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Sample records for regenerating avian cochlea

  1. Depletion of resident macrophages does not alter sensory regeneration in the avian cochlea.

    Directory of Open Access Journals (Sweden)

    Mark E Warchol

    Full Text Available Macrophages are the primary effector cells of the innate immune system and are also activated in response to tissue injury. The avian cochlea contains a population of resident macrophages, but the precise function of those cells is not known. The present study characterized the behavior of cochlear macrophages after aminoglycoside ototoxicity and also examined the possible role of macrophages in sensory regeneration. We found that the undamaged chick cochlea contains a large resting population of macrophages that reside in the hyaline cell region, immediately outside the abneural (inferior border of the sensory epithelium. Following ototoxic injury, macrophages appear to migrate out of the hyaline cell region and towards the basilar membrane, congregating immediately below the lesioned sensory epithelium. In order to determine whether recruited macrophages contribute to the regeneration of sensory receptors, we quantified supporting cell proliferation and hair cell recovery after the elimination of most resident macrophages via application of liposomally-encapsulated clodronate. Examination of macrophage-depleted specimens at two days following ototoxic injury revealed no deficits in hair cell clearance, when compared to normal controls. In addition, we found that elimination of macrophages did not affect either regenerative proliferation of supporting cells or the production of replacement hair cells. However, we did find that macrophage-depleted cochleae contained reduced numbers of proliferative mesothelial cells below the basilar membrane. Our data suggest that macrophages are not required for normal debris clearance and regeneration, but that they may play a role in the maintenance of the basilar membrane.

  2. Cisplatin ototoxicity blocks sensory regeneration in the avian inner ear.

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    Slattery, Eric L; Warchol, Mark E

    2010-03-03

    Cisplatin is a chemotherapeutic agent that is widely used in the treatment of solid tumors. Ototoxicity is a common side effect of cisplatin therapy and often leads to permanent hearing loss. The sensory organs of the avian ear are able to regenerate hair cells after aminoglycoside ototoxicity. This regenerative response is mediated by supporting cells, which serve as precursors to replacement hair cells. Given the antimitotic properties of cisplatin, we examined whether the avian ear was also capable of regeneration after cisplatin ototoxicity. Using cell and organ cultures of the chick cochlea and utricle, we found that cisplatin treatment caused apoptosis of both auditory and vestibular hair cells. Hair cell death in the cochlea occurred in a unique pattern, progressing from the low-frequency (distal) region toward the high-frequency (proximal) region. We also found that cisplatin caused a dose-dependent reduction in the proliferation of cultured supporting cells as well as increased apoptosis in those cells. As a result, we observed no recovery of hair cells after ototoxic injury caused by cisplatin. Finally, we explored the potential for nonmitotic hair cell recovery via activation of Notch pathway signaling. Treatment with the gamma-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester failed to promote the direct transdifferentiation of supporting cells into hair cells in cisplatin-treated utricles. Taken together, our data show that cisplatin treatment causes maintained changes to inner ear supporting cells and severely impairs the ability of the avian ear to regenerate either via proliferation or by direct transdifferentiation.

  3. Wnt activation followed by Notch inhibition promotes mitotic hair cell regeneration in the postnatal mouse cochlea

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    Li, Wenyan; Chen, Yan; Zhang, Shasha; Tang, Mingliang; Sun, Shan; Chai, Renjie; Li, Huawei

    2016-01-01

    Hair cell (HC) loss is the main cause of permanent hearing loss in mammals. Previous studies have reported that in neonatal mice cochleae, Wnt activation promotes supporting cell (SC) proliferation and Notch inhibition promotes the trans-differentiation of SCs into HCs. However, Wnt activation alone fails to regenerate significant amounts of new HCs, Notch inhibition alone regenerates the HCs at the cost of exhausting the SC population, which leads to the death of the newly regenerated HCs. Mitotic HC regeneration might preserve the SC number while regenerating the HCs, which could be a better approach for long-term HC regeneration. We present a two-step gene manipulation, Wnt activation followed by Notch inhibition, to accomplish mitotic regeneration of HCs while partially preserving the SC number. We show that Wnt activation followed by Notch inhibition strongly promotes the mitotic regeneration of new HCs in both normal and neomycin-damaged cochleae while partially preserving the SC number. Lineage tracing shows that the majority of the mitotically regenerated HCs are derived specifically from the Lgr5+ progenitors with or without HC damage. Our findings suggest that the co-regulation of Wnt and Notch signaling might provide a better approach to mitotically regenerate HCs from Lgr5+ progenitor cells. PMID:27564256

  4. Cisplatin Ototoxicity Blocks Sensory Regeneration in the Avian Inner Ear

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    Slattery, Eric L.; Warchol, Mark E.

    2010-01-01

    Cisplatin is a chemotherapeutic agent that is widely-used in the treatment of solid tumors. Ototoxicity is a common side effect of cisplatin therapy, and often leads to permanent hearing loss. The sensory organs of the avian ear are able to regenerate hair cells after aminoglycoside ototoxicity. This regenerative response is mediated by supporting cells, which serve as precursors to replacement hair cells. Given the antimitotic properties of cisplatin, we examined whether the avian ear was al...

  5. Epigenetic influences on sensory regeneration: histone deacetylases regulate supporting cell proliferation in the avian utricle.

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    Slattery, Eric L; Speck, Judith D; Warchol, Mark E

    2009-09-01

    The sensory hair cells of the cochlea and vestibular organs are essential for normal hearing and balance function. The mammalian ear possesses a very limited ability to regenerate hair cells and their loss can lead to permanent sensory impairment. In contrast, hair cells in the avian ear are quickly regenerated after acoustic trauma or ototoxic injury. The very different regenerative abilities of the avian vs. mammalian ear can be attributed to differences in injury-evoked expression of genes that either promote or inhibit the production of new hair cells. Gene expression is regulated both by the binding of cis-regulatory molecules to promoter regions as well as through structural modifications of chromatin (e.g., methylation and acetylation). This study examined effects of histone deacetylases (HDACs), whose main function is to modify histone acetylation, on the regulation of regenerative proliferation in the chick utricle. Cultures of regenerating utricles and dissociated cells from the utricular sensory epithelia were treated with the HDAC inhibitors valproic acid, trichostatin A, sodium butyrate, and MS-275. All of these molecules prevent the enzymatic removal of acetyl groups from histones, thus maintaining nuclear chromatin in a "relaxed" (open) configuration. Treatment with all inhibitors resulted in comparable decreases in supporting cell proliferation. We also observed that treatment with the HDAC1-, 2-, and 3-specific inhibitor MS-275 was sufficient to reduce proliferation and that two class I HDACs--HDAC1 and HDAC2--were expressed in the sensory epithelium of the utricle. These results suggest that inhibition of specific type I HDACs is sufficient to prevent cell cycle entry in supporting cells. Notably, treatment with HDAC inhibitors did not affect the differentiation of replacement hair cells. We conclude that histone deacetylation is a positive regulator of regenerative proliferation but is not critical for avian hair cell differentiation.

  6. Hair cell regeneration in the avian auditory epithelium.

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    Stone, Jennifer S; Cotanche, Douglas A

    2007-01-01

    Regeneration of sensory hair cells in the mature avian inner ear was first described just over 20 years ago. Since then, it has been shown that many other non-mammalian species either continually produce new hair cells or regenerate them in response to trauma. However, mammals exhibit limited hair cell regeneration, particularly in the auditory epithelium. In birds and other non-mammals, regenerated hair cells arise from adjacent non-sensory (supporting) cells. Hair cell regeneration was initially described as a proliferative response whereby supporting cells re-enter the mitotic cycle, forming daughter cells that differentiate into either hair cells or supporting cells and thereby restore cytoarchitecture and function in the sensory epithelium. However, further analyses of the avian auditory epithelium (and amphibian vestibular epithelium) revealed a second regenerative mechanism, direct transdifferentiation, during which supporting cells change their gene expression and convert into hair cells without dividing. In the chicken auditory epithelium, these two distinct mechanisms show unique spatial and temporal patterns, suggesting they are differentially regulated. Current efforts are aimed at identifying signals that maintain supporting cells in a quiescent state or direct them to undergo direct transdifferentiation or cell division. Here, we review current knowledge about supporting cell properties and discuss candidate signaling molecules for regulating supporting cell behavior, in quiescence and after damage. While significant advances have been made in understanding regeneration in non-mammals over the last 20 years, we have yet to determine why the mammalian auditory epithelium lacks the ability to regenerate hair cells spontaneously and whether it is even capable of significant regeneration under additional circumstances. The continued study of mechanisms controlling regeneration in the avian auditory epithelium may lead to strategies for inducing

  7. ADAM10 and γ-secretase regulate sensory regeneration in the avian vestibular organs.

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    Warchol, Mark E; Stone, Jennifer; Barton, Matthew; Ku, Jeffrey; Veile, Rose; Daudet, Nicolas; Lovett, Michael

    2017-08-01

    The loss of sensory hair cells from the inner ear is a leading cause of hearing and balance disorders. The mammalian ear has a very limited ability to replace lost hair cells, but the inner ears of non-mammalian vertebrates can spontaneously regenerate hair cells after injury. Prior studies have shown that replacement hair cells are derived from epithelial supporting cells and that the differentiation of new hair cells is regulated by the Notch signaling pathway. The present study examined molecular influences on regeneration in the avian utricle, which has a particularly robust regenerative ability. Chicken utricles were placed in organotypic culture and hair cells were lesioned by application of the ototoxic antibiotic streptomycin. Cultures were then allowed to regenerate in vitro for seven days. Some specimens were treated with small molecule inhibitors of γ-secretase or ADAM10, proteases which are essential for transmission of Notch signaling. As expected, treatment with both inhibitors led to increased numbers of replacement hair cells. However, we also found that inhibition of both proteases resulted in increased regenerative proliferation. Subsequent experiments showed that inhibition of γ-secretase or ADAM10 could also trigger proliferation in undamaged utricles. To better understand these phenomena, we used RNA-Seq profiling to characterize changes in gene expression following γ-secretase inhibition. We observed expression patterns that were consistent with Notch pathway inhibition, but we also found that the utricular sensory epithelium contains numerous γ-secretase substrates that might regulate cell cycle entry and possibly supporting cell-to-hair cell conversion. Together, our data suggest multiple roles for γ-secretase and ADAM10 in vestibular hair cell regeneration. Copyright © 2017. Published by Elsevier Inc.

  8. Hearing and the cochlea

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    ... like structure that contains the receptor organ for hearing. The cochlea contains the spiral organ of Corti, which is the receptor organ for hearing. It consists of tiny hair cells that translate ...

  9. ADAM10 and gamma-secretase regulate sensory regeneration in the avian vestibular organs

    OpenAIRE

    Warchol, M. E.; Stone, J.; Barton, M.; Ku, J.; Veile, R.; Daudet, N.; Lovett, M.

    2017-01-01

    The loss of sensory hair cells from the inner ear is a leading cause of hearing and balance disorders. The mammalian ear has a very limited ability to replace lost hair cells, but the inner ears of non-mammalian vertebrates can spontaneously regenerate hair cells after injury. Prior studies have shown that replacement hair cells are derived from epithelial supporting cells and that the differentiation of new hair cells is regulated by the Notch signaling pathway. The present study examined mo...

  10. Regeneration

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    George A. Schier; Wayne D. Shepperd; John R. Jones

    1985-01-01

    There are basically two approaches to regenerating aspen stands-sexual reproduction using seed, or vegetative regeneration by root suckering. In the West, root suckering is the most practical method. The advantage of having an existing, well established root system capable of producing numerous root suckers easily outweighs natural or artificial reforestation in the...

  11. Finite element coiled cochlea model

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    Isailovic, Velibor; Nikolic, Milica; Milosevic, Zarko; Saveljic, Igor; Nikolic, Dalibor; Radovic, Milos; Filipović, Nenad

    2015-12-01

    Cochlea is important part of the hearing system, and thanks to special structure converts external sound waves into neural impulses which go to the brain. Shape of the cochlea is like snail, so geometry of the cochlea model is complex. The simplified cochlea coiled model was developed using finite element method inside SIFEM FP7 project. Software application is created on the way that user can prescribe set of the parameters for spiral cochlea, as well as material properties and boundary conditions to the model. Several mathematical models were tested. The acoustic wave equation for describing fluid in the cochlea chambers - scala vestibuli and scala timpani, and Newtonian dynamics for describing vibrations of the basilar membrane are used. The mechanical behavior of the coiled cochlea was analyzed and the third chamber, scala media, was not modeled because it does not have a significant impact on the mechanical vibrations of the basilar membrane. The obtained results are in good agreement with experimental measurements. Future work is needed for more realistic geometry model. Coiled model of the cochlea was created and results are compared with initial simplified coiled model of the cochlea.

  12. ACIR: automatic cochlea image registration

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    Al-Dhamari, Ibraheem; Bauer, Sabine; Paulus, Dietrich; Lissek, Friedrich; Jacob, Roland

    2017-02-01

    Efficient Cochlear Implant (CI) surgery requires prior knowledge of the cochlea's size and its characteristics. This information helps to select suitable implants for different patients. To get these measurements, a segmentation method of cochlea medical images is needed. An important pre-processing step for good cochlea segmentation involves efficient image registration. The cochlea's small size and complex structure, in addition to the different resolutions and head positions during imaging, reveals a big challenge for the automated registration of the different image modalities. In this paper, an Automatic Cochlea Image Registration (ACIR) method for multi- modal human cochlea images is proposed. This method is based on using small areas that have clear structures from both input images instead of registering the complete image. It uses the Adaptive Stochastic Gradient Descent Optimizer (ASGD) and Mattes's Mutual Information metric (MMI) to estimate 3D rigid transform parameters. The use of state of the art medical image registration optimizers published over the last two years are studied and compared quantitatively using the standard Dice Similarity Coefficient (DSC). ACIR requires only 4.86 seconds on average to align cochlea images automatically and to put all the modalities in the same spatial locations without human interference. The source code is based on the tool elastix and is provided for free as a 3D Slicer plugin. Another contribution of this work is a proposed public cochlea standard dataset which can be downloaded for free from a public XNAT server.

  13. Sensory hair cell death and regeneration in fishes

    Directory of Open Access Journals (Sweden)

    Jerry D. Monroe

    2015-04-01

    Full Text Available Sensory hair cells are specialized mechanotransductive receptors required for hearing and vestibular function. Loss of hair cells in humans and other mammals is permanent and causes reduced hearing and balance. In the early 1980’s, it was shown that hair cells continue to be added to the inner ear sensory epithelia in cartilaginous and bony fishes. Soon thereafter, hair cell regeneration was documented in the chick cochlea following acoustic trauma. Since then, research using chick and other avian models has led to great insights into hair cell death and regeneration. However, with the rise of the zebrafish as a model organism for studying disease and developmental processes, there has been an increased interest in studying sensory hair cell death and regeneration in its lateral line and inner ears. Advances derived from studies in zebrafish and other fish species include understanding the effect of ototoxins on hair cells and finding otoprotectants to mitigate ototoxin damage, the role of cellular proliferation versus direct transdifferentiation during hair cell regeneration, and elucidating cellular pathways involved in the regeneration process. This review will summarize research on hair cell death and regeneration using fish models, indicate the potential strengths and weaknesses of these models, and discuss several emerging areas of future studies.

  14. Response of avian bark foragers and cavity nesters to regeneration treatments in the oak-hickory forest of Northern Alabama

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    Wang Yong; Callie Jo Schweitzer; Adrian A. Lesak

    2006-01-01

    We examined bark-foraging and cavity-nesting birds’ use of upland hardwood habitat altered through a shelterwood regeneration experiment on the mid-Cumberland Plateau of northern Alabama. The five regeneration treatments were 0, 25, 50, 75, and 100 percent basal area retention. The 75 percent retention treatment was accomplished by stem-injecting herbicide into mostly...

  15. A Protocol for Decellularizing Mouse Cochleae for Inner Ear Tissue Engineering.

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    Neal, Christopher A; Nelson-Brantley, Jennifer G; Detamore, Michael S; Staecker, Hinrich; Mellott, Adam J

    2018-01-01

    In mammals, mechanosensory hair cells that facilitate hearing lack the ability to regenerate, which has limited treatments for hearing loss. Current regenerative medicine strategies have focused on transplanting stem cells or genetic manipulation of surrounding support cells in the inner ear to encourage replacement of damaged stem cells to correct hearing loss. Yet, the extracellular matrix (ECM) may play a vital role in inducing and maintaining function of hair cells, and has not been well investigated. Using the cochlear ECM as a scaffold to grow adult stem cells may provide unique insights into how the composition and architecture of the extracellular environment aids cells in sustaining hearing function. Here we present a method for isolating and decellularizing cochleae from mice to use as scaffolds accepting perfused adult stem cells. In the current protocol, cochleae are isolated from euthanized mice, decellularized, and decalcified. Afterward, human Wharton's jelly cells (hWJCs) that were isolated from the umbilical cord were carefully perfused into each cochlea. The cochleae were used as bioreactors, and cells were cultured for 30 days before undergoing processing for analysis. Decellularized cochleae retained identifiable extracellular structures, but did not reveal the presence of cells or noticeable fragments of DNA. Cells perfused into the cochlea invaded most of the interior and exterior of the cochlea and grew without incident over a duration of 30 days. Thus, the current method can be used to study how cochlear ECM affects cell development and behavior.

  16. Avian dark cells

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    Hara, J.; Plymale, D. R.; Shepard, D. L.; Hara, H.; Garry, Robert F.; Yoshihara, T.; Zenner, Hans-Peter; Bolton, M.; Kalkeri, R.; Fermin, Cesar D.

    2002-01-01

    Dark cells (DCs) of mammalian and non-mammalian species help to maintain the homeostasis of the inner ear fluids in vivo. Although the avian cochlea is straight and the mammalian cochlea is coiled, no significant difference in the morphology and/or function of mammalian and avian DCs has been reported. The mammalian equivalent of avian DCs are marginal cells and are located in the stria vascularis along a bony sheet. Avian DCs hang free from the tegmentum vasculosum (TV) of the avian lagena between the perilymph and endolymph. Frame averaging was used to image the fluorescence emitted by several fluorochromes applied to freshly isolated dark cells (iDCs) from chickens (Gallus domesticus) inner ears. The viability of iDCs was monitored via trypan blue exclusion at each isolation step. Sodium Green, BCECF-AM, Rhodamine 123 and 9-anthroyl ouabain molecules were used to test iDC function. These fluorochromes label iDCs ionic transmembrane trafficking function, membrane electrogenic potentials and Na+/K+ ATPase pump's activity. Na+/K+ ATPase pump sites, were also evaluated by the p-nitrophenyl phosphatase reaction. These results suggest that iDCs remain viable for several hours after isolation without special culturing requirements and that the number and functional activity of Na+/K+ ATPase pumps in the iDCs were indistinguishable from in vivo DCs. Primary cultures of freshly iDCs were successfully maintained for 28 days in plastic dishes with RPMI 1640 culture medium. The preparation of iDCs overcomes the difficulty of DCs accessability in vivo and the unavoidable contamination that rupturing the inner ear microenvironments induces.

  17. Generation of induced neurons by direct reprogramming in the mammalian cochlea.

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    Nishimura, K; Weichert, R M; Liu, W; Davis, R L; Dabdoub, A

    2014-09-05

    Primary auditory neurons (ANs) in the mammalian cochlea play a critical role in hearing as they transmit auditory information in the form of electrical signals from mechanosensory cochlear hair cells in the inner ear to the brainstem. Their progressive degeneration is associated with disease conditions, excessive noise exposure and aging. Replacement of ANs, which lack the ability to regenerate spontaneously, would have a significant impact on research and advancement in cochlear implants in addition to the amelioration of hearing impairment. The aim of this study was to induce a neuronal phenotype in endogenous non-neural cells in the cochlea, which is the essential organ of hearing. Overexpression of a neurogenic basic helix-loop-helix transcription factor, Ascl1, in the cochlear non-sensory epithelial cells induced neurons at high efficiency at embryonic, postnatal and juvenile stages. Moreover, induced neurons showed typical properties of neuron morphology, gene expression and electrophysiology. Our data indicate that Ascl1 alone or Ascl1 and NeuroD1 is sufficient to reprogram cochlear non-sensory epithelial cells into functional neurons. Generation of neurons from non-neural cells in the cochlea is an important step for the regeneration of ANs in the mature mammalian cochlea. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  18. Development of the mouse cochlea database (MCD).

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    Santi, Peter A; Rapson, Ian; Voie, Arne

    2008-09-01

    The mouse cochlea database (MCD) provides an interactive, image database of the mouse cochlea for learning its anatomy and data mining of its resources. The MCD website is hosted on a centrally maintained, high-speed server at the following URL: (http://mousecochlea.umn.edu). The MCD contains two types of image resources, serial 2D image stacks and 3D reconstructions of cochlear structures. Complete image stacks of the cochlea from two different mouse strains were obtained using orthogonal plane fluorescence optical microscopy (OPFOS). 2D images of the cochlea are presented on the MCD website as: viewable images within a stack, 2D atlas of the cochlea, orthogonal sections, and direct volume renderings combined with isosurface reconstructions. In order to assess cochlear structures quantitatively, "true" cross-sections of the scala media along the length of the basilar membrane were generated by virtual resectioning of a cochlea orthogonal to a cochlear structure, such as the centroid of the basilar membrane or the scala media. 3D images are presented on the MCD website as: direct volume renderings, movies, interactive QuickTime VRs, flythrough, and isosurface 3D reconstructions of different cochlear structures. 3D computer models can also be used for solid model fabrication by rapid prototyping and models from different cochleas can be combined to produce an average 3D model. The MCD is the first comprehensive image resource on the mouse cochlea and is a new paradigm for understanding the anatomy of the cochlea, and establishing morphometric parameters of cochlear structures in normal and mutant mice.

  19. Avian influenza

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    Bird flu; H5N1; H5N2; H5N8; H7N9; Avian influenza A (HPAI) H5 ... The first avian influenza in humans was reported in Hong Kong in 1997. It was called avian influenza (H5N1). The outbreak was linked ...

  20. Unpartitioned versus incompletely partitioned cochleae: radiologic differentiation.

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    Sennaroglu, Levent; Saatci, Isil

    2004-07-01

    In the process of evaluating our patients, we realized that the term "Mondini deformity" was being used to describe two different types of incomplete partition of the cochlea. THE First one consisted of an unpartitioned, completely empty cochlea where the interscalar septum and entire modiolus were absent, giving the cochlea a cystic appearance; a grossly dilated vestibule accompanied this lesion. The second pathology fitted the classic description of Mondini deformity, consisting of a normal basal turn and cystic apex (where the middle and apical turns form a cystic cavity), dilated vestibule, and enlarged vestibular aqueduct. This study was planned to investigate the differences between the two types of incomplete partition for inner ear malformations based on radiologic features. We conducted a retrospective review of temporal bone computed tomography (CT) findings. The subjects were 18 patients with profound bilateral sensorineural hearing loss who had high-resolution CT with contiguous 1-mm thick images obtained through the petrous bone in axial sections. The CT results were reviewed as incomplete partition type I (IP-I) and type II (IP-II). Incomplete partition type I (unpartitioned cochlea, cystic cochleovestibular malformation) is defined as a malformation in which the cochlea lacks the entire modiolus and interscalar septa, resulting in a cystic appearance and there is an accompanying grossly dilated vestibule. In incomplete partition type II (incompletely partitioned cochlea, the Mondini deformity), there is a cochlea comprised of a normal basal turn and cystic apex accompanied by a minimally dilated vestibule and enlarged vestibular aqueduct (VA). Measurements involving the cochlea, vestibule, vestibular aqueduct, and internal auditory canal (IAC) were done to determine the characteristic features of these pathologies. : Thirteen ears had IP-I and 18 ears had IP-II anomaly. The size of the cochleae in both anomalies showed no significant difference from

  1. The innervation of the bat cochlea

    NARCIS (Netherlands)

    Firbas, Wilhelm

    1970-01-01

    For different species of bats, fixed in 5 % formaldehyd, an estimation of the number of neurons in the spiral ganglion was made. The cochleae were decalcified in EDTA and embedded in paraffin. The complete series of sections were stained with hematoxylin. On the sections through the ganglion, the

  2. Optical coherence tomography of the rat cochlea

    NARCIS (Netherlands)

    Wong, B. J. F.; de Boer, JF; Park, B.H.; Chen, ZP; Nelson, JS

    2000-01-01

    Optical coherence tomography (OCT) was used to image the internal structure of a rat cochlea (ex vivo). Immediately following sacrifice, the temporal bone of a Sprague-Dawley rat was harvested. Axial OCT cross sectional images lover regions of interest, 1x1 mm-2x8 mm) were obtained with a spatial

  3. Potassium recycling pathways in the human cochlea.

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    Weber, P C; Cunningham, C D; Schulte, B A

    2001-07-01

    Potential pathways for recycling potassium (K+) used in the maintenance of inner ear electrochemical gradients have been elucidated in animal models. However, little is known about K+ transport in the human cochlea. This study was designed to characterize putative K+ recycling pathways in the human ear and to determine whether observations from animal models can be extrapolated to humans. A prospective laboratory study using an immunohistochemical approach to analyze the distribution of key ion transport mediators in the human cochlea. Human temporal bones were fixed in situ within 1 to 6 hours of death and subsequently harvested at autopsy. Decalcification was accomplished with the aid of microwaving. Immunohistochemical staining was then performed to define the presence and cell type-specific distribution of Na,K-ATPase, sodium-potassium-chloride cotransporter (NKCC), and carbonic anhydrase (CA) in the inner ear. Staining patterns visualized in the human cochlea closely paralleled those seen in other species. Anti-Na,K-ATPase stained strongly the basolateral plasma membrane of strial marginal cells and nerve endings underlying hair cells. This antibody also localized Na,K-ATPase to type II, type IV, and type V fibrocytes in the spiral ligament and in limbal fibrocytes. NKCC was present in the basolateral membrane of strial marginal cells as well as in type II, type V, and limbal fibrocytes. Immunoreactive carbonic anhydrase was present in type I and type III fibrocytes and in epithelial cells lining Reissner's membrane and the spiral prominence. The distribution of several major ion transport proteins in the human cochlea is similar but not identical to that described in various rodent models. These results support the presence of a complex system for recycling and regulating K+ homeostasis in the human cochlea, similar to that described in other mammalian species.

  4. Avian Metapneumoviruses

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    Avian metapneumovirus (aMPV) is an economically important virus that is the primary causal agent of turkey rhinotracheitis (TRT), also known as avian rhinotracheitis (ART). The virus causes an acute highly contagious infection of the upper respiratory tract in turkeys and was first isolated from tur...

  5. An FPGA-Based Electronic Cochlea

    Directory of Open Access Journals (Sweden)

    M. P. Leong

    2003-06-01

    Full Text Available A module generator which can produce an FPGA-based implementation of an electronic cochlea filter with arbitrary precision is presented. Although hardware implementations of electronic cochlea models have traditionally used analog VLSI as the implementation medium due to their small area, high speed, and low power consumption, FPGA-based implementations offer shorter design times, improved dynamic range, higher accuracy, and a simpler computer interface. The tool presented takes filter coefficients as input and produces a synthesizable VHDL description of an application-optimized design as output. Furthermore, the tool can use simulation test vectors in order to determine the appropriate scaling of the fixed point precision parameters for each filter. The resulting model can be used as an accelerator for research in audition or as the front-end for embedded auditory signal processing systems. The application of this module generator to a real-time cochleagram display is also presented.

