Soichi Ohta
Kyoto University
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Featured researches published by Soichi Ohta.
Scientific Reports | 2015
Koji Saihara; Yukihiro Yoshimura; Soichi Ohta; Akio Shimizu
The varying states of water confined in the nano-domain structures of typical room temperature ionic liquids (ILs) were investigated by 1H NMR and by measurements of self-diffusion coefficients while systematically varying the IL cations and anions. The NMR peaks for water in BF4-based ILs were clearly split, indicating the presence of two discrete states of confined water (H2O and HOD). Proton and/or deuterium exchange rate among the water molecules was very slowly in the water-pocket. Notably, no significant changes were observed in the chemical shifts of the ILs. Self-diffusion coefficient results showed that water molecules exhibit a similar degree of mobility, although their diffusion rate is one order of magnitude faster than that of the IL cations and anions. These findings provide information on a completely new type of confinement, that of liquid water in soft matter.
Journal of Brachial Plexus and Peripheral Nerve Injury | 2014
Ryosuke Kakinoki; Ryosuke Ikeguchi; Scott Fm Dunkan; Ken Nakayama; Taiichi Matsumoto; Soichi Ohta; Takashi Nakamura
Background There have been several reports that partial ulnar transfer (PUNT) is preferable for reconstructing elbow flexion in patients with upper brachial plexus injuries (BPIs) compared with intercostal nerve transfer (ICNT). The purpose of this study was to compare the recovery of elbow flexion between patients subjected to PUNT and patients subjected to ICNT. Methods Sixteen patients (13 men and three women) with BPIs for whom PUNT (eight patients) or ICNT (eight patients) had been performed to restore elbow flexion function were studied. The time required in obtaining M1, M3 (Medical Research Council scale grades recovery) for elbow flexion and a full range of elbow joint movement against gravity with the wrist and fingers extended maximally and the outcomes of a manual muscle test (MMT) for elbow flexion were examined in both groups. Results There were no significant differences between the PUNT and ICNT groups in terms of the age of patients at the time of surgery or the interval between injury and surgery. There were significantly more injured nerve roots in the ICNT group (mean 3.6) than in the PUNT group (mean 2.1) (P = 0.0006). The times required to obtain grades M1 and M3 in elbow flexion were significantly shorter in the PUNT group than in the ICNT group (P = 0.04 for M1 and P = 0.002 for M3). However, there was no significant difference between the two groups in the time required to obtain full flexion of the elbow joint with maximally extended fingers and wrist or in the final MMT scores for elbow flexion. Conclusions PUNT is technically easy, not associated with significant complications, and provides rapid recovery of the elbow flexion. However, separation of elbow flexion from finger and wrist motions needed more time in the PUNT group than in the ICNT group. Although the final mean MMT score for elbow flexion in the PUNT group was greater than in the ICNT group, no statistically significant difference was found between the two groups.
Journal of the Physical Society of Japan | 2007
Haruhiro Hiraka; Soichi Ohta; S. Wakimoto; Masaaki Matsuda; K. Yamada
Neutron scattering experiments were carried out to explore Ni-impurity effects on static spin correlations in La 2- x Sr x CuO 4 in the vicinity of the superconductor-insulator boundary where both parallel and diagonal spin-density modulations (SDMs) coexist at low temperature. Dilute Ni substitution completely destroys the bulk superconductivity and alters well-defined incommensurate peaks of Ni-free SDMs into a single broad peak at (π,π). As the Ni concentration ( y ) reaches ∼ x , the magnetic diffuse scattering is transformed to an intense sharp Bragg peak, corresponding to a three-dimensional antiferromagnetic (AF) order in bulk. T N of such Ni-induced AF order depends on x and appears to disappear at x ∼0.1. A simplified cross section for the Q spectra taking into account the orthorhombic domain structure reproduces the Ni-impurity effect on the static spin correlations well, which results in a decreasing incommensurability of both types of SDMs. These effects are approximately ascribed by a reducti...
