Trends of antimicrobial susceptibilities and multidrug-resistant colonization rate in patients transferred from long-term care facilities during 2017-2022: a cross-sectional study.

BACKGROUND: With the global increase in the older population, the proportion of those receiving care in long-term care facilities (LTCFs) has also been increasing. We assessed the epidemiology, antibiotic susceptibility, and colonization status of drug-resistant organisms in patients transferred from LTCFs. METHODS: We retrospectively reviewed the medical records of patients transferred from LTCFs between 2017 and 2022. The reasons for admission, antimicrobial susceptibility, and colonization rates of carbapenem-resistant Enterobacterales (CRE), methicillin-resistant Staphylococcus aureus (MRSA), and carbapenem-resistant Acinetobacter baumannii (CRAB) were recorded. We analyzed the susceptibility and colonization rates by year to identify trends. RESULTS: Of the 936 patients transferred from LTCFs, 54.3% were admitted to the intensive care unit and 12.5% died. The most common reason for admission was infection (n = 573, 61.2%), followed by gastrointestinal bleeding (n = 67, 7.2%) and cerebrovascular disorder (n = 65, 6.9%). A total of 452 Enterobacterales strains were isolated, and their susceptibility rates to ciprofloxacin and cefotaxime were 33.3% and 35.6%, respectively. A total of 54.9% were extended-spectrum beta-lactamase-producing strains, and 4.9% of them were carbapenem-resistant, both of which showed an increasing trend (P = 0.024 and P < 0.001, respectively). The prevalence rates of CRE, CRAB, and MRSA colonization were 9.2%, 7.1%, and 23.1%, respectively. CRE colonization showed a significant increase (P < 0.001), with carbapenemase-producing Enterobacterales accounting for 75.9% of cases. CONCLUSIONS: Patients transferred from LTCFs are primarily affected by infections and exhibit high resistance rates. The increasing trend in CRE colonization rates each year highlights the need for the implementation of rigorous infection control measures for effective management.

Design of a Bioinspired Robust Three-Dimensional Cross-Linked Polymer Binder for High-Performance Li-Ion Battery Applications.

Si has the highest theoretical capacity (4200 mA h g-1) among conventional anode materials, such as graphite (372 mA h g-1), but its large volume expansion leads to deterioration of the battery performance. To overcome this problem (issue), we investigated the use of polysaccharide-based 3D cross-linked network binders for Si anodes, in which the polysaccharide formed an effective 3D cross-linked network around Si particles via cross-linking of polysaccharide with citric acid (CA). Sodium alginate (SA), a natural polysaccharide extracted from brown algae, is a suitable binder material for Si anodes because its abundant hydroxyl (-OH) and carboxyl (-COOH) groups form hydrogen and covalent bonds with the -OH groups present on the Si surface. We found that CA-cross-linked (CA-SA) could effectively prevent the volume expansion of Si anodes through the formation of 3D cross-linked network structures. In addition, the CA-SA binders provide enhanced adhesion strength, enabling the fabrication of more robust electrodes than those prepared using binders with linear structures ("linear binders"). In particular, the fabricated Si-based electrode (high mass loading of 1.5 mg cm-2) with CA-SA binder exhibited outstanding areal capacity (∼2.7 mA h cm-2) and excellent cycle retention (∼100% after 100 cycles).

Comparison of Cryopreservation Media for Mesenchymal Stem Cell Spheroids.