  6. Avian Biotechnology.

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    Nakamura, Yoshiaki

    2017-01-01

    Primordial germ cells (PGCs) generate new individuals through differentiation, maturation and fertilization. This means that the manipulation of PGCs is directly linked to the manipulation of individuals, making PGCs attractive target cells in the animal biotechnology field. A unique biological property of avian PGCs is that they circulate temporarily in the vasculature during early development, and this allows us to access and manipulate avian germ lines. Following the development of a technique for transplantation, PGCs have become central to avian biotechnology, in contrast to the use of embryo manipulation and subsequent transfer to foster mothers, as in mammalian biotechnology. Today, avian PGC transplantation combined with recent advanced manipulation techniques, including cell purification, cryopreservation, depletion, and long-term culture in vitro, have enabled the establishment of genetically modified poultry lines and ex-situ conservation of poultry genetic resources. This chapter introduces the principles, history, and procedures of producing avian germline chimeras by transplantation of PGCs, and the current status of avian germline modification as well as germplasm cryopreservation. Other fundamental avian reproductive technologies are described, including artificial insemination and embryo culture, and perspectives of industrial applications in agriculture and pharmacy are considered, including poultry productivity improvement, egg modification, disease resistance impairment and poultry gene "pharming" as well as gene banking.

  7. Avian Wings

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    Liu, Tianshu; Kuykendoll, K.; Rhew, R.; Jones, S.

    2004-01-01

    This paper describes the avian wing geometry (Seagull, Merganser, Teal and Owl) extracted from non-contact surface measurements using a three-dimensional laser scanner. The geometric quantities, including the camber line and thickness distribution of airfoil, wing planform, chord distribution, and twist distribution, are given in convenient analytical expressions. Thus, the avian wing surfaces can be generated and the wing kinematics can be simulated. The aerodynamic characteristics of avian airfoils in steady inviscid flows are briefly discussed. The avian wing kinematics is recovered from videos of three level-flying birds (Crane, Seagull and Goose) based on a two-jointed arm model. A flapping seagull wing in the 3D physical space is re-constructed from the extracted wing geometry and kinematics.

  8. Avian Flu

    International Nuclear Information System (INIS)

    Eckburg, Paul

    2006-01-01

    Since 2003, a severe form of H5N1 avian influenza has rapidly spread throughout Asia and Europe, infecting over 200 humans in 10 countries. The spread of H5N1 virus from person-to-person has been rare, thus preventing the emergence of a widespread pandemic. However, this ongoing epidemic continues to pose an important public health threat. Avian flu and its pandemic potential in humans will be discussed.

  9. Hedgehog Signaling Promotes the Proliferation and Subsequent Hair Cell Formation of Progenitor Cells in the Neonatal Mouse Cochlea

    Science.gov (United States)

    Chen, Yan; Lu, Xiaoling; Guo, Luo; Ni, Wenli; Zhang, Yanping; Zhao, Liping; Wu, Lingjie; Sun, Shan; Zhang, Shasha; Tang, Mingliang; Li, Wenyan; Chai, Renjie; Li, Huawei

    2017-01-01

    Hair cell (HC) loss is the major cause of permanent sensorineural hearing loss in mammals. Unlike lower vertebrates, mammalian cochlear HCs cannot regenerate spontaneously after damage, although the vestibular system does maintain limited HC regeneration capacity. Thus HC regeneration from the damaged sensory epithelium has been one of the main areas of research in the field of hearing restoration. Hedgehog signaling plays important roles during the embryonic development of the inner ear, and it is involved in progenitor cell proliferation and differentiation as well as the cell fate decision. In this study, we show that recombinant Sonic Hedgehog (Shh) protein effectively promotes sphere formation, proliferation, and differentiation of Lgr5+ progenitor cells isolated from the neonatal mouse cochlea. To further explore this, we determined the effect of Hedgehog signaling on cell proliferation and HC regeneration in cultured cochlear explant from transgenic R26-SmoM2 mice that constitutively activate Hedgehog signaling in the supporting cells of the cochlea. Without neomycin treatment, up-regulation of Hedgehog signaling did not significantly promote cell proliferation or new HC formation. However, after injury to the sensory epithelium by neomycin treatment, the over-activation of Hedgehog signaling led to significant supporting cell proliferation and HC regeneration in the cochlear epithelium explants. RNA sequencing and real-time PCR were used to compare the transcripts of the cochleae from control mice and R26-SmoM2 mice, and multiple genes involved in the proliferation and differentiation processes were identified. This study has important implications for the treatment of sensorineural hearing loss by manipulating the Hedgehog signaling pathway. PMID:29311816

  10. Hedgehog Signaling Promotes the Proliferation and Subsequent Hair Cell Formation of Progenitor Cells in the Neonatal Mouse Cochlea

    Directory of Open Access Journals (Sweden)

    Yan Chen

    2017-12-01

    Full Text Available Hair cell (HC loss is the major cause of permanent sensorineural hearing loss in mammals. Unlike lower vertebrates, mammalian cochlear HCs cannot regenerate spontaneously after damage, although the vestibular system does maintain limited HC regeneration capacity. Thus HC regeneration from the damaged sensory epithelium has been one of the main areas of research in the field of hearing restoration. Hedgehog signaling plays important roles during the embryonic development of the inner ear, and it is involved in progenitor cell proliferation and differentiation as well as the cell fate decision. In this study, we show that recombinant Sonic Hedgehog (Shh protein effectively promotes sphere formation, proliferation, and differentiation of Lgr5+ progenitor cells isolated from the neonatal mouse cochlea. To further explore this, we determined the effect of Hedgehog signaling on cell proliferation and HC regeneration in cultured cochlear explant from transgenic R26-SmoM2 mice that constitutively activate Hedgehog signaling in the supporting cells of the cochlea. Without neomycin treatment, up-regulation of Hedgehog signaling did not significantly promote cell proliferation or new HC formation. However, after injury to the sensory epithelium by neomycin treatment, the over-activation of Hedgehog signaling led to significant supporting cell proliferation and HC regeneration in the cochlear epithelium explants. RNA sequencing and real-time PCR were used to compare the transcripts of the cochleae from control mice and R26-SmoM2 mice, and multiple genes involved in the proliferation and differentiation processes were identified. This study has important implications for the treatment of sensorineural hearing loss by manipulating the Hedgehog signaling pathway.

  11. Finite element cochlea box model - Mechanical and electrical analysis of the cochlea

    Science.gov (United States)

    Nikolic, Milica; Teal, Paul D.; Isailovic, Velibor; Filipović, Nenad

    2015-12-01

    The primary role of the cochlea is to transform external sound stimuli into mechanical vibrations and then to neural impulses which are sent to the brain. A simplified cochlea box model was developed using the finite element method. Firstly, a mechanical model of the cochlea was analyzed. The box model consists of the basilar membrane and two fluid chambers - the scala vestibuli and scala tympani. The third chamber, the scala media, was neglected in the mechanical analysis. The best agreement with currently available analytical and experimental results was obtained when behavior of the fluid in the chambers was described using the wave acoustic equation and behavior of the basilar membrane was modeled with Newtonian dynamics. The obtained results show good frequency mapping. The second approach was to use an active model of the cochlea in which the Organ of Corti was included. The operation of the Organ of Corti involves the generation of current, caused by mechanical vibration. This current in turn causes a force applied to the basilar membrane, creating in this way an active feedback mechanism. A state space representation of the electro-mechanical model from existing literature was implemented and a first comparison with the finite element method is presented.

  12. Schwannoma in the vestibule and cochlea

    Energy Technology Data Exchange (ETDEWEB)

    Susilawati, S. [Fatmawati Hospital, Jakarta (Indonesia). Department of Ear, Nose and Throat; Adler, J. [Sutherland Imaging Centre, Sydney, NSW (Australia); Fagan, P. [St Vincents Hospital, Darlinghurst, NSW (Australia)

    1997-05-01

    Schwannoma of the vestibule or the cochlea is an unusual lesion. In the past, most examples have been found at autopsy or as unsuspected findings at surgery for vertigo. The symptoms of isolated labyrinthine schwannoma may be indistinguishable from advanced Meniere`s disease. Magnetic resonance imaging has led to pre-operative diagnosis in some cases. Two cases of schwannoma within the labyrinth from a series of 339 symptomatic acoustic tumours, are presented and the imaging findings are discussed. 8 refs., 2 figs.

  13. Junctional E-cadherin/p120-catenin Is Correlated with the Absence of Supporting Cells to Hair Cells Conversion in Postnatal Mice Cochleae.

    Science.gov (United States)

    Luo, Wen-Wei; Wang, Xin-Wei; Ma, Rui; Chi, Fang-Lu; Chen, Ping; Cong, Ning; Gu, Yu-Yan; Ren, Dong-Dong; Yang, Juan-Mei

    2018-01-01

    Notch inhibition is known to generate supernumerary hair cells (HCs) at the expense of supporting cells (SCs) in the mammalian inner ear. However, inhibition of Notch activity becomes progressively less effective at inducing SC-to-HC conversion in the postnatal cochlea and balance organs as the animal ages. It has been suggested that the SC-to-HC conversion capacity is inversely correlated with E-cadherin accumulation in postnatal mammalian utricles. However, whether E-cadherin localization is linked to the SC-to-HC conversion capacity in the mammalian inner ear is poorly understood. In the present study, we treated cochleae from postnatal day 0 (P0) with the Notch signaling inhibitor DAPT and observed apparent SC-to-HC conversion along with E-cadherin/p120ctn disruption in the sensory region. In addition, the SC-to-HC conversion capacity and E-cadherin/p120ctn disorganization were robust in the apex but decreased toward the base. We further demonstrated that the ability to regenerate HCs and the disruption of E-cadherin/p120ctn concomitantly decreased with age and ceased at P7, even after extended DAPT treatments. This timing is consistent with E-cadherin/p120ctn accumulation in the postnatal cochleae. These results suggest that the decreasing capacity of SCs to transdifferentiate into HCs correlates with E-cadherin/p120ctn localization in the postnatal cochleae, which might account for the absence of SC-to-HC conversion in the mammalian cochlea.

  14. Cochlea and other spiral forms in nature and art.

    Science.gov (United States)

    Marinković, Slobodan; Stanković, Predrag; Štrbac, Mile; Tomić, Irina; Ćetković, Mila

    2012-01-01

    The original appearance of the cochlea and the specific shape of a spiral are interesting for both the scientists and artists. Yet, a correlation between the cochlea and the spiral forms in nature and art has been very rarely mentioned. The aim of this study was to investigate the possible correlation between the cochlea and the other spiral objects in nature, as well as the artistic presentation of the spiral forms. We explored data related to many natural objects and examined 13,625 artworks created by 2049 artists. We also dissected 2 human cochleas and prepared histologic slices of a rat cochlea. The cochlea is a spiral, cone-shaped osseous structure that resembles certain other spiral forms in nature. It was noticed that parts of some plants are arranged in a spiral manner, often according to Fibonacci numbers. Certain animals, their parts, or their products also represent various types of spirals. Many of them, including the cochlea, belong to the logarithmic type. Nature created spiral forms in the living world to pack a larger number of structures in a limited space and also to improve their function. Because the cochlea and other spiral forms have a certain aesthetic value, many artists presented them in their works of art. There is a mathematical and geometric correlation between the cochlea and natural spiral objects, and the same functional reason for their formation. The artists' imagery added a new aspect to those domains. Obviously, the creativity of nature and Homo sapiens has no limits--like the infinite distal part of the spiral. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Characterization of the Transcriptomes of Lgr5+ Hair Cell Progenitors and Lgr5- Supporting Cells in the Mouse Cochlea.

    Science.gov (United States)

    Cheng, Cheng; Guo, Luo; Lu, Ling; Xu, Xiaochen; Zhang, ShaSha; Gao, Junyan; Waqas, Muhammad; Zhu, Chengwen; Chen, Yan; Zhang, Xiaoli; Xuan, Chuanying; Gao, Xia; Tang, Mingliang; Chen, Fangyi; Shi, Haibo; Li, Huawei; Chai, Renjie

    2017-01-01

    Cochlear supporting cells (SCs) have been shown to be a promising resource for hair cell (HC) regeneration in the neonatal mouse cochlea. Previous studies have reported that Lgr5+ SCs can regenerate HCs both in vitro and in vivo and thus are considered to be inner ear progenitor cells. Lgr5+ progenitors are able to regenerate more HCs than Lgr5- SCs, and it is important to understand the mechanism behind the proliferation and HC regeneration of these progenitors. Here, we isolated Lgr5+ progenitors and Lgr5- SCs from Lgr5-EGFP-CreERT2/Sox2-CreERT2/Rosa26-tdTomato mice via flow cytometry. As expected, we found that Lgr5+ progenitors had significantly higher proliferation and HC regeneration ability than Lgr5- SCs. Next, we performed RNA-Seq to determine the gene expression profiles of Lgr5+ progenitors and Lgr5- SCs. We analyzed the genes that were enriched and differentially expressed in Lgr5+ progenitors and Lgr5- SCs, and we found 8 cell cycle genes, 9 transcription factors, and 24 cell signaling pathway genes that were uniquely expressed in one population but not the other. Last, we made a protein-protein interaction network to further analyze the role of these differentially expressed genes. In conclusion, we present a set of genes that might regulate the proliferation and HC regeneration ability of Lgr5+ progenitors, and these might serve as potential new therapeutic targets for HC regeneration.

  16. Characterization of the Transcriptomes of Lgr5+ Hair Cell Progenitors and Lgr5- Supporting Cells in the Mouse Cochlea

    Directory of Open Access Journals (Sweden)

    Haibo Shi

    2017-04-01

    Full Text Available Cochlear supporting cells (SCs have been shown to be a promising resource for hair cell (HC regeneration in the neonatal mouse cochlea. Previous studies have reported that Lgr5+ SCs can regenerate HCs both in vitro and in vivo and thus are considered to be inner ear progenitor cells. Lgr5+ progenitors are able to regenerate more HCs than Lgr5- SCs, and it is important to understand the mechanism behind the proliferation and HC regeneration of these progenitors. Here, we isolated Lgr5+ progenitors and Lgr5- SCs from Lgr5-EGFP-CreERT2/Sox2-CreERT2/Rosa26-tdTomato mice via flow cytometry. As expected, we found that Lgr5+ progenitors had significantly higher proliferation and HC regeneration ability than Lgr5- SCs. Next, we performed RNA-Seq to determine the gene expression profiles of Lgr5+ progenitors and Lgr5- SCs. We analyzed the genes that were enriched and differentially expressed in Lgr5+ progenitors and Lgr5- SCs, and we found 8 cell cycle genes, 9 transcription factors, and 24 cell signaling pathway genes that were uniquely expressed in one population but not the other. Last, we made a protein–protein interaction network to further analyze the role of these differentially expressed genes. In conclusion, we present a set of genes that might regulate the proliferation and HC regeneration ability of Lgr5+ progenitors, and these might serve as potential new therapeutic targets for HC regeneration.

  17. Characterization of the Transcriptomes of Lgr5+ Hair Cell Progenitors and Lgr5- Supporting Cells in the Mouse Cochlea

    Science.gov (United States)

    Cheng, Cheng; Guo, Luo; Lu, Ling; Xu, Xiaochen; Zhang, ShaSha; Gao, Junyan; Waqas, Muhammad; Zhu, Chengwen; Chen, Yan; Zhang, Xiaoli; Xuan, Chuanying; Gao, Xia; Tang, Mingliang; Chen, Fangyi; Shi, Haibo; Li, Huawei; Chai, Renjie

    2017-01-01

    Cochlear supporting cells (SCs) have been shown to be a promising resource for hair cell (HC) regeneration in the neonatal mouse cochlea. Previous studies have reported that Lgr5+ SCs can regenerate HCs both in vitro and in vivo and thus are considered to be inner ear progenitor cells. Lgr5+ progenitors are able to regenerate more HCs than Lgr5- SCs, and it is important to understand the mechanism behind the proliferation and HC regeneration of these progenitors. Here, we isolated Lgr5+ progenitors and Lgr5- SCs from Lgr5-EGFP-CreERT2/Sox2-CreERT2/Rosa26-tdTomato mice via flow cytometry. As expected, we found that Lgr5+ progenitors had significantly higher proliferation and HC regeneration ability than Lgr5- SCs. Next, we performed RNA-Seq to determine the gene expression profiles of Lgr5+ progenitors and Lgr5- SCs. We analyzed the genes that were enriched and differentially expressed in Lgr5+ progenitors and Lgr5- SCs, and we found 8 cell cycle genes, 9 transcription factors, and 24 cell signaling pathway genes that were uniquely expressed in one population but not the other. Last, we made a protein–protein interaction network to further analyze the role of these differentially expressed genes. In conclusion, we present a set of genes that might regulate the proliferation and HC regeneration ability of Lgr5+ progenitors, and these might serve as potential new therapeutic targets for HC regeneration. PMID:28491023

  18. Avian cholera

    Science.gov (United States)

    Friend, Milton

    1999-01-01

    Avian cholera is a contagious disease resulting from infection by the bacterium Pasteurella multocida. Several subspecies of bacteria have been proposed for P. multocida, and at least 16 different P. multocida serotypes or characteristics of antigens in bacterial cells that differentiate bacterial variants from each other have been recognized. The serotypes are further differentiated by other methods, including DNA fingerprinting. These evaluations are useful for studying the ecology of avian cholera (Fig. 7.1), because different serotypes are generally found in poultry and free-ranging migratory birds. These evaluations also show that different P. multocida serotypes are found in wild birds in the eastern United States than those that are found in the birds in the rest of the Nation (Fig. 7.2).

  19. Avian Influenza.

    Science.gov (United States)

    Zeitlin, Gary Adam; Maslow, Melanie Jane

    2005-05-01

    The current epidemic of H5N1 highly pathogenic avian influenza in Southeast Asia raises serious concerns that genetic reassortment will result in the next influenza pandemic. There have been 164 confirmed cases of human infection with avian influenza since 1996. In 2004, there were 45 cases of human H5N1 in Vietnam and Thailand, with a mortality rate more than 70%. In addition to the potential public health hazard, the current zoonotic epidemic has caused severe economic losses. Efforts must be concentrated on early detection of bird outbreaks with aggressive culling, quarantining, and disinfection. To prepare for and prevent an increase in human cases, it is essential to improve detection methods and stockpile effective antivirals. Novel therapeutic modalities, including short-interfering RNAs and new vaccine strategies that use plasmid-based genetic systems, offer promise should a pandemic occur.

  20. Avian influenza

    DEFF Research Database (Denmark)

    EFSA Panel on Animal Health and Welfare; More, Simon; Bicout, Dominique

    2017-01-01

    Previous introductions of highly pathogenic avian influenza virus (HPAIV) to the EU were most likely via migratory wild birds. A mathematical model has been developed which indicated that virus amplification and spread may take place when wild bird populations of sufficient size within EU become ...... of implementing specific biosecurity measures on reducing the probability of AIV entering into a poultry holding. Human diligence is pivotal to select, implement and maintain specific, effective biosecurity measures....

  1. Avian And Other Zoonotic Influenza

    Science.gov (United States)

    ... of Avian Influenza A(H5N1) Avian influenza: guidelines. recommendations, descriptions Global Influenza and Surveillance Response System (GISRS) Food safety authorities network OIE Avian Influenza ...

  2. Avian pox

    Science.gov (United States)

    Hansen, W.

    1999-01-01

    Avian pox is the common name for a mild-to-severe, slowdeveloping disease of birds that is caused by a large virus belonging to the avipoxvirus group, a subgroup of poxviruses. This group contains several similar virus strains; some strains have the ability to infect several groups or species of birds but others appear to be species-specific. Mosquitoes are common mechanical vectors or transmitters of this disease. Avian pox is transmitted when a mosquito feeds on an infected bird that has viremia or pox virus circulating in its blood, or when a mosquito feeds on virus-laden secretions seeping from a pox lesion and then feeds on another bird that is susceptible to that strain of virus. Contact with surfaces or exposure to air-borne particles contaminated with poxvirus can also result in infections when virus enters the body through abraded skin or the conjunctiva or the mucous membrane lining that covers the front part of the eyeball and inner surfaces of the eyelids of the eye.

  3. The shortened cochlea: its classification and histopathologic features.

    Science.gov (United States)

    Zheng, Yiqing; Schachern, Patricia A; Cureoglu, Sebahattin; Mutlu, Cemil; Dijalilian, Hamid; Paparella, Michael M

    2002-03-15

    The term 'Mondini dysplasia' has been used to describe virtually any congenital abnormality of the osseous labyrinth resulting in confusion and seemingly contradictory observations and conclusions about this type of deformity. The purpose of this study is to histopathologically classify and describe temporal bones whose cochleas have less than 2.5 turns. Of the 1800 temporal bones in our collection, 21 from 12 cases were found to have cochleas with less than 2.5 cochlear turns. Ages ranged from stillborn to 50 years. Temporal bones were harvested at autopsy, processed and embedded in celloidin. Sections were cut at a thickness of 20 microm and every 10th section stained with hematoxylin-eosin and examined using light microscopy. The number of turns, length of cochlea, integrity of cochlear base, length of modiolus, abnormalities of the semicircular canals and vestibule, enlargement of the vestibular aqueduct and middle ears were documented. Twenty-one temporal bones from age-matched patients without cochlear deformities were used as controls for modiolar length measurements. Malformation of the shortened cochlea was histopathologically classified into three groups as follows: (1) Common cavity, cochlear dysplasia (one ear)--severe dysplasia of the cochlea without a complete basal turn; (2) Mondini dysplasia (11 ears)--1.5 cochlear turns, a complete basal turn, an incomplete or absent interscalar septum and a complete bone at the base of the modiolus; and (3) Mondini-like dysplasia type A (five ears)--2 turns to the cochlea including a complete basal turn and complete bone at the base of the modiolus; and type B (four ears)--1.5-2 turns to the cochlea, hypoplasia of or a missing bone at the base of the modiolus (either with or without a communication between the internal auditory canal and the cochlea) and a complete basal turn. The range of congenital malformations in short cochlea is highly variable. Fundamental to the accurate evaluation of a labyrinthine anomaly

  4. Cryogenic regenerators

    International Nuclear Information System (INIS)

    Kush, P.; Joshi, S.C.; Thirumaleshwar, M.

    1986-01-01

    Importance of regenerators in cryogenic refrigerators is highlighted. Design aspects of regenerator are reviewed and the factors involved in the selection of regenerator material are enumerated. Various methods used to calculate the heat transfer coefficient and regenerator effectiveness are mentioned. Variation of effectiveness with various parameters is calculated by a computer programme using the ideal, Ackermann and Tipler formulae. Results are presented in graphical form. Listing of the computer programme is given in the Appendix. (author)

  5. Avian respiratory system disorders

    Science.gov (United States)

    Olsen, Glenn H.

    1989-01-01

    Diagnosing and treating respiratory diseases in avian species requires a basic knowledge about the anatomy and physiology of this system in birds. Differences between mammalian and avian respiratory system function, diagnosis, and treatment are highlighted.

  6. Avian Influenza (Bird Flu)

    Science.gov (United States)

    ... type="submit" value="Submit" /> Archived Flu Emails Influenza Types Seasonal Avian Swine Variant Pandemic Other Information on Avian Influenza Language: English (US) Español Recommend on Facebook Tweet ...

  7. Junctional E-cadherin/p120-catenin Is Correlated with the Absence of Supporting Cells to Hair Cells Conversion in Postnatal Mice Cochleae

    Directory of Open Access Journals (Sweden)

    Wen-wei Luo

    2018-02-01

    Full Text Available Notch inhibition is known to generate supernumerary hair cells (HCs at the expense of supporting cells (SCs in the mammalian inner ear. However, inhibition of Notch activity becomes progressively less effective at inducing SC-to-HC conversion in the postnatal cochlea and balance organs as the animal ages. It has been suggested that the SC-to-HC conversion capacity is inversely correlated with E-cadherin accumulation in postnatal mammalian utricles. However, whether E-cadherin localization is linked to the SC-to-HC conversion capacity in the mammalian inner ear is poorly understood. In the present study, we treated cochleae from postnatal day 0 (P0 with the Notch signaling inhibitor DAPT and observed apparent SC-to-HC conversion along with E-cadherin/p120ctn disruption in the sensory region. In addition, the SC-to-HC conversion capacity and E-cadherin/p120ctn disorganization were robust in the apex but decreased toward the base. We further demonstrated that the ability to regenerate HCs and the disruption of E-cadherin/p120ctn concomitantly decreased with age and ceased at P7, even after extended DAPT treatments. This timing is consistent with E-cadherin/p120ctn accumulation in the postnatal cochleae. These results suggest that the decreasing capacity of SCs to transdifferentiate into HCs correlates with E-cadherin/p120ctn localization in the postnatal cochleae, which might account for the absence of SC-to-HC conversion in the mammalian cochlea.

  8. Avian influenza virus

    Science.gov (United States)

    Avian influenza virus (AIV) is type A influenza that is adapted to avian host species. Although the virus can be isolated from numerous avian species, the natural host reservoir species are dabbling ducks, shorebirds and gulls. Domestic poultry species (poultry being defined as birds that are rais...

  9. Cochlea Segmentation using Iterated Random Walks with Shape Prior

    DEFF Research Database (Denmark)

    Ruiz Pujadas, Esmeralda; Kjer, Hans Martin; Vera, Sergio

    2016-01-01

    Cochlear implants can restore hearing to deaf or partially deaf patients. In order to plan the intervention, a model from high resolution μCT images is to be built from accurate cochlea segmentations and then, adapted to a patient-specific model. Thus, a precise segmentation is required to build...

  10. Regeneration and replacement in the vertebrate inner ear.

    Science.gov (United States)

    Matsui, Jonathan I; Parker, Mark A; Ryals, Brenda M; Cotanche, Douglas A

    2005-10-01

    Deafness affects more than 40 million people in the UK and the USA, and many more world-wide. The primary cause of hearing loss is damage to or death of the sensory receptor cells in the inner ear, the hair cells. Birds can readily regenerate their cochlear hair cells but the mammalian cochlea has shown no ability to regenerate after damage. Current research efforts are focusing on gene manipulation, gene therapy and stem cell transplantation for repairing or replacing damaged mammalian cochlear hair cells, which could lead to therapies for treating deafness in humans.

  11. Vegetative regeneration

    Science.gov (United States)

    George A. Schier; John R. Jones; Robert P. Winokur

    1985-01-01

    Aspen is noted for its ability to regenerate vegetatively by adventitious shoots or suckers that arise on its long lateral roots. It also produces sprouts from stumps and root collars; but they are not common. In a survey of regeneration after clearcutting mature aspen in Utah. Baker (1918b) found that 92% of the shoots originated from roots, 7% from root collars, and...

  12. Liver regeneration

    NARCIS (Netherlands)

    Chamuleau, R. A.; Bosman, D. K.

    1988-01-01

    Despite great advances in analysing hemodynamic, morphological and biochemical changes during the process of liver regeneration, the exact (patho)physiological mechanism is still unknown. A short survey of literature is given of the kinetics of liver regeneration and the significance of different

  13. Inactivation of STAT3 Signaling Impairs Hair Cell Differentiation in the Developing Mouse Cochlea

    Directory of Open Access Journals (Sweden)

    Qianqian Chen

    2017-07-01

    Full Text Available Although STAT3 signaling is demonstrated to regulate sensory cell differentiation and regeneration in the zebrafish, its exact role is still unclear in mammalian cochleae. Here, we report that STAT3 and its activated form are specifically expressed in hair cells during mouse cochlear development. Importantly, conditional cochlear deletion of Stat3 leads to an inhibition on hair cell differentiation in mice in vivo and in vitro. By cell fate analysis, inactivation of STAT3 signaling shifts the cell division modes from asymmetric to symmetric divisions from supporting cells. Moreover, inhibition of Notch signaling stimulates STAT3 phosphorylation, and inactivation of STAT3 signaling attenuates production of supernumerary hair cells induced by a Notch pathway inhibitor. Our findings highlight an important role of the STAT3 signaling during mouse cochlear hair cell differentiation and may have clinical implications for the recovery of hair cell loss-induced hearing impairment.

