Effectiveness of Heterologous COVID-19 Vaccine Booster in Korean Elderly Population, 2022

We conducted a cohort study to assess vaccine effectiveness (VE) of coronavirus disease 2019 vaccine combinations on severe acute respirator y syndrome coronavirus 2 critical infection and death among elderly population in Korea. From Januar y to August 2022, VE against death for 4 doses mRNA recipients was 96.1%, whereas 1-dose viral vector + 3-dose mRNA recipients had VE of 90.8%.

The Lived Experiences of Patient’s Families with the Intensive Care Unit Diary / 중환자간호학회지

Purpose@#: Intensive care unit (ICU) diaries have been implemented across the international ICU community. This study aimed to comprehend the meaning and nature of the lived experience of patients’ families using the ICU diary in Korea. @*Methods@#: This qualitative study adopted van Manen’s hermeneutic phenomenology. The participants comprised eight women and two men who were the family members of patients in the ICU for more than three days. Data were collected using in-depth interviews and observation from July 2018 to January 2019. @*Results@#: Patients’ families who experienced the ICU diary recognized it with six beings according to time: a good idea, forgotten stuff, burdensome work, touching service, my stuff, and a thing in the memory. The ICU diary had three essential meanings for the families: communication, solace and hope, and a record of life. These findings were rearranged according to van Manen’s fundamental existential, and the lived things and lived others were remarkably confirmed. @*Conclusion@#: Patients’ families experienced various ICU diary forms over time and recognized an ICU diary as a means of communication. Therefore, the ICU diary is expected to be used as an intervention between families and healthcare providers in the ICU to support mutual communication.

Policy Analysis for Implementing Neuroethics in Korea’s Brain Research Promotion Act

In 1998, Korea implemented the Brain Research Promotion Act (BRPA), a law to revamp the field of neuroscience at the national level. However, despite numerous revisions including the definition and classification of neuroscience and the national plans for the training and education systems, the governance for neuroethics has not been integrated into the Act. The ethical issues raised by neuroscience and neurotechnology remain unchallenged, especially given the focus on the industrial purpose of the technology. In the current study, we analyzed the BRPA revision process by using Kingdon’s Multiple Streams Framework to determine the problems faced by the process. We propose a new strategy, including neuroethics governance and a national committee, to promote interdisciplinary neuroscience research and strengthen neuroethics in Korea.

Unbalanced Redox With Autophagy in Cardiovascular Disease

Precise redox balance is essential for the optimum health and physiological function of the human body. Furthermore, an unbalanced redox state is widely believed to be part of numerous diseases, ultimately resulting in death. In this review, we discuss the relationship between redox balance and cardiovascular disease (CVD). In various animal models, excessive oxidative stress has been associated with increased atherosclerotic plaque formation, which is linked to the inflammation status of several cell types. However, various antioxidants can defend against reactive oxidative stress, which is associated with an increased risk of CVD and mortality. The different cardiovascular effects of these antioxidants are presumably due to alterations in the multiple pathways that have been mechanistically linked to accelerated atherosclerotic plaque formation, macrophage activation, and endothelial dysfunction in animal models of CVD, as well as in in vitro cell culture systems. Autophagy is a regulated cell survival mechanism that removes dysfunctional or damaged cellular organelles and recycles the nutrients for the generation of energy. Furthermore, in response to atherogenic stress, such as the generation of reactive oxygen species, oxidized lipids, and inflammatory signaling between cells, autophagy protects against plaque formation. In this review, we characterize the broad spectrum of oxidative stress that influences CVD, summarize the role of autophagy in the content of redox balance-associated pathways in atherosclerosis, and discuss potential therapeutic approaches to target CVD by stimulating autophagy.

