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Biomedical subjects

V Woods

Publications and source records attributed to V Woods.

10 recordsLinked to original sources
PubMed1997

Role of melanoma growth stimulatory activity (MGSA/gro) on keratinocyte function in wound healing.

Melanoma growth stimulatory activity/gro alpha (MGSA), a member of the alpha-chemokine family, is produced by a variety of dermal and epidermal cells and can act in a paracrine and autocrine fashion. However, little is known about the importance of MGSA in wound healing. In this study, we quantified the levels of MGSA protein in burn blister and donor site wound fluids. We studied the effects of MGSA on proliferation and migration of primary human keratinocytes and modulation of their integrin expression. Blister fluids contained 0.79 ng/ml (range 0.018 to 4.86 ng/ml) MGSA. Substantial increasing amounts of MGSA were found in donor site fluids from day 1 through day 5 with mean levels ranging from 1.77 to 103 ng/ml at postoperative day 5, which correlated with increasing amounts of tumor necrosis factor alpha (r = 0.86), a known stimulus for MGSA production. In vitro proliferation experiments revealed a maximum stimulation (2.6-fold) with 10 ng/ ml MGSA for 7 days over unstimulated keratinocyte controls; the ED50 was 0.2 ng/ml. DNA content analysis revealed an increase in S phase with 10 ng/ml MGSA stimulation. In cultured keratinocytes, MGSA enhanced the mean fluorescence intensity for alpha 6, while no significant change was seen for beta 1, alpha 2 and alpha 5. We also studied the effect of topically applied MGSA (50 ng/cm2) on the healing of meshed split-thickness human skin grafts on athymic mice. In these wounds, MGSA stimulated the rate of epithelialization (P < 0.05) at day 7, and an increased proportion of mitotic keratinocytes was observed. Wound contraction was significantly (P < 0.05) reduced on days 7 and 14 in the MGSA-treated group. These results suggest that MGSA participates in wound healing by stimulating keratinocyte proliferation.

Animals↗
PubMed1996

Wound closure with human keratinocytes cultured on a polyurethane dressing overlaid on a cultured human dermal replacement.

BACKGROUND: Burn excision followed by immediate wound coverage has become the clinical standard for managing extensive burn injuries in much of the world. When sufficient autograft skin to achieve permanent wound closure is unavailable, cell culture technology has made the use of cultured human keratinocyte (HK) sheets clinically feasible. Whereas previous techniques have focused on development of multilayered, differentiated HK sheets, our attention has been drawn to using HK in a highly proliferative, less differentiated state. Time requirements for preparation of multistratified cultured HK are high, and preparatory steps may destroy important integrin adhesion molecules. METHODS: We describe the use of HK cultured to single layer confluence on a polyurethane membrane(HD), with serum-free medium. HK-HD grafts were transplanted to full-thickness wounds on athymic mice (n = 31). A second group of mice (DG-HK-HD), n = 28) received a living human dermal replacement containing cultured fibroblasts before placement of HK-HD. Control mice received HD alone (n = 4). Basement membrane proteins on healed wounds and surface integrins on cultured HK were identified by means of immunostaining and direct microscopic visualization. RESULTS: HK cultured just to the confluent state on polyurethane membrane were positive for integrins alpha(5) and alpha(6), major integrins on proliferating HK. Histologic analysis showed epithelialized wounds in all groups after 21 days. Using an anti-human involucrin antibody we demonstrated the presence of HK in 64.5% of the HK-HD group, 61% of the DG-HK-HD group, and 0% in the HD group. Mice that received the living human dermal replacement containing cultured fibroblasts in combination with HK-HD grafts developed a thick, well-vascularized neodermis. Strong laminin and collagen IV staining was observed in wound areas covered with HK. CONCLUSIONS: These data show that full-thickness wounds can be closed by application of a single layer of proliferating HK cultured on a biocompatible polyurethane membrane. This technique is an alternative to the use of multilayered, differentiated HK sheets. Preparation times for HK-HD grafts should be significantly shorter than required for multilayered HK sheets, technical efforts should be less, and more extensive wound areas could be covered.

Animals↗
PubMed1989

Platelet specific alloantigens on the platelet glycoprotein Ia/IIa complex.

The majority of platelet alloantigens are located on platelet glycoproteins IIb/IIIa. This report describes a codominant allelic system carried on the glycoprotein Ia/IIa complex, which we originally designated as Zava/Zavb but which is identical to the Bra/Brb system. Furthermore Zava was found to be identical to Hca. The alloantigens could not be detected using a direct binding enzyme immunoassay (EIA) with intact platelets, but were readily detected using a glycoprotein capture EIA and by radioimmunoprecipitation techniques. The two index cases (designated as homozygous Zava and Zavb) had alloantibodies against the corresponding antigen and did not react with their own platelets. Using these alloantibodies and a monoclonal antibody that reacts with the platelet glycoprotein Ia/IIa complex (12F1), we demonstrated that all Ia/IIa molecules carry either Zava or Zavb and we found that Zava and Zavb are on discrete populations of Ia/IIa. Following immunodepletion using either anti-Zava or anti-Zavb, all detectable Ia/IIa complexes from the respective homozygous platelets were removed. Immunodepletion of heterozygous Zava/Zavb with either anti-Zava or anti-Zavb did not reduce the amount of Ia/IIa complexes precipitable using the alternate alloantiserum. Population studies (n = 50) indicated the phenotypic frequency of Zava/Zava is less than 1%; Zava/Zavb is 18% and Zavb/Zavb is 82%. Four different alloantisera that had either anti-Zava or anti-Zavb reactivity also carried reactivity against the Baka or Bakb antigens which may suggest an association in the immune response to these alleles.

