Biomedical subjects

Yuji Yasunaga

Publications and source records attributed to Yuji Yasunaga.

43 records · Page 3Linked to original sources

PubMedDate not supplied

Changes of the mineralization pattern in the subchondral bone plate of the glenoid cavity in the shoulder joints of the throwing athletes.

The distribution of mineralization in the subchondral bone plate (DMSB) is used as a parameter for individual stress distribution of shoulder joints. We have analyzed 28 shoulder joints of throwing athletes by DMSB of the glenoid with computed tomography osteoabsorptiometry and described their mineralization patterns. The throwing motion imposes a heavy rotational load on the shoulder joint, and this, in turn, may lead to excessive translation of the humeral head on the glenoid. This could explain why the two most frequent density maxima were localized to the anterior and posterior portions of the glenoid. Our finding of a frequent bicentric density distribution of the shoulder joints of throwing athletes should be useful in any future analysis of the relationship between the DMSB and the bone morphology of the glenoid.

Adolescent↗

PubMedDate not supplied

Allogeneic bone marrow-derived mesenchymal stromal cells promote the regeneration of injured skeletal muscle without differentiation into myofibers.

Half-stratum laceration was performed on the tibialis anterior muscle of Sprague-Dawley (SD) rats as a skeletal muscle injury model. Bone marrow-derived mesenchymal stromal cells (BMMSCs), which were derived from enhanced green fluorescent protein (GFP) transgenic SD rats, were transplanted into the injured site. Tensile strength produced by nerve stimulation was measured for functional evaluation before sacrifice. Specimens of the tibialis anterior muscles were stained with hematoxylin and eosin, and immunohistochemically stained for histological evaluation. Our results showed that transplanted BMMSCs promoted maturation of myofibers histologically and made the injured muscle acquire almost normal muscle power functionally by 1 month after transplantation. However, the results of immunohistochemical staining could not prove that transplanted BMMSCs differentiated into or fused to skeletal myofibers, although it showed that transplanted BMMSCs seemed to differentiate into muscle precursor cells. Therefore, our results indicated that BMMSCs contributed to the regeneration of skeletal muscle by mechanisms other than fusion to myofibers after differentiation.

Animals↗

PubMedDate not supplied

Arteriovenous malformation of the ring finger. Pre- and postoperative evaluation using three-dimensional computed tomography angiography.

We experienced a case of arteriovenous malformation of the ring finger. The lesion was examined by three-dimensional computed tomography angiography with volume rendering and maximum intensity projection techniques pre- and postoperatively. The images demonstrated the location and extent of the lesion and were quite useful for surgical planning and the evaluation of operative results. Three-dimensional computed tomography angiography may be a valuable diagnostic tool even in the evaluation of peripheral vascular lesions.

Adult↗

PubMedDate not supplied

Relationship between osteochondritis dissecans of the lateral femoral condyle and lateral menisci types.

The purpose of this study was to examine the relationship between osteochondritis dissecans (OCD) of the lateral femoral condyle and lateral menisci. From 1993 to 2002, 38 knees (28 patients) were diagnosed with OCD of the lateral femoral condyle. OCD locations were graded by the Cahill and Berg classification. The types of lateral menisci were classified by Watanabe's classification. The relationship between OCD of the lateral femoral condyle and lateral menisci was examined. On the anterior-posterior view, 25 OCDs were located in zone 4 and 13 in zone 5. The types of lateral menisci were complete discoid in 19 knees, incomplete discoid in 15, and normal in 4. Ten of the 19 complete discoid menisci were damaged. Complete discoid menisci without tears were found in OCDs located in zone 4; incomplete discoid menisci were found in OCDs located in zone 5. The authors found a relationship between the type of OCD and the state of the lateral meniscus.

Adolescent↗

PubMedDate not supplied

Three-dimensional computed tomography imaging: its applicability in the evaluation of extensor tendons in the hand and wrist.

OBJECTIVE: The purpose of this study was to determine whether 3-dimensional (3D) computed tomography (CT) imaging with volume rendering can accurately evaluate extensor tendons in the hand and wrist. METHODS: Three-dimensional CT imaging was used to evaluate 14 cases. The location where the rupture was suspected was the wrist level in all cases. The accuracy of the image diagnosis was confirmed during surgery in 13 cases. RESULTS: Three-dimensional CT could identify all extensor tendons proximal to the metacarpophalangeal joint. In the cases with rupture, the location of the distal stump could be identified, whereas that of the proximal stump was uncertain. The tendon stump location confirmed during surgery correlated well with the images. CONCLUSIONS: This study revealed the usefulness of 3D CT imaging in defining extensor tendons proximal to the metacarpophalangeal joint. This method increased the accuracy and ease of diagnosis and was always useful in surgical planning and patient education.

Adult↗

PubMedDate not supplied

Three-dimensional computed tomography imaging evidence of regeneration of the semitendinosus tendon harvested for anterior cruciate ligament reconstruction: a comparison with hamstring muscle strength.

OBJECTIVE: The purpose of this study was to evaluate the regeneration of semitendinosus tendons harvested for anterior cruciate ligament (ACL) reconstruction using 3-dimensional (3D) computed tomography (CT) imaging and to compare the degree of regeneration with hamstring strength. METHODS: Twenty-nine patients who underwent ACL reconstruction using ipsilateral autogenous semitendinosus tendons were examined before surgery and 6 and 12 months after surgery by 3D CT imaging. The types of regenerated tendons and the proximal shift of the muscle-tendon junction were evaluated. RESULTS: The types of regenerated semitendinosus tendons varied from case to case. There was a positive correlation between the peak torque ratio of the hamstring muscle strength and the proximal shift of the muscle-tendon junction 6 months after surgery. The proximal shift did not affect the peak torque ratio 12 months after surgery, however. CONCLUSIONS: A proximal shift of the muscle-tendon junction may help to explain the individual differences in early postoperative hamstring muscle strength recovery.

Adolescent↗

PubMedDate not supplied

Postradiation malignant fibrous histiocytoma and osteosarcoma of a patient with high telomerase activities.

BACKGROUND: An extremely rare case of postradiation malignant fibrous histiocytoma (MFH) and osteosarcoma (OS) secondary to radiation therapy for leukemia-related osteolytic lesions is presented. In addition, the telomere biology of these tumors was investigated. CASE REPORT: A 14-year-old boy was diagnosed with acute lymphocytic leukemia. The right tibia was irradiated at a total dose of 60 Gy, and the left tibia was irradiated at a total dose of 40 Gy. The left tibia developed MFH and the right tibia developed OS. RESULTS: Telomere reduction (MFH 70.2, OS 70.0%) and high telomerase activities (MFH 12.1, OS 17.7 TPG) were observed. These results reflect an aggressive feature of postradiation sarcomas. CONCLUSION: Prognosis for patients diagnosed with postradiation sarcoma is poor due to its aggressiveness. However, even if sarcoma occurs after irradiation in more than two fields in a single patient, improvements in prognosis are anticipated with appropriate chemotherapies and wide resection.

Adolescent↗