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W Press

Publications and source records attributed to W Press.

15 recordsLinked to original sources
PubMed1995

Transforming growth factor alpha gene expression in cultured human keratinocytes is unaffected by cellular aging.

BACKGROUND: Cultured human keratinocyte grafts have been shown to stimulate endogenous reepithelialization of both chronic nonhealing and acute partial-thickness wounds. This effect is most likely mediated by cytokines that stimulate keratinocyte growth, such as transforming growth factor alpha. The effect of cellular age on cytokine expression by cultured grafts used for this purpose is presently undefined. In this study, transforming growth factor alpha gene expression in cultured foreskin keratinocytes from donors varying in age from 2 to 82 years was analyzed semiquantitatively by two separate methods, ie, Northern hybridization and competitive polymerase chain reaction. RESULTS: No pattern of decline in transforming growth factor alpha messenger RNA expression with increasing cellular age was observed by either analysis. CONCLUSION: The results indicate that expression of transforming growth factor alpha by cultured grafts may not be significantly affected by increasing cellular age and suggest that, even in the elderly, cultured autografts may be effective as pharmacologic agents for wound treatment.

Adult↗
PubMed1995

The generation of anchoring fibrils by epidermal keratinocytes: a quantitative long-term study.

Anchoring fibrils (AFs) are derived from basal keratinocytes, but the kinetics of their formation is unknown. In this study, de novo generation of AFs by cultured human keratinocyte autografts was assessed from 1 week to 6 years postgrafting. Within 2 weeks, AF population densities were equal to those of normal controls and remained normal thereafter. However, AF diameters were narrow compared to controls (P < 0.05) until 3 years postgrafting. The depth of extension of AF-anchoring plaque lattices into the subjacent stroma was normal by 3 weeks but, after 1 month, was typically 1.5-to 2-fold greater than normal. The findings indicate that: (1) basal keratinocytes immediately re-establish a full complement of AFs; (2) once reformed, AF populations remain normal in density over time; (3) nascent AFs are thin and require several years to reach full maturity; and (4) abnormally thick AF lattices may form over time in healed wounds.

Basement Membrane↗
PubMed1987

A large-scale, orthogonal network of microfibril bundles in the corneal stroma.

Orthogonal and parallel arrays of microfibril bundles are described in the corneal stroma of embryonic and adult chickens. The arrays lie parallel to the corneal surface and are distributed in the extracellular matrix between Bowman's layer and Descemet's membrane. The individual microfibril bundles measure 0.1-0.25 micron in diameter and consist of 20-30 "tubular" rods, of approximately 15 nm diameter, and an apparently structureless matrix. The arrays have a spacing of approximately 3 microns. We speculate that the microfibril bundles serve as a scaffolding for the corneal stroma or as a light-diffracting element. With some variations in distribution and organization, the arrays of microfibril bundles also occur in calf, rabbit, rat, newborn mice, toad, and goldfish, but not in adult human corneas.

Aged↗
PubMed1986

Type VI collagen in extracellular, 100-nm periodic filaments and fibrils: identification by immunoelectron microscopy.

Filaments and fibrils that exhibit a 100-nm axial periodicity and occur in the medium and in the deposited extracellular matrix of chicken embryo and human fibroblast cultures have been tentatively identified with type VI collagen on the basis of their similar structural characteristics (Bruns, R. R., 1984, J. Ultrastruct. Res., 89:136-145). Using indirect immunoelectron microscopy and specific monoclonal and polyclonal antibodies, we now report their positive identification with collagen VI and their distribution in fibroblast cultures and in tendon. Primary human foreskin fibroblast cultures, labeled with anti-type VI antibody and studied by fluorescence microscopy, showed a progressive increase in labeling and changes in distribution with time up to 8 d in culture. With immunoelectron microscopy and monoclonal antibodies to human type VI collagen followed by goat anti-mouse IgG coupled to colloidal gold, they showed in thin sections specific 100-nm periodic labeling on extracellular filaments and fibrils: one monoclonal antibody (3C4) attached to the band region and another (4B10) to the interband region of the filaments and fibrils. Rabbit antiserum to type VI collagen also localized on the band region, but the staining was less well defined. Control experiments with antibodies to fibronectin and to procollagen types I and III labeled other filaments and fibrils, but not those with a 100-nm period. Heavy metal-stained fibrils with the same periodic and structural characteristics also have been found in both adult rat tail tendon and embryonic chicken tendon subjected to prolonged incubation in culture medium or treatment with adenosine 5'-triphosphate at pH 4.6. We conclude that the 100-nm periodic filaments and fibrils represent the native aggregate form of type VI collagen. It is likely that banded fibrils of the same periodicity and appearance, reported by many observers over the years in a wide range of normal and pathological tissues, are at least in part, type VI collagen.

Adenosine Triphosphate↗
PubMedDate not supplied

Acceleration of skin regeneration from cultured epithelial autografts by transplantation to homograft dermis.

Cultured epithelial autografts transplanted to homograft dermis were analyzed histopathologically from 9 days to 2.25 years after grafting and compared with cultured epithelial autografts transplanted to wound beds devoid of homograft dermis in the same patient. The results suggested that grafting to a dermal substrate accelerates biologic events in skin regeneration from cultured epithelial autografts. Both rete ridge development and normalization of the epidermal keratin program from a "hyperproliferative" to a normal pattern occurred months sooner in the cultured epithelial autografts placed on a dermal matrix. Regeneration of anchoring fibrils was also accelerated. Neither repopulation by Langerhans cells nor repigmentation appeared to be altered significantly by grafting to dermal tissue. By special stain, the elastin network of the allograft dermis could still be visualized at 2.25 years, indicating long-term persistence of the homograft matrix. By clinical assessment the rate of successful engraftment ("take rate") of cultured epithelial autografts grafted to allodermis was estimated to be about 95%, and long-term durability was excellent.

Adult↗