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Biomedical subjects

Kyoji Okada

Publications and source records attributed to Kyoji Okada.

44 records · Page 3Linked to original sources
PubMed2002

Enhanced antitumor effect of ultrasound in the presence of piroxicam in a mouse air pouch model.

The antitumor effects of piroxicam, a non-steroidal anti-inflammatory drug, on sarcoma 180 cells under ultrasonic irradiation were examined in a mouse air pouch model. When piroxicam was added to sarcoma 180 suspension under ultrasound irradiation (2 MHz, 10 W, 120 s), the mortality rate of tumor cells immediately after the irradiation and the survival rate of mice were significantly higher than those when ultrasound alone was applied, and these effects of piroxicam were dose-dependent. When D-mannitol was used with piroxicam, the mortality rate of the tumors cells after the irradiation was comparable with that when piroxicam alone was applied, but when L-histidine was used concurrently, the antitumor effect was significantly lower than that when piroxicam alone was applied. Histological examinations one week after the ultrasound irradiation in the presence of piroxicam showed sparse tumor tissue in the air pouch and normal appearance of the air pouch and surrounding tissue. The findings suggest that piroxicam enhances the anti-tumor effects of ultrasound in vivo by increasing the production of singlet oxygen without damage to tissue surrounding the tumor.

Animals↗
PubMedDate not supplied

Quantitative assessment of thinning of the subscapularis tendon in recurrent anterior dislocation of the shoulder by use of magnetic resonance imaging.

It is known that thinning and lengthening of the subscapularis tendon occur in shoulders with recurrent anterior dislocation. However, no studies have been performed to quantify the morphologic changes of the subscapularis tendon under such conditions. We retrospectively measured the thickness and cross-sectional area of the subscapularis tendon by use of magnetic resonance imaging in 22 shoulders in 11 patients with unilateral recurrent anterior dislocation of the shoulder. The contralateral shoulder in each patient served as a control. The thickness and cross-sectional area of the subscapularis on the affected side were smaller than those on the normal side (6.5 +/- 1.7 mm vs 8.0 +/- 1.9 mm, P = .001, and 388.6 +/- 120.0 mm 2 vs 547.9 +/- 128.5 mm 2 , P = .0001, respectively). We conclude that the subscapularis tendon undergoes an 18.7% decrease in thickness and a 29.1% decrease in cross-sectional area in shoulders with recurrent anterior dislocation.

Adolescent↗
PubMedDate not supplied

Apoptosis in the supraspinatus tendon with stage II subacromial impingement.

The purpose of this study was to investigate the histopathology, including apoptosis, in the supraspinatus tendon with stage II subacromial impingement. Samples from the critical zone of the supraspinatus tendon were obtained from 5 patients with subacromial impingement syndrome and 10 autopsy cases without shoulder diseases as controls. Three-micrometer-thick sections were cut and stained with hematoxylin-eosin (H-E) for routine histologic examination. Apoptosis was detected by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) method and single-stranded deoxyribonucleic acid (ssDNA) assay in which the frequency of the apoptotic cells was expressed by the apoptotic index. Control supraspinatus tendons showed normal morphology, whereas supraspinatus tendons from shoulders with impingement showed significant mucoid degeneration. Correspondingly, few apoptotic cells were observed in control tendons, whereas a large number of apoptotic cells were observed in the degenerative area of tendons from impingement shoulders. The apoptotic indices were significantly higher in the impingement shoulders (ssDNA, 18.84% +/- 1.75%; TUNEL, 24.92% +/- 2.79%) than in the control shoulders (ssDNA, 5.22% +/- 1.30%; TUNEL, 7.01% +/- 1.05%) (P = .04 for ssDNA and P = .017 for TUNEL). Mechanical impingement seems to cause tendon degeneration and apoptosis of the tendon cells in the supraspinatus tendon in stage II impingement.

Apoptosis↗
PubMedDate not supplied

Does reaching the back reflect the actual internal rotation of the shoulder?