A Randomized, Double-Blind, Placebo-Controlled, Bridging Study to Evaluate the Efficacy and Safety of Vibegron in Treating Korean Patients With Overactive Bladder / 대한배뇨장애요실금학회지

Purpose@#Vibegron, a novel, potent β3 agonist, has been approved for clinical use in overactive bladder (OAB) treatment in Japan and the Unites States. We performed a bridging study to investigate the efficacy and safety of a daily 50-mg vibegron (code name JLP-2002) dose in Korean patients with OAB. @*Methods@#A multicenter, randomized, double-blind, placebo-controlled study was conducted from September 2020 to August 2021. Adult patients with OAB with a symptom duration of more than 6 months entered a 2-week placebo run-in phase. Eligibility was assessed at the end of this phase and selected patients entered a double-blind treatment phase after 1:1 randomization to either the placebo or vibegron (50 mg) group. The study drug was administered once daily for 12 weeks and follow-up visits were scheduled at weeks 4, 8, and 12. The primary endpoint was the change in mean daily micturition at the end of treatment. The secondary endpoints included changes in OAB symptoms (daily micturition, nocturia, urgency, urgency incontinence, and incontinence episodes, and mean voided volume per micturition) and safety. A constrained longitudinal data model was used for statistical analysis. @*Results@#Patients who took daily vibegron had significant improvements over the placebo group in both primary and secondary endpoints, except for daily nocturia episodes. The proportions of patients with normalized micturition and resolution of urgency incontinence and incontinence episodes were significantly higher in vibegron group than in the placebo. Vibegron also improved the patients’ quality of life with higher satisfaction rates. The incidence of adverse events in the vibegron and placebo groups was similar with no serious, unexpected adverse drug reactions. No abnormality in electrocardiographs was observed as well as no significant increase in postvoid residual volume. @*Conclusions@#Once daily vibegron (50 mg) for 12 weeks was effective, safe, and well-tolerated in Korean patients with OAB.

Immunogenicity and Safety of Vaccines against Coronavirus Disease in Actively Treated Patients with Solid Tumors: A Prospective Cohort Study / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#We aimed to assess the humoral response to and reactogenicity of coronavirus disease 2019 (COVID-19) vaccination according to the vaccine type and to analyze factors associated with immunogenicity in actively treated solid cancer patients (CPs). @*Materials and Methods@#Prospective cohorts of CPs, undergoing anticancer treatment, and healthcare workers (HCWs) were established. The participants had no history of previous COVID-19 and received either mRNA-based or adenovirus vector–based (AdV) vaccines as the primary series. Blood samples were collected before the first vaccination and after 2 weeks for each dose vaccination. Spike-specific binding antibodies (bAbs) in all participants and neutralizing antibodies (nAbs) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) wild-type, Delta, and Omicron variants in CPs were analyzed and presented as the geometric mean titer. @*Results@#Age-matched 20 HCWs and 118 CPs were included in the analysis. The bAb seroconversion rate and antibody concentrations after the first vaccination were significantly lower in CPs than in HCWs. After the third vaccination, antibody levels in CPs with a primary series of AdV were comparable to those in HCWs, but nAb titers against the Omicron variant did not quantitatively increase in CPs with AdV vaccine as the primary series. The incidence and severity of adverse reactions post-vaccination were similar between CPs and HCWs. @*Conclusion@#CPs displayed delayed humoral immune response after SARS-CoV-2 vaccination. The booster dose elicited comparable bAb concentrations between CPs and HCWs, regardless of the primary vaccine type. Neutralization against the Omicron variant was not robustly elicited following the booster dose in some CPs, implying the need for additional interventions to protect them from COVID-19.

Multiple Injections of Adipose-Derived Stem Cells Improve Graft Survival in Human-to-Rat Skin Xenotransplantation through Immune Modulation

