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Biomedical subjects

D E Peters

Publications and source records attributed to D E Peters.

7 recordsLinked to original sources
PubMed1989

Collagen organization in mandrel-grown vascular grafts.

The organization of collagen in custom-built biosynthetic vascular prostheses (Omniflow Vascular Graft), which are suitable for peripheral revascularization, has been examined. The grafts were a glutaraldehyde-tanned ovine-collagen composite with a polymer mesh reinforcement. Comparisons were made between grafts using different mesh fiber polymers and knit patterns. There was a basic similarity in the arrangement of the tissue structure in all graft types. Scanning electron microscopy and light microscopy showed that the collagen formed a layered structure which fully encased the polymer mesh and held it firmly in position. Rather than polymer mesh, the inner surface of the graft was found to be collagen, and lined with a layer of flattened cells. Collagen formed a continuous layer surrounding the mesh, with no distinct boundary, membrane or structurally weak point being apparent. Immunohistology, using a monoclonal antibody specific for type III collagen, and chemical analysis, indicated that there was high proportion of type III collagen in the grafts, particularly in the region surrounding the mesh fibers.

Animals↗
PubMed1989

Development of monoclonal antibodies to collagens for assessing host-implant interactions.

The biologic response to surgical implants is of importance in understanding the host interactions relating to long-term patency of implants. The methodology currently available for the assessment of host-biomaterial interactions is subjective and is limited to identification of inflammatory responses and general histopathological staining procedures associated with these processes. A clearer appraisal of the nature and type of extracellular matrix components related to the host response to the implanted biomaterials would assist in the development of biomaterials and would allow an earlier means of predicting biocompatibility. The extracellular matrix consists of a range of similar collagen types which are difficult to distinguish using polyclonal antibodies. However, with the advent of hybridoma technology, monoclonal antibodies with the desired specificities can be produced to provide very powerful probes for assessing host-implant interactions. There were several problems associated with the production of these antibodies, mainly arising from collagens being extremely poor immunogens. The present study has examined these problems and has demonstrated that monoclonal antibodies against a range of collagen types can be produced. These antibodies were all highly specific for collagen type, but for a given collagen type, antibodies with different species specificities could be obtained. These antibodies were shown to be suitable for immunohistology of various connective tissue samples and were used to examine collagen-based vascular prostheses (Omniflow Vascular Graft) after retrieval from canine models. These data demonstrated that the monoclonal antibodies to collagens were excellent for the analysis of surgical implants and biomaterials after retrieval.

Animals↗
PubMed1985

A morphologic study of a mild form of ovine dermatosparaxis.

A mild form of dermatosparaxis has recently been identified in sheep from several properties in central Victoria. Examination of the skin of affected animals by both transmission and scanning electron microscopy has shown that the structure of the majority of the collagen fibrils is irregular and the distorted fibrils do not pack into tight and well-ordered fiber bundles. Examination of the skin by light microscopy has shown that the fiber bundles are not compact and interwoven, and that there is a tendency for the collagen to form layered sheets in the reticular dermis. These studies also show that there is no buildup in the elastic tissue component, but that there is an increased population of fibroblasts in the affected animals.

Animals↗
PubMed1976

The chemical composition of wool. XV. The cell membrane couplex.

The cell membrane complex of wool has been examined by electron microscopy of stained cross sections after immersion of the wool in formic acid. The cell membrane complex of the cortex is considerably modified by the treatment, but that of the cuticle appears unchanged. Resistant membranes from cuticle cells, cortical cells and wool have been prepared by treatment with performic acid-ammonia. Amino acid analyses show that the resistant membranes from the cuticle contain citrulline but those from cortical cells do not. It is concluded that the cell membrane complex of the cuticle differs from that of the cortex. Because of the high lysine content of the resistant membranes, their resistance to chemical attack, the hydrophobicity of epicuticle and the observation of a small amount of epsilon-(gamma-glutamyl)lysine, it is postulated that the resistant membranes may contain an appreciable amount of epsilon-(gamma-glutamyl)lysine cross links.

Amino Acids↗
PubMed1975

Study by PMR spectroscopy and gel chromatography of the unfolding of substituted kerateines in 8 M urea.

Various S-substituted derivatives of the reduced low sulphur and high proteins from wool have been prepared in which the substituted group is hydrogen, carboxymethyl, carboxethyl, methyl, carbamidomethyl, cyanoethyl and aminoethyl. The proton magnetic resonance (PMR) spectra and gel filtration chromatography of these proteins have been examined in 8 M urea solution as a function of pH in order to determine conditions under which the proteins occur as random coils in solution with no evidence for the occurrence of non-covalent interactions. The PMR method described in an earlier paper (1) provides an easier and much more sensitive method for the observation of non-covalent interactions in random coil proteins than does the measurement of elution volumes in gel chromatography. The results obtained by both methods are consistent and show that the widest range of pH for which unfolding occurs in 8 M urea is obtained with the S-carboxymethyl, S-carboxyethyl, S-methyl and S-carbamidomethyl derivatives.

Amino Acids↗