  14. Bird Flu (Avian Influenza)

    Science.gov (United States)

    Bird flu (avian influenza) Overview Bird flu is caused by a type of influenza virus that rarely infects humans. More than a ... for Disease Control and Prevention estimates that seasonal influenza is responsible for ... heat destroys avian viruses, cooked poultry isn't a health threat. ...

  15. A contrastive analysis of laser heating between the human and guinea pig cochlea by numerical simulations.

    Science.gov (United States)

    Zhang, Kaiyin; Zhang, Yulong; Li, Ji; Wang, Qiuling

    2016-05-23

    The photo-thermal effect has been hypothesised to be one of the most possible biophysical mechanisms for laser-cochlea stimulation. However, there is a lack of studies to date for direct assessing laser heating in humans due to the large body of evidence required to demonstrate safety and efficacy. Instead, the majority focus on animals like the guinea pig, from which a number of valuable results have been gained. However, in light of the increasing need to improve laser safety, it has became necessary to find out whether studies on animals can shed light on safe laser parameters in the human cochlea. Hence, we conducted this contrastive analysis of laser heating between the human and guinea pig cochlea with the aim of assisting further investigations in this field. In this work, a 3D symmetrical model was adopted to simplify the spiraled cochlea. With attention focused on the effect of heat conduction, the time-dependent heat equation was solved using finite element method with the COMSOL Script. In the simulations, cochleae with different sizes and various boundary thermal conditions were utilized. Laser heating in both cochleae has a similar trend. In the first stage, or at the beginning of the laser heating, both cochleae increased their temperatures rapidly. In the second stage in which the laser heating reached a quasi-steady stage, the peak temperatures began to rise slowly as more laser pulses were applied. However, three differences of the laser heating were observed. The first is regarding the temperature rise. The results show that laser heating in guinea pig is higher than that in human under the same laser parameters. The second difference is the fluctuation of temperature rise at the center of the modiolus. There is a larger fluctuation of temperature rise in the guinea pig cochlea, compared with that in the human cochlea. The third one is the time for reaching a steady thermal state. The results show that the guinea pig cochlea takes longer time to

  16. Discussion: Changes in Vocal Production and Auditory Perception after Hair Cell Regeneration.

    Science.gov (United States)

    Ryals, Brenda M.; Dooling, Robert J.

    2000-01-01

    A bird study found that with sufficient time and training after hair cell and hearing loss and hair cell regeneration, the mature avian auditory system can accommodate input from a newly regenerated periphery sufficiently to allow for recognition of previously familiar vocalizations and the learning of new complex acoustic classifications.…

  17. Cell Source and Mechanism of Hair Cell Regeneration in the Neonatal Mouse Cochlea

    Science.gov (United States)

    2015-09-30

    authorship of the paper. The cotTect author list and affiliations appears above. In add ition the Acknowledgements and Author contributions sections should...Mice ofboth genders were used in this study. 1l1e n value throughout the paper reflects the number of animals analyzed per experiment. All animal work...published in Development141, 816-829. Edwin W. Rubel was omi tted fro m the authorship of the paper. The correct author list and affi liations appears

  18. A comprehensive three-dimensional model of the cochlea

    International Nuclear Information System (INIS)

    Givelberg, Edward; Bunn, Julian

    2003-01-01

    The human cochlea is a remarkable device, able to discern extremely small amplitude sound pressure waves, and discriminate between very close frequencies. Simulation of the cochlea is computationally challenging due to its complex geometry, intricate construction and small physical size. We have developed, and are continuing to refine, a detailed three-dimensional computational model based on an accurate cochlear geometry obtained from physical measurements. In the model, the immersed boundary method is used to calculate the fluid-structure interactions produced in response to incoming sound waves. The model includes a detailed and realistic description of the various elastic structures present. In this paper, we describe the computational model and its performance on the latest generation of shared memory servers from Hewlett Packard. Using compiler generated threads and OpenMP directives, we have achieved a high degree of parallelism in the executable, which has made possible several large scale numerical simulation experiments that study the interesting features of the cochlear system. We show several results from these simulations, reproducing some of the basic known characteristics of cochlear mechanics

  19. My Regeneration:

    DEFF Research Database (Denmark)

    Carter, Dale

    2017-01-01

    and cultural referents shows that it offers an index to the album. Using its frontier setting and a variety of sacred and secular myths, symbols and icons, ‘Heroes and Villains,’ like Smile as a whole, offers historically-informed visions of national decline, crisis and regeneration that are at once critical...

  20. Avian Influenza in Birds

    Science.gov (United States)

    ... the United States Department of Agriculture’s Animal and Plant Health Inspection Service . Surveillance for Avian Influenza CDC, ... maintained by: Office of the Associate Director for Communication, Digital Media Branch, Division of Public Affairs Email ...

  1. Dose verification to cochlea during gamma knife radiosurgery of acoustic schwannoma using MOSFET dosimeter.

    Science.gov (United States)

    Sharma, Sunil D; Kumar, Rajesh; Akhilesh, Philomina; Pendse, Anil M; Deshpande, Sudesh; Misra, Basant K

    2012-01-01

    Dose verification to cochlea using metal oxide semiconductor field effect transistor (MOSFET) dosimeter using a specially designed multi slice head and neck phantom during the treatment of acoustic schwannoma by Gamma Knife radiosurgery unit. A multi slice polystyrene head phantom was designed and fabricated for measurement of dose to cochlea during the treatment of the acoustic schwannoma. The phantom has provision to position the MOSFET dosimeters at the desired location precisely. MOSFET dosimeters of 0.2 mm x 0.2 mm x 0.5 μm were used to measure the dose to the cochlea. CT scans of the phantom with MOSFETs in situ were taken along with Leksell frame. The treatment plans of five patients treated earlier for acoustic schwannoma were transferred to the phantom. Dose and coordinates of maximum dose point inside the cochlea were derived. The phantom along with the MOSFET dosimeters was irradiated to deliver the planned treatment and dose received by cochlea were measured. The treatment planning system (TPS) estimated and measured dose to the cochlea were in the range of 7.4 - 8.4 Gy and 7.1 - 8 Gy, respectively. The maximum variation between TPS calculated and measured dose to cochlea was 5%. The measured dose values were found in good agreement with the dose values calculated using the TPS. The MOSFET dosimeter can be a suitable choice for routine dose verification in the Gamma Knife radiosurgery.

  2. Scanning laser optical tomography for in toto imaging of the murine cochlea.

    Directory of Open Access Journals (Sweden)

    Lena Nolte

    Full Text Available The mammalian cochlea is a complex macroscopic structure due to its helical shape and the microscopic arrangements of the individual layers of cells. To improve the outcomes of hearing restoration in deaf patients, it is important to understand the anatomic structure and composition of the cochlea ex vivo. Hitherto, only one histological technique based on confocal laser scanning microscopy and optical clearing has been developed for in toto optical imaging of the murine cochlea. However, with a growing size of the specimen, e.g., human cochlea, this technique reaches its limitations. Here, we demonstrate scanning laser optical tomography (SLOT as a valuable imaging technique to visualize the murine cochlea in toto without any physical slicing. This technique can also be applied in larger specimens up to cm3 such as the human cochlea. Furthermore, immunolabeling allows visualization of inner hair cells (otoferlin or spiral ganglion cells (neurofilament within the whole cochlea. After image reconstruction, the 3D dataset was used for digital segmentation of the labeled region. As a result, quantitative analysis of position, length and curvature of the labeled region was possible. This is of high interest in order to understand the interaction of cochlear implants (CI and cells in more detail.

  3. Periodontal regeneration.

    Science.gov (United States)

    Ivanovski, S

    2009-09-01

    The ultimate goal of periodontal therapy is the regeneration of the tissues destroyed as a result of periodontal disease. Currently, two clinical techniques, based on the principles of "guided tissue regeneration" (GTR) or utilization of the biologically active agent "enamel matrix derivative" (EMD), can be used for the regeneration of intrabony and Class II mandibular furcation periodontal defects. In cases where additional support and space-making requirements are necessary, both of these procedures can be combined with a bone replacement graft. There is no evidence that the combined use of GTR and EMD results in superior clinical results compared to the use of each material in isolation. Great variability in clinical outcomes has been reported in relation to the use of both EMD and GTR, and these procedures can be generally considered to be unpredictable. Careful case selection and treatment planning, including consideration of patient, tooth, site and surgical factors, is required in order to optimize the outcomes of treatment. There are limited data available for the clinical effectiveness of other biologically active molecules, such as growth factors and platelet concentrates, and although promising results have been reported, further clinical trials are required in order to confirm their effectiveness. Current active areas of research are centred on tissue engineering and gene therapy strategies which may result in more predictable regenerative outcomes in the future.

  4. Scala vestibuli cochlear implantation in patients with partially ossified cochleas.

    Science.gov (United States)

    Berrettini, Stefano; Forli, Francesca; Neri, Emanuele; Segnini, Giovanni; Franceschini, Stefano Sellari

    2002-11-01

    Partial cochlear obstruction is a relatively common finding in candidates for cochlear implants and frequently involves the inferior segment of the scala tympani in the basal turn of the cochlea. In such patients, the scala vestibuli is often patent and offers an alternative site for implantation. The current report describes two patients with such partial obstruction of the inferior segment of the basal cochlear turn, caused in one case by systemic vasculitis (Takayasu's disease) and in the other by obliterative otosclerosis. A scala vestibuli implantation allowed for complete insertion of the electrode array. No problems were encountered during the surgical procedures and the good post-operative hearing and communicative outcomes achieved were similar to those reported in patients without cochlear ossification. The importance of accurate pre-operative radiological study of the inner ear is underscored, to disclose the presence and define the features of the cochlear ossification and ultimately to properly plan the surgical approach.

  5. Spiral Form of the Human Cochlea Results from Spatial Constraints.

    Science.gov (United States)

    Pietsch, M; Aguirre Dávila, L; Erfurt, P; Avci, E; Lenarz, T; Kral, A

    2017-08-08

    The human inner ear has an intricate spiral shape often compared to shells of mollusks, particularly to the nautilus shell. It has inspired many functional hearing theories. The reasons for this complex geometry remain unresolved. We digitized 138 human cochleae at microscopic resolution and observed an astonishing interindividual variability in the shape. A 3D analytical cochlear model was developed that fits the analyzed data with high precision. The cochlear geometry neither matched a proposed function, namely sound focusing similar to a whispering gallery, nor did it have the form of a nautilus. Instead, the innate cochlear blueprint and its actual ontogenetic variants were determined by spatial constraints and resulted from an efficient packing of the cochlear duct within the petrous bone. The analytical model predicts well the individual 3D cochlear geometry from few clinical measures and represents a clinical tool for an individualized approach to neurosensory restoration with cochlear implants.

  6. Effects of 60Co γ-ray radiation on cochlea in guinea pigs

    International Nuclear Information System (INIS)

    Fan Jingping; Lu Shuchang; Hu Zhengyan; Shi Xiufeng

    1992-01-01

    The effects of different doses of γ-ray on cochlea are reported. Significant hearing loss and severe cochlea hair cells injury were found while radiation dose was more than 80 Gy. With 40 Gy to 60 Gy, slight hearing loss, but cochlea hair cells and support cells impairment were observed. With 20 Gy, no hearing loss and no hair cell damage were found. The results indicated that the damage increases with a dose of radiation and there is a delay effect of radiation on cochles

  7. Thromboelastography in Selected Avian Species

    DEFF Research Database (Denmark)

    Andersen, Sophie Susanna Strindberg; Nielsen, Tenna W; Ribeiro, Ângela M

    2015-01-01

    Currently available assay methods and reagents are not optimized for evaluating avian hemostasis; therefore, assessing avian coagulopathies is challenging. Recently, thromboelastography (TEG), which measures the viscoelastic properties of blood, has been used clinically in mammalian species...... to diagnose and characterize hemostatic disorders. To evaluate TEG in healthy individuals of 6 avian species, we modified existing mammalian TEG protocols to allow analysis of citrated, avian whole-blood samples collected from scarlet ibis (Eudocimus ruber) (n = 13), American flamingos ( Phoenicopterus ruber...

  8. Modeling Analysis of Biomechanical Changes of Middle Ear and Cochlea in Otitis Media

    Science.gov (United States)

    Gan, Rong Z.; Zhang, Xiangming; Guan, Xiying

    2011-11-01

    A comprehensive finite element (FE) model of the human ear including the ear canal, middle ear, and spiral cochlea was developed using histological sections of human temporal bone. The cochlea was modeled with three chambers separated by the basilar membrane and Reissner's membrane and filled with perilymphatic fluid. The viscoelastic material behavior was applied to middle ear soft tissues based on dynamic measurements of tissues in our lab. The model was validated using the experimental data obtained in human temporal bones and then used to simulate various stages of otitis media (OM) including the changes of morphology, mechanical properties, pressure, and fluid level in the middle ear. Function alterations of the middle ear and cochlea in OM were derived from the model and compared with the measurements from temporal bones. This study indicates that OM can be simulated in the FE model to predict the hearing loss induced by biomechanical changes of the middle ear and cochlea.

  9. The difference in endolymphatic hydrostatic pressure elevation induced by isoproterenol between the ampulla and the cochlea.

    Science.gov (United States)

    Inamoto, Ryuhei; Miyashita, Takenori; Matsubara, Ai; Hoshikawa, Hiroshi; Mori, Nozomu

    2017-06-01

    The purpose of the study was to investigate the difference in the responses of endolymphatic hydrostatic pressure to isoproterenol, β-adrenergic receptor agonist, between pars superior and pars inferior. The hydrostatic pressure of endolymph and perilymph and endolymphatic potential in the ampulla and the cochlea during the intravenous administration of isoproterenol were recorded using a servo-null system in guinea pigs. The hydrostatic pressure of endolymph and perilymph in the ampulla and cochlea was similar in magnitude. Isoproterenol significantly increased hydrostatic pressure of ampullar and cochlear endolymph and perilymph with no change in the ampullar endolymphatic potential and endocochlear potential, respectively. The isoproterenol-induced maximum change of endolymphatic hydrostatic pressure in ampulla was significantly (phydrostatic pressure in the ampulla disappeared like that in the cochlea. Isoproterenol elevates endolymphatic hydrostatic pressure in different manner between the vestibule and the cochlea. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. THE POTENTIAL ROLE OF ENDOGENOUS STEM CELLS IN REGENERATION OF THE INNER EAR

    Science.gov (United States)

    Martinez-Monedero, Rodrigo; Oshima, Kazuo; Heller, Stefan; Edge, Albert S.B.

    2007-01-01

    Stem cells in various mammalian tissues retain the capacity to renew themselves and may be able to restore damaged tissue. Their existence has been proven by genetic tracer studies that demonstrate their differentiation into multiple tissue types and by their ability to self-renew through proliferation. Stem cells from the adult nervous system proliferate to form clonal floating colonies called spheres in vitro, and recent studies have demonstrated sphere formation by cells in the cochlea in addition to the vestibular system and the auditory ganglia, indicating that these tissues contain cells with stem cell properties. The presence of stem cells in the inner ear raises the hope of regeneration of mammalian inner ear cells but is difficult to correlate with the lack spontaneous regeneration seen in the inner ear after tissue damage. Loss of stem cells postnatally in the cochlea may correlate with the loss of regenerative capacity and may limit our ability to stimulate regeneration. Retention of sphere forming capacity in adult vestibular tissues suggests that the limited capacity for repair may be attributed to the continued presence of progenitor cells. Future strategies for regeneration must consider the distribution of endogenous stem cells in the inner ear and whether cells with the capacity for regeneration are retained. PMID:17321086

  11. Cardiomyocyte Regeneration

    Directory of Open Access Journals (Sweden)

    Toshio Nakanishi

    2013-01-01

    Full Text Available The heart was initially believed to be a terminally differentiated organ; once the cardiomyocytes died, no recovery could be made to replace the dead cells. However, around a decade ago, the concept of cardiac stem cells (CSCs in adult hearts was proposed. CSCs differentiate into cardiomyocytes, keeping the heart functioning. Studies have proved the existence of stem cells in the heart. These somatic stem cells have been studied for use in cardiac regeneration. Moreover, recently, induced pluripotent stem cells (iPSCs were invented, and methodologies have now been developed to induce stable cardiomyocyte differentiation and purification of mature cardiomyocytes. A reprogramming method has also been applied to direct reprogramming using cardiac fibroblasts into cardiomyocytes. Here, we address cardiomyocyte differentiation of CSCs and iPSCs. Furthermore, we describe the potential of CSCs in regenerative biology and regenerative medicine.

  12. Heart regeneration.

    Science.gov (United States)

    Breckwoldt, Kaja; Weinberger, Florian; Eschenhagen, Thomas

    2016-07-01

    Regenerating an injured heart holds great promise for millions of patients suffering from heart diseases. Since the human heart has very limited regenerative capacity, this is a challenging task. Numerous strategies aiming to improve heart function have been developed. In this review we focus on approaches intending to replace damaged heart muscle by new cardiomyocytes. Different strategies for the production of cardiomyocytes from human embryonic stem cells or human induced pluripotent stem cells, by direct reprogramming and induction of cardiomyocyte proliferation are discussed regarding their therapeutic potential and respective advantages and disadvantages. Furthermore, different methods for the transplantation of pluripotent stem cell-derived cardiomyocytes are described and their clinical perspectives are discussed. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Highly pathogenic avian influenza.

    Science.gov (United States)

    Swayne, D E; Suarez, D L

    2000-08-01

    Highly pathogenic (HP) avian influenza (AI) (HPAI) is an extremely contagious, multi-organ systemic disease of poultry leading to high mortality, and caused by some H5 and H7 subtypes of type A influenza virus, family Orthomyxoviridae. However, most AI virus strains are mildly pathogenic (MP) and produce either subclinical infections or respiratory and/or reproductive diseases in a variety of domestic and wild bird species. Highly pathogenic avian influenza is a List A disease of the Office International des Epizooties, while MPAI is neither a List A nor List B disease. Eighteen outbreaks of HPAI have been documented since the identification of AI virus as the cause of fowl plague in 1955. Mildly pathogenic avian influenza viruses are maintained in wild aquatic bird reservoirs, occasionally crossing over to domestic poultry and causing outbreaks of mild disease. Highly pathogenic avian influenza viruses do not have a recognised wild bird reservoir, but can occasionally be isolated from wild birds during outbreaks in domestic poultry. Highly pathogenic avian influenza viruses have been documented to arise from MPAI viruses through mutations in the haemagglutinin surface protein. Prevention of exposure to the virus and eradication are the accepted methods for dealing with HPAI. Control programmes, which imply allowing a low incidence of infection, are not an acceptable method for managing HPAI, but have been used during some outbreaks of MPAI. The components of a strategy to deal with MPAI or HPAI include surveillance and diagnosis, biosecurity, education, quarantine and depopulation. Vaccination has been used in some control and eradication programmes for AI.

  14. Avian influenza: a review.

    Science.gov (United States)

    Thomas, Jennifer K; Noppenberger, Jennifer

    2007-01-15

    A review of the avian influenza A/H5N1 virus, including human cases, viral transmission, clinical features, vaccines and antivirals, surveillance plans, infection control, and emergency response plans, is presented. The World Health Organization (WHO) considers the avian influenza A/H5N1 virus a public health risk with pandemic potential. The next human influenza pandemic, if caused by the avian influenza A/H5N1 virus, is estimated to have a potential mortality rate of more than a hundred million. Outbreaks in poultry have been associated with human transmission. WHO has documented 258 confirmed human infections with a mortality rate greater than 50%. Bird-to-human transmission of the avian influenza virus is likely by the oral-fecal route. The most effective defense against an influenza pandemic would be a directed vaccine to elicit a specific immune response toward the strain or strains of the influenza virus. However, until there is an influenza pandemic, there is no evidence that vaccines or antivirals used in the treatment or prevention of such an outbreak would decrease morbidity or mortality. Surveillance of the bird and human populations for the highly pathogenic H5N1 is being conducted. Infection-control measures and an emergency response plan are discussed. Avian influenza virus A/H5N1 is a public health threat that has the potential to cause serious illness and death in humans. Understanding its pathology, transmission, clinical features, and pharmacologic treatments and preparing for the prevention and management of its outbreak will help avoid its potentially devastating consequences.

  15. Piribedil affects dopamine turnover in cochleas stimulated by white noise.

    Science.gov (United States)

    Gil-Loyzaga, P; Vicente-Torres, M A; Fernández-Mateos, P; Arce, A; Esquifino, A

    1994-09-01

    The presence of dopamine (DA) within the cochlea has been previously reported, indicating that its turnover increases under noise stimulation. In the present report, piribedil, a dopaminergic D2 agonist, was used in order to provide evidence of the activity of D2 receptors in the turnover of DA under noise stimulation. Long-Evans rats were intraperitoneally injected with distilled water or with a solution of piribedil one hour previously to either noise or silence exposure. Noise stimulation was performed in an anechoic chamber at 70, 90 or 110 dB SPL for one hour. The animals were then sacrificed and the cochlear contents of DA and its metabolites dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were quantified by HPLC with electrochemical detection. The administration of piribedil to animals kept in silence did not modify the cochlear DA, DOPAC and HVA content. Noise stimulation resulted in a decrease of the cochlear DA content and an increase of the cochlear DOPAC and HVA contents in vehicle treated animals. The administration of piribedil resulted in a blockade of this noise induced cochlear DA turnover. These results suggest that piribedil stimulates cochlear D2 receptors controlling the cochlear DA release. Piribedil action on D2 receptors could explain the improvement observed in some cochleo-vestibular diseases signs after piribedil treatment.

  16. Cognitive task demands modulate the sensitivity of the human cochlea

    Directory of Open Access Journals (Sweden)

    David W Smith

    2012-02-01

    Full Text Available Recent studies lead to the conclusion that focused attention, through the activity of corticofugal and medial olivocochlear efferent pathways, modulates activity at the most peripheral aspects of the auditory system within the cochlea. In two experiments we investigated the effects of different intermodal attention manipulations on the response of outer hair cells (OHCs, and the control exerted by the medial olivocochlear (MOC efferent system. The effect of the MOCs on OHC activity was characterized by measuring the amplitude and rapid adaptation time course of distortion product otoacoustic emissions (DPOAEs. In the first, DPOAE recordings were compared while participants were reading a book and counting the occurrence of the letter a (auditory ignoring and while counting the either short- or long-duration eliciting tones (auditory attending. In the second, DPOAEs were recorded while subjects watched muted movies with subtitles (auditory ignoring/visual distraction and were compared with DPOAEs recorded while subjects counted the same tones (auditory attending as in experiment 1. In both experiments 1 and 2, the absolute level of the averaged DPOAEs recorded during the auditory-ignoring condition was statistically higher than that recorded in the auditory-attending condition. Efferent-induced rapid adaptation was evident in all DPOAE contours, under all attention conditions, suggesting that two medial efferent processes act independently to determine rapid adaptation, which is unaffected by attention, and the overall DPOAE level, which is significantly affected by changes in the focus of attention.

  17. Curcumin protects against acoustic trauma in the rat cochlea.

    Science.gov (United States)

    Soyalıç, Harun; Gevrek, Fikret; Karaman, Serhat

    2017-08-01

    In this study we evaluated the therapeutic utility of curcumin in a rodent model of acoustic trauma using histopathology, immunohistochemical, and distortion product otoacoustic emission (DPOAEs) measurements. 28 Wistar albino rats were included in the study and randomly assigned to 4 treatment groups. The first group (group 1) served as the control and was exposed to acoustic trauma alone. Group 2 was the curcumin group. Group 3 was the curcumin plus acoustic trauma group. Group 4 was the saline plus acoustic trauma group. Otoacoustic emission measurements were collected at the end of the experiment and all animals were sacrificed. Cochlea were collected and prepared for TUNEL (TdT-mediated deoxyuridinetriphosphate nick end-labelling) staining assay. Group 3 maintained baseline DPOAEs values at 3000 Hz, 4000 Hz and 8000 Hz on the 3rd and 5th day of the experiment. DPOAEs results were correlated with the immunohistochemical and histopathological findings in all groups. In comparison to the histopathologic control group, Group 1 exhibited a statistically significant increase in apoptotic indices in the organ of Corti, inner hair cell, and outer hair cell areas (p curcumin may protect the cochlear tissues from acoustic trauma in rats. Curcumin injection prior to or after an acoustic trauma reduces cochlear hair cell damage and may protect against hearing loss. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Avian Influenza A Virus Infections in Humans

    Science.gov (United States)

    ... people has ranged from mild to severe. Avian Influenza Transmission Avian Influenza Transmission Infographic [555 KB, 2 pages] Spanish [ ... important for public health. Signs and Symptoms of Avian Influenza A Virus Infections in Humans The reported signs ...

  19. Implanting straight into cochlea risks the facial nerve: a Cartesian coordinate study.

    Science.gov (United States)

    Deshpande, Anita S; Wendell Todd, N

    2016-12-01

    To describe the straight-into-cochlea line that affords the best access for an electrode array to enter via the round window, and how this line relates to the facial nerve, the incus, and mastoid size. The straight-into-cochlea line is important to minimize the cochlear trauma and maximize the likelihood of placement into the scala tympani. High-resolution CT scans were obtained for ten craniums with the extremes of large (N = 5) and small (N = 5) mastoid pneumatization; the specimens were from a series of 41 ear normal craniums. Using FIJI, a publicly available software program, the straight-into-cochlea insertion line was determined by defining the x-y-z coordinates of the middle of the round window and a point 6.0 mm into the cochlea on its centrifugal wall. Then, from the extended straight-into-cochlea insertion line, we determined the shortest perpendicular distance to the middle of the fallopian canal, and from that "fallopian point" to the apex of the posterior process of the incus. We found good repeatability of measurements. We found the extended straight-into-cochlea insertion lines routinely close to or in the midst of the fallopian canal (50 % ≤ 1.0 mm). We found the lines 4.7-7.8 mm from the apex of the posterior process of the incus. Line positions relative to "fallopian point" and incus showed no relation to mastoid pneumatization. For the distance "fallopian point" to incus, bilateral symmetry was suggested. Using landmarks registered in an x-y-z coordinate system, straight-into-cochlea insertion via the round window puts the facial nerve at risk.

  20. Inactivation of STAT3 Signaling Impairs Hair Cell Differentiation in the Developing Mouse Cochlea.

    Science.gov (United States)

    Chen, Qianqian; Quan, Yizhou; Wang, Naitao; Xie, Chengying; Ji, Zhongzhong; He, Hao; Chai, Renjie; Li, Huawei; Yin, Shankai; Chin, Y Eugene; Wei, Xunbin; Gao, Wei-Qiang

    2017-07-11

    Although STAT3 signaling is demonstrated to regulate sensory cell differentiation and regeneration in the zebrafish, its exact role is still unclear in mammalian cochleae. Here, we report that STAT3 and its activated form are specifically expressed in hair cells during mouse cochlear development. Importantly, conditional cochlear deletion of Stat3 leads to an inhibition on hair cell differentiation in mice in vivo and in vitro. By cell fate analysis, inactivation of STAT3 signaling shifts the cell division modes from asymmetric to symmetric divisions from supporting cells. Moreover, inhibition of Notch signaling stimulates STAT3 phosphorylation, and inactivation of STAT3 signaling attenuates production of supernumerary hair cells induced by a Notch pathway inhibitor. Our findings highlight an important role of the STAT3 signaling during mouse cochlear hair cell differentiation and may have clinical implications for the recovery of hair cell loss-induced hearing impairment. Copyright © 2017 International Society for Stem Cell Research. Published by Elsevier Inc. All rights reserved.