BACKGROUND@#Adipose-derived stem cells (ADSCs) exert immunomodulatory effects in the treatment of transplant rejection. This study aimed to evaluate the effects of ADSCs on the skin graft survival in a human-to-rat xenograft transplantation model and to compare single and multiple injections of ADSCs. @*METHODS@#Full-thickness human skin xenografts were transplanted into the backs of Sprague–Dawley rats. The rats were injected subcutaneously on postoperative days 0, 3, and 5. The injections were as follows: triple injections of phosphate-buffered saline (PBS group), a single injection of ADSCs and double injections of PBS (ADSC 9 1 group), and triple injections of ADSCs (ADSC 9 3 group). The immunomodulatory effects of ADSCs on human skin xenografts were assessed. @*RESULTS@#Triple injections of ADSCs considerably delayed cell-mediated xenograft rejection compared with the PBS and ADSC 9 1 groups. The vascularization and collagen type 1–3 ratios in the ADSC 9 3 group were significantly higher than those in the other groups. In addition, intragraft infiltration of CD3-, CD4-, CD8-, and CD68-positive cells was reduced in the ADSC 9 3 group. Furthermore, in the ADSC 9 3 group, the expression levels of proinflammatory cytokine interferon-gamma (IFN-c) were decreased and immunosuppressive prostaglandin E synthase (PGES) was increased in the xenograft and lymph node samples. @*CONCLUSION@#This study presented that triple injections of ADSCs appeared to be superior to a single injection in suppressing cell-mediated xenograft rejection. The immunomodulatory effects of ADSCs are associated with the downregulation of IFN-c and upregulation of PGES in skin xenografts and lymph nodes.

Risk factors for transmission in a COVID-19 cluster infection in a high school in the Republic of Korea

Objectives@#This study aimed to examine the scale, characteristics, risk factors, and modes of transmission in a coronavirus disease 2019 (COVID-19) outbreak at a high school in Seoul, Republic of Korea. @*Methods@#An epidemiological survey was conducted of 1,118 confirmed cases and closecontacts from a COVID-19 outbreak at an educational facility starting on May 31, 2021. Indepth interviews, online questionnaires, flow evaluations, and CCTV analyses were used todevise infection prevention measures. Behavioral and spatial risk factors were identified, and statistical significance was tested. @*Results@#Among 3rd-year students, there were 33 confirmed COVID-19 cases (9.6%). Students who used a study room in the annex building showed a statistically significant 4.3-foldelevation in their relative risk for infection compared to those who did not use the study room. Moreover, CCTV facial recognition analysis confirmed that 17.8% of 3rd-year students did not wear masks and had the lowest percentage of mask-wearers by grade. The air epidemiological survey conducted in the study room in the annex, which met the 3 criteria for a closed space, confirmed that there was only 10% natural ventilation due to the poor ventilation system. @*Conclusion@#To prevent and manage the spread of COVID-19 in educational facilities, advance measures that consider the size, operation, and resources of each school are crucial. In addition, various survey methodologies should be used in future studies to quickly analyze a wider range of data that can inform an evidence-based quarantine response.

Innovative Use of Negative Air Ions As an Alternative Therapy for Acne Vulgaris: A Report of Three Cases

Acne vulgaris is a universal skin disease with multifactorial pathogenesis. Although an extensive range of treatment options exist for acne, a substantial number of patients are still struggling for an optimal treatment option due to the side effects or contraindications to the conventional acne treatment. Negative air ions (NAIs) are electrically charged molecules that naturally exist in the atmosphere. Since they are natural component of air, there are no known side effects and contraindications to their application. Furthermore, among the identified benefits of NAIs, certain mechanisms are related to acne pathogenesis, allowing them to be attractive candidates for acne treatment. Here, we describe three patients with acne who showed considerable clinical improvement after NAI therapy. All of the patients had failed to tolerate traditional acne treatment options. In all three cases, considerable improvement was observed in acne severity and the number of total lesions. Based on the three cases and a review of literature underlying the effects of NAIs, we suggest that NAIs may be a safe and effective alternative therapeutic option for acne vulgaris.

Interorganizational Networks for Smoking Prevention and Cessation: A Blockmodeling Approach

