1.Glymphatic System of the Brain: Anatomy, Physiology, and Clinical Implications
Min Young CHUN ; Seok Jong CHUNG ; Seong Ho JEONG
Journal of the Korean Neurological Association 2026;44(1):8-21
Cerebrospinal fluid (CSF) dynamics are increasingly recognized as central to brain waste clearance. Beyond the classical view of unidirectional CSF circulation, recent studies have identified the glymphatic system and meningeal lymphatic vessels as major complementary pathways. Glymphatic transport is driven by arterial pulsation, respiration, vasomotion, and strongly enhanced during slow-wave sleep. Advances in neuroimaging, including DTI-ALPS, EPVS quantification, contrast-enhanced magnetic resonance imaging (MRI), and ultrafast functional MRI, have enabled in vivo assessment of these mechanisms. Impaired glymphatic function has been linked to neurodegenerative and cerebrovascular diseases, highlighting its clinical relevance. Potential interventions range from lifestyle measures such as sleep optimization, exercise, and vascular risk control, to pharmacological and experimental strategies aiming to modulate CSF flow. These insights open new opportunities to target the glymphatic-lymphatic axis for the prevention and treatment of neurological disorders.
2.Measuring Trends in Disability-adjusted Life Years and Life Expectancy in Korea: 2008 to 2021
Chung-Nyun KIM ; Dawit Urgi GURMU ; Young-Eun KIM ; Yoon-Sun JUNG ; Yongseok CHOI ; Minsu OCK ; Seok-Jun YOON
Journal of Preventive Medicine and Public Health 2026;59(1):25-34
Objectives:
This study, part of the ongoing Korean National Burden of Disease (KNBD) updates, assesses disability-adjusted life years (DALYs) and disability-adjusted life expectancy (DALE) in Korea, taking into account the effects of coronavirus disease 2019 and emphasizing the importance of analyzing these metrics jointly.
Methods:
Data were obtained from Statistics Korea, the National Health Insurance Service, and the Korea Disease Control and Prevention Agency. DALYs and DALE were calculated using an incidence-based approach, following disease classification, disability weights, and estimation procedures consistent with prior KNBD research.
Results:
Compared with earlier estimates, DALYs showed a slight decline in 2020 followed by an increase in 2021, with this pattern observed across all income quintiles. For DALE, both men and women experienced modest gains relative to earlier studies; however, a decrease occurred across all income levels in 2021 compared with 2020. Regional disparities in DALE also narrowed beginning in 2020, with a more marked reduction among women.
Conclusions
Unlike previous studies, this research presents DALYs and DALE concurrently, offering a more comprehensive perspective on summary measures of population health. The post-2020 rise in DALYs underscores the growing need for effective chronic disease management. Additionally, widening income-based disparities in DALE highlight the urgency of addressing health inequities. Continued monitoring and updates of DALYs and DALE are necessary to understand and respond to these evolving trends.
3.Impact of Additional Occipital Involvement in Parkinson’s Disease With Posterior Cortical Hypoperfusion
Chan Wook PARK ; Su Hong KIM ; Phil Hyu LEE ; Yun Joong KIM ; Young H. SOHN ; Yong JEONG ; Seok Jong CHUNG
Journal of Movement Disorders 2026;19(1):58-66
Objective:
This study aims to investigate the clinical relevance of occipital hypoperfusion in patients with Parkinson’s disease (PD) with respect to clinical phenotype and the risk of dementia conversion.
Methods:
We enrolled 349 patients with newly diagnosed PD and 48 healthy controls who underwent dual-phase 18F-N-(3-fluoropropyl)-2β-carboxymethoxy-3β-(4-iodophenyl) nortropane (18F-FP-CIT) positron emission tomography (PET). Patients with PD were classified into three groups based on posterior cortical perfusion patterns on early-phase 18F-FP-CIT PET images: PD with preserved posterior cortical perfusion (n=186), PD with parieto-temporal hypoperfusion (n=84), and PD with parieto-temporo-occipital hypoperfusion (n=79). Baseline clinical features and dementia conversion risk were compared across PD groups.
Results:
Patients with preserved posterior cortical perfusion were younger than those in the other PD groups. Compared with the other groups, the parieto-temporo-occipital hypoperfusion group tended to have lower Cross-Cultural Smell Identification Test scores, a higher prevalence of rapid eye movement sleep behavior disorder, higher Unified PD Rating Scale motor scores, and more severe reductions in striatal dopamine transporter availability. The risk of dementia conversion was lower in patients with preserved posterior cortical perfusion than in those with posterior cortical hypoperfusion. However, the risk of dementia conversion did not differ between the parieto-temporal and parieto-temporo-occipital hypoperfusion groups.
