1,721,055 research outputs found
Healing and differentiation of human osteoblasts on titanium-zirconia composite material: the effect of different brazing fillers
No full textEvidence of type II estrogen receptor in human osteoblast-like cells
No full textOsteoblast-like cells isolated from human bone bioptic specimens were characterized and analysed for the presence of type II estrogen receptor (type II EBS). The amount of type II EBS was measured by a whole-cell assay at 4 °C for 2.5 h using [3H]-estradiol as tracer. Saturation analysis, used to investigate the binding characteristic of type II EBS, resulted in a sigmoid curve. Scatchard analysis showed the binding affinity of the estrogen receptor, yelding a concave plot. The dissociation constant (K(d)), determined from the [3H]-estradiol concentration required for half saturation was about 12 ± 2 nM (SD). The number of type II EBS, estimated at maximum binding, was 197,000 ± 8800 sites per cell. If the regulation of the receptor by flavonoids would be confirmed, the evidence of type II EBS in osteoblast-like cells could suggest a direct action of ipriflavone and others flavonoids on bone density in postmenopausal osteoporosis
The distribution of ?-2-macroglobulin (alfa2M) on the surface of serum free cultured Swiss 3T3 fibroblasts. A scanning electron microscopy (SEM) and immunohistochemical study
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Characterization of cultured human ligamentum flavum cells in lumbar spine stenosis
No full textTo investigate the pathogenesis of the degenerative changes of the ligamentum flavum occurring in lumbar spine stenosis, yellow ligament cells from patients with lumbar spine stenosis were cultured for the first time and subjected to biochemical, histochemical and immunohistochemical study. Stenotic ligamentum flavum (SLF) cells were seen to express high levels of alkaline phosphatase (ALP) activity and to produce a matrix rich in type I and III collagen, fibronectin and osteonectin, The matrix mineralized only following beta -glyceroghosphate (beta GP) and ascorbic acid supplementation. Stimulation with human parathyroid hormone (PTH) increased intracellular cAMP concentration. These findings indicate that then was significant evidence of osteoblast-like activity in these cells. SLF cells also stained for S100 protein, type II and type X collagen, and co-localized type 11 collagen and ALP labelling, reflecting the presence of hypertrophic chondrocyte-like cells. Cultures from control patients showed neither osteoblastic nor chondrocytic features: they expressed type I and type III collagen and fibronectin. but did not stain for osteonectin, nor were bone-like calcifications observed in presence or absence of beta GP. Normal ligamentum flavum (NLF) cells did not synthesized S100 protein or type II or type X collagen, and showed a weaker response to PTH stimulation. Our data demonstrated the presence of hypertrophic chondrocytes with an osteoblast-like activity in the ligamentum flavum of patients with spinal stenosis suggesting that they could have a role in the pathophysiology of the heterotopic ossification of ligamentum flavum (OLF) in lumbar spine stenosis. (C) 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved
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