Shogo Masumi

Inhibition of tubular morphogenesis in human microvascular endothelial cells by co-culture with chondrocytes and involvement of transforming growth factor β: a model for avascularity in human cartilage

Tube formation in collagen gel was induced in human omental microvascular endothelial (HOME) cells in the presence of epidermal growth factor (EGF) or transforming growth factor-alpha (TGF-alpha). TGF-alpha enhanced the expression of the tissue type plasminogen activator (t-PA) gene, whereas TGF-beta increased the expression of the PA inhibitor-1 (PAI-1) gene and inhibited that of the t-PA gene. TGF-beta inhibited the tube formation of HOME cells in type I collagen gel that was enhanced in response to TGF-alpha. We have recently established an angiogenesis model in vitro in which vascular endothelial cells on type I collagen gel in an inner chamber are co-cultured with other types of cells in an outer chamber. Here we examined whether the EGF/TGF-alpha-induced tube formation in HOME cells was modulated by human chondrocytes co-culture in the outer chamber. TGF-alpha-dependent tube formation of HOME cells was inhibited when human chondrocytes were co-cultured in the outer chamber. This chondrocyte-induced inhibition of tube formation was partly abrogated by co-administration of anti-TGF-beta antibody. These findings suggest that TGF-beta is partly involved in the human chondrocyte-dependent inhibition of tube formation by human microvascular endothelial cells. This is the first model system demonstrating that avascularity of human chondrocytes is partly due to TGF-beta family produced from them.

Bipolar hip arthroplasty without acetabular bone—grafting for dysplastic osteoarthritis: Results after 6–9 years

Abstract The authors report the clinical and radiographic results of 36 bipolar hip arthroplasties after performing excavation of the steep and shallow acetabulum without acetabular bone—grafting for dysplastic osteoarthritis. The procedures were carried out between 1981 and 1985. Survivorship analysis showed that 84.6 of the bipolar hip arthroplasties were retained for 8 years. Twenty-nine patients, which were followed for 6–9 years after surgery, were reviewed. Severity of acetabular dysplasia was classified according to the method of Crowe. Class 1 included 17 hips and class 2 included 12 hips. The average preoperative clinical score was 49 points. The average postoperative clinical hip score improved to 87 points after 6 years. Twenty-seven of the 29 hips assessed were classified as either excellent or good by Charnleys function score. Stress fracture, due to excessive acetabular excavation at the time of surgery, and femoral component loosening were major symptomatic complications. The cessation of radiographic evidence of migration of the bipolar socket was recognized in 25 of 29 procedures at 6 years after surgery (86.2%). Cineradiographic study demonstrated that the abduction motion under standing position for 20 of 24 hip joints functioned dominantly at the inner-bearing and metallic—stem interface.

Joint Motion of Bipolar Femoral Prostheses

From 1982 to 1992, 251 bipolar hip arthroplasties were performed on 213 patients. Among them, 117 bipolar femoral prostheses were randomly selected to examine the behavior of abduction motion under weight-bearing loads. Roentgenographic motion study was performed at an average of 46.5 months after surgery (range, 2-110 months). One hundred one prostheses used in dysplastic osteoarthritic, rheumatoid, and revised failed total hip arthroplasty patients moved 18.2% at the outer bearing and 81.8% at the inner bearing, while 16 prostheses used in femoral neck fracture and osteonecrosis of the femoral head patients moved 49.7% at the inner bearing and 50.3% at the outer bearing. There was a statistical difference in the motion pattern between the two groups. The abduction motion behavior of the bipolar femoral prostheses was not affected by the length of the follow-up period, the diameter of the outer heads, or the position of the prostheses on immediate postoperative roentgenograms.

Giant Vascular Leiomyoma in the Hand

Vascular leiomyoma or angioleiomyoma is a benign solitary tumour that arises from the mediae layer of the vein walls. It is usually located in the wall of the uterus. We describe a 73-year-old man who presented with a slowly growing mass in the thenar region of his right hand which, on histological examination, was shown to be a giant vascular leiomyoma. This is extremely rare and we could find only about 100 such cases reported in English.

Immunosuppressive effect of tacrolimus (FK-506): Bone xenografts in rabbits

We examined the immunomodulatory effect of the macrolide antibiotic FK-506 (tacrolimus) in bone xenograft transplantation. Full-thickness pieces of iliac bone from mongrel dogs were transplanted into the iliac bone of Japanese white rabbits. FK-506 at a dose of 1.6 mg/kg/day was injected into the rabbits for 10 days after transplantation. In the animals treated with FK-506, inflammatory cell infiltration was remarkably reduced and revascularization accompanied by new bone formation occurred in the grafts. At 4 months after the transplantation, the formation of new bone and of mature new bone marrow were observed. In a control group, inflammatory cell infiltration was marked around the graft from 2 weeks after the transplantation. Revascularization from the recipient site to the graft in the control group was poor and only a small amount of new bone had formed at 4 months. Our findings suggest that short-term administration of FK-506 has a beneficial effect on experimental xenograft bone transplantation.

Bipolar hip arthroplasty in rheumatoid arthritis.

