Hepatic sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) is a rare but severe complication of hematopoietic cell transplantation (HCT) showing high mortality. Multiple risk factors for SOS/VOD were identified, but it is often confused with other hepatic complications due to nonspecific clinical features. Therefore, diagnostic and severity criteria have been re vised several times. The European Society of Blood and Marrow Transplantation suggested a new guideline that excludes the standard duration of development within 21 days, emphasizes late-onset SOS/VOD, and suggests the importance of Doppler ultrasonography. The severity criteria were further subdivided for guidance to begin active treatment using defibrotide which was approved in Korea since 2016. In a phase 3 trial, defibrotide had superior 100-day survival, compared to best available treatments (38.2% vs. 25.0%). Although several studies of SOS/VOD in Korean patients have been performed after the implementation of HCT, most involved small number of pediatric patients. Recently, the Korean Society of Blood and Marrow Transplantation investigated the incidence of SOS/VOD in the Korean population, and several influential studies of adult patients were published. Here, we summarize recent issues regarding the mechanism, diagnosis, severity criteria, prevention, and treatments of SOS/VOD in Korean patients, as well as recent analyses of nationwide incidence.

Previous research has investigated whether hyperuricemia serves as an independent risk factor for cardiovascular and renal diseases. Hyperuricemia is defined as an abnormally high level of uric acid (UA; i.e., serum urate level > 6.8 mg/dL). Hyperuricemia has been considered a complication of chronic kidney disease (CKD). However, it seems to play a pathogenic role in the progression of renal diseases. There has been increasing focus on the link between hyperuricemia and CKD. The results of randomized controlled trials have implied independent associations between hyperuricemia and the progression of cardiovascular and renal morbidities. These associations may be mediated by renin-angiotensin system activation, nitric oxide synthase inhibition, and macrovascular/microvascular disease development. There remains controversy regarding the use of serum UA level as an indirect index of renal vascular disease. This literature review focuses on the role of asymptomatic hyperuricemia in the progression of CKD, as well as the association between hyperuricemia and cardiovascular disease. It also provides a general overview of the physiological metabolism of UA.

Chronic obstructive pulmonary disease (COPD) is a complex lung disease characterized by a combination of airway disease and emphysema. Emphysema is classified as centrilobular emphysema (CLE), paraseptal emphysema (PSE), or panlobular emphysema (PLE), and airway disease extends from the respiratory, terminal, and preterminal bronchioles to the central segmental airways. Although clinical computed tomography (CT) cannot be used to visualize the small airways, micro-CT has shown that terminal bronchiole disease is more severe in CLE than in PSE and PLE, and micro-CT findings suggest that the loss and luminal narrowing of terminal bronchioles is an early pathological change in CLE. Furthermore, the introduction of ultra-high-resolution CT has enabled direct evaluation of the proximal small (1 to 2-mm diameter) airways, and new CT analytical methods have enabled estimation of small airway disease and prediction of future COPD onset and lung function decline in smokers with and without COPD. This review discusses the literature on micro-CT and the technical advancements in clinical CT analysis for COPD. Hopefully, novel micro-CT findings will improve our understanding of the distinct pathogeneses of the emphysema subtypes to enable exploration of new therapeutic targets, and sophisticated CT imaging methods will be integrated into clinical practice to achieve more personalized management.

Approximately 25% to 40% of patients with chronic obstructive pulmonary disease (COPD) have the eosinophilic endotype. It is important to identify this group accurately because they are more symptomatic and are at increased risk for exacerbations and accelerated decline in forced expiratory volume in the 1st second. Importantly, this endotype is a marker of treatment responsiveness to inhaled corticosteroid (ICS), resulting in decreased mortality risk. In this review, we highlight differences in the biology of eosinophils in COPD compared to asthma and the different definitions of the COPD eosinophilic endotype based on sputum and blood eosinophil count (BEC) with the corresponding limitations. Although BEC is useful as a biomarker for eosinophilic COPD endotype, optimal BEC cut- offs can be combined with clinical characteristics to improve its sensitivity and specificity. A targeted approach comprising airway eosinophilia and appropriate clinical and physiological features may improve identification of subgroups of patients who would benefit from biologic therapy or early use of ICS for disease modification.

Background/Aims: The treatment of gastric cancer remains unsatisfactory. We aimed to investigate the prognostic value of immunohistochemical staining in gastric cancer.
Methods: We analyzed 505 (279 early staged, 226 advanced-staged) gastric cancer tissues from patients who underwent radical gastric resection between January 2014 and December 2016. Available surgical specimens immunohistochemically stained for p53, epidermal growth factor receptor (EGFR), human EGFR 2 (HER-2), E-cadherin, and Ki-67 were reviewed. We evaluated the association between positivity to various biomarkers and disease recurrence, disease-free survival, lymph node metastasis, and microscopic lymphovascular invasion.
Results: The median follow-up duration was 32.5 months (range, 7 to 70). Advanced gastric cancer cases showed high Ki-67 expression; other cases showed un-remarkable expression. Concerning disease recurrence, lymphatic invasion, and disease-free interval, all biomarkers had no prognostic effects. HER-2-positive stage I gastric cancer tended to occur in old patients and in the upper one-third of the stomach (p = 0.01). HER-2 positivity was significantly correlated with disease recurrence (p = 0.01), lymphatic invasion (p = 0.03), and vascular invasion (p = 0.03) in stage I cases.
Conclusions: Only HER-2 was associated with the recurrence of stage I gastric cancer. HER-2-positive stage I gastric cancer requires additional therapy despite curative resection.

