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  • 1
    Electronic Resource
    Electronic Resource
    Adhesion, growth, and matrix production by osteoblasts on collagen substrata (1992)
    Springer
    Calcified tissue international 51 (1992), S. 202-212 
    Details
    ISSN: 1432-0827
    Keywords: Osteoblasts ; Collagen type I ; “On gel” cultures ; Collagen sponges ; Osteocalcin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A number of studies have demonstrated the pivotal role of collagen molecules in modulating cell growth and differentiation. In order to analyze the direct effects of collagen type I on the osteoblastic phenotype, we have devised an in vitro culture system for studying the interactions between bovine collagen type I and Saos-2 cells, a human osteoblastic cell line. Saos-2 cells were cultured both on top of collagen-coated culture dishes as well as inside a three-dimensional collagen network. Plating on dishes treated with collagen induced maximal adhesion of Saos-2 cells after 24-hour incubation. Cells cultured on collagen gel matrix expressed about 2.5-fold more alkaline phosphatase when compared with untreated plastic dishes. On collagen-coated dishes the responsiveness of Saos-2 cells to parathyroid hormone was decreased, whereas no modifications were observed in the effect of vasoactive intestinal peptide on these cells. Using a microfluorimetric measurement of DNA, an increase of proliferation was observed in Saos-2 cells cultured on collagen gel Saos-2 cells were also able to colonize collagen sponges and in this three-dimensional network they were able to synthesize osteocalcin, as assessed both by immunocytochemistry and radioimmunoassay. In this study we have demonstrated that bovine collagen type I exhibits favorable effects on attachment and functional and growth activities of a human osteoblastic cell line, encouraging its use as a bone graft material.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334548
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  • 2
    Electronic Resource
    Electronic Resource
    Comparison of Quantitative Calcaneal Ultrasound and Dual Energy X-ray Absorptiometry in the Evaluation of Osteoporotic Risk in Children with Chronic Rheumatic Diseases (2000)
    Springer
    Calcified tissue international 67 (2000), S. 19-23 
    Details
    ISSN: 1432-0827
    Keywords: Key words: Broadband ultrasound attenuation — Contact ultrasound bone analyzer — Bone mineral density — Dual energy X-ray absorptiometry — Chronic rheumatic diseases.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. Osteoporosis is a common complication in children with chronic rheumatic diseases (CRD). Although dual energy X-ray absorptiometry (DXA) is increasingly being used to determine bone mineral density (BMD) in children, it exposes the subject to ionizing radiation and does not provide a measure of true bone density; in fact, in growing bones the increase in BMD is mainly caused by the increase in bone size. In recent years, quantitative ultrasound techniques (QUS) have been used in radiation-free assessment of bone density and ``bone quality'' by measurement of the ultrasound waves attenuation by bone (BUA). In the present study we made a direct comparison of BUA in the calcaneum, determined by the pediatric contact ultrasound bone analyzer (CUBA) with lumbar BMD measured by DXA, in a group of 6–18-year-old patients with CRD. The study group consisted of 53 patients affected with juvenile rheumatoid arthritis (n = 29), systemic lupus erythematosus (n = 13), and juvenile dermatomyositis (n = 11). Mean age was 13.02 ± 2.69 years. In 22 patients (19 girls, 3 boys) both DXA and CUBA were repeated after 1 year in order to assess the mean percentage rate of BMD and BUA change over this time. Both lumbar spine BMD and calcaneal BUA measurements were lower in the CRD patients compared with a control group (P 〈 0.001). Calcaneal BUA was significantly correlated (r = 0.83, P 〈 0.001) with lumbar spine BMD. Age and sex correction (Z-score) did not change the relationship between BUA and BMD (r = 0.80, P 〈 0.001). A significant correlation between the mean percentage of variation (Δ%) of BMD and BUA (r = 0.76, P 〈 0.001) was also demonstrated in the 22 patients who were evaluated prospectively. Portability, ease of use, lower cost, and absence of radiation make CUBA a promising means of evaluating BMD in children.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00223001090
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  • 3
    Electronic Resource
    Electronic Resource
    Vitamin D Receptor Genotypes and Intestinal Calcium Absorption in Postmenopausal Women (1997)
    Springer
    Calcified tissue international 61 (1997), S. 460-463 
    Details
    ISSN: 1432-0827
