1.Accuracy of Two Direct Antibiotic-Susceptibility Tests and Their Impact on the Optimal Treatment of Enterobacterales-Associated Bloodstream Infection:Comparison of the QMAC-dRAST V2.5 and BD Phoenix M50 Systems
Ji Sang YOON ; Joo An KWON ; Jeong Seob SHIN ; Hyun Soo SEOK ; In Young YOO ; Yeon-Joon PARK
Annals of Laboratory Medicine 2026;46(3):279-288
Background:
Rapid pathogen identification and antibiotic-susceptibility tests (ASTs) are important for treating bloodstream infections. We compared the performance of the QMAC-dRAST and BD Phoenix M50 direct AST (dPhoenix) systems using bacterial pellets prepared from positive blood culture broth and evaluated their impact on treatment modification.
Methods:
Direct AST results for 106 Enterobacterales isolates were retrospectively reviewed. Conventional broth microdilution was used to calculate categorical agreement (CA), very major error (VME), major error (ME), and minor error (mE). For isolates showing high VMEs in both methods, supplementary tests were performed. Clinical impact was evaluated by calculating the time required to obtain AST results (time-to-result) and observing changes in antibiotics prescribed after performing ASTs.
Results:
Both systems showed acceptable overall CA, VME, ME, and mE values (QMACdRAST: 93.6%, 1.6%, 0.9%, and 5.3%, respectively; dPhoenix: 93.1%, 0.9%, 0.6%, and 6.2%, respectively). Piperacillin–tazobactam showed high VMEs with QMAC-dRAST (4/20, 20.0%) and dPhoenix (3/20, 15.0%). Colony AST on 13 isolates revealed that QMACdRAST testing yielded lower minimal inhibitory concentrations (MICs) for piperacillin–tazobactam with three isolates, whereas dPhoenix testing yielded higher MICs with two isolates and lower MICs with two isolates. The average time-to-result was 20.8 hr and 30.1 hr for QMAC-dRAST and dPhoenix, respectively (P < 0.001). After AST, the number of optimal treatments increased from 43 (46.7%) to 72 (78.3%) (P < 0.001).
Conclusions
The QMAC-dRAST and dPhoenix systems provided reliable AST results with a short time-to-result. However, we recommend performing complementary tests, such as the disk diffusion test, for piperacillin–tazobactam.
2.Changes in Esophageal Transit Scintigraphy After Peroral Endoscopic Myotomy in Patients With Achalasia
Young Hoon YOUN ; Kyung Soo KIM ; Yeon Jin JE ; Jae-Hoon LEE ; Young Hoon RYU ; Hyojin PARK
Journal of Neurogastroenterology and Motility 2026;32(1):30-34
Background/Aims:
Esophageal transit scintigraphy is a non-invasive nuclear medicine imaging modality for people with esophageal transit problems. In particular, changes in esophageal motor function can be evaluated non-invasively before and after the treatment in patients undergoing peroral endoscopic myotomy (POEM) for achalasia. This study compared the changes in several parameters of esophageal transit and manometry in patients with achalasia who underwent POEM.
Methods:
This study retrospectively analyzed prospectively collected data from POEM participants. We included 38 patients with achalasia who underwent high-resolution manometry and esophageal transit scintigraphy before POEM and after POEM from 2016 to 2023.
Results:
All patients had clinical treatment successfully (Eckardt score < 3). Lower esophageal sphincter (LES) pressures were significantly reduced after POEM, including basal resting LES pressure and integrated relaxation pressure (P < 0.001).Esophageal emptying, as assessed by the residual fraction of retained radioactivity at 10 seconds after isotope ingestion, improved from 54.3% to 27.3% (P < 0.001). Analysis of the change in time-to-peak on the time-radioactivity curve showed that it shortened significantly in the upper and middle portions of the esophagus (P < 0.05) but not in the lower portion.The Eckardt symptom score significantly correlated with pre-POEM integrated relaxation pressure (P < 0.05). Post-POEM, the symptom score significantly correlated with time-to-peak of the upper portion of the esophagus (P < 0.05).
Conclusions
Patients with achalasia who received POEM showed improved not only manometric LES parameters but also esophageal transit. Analysis of the radiation curve’s time-to-peak showed that improved retention in the upper portion is an indicator of symptoms improvement in patients who underwent POEM.
