Biomedical subjects

E Chosa

Publications and source records attributed to E Chosa.

6 recordsLinked to original sources

PubMed2002

Adrenomedullin stimulates the growth of cultured normal human osteoblasts as an autocrine/paracine regulator.

Adrenomedullin (AM) is a 52 amino acid peptide that is synthesized in a variety of tissues, including the vessels and bones. This study showed that normal human osteoblast (NHOst) secreted immunoreactive AM and that AM stimulated intracellular cAMP production in these cells. An anti-AM monoclonal antibody, which inhibited endogenous AM, caused the number of NHOst to decrease. The effect of a low concentration AM was inhibited by addition of a cAMP-dependent protein kinase A inhibitor (H89). These data suggest that AM is an autocrine or paracrine regulator that promotes the proliferation of NHOst via the cAMP pathway.

Adrenomedullin↗

PubMed2001

Biochemical and morphological changes in herniated human intervertebral disc.

The molecular and morphologic features of herniated human intervertebral disc tissues are of particular importance to clarify the pathogenesis. The present study analyzed the biochemical and morphological features of herniated intervertebral disc tissues to determine the constituent factors responsible for intervertebral disc herniation. A total of 32 herniated disc specimens and 4 control disc samples were analyzed. Collagen subunit composition, collagenase activity, lipid peroxidation level, caspase-3 activity, metal levels, morphologic studies, and genetic analysis were performed on herniated disc tissues of chronic (group A) and acute (group B) group and compared with findings of control group. Nick translation analysis in situ revealed apoptotic-positive stained DNA fragments as black-brown spots in herniated disc tissues. The presence of type II collagen in control disc samples and its absence in herniated samples were confirmed immunohistochemically. The increased caspase-3 activity, the apoptotic-positive stained DNA fragments, and the electron microscopic findings suggest enhanced programmed cell death in herniated discs. The significant increase in lipid peroxidation levels and collagenase activity, and the low metal levels suggest the enhancement of cell death signals in herniated discs, caused by oxygen stress. Linkage analysis of herniated disc tissues in Japanese individuals may suggest ethnic variation. These findings may be helpful in understanding the pathogenesis of herniated disc disease.

Adolescent↗

PubMed2000

Biomechanical analysis of effects of foot placement with varying chair height on the motion of standing up.

Individual experience reveals that posterior foot placement enables one to stand up easily from a chair. However, the way in which foot placement affects this motion has not been investigated in detail. This study was performed to examine the effects of foot placement in the initial stage of the dynamics of standing up from a chair. Subjects wearing light-emitting diode markers and surface electrodes stood up from a chair over force plates, and ground reaction force, joint angle, and muscle activity were measured. The motions required to stand up from chairs 30, 40, or 50 cm in height were analyzed with anterior, vertical, and posterior foot placement. With anterior foot placement, the forward-acceleration components of the ground reaction force were recorded with simultaneous and long-sustained activity of the muscles in order to shift the center of gravity of the body forward even more after lift-off. Our findings indicate that the distance between the center of gravity and the point of application of ground reaction force at lift-off are critical factors in the standing-up motion, and that chairs should be of adequate height as well as having sufficient space under the seat to permit the backward movement of the lower legs.

Activities of Daily Living↗

PubMed1999

A biomechanical study of posterolateral lumbar fusion using a three-dimensional nonlinear finite element method.

Biomechanical analyses under compressive load, flexion, and extension torque were performed, using a nonlinear three-dimensional finite element method, to evaluate stability in posterolateral fusion. Effects of facet fusion and disc denucleation on posterolateral fusion were also examined. Using an initially prepared L4-5 motion segment model, we prepared a denucleation model, posterolateral fusion models classified by presence or absence of denucleation and facet fusion, and an interbody fusion model. In the denucleation model, rigidity was less than in the normal model, and maximum rigidity was analyzed for the interbody fusion model. The effect of denucleation on posterolateral fusion was also analyzed. Taking into account the instability of the anterior elements, including the intervertebral disc, appears to be clinically important. In the posterolateral fusion model under compressive load, the axis of rotation moved principally toward the fusion mass, and axial displacement and flexion rotation were induced. Sagittal rotation angles under flexion and extension torque were 1.5 degrees -2.3 degrees at a maximum moment of 15 N-m, demonstrating elasticity of posterolateral fusion. When combined with facet fusion, posterolateral fusion yielded increase of load transfer across the lamina and decrease of rotation angle of about 10% under flexion-extension torque. Adjunctive clinical use of facet fusion should permit more solid posterolateral fusion.

Biomechanical Phenomena↗

PubMed1999

Segmental square spinal instrumentation for posterior lumbar spinal fixation.

The purpose of this study is to evaluate the clinical results of operations using a new spinal instrumentation for posterior fixation, called segmental square spinal (3-S) instrumentation. The 3-S instrument consists of two pairs of hooks to clasp the interarticular portion of the lamina bilaterally, two horizontal bars to connect the hooks on the right and left, and rods to connect the hooks side by side on the top and bottom. Twenty-seven patients who had degenerative lumbar disorders underwent operations with the 3-S instrument. Rigid fixation was obtained in all cases immediately after the operation. Bone union rates were 91% (21/23) with posterolateral fusion. The 3-S instrument seems to be suitable for spinal disorders in which anterior spinal fusion is not necessary, especially for degenerative spinal disorders.

Adult↗

PubMed1998

A cement spacer for two-stage revision of infected implants of the hip joint.

We report the technical details and clinical results of twelve patients who had deep infections of implants in the hip joint and were treated by two-stage revision, using a gentamicin-loaded, hand-moulded cement spacer inserted for the period between resection and reimplantation arthroplasty. During management with the spacer, usually for 4 months, patients were almost free of pain and mobile with good leg control, spending 2/3 of the treatment period at home. Six of twelve spacers failed locally due to dislocation [5] or cement fracture [1], and more than two further episodes of surgery were required in 3 patients. Problems with dislocation of the spacer were significantly higher when the head to neck offset was lacking (P < 0.05) or when anchorage in the femoral shaft was poor. Nevertheless, infection after reimplantation arthroplasty did not occur by the time of follow-up (2.2 years). Based on these data, we consider that the use of the cement spacer is a promising approach to the treatment of complicated infections of the hip joint.

Aged↗