Purpose@#This study examined characteristics and patterns of interorganizational networks for smoking prevention and cessation in Korea. @*Methods@#We surveyed two community health centers, ninety-five hospitals or clinics, ninety- two pharmacies, and sixty-five health welfare organizations in two districts of Seoul in 2020. Data on the organizations’ characteristics of smoking cessation and interorganizational activities for information sharing, client referral, and program collaboration were collected and analyzed using network statistics and blockmodeling. @*Results@#Network size was in the order of information sharing, client referral, and program collaboration networks. Network patterns for interorganizational activities on information sharing, client referral, and program collaboration among four organizations were similar between the two districts. Community health centers provided information and received clients from a majority of the organizations. Their interactions were not unidirectional but mutual with other organizations. Pharmacies were involved in information sharing with health welfare organizations and client referrals to hospitals or clinics. Health welfare organizations were primarily connected with the community health centers for client referrals and program collaboration. @*Conclusion@#A community health center is the lead agency in interorganizational activities for smoking prevention and cessation. However, hospitals or clinics, pharmacies, and health welfare organizations also participate in interorganizational networks for smoking prevention and cessation with diverse roles. This study would be evidence for developing future interorganizational networks for smoking prevention and cessation.

Eradication Rate Using a First-line Triple Therapy for Helicobacter pylori Infection in Yeongdong, Gangwon Province, Korea

Background/Aims@#The eradication success rate of Helicobacter pylori (H. pylori) infection with a first-line standard triple therapy (STT) has been decreasing in Korea. However, treatment outcomes of H. pylori infection in Yeongdong, Gangwon Province have been scarcely reported. This study aimed to investigate the treatment outcomes of H. pylori infection in a single tertiary care hospital with regional characteristics. @*Materials and Methods@#From July 2018 to June 2019, a total of 592 patients who underwent STT consisting of a proton pump inhibitor, amoxicillin, and clarithromycin for 7 to 14 days as a first-line H. pylori eradication therapy were included. Demographic data and treatment outcomes were retrospectively reviewed using medical records. @*Results@#The median age of 592 patients was 58 years (range 23 to 86) and 329 patients (55.6%) were men. The indication for eradication therapy included chronic atrophic gastritis (57.9%), peptic ulcer disease (19.6%), and gastric neoplasm after endoscopic resection (5.9%). Most patients (92.2%) received a 7-day course of STT. Eradication rate of STT was 64.0% (379/592). Rescue therapy was performed in 146 patients, and the final eradication rate reached 85.6% (507/592). @*Conclusions@#Eradication rate of STT in Yeongdong area of Gangwon Province was unsatisfactory, warranting the consideration of a first-line eradication regimen other than STT.

Gastric Malignant Peripheral Nerve Sheath Tumor in Type 1 Neurofibromatosis / 대한소화기학회지

Gastric malignant peripheral nerve sheath tumors (MPNSTs) are extremely rare spindle cell sarcomas that arise within the peripheral nerves of the gastrointestinal tract. MPNST can present as a mass that may or may not be accompanied by obstruction or bleeding.Type 1 neurofibromatosis (NF) is an autosomal dominant genetic disorder with an incidence of 1 in 2,500-3,000. Plexiform neurofibromas in Type 1 NF can undergo a malignant transformation to MPNSTs. Approximately half of the incidence of MPNST is associated with the NF-1 gene. MPNST behaves aggressively, and radical excisional surgery is important for treatment. Recurrence and metastasis are significant, even after a radical excision. Despite multidisciplinary treatment, the five-year survival rate is only 30-50%. This paper reports the case of a 47-year-old man with Type 1 NF who presented with hemorrhage of a gastric subepithelial lesion. He underwent surgery under the suspicion of a gastrointestinal stromal tumor, but it was diagnosed as MPNST after confirming the histopathological appearance and immunohistochemical profiles. In addition, the large mass invaded the spleen and diaphragm. Radical surgery was performed, and additional chemotherapy was administered. This paper reports the experience of a patient with NF 1 with advanced MPNST discovered due to a subepithelial lesion.

Development of the Korean Standardized Antimicrobial Administration Ratio as a Tool for Benchmarking Antimicrobial Use in Each Hospital

