Biomedical subjects

Kensei Nagata

Publications and source records attributed to Kensei Nagata.

27 records · Page 2Linked to original sources

PubMed2003

Fasciitis-like proliferation in the knee joint.

We describe the case of fasciitis-like proliferation in the knee joint in a 52-year-old man. The polypoid lesion developed from the synovial joint capsule around the quadriceps tendon and was impinging on the patellofemoral joint. Histologic and immunohistochemical studies revealed a myofibroblastic proliferation similar to nodular fasciitis. Until now, only 3 other cases have been reported in the English and Japanese language literature.

Arthroscopy↗

PubMed2002

Spinal extradural meningeal cyst: correct radiological and histopathological diagnosis.

OBJECT: Spinal extradural meningeal cysts are uncommon and rarely cause neural compression. The clinical, radiological, and histopathological characteristics of the lesions are discussed and previous reports reviewed. METHODS: The authors describe five cases of a spinal extradural meningeal cyst (three female and two male patients, with a mean age of 47 years (range 14-75 years). Four of the cysts were located at the thoracolumbar level, the fifth at the sacral level. Radiological and neuroimaging-based diagnosis was made using a combination of magnetic resonance imaging, myelography, and/or computerized tomography (CT) myelography. A connection between the spinal subarachnoid space and the cyst cavity was demonstrated on myelography and/or CT myelography in all cases, and dural defects were confirmed visually intraoperatively. In all cases histopathological examination confirmed that the cyst wall was formed by nonspecific fibrous connective tissue without a single-cell layer of inner arachnoid lining. CONCLUSIONS: A diagnosis of spinal extradural meningeal cyst is difficult to make based solely on histopathological examination. It is essential that the final characterization and diagnosis be based on intraoperative inspection combined with radiological and histopathological findings.

Adolescent↗

PubMed2002

Intradiscal pressure after repeat intradiscal injection of hypertonic saline: an experimental study.

Chemonucleolysis with chymopapain is an effective alternative to an operation for the treatment of some patients who have a lumbar intervertebral disc herniation. However, chymopapain is associated with rare but serious complications. Accordingly, alternative substances for chemonucleolysis have been sought. The main beneficial effect of chemonucleolysis derives from the decrease in the intradiscal pressure. We have previously reported that hypertonic saline injected into the intervertebral discs decreased the intradiscal pressure, but only temporarily. The present experimental study investigated changes in the intradiscal pressure after a repeat intradiscal injection of hypertonic saline. The lumbar intervertebral discs of 18 living rabbits were examined: 10% hypertonic saline was injected intradiscally just once in 12 rabbits, and the same dosage was injected again, 4 weeks later, in the same animals. The intradiscal pressure was measured at 1, 4, 8, and 12 weeks after the second injection. The remaining six rabbits were used as controls, without puncture and without injection. The intradiscal pressure of the group with repeat hypertonic saline injection at 4 weeks was significantly lower than that of the control group. The decreased pressure showed a tendency to increase at 8 weeks, and it had recovered at 12 weeks. The results of this study suggest that repeat hypertonic saline injections may be clinically useful.

Animals↗

PubMed2002

Charcot joint-like changes following ankle fracture in a patient with no underlying disease: report of a rare case.

Charcot joint is a disease that often occurs in patients with diabetes mellitus, tabes dorsalis, syringomyelia, chronic alcoholism, leprosy, trauma, or infection after fractures and dislocations. The treatment for Charcot joint has various complications, such as skin lesions, infections, and delayed union. We present our experience with a male patient who developed Charcot joint-like changes without diabetes mellitus or any other disease after an ankle fracture due to minor trauma.

Accidental Falls↗

PubMed2002

MRI quantification of muscle activity after volitional exercise and neuromuscular electrical stimulation.

OBJECTIVE: The efficacy, and even the depth, of muscle stimulation during surface electrode neuromuscular electrical stimulation (NMES) is a matter of debate. This study addresses these issues by assessing the utility of a magnetic resonance imaging (MRI) technique in localizing and quantitating changes in the nature of MRI signals in the quadriceps muscle after volitional exercise and NMES. DESIGN: Volitional isometric and NMES-evoked quadriceps muscle activity was evaluated in two controlled trials. In the first, isometric quadriceps strength was determined during NMES and maximal volitional isometric exercise in six healthy men. In the second, changes in the ratio of MRI T2 signal intensities before and after volitional isometric exercise and NMES were used to quantitate MRI signal changes associated with muscle activation in 12 additional healthy men. RESULTS: MRI clearly detected quadriceps muscle tissue activation after both volitional and stimulated contractions, even though the NMES knee extension torque was only 23.5% that of maximal volitional isometric exercise. In particular, the T2 intensity ratios increased 26.5% +/- 17.3% (mean +/- standard deviation) after volitional exercise and 12.9% +/- 12.8% after NMES. This pattern of volitional isometric exercise, producing larger T2 intensity ratio values than NMES, was present in both deep and superficial layers and throughout the quadriceps muscle. CONCLUSIONS: Although volitional muscle contractions were several times stronger than those induced by NMES in this study, our findings support the idea that MRI can provide a noninvasive way to quantitate and localize volitional and electrically stimulated muscle activation.

