Moriyama M.,Osaka Institute of Technology |
Kubota S.,Industrial Technology Center Of Okayama Prefecture |
Tashiro H.,Seirei Sakura Citizen Hospital |
Tonami H.,Osaka Institute of Technology
Journal of Artificial Organs | Year: 2011
Chronic venous insufficiency (CVI) remains a major health problem worldwide. Direct venous valve surgical repair and venous segment transplantation are clinical options; however, they are highly invasive procedures. The objectives of this study were to fabricate prosthetic venous valves (PVVs) by electrospinning, for percutaneous treatment of CVI, and evaluate their hydrodynamic characteristics in vitro at the same locations and under the same flow conditions. The PVVs consisted of polyurethane fiber scaffolds attached to a cobalt-chromium stent. PVVs with two different valve-leaflet configurations were compared: biomimetic PVV (bPVV) and open PVV (oPVV). A balloon catheter was used to implant the devices in a poly(vinyl chloride) tube and the column outlet was set at a height of 100 cm above the test valve to simulate the elevation of the heart above a distal vein valve while standing; 50 wt% glycerin solution was used as the test fluid. The devices were evaluated for antegrade flow, effect of ankle flexion, and stagnation zones around the valve leaflets. During sudden hydrostatic backpressure, little leakage and constant peripheral pressure were observed for the devices; under forward pulsatile pressure of 0-4 mmHg, to simulate the effect of breathing, the oPVV had a higher flow rate than the bPVV. With regard to the effect of ankle flexion, the oPVV was functionless. Moreover, the stagnation zone around the oPVV valve leaflets was larger than that around the bPVV valve leaflets. These results suggest that the bPVV would be clinically suitable for percutaneous treatment of CVI. © 2011 The Japanese Society for Artificial Organs.
Takebe T.,Yokohama City University |
Koike N.,Seirei Sakura Citizen Hospital |
Sekine K.,Yokohama City University |
Enomura M.,Yokohama City University |
And 4 more authors.
Transplantation Proceedings | Year: 2012
Background: One of the major obstacles in regenerating thick, complex tissues such as the liver is their need for vascularization, which is essential to maintain cell viability during tissue growth and to induce structural organization. Herein, we have described a method to engineer a functional human vascular network. Methods: Enhanced green fluorescence protein-labeled human umbilical vein endothelial cells (GFP-HUVECs) were cocultivated with kusabira orange-labeled human mesenchymal stem cells (KO-hMSCs) inside a collagen/fibronectin matrix. Premature vascular network formation was visualized by fluorescence microscopy imaging. Furthermore, constructs prevascularized in vitro were implanted into a transparency window in immunodeficient mice. Results: Following several days of cultivation, GFP-HUVECs formed vessel-like structures that were stabilized by pericytes differentiated from KO-hMSCs. After implantation in vivo, the patency of human vascular structures was proved by rhodamine dextran infusion. These functional vascular structures remained for over 2 months. Discussion: Vascularization is the key challenge to organ generation. We successfully generated human vascular networks inside a matrix. Integration of parenchymal cells using our engineering technique should facilitate future efforts to reconstitute vascularized human organ systems in vitro. © 2012 Elsevier Inc.
Kotani T.,Seirei Sakura Citizen Hospital
BMJ case reports | Year: 2014
Migration of neurogenic spinal tumours is uncommon. However, such possible mobility should be kept in mind during surgery for neurogenic tumours whenever the lesion is not found at the anticipated level. Conventional static imaging techniques, such as myelography and MRI, have not documented dynamic motion of tumours. A 12-year-old boy was diagnosed with a neurogenic spinal tumour in the thoracolumbar region. To assess the migratory tendency of the tumour, cine MRI was performed to acquire dynamic images under postural change. Cine MRI showed that the tumour migrated up to the lower part of the T12 vertebra from the upper part of the L1 vertebra during a change in spinal posture from cervical flexion to extension. The tumour was completely removed and histological examination revealed the tumour to be an ependymoma. Cine MRI is useful for dynamically and non-invasively assessing the migratory tendency of spinal tumours.
Mori K.,Seirei Sakura Citizen Hospital
Clinical Nephrology | Year: 2010
Orally-administered steroids often induce osteonecrosis of the femoral head. In cases of Perthes disease, osteonecrosis of the femoral head occurs in children due to an unknown cause. Our subject was a 4-year-old boy who had to be given large amounts of steroids because of frequently relapsing nephrotic syndrome (FRNS) developed after the onset of Perthes disease. One month earlier, he would limp with his right leg, but his radiographs were normal. Later, facial edema appeared and he was brought to our hospital with heavy proteinuria. He was diagnosed with NS and prescribed prednisolone for 2 months. As he would limp occasionally during the treatment, he had an orthopedic examination at our hospital, and shrinkage of the right femoral head was disclosed. Perthes disease was diagnosed on the basis of his MRI and clinical history. Meanwhile, NS relapsed twice over a half year, and he was diagnosed as having FRNS. Cyclophosphamide was administered for 12 weeks. Four years later, MRI indicated that the femoral head slowly improved and he was able to walk without prosthetic support. These results suggest that in the course of healing from Perthes disease, the conventional method of using prednisolone has little impact on the femoral head. ©2010 Dustri-Verlag Dr. K. Feistle.
Watanabe K.,Keio University |
Uno K.,Kobe medical center |
Suzuki T.,Kobe medical center |
Kawakami N.,Meijo Hospital |
And 12 more authors.
Spine | Year: 2013
STUDY DESIGN.: A retrospective multicenter study. OBJECTIVE.: To identify risk factors for postoperative complications associated with growing-rod (GR) surgery for early-onset scoliosis (EOS). SUMMARY OF BACKGROUND DATA.: Results and complications of GR surgery for EOS have not been adequately studied. METHODS.: We evaluated clinical and radiographical results from 88 patients with EOS who underwent GR surgery in 12 spine centers in Japan. The mean age at the time of initial surgery was 6.5 ± 2.2 years (range, 1.5-9.8 yr) and the mean follow-up period was 3.9 ± 2.6 years (range, 2.0-12.0 yr). Risk factors for postoperative complications were analyzed using binomial multiple logistic regression analysis. We considered the potential factors of sex, age, number of rod-lengthening procedures, whether a pedicle screw foundation was used, the uppermost level of the proximal foundation and lowermost level of the distal foundation, Cobb angles of the proximal thoracic, main thoracic, and lumbar curves, and the kyphosis angles in the proximal, main thoracic, thoracolumbar, and lumbar spine. Kaplan-Meier analysis was used to determine the complication-free survival rate of GR surgery as a function of the number of surgical procedures. RESULTS.: Complications affected 50 of the patients (57%) and were associated with 119 of 538 surgical procedures, with 86 implant-related failures (72%), 19 infections (16%), 3 neurological impairments (3%), and 11 other complications. The most frequent implant-related failure was dislodged implant (71%) and 95% of the dislodgements occurred at the proximal foundation. Kaplan-Meier analysis demonstrated a linear decrease in complication-free rates as the number of rod-lengthening procedures increased. Binomial multiple logistic regression analysis found the following significant independent risk factors: 6 or more rod-lengthening procedures (odds ratio [OR], 6.534), an increase of every 20 in the proximal thoracic Cobb angle (OR, 3.091), and an increase of every 25 in the lumbar lordosis angle (OR, 2.607) in the preoperative condition. CONCLUSION.: Increases in the upper thoracic scoliotic curve, thoracic kyphosis, and number of rod-lengthening procedures are positively associated with an increased risk of complications after GR surgery for EOS.Level of Evidence: 4 © 2013, Lippincott Williams & Wilkins.