Hand Surgery | 2013
Ryosuke Kakinoki; Soichi Ohta; Takashi Noguchi; Yukitoshi Kaizawa; Hiromu Itoh; Scott F.M. Duncan; Shuichi Matsuda
PURPOSE To report the outcomes of mallet fractures treated with our modified tension band wiring technique. METHODS Eleven men and two women (mean age; 33 years) with mallet fractures in which happened more than five weeks before surgery, or with fracture fragments involving more than 2/3 or less than 1/3 of the distal phalanx articular surface or with previous surgical intervention, were subjected to this study. The fracture fragment was fixed with a modified tension band wiring technique using a stainless steel wire and an injection needle. RESULTS All patients achieved bone union in nine weeks in average. All patients had no pain except one with mild pain. No patient showed a gap or step-off greater than 1 mm. CONCLUSIONS Our tension band wiring technique can be used regardless of the size of the dorsal fracture fragment or the interval between injury and surgery.
Journal of Brachial Plexus and Peripheral Nerve Injury | 2014
Ken Nakayama; Ryosuke Kakinoki; Ryosuke Ikeguchi; Tomoyuki Yamakawa; Soichi Ohta; Satoshi Fujita; Takashi Noguchi; Scott F.M. Duncan; Suong-Hyu Hyon; Takashi Nakamura
Background In our previous study, allogeneic-transplanted peripheral nerve segments preserved for one month in a polyphenol solution at 4°C could regenerate nerves in rodents demonstrated the same extent of nerve regeneration as isogeneic fresh nerve grafts. The present study investigated whether the same results could be obtained in a canine model. Methods A sciatic nerve was harvested from a male beagle dog, divided into fascicules of < 1.5 mm diameter, and stored in a polyphenol solution (1 mg/ml) for one month at 4°C. The nerve fascicles were transplanted into 10 female beagle dogs to bridge 3-cm right ulnar nerve gaps. In the left ulnar nerve in each dog, a 3-cm nerve segment was harvested, turned in the opposite direction, and sutured in situ. Starting one day before transplantation, the immunosuppressant FK506 was administered subcutaneously at doses of 0.1 mg/kg daily in four dogs (PA0.1 group), 0.05 mg/kg daily in four dogs (PA0.05 group), or 0.05 mg/kg every other day in two dogs (PA0.025 group). Twelve weeks after surgery, electrophysiological and morphological studies were performed to assess the regeneration of the right and left ulnar nerves. The data for the right ulnar nerve were expressed as percentages relative to the left ulnar nerve. Polymerase chain reaction (PCR) was used to identify the sex-determining region of the Y-chromosome (Sry) and β-actin to investigate whether cells of donor origin remained in the allogeneic nerve segments. FK506 concentration was measured in blood samples taken before the animals were killed. Results The total myelinated axon numbers and amplitudes of the muscle action potentials correlated significantly with the blood FK506 concentration. Few axons were observed in the allogeneic-transplanted nerve segments in the PA0.025 group. PCR showed clear Sry-specific bands in specimens from the PA0.1 and PA0.05 groups but not from the PA0.025 group. Conclusions Successful nerve regeneration was observed in the polyphenol-treated nerve allografts when transplanted in association with a therapeutic dose of FK506. The data indicate that polyphenols can protect nerve tissue from ischemic damage for one month; however, the effects of immune suppression seem insufficient to permit allogeneic transplantation of peripheral nerves in a canine model.
Synthetic Communications | 2004
Hideyuki Suzuki; Soichi Ohta; Chiaki Kuroda
Abstract γ‐Substituted‐β‐(ethoxycarbonyl)allylsilanes were synthesized via a Peterson olefination using ethyl 2,3‐bistrimethylsilylpropanoate.