To clarify the relationship between the vertebral level reached by the thumb and the internal rotation angle of the humerus, 7 shoulders in healthy volunteers were examined by use of an electromagnetic tracking device. Measurements were repeated in the hanging-arm position with the thumb pointing anteriorly and at the buttock, sacrum, and each vertebral level up to T6. From the hanging-arm position to the buttock, 54.3% of internal rotation occurred (mean, 39.8 degrees ), and from the buttock to the sacrum, 11.7% occurred (mean, 8.6 degrees ). In total, 66% of internal rotation occurred from the hanging-arm position to the sacrum. Above the sacrum, the contribution of elbow flexion to the level of the vertebral spine became much greater, and internal rotation of the shoulder did not change significantly above the T12 level. We recommend that the level of the thumb below the buttock be subdivided for more accurate assessment of internal rotation.

Adult↗
PubMedDate not supplied

Expression of growth factors in the early phase of supraspinatus tendon healing in rabbits.

Growth factors are known to appear during wound healing. We hypothesized that growth factors would also appear during the healing process of a rotator cuff tear. We determined the expression of various growth factors during healing of acute rotator cuff tears in the rabbit. We made a full-thickness defect in the supraspinatus tendon of 27 Japanese white rabbits. The shoulders were harvested on days 1, 3, 5, 7, 9, 11, 14, 21, and 28 postoperatively (n = 3 at each time point). We assessed the expression of basic fibroblast growth factor, insulin-like growth factor 1, platelet-derived growth factor, and transforming growth factor beta. Basic fibroblast growth factor appeared with its peak on days 7 and 9, insulin-like growth factor 1 appeared with its peak on day 5, platelet-derived growth factor appeared with a mild expression between days 7 and 14, and transforming growth factor beta appeared with constant mild expression throughout the observation period. It is likely that each of these growth factors plays a role in the early phase of healing of the supraspinatus tendon in rabbits.

Animals↗
PubMedDate not supplied

Ultrastructure of sarcoma 180 cells after ultrasound irradiation in the presence of sparfloxacin.

BACKGROUND: Sonodynamic synergistic antitumor effects have been well described to date, but detailed ultrastructural studies in this field are still lacking. MATERIALS AND METHODS: A suspension of sarcoma 180 cells was exposed to ultrasound (US) in the presence of sparfloxacin (SPFX), one of the new quinolone antibiotics, at 2 W (0.64 W/cm2) for 30 seconds. The antitumor effect was evaluated by the survival rate of cells and cell morphology by scanning and transmission electron microscopy. RESULTS: After US irradiation, the survival rate of tumor cells in the SPFX-added group was 30.9%, significantly lower than 78.7% in the control group (p = 0.0002). Most cells in the control group were spherical, but in the SPFX-added group the cells were aspherical. Cell membranes were often ruptured and numerous pores of various sizes were observed. Some cells were totally disintegrated. CONCLUSION: The most characteristic changes of the synergistic antitumor activities of US and SPFX were on the cell membrane.

Animals↗
PubMedDate not supplied

Doxorubicin-loaded calcium phosphate cement in the management of bone and soft tissue tumors.

Several materials have been used as drug delivery systems to maintain a high concentration of anticancer drugs at localized sites. The feasibility of using doxorubicin-loaded calcium phosphate cement (CPC) as a new material, which can release the drug as well as fill a postoperative bony defect, was investigated. The mechanical strength of cylinders of doxorubicin-loaded CPC was not lower than that of CPC alone. Culture medium incubated with doxorubicin-loaded CPC from 1 to 7 days suppressed the proliferation of RMT-1 E4 rat breast cancer cells. In rabbits with doxorubicin-loaded CPC in their femurs, histological examinations showed diffuse edematous changes in the medullary space, but neither fracture nor skin necrosis occurred. Doxorubicin-loaded CPC markedly inhibited the proliferation of sarcoma 180 cells in the mouse air-pouch model. These results indicate that doxorubicin-loaded CPC may be useful in the local treatment of malignant bone and soft tissue tumors.

Animals↗