3.Radiologic Response Assessment With RECIST 1.1 and mRECIST in Patients With Hepatocellular Carcinoma Treated With Atezolizumab Plus Bevacizumab
Boryeong JEONG ; Hyo Jung PARK ; Won-Mook CHOI ; Sang Hyun CHOI ; Kyung Won KIM ; So Yeon KIM ; Seung Soo LEE
Korean Journal of Radiology 2026;27(5):428-439
Objective:
Evidence remains limited regarding whether Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) or modified RECIST (mRECIST) more reliably assesses treatment response in patients with hepatocellular carcinoma (HCC) receiving atezolizumab plus bevacizumab (Atezo/Bev). This study aimed to evaluate response patterns based on RECIST 1.1 and mRECIST, analyze inter-reader agreement, and assess their prognostic value for overall survival (OS) in patients with HCC receiving first-line Atezo/Bev.
Materials and Methods:
This retrospective study included patients with HCC treated with first-line Atezo/Bev between June 2020 and December 2022 at a tertiary center. Patients with at least one hypervascular hepatic target lesion were eligible. Two radiologists independently assessed treatment responses using RECIST 1.1 and mRECIST. Inter-reader agreement was evaluated using Cohen’s kappa coefficient. Time-dependent Cox regression analysis was performed, with radiologic response and progression treated as time-varying covariates. Prognostic discrimination was evaluated using Harrell’s concordance index (C-index).
Results:
A total of 207 patients were included (171 men; median age, 63 years; median follow-up, 10.7 months [range, 0.8– 46.4 months]; median OS, 10.7 months [95% confidence interval, 9.2–12.8 months]). mRECIST identified more responders than RECIST 1.1 (54.6% vs. 16.9%). RECIST 1.1 demonstrated excellent inter-reader agreement, whereas mRECIST showed substantial agreement (weighted kappa, 0.89 vs. 0.79). A significantly higher rate of dissociated responses was observed with mRECIST than with RECIST 1.1 (14.0% vs. 4.3%, P < 0.001). Both RECIST 1.1- and mRECIST-based responses and progression were independently associated with OS. Models incorporating RECIST 1.1 demonstrated slightly higher C-index values than those incorporating mRECIST (RECIST 1.1: 0.68 for response and 0.75 for progression; mRECIST: 0.65 and 0.70, respectively).
Conclusion
RECIST 1.1 is more reproducible and prognostically valuable for guiding treatment decisions in patients with HCC receiving first-line Atezo/Bev. However, this does not invalidate the use of mRECIST as a biological tumor response marker.
4.DNA Damage and Nuclear Anaplasia Induced by Trastuzumab Deruxtecan in Cancer Cells with Variable HER2 Expression and Homologous Recombination Deficiency Status
So Hyeon KIM ; Yoonjung PARK ; Ahrum MIN ; Hye Yeon PARK ; Yu-Jin KIM ; Sujin HAM ; Jiwon KOH ; Seongyeong KIM ; Dae-Won LEE ; Han Suk RYU ; Jin-Soo KIM ; Kyung-Hun LEE ; Seock-Ah IM
Cancer Research and Treatment 2026;58(2):407-422
Purpose:
Human epidermal growth factor receptor 2 (HER2) is amplified or overexpressed in various malignancies, including breast and gastric cancers, and is associated with poor prognosis. Although HER2-targeted therapies, such as trastuzumab, improve outcomes in HER2-positive tumors, resistance often develops, and HER2-low tumors remain largely untargeted. Trastuzumab deruxtecan (T-DXd; DS-8201a) is a HER2-targeted antibody-drug conjugate with potent activity in HER2-positive and HER2-low tumors. This study evaluates its antitumor mechanisms and efficacy in HER2-positive, HER2-low, and homologous recombination deficiency (HRD)–associated models.
Materials and Methods:
Effects of T-DXd were assessed in cancer cell lines with diverse HER2 expression and HRD status. In vivo efficacy was evaluated using a xenograft model derived from HER2-low SNU-601 gastric cancer cells.
Results:
T-DXd reduced HER2 phosphorylation and downstream signaling (AKT, ERK) in HER2-positive cells. It induced DNA damage accumulation, as evidenced by increased γH2AX and p-Chk1 expression, and triggered apoptosis through cleaved poly(ADP-ribose) polymerase and caspase-3 activation, confirmed by annexin V staining. Similar effects were observed in HER2-low cells, with greater sensitivity in HRD cells. In xenografts, T-DXd reduced tumor volume by up to 80% at 4 mg/kg and 10 mg/kg. Histological analyses showed decreased Ki-67 and increased apoptosis. Furthermore, T-DXd induced G2/M cell cycle arrest and nuclear anaplasia, suggesting disruption of chromosomal stability as a potential antitumor mechanism. No significant toxicity, including body weight loss, was observed.
