Three-Dimensional Skin Tissue Printing with Human Skin Cell Lines and Mouse Skin-Derived Epidermal and Dermal Cells.

Since the skin covers most surfaces of the body, it is susceptible to damage, which can be fatal depending on the degree of injury to the skin because it defends against external attack and protects internal structures. Various types of artificial skin are being studied for transplantation to repair damaged skin, and recently, the production of replaceable skin using three-dimensional (3D) bioprinting technology has also been investigated. In this study, skin tissue was produced using a 3D bioprinter with human skin cell lines and cells extracted from mouse skin, and the printing conditions were optimized. Gelatin was used as a bioink, and fibrinogen and alginate were used for tissue hardening after printing. Printed skin tissue maintained a survival rate of 90% or more when cultured for 14 days. Culture conditions were established using 8 mM calcium chloride treatment and the skin tissue was exposed to air to optimize epidermal cell differentiation. The skin tissue was cultured for 14 days after differentiation induction by this optimized culture method, and immunofluorescent staining was performed using epidermal cell differentiation markers to investigate whether the epidermal cells had differentiated. After differentiation, loricrin, which is normally found in terminally differentiated epidermal cells, was observed in the cells at the tip of the epidermal layer, and cytokeratin 14 was expressed in the lower cells of the epidermis layer. Collectively, this study may provide optimized conditions for bioprinting and keratinization for three-dimensional skin production.

The Effect of Stroke on Pharyngeal Laterality During Swallowing.

OBJECTIVE: To investigate whether patterns of dysphagia and swallowing laterality differ according to the location of brain lesions in patients with stroke. METHODS: Patients with stroke >20 years of age were enrolled in this study. A videofluoroscopic swallowing study (VFSS) including the anterior-posterior view was used to assess swallowing. Patterns of swallowing were classified into three types according to the width of barium sulfate flow while passing the pharyngoesophageal segment: right-side-dominant flow, left-side-dominant flow, and no laterality in flow. Laterality was defined when the width of one side was twice or more the width of the other side. RESULTS: A total of 92 patients who underwent swallowing function evaluations by VFSS were enrolled from Sep-tember 2012 to May 2013. Of these, 72 patients had supratentorial lesions (group I) and 20 patients had infratento-rial lesions (group II). Only 10 patients (13.9%) in group I and three patients (15.0%) in group II showed laterality. Of these 13 patients, laterality occurred on the left side regardless of the side of the brain lesion. No relationships were found between swallowing laterality and location of stroke or motor weakness. CONCLUSION: The results suggest that swallowing laterality was not prevalent among patients with stroke and that lesion side, location of the brain lesion, or motor weakness did not influence swallowing laterality. Although stroke can cause symptoms of dysphagia, it is difficult to conclude that stroke has a crucial impact on swallowing laterality.

Dysphagia in tongue cancer patients.

OBJECTIVE: To identify risk factors for dysphagia in tongue cancer patients. Dysphagia is a common complication of surgery, radiotherapy, and chemotherapy in tongue cancer patients. Previous studies have attempted to identify risk factors for dysphagia in patients with head and neck cancer, but no studies have focused specifically on tongue cancer patients. METHODS: This study was conducted on 133 patients who were diagnosed with tongue cancer and who underwent a videofluoroscopy swallowing study (VFSS) between January 2007 and June 2012 at the Asan Medical Center. Data collected from the VFSS were analyzed retrospectively. Patients with aspiration were identified. RESULTS: Patients showed a higher incidence of inadequate tongue control, inadequate chewing, delayed oral transit time, aspiration or penetration, vallecular pouch and pyriform residue, and inadequate laryngeal elevation after surgery. Moreover, male gender, extensive tumor resection, a higher node stage, and more extensive lymph node dissection were major risk factors for aspiration in tongue cancer patients. CONCLUSION: Tongue cancer patients have difficulties in the pharyngeal phase as well as the oral phase of swallowing. These difficulties can worsen after tongue cancer surgery. Gender, the extent of tumor resection, and lymph node metastasis affect swallowing in tongue cancer patients. Physicians should take these risk factors into account when administering swallowing therapy to tongue cancer patients.

Effect of virtual reality on cognitive dysfunction in patients with brain tumor.

OBJECTIVE: To investigate whether virtual reality (VR) training will help the recovery of cognitive function in brain tumor patients. METHODS: Thirty-eight brain tumor patients (19 men and 19 women) with cognitive impairment recruited for this study were assigned to either VR group (n=19, IREX system) or control group (n=19). Both VR training (30 minutes a day for 3 times a week) and computer-based cognitive rehabilitation program (30 minutes a day for 2 times) for 4 weeks were given to the VR group. The control group was given only the computer-based cognitive rehabilitation program (30 minutes a day for 5 days a week) for 4 weeks. Computerized neuropsychological tests (CNTs), Korean version of Mini-Mental Status Examination (K-MMSE), and Korean version of Modified Barthel Index (K-MBI) were used to evaluate cognitive function and functional status. RESULTS: The VR group showed improvements in the K-MMSE, visual and auditory continuous performance tests (CPTs), forward and backward digit span tests (DSTs), forward and backward visual span test (VSTs), visual and verbal learning tests, Trail Making Test type A (TMT-A), and K-MBI. The VR group showed significantly (p<0.05) better improvements than the control group in visual and auditory CPTs, backward DST and VST, and TMT-A after treatment. CONCLUSION: VR training can have beneficial effects on cognitive improvement when it is combined with computer-assisted cognitive rehabilitation. Further randomized controlled studies with large samples according to brain tumor type and location are needed to investigate how VR training improves cognitive impairment.