BackgroundThe breast is a rare extranodal site of non-Hodgkin lymphoma, and primary breast lymphoma (PBL) has been arbitrarily defined as disease localized to one or both breasts with or without regional lymph nodes involvement. The aim of this study was to evaluate the clinical outcomes in patients with diffuse large B cell lymphoma (DLBCL) and breast involvement, and to find the criteria of PBL reflecting the outcome and prognosis.MethodsWe retrospectively analyzed data from 68 patients, newly diagnosed with DLBCL and breast involvement at 16 Korean institutions between January 1994 and June 2009.ResultsMedian age at diagnosis was 48 years (range, 20-83 years). Forty-three (63.2%) patients were PBL according to previous arbitrary criteria, sixteen (23.5%) patients were high-intermediate to high risk of international prognostic index. The patients with one extranodal disease in the breast (OED) with or without nodal disease were 49 (72.1%), and those with multiple extranodal disease (MED) were 19 (27.9%). During median follow-up of 41.5 months (range, 2.4-186.0 months), estimated 5-year progression-free survival (PFS) was 53.7 ± 7.6%, and overall survival (OS) was 60.3 ± 7.2%. The 5-year PFS and OS was significantly higher for patients with the OED group than those with the MED group (5-year PFS, 64.9 ± 8.9% vs. 27.5 ± 11.4%, p = 0.001; 5-year OS, 74.3 ± 7.6% vs. 24.5 ± 13.0%, p < 0.001). In multivariate analysis, MED (hazard ratio [HR], 3.61; 95% confidence interval [CI], 1.07-12.2) and fewer than four cycles of systemic chemotherapy with or without local treatments (HR, 4.47; 95% CI, 1.54-12.96) were independent prognostic factors for worse OS. Twenty-five (36.8%) patients experienced progression, and the cumulative incidence of progression in multiple extranodal sites or other than breasts and central nervous system was significantly different between the OED group and the MED group (5-year cumulative incidence, 9.7 ± 5.4% vs. 49.0 ± 15.1%, p = 0.001).ConclusionsOur results show that the patients included in OED group, reflecting different treatment outcome, prognosis and pattern of progression, should be considered as PBL in the future trial. Further studies are warranted to validate our suggested criteria.

Since severe acute respiratory syndrome-coronavirus-2 variant B.1.1.529 (omicron) was first reported to the World Health Organization on November 24, 2021, the cases of the omicron variant have been detected in more than 90 countries over the last month. We investigated the clinical and epidemiological characteristics of the first 40 patients with the omicron variant who had been isolated at the National Medical Center in South Korea during December 4–17, 2021. The median age of the patients was 39.5 years. Twenty-two patients (55%) were women. Seventeen patients (42.5%) were fully vaccinated, and none were reinfected with the omicron. Eighteen (45%) had recent international travel history. Half of the patients (19, 47.5%) were asymptomatic, while the others had mild symptoms. Six patients (15%) showed lung infiltrations on chest image; however, none required supplemental oxygen. These mild clinical features are consistent with recent case reports on the omicron variant from other countries.

Stretch‐activated channels (SACs) were studied in isolated rat atrial myocytes using the whole‐cell and single‐channel patch clamp techniques. Longitudinal stretch was applied by using two patch electrodes. In current clamp configuration, mechanical stretch of 20 % of resting cell length depolarised the resting membrane potential (RMP) from ‐63·6 ± 0·58 mV (n= 19) to ‐54·6 ± 2·4 mV (n= 13) and prolonged the action potential duration (APD) by 32·2 ± 8·8 ms (n= 7). Depolarisation, if strong enough, triggered spontaneous APs. In the voltage clamp configuration, stretch increased membrane conductance in a progressive manner. The current‐voltage (I–V) relationship of the stretch‐activated current (ISAC) was linear and reversed at ‐6·1 ± 3·7 mV (n= 7). The inward component of ISAC was abolished by the replacement of Na+ with NMDG+, but ISAC was hardly altered by the Cl− channel blocker DIDS or removal of external Cl−. The permeability ratio for various cations (PCs:PNa:PLi= 1·05:1:0·98) indicated that the SAC current was a non‐selective cation current (ISAC,NC). The background current was also found to be non‐selective to cations (INSC,b); the permeability ratio (PCs:PNa:PLi= 1·49:1:0·70) was different from that of ISAC,NC. Gadolinium (Gd3+) acted on INSC,b and ISAC,NC differently. Gd3+ inhibited INSC,b in a concentration‐dependent manner with an IC50 value of 46·2 ± 0·8 μM (n= 5). Consistent with this effect, Gd3+ hyperpolarised the resting membrane potential (‐71·1 ± 0·26 mV, n= 9). In the presence of Gd3+ (0·1 mM), stretch still induced ISAC,NC and diastolic depolarisation. Single‐channel activities were recorded in isotonic Na+ and Cs+ solutions using the inside‐out configuration. In NMDG+ solution, outward currents were abolished. Gd3+ (100 μM) strongly inhibited channel opening both from the inside and outside. In the presence of Gd3+ (100 μM) in the pipette solution, an increase in pipette pressure induced an increase in channel opening (21·27 ± 0·24 pS; n= 7), which was distinct from background activity. We concluded from the above results that longitudinal stretch in rat atrial myocytes induces the activation of non‐selective cation channels that can be distinguished from background channels by their different electrophysiology and pharmacology.

