Reply Letter to “Cervical Facet Joint Degeneration”

Yasuhiro Takeshima,Ai Okamoto,Shohei Yokoyama,Fumihiko Nishimura,Ichiro Nakagawa,Young-Soo Park,Hiroyuki Nakase 대한척추신경외과학회 2022 Neurospine Vol.19 No.3

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Facet Articular Irregularity Is the Most Relevant Risk Factor for Rapidly Progressive Degenerative Cervical Myelopathy

Yasuhiro Takeshima,Ai Okamoto,Shohei Yokoyama,Fumihiko Nishimura,Ichiro Nakagawa,Young-Soo Park,Hiroyuki Nakase 대한척추신경외과학회 2023 Neurospine Vol.20 No.1

Objective: Facet articular irregularity is associated with rapidly progressive degenerative cervical myelopathy (DCM). However, its significance compared with other known risk factors remains unknown. Therefore, this retrospective study aimed to clarify the potential impact of facet articular irregularity as a risk factor for rapid DCM progression. Methods: This study included 141 consecutive patients with DCM who underwent surgical treatment at our institution. Clinical variables and radiological findings related to DCM progression were collected. Imaging findings were analyzed at the segmental level of myelopathy in each case. The patients were divided into 2 groups based on the presence or absence of rapid DCM progression, and independent risk factors were determined using logistic regression analyses. Results: Overall, 131 patients with a mean age of 63.9 ± 12.6 years were analyzed; 27 patients (20.6%) were classified into the rapid DCM progression group. The mean age was significantly higher in the rapid progression group than in the slow progression group (72.4 ± 9.6 vs. 61.7 ± 12.4, p < 0.001). According to univariate analysis, facet articular irregularity, dynamic segmental translation (≥ 1.6 mm), upper cervical spine involvement above C4–5, history of cerebrovascular events, preceding minor trauma, local lordotic angle (≥ 4.5°), diabetes, hypertension, ligamentum flavum hypertrophy, and age were independent risk factors. Additionally, multivariate analysis showed that facet articular irregularity was the highest risk factor for rapid DCM progression (p = 0.001). Conclusion: Facet articular irregularity is the most clinically significant finding among the known risk factors in patients with rapid DCM progression.

Prevalence and Clinical Impact of Cervical Facet Joint Degeneration on Degenerative Cervical Myelopathy: A Novel Computed Tomography Classification Study

Ai Okamoto,Yasuhiro Takeshima,Shohei Yokoyama,Fumihiko Nishimura,Ichiro Nakagawa,Young-Soo Park,Hiroyuki Nakase 대한척추신경외과학회 2022 Neurospine Vol.19 No.2

Objective: To evaluate cervical facet joint degeneration using a newly developed classification, investigate its prevalence and relationship with cervical degenerative spondylolisthesis, and clarify its clinical significance in patients with degenerative cervical myelopathy (DCM). Methods: This study included 145 consecutive patients with DCM who underwent surgical treatment. Clinical variables and radiological findings were analyzed. A new 6-grade computed tomography (CT) classification for cervical facet joint degeneration was adapted, and its prevalence was evaluated by categorizing the joints into those at responsible and those at nonresponsible spinal segmental levels. We evaluated the association between rapidly progressive myelopathy and the presence of significant facet joint degeneration or spondylolisthesis at the responsible segmental level. Results: Finally, 140 patients with a mean age of 64.1 ± 12.8 years were analyzed. The prevalence of grade 1, 2, 3, 4, 5A, and 5B classification in all facet joints was 72.0%, 9.5%, 10.9%, 4.3%, 2.9%, and 0.4%, respectively. There was a statistically significant difference in the distribution of CT grades between the joints at the responsible and nonresponsible segmental levels (p < 0.001), with a high prevalence of grade 4 or 5B degeneration at the responsible segmental level, reflecting articular irregularity. There was also a statistically significant relationship between rapidly progressive myelopathy and grade 4 or 5B degeneration at the responsible segmental level (p < 0.001), but not between rapidly progressive myelopathy and spondylolisthesis (p = 0.255). Conclusion: This novel CT classification for facet joints deserves additional evaluation in patients with DCM. Abnormal findings on the articular surfaces might be related to the progression of myelopathy.

Direct Micro-joining of Flexible Printed Circuit and Metal Electrode by Pulsed Nd:YAG Laser

Mohd Idris Shah Ismail,Yasuhiro Okamoto,Akira Okada,Yoshiyuki Uno,Kentaro Ueoka 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.