Multipotent mesenchymal stromal/stem cell (MSC) spheroids generated in three-dimensional culture are of considerable interest as a novel therapeutic tool for regenerative medicine. However, the lack of reliable methods for storing MSC spheroids represents a significant roadblock to their successful use in the clinic. An ideal storage medium for MSC spheroids should function as both a vehicle for delivery and a cryoprotectant during storage of spheroids for use at a later time. In this study, we compared the outcomes after subjecting MSC spheroids to a freeze/thaw cycle in three Good Manufacturing Practices-grade cryopreservation media, CryoStor10 (CS10), Stem-Cellbanker (SCB), and Recovery Cell Culture Freezing Media (RFM) or conventional freezing medium (CM) (CM, Dulbecco's modified Eagle's medium containing 20% fetal bovine serum and 10% dimethyl sulfoxide) as a control for 2 months. The endpoints tested were viability, morphology, and expression of stem cell markers and other relevant genes. The results of LIVE/DEAD™ assays and annexin V/propidium iodide staining suggested that viability was relatively higher after one freeze/thaw cycle in CS10 or SCB than after freeze/thaw in CM or RFM. Furthermore, the relative "stemness" and expression of MSC markers were similar with or without freeze/thaw in CS10. Scanning electron microscopy also indicated that the surface morphology of MSC spheroids was well preserved after cryopreservation in CS10. Thus, even though it was tested for a short-term period, we suggest that CS10, which has been approved for clinical use by the U.S. Food and Drug Association, is a promising cryopreservation medium that would facilitate the development of MSC spheroids for future clinical use.

Effectiveness and Adverse Events of Nirmatrelvir/Ritonavir Versus Molnupiravir for COVID-19 in Outpatient Setting: Multicenter Prospective Observational Study.

BACKGROUND: In this study, we aimed to compare the effectiveness and adverse reactions of nirmatrelvir/ritonavir and molnupiravir in high-risk outpatients with coronavirus disease 2019 (COVID-19). METHODS: This multicenter prospective observational study evaluated the rate of hospitalization, death, and adverse events within 28 days of oral antiviral agent prescription (molnupiravir, n = 240; nirmatrelvir/ritonavir, n = 240) to 480 nonhospitalized adult patients with COVID-19 from August 2, 2022 to March 31, 2023. RESULTS: Patients receiving molnupiravir had a higher prevalence of comorbidities (85.8% vs. 70.4%; P < 0.001) and a higher Charlson comorbidity index (2.8 ± 1.4 vs. 2.5 ± 1.5; P = 0.009) than those receiving nirmatrelvir/ritonavir. Three patients required hospitalization (nirmatrelvir/ritonavir group, n = 1 [0.4%]; molnupiravir group, n = 2 [0.8%]; P = 1.000). Nirmatrelvir/ritonavir was associated with a higher risk of adverse events than molnupiravir (odds ratio [OR], 1.96; 95% confidence interval [CI], 1.27-3.03), especially for patients aged 65 years and older (OR, 3.04; 95% CI, 1.71-5.39). The severity of adverse events in both groups was mild to moderate and improved after discontinuation of medication. In the molnupiravir group, age ≥ 65 years (OR, 0.43 95% CI, 0.22-0.86) and appropriate vaccination (OR, 0.37; 95% CI, 0.15-0.91) reduced the occurrence of adverse events. CONCLUSION: The rates of hospitalization and death were low and not significantly different between high-risk patients who received either nirmatrelvir/ritonavir or molnupiravir. Although adverse events were more frequent with nirmatrelvir/ritonavir than with molnupiravir, none were severe. Nirmatrelvir/ritonavir can be safely used to treat COVID-19, while molnupiravir could be considered as an alternative treatment option for high-risk groups.

Self-assembled adipose-derived mesenchymal stem cells as an extracellular matrix component- and growth factor-enriched filler.

The clinical application of mesenchymal stem cells (MSCs) is attracting attention due to their excellent safety, convenient acquisition, multipotency, and trophic activity. The clinical effectiveness of transplanted MSCs is well-known in regenerative and immunomodulatory medicine, but there is a demand for their improved viability and regenerative function after transplantation. In this study, we isolated MSCs from adipose tissue from three human donors and generated uniformly sized MSC spheroids (∼100 µm in diameter) called microblocks (MiBs) for dermal reconstitution. The viability and MSC marker expression of MSCs in MiBs were similar to those of monolayer MSCs. Compared with monolayer MSCs, MiBs produced more extracellular matrix (ECM) components, including type I collagen, fibronectin, and hyaluronic acid, and growth factors such as vascular endothelial growth factor and hepatocyte growth factor. Subcutaneously injected MiBs showed skin volume retaining capacity in mice. These results indicate that MiBs could be applied as regenerative medicine for skin conditions such as atrophic scar by having high ECM and bioactive factor expression.

