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Biomedical subjects

R L Trelstad

Publications and source records attributed to R L Trelstad.

At least 91 records · Page 5Linked to original sources
PubMed1977

Patterns of high tension electrical injury in children and adolescents and their management.

High tension electrical burn injury occurred in twenty-nine patients over a period of seven years, causing two deaths, and demonstrating two reasonably distinct patterns. Major surface thermal burns from involvement in an electric arc, augmented by flame burns of ignited clothing, occurred in eleven patients. By contrast, eighteen children demonstrated wounds of entrance and exit of current and varying effects of deep thermal injury along the path of the maximally conductive blood vessels and nerves of extremities. An aggressive surgical approach was taken in patients with both types of injury, with the objective of prompt identification and excision of devitalized tissues and closure of thw wound. In the deep condictuve type of injury, frozen section and subsequent histologic study served as a guide to adequacy of excision and preservation of viable tissue. Even so, amputation of fifteen extremities and four other major excisions were required in twelve patients.

Adolescent↗
PubMed1977

Osteogenesis imperfecta congenita: evidence for a generalized molecular disorder of collagen.

Collagen from bone (femur and calvarium), rib cartilage, skin, tendon, sclera, and cornea has been isolated and purified from a deceased 4-day-old infant with osteogenesis imperfecta congenita. Amino acid analysis indicated that the content of hydroxylysine was doubled in bone collagen and increased by 55% in that of cartilage as compared with age-matched normal tissues. The levels of covalently bound glucose and galactose were proportionately increased in both collagens. Collagen purified from other tissues revealed smaller increases in lysyl hydroxylation. These data suggest that at least one form of osteogenesis imperfecta congenita is associated with a molecular alteration of collagen involving hydroxy-lysine and that this alteration is particualrly marked in collagens obtained from calcifying tissues.

Amino Acids↗
PubMed1976

Collagen fibrillogenesis: intermediate aggregates and suprafibrillar order.

Polymerization of collagen in vitro has been studied with the electron microscope at early time points of fibril assembly. We have found morphologically distinct stages of aggregation, which we suggest represent successive steps in fibril formation. Linear growth of the fibril appears to occur by the tandem addition of aggregates to each other and subsequently to the ends of a subfibril; lateral growth occurs by the entwining, like a rope, of these subfibrils. Fibrillogenesis is also accompanied by extensive development of suprafibrillar order in which various patterns of parallel, spiral, and orthogonal sets of fibrils were frequently observed.

Animals↗
PubMed1976

Vitreous body collagen. Evidence for a dual origin from the neural retina and hyalocytes.

Two different cells types have been shown to synthesize embryonic chick vitreous collagen (vitrosin) at different stages of development. Identification of vitrosin was established by labeling the embryos in ovo [3H]proline at stages 23 and 28 and separating the extracted vitreous collagen alpha-chains by carboxymethylcellulose chromatography. The labeled collagen consisted predominately of alpha 1 chains, indicating a molecule in the form of a trimer of identical chains designated (alpha 1)3. The molecular weight of the labeled chains measured approximately 95,000 daltons by molecular sieve chromatography, and contained 41% of their imino acid as 4-hydroxyproline. To establish which eye tissues synthesize vitrosine, the collagens produced in organ culture by the isolated neural retina, lens and vitreous body from stages 26-27, 29-30, and 40 were examined. At the two earlier stages, only the neural retina synthesized large quantities of (alpha 1)3 collagen whereas the lens and the cells within the vitreous body itself synthesized relatively small amounts of collagen characterized by an alpha 1:alpha 2 ratio of about 2:1. At stage 40, however, the cells of the vitreous body itself synthesized the greatest quantities of collagen, which now was predominantly an (alpha 1)3 type molecule. Stage 40 neural retina and lens synthesized lesser amounts of collagen with an alpha 1:alpha 2 ratio of 2 to 3:1. Chick vitrosin thus appears to be synthesized by the neural retina in early embryonic stages, whereas the major contribution derives from cells within the vitreous body in later development.

Animals↗
PubMed1974

Epithelial collagens and glycosaminoglycans in the embryonic cornea. Macromolecular order and morphogenesis in the basement membrane.

The embryonic corneal epithelium synthesizes both collagen and chondroitin sulfate and excretes them across the basement membrane into the subepithelial space where they assemble into a spiraling orthogonal matrix of fibrils. The assembly of collagen into fibrils is first apparent at the outer face of the basement membrane in a region of ordered chondroitin sulfate molecules. Hyaluronate, another morphogenetically important corneal macromolecule, is produced at these early stages only by the inner endothelium. These correlated biosynthetic and ultrastructural data demonstrate discrete macromolecular products of the two corneal epithelia with differing morphogenetic properties and functions.

Animals↗
PubMed1973

Cartilage collagen: a staggered substructure in reconstituted fibrils.

In contrast to the typical transverse banding pattern of native and reconstituted skin collagen fibrils, reconstituted fibrils of cartilage collagen have an oblique banding pattern that results from a regular axial shift (89 angstroms) of component "subfibrils." The 89-angstrom shift may be related to the major helix of the collagen molecule.

Animals↗