Background@#The Korea National Antimicrobial Use Analysis System (KONAS), a benchmarking system for antimicrobial use in hospitals, provides Korean Standardized Antimicrobial Administration Ratio (K-SAAR) for benchmarking. This article describes K-SAAR predictive models to enhance the understanding of K-SAAR, an important benchmarking strategy for antimicrobial usage in KONAS. @*Methods@#We obtained medical insurance claims data for all hospitalized patients aged ≥ 28 days in all secondary and tertiary care hospitals in South Korea (n = 347) from January 2019 to December 2019 from the Health Insurance Review & Assessment Service. Modeling was performed to derive a prediction value for antimicrobial use in each institution, which corresponded to the denominator value for calculating K-SAAR. The prediction values of antimicrobial use were modeled separately for each category, for all inpatients and adult patients (aged ≥ 15 years), using stepwise negative binomial regression. @*Results@#The final models for each antimicrobial category were adjusted for different significant risk factors. In the K-SAAR models of all aged patients as well as adult patients, most antimicrobial categories included the number of hospital beds and the number of operations as significant factors, while some antimicrobial categories included mean age for inpatients, hospital type, and the number of patients transferred from other hospitals as significant factors. @*Conclusion@#We developed a model to predict antimicrobial use rates in Korean hospitals, and the model was used as the denominator of the K-SAAR.

Comparative Morphological Study on Parotid and Submandibular Salivary Glands in Ovariectomized Rats / 치위생과학회지

Background@#Estrogen deficiency affects the structure and function of the salivary glands in women, leading to a decrease in salivary secretion and a change in the composition of saliva. Previous studies on changes in the salivary glands that cause estrogen deficiency have reported only partial results for the parotid and submandibular glands, and there are few comparative morphological studies of histological changes between the parotid and submandibular glands in ovariectomized rats (OVX) leading to estrogen deficiency. This study aimed to analyze the histopathological and histochemical changes in the parotid and submandibular salivary glands causing estrogen deficiency by using OVX, and to discuss the mechanism on these changes. @*Methods@#The parotid and submandibular glands from sacrificed control and OVX groups were fixed with cold 4% paraformaldehyde in phosphate buffer (pH 7.2). The tissues were dehydrated using a series of graded ethyl alcohol and embedded in paraffin. For histopathological analysis, sections cut to a thickness of 6 to 7 μm were stained with hematoxylin and eosin (H&E). For histochemical analysis, Periodic acid-Schiff (PAS), Alcian blue (AB, pH 2.5), and PAS+AB (pH 2.5 and pH 1) staining was performed. @*Results@#Histopathological analysis of OVX tissue showed that the parotid and submandibular salivary glands were broadly and clearly separated and divided into lobes. In OVX, acinar and ductal cells with condensed polymorphic or pyknotic nucleus, which are presumed to be characteristic of apoptotic cells, and degenerated cells with lipid deposition in cytoplasmic granules and ruptured membranes were increased. Histochemical analysis of OVX, confirmed an increase in the number and acidification of acinar secretory granules. @*Conclusion@#Histopathological and histochemical changes and the effects of estrogen deficiency are more evident in the submandibular salivary gland than in the parotid gland.

Effect of Denosumab on the Change of Osteoclast Precursors Compared to Zoledronate Treatment in Postmenopausal Women with Osteoporosis

Background@#A rapid increase in bone turnover and bone loss has been observed in response to the discontinuation of denosumab. It led to an acute increase in the fracture risk, similar to that observed in the untreated patients. We aimed to investigate the effect of denosumab on osteoclast (OC) precursor cells compared to that of zoledronate. @*Methods@#The study compared the effects of denosumab (60 mg/24-week) and zoledronate (5 mg/48-week) over 48 weeks in postmenopausal women with osteoporosis. From patients’ peripheral mononuclear cells, CD14+/CD11b+/vitronectin receptor (VNR)- and CD14+/CD11b+/VNR+ cells were isolated using fluorescent-activated cell sorting, representing early and late OC precursors, respectively. The primary endpoint was the changes in OC precursors after 48 weeks of treatment. @*Results@#Among the 23 patients, 11 were assigned to the denosumab group and 12 to the zoledronate group (mean age, 69 years). After 48 weeks, the changes in OC precursors were similar between and within the groups. Serum C-terminal telopeptide of type I collagen levels were inversely correlated with OC precursor levels after denosumab treatment (r=-0.72, P<0.001). Lumbar spine, femur neck, and total hip bone mineral density (BMD) increased in both groups. Lumbar spine BMD increased more significantly in the denosumab group than in the zoledronate group. @*Conclusions@#Denosumab and zoledronate treatments induced similar changes in OC precursors. During denosumab treatment, old age and suppressed bone turnover were associated with increased OC precursor cell populations. Further validation studies with prospective designs are required.

