BACKGROUND: Implant supporting materials are currently used in breast reconstruction. However, when used in humans, they are associated with several problems. To address these issues, a new mesh called TissueDerm was created by combining a collagen sponge with a 3D printed polycaprolactone (PCL) mesh. It has shown promising results in pig experiments and could potentially replace the most commonly used acellular dermal matrix (ADM) for breast reconstruction. METHODS: Four 12-month-old minipigs were used in this experiment. Silicone implants were wrapped with ADM or TissueDerm, and the breast tissue was excised and implanted along with the wrapped implants. Three months later, the minipigs were sacrificed and the skin and mammary gland tissue surrounding the implants were harvested for further analysis. Histological analyses and immunostaining were performed. RESULTS: Although there was no significant difference in capsule thickness between the ADM and TissueDerm groups, collagen was more involved in TissueDerm, leading to better tissue regeneration. TissueDerm also induced lower levels of inflammatory markers TNF-a and IL-6 compared to ADM. However, capsules induced with ADM had significantly higher collagen fiber alignment and alpha-smooth muscle actin (a-SMA) positive immunoreactivity, suggesting that TissueDerm may be less likely to cause spherical contractures in the porcine model compared to ADM. CONCLUSIONS The study found that TissueDerm has advantages over ADM in terms of easier tissue invasion and reduced spheroidization in a porcine model. The results showed that TissueDerm is a promising new mesh for implantbased breast reconstruction (IBBR) and could potentially replace ADM.

Background/Aims: Among several methods used to prevent endoscopic submucosal dissection (ESD) bleeding, the recently developed hemostatic powder (HP) has few technical limitations and is relatively easy-to-use. This study aimed to analyze the hemostatic effects and mechanisms of two HPs using a porcine upper gastrointestinal hemorrhage model. Methods: We evaluated HPs (Endospray and epidermal growth factor [EGF]-endospray) for adhesion, waterproofing ability, permeability, and absorption in vitro. ESD was performed to induce bleeding ulcers in the porcine stomachs. In a total of three pigs, three bleeding ulcers per animal were generated. Hemostasis and rebleeding were evaluated endoscopically. After 72 hours, the animals were sacrificed, and histologically analyzed. Results: The water absorption of HPs was over 20 times the initial value within 30 minutes. The gelated HPs completely blocked water penetration into the applied site within 5 minutes and strongly adhered to the Petri-dish surface for up to 6 hours. The initial hemostasis rates within 5 minutes were 33.3%, 100.0%, and 66.7%, and the rebleeding rates at 6 to 72 hours after HP application were 33.3%, 16.7%, and 33.3% (control, Endospray, and EGF-endospray groups, respectively). Histological analysis revealed the thickness of the regenerated mucosa (522.1, 514.5, and 680.3 µm) and the submucosal layer (1,510.3, 2,848.2, and 3,062.3 µm) and the number of newly formed blood vessels (15.3, 17.9, and 20.5) in the control, Endospray, and EGFendospray groups, respectively. Conclusions The endoscopic HPs demonstrated the ability to elicit effective initial hemostasis and the histological ulcer-healing effect of EGF in an animal model of hemorrhagic gastric ulcers.

Background: The purpose of this study was to evaluate the effect of vanishing twin (VT) on maternal serum marker concentrations and nuchal translucency (NT). Methods: This is a secondary analysis of a multicenter prospective cohort study in 12 institutions. Serum concentrations of pregnancy-associated plasma protein-A in the first trimester and alpha-fetoprotein (AFP), total human chorionic gonadotrophin, unconjugated estriol, and inhibin A in the second trimester were measured, and NT was measured between 10 and 14 weeks of gestation. Results: Among 6,793 pregnant women, 5,381 women were measured for serum markers in the first or second trimester, including 65 cases in the VT group and 5,316 cases in the normal singleton group. The cases in the VT group had a higher median multiple of the median value of AFP and inhibin A than the normal singleton group. The values of other serum markers and NT were not different between the two groups. After the permutation test with adjustment,AFP and inhibin A remained significant differences. The frequency of abnormally increased AFP was also higher in the VT group than in the normal singleton group. Conclusion VT can be considered as an adjustment factor for risk assessment in the secondtrimester serum screening test.

