Dynamic analysis of a needle insertion for soft materials: Arbitrary Lagrangian-Eulerian-based three-dimensional finite element analysis

Background: Our goal was to develop a three-dimensional finite element model that enables dynamic analysis of needle insertion for soft materials. To demonstrate large deformation and fracture, we used the arbitrary Lagrangian-Eulerian (ALE) method for fluid analysis. We performed ALE-based finite element analysis for 3% agar gel and three types of copper needle with bevel tips. Methods: To evaluate simulation results, we compared the needle deflection and insertion force with corresponding experimental results acquired with a uniaxial manipulator. We studied the shear stress distribution of agar gel on various time scales. Results: For 30°, 45°, and 60°, differences in deflections of each needle between both sets of results were 2.424, 2.981, and 3.737. mm, respectively. For the insertion force, there was no significant difference for mismatching area error (p<0.05) between simulation and experimental results. Conclusions: Our results have the potential to be a stepping stone to develop pre-operative surgical planning to estimate an optimal needle insertion path for MR image-guided microwave coagulation therapy and for analyzing large deformation and fracture in biological tissues. © 2014 Elsevier Ltd.Yamaguchi S., Tsutsui K., Satake K., et al. Dynamic analysis of a needle insertion for soft materials: Arbitrary Lagrangian-Eulerian-based three-dimensional finite element analysis. Computers in Biology and Medicine 53, 42 (2014); https://doi.org/10.1016/j.compbiomed.2014.07.012

The Effect of Seat Back Inclination on Spinal Alignment in Automotive Seating Postures

Experimental studies have demonstrated a relationship between spinal injury severity and vertebral kinematics, influenced by the initial spinal alignment of automotive occupants. Spinal alignment has been considered one of the possible causes of gender differences in the risk of sustaining spinal injuries. To predict vertebral kinematics and investigate spinal injury mechanisms, including gender-related mechanisms, under different seat back inclinations, it is needed to investigate the effect of the seat back inclination on initial spinal alignment in automotive seating postures for both men and women. The purpose of this study was to investigate the effect of the seat back inclination on spinal alignments, comparing spinal alignments of automotive seating postures in the 20\ub0 and 25\ub0 seat back angle and standing and supine postures. The spinal columns of 11 female and 12 male volunteers in automotive seating, standing, and supine postures were scanned in an upright open magnetic resonance imaging system. Patterns of their spinal alignments were analyzed using Multidimensional Scaling presented in a distribution map. Spinal segmental angles (cervical curvature, T1 slope, total thoracic kyphosis, upper thoracic kyphosis, lower thoracic kyphosis, lumbar lordosis, and sacral slope) were also measured using the imaging data. In the maximum individual variances in spinal alignment, a relationship between the cervical and thoracic spinal alignment was found in multidimensional scaling analyses. Subjects with a more lordotic cervical spine had a pronounced kyphotic thoracic spine, whereas subjects with a straighter to kyphotic cervical spine had a less kyphotic thoracic spine. When categorizing spinal alignments into two groups based on the spinal segmental angle of cervical curvature, spinal alignments with a lordotic cervical spine showed significantly greater absolute average values of T1 slope, total thoracic kyphosis, and lower thoracic kyphosis for both the 20\ub0 and 25\ub0 seat back angles. For automotive seating postures, the gender difference in spinal alignment was almost straight cervical and less-kyphotic thoracic spine for the female subjects and lordotic cervical and more pronounced kyphotic thoracic spine for the male subjects. The most prominent influence of seatback inclination appeared in Total thoracic kyphosis, with increased angles for 25\ub0 seat back, 8.0\ub0 greater in spinal alignments with a lordotic cervical spine, 3.2\ub0 greater in spinal alignments with a kyphotic cervical spine. The difference in total thoracic kyphosis between the two seatback angles and between the seating posture with the 20\ub0 seat back angle and the standing posture was greater for spinal alignments with a lordotic cervical spine than for spinal alignments with a kyphotic cervical spine. The female subjects in this study had a tendency toward the kyphotic cervical spine. Some of the differences between average gender-specific spinal alignments may be explained by the findings observed in the differences between spinal alignments with a lordotic and kyphotic cervical spine

ウサギ肝障害モデルにおける ^<31>PーNMRによる膜リン脂質代謝動態の研究

科学研究費補助金研究成果報告書研究種目: 一般研究(C)研究期間: 1990～1990課題番号: 02807237研究代表者: 森川 茂廣（滋賀医科大学・医学部・助手）研究分担者: 犬伏 俊郎（滋賀医科大学・医学部・教授

Oxidative stress induction of DJ-1 protein in reactive astrocytes scavenges free radicals and reduces cell injury

