20 research outputs found
Induction of abundant osteoclast-like multinucleated giant cells in adjuvant arthritic rats with accompanying disordered high bone turnover
The development of an in vivo system for investigating osteoclast differentiation is important because molecular events occurring in vivo can be observed during the differentiation of the authentic osteoclasts. In adjuvant arthritic rats, an experimental model of human rheumatoid arthritis, extensive bone resorption is observed in the distal diaphysis of the tibia. In the area of extensive bone resorption, it is always accompanied with clusters of numerous multinucleated giant cells (MGCs) as well as bone-resorbing osteoclasts. Here we characterized the morphological properties of these MGCs with the use of enzymehistochemical and immunohistochemical techniques. Extensive destruction but also a marked formation of the inner and outer bone surfaces were the predominant features in the tibiae of such arthritic rats 4 weeks after the adjuvant injection. Numerous MGCs were frequently clustered in the bone marrow spaces located apart from the bone matrices. Although the MGCs lacked ruffled borders, these cells were rich in mitochondria and vacuoles. These multinucleated cells revealed a positive reaction for tartrate-resistant acid phosphatase but a negative reaction for non-specific esterase staining. Most of these MGCs expressed the Kat l-antigen, an immunological marker specifically expressed on the cell surface of rat osteoclasts. In a dentin resorption experiment using a cluster of MGCs excised from the bone marrow tissues of the tibial distal diaphyses of rats with adjuvant arthritis, many resorption lacunae were formed on dentin slices after a 3-day culture. These results suggest that the majority of the MGCs are osteoclasts but not macrophage polykaryons
Induction of abundant osteoclast-like multinucleated giant cells in adjuvant arthritic rats with accompanying disordered high bone turnover
The development of an in vivo system for
investigating osteoclast differentiation is important
because molecular events occurring in vivo can be
observed during the differentiation of the authentic
osteoclasts. In adjuvant arthritic rats, an experimental
model of human rheumatoid arthritis, extensive bone
resorption is observed in the distal diaphysis of the tibia.
In the area of extensive bone resorption, it is always
accompanied with clusters of numerous multinucleated
giant cells (MGCs) as well as bone-resorbing osteoclasts.
Here we characterized the morphological
properties of these MGCs with the use of enzymehistochemical
and immunohistochemical techniques.
Extensive destruction but also a marked formation of
the inner and outer bone surfaces were the predominant
features in the tibiae of such arthritic rats 4 weeks after
the adjuvant injection. Numerous MGCs were
frequently clustered in the bone marrow spaces located
apart from the bone matrices. Although the MGCs
lacked ruffled borders, these cells were rich in
mitochondria and vacuoles. These multinucleated cells
revealed a positive reaction for tartrate-resistant acid
phosphatase but a negative reaction for non-specific
esterase staining. Most of these MGCs expressed the
Kat l-antigen, an immunological marker specifically
expressed on the cell surface of rat osteoclasts. In a
dentin resorption experiment using a cluster of MGCs excised from the bone marrow tissues of the tibial distal
diaphyses of rats with adjuvant arthritis, many
resorption lacunae were formed on dentin slices after a
3-day culture. These results suggest that the majority of
the MGCs are osteoclasts but not macrophage
polykaryon
Photoelastic Measurements of Polymer Insert Stress in the Knee Prostheses Designed for High/Deep Flexion
This paper presents the experimental results of photoelasticity for determining the magnitude and distribution of stresses on the polyethylene insert of the knee prostheses designed for high/deep knee flexion. The prostheses used in our experiment were a conventional posterior stabiliser knee, Scorpio NRG (Non-Restricted Geometry, Stryker Co., USA) and CFK (Complete Flexion Knee, Japan Medical Material Co., Japan), which we have developed to enable the patient to make a complete knee flexion (i.e. seiza in Japanese). Prior to the photoelastic experiment, we had introduced the forces exerted on the knee joint during ascending from deep knee flexion. Here we took squatting as an example of deep knee flexion instead of seiza because ascending from seiza contains complex modalities. The introduced data in terms of knee angles and joint forces were applied to the photoelastic models. The results demonstrated that after the knee angle became larger than 90°, the shear stresses on the post and cam of NRG were higher than those on the ball and socket of CFK. We conclude that the design and the configuration of CFK is acceptable at deep knee flexion from a load-bearing viewpoint
Photoelastic Measurements of Polymer Insert Stress in the Knee Prostheses Designed for High/Deep Flexion
This paper presents the experimental results of photoelasticity for determining the magnitude and distribution of stresses on the polyethylene insert of the knee prostheses designed for high/deep knee flexion. The prostheses used in our experiment were a conventional posterior stabiliser knee, Scorpio NRG (Non-Restricted Geometry, Stryker Co., USA) and CFK (Complete Flexion Knee, Japan Medical Material Co., Japan), which we have developed to enable the patient to make a complete knee flexion (i.e. seiza in Japanese). Prior to the photoelastic experiment, we had introduced the forces exerted on the knee joint during ascending from deep knee flexion. Here we took squatting as an example of deep knee flexion instead of seiza because ascending from seiza contains complex modalities. The introduced data in terms of knee angles and joint forces were applied to the photoelastic models. The results demonstrated that after the knee angle became larger than 90°, the shear stresses on the post and cam of NRG were higher than those on the ball and socket of CFK. We conclude that the design and the configuration of CFK is acceptable at deep knee flexion from a load-bearing viewpoint