  1. Grid attacks avian flu

    CERN Multimedia

    2006-01-01

    During April, a collaboration of Asian and European laboratories analysed 300,000 possible drug components against the avian flu virus H5N1 using the EGEE Grid infrastructure. Schematic presentation of the avian flu virus.The distribution of the EGEE sites in the world on which the avian flu scan was performed. The goal was to find potential compounds that can inhibit the activities of an enzyme on the surface of the influenza virus, the so-called neuraminidase, subtype N1. Using the Grid to identify the most promising leads for biological tests could speed up the development process for drugs against the influenza virus. Co-ordinated by CERN and funded by the European Commission, the EGEE project (Enabling Grids for E-sciencE) aims to set up a worldwide grid infrastructure for science. The challenge of the in silico drug discovery application is to identify those molecules which can dock on the active sites of the virus in order to inhibit its action. To study the impact of small scale mutations on drug r...

  2. Influence of Young's moduli in 3D fluid-structure coupled models of the human cochlea

    Science.gov (United States)

    Böhnke, Frank; Semmelbauer, Sebastian; Marquardt, Torsten

    2015-12-01

    The acoustic wave propagation in the human cochlea was studied using a tapered box-model with linear assumptions respective to all mechanical parameters. The discretisation and evaluation is conducted by a commercial finite element package (ANSYS). The main difference to former models of the cochlea was the representation of the basilar membrane by a 3D elastic solid. The Young's moduli of this solid were modified to study their influence on the travelling wave. The lymph in the scala vestibuli and scala tympani was represented by a viscous and nearly incompressible fluid finite element approach. Our results show the maximum displacement for f = 2kHz at half of the length of the cochlea in accordance with former experiments. For low frequencies f <200 Hz nearly zero phase shifts were found, whereas for f =1 kHz it reaches values up to -12 cycles depending on the degree of orthotropy.

  3. Simple landmark for preservation of the cochlea during maximum drilling of the petrous apex through the anterior transpetrosal approach

    International Nuclear Information System (INIS)

    Seo, Yoshinobu; Sasaki, Takehiko; Nakamura, Hirohiko

    2010-01-01

    The cochlea is one of the most important organs to preserve during skull base surgery. However, no definite landmark for the cochlea has been identified during maximum drilling of the petrous apex such as anterior transpetrosal approach. The relationship between the cochlea and the petrous portion of the internal carotid artery (ICA) was assessed with computed tomography (CT) in 70 petrous bones of 35 patients, 16 males and 19 females aged 12-85 years (mean 48.6 years). After accumulation of volume data with multidetector CT, axial bone window images of 1-mm thickness were obtained to identify the cochlea and the horizontal petrous portion of the ICA. The distance was measured between the extended line of the posteromedial side of the horizontal petrous portion of the ICA and the basal turn of the cochlea. If the cochlea was located posteromedial to the ICA, the distance was expressed as a positive number, but if anterolateral, as a negative number. The mean distance was 0.6 mm (range -4.9 to 3.9 mm) and had no significant correlation with sex or age. The cochlea varies in location compared with the horizontal petrous portion of the ICA. Measurement of the depth and distance between the extended line of the posteromedial side of the horizontal intrapetrous ICA and the cochlea before surgery will save time, increase safety, and maximize bone evacuation during drilling of the petrous apex. (author)

  4. LGR4 and LGR5 regulate hair cell differentiation in the sensory epithelium of the developing mouse cochlea

    NARCIS (Netherlands)

    Zak, Magdalena; Van Oort, Thijs; Hendriksen, Ferry G.; Garcia, Marie Isabelle; Vassart, Gilbert; Grolman, Wilko

    2016-01-01

    In the developing cochlea, Wnt/β-catenin signaling positively regulates the proliferation of precursors and promotes the formation of hair cells by up-regulating Atoh1 expression. Not much, however, is known about the regulation of Wnt/β-catenin activity in the cochlea. In multiple tissues, the

  5. Gap junction mediated intercellular metabolite transfer in the cochlea is compromised in connexin30 null mice.

    Directory of Open Access Journals (Sweden)

    Qing Chang

    Full Text Available Connexin26 (Cx26 and connexin30 (Cx30 are two major protein subunits that co-assemble to form gap junctions (GJs in the cochlea. Mutations in either one of them are the major cause of non-syndromic prelingual deafness in humans. Because the mechanisms of cochlear pathogenesis caused by Cx mutations are unclear, we investigated effects of Cx30 null mutation on GJ-mediated ionic and metabolic coupling in the cochlea of mice. A novel flattened cochlear preparation was used to directly assess intercellular coupling in the sensory epithelium of the cochlea. Double-electrode patch clamp recordings revealed that the absence of Cx30 did not significantly change GJ conductance among the cochlear supporting cells. The preserved electrical coupling is consistent with immunolabeling data showing extensive Cx26 GJs in the cochlea of the mutant mice. In contrast, dye diffusion assays showed that the rate and extent of intercellular transfer of multiple fluorescent dyes (including a non-metabolizable D-glucose analogue, 2-NBDG among cochlear supporting cells were severely reduced in Cx30 null mice. Since the sensory epithelium in the cochlea is an avascular organ, GJ-facilitated intercellular transfer of nutrient and signaling molecules may play essential roles in cellular homeostasis. To test this possibility, NBDG was used as a tracer to study the contribution of GJs in transporting glucose into the cochlear sensory epithelium when delivered systemically. NBDG uptake in cochlear supporting cells was significantly reduced in Cx30 null mice. The decrease was also observed with GJ blockers or glucose competition, supporting the specificity of our tests. These data indicate that GJs facilitate efficient uptake of glucose in the supporting cells. This study provides the first direct experimental evidence showing that the transfer of metabolically-important molecules in cochlear supporting cells is dependent on the normal function of GJs, thereby suggesting a

  6. Avian influenza surveillance and diagnosis

    Science.gov (United States)

    Rapid detection and accurate identification of low (LPAI) and high pathogenicity avian influenza (HPAI) is critical to controlling infections and disease in poultry. Test selection and algorithms for the detection and diagnosis of avian influenza virus (AIV) in poultry may vary somewhat among differ...

  7. Characterizing and modeling dynamic processes in the cochlea using otoacoustic emissions

    DEFF Research Database (Denmark)

    Verhulst, Sarah

    2010-01-01

    mechanism is essential for our hearing and degrades when hearing impairment develops. A comprehensive understanding of the gain involved in the intact human cochlea is crucial, as hearing instruments try to compensate for the loss in cochlear gain caused by hearing damage. This thesis investigates dynamic......An important characteristic of human hearing is that it amplifies weak sounds while attenuating louder ones. This gain transformation takes place in the inner ear (i.e., cochlea), and is responsible for a compressive relation between the level of the presented and perceived sound. The cochlear gain...... constant in cochlear compression may be of interest for the future development of signal processing in hearing instruments....

  8. The traveling-wave amplifier model of the cochlea adapted to dolphins

    DEFF Research Database (Denmark)

    Andersen, Lars Nonboe; Au, W.W.L.

    1999-01-01

    The traveling-wave amplifier (TWA) model of the cochlea [A. Hubbard, Science 259, 68–71 (1993)] has been shown to produce outputs that compare quite well with experimental data. A TWA model with parameters adjusted to fit the physiological properties of the dolphin cochlea was used as part...... of a sonar signal discrimination system. The system was tested on a cylinder wall thickness discrimination problem. Broadband echoes from cylinders with different wall thicknesses were aligned using a matched filter and envelope detection. The aligned signals were used as inputs to the TWA model and energy...

  9. 76 FR 24793 - Highly Pathogenic Avian Influenza

    Science.gov (United States)

    2011-05-03

    .... APHIS-2006-0074] RIN 0579-AC36 Highly Pathogenic Avian Influenza AGENCY: Animal and Plant Health... any subtype of highly pathogenic avian influenza is considered to exist. The interim rule also imposed... avian influenza, or that have moved through regions where any subtype of highly pathogenic avian...

  10. Clinical avian nutrition.

    Science.gov (United States)

    Orosz, Susan E

    2014-09-01

    Psittacine birds eat plant-based foods. Birds in the wild seem to be able to balance their energy needs, amino acids, and calcium. Companion birds in captivity do not do as well when self-selecting, and balanced diets are needed to improve their general health. A nutritional history is important to determine whether the avian patient is in balance nutritionally. Understanding the various sources of the fat-soluble vitamins, calcium, and protein will help guide clients to provide nutritious foods for their birds. Owners need to learn to use foraging as a major source of their bird's diet and techniques. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Avian and human metapneumovirus.

    Science.gov (United States)

    Broor, Shobha; Bharaj, Preeti

    2007-04-01

    Pneumovirus infection remains a significant problem for both human and veterinary medicine. Both avian pneumovirus (aMPV, Turkey rhinotracheitis virus) and human metapneumovirus (hMPV) are pathogens of birds and humans, which are associated with respiratory tract infections. Based on their different genomic organization and low level of nucleotide (nt) and amino acid (aa) identity with paramyxoviruses in the genus Pneumovirus, aMPV and hMPV have been classified into a new genus referred to as Metapneumovirus. The advancement of our understanding of pneumovirus biology and pathogenesis of pneumovirus disease in specific natural hosts can provide us with strategies for vaccine formulations and combined antiviral and immunomodulatory therapies.

  12. Dead regions in the cochlea: Implications for speech recognition and applicability of articulation index theory

    DEFF Research Database (Denmark)

    Vestergaard, Martin David

    2003-01-01

    Dead regions in the cochlea have been suggested to be responsible for failure by hearing aid users to benefit front apparently increased audibility in terms of speech intelligibility. As an alternative to the more cumbersome psychoacoustic tuning curve measurement, threshold-equalizing noise (TEN...

  13. Minimally invasive drug delivery to the cochlea through application of nanoparticles to the round window membrane

    Czech Academy of Sciences Publication Activity Database

    Buckiová, Daniela; Ranjan, S.; Newman, T. A.; Johnston, A. H.; Sood, R.; Kinnunen, P. K. J.; Popelář, Jiří; Chumak, Tetyana; Syka, Josef

    2012-01-01

    Roč. 7, č. 9 (2012), s. 1339-1354 ISSN 1743-5889 R&D Projects: GA ČR GA309/07/1336; GA MŠk(CZ) LC554 Institutional research plan: CEZ:AV0Z50390512 Keywords : nanoparticles * cochlea * drug delivery Subject RIV: FH - Neurology Impact factor: 5.260, year: 2012

  14. Reconstruction of Cochlea Based on Micro-CT and Histological Images of the Human Inner Ear

    Directory of Open Access Journals (Sweden)

    Christos Bellos

    2014-01-01

    Full Text Available The study of the normal function and pathology of the inner ear has unique difficulties as it is inaccessible during life and, so, conventional techniques of pathologic studies such as biopsy and surgical excision are not feasible, without further impairing function. Mathematical modelling is therefore particularly attractive as a tool in researching the cochlea and its pathology. The first step towards efficient mathematical modelling is the reconstruction of an accurate three dimensional (3D model of the cochlea that will be presented in this paper. The high quality of the histological images is being exploited in order to extract several sections of the cochlea that are not visible on the micro-CT (mCT images (i.e., scala media, spiral ligament, and organ of Corti as well as other important sections (i.e., basilar membrane, Reissner membrane, scala vestibule, and scala tympani. The reconstructed model is being projected in the centerline of the coiled cochlea, extracted from mCT images, and represented in the 3D space. The reconstruction activities are part of the SIFEM project, which will result in the delivery of an infrastructure, semantically interlinking various tools and libraries (i.e., segmentation, reconstruction, and visualization tools with the clinical knowledge, which is represented by existing data, towards the delivery of a robust multiscale model of the inner ear.

  15. Anatomic variations of the cochlea and relations to other temporal bone structures

    Energy Technology Data Exchange (ETDEWEB)

    Dimopoulos, P.; Muren, C. (Akademiska Sjukhuset, Uppsala (Sweden). Dept. of Diagnostic Radiology Sabbatsberg' s Sjukhus, Stockholm (Sweden). Dept. of Diagnostic Radiology)

    1990-09-01

    The size and shape of the human cochlea and the normal ranges of variation of its dimensions were evaluated in 95 plastic casts, prepared from temporal bone specimens. The normal range of variation is fairly small, and is not age-dependent. Obvious digression from this range, associated with pertinent clinical symptoms, indicates an abnormality. (orig./MG).

  16. Optical path of infrared neural stimulation in the guinea pig and cat cochlea

    Science.gov (United States)

    Rajguru, Suhrud M.; Hwang, Margaret; Moreno, Laura E.; Matic, Agnella I.; Stock, Stuart R.; Richter, Claus-Peter

    2011-03-01

    It has been demonstrated previously that infrared neural stimulation (INS) can be used to stimulate spiral ganglion cells in the cochlea. With INS, neural stimulation can be achieved without direct contact of the radiation source and the tissue and is spatially well resolved. The presence of fluids or bone between the target structure and the radiation source may lead to absorption or scattering of the radiation and limit the efficacy of INS. To develop INS based cochlear implants, it is critical to determine the beam path of the radiation in the cochlea. In the present study, we utilized noninvasive X-ray microtomography (microCT) to visualize the orientation and location of the optical fiber within the guinea pig and cat cochlea. Overall, the results indicated that the optical fiber was directed towards the spiral ganglion cells in the cochlea and not the nerve fibers in the center of the modiolus. The fiber was approximately 300 μm away from the target structures. In future studies, results from the microCT will be correlated with physiology obtained from recordings in the midbrain.

  17. Cellular development of the human cochlea and the regenerative potential of hair follicle bulge stem cells

    NARCIS (Netherlands)

    Locher, heiko

    2015-01-01

    The embryonic development of the human cochlea (the organ of hearing) has been investigated for over one hundred years. However, little is still known about the development on a cellular and protein level, which is important to better understand etiologies and pathologies of various types of

  18. Defining the cellular environment in the organ of Corti following extensive hair cell loss: a basis for future sensory cell replacement in the Cochlea.

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    Ruth R Taylor

    Full Text Available BACKGROUND: Following the loss of hair cells from the mammalian cochlea, the sensory epithelium repairs to close the lesions but no new hair cells arise and hearing impairment ensues. For any cell replacement strategy to be successful, the cellular environment of the injured tissue has to be able to nurture new hair cells. This study defines characteristics of the auditory sensory epithelium after hair cell loss. METHODOLOGY/PRINCIPAL FINDINGS: Studies were conducted in C57BL/6 and CBA/Ca mice. Treatment with an aminoglycoside-diuretic combination produced loss of all outer hair cells within 48 hours in both strains. The subsequent progressive tissue re-organisation was examined using immunohistochemistry and electron microscopy. There was no evidence of significant de-differentiation of the specialised columnar supporting cells. Kir4.1 was down regulated but KCC4, GLAST, microtubule bundles, connexin expression patterns and pathways of intercellular communication were retained. The columnar supporting cells became covered with non-specialised cells migrating from the outermost region of the organ of Corti. Eventually non-specialised, flat cells replaced the columnar epithelium. Flat epithelium developed in distributed patches interrupting regions of columnar epithelium formed of differentiated supporting cells. Formation of the flat epithelium was initiated within a few weeks post-treatment in C57BL/6 mice but not for several months in CBA/Ca's, suggesting genetic background influences the rate of re-organisation. CONCLUSIONS/SIGNIFICANCE: The lack of dedifferentiation amongst supporting cells and their replacement by cells from the outer side of the organ of Corti are factors that may need to be considered in any attempt to promote endogenous hair cell regeneration. The variability of the cellular environment along an individual cochlea arising from patch-like generation of flat epithelium, and the possible variability between individuals

  19. Grafting and early expression of growth factors from adipose-derived stem cells transplanted into the cochlea, in a guinea pig model of acoustic trauma

    Directory of Open Access Journals (Sweden)

    Anna Rita Fetoni

    2014-10-01

    Full Text Available Noise exposure causes damage of multiple cochlear cell types producing permanent hearing loss with important social consequences. In mammals, no regeneration of either damaged hair cells or auditory neurons has been observed and no successful treatment is available to achieve a functional recovery. Several evidences indicate adipose-derived stem cells (ASCs as promising tools in diversified regenerative medicine applications, due to the high degree of plasticity and trophic features.This study was aimed at identifying the path of in vivo cell migration and expression of trophic growth factors, upon ASC transplantation into the cochlea, following noise-induced injury. ASCs were isolated in primary culture from the adipose tissue of a guinea pig, transduced using a viral vector to express the green fluorescent protein, and implanted into the scala tympani of deafened animals. Auditory function was assessed 3 and 7 days after surgery. The expression of trophic growth factors was comparatively analyzed using real time PCR in control and noise-injured cochlear tissues. Immunofluorescence was used to assess the in vivo localization and expression of trophic growth factors in ASCs and cochleae, 3 and 7 days following homologous implantation. ASC implantation did not modify auditory function. ASCs migrated from the perilymphatic to the endolymphatic compartment, during the analyzed time course. Upon noise exposure, the expression of chemokine ligands and receptors related to the PDGF, VEGF and TGFbeta pathways, increased in the cochlear tissues, possibly guiding in vivo cell migration. Immunofluorescence confirmed the increased expression, which appeared to be further strengthened by ASC implantation.These results indicate that ASCs are able to migrate at the site of tissue damage and express trophic factors, upon intracochlear implantantion, providing an original proof of principle, which could pave the way for further developments of ASC

  20. Characterization of Lgr6+ Cells as an Enriched Population of Hair Cell Progenitors Compared to Lgr5+ Cells for Hair Cell Generation in the Neonatal Mouse Cochlea

    Directory of Open Access Journals (Sweden)

    Yanping Zhang

    2018-05-01

    Full Text Available Hair cell (HC loss is irreversible because only very limited HC regeneration has been observed in the adult mammalian cochlea. Wnt/β-catenin signaling regulates prosensory cell proliferation and differentiation during cochlear development, and Wnt activation promotes the proliferation of Lgr5+ cochlear HC progenitors in newborn mice. Similar to Lgr5, Lgr6 is also a Wnt downstream target gene. Lgr6 is reported to be present in adult stem cells in the skin, nail, tongue, lung, and mammary gland, and this protein is very important for adult stem cell maintenance in rapidly proliferating organs. Our previous studies showed that Lgr6+ cells are a subpopulation of Lgr5+ progenitor cells and that both Lgr6+ and Lgr5+ progenitors can generate Myosin7a+ HCs in vitro. Thus we hypothesized that Lgr6+ cells are an enriched population of cochlear progenitor cells. However, the detailed distinctions between the Lgr5+ and Lgr6+ progenitors are unclear. Here, we systematically compared the proliferation, HC differentiation, and detailed transcriptome expression profiles of these two progenitor populations. We found that the same number of isolated Lgr6+ progenitors generated significantly more Myosin7a+ HCs compared to Lgr5+ progenitors; however, Lgr5+ progenitors formed more epithelial colonies and more spheres than Lgr6+ progenitors in vitro. Using RNA-Seq, we compared the transcriptome differences between Lgr5+ and Lgr6+ progenitors and identified a list of significantly differential expressed genes that might regulate the proliferation and differentiation of these HC progenitors, including 4 cell cycle genes, 9 cell signaling pathway genes, and 54 transcription factors. In conclusion, we demonstrate that Lgr6+ progenitors are an enriched population of inner ear progenitors that generate more HCs compared to Lgr5+ progenitors in the newborn mouse cochlea, and the our research provides a series of genes that might regulate the proliferation of progenitors

  1. Influenza pandemics and avian flu

    OpenAIRE

    Fleming, Douglas

    2005-01-01

    Douglas Fleming is general practitioner in a large suburban practice in Birmingham. In this article he seeks to clarify clinical issues relating to potential pandemics of influenza, including avian influenza

  2. Diphtheria Toxin-Induced Cell Death Triggers Wnt-Dependent Hair Cell Regeneration in Neonatal Mice.

    Science.gov (United States)

    Hu, Lingxiang; Lu, Jingrong; Chiang, Hao; Wu, Hao; Edge, Albert S B; Shi, Fuxin

    2016-09-07

    Cochlear hair cells (HCs), the sensory cells that respond to sound, do not regenerate after damage in adult mammals, and their loss is a major cause of deafness. Here we show that HC regeneration in newborn mouse ears occurred spontaneously when the original cells were ablated by treatment with diphtheria toxin (DT) in ears that had been engineered to overexpress the DT receptor, but was not detectable when HCs were ablated in vivo by the aminoglycoside antibiotic neomycin. A variety of Wnts (Wnt1, Wnt2, Wnt2b, Wnt4, Wnt5a, Wnt7b, Wnt9a, Wnt9b, and Wnt11) and Wnt pathway component Krm2 were upregulated after DT damage. Nuclear β-catenin was upregulated in HCs and supporting cells of the DT-damaged cochlea. Pharmacological inhibition of Wnt decreased spontaneous regeneration, confirming a role of Wnt signaling in HC regeneration. Inhibition of Notch signaling further potentiated supporting cell proliferation and HC differentiation that occurred spontaneously. The absence of new HCs in the neomycin ears was correlated to less robust Wnt pathway activation, but the ears subjected to neomycin treatment nonetheless showed increased cell division and HC differentiation after subsequent forced upregulation of β-catenin. These studies suggest, first, that Wnt signaling plays a key role in regeneration, and, second, that the outcome of a regenerative response to damage in the newborn cochlea is determined by reaching a threshold level of Wnt signaling rather than its complete absence or presence. Sensory HCs of the inner ear do not regenerate in the adult, and their loss is a major cause of deafness. We found that HCs regenerated spontaneously in the newborn mouse after diphtheria toxin (DT)-induced, but not neomycin-induced, HC death. Regeneration depended on activation of Wnt signaling, and regeneration in DT-treated ears correlated to a higher level of Wnt activation than occurred in nonregenerating neomycin-treated ears. This is significant because insufficient

  3. Bisphosphonate-Linked TrkB Agonist: Cochlea-Targeted Delivery of a Neurotrophic Agent as a Strategy for the Treatment of Hearing Loss.

    Science.gov (United States)

    Kempfle, Judith S; Nguyen, Kim; Hamadani, Christine; Koen, Nicholas; Edge, Albert S; Kashemirov, Boris A; Jung, David H; McKenna, Charles E

    2018-04-18

    Hearing loss affects more than two-thirds of the elderly population, and more than 17% of all adults in the U.S. Sensorineural hearing loss related to noise exposure or aging is associated with loss of inner ear sensory hair cells (HCs), cochlear spiral ganglion neurons (SGNs), and ribbon synapses between HCs and SGNs, stimulating intense interest in therapies to regenerate synaptic function. 7,8-Dihydroxyflavone (DHF) is a selective and potent agonist of tropomyosin receptor kinase B (TrkB) and protects the neuron from apoptosis. Despite evidence that TrkB agonists can promote survival of SGNs, local delivery of drugs such as DHF to the inner ear remains a challenge. We previously demonstrated in an animal model that a fluorescently labeled bisphosphonate, 6-FAM-Zol, administered to the round window membrane penetrated the membrane and diffused throughout the cochlea. Given their affinity for bone mineral, including cochlear bone, bisphosphonates offer an intriguing modality for targeted delivery of neurotrophic agents to the SGNs to promote survival, neurite outgrowth, and, potentially, regeneration of synapses between HCs and SGNs. The design and synthesis of a bisphosphonate conjugate of DHF (Ris-DHF) is presented, with a preliminary evaluation of its neurotrophic activity. Ris-DHF increases neurite outgrowth in vitro, maintains this ability after binding to hydroxyapatite, and regenerates synapses in kainic acid-damaged cochlear organ of Corti explants dissected in vitro with attached SGNs. The results suggest that bisphosphonate-TrkB agonist conjugates have promise as a novel approach to targeted delivery of drugs to treat sensorineural hearing loss.

  4. Desulfurization sorbent regeneration

    Science.gov (United States)

    Jalan, V.M.; Frost, D.G.

    1982-07-07

    A spent solid sorbent resulting from the removal of hydrogen sulfide from a fuel gas flow is regenerated with a steam-air mixture. The mixture of steam and air may also include additional nitrogen or carbon dioxide. The gas mixture contacts the spent sorbent containing metal sulfide at a temperature above 500/sup 0/C to regenerate the sulfide to metal oxide or carbonate. Various metal species including the period four transition metals and the lanthanides are suitable sorbents that may be regenerated by this method. In addition, the introduction of carbon dioxide gas permits carbonates such as those of strontium, barium and calcium to be regenerated. The steam permits regeneration of spent sorbent without formation of metal sulfate. Moreover, the regeneration will proceed with low oxygen concentrations and will occur without the increase in temperature to minimize the risk of sintering and densification of the sorbent. This method may be used for high-temperature fuel cells.

  5. Carcass Management During Avian Influenza Outbreaks

    Science.gov (United States)

    This page on Avian Influenza (AI) describes carcass management during Avian Flu outbreaks, including who oversees carcass management, how they're managed, environmental concerns from carcass management, and disinfection. The page also describes what AI is.

  6. Avian mycoplasmosis update

    Directory of Open Access Journals (Sweden)

    ER Nascimento

    2005-03-01

    Full Text Available Avian mycoplasmas occur in a variety of bird species. The most important mycoplasmas for chickens and turkeys are Mycoplasma gallisepticum (MG, M. synoviae (MS, and M. meleagridis. Besides, M. iowe (MI is an emerging pathogen in turkeys, but of little concern for chickens. Mycoplasmas are bacteria that lack cell wall and belong to the class Mollicutes. Although they have been considered extracellular agents, scientists admit nowadays that some of them are obligatory intracellular microorganisms, whereas all other mycoplasmas are considered facultative intracellular organisms. Their pathogenic mechanism for disease include adherence to host target cells, mediation of apoptosis, innocent bystander damage to host cell due to intimate membrane contact, molecular (antigen mimicry that may lead to tolerance, and mitotic effect for B and/or T lymphocytes, which could lead to suppressed T-cell function and/or production of cytotoxic T cell, besides mycoplasma by-products, such as hydrogen peroxide and superoxide radicals. Moreover, mycoplasma ability to stimulate macrophages, monocytes, T-helper cells and NK cells, results in the production of substances, such as tumor necrosing factor (TNF-alpha, interleukin (IL-1, 2, 6 and interferon (a, b, g. The major clinical signs seen in avian mycoplasmosis are coughing, sneezing, snicks, respiratory rales, ocular and nasal discharge, decreased feed intake and egg production, increased mortality, poor hatchability, and, primarily in turkeys, swelling of the infraorbital sinus(es. Nevertheless, chronic and unapparent infections are most common and more threatening. Mycoplasmas are transmitted horizontally, from bird to bird, and vertically, from dam to offspring through the eggs. Losses attributed to mycoplasmosis, mainly MG and MS infections, result from decreased egg production and egg quality, poor hatchability (high rate of embryonic mortality and culling of day-old birds, poor feed efficiency, increase in

  7. Noise stimulation decreases the concentration of norepinephrine in the rat cochlea.

    Science.gov (United States)

    Vicente-Torres, M A; Gil-Loyzaga, P

    1999-05-14

    The present study was designed to analyze, by using high performance liquid chromatography (HPLC), the effect of acoustic stimulation on the cochlear concentration of norepinephrine (NE). Independently of the rat strain (Long-Evans or Wistar strains), NE concentration decreased about 18% when animals were exposed to white noise (90 dB SPL for 1 h). The same decrease was observed in animals perfused by aortic pathway to remove the blood, indicating that this decrease corresponds exclusively to a neurophysiological process. In fact, these findings could indicate that noise stimulation is involved in the NE release from sympathetic fibers innervating the cochlea. This likely release of NE supports that sympathetic fibers play a functional role in cochleae exposed to noisy situations.