Adult↗

PubMed2002

Confocal laser microscopy of chondrocytes that received gene transfer using in vitro electroporation.

To develop a gene therapy for osteopathies, this study was conducted to establish a method of transferring the BMP gene, a bone formation factor, to cells and administering the cells with BMP expression to patients with osteopathies. Although virus vectors are frequently used for gene transfer, there has been reported a death case of gene therapy using the adenovirus vector. Therefore, various efforts have been made to prevent such complications. In the present study, we used electroporation by which gene transfer can be efficiently performed without inducing severe complications after electric perforation of the cell membrane. Human bone tissues were initially collected intraoperatively, and BMP-2 and Smad4 genes were cloned and integrated into GFP and DsRed plasmid vectors. Using in vitro electroporation, these plasmid vectors were transferred to the cultured chondrocytes (KTN-1) derived from human herniated intervertebral disk. Confocal laser microscopy revealed that the BMP gene was successfully transferred to the nucleus of chondrocytes in the presence of Smad. Since electroporation facilitated human gene transfer to the target cells, gene therapy using electroporation may facilitate individualized treatment for patients.

Base Sequence↗

PubMed2002

Combined fractures in the capitellum and the radial head associated with medial capsular avulsion.

We present a case with an unusual fracture. A 28-year-old man presented a painful and swollen left elbow after falling down. Radiographs revealed combined fractures in the capitellum and the radial head associated with a medial capsular avulsion. Two osteochondral fragments from the capitellum were found at the operation. One was the free fragment revealed on radiographic examination. Another was not revealed before the operation and was found piercing the fracture line of the radial head. These two fragments were removed. The radial head fracture was reduced and was fixed using two Herbert screws. It is very difficult to detect a fragment of the capitellum that impaled the radial head on a plain radiogram before operation. Also, a capsular injury and/or ligamentous injury is often overlooked. This fact should be kept in mind whenever a non-operatively treated radial head fracture fails to respond as expected.

Adult↗

PubMed2002

Effect of AGEs on human disc herniation: intervertebral disc hernia is also effected by AGEs.

Currently, extracellular matrix MMP has been discussed in relation to the extrusion and spontaneous regression of the herniated mass observed in lumbar disc herniation. However, the question remains as to whether degenerated protein is really the cause of this condition's pathogenesis. We confirmed immunologically by means of electron microscopy that extrusion is caused by the AGEs (advanced glycation end products)-induced cross-linking of collagen, and that spontaneous regression is due to AGE receptors on macrophages. Further, AGEs were found to be already exposed during histogenesis, suggesting a relation to apoptosis. In lumbar disc herniation and aging, glucose-derived AGEs cross-link proteins and cause vascular tissue damage.

Base Sequence↗

PubMed2001

Relationship of p21 (waf1/cip1) and differentiation in chondrosarcoma cells.

The histological grade of chondrosarcoma correlates well with their clinical behavior and with the patient's survival duration. We have previously demonstrated that p21 was expressed in the hypertrophic chondrocytes of the growth plate. To assess the relationship of p21 (waf1/cip1) to cell differentiation in chondrosarcoma, we examined the p21 expression in 14 cases of chondrosarcoma immunohistochemically and the induction of p21 by insulin-like growth factor-I (IGF-I) during cell differentiation in SW1353 chondrosarcoma cells. p21 immunoreactivity was seen in well-differentiated chondrosarcoma cells and was mutually exclusive with MIB1 reactivity in grade-1 chondrosarcoma. In vitro, the proteoglycan synthesis of SW1353 cells was increased by IGF-I in a dose-dependent manner. However, cell proliferation was not markedly stimulated. Overexpressions of p21 mRNA and p21 protein in SW1353 cells were induced by IGF-I 100 ng/ml. Our results suggested that the p21 expression was directly related to tumor differentiation and that the p21 expression was an important mediator for IGF-I in chondrosarcoma cells.

Antigens, Nuclear↗