Effect of different cooking method on vitamin E and K content and true retention of legumes and vegetables commonly consumed in Korea.

This study investigated the effect of cooking method on the content and true retention of vitamin E and K in legumes and vegetables, which are commonly consumed in Korea. Among eight isomers of vitamin E, α- and γ-tocopherol were detected at 0.44-1.03 and 2.05-2.11 mg/100 g, respectively, in legumes including chick pea, kidney bean, lentil, pea, and sword bean and they were decreased after boiling. Phylloquinone (vitamin K1) was present at a range of 31.33 to 91.34 µg/100 g in legumes and true retention was reduced after boiling. In 21 kinds of vegetables, α-tocopherol and phylloquinone were present at 0.14-1.85 mg/100 g and 34.55-510.83 µg/100 g, respectively. α-Tocopherol and phylloquinone increased in most vegetables after cooking via blanching, boiling, steaming, and grilling. This study revealed that cooking changed vitamin E and K contents of legumes and vegetables and the changes were dependent on the type of food and cooking method. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-022-01206-9.

Validation of the AOAC method for analyzing fatty acids in meat by-products for the Korean Food Composition Database.

The constituents of meat and meat by-product are susceptible to degradation processes, especially, the control of oxidative processes is critical. The main factors that influence their lipid oxidation are fat content and fatty acid composition. The aim of this study was to validate AOAC method 996.06 for analysis of fatty acid in meat by-products and to provide their accurate, precise, and reliable information in the Korean Food Composition Database. A total of 19 fatty acids were identified. The head, small intestine, stomach, and heart of pigs and the feet of chickens contained higher contents of total fatty acids, whereas the blood of cow had the lowest content. In particular, meat by-products other than the liver, blood, and stomach of cows and the stomach and small intestine of pigs contained higher contents of unsaturated fatty acids. Their main fatty acids were oleic acid, palmitic acid, linoleic acid, and stearic acid. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-022-01223-8.

Evaluation of Barley and Wheat Germplasm for Resistance to Head Blight and Mycotoxin Production by Fusarium asiaticum and F. graminearum.

Fusarium head blight (FHB) is one of the most serious diseases in barley and wheat, as it is usually accompanied by the production of harmful mycotoxins in the grains. To identify FHB-resistant breeding resources, we evaluated 60 elite germplasm accessions of barley (24) and wheat (36) for FHB and mycotoxin accumulation. Assessments were performed in a greenhouse and five heads per accession were inoculated with both Fusarium asiaticum (Fa73, nivalenol producer) and F. graminearum (Fg39, deoxynivalenol producer) strains. While the accessions varied in disease severity and mycotoxin production, four wheat and one barley showed <20% FHB severity repeatedly by both strains. Mycotoxin levels in these accessions ranged up to 3.9 mg/kg. FHB severity was generally higher in barley than in wheat, and Fa73 was more aggressive in both crops than Fg39. Fg39 itself, however, was more aggressive toward wheat and produced more mycotoxin in wheat than in barley. FHB severity by Fa73 and Fg39 were moderately correlated in both crops (r = 0.57/0.60 in barley and 0.42/0.58 in wheat). FHB severity and toxin production were also correlated in both crops, with a stronger correlation for Fa73 (r = 0.42/0.82 in barley, 0.70 in wheat) than for Fg39.

Nirmatrelvir/Ritonavir Prescription Rate and Outcomes in Coronavirus Disease 2019: A Single Center Study.

