193 research outputs found
Biological Effects of Dispersants and Dispersed Oil in Surface and Deep Ocean Species
Beginning with the use of industrial-strength detergents, dispersing agents have been employed in spill response for decades. The Corexit series of agents in common use today generally consist of non-ionic and/or anionic surfactants in a solvent base designed to enhance miscibility under varying temperature and salinity conditions; cationic surfactants tend to be too toxic for use. While dispersants generally serve to decrease the interfacial surface tension of oil, thus facilitating its weathering under low-energy conditions, their surface-active nature also causes their interaction with cell surfaces – those of single-celled organisms as well as the gills of vertebrates and invertebrates
End organ damage in the metabolic syndrome and diabetes mellitus : biochemical and magnetic resonance imaging studies
The focus of this thesis was to evaluate biomarkers of cardiovascular end organ damage in the metabolic syndrome and diabetes mellitus. We performed cross-sectional studies with biochemical and magnetic resonance imaging (MRI) techniques. We have demonstrated that insulin resistance is a strong risk predictor for CVD and we provided a novel link between inflammation and angiopoietin-like protein 4 (ANGPTL4) expression by showing that ANGPTL4 levels in humans are related to systemic inflammation and inflammatory stimuli increased ANGPTL4 expression using human macrophages in vitro. The imaging studies described in this thesis extend the knowledge of end organ damage and explored the relation with aortic stiffness. The impact of type 1 diabetes mellitus (T1DM) on regional grey matter was investigated and showed atrophy of all subcortical grey matter structures but the amygdala. By showing an association of aortic stiffness with subtle microstructural deficits in T1DM and kidney function in patients with hypertension the close link between aortic stiffness and the microcirculation is demonstrated. Furthermore regional and individual differences in response to an oral glucose load in MR assessed aortic stiffness were observed, which may open new future research paths possibly linking inter-individual variation in regional vascular response and CVD.UBL - phd migration 201
PAH- and PCB-induced Alterations of Protein Tyrosine Kinase and Cytokine Gene Transcription in Harbor Seal (Phoca Vitulina) PBMC
Mechanisms underlying in vitro immunomodulatory effects of polycyclic
aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were
investigated in harbor seal peripheral leukocytes, via real-time PCR. We examined
the relative genetic expression of the protein tyrosine kinases
(PTKs) Fyn and Itk,
which play a critical role in T cell activation, and IL-2, a cytokine of central
importance in initiating adaptive immune responses. IL-1, the macrophage-derived
pro-inflammatory cytokine of innate immunity, was also included as a measure
of macrophage function. Harbor seal PBMC were exposed to the prototypic
immunotoxic PAH benzo[a]pyrene (BaP), 3,3',4,4',5,5'-hexachlorobiphenyl
(CB-169), a model immunotoxic PCB, or DMSO (vehicle control). Exposure of
Con A-stimulated harbor seal PBMC to both BaP and CB-169 produced
significantly altered expression in all four targets relative to vehicle controls. The
PTKs Fyn and Itk were both up-regulated following exposure to BaP and CB-169.
