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Collagen Layer (collagen + layer)

Distribution by Scientific Domains
Medical Sciences80%

Selected Abstracts

A New Biological Matrix for Septal Occlusion

JOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 2 2003
CHRISTIAN JUX, M.D.
The ideal septal occluder scaffold should promote the healthiest and most complete healing response possible while eventually facilitating the full resorption of the material, leaving "native" tissue behind. An excellent biocompatibility of the scaffold tissue is a prerequisite for quick, complete, and firm ingrowth of the device, optimizing outcomes and minimizing the potential for complications. Intestinal collagen layer (ICL) is a highly purified (acellular) bioengineered type-1 collagen derived from porcine submucosa. It is gradually resorbed by the host organism and subsequently replaced by the host tissue. CardioSEAL® occluders were modified by substituting the conventional polyester fabric for an intestinal collagen layer (ICL). Percutaneous transcatheter closure of interventionally created atrial septal defects was performed in lambs using these modified occluders. A complete pathomorphological investigation including histology was carried out after 2, 4, and 12 weeks follow-up. Standard CardioSEAL implants served as a control group. After 2 weeks in vivo the devices were already covered completely by neo-endothelium. Compared with the conventional synthetic scaffold, ICL devices showed a quicker endothelialization, decreased thrombogenicity, and superior biocompatibility with no significant cellular infiltration observed in the histology of explants with ICL fabrics. After 3 months in vivo the collagen layer remained mechanically intact, but began to show the first histological signs of mild disintegration, gradual resorption, and remodeling. In conclusion, short-term results from preliminary in vivo experiments using a bioengineered collagen matrix as the occluder tissue scaffold showed excellent biocompatibility. This resulted in superior overall results: quicker endothelialization, a decreased thrombogenicity, and decreased immunological host response. (J Interven Cardiol 2003;16:149,152) [source]

Collagenous colitis and eosinophilic gastritis in a 4-year old girl: a case report and review of the literature

ACTA PAEDIATRICA, Issue 9 2007
Eric I Benchimol
Abstract Collagenous colitis (CC), a form of microscopic colitis, is characterized by a thick subepithelial collagen layer in the colon in the presence of chronic nonbloody watery diarrhoea and macroscopically normal-appearing colonic mucosa. Typically affecting elderly adults, CC is rare in children with only 12 cases previously reported in the literature. We report the case of a 4-year-old girl with CC associated with eosinophilic gastritis, which was clinically responsive to treatment with ketotifen, a benzocycloheptathiophene derivative, and H1 class of antihistamine that stabilizes mast cells and potentially impairs eosinophil migration to target organs. We review the published cases of paediatric-onset CC and summarize the links between eosinophils and CC in the clinical and basic science literature. Conclusion: CC is a rare cause of chronic diarrhoea in children and may relate to mast cell and eosinophil activity. [source]

Light and Electron Microscopy of the Spore of Myxobolus heckelii n. sp. (Myxozoa), Parasite from the Brazilian Fish Centromochlus heckelii (Teleostei, Auchenipteridae)

THE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 6 2009
CARLOS AZEVEDO
ABSTRACT. A myxosporean parasitizing the gill filaments of the freshwater teleost fish Centromochlus heckelii collected in the Tocantins River (Lower Amazonian Region, Brazil) is described using light and electron microscopy. This parasite produces spherical to ellipsoidal cyst-like plasmodia up to 250 ,m in diameter, with a thick wall strengthened by several stratified juxtaposed crossed collagen layers, whose thickness varies according to the number of the layers. Several compressed fibroblasts are observed among the collagen fibrils. Deposits of spherical dense material are scattered at the internal periphery of the cysts. Plasmodia and different developmental stages, including immature and mature spores, filled the central region of the cysts. The spore body is ellipsoidal in valvar view and biconvex in sutural view. It is formed by two equal-sized and symmetric valves measuring 12.7 ,m long (12.2,13.1) (n=50), 6.6 ,m wide (6.3,6.9) (n=25), and 4.0 ,m (3.7,4.4) (n=20) thick. A thin layer formed by fine and anastomosed microfibrils is observed at the spore surface. Two equal, elongated pyriform polar capsules measure 2.9 ,m (2.7,3.3) × 1.7 ,m (1.4,2.0) (n=25), each containing four or five oblique polar filament coils. The binucleated sporoplasm contains numerous spherical sporoplasmosomes, glycogen particles, and a large vacuole with fine granular matrix. Based on the morphological and ultrastructural differences and specificity of the host, we describe this isolate as a new myxosporidian, Myxobolus heckelii n. sp. (Myxozoa, Myxosporea). [source]

Light and Electron Microscopic Analyses of Autologous Pericardial Tissue Used as a Small-Diameter Arterial Graft in Dogs

ARTIFICIAL ORGANS, Issue 1 2002
Won Gon Kim
Abstract: As a form of small-diameter arterial graft, we implanted fresh autologous pericardium and pericardium treated with 0.6% glutaraldehyde in the bilateral carotid arteries of dogs and then compared the time-related changes of the grafts explanted after the predetermined periods. The pericardial grafts were implanted in 1 animal each for scheduled periods of 3 days, 2 weeks, 1 month, 3 months, and 6 months. The retrieved grafts were processed for light and electron microscopic analyses following gross observation. The glutaraldehyde-treated small-diameter pericardial vascular grafts showed a better endothelialization of the blood-contacting surface and a slower fragmentation of the collagen layers than the fresh grafts although it has yet to be proven whether these differences are so significant as to affect the patency results between the groups. [source]