213 research outputs found

    SYSTEM AND METHODS FOR VENTILATION THROUGH A BODY CAVITY

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    A system and methods for the delivery of oxygen through a body cavity of a subject using oxygen microbubbles . Through circulation of oxygen microbubbles through the body cavity , oxygen and carbon dioxide exchange may occur . Overall improvement in extending survival rate time during emergency situations caused by pulmonary or similar oxygen - intake restricting injury and / or failure may be achieved through use of the invented system and methods

    Phylogenetic relationships within the primitive acanthomorph fish genus Polymixia, with changes to species composition and geographic distributions

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    The genus Polymixia is the only survivor of a Late Cretaceous marine fish radiation and is often said to be the most primitive living acanthomorph (i.e., Polymixia possesses the greatest number of primitive character states for Acanthomorpha). Recent studies, including this one, place Polymixia as the sister to all other Paracanthopterygii. Despite its importance, most species of Polymixia are extremely difficult to discriminate on the basis of morphology. As a result, the number of valid species is uncertain. Moreover, there has never been a phylogenetic analysis of the genus. Thus, a molecular phylogenetic study was needed to clarify species boundaries and to resolve relationships within the genus. Tissue or DNA samples backed by museum vouchers were obtained for most species, with additional samples from new geographic areas representing specimens with distinctively different meristics and uncertain identifications. Seven loci (five nuclear and two mitochondrial) were sequenced, from which Bayesian and maximum-likelihood trees were generated. Results reveal nine species-level clades, of which five represent previously known species (Polymixia berndti, P. japonica, P. longispina, P. lowei, and P. nobilis). Surprisingly, results also reveal four previously unknown species-level clades, one close to P. lowei, one close to P. nobilis, and two new species clades related to P. japonica. The species clades are distinguished by their phylogenetic histories, sequence differences, geographic distributions, and morphologies. The clade containing P. berndti is recovered as the sister to all other species of Polymixia. Its genetic variability suggests that it might contain two or more species and it is referred to here as a “species complex”. Polymixia nobilis, the type species, was previously thought to be restricted to the Atlantic, but is now shown to be widespread in the Pacific and possibly in the Indian Ocean. Specimens from waters off Australia identified as P. busakhini actually belong to P. nobilis. In contrast, P. japonica is confirmed only in the area near Japan and the East China Sea; other more distant records are misidentifications. Wide (antipodal) geographic distributions are seen in several clades, including P. nobilis, the P. berndti species complex, and the P. japonica species group. The new phylogeny helps explain the evolution of some morphological characters previously used to distinguish groups of species, particularly dorsal-fin soft-ray count, shape of rows of scale ctenii, and number of pyloric caec

    Seasonal, Taxonomic, and Local Habitat Components of Bird-window Collisions on an Urban University Campus in Cleveland, OH

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    Author Institution: Department of Biological, Geological & Environmental Sciences, Cleveland State UniversityAuthor Institution: Department of Ornithology, Cleveland Museum of Natural HistoryMigrating birds congregate near the shores of Lake Erie during migration and may be funneled through small green spaces within the urban matrix of Great Lake coastal cities, where they are at risk of higher mortality from manmade structures. Bird deaths due to window collisions were assessed amongst a complex of low-rise buildings (<30 m) on a university campus in Cleveland, OH. A 1.8 km route was surveyed three times per week during a 12-month period. Deaths were tested against null hypotheses that season, taxonomy, and building attributes had no significant relationship with avian mortality. We recovered 271 dead birds of 50 species, all of which were consistent with regional bird lists and Neotropical-Nearctic and North American migrants through Ohio. Deaths occurred non-randomly by week, month, and migratory status with 90 percent of deaths occurring during spring and fall migrations. Consequently, migrants (warblers: 34 percent of species richness, 30 percent of deaths; sparrows: 14 percent of richness, 35 percent of deaths) were observed nine times more frequently than residents. Neotropical-Nearctic migrant species outnumbered North American migrant species. Although there was no statistical difference between the compass direction of a building facade and the number of deaths, deaths were not randomly distributed among campus buildings. Rather, significantly more deaths occurred at facades with higher percentages of glass. The presence of trees within 5 m of a window and the reflection of trees in windows were also associated with a greater risk of fatality. A better understanding of the factors associated with bird-window collisions is a pressing issue in the conservation of migratory birds

    Evaluation of Peritoneal Microbubble Oxygenation Therapy in a Rabbit Model of Hypoxemia

