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.

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.

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.

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.