  8. Caloric restriction suppresses apoptotic cell death in the mammalian cochlea and leads to prevention of presbycusis.

    Science.gov (United States)

    Someya, Shinichi; Yamasoba, Tatsuya; Weindruch, Richard; Prolla, Tomas A; Tanokura, Masaru

    2007-10-01

    Presbycusis is characterized by an age-related progressive decline of auditory function, and arises mainly from the degeneration of hair cells or spiral ganglion (SG) cells in the cochlea. Here we show that caloric restriction suppresses apoptotic cell death in the mouse cochlea and prevents late onset of presbycusis. Calorie restricted (CR) mice, which maintained body weight at the same level as that of young control (YC) mice, retained normal hearing and showed no cochlear degeneration. CR mice also showed a significant reduction in the number of TUNEL-positive cells and cleaved caspase-3-positive cells relative to middle-age control (MC) mice. Microarray analysis revealed that CR down-regulated the expression of 24 apoptotic genes, including Bak and Bim. Taken together, our findings suggest that loss of critical cells through apoptosis is an important mechanism of presbycusis in mammals, and that CR can retard this process by suppressing apoptosis in the inner ear tissue.

  9. Mechanisms of Sensorineural Cell Damage, Death and Survival in the Cochlea

    Directory of Open Access Journals (Sweden)

    Allen Frederic Ryan

    2015-04-01

    Full Text Available The majority of acquired hearing loss, including presbycusis, is caused by irreversible damage to the sensorineural tissues of the cochlea. This article reviews the intracellular mechanisms that contribute to sensorineural damage in the cochlea, as well as the survival signaling pathways that can provide endogenous protection and tissue rescue. These data have primarily been generated in hearing loss not directly related to age. However, there is evidence that similar mechanisms operate in presbycusis. Moreover, accumulation of damage from other causes can contribute to age-related hearing loss. Potential therapeutic interventions to balance opposing but interconnected cell damage and survival pathways, such as antioxidants, anti-apoptotics, and pro-inflammatory cytokine inhibitors, are also discussed.

  10. SIMULATION OF A COCHLEA OF AN INTERIOR EAR OF THE HUMAN

    Directory of Open Access Journals (Sweden)

    S. A. Naida

    2012-12-01

    Full Text Available There was conducted the simulations of a cochlea of an interior ear of the human by means of a long line. The following regularities of operation of a cochlea were determined: without the count of flexibilities Reissner's and basilar membranes swing pressure on walls of a cochlear course does not exceed 3,6 % from pressure in the field of an oval window; allocation of a differential of sound pressure fluctuates in a time with frequency; taking into account the slenderness of a membrane and dependence of a standing of resonances from f are spotted by non-uniformity of a basilar membrane; the differential travelling wave exists only near to a resonance on each  frequency where the amplitude buildup of oscillations to a maximum happens for many continuances of resonance frequency. Small relative meaning of range of pressure of travelling wave could become the parent of that Peterson's and Bogert's work has not had the further evolution.

  11. Effects on auditory-nerve fibers of opening the otic capsule at the apex of the chinchilla cochlea

    Science.gov (United States)

    Recio-Spinoso, Alberto; Temchin, Andrei N.; Ruggero, Mario A.

    2015-12-01

    Vibration responses to clicks measured at the apex of chinchilla cochleae with open otic capsules have onsets much shorter than those of responses of auditory-nerve fibers (ANFs) corrected for synaptic and neural delays. Apical vibration responses to tones in open cochleae also differ in other respects from the responses to tones of ANFs with low characteristic frequency (CF) in normal chinchilla cochleae. To further specify the origin(s) of these differences, we recorded from chinchilla ANFs after delicately opening a small hole in the otic capsule overlying scala vestibuli in the cochlear apex. In those cochleae, the earliest ANF responses to clicks are often evoked by condensation (rather than rarefaction) clicks and responses to tones often exhibit level-dependent phase changes different from those in normal cochleae. These findings are largely consistent with, and seem to account for, apical vibration responses of cochleae with open otic capsules. An unexpected finding is that the tuning curves of ANFs with moderately high CF and normal CF thresholds often had hypersensitive tails.

  12. Effects of obesity on protein kinase C, brain creatine kinase, transcription, and autophagy in cochlea.

    Science.gov (United States)

    Hwang, Juen-Haur

    2017-06-01

    Diet-induced obesity (DIO) has been shown to exacerbate hearing degeneration via increased hypoxia, inflammatory responses, and cell loss via both caspase-dependent and caspase-independent apoptosis signaling pathways. This study aimed to investigate the effects of DIO on the mRNA expressions of protein kinase c-β (PKC-β), brain creatine kinase (CKB), transcription modification genes, and autophagy-related genes in the cochlea of CD/1 mice. Sixteen 4-week-old male CD/1 mice were randomly divided into 2 groups. For 16 weeks, the DIO group was fed a high fat diet (60% kcal fat) and the controls were fed a standard diet. Morphometry, biochemistry, auditory brainstem response thresholds, omental fat, and histopathology of the cochlea were compared. Results showed that body weight, body length, body-mass index, omental fat, plasma triglyceride, and auditory brainstem response thresholds were significantly elevated in the DIO group compared with those of the control group. The ratio of vessel wall thickness to radius in the stria vascularis was significantly higher in the DIO group. The cell densities in the spiral ganglion, but not in the spiral prominence, of the cochlea were significantly lower in the DIO group. The expression of histone deacetylation gene 1 (HDAC1) was significantly higher in the DIO group than the control group. However, the expressions of PKC-β, CKB, HDAC3, histone acetyltransferase gene (P300), lysosome-associated membrane protein 2 (Lamp2), and light chain 3 (Lc3) genes were not significantly different between two groups. These results suggest that DIO might exacerbate hearing degeneration possibly via increased HDAC1 gene expression in the cochlea of CD/1 mice.

  13. [Effects of electroacupuncture on cochlea morphology and expression of aquaporins in guinea pigs with endolymphatic hydrops].

    Science.gov (United States)

    Jiang, Liyuan; Wang, Canjun; Ni, Fangying; Chen, Huade

    2015-06-01

    To observe the effects of electroacupuncture (EA) on cochlea morphology and expression of aquaporin 1 (AQP1) in guinea pigs with endolymphatic hydrops, so as to explore the possible mechanism of EA on endolymphatic hydrops. Forty guinea pigs were randomly divided into a blank group, a model group, a medication group and an EA group, 10 guinea pigs in each one. Model of endolymphatic hydrops was established by using intraperitoneal injection of aldosterone. Guinea pigs in the blank group and model group were treated with identical immobilization as EA group but no treatment was given; guinea pigs in the medication group were treated with intragastric administration of hydrochlorothiazide at a dose of 5 mg/kg, once a day for consecutive 10 days; guinea pigs in the EA group were treated with' EA at "Baihui" (GV 20) and "Tinggong"(SI 19), once a day for consecutive 10 days. The serum ionic concentration in each group was tested by turbidimetric method; hematoxylin-eosin staining was used to measure the severity of cochlea hydrops; immunohistochemical method was used to observe the expression of AQP1 in the cochlea. (1) There was no endolymphatic hydrops in the blank group, moderate-severe endolymphatic hydrops in the model group and slight endolymphatic hydrops in the EA group and medication group. (2) The concentration of K+ and Ca2+ in the EA group was higher than that in the model group and medication group (all P0. 05). (3) The ratio of expression area of AQP1 in the model group was lower than that in the blank group (P0. 05). EA could relieve the endolymphatic hydrops in guinea pigs; the mechanism is likely to be related with up-regulating the expression of AQP1 in cochlea and ion concentration might be an important factor involved.

  14. The Coda of the Transient Response in a Sensitive Cochlea: A Computational Modeling Study.

    Directory of Open Access Journals (Sweden)

    Yizeng Li

    2016-07-01

    Full Text Available In a sensitive cochlea, the basilar membrane response to transient excitation of any kind-normal acoustic or artificial intracochlear excitation-consists of not only a primary impulse but also a coda of delayed secondary responses with varying amplitudes but similar spectral content around the characteristic frequency of the measurement location. The coda, sometimes referred to as echoes or ringing, has been described as a form of local, short term memory which may influence the ability of the auditory system to detect gaps in an acoustic stimulus such as speech. Depending on the individual cochlea, the temporal gap between the primary impulse and the following coda ranges from once to thrice the group delay of the primary impulse (the group delay of the primary impulse is on the order of a few hundred microseconds. The coda is physiologically vulnerable, disappearing when the cochlea is compromised even slightly. The multicomponent sensitive response is not yet completely understood. We use a physiologically-based, mathematical model to investigate (i the generation of the primary impulse response and the dependence of the group delay on the various stimulation methods, (ii the effect of spatial perturbations in the properties of mechanically sensitive ion channels on the generation and separation of delayed secondary responses. The model suggests that the presence of the secondary responses depends on the wavenumber content of a perturbation and the activity level of the cochlea. In addition, the model shows that the varying temporal gaps between adjacent coda seen in experiments depend on the individual profiles of perturbations. Implications for non-invasive cochlear diagnosis are also discussed.

  15. Noise-induced nitrotyrosine increase and outer hair cell death in guinea pig cochlea.

    Science.gov (United States)

    Han, Wei-ju; Shi, Xiao-rui; Nuttall, Alfred

    2013-01-01

    Modern research has provided new insights into the biological mechanisms of noise-induced hearing loss, and a number of studies showed the appearance of increased reactive oxygen species (ROS) and reactive nitrogen species (RNS) during and after noise exposure. This study was designed to investigate the noise exposure induced nitrotyrosine change and the mechanism of outer hair cells death in guinea pig cochlea. Thirty guinea pigs were used in this study. The experimental animals were either exposed for 4 hours per day to broadband noise at 122 dB SPL (A-weighted) for 2 consecutive days or perfused cochleae with 5 mg/ml of the SIN1 solutions, an exogenous NO and superoxide donor, for 30 minutes. Then the cochleae of the animals were dissected. Propidium iodide (PI), a DNA intercalating fluorescent probe, was used to trace morphological changes in OHC nuclei. The distribution of nitrotyrosine (NT) in the organ of Corti and the cochlear lateral wall tissue from the guinea pigs were examined using fluorescence immunohistochemistry method. Whole mounts of organ of Corti were prepared. Morphological and fluorescent changes were examined under a confocal microscope. Either after noise exposure or after SIN1 perfusion, outer hair cells (OHCs) death with characteristics of both apoptotic and necrotic degradation appeared. Nitrotyrosine immunolabeling could be observed in the OHCs from the control animals. After noise exposure, NT immunostaining became much greater than the control animals in OHCs. The apoptotic OHC has significant increase of nitrotyrosine in and around the nucleus following noise exposure. In the normal later wall of cochleae, relatively weak nitrotyrosine immunolabeling could be observed. After noise exposure, nitrotyrosine immunoactivity became stronger in stria vascularis. Noise exposure induced increase of nitrotyrosine production is associated with OHCs death suggesting reactive nitrogen species participation in the cochlear pathophysiology of noise

  16. Comparison of doses received in the mandibular condyle, cochlea, and parotid gland in neuroaxial treatment

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Fernanda L.; Lima, Fabiana F. de; Vilela, Eudice, E-mail: fluoliveira@gmail.com [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Fo, Joao Antonio, E-mail: jaf@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear

    2015-07-01

    Sensorineural hearing loss is a common side effect in patients who undergo radiotherapy for the treatment of cancer tumors in the head and neck. In fractioned doses of radiotherapy, in the majority of intracranial tumors, the cochlea is the most affected organ. In addition to the cochlea, the mandible and the parotid glands are also exposed to radiation, which commonly leads to Osteoradionecrosis of the mandible and Xerostomia. In the head and neck regions, this can be complicated by the semi-independence of the positioning in this region, as regards the rigid cranium, connected to the semi-rigid mandible, and successive levels of the upper cervical spine and thoracic spine, which can lead to uncertainty in rotation as well as in head-neck movements, both up and down and side to side. The present study performed an intercomparison of the doses applied through four radiotherapy planning techniques for the neuro axial regions of the cochlea, mandible, and parotid glands, considering the changes carried out in each planning technique, including the protective shield, the angulations gantry and the field size. The results obtained by applying the half beam and angled field techniques varied in the cochlea by an average of 113.8% from the prescribed dose, whereas when applying the angled field technique with and without the mobile gap, the results varied in 104.5%. In the mandible, the half beam and angled field techniques showed that the dose varied an average of 16.5%, while in the techniques with and without the mobile gap, the variation showed an average of 116.4%. These values were also received by the parotid glands, which overlap the mandible. It can therefore be concluded that the protection shields of the first two techniques were less efficient in protecting the mandible due to its modeling. (author)

  17. Current situation on highly pathogenic avian influenza

    Science.gov (United States)

    Avian influenza is one of the most important diseases affecting the poultry industry worldwide. Avian influenza viruses can cause a range of clinical disease in poultry. Viruses that cause severe disease and mortality are referred to as highly pathogenic avian influenza (HPAI) viruses. The Asian ...

  18. Markov Chain Estimation of Avian Seasonal Fecundity

    Science.gov (United States)

    To explore the consequences of modeling decisions on inference about avian seasonal fecundity we generalize previous Markov chain (MC) models of avian nest success to formulate two different MC models of avian seasonal fecundity that represent two different ways to model renestin...

  19. 77 FR 34783 - Highly Pathogenic Avian Influenza

    Science.gov (United States)

    2012-06-12

    ... [Docket No. APHIS-2006-0074] RIN 0579-AC36 Highly Pathogenic Avian Influenza AGENCY: Animal and Plant... regions where any subtype of highly pathogenic avian influenza (HPAI) is considered to exist. The interim... avian influenza (HPAI). On January 24, 2011, we published in the Federal Register (76 FR 4046-4056...

  20. An overview on avian influenza

    Directory of Open Access Journals (Sweden)

    Nelson Rodrigo da Silva Martins

    2012-06-01

    Full Text Available Avian influenza (AI is considered an exotic disease in the Brazilian poultry industry, according to the National Avian Health Program (PNSA, with permanent monitoring of domestic, exotic and native avian species. Brazil presents privileged environmental conditions of reduced risk. In addition, all commercial poultry and conservation holdings are registered in state or national inventories and geographically located (GPS for health control. Poultry health standards are adopted for the conformity to the international market, mostly for the intensified poultry destined for exportation, but also for companion exotic and native conservation facilities. Guidelines for monitoring and the diagnosis of AI are published by the PNSA and follow the standards proposed by the international health code (World Organization for Animal Health, Organization International des Epizooties - OIE and insure the free of status for avian influenza virus (AIV of LPAIV-low pathogenicity AIV and HPAIV-high pathogenicity AIV. In addition, the infections by mesogenic and velogenic Newcastle disease virus, Mycoplasma gallisepticum, M. synoviae and M. meleagridis, Salmonella enteric subspecies enterica serovar Gallinarum biovars Gallinarum and Pullorum are eradicated from reproduction. Controlled infections by S.enterica subspecies enterica serovars Enteritidis and Typhimurium are monitored for breeders. The vaccination of chickens in ovo or at hatch against Marek's disease is mandatory. Broiler production is an indoor activity, confinement which insures biosecurity, with safe distances from the potential AIV reservoir avian species. Worldwide HPAIV H5N1 notifications to the OIE, in March 2011, included 51 countries.

  1. Avian influenza viruses in humans.

    Science.gov (United States)

    Malik Peiris, J S

    2009-04-01

    Past pandemics arose from low pathogenic avian influenza (LPAI) viruses. In more recent times, highly pathogenic avian influenza (HPAI) H5N1, LPAI H9N2 and both HPAI and LPAI H7 viruses have repeatedly caused zoonotic disease in humans. Such infections did not lead to sustained human-to-human transmission. Experimental infection of human volunteers and seroepidemiological studies suggest that avian influenza viruses of other subtypes may also infect humans. Viruses of the H7 subtype appear to have a predilection to cause conjunctivitis and influenza-like illness (ILI), although HPAI H7N7 virus has also caused fatal respiratory disease. Low pathogenic H9N2 viruses have caused mild ILI and its occurrence may be under-recognised for this reason. In contrast, contemporary HPAI H5N1 viruses are exceptional in their virulence for humans and differ from human seasonal influenza viruses in their pathogenesis. Patients have a primary viral pneumonia progressing to acute respiratory distress syndrome (ARDS) and multiple organ dysfunction syndrome. Over 380 human cases have been confirmed to date, with an overall case fatality of 63%. The zoonotic transmission of avian influenza is a rare occurrence, butthe greater public health concern is the adaptation of such viruses to efficient human transmission, which could lead to a pandemic. A better understanding of the ecology of avian influenza viruses and the biological determinants of transmissibility and pathogenicity in humans is important for pandemic preparedness.

  2. On the stability and compressive nonlinearity of a physiologically based model of the cochlea

    Energy Technology Data Exchange (ETDEWEB)

    Nankali, Amir [Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan (United States); Grosh, Karl [Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan (United States); Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan (United States)

    2015-12-31

    Hearing relies on a series of coupled electrical, acoustical (fluidic) and mechanical interactions inside the cochlea that enable sound processing. A positive feedback mechanism within the cochlea, called the cochlear amplifier, provides amplitude and frequency selectivity in the mammalian auditory system. The cochlear amplifier and stability are studied using a nonlinear, micromechanical model of the Organ of Corti (OoC) coupled to the electrical potentials in the cochlear ducts. It is observed that the mechano-electrical transduction (MET) sensitivity and somatic motility of the outer hair cell (OHC), control the cochlear stability. Increasing MET sensitivity beyond a critical value, while electromechanical coupling coefficient is within a specific range, causes instability. We show that instability in this model is generated through a supercritical Hopf bifurcation. A reduced order model of the system is approximated and it is shown that the tectorial membrane (TM) transverse mode effect on the dynamics is significant while the radial mode can be simplified from the equations. The cochlear amplifier in this model exhibits good agreement with the experimental data. A comprehensive 3-dimensional model based on the cross sectional model is simulated and the results are compared. It is indicated that the global model qualitatively inherits some characteristics of the local model, but the longitudinal coupling along the cochlea shifts the stability boundary (i.e., Hopf bifurcation point) and enhances stability.

  3. Effect of erythropoietin on acoustically traumatized rat cochlea: an immunohistochemical study.

    Science.gov (United States)

    Gürgen, Oğuzhan; Gürgen, Seren Gülşen; Kirkim, Günay; Kolatan, Efsun; Gürkan, Selhan; Güvenç, Yeşim; Eskiizmir, Görkem

    2014-08-01

    To investigate the audiological and histopathological effects of erythropoietin on acoustic overstimulation in rats. Twenty-two male Wistar albino rats were divided into 3 groups: sham group (n = 7), erythropoietin injection group (n = 8), and saline injection group (n = 7). Both erythropoietin and saline injection groups were exposed to white noise (100 decibel [dB] sound pressure level [SPL]) for 3 hours. Auditory brainstem responses were measured before, immediately after, and on the 7th day of noise exposure. All animals were sacrificed on the 7th day and temporal bones were collected. The serial sections of the cochleae were stained by caspase-3 and caspase-9 immunostaining and by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) method in order to detect apoptotic cells. In the saline group statistically significant differences were detected between the baseline and immediate postacoustic overstimulation thresholds of click and 6 kHz stimuli. However, when the baseline and immediate postacoustic overstimulation thresholds of click and 6 kHz stimuli were compared in the erythropoietin injection group, no statistically significant difference was determined. Histopathologic evaluations demonstrated that erythropoietin decreased the amount of apoptotic cells in the cochlea. Erythropoietin is likely to prevent the acute threshold changes and decrease the amount of apoptosis in cochlea after acoustic overstimulation in rats.

  4. Vibration induced hearing loss in guinea pig cochlea: expression of TNF-alpha and VEGF.

    Science.gov (United States)

    Zou, Jing; Pyykkö, Ilmari; Sutinen, Päivi; Toppila, Esko

    2005-04-01

    Transcranial vibration was applied for seven animals at a frequency of 250 Hz for 15 min, and five animals were used as normal controls to investigate cellular and molecular mechanism linked to vibration-induced hearing loss in animal model. Compound action potential (CAP) thresholds were measured by round window niche electrode. The expression of tumour necrosis factor alpha (TNF-alpha) and its receptors (TNF R1, TNF R2), vascular endothelium growth factor (VEGF) and its receptors (VEGF R1, VEGF R2) were analysed by immunohistochemistry. Transcranial vibration caused expression of TNF-alpha, TNF R1 and TNF R2 in the cochlea and the expression of TNF R2 was stronger than that of TNF R1. Vibration also induced VEGF and VEGF R2 expression in the cochlea. The average immediate hearing loss was 62 dB and after three days still 48 dB. It is concluded that transcranial vibration as during temporal bone drilling produces cochlear shear stress that is connected with up-regulation of TNF-alpha and its receptors. Also VEGF and VEGF R2 are up-regulated. These responses may be linked to both the damage and repair process of the cochlea.

  5. Localization of (/sup 3/H). gamma. -aminobutyric acid in the cochlea. Light and electron microscopic autoradiography

    Energy Technology Data Exchange (ETDEWEB)

    Richrath, W; Kraus, H; Fromme, H G [Muenster Univ. (F.R. Germany). Hals-, Nasen- und Ohrenklinik; Muenster Univ. (F.R. Germany). Inst. fuer Medizinische Physik)

    1974-01-01

    In guinea pigs, 1 h after intraarterial and local administration of /sup 3/H-GABA, autoradiographs of the cochlea and the brain were performed. As a parameter of distribution of this substance, silver grain density was examined by means of light and electron microscopy. Intraarterial injection was not followed by any activity neither in brain nor in the cochlea, an observation suggesting the existence of a blood-perilymph barrier additional to the blood-brain barrier. Perfusion of the cochlea produced a marked activity in the spiral ganglion. Different from other tritium labelled amino acids, /sup 3/H-GABA activity could be found only in glia cells but not in nerve cell bodies or axons. The significance of this finding is open to question. In the organ of Corti a selective labelling of efferent nerve fibres could be found by means of light microscopy, additionally, using electron microscopy, only efferent synapses proved to be labelled. Most of silver grains were attached to vesicles and mitochondria, some grains to the synaptie deft. Afferent synapses remained unlabelled. Comparing with publications concerning GABA localization and concentration in the brain, we conclude that the efferent system of the Organ of Corti contains a high concentration of GABA. As present electrophysiological results are contradictory the GABA distribution alone gives no convincing evidence that this substance may serve as a transmitter.

  6. On marginal regeneration

    NARCIS (Netherlands)

    Stein, H.N.

    1991-01-01

    On applying the marginal regeneration concept to the drainage of free liquid films, problems are encountered: the films do not show a "neck" of minimum thickness at the film/border transition; and the causes of the direction dependence of the marginal regeneration are unclear. Both problems can be

  7. Sonic hedgehog initiates cochlear hair cell regeneration through downregulation of retinoblastoma protein

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Na [Otology Skull Base Surgery Department, Hearing Research Institute, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai 200031 (China); Department of Otolaryngology and Program in Neuroscience, Harvard Medical School and Eaton Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA 02114 (United States); Chen, Yan [Central Laboratory, Hearing Research Institute, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai 200031 (China); Wang, Zhengmin [Otology Skull Base Surgery Department, Hearing Research Institute, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai 200031 (China); Institute of Biomedical Sciences, Fudan University, Shanghai 200032 (China); Chen, Guoling [Otology Skull Base Surgery Department, Hearing Research Institute, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai 200031 (China); Lin, Qin [Otology Skull Base Surgery Department, Hearing Research Institute, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai 200031 (China); Department of Otolaryngology, First Affiliated Hospital of Fujian Medical University, Otolaryngology Institute of Fujian Province, Fuzhou (China); Chen, Zheng-Yi, E-mail: Zheng-yi_chen@meei.harvard.edu [Department of Otolaryngology and Program in Neuroscience, Harvard Medical School and Eaton Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA 02114 (United States); Li, Huawei, E-mail: hwli@shmu.edu.cn [Otology Skull Base Surgery Department, Hearing Research Institute, Eye and ENT Hospital of Shanghai Medical School, Fudan University, Shanghai 200031 (China); Institute of Biomedical Sciences, Fudan University, Shanghai 200032 (China)

    2013-01-11

    Highlights: Black-Right-Pointing-Pointer Shh activation in neonatal cochleae enhances sensory cell proliferation. Black-Right-Pointing-Pointer Proliferating supporting cells can transdifferentiate into hair cells. Black-Right-Pointing-Pointer Shh promotes proliferation by transiently modulating pRb activity. Black-Right-Pointing-Pointer Shh inhibits pRb by inhibiting transcription and increasing phosphorylation of pRb. -- Abstract: Cell cycle re-entry by cochlear supporting cells and/or hair cells is considered one of the best approaches for restoring hearing loss as a result of hair cell damage. To identify mechanisms that can be modulated to initiate cell cycle re-entry and hair cell regeneration, we studied the effect of activating the sonic hedgehog (Shh) pathway. We show that Shh signaling in postnatal rat cochleae damaged by neomycin leads to renewed proliferation of supporting cells and hair cells. Further, proliferating supporting cells are likely to transdifferentiate into hair cells. Shh treatment leads to inhibition of retinoblastoma protein (pRb) by increasing phosphorylated pRb and reducing retinoblastoma gene transcription. This results in upregulation of cyclins B1, D2, and D3, and CDK1. These results suggest that Shh signaling induces cell cycle re-entry in cochlear sensory epithelium and the production of new hair cells, in part by attenuating pRb function. This study provides an additional route to modulate pRb function with important implications in mammalian hair cell regeneration.

  8. Sonic hedgehog initiates cochlear hair cell regeneration through downregulation of retinoblastoma protein

    International Nuclear Information System (INIS)

    Lu, Na; Chen, Yan; Wang, Zhengmin; Chen, Guoling; Lin, Qin; Chen, Zheng-Yi; Li, Huawei

    2013-01-01

    Highlights: ► Shh activation in neonatal cochleae enhances sensory cell proliferation. ► Proliferating supporting cells can transdifferentiate into hair cells. ► Shh promotes proliferation by transiently modulating pRb activity. ► Shh inhibits pRb by inhibiting transcription and increasing phosphorylation of pRb. -- Abstract: Cell cycle re-entry by cochlear supporting cells and/or hair cells is considered one of the best approaches for restoring hearing loss as a result of hair cell damage. To identify mechanisms that can be modulated to initiate cell cycle re-entry and hair cell regeneration, we studied the effect of activating the sonic hedgehog (Shh) pathway. We show that Shh signaling in postnatal rat cochleae damaged by neomycin leads to renewed proliferation of supporting cells and hair cells. Further, proliferating supporting cells are likely to transdifferentiate into hair cells. Shh treatment leads to inhibition of retinoblastoma protein (pRb) by increasing phosphorylated pRb and reducing retinoblastoma gene transcription. This results in upregulation of cyclins B1, D2, and D3, and CDK1. These results suggest that Shh signaling induces cell cycle re-entry in cochlear sensory epithelium and the production of new hair cells, in part by attenuating pRb function. This study provides an additional route to modulate pRb function with important implications in mammalian hair cell regeneration.

