Viral load and the duration of viral shedding of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are important determinants of the transmission of coronavirus disease 2019.In this study, we examined the effects of viral doses on the lung and spleen of K18-hACE2 transgenic mice by temporal histological and transcriptional analyses. Approximately, 1×105 plaque-forming units (PFU) of SARS-CoV-2 induced strong host responses in the lungs from 2 days post inoculation (dpi) which did not recover until the mice died, whereas responses to the virus were obvious at 5 days, recovering to the basal state by 14 dpi at 1×102 PFU. Further, flow cytometry showed that number of CD8+ T cells continuously increased in 1×102 PFU-virusinfected lungs from 2 dpi, but not in 1×105 PFU-virus-infected lungs. In spleens, responses to the virus were prominent from 2 dpi, and number of B cells was significantly decreased at 1×105PFU; however, 1×102 PFU of virus induced very weak responses from 2 dpi which recovered by 10 dpi. Although the defense responses returned to normal and the mice survived, lung histology showed evidence of fibrosis, suggesting sequelae of SARS-CoV-2 infection. Our findings indicate that specific effectors of the immune response in the lung and spleen were either increased or depleted in response to doses of SARS-CoV-2. This study demonstrated that the response of local and systemic immune effectors to a viral infection varies with viral dose, which either exacerbates the severity of the infection or accelerates its elimination.

Background: Sterility and safety assurance of hematopoietic stem cell (HSC) products is critical in transplantation. Microbial contamination can lead to product disposal and increases the risk of unsuccessful clinical outcomes. Therefore, it is important to implement and maintain good practice guidelines and regulations for the HSC collection and processing unit in each hospital. We aimed to share our experiences and suggest strategies to improve the quality assurance of HSC processing. Methods: We retrospectively analyzed microbial culture results of 11,743 HSC products processed over a 25-year period (January 1996 to May 2021). Because of reorganization of the HSC management system in 2008, the 25-year period was divided into periods 1 (January 1996 to December 2007) and 2 (January 2008 to May 2021). We reviewed all culture results of the HSC products and stored aliquot samples and collected culture results for peripheral blood and catheter samples. Results: Of the 11,743 products in total, 35 (0.3%) were contaminated by microorganisms, including 19 (0.5%) of 3,861 products during period 1 and 16 (0.2%) of 7,882 products during period 2. Penicillium was the most commonly identified microorganism (15.8%) during period 1 and coagulase-negative Staphylococcus was the most commonly identified (31.3%) during period 2. HSC product contamination occurred most often during HSC collection and processing. Conclusions The contamination rate decreased significantly during period 2, when the HSC management system was reorganized. Our results imply that handling HSC products by trained personnel and adopting established protocols, including quality assurance programs, aid in decreasing the contamination risk.

Thyroid hormone plays a vital role in regulating human metabolism. They affect the functions of major organs, such as the brain, liver, skeletal muscle, and heart. Hypothyroidism can lead to dilated cardiomyopathy and decreased heart function. In this report, we describe a case of a teenage boy who developed dilated cardiomyopathy due to hypothyroidism and was considered to undergo heart transplantation. Levothyroxine monotherapy was initiated but produced no improvement. Thereafter, a combination therapy of liothyronine and levothyroxine was administered, and heart function was gradually restored; he recovered completely after 6 months. Cardiac myocytes respond more specifically to liothyronine than to levothyroxine. Therefore, we suggest that liothyronine and levothyroxine combination therapy should be considered rather than levothyroxine monotherapy for hypothyroidism accompanied by heart disease.

