Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Hajime Owaki is active.

Publication


Featured researches published by Hajime Owaki.


Journal of Bone and Joint Surgery-british Volume | 1989

Repair of rabbit articular surfaces with allograft chondrocytes embedded in collagen gel

Shigeyuki Wakitani; Tomoatsu Kimura; Atsushi Hirooka; Takahiro Ochi; Minoru Yoneda; Natsuo Yasui; Hajime Owaki; Keiro Ono

In an attempt to repair articular cartilage, allograft articular chondrocytes embedded in collagen gel, were transplanted into full-thickness defects in rabbit articular cartilage. Twenty-four weeks after the transplantation, the defects were filled with hyaline cartilage, specifically synthesising Type II collagen. These chondrocytes were autoradiographically proven to have originated from the transplanted grafts. Assessed histologically the success rate was about 80%, a marked improvement over the results reported in previous studies on chondrocyte transplantation without collagen gel. By contrast, the defects without chondrocyte transplantation healed with fibrocartilage. Immunological enhancement induced by transplanted allogenic chondrocytes or collagen was not significant at eight weeks after treatment, so far as shown by both direct and indirect blastformation reactions. Thus, allogenic transplantation of isolated chondrocytes embedded in collagen gel appears to be one of the most promising methods for the restoration of articular cartilage.


Cell | 1986

Molecular structure of human lymphocyte receptor for immunoglobulin E

Hitoshi Kikutani; Seiji Inui; Ryoichi Sato; Edward L. Dr. Barsumian; Hajime Owaki; Katsuhiko Yamasaki; Tsuneyasu Kaisho; Naoto Uchibayashi; Richard R. Hardy; Toshio Hirano; Susumu Tsunasawa; Fumio Sakiyama; Masaki Suemura; Tadamitsu Kishimoto

We have isolated and sequenced a cDNA clone encoding the human lymphocyte receptor for IgE (Fc epsilon R). The deduced protein sequence reveals that Fc epsilon R consists of 321 amino acids, without any signal sequence, and is oriented with its N-terminus on the cytoplasmic side and its C-terminus on the outside of the cell. This molecule shows striking sequence homology with chicken asialoglycoprotein receptor (hepatic lectin), suggesting a possible role for Fc epsilon R in endocytosis. Fc epsilon R mRNA is expressed in B cells, B cell lines, and macrophage cell lines. It is not expressed in T cells or T cell lines, with the exception of an HTLV-transformed T cell line. mRNAs expressed in a macrophage line and in the latter T cell line differ in size from mRNA expressed in B cells. Human BSF-1 (or IL-4) induces the expression of Fc epsilon R mRNA in B cells, but not in T cells.


Spine | 1998

Cervical lesions related to the systemic progression in rheumatoid arthritis

Keiju Fujiwara; Masahiro Fujimoto; Hajime Owaki; Jyoji Kono; Takanobu Nakase; Kazuo Yonenobu; Takahiro Ochi

Study Design. Cross‐sectional study of cervical involvement in rheumatoid arthritis. Objectives. To clarify the correlation between the deterioration of cervical lesions and the systemic progression of rheumatoid arthritis. Summary of Background Data. The natural course of cervical lesions varies. To date, no systemic parameter has been clarified to predict the progression. Methods. One hundred seventy‐three patients with rheumatoid arthritis participated in this study. The authors studied the progression of cervical lesions and investigated the relation between the types of cervical subluxation at the end of study and the following four variables: the serum level of C‐reactive protein, the number of joints with erosion, carpal height ratio, and disease subset (least erosive subset, more erosive subset, and mutilating disease subset). Results. Of the 173 patients, 55 already had cervical subluxation before entering the study. During the follow‐up period, 44 patients deteriorated radiographically, and 77 (45%) had cervical involvement, including involvement of upper cervical lesions in 65 patients, upper lesions combined with subaxial subluxation in 10, and subaxial subluxation alone in 2. The upper cervical subluxation progressed in the order of anterior atlantoaxial subluxation, atlantoaxial subluxation combined with vertical subluxation, and vertical subluxation alone. Deterioration of upper cervical lesion and occurrence of subaxial subluxation were closely correlated with an elevation of serum C‐reactive protein level, an increase in the number of joints with erosion, and a decrease in the carpal height ratio. The incidence of cervical involvement and the extent of deterioration were different among the disease subsets. Conclusions. The serum level of C‐reactive protein, the number of joints with erosion, and the carpal height ratio correlated closely with the extent of the cervical subluxation. The average C‐reactive protein values during the follow‐up period correlated with progression of the cervical lesions. The classification of rheumatoid disease subset was useful for predicting the terminal feature of the cervical lesions.