  9. Avian reproductive physiology

    Science.gov (United States)

    Gee, G.F.; Gibbons, Edward F.; Durrant, Barbara S.; Demarest, Jack

    1995-01-01

    Knowledge of the many physiological factors associated with egg production , fertility, incubation, and brooding in nondomestic birds is limited. Science knows even less about reproduction in most of the 238 endangered or threatened birds. This discussion uses studies of nondomestic and, when necessary, domestic birds to describe physiological control of reproduction. Studies of the few nondomestic avian species show large variation in physiological control of reproduction. Aviculturists, in order to successfully propagate an endangered bird, must understand the bird's reproductive peculiarities. First, investigators can do studies with carefully chosen surrogate species, but eventually they need to confirm the results in the target endangered bird. Studies of reproduction in nondomestic birds increased in the last decade. Still, scientists need to do more comparative studies to understand the mechanisms that control reproduction in birds. New technologies are making it possible to study reproductive physiology of nondomestic species in less limiting ways. These technologies include telemetry to collect information without inducing stress on captives (Howey et al., 1987; Klugman, 1987), new tests for most of the humoral factors associated with reproduction, and the skill to collect small samples and manipulate birds without disrupting the physiological mechanisms (Bercovitz et al., 1985). Managers are using knowledge from these studies to improve propagation in zoological parks, private and public propagation facilities, and research institutions. Researchers need to study the control of ovulation, egg formation, and oviposition in the species of nondomestic birds that lay very few eggs in a season, hold eggs in the oviduct for longer intervals, or differ in other ways from the more thoroughly studied domestic birds. Other techniques that would enhance propagation for nondomestlc birds include tissue culture of cloned embryonic cells, cryopreservation of embryos

  10. Control strategies against avian influenza

    Science.gov (United States)

    Since 1959, 40 epizootics of high pathogenicity avian influenza (HPAI) have occurred (Figure 1). Thirty-five of these epizootic HPAI viruses were geographically-limited (mostly to single countries), involved farm-to-farm spread and were eradicated from poultry by stamping-out programs; i.e. the HPAI...

  11. Avian metapneumovirus in the USA

    Science.gov (United States)

    In the United States of America (USA), avian metapneumovirus (aMPV) causes an upper respiratory tract infection in turkeys; no outbreaks have been reported in commercial chicken flocks. Typical clinical signs of the disease in turkey poults include coughing, sneezing, nasal discharge, tracheal rale...

  12. Reverse genetics of avian metapneumoviruses

    Science.gov (United States)

    An overview of avian metapneumovirus (aMPV) infection in turkeys and development of a reverse genetics system for aMPV subgroup C (aMPV-C) virus will be presented. By using reverse genetics technology, we generated recombinant aMPV-C viruses containing a different length of glycoprotein (G) gene or...

  13. Helping the Retina Regenerate

    Science.gov (United States)

    ... the retina News Brief 03/30/17 A new report gives recommendations for regenerating retinal ganglion cells (RGCs), crucial neurons in the back of the eye that carry visual information to the brain. Authored ...

  14. Adeno-associated virus transformation into the normal miniature pig and the normal guinea pigs cochlea via scala tympani.

    Science.gov (United States)

    Shi, Xunbei; Wu, Nan; Zhang, Yue; Guo, Weiwei; Lin, Chang; Yang, Shiming

    2017-09-01

    To investigate the expression of the miniature pig cochlea after AAV1 transfect into the cochlea via round window membrane (RWM). Twenty miniature pigs are equally divided into four experimental groups. Twelve miniature pigs are equally divided into four control groups. Each pig was transfected with the AAV1 in the experimental group via RWM and each pig was transduced with the artificial perilymph in the control group. The expression of green fluorescent protein (GFP) was observed at 2 weeks, 3 weeks and 4 weeks, respectively. Likewise, AAV1 was delivered into the guinea pigs cochleas using the same method, and the results were compared with that of the miniature pigs. The expression was mainly in the inner hair cells of the miniature pig. The expression of GFP began to appear at 2 weeks, reached the peak at 3 weeks. It also expressed in Hensen's cells, inner pillar cells, outer pillar cells, spiral limbus, and spiral ligament. In the meanwhile, AAV1 was delivered into guinea pig cochlea via the same method, and AAV1 was also expressed in the inner hair cells. But the expression peaked at 2 weeks, and the efficiency of the inner hair cell transfection was higher than that of the pig. AAV1 can be transformed into miniature pig cochlea via scala tympani by the RWM method efficiently.

  15. The rat cochlea in the absence of circulating adrenal hormones: an electrophysiological and morphological study.

    Science.gov (United States)

    Lohuis, P J; Börjesson, P K; Klis, S F; Smoorenburg, G F

    2000-05-01

    Circulating adrenal hormones affect strial function. Removal of endogenous levels of adrenal steroids by bilateral adrenalectomy (ADX) in rats causes a decrease of Na(+)/K(+)-ATPase activity in the cochlear lateral wall [Rarey et al., 1989. Arch. Otolaryngol. Head Neck Surg. 115, 817-821] and a decrease of the volume of the marginal cells in the stria vascularis [Lohuis et al., 1990. Acta Otolaryngol. (Stockh.) 110, 348-356]. To study further the effect of absence of circulating adrenocorticosteroids on cochlear function, 18 male Long Evans rats underwent either an ADX or a SHAM operation. Electrocochleography was performed 1 week after surgery for tone bursts in a frequency range of 1-16 kHz. Thereafter, the cochleas were harvested and examined histologically. No significant changes in the amplitude growth curves of the summating potential (SP), the compound action potential (CAP) and the cochlear microphonics (CM) were detected after ADX. However, visually, there appeared to be a decrease of endolymphatic volume (tentatively called imdrops). Reissner's membrane (RM) extended less into scala vestibuli in ADX animals than in SHAM-operated animals. The ratio between the length of RM and the straight distance between the medial and lateral attachment points of RM were used as an objective measure to quantify this effect in each sub-apical half turn of the cochlea. The decrease in length of RM was statistically significant. Thus, circulating adrenal hormones appear to be necessary for normal cochlear fluid homeostasis. Absence of one or more of these hormones leads to shrinkage of the scala media (imdrops). However, the absence of adrenal hormones does not affect the gross cochlear potentials. Apparently, the cochlea is capable of compensating for the absence of circulating adrenal hormones to sustain the conditions necessary for proper cochlear transduction.

  16. Avian disease at the Salton Sea

    Science.gov (United States)

    Friend, M.

    2002-01-01

    A review of existing records and the scientific literature was conducted for occurrences of avian diseases affecting free-ranging avifauna within the Salton Sea ecosystem. The period for evaluation was 1907 through 1999. Records of the U.S. Department of Agriculture, Bureau of Biological Survey and the scientific literature were the data sources for the period of 1907a??1939. The narrative reports of the U.S. Fish and Wildlife Service's Sonny Bono National Wildlife Refuge Complex and the epizootic database of the U.S. Geological Survey's National Wildlife Health Center were the primary data sources for the remainder of the evaluation. The pattern of avian disease at the Salton Sea has changed greatly over time. Relative to past decades, there was a greater frequency of major outbreaks of avian disease at the Salton Sea during the 1990s than in previous decades, a greater variety of disease agents causing epizootics, and apparent chronic increases in the attrition of birds from disease. Avian mortality was high for about a decade beginning during the mid-1920s, diminished substantially by the 1940s and was at low to moderate levels until the 1990s when it reached the highest levels reported. Avian botulism (Clostridium botulinum type C) was the only major cause of avian disease until 1979 when the first major epizootic of avian cholera (Pasteurella multocidia) was documented. Waterfowl and shorebirds were the primary species affected by avian botulism. A broader spectrum of species have been killed by avian cholera but waterfowl have suffered the greatest losses. Avian cholera reappeared in 1983 and has joined avian botulism as a recurring cause of avian mortality. In 1989, avian salmonellosis (Salmonella typhimurium) was first diagnosed as a major cause of avian disease within the Salton Sea ecosystem and has since reappeared several times, primarily among cattle egrets (Bubulcus ibis). The largest loss from a single epizootic occurred in 1992, when an estimated

  17. Spontaneous hair cell regeneration in the mouse utricle following gentamicin ototoxicity.

    Science.gov (United States)

    Kawamoto, Kohei; Izumikawa, Masahiko; Beyer, Lisa A; Atkin, Graham M; Raphael, Yehoash

    2009-01-01

    Whereas most epithelial tissues turn-over and regenerate after a traumatic lesion, this restorative ability is diminished in the sensory epithelia of the inner ear; it is absent in the cochlea and exists only in a limited capacity in the vestibular epithelium. The extent of regeneration in vestibular hair cells has been characterized for several mammalian species including guinea pig, rat, and chinchilla, but not yet in mouse. As the fundamental model species for investigating hereditary disease, the mouse can be studied using a wide variety of genetic and molecular tools. To design a mouse model for vestibular hair cell regeneration research, an aminoglycoside-induced method of complete hair cell elimination was developed in our lab and applied to the murine utricle. Loss of utricular hair cells was observed using scanning electron microscopy, and corroborated by a loss of fluorescent signal in utricles from transgenic mice with GFP-positive hair cells. Regenerative capability was characterized at several time points up to six months following insult. Using scanning electron microscopy, we observed that as early as two weeks after insult, a few immature hair cells, demonstrating the characteristic immature morphology indicative of regeneration, could be seen in the utricle. As time progressed, larger numbers of immature hair cells could be seen along with some mature cells resembling surface morphology of type II hair cells. By six months post-lesion, numerous regenerated hair cells were present in the utricle, however, neither their number nor their appearance was normal. A BrdU assay suggested that at least some of the regeneration of mouse vestibular hair cells involved mitosis. Our results demonstrate that the vestibular sensory epithelium in mice can spontaneously regenerate, elucidate the time course of this process, and identify involvement of mitosis in some cases. These data establish a road map of the murine vestibular regenerative process, which can be

  18. Avian fruit preferences across a Puerto Rican forested landscape: pattern consistency and implications for seed removal.

    Science.gov (United States)

    Carlo, Tomás A; Collazo, Jaime A; Groom, Martha J

    2003-01-01

    Avian fruit consumption may ensure plant reproductive success when frugivores show consistent preference patterns and effectively remove and disperse seeds. In this study we examined avian fruit preferences and their seed-removal services at five study sites in north-central Puerto Rico. At each site, we documented the diet of seven common fruit-eating avian species from February to September 1998. Using foraging observations and area-based estimates of fruit abundance, we examined preference patterns of birds. We found that 7 out of 68 fleshy-fruited plant species were responsible for most of the fruit diet of birds. Seventeen plant species were preferred and four of them were repeatedly preferred across several study sites and times by at least one avian species. Preferred plant species comprised a small percentage of fleshy fruits at each site (musica and Vireo altiloquous, removed most of the seeds of plants for which they exhibited repeated preference across the landscape. Preference patterns, particularly those exhibiting consistency in space and time for plant species having prolonged fruiting periods, may have important mechanistic consequences for the persistence, succession, and regeneration of tropical plant communities.

  19. Avian fruit preferences across a Puerto Rican forested landscape: Pattern consistency and implications for seed removal

    Science.gov (United States)

    Carlo, T.A.; Collazo, J.A.; Groom, Martha J.

    2003-01-01

    Avian fruit consumption may ensure plant reproductive success when frugivores show consistent preference patterns and effectively remove and disperse seeds. In this study we examined avian fruit preferences and their seed-removal services at five study sites in north-central Puerto Rico. At each site, we documented the diet of seven common fruit-eating avian species from February to September 1998. Using foraging observations and area-based estimates of fruit abundance, we examined preference patterns of birds. We found that 7 out of 68 fleshy-fruited plant species were responsible for most of the fruit diet of birds. Seventeen plant species were preferred and four of them were repeatedly preferred across several study sites and times by at least one avian species. Preferred plant species comprised a small percentage of fleshy fruits at each site (plants at some locations than species exhibiting constancy in their patterns of preference. Only two frugivores, Euphonia musica and Vireo altiloquous, removed most of the seeds of plants for which they exhibited repeated preference across the landscape. Preference patterns, particularly those exhibiting consistency in space and time for plant species having prolonged fruiting periods, may have important mechanistic consequences for the persistence, succession, and regeneration of tropical plant communities.

  20. Evidence-Based Advances in Avian Medicine.

    Science.gov (United States)

    Summa, Noémie M; Guzman, David Sanchez-Migallon

    2017-09-01

    This article presents relevant advances in avian medicine and surgery over the past 5 years. New information has been published to improve clinical diagnosis in avian diseases. This article also describes new pharmacokinetic studies. Advances in the understanding and treatment of common avian disorders are presented in this article, as well. Although important progress has been made over the past years, there is still much research that needs to be done regarding the etiology, pathophysiology, diagnosis, and treatment of avian diseases and evidence-based information is still sparse in the literature. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Nonlinear dynamics of avian influenza epidemic models.

    Science.gov (United States)

    Liu, Sanhong; Ruan, Shigui; Zhang, Xinan

    2017-01-01

    Avian influenza is a zoonotic disease caused by the transmission of the avian influenza A virus, such as H5N1 and H7N9, from birds to humans. The avian influenza A H5N1 virus has caused more than 500 human infections worldwide with nearly a 60% death rate since it was first reported in Hong Kong in 1997. The four outbreaks of the avian influenza A H7N9 in China from March 2013 to June 2016 have resulted in 580 human cases including 202 deaths with a death rate of nearly 35%. In this paper, we construct two avian influenza bird-to-human transmission models with different growth laws of the avian population, one with logistic growth and the other with Allee effect, and analyze their dynamical behavior. We obtain a threshold value for the prevalence of avian influenza and investigate the local or global asymptotical stability of each equilibrium of these systems by using linear analysis technique or combining Liapunov function method and LaSalle's invariance principle, respectively. Moreover, we give necessary and sufficient conditions for the occurrence of periodic solutions in the avian influenza system with Allee effect of the avian population. Numerical simulations are also presented to illustrate the theoretical results. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Perfluorodecalin and bone regeneration

    Directory of Open Access Journals (Sweden)

    F Tamimi

    2013-01-01

    Full Text Available Perfluorodecalin (PFD is a chemically and biologically inert biomaterial and, as many perfluorocarbons, is also hydrophobic, radiopaque and has a high solute capacity for gases such as oxygen. In this article we have demonstrated, both in vitro and in vivo, that PFD may significantly enhance bone regeneration. Firstly, the potential benefit of PFD was demonstrated by prolonging the survival of bone marrow cells cultured in anaerobic conditions. These findings translated in vivo, where PFD incorporated into bone-marrow-loaded 3D-printed scaffolds substantially improved their capacity to regenerate bone. Secondly, in addition to biological applications, we have also shown that PFD improves the radiopacity of bone regeneration biomaterials, a key feature required for the visualisation of biomaterials during and after surgical implantation. Finally, we have shown how the extreme hydrophobicity of PFD enables the fabrication of highly cohesive self-setting injectable biomaterials for bone regeneration. In conclusion, perfluorocarbons would appear to be highly beneficial additives to a number of regenerative biomaterials, especially those for bone regeneration.

  3. Using EGEE against avian flu

    CERN Multimedia

    2006-01-01

    During April 2006 avian flu was spreading across the world with the potential of turning into a pandemic, a drug to treat the deadly H5N1 strain was needed. Such a task required the huge processing power provided by EGEE, which analysed 300 000 possible drug components for their suitability. This map shows the network of computer centres and their activity during this time.

  4. Protein transduction therapy into cochleae via the round window niche in guinea pigs

    Directory of Open Access Journals (Sweden)

    Hiroki Takeda

    2016-01-01

    Full Text Available Cell-penetrating peptides (CPPs are short sequences of amino acids that facilitate the penetration of conjugated cargoes across mammalian cell membranes, and as such, they may provide a safe and effective method for drug delivery to the inner ear. Simple polyarginine peptides have been shown to induce significantly higher cell penetration rates among CPPs. Herein, we show that a peptide consisting of nine arginines (“9R” effectively delivered enhanced green fluorescent protein (EGFP into guinea pig cochleae via the round window niche without causing any deterioration in auditory function. A second application, 24 hours after the first, prolonged the presence of EGFP. To assess the feasibility of protein transduction using 9R-CPPs via the round window, we used “X-linked inhibitor of apoptosis protein” (XIAP bonded to a 9R peptide (XIAP-9R. XIAP-9R treatment prior to acoustic trauma significantly reduced putative hearing loss and the number of apoptotic hair cells loss in the cochleae. Thus, the topical application of molecules fused to 9R-CPPs may be a simple and promising strategy for treating inner ear diseases.

  5. Response to a pure tone in a nonlinear mechanical-electrical-acoustical model of the cochlea.

    Science.gov (United States)

    Meaud, Julien; Grosh, Karl

    2012-03-21

    In this article, a nonlinear mathematical model is developed based on the physiology of the cochlea of the guinea pig. The three-dimensional intracochlear fluid dynamics are coupled to a micromechanical model of the organ of Corti and to electrical potentials in the cochlear ducts and outer hair cells (OHC). OHC somatic electromotility is modeled by linearized piezoelectric relations whereas the OHC hair-bundle mechanoelectrical transduction current is modeled as a nonlinear function of the hair-bundle deflection. The steady-state response of the cochlea to a single tone is simulated in the frequency domain using an alternating frequency time scheme. Compressive nonlinearity, harmonic distortion, and DC shift on the basilar membrane (BM), tectorial membrane (TM), and OHC potentials are predicted using a single set of parameters. The predictions of the model are verified by comparing simulations to available in vivo experimental data for basal cochlear mechanics. In particular, the model predicts more amplification on the reticular lamina (RL) side of the cochlear partition than on the BM, which replicates recent measurements. Moreover, small harmonic distortion and DC shifts are predicted on the BM, whereas more significant harmonic distortion and DC shifts are predicted in the RL and TM displacements and in the OHC potentials. Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  6. Effect of 60Co gamma irradiation on cochlea function and structure in guinea pigs

    International Nuclear Information System (INIS)

    Wang Zhonghe; Cai Yilin; Hu Haisen

    1994-01-01

    In the experiment inner ears of guinea pigs were irradiated with 60 Co gamma rays using the method of simulated clinical routine irradiation in order to find the effects of ionizing radiation on the cochlea function and structure and to explore the mechanism and protective measure that lead to hearing impairment following radiotherapy to the head and neck of cancer patients. Ten weeks after irradiation it was found that ABR threshold increased with increasing dose of radiation. The mean values of ABR thresholds in 70 Gy and 90 Gy groups were 10 dB and 28 dB respectively. The number of inner and outer hair cell and pillar cell loss was counted under microscope. The number of lost cells increased with increasing dose of radiation. The severity of damage in morphology of inner, outer hair cells and pillar cells reduced progressively. The groups of 70 Gy and 90 Gy lost significantly more than groups of control and 50 Gy(P<0.05). It is concluded that the damage of hair cells of cochlea is the direct result of gamma ray irradiation of the inner ear and is the main cause of hearing impairment following irradiation

  7. Involvement of p53 and Bcl-2 in sensory cell degeneration in aging rat cochleae.

    Science.gov (United States)

    Xu, Yang; Yang, Wei Ping; Hu, Bo Hua; Yang, Shiming; Henderson, Donald

    2017-06-01

    p53 and Bcl-2 (B-cell lymphoma 2) are involved in the process of sensory cell degeneration in aging cochleae. To determine molecular players in age-related hair cell degeneration, this study examined the changes in p53 and Bcl-2 expression at different stages of apoptotic and necrotic death of hair cells in aging rat cochleae. Young (3-4 months) and aging (23-24 months) Fisher 344/NHsd rats were used. The thresholds of the auditory brainstem response (ABR) were measured to determine the auditory function. Immunolabeling was performed to determine the expression of p53 and Bcl-2 proteins in the sensory epithelium. Propidium iodide staining was performed to determine the morphologic changes in hair cell nuclei. Aging rats exhibited a significant elevation in ABR thresholds at all tested frequencies (p aging hair cells showing the early signs of apoptotic changes in their nuclei. The Bcl-2 expression increase was also observed in hair cells displaying early signs of necrosis. As the hair cell degenerative process advanced, p53 and Bcl-2 immunoreactivity became reduced or absent. In the areas where no detectable nuclear staining was present, p53 and Bcl-2 immunoreactivity was absent.

  8. Inner ear injury caused by air intrusion to the scala vestibuli of the cochlea.

    Science.gov (United States)

    Kobayashi, T; Sakurada, T; Ohyama, K; Takasaka, M

    1993-11-01

    In a previous communication, we demonstrated that the introduction of air into the scala tympani of the cochlea causes a decrease of cochlear potentials; however, the change in endocochlear dc potential (EP) was mild and the decreased cochlear microphonics (CM) and compound action potentials (CAP) were, at least partially, reversible. In contrast, we have now found that air perfusion (3-60 microliters/min) in the scala vestibuli decreased cochlear potentials more drastically than that in the scala tympani. The change in the EP after air perfusion in the scala vestibuli was characterized by a decrease of the negative EP in response to anoxia. The CM drastically decreased upon the initiation of air perfusion and no recovery was observed after refilling of the perilymph. Histological examination showed collapse of Reissner's membrane in 12 out of 17 cochleas examined. The extent and frequency of the collapse increased with an increase in the amount of air perfused in the scala vestibuli. As the minimal amount of air needed to cause inner ear damage by air perfusion in the scala vestibuli is as small as 3 microliters, it is possible that the prognosis is worse in cases with fistula of the oval window compared to that of the round window area, if the pneumolabyrinth is involved in the pathophysiology of perilymphatic fistula. It is also indicated that air inflation of the middle ear is dangerous in cases with fistula in the oval window.

  9. A second, low-frequency mode of vibration in the intact mammalian cochlea.

    Science.gov (United States)

    Lukashkin, Andrei N; Russell, Ian J

    2003-03-01

    The mammalian cochlea is a structure comprising a number of components connected by elastic elements. A mechanical system of this kind is expected to have multiple normal modes of oscillation and associated resonances. The guinea pig cochlear mechanics was probed using distortion components generated in the cochlea close to the place of overlap between two tones presented simultaneously. Otoacoustic emissions at frequencies of the distortion components were recorded in the ear canal. The phase behavior of the emissions reveals the presence of a nonlinear resonance at a frequency about a half octave below that of the high-frequency primary tone. The location of the resonance is level dependent and the resonance shifts to lower frequencies with increasing stimulus intensity. This resonance is thought to be associated with the tectorial membrane. The resonance tends to minimize input to the cochlear receptor cells at frequencies below the high-frequency primary and increases the dynamic load to the stereocilia of the receptor cells at the primary frequency when the tectorial membrane and reticular lamina move in counterphase.

  10. The cochlea of the enigmatic pygmy right whale Caperea marginata informs mysticete phylogeny.

    Science.gov (United States)

    Park, Travis; Marx, Felix G; Fitzgerald, Erich M G; Evans, Alistair R

    2017-06-01

    The pygmy right whale, Caperea marginata, is the least understood extant baleen whale (Cetacea, Mysticeti). Knowledge on its basic anatomy, ecology, and fossil record is limited, even though its singular position outside both balaenids (right whales) and balaenopteroids (rorquals + grey whales) gives Caperea a pivotal role in mysticete evolution. Recent investigations of the cetacean cochlea have provided new insights into sensory capabilities and phylogeny. Here, we extend this advance to Caperea by describing, for the first time, the inner ear of this enigmatic species. The cochlea is large and appears to be sensitive to low-frequency sounds, but its hearing limit is relatively high. The presence of a well-developed tympanal recess links Caperea with cetotheriids and balaenopteroids, rather than balaenids, contrary to the traditional morphological view of a close Caperea-balaenid relationship. Nevertheless, a broader sample of the cetotheriid Herpetocetus demonstrates that the presence of a tympanal recess can be variable at the specific and possibly even the intraspecific level. © 2017 Wiley Periodicals, Inc.

  11. Computed tomography measurements of the normal and the pathologic cochlea in children

    International Nuclear Information System (INIS)

    Teissier, Natacha; Abbeele, Thierry van den; Sebag, Guy; Elmaleh-Berges, Monique

    2010-01-01

    Radiological investigation is frequently undertaken to assess the aetiology of sensorineural hearing loss (SNHL). To establish the CT measurements of the normal cochlea in children and to determine radiological criteria correlated with SNHL. A retrospective study of temporal bone CT performed in 159 children, age range from 3 days to 16 years between February 1999 and July 2004. A control group (n = 88) comprised children without SNHL; the SNHL group comprised 71 children. The width of the second turn of the cochlea (CW), the cochlear height (CH), and the width of the bony canal for the cochlear nerve (WCN) were measured on a reference plane containing the modiolus, the posterior semicircular canal, the footplate, and the stapes arch. Width of the canal measurements ≤1.7 mm or ≥2.5 mm supported the diagnosis of SNHL with a specificity of 97% and 91%, respectively. Cochlear width was found to be significantly smaller in the SNHL group (5.61 ± 0.51 mm) than in the control group (5.75 ± 0.31 mm, P < 0.02), a size <5.4 mm being highly suggestive of SNHL with a specificity of 90%. No significant variations of all measurements were found with age. Appropriate measurements of WCN and CW are highly correlated with SNHL. (orig.)

  12. Communication analysis for feedback control of civil infrastructure using cochlea-inspired sensing nodes

    Science.gov (United States)

    Peckens, Courtney A.; Cook, Ireana; Lynch, Jerome P.

    2016-04-01

    Wireless sensor networks (WSNs) have emerged as a reliable, low-cost alternative to the traditional wired sensing paradigm. While such networks have made significant progress in the field of structural monitoring, significantly less development has occurred for feedback control applications. Previous work in WSNs for feedback control has highlighted many of the challenges of using this technology including latency in the wireless communication channel and computational inundation at the individual sensing nodes. This work seeks to overcome some of those challenges by drawing inspiration from the real-time sensing and control techniques employed by the biological central nervous system and in particular the mammalian cochlea. A novel bio-inspired wireless sensor node was developed that employs analog filtering techniques to perform time-frequency decomposition of a sensor signal, thus encompassing the functionality of the cochlea. The node then utilizes asynchronous sampling of the filtered signal to compress the signal prior to communication. This bio-inspired sensing architecture is extended to a feedback control application in order to overcome the traditional challenges currently faced by wireless control. In doing this, however, the network experiences high bandwidths of low-significance information exchange between nodes, resulting in some lost data. This study considers the impact of this lost data on the control capabilities of the bio-inspired control architecture and finds that it does not significantly impact the effectiveness of control.

  13. Dose-dependent effects of ouabain on spiral ganglion neurons and Schwann cells in mouse cochlea.

    Science.gov (United States)

    Zhang, Zhi-Jian; Guan, Hong-Xia; Yang, Kun; Xiao, Bo-Kui; Liao, Hua; Jiang, Yang; Zhou, Tao; Hua, Qing-Quan

    2017-10-01

    This study aimed in fully investigating the toxicities of ouabain to mouse cochlea and the related cellular environment, and providing an optimal animal model system for cell transplantation in the treatment of auditory neuropathy (AN) and sensorineural hearing loss (SNHL). Different dosages of ouabain were applied to mouse round window. The auditory brainstem responses and distortion product otoacoustic emissions were used to evaluate the cochlear function. The immunohistochemical staining and cochlea surface preparation were performed to detect the spiral ganglion neurons (SGNs), Schwann cells and hair cells. Ouabain at the dosages of 0.5 mM, 1 mM and 3 mM selectively and permanently destroyed SGNs and their functions, while leaving the hair cells relatively intact. Ouabain at 3 mM resulted in the most severe SGNs loss and induced significant loss of Schwann cells started as early as 7 days and with further damages at 14 and 30 days after ouabain exposure. The application of ouabain to mouse round window induces damages of SGNs and Schwann cells in a dose- and time-dependent manner, this study established a reliable and accurate animal model system of AN and SNHL.