Efficacy and Safety of DA-8010, a Novel M3 Antagonist, in Patients With Overactive Bladder: A Randomized, Double-Blind Phase 2 Study / 대한배뇨장애요실금학회지

Purpose@#DA-8010 is a novel muscarinic M3 receptor antagonist with significant selectivity for bladder over salivary gland in preclinical studies. We evaluated the clinical efficacy and safety of DA-8010 in overactive bladder (OAB) patients. @*Methods@#This phase 2, randomized, double-blind, parallel-group, active reference- and placebo-controlled trial was conducted at 12 centers in South Korea (NCT03566134). Patients aged ≥19 years with OAB symptoms for ≥3 months were enrolled. Three hundred six patients (30.07% male) were randomized to 12 weeks of treatment among 4 groups; 2 experimental groups (DA-8010 2.5 or 5 mg), an active reference group (solifenacin 5 mg), and a placebo group. The change from the baseline of (=∆) 24-hour frequency at 12 weeks (primary endpoint), episodes of urgency, overall/urgency urinary incontinence, average/ maximum voided volume, nocturia, and patients’ subjective responses were analyzed. @*Results@#In the full analysis set, the mean (standard deviation) [median] values for ∆ 24-hour frequency at 12 weeks were -1.01 (2.44) [-1.33] for placebo, -1.22 (2.05) [-1.33] for DA-8010 2.5 mg, and -1.67 (2.25) [-1.67] for DA-8010 5 mg; DA-8010 5 mg showed a significant decrease compared with placebo (P=0.0413). At 4 and 8 weeks, both DA-8010 2.5 mg (P=0.0391 at 4 weeks, P=0.0335 at 8 weeks) and DA-8010 5 mg (P=0.0001 at 4 weeks, P=0.0210 at 8 weeks) showed significant decrease in ∆ 24-hour frequency compared with placebo. DA-8010 5 mg achieved a significant decrease in ∆ number of urgency episodes, compared with placebo at 4 (P=0.0278) and 8 (P=0.0092) weeks. Adverse drug reactions (ADRs) were observed in 3.95% of placebo, 6.67% of DA-8010 2.5 mg, 18.42% of DA-8010 5 mg, and 17.33% of solifenacin 5 mg groups. No serious ADRs were observed in any patient. @*Conclusions@#Both DA-8010 2.5 mg and 5 mg showed therapeutic efficacy for OAB without serious ADRs. Therefore, both dosages of DA-8010 can advance to a subsequent large-scale phase 3 trial.

Risk Factors for Transurethral Coagulation for Hemostasis During Holmium Laser Enucleation of the Prostate / 대한배뇨장애요실금학회지

Purpose@#We aimed to identify risk factors for transurethral coagulation (TUC) using bipolar electrocautery for hemostasis during holmium laser enucleation of the prostate (HoLEP) surgery for benign prostatic hyperplasia (BPH). @*Methods@#We analyzed the clinical outcomes of HoLEP surgery performed by a single surgeon between January 2010 and April 2020 at the Seoul National University Hospital. Patient characteristics and perioperative parameters were used to identify the risk factors for TUC. The TUC group was defined as a case of conversion to hemostasis using electrocautery during the hemostasis step after enucleation. @*Results@#Of 1,563 patients, 357 underwent TUC (TUC group; 22.8%) as an adjuvant (n=299, 19.1%) or salvage (n=58, 3.7%) therapy. Patients in the TUC group were older (mean±standard deviation, 70.6±7.3 years vs. 69.3±7.0 years; P=0.002), had more 5-alpha reductase inhibitor (5-ARI) use (35.6% vs. 25.9%, P35 mL. Therefore, TUC may be potentially necessary in patients with a large transition zone volume in patients with BPH.