Background: The fatality rate of patients with coronavirus disease 2019 (COVID-19) varies among countries owing to demographics, patient comorbidities, surge capacity of healthcare systems, and the quality of medical care. We assessed the clinical outcomes of patients with COVID-19 during the first wave of the epidemic in Korea. Methods: Using a modified World Health Organization clinical record form, we obtained clinical data for 3,060 patients with COVID-19 treated at 55 hospitals in Korea. Disease severity scores were defined as: 1) no limitation of daily activities; 2) limitation of daily activities but no need for supplemental oxygen; 3) supplemental oxygen via nasal cannula; 4) supplemental oxygen via facial mask; 5) non-invasive mechanical ventilation; 6) invasive mechanical ventilation; 7) multi-organ failure or extracorporeal membrane oxygenation therapy; and 8) death. Recovery was defined as a severity score of 1 or 2, or discharge and release from isolation. Results: The median age of the patients was 43 years of age; 43.6% were male. The median time from illness onset to admission was 5 days. Of the patients with a disease severity score of 3-4 on admission, 65 (71.5%) of the 91 patients recovered, and 7 (7.7%) died due to illness by day 28. Of the patients with disease severity scores of 5-7, 7 (19.5%) of the 36 patients recovered, and 8 (22.2%) died due to illness by day 28. None of the 1,324 patients who were < 50 years of age died; in contrast, the fatality rate due to illness by day 28 was 0.5% (2/375), 0.9% (2/215), 5.8% (6/104), and 14.0% (7/50) for the patients aged 50-59, 60-69, 70-79, and ≥ 80 years of age, respectively. Conclusion: In Korea, almost all patients of < 50 years of age with COVID-19 recovered without supplemental oxygen. In patients of ≥ 50 years of age, the fatality rate increased with age, reaching 14% in patients of ≥ 80 years of age.

Background This study aimed to evaluate the current overall preventable trauma death rate (PTDR) in Korea and identify factors associated with preventable trauma death (PTD). Methods The target sample size for review was designed to be 1,131 deaths in 60 emergency medical institutions nationwide. The panels for the review comprised trauma specialists working at the regional trauma centers (RTCs); a total of 10 teams were formed. The PTDR and factors associated with PTD were analyzed statistically. Results Of the target cases, 943 were able to undergo panel review and be analyzed statistically. The PTDR was 30.5% (6.1% preventable and 24.4% possibly preventable). Those treated at a RTC showed a significantly lower PTDR than did those who were not (21.9% vs. 33.9%; P = 0.002). The PTDR was higher when patients were transferred from other hospitals than when they directly visited the last hospital (58.9% vs. 28.4%; P = 0.058; borderline significant). The PTDR increased gradually as the time from accident to death increased; a time of more than one day had a PTDR 14.99 times higher than when transferred within one hour (95% confidence interval, 4.68 to 47.98). Conclusion Although the PTDR in Korea is still high compared to that in developed countries, it was lower when the time spent from the accident to the death was shorter and the final destined institution was the RTC. To reduce PTDR, it is necessary to make an effort to transfer trauma patients to RTCs directly within an appropriate time.