  14. Avian Egg and Egg Coat.

    Science.gov (United States)

    Okumura, Hiroki

    2017-01-01

    An ovulated egg of vertebrates is surrounded by unique extracellular matrix, the egg coat or zona pellucida, playing important roles in fertilization and early development. The vertebrate egg coat is composed of two to six zona pellucida (ZP) glycoproteins that are characterized by the evolutionarily conserved ZP-domain module and classified into six subfamilies based on phylogenetic analyses. Interestingly, investigations of biochemical and functional features of the ZP glycoproteins show that the roles of each ZP-glycoprotein family member in the egg-coat formation and the egg-sperm interactions seemingly vary across vertebrates. This might be one reason why comprehensive understandings of the molecular basis of either architecture or physiological functions of egg coat still remain elusive despite more than 3 decades of intensive investigations. In this chapter, an overview of avian egg focusing on the oogenesis are provided in the first section, and unique features of avian egg coat, i.e., perivitelline layer, including the morphology, biogenesis pathway, and physiological functions are discussed mainly on chicken and quail in terms of the characteristics of ZP glycoproteins in the following sections. In addition, these features of avian egg coat are compared to mammalian zona pellucida, from the viewpoint that the structural and functional varieties of ZP glycoproteins might be associated with the evolutionary adaptation to their reproductive strategies. By comparing the egg coat of birds and mammals whose reproductive strategies are largely different, new insights into the molecular mechanisms of vertebrate egg-sperm interactions might be provided.

  15. Avian zoonoses – a review

    Directory of Open Access Journals (Sweden)

    Kozdruń Wojciech

    2015-06-01

    Full Text Available Birds are one of the most interesting and most colourful groups of animals, but they can also be a source of zoonotic factors dangerous for humans. This paper describes the threats to human health from contact with birds. The most vulnerable occupational groups associated with birds are veterinarians, owners of poultry farms, breeders of ornamental birds, zoo personnel, and poultry slaughterhouse workers. Ornithosis is the most dangerous zoonosis of the avian bacterial diseases. Among other hazardous bacterial factors, Salmonella and Campylobacter are responsible for gastrointestinal diseases. Avian influenza is the most dangerous of the viral diseases. It should be noted, however, that avian influenza is a disease of birds, not humans. The recent threat which has appeared is infection with West Nile virus. The results of serological examinations of birds and humans indicate that the virus exists in our ecosystem. Allergic alveolitis connected with the pigeon tick and the Dermanyssus gallinae mite also merits mention. In any case, where people have contact with birds or their droppings and secretions, special precautions should be taken. This way the negative effects of birds on human health can be minimised or eliminated

  16. Supercritical fluid regeneration of adsorbents

    Science.gov (United States)

    Defilippi, R. P.; Robey, R. J.

    1983-05-01

    The results of a program to perform studies supercritical (fluid) carbon dioxide (SCF CO2) regeneration of adsorbents, using samples of industrial wastewaters from manufacturing pesticides and synthetic solution, and to estimate the economics of the specific wastewater treatment regenerations, based on test data are given. Processing costs for regenerating granular activated carbon GAC) for treating industrial wastewaters depend on stream properties and regeneration throughput.

  17. MANAGING AVIAN FLU, CARCASS MANAGEMENT & BIOSOLIDS

    Science.gov (United States)

    The avian influenza virus is discussed with emphasis on the impact to poultry and possible movement of the highly pathogenic H5N 1 virus to humans. A review is made of the worldwide effects to date of the avian influenza viruses; methods for the viruses to enter recreational wate...

  18. Seasonality, distribution and taxonomic status of avian ...

    African Journals Online (AJOL)

    Description of a new species is based upon morphology of gametocyte development in the peripheral blood of the avian host. This does not distinguish between morphologically identical gametocytes from different avian host families, nor is species or family level a valid taxonomic character. Thus, Haemoproteus and ...

  19. Mechanisms of avian songs and calls

    DEFF Research Database (Denmark)

    Larsen, Ole Næsbye

    2008-01-01

    The avian vocal organ, the syrinx, is a specialized structure located rather inaccessibly in an air sac close to the heart where the trachea bifurcates into the two primary bronchi. The syrinx of different avian taxa varies so much in position and morphology that it has been used for taxonomy. It...

  20. Global spread and control of avian influenza

    Science.gov (United States)

    H5 and H7 high pathogenicity avian influenza (HPAI) viruses emerge from the mutation of H5 and H7 low pathogenicity avian influenza viruses (LPAI) after circulation in terrestrial poultry for a few weeks to years. There have been 42 distinct HPAI epizootics since 1959. The largest being the H5N1 A/G...

  1. Avian Influenza: A growing threat to Africa

    Science.gov (United States)

    The H9N2 low pathogenic avian influenza (LPAI) is probably the most widespread avian influenza subtype in poultry around the world being endemic in a large part of Asia, the Middle East, Northern Africa, and in Germany. Currently, there is no standardized clade system to describe the antigenic vari...

  2. Swept source optical coherence tomography for in vivo imaging and vibrometry in the apex of the mouse cochlea

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hee Yoon [E.L. Ginzton Laboratory and Department of Electrical Engineering, Stanford University, Stanford, California (United States); Department of Otolaryngology-Head and Neck Surgery, Stanford University, Stanford, California (United States); Raphael, Patrick D.; Oghalai, John S. [Department of Otolaryngology-Head and Neck Surgery, Stanford University, Stanford, California (United States); Ellerbee, Audrey K. [E.L. Ginzton Laboratory and Department of Electrical Engineering, Stanford University, Stanford, California (United States); Applegate, Brian E. [Department of Biomedical Engineering, Texas A& M University, College Station, Texas (United States)

    2015-12-31

    Cochlear amplification has been most commonly investigated by measuring the vibrations of the basilar membrane in animal models. Several different techniques have been used for measuring these vibrations such as laser Doppler vibrometry, miniature pressure sensors, low coherence interferometry, and spectral-domain optical coherence tomography (SD-OCT). We have built a swept-source OCT (SS-OCT) system, which is similar to SD-OCT in that it is capable of performing both imaging and vibration measurements within the mouse cochlea in vivo without having to open the bone. In vivo 3D images of a mouse cochlea were obtained, and the basilar membrane, tectorial membrane, Reissner’s membrane, tunnel of Corti, and reticular lamina could all be resolved. We measured vibrations of multiple structures within the mouse cochlea to sound stimuli. As well, we measured the radial deflections of the reticular lamina and tectorial membrane to estimate the displacement of the outer hair cell stereocilia. These measurements have the potential to more clearly define the mechanisms underlying the linear and non-linear processes within the mammalian cochlea.

  3. The mechanisms underlying multiple lobes in SOAE suppression tuning curves in a transmission line model of the cochlea

    DEFF Research Database (Denmark)

    Epp, Bastian; Manley, Geoff; van Dijk, Pim

    2018-01-01

    ]. In the present study, a nonlinear and active transmission line model of the cochlea is used to investigate this hypothesis. The model is able to produce SOAEs with plausible characteristics and further shows the suggested standing wave pattern. This approach hence makes it possible to disentangle contributions...

  4. Ethanol extract of Piper longum L. attenuates gentamicin-induced hair cell loss in neonatal cochlea cultures.

    Science.gov (United States)

    Du, Xiao Fei; Song, Jae-Jun; Hong, Seungug; Kim, Jihye

    2012-06-01

    Piper longum L. (PL), also as known as long pepper, a well-known spice and traditional medicine in Asia and Pacific islands, has been reported to exhibit wide spectrum activity including antioxidant activity. However, little information is available on its protective effect on gentamicin (GM) induced ototoxicity which is commonly regarded as being mediated by reactive oxygen species and reactive nitrogen species. This study was undertaken to investigate the protective effect of PL ethanol extract on gentamicin-induced hair cell loss in neonatal cochlea cultures. Cochlea cultures from postnatal day 2-3 mice were used for analysis of the protective effects of PL against gentamicin-induced hair cell loss by phalloidin staining. E. coil cultures were used to determine whether PL interferes with the antibiotic activity of GM. Nitric oxide (NO)-scavenging activity of PL was also measured in vitro. GM induced significant dose-dependent hair cell loss in cochlea cultures. However, without interfering with the antibiotic activity of GM, PL showed a significant and concentration-dependent protective effect against GM-induced hair cell loss, and hair cells retained their stereocilia well. In addition, PL expressed direct scavenging activity toward NO radical liberated within solution of sodium nitroprusside. These findings demonstrate the protective effect of PL on GM-induced hair cell loss in neonatal cochlea cultures, and suggest that it might be of therapeutic benefit for treatment of GM-induced ototoxicity.

  5. Blood circulation of the inner ear under the influence of medications. Radiotracer experiments using guinea pig cochlea

    International Nuclear Information System (INIS)

    Neumeier, A.

    1987-01-01

    The dependence of the blood circulation in the inner ear on various medications is discussed. By means of a radiotracer clearance technique the cochlear clearance curves for the guinea pig cochlea after the administration of various circulation stimulants were determined. (MBC) [de

  6. An active magnetic regenerator device

    DEFF Research Database (Denmark)

    2015-01-01

    A rotating active magnetic regenerator (AMR) device comprising two or more regenerator beds, a magnet arrangement and a valve arrangement. The valve arrangement comprises a plurality of valve elements arranged substantially immovably with respect to the regenerator beds along a rotational direction...

  7. Infection and Pulp Regeneration

    Directory of Open Access Journals (Sweden)

    Sahng G. Kim

    2016-03-01

    Full Text Available The regeneration of the pulp-dentin complex has been a great challenge to both scientists and clinicians. Previous work has shown that the presence of prior infection may influence the characteristics of tissues formed in the root canal space after regenerative endodontic treatment. The formation of ectopic tissues such as periodontal ligament, bone, and cementum has been observed in the root canal space of immature necrotic teeth with apical periodontitis, while the regeneration of dentin and pulp has been identified in previously non-infected teeth. The current regenerative endodontic therapy utilizes disinfection protocols, which heavily rely on chemical irrigation using conventional disinfectants. From a microbiological point of view, the current protocols may not allow a sufficiently clean root canal microenvironment, which is critical for dentin and pulp regeneration. In this article, the significance of root canal disinfection in regenerating the pulp-dentin complex, the limitations of the current regenerative endodontic disinfection protocols, and advanced disinfection techniques designed to reduce the microorganisms and biofilms in chronic infection are discussed.

  8. Sox10 expressing cells in the lateral wall of the aged mouse and human cochlea.

    Directory of Open Access Journals (Sweden)

    Xinping Hao

    Full Text Available Age-related hearing loss (presbycusis is a common human disorder, affecting one in three Americans aged 60 and over. Previous studies have shown that presbyacusis is associated with a loss of non-sensory cells in the cochlear lateral wall. Sox10 is a transcription factor crucial to the development and maintenance of neural crest-derived cells including some non-sensory cell types in the cochlea. Mutations of the Sox10 gene are known to cause various combinations of hearing loss and pigmentation defects in humans. This study investigated the potential relationship between Sox10 gene expression and pathological changes in the cochlear lateral wall of aged CBA/CaJ mice and human temporal bones from older donors. Cochlear tissues prepared from young adult (1-3 month-old and aged (2-2.5 year-old mice, and human temporal bone donors were examined using quantitative immunohistochemical analysis and transmission electron microscopy. Cells expressing Sox10 were present in the stria vascularis, outer sulcus and spiral prominence in mouse and human cochleas. The Sox10(+ cell types included marginal and intermediate cells and outer sulcus cells, including those that border the scala media and those extending into root processes (root cells in the spiral ligament. Quantitative analysis of immunostaining revealed a significant decrease in the number of Sox10(+ marginal cells and outer sulcus cells in aged mice. Electron microscopic evaluation revealed degenerative alterations in the surviving Sox10(+ cells in aged mice. Strial marginal cells in human cochleas from donors aged 87 and older showed only weak immunostaining for Sox10. Decreases in Sox10 expression levels and a loss of Sox10(+ cells in both mouse and human aged ears suggests an important role of Sox10 in the maintenance of structural and functional integrity of the lateral wall. A loss of Sox10(+ cells may also be associated with a decline in the repair capabilities of non-sensory cells in the

  9. Stimulating endogenous cardiac regeneration

    Directory of Open Access Journals (Sweden)

    Amanda eFinan

    2015-09-01

    Full Text Available The healthy adult heart has a low turnover of cardiac myocytes. The renewal capacity, however, is augmented after cardiac injury. Participants in cardiac regeneration include cardiac myocytes themselves, cardiac progenitor cells, and peripheral stem cells, particularly from the bone marrow compartment. Cardiac progenitor cells and bone marrow stem cells are augmented after cardiac injury, migrate to the myocardium, and support regeneration. Depletion studies of these populations have demonstrated their necessary role in cardiac repair. However, the potential of these cells to completely regenerate the heart is limited. Efforts are now being focused on ways to augment these natural pathways to improve cardiac healing, primarily after ischemic injury but in other cardiac pathologies as well. Cell and gene therapy or pharmacological interventions are proposed mechanisms. Cell therapy has demonstrated modest results and has passed into clinical trials. However, the beneficial effects of cell therapy have primarily been their ability to produce paracrine effects on the cardiac tissue and recruit endogenous stem cell populations as opposed to direct cardiac regeneration. Gene therapy efforts have focused on prolonging or reactivating natural signaling pathways. Positive results have been demonstrated to activate the endogenous stem cell populations and are currently being tested in clinical trials. A potential new avenue may be to refine pharmacological treatments that are currently in place in the clinic. Evidence is mounting that drugs such as statins or beta blockers may alter endogenous stem cell activity. Understanding the effects of these drugs on stem cell repair while keeping in mind their primary function may strike a balance in myocardial healing. To maximize endogenous cardiac regeneration,a combination of these approaches couldameliorate the overall repair process to incorporate the participation ofmultiple cell players.

  10. Three-dimensional hard and soft tissue imaging of the human cochlea by scanning laser optical tomography (SLOT.

    Directory of Open Access Journals (Sweden)

    Nadine Tinne

    Full Text Available The present study focuses on the application of scanning laser optical tomography (SLOT for visualization of anatomical structures inside the human cochlea ex vivo. SLOT is a laser-based highly efficient microscopy technique which allows for tomographic imaging of the internal structure of transparent specimens. Thus, in the field of otology this technique is best convenient for an ex vivo study of the inner ear anatomy. For this purpose, the preparation before imaging comprises decalcification, dehydration as well as optical clearing of the cochlea samples in toto. Here, we demonstrate results of SLOT imaging visualizing hard and soft tissue structures with an optical resolution of down to 15 μm using extinction and autofluorescence as contrast mechanisms. Furthermore, the internal structure can be analyzed nondestructively and quantitatively in detail by sectioning of the three-dimensional datasets. The method of X-ray Micro Computed Tomography (μCT has been previously applied to explanted cochlea and is solely based on absorption contrast. An advantage of SLOT is that it uses visible light for image formation and thus provides a variety of contrast mechanisms known from other light microscopy techniques, such as fluorescence or scattering. We show that SLOT data is consistent with μCT anatomical data and provides additional information by using fluorescence. We demonstrate that SLOT is applicable for cochlea with metallic cochlear implants (CI that would lead to significant artifacts in μCT imaging. In conclusion, the present study demonstrates the capability of SLOT for resolution visualization of cleared human cochleae ex vivo using multiple contrast mechanisms and lays the foundation for a broad variety of additional studies.

  11. Random walks with shape prior for cochlea segmentation in ex vivo μCT

    DEFF Research Database (Denmark)

    Ruiz Pujadas, Esmeralda; Kjer, Hans Martin; Piella, Gemma

    2016-01-01

    Purpose Cochlear implantation is a safe and effective surgical procedure to restore hearing in deaf patients. However, the level of restoration achieved may vary due to differences in anatomy, implant type and surgical access. In order to reduce the variability of the surgical outcomes, we...... propose a new framework for cochlea segmentation in ex vivo μCT images using random walks where a distance-based shape prior is combined with a region term estimated by a Gaussian mixture model. The prior is also weighted by a confidence map to adjust its influence according to the strength of the image...... contour. Random walks is performed iteratively, and the prior mask is aligned in every iteration. Results We tested the proposed approach in ten μCT data sets and compared it with other random walks-based segmentation techniques such as guided random walks (Eslami et al. in Med Image Anal 17...

  12. Differences between mechanical and neural tuning at the apex of the intact guinea pig cochlea

    Science.gov (United States)

    Recio-Spinoso, Alberto; Oghalai, John S.

    2018-05-01

    While most of human speech information is contained within frequencies guinea pig cochlea using volumetric optical coherence tomography vibrometry (VOCTV). We found that vibrations within apical cochlear regions, with neural tuning below 2 kHz, demonstrate low-pass filter characteristics. There was evidence of a low-level of broad-band cochlear amplification that did not sharpen frequency selectivity. We compared the vibratory responses we measured to previously-measured single-unit auditory nerve tuning curves in the same frequency range, and found that mechanical responses do not match neural responses. These data suggest that, for low frequency cochlear regions, inner hair cells not only transduce vibrations of the organ of Corti but also sharpen frequency tuning.

  13. The origins of the cochlea and impedance matching hearing in synapsids

    Directory of Open Access Journals (Sweden)

    Michael Laass

    2016-06-01

    Full Text Available The origin of tympanic hearing in early synapsids is still controversial, because little is known about their inner ear and the function of their sound conducting apparatus. Here I describe the earliest known tympanic ear in the synapsid lineage, the ear of Pristerodon (Therapsida, Anomodontia from the Late Permian of South Africa, which was virtually reconstructed from neutron tomographic data. Although Pristerodon is not a direct ancestor of mammals, its inner ear with distinctive cochlear cavity represents a connecting link between the primitive therapsid inner ear and the mammalian inner ear. The anatomy of the sound conducting apparatus of Pristerodon and the increased sound pressure transformer ratio points to a sensitivity to airborne sound. Furthermore, the origins of the cochlea and impedance matching hearing in synapsids coincided with the loss of contact between head and substrate, which already took place at least in Late Permian therapsids even before the postdentary bones became detached from the mandible.

  14. SU-F-T-392: Superior Brainstem and Cochlea Sparing with VMAT for Glioblastoma Multiforme

    Energy Technology Data Exchange (ETDEWEB)

    Briere, TM; McAleer, MF; Levy, LB; Yang, JN; Anderson, MD [Cancer Ctr., Houston, TX (United States)

    2016-06-15

    Purpose: Volumetric arc therapy (VMAT) can provide similar target coverage and normal tissue sparing as IMRT but with shorter treatment times. At our institution VMAT was adopted for the treatment glioblastoma multiforme (GBM) after a small number of test plans demonstrated its non-inferiority. In this study, we compare actual clinical treatment plans for a larger cohort of patients treated with either VMAT or IMRT. Methods: 90 GBM patients were included in this study, 45 treated with IMRT and 45 with VMAT. All planning target volumes (PTVs) were prescribed a dose of 50 Gy, with a simultaneous integrated boost to 60 Gy. Most IMRT plans used 5 non-coplanar beams, while most VMAT plans used 2 coplanar beams. Statistical analysis was performed using Fisher’s exact test or the Wilcoxon-Mann-Whitney rank sum test. Included in the analysis were patient and treatment characteristics as well as the doses to the target volumes and organs at risk. Results: Treatment times for the VMAT plans were reduced by 5 minutes compared with IMRT. The PTV coverage was similar, with at least 95% covered for all plans, while the median boost PTV dose differed by 0.1 Gy between the IMRT and VMAT cohorts. The doses to the brain, optic chiasm, optic nerves and eyes were not significantly different. The mean dose to the brainstem, however, was 9.4 Gy less with VMAT (p<0.001). The dose to the ipsilateral and contralateral cochleae were respectively 19.7 and 9.5 Gy less (p<0.001). Conclusion: Comparison of clinical treatment plans for separate IMRT and VMAT cohorts demonstrates that VMAT can save substantial treatment time while providing similar target coverage and superior sparing of the brainstem and cochleae. To our knowledge this is the first study to demonstrate this benefit of VMAT in the management of GBM.

  15. Measuring uncertainty in dose delivered to the cochlea due to setup error during external beam treatment of patients with cancer of the head and neck

    Energy Technology Data Exchange (ETDEWEB)

    Yan, M.; Lovelock, D.; Hunt, M.; Mechalakos, J.; Hu, Y.; Pham, H.; Jackson, A., E-mail: jacksona@mskcc.org [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10065 (United States)

    2013-12-15

    Purpose: To use Cone Beam CT scans obtained just prior to treatments of head and neck cancer patients to measure the setup error and cumulative dose uncertainty of the cochlea. Methods: Data from 10 head and neck patients with 10 planning CTs and 52 Cone Beam CTs taken at time of treatment were used in this study. Patients were treated with conventional fractionation using an IMRT dose painting technique, most with 33 fractions. Weekly radiographic imaging was used to correct the patient setup. The authors used rigid registration of the planning CT and Cone Beam CT scans to find the translational and rotational setup errors, and the spatial setup errors of the cochlea. The planning CT was rotated and translated such that the cochlea positions match those seen in the cone beam scans, cochlea doses were recalculated and fractional doses accumulated. Uncertainties in the positions and cumulative doses of the cochlea were calculated with and without setup adjustments from radiographic imaging. Results: The mean setup error of the cochlea was 0.04 ± 0.33 or 0.06 ± 0.43 cm for RL, 0.09 ± 0.27 or 0.07 ± 0.48 cm for AP, and 0.00 ± 0.21 or −0.24 ± 0.45 cm for SI with and without radiographic imaging, respectively. Setup with radiographic imaging reduced the standard deviation of the setup error by roughly 1–2 mm. The uncertainty of the cochlea dose depends on the treatment plan and the relative positions of the cochlea and target volumes. Combining results for the left and right cochlea, the authors found the accumulated uncertainty of the cochlea dose per fraction was 4.82 (0.39–16.8) cGy, or 10.1 (0.8–32.4) cGy, with and without radiographic imaging, respectively; the percentage uncertainties relative to the planned doses were 4.32% (0.28%–9.06%) and 10.2% (0.7%–63.6%), respectively. Conclusions: Patient setup error introduces uncertainty in the position of the cochlea during radiation treatment. With the assistance of radiographic imaging during setup

  16. Bionanomaterials for skin regeneration

    CERN Document Server

    Leonida, Mihaela D

    2016-01-01

    This book gives a concise overview of bionanomaterials with applications for skin regeneration. The advantages and challenges of nanoscale materials are covered in detail, giving a basic view of the skin structure and conditions that require transdermal or topical applications. Medical applications, such as wound healing, care for burns, skin disease, and cosmetic care, such as aging of the skin and photodamage, and how they benefit from bionanomaterials, are described in detail. A final chapter is devoted to the ethical and social issues related to the use of bionanomaterials for skin regeneration. This is an ideal book for researchers in materials science, medical scientists specialized in dermatology, and cosmetic chemists working in formulations. It can also serve as a reference for nanotechnologists, dermatologists, microbiologists, engineers, and polymer chemists, as well as students studying in these fields.

  17. Biomaterials for cardiac regeneration

    CERN Document Server

    Ruel, Marc

    2015-01-01

    This book offers readers a comprehensive biomaterials-based approach to achieving clinically successful, functionally integrated vasculogenesis and myogenesis in the heart. Coverage is multidisciplinary, including the role of extracellular matrices in cardiac development, whole-heart tissue engineering, imaging the mechanisms and effects of biomaterial-based cardiac regeneration, and autologous bioengineered heart valves. Bringing current knowledge together into a single volume, this book provides a compendium to students and new researchers in the field and constitutes a platform to allow for future developments and collaborative approaches in biomaterials-based regenerative medicine, even beyond cardiac applications. This book also: Provides a valuable overview of the engineering of biomaterials for cardiac regeneration, including coverage of combined biomaterials and stem cells, as well as extracellular matrices Presents readers with multidisciplinary coverage of biomaterials for cardiac repair, including ...

  18. Regeneration of Optic Nerve

    Directory of Open Access Journals (Sweden)

    Kwok-Fai So

    2011-05-01

    Full Text Available The optic nerve is part of the central nervous system (CNS and has a structure similar to other CNS tracts. The axons that form the optic nerve originate in the ganglion cell layer of the retina and extend through the optic tract. As a tissue, the optic nerve has the same organization as the white matter of the brain in regard to its glia. There are three types of glial cells: Oligodendrocytes, astrocytes, and microglia. Little structural and functional regeneration of the CNS takes place spontaneously following injury in adult mammals. In contrast, the ability of the mammalian peripheral nervous system (PNS to regenerate axons after injury is well documented. A number of factors are involved in the lack of CNS regeneration, including: (i the response of neuronal cell bodies against the damage; (ii myelin-mediated inhibition by oligodendrocytes; (iii glial scarring, by astrocytes; (iv macrophage infiltration; and (v insufficient trophic factor support. The fundamental difference in the regenerative capacity between CNS and PNS neuronal cell bodies has been the subject of intensive research. In the CNS the target normally conveys a retrograde trophic signal to the cell body. CNS neurons die because of trophic deprivation. Damage to the optic nerve disconnects the neuronal cell body from its target-derived trophic peptides, leading to the death of retinal ganglion cells. Furthermore, the axontomized neurons become less responsive to the peptide trophic signals they do receive. On the other hand, adult PNS neurons are intrinsically responsive to neurotrophic factors and do not lose trophic responsiveness after axotomy. In this talk different strategies to promote optic-nerve regeneration in adult mammals are reviewed. Much work is still needed to resolve many issues. This is a very important area of neuroregeneration and neuroprotection, as currently there is no cure after traumatic optic nerve injury or retinal disease such as glaucoma, which

  19. Avian influenza in shorebirds: experimental infection of ruddy turnstones (Arenaria interpres) with avian influenza virus

    OpenAIRE

    Hall, Jeffrey S.; Krauss, Scott; Franson, J. Christian; TeSlaa, Joshua L.; Nashold, Sean W.; Stallknecht, David E.; Webby, Richard J.; Webster, Robert G.

    2012-01-01

    Please cite this paper as: Hall et al. (2012) Avian influenza in shorebirds: experimental infection of ruddy turnstones (Arenaria interpres) with avian influenza virus. Influenza and Other Respiratory Viruses DOI: 10.1111/j.1750‐2659.2012.00358.x. Background  Low pathogenic avian influenza viruses (LPAIV) have been reported in shorebirds, especially at Delaware Bay, USA, during spring migration. However, data on patterns of virus excretion, minimal infectious doses, and clinical outcome are l...

  20. Maintained expression of the planar cell polarity molecule Vangl2 and reformation of hair cell orientation in the regenerating inner ear.

    Science.gov (United States)

    Warchol, Mark E; Montcouquiol, Mireille

    2010-09-01

    The avian inner ear possesses a remarkable ability to regenerate sensory hair cells after ototoxic injury. Regenerated hair cells possess phenotypes and innervation that are similar to those found in the undamaged ear, but little is known about the signaling pathways that guide hair cell differentiation during the regenerative process. The aim of the present study was to examine the factors that specify the orientation of hair cell stereocilia bundles during regeneration. Using organ cultures of the chick utricle, we show that hair cells are properly oriented after having regenerated entirely in vitro and that orientation is not affected by surgical removal of the striolar reversal zone. These results suggest that the orientation of regenerating stereocilia is not guided by the release of a diffusible morphogen from the striolar reversal zone but is specified locally within the regenerating sensory organ. In order to determine the nature of the reorientation cues, we examined the expression patterns of the core planar cell polarity molecule Vangl2 in the normal and regenerating utricle. We found that Vangl2 is asymmetrically expressed on cells within the sensory epithelium and that this expression pattern is maintained after ototoxic injury and throughout regeneration. Notably, treatment with a small molecule inhibitor of c-Jun-N-terminal kinase disrupted the orientation of regenerated hair cells. Both of these results are consistent with the hypothesis that noncanonical Wnt signaling guides hair cell orientation during regeneration.

