Linked Life Data

2968758

Source:http://linkedlifedata.com/resource/pubmed/id/2968758

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1988-8-11
pubmed:abstractText
Basement membranes were divided into two types: 1) thin basement membranes, such as those of the epidermis, trachea, jejunum, seminiferous tubule, and vas deferens of the rat, the ciliary process of the mouse, and the seminiferous tubule of the monkey, and 2) thick basement membranes, such as the lens capsule of the mouse and Reichert's membrane of the rat. High-magnification electron microscopy was used to examine both types after fixation either in glutaraldehyde followed by postosmication or in potassium permanganate. The basic structure of thin and thick basement membranes was found to be a three-dimensional network of irregular, fuzzy strands referred to as "cords"; the diameter of these cords was variable, but averaged 4 nm in all cases examined. The spaces separating the cords differed, however. In the lamina densa of thin basement membranes, the diameter of these spaces averaged about 14 nm in every case, whereas in the lamina lucida it ranged up to more than 40 nm. Intermediate values were recorded in thick basement membranes. Finally, the third, inconstant layer of thin basement membranes, pars fibroreticularis, was composed of discontinuous elements bound to the lamina densa: i.e., anchoring fibrils, microfibrils, or collagen fibrils. In particular, collagen fibrils were often surrounded by processes continuous with the lamina densa and likewise composed of a typical cord network. Finally, two features were encountered in every basement membrane: 1) a few cords were in continuity with a 1.4- to 3.2-nm thick filament or showed such a filament within them; the filaments became numerous after treatment of the seminiferous tubule basement membrane with the proteolytic enzyme, plasmin, since cords decreased in thickness and could be reduced to a filament, and 2) at the cord surface, it was occasionally possible to see 4.5-nm-wide sets of two parallel lines, referred to as "double tracks." On the basis of evidence that the filaments are type IV collagen molecules and the double tracks are polymerized heparan sulfate proteoglycan, it is proposed that cords are composed of an axial filament of type IV collagen to which are associated glycoprotein components (laminin, entactin, fibronectin) and the double tracks of the proteoglycan.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0002-9106
pubmed:author
pubmed:issnType
Print
pubmed:volume
181
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
341-58
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Three-dimensional network of cords: the main component of basement membranes.
pubmed:affiliation
Department of Anatomy, McGill University, Montreal, Quebec, Canada.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't