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H Tsumura

Publications and source records attributed to H Tsumura.

At least 19 recordsLinked to original sources
PubMed2006

Cooperation of oncogenic K-ras and p53 deficiency in pleomorphic rhabdomyosarcoma development in adult mice.

Human rhabdomyosarcomas (RMSs) frequently demonstrate genetic alterations in ras and p53. To investigate their possible involvement in the tumorigenesis, we generated a knock-in mouse line with oncogenic K-ras, conditionally expressed by Cre/LoxP system on a background of p53 alteration. Electroporation of Cre expression vector in skeletal muscle tissues resulted in the generation of tumor in adults with tumor incidences of 100% at 10 weeks and 40% at 15 weeks, in p53(-/-) and p53(-/+) backgrounds, respectively. The tumor histology was pleomorphic RMS with characteristic bizarre giant cells, positive for desmin and alpha-sarcomeric actin and exhibiting remarkable increase in total and phosphorylated extracellular signal-regulated protein kinase (ERK)1 and ERK2. Loss of the wild-type p53 was detected in K-rasG12V-expressed tumors of p53(-/+) mice. Early lesions 3 weeks after electroporation consisted of proliferating populations of myogenic progenitors, including stem cells positive for ScaI antigen, immature cells positive for desmin and neural cell adhesion molecule-positive myotubes. Thus, cooperation of oncogenic K-ras and p53 deficiency resulted in the development of pleomorphic RMS in adult mice, providing a useful mouse model for further detailed studies.

Animals↗
PubMed2005

Three-dimensional finite element analysis of unicompartmental knee arthroplasty--the influence of tibial component inclination.

Aseptic loosening and failure of a tibial component are recognized problems in unicompartmental knee arthroplasty (UKA). Excessive stress on the supporting cancellous bone is thought to contribute to the loosening and failure. Of factors that could influence supporting cancellous bone stresses, we focused on the inclination of a unicompartmental tibial component by analyzing the effect of coronal plane and sagittal plane inclination. Detailed geometrically accurate, three-dimensional finite element models were constructed from computed tomography (CT) data of a typical adult male proximal tibia. The material properties for the models were obtained directly from the CT data to simulate the inhomogeneous distribution of cancellous bone properties. Placing the component in slight valgus inclination in the coronal plane reduced the cancellous bone stresses. Posterior inclination in the sagittal plane caused a moderate increase in the stresses. Our results suggest that slight valgus inclination of a UKA tibial component may be preferable to varus or square inclination in the coronal plane. An excessive posterior slope of a tibial component should be avoided.

Arthroplasty, Replacement, Knee↗
PubMed2005

Does the self-centering mechanism of bipolar hip endoprosthesis really work in vivo?

PURPOSES: To examine radiographically the component motion in a bipolar prosthesis and to determine whether the self-centering mechanism really works in vivo. METHODS: 38 patients with 41 bipolar hip endoprostheses (30 for coxarthrosis and 11 for osteonecrosis of femoral head) were included in this study. Two radiographs of each case were taken to evaluate the self-centering mechanism. The first anteroposterior radiograph of both hip joints was taken at the maximum abduction while the patient standing on the endoprosthetic leg. The second radiograph was taken after the patient returned to neutral position while standing on 2 legs. In the present study, the order in which the radiographs were taken differed from previously reported studies. The radiographs were analysed using the method similar to that of Drinker and Murray. The adductive motion from abduction to a neutral position is within the range of inner bearing oscillation. RESULTS: The outer head alignment changed from 23 degrees to 12 degrees in the patients with osteonecrosis. However, the valgus position of the outer head (36 degrees) remained unchanged in the patients with coxarthrosis standing on 2 legs in the neutral position. CONCLUSION: The self-centering mechanism of the bipolar endoprosthesis functioned in the patients with osteonecrosis, but did not work in the coxarthrosis group.

Arthroplasty, Replacement, Hip↗
PubMed2005

Debridement and continuous irrigation for the treatment of pyogenic arthritis caused by the use of intra-articular injection in the osteoarthritic knee: indications and outcomes.