Background/Aims: Postoperative abdominal fluid collection (PAFC) is a frequent complication of pancreatobiliary cancer surgery. The effects of the existence and duration of PAFC are not well known. This study aimed to assess the effects of PAFC on patient prognosis after surgery for pancreatobiliary adenocarcinoma and the association of longstanding PAFC with the recurrence of pancreatic cancer.
Methods: We retrospectively analyzed the data of 194 consecutive patients with pancreatobiliary adenocarcinoma who underwent curative operations from August 2005 to December 2019. The presence of PAFC was assessed using computed tomography within a week of surgery; PAFC lasting > 4 weeks was defined as longstanding PAFC.
Results: Among 194 patients, PAFC occurred in 165 (85.1%), and 74 of these had longstanding PAFC. The recurrence rate of pancreatobiliary adenocarcinoma was significantly higher in patients with longstanding PAFC than in patients with non-longstanding PAFC (p = 0.025). Recurrence was also significantly associated with high T stage (T3, T4; p = 0.040), lymph node involvement (p < 0.001), perineural invasion (p < 0.006), and non-receipt of adjuvant chemotherapy (p = 0.025). Longstanding PAFC was significantly associated with the recurrence of pancreatic adenocarcinoma (p = 0.016). However, cancer-specific survival was related to neither the presence nor the duration of PAFC.
Conclusions: The presence of longstanding PAFC was associated with the recurrence of pancreatic adenocarcinoma. However, a larger prospective study is necessary to confirm the findings.

Background/Aims: The effect of hyperammonemia on the mortality in patients with liver cirrhosis is well documented. However, little is known about the impact of hyperammonemia on mortality among intensive care unit patients without hepatic disease. We aimed to investigate factors associated with non-hepatic hyperammonemia among intensive care unit patients and to evaluate the factors related to the 7- and 90-day mortality.
Methods: Between February 2016 and February 2020, 948 patients without hepatic disease who had 972 episodes of admission to the intensive care unit were retrospectively enrolled and classified as hyperammonemia grades 0 (≤ 80 μg/dL; 585 [60.2%]), 1 (≤ 160 μg/dL; 291 [29.9%]), 2 (≤ 240 μg/dL; 55 [5.7%]), and 3 (> 240 μg/dL; 41 [4.2%]). Factors associated with hyperammonemia and the 7- and 90-day mortality were evaluated by multivariate logistic regression analysis and Cox regression analysis, respectively. Kaplan-Meier survival curves for the 7- and 90-day mortality were constructed.
Results: The independent risk factors for hyperammonemia were male sex (odds ratio, 1.517), age (0.984/year), acute brain failure (2.467), acute kidney injury (1.437), prothrombin time-international normalized ratio (2.272/unit), and albumin (0.694/g/dL). The 90-day mortality rate in the entire cohort was 24.3% and gradually increased with increasing hyperammonemia grade at admission (17.9%, 28.2%, 43.6%, and 61.0% in patients with grades 0, 1, 2, and 3, respectively). Additionally, non-hepatic hyperammonemia was an independent predictor of the 90- day mortality in intensive care unit patients.
Conclusions: Non-hepatic hyperammonemia is common (39.8%) and associated with the 90-day mortality among intensive care unit patients.

Background/Aims: We aimed to study the clinical characteristics, treatment modality, and the prognosis of synchronous multiple primary esophageal squamous cell carcinomas (SMPESCC).
Methods: A total of 117 SMPESCC cases were evaluated retrospectively from 2010 to 2015.
Results: The most common locations of SMPESCC were mid- and lower thoracic segments (n = 208, 84.9%). The 1-, 2-, and 3-year overall survival rates were 53.8%, 30.8%, and 15.4%, respectively; the median survival time (MST) was 12.5 months. With definitive radiotherapy and surgery, respectively, the MST of stage I/II patients were 34.2 and 26.7 months, of stage III patients were 8.3 and 13.2 months (p = 0.163), and of stage IV patients were and 8 and 12.6 months (p = 0.379). Clinical stage, family history of cancer, and Karnofsky performance status were independent prognostic factors for the whole cohort by Cox multivariate regression analysis (hazard ratio [HR] = 0.859, p < 0.001; HR = 0.579, p = 0.032; and HR = 0.586, p = 0.013).
Conclusions: Although the prognosis of SMPESCC is poor, stage I/II patients can achieve long-term survival with aggressive treatment, especially those with a Karnofsky performance score 90 or higher and who have no family history of cancer. Definitive radiotherapy could achieve a similar survival rate to definitive surgery at different clinical stages.