Search results for "collage"
showing 10 items of 638 documents
Priming with proangiogenic growth factors and endothelial progenitor cells improves revascularization in linear diabetic wounds
2014
In the present study, we investigated whether proangiogenic growth factors and endothelial progenitor cells (EPCs) induce favourable effects on cutaneous incisional wound healing in diabetic mice. The proangiogenic effects of human EPCs were initially analyzed using a HUVEC in vitro angiogenesis assay and an in vivo Matrigel assay in nude mice (n=12). For the diabetic wound model, 48 Balb/c mice with streptozotocin (STZ)-induced diabetes were divided randomly into 4 groups (12 mice in each group). Subsequently, 3, 5 and 7 days before a 15-mm full-thickness incisional skin wound was set, group 1 was pre-treated subcutaneously with a mixture of vascular endothelial growth factor (VEGF)/basic …
Collagens in the injured porcine intervertebral disc
1994
Spinal pain often is thought to be due to degeneration and mechanical failure of the intervertebral disc. Since the mechanical strength of the tissue depends on collagen fibers, the present study was designed to investigate the reactions in collagen metabolism after an experimentally induced disc injury. Five domestic pigs underwent an incision in the anterior part of the annulus fibrosus of disc L4-L5 through a retroperitoneal approach. The animals were killed 3 months postoperatively, and the injured discs and intact discs (controls) from different animals were removed for chemical analysis. Slices were cut from seven different parts across the disc. The concentration of total collagen (h…
Heart valve tissue engineering: how far is the bedside from the bench?
2015
Heart disease, including valve pathologies, is the leading cause of death worldwide. Despite the progress made thanks to improving transplantation techniques, a perfect valve substitute has not yet been developed: once a diseased valve is replaced with current technologies, the newly implanted valve still needs to be changed some time in the future. This situation is particularly dramatic in the case of children and young adults, because of the necessity of valve growth during the patient's life. Our review focuses on the current status of heart valve (HV) therapy and the challenges that must be solved in the development of new approaches based on tissue engineering. Scientists and physicia…
Constitutive modeling of ascending thoracic aortic aneurysms using microstructural parameters.
2016
Ascending thoracic aortic aneurysm (ATAA) has been associated with diminished biomechanical strength and disruption in the collagen fiber microarchitecture. Additionally, the congenital bicuspid aortic valve (BAV) leads to a distinct extracellular matrix structure that may be related to ATAA development at an earlier age than degenerative aneurysms arising in patients with the morphological normal tricuspid aortic valve (TAV). The purpose of this study was to model the fiber-reinforced mechanical response of ATAA specimens from patients with either BAV or TAV. This was achieved by combining image-analysis derived parameters of collagen fiber dispersion and alignment with tensile testing dat…
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…
Glomerular basement membrane: evidence for collagenous domain of the alpha 3 and alpha 4 chains of collagen IV.
1990
Abstract A collagenous component(s) of Mr = 60K was extracted from glomerular basement membrane with urea and was purified. Upon digestion, it yielded a collagenase-resistant fragment(s) of Mr = 23.5K. Both component and fragment showed immunochemical identity with the noncollagenous domains of the new α3 & α4 chains of collagen IV. The component is characterized by a collagenous domain of about 280 residues and a noncollagenous domain of about 250 residues. These findings further establish these new chains as distinct entities of collagen IV.
Antiglomerular basement membrane antibodies in human sera: Detection by a modified micro-ELISA
1985
An enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to human glomerular basement membrane has been developed. Special emphasis has been put on the choice of microtiter plates which were coated with a collagenase digest of human glomerular basement membrane. Results differed markedly between the different microtiter plates. Best results were obtained with a flexible polyvinylchloride microtiter plate with flat wells (Dynatec). This plate exhibited the highest positive/negative ratio and the lowest intraassay standard deviation. Optimal conditions for each step in the ELISA have been determined. The assay proved to be specific, sensitive, and reproducible. Circulating ant…
On the search of the ideal barrier membrane for guided bone regeneration
2018
Background GBRs are essential procedures in implant dentistry and periodontology where barrier membranes play an important role by isolating soft tissue and allowing bone to grow. Not all membranes function the same way, as they differ from their origin and structure, it is important to understand how membranes behave and differ one from others in order to achieve a predictable treatment. Material and methods A systematic search on Medline by two independent reviewers was performed for articles published until July 2017 reporting the characteristics or properties of barrier membranes. The question that preceded the search was designed according to PICO rules. Results A total of 124 articles…
Long-term follow-up results of vesico-ureteral reflux treated with subureteral collagen injection (SCIN).
2000
Endoscopic sub-ureteral injection is at the present a widely used technique for the treatment of vesico-ureteral reflux and it has a good range of efficacy, from 50% up to 90% in relation to different grades. In this paper we report our 1-7 year follow-up results of sub-ureteral collagen injection (SCIN).Between 1991 and 1997 we treated with SCIN 129 refluxing ureters in 93 children (60 females and 32 males), mean age 2.1 years (range 3 months-5 years). Fifty-five children had monolateral, but 37 had bilateral reflux. Distribution among different grades was 42 ureters (32.5%) grade 2, 63 (48.8%) grade 3, 24 (18.6%) grade 4. Children were treated with injection of highly purified bovine coll…