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by Joan T. Hare. / Thesis (M.S.)--Florida State University. / Bibliography: leaves 55-58. / Florida State University faculty publication.

Investigations were conducted to characterize endothelial cell (EC) movement and barrier function in vitro and to investigate their potential interrelationship. Specifically, the mediation of EC movement and barrier function by vasoactive amines, and the relevance of this mediation to a potential mechanism by which blood platelets may help maintain microvascular integrity, was examined. The effects of the platelet constituents serotonin (5-HT) and norepinephrine (NE) and the effects of histamine on bovine aortic endothelial cell (BAEC) and vascular smooth muscle cell (VSMC) movement were quantitated using a phagokinetic tracking assay. BAEC movement was significantly reduced by 5-HT, NE, and histamine, while VSMC motility was significantly enhanced by 5-HT and histamine, but reduced by NE. The use of specific receptor antagonists revealed that the 5-HT- and NE-associated inhibition of BAEC movement may be mediated by beta-adrenergic receptors, and the histamine-associated inhibition may be partially mediated by H-1 receptors. An assay to measure the passage of a trypan blue dye-bovine serum albumin conjugate (TB-BSA) across cells grown on microcarriers was used to compare the barriers provided by EC and other cell types. VSMC or 3T3 fibroblasts impeded TB-BSA diffusion significantly less than BAEC, suggesting that barrier formation may be an EC-specific phenomenon. Treatment of BAEC with 5-HT or NE significantly impeded TB-BSA diffusion relative to untreated controls. In contrast, histamine treatment significantly increased TB-BSA diffusion. The amine-associated effects were dose-dependent and cell-specific, and in some cases appeared to be receptor-mediated. BAEC and pulmonary microvessel EC (PMEC) barriers were quantitatively comparable, but significantly more permeable than that observed for cerebral microvessel EC (CMEC). Glutaraldehyde fixation and low temperature reduced TB-BSA passage across BAEC by <30%, indicating that the bulk of tracer movement occurred via intercellular diffusion. Treatment with cytochalasin resulted in significant BAEC and CMEC barrier loss, suggesting that microfilament bundles are involved EC junctional maintenance. Collectively, the results suggest a dynamic model of vascular permeability in which intercellular macromolecular diffusion may be regulated by EC junctional apposition, and responsive to physiologic -agents that affect EC movement.

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published_or_final_version / Zoology / Doctoral / Doctor of Philosophy

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Orientador: Estela Kaminagakura Tango / Banca: Cristiane Yumi Koga-Ito / Banca: Felipe Eduardo de Oliveira / Resumo: As nanofibras (NF) podem ser sintetizadas por meio de eletrofiação, um método simples que permite incorporação de fármacos em biopolímeros que apresentam a vantagem de serem liberados de forma gradual. Policaprolactona (PCL) apresenta a vantagem de poder ser eletrofiada permitindo a incorporação de fármacos. Os ácidos retinoicos são fármacos empregados no tratamento de osteossarcoma, mas, apresentam efeitos colaterais. O ATRA (all-trans-retinoic-acid) é o mais comum entre os retinoides. Os objetivos deste estudo foram: sintetizar e caracterizar NF, incorporar o fármaco a elas e verificar a liberação ao meio de cultura; realizar testes de citoxicidade e genotoxicidade tais como: crescimento, integridade, viabilidade e micronúcleo de células MG63 tratadas com NF incorporada com ATRA e analisar a secreção das citocinas pró inflamatórias: IL-1β, IL-6 e TNF-α por meio do teste ELISA. As NF sintetizadas por meio da eletrofiação foram caracterizadas morfologicamente e bioquimicamente por meio de microscopia eletrônica de varredura (MEV) e estudo do espectro de infravermelho da transformada de Fourrier (FTIR): Os testes in vitro foram realizados utilizando uma linhagem de células imortalizadas de osteossarcoma, MG63. Os ensaios incluídos nesse estudo foram divididos em grupos compostos por: [C (controle puro), ATRA (controle positivo), NF (controle negativo) e NF + ATRA (grupo experimental).] Em todos os grupos foram realizados testes de viabilidade celular (MTT), micronúcleo e ELISA... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Nanofibers (NF) can be synthesized by electro-spinning, a simple method that allows incorporation of drugs into biopolymers that have the advantage of being released gradually. Polycaprolactone (PCL) has the advantage that it can be electrophied allowing the incorporation of drugs. Retinoic acids are drugs used in the treatment of osteosarcoma, but have side effects. ATRA (all-trans-retinoicacid) is the most common retinoid. The objectives of this study were: to synthesize and characterize NF, to incorporate the drug to them and to verify the release to the culture medium; perform cytotoxicity and genotoxicity tests such as: growth, integrity, viability and micronucleus of N63-treated NF-treated cells with ATRA and to analyze the secretion of pro-inflammatory cytokines: IL-1β, IL-6 and TNFα by the ELISA . The NF synthesized by electrophilation were characterized morphologically and biochemically by scanning electron microscopy (SEM) and Fourrier Transform Infrared Spectrum (FTIR) study: In vitro tests were performed using an immortalized osteosarcoma cell line, MG63. The trials included in this study were divided into groups composed of: C (pure control), ATRA (positive control), NF (negative control) and NF + ATRA (experimental group). All groups were tested for cell viability (MTT), micronucleus and ELISA under the times of 3, 7 and 14 days. Release of the drug through the NF + ATRA system was confirmed by FTIR. The other results were evaluated using the oneway ANOVA test, ... (Complete abstract click electronic access below) / Mestre

The study of the aging process is the investigation as to how the passage of time affects cells, organs, and organisms. Aging is a very complex and incompletely understood phenomenon. This is reflected by the number of theories attributing aging to a variety of causative factors such as: (1) the somatic mutations occurring spontaneously or produced by ionizing radiation, which are thought to have some effect on again but are not responsible for the normal process; (2) the alteration of macromolecules as the cells of an organism age forming neoantigens and functioning in the autoimmune reactions; the Cross-linkage theory which maintains that large molecules necessary for life processes, such as deoxyribonucleic acid (DNA) and collagen are progressively immobilized in all cells and tissues by cross-linkage. Aging has also been studied in relation to the self-destructive “programmed death” characteristic of some parts of embryological development. Moreover, senescent changes involve different kinds of cells and tissues in the organism and therefore various mechanisms must occur. For example, the aging of postmitotic cells, such as neurons and cardiac cells probably proceeds by a different mechanism than the proliferating tissues, such as the skin, the gut lining, and the blood forming elements. It is apparent that there is probably no single aging process, but a series of aging processes which natural selection would tend to synchronize even if the causes were physiologically independent.