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Biomedical subjects

M D Mayes

Publications and source records attributed to M D Mayes.

41 records · Page 3Linked to original sources

The mineralization of elastic fibers and alterations of extracellular matrix in pseudoxanthoma elasticum. Ultrastructure, immunocytochemistry, and X-ray analysis.

Histologic paraffin sections of pseudoxanthoma elasticum (PXE)-involved skin of forearm and axilla were used for histochemistry and immunohistochemical and analytical electron microscopy to study the progressive mineralization in the dermis of patients with PXE. The von Kossa technique identified mineral deposits throughout the reticular PXE dermis. X-ray analysis revealed patterns of calcium and phosphorus deposition in the von Kossa-positive areas, and the immunohistochemical staining using monoclonal antibodies identified increased chondroitin-6-sulfate in these areas when compared with normal skin. Scanning transmission electron microscopy observation combined with X-ray dot mapping show calcium and phosphorus to be codistributed within the mineralized area. This study confirms by new methods the increase in chondroitin-6-sulfate, alterations in elastin and collagen, and a high calcium and phosphorus elemental distribution matching the mineralized area in the PXE dermis.

Calcium↗

The characterization of normal and scleroderma skin fibroblasts cultured in a collagen gel matrix.

Fibroblasts from normal and progressive systemic sclerosis involved skin more closely resemble in vivo cells when cultured in a collagen gel matrix, than do fibroblasts cultured on plastic. Ultrastructural studies show that the cytoskeleton and secretory organelles from these cells are better developed in the presence of a collagen gel. Fibronectin, glycosaminoglycans and collagen fibrils are produced by the cells and deposited in the preformed matrix. Collagen synthesis is greater in the scleroderma derived fibroblasts for all culture conditions with increased deposition in the matrix. Total collagen production form cells associated with the gel is less than that from those cultured on plastic, suggesting an inhibition of collagen synthesis by the preformed collagen matrix.

Cells, Cultured↗

Increased dermal elastic fibers in the tight skin mouse.

OBJECTIVE: The tight skin (Tsk-1) mouse has been proposed as a model for systemic sclerosis on the basis of increased accumulation of collagen and glycosaminoglycans in the skin, and by the presence of serum autoantibodies. The genetic basis of the mutation has been identified as a genomic duplication within the fibrillin-1 (Fbn-1) gene that results in a larger than normal Fbn-1 transcript, but the mechanism that leads to dermal fibrosis is unclear Fibrillin molecules associate into a polymer that is coated with elastin molecules to form elastic fibers. To further evaluate the Tsk-1 mouse model of scleroderma, we have studied elastic fibers in the skin of these mice. METHODS: Skin sections obtained from C57BL/6-TSK+ (Tsk-1) and C57BL6-pa/+ (control) mice were stained with Masson's trichrome for evaluation of collagen and Gomori's aldehyde fuchsin stain for elastic tissue. Computer assisted image analysis was performed to quantify differences in histologic sections. RESULTS: Tsk-1 mice had a highly significant increase in the percentage of elastic fibers (19.6%) in the dermis compared to control mice (7.9%) [p < 0.001]. This correlates with the findings in the skin of systemic sclerosis patients where increased elastic fibers have been observed. In addition, an increased level of dermal collagen staining was also observed in the Tsk-1 dermis (82.9%) compared with the level in normal sections (73.7%) [p < 0.01]. CONCLUSION: These data support the use of the Tsk-1 mouse as a model for the connective tissue abnormalities of human scleroderma.

Animals↗