Development and Roll-Out of A Coronavirus Disease 2019 Clinical Pathway for Standardized Qualified Care in Public Hospitals in Korea / 감염과화학요법

Despite the coronavirus disease 2019 (COVID-19) vaccination roll-out, variant-related outbreaks have occurred repeatedly in Korea. Although public hospitals played a major role in COVID-19 patients’ care, difficulty incorporating evolving COVID-19 treatment guidelines called for a clinical pathway (CP). Eighteen public hospitals volunteered, and a professional review board was created. CPs were formulated containing inclusion/exclusion criteria, application flow charts, and standardized order sets. After CP roll-out, key parameters improved, such as increased patient/staff five-point satisfaction scores (0.41/0.57) and decreased hospital stays (1.78 days)/medical expenses (17.5%). The CPs were updated consistently after roll-out as new therapeutics drugs were introduced and quarantine policies changed.

Surveillance of Close Contacts and Implications of Pediatric Patients with COVID-19–Experiences from a Single Residential Treatment Center

Residential treatment centers (RTCs) are successful in isolating and closely monitoring adults confirmed with coronavirus disease 2019 (COVID-19), but there are concerns for children who need care. This study was conducted as a retrospective analysis of the surveillance of guardians who entered an RTC with infected pediatric patients to identify the secondary attack rate of COVID-19 to close contacts in a single RTC and to provide directions for developing guidelines for caregivers who co-isolate with infected children. When caregivers were admitted to this RTC, aside from negative confirmation before discharge, tests were additionally performed one or two times. There were 57 index children and adolescent patients who entered the RTC with their parents as caregivers. The secondary attack rate by pediatric patients to close contacts outside their households was 25% (95% confidence interval, 10.0 to 40.0) (8 out of 32 contacts). The transmissibility of SARS-CoV-2 in children was close to zero at 6 days after the confirmation tests. It is reasonable to test the close contacts of pediatric patients after 7 days of isolation to identify infections among caregivers.

A Comparative Study of an Anti-Thrombotic Small-Diameter Vascular Graft with Commercially Available e-PTFE Graft in a Porcine Carotid Model

BACKGROUND@#We have designed a reinforced drug-loaded vascular graft composed of polycaprolactone (PCL) and polydioxanone (PDO) via a combination of electrospinning/3D printing approaches. To evaluate its potential for clinical application, we compared the in vivo blood compatibility and performance of PCL/PDO ? 10%DY grafts doped with an antithrombotic drug (dipyridamole) with a commercial expanded polytetrafluoroethylene (e-PTFE) graft in a porcine model. @*METHODS@#A total of 10 pigs (weight: 25–35 kg) were used in this study. We made a new 5-mm graft with PCL/PDO composite nanofiber via the electrospinning technique. We simultaneously implanted a commercially available e-PTFE graft (n = 5) and our PCL/PDO ? 10%DY graft (n = 5) into the carotid arteries of the pigs. No anticoagulant/antiplatelet agent was administered during the follow-up period, and ultrasonography was performed weekly to confirm the patency of the two grafts in vivo. Four weeks later, we explanted and compared the performance of the two grafts by histological analysis and scanning electron microscopy (SEM). @*RESULTS@#No complications, such as sweating on the graft or significant bleeding from the needle hole site, were seen in the PCL/PDO ? 10%DY graft immediately after implantation. Serial ultrasonographic examination and immunohistochemical analysis demonstrated that PCL/PDO ? 10%DY grafts showed normal physiological blood flow and minimal lumen reduction, and pulsed synchronously with the native artery at 4 weeks after implantation. However, all e-PTFE grafts occluded within the study period. The luminal surface of the PCL/PDO ? 10%DY graft in the transitional zone was fully covered with endothelial cells as observed by SEM. @*CONCLUSION@#The PCL/PDO ? 10%DY graft was well tolerated, and no adverse tissue reaction was observed in porcine carotid models during the short-term follow-up. Colonization of the graft by host endothelial and smooth muscle cells coupled with substantial extracellular matrix production marked the regenerative capability. Thus, this material may be an ideal substitute for vascular reconstruction and bypass surgeries. Long-term observations will be necessary to determine the anti-thrombotic and remodeling potential of this device.