Cell Transplantation | 2017
Yukitoshi Kaizawa; Ryosuke Kakinoki; Ryosuke Ikeguchi; Soichi Ohta; Takashi Noguchi; Hisataka Takeuchi; Hiroki Oda; Hirofumi Yurie; Shuichi Matsuda
Cells, scaffolds, growth factors, and vascularity are essential for nerve regeneration. Previously, we reported that the insertion of a vascular bundle and the implantation of bone marrow-derived mesenchymal stem cells (BM-MSCs) into a nerve conduit promoted peripheral nerve regeneration. In this study, the efficacy of nerve conduits containing a vascular bundle, BM-MSCs, and thermally decellularized allogenic nerve matrix (DANM) was investigated using a rat sciatic nerve model with a 20-mm defect. Lewis rats were used as the sciatic nerve model and for the preparation of BM-MSCs, and Dark Agouti rats were used for the preparation of the DANM. The revascularization and the immunogenicity of the DANM were investigated histologically. The regeneration of nerves through nerve conduits containing vessels, BM-MSCs, and DANM (VBD group) was evaluated based on electrophysiological, morphometric, and reinnervated muscle weight measurements and compared with that of vessel-containing conduits that were implanted with BM-MSCs (VB group). The DANM that was implanted into vessel-containing tubes (VCTs) was revascularized by neovascular vessels that originated from the inserted vascular bundle 5–7 days after surgery. The number of CD8+ cells found in the DANM in the VCT was significantly smaller than that detected in the untreated allogenic nerve segment. The regenerated nerve in the VBD group was significantly superior to that in the VB group with regard to the amplitude of the compound muscle action potential detected in the pedal adductor muscle; the number, diameter, and myelin thickness of the myelinated axons; and the tibialis anterior muscle weight at 12 and 24 weeks. The additional implantation of the DANM into the BM-MSC-implanted VCT optimized the axonal regeneration through the conduit. Nerve conduits constructed with vascularity, cells, and scaffolds could be an effective strategy for the treatment of peripheral nerve injuries with significant segmental defects.
British Journal of Haematology | 2015
Soichi Ohta; Yuho Najima; Jun Imamura
A 46-year-old man with Philadelphia chromosome-positive acute lymphoblastic leukaemia achieved a complete molecular response with induction therapy including imatinib. However, imatinib was discontinued because of persistent nausea and severe oedema of both lower limbs. He received consolidation therapy, which comprised high-dose cytarabine, high-dose methotrexate and methylprednisolone and, subsequently, dasatinib. On day 9, 6 days after starting dasatinib, he developed melaena and prolonged anaemia requiring the transfusion of 12 units of red blood cells during the following 2 weeks. Upper gastrointestinal endoscopy on day 23 revealed oozing from scattered mucosal erosions in the gastric antrum with a ‘watermelon appearance’ (left), which was indicative of gastric antral vascular ectasia (GAVE). Because of the suspicion of drug-induced GAVE, dasatinib was discontinued and his symptoms improved soon after drug cessation. The complete resolution of GAVE was confirmed by a follow-up upper gastrointestinal endoscopy on day 42 (right). Gastric antral vascular ectasia accounts for up to 4% of all non-variceal upper gastrointestinal bleeding and is associated with underlying chronic diseases, particularly cirrhosis and autoimmune diseases. Although rare, some drugs, including imatinib, have also been reported to cause GAVE. Our patient demonstrates that other tyrosine kinase inhibitors can also be responsible. Awareness of this rare complication is important because GAVE can sometimes cause severe, acute bleeding in patients treated with tyrosine kinase inhibitors.
Journal of Hand Surgery (European Volume) | 2011
Ryosuke Kakinoki; Ryosuke Ikeguchi; Soichi Ohta; Scott F.M. Duncan; Satoshi Fujita; Takashi Noguchi
A boy was born with a right duplicated thumb (Wassel type 6) and a left radial club hand (type 3) associated with a hypoplastic thumb (type 3B). He underwent surgical centralization of the left wrist when he was 13 months old. At age 38 months, he underwent reconstruction of the carpometacarpal joint of the hypoplastic left thumb. This procedure involved transplantation of the radial ray of the right duplicated thumb to the base of the left thumb. When he was 6 years old, the patient underwent an abductor digiti minimi muscle transfer to create opposition for the left thumb and deepening of the first web. At the final follow-up, he could grasp items in the first web space and pick up small items between the thumb and other digits of the left hand. The treatment represents a method of using otherwise discarded tissues for effective reconstruction.
Carbohydrate Research | 2006
Akihiro Ishiwata; Soichi Ohta; Yukishige Ito