PURPOSE: To discuss the indications and therapeutic outcomes of synovectomy, debridement, and continuous irrigation for the treatment of pyogenic arthritis caused by intra-articular injection used in the treatment of osteoarthritis of the knee. METHODS: Records of 41 patients with infectious arthritis of the knee who presented to our hospital from 1981 were reviewed. 11 of them had a history of intra-articular injection. They underwent synovectomy, debridement, and continuous irrigation using a Salem double-lumen tube after confirmation that one side of the femorotibial joint cartilage was basically healthy. RESULTS: The infection was successfully treated in 9 of the 11 patients. Of these 9 patients, one died after 3 years and 2 underwent total knee arthroplasty after 3 and 8 years. The remaining 6 patients were followed up for 5 to 15 years. Five of them had deteriorating arthropathy, and the condition was unchanged in the others. Two of these 6 patients had pain while walking, and their Japanese Orthopaedic Association scores were 70. The remaining 4 had good knee function and reduction of pain, with a mean Japanese Orthopaedic Association score of 91 and a mean range of motion of 131 degrees. CONCLUSION: Arthrodesis is frequently considered the treatment for osteoarthritis if the joint destruction has affected the weight-bearing surface. However, in our experience, even when inflammatory granulation develops in the cartilage surface of one side of the femorotibial joint, good results can still be obtained by synovectomy, debridement, and continuous irrigation. After the pyogenic arthritis has subsided, if osteoarthritis has advanced and bowleg has exacerbated, further treatment options are available, such as tibial resection and even joint replacement. Continuous irrigation should be considered a feasible treatment option for pyogenic arthritis.

Adrenal Cortex Hormones↗
PubMed2003

Successful laparoscopic Ladd's procedure and appendectomy for intestinal malrotation with appendicitis.

We successfully performed a laparoscopic Ladd's procedure and an appendectomy in a 15-year-old girl with intestinal malrotation and appendicitis. She had tenderness and rebound pain in the umbilicus and left lower abdominal quadrant. Blood analysis revealed a moderate inflammatory response. Enhanced computerized tomography (CT) scanning revealed a whirl-like pattern and a superior mesentric vein (SMV) rotation sign in the mesentry of the small intestine. A swollen appendix was seen just below the umbilicus. An upper gastrointestinal (GI) radiological series confirmed agenesis of Treitz's arch. The patient was diagnosed as having a nonrotation type of malformation accompanied by acute appendicitis. She underwent a laparoscopic Ladd's procedure, an appendectomy, peritoneal lavage, and drainage. The technique for this procedure and its effectiveness are briefly discussed.

Adolescent↗
PubMed2002

Production of active bovine cathepsin C (dipeptidyl aminopeptidase I) in the methylotrophic yeast Candida boidinii.

The heterologous production of active bovine cathepsin C (CTC; dipeptidyl aminopeptidase I) was investigated. Attempts to express CTC in Escherichia coli were hampered by formation of inclusion bodies that were partially degraded. To overcome this impediment, secretion of recombinant CTC was attempted in the methylotrophic yeast Candida boidinii. A DNA fragment encoding bovine procathepsin C was synthesized based on preferred codon usage in C. boidinii and placed downstream of the C. boidinii proteinase A signal sequence resulting in secretion of active CTC into the culture medium. The gene was expressed under the control of the methanol-inducible formate dehydrogenase gene promoter. Production levels were significantly improved by using a protease-deficient strain, changing medium composition, and by lowering the temperature of induction. When the recombinant C. boidinii was grown for 90 h in a jar-fermenter, active CTC was secreted with a yield of up to approximately 12 mg/l.

Amino Acid Sequence↗
PubMed2002

An assessment of histopathological criteria for infection in joint arthroplasty in rheumatoid synovium.

Intraoperative frozen section is reported to be a reliable means of identifying occult infection for preoperative evaluation of arthroplasty. The aim of this study was to determine whether the reported histopathological criteria--the existence of more than 10 polymorphonuclear cells (PMN) per high-power field--is valuable for determination of infection during the arthroplasty of patients with rheumatoid arthritis (RA). The permanent histological sections of RA synovium were analysed to study the degree of infiltration of PMNs. Furthermore, in order to examine the penetrative distribution of PMNs within the synovial tissues, immunohistochemical staining of PMNs was performed. In addition, the clinical history, from the postoperative period to the present, was investigated in 46 patients (60 joints). The presence of early- and/or late-stage postoperative infection, the development of postoperative fever, the progression of erythrocyte sedimentation rate (ESR) (more than 30 mm per hour) and the changes in CRP (more than 10 mg per litre) were further examined and compared with the histopathological tissue analyses and findings. The results demonstrated the presence of more than five PMNs per high-power field, excluding surface fibrin and inflammatory exudate in at least five separate microscopic fields in 10 joints (16.7%) of nine patients, out of 60 joints of 46 patients, in which no postoperative infection was evident. As to the magnitude of penetrative distribution of PMNs in 10 joints, there was a trend of deepening infiltration among the patients with intensive PMN infiltration. In addition, no development of postoperative fever, CRP or continuous indications of high ESR values were evident in this group. As the existence of more than 10 PMN per high-power field was not absolutely indicative of occult infection, investigation of frozen section during arthroplasty should be carefully managed.

