Publications by authors named "Kotaro Nishi"

Chronic complete spinal cord injury (SCI) is difficult to treat because of scar formation and cavitary lesions. While human iPS cell-derived neural stem/progenitor cell (hNS/PC) therapy shows promise, its efficacy is limited without the structural support needed to address cavitary lesions. Our study investigated a combined approach involving surgical scar resection, decellularized extracellular matrix (dECM) hydrogel as a scaffold, and hNS/PC transplantation.

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Hepatocyte transplantation (HCT) is a potential bridging therapy or an alternative to liver transplantation. Conventionally, single-cell hepatocytes are injected via the portal vein. This strategy, however, has yet to overcome poor cell engraftment and function.

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Reconstruction of the biliary system is indispensable for the regeneration of transplantable liver grafts. Here, we report the establishment of the first continuous three-dimensional biliary system scaffold for bile acid excretion using a novel method. We confirmed the preservation of the liver-derived extracellular matrix distribution in the scaffold.

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Drug-induced liver fibrosis models are used in normal and immunosuppressed small animals for transplantation and regenerative medicine to improve liver fibrosis. Although large animal models are needed for pre-clinical studies, they are yet to be established owing to drug sensitivity in animal species and difficulty in setting doses. In this study, we evaluated liver fibrosis by administering thioacetamide (TA) to normal microminipig and thymectomized microminipig; 3 times for 1 week (total duration: 8 weeks).

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Soluble guanylate cyclase (sGC) stimulator riociguat is a relatively novel therapeutic agent for pulmonary hypertension (PH) in human medicine. Riociguat induces endothelium-independent pulmonary artery (PA) relaxation by directly activating the sGC-cyclic guanosine-3',5'-monophosphate (cGMP) pathway in muscle cells. Although riociguat may be effective in the treatment of dogs with refractory PH, basic studies on its clinical application in veterinary medicine are lacking.

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Human induced pluripotent stem cells (hiPSCs) are a promising cell source for elucidating disease pathology and therapy. The mass supply of hiPSC-derived cells is technically feasible. Carriers that can contain a large number of hiPSC-derived cells and evaluate their functions in vivo-like environments will become increasingly important for understanding disease pathogenesis or treating end-stage organ failure.

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It has not been considered that nephrons regenerate in adult mammals. We present that an organ-derived extracellular matrix in situ induces nephron regeneration in a preclinical model. A porcine kidney-derived extracellular matrix was sutured onto the surface of partial nephrectomy (PN)-treated kidney.

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Unlimited organ availability would represent a paradigm shift in transplantation. Long-term in vivo engraftment and function of scaled-up bioengineered liver grafts have not been previously reported. In this study, we describe a human-scale transplantable liver graft engineered on a porcine liver-derived scaffold.

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A 7-month-old castrated French bulldog was presented with a left-sided mandibular tumor. The initial tumor biopsy diagnosis was ameloblastoma. The owner brought this dog the Kitasato University Veterinary Teaching Hospital for more detailed examination and treatment.

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In clinical kidney transplantation, the marginal kidney donors are known to develop chronic allograft rejection more frequently than living kidney donors. In our previous study, we have reported that the hydrogen gas-containing organ preservation solution prevented the development of acute injuries in the kidney of the donor after cardiac death by using preclinical miniature pig model. In the present study, we verified the impact of hydrogen gas treatment in transplantation with the optimal immunosuppressive protocol based on human clinical setting by using the miniature pig model.

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Chronic kidney disease leads to high morbidity rates among humans. Kidney transplantation is often necessary for severe symptoms; however, options for new curative treatments are desired because of donor shortage. For example, it has been established that the kidneys can efficiently generate urine after transplantation of the metanephros, ureter, and bladder as a group.

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Purpose: Recent advances in ultrasonography have increased prenatal diagnosis of biliary atresia (BA) and choledochal cyst (CC). These conditions are not easy to distinguish before or just after birth. This study investigated diagnostic and therapeutic problems in prenatal diagnosis of BA and CC.

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Purpose: This study aimed to assess outcomes of liver transplantation (LTx) in patients with biliary atresia (BA).

Methods: The Kasai procedure was performed for 358 patients at Tohoku University Hospital between January 1955 and December 2013; 64 (17.9%) required LTx.

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Purpose: We elucidated the life-threatening risk factors for intestinal failure (IF) and characterized the role of intestinal transplantation (ITx) in affected patients.

Methods: We conducted a retrospective review of 38 patients with short bowel (SB) and 19 with motility disorders (MD). The SB patients were divided into three categories according to the length of their residual small bowel and the presence of the ileocecal valve.

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Purpose: We reevaluated the impact of age at Kasai operation on the short- and long-term outcomes of type III biliary atresia (BA).

Patients And Methods: From 1953 to 2009, 242 patients with type III BA underwent Kasai operation at ages ranging between 12 and 421 days (average, 79.7 days).

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While most long-term survivors of biliary atresia lead lives of good quality, some patients experience late complications. Cholangitis is a common complication even among 20-year survivors including some who develop ongoing liver dysfunction. Portal hypertension is another late complication.

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A 14-yr-old boy with total parenteral nutrition-dependent short-bowel syndrome associated with hypoganglionosis underwent the LR-IT by using a 150 cm segment of distal ileum taken from a healthy donor. The graft vessels were connected to infrarenal aorta and inferior vena cava. The immunosuppressive regimen consisted of daclizumab, tacrolimus, and steroid.

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Background/purpose: A prototype of a 3-mm ultrasonically activated trocar system supplied by Olympus Corporation was evaluated experimentally in terms of its utility and safety.

Methods: Three piglets with an average weight of 12 kg were used. A pneumoperitoneum was created by Hasson's technique.

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This article describes an implantable artificial anal sphincter using shape memory alloys and its in vivo assessment in porcine models. The new design was developed as a low invasive prosthesis with a simple structure to solve the problem of severe fecal incontinence in patients with hypoplastic sphincters or without anal sphincters and especially for ostomates. The artificial anal sphincter consists of two shape memory alloy (SMA) plates as the main functional parts to perform two basic functions when the SMA artificial sphincter is fitted around intestines (i.

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Background/purpose: The authors created a new artificial anal sphincter using a shape memory alloy (AS-SMA) to treat fecal incontinence and evaluated its validity.

Methods: AS-SMA consists of 2 Ti-Ni plates to sandwich the intestine and generates a pressure of 55 mm Hg at its resting position. With the electric power supply, the 2 metals bend to form an almondlike shape making a maximum gap of 33 mm between each other at the temperature of 55 degrees C.

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