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Biomedical subjects

T Sakou

Publications and source records attributed to T Sakou.

86 records · Page 5Linked to original sources
PubMedDate not supplied

Occipitocervical fusion by Luque loop rod instrumentation in Down syndrome.

Four children with Down syndrome who had developed atlantoaxial dislocation and myelopathy underwent occipitocervical fusion with Luque loop rod instrumentation and decompressive laminectomy of C1. The postoperative results are presented and the indications discussed. This procedure provides many advantages in the surgical treatment of Down syndrome compared with the conventional procedures, because of the associated mental retardation that makes the postoperative management very complicated.

Atlanto-Axial Joint↗
PubMedDate not supplied

Optimum duration of oral adjuvant chemotherapy of HCFU for colorectal cancer; review of 5-year follow-up.

PURPOSE: To investigate the optimal duration of oral HCFU administration for minimization of side effects induced by long-term administration. PATIENTS AND METHODS: In total, 155 patients allocated to two groups of different duration of the therapy were reviewed: twice or three times per day doses of oral HCFU (8 mg/Kg body weight/day) for 3 months vs. 12 months. RESULTS: Though statistically significant difference was not found in cumulative survival and disease-free rates between the groups due to so many violations of duration of therapy, when reanalyzing the variables in order of real duration of therapy, those rates were significantly higher in patients treated for 300 and more days than less than 300 days (g-Wilcoxon test: p < 0.04). No significant difference was observed in the background factors between the groups. CONCLUSION: At least 300 days is suggested to be necessary to obtain the optimal effectiveness of adjuvant chemotherapy for curatively resected colorectal cancer.

Administration, Oral↗
PubMedDate not supplied

Transoral atlantoaxial anterior decompression and fusion.

Two patients with atlantoaxial dislocation (one with an accompanying basilar impression) were treated by a combination of transoral anterior decompression and anterior fusion with good results. Transoral odontoidectomy is hazardous and difficult. However, modern high-speed drills increase the safety and diminish the difficulty of the procedure. If the displacement is irreducible and significant, removal of the protruding odontoid process is considered essential for relief of myelopathy. Simultaneous anterior fusion eliminates the necessity of a second operation, i.e., posterior fusion for stabilization of the atlantoaxial region.

Adult↗
PubMedDate not supplied

Immunohistochemical studies on tenascin in human yellow ligament.

The expression of tenascin in yellow ligaments of 67 males and 26 females was investigated by immunohistochemistry. Positive tenascin staining was observed in matrices around fibroblasts of entheses, particularly in transitional regions between the cartilage and ligament in yellow ligaments, in 38 (57%) of 67 males and in 13 (50%) of 26 females examined. The incidence of positive tenascin staining was 62.5, 60.0 and 50.0% of yellow ligaments obtained from cervical, thoracic and lumbar spines, respectively. There were no significant differences in sex or regions examined. The incidence of positive tenascin staining in yellow ligaments of patients between the ages of 10-29 years, 30-49 years, 50-69 years, 70-80 years was 29, 55, 69 and 40%, respectively. The incidence of positive tenascin staining in yellow ligaments obtained from patients with ossification in posterior longitudinal ligaments and yellow ligaments and from patients with other diseases such as lumbar disc hernition, cervical spondylosis or spinal tumors was 80.0 and 47.9%, respectively. These results show that the appearance of tenascin in ligaments varies with aging and is frequent in spinal diseases with ossification.

Adolescent↗
PubMedDate not supplied

Expression and distribution of transforming growth factor-beta and decorin during fracture healing.

To study interactions between TGF-beta and decorin, we experimentally induced femoral fracture in rats and immunohistologically examined changes in the distribution of TGF-beta and decorin in the femur 3, 7 and 14 days after fracture. In the areas where endochondral ossification occurred, decorin was detected during differentiation of mesenchymal cells into proliferating chondrocytes, while no TGB-beta was observed during same period. Once chondrocytes had hypertrophied, decorin was no longer observed, while the matrix around the hypertrophic chondrocytes was positively stained for TGB-beta. The disappearance of decorin, almost simultaneously accompanied by the appearance of the active type TGB-beta, suggests that decorin regulates the actions of TGB-beta.

