Simulation Method for the Physical Deformation of a Three-Dimensional Soft Body in Augmented Reality-Based External Ventricular Drainage / 대한의료정보학회지

Objectives@#Intraoperative navigation reduces the risk of major complications and increases the likelihood of optimal surgical outcomes. This paper presents an augmented reality (AR)-based simulation technique for ventriculostomy that visualizes brain deformations caused by the movements of a surgical instrument in a three-dimensional brain model. This is achieved by utilizing a position-based dynamics (PBD) physical deformation method on a preoperative brain image. @*Methods@#An infrared camera-based AR surgical environment aligns the real-world space with a virtual space and tracks the surgical instruments. For a realistic representation and reduced simulation computation load, a hybrid geometric model is employed, which combines a high-resolution mesh model and a multiresolution tetrahedron model. Collision handling is executed when a collision between the brain and surgical instrument is detected. Constraints are used to preserve the properties of the soft body and ensure stable deformation. @*Results@#The experiment was conducted once in a phantom environment and once in an actual surgical environment. The tasks of inserting the surgical instrument into the ventricle using only the navigation information presented through the smart glasses and verifying the drainage of cerebrospinal fluid were evaluated. These tasks were successfully completed, as indicated by the drainage, and the deformation simulation speed averaged 18.78 fps. @*Conclusions@#This experiment confirmed that the AR-based method for external ventricular drain surgery was beneficial to clinicians.

Maladaptive Alterations of Defensive Response Following Developmental Complex Stress in Rats

Objective@#Despite the etiological significance of complex developmental trauma in adult personality disorders and treatment-resistant depression, neurobiological studies have been rare due to the lack of useful animal models. As a first step, we devised an animal model to investigate the effects of multiple trauma-like stress during different developmental periods. @*Methods@#Twenty-one male Sprague-Dawley rats were classified into 3 groups based on the stress protocol: fear conditioning control (FCC, n = 6), complex stress (ComS, n = 9), and control (n = 6). While the ComS experienced three types of stress (maternal separation, juvenile isolation, electric foot shock), the FCC only experienced an electric foot shock stress and the control never experienced any. We compared fear responses at postnatal day (PND) 29 and PND 56 through freezing time per episode (FTpE), total freezing time (TFT), total freezing episodes (TFE), and ultrasonic vocalization (USV). @*Results@#ComS showed the longest FTpE in the conditioned fear response test. ComS and FCC exhibited the longer TFT and these two groups only displayed USV. ComS show difference TFE between PND 29 and PND 56. @*Conclusion@#The results of this investigation show that complex stress may affect not quantity of fear response but characteristics of fear response. Longer FTpE may be associated with tonic immobility which could be considered as a failed self-protective reaction and might be analogous to a sign of inappropriate coping strategy and self-dysregulation in complex trauma patients.

Establishment of Immortalized Primary Human Foreskin Keratinocytes and Their Application to Toxicity Assessment and Three Dimensional Skin Culture Construction

In spite of frequent usage of primary human foreskin keratinocytes (HFKs) in the study of skin biology, senescence-induced blockage of in vitro proliferation has been a big hurdle for their effective utilization. In order to overcome this passage limitation, we first isolated ten HFK lines from circumcision patients and successfully immortalized four of them via a retroviral transduction of high-risk human papillomavirus (HPV) E6 and E7 oncogenes. We confirmed expression of a keratinocyte marker protein, keratin 14 and two viral oncoproteins in these immortalized HFKs. We also observed their robust responsiveness to various exogenous stimuli, which was evidenced by increased mRNA expression of epithelial differentiation markers and pro-inflammatory genes in response to three reactive chemicals. In addition, their applicability to cytotoxicity assessment turned out to be comparable to that of HaCaT cells. Finally, we confirmed their differentiation capacity by construction of well-stratified three dimensional skin cultures. These newly established immortalized HFKs will be valuable tools not only for generation of in vitro skin disease models but also for prediction of potential toxicities of various cosmetic chemicals.

Comparison of the Characteristics of Anhedonia between Patients with Schizophrenia and Depressive Disorder / 신경정신의학

OBJECTIVES: Anhedonia, defined as an inability to experience pleasure, has been considered to be a core feature of schizophrenia and depression. The purpose of the present study was to compare the specific characteristics of anhedonia in patients with the two illnesses by examining hedonic capacity during phased hedonic experience. METHODS: Hedonic rating tasks, using the film clips of physical and social hedonic stimuli and neutral stimuli, were performed by 29 patients with schizophrenia, 20 patients with depression, and 29 normal controls. Each task consisted of 'preview phase' with insufficient emotional information, and a subsequent 'theme phase' with sufficient emotional information. RESULTS: In normal controls, the mean hedonic score was increased in the theme phase compared with the preview phase, suggesting an appropriate augmentation of the hedonic response. In patients with schizophrenia, hedonic scores in the preview phase were comparable with those in normal controls, but showed deficient augmentation in the theme phase. In patients with depressive disorder, the range of increments in scores between the preview and theme phases was normal, but the scores themselves were lower in both phases than in the other two groups. CONCLUSION: The results indicate that patients with schizophrenia show a deficient augmentation of the hedonic response, whereas patients with depressive disorder have a pervasive lack of hedonic capacity.