Journal of Spinal Disorders | 2000

A long-term follow-up study of cervical lesions in rheumatoid arthritis.

Keiju Fujiwara; Hajime Owaki; Masahiro Fujimoto; Kazuo Yonenobu; Takahiro Ochi

To determine the natural history of cervical lesions in rheumatoid arthritis, 161 patients who had been followed for a minimum of 5 years were enrolled in this study. The average follow-up period was 10.2 years (range, 5 to 20 years). The severity of the rheumatoid arthritis was classified into three types based on the multiplicity of peripheral joint rheumatoid involvement: a least erosive subset, a more erosive subset, and a mutilating disease subset. Ninety-two patients (57%) had upper cervical involvement, which progressed in the order of anterior atlantoaxial subluxation, anterior atlantoaxial subluxation combined with vertical subluxation, and vertical subluxation alone. Subaxial subluxation was found in 18 patients (11%). In 17 of these 18 patients, upper cervical lesions were also noted. The incidence of cervical involvement in each disease subset was 39% in the least erosive group, 83% in the more erosive group, and 100% in the mutilating disease group. Fifty percent of the patients with cervical involvement had neck pain, and the remaining patients were asymptomatic. Neural involvement occurred in 10 patients. In 7 of these 10 patients, vertical subluxation of the atlas was responsible for the neural deficit. Six patients required surgical intervention because of progressive myelopathy.


Scandinavian Journal of Rheumatology | 1991

Facs Analysis of Myeloid Differentiation Stages in Epiphyseal Bone Marrow, Adjacent to Joints Affected with Rheumatoid Arthritis

Hajime Owaki; K. Yukawa; Takahiro Ochi; Yasunori Shimaoka; K. Ono

To analyze the differentiation stages of myeloids statistically, we adopted a two-color FACS system and used appropriate monoclonal antibodies belonging to CD15, CD16 and CD11b. By using HL60 treated with DMSO or human bone marrow MNCs from patients with rheumatoid arthritis, it was proved that with this system, myeloids could be clearly separated according to differentiation stages. Furthermore, the number of myeloids at certain stages of differentiation in the epiphyseal bone marrow of patients with RA or OA was measured. Nine of 15 samples from RA patients showed immature and relatively mature myeloids, while none of the 8 OA samples did. When the proportions of myeloids in epiphyseal bone marrow MNCs were compared with the clinical features, disease subsets in RA and the degree of synovitis, seemed to be important factors for abnormal myelopoiesis.


Journal of Bone and Joint Surgery-british Volume | 2016

Changes in axial alignment of the ipsilateral hip and knee after total hip arthroplasty

Keisuke Akiyama; K. Nakata; M. Kitada; M. Yamamura; T. Ohori; Hajime Owaki; Takeshi Fuji

AIMS We investigated changes in the axial alignment of the ipsilateral hip and knee after total hip arthroplasty (THA). PATIENTS AND METHODS We reviewed 152 patients undergoing primary THA (163 hips; 22 hips in men, 141 hips in women) without a pre-operative flexion contracture. The mean age was 64 years (30 to 88). The diagnosis was osteoarthritis (OA) in 151 hips (primary in 18 hips, and secondary to dysplasia in 133) and non-OA in 12 hips. A posterolateral approach with repair of the external rotators was used in 134 hips and an anterior approach in 29 hips. We measured changes in leg length and offset on radiographs, and femoral anteversion, internal rotation of the hip and lateral patellar tilt on CT scans, pre- and post-operatively. RESULTS The mean internal rotation increased by 11° (-15° to 46°) and was associated with underlying disease (OA), pre-operative range of internal rotation, gender, surgical approach, leg lengthening, and change of femoral anteversion (adjusted R(2) : 0.253, p < 0.001). The mean lateral patellar tilt increased by 4° (-5° to 14°) and was associated with age, leg lengthening, and increment of hip internal rotation (adjusted R(2): 0.193, p < 0.001). CONCLUSION Both internal rotation of the hip at rest and lateral patellar tilt are increased after THA. Changes in rotation after THA may affect gait, daily activities, the rate of dislocation of the hip, and ipsilateral knee pain. TAKE HOME MESSAGE Internal rotation of the hip at rest and lateral patellar tilt increase after THA.