Conclusion
These findings highlight T-DXd’s effectiveness in HER2-low and HRD tumors, supporting its broader clinical application, including strategies targeting DNA damage repair pathways.
5.Pilot Study for Feasibility of Onco-Geriatric Intervention Model in Older Patients with Cancer in a Tertiary Academic Hospital
Jin Won KIM ; Jung-Yeon CHOI ; Woochan PARK ; Minsu KANG ; Jeongmin SEO ; Eun Hee JUNG ; Koung Jin SUH ; Ji-Won KIM ; Se Hyun KIM ; Yu Jung KIM ; Keun-Wook LEE ; Sang-A KIM ; Ji Yun LEE ; Jeong-Ok LEE ; Soo-Mee BANG ; Kwang-il KIM ; Jee Hyun KIM
Cancer Research and Treatment 2026;58(1):329-338
Purpose:
Older cancer patients face unique challenges due to age-related physiological changes, increasing their vulnerability to treatment-related toxicities. Geriatric assessment (GA) is a validated tool for optimizing care, yet there is no consensus on integrating geriatric interventions into oncology. This study evaluates the feasibility of a tailored onco-geriatric intervention model incorporating the KG-7 screening tool.
Materials and Methods:
This prospective study included 30 patients aged ≥ 70 years with solid tumors undergoing adjuvant or palliative chemotherapy. Patients scoring ≤ 5 of KG-7 were eligible. Tailored interventions incorporating KG-7 included polypharmacy, functional status, mobility, nutrition, cognition, emotional well-being, insomnia, social support, and medical problem. KG-7, GA, and quality of life (QoL) were followed at 12 weeks.
Results:
Participants (median age, 79.5 years) had colon (43.3%), pancreatic (23.3%), or gastric cancer (23.3%). At baseline, most patients showed independent activities of daily living (100%)/instrumental activities of daily living (90%). However, 93.3% had abnormal GA. Particularly, 86.7% were either malnourished or at risk of malnutrition. The most frequently identified intervention needs included polypharmacy (70.0%), nutritional support (60.0%), and emotional well-being (50.0%) with high adherence (100.0%, 88.9%, and 46.7%, respectively). At 12 weeks, KG-7 scores improved in 43.8% of patients, and 69.2% of GA domains were improved. QoL analysis revealed modest improvement in Global Health Status (mean difference, 6.3; p=0.176). One-year survival rates were 92.3% and 79.4% for adjuvant and palliative groups, respectively.
Conclusion
The onco-geriatric intervention model incorporating KG-7 demonstrated high feasibility and potential to enhance clinical outcomes. Future studies should validate this approach in randomized trials to optimize care for older cancer patients.
6.Guidelines for the Management of Adult Subglottic and Tracheal Stenosis From the Korean Bronchoesophagological Society
Jung-Hae CHO ; Gene HUH ; Jae-Keun CHO ; Jae Won CHANG ; Jun-Ook PARK ; Young Chan LEE ; Jae Hyun JEON ; Jeon Yeob JANG ; Byeong-Ho JEONG ; Yeon Soo KIM ; Inn-Chul NAM ; Gil Joon LEE ; Woo Sik YU ; Heejin KIM ; Minhyung LEE ; Ji Won KIM ; Seung Hoon WOO ; Il-Seok PARK ; Jin Pyeong KIM ;
Clinical and Experimental Otorhinolaryngology 2026;19(1):1-20
Subglottic stenosis (SGS) and tracheal stenosis (TS) are rare conditions that can cause significant breathing difficulties and, if not properly managed, may lead to life-threatening complications. Despite their clinical importance, debate continues regarding the optimal management of adult SGS and TS, and no comprehensive guidelines have been established to date. The Korean Bronchoesophagological Society appointed a task force to develop clinical practice guidelines with the goal of providing evidence-based recommendations for managing SGS and TS in adults. The task force conducted a systematic review of the relevant literature by searching PubMed, Embase, and the Cochrane Library using predefined search terms aligned with key clinical questions. The quality of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach, which also informed the formulation and reporting of the recommendations. The strength of each recommendation reflects the guideline panel’s confidence that the benefits of an intervention outweigh its risks for eligible patients. After drafting the guidelines, feedback was obtained through Delphi questionnaires completed by members of the Korean Bronchoesophagological Society. Ultimately, the committee developed 17 evidence-based recommendations across four categories: initial evaluation, medical management, surgical treatment, and postoperative management and rehabilitation. These guidelines aim to support clinicians in delivering optimal care to adult patients with SGS and TS.