BACKGROUND: Nirmatrelvir/ritonavir was Korea's first oral antiviral agent to treat coronavirus disease 2019 (COVID-19). We analyzed the nirmatrelvir/ritonavir prescription rate and treatment outcomes in treatment-eligible patients with COVID-19 receiving home-based care. MATERIALS AND METHODS: We retrospectively collected data of patients with COVID-19-eligible for nirmatrelvir/ritonavir treatment from January 14, 2022, to February 15, 2022. We analyzed the prescription rate of nirmatrelvir/ritonavir, the reasons for non-prescription, and patient outcomes. RESULTS: A total of 414 patients were included, of whom 44.2% were male, and the mean age was 64.6 (standard deviation [SD] = 8.5). Approximately 73.2% (n = 303) of patients were not prescribed nirmatrelvir/ritonavir. More than fourth-fifths of the patients refused nirmatrelvir/ritonavir treatment (n = 262, 86.5%). The mean symptom duration was significantly shorter in the prescription group (5.2 days [SD = 2.3] vs. 4.4 days [SD = 1.9], P = 0.001). A total of 6 (1.4%) patients were hospitalized, and none of the patients who received nirmatrelvir/ritonavir required admission. Among the patients prescribed nirmatrelvir/ritonavir (n = 111), 17 (15.3%) patients experienced side effects, and 5 (4.5%) patients discontinued nirmatrelvir/ritonavir due to side effects. CONCLUSION: The nirmatrelvir/ritonavir prescription rate was low, with more than fourth-fifths of non-prescriptions being due to patient refusal. Symptom resolution was faster, and no life-threatening side effects were reported. Accurate information about drug safety must be provided to patients to make informed decisions regarding nirmatrelvir/ritonavir treatment.

Protocol and clinical characteristics of patients under 'at-home care' for COVID-19 in South Korea: a retrospective cohort study.

OBJECTIVE: As the number of patients with COVID-19 increased, at-home care was introduced for the first time in South Korea. This study aimed to analyse the characteristics and outcomes of patients who were treated under at-home care. DESIGN, SETTING AND PARTICIPANTS: This retrospective cohort study targeted patients under at-home care for COVID-19 in Yeongdeungpo-gu in Seoul, Korea, from 18 October 2021 to 12 December 2021. The public health centre selected eligible patients for at-home care and registered with our institution. Nurses monitored patients, and doctors decided to transfer healthcare facilities and release the quarantined patients according to their symptoms. OUTCOME MEASURES: Patient characteristics during the course of at-home care. RESULTS: A total of 1422 patients were enrolled and 9574 patient-days were managed. Most patients were aged ≥60 years (22.7% (n=323)), and 82.8% did not have underlying conditions. The median length of care for patients was 8 days (IQR: 5-10 days). During the study period, 986 (69.3%) patients were released from quarantine, 82 (5.8%) patients were transferred to facilities and 354 (24.9%) patients were still under at-home care at the end of the study period. The most common cause of transfer was sustained fever (n=30; 36.6%), followed by dyspnoea and desaturation (n=17; 20.7%). Factors associated with transfer were diabetes (OR: 3.591, 95% CI 1.488 to 8.665, p=0.004), pregnancy (OR: 5.839, 95% CI 1.035 to 32.935, p=0.046) and being presymptomatic at diagnosis (OR: 4.015, 95% CI 1.559 to 10.337, p=0.004). CONCLUSIONS: There were no specific problems related to patient safety when operating at-home care. Patients with risk factors, such as diabetes, were more likely to be transferred to healthcare facilities. For safe at-home care, it is necessary to prepare for an appropriate response to the emergency.

Thirty-Day Mortality Rates in Patients with Extended-Spectrum ß-Lactamase-Producing Enterobacterales Bacteremia Receiving Ertapenem versus Other Carbapenems.