BACKGROUND: Breast cancer patients suffer from lowered quality of life (QoL) after surgery. Breast conservancy surgery (BCS) such as partial mastectomy is being practiced and studied as an alternative to solve this problem. This study confirmed breast tissue reconstruction in a pig model by fabricating a 3-dimensional (3D) printed Polycaprolactone spherical scaffold (PCL ball) to fit the tissue resected after partial mastectomy. METHODS: A 3D printed Polycaprolactone spherical scaffold with a structure that can help adipose tissue regeneration was produced using computer-aided design (CAD). A physical property test was conducted for optimization. In order to enhance biocompatibility, collagen coating was applied and a comparative study was conducted for 3 months in a partial mastectomy pig model. RESULTS: In order to identify adipose tissue and fibroglandular tissue, which mainly constitute breast tissue, the degree of adipose tissue and collagen regeneration was confirmed in a pig model after 3 months. As a result, it was confirmed that a lot of adipose tissue was regenerated in the PCL ball, whereas more collagen was regenerated in the collagen-coated Polycaprolactone spherical scaffold (PCL–COL ball). In addition, as a result of confirming the expression levels of TNF-a and IL-6, it was confirmed that PCL ball showed higher levels than PCL–COL ball. CONCLUSION Through this study, we were able to confirm the regeneration of adipose tissue through a 3-dimensional structure in a pig model. Studies were conducted on medium and large-sized animal models for the final purpose of clinical use and reconstruction of human breast tissue, and the possibility was confirmed.

Background: Firefighters inevitably encounter emotionally and physically stressful situations at work. Even firefighters without diagnosed post-traumatic stress disorder receive clinical attention because the nature of the profession exposes them to repetitive trauma and high occupational stress. This study investigated gray matter abnormalities related to high occupational stress in firefighters using voxel-based morphometry (VBM) and surface-based morphometry (SBM). Methods: We assessed 115 subjects (112 males and 3 females) using magnetic resonance imaging and evaluated occupational stress by the Korean Occupational Stress Scale-26 (KOSS-26). Subjects were classified into highly or lowly stressed groups based on the median value of the KOSS-26. Results: In VBM analysis, we found that firefighters with high occupational stress had lower gray matter volume (GMV) in both sides of the insula, the left amygdala, the right medial prefrontal cortex (mPFC), and the anterior cingulate cortex than firefighters with low occupational stress. In SBM analysis based on regions of interest, the GMV of the bilateral insula and right mPFC were also lower in the highly stressed group. Within the highly stressed group, low GMV of the insula was significantly correlated with the length of service (left: r = −0.347, P = 0.009; right: r = −0.333, P = 0.012). Conclusion Our findings suggest that regional GMV abnormalities are related to occupational stress. Regional gray matter abnormalities and related emotional dysregulation may contribute to firefighter susceptibility to burnout.

Background: The purpose of this study is to examine the combined effects of organizational climate (OC) with emotional labor (EL) on turnover intention in Korean firefighters. Methods: The data were obtained from the study Firefighters Research: Enhancement of Safety and Health. A total of 4,860 firefighters whose main duty was providing “emergency medical aid” were included. To examine the effects of OC on the relationships between five subscales of EL and turnover intention, four groups were created using various combinations of OC (“good” vs. “bad”) and EL (“normal” vs. “risk”): (1) “good” and “normal” (Group I), (2) “bad” and “normal” (Group II), (3) “good” and “risk” (Group III), and (4) “bad” and “risk” (Group IV). Multivariate logistic regression analyses were performed to estimate the risk of turnover intention for the combinations of OC and EL. Results: The results showed turnover intention was significantly higher in the group with “bad” OC (17.7%) than in that with “good” OC (7.6%). Combined effects of OC and EL on turnover intention were found in all five subscales with the exception of Group I for emotional demands and regulation. Groups II, III, and IV were more likely to experience risks of turnover intention than Group I (p for trend <0.001). Conclusions A positive and cooperative OC plays a role in decreasing the risk of turnover intention and in attenuating the negative effects of EL on turnover intention in firefighters.