7.Clinical Application of Pharmacogenomics in Stroke Management: Current Evidence and Future Directions
Keon-Joo LEE ; Minkyung KANG ; Eung Joon LEE ; Jaeseong OH ; Na-Young HAN ; Jeong-Yoon LEE ; Joo-Yeon LEE ; Soo Ji LEE ; Stéphanie DEBETTE ; Guillaume PARÉ ; Daniel WOO ; Andrew ELDEIRY ; Young Seo KIM ; Jinkwon KIM ; Jong-Moo PARK ; Juneyoung LEE ; Joohon SUNG ; Jay Chol CHOI ; Hee-Joon BAE
Journal of Stroke 2026;28(1):58-75
Pharmacogenomic variations may significantly influence responses to commonly prescribed stroke medications. Despite accumulating evidence, genetic testing has not yet been widely integrated into stroke care. This review summarizes current evidence and provides practical guidance for clinical implementation. Pharmacogenomic studies and clinical guidelines related to antiplatelet agents, anticoagulants, and statins were reviewed, with particular emphasis on East Asian populations. Substantial evidence supports genotype-guided use of clopidogrel (CYP2C19), warfarin (CYP2C9, VKORC1, CYP4F2), and statins (SLCO1B1, ABCG2). For aspirin, PTGS1/2 and PEAR1 variants have been investigated; however, current data remain insufficient for clinical application. Regarding direct oral anticoagulants (DOACs), candidate genes such as ABCB1 and CES1 demonstrate pharmacokinetic associations, though robust clinical outcome data are lacking. Distinct allele frequencies in East Asians—such as higher prevalence of CYP2C19 and ABCG2 variants—underscore the need for population-specific strategies. Beyond single-gene approaches, polygenic risk scores, pharmacogenomic panels, and integration with multi-omics data and artificial intelligence represent promising directions for personalized therapy. Pharmacogenomic testing can enhance stroke pharmacotherapy, particularly in populations with high frequencies of actionable variants. Broader implementation requires rapid testing platforms, clinician education, tailored clinical guidelines, and real-world validation of aspirin, DOACs, and multi-gene approaches. Future research should expand population-specific studies and integrate pharmacogenomics within the broader framework of precision medicine to ensure equitable clinical benefit.
8.Low vitamin C concentrations and prognosis in critically ill children
Min Jung KIM ; Yoon Hee KIM ; Soo Yeon KIM ; Jong Deok KIM ; Mireu PARK ; Hamin KIM ; Myung Hyun SOHN ; Kyung Won KIM
Acute and Critical Care 2025;40(3):482-490
The administration of high-dose vitamins has been focused on in critically ill patients as adjunctive therapy for life-threatening conditions. We evaluated the association between serum vitamin C concentrations and patient prognosis. Methods: We retrospectively reviewed and collected clinical and biochemical data, including thiamine and vitamin C levels, of patients admitted to the pediatric intensive care unit (PICU). Results: In total, 177 patients were admitted to the PICU during the study period, and 63 children were enrolled in this study. The most common reason for PICU admission was sepsis (33.3%). The median thiamine and vitamin C levels were 3.6 µg/dl (interquartile range [IQR], 2.9–4.5 µg/dl) and 2.84 µg/ml (IQR, 1.61–4.55 µg/ml), respectively. Thiamine deficiency was observed in 10 patients (15.9%), and 17 (27.0%) had vitamin C deficiency. There were no differences in the vitamin levels according to the reason for PICU admission. Vitamin C levels were affected by nutritional status. The length of stay in the PICU and duration of mechanical ventilation were longer in patients with vitamin C deficiency than in those without (P=0.035 and P=0.010, respectively). The serum delta neutrophil index and C-reactive protein and lactate levels increased in the vitamin C-deficient group (P=0.028 and P=0.039, respectively). There was a significant difference in Pediatric Index of Mortality 3 scores according to vitamin C levels but not in mortality directly. Conclusions: Vitamin C deficiency was associated with elevated inflammatory marker levels, increased mechanical ventilation durations, and PICU admission. Our results support the potential benefits of vitamin C administration in critically ill children.