Conclusion
Additional occipital hypoperfusion was not associated with an imminent risk of dementia conversion in patients with PD with posterior cortical hypoperfusion. Nonetheless, occipital involvement may serve as an indicator of the diffuse malignant subtype of PD.
4.Bisphosphonates as a Tacrolimus-Sparing Strategy in Kidney Transplantation: Insights from a Retrospective Analysis
Hee Byung KOH ; Hyo Jeong KIM ; Ga Young HEO ; Namki HONG ; Yaeji LEE ; Seung Hwan SONG ; Hoon Young CHOI ; Chan-Young JUNG ; Hyung Woo KIM ; Jaeseok YANG ; Kyu Ha HUH ; Chung Mo NAM ; Beom Seok KIM
Yonsei Medical Journal 2026;67(1):17-26
Purpose:
Due to chronic toxicity, tacrolimus-sparing is an important issue in kidney transplant recipients (KTRs). Several studies have shown that bisphosphonate use is associated with favorable graft outcomes in KTRs. We investigated whether the association between tacrolimus trough levels (TTLs) and graft outcomes differed according to bisphosphonate use in KTRs.
Materials and Methods:
We conducted a retrospective study encompassing 1441 KTRs who were administered tacrolimus-based immunosuppressants. The primary exposure was a time-dependent cross-product of TTLs (low TTLs vs. normal-high TTLs with a reference of 6 ng/mL) and bisphosphonate use. Two primary outcomes were evaluated: overall graft loss (death or conversion to kidney replacement) and an estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m 2 .
Results:
During the median follow-up of 6.1 (3.4–9.7) years, overall graft loss occurred in 157 (10.9%) patients. Cox regression revealed that normal-high TTLs without bisphosphonate use were associated with a reduced risk of overall graft loss [adjusted hazard ratio (aHR), 0.65; 95% confidence interval (CI), 0.45–0.95] compared to low TTLs without bisphosphonate use. The use of bisphosphonate in conjunction with normal-high TTLs correlated with an even lower risk of overall graft loss (aHR, 0.25; 95% CI, 0.08–0.80) compared with low TTLs without bisphosphonate use. In patients with low TTLs, bisphosphonate use was associated with a reduced risk of overall graft loss compared with non-use (aHR, 0.20; 95% CI, 0.09–0.43). Similar trends were observed in the eGFR outcome.
Conclusion
The use of bisphosphonate was associated with favorable graft outcomes, even with low TTLs. Incorporating bisphosphonate into a conventional immunosuppressant regimen may potentially reduce tacrolimus requirement.
5.Korean Thyroid Association Guidelines on the Management of Differentiated Thyroid Cancers; Part II. Follow-up Surveillance after Initial Treatment 2026
Eun Kyung LEE ; Seung Heon KANG ; Bon Seok KOO ; Mijin KIM ; Min Joo KIM ; Bo Hyun KIM ; Ji Won KIM ; Dong Gyu NA ; Sohyun PARK ; Ji-In BANG ; Kyorim BACK ; Youngduk SEO ; Young-Ik SON ; Young Shin SONG ; Dong Yeob SHIN ; Jong-Hyuk AHN ; Hwa Young AHN ; So Won OH ; Ho-Ryun WON ; Won Sang YOO ; Min Kyoung LEE ; Sang-Woo LEE ; Jeongmin LEE ; Ji Ye LEE ; Dong-Jun LIM ; Ki-Wook CHUNG ; Ari CHONG ; Jin Hyang JUNG ; Sun Wook CHO ; Yoon Young CHO ; Chae Moon HONG ; Young Joo PARK ;
International Journal of Thyroidology 2026;19(1):1-40
In patients with differentiated thyroid cancer (DTC), initial recurrence risk stratification based on clinical, histopathological, and perioperative data remains the key determinant for guiding management strategies during the first 1-2 years post-treatment. However, the adoption of ongoing risk stratification (ORS), which dynamically reassesses risk by integrating longitudinal clinical data and treatment response, enables more precise long-term prognostic assessment and facilitates highly individualized management. Building upon recent guidelines, the 2026 KTA guideline has been further refined by incorporating robust evidence from large-scale national cohorts and comprehensive systematic reviews. These updated recommendations outline contemporary concepts of ORS, risk-adapted TSH suppression targets, optimized surveillance modalities for recurrence detection, and disease-specific long-term follow-up strategies. Reflecting the paradigm shift toward de-escalated treatment, this revision integrates evolved perspectives on TSH suppression intensity, the clinical interpretation of thyroglobulin levels, and tailored follow-up intervals. These evidence-based recommendations aim to minimize unnecessary treatment and excessive surveillance in the large proportion of patients with excellent prognosis after initial therapy, while ensuring that each patient receives appropriately tailored and effective long-term management.