Background: The purpose of this study is to examine the combined effects of organizational climate (OC) with emotional labor (EL) on turnover intention in Korean firefighters. Methods: The data were obtained from the study Firefighters Research: Enhancement of Safety and Health. A total of 4,860 firefighters whose main duty was providing “emergency medical aid” were included. To examine the effects of OC on the relationships between five subscales of EL and turnover intention, four groups were created using various combinations of OC (“good” vs. “bad”) and EL (“normal” vs. “risk”): (1) “good” and “normal” (Group I), (2) “bad” and “normal” (Group II), (3) “good” and “risk” (Group III), and (4) “bad” and “risk” (Group IV). Multivariate logistic regression analyses were performed to estimate the risk of turnover intention for the combinations of OC and EL. Results: The results showed turnover intention was significantly higher in the group with “bad” OC (17.7%) than in that with “good” OC (7.6%). Combined effects of OC and EL on turnover intention were found in all five subscales with the exception of Group I for emotional demands and regulation. Groups II, III, and IV were more likely to experience risks of turnover intention than Group I (p for trend <0.001). Conclusions A positive and cooperative OC plays a role in decreasing the risk of turnover intention and in attenuating the negative effects of EL on turnover intention in firefighters.

Firefighters ; Humans ; Suicidal Ideation

The cellular entry of severe respiratory syndrome coronavirus-2 (SARS-CoV-2) is mediated by interaction with the human angiotensin-converting enzyme 2 (ACE2), a receptor that is expressed on both lung and intestinal epithelial cells. We performed a quantitative proteomic analysis to investigate the expression of possible receptors for SARS-CoV-2 in the intestinal mucosa of 23 patients with chronic colitis. ACE2 expression was low and remained unaltered in the gut of patients with ulcerative colitis (UC), Crohn’s disease (CD), intestinal Behćet’s disease (BD), and intestinal tuberculosis (TB), when compared with that of healthy individuals. Additionally, the expression levels of some probable co-receptors, including dipeptidyl peptidase 4 (DPP4), aminopeptidase N (AMPN), and glutamyl aminopeptidase (AMPE), were unchanged in the affected UC, CD, intestinal BD, and intestinal TB colon mucosa samples. In conclusion, gut inflammation associated with chronic colitis does not mediate a further increase in the cellular entry of SARS-CoV-2.

OBJECTIVES: It is well-known that post-traumatic stress disorder (PTSD) among firefighters contributes to their job-related stress. However, the relationship between burnout and PTSD in firefighters has rarely been studied. This study therefore explored the association between burnout and its related factors, such as trauma and violence, and PTSD symptoms among firefighters in Korea. METHODS: A total of 535 firefighters participated in the Firefighter Research on Enhancement of Safety & Health study at 3 university hospitals from 2016 to 2017. The 535 participants received a baseline health examination, including questionnaires assessing their mental health. A Web-based survey was also conducted to collect data on job-related stress, history of exposure to violence, burnout, and trauma experience. The associations among burnout, its related factors, and PTSD symptoms were investigated using structural equation modeling. RESULTS: Job demands (β=0.411, p<0.001) and effort-reward balance (β=-0.290, p<0.001) were significantly related to burnout. Burnout (β=0.237, p<0.001) and violence (β=0.123, p=0.014) were significantly related to PTSD risk. Trauma (β=0.131, p=0.001) was significantly related to burnout; however, trauma was not directly associated with PTSD scores (β=0.085, p=0.081). CONCLUSIONS Our results show that burnout and psychological, sexual, and physical violence at the hands of clients directly affected participants’ PTSD symptoms. Burnout mediated the relationship between trauma experience and PTSD.