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    Alternative extrapulmonary oxygenation technologies are needed to treat patients suffering from severe hypoxemia refractory to mechanical ventilation. We previously demonstrated that peritoneal microbubble oxygenation (PMO), in which phospholipid-coated oxygen microbubbles (OMBs) are delivered into the peritoneal cavity, can successfully oxygenate rats suffering from a right pneumothorax. This study addressed the need to scale up the procedure to a larger animal with a splanchnic cardiac output similar to humans. Our results show that PMO therapy can double the survival time of rabbits experiencing complete tracheal occlusion from6.6 ± 0.6 min for the saline controls to 12.2 ± 3.0 min for the bolus PMO-treated cohort. Additionally, we designed and tested a new peritoneal delivery system to circulate OMBs through the peritoneal cavity. Circulation achieved a similar survival benefit to bolus delivery under these conditions. Overall, these results support the feasibility of the PMO technology to provide extrapulmonary ventilation for rescue of severely hypoxic patients

    Regulation of Ahr signaling by Nrf2 during development : effects of Nrf2a deficiency on PCB126 embryotoxicity in zebrafish (Danio rerio)

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    Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Aquatic Toxicology 167 (2015): 157-171, doi:10.1016/j.aquatox.2015.08.002.The embryotoxicity of co-planar PCBs is regulated by the aryl hydrocarbon receptor (Ahr), and has been reported to involve oxidative stress. Ahr participates in crosstalk with another transcription factor, Nfe2l2, or Nrf2. Nrf2 binds to antioxidant response elements to regulate the adaptive response to oxidative stress. To explore aspects of the crosstalk between Nrf2 and Ahr and its impact on development, we used zebrafish (Danio rerio) with a mutated DNA binding domain in Nrf2a (nrf2afh318/fh318), rendering these embryos more sensitive to oxidative stress. Embryos were exposed to 2 nM or 5 nM PCB126 at 24 hours post fertilization (prim-5 stage of pharyngula) and examined for gene expression and morphology at 4 days post fertilization (dpf; protruding –mouth stage). Nrf2a mutant eleutheroembryos were more sensitive to PCB126 toxicity at 4 dpf, and in the absence of treatment also displayed some subtle developmental differences from wildtype embryos, including delayed inflation of the swim bladder and smaller yolk sacs. We used qPCR to measure changes in expression of the nrf gene family, keap1a, keap1b, the ahr gene family, and known target genes. cyp1a induction by PCB126 was enhanced in the Nrf2a mutants (156-fold in wildtypes vs. 228-fold in mutants exposed to 5 nM). Decreased expression of heme oxygenase (decycling) 1 (hmox1) in the Nrf2a mutants was accompanied by increased nrf2b expression. Target genes of Nrf2a and AhR2, NAD(P)H:quinone oxidoreductase 1 (nqo1) and glutathione S-transferase, alpha-like (gsta1), showed a 2-5-fold increase in expression in the Nrf2a mutants as compared to wildtype. This study elucidates the interaction between two important transcription factor pathways in the developmental toxicity of co-planar PCBs.University of Massachusetts Amherst Commonwealth Honors College Research grant (to M.R.), National Institutes of Health grants R01ES016366 (MEH), R01ES006272 (MEH), and F32ES017585 (ART-L)

    Methods of Generating Submicrometer Phase-Shift Perfluorocarbon Droplets for Applications in Medical Ultrasonography

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    Continued advances in the field of ultrasound and ultrasound contrast agents have created new approaches to imaging and medical intervention. Phase-shift perfluorocarbon droplets, which can be vaporized by ultrasound energy to transition from the liquid to the vapor state, are one of the most highly researched alternatives to clinical ultrasound contrast agents (i.e., microbubbles). In this paper, part of a special issue on methods in biomedical ultrasonics, we survey current techniques to prepare ultrasound-activated nanoscale phase-shift perfluorocarbon droplets, including sonication, extrusion, homogenization, microfluidics, and microbubble condensation. We provide example protocols and discuss advantages and limitations of each approach. Finally, we discuss best practice in characterization of this class of contrast agents with respect to size distribution and ultrasound activation

    Theranostic Oxygen Delivery Using Ultrasound and Microbubbles

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    Means to overcome tumor hypoxia have been the subject of clinical investigations since the 1960's; however these studies have yet to find a treatment which is widely accepted. It has been known for nearly a century that hypoxic cells are more resistant to radiotherapy than aerobic cells, and tumor hypoxia is a major factor leading to the resistance of tumors to radiation treatment as well as several cytotoxic agents. In this manuscript, the application of ultrasound combined with oxygen-carrier microbubbles is demonstrated as a method to locally increase dissolved oxygen. Microbubbles can also be imaged by ultrasound, thus providing the opportunity for image-guided oxygen delivery. Simulations of gas diffusion and microbubble gas exchange show that small amounts (down to 5 vol%) of a low-solubility osmotic gas can substantially increase microbubble persistence and therefore production rates and stability of oxygen-carrier microbubbles. Simulations also indicate that the lipid shell can be engineered with long-chain lipids to increase oxygen payload during in vivo transit. Experimental results demonstrate that the application of ultrasound to destroy the microbubbles significantly enhances the local oxygen release. We propose this technology as an application for ultrasound image-guided release of oxygen directly to hypoxic tissue, such as tumor sites to enhance radiotherapy
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