Adult↗
PubMed2002

The effects of tibial component inclination on bone stress after unicompartmental knee arthroplasty.

Unlike the case with total knee arthroplasty, the femorotibial angle (FTA) after unicompartmental knee arthroplasty (UKA) does not directly depend on the inclination of the tibial component when the height of the joint line is maintained. This study analyzed the effects of the inclination of the tibial component in the coronal plane on the contact pressure of the implant-bone surface and the stresses on the proximal tibia. A two-dimensional, coronal plane model of the proximal tibia was subjected to finite-element analysis. Sixteen patterns of finite-element models of equal FTA were developed in which the inclination of tibial components ranged from 5 degrees valgus to 10 degrees varus in increments of 1 degrees. Stress concentration at the proximal medial diaphyseal cortex gradually increased as the inclination changed from valgus to varus. Maximum contact pressure on the metal-bone interface similarly changed and shifted from the lateral edge to the medial edge of the implant as the inclination changed to varus. It was found that even without changing FTA, the inclination of the tibial component might affect stress concentration and contact pressure in the proximal tibia after UKA. The results suggested that slight valgus inclination of the tibial component might be preferable to varus and even to 0 degrees (square) inclination so far as the stress distribution is concerned.

Arthroplasty, Replacement, Knee↗
PubMed2002

NOS and COX isoforms and abnormal microvessel responses to CO2 and H+ in hyperoxia-injured lungs.

The aim of the present study was to compare microvessel responses to hypercapnic and isocapnic acidosis in hyperoxia-injured lungs and to assess the role of constitutive and inducible forms of nitric oxide synthase (NOS) and cyclo-oxygenase (COX). Real-time confocal luminescence microscopy was used to measure changes in the diameter of acinar arterioles, venules and capillaries in response to stimulation with hypercapnic and isocapnic acidosis in isolated rat lungs injured by 90% oxygen exposure for 48 h. Observations were made with and without inhibition of constitutive (endothelial constitutive NOS (ecNOS) and COX-1) and inducible isoforms (iNOS and COX-2) of NOS and COX. Upregulation of NOS was assessed by measuring enzyme levels in lung homogenates by Western blot analysis and enhancement of the COX-related pathway was judged from perfusate concentrations of 6-ketoprostaglandin F1alpha. ecNOS and COX-1, but not iNOS and COX-2, were upregulated in hyperoxia-injured lungs. The nitric oxide produced by ecNOS attenuated COX-1 activity in injured arterioles and venules, but carbon dioxide enhanced it, leading to paradoxical dilatation of these microvessels under hypercapnic conditions with ecNOS inhibition. Although a high hydrogen ion concentration was unnecessary for excitation of COX-1, venule constriction in response to H+ was enhanced by COX-1 inhibition. Constitutive, but not inducible, isoforms of cyclo-oxygenase and nitric oxide synthase play an important role in abnormal microvessel responses to carbon dioxide and hydrogen ions in hyperoxia-injured lungs.

Acidosis, Respiratory↗
PubMed2001

Comparison of ultrasonically activated scalpel versus conventional division for the pancreas in distal pancreatectomy.