Laser micro-welding has proven to be a very successful tool for micro-joining in the electrical and electronic industries,where the miniaturization, the high strength and the high heat resistance are constantly requested. Recently, a flexible printed circuit (FPC) is expected as a new connection technology between electrical conductors according to the improvements of reliability and controllability with the diversification of the design concept. In this technology, it is required to weld a several tens μm thickness of FPC and a several hundreds μm thickness of metal electrode. This material combination accompanies the difficulty to control the welding phenomenon due to the differences of thermal property and heat capacity. As a good alternative, laser micro-welding has advantages of non-contact tool, low heat distortion and consistent weld integrity. In this study, the overlap welding of thin copper circuit on a polyimide film and a thick brass electrode was experimentally and numerically investigated by using a pulsed Nd:YAG laser. In addition, the shearing stress of overlap welding was evaluated with and without the control of pulse waveform, which can provide a well-directed controlling of the heat input with high energy density. The results showed that a porosity was observed as the major weld defect in the welding process without a pulse control. However, the appropriate controlled laser pulse configuration of micro-welding could remove the weld defects in the molten zone, improve the weld penetration stability and increase the weld strength. The potential benefits of controlled pulse waveform were discussed for the direct laser micro-welding process. It is clarified that the direct laser micro-welding of a thin copper circuit on a polyimide film and a thick brass electrode could be successfully achieved by appropriate controlled pulse waveform and heat input.

Validation of trip-induction system on a treadmill by comparison with a walking lane

Hazuki Miyata,Akiyama Yasuhiro,Yoji Yamada,Shogo Okamoto 제어로봇시스템학회 2019 제어로봇시스템학회 국제학술대회 논문집 Vol.2019 No.10

Trip-related falls, which account for a significant portion of falls by the elderly, often result in serious injury. A method to evaluate fall risk accurately will be increasingly required in the aging society. For this purpose, it is necessary to analyze the natural reaction motion against tripping. We therefore developed a device and method to induce tripping at an arbitrary time during walking on a treadmill. To evaluate the validity of that method, another experiment that induced tripping on a walking lane was conducted. The reaction motions in the two environments were then compared. In this study, we focused on the difference in the preferred walking speed between the ground and the treadmill. The results suggest that the joint patterns during the reaction motion become similar when the subjective velocities, not the physical velocities, become the same for the subject, whereas physical parameters such as the trajectory of the center of mass become similar when the physical velocities match. These results help to understand the reaction motion against tripping and to reproduce the natural reaction motion on the treadmill.

Chemical Approach for the Synthesis of Homogeneous Large Glycoproteins

Shohei Imada,Ryo Okamoto,Masayuki Izumi,Yasuhiro Kajihara 한국당과학회 2012 한국당과학회 학술대회 Vol.2012 No.1

Glycoprotiens are responsible in many biological events. However oligosaccharides covalently attached to these proteins always exhibit heterogeneity. This has been a hindrance to investigate what oligosaccharide structure is essential for the individual biological event. Therefore we have examined the chemical synthesis of several glycoproteins such as cytokines consist of 70 to 166 amino acid residues. [1-3] However, glycoproteins used in the cell-cell communication or immune response exhibit larger molecular weight comparing with those of cytokines we have synthesized. Unfortunately, the synthesis of such large and homogeneous glycoproteins is still far from our current achievements, because we have not established an efficient method for the synthesis of large glycoproteins yet. Native chemical ligation[4] is a powerful method to couple two polypeptide chains through a native amide bond. This ligation takes place between peptide-C-terminal thioester and cysteine at the N-terminal of another peptide. Using this ligation between glycopeptide-thioester synthesized by chemical method and long peptide prepared from E. coli expression, we have examined the synthesis of large glycoprotein. In this presentation, we would discuss the first synthesis of large and homogeneous glycosylpolypeptide chain (25 kDa) consists of over 200 amino acid residues.

Maturational Changes in Binding Capacity of Fowl Sperm to the Epithelium of the Sperm Storage Tubules during Their Passage through the Male Reproductive Tract

Ahammad, Muslah U.,Okamoto, S.,Kawamoto, Yasuhiro,Nakada, T. Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.9

The objective of this study was to examine the binding potential of sperm to the epithelium of the sperm storage tubules (SST) in vitro and in vivo to assess the functional maturation of fowl sperm. Sperm from the testis, epididymis, as well as the proximal, middle and distal vas deferens were incubated in vitro with either the uterovaginal junction (UVJ)- or infundibular tissue containing SST at $39^{\circ}C$ for 30 min. Aliquots of sperm were also artificially inseminated into the uteri of hens, and the UVJ and infundibulum were collected 24 h post artificial insemination (AI). After incubation and AI, tissues were washed to remove loosely adhered sperm and subjected to fluorescence staining with 4', 6-diamidino-2-phenylindole, dihydrochloride (DAPI) for counting the number of bound sperm per 0.25 mm2 of surface area. Sperm from the testis, epididymis, and the three segments of the vas deferens exhibited their differential (p<0.05) binding capacity, which increased gradually from the testicular to distal vas deferens sperm under both in vitro and in vivo conditions. Existing similar trend, sperm, regardless of their source had a lesser affinity to bind to the epithelium of the infundibular SST than to the UVJ-SST. These experimental results suggested that fowl sperm may undergo gradual changes in the process of functional maturation, whereby they gain the ability to bind to the epithelium of the SST during their passage through the male reproductive tract (MRT).