Journal of orthopaedic surgery | 2014

Disease activity, knee function, and walking ability in patients with rheumatoid arthritis 10 years after primary total knee arthroplasty

Masataka Nishikawa; Hajime Owaki; Koichiro Takahi; Takeshi Fuji

Purpose. To evaluate disease activity, knee function, and walking ability of patients with rheumatoid arthritis (RA) over 10 years after total knee arthroplasty (TKA). Methods. Four men and 26 women (mean age, 59.9 years) underwent 42 TKAs for RA with a mean duration of 151.3 months and were followed up for a mean of 142.3 months. Preoperatively, disease activity was assessed by C-reactive protein (CRP) level only, and the range of knee motion was recorded. At the final follow-up, tender joint count, swollen joint count, visual analogue scale of RA symptoms, and the Modified Health Assessment Questionnaire (MHAQ) score were assessed. Disease activity was evaluated using CRP, matrix metalloproteinase-3, and Disease Activity Score. Range of motion and Knee Society knee and function scores were also assessed. Results. The use of methotrexate increased from 4 patients preoperatively to 20 patients at the final follow-up (p<0.001), and the mean dose increased from 3.9 to 6.3 mg/week (p<0.001). Among the 30 patients, the mean CRP level decreased from 2.63 mg/dl preoperatively to 0.61 mg/dl at the final follow-up (p<0.001). Disease activity was controlled. At the final follow-up, disease activity was in remission in 10 patients, low in 11, and moderate in 9. The mean Knee Society knee score was excellent (91.0), but the mean function score was poor (57.0) and diverse. Severe walking disability (function score, <40) was noted in 8 patients (11 TKAs). Knee and function scores did not correlate. Conclusion. Walking ability in patients with RA after TKA was generally poor. Poor function was associated with a history of spinal or lower extremity fracture surgery and the MHAQ score.


Modern Rheumatology | 2017

Outcomes of modified metatarsal shortening offset osteotomy for forefoot deformity in patients with rheumatoid arthritis: Short to mid-term follow-up

Makoto Hirao; Kosuke Ebina; Hideki Tsuboi; Akihide Nampei; Junichi Kushioka; Takaaki Noguchi; Shigeyoshi Tsuji; Hajime Owaki; Jun Hashimoto; Hideki Yoshikawa

Abstract Objectives: Advances in drug therapy for rheumatoid arthritis (RA) have been encouraging us to preserve the metatarsopharangeal (MTP) joint in correction of forefoot deformities, and original metatarsal shortening offset osteotomy was recommended as one of the conventional surgical options for forefoot deformities in RA cases. The objective of this study was to evaluate short- to mid-term outcomes of modified metatarsal shortening offset osteotomy. Methods: A retrospective observational study was completed for 80 RA cases (mean follow-up period: 3.2 years) who underwent modified metatarsal shortening offset osteotomy. Both lesser toe scales and RA foot ankle scales were administered using the Japanese Society for Surgery of the Foot (JSSF) standard rating system, and a postoperative self-administered foot evaluation questionnaire (SAFE-Q) at final follow-up was also checked to evaluate clinical outcomes. Results: This procedure significantly improved clinical scores of both the JSSF [lesser toes and RA foot and ankle] scales. Of 80 feet, 24 (30%) showed recurrence of MTP joint subluxation/dislocation. Furthermore, the feet in the recurrence group showed significant varus hindfoot. On the other hand, valgus foot in the recurrence group more frequently included midfoot bony ankyloses. All of the affected feet showed the limitation of MTP joints (<70°) after surgery. Conclusions: Modified metatarsal shortening offset osteotomy was recommended for RA forefoot disorders as one of the joint preservation surgeries in short- to mid-term follow-up. However, some modifications to avoid limitation of ROM in the MTP joint are required. It must be borne in mind that varus hindfoot and/or bony ankyloses in the mid-hindfoot can cause recurrence of dorsal dislocation/subluxation of the lesser toe MTP joint.


