivation cohort and in 10.5% (8/76) in the validation cohort. Clot volume (odds ratio [OR], 0.979; 95% confidence interval [CI], 0.961 to 0.997; P=0.020) and good collaterals (OR, 6.129; 95% CI, 1.592 to 23.594; P=0.008) were significant factors associated with early recanalization. The area under the curve (AUC) of the model including clot volume was 0.819 (95% CI, 0.720 to 0.917) and 0.842 (95% CI, 0.746 to 0.938) in the derivation and validation cohorts, respectively. The AUC improved when good collaterals were added (derivation cohort: AUC, 0.876; 95% CI, 0.802 to 0.950; P=0.164; validation cohort: AUC, 0.949; 95% CI, 0.886 to 1.000; P=0.036). The integrated discrimination improvement also showed significantly improved prediction (0.097; 95% CI, 0.009 to 0.185; P=0.032). Conclusions The model using clot volume and collaterals predicted early recanalization after intravenous t-PA and had a high performance. This model may aid in determining the recanalization treatment strategy in stroke patients with large-vessel occlusion.