Ertapenem is one of the carbapenems recommended for treating extended-spectrum ß-lactamase (ESBL)-producing Enterobacterales. However, efficacy data are limited. We compared 30-day mortality rates for patients receiving ertapenem and other carbapenems for treatment of ESBL-producing Enterobacterales bacteremia. A multicenter, retrospective study was performed from January 2013 to December 2020 at three hospitals. Patients who received only members of one group of carbapenems (group 1 or group 2) throughout their treatment for ESBL-producing Escherichia coli or Klebsiella pneumoniae bacteremia were enrolled. To compare 30-day all-cause mortality rates in the two groups, propensity score matching was used to control for selection bias. Subgroup analyses were performed for several subgroups. Secondary outcomes included Clostridioides difficile infection (CDI) and the emergence of multidrug-resistant Gram-negative bacteria within 90 days after initiation of carbapenem treatment. One-to-one propensity score matching yielded 162 pairs of patients from the total of 603 patients included. There was no difference in 30-day mortality rates between ertapenem and the other carbapenems in adjusted analyses (hazard ratio, 0.60 [95% confidence interval [CI], 0.29 to 1.22]) of the propensity score-matched cohorts. A similar result was obtained in a subgroup analysis of patients who suffered severe sepsis or septic shock and those who did not (P = 0.54 for interaction). Emergence of CDI (odds ratio [OR], 0.99 [95% CI, 0.44 to 2.20]) and carbapenem-resistant Enterobacterales (OR, 1.31 [95% CI, 0.51 to 3.53]) did not differ between the two groups. Our study suggests that the efficacy of ertapenem may be comparable to that of the other carbapenems in treatment of ESBL-producing E. coli and K. pneumoniae bacteremia.

Preparation and Electrochemical Characterization of Si@C Nanoparticles as an Anode Material for Lithium-Ion Batteries via Solvent-Assisted Wet Coating Process.

Silicon-based electrodes are widely recognized as promising anodes for high-energy-density lithium-ion batteries (LIBs). Silicon is a representative anode material for next-generation LIBs due to its advantages of being an abundant resource and having a high theoretical capacity and a low electrochemical reduction potential. However, its huge volume change during the charge-discharge process and low electrical conductivity can be critical problems in its utilization as a practical anode material. In this study, we solved the problem of the large volume expansion of silicon anodes by using the carbon coating method with a low-cost phenolic resin that can be used to obtain high-performance LIBs. The surrounding carbon layers on the silicon surface were well made from a phenolic resin via a solvent-assisted wet coating process followed by carbonization. Consequently, the electrochemical performance of the carbon-coated silicon anode achieved a high specific capacity (3092 mA h g-1) and excellent capacity retention (~100% capacity retention after 50 cycles and even 64% capacity retention after 100 cycles at 0.05 C). This work provides a simple but effective strategy for the improvement of silicon-based anodes for high-performance LIBs.

Sensitivity to tumor development by TALEN-mediated Trp53 mutant genes in the susceptible FVB/N mice and the resistance C57BL/6 mice.

BACKGROUND: This study was undertaken to compare the sensitivities of mice strains during tumor induction by transcription activator-like effector nucleases (TALEN)-mediated Trp53 mutant gene. Alterations of their tumorigenic phenotypes including survival rate, tumor formation and tumor spectrum, were assessed in FVB/N-Trp53em2Hwl/Korl and C57BL/6-Trp53em1Hwl/Korl knockout (KO) mice over 16 weeks. RESULTS: Most of the physiological phenotypes factors were observed to be higher in FVB/N-Trp53em2Hwl/Korl KO mice than C57BL/6-Trp53em1Hwl/Korl KO mice, although there were significant differences in the body weight, immune organ weight, number of red blood cells, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), platelet count (PLT), total bilirubin (Bil-T) and glucose (Glu) levels in the KO mice relative to the wild type (WT) mice. Furthermore, numerous solid tumors were also observed in various regions of the surface skin of FVB/N-Trp53em2Hwl/Korl KO mice, but were not detected in C57BL/6-Trp53em1Hwl/Korl KO mice. The most frequently observed tumor in both the Trp53 KO mice was malignant lymphoma, while soft tissue teratomas and hemangiosarcomas were only detected in the FVB/N-Trp53em2Hwl/Korl KO mice. CONCLUSIONS: Our results indicate that the spectrum and incidence of tumors induced by the TALEN-mediated Trp53 mutant gene is greater in FVB/N-Trp53em2Hwl/Korl KO mice than C57BL/6-Trp53em1Hwl/Korl KO mice over 16 weeks.