PURPOSE: The goal of this study was to compare the benefits and complications of using an ultrasonically activated scalpel and conventional division of the pancreas in patients undergoing a distal pancreatectomy. METHODS: A retrospective review was performed of all patients who underwent distal pancreatectomy at the Department of Surgery, Koshigaya Municipal Hospital. In the ultrasonically activated scalpel (US) group (n = 11), the pancreas was divided using coagulation shears. The stump of the pancreas was left open without parenchymal suturing. In the conventional surgical division (CV) group (n = 20), the pancreas was cut with a knife and the stump was oversewn with interrupted mattress sutures. The main pancreatic duct was ligated in all patients in both groups. The postoperative courses in the two groups were then compared in terms of postoperative serum amylase levels and the incidence of pancreatic fistulas. RESULTS: The postoperative serum amylase levels were significantly lower in the US group than in the CV group (P < 0.01 on the day of operation). The incidence of pancreatic fistulas was also significantly lower in the US group (0%) than in the CV group (30%) (P = 0.04). CONCLUSIONS: The use of the ultrasonically activated scalpel was found to reduce the incidence of pancreatic fistula in distal pancreatectomy. Furthermore, the use of this device without any clamping or parenchymal suturing may reduce the damage to the remnant pancreas.

Aged↗
PubMed2000

Atlantoaxial subluxation associated with ossification of posterior longitudinal ligament of the cervical spine.

STUDY DESIGN: Two case reports. OBJECTIVE: To demonstrate two rare cases of atlantoaxial subluxation associated with ossification of the posterior longitudinal ligament of the cervical spine, in which spastic quadriplegia developed. SUMMARY OF BACKGROUND DATA: There are only two reports of an association of diffuse idiopathic skeletal hyperostosis with atlantoaxial subluxation. This condition often accompanies ossification of the posterior longitudinal ligament of the cervical spine, but there is nothing in the literature about the association of ossification of the posterior longitudinal ligament with atlantoaxial subluxation. METHODS: Clinical and radiographic findings of these two cases were demonstrated. In both cases laminoplasty of the cervical spine was performed with occipitoaxial arthrodesis. RESULTS: The spastic quadriplegia of these two patients caused by myelocompression improved after surgical intervention. CONCLUSION: Ossification of the posterior longitudinal ligament of the cervical spine may cause atlantoaxial subluxation.

Aged↗
PubMed2000

Hepatic resection using the harmonic scalpel.

We describe herein our technique of performing extensive resection of the liver by blunt dissection in combination with excision using a harmonic scalpel. A ball coagulator was inserted at 3-cm intervals along the proposed cutting line in the liver, and the liver parenchyma between these holes was then cut using coagulation shears. Regardless of the condition of the liver, good coagulation and cutting were achieved using the harmonic scalpel without vascular occlusion when dividing the shallow layer of the liver, and no complications in association with the harmonic scalpel, such as postoperative bleeding, bile leakage, or abscess formation at the cut margins, occurred. In the deep layer below the main trunk of the hepatic vein, blunt dissection was used, since it was difficult to achieve sufficient control of bleeding from large vessels using the harmonic scalpel alone. Therefore, when used in combination with other techniques, the harmonic scalpel appears to be an effective device for liver surgery that minimizes bleeding and decreases the vascular clamping time.

Adult↗
PubMed2000

Role of multinuclear cells in granulation tissue in osteomyelitis: immunohistochemistry in 66 patients.

We investigated the origin of multinuclear cells (MNCs) in the granulation tissue in osteomyelitis by immunohistochemical techniques in 66 patients. 12 samples were analyzed for the presence of CD68, cathepsin K, CD11b and tartrate-resistant acid phosphatase (TRAP) activity. Many MNCs were present in the granulation tissue adjacent to a sequestrum. MNCs in contact with the sequestrum were also noted, however, no osteoblasts were found. Immunohistochemically, CD68, cathepsin K and TRAP were strongly expressed in most of the MNCs, while CD11b positive cells were not found. MNCs remote from and in contact with the sequestrum showed the same immunohistochemical features which are characteristic of osteoclasts. Further, MNCs in contact with the sequestrum had originally developed in the granulation tissue and directly infiltrated towards the sequestrum without cell-to-cell interaction with osteoblasts.

Acid Phosphatase↗
PubMed2000

Delayed paraplegia caused by the gradual collapse of an infected vertebra.

A case of delayed paraplegia caused by a gradual and progressive collapse of a vertebra after healing of pyogenic spondylitis is reported. A 73-year-old man was treated for a hematogenously seeded pyogenic spondylitis of the first lumbar vertebra. Magnetic resonance imaging showed a high signal intensity of the involved vertebra and adjacent discs and a paravertebral abscess without disc space narrowing. Eight months after healing of the infection, the patient had muscle weakness and paresthesia of the lower extremities, which gradually increased. The plane radiographs revealed a kyphotic deformity of 36 degrees with a collapse of the first lumbar vertebra.

Abscess↗