Animals↗
PubMedDate not supplied

Histochemical and immunohistochemical study on the skin of patients with ossification of the posterior longitudinal ligament in the cervical spine.

We present an immunohistochemical study on extracellular matrix (ECM), decorin, in the epidermis and dermis of patients with ossification of the posterior longitudinal ligament (OPLL) to clarify the abnormality in the extracellular matrix of the skin of OPLL. Localization of decorin and TGF-beta in the skin was studied. All patients with OPLL showed a diffuse strong staining of decorin in the entire epidermal layer. The epidermis was also positive for TGF-beta antibody staining. Patients with cervical spondylotic myelopathy showed weak or no staining of decorin. Abnormality in the regulating system of TGF-beta may be involved in the precipitation of extracellular matrix.

Aged↗
PubMedDate not supplied

Osteogenesis by pulsing electromagnetic fields (PEMFs): optimum stimulation setting.

The optimum setting for electromagnetic stimulation was examined by histologically assessing the degree of osteogenesis at different settings of electromagnetic stimulation, and comparing alkaline phosphatase (ALP) activity in the bone marrow. For this experiment, an electromagnetic field generator manufactured by the Institute of Physical and Chemical Research was used. The intensity of the magnetic field was set at eight levels; 0.1, 0.2, 0.4, 1, 2, 4, 6 and 8 gauss (G). The frequencies used were 5, 10, 20, 50, 100 and 200 Hz. Pulse durations were 6, 12, 25, 50 and 100 micro sec. Significant ALP elevation and osteogenesis were observed at magnetic field intensities of 0.4, 1, and 2G. ALP activity did not differ between different frequencies. ALP activity at pulse durations of 25 and 50 micro sec were significantly higher than at the other pulse durations. The effect of electromagnetic stimulation on osteogenesis greatly depends on the intensity and pulse duration of the stimulation.

Alkaline Phosphatase↗
PubMedDate not supplied

Expression of decorin mRNA in the skin of patients with ossification of the posterior longitudinal ligament.

Ossification of the posterior longitudinal ligament (OPLL) is an intractable disease developing into severe myelopathy and often accompanied by ossification of several other spinal ligaments and articular ligaments. Therefore, it is highly probable that predisposition to systemic ossification underlies the onset of this disease. Terayama et al(1981) reported that the nuchal skin of OPLL patients tended to be tougher than that of healthy individuals. Decorin is a component of the extracellular matrix which antagonistically regulates the action of Transforming growth factor-beta (TGF-beta). Imamura et al(1995) demonstrated immunohistochemically that decorin increased in the epidermis of the nuchal skin of OPLL patients. This suggests an abnormal expression of the extracellular matrix in the skin of OPLL patients. In the present study, in situ hybridization with non-radioactive synthetic oligodeoxynucleotide probes revealed an enhanced expression of decorin mRNA in the epidermal keratinocytes of OPLL patients. The increased expression of decorin mRNA in the epidermis of OPLL patients may be interpreted as reflecting abnormalities of the matrix associated with ossification of the ligaments. Studies on the role of decorin in ossification will contribute to clarification of the pathophysiology and pathogenesis of OPLL.

Adult↗
PubMedDate not supplied

The effect of pulsing electromagnetic field on bone ingrowth into a porous coated implant.

Electromagnetic stimulation is known to promote bone formation in cases of fracture and pseudoarthrosis. The possibility of using electromagnetic field to promote bone ingrowth into a porous coated implant was investigated in this study using Japanese albino rabbits. A titanium implant coated with beads of 250-300 microns in diameter around a stem of 1.7 mm in diameter was inserted into the humerus cavity of a Japanese albino rabbit. The humerus was stimulated by pulsing electromagnetic fields at 2 Gauss, 10Hz, 25 microseconds for 14 days. The circumference of grown bone into the implant was measured, and calculated in area equivalent for determination of the area of new bone. Bone ingrowth was significantly promoted by consecutive 14 days. The result suggests that electromagnetic stimulation is useful for achieving further bone ingrowth into a porous coated implant.

Animals↗
PubMedDate not supplied

Immunohistochemical localization of bone morphogenetic proteins and the receptors in epiphyseal growth plate.

