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Biomedical subjects

P V Long

Publications and source records attributed to P V Long.

8 recordsLinked to original sources
PubMed1992

Stimulation of human prostatic carcinoma tumor growth in athymic mice and control of migration in culture by extracellular matrix.

The tumorigenicity, migration, growth and invasiveness of certain tumor cells is stimulated by basement membranes. Here we have examined the effect of Matrigel, an extract of basement membrane proteins, on the behavior of several prostate cancer cell lines, testing their growth and invasiveness in vitro and in vivo. Cells of the Tsu-prI line were more invasive than PC-3, Du-145, or LNCaP cells. Peptide inhibitors implicated laminin in the migration and invasion of these cells. When these cells were suspended in Matrigel and injected into nude mice, their growth was greatly enhanced, since large tumors formed in athymic nude mice whereas virtually no tumors were observed in the absence of Matrigel. The growth of a slowly growing line, LNCaP, was increased by exogenous basic fibroblast growth factor when injected with Matrigel. A laminin cell adhesion peptide, YIGSR, was a potent inhibitor of Matrigel-stimulated tumor growth implicating cell-laminin interactions in this process. These results suggest that tumor growth of prostate adenocarcinoma cells may be dependent both on cellular growth factors and on cell-matrix interactions mediated by laminin which facilitate the development of transplanted tumors in nude mice.

Animals↗
PubMed1992

A simple, quantitative method for assessing angiogenesis and antiangiogenic agents using reconstituted basement membrane, heparin, and fibroblast growth factor.

BACKGROUND: Blood vessel growth is necessary for normal tissue homeostatis and contributes to solid tumor growth. Methods to quantitate neovascularization should be useful in testing biological factors and drugs that regulate angiogenesis or to induce a vascular supply to promote wound healing. EXPERIMENTAL DESIGN: An extract of basement membrane proteins (Matrigel) was found to reconstitute into a gel when injected subcutaneously into C57/BL mice and to support an intense vascular response when supplemented with angiogenic factors. RESULTS: New vessels and von Willebrand factor antigen staining were apparent in the gel 2-3 days after injection, reaching a maximum after 3-5 days. Hemoglobin content of the gels was found to parallel the increase in vessels in the gel allowing ready quantitation. Angiogenesis was obtained with both acidic and basic fibroblast growth factors and was enhanced by heparin. Several substances were tested for angiostatic activity in this assay by coinjection in Matrigel with fibroblast growth factor and heparin. Platelet-derived growth factor BB, interleukin 1-beta, interleukin-6, and transforming growth factor-beta were potent inhibitors of neovascularization induced by fibroblast growth factor. Tumor necrosis factor-alpha did not alter the response but was alone a potent inducer of neovascularization when coinjected with Matrigel and heparin. Consistent with the previously demonstrated importance of collagenase in mediating endothelial cell invasion, a tissue inhibitor of metalloproteinases that also inhibits collagenases was found to be a potent inhibitor of fibroblast growth factor-induced angiogenesis. CONCLUSIONS: Our assay allows the ready quantitative assessment of angiogenic and anti-angiogenic factors and should be useful in the isolation of endothelial cells from the capillaries that penetrate into the gel.

Angiogenesis Inducing Agents↗
PubMed1985

Epicutaneous induction of tolerance with acrylates and related compounds.

Epicutaneous application of acrylates and related compounds 14 and 7 days before sensitization with either methyl acrylate or trimethylol propane triacrylate induced tolerance to the resultant contact reactions. This tolerance could not be correlated with either the degree of cross reactivity between these compounds or with their ability to react covalently with amino or sulphydryl groups of proteins. These results are discussed in relation to other epicutaneous tolerizers in the dinitrobenzene and poison ivy systems.

Acrylates↗
PubMed1983

A comparison of the conjugation of DNTB and other dinitrobenzenes with free protein radicals and their ability to sensitize or tolerize.

Of several dinitrobenzenes tested, 2,4-dinitrothiocyanatebenzene (DNTB) was found to be the only one that did not induce contact sensitivity when applied to the guinea pig ear epicutaneously, but when applied epicutaneously it induced tolerance to 2,4-dinitrofluorobenzene (DNFB). The manner in which DNFB, DNTB, and other dinitrobenzene compounds conjugated in vitro to soluble proteins, at physiologic pH, was examined. By measuring the free amino and sulfydryl radicals in the protein before and after conjugation, it was possible to determine to which groups the hapten was bound. It was found that although all the haptens bound to the free sulfydryl groups, DNTB was the only one that did not bind to amino groups. It is suggested that to be an epicutaenous tolerizer, as opposed to sensitizer, a hapten should bind to sulfydryl groups exclusively. It is hoped that a search for agents binding in a similar manner will reveal epicutaneous tolerizers for important industrial sensitizers.

Animals↗
PubMed1966

Total oral health.

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Congresses as Topic↗