Infection control for COVID-19 in hospital examination room.

Healthcare providers are vulnerable to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) because of their close proximity to patients with coronavirus disease 2019. SARS-CoV-2 is mainly transmitted via direct and indirect contact with respiratory droplets, and its airborne transmission has also been identified. However, evidence for environmental factors is scarce, and evidence-based measures to minimize the risk of infection in clinical settings are insufficient. Using computational fluid dynamics, we simulated exhalation of large and small aerosol particles by patients in an otolaryngology examination room, where medical procedures require the removal of a face mask. The effects of coughing were analyzed, as well as those of humidity as a controllable environmental factor and of a suction device as an effective control method. Our results show that a suction device can minimize aerosol exposure of healthcare workers by efficiently removing both large (11.6-98.2%) and small (39.3-99.9%) aerosol particles. However, for coughing patients, the removal efficiency varies inversely with the particle size, and the humidity notably affects the aerosol behavior, indicating the need for countermeasures against smaller aerosols. Overall, these results highlight the potential and limitation of using a suction device to protect against SARS-CoV-2 and future respiratory infections.

Endoscopic laser treatment for urine leakage caused by an isolated calyx after robot-assisted partial nephrectomy.

INTRODUCTION: An isolated calyx is a rare complication in which the renal calyx and pelvis are disconnected. The treatment is often complicated. CASE PRESENTATION: An 81-year-old man underwent robot-assisted partial nephrectomy for the treatment of renal cell carcinoma (cT1bN0M0). Postoperatively, urine leakage was observed and did not improve with conservative measures. Retrograde pyelography and computed tomography revealed that urine leakage originated from the isolated calyx caused by infundibular stenosis. Endoscopic treatment via the transurethral approach was selected to preserve renal function. Ureteroscopy showed that the upper calyx was completely obstructed by the sutures. Therefore, we cut the suture thread using laser, and a ureteral stent was placed in the upper renal calyx. Fluid drainage immediately disappeared after the procedure, and the patient did not lose renal function. CONCLUSION: Endoscopic management might be an option for isolated calyx after robot-assisted partial nephrectomy.

Novel bone microenvironment model of castration-resistant prostate cancer with chitosan fiber matrix and osteoblasts.

The interaction between prostate cancer cells and osteoblasts is essential for the development of bone metastasis. Previously, novel androgen receptor axis-targeted agents (ARATs) were approved for metastatic castration-naïve and non-metastatic castration-resistant prostate cancer (CRPC); both of which are pivotal for investigating the association between the bone microenvironment and tumors. The present study established a novel in vitro 3D microenvironment model that simulated the bone microenvironment of CRPC, and evaluated the drug susceptibility of ARATs and the efficacy of the combination of abiraterone and dutasteride. Green fluorescent protein-transferred C4-2 cells (a CRPC cell line) and red fluorescent protein-transferred human osteoblasts differentiated from human mesenchymal stem cells were co-cultured in chitosan nanofiber matrix-coated culture plates to simulate the 3D scaffold of the bone microenvironment. The growth of C4-2 was quantified using live-cell imaging and the Cell3 iMager duos analysis system. The growth of C4-2 colonies were quantified for a maximum of 30 days. The expression of TGF-ß increased and promoted EMT in C4-2 cells co-cultured with osteoblasts, indicating resistance to ARATs. The IC50 of each drug and the combination effect of abiraterone and dutasteride were evaluated using this model. Combination treatment with abiraterone and dutasteride synergistically inhibited the growth of C2-4 colonies compared with individual investigational agents. This could be attributed to the reduction of 3-keto-5α-abiraterone, an androgen receptor agonist. The bone microenvironment model of the present study is unique and useful for evaluating new drug susceptibility testing in prostate cancer cells. This model may help to reveal the unknown mechanisms underlying micro- to clinical bone metastasis in prostate cancer.