ObjectivesWe conducted a systematic review and meta-analysis to summarize current evidence regarding the association of parity and duration of breastfeeding with the risk of epithelial ovarian cancer (EOC).MethodsA systematic search of relevant studies published by December 31, 2015 was performed in PubMed and EMBASE. A random-effect model was used to obtain the summary relative risks (RRs) and 95% confidence intervals (CIs).ResultsThirty-two studies had parity categories of 1, 2, and ≥3. The summary RRs for EOC were 0.72 (95% CI, 0.65 to 0.79), 0.57 (95% CI, 0.49 to 0.65), and 0.46 (95% CI, 0.41 to 0.52), respectively. Small to moderate heterogeneity was observed for one birth (p<0.01; Q=59.46; I2=47.9%). Fifteen studies had breastfeeding categories of <6 months, 6-12 months, and >13 months. The summary RRs were 0.79 (95% CI, 0.72 to 0.87), 0.72 (95% CI, 0.64 to 0.81), and 0.67 (95% CI, 0.56 to 0.79), respectively. Only small heterogeneity was observed for <6 months of breastfeeding (p=0.17; Q=18.79, I2=25.5%). Compared to nulliparous women with no history of breastfeeding, the joint effects of two births and <6 months of breastfeeding resulted in a 0.5-fold reduced risk for EOC.ConclusionsThe first birth and breastfeeding for <6 months were associated with significant reductions in EOC risk.

In the culture system using human feeder cells, the mechanism through which these cells support undifferentiated growth of embryonic stem cells (ESCs) has not been well investigated. Here, we explored the mechanisms of 3 kinds of human feeder cells, including human placental cells from the chorionic plate, human bone marrow stromal cells, and human foreskin fibroblasts. First, we determined that undifferentiated growth of 2 kinds each of human (H1 and HSF6) and mouse (D3 and CE3) ESCs was possible in all human feeder cell types tested (human placental cells, human bone marrow stromal cells, and human foreskin fibroblasts), without the need for exogenous cytokine supplementation including basic fibroblast growth factor (bFGF) and leukemia inhibitory factor. We then prepared their corresponding endogenous bFGF-knockout feeders using siRNA and tried to maintain human and mouse ESCs in their undifferentiated state; however, neither human nor mouse ESCs could be maintained in bFGF-knockout human feeder cells. The expressions of stemness markers such as Oct-4 and Nanog were significantly decreased in the bFGF-knockout group compared with those in the controls, and differentiation had already occurred, despite the undifferentiated morphologic appearance of the ESCs. In conclusion, human feeder cells are able to support the undifferentiated growth of human and mouse ESCs via bFGF synthesis. Further, a bFGF-dependent pathway might be crucial for maintaining the undifferentiated characteristics of mouse and human ESCs.

Febrile neutropenia (FN) is a frequent complication of cancer chemotherapy, which causes death in 4-21% of patients and worsens the quality of life of patients. As a simple and accurate way of identifying patients who are at risk of FN, a lymphocyte count on post-chemotherapy day 5 was suggested. To confirm the feasibility of this method and to define the incidence of FN among our own patient group, we conducted this prospective study. From September 2001 to February 2002, patients who received cytotoxic chemotherapy at Guro Hospital, Korea University, were enrolled. Blood sampling for a complete blood count was done on the starting day of chemotherapy and on day 3 and day 5 post-chemotherapy. The prospective results of the CBC were compared between the FN group and non-FN group. During the study period, 82 patients were enrolled. The male to female ratio was 52:30, and the median age was 56 years old (range: 14-78). Underlying malignancies were non-Hodgkin's lymphoma (14 patients), stomach cancer (17), breast cancer (11), NSCLC (7), hepatobiliary cancer (10), sarcoma (3), colorectal cancer (3), and others (17). The incidence of FN was 18% (15/82 patients), and ANC at the time of FN was 275 ± 327/µl. Duration of fever was 3.9 ± 3.5 days. The incidence of FN was significantly higher in patients with lymphocyte counts at day 3 ≤ 500/µl (P = 0.06), day 5 ≤ 500/µl (P = 0.023), day 3 ≤ 700/µl (P = 0.01), and day 5 ≤ 700/µl (P = 0.0001). As a result of a logistic regression test, a day-5 lymphocyte count ≤ 700/µl was identified as an independent risk factor for FN.In conclusion, a day-5 lymphocyte count <700/µl was a risk factor for FN. To strengthen our result, we are planning to validate in a larger patient group. Am.