6.A Real-World Efficacy and Safety of KEYNOTE-522 Regimen in Patients With Early Triple-Negative Breast Cancer
Shinyoung LEE ; Hyehyun JEONG ; Yeokyeong SHIN ; Jae Ho JEONG ; Kyung Hae JUNG ; Sung-Bae KIM ; Byung-Kwan JEONG ; Hee Jin LEE ; Gyungyub GONG ; Hee Jung SHIN ; Hye Joung EOM ; Young-Jin LEE ; Tae-Kyung YOO ; Sae Byul LEE ; Jisun KIM ; Il-Yong CHUNG ; Beom-Seok KO ; Hee Jeong KIM ; Jong Won LEE ; Byung Ho SON ; Jin-Hee AHN
Journal of Breast Cancer 2026;29(2):141-153
Purpose:
Based on the KEYNOTE-522 study, neoadjuvant pembrolizumab plus chemotherapy has become the standard treatment for early-stage triple-negative breast cancer (TNBC).This study evaluated the real-world efficacy, safety, and predictors of pathologic complete response (pCR) in Korean patients.
Methods:
We conducted a retrospective cohort study of 174 patients with early-stage TNBC who received the KEYNOTE-522 regimen (neoadjuvant pembrolizumab plus paclitaxel and carboplatin, followed by doxorubicin and cyclophosphamide) at a tertiary cancer center between August 2022 and July 2024. We assessed the primary endpoints, including pCR rate and event-free survival (EFS). We performed univariable and multivariable logistic regression analyses to identify independent predictors of pCR.
Results:
The median patient age was 50 years (range, 24–74 years). The clinical stages were II and III in 79.3% and 20.1% of patients, respectively, and 10.9% had clinical N3 disease. The overall pCR rate was 62.1%, and the N3 subgroup had a pCR rate of 47.4%. On multivariable analysis, high baseline Ki-67 expression (≥ median, 75%) was significantly associated with pCR (odds ratio, 2.84; 95% confidence interval, 1.45 to 5.66; p = 0.002). At a median followup of 18.4 months, the 12-month EFS rate was 97.4%, with significantly superior outcomes observed in patients who achieved pCR compared with those who did not achieve pCR (100% vs. 93.1%, p = 0.007). The treatment completion rate was 92.0%, and immune-related adverse events occurred in 13.8% of patients.
Conclusion
In this real-world analysis of one of the largest Asian cohorts of patients with earlystage TNBC treated with neoadjuvant pembrolizumab, the KEYNOTE-522 regimen demonstrated substantial efficacy and manageable toxicity, consistent with the original trial findings.