Journal of clinical orthopaedics and trauma | 2015

Acquired permanent dislocation of the patella in a patient with rheumatoid genu valgum

Masataka Nishikawa; Hajime Owaki; Shoichi Kaneshiro; Takeshi Fuji; Kenrin Shi

A case of acquired permanent dislocation of the patella associated with severe genu valgum in a patient with rheumatoid arthritis (RA) is herein reported. The pain and genu valgum progressed because of poor RA control. The patient had no history of major trauma of the knee before or after the onset of RA. The most reasonable hypothesis to explain this patients pathology is that occult patellar dislocation developed after a minor trauma and progressed to permanent dislocation; poor RA control then worsened both the patellar dislocation and genu valgum. Total knee arthroplasty (TKA) with patella reduction was successfully performed with release of the lateral retinaculum and extension of the extensor mechanism by partial snipping of the rectus femoris tendon. Two years after the operation, the patient exhibited improvement in her Knee Society Knee and Function Scores from preoperative scores of 18 and 20 to postoperative scores of 94 and 80, respectively. Acquired permanent dislocation of the patella associated with severe genu valgum in patients with RA is rare. Excellent results were obtained with TKA, and the proximal realignment method was a useful procedure for patella reduction.


Modern Rheumatology | 2018

The add-on effectiveness and safety of iguratimod in patients with rheumatoid arthritis who showed an inadequate response to tocilizumab

Kosuke Ebina; Akira Miyama; Hideki Tsuboi; Shoichi Kaneshiro; Masataka Nishikawa; Hajime Owaki; Shigeyoshi Tsuji; Makoto Hirao; Yuki Etani; Atsushi Goshima; Jun Hashimoto; Hideki Yoshikawa

Abstract Objectives: To evaluate the effectiveness of add-on iguratimod (IGU) in patients with rheumatoid arthritis (RA) who showed an inadequate response to tocilizumab (TCZ), especially patients who were intolerant of an effective dose of methotrexate (MTX). Methods: Thirty-one patients with RA (22 women, age 62.4 years, disease duration 13.8 years, prior TCZ duration 35.7 months, 25 intravenous [8 mg/kg/4 weeks] and 6 subcutaneous [162 mg/2 weeks] TCZ treatments, concomitant MTX 8.5 mg/week [35.5%], and prednisolone (PSL) 4.3 mg/day [25.8%]) who showed an inadequate response to TCZ (disease activity score assessing 28 joints with C-reactive protein [DAS28-CRP] 2.9, clinical disease activity index [CDAI] 15.0, 28 secondary inadequate responders) were treated with additional IGU (final dose 41.7 mg/day) and enrolled in this 24-week, multicenter, retrospective study. Results: Twenty-nine patients (93.5%) continued the treatment for 24 weeks (one dropped out for pneumonia and one for digestive symptoms). The TCZ and the concomitant dose and rate of conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) (MTX, salazosulfapyridine [SASP], and tacrolimus [TAC]) were not significantly changed during this period. Outcome measures improved significantly, as follows: DAS28-CRP from 2.9 to 1.7 (p < .001); CDAI from 15.0 to 6.0 (p < .001); modified Health Assessment Questionnaire (mHAQ) from 0.8 to 0.6 (p < .05); and rheumatoid factor (RF) from 382.1 to 240.3 IU/mL (p < .001). Using the EULAR criteria, 64.5% achieved a moderate response, and 51.6% achieved ACR 20 at 24 weeks. Conclusion: Adding IGU to inadequate responders to TCZ may be a promising and safe complementary treatment option.

Collaboration


Dive into the Hajime Owaki's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge