Biomedical subjects

Ryohei Takeuchi

Publications and source records attributed to Ryohei Takeuchi.

6 recordsLinked to original sources

PubMed2006

Effects of vibration and hyaluronic acid on activation of three-dimensional cultured chondrocytes.

OBJECTIVE: To investigate the effects of vibration (Vib) and hyaluronic acid (HA) on 3-dimensional cultured cartilage. METHODS: Chondrocytes were obtained from metatarsophalangeal joints of freshly killed 6-month-old pigs. Twenty-four-well plates containing type I collagen sponge disks were used to culture samples. The frequency and the amplitude of the vibration of the well plate were 100 Hz and 0.5 nm, respectively. We produced 3-dimensional cartilage tissue using HA and vibration with collagen sponge as a carrier. Four different culture conditions were examined: a control HA-Vib- group, an HA-Vib+ group, an HA+Vib- group, and an HA+Vib+ group. Each group was cultured for 2 weeks. After culture days 3, 7, 10, and 14 (every 3.5 days), the levels of chondroitin 4-sulfate (C4S) and chondroitin 6-sulfate (C6S) isomers synthesized in each culture medium were measured. Histologic analysis, immunohistochemical analysis, and electron microscopic examination were performed. RESULTS: Mean C4S and C6S synthesis had increased rapidly after 7 days of culture and continued to increase thereafter. There were significant differences among the 4 groups (P < 0.01). Synthesis of both C4S and C6S was most abundant in the HA+Vib+ group and the lowest in the HA-Vib- group. After 1 and 2 weeks of culture, the chondrocytes had formed stratified structures on the collagen sponges in all groups, although the thickest structure was observed in the HA+Vib+ group and the thinnest in the HA-Vib- group. Under immunofluorescence, the HA+Vib+ group exhibited the strongest chromatic features. Under electron microscopy, the chondrocytes in the HA+Vib+ group exhibited many long and slender prominences on their surface, and extracellular substance could be observed associated with the cells. CONCLUSION: Our results indicate that the combination of vibration and HA activates the production of proteoglycan in 3-dimensional cultured chondrocytes and stimulates MAPK and beta-catenin. This suggests that some mechanoreceptors for vibration exist on the plasma membrane of chondrocytes and activate the intracellular signal transduction system.

Animals↗

PubMed2002

Slow-releasing potential of vancomycin-loaded porous hydroxyapatite blocks implanted into MRSA osteomyelitis.

Although antibiotic-loaded hydroxyapatite blocks have been used for the treatment of chronic osteomyelitis, their long-term potential for releasing antibiotic into human bones is not well known. Five patients with chronic osteomyelitis due to methicillin-resistant Staphylococcus aureus (MRSA) infection were effectively treated with local implantation of vancomycin-loaded hydroxyapatite blocks. Blocks were removed during the following reconstructive surgeries when the releasing capability of the blocks, and the bacteriocidal activity of the remaining vancomycin in these blocks could be evaluated. Vancomycin was rapidly released within 1 month after implantation, and by 3 months 90% of vancomycin had leaked from the blocks. At 18 months vancomycin still remained in a bacteriocidal form in the hydroxyapatite blocks, though the blocks had no releasing potential or the eluted vancomycin had been changed to a different form. Vancomycin-loaded porous hydroxyapatite blocks would be useful for the treatment of chronic osteomyelitis or implant-associated osteomyelitis due to MRSA.

Adult↗

PubMed2002

High tibial osteotomy with anterior advancement of distal fragment for medial and patellofemoral compartmental osteoarthritis of the knee.

High tibial osteotomy was performed in 73 knees of 50 patients with medial and patellofemoral compartmental osteoarthritis of the knee, which was combined with anterior advancement of the distal fragment. At the operation, parapatellar release of the retinaculum and subperiosteal elevation of contracted medial soft tissue were also adjoined. The average age of the patients at the time of surgery was 64 years. The follow-up period was an average of 58 months. On overall clinical results assessed with the Knee Society score, the average total knee score was improved from preoperative 50 points to postoperative 94, and the preoperative average functional score of 47 points increased to 92 postoperatively. At follow-up, pain from a grinding patella was not found in 68 of 73 knees and pain from grinding and deviating of the patella was relieved in more than 96% of all cases. The mean femorotibial angle was reduced from preoperative 185 degrees to postoperative 167 degrees. On skyline view, the width of the lateral facet joint space was widely opened postoperatively, particularly on the flexion angle of 90 degrees. This operative procedure successfully relieved patellofemoral symptoms of the patients with medial and patellofemoral compartmental osteoarthritis of the knee.

Aged↗

PubMed2002

Increase in range of knee motion to obtain floor sitting after high tibial osteotomy for osteoarthritis.