7.Treatment of Helicobacter pylori Infection in Korea: An Evidence-Based Analysis of the Upcoming 2025 Guideline
Chang Seok BANG ; Seung Joo KANG ; Su Youn NAM ; Sung Eun KIM ; Seung Young KIM ; Hyunchul LIM ; Chung Hyun TAE ; Moon Won LEE ; Seung Han KIM ; Hye-Kyung JUNG ; Byung-Wook KIM
The Korean Journal of Helicobacter and Upper Gastrointestinal Research 2026;26(1):23-36
The efficacy of clarithromycin-containing triple therapy (TT) against Helicobacter pylori has declined in Korea, with recent first-line eradication rates falling below 70%. Clarithromycin resistance exceeded 30%, undermining the standard regimen for H. pylori. These trends necessitate a change in the treatment strategy. This review analyzed the shift proposed in the draft of the 2025 Korean H. pylori guidelines. We examined the rationale for abandoning TT as a first-line empirical therapy and the establishment of a new dual-pillar strategy: 1) the declining role of clarithromycin-containing TT as a first-line treatment and 2) polymerase chain reaction (PCR)-based tailored therapy as the recommended precision approach. We explored the 1) emergence of new empirical regimen options, 2) application of tailored therapy, and 3) adoption of potassium-competitive acid blockers (P-CABs). Empirical regimens have shifted toward four-drug combinations to achieve higher cure rates. Concomitant therapy (proton-pump inhibitor [PPI] or P-CAB+amoxicillin+clarithromycin+metronidazole) offers high efficacy but raises concerns about antibiotic overuse. As a compromise, bismuth-augmented triple regimens (adding bismuth to TT) are now recommended; these modified quadruple therapies (e.g., PACB: PPI+amoxicillin+clarithromycin+bismuth, or PAMB: PPI+amoxicillin+metronidazole+bismuth) significantly improve eradication rates without requiring a third antibiotic class. Regarding tailored therapy, PCR-based domestic clinical research data consistently achieves ≥90% cure rates in first-line treatment—markedly higher than empirical TT in Korea. Economic analyses supported the cost-effectiveness of this approach. The guideline algorithm for salvage therapy was clarified. Bismuth quadruple therapy has been confirmed as the standard second-line treatment. For third-line therapy, we analyzed the efficacy of levofloxacin-based regimens, rifabutin-based therapy, and bismuth add-on therapy with two previously unused antibiotics. The 2025 Korean guidelines establish quadruple therapies as the new standard through a dual strategy: pragmatic empirical treatment and PCR-guided tailored therapy, with P-CABs and bismuth-based regimens as key components.
8.Emerging Innovations in Acne Management: A Focus on NonPharmacological Therapeutic Devices
Ji Yeon HONG ; Joon SEOK ; Hye Sung HAN ; Kui Young PARK
Journal of Korean Medical Science 2025;40(9):e118-
Acne is a chronic inflammatory condition affecting the sebaceous glands, with approximately 80% of individuals experiencing it at some point in their lives. Among adolescents, the incidence is reported to exceed 85%. The disease can significantly impact both physical and emotional aspects of a person’s quality of life, leading to permanent scarring, poor self-image, depression, and anxiety. The standard first-line treatment for acne vulgaris includes conventional pharmacological approaches such as keratolytics, topical or oral antibiotics, retinoids, and hormonal agents. However, these treatments are not universally effective due to patient noncompliance, adverse drug effects, and the emergence of antibiotic resistance in Cutibacterium acnes, often resulting in high rates of recurrence. Consequently, non-pharmacological therapies have been developed as safe and effective alternatives or supplements to pharmacological treatment. These non-pharmacological approaches can serve as standalone treatment modalities, adjuncts to pharmacological therapy, or maintenance treatments. Current literature lacks comprehensive data on the classification of these non-pharmacological treatment options. This paper aims to provide a brief overview of recent research on the practical applications and potential mechanisms of nonpharmacological therapies for both acne and acne scars. Through elucidating the distinct mechanisms and therapeutic roles of these treatments, we aim to assist dermatologists and other healthcare providers in formulating more effective disease management strategies, thereby encouraging further research in this area.
10.A Case of a Cataract Patient with Equatorial and Posterior Zonular Weakness in Both Eyes
Jeong Woo KWON ; In Seok JEONG ; In Young CHUNG ; Seong Wook SEO ; Seong Jae KIM
Journal of the Korean Ophthalmological Society 2025;66(4):209-213
Purpose:
We present a case of equatorial and posterior zonular weakness observed during cataract surgery in both eyes with no prior history of trauma or surgery.Case summary: A 73-year-old woman visited out clinic and reported decreased visual acuity. She was found to have a best corrected visual acuity of 0.5 in both eyes. Cataracts were noted during a slit lamp examination and cataract surgery was subsequently performed. During the left eye surgery, although there was no evident weakening during the anterior capsulotomy, the equatorial and posterior zonules were damaged during phacoemulsification. This led to consistent aspiration of the equatorial and posterior capsule (PC) into the phaco-handpiece tip during epinucleus and cortex removal. The PC eventually ruptured necessitating anterior vitrectomy and a 3-piece intraocular lens insertion into the ciliary sulcus. Two weeks later, the right eye surgery encountered similar challenges in removing the epinucleus and cortex. The surgery was completed successfully by elevating the irrigation bottle, frequently injecting an ophthalmic viscoelastic device (OVD), and removing the remaining lens material using a bimanual irrigator/aspirator.
Conclusions
This case highlights that equatorial and posterior zonular weakness can occur in the absence of trauma or prior to surgery. To manage such cases, it is advisable to elevate the irrigation bottle height, continuously inject OVD during surgery, and use a bimanual irrigator/aspirator.

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