Astrocytes, one of the predominant types of glial cells, function as both supportive and metabolic cells for the brain. Under cerebral ischemia/reperfusion-induced oxidative conditions, astrocytes accumulate and activate in the ischemic region. DJ-1 has recently been shown to be a sensor of oxidative stress in living cells. However, the function of astrocytic DJ-1 is still unknown. In the present study, to clarify the effect of astrocytic DJ-1 protein under massive oxidative insult, we used a focal ischemic rat model that had been subjected to middle cerebral artery occlusion (MCAO) and reperfusion. We then investigated changes in the distribution of DJ-1 in astrocytes, DJ-1 release from cultured astrocytes, and the effects of recombinant DJ-1 protein on hydrogen peroxide (H2O2)-induced death in normal and DJ-1-knockdown SH-SY5Y cells and on in vitro scavenging of hydroxyl radicals (•OH) by electron spin resonance spectrometry. At 24 h after 2-h MCAO and reperfusion, an infarct lesion was markedly observed using magnetic resonance imaging and 2,3,5-triphenyltetrazolium chloride staining. In addition, reactive astrocytes enhanced DJ-1 expression in the penumbral zone of the ischemic core and that DJ-1 protein was extracellularly released from astrocytes by H2O2 in in vitro primary cultures. Although DJ-1-knockdown SH-SY5Y cells were markedly vulnerable to oxidative stress, treatment with glutathione S-transferase-tagged recombinant human DJ-1 protein (GST-DJ-1) significantly inhibited H2O2-induced cell death. In addition, GST-DJ-1 protein directly scavenged •OH. These results suggest that oxidative stress induces the release of astrocytic DJ-1 protein, which may contribute to astrocyte-mediated neuroprotection

IMAGING OF AVASCULAR NECROSIS OF FEMORAL HEAD IN SPONTANEOUS HYPERTENSIVE RATS AND ITS EXPERIMENTAL MODEL

科学研究費補助金研究成果報告書研究種目: 基盤研究(C)研究期間: 1997～2000課題番号: 09670927研究代表者: 高田 政彦（滋賀医科大学・医学部・講師）研究分担者: 森川 茂廣（滋賀医科大学・分子神経科学研究センター・助教授）研究分担者: 山本 逸雄（滋賀医科大学・医学部・助教授

Device development to measure cellular activity in brain

科学研究費補助金研究成果報告書研究種目: 国際学術研究研究期間: 1997～1998課題番号: 09044287研究代表者: 犬伏 俊郎（滋賀医科大学・分子神経生物学研究センター・教授）研究分担者: 森川 茂広（滋賀医科大学・分子神経生物学研究センター・助教授）研究分担者: 椎野 顯彦（滋賀医科大学・医学部・助手

Investigating representative whole spinal alignments in a car occupant posture

AbstractIntroductionInjury mechanisms for Whiplash associated disorders (WAD), caused by rear-end car accidents, are not fully understood. Previous studies have demonstrated cervical vertebral kinematics are influenced by both cervical spinal alignment [1-2] and interaction between thoracolumbar spine and seatback [3]. However, whole spinal alignment has not been well analysed for car occupants [4], despite its importance for WAD-injury mechanisms. Therefore, our aim is to investigate representative whole spinal alignments for male and female occupants.MethodsThe spinal column was scanned for eight female and seven male subjects in one occupant posture using an upright open magnetic resonance imaging (MRI) system. The wooden plate seat (seatback angle of 20 degrees) was designed to obtain a seating posture similar to previous rear impact sled tests [5]. The spinal alignment from C2 to sacrum was defined with the centres of the vertebral bodies obtained in the MRI data, and normalised by C2-sacrum length.Spinal alignment patterns were investigated with Multi-Dimensional Scaling (MDS) [6], identifying the two MDS dimensions with largest inter-subject variance. On the 50% probability ellipsoid, four spinal alignments were calculated based on weighted average of all subjects to describe the MDS dimension (Figure1b-e). Average gender specific spinal alignments were estimated at the average point on the distribution map for female and male subjects, separately.ResultsLimiting the MDS to two dimensions captured 87% of total inter-subject variance. The spinal alignments along the two MDS dimension are illustrated in Figures 1b and c with minor differences along the 2nd MDS dimension. Variance along the 1st MDS dimension, shifted from a slightly kyphotic cervical and less-kyphotic thoracolumbar spine to a lordotic cervical and more pronounced kyphotic thoracolumbar spine. \ua0All female subjects except one had slightly kyphotic cervical and thoracolumbar spine (Figure1b). Male subjects had large variance in spinal alignment, ranging from a slightly kyphotic spine to a lordotic cervical and pronounced kyphotic thoracolumbar spine. Average gender specific spinal alignments were estimated in Figure 1d; a slightly kyphotic or almost straight cervical and less-kyphotic thoracolumbar spine for females, and a lordotic cervical and more pronounced kyphotic thoracolumbar spine for males.DiscussionThere was a prominent relationship showing that cervical lordosis occurred together with pronounced thoracolumbar kyphosis. This was reflected in the estimated average gender specific spinal alignments. This study showed substantial difference in spinal alignment between males and females, with smaller variance for female subject than male subjects. These differences may explain some of the difference in WAD injury risk seen in real-world data.AcknowledgementsJSPS KAKENHI 16KK0137.\ua0References1. Maiman(2002). Neurosurgery, 97:57-62.2. Stemper(2005). J Biomech, 38(6):1313-1323.3. Sato(2010). IRCOBI, p41-58.4. Chabert(1998). ESV, p2072-2079.5. Ono(2006). IRCOBI, p103-113.6. Cox(2000). Multidimensional Scaling.Conference website: www.wcb2018.co

NMR-spectrophotometer integrated device to monitor neuronal activity

科学研究費補助金研究成果報告書研究種目: 基盤研究(B)研究期間: 1999～2000課題番号: 11694262研究代表者: 犬伏 俊郎（滋賀医科大学・分子神経科学研究センター・教授）研究分担者: 森川 茂広（滋賀医科大学・分子神経科学研究センター・助教授）研究分担者: 椎野 顯彦（滋賀医科大学・医学部・講師