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T. M. Skerry M.D. M.R.C.V.S. R. Suswillo A. J. El Haj N. N. Ali R. A. Dodds L. E. Lanyon 《Calcified tissue international》1990,46(5):318-326
Summary Previous studies of Alcian blue-induced birefringence in adult avian cortical bone showed that a short period of intermittent
loading rapidly produces an increased level of orientation of proteoglycans within the bone tissue. In the absence of further
loading, this persists for over 24 hours. We have proposed that this phenomenon could provide a means for “capturing” the
effects of transient strains, and so provide a persistent, constantly updated strain-related influence on osteocyte populations
related to the bones' averaged recent strain history, in effect, a “strain memory” in bone tissue. In our present study, we
use the Alcian blue-induced birefringence technique to demonstrate that proteoglycan orientation also occurs after intermittent
loading of both cortical and cancellous mammalian bonein vivo andin vitro. We also show that the change in birefringence is proportional to the magnitude of the applied strain, and that the reorientation
occurs rapidly, reaching a maximal value after only 50 loading cycles. Examination of electron micrographs of bone tissue
after staining with cupromeronic blue allows direct visualization and quantification of the change in proteoglycan orientation
produced by loading. This shows that intermittent loading is associated with a realignment of the proteoglycan protein cores,
bringing them some 5 degrees closer to the direction of collagen fibrils in the bone matrix. 相似文献
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Indole-3-carbinol and 3,3'-diindolylmethane induce apoptosis in human prostate cancer cells. 总被引:4,自引:0,他引:4
Cruciferous vegetables contain glucobrassicin which, during metabolism, yields indole-3-carbinol (I3C). In a low pH environment I3C is converted into polymeric products, among which 3,3'-diindolylmethane (DIM) is the main one. The apoptotic effects of I3C and DIM were exhibited in human breast cancer cells. The objectives of this study were: (a) examination of the potential effects of I3C and DIM on the proliferation and induction of apoptosis in human prostate cancer cell lines with different p53 status; (b) to try to characterise the mechanism(s) involved in these effects. Our results indicate that both indole derivatives suppress the growth of these cells in a dose- and time-dependent manner, by inducing apoptosis. It appears that these indolic compounds may offer effective means against prostate cancer. Induction of apoptosis was p53-independent. Moreover, the indole derivatives employed did not affect the levels of bcl-2, bax and fasL. 相似文献
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Mechanotransduction of bone cells<Emphasis Type="Italic">in vitro</Emphasis>: Mechanobiology of bone tissue 总被引:11,自引:0,他引:11
Mullender M El Haj AJ Yang Y van Duin MA Burger EH Klein-Nulend J 《Medical & biological engineering & computing》2004,42(1):14-21
Mechanical force plays an important role in the regulation of bone remodelling in intact bone and bone repair. In vitro, bone
cells demonstrate a high responsiveness to mechanical stimuli. Much debate exists regarding the critical components in the
load profile and whether different components, such as fluid shear, tension or compression, can influence cells in differing
ways. During dynamic loading of intact bone, fluid is pressed through the osteocyte canaliculi, and it has been demonstrated
that fluid shear stress stimulates osteocytes to produce signalling molecules. It is less clear how mechanical loads act on
mature osteoblasts present on the surface of cancellous or trabecular bone. Although tissue strain and fluid shear stress
both cause cell deformation, these stimuli could excite different signalling pathways. This is confirmed by our experimental
findings, in human bone cells, that strain applied through the substrate and fluid flow stimulate the release of signalling
molecules to varying extents. Nitric oxide and prostaglandin E2 values increased by between two- and nine-fold after treatment with pulsating fluid flow (0.6±0.3 Pa). Cyclic strain (1000
μstrain) stimulated the release of nitric oxide two-fold, but had no effect on prostaglandin E2. Furthermore, substrate strains enhanced the bone matrix protein collagen I two-fold, whereas fluid shear caused a 50% reduction
in collagen I. The relevance of these variations is discussed in relation to bone growth and remodelling. In applications
such as tissue engineering, both stimuli offer possibilities for enhancing bone cell growth in vitro. 相似文献
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Szalay F Zsarnovszky A Fekete S Hullár I Jancsik V Hajós F 《Anatomy and embryology》2001,203(1):53-59
Piglets born with spread-leg syndrome, a congenital weakness of the hindlimb adductors, were investigated to determine the site of lesion leading to limb impairment. Histological and immunohistochemical studies of the motor neuron unit showed no alterations but quantitative analysis revealed a reduction of axonal diameter and myelin sheath-thickness of the fibres innervating the adductors of the affected limbs. In the lumbar spinal cord a lack of myelination was observed in the tracts descending to the lower motor neurons. Recovery from the syndrome was accompanied by a catching-up of myelination with that of the controls. The spread-leg syndrome is due to a nutritional deficiency in the sow; thus it is assumed that the deficient maternal substances, mainly choline and methionine, are essential for the normal myelin production by spinal white matter oligodendrocytes of the fetus. 相似文献
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Becette V Chérel P Menet E Yacoub S Brain E Hagay C Guinebretière JM 《Annales de pathologie》2003,23(6):496-507
Stereotactic 11-Gauge vacuum-assisted biopsy provides a valuable tool in the diagnosis of mammographically detected breast microcalcifications. However, this new diagnostic technology presents some limitations and requires a close collaboration between radiologists, pathologists and physicians. The aim of this work is to propose a practical approach in the management of large core biopsies and to summarize the different difficulties faced by the pathologist in the management and histological interpretation of specimens issuing from this device. 相似文献