Investigation into Hand Impact Force During Forward Falls on Uneven Terrain

Saeed Abdolshah,Nader Rajaei,Yasuhiro Akiyama,Yoji Yamada,Shogo Okamoto 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.3

Outdoor falls predominantly occur because of environmental factors, such as tripping caused by uneven terrain; as a result, the faller may land on an uneven surface. Forward falls are among the most frequent causes of fractures. Previous investigations concentrated on the evaluation of impact forces acting on the hand/wrist on even terrains; however, further studies are necessary to evaluate the impact force during forward falls on uneven surfaces, which may occur frequently in daily activities. This study investigated the distal/proximal hand impact force during forward falls on even/uneven terrain. A series of fall experiments in which the distal and proximal areas of the hand contacted the ground simultaneously (even surface) or at different times (uneven surface) was conducted. The results showed that the magnitude of the peak impact forces acting on the distal and proximal areas are strongly associated with the terrain shape and the contact timing. Although in all experiments, a significant portion of the impact force was exerted on the proximal area of the hand, the earlier distal-ground contact reduced the peak proximal impact force significantly. The results of this study are beneficial for finding strategies to reduce fall-related injuries and the design of protective gloves and wrist guards to satisfy fracture prevention requirements.

Effect of the relative rotation axis position of the stretching machine and ankle

Yuma SHIRAISHI,Shogo OKAMOTO,Naomi YAMADA,Koki INOUE,Yasuhiro AKIYAMA,Yoji YAMADA 제어로봇시스템학회 2019 제어로봇시스템학회 국제학술대회 논문집 Vol.2019 No.10

At the onset of a stroke, paralysis of the lower leg typically causes a foot deformity called the foot drop. Stretching is an effective technique for physical therapy. An automated stretching machine provides the option to incorporate long-term stretching at home. We have remodeled a commercial foot exerciser to function as a stretching machine for ankle dorsiflexion [1]. It is believed that the rotation axis of such machines should be aligned with the biomechanical axis of the human body, which is the design principle our prototype is based on. However, there have been no studies that have investigated the best position of the axis required to achieve effective stretching. In this study, we evaluated several positions of the machine’s rotation axis in the sagittal plane with respect to the stretching effect and physical burden (safety). The force applied on the foot and ankle dorsiflexion angle were measured during the stretching experiments. We computed the work involved in ankle dorsiflexion and the force not contributing to the dorsiflexion movement, which served as indicators for the stretching effect and potential physical burden, respectively. It was found that the best position of the machine’s rotation axis can be above the ankle.

Synthetic Study of Carbohydrate Binding Domain of Siglec7

Akihisa Otsuki,Ryo Okamoto,Masayuki Izumi,Yasuhiro Kajihara 한국당과학회 2012 한국당과학회 학술대회 Vol.2012 No.1

Sialic acid-binding immunoglobulin-like lectin (Siglec) 7 is one of the sialic acid binding protein that plays an important role in immune system. Siglec 7 is expressed on natural killer cells and displays a unique ligand binding properties comparing to the other members of the Siglec family, specifically binds to  2,8-disialyl residues. The precise structural analysis of Siglec 7 has been already performed, and amino acid residues involved in the ligand binding are reported. In such context, we set out the first total chemical synthesis of Siglec 7 carbohydrate binding domain (CBD) which consists of 127 amino acid residues. Since chemical synthesis can easily introduce unnatural amino acids, we envisioned that we could produce an artificial sialic acid binding lectin based on this chemical synthetic strategy. The synthesis of Siglec 7 CBD was carried out by convergent total chemical synthesis. The whole polypeptide was assembled from 5 peptide segments (Figure), which were synthesized by conventional solid phase peptide synthesis. We applied native chemical ligation (NCL) for the coupling of these segments sequentially from C-terminus, combined with alkylation with haloacetoamide or desulfuration reaction. These reactions can provide pseudo-Gln residue or Ala residue from Cys residues at the ligation sites. Based on these strategies we have successfully obtained the full-length polypeptide of Siglec 7 CBD and currently are investigating the in vitro folding step.