In contrast, transcripts for IL-2 and IL-1 were decreased relative to controls by both
treatments. Our findings are consistent with those of previous researchers working
with human and rodent systems and support a hypothesis of contaminant-altered
lymphocyte function mediated (at least in part)
by disruption of T cell receptor (TCR) signaling and cytokine production
Proliferative Responses of Harbor Seal (Phoca vitulina) T Lymphocytes to Model Marine Pollutants
In recent years, population declines related to viral outbreaks in marine mammals have been associated with polluted coastal waters and high tissue concentrations of certain persistent, lipophilic contaminants. Such observations suggest a contributing role of contaminant-induced suppression of cell-mediated immunity leading to decreased host resistance. Here, we assessed the effects of the prototypic polycyclic aromatic hydrocarbon (PAH), benzo[a]pyrene (B[a]P), and two polychlorinated biphenyls (PCBs), CB-156 and CB-80, on the T-cell proliferative response to mitogen in harbor seal peripheral lymphocytes. Despite the variability associated with our samples from free-ranging harbor seals, we observed a clear suppressive effect of B[a]P (10 uM) exposure on T cell mitogenesis. Exposures to 10 uM CB-156 and CB-80, and 1.0 and 0.1 uM B[a]P, did not produce significant depression in lymphoproliferation. Exposure to the model PAH at 10 uM resulted in a 61% (range 34-97%) average reduction in lymphoproliferation. We were able to rule out a direct cytotoxic effect of B[a]P, indicating that observed effects were due to altered T cell function. Based on our in vitro results, we hypothesize that extensive accumulation of PAH by top-trophic-level marine mammals could alter T cell activation in vivo and impaired cell-mediated immunity against viral pathogens
The cinepheur: post-cinematic passage, post-perceptual passage
This thesis develops a hermeneutic commensurate with the aesthetic and ontological challenges of what Steven Shaviro describes as a post-cinematic media ecology, and Shane Denson describes as an emergent post-perceptual media ecology. I consider canonicity and cinephilia as frustrated efforts to contain and comprehend this new cinematic media object, offering a third unit of interpretation in their place, which I describe as the cinetopic anecdote. I associate the cinetopic anecdote with a particular way of moving between cinema and cinematic infrastructure, which I label cinetopic passage, and with a subject position that I label the cinepheur. Drawing on Walter Benjamin’s theory of the flâneur, I argue that the cinetopic anecdote precludes the extraction of a privileged cinematic moment in the manner characteristic of Christian Keathley’s cinephilic anecdote, but instead compels the cinepheur to instantiate, embody or physically recreate the infrastructural conditions that produced it, dovetailing production and consumption into what Axel Bruns has described as the emergent category of produsage; “unfinished artifacts, continuing process.” Having elaborated the cinetopic anecdote, I apply it to postmodern, post-cinematic and post-perceptual media ecologies, in order to evoke the peculiar forms of attachment and obsession bound up with the Criterion and Netflix platforms. In the process, I draw on Franco Moretti’s conception of distant reading to frame the cinetopic anecdote as a unit of distant viewing, offering distant viewings of Angela Christlieb and Stephen Kijak’s Cinemania, Sidney Lumet’s Garbo Talks and Pier Paolo Pasolini’s Salò, or The 120 Days of Sodom. Just as distant reading takes “the great unread” as its object of enquiry, so the cinetopic anecdote speaks to a media ecology preoccupied by the “great unviewed,” in which cinematic scarcity increasingly ramifies as an elegaic object
Proteomic identification, cDNA cloning and enzymatic activity of glutathione S-transferases from the generalist marine gastropod, Cyphoma gibbosum
Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Archives of Biochemistry and Biophysics 478 (2008): 7-17, doi:10.1016/j.abb.2008.07.007.Glutathione S-transferases (GST) were characterized from the digestive gland of
Cyphoma gibbosum (Mollusca; Gastropoda), to investigate the possible role of these
detoxification enzymes in conferring resistance to allelochemicals present in its gorgonian coral
diet. We identified the collection of expressed cytosolic Cyphoma GST classes using a
proteomic approach involving affinity chromatography, HPLC and nanospray liquid
chromatography-tandem mass spectrometry (LC-MS/MS). Two major GST subunits were
identified as putative mu-class GSTs; while one minor GST subunit was identified as a putative
theta-class GST, apparently the first theta-class GST identified from a mollusc. Two Cyphoma
GST cDNAs (CgGSTM1 and CgGSTM2) were isolated by RT-PCR using primers derived from
peptide sequences. Phylogenetic analyses established both cDNAs as mu-class GSTs and
revealed a mollusc-specific subclass of the GST-mu clade. These results provide new insights
into metazoan GST diversity and the biochemical mechanisms used by marine organisms to cope
with their chemically defended prey.Support was provided by the WHOI-Cole Ocean Ventures Fund (KEW), the WHOI Ocean Life
Institute (KEW and MEH), a grant from Walter A. and Hope Noyes Smith (MEH), the National
Science Foundation Graduate Research Fellowship (KEW), and by the National Institutes of
Health (P42-ES007381 and R01-ES015912 to JVG)
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