Purpose: The activity and safety of neoadjuvant nivolumab plus gemcitabine/cisplatin (N+GC) were tested in patients with muscle-invasive bladder urothelial carcinoma (MIBC). Materials and Methods: In a prospective phase II trial, patients with cT2-T4a N0 MIBC who were eligible for cisplatin and medically appropriate to undergo radical cystectomy (RC) were enrolled. Treatment with nivolumab 3 mg/kg on days 1 and 15 plus GC (cisplatin 70 mg/m2 on day 1, and gemcitabine 1,000 mg/m2 on days 1, 8, and 15) was repeated every 28 days up to 3 or 4 cycles, depending on the surgery schedules. The primary endpoint was pathologic complete response (pCR, ypT0). Secondary endpoints included pathologic downstaging (≤ ypT1), disease-free survival (DFS), and safety. Results: Between September 2019 and October 2020, 51 patients were enrolled. Neoadjuvant N+GC was well tolerated. Among 49 patients who completed neoadjuvant N+GC, clinical complete response (cCR) was achieved in 59% of intent-to-treat (ITT) population. RC was performed in 34 (69%) patients. pCR was achieved in 24% (12/49) of ITT population and 35% (12/34) of RC patients. Median DFS was not reached. Over a median follow-up of 24 months, 12 patients experienced disease recurrence and were treated with palliative therapy or surgery. Although 12 patients declined surgery and were treated with concurrent chemoradiotherapy, DFS was longer in patients with cCR after neoadjuvant therapy than those without. Preoperative programmed death-ligand 1 (PD-L1) did not correlate with pCR or pathologic downstaging rates. Conclusion Neoadjuvant N+GC was feasible and provided meaningful pathologic responses in patients with MIBC, regardless of baseline PD-L1 expression (ONO-4538-X41; CRIS.nih.go.kr, KCT0003804).

Background: Exercise is recommended for type 2 diabetes mellitus (T2DM) patients to prevent cardiovascular disease. However, the effects of physical activity (PA) for reducing the risk of heart failure (HF) has yet to be elucidated. We aimed to assess the effect of changes in patterns of PA on incident HF, especially in newly diagnosed diabetic patients. Methods: We examined health examination data and claims records of 294,528 participants from the Korean National Health Insurance Service who underwent health examinations between 2009 and 2012 and were newly diagnosed with T2DM. Participants were classified into the four groups according to changes in PA between before and after the diagnosis of T2DM: continuously inactive, inactive to active, active to inactive, and continuously active. The development of HF was analyzed until 2017. Results: As compared with those who were continuously inactive, those who became physically active after diagnosis showed a reduced risk for HF (adjusted hazard ratio [aHR], 0.79; 95% confidence interval [CI], 0.66 to 0.93). Those who were continuously active had the lowest risk for HF (aHR, 0.77; 95% CI, 0.62 to 0.96). As compared with those who were inactive, those who exercised regularly, either performing vigorous or moderate PA, had a lower HF risk (aHR, 0.79; 95% CI, 0.69 to 0.91). Conclusion Among individuals with newly diagnosed T2DM, the risk of HF was reduced in those with higher levels of PA after diagnosis was made. Our results suggest either increasing or maintaining the frequency of PA after the diagnosis of T2DM may lower the risk of HF.

Purpose: There are few reports on outcomes following surgical repair of recurrent rectal prolapse. The purpose of this study was to examine surgical outcomes for recurrent rectal prolapse. Methods: We conducted a multicenter retrospective study of patients who underwent surgery for recurrent rectal prolapse. This study used data collected by the Korean Anorectal Physiology and Pelvic Floor Disorder Study Group. Results: A total of 166 patients who underwent surgery for recurrent rectal prolapse were registered retrospectively between 2011 and 2016 in 8 referral hospitals. Among them, 153 patients were finally enrolled, excluding 13 patients who were not followed up postoperatively. Median follow-up duration was 40 months (range, 0.2–129.3 months). Methods of surgical repair for recurrent rectal prolapse included perineal approach (n = 96) and abdominal approach (n = 57). Postoperative complications occurred in 16 patients (10.5%). There was no significant difference in complication rate between perineal and abdominal approach groups. While patients who underwent the perineal approach were older and more fragile, patients who underwent the abdominal approach had longer operation time and admission days (P < 0.05). Overall, 29 patients (19.0%) showed re-recurrence after surgery. Among variables, none affected the re-recurrence. Conclusion For the recurrent rectal prolapse, the perineal approach is used for the old and fragile patients. The postoperative complications and re-recurrence rate between perineal and abdominal approach were not different significantly. No factor including surgical method affected re-recurrence for recurrent rectal prolapse.

