26 resultados para Health Sciences, Dentistry|Health Sciences, Public Health|Health Sciences, Immunology

em Digital Commons at Florida International University


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A recent multi-country study on hormonal contraceptives (HC) and HIV acquisition and transmission among African HIV-serodiscordant couples reported a statistically significant doubling of risk for HIV acquisition among women as well as transmission from women to men for injectable contraceptives. Together with a prior cohort study on African women seeking health services, these data are the strongest yet to appear on the HC-HIV risk. This paper will briefly review the Heffron study strengths and relevant biological and epidemiologic evidence; address the futility of further trials; and propose instead an alternative framework for next steps. The weight of the evidence calls for a discontinuation of progestin-dominant methods. We propose here five types of productive activities: (1) scaling injectable hormones down and out of the contraceptive mix; (2) strengthening and introducing public health strategies with proven potential to reduce HIV spread; (3) providing maximal choice to reduce unplanned pregnancy, starting with quality sexuality education through to safe abortion access; (4) expanding provider training, end-user counseling and access to male and female barriers, with a special renewed focus on female condom; (5) initiating a serious research agenda to determine anti-STI/HIV potential of the contraceptive cervical cap. Trusting women to make informed choices is critical to achieve real progress in dual protection.

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To assess the role of shark cartilage as an immune modulator, acid, salt-soluble, and phosphate-buffered saline extracts were prepared from three different commercial sources (SL, TL, FDC) of cartilage and used to stimulate human leukocytes in vitro. Duplicate leukocyte cultures were set up, each containing 50 $\mu$l of endotoxin-free extract, 200 $\mu$l of cell suspension (2.4-2.5 $\times$ 10$\sp5$ cells) and 100 $\mu$l of medium and incubated at 37$\sp\circ$C. Cultures stimulated with LPS (5 $\mu$g/ml) or medium served as the positive and negative controls, respectively. Culture supernatants were assayed for TNF$\alpha$ by ELISA. Cartilage extracts stimulated cells to release significant levels of TNF$\alpha$ (p $<$.005); the highest response was obtained with the acid extract of SL cartilage. In comparison, response to corresponding extracts of bovine cartilage was lower (p $<$.05). The stimulatory activity was reduced (85%) following proteolytic digestion, and lost when extract was heated (60$\sp\circ$C, 20 min) or treated with urea (6M), suggesting that the active component(s) is a protein. ^

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The Fas system, comprising the Fas receptor (Fas/Apo-1/CD95) and its ligand, Fas ligand (FasL), is a central mediator of programmed cell death in various physiological and pathological processes. FasL exists as transmembrane and soluble forms and induces apoptosis on crosslinking with Fas receptor. Recent evidence indicated that tumor cells exploit this system for their immunologic escape that includes the loss of Fas and the gain of FasL expression. In the present study, nine mouse tumor cell lines of diverse origin were examined immunocytochemically for the expression of Fas and FasL. Nine of nine cell lines expressed FasL, and five of nine cell lines expressed Fas. FasL expression in these tumor cell lines was demonstrated to be functional by its induction of apoptosis in Fas-sensitive target cells in coculture experiments. These results suggest that FasL may be a prevalent mediator of immune privilege in mouse malignancies, and support the recently proposed "counterattack model" for local elimination of tumor-reactive immune cells by tumor cell-derived FasL.^ Culture supernatant of four cell lines expressing FasL showed cytotoxic effect on Fas-sensitive target cells, indicating the possibility of secreted FasL in the medium. The Fas-expressing cell lines were sensitized to anti-Fas antibody cytotoxicity following treatment with IL-2 and IFN-$\gamma$, suggesting cytokine stimulation as an effective target for future immunotherapeutic strategies. ^

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The health status of wild and captive Atlantic Bottlenose dolphins ( Tersiops truncatis) is difficult to ascertain. Mass strandings of these animals have been attributed to pollutants, as well as bacterial infections. Using human Enzyme Linked Immuno-Assays (ELISA) for immunological cytokines, I measured soluble cytokine levels with respect to their health status. In a retrospective analysis of dolphin sera, there was a trend of higher cytokine levels in “sick” animals. I cultured dolphin lymphocytes in the presence of a mitogen (PHA), a super antigen (Staph-A), Lipopolysaccharide (LPS), and a calcium flux inducer (PMA). Levels of messenger RNA, from these cultured cells, were assayed with Polymerase Chain Reaction (PCR) using primers for the human cytokines IL-2, IL-4, IL-6, IL-10, Tumor Necrosis Factor, and Interferon gamma. Only IL-4, IL-6, and IL-10 messages were obtained, inferring similar nucleotide homology to the human primer sequences. The PCR products were sequenced. Sixteen IL-4 sequences, twelve IL-6 sequences and seven IL-10 sequences were obtained and analyzed. Each cytokine exhibited the same nucleotide sequence in all dolphins examined. There was no difference in the cytokine profile in response to the various stimuli. The derived amino acid composition for each of the dolphin cytokines was used for molecular modeling, which showed that dolphin IL-4, IL-6, and IL-10 were structurally similar to the corresponding proteins of Perissodactyla. ^

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In many vertebrate and invertebrate species mediators of innate immunity include antimicrobial peptides (AMPs) such as peptide fragments of histones and other proteins with previously ascribed different functions. Shark AMPs have not been described and this research examines the antibacterial activity of nurse shark (Ginglymostoma cirratum) peripheral blood leukocyte lysates. Screening of lysates prepared by homogenizing unstimulated peripheral blood leukocytes identified muramidase (lysozyme-like) and non-muramidase antibacterial activity. Lysates were tested for lysozyme using the lysoplate assays, and antibacterial (AB) activity was assayed for by a microdilution growth assay that was developed using Planococcus citreus as the target bacterium. Fractionation of crude lysates by ion exchange and affinity chromatography was followed by a combination of SDS-PAGE with LC/MS-MS and/or N-terminal sequence analysis of low molecular weight protein bands (<20 kDa). This yielded several peptides with amino acid sequence similarity to lysozyme, ubiquitin, hemoglobin, human histones H2A, H2B and H4 and to antibacterial histone fragments of the catfish and the Asian toad. Not all peptide sequences corresponded to peptides potentially antibacterial. The correlation of a specific protein band in active lysate fractions was accomplished by employing the acid-urea gel overlay assays in which AB activity was seen as zones of growth inhibition on a lawn of P. citreus at a position corresponding to that of the putative AB protein band. This study is the first to describe putative AMPs in the shark and their potential role in innate immunity.^

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Press Release from Florida International University 's Office of Media Relations announcing the appointment of Dr. John Rock as founding Dean of Florida International University 's College of Medicine.

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Fact sheet describing the desired qualifications for the Academic Health Sciences Master Planning Initiative team.