9.Clinical Implications of Circulating Tumor DNA in Multiple Myeloma and Its Precursor Diseases
Sung-Soo PARK ; Na Yung KIM ; Ji-Young LIM ; Jung Yeon LEE ; Sujin YUN ; Yeun-Jun CHUNG ; Seung-Hyun JUNG ; Chang-Ki MIN
Annals of Laboratory Medicine 2025;45(3):279-290
Background:
Genetic alterations play a pivotal role in multiple myeloma (MM) development and therapeutic resistance. Traditionally, the genetic profiling of MM requires invasive bone marrow (BM) procedures; however, these procedures are associated with patient discomfort and cannot fully capture the spatial and temporal heterogeneity of the disease.Therefore, we investigated the clinical implications of liquid biopsy using targeted deep sequencing.
Methods:
We analyzed the genetic profiles of circulating tumor DNA (ctDNA) by targeted deep sequencing from 102 patients, including those with monoclonal gammopathy of undetermined significance (MGUS, N = 7), smoldering MM (N = 6), and symptomatic MM (N = 89).
Results:
The number of ctDNA mutations increased with disease progression from MGUS to MM, with averages of 1.0 mutations in MGUS, 1.8 mutations in smoldering MM, and 1.9 mutations in MM, respectively. Shared mutations between BM and ctDNA were more prevalent in MM (68.9%) than in MGUS (25.0%). RAS/RAF and TP53 mutations were significantly enriched in MM ctDNA. Specific mutations were associated with clinical features in patients with MM: hypercalcemia and TET2 (P = 0.006), renal insufficiency and NRAS (P = 0.012), paramedullary myeloma and TP53(P = 0.02), and extramedullary myeloma and NRAS (P = 0.007). TET2 mutations significantly affected 2-yr progression-free survival (hazard ratio = 7.11, P = 0.003). Serial ctDNA profiling accurately predicted treatment response in patients with MM.
Conclusions
Our findings highlight the potential of liquid biopsy for understanding MM progression and prognosis utilizing a minimally invasive approach, paving the way for its integration into personalized treatment strategies and real-time disease monitoring.
10.Microbiological and clinical characteristics of vulvovaginitis in premenarcheal and postmenarcheal girls in a tertiary center in South Korea
Soo Jin PARK ; Ki Wook YUN ; Ji Yeon HAN ; Sung Woo KIM ; Jae Hyeon PARK ; Hoon KIM ; Eun Hwa CHOI ; Seung-Yup KU
Obstetrics & Gynecology Science 2025;68(2):163-173
Objective:
To analyze the microbiological and clinical characteristics of vulvovaginitis in girls, distinguishing between the premenarcheal and postmenarcheal groups in a tertiary center in South Korea.
Methods:
This retrospective cohort study included 195 patients under 20 years of age diagnosed with vulvovaginitis at a tertiary hospital between 2014 and 2023. The patients were categorized into premenarcheal (n=95) and postmenarcheal (n=100) groups. Data on initial symptoms, microbial cultures, and treatment methods were analyzed.
Results:
The most common initial symptom was vaginal discharge, reported in 63.1% of cases. Culture results showed a 51.3% positivity rate for any microorganism, with a prevalence of gram-negative rods (32.8%) and gram-positive cocci (14.4%). The most frequently isolated microorganisms were Escherichia coli (17.9%), Candida albicans (7.7%), and Enterococcus faecalis (6.7%). Gram-negative rods were more common in the premenarcheal group (37.1% vs. 25.0%; p=0.01). No significant differences were observed in the prevalence of gram-positive cocci and Candida species between the two groups (16.8% vs. 12.0%, p=0.22; 6.3% vs. 13.0%, p=0.09; respectively). The susceptibilities of grampositive microorganisms to penicillin, oxacillin, clindamycin, vancomycin, and tetracycline were 58.8%, 58.3%, 94.7%, 100.0%, and 73.7%, respectively. The susceptibilities of gram-negative microorganisms to amoxicillin/clavulanic acid, ciprofloxacin, ceftriaxone, and nitrofurantoin were 89.3%, 85.3%, 76.0%, and 100.0%, respectively.
Conclusion
This study identified differences in the microbial profiles associated with vulvovaginitis between premenarcheal and postmenarcheal girls. Age-specific and history-based clinical approaches tailored to menarcheal status are warranted to improve the management and outcomes of pediatric and adolescent vulvovaginitis.

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