Adult↗
PubMed1987

In vitro differentiation of mouse embryonic yolk sac cells.

The embryonic yolk sac is the first site in the mammalian embryo in which cells are found that can carry out cell-mediated immune functions, yet the relation of cells of this primitive hematopoietic organ to the development of the mature immune system has not been established. We have initiated a series of experiments to determine the potential of cells of the mouse yolk sac to differentiate in vitro, in order to get an insight into the development of immunocompetence in this primary population of hematopoietic stem cells. The present paper describes the conditions promoting stem-cell differentiation and provides an initial characterization of cell surface phenotypes of the cell lineages established in vitro. Yolk sac cells obtained from 10- to 13-day mouse embryos were maintained in culture for more than 18 months, giving rise to a variety of cell types belonging to the hematopoietic lineages and culminating in the establishment of long-term cell lines. Supernatants of secondary mixed leukocyte cultures were found to be an effective source of growth factors promoting the initial differentiation as well as the maintenance of these cells. Flow-cytometric analysis showed that, in contrast to freshly obtained yolk sac cells, which had no detectable Thy 1 antigen, cells expressing significant levels of Thy 1 were obtained after 1 week or more of culture. Ly1 and Lyt 2 antigens were detected only rarely and the L3T4 (GK 1.5) antigen was never expressed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Discrimination between innate and cytophilic immunoglobulin on human peripheral blood lymphocytes: analysis by the direct antiglobulin rosette-forming reaction.

Bovine red blood cells linked to polyclonal or monoclonal anti-immunoglobulin antibodies are used in the direct antiglobulin rosetting reaction to detect surface-Ig on human lymphocytes. The sensitivity of this test is markedly increased by pretreating the red cells with trypsin. Enzyme-treated red cells, coupled to anti-human Fab or anti-light chain antibodies, react not only with innate Ig on B lymphocytes but also with smaller amounts of passively adsorbed, cytophilic Ig on up to 25% of freshly prepared peripheral blood (non-B) lymphocytes. In contrast, trypsinized red cells carrying anti-Ig isotype-specific antibodies react exclusively with B cell surface-Ig. Cytophilic Ig is abnormally firmly bound to lymphocytes separated on Ficoll-Hypaque at 20 degrees C or below, and is released very slowly during 3 h or more at 37 degrees C in vitro. Lymphocytes are free of detectable cytophilic Ig when isolated on Ficoll-Hypaque at 37 degrees C, and very little Ig is retained by non-B cells in suspensions purified on Percoll which, unlike Ficoll, does not increase Ig binding affinity. These lymphocyte separation procedures are recommended as a preliminary to B cell assays by sensitive antiglobulin techniques.

Agglutination↗
PubMed1976

Mutants of Saccharomyces cerevisiae resistant to the alpha mating-type factor.

Mutants that are resistant to alpha-factor have been isolated from a mating-type haploid strains of yeast by direct selection on agar medium containing partially purified alpha-factor. All resistant mutants isolated were found to be sterile. They were characterized and compared with mutants previously isolated as non-mating. Among 93 able to mate at low frequency and to sporulate, none showed linkage to the mating-type locus. The results support the hypothesis that the response to alpha-factor by cells of mating-type a is essential for mating.

Cell Differentiation↗
PubMedDate not supplied

Integrin and matrix molecule expression in cultured skin replacements.

Current tissue culture techniques enable human keratinocytes (HK) from a small section of skin to be grown into sheets of epithelium for treating extensive wounds. The additional use of dermal replacements coupled with cultured skin substitutes may improve handling properties and effect ultimate healing results. Adhesion of cultured HK grafts to wounds, and final success rates of HK grafting, are variable and frequently unsatisfactory. To evaluate adhesion molecule (integrin) expression by cultured grafts, as well as matrix molecule distribution, we performed immunohistologic analysis of integrin expression on HK cultured on plastic and a polyurethane membrane, as well as on two dermal substitutes. Multilayered HK sheet grafts were prepared by culturing cells in plastic tissue culture dishes, and HK were cultured to single-layer confluence on polyurethane membranes (Hydroderm; Wilshire Medical Inc., Dallas, Texas). Composite grafts were prepared by seeding proliferating HK on Dermagraft, composed of human neonatal fibroblasts cultured in polyglactin mesh (Advanced Tissue Sciences, La Jolla, Calif.) and on AlloDerm, an acellular human dermis (LifeCell Inc., The Woodlands, Texas). Immunohistologic staining was performed for the integrin subunits alpha 5, alpha 6, and alpha v. Staining for matrix molecules included fibronectin, laminin-1, and laminin-5. HK in cultured epithelial sheets showed integrin alpha 6 expression on basal cells, and only faint alpha 5 and alpha v staining. HK cultured to confluence on Hydroderm reacted with monoclonal antibodies specific for alpha 5, alpha 6, and alpha v. Through HK adhered well to Dermagraft, there was reduced adhesion of HK on AlloDerm that was not accelerated by addition of fibronectin. HK in composite grafts showed distinct reactivity according to the time in culture. HK on Dermagraft lost alpha 5 reactivity by day 17 and only weak alpha v reactivity was seen. Basal keratinocytes on AlloDerm, however, remained alpha 5 and alpha v positive. In both composite grafts, integrin alpha 6 expression was limited to basal keratinocytes.

Biocompatible Materials↗