BackgroundThe objective of this study was to explore whether individual variations in the concentration of growth factors (GFs) influence the biologic effects of platelet-rich plasma (PRP) on human mesenchymal stem cells (HMSCs).MethodsThe concentrations of 7 representative GFs in activated PRP (aPRP) were measured using ELISA. The effects of PRP on the proliferation and alkaline phosphatase (ALP) activity of HMSCs were examined using several concentrations of aPRP from 3 donors; the relationships between the GF levels and these biologic effects were then evaluated using 10% aPRP from 5 subgroups derived from 39 total donors. HMSCs were cultured in DMEM with the addition of aPRP for 4 or 12 days; then, DNA content and ALP activity were measured.ResultsThe quantity of DNA increased significantly at a 10% concentration of aPRP, but the ALP activity was suppressed at this concentration of aPRP. The GF concentrations varied among donors, and 5 subgroups of characteristic GF release patterns were identified via cluster analysis. DNA levels differed significantly between groups and tended to be higher in groups with higher concentrations of transforming growth factor-beta1 (TGF-β1) and platelet-derived growth factors (PDGFs). DNA quantity was positively correlated with TGF-β1 concentration, and was negatively correlated with donor age. ALP activity was negatively correlated with PDGF-BB concentration.ConclusionsThe varying GF concentrations may result in different biologic effects; thus, individual differences in GF levels should be considered for reliable interpretation of the biologic functions and standardized application of PRP.

Introduction: We experienced an emergency room (ER) shutdown related to an accidental exposure to a patient with COVID-19 who had not been isolated. To prevent in-hospital transmission of the disease, we subsequently isolated patients with suspected symptoms, relevant radiographic findings, or epidemiology. The SARS-CoV-2 reverse-transcriptase polymerase chain reaction was performed in most patients requiring hospitalization. Universal mask policy and comprehensive use of personal protective equipment (PPE) were implemented. Materials and Methods: The effect of the interventions was analyzed in a 635-bed, tertiary-care hospital in Daegu, South Korea. Results: From the pre-shutdown (February 10 to 25) to the post-shutdown (February 28 to March 16, 2020) period, the mean hourly turnaround time (23:31±6:43 versus 9:27±3:41, P<0.001) was shortened, which increased the proportions of the patients tested (5.8% [N=1,037] versus 64.6% [N=690], P<0.001) and the average number of tests per day (3.8±4.3 versus 24.7±5.0, P<0.001). All 23 patients with COVID-19 in the post-shutdown period were isolated in the ER without any problematic accidental exposure or in-hospital transmission. From the pre- to the post-shutdown period, the median duration of stay in the ER among hospitalized patients (4:30 hr [2:17-9:48] versus 14:33 hr (6:55-24:50), P<0.001), rates of intensive care unit admissions (1.4% versus 2.9%, P=0.023), and mortality (0.9% versus 3.0%, P=0.001) increased. Conclusions: Problematic accidental exposure and in-hospital transmission of COVID-19 can be successfully prevented through active isolation and surveillance policy and comprehensive PPE use despite longer ER stays and the presence of more severely ill patients during an explosive COVID-19 outbreak.

Background: Laboratory parameter abnormalities are commonly observed in COVID-19 patients; however, their clinical significance remains controversial. We assessed the prevalence, characteristics, and clinical impact of laboratory parameters in COVID-19 patients hospitalized in Daegu, Korea. Methods:We investigated the clinical and laboratory parameters of 1,952 COVID-19 patients on admission in nine hospitals in Daegu, Korea. The average patient age was 58.1 years, and 700 (35.9%) patients were men. The patients were classified into mild (N=1,612), moderate (N = 294), and severe (N = 46) disease groups based on clinical severity scores. We used chi-square test, multiple comparison analysis, and multinomial logistic regression to evaluate the correlation between laboratory parameters and disease severity.Results: Laboratory parameters on admission in the three disease groups were significantly different in terms of hematologic (Hb, Hct, white blood cell count, lymphocyte%, and platelet count), coagulation (prothrombin time and activated partial thromboplastin time), biochemical (albumin, aspartate aminotransferase, alanine aminotransferase, lactate, blood urea nitrogen, creatinine, and electrolytes), inflammatory (C-reactive protein and procalcitonin), cardiac (creatinine kinase MB isoenzyme and troponin I), and molecular virologic (Ct value of SARS-CoV-2 RdRP gene) parameters. Relative lymphopenia, prothrombin time prolongation, and hypoalbuminemia were significant indicators of CO-VID-19 severity. Patients with both hypoalbuminemia and lymphopenia had a higher risk of severe COVID-19.Conclusions: Laboratory parameter abnormalities on admission are common, are significantly associated with clinical severity, and can serve as independent predictors of CO-VID-19 severity. Monitoring the laboratory parameters, including albumin and lymphocyte count, is crucial for timely treatment of COVID-19.

Roseomonas is a genus of pink-pigmented nonfermentative bacilli. These slow-growing, gram-negative cocobacilli form pink-colored colonies on sheep blood agar. They differ from other pink-pigmented nonfermenters, including Methylobacterium, in morphology, biochemical characteristics, and DNA sequence. Roseomonas strains are rarely isolated in clinical laboratories; therefore, we report two cases in order to improve our ability to identify these pathogens. We isolated two strains of Roseomonas mucosa from the venous blood cultures of two patients, an 84-yr-old woman with common bile duct obstruction and a 17-yr-old male with acute myeloid leukemia who had an indwelling central-venous catheter for chemotherapy. The isolated strains were confirmed as R. mucosa by 16S rRNA sequencing.

Clostridium difficile is one of the main etiological agents causing antibiotic-associated diarrhea. This study investigated the genetic diversity of 70 toxigenic C. difficile isolates from two Korean hospitals by employing toxinotyping, ribotyping, multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE). Toxin gene amplification resulted in 68 A⁺B⁺ and two A-B+ isolates. Most isolates (95.7–100%) were susceptible to daptomycin, metronidazole, and vancomycin. Seventy C. difficile isolates were classified into five toxinotypes, 19 ribotypes, 16 sequence types (STs), and 33 arbitrary pulsotypes. All C. difficile isolates of ribotype 018 (n = 38) were classified into ST17, which was the most prevalent ST in both hospitals. However, C. difficile isolates of ST17 (ribotype 018) exhibited pulsotypes that differed by hospital. ST2 (ribotype 014/020), 8 (ribotypes 002), 17 (ribotype 018), and 35 (ribotypes 015) were detected in both hospitals, whereas other STs were unique to each hospital. Statistical comparison of the different typing methods revealed that ribotyping and PFGE were highly predictive of STs. In conclusion, our epidemiological study indicates that C. difficile infections in both hospitals are associated with the persistence of endemic clones coupled with the emergence of many unique clones. A combination of MLST with PFGE or ribotyping could be useful for monitoring epidemic C. difficile strains and the emergence of new clones in hospitals.