Comparison of the Results of Five SARS-CoV-2 Antibody Assays before and after the First and Second ChAdOx1 nCoV-19 Vaccinations among Health Care Workers: a Prospective Multicenter Study.

Reliable results for serological positivity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody after the second dose of AstraZeneca (AZ) vaccination are important to estimate the real efficacy of vaccination. We evaluated positivity rates and changes in semiquantitative antibody titers before and after the first and second ChAdOx1 nCoV-19 vaccinations using five SARS-CoV-2 antibody assays, including two surrogate virus neutralization tests. A total of 674 serum samples were obtained from 228 participants during three blood sampling periods. A questionnaire on symptoms, severity, and adverse reaction duration was completed by participants after the second vaccination. The overall positive rates for all assays were 0.0 to 0.9% before vaccination, 66.2 to 92.5% after the first vaccination, and 98.2 to 100.0% after the second vaccination. Median antibody titers in five assays after the second dose of vaccination were increased compared to those after the first dose (106.4-fold increase for Roche total antibody, 3.6-fold for Abbott IgG, 3.6-fold for Siemens, 1.2-fold for SD Biosensor V1 neutralizing antibody, and 2.2-fold for GenScript neutralizing antibody). Adverse reactions were reduced after the second dose in 89.9% of participants compared to after the first dose. Overall, the second vaccination led to almost 100% positivity rates based on these SARS-CoV-2 antibody assays. The results should be interpreted with caution, considering the characteristics of the applied assays. Our findings could inform decisions regarding vaccination and the use of immunoassays, thus contributing to SARS-CoV-2 pandemic control.

Antibiotic Resistance Patterns of Enterobacteriaceae Isolated from Patients with Healthcare-Associated Infections.

BACKGROUND: There have been recent proposals to categorize healthcare-associated infections (HCAIs) separately from community-acquired infections (CAIs). The aim of this study was to compare the antibiotic resistance of pathogens causing CAIs, HCAIs, and hospital-acquired infections (HAIs) in Korea, and to investigate the need for different empirical antibiotics therapy for CAIs and HCAIs. MATERIALS AND METHODS: This prospective study was conducted in a university hospital between March and December 2019. Inpatients who underwent a bacterial culture within 2 days of hospitalization, with a Enterobacteriaceae strain identified at the infection site and available antibiotic susceptibility results, were included in the analysis. Infections were classified as CAIs, HCAIs or HAIs, depending on the source. RESULTS: Of the 146 patients included in the analysis, the prevalence of fluoroquinolone-resistant Enterobacteriaceae was 18.8%, 38.5%, and 55.0%; the prevalence of pathogens showing third-generation cephalosporins resistance was 8.3%, 50.0%, and 60.0%; and the prevalence of pathogens showing piperacillin-tazobactam resistance was 8.3%, 7.7%, 15.0% in the CAIs, HCAIs, and HAIs groups, respectively. The prevalence of extended-spectrum beta-lactamase-positive pathogens was 6.3%, 47.3%, and 55.0% in the CAIs, HCAIs, and HAIs group, respectively, with no significant difference between the HCAIs and HAIs groups. Resistance patterns of the HCAIs group more closely resembled those of the HAIs group than those of the CAIs group. CONCLUSION: The pathogens isolated from patients with HCAIs showed resistance patterns that were more similar to those of patients with HAIs than those with CAIs. Thus, CAIs and HCAIs should be distinguished from each other when selecting antibiotic agents.

Comparing Results of Five SARS-CoV-2 Antibody Assays Before and After the First Dose of ChAdOx1 nCoV-19 Vaccine among Health Care Workers.