Purpose: To differentiate a non-cancer-related temporary increase in prostate-specific antigen (PSA) triggering unnecessary biopsy, we intentionally delayed biopsy with a serial follow-up, then investigated the efficacy of this strategy in identifying a significant prostate cancer (PCa). Materials and Methods: Retrospective data of patients who initially presented with a suspicious level of serum PSA (3–20 ng/mL), managed using the delayed strategy, and then eventually underwent biopsy were obtained from 4 tertiary centers between 2018–2020. Results: The collected 271 subjects had a median (interquartile range) PSA, age, and prostate volume of 5.03 ng/mL (4.46–7.79 ng/mL), 67 years (61–73 years), and 38 g (28–50 g), respectively. During the delay period of 8 weeks (4–19 weeks), most were managed with alpha-blockers (85.6%, n=232). Ninety-four (34.7%) experienced a PSA decrease of 20.53% (8.82–38.16). Eventual biopsy revealed 115 PCa cases (42.5%) including 82 significant ones and 46 high-risk diseases. Men with a PSA decrease had a lower probability of PCa (31.9% vs. 48%, p=0.014), a significant disease (21.3% vs. 35.0%, p=0.026), and high-risk PCa (7.4% vs. 22.0%, p=0.002) than the PSA-elevated counterparts. However, the degree of PSA decrease was not associated with the presence or the severity of PCa. In patients with PSA normalization (≤3 ng/mL), though 4 patients of them (66%) had PCa including a single significant disease, none had high-risk disease. Conclusions About one-third of individuals initially indicated for transrectal biopsy experienced a decrease in PSA, and their chance for significant PCa was diminished. This retrospective study suggests PSA normalization could be an acceptable notion, though requires further investigation.

Purpose: Febrile neutropenia (FN) can cause suboptimal treatment and treatment-related mortality (TRM) in diffuse large B-cell lymphoma (DLBCL) patients treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP). Materials and methods: We conducted a prospective cohort study to evaluate the effectiveness of pegfilgrastim prophylaxis in DLBCL patients receiving R-CHOP, and we compared them with the PROCESS cohort (n=485). Results: Since January 2015, 986 patients with DLBCL were enrolled. Pegfilgrastim was administered at least once in 930 patients (94.3%), covering 90.3% of all cycles. FN developed in 137 patients (13.9%) in this cohort (23.7% in the PROCESS cohort, p<0.001), and 4.2% of all cycles (10.2% in the PROCESS cohort, p<0.001). Dose delay was less common (≥3 days: 18.1% vs. 23.7%, p=0.015; ≥5 days: 12.0% vs. 18.3%, p=0.023) in this cohort than in the PROCESS cohort. The incidence of TRM (3.2% vs. 5.6%, p=0.047) and infection-related death (1.8% vs. 4.5%, p=0.004) was lower in this cohort than in the PROCESS cohort. The 4-year overall survival (OS) and progression-free survival (PFS) rates of the two cohorts were not different (OS: 73.0% vs. 71.9%, p=0.545; PFS: 69.5% vs. 68.8%, p=0.616). However, in patients aged ≥75 years, the 4-year OS and PFS rates were higher in this cohort than in the PROCESS cohort (OS: 49.6% vs. 33.7%, p=0.032; PFS: 44.2% vs. 30.3% p=0.047). Conclusion Pegfilgrastim prophylaxis is effective in the prevention of FN and infection-related death in DLBCL patients receiving R-CHOP, and it also improves OS in patients aged ≥75 years.

Background: This study aimed to evaluate the dose-dependent effects of smoking on risk of diabetes among those quitting smoking. Methods: We analyzed clinical data from a total of 5,198,792 individuals age 20 years or older who received health care check-up arranged by the national insurance program of Korea between 2009 and 2016 using the Korean National Health Insurance Service database. Cumulative smoking was estimated by pack-years. Smokers were classified into four categories according to the amount of smoking: light smokers (0.025 to 5 smoking pack-years), medium smokers (5 to 14 smoking pack-years), heavy smokers (14 to 26 smoking pack-years), and extreme smokers (more than 26 smoking pack-years). Results: During the study period, 164,335 individuals (3.2% of the total population) developed diabetes. Compared to sustained smokers, the risk of diabetes was significantly reduced in both quitters (hazard ratio [HR], 0.858; 95% confidence interval [CI], 0.838 to 0.878) and nonsmokers (HR, 0.616; 95% CI, 0.606 to 0.625) after adjustment for multiple risk factors. The risk of diabetes gradually increased with amount of smoking in both quitters and current smokers. The risk of diabetes in heavy (HR, 1.119; 95% CI, 1.057 to 1.185) and extreme smokers (HR, 1.348; 95% CI, 1.275 to 1.425) among quitters was much higher compared to light smokers among current smokers. Conclusion Smoking cessation was effective in reducing the risk of diabetes regardless of weight change. However, there was a potential dose-dependent association between smoking amount and the development of diabetes. Diabetes risk still remained in heavy and extreme smokers even after smoking cessation.