    Keywords: Key words: VDR genotypes — Intestinal Ca absorption — Osteoporosis genetics — Strontium chloride — Postmenopausal women.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. Several studies have shown that bone mass and bone turnover are genetically determined. This genetic component is thought to be mediated in part by polymorphisms at the vitamin D receptor (VDR) locus, even though the underlying molecular mechanisms are still unknown. To evaluate a possible site of differential action of the VDR gene alleles we examined their correlation with intestinal calcium absorption in 120 Caucasian postmenopausal women (aged 61 ± 0.6 years). VDR gene polymorphisms for Apa I, Bsm I, and Taq I restriction endonucleases were assessed by Southern blotting analysis. The most common genotypes observed in our population were AaBbTt (37%), AABBtt (20%), aabbTT (15%), AabbTT (15%), and AABbTt (9%). Although there was some evidence of 13% higher lumbar BMD values in aabbTT genotype with respect to AABBtt genotype, this difference of approximately 0.1 g/cm2 did not reach statistical significance, possibly because of the limited number of observations. On the contrary, no relationship was found between genotypes and femoral neck BMD values. Intestinal calcium absorption was significantly lower in BB and tt genotypes than, in bb and TT genotypes, respectively, and in AABBtt genotype than in either aabbTT or AaBbTt genotypes (P= 0.0015 ANOVA). No significant differences in intact PTH, alkaline phosphatase, 25OHD3, and 1,25(OH)2D3 were found among subjects with different VDR genotypes. These results are consistent with a possible role of VDR alleles on intestinal calcium absorption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002239900368
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  • 4
    Electronic Resource
    Electronic Resource
    Identification of hazelnut (Corylus avellana) cultivars by RAPD analysis (1999)
    Springer
    Plant cell reports 18 (1999), S. 652-655 
    Details
    ISSN: 1432-203X
    Keywords: Key words PCR ; RAPD analysis ; Corylus avellana ; Cultivars
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The random amplified polymorphic DNA (RAPD) technique offers a useful tool to detect DNA polymorphisms. It can also be used to distinguish different clones and cultivars. We have developed a comprehensive RAPD-based procedure for the routine molecular typing of various plants. Here we report the application of this technique for the correct identification of six hazelnut cultivars (Corylus avellana) widespread in the Campania region (south Italy). The analysed hazelnut cultivars were successfully distinguished by their RAPD fingerprints using the DNA primers U2, U3, U4, U11 and U14. However, in each cultivar we observed very low genetic heterogeneity among the clonal variants. Since this technique is among the simplest and easiest methods used to fingerprint DNA, it could be easily transferred to less sophisticated laboratory infrastructures (e.g. outstations of crop regulatory agencies).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002990050637
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  • 5
    Electronic Resource
    Electronic Resource
    Role for autocrine TGF-β1 in regulating differentiation of a human leukemic cell line toward osteoclast-like cells (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 160 (1994), S. 482-490 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Increasing evidence suggests that transforming growth factor-β (TGF-β) is involved in bone formation during remodeling. Using a recently cloned human leukemic cell line (FLG 29.1 cells) we demonstrate that these cells synthesize and secrete TGF-β1 and that exogenous or autocrine TGF-β1 can induce the same features of osteoclastic-like cells, exerting its effects through the binding to TGF-β specific receptors. Scatchard analysis of 125I-labeled TGF-β1 to FLG 29.1 cells revealed the presence of a single high affinity binding site with a Kd value of ∼25 pM and a binding capacity of ∼900 sites/cell. Affinity labeling experiments showed that FLG 29.1 cells express type I and type II TGF-β receptors. Stimulation of FLG 29.1 cells with low TGF-β1 doses reduced cell proliferation and increased cell adhesion and tartrate resistant acid phosphatase (TRAcP) activity. Pretreatment of FLG 29.1 cells with TGF-β1 caused a significant and dose-dependent response to calcitonin. Northern blot of total mRNA and analysis of the conditioned media (CM) showed that TGF-β1 was synthesized by FLG 29.1 cells. TPA treatment, which induces partial differentiation of these cells, markedly increased TGF-β1 mRNA expression and growth factor release. The majority of TGF-β1 secreted by TPA-treated cells was in its latent form. However, anti-TGF-β antibodies inhibited TGF-β1 and TPA-induced growth inhibition, calcitonin responsiveness, and TRAcP activity, suggesting that the TPA effect is mediated in part by autocrine TGF-β1 and indicating that the cells can activate and respond to the TGF-β that they secrete. These findings support a potential autocrine role for TGF-β1 in osteoclast differentiation. © 1994 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041600311
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