The expression of bone morphogenetic proteins (BMPs) and BMP receptors (BMPRs) in the epiphyseal growth plate has not been clarified. In this study, we studied immunohistochemically the spatial and temporal localization of BMP-2/4, osteogenic protein-1 (OP-1, or BMP-7), and BMP receptors (BMPR-IA, BMPR-IB, and BMPR-II) in the epiphyseal plate of growing rats. The proximal parts of tibia in growing rats were observed. At 12 weeks after birth, BMP-2/4 and OP-1 were expressed markedly in proliferating and maturing chondrocytes. BMPR-IA, IB and II were clearly co-expressed in proliferating and maturing chondrocytes, and the expression was decreased in hypertrophic chondrocytes. At 24 weeks, the expression of BMP-2/4 and OP-1 was decreased, but BMPRs were still well-expressed in proliferating chondrocytes. The temporal and spatial expression of BMP and BMPR suggests that BMP and BMP receptors play roles in the multistep cascade of enchondral ossification in the epiphyseal growth plate.

Aging↗
PubMedDate not supplied

Retinoid and bone metabolic marker in ossification of the posterior longitudinal ligament.

The pathogenesis of ossification of the posterior longitudinal ligament (OPLL) remains to be elucidated, though etiologic factors for OPLL have been identified. High levels of serum retinol and retinol binding protein (RBP) have been observed in patients with diffuse idiopathic skeletal hyperostosis (DISH). OPLL is often associated with DISH. In this study, the levels of serum retinol and RBP were determined in 70 patients with OPLL in the cervical spine, and compared with those in normal subjects. Bone metabolic markers of serum intact osteocalcin, urinary pyridinoline and deoxypyridinoline were examined as well. Among female patients, level of serum RBP was significantly higher in those in their 60's, and those with mixed type OPLL. Level of serum RBP was significantly higher in both sexes, and retinol was exhibited higher in female patients, if they were associated with DISH. Patients with OPLL exhibited no abnormal bone metabolic marker levels. These findings suggest that vitamin A may play a role in the development of OPLL.

Adult↗
PubMedDate not supplied

The spatial and temporal immunolocalization of TGF-beta 1 and bone morphogenetic protein-2/-4 in phallic bone formation in inbred Sprague Dawley male rats.

In male rats and mice, the membranous bone is rapidly formed in the proximal segment (p-segment) of the os penis, and then endochondral ossification proceeds in the proximal half. The spatial and temporal patterns of expression of transforming growth factor-beta 1 (TGF-beta 1) and bone morphogentic protein-2/-4 (BMP-2/-4) were examined immunohistochemically until 14 days after birth and compared. BMP-2/-4 expression was weak in the mesenchymal condensation just at birth, and up-regulated in the membranous bone and cartilage 3 days after birth. BMP-2/-4 was strongly expressed in proliferating and mature chondrocytes 7 days after birth. At birth, TGF-beta 1 expression was diffuse and very strong in mesenchymal condensation. Thereafter, TGF-beta 1 expression was continuously strong in membranous bone and cartilage. Seven days after birth, TGF-beta 1 was actively expressed in proliferating chondrocytes. TGF-beta 1 and BMP-2/-4 seemed to act co-operatively. In particular, TGF-beta 1 appeared to strongly regulate immature stage and BMP-2/-4 may regulate the mature stage.

Animals↗
PubMedDate not supplied

Immunolocalization of transforming growth factor-beta s and type I and type II receptors in rat articular cartilage.

The activities of TGF-beta s and their receptors (T beta R) in the articular cartilage have not been fully elucidated as yet. Temporal and spatial expression of TGF-beta s and their receptors were examined immunohistochemically in the articular cartilage of growing rats to clarify their role in chondrogenesis. TGF-beta 1, -beta 2 and -beta 3 were strongly expressed from 6 to 50 weeks in the superficial, transitional, and least mature zones. The expression of TGF-beta s in hypertrophic chondrocyte was weak except TGF-beta 1. T beta R-I and T beta R-II were co-expressed with the ligand in the superficial, transitional, and least mature zones throughout the growth phase. This study revealed that TGF-beta s in the articular cartilage plays a major role in the modulation of endochondral ossification ensuring the growth and maintenance of the chondrocyte lineage in articular cartilage.

Activin Receptors, Type I↗