Search results for " Collage"
showing 10 items of 161 documents
Fracture Mechanics of Collagen Fibrils: Influence of Natural Cross-Links
2013
AbstractTendons are important load-bearing structures, which are frequently injured in both sports and work. Type I collagen fibrils are the primary components of tendons and carry most of the mechanical loads experienced by the tissue, however, knowledge of how load is transmitted between and within fibrils is limited. The presence of covalent enzymatic cross-links between collagen molecules is an important factor that has been shown to influence mechanical behavior of the tendons. To improve our understanding of how molecular bonds translate into tendon mechanics, we used an atomic force microscopy technique to measure the mechanical behavior of individual collagen fibrils loaded to failu…
Combined evaluation of resting IGF-I, N-terminal propeptide of type III procollagen (PIIINP) and C-terminal cross-linked telopeptide of type I collag…
2004
To verify whether combined measurements of GH-dependent parameters might be useful in detecting exogenous recombinant GH (rGH) administration in male athletes from different disciplines.Sixty-six athletes (control group) were sampled for the evaluation of resting IGF-I, N-terminal propeptide of type III procollagen (PIIINP) and telopeptide type I collagen (ICTP). Cut-off values (mean + 2 SD) for IGF-I, PIIINP and ICTP were calculated and arbitrary scores (1.5, 2.0) were assigned to abnormal parameters. By using the sum of individual parameter scores, positive (or = 3) or negative (3) scores were obtained. In addition, a subgroup of six athletes was treated for 3 weeks with rGH (0.09 IU/kg b…
Biochemical bone markers compared with bone density measurement by dual energy X-ray absorptiometry
1995
In contrast to medical imaging, the biochemical markers allow a more frequent determination and are not as invasive as histomorphometric methods. We investigated biochemical markers of type I collagen compared with bone density measurements in 85 females between 41 and 89 years of age (median: 57 years). The bone density measurements were performed by dual energy X-ray absorptiometry (DXA) on the lumbar spine (L1-4). The bone density measurements were stated as a percentage of the norm. All patients were divided into three groups: I =80%; II = 80-130%; III =120%. Based on this classification the median concentration of the I-carboxyterminal propeptide of type I collagen in serum (S-PICP) as…
Mobility or migration: a case study from the Neolithic settlement of Nieder-Mörlen (Hessen, Germany)
2009
A combination of stable carbon and nitrogen isotope analysis of collagen and radiogenic strontium isotope analysis of tooth enamel was used to investigate diet and mobility at the early Neolithic settlement of Nieder-Morlen in Germany. The carbon and nitrogen ratios suggest a mixed terrestrial based diet that is consistent with data previously published for early Neolithic sites in Europe. The strontium isotope data indicate a high degree of human mobility with only one individual having an isotope ratio consistent with locally derived strontium. Unusually, a group of non-local juveniles with isotope ratios typical of upland regions is also present at the settlement but there are no adult b…
Dental calculus is not equivalent to bone collagen for isotope analysis: a comparison between carbon and nitrogen stable isotope analysis of bulk den…
2014
Palaeodietary reconstruction using the carbon and nitrogen isotope values of bone and dentine collagen is a well-established method and the biochemical processes involved are well known. Researchers have recently explored using bulk samples of dental calculus as a substitute for bone and dentine collagen in dietary analyses, because calculus can be sampled without causing damage to the teeth, and may be useful in situations where more destructive analyses are not possible, or where collagen is poorly preserved. Several questions remain about the use of bulk calculus as a source of carbon and nitrogen isotope data, however. It is not yet clear how much of an individual¿s life span dental cal…
miR-29b negatively regulates human osteoclastic cell differentiation and function: Implications for the treatment of multiple myeloma-related bone di…
2013
Skeletal homeostasis relies upon a fine tuning of osteoclast (OCLs)-mediated bone resorption and osteoblast (OBLs)-dependent bone formation. This balance is unsettled by multiple myeloma (MM) cells, which impair OBL function and stimulate OCLs to generate lytic lesions. Emerging experimental evidence is disclosing a key regulatory role of microRNAs (miRNAs) in the regulation of bone homeostasis suggesting the miRNA network as potential novel target for the treatment of MM-related bone disease. Here, we report that miR-29b expression decreases progressively during human OCL differentiation in vitro. We found that lentiviral transduction of miR-29b into OCLs, even in the presence of MM cells,…
Serum and urine markers of type I collagen metabolism in elderly women with high and low bone mineral density.
1996
The serum markers of bone formation (carboxy-terminal propeptide of type I collagen, PICP) and resorption (pyridinoline cross-links containing telopeptide of type I collagen, ICTP), as well as urinary resorption markers, pyridinoline (Pyr) and deoxypyridinoline (Dpyr), were studied in 78-year-old women with high (n = 18) and low (n = 17) bone mineral density (BMD) measured from the calcaneus and tibia. The low-BMD group had higher values for PICP (P = 0 center dot 025), Pyr (P = 0 center dot 001) and Dpyr (P < 0 center dot 001) than the high-BMD group. No inverse relationship between these markers and BMD was, however, observed within the study groups. ICTP, Pyr and Dpyr correlated with eac…
Silica as a morphogenetically active inorganic polymer.
2013
At present the scaffolds used for bioprinting of cells do not elicit morphogenetic responses in the cells. In the present study we approached a solution by studying the effect of an inorganic silica supplement added to an Na-alginate matrix. Bone- and osteoblast-like SaOS-2 cells were embedded into this organic polymeric matrix which was additionally enriched with 400 μM prehydrolyzed TEOS [tetra-ethoxy-silane], a source of ortho-silicate. In this silica-based matrix the cells synthesized hydroxyapatite crystallites after exposure to a mineralization activation cocktail composed of β-glycerophosphate, ascorbic acid and dexamethasone. The degree of hydroxyapatite synthesis, determined by sta…
Immunohistochemical Evaluation of Periodontal Regeneration Using a Porous Collagen Scaffold.
2021
(1) Aim: To immunohistochemically evaluate the effect of a volume-stable collagen scaffold (VCMX) on periodontal regeneration. (2) Methods: In eight beagle dogs, acute two-wall intrabony defects were treated with open flap debridement either with VCMX (test) or without (control). After 12 weeks, eight defects out of four animals were processed for paraffin histology and immunohistochemistry. (3) Results: All defects (four test + four control) revealed periodontal regeneration with cementum and bone formation. VCMX remnants were integrated in bone, periodontal ligament (PDL), and cementum. No differences in immunohistochemical labeling patterns were observed between test and control sites. N…
Metalloproteinase and TIMP expression by the human breast carcinoma cell line 8701-BC.
1993
It is widely accepted that collagenolytic enzymes are required to facilitate the invasion and spread of tumour cells into host tissues. Immunohistochemical, zymographic and PCR analyses have produced evidence that the recently established human mammary carcinoma cell line, 8701-BC, expresses several metalloproteinases (MMP-1, -2, -9 and -10) and their tissue inhibitors (TIMP-1 and -2). Application of these different techniques has led to several observations, both complementary and dissimilar. Whereas PCR analysis showed that mRNA was detected for each of the proteins, the immunolocalization study demonstrated that MMP-1, MMP-2, MMP-9 and TIMP-1 production was restricted to only a proportio…