Bipolar hip arthroplasty with bone grafting was performed on 25 joints with rheumatoid arthritis from 1981 to 1985. The results and roentgenographical progress of the grafted bone were followed for a minimum of two years, the longest follow-up examination occurring six years after the operation. The clinical score was assessed by the hip rating score of the Japanese Orthopaedic Association, which assigns a maximum of 100 points. The preoperative clinical score ranged from 22 to 59 points (mean, 42.6). The postoperative score improved to a range of 65-92 points (mean, 72.8). Of 24 hips examined, 21 (87.5%) were painless. As measured serially from the roentgenograms made immediately after the operation, the overall distance of central migration in 24 hips was 0-8.5 mm (average, 2.7 mm). The overall distance of superior migration in 24 hips was 0-10 mm (average, 3.7 mm). A single massive bone graft using extracted femoral head was considered to be better than bone fragments as the procedure for acetabular reconstruction during bipolar hip arthroplasty in rheumatoid arthritis.

The lateral approach compared with the volar approach for exposure of the hook of the hamate.

Two cases of delayed union of the hook of the hamate were satisfactorily treated by excisional surgery. The volar surgical approach through the palm is common, but to expose the hook some hypothenar muscles and cardinal ligaments must be divided. Care must be taken to avoid injury of the motor and sensory branches of the ulnar nerve that occur close to the hook. The lateral approach between the abductor digiti minimi muscle and the fifth metacarpal bone is easier and less traumatic. This approach is also safer for the ulnar neurovascular bundle, which is protected by volar retraction and the hypothenar muscles. The lateral approach is advantageous unless the injury is complicated by ulnar nerve palsy or flexor tendon injury.

Grafted bone used in acetabular reconstruction: assessment by SPECT scintigraphy

ObjectiveTo investigate incorporation of the grafted bone used for acetabular reconstruction.DesignSingle photon emission computed tomography (SPECT) was carried out at the 1st, 6th, and 12th month after the operation and the uptakes on serial SPECT scintigrams were normalized. The horizontal histogram of scintigraphic activity at the level of the central grafted bone in the coronal image was designated the profile curve.PatientsSeven patients who had undergone bipolar hip arthroplasty for osteoarthritis of the hip were randomly selected.Results and conclusionFive of seven profile curves obtained at the 1st month demonstrated a single peak at the host-graft junction. The profile curve obtained at the 6th month showed two peaks at the host-graft junction and the periphery of the grafted bone in all patients. The profile curve at the 12th month showed slightly increased activity in the center of the grafted bone. This preliminary study demonstrates that comparison of the serial profile curves on SPECT is valuable in evaluating the progress of incorporation of the grafted bone in hip arthroplasty.

Osteogenesis in xenogeneic bone transplantation, using an immunosuppressant: Rabbit-rat experiments

We investigated osteogenesis and lymphocyte subsets in xenogeneic bone transplantation, using the immunosuppressant FK506 (FK). Iliac bones of rabbits were transplanted as fresh and frozen xenogeneic bone grafts into an intramuscular pouch of rats. FK was injected intramuscularly in half of the rats in a dose of 3 mg/kg/day for 14 days after transplantation. At 2, 4, and 8 weeks, transplanted grafts and the lymphocyte subsets of these rats were examined. In the group not given FK, the grafted bone became necrotic and infiltrated with small round cells around the trabeculae. In the FK group, at 2 and 4 weeks, new bone was formed in the fresh xenografts without infiltration of lymphocytes. At 8 weeks, the new bone became necrotic and lymphocytes were present. The percentage of T cells (CD 5), B cells and the ratio of CD 4 cells/CD 8 cells were smaller in the FK group. Using an immunosuppressant we concluded that xenogeneic bone has an osteogeneic potency.

Experimental study of drainage and granulation in response to the intra-articular injection of particles in rat knee joints

Reactive granulation and drainage of intraarticularly injected plastic particles in rat knee joints was examined by light and electron microscopy. The knee joints and associated iliac lymph nodes were excised at various intervals after the injection of latex beads (ϕ1 μm) or fluoresbrite particles (ϕ0.2 μm or ϕ10 μm) from 5 min until 3 months after the injection. Particles in the lymphatic or blood vessels were successfully demonstrated by an enzyme-histochemical method (5′-nucleotidase staining). Five min after the injection, most of the particles were scattered on the surface of the synovial membrane, and some particles were phagocytosed by synovial lining cells. After 5 h, neutrophils had phagocytosed particles which adhered to fibrin in the joint cavity. Twelve h after the injection, after the neutrophils had died, those same particles were phagocytosed by macrophages in the joint cavity. One day after the injection, Fluoresbrite particles (ϕ0.2 μm) phagocytosed by macrophages were found in the iliac lymph nodes, while latex particles (ϕ1 μm) were detected in the iliac lymph nodes 3 days after the injection. Some Fluoresbrite particles (ϕ10 μm) were seen in the 5′-nucleotidase-positive lymphatic vessels in the synovial membrane. Three months after the injection, many macrophages filled with particles had formed granulation tissue in the synovial membrane, and macrophages containing phagocytosed particles were also seen increasingly in the iliac lymph nodes. Our findings suggested that neutrophils and macrophages phagocytosed injected particles in the joint cavity, and that the macrophages brought the particles into the deep layer of the synovial membrane. Phagocytic macrophages also carried the particles to the iliac lymph nodes through lymphatic vessels in the synovial membrane. There were no morphological differences in the processes of granulation and drainage between the two different sized plastic particles (ϕ1 μm and ϕ0.2 μm), except for the behavior of the macrophages phagocytosing the particles.