Reliable results regarding serologic positivity for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody before and after AstraZeneca (AZ) vaccination are essential for estimating the efficacy of vaccination. We assessed positivity rates and associated factors using five SARS-CoV-2 antibody assays. A total of 228 paired serum samples (456 samples) were obtained from 228 participants. After baseline sampling, the second sampling was conducted between 11 and 28 days after the first dose of the AZ vaccine. Sera were tested using five SARS-CoV-2 antibody assays, including two surrogate virus neutralization tests. A questionnaire on the symptoms, severity, and duration of adverse reactions was completed by all participants. The overall positivity rates for SARS-CoV-2 antibody were 84.6% for the Roche assay, 92.5% for the Abbott assay, 75.4% for the Siemens assay, 90.7% for the SD Biosensor assay, and 66.2% for the GenScript assay after the first dose of the AZ vaccine. The positivity rates and antibody titers of sera obtained between 21 and 28 days were significantly higher than those obtained between 11 and 20 days in all five assays. More-severe adverse reactions and longer durations of adverse reactions were related to higher SARS-CoV-2 antibody levels. The agreements and correlations among the assays applied were substantial (к, 0.73 to 0.95) and strong (ρ, 0.83 to 0.91). A single dose of the AZ vaccine led to high positivity rates based on the five assays. Days after vaccination and adverse reactions could help estimate serologic conversion rates. The results should be interpreted cautiously considering the assays and cutoffs applied. Our findings could inform decisions regarding vaccination and laboratory settings and could thus contribute to the control of the spread of SARS-CoV-2 infection.

Fit Test for N95 Filtering Facepiece Respirators and KF94 Masks for Healthcare Workers: a Prospective Single-center Simulation Study.

BACKGROUND: For protection against coronavirus disease 2019 (COVID-19), the Korean government recommended the KF94 mask or that a mask at the same level as the KF94 should be worn when contacting a patient with COVID-19. Furthermore, adequately fitted N95 respirators and KF94 masks are essential. We investigated the fit tests to determine whether healthcare workers had adequate protection with N95 respirators and KF94 masks. METHODS: In this prospective single-center simulation study, five N95 respirators (two made in the USA by 3M and three made in Korea) and six KF94 masks, the Korean standard medical masks, were tested. The fit factor (FF) and leakage rate were evaluated using a two-fit test device. Adequate protection (defined as FF ≥ 100 or leakage rate ≤ 5) rates were compared between N95 respirators and KF94 masks, and between made in Korea and the 3M N95 respirators. For KF94 masks, adequate protection rates were compared before and after ear strap fixation. RESULTS: Overall, 30 participants were enrolled, and 330 fit tests were performed for FF and leakage rate. Adequate protection rates of all tested N95 respirators and KF94 masks were 22.7% (n = 75) by FF and 20.6% (n = 68) by leakage rate. N95 respirators showed a significantly higher adequate protection rate than KF94 masks for FF (48.7% vs. 1.1%, P < 0.001) and leakage rate (42.0% vs. 2.8%, P < 0.001). Adequate protection rate of 3M-made N95 respirators was significantly higher than that of those made in Korea (83.3% vs. 25.6% in FF, P < 0.001; 73.3% vs. 21.1% in leakage rate, P < 0.001). In KF94 masks, after fixation of ear strap with a hook, adequate protection rate improved significantly (1.1% vs. 12.8% in FF, P < 0.001; 2.8% vs. 11.1%, P < 0.001). CONCLUSION: Although adequate protection rate of N95 respirators was higher than that of KF94 masks, N95 respirator protection rate was not optimum. Thus, it is necessary to minimize exposure to risk by selecting an appropriate mask or respirator that adequately fits each person, and by wearing respirators or masks appropriately, before contacting the patients. With their superior protection rate, wearing N95 respirators is recommended instead of KF94 masks, especially when performing aerosol-generating procedures.

Effect of Application Amounts on In Vitro Dermal Absorption Test Using Caffeine and Testosterone.