In order to obtain better range of motion in knees with osteoarthritis, medial and lateral parapatellar retinaculo-capsular release operations were performed at the time of high tibial osteotomy, with fixation using dual plating on medial compartmental knee osteoarthritis (29 knees) or spontaneous osteonecrosis of the medial femoral condyle (15 knees). At removal of the blade plate, 1 to 2 years after the initial osteotomy, the same release procedures were performed together with resection of adhesive soft tissue and resection of osteophytes, which were obstacles to full flexion. A grading system (Grade 0-3) was proposed to evaluate the duration (min) of formal floor sitting. After these procedures, the patients were able to sit on the floor with 155-165 degrees of flexion for more than 30 min (Grade 3) in 20 knees, for 10-29 min (Grade 2) in seven, for less than 10 min (Grade 1) in nine and were unable to sit on the floor (Grade 0) in eight knees. Maximum knee flexion and total range of motion were 142+/-8.4 degrees and 137+/-11 degrees before and 152+/-6.6 degrees and 151+/-7.4 degrees after surgery, respectively. The American Knee Society Knee Score and Function Score were 61+/-17 and 46+/-16 before, and 97+/-5 (P<0.0001) and 91+/-13 (P<0.0001) after surgery at the final follow-up, respectively. The femoro-tibial angle in standing with one leg was 183+/-6 degrees (3 degrees of anatomical varus angulation) before and 170+/-3 degrees (P<0.0001) (10 degrees of anatomical valgus angulation) after surgery.

Aged↗

PubMed2002

Minimally invasive fixation for unstable two-part proximal humeral fractures: surgical techniques and clinical results using j-nails.

OBJECTIVES: To evaluate the outcome of a minimally invasive treatment of unstable two-part proximal humeral fractures using a J-nail. DESIGN: Retrospective case series. PATIENTS: Forty-one unstable two-part proximal humeral fractures (thirty women and eleven men) with a mean age of sixty-five years (range 18 to 95 years) were studied. INTERVENTION: Closed reduction and internal fixation with J-nails. MAIN OUTCOME MEASURES: All fractures were classified using Neer's classification and were displaced and unstable. Forty of the two-part fractures were at the surgical neck and one at the anatomic neck. All patients had a closed reduction and intramedullary fixation using three J-nails. The mean follow-up period was twenty-nine months (range 2 to 4 years). Clinical assessment was performed by doctors who did not participate in the primary surgery and was graded according to Neer's scoring system. RESULTS: All patients experienced immediate pain relief. At the two-year follow-up, the mean angles of active forward elevation, abduction, and extension were 138 degrees (range 80 to 180 degrees), 132 degrees (range 80 to 170 degrees), and 65 degrees (range 40 to 85 degrees), respectively. According to Neer's criteria, the outcome was excellent in twenty-five patients, satisfactory in twelve, unsatisfactory in three, and a failure in one. The final Neer's score showed a significant negative correlation with age (p < 0.01). CONCLUSION: J-nail fixation has the advantage of being an almost closed method without the disadvantage of muscle transfixation associated with other methods. The procedure is simple and involves minimal invasion of the soft tissue. Shoulder and elbow function is not impeded because the nails are inserted just below the distal part of the deltoid muscle insertion. This surgical technique may be one of the more reliable and effective treatments for proximal humeral fractures.

Adolescent↗

PubMedDate not supplied

Double-bundle anatomic anterior cruciate ligament reconstruction using bone-hamstring-bone composite graft.

The bone-hamstring-bone (BHB) composite graft is a hybrid ligament reconstruction methodology that combines the advantages but eliminates the disadvantages of the bone-patellar tendon-bone (BPTB) and tendon of semitendinosus and gracilis muscle (STG) methods. We have developed an innovative modified BHB method involving anatomic anterior cruciate ligament (ACL) reconstruction. It takes into account the 2 bundles of the ACL: the anteromedial bundle and the posterolateral bundle. The composite graft was prepared by folding the gracilis and the semitendinosus tendons twice and flanking the ends by bone blocks obtained from the tibia. One tunnel of 11-mm diameter was made in the tibia and the femur, and the top of the graft was introduced into the femoral socket; the distal end of the graft was rotated 90 degrees in the counterclockwise direction for a right knee and 90 degrees in the clockwise direction for a left knee to apply a twist to the graft, giving rise to an anteromedial bundle and a posterolateral bundle. The bone blocks attached to the graft were fixed with 2 interference screws. Modified BHB technique allows free selection of the location of the bone plug, minimizes the intra-articular length of the graft, and maintains the double-bundle structure of the original ACL.

Anterior Cruciate Ligament↗