Dermal absorption of chemicals is a key factor in risk assessment. This study investigated the effects of different amounts of application on dermal absorption and suggested an appropriate application dose for proper dermal absorption. Caffeine and testosterone were chosen as test compounds. An in vitro dermal absorption test was performed using a Franz diffusion cell. Different amounts (5, 10, 25, and 50 mg (or µL)/cm2) of semisolid (cream) and liquid (solution) formulations containing 1% caffeine and 0.1% testosterone were applied to rat and minipig (Micropig®) skins. After 24 h, the concentrations of both compounds remaining on the skin surface and in the stratum corneum, dermis and epidermis, and receptor fluid were determined using LC-MS / MS or HPLC. Dermal absorption of both compounds decreased with increasing amounts of application in both skin types (rat and minipig) and formulations (cream and solution). Especially, dermal absorptions (%) of both compounds at 50 mg (or µL)/cm2 was significantly lower compared to 5 or 10 mg (or µL)/cm2 in both rat and minipig skins. Therefore, a low dose (5 or 10 mg (or µL)/cm2) of the formulation should be applied to obtain conservative dermal absorption.

Metabolomics approach to biomarkers of dry eye disease using 1H-NMR in rats.

Dry eye disease (DED) is a chronic and progressive lesion on the ocular surface and induces symptoms, such as burning sensation, itchy eyes, heavy eyes, tired eyes, dry feeling, facial flushing, and blurred vision. The present study was performed to develop DED biomarkers using metabolomics in a rat model. DED was induced by injecting scopolamine and exposing rats to a dry condition. Scopolamine (12 mg/kg/day for 7 days) was subcutaneously injected to male Sprague-Dawley rats. The rats were placed in dry condition with air-flow and dehumidifier. Tear volume and tear breakup time (TBUT) were measured, and eyes were examined through fluorescein staining to assess DED. Mucosal damage and immune reactions were also determined. Plasma and urinary endogenous metabolites were determined using 1H-NMR analysis. Compared with control tear and TBUT levels were significantly decreased in the DED group whereas corneal damage was significantly increased. The levels of interleukins (IL-6) and IL-1ß significantly elevated in the cornea and lacrimal glands in the DED group. TNF-α was numerically increased but not significantly different between groups. Pattern recognition using principal component analysis (PCA) and orthogonal projections to latent structure-discriminant analysis (OPLS-DA) of the NMR spectra in global profiling revealed different clusters between DED and control groups. Target profiling demonstrated that PCA and OPLS-DA score plots were separated between DED and controls in plasma and urine. Subsequently, 9 plasma metabolites were selected to examine different clustering between groups, and 26 urinary metabolites were also selected. Plasma metabolites showed a non-significant rising tendency in the DED group. Urinary phenylalanine, phenylacetate, pantothenate, glycine, succinate, methanol, valine, propylene glycol, histidine, threonine, lactate, and acetate were significantly different between control and DED rats. These results may contribute to understanding the metabolic regulation that is involved in DED and might be useful for potential biomarkers related to DED in rats.

Seven-Month Analysis of Five SARS-CoV-2 Antibody Assay Results after ChAdOx1 nCoV-19 Vaccination: Significant Decrease in SARS-CoV-2 Antibody Titer.

We investigated the longevity rates of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after a complete ChAdOx1 nCoV-19 vaccination, which are rare and important to estimate their efficacy and establish a vaccination strategy. We assessed the positivity rates and changes of titers before (T0) and at one month (T1), four months (T2), and seven months (T3) after a ChAdOx1 nCoV-19 vaccination using five SARS-CoV-2 antibody assays. A total of 874 serum samples were obtained from 228 (T0 and T1), 218 (T2), and 200 (T3) healthcare workers. The positive rates for all five assays were 0.0-0.9% at T0, 66.2-92.5% at T1, 98.2-100.0% at T2, and 66.0-100.0% at T3. The positive rates at T3 were decreased compared to those at T2. The median antibody titers of all the assays at T3 were significantly decreased compared to those at T2 (860.5 to 232.0 U/mL for Roche total, 1041.5 to 325.5 AU/mL for Abbott IgG, 10.9 to 2.3 index for Siemens IgG, 99.5% to 94.7% for SD Biosensor V1, and 88.5% to 38.2% for GenScript). A third-dose scheme can be considered based on our data generated from five representative assays. Our findings contribute insights into SARS-CoV-2 antibody assays and appropriate vaccination strategies.