  1. Emerging and reemerging diseases of avian wildlife.

    Science.gov (United States)

    Pello, Susan J; Olsen, Glenn H

    2013-05-01

    Of the many important avian wildlife diseases, aspergillosis, West Nile virus, avipoxvirus, Wellfleet Bay virus, avian influenza, and inclusion body disease of cranes are covered in this article. Wellfleet Bay virus, first identified in 2010, is considered an emerging disease. Avian influenza and West Nile virus have recently been in the public eye because of their zoonotic potential and links to wildlife. Several diseases labeled as reemerging are included because of recent outbreaks or, more importantly, recent research in areas such as genomics, which shed light on the mechanisms whereby these adaptable, persistent pathogens continue to spread and thrive. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Emerging and reemerging diseases of avian wildlife

    Science.gov (United States)

    Pello, Susan J.; Olsen, Glenn H.

    2013-01-01

    Of the many important avian wildlife diseases, aspergillosis, West Nile virus, avipoxvirus, Wellfleet Bay virus, avian influenza, and inclusion body disease of cranes are covered in this article. Wellfleet Bay virus, first identified in 2010, is considered an emerging disease. Avian influenza and West Nile virus have recently been in the public eye because of their zoonotic potential and links to wildlife. Several diseases labeled as reemerging are included because of recent outbreaks or, more importantly, recent research in areas such as genomics, which shed light on the mechanisms whereby these adaptable, persistent pathogens continue to spread and thrive.

  3. Adenosine A1 Receptor Protects Against Cisplatin Ototoxicity by Suppressing the NOX3/STAT1 Inflammatory Pathway in the Cochlea.

    Science.gov (United States)

    Kaur, Tejbeer; Borse, Vikrant; Sheth, Sandeep; Sheehan, Kelly; Ghosh, Sumana; Tupal, Srinivasan; Jajoo, Sarvesh; Mukherjea, Debashree; Rybak, Leonard P; Ramkumar, Vickram

    2016-04-06

    Cisplatin is a commonly used antineoplastic agent that produces ototoxicity that is mediated in part by increasing levels of reactive oxygen species (ROS) via the NOX3 NADPH oxidase pathway in the cochlea. Recent studies implicate ROS generation in mediating inflammatory and apoptotic processes and hearing loss by activating signal transducer and activator of transcription (STAT1). In this study, we show that the adenosine A1 receptor (A1AR) protects against cisplatin ototoxicity by suppressing an inflammatory response initiated by ROS generation via NOX3 NADPH oxidase, leading to inhibition of STAT1. Trans-tympanic administration of the A1AR agonist R-phenylisopropyladenosine (R-PIA) inhibited cisplatin-induced ototoxicity, as measured by auditory brainstem responses and scanning electron microscopy in male Wistar rats. This was associated with reduced NOX3 expression, STAT1 activation, tumor necrosis factor-α (TNF-α) levels, and apoptosis in the cochlea. In vitro studies in UB/OC-1 cells, an organ of Corti immortalized cell line, showed that R-PIA reduced cisplatin-induced phosphorylation of STAT1 Ser(727) (but not Tyr(701)) and STAT1 luciferase activity by suppressing the ERK1/2, p38, and JNK mitogen-activated protein kinase (MAPK) pathways.R-PIA also decreased the expression of STAT1 target genes, such as TNF-α, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) and reduced cisplatin-mediated apoptosis. These data suggest that the A1AR provides otoprotection by suppressing NOX3 and inflammation in the cochlea and could serve as an ideal target for otoprotective drug therapy. Cisplatin is a widely used chemotherapeutic agent for the treatment of solid tumors. Its use results in significant and permanent hearing loss, for which no US Food and Drug Administration-approved treatment is currently available. In this study, we targeted the cochlear adenosine A1 receptor (A1AR) by trans-tympanic injections of the agonist R

  4. Adenosine A1 Receptor Protects Against Cisplatin Ototoxicity by Suppressing the NOX3/STAT1 Inflammatory Pathway in the Cochlea

    Science.gov (United States)

    Kaur, Tejbeer; Borse, Vikrant; Sheth, Sandeep; Sheehan, Kelly; Ghosh, Sumana; Tupal, Srinivasan; Jajoo, Sarvesh; Mukherjea, Debashree; Rybak, Leonard P.

    2016-01-01

    Cisplatin is a commonly used antineoplastic agent that produces ototoxicity that is mediated in part by increasing levels of reactive oxygen species (ROS) via the NOX3 NADPH oxidase pathway in the cochlea. Recent studies implicate ROS generation in mediating inflammatory and apoptotic processes and hearing loss by activating signal transducer and activator of transcription (STAT1). In this study, we show that the adenosine A1 receptor (A1AR) protects against cisplatin ototoxicity by suppressing an inflammatory response initiated by ROS generation via NOX3 NADPH oxidase, leading to inhibition of STAT1. Trans-tympanic administration of the A1AR agonist R-phenylisopropyladenosine (R-PIA) inhibited cisplatin-induced ototoxicity, as measured by auditory brainstem responses and scanning electron microscopy in male Wistar rats. This was associated with reduced NOX3 expression, STAT1 activation, tumor necrosis factor-α (TNF-α) levels, and apoptosis in the cochlea. In vitro studies in UB/OC-1 cells, an organ of Corti immortalized cell line, showed that R-PIA reduced cisplatin-induced phosphorylation of STAT1 Ser727 (but not Tyr701) and STAT1 luciferase activity by suppressing the ERK1/2, p38, and JNK mitogen-activated protein kinase (MAPK) pathways. R-PIA also decreased the expression of STAT1 target genes, such as TNF-α, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) and reduced cisplatin-mediated apoptosis. These data suggest that the A1AR provides otoprotection by suppressing NOX3 and inflammation in the cochlea and could serve as an ideal target for otoprotective drug therapy. SIGNIFICANCE STATEMENT Cisplatin is a widely used chemotherapeutic agent for the treatment of solid tumors. Its use results in significant and permanent hearing loss, for which no US Food and Drug Administration-approved treatment is currently available. In this study, we targeted the cochlear adenosine A1 receptor (A1AR) by trans-tympanic injections of the agonist R

  5. Ongoing cell death and immune influences on regeneration in the vestibular sensory organs

    Science.gov (United States)

    Warchol, M. E.; Matsui, J. I.; Simkus, E. L.; Ogilive, J. M.

    2001-01-01

    Hair cells in the vestibular organs of birds have a relatively short life span. Mature hair cells appear to die spontaneously and are then quickly replaced by new hair cells that arise from the division of epithelial supporting cells. A similar regenerative mechanism also results in hair cell replacement after ototoxic damage. The cellular basis of hair cell turnover in the avian ear is not understood. We are investigating the signaling pathways that lead to hair cell death and the relationship between ongoing cell death and cell production. In addition, work from our lab and others has demonstrated that the avian inner ear contains a resident population of macrophages and that enhanced numbers of macrophages are recruited to sites of hair cells lesions. Those observations suggest that macrophages and their secretory products (cytokines) may be involved in hair cell regeneration. Consistent with that suggestion, we have found that treatment with the anti-inflammatory drug dexamethasone reduces regenerative cell proliferation in the avian ear, and that certain macrophage-secreted cytokines can influence the proliferation of vestibular supporting cells and the survival of statoacoustic neurons. Those results suggest a role for the immune system in the process of sensory regeneration in the inner ear.

  6. Imaging vibration of the cochlear partition of an excised guinea pig cochlea using phase-sensitive Fourier domain optical coherence tomography

    Science.gov (United States)

    Choudhury, Niloy; Zeng, Yaguang; Fridberger, Anders; Chen, Fangyi; Zha, Dingjun; Nuttall, Alfred L.; Wang, Ruikang K.

    2011-03-01

    Studying the sound stimulated vibrations of various membranes that form the complex structure of the organ of Corti in the cochlea of the inner ear is essential for understanding how the travelling sound wave of the basilar membrane couples its energy to the organ structures. In this paper we report the feasibility of using phase-sensitive Fourier domain optical coherence tomography (FD-OCT) to image the vibration of various micro-structures of the cochlea at the same time. An excised cochlea of a guinea pig was stimulated using sounds at various frequencies and vibration image was obtained. When measuring the apex area, vibration signal from different turns, which have different best response frequencies are obtained in the same image. The method has the potential to measure the response from a much wider region of the cochlea than any other currently used method. The noise floor for vibration image for the system at 200 Hz was ~0.3nm.

  7. The Use of Lexical Neighborhood Test (LNT) in the Assessment of Speech Recognition Performance of Cochlear Implantees with Normal and Malformed Cochlea.

    Science.gov (United States)

    Kant, Anjali R; Banik, Arun A

    2017-09-01

    The present study aims to use the model-based test Lexical Neighborhood Test (LNT), to assess speech recognition performance in early and late implanted hearing impaired children with normal and malformed cochlea. The LNT was administered to 46 children with congenital (prelingual) bilateral severe-profound sensorineural hearing loss, using Nucleus 24 cochlear implant. The children were grouped into Group 1-(early implantees with normal cochlea-EI); n = 15, 31/2-61/2 years of age; mean age at implantation-3½ years. Group 2-(late implantees with normal cochlea-LI); n = 15, 6-12 years of age; mean age at implantation-5 years. Group 3-(early implantees with malformed cochlea-EIMC); n = 9; 4.9-10.6 years of age; mean age at implantation-3.10 years. Group 4-(late implantees with malformed cochlea-LIMC); n = 7; 7-12.6 years of age; mean age at implantation-6.3 years. The following were the malformations: dysplastic cochlea, common cavity, Mondini's, incomplete partition-1 and 2 (IP-1 and 2), enlarged IAC. The children were instructed to repeat the words on hearing them. Means of the word and phoneme scores were computed. The LNT can also be used to assess speech recognition performance of hearing impaired children with malformed cochlea. When both easy and hard lists of LNT are considered, although, late implantees (with or without normal cochlea), have achieved higher word scores than early implantees, the differences are not statistically significant. Using LNT for assessing speech recognition enables a quantitative as well as descriptive report of phonological processes used by the children.

  8. Avian Influenza Policy Analysis | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... to the loss of tens of millions of birds, either to disease or preventive culling. ... is to stimulate regional collaboration on avian influenza prevention and control. ... IWRA/IDRC webinar on climate change and adaptive water management.

  9. Avian models in teratology and developmental toxicology.

    Science.gov (United States)

    Smith, Susan M; Flentke, George R; Garic, Ana

    2012-01-01

    The avian embryo is a long-standing model for developmental biology research. It also has proven utility for toxicology research both in ovo and in explant culture. Like mammals, avian embryos have an allantois and their developmental pathways are highly conserved with those of mammals, thus avian models have biomedical relevance. Fertile eggs are inexpensive and the embryo develops rapidly, allowing for high-throughput. The chick genome is sequenced and significant molecular resources are available for study, including the ability for genetic manipulation. The absence of a placenta permits the direct study of an agent's embryotoxic effects. Here, we present protocols for using avian embryos in toxicology research, including egg husbandry and hatch, toxicant delivery, and assessment of proliferation, apoptosis, and cardiac structure and function.

  10. Avian Habitat Data; Seward Peninsula, Alaska, 2012

    Data.gov (United States)

    Department of the Interior — This data product contains avian habitat data collected on the Seward Peninsula, Alaska, USA, during 21 May – 10 June 2012. We conducted replicated 10-min surveys...

  11. Isolation of avian influenza virus in Texas.

    Science.gov (United States)

    Glass, S E; Naqi, S A; Grumbles, L C

    1981-01-01

    An avian influenza virus with surface antigens similar to those of fowl plague virus (Hav 1 Nav 2) was isolated in 1979 from 2 commercial turkey flocks in Central Texas. Two flocks in contact with these infected flocks developed clinical signs, gross lesions, and seroconversion but yielded no virus. This was the first recorded incidence of clinical avian influenza in Texas turkeys and only the second time that an agent with these surface antigens was isolated from turkeys in U.S.

  12. Relationship of glucocorticoid receptor expression in peripheral blood mononuclear cells and the cochlea of guinea pigs and effects of dexamethasone administration.

    Directory of Open Access Journals (Sweden)

    Ling Lu

    Full Text Available BACKGROUND: Glucocorticoids (GCs are widely used to treat sudden sensorineural hearing loss (SSNHL and significantly improve hearing. However, GC insensitivity has been observed in some patients of SSNHL. OBJECTIVE: To study the correlation between GR expression in peripheral blood mononuclear cells (PBMCs and in the cochlea of guinea pigs at mRNA and protein levels. METHODS: One group of guinea pigs received dexamethasone (10 mg/kg/day intraperitoneally for 7 consecutive days (dexamethasone group, and another group of guinea pigs received normal saline (control group. Real time PCR and Western blotting were used to detect the expression of GR mRNA and GR protein in PBMCs and the cochleae. RESULTS: The GR mRNA and GR protein were detected in both PBMCs and the cochlear tissue of guinea pigs. GR mRNA and GR protein levels in PBMCs were positively correlated with those in the cochlea. The expression of GR mRNA and GR protein was significantly increased in the dexamethasone group compared to the control group. CONCLUSIONS: Levels of GR mRNA and GR protein in the PBMCs were positively correlated with those in the cochlea of guinea pigs. Systemic dexamethasone treatment can significantly up-regulate GR expression in PBMCs and in the cochlea. Measurement of the GR level in PBMCs could be used as an indicator of GR level in the cochlea.

  13. Synthetic Phage for Tissue Regeneration

    Directory of Open Access Journals (Sweden)

    So Young Yoo

    2014-01-01

    Full Text Available Controlling structural organization and signaling motif display is of great importance to design the functional tissue regenerating materials. Synthetic phage, genetically engineered M13 bacteriophage has been recently introduced as novel tissue regeneration materials to display a high density of cell-signaling peptides on their major coat proteins for tissue regeneration purposes. Structural advantages of their long-rod shape and monodispersity can be taken together to construct nanofibrous scaffolds which support cell proliferation and differentiation as well as direct orientation of their growth in two or three dimensions. This review demonstrated how functional synthetic phage is designed and subsequently utilized for tissue regeneration that offers potential cell therapy.

  14. Understanding Urban Regeneration in Turkey

    Science.gov (United States)

    Candas, E.; Flacke, J.; Yomralioglu, T.

    2016-06-01

    In Turkey, rapid population growth, informal settlements, and buildings and infrastructures vulnerable to natural hazards are seen as the most important problems of cities. Particularly disaster risk cannot be disregarded, as large parts of various cities are facing risks from earthquakes, floods and landslides and have experienced loss of lives in the recent past. Urban regeneration is an important planning tool implemented by local and central governments in order to reduce to disaster risk and to design livable environments for the citizens. The Law on the Regeneration of Areas under Disaster Risk, commonly known as the Urban Regeneration Law, was enacted in 2012 (Law No.6306, May 2012). The regulation on Implementation of Law No. 6306 explains the fundamental steps of the urban regeneration process. The relevant institutions furnished with various authorities such as expropriation, confiscation and changing the type and place of your property which makes urban regeneration projects very important in terms of property rights. Therefore, urban regeneration projects have to be transparent, comprehensible and acceptable for all actors in the projects. In order to understand the urban regeneration process, the legislation and projects of different municipalities in Istanbul have been analyzed. While some steps of it are spatial data demanding, others relate to land values. In this paper an overview of the urban regeneration history and activities in Turkey is given. Fundamental steps of the urban regeneration process are defined, and particularly spatial-data demanding steps are identified.

  15. Radiosurgery for Para-IAC Meningiomas: The Effect of Radiation Dose to the Cochlea on Hearing Outcome

    International Nuclear Information System (INIS)

    Kim, Young-Hoon; Kim, Dong Gyu; Han, Jung Ho; Chung, Hyun-Tai; Kim, In Kyung; Song, Sang Woo; Park, Jeong-Hoon; Kim, Jin Wook; Kim, Yong Hwy; Park, Chul-Kee; Kim, Chae-Yong; Paek, Sun Ha; Jung, Hee-Won

    2012-01-01

    Purpose: This study was performed to assess the radiosurgical results of meningiomas extending into the internal acoustic canal (para-IAC meningiomas), with a particular focus on the effect of radiation dose to the cochlea on hearing outcome. Methods and Materials: A total of 50 patients who underwent radiosurgery for para-IAC meningiomas between 1998 and 2009, which were followed for 2 years, were enrolled. The mean age was 55.8 years (range, 15–75). The mean tumor volume was 6.1 cm 3 (range, 1.0–19.0), the mean tumor length in the IAC was 6.9 mm (range, 1.3–13.3), and the mean prescribed marginal dose was 13.1 Gy (range, 10–15) at an isodose line of 50%. The mean follow-up duration was 46 months (range, 24–122). Results: Eight (16.0%) patients had nonserviceable hearing at the time of surgery. At the last follow-up, the tumor control rate was 94%; unchanged in 17 patients, decreased in 30 patients, and increased in 3 patients. Among 42 patients with serviceable hearing at the time of radiosurgery, it was preserved in 41 (97.6%) patients at the last follow-up. The maximal and mean radiation doses to the cochleae of these 41 patients were 5.8 Gy ± 0.3 (range, 3.1–11.5) and 4.3 Gy ± 0.2 (range, 2.2–7.5), respectively. The maximal dose to the cochlea of the patient who lost hearing after radiosurgery was 4.7 Gy. Conclusions: The radiation dose to the cochlea may have the minimal toxic effect on the hearing outcome in patients who undergo radiosurgery for para-IAC meningiomas.

  16. Ecology and conservation biology of avian malaria

    Science.gov (United States)

    LaPointe, Dennis A.; Atkinson, Carter T.; Samuel, Michael D.

    2012-01-01

    Avian malaria is a worldwide mosquito-borne disease caused by Plasmodium parasites. These parasites occur in many avian species but primarily affect passerine birds that have not evolved with the parasite. Host pathogenicity, fitness, and population impacts are poorly understood. In contrast to continental species, introduced avian malaria poses a substantial threat to naive birds on Hawaii, the Galapagos, and other archipelagoes. In Hawaii, transmission is maintained by susceptible native birds, competence and abundance of mosquitoes, and a disease reservoir of chronically infected native birds. Although vector habitat and avian communities determine the geographic distribution of disease, climate drives transmission patterns ranging from continuous high infection in warm lowland forests, seasonal infection in midelevation forests, and disease-free refugia in cool high-elevation forests. Global warming is expected to increase the occurrence, distribution, and intensity of avian malaria across this elevational gradient and threaten high-elevation refugia, which is the key to survival of many susceptible Hawaiian birds. Increased temperatures may have already increased global avian malaria prevalence and contributed to an emergence of disease in New Zealand.

  17. Cell-cell junctions: a target of acoustic overstimulation in the sensory epithelium of the cochlea

    Directory of Open Access Journals (Sweden)

    Zheng Guiliang

    2012-06-01

    Full Text Available Abstract Background Exposure to intense noise causes the excessive movement of the organ of Corti, stretching the organ and compromising sensory cell functions. We recently revealed changes in the transcriptional expression of multiple adhesion-related genes during the acute phases of cochlear damage, suggesting that the disruption of cell-cell junctions is an early event in the process of cochlear pathogenesis. However, the functional state of cell junctions in the sensory epithelium is not clear. Here, we employed graded dextran-FITC, a macromolecule tracer that is impermeable to the organ of Corti under physiological conditions, to evaluate the barrier function of cell junctions in normal and noise-traumatized cochlear sensory epithelia. Results Exposure to an impulse noise of 155 dB (peak sound pressure level caused a site-specific disruption in the intercellular junctions within the sensory epithelium of the chinchilla cochlea. The most vulnerable sites were the junctions among the Hensen cells and between the Hensen and Deiters cells within the outer zone of the sensory epithelium. The junction clefts that formed in the reticular lamina were permeable to 40 and 500 but not 2,000 kDa dextran-FITC macromolecules. Moreover, this study showed that the interruption of junction integrity occurred in the reticular lamina and also in the basilar membrane, a site that had been considered to be resistant to acoustic injury. Finally, our study revealed a general spatial correlation between the site of sensory cell damage and the site of junction disruption. However, the two events lacked a strict one-to-one correlation, suggesting that the disruption of cell-cell junctions is a contributing, but not the sole, factor for initiating acute sensory cell death. Conclusions Impulse noise causes the functional disruption of intercellular junctions in the sensory epithelium of the chinchilla cochlea. This disruption occurs at an early phase of cochlear

  18. Microbiological soil regeneration

    International Nuclear Information System (INIS)

    Behrens, D.; Wiesner, J.

    1992-01-01

    The Interdiciplinary Task Force ''Environmental Biotechnology - Soil'' of DECHEMA aims to pool the knowledge potential of the Dechema study committees on environmental biotechnology and soil protection with a view to the advancement of microbiological soil decontamination techniques. This conference volume on the 9th expert meeting of Dechema on environmental protection subjects entitled ''Microbiological Soil Regeneration'', held on February 27th and 28th, 1991, and the subsequent compilation of results give an intermediate account of the ongoing work of the Dechema Task Force. (orig.) [de

  19. Usefulness of Intravital Multiphoton Microscopy in Visualizing Study of Mouse Cochlea and Volume Changes in the Scala Media.

    Science.gov (United States)

    Ju, Hyun Mi; Lee, Sun Hee; Kong, Tae Hoon; Kwon, Seung-Hae; Choi, Jin Sil; Seo, Young Joon

    2017-01-01

    Conventional microscopy has limitations in viewing the cochlear microstructures due to three-dimensional spiral structure and the overlying bone. But these issues can be overcome by imaging the cochlea in vitro with intravital multiphoton microscopy (MPM). By using near-infrared lasers for multiphoton excitation, intravital MPM can detect endogenous fluorescence and second harmonic generation of tissues. In this study, we used intravital MPM to visualize various cochlear microstructures without any staining and non-invasively analyze the volume changes of the scala media (SM) without removing the overlying cochlear bone. The intravital MPM images revealed various tissue types, ranging from thin membranes to dense bone, as well as the spiral ganglion beneath the cochlear bone. The two-dimensional, cross-sectional, and serial z-stack intravital MPM images also revealed the spatial dilation of the SM in the temporal bone of pendrin-deficient mice. These findings suggest that intravital MPM might serve as a new method for obtaining microanatomical information regarding the cochlea, similar to standard histopathological analyses in the animal study for the cochlea. Given the capability of intravital MPM for detecting an increase in the volume of the SM in pendrin-deficient mice, it might be a promising new tool for assessing the pathophysiology of hearing loss in the future.

  20. Survival of partially differentiated mouse embryonic stem cells in the scala media of the guinea pig cochlea.

    Science.gov (United States)

    Hildebrand, Michael S; Dahl, Hans-Henrik M; Hardman, Jennifer; Coleman, Bryony; Shepherd, Robert K; de Silva, Michelle G

    2005-12-01

    The low regenerative capacity of the hair cells of the mammalian inner ear is a major obstacle for functional recovery following sensorineural hearing loss. A potential treatment is to replace damaged tissue by transplantation of stem cells. To test this approach, undifferentiated and partially differentiated mouse embryonic stem (ES) cells were delivered into the scala media of the deafened guinea pig cochlea. Transplanted cells survived in the scala media for a postoperative period of at least nine weeks, evidenced by histochemical and direct fluorescent detection of enhanced green fluorescent protein (EGFP). Transplanted cells were discovered near the spiral ligament and stria vascularis in the endolymph fluid of the scala media. In some cases, cells were observed close to the damaged organ of Corti structure. There was no evidence of significant immunological rejection of the implanted ES cells despite the absence of immunosuppression. Our surgical approach allowed efficient delivery of ES cells to the scala media while preserving the delicate structures of the cochlea. This is the first report of the survival of partially differentiated ES cells in the scala media of the mammalian cochlea, and it provides support for the potential of cell-based therapies for sensorineural hearing impairment.

  1. Usefulness of Intravital Multiphoton Microscopy in Visualizing Study of Mouse Cochlea and Volume Changes in the Scala Media

    Directory of Open Access Journals (Sweden)

    Hyun Mi Ju

    2017-07-01

    Full Text Available Conventional microscopy has limitations in viewing the cochlear microstructures due to three-dimensional spiral structure and the overlying bone. But these issues can be overcome by imaging the cochlea in vitro with intravital multiphoton microscopy (MPM. By using near-infrared lasers for multiphoton excitation, intravital MPM can detect endogenous fluorescence and second harmonic generation of tissues. In this study, we used intravital MPM to visualize various cochlear microstructures without any staining and non-invasively analyze the volume changes of the scala media (SM without removing the overlying cochlear bone. The intravital MPM images revealed various tissue types, ranging from thin membranes to dense bone, as well as the spiral ganglion beneath the cochlear bone. The two-dimensional, cross-sectional, and serial z-stack intravital MPM images also revealed the spatial dilation of the SM in the temporal bone of pendrin-deficient mice. These findings suggest that intravital MPM might serve as a new method for obtaining microanatomical information regarding the cochlea, similar to standard histopathological analyses in the animal study for the cochlea. Given the capability of intravital MPM for detecting an increase in the volume of the SM in pendrin-deficient mice, it might be a promising new tool for assessing the pathophysiology of hearing loss in the future.

  2. Regeneration of desiccants with solar energy

    Energy Technology Data Exchange (ETDEWEB)

    Ghate, S.R.; Butts, C.L.; Lown, J.B.

    1985-01-01

    Saturated silica gel was regenerated with solar energy. This paper describes the experimental set-up for silica gel regeneration and data collection. The regenerated silica gel can be used to dry high moisture in-shell pecans.

  3. Inflammatory and immune responses in the cochlea: potential therapeutic targets for sensorineural hearing loss

    Directory of Open Access Journals (Sweden)

    Masato eFujioka

    2014-12-01

    Full Text Available The inner ear was previously assumed to be an immune-privileged organ due to the existence of its tight junction-based blood-labyrinth barrier. However, studies performed during the past decade revealed that the mesenchymal region of the cochlea, including its lateral wall, is a common site of inflammation. Neutrophils do not enter this region, which is consistent with the old dogma; however, bone marrow-derived resident macrophages are always present in the spiral ligament of the lateral wall and are activated in response to various types of insults, including noise exposure, ischemia, mitochondrial damage and surgical stress. Recent studies have also revealed another type of immune cell, called perivascular melanocyte-like macrophages (PVM/Ms, in the stria vascularis. These dedicated antigen-presenting cells also control vascular contraction and permeability. This review discusses a series of reports regarding inflammatory/immune cells in the cochlear lateral wall, the pathways involved in cochlear damage and their potential as therapeutic targets.

  4. Structural Dynamic Response Compressing Technique in Bridges using a Cochlea-inspired Artificial Filter Bank (CAFB)

    International Nuclear Information System (INIS)

    Heo, G; Jeon, J; Son, B; Kim, C; Jeon, S; Lee, C

    2016-01-01

    In this study, a cochlea-inspired artificial filter bank (CAFB) was developed to efficiently obtain dynamic response of a structure, and a dynamic response measurement of a cable-stayed bridge model was also carried out to evaluate the performance of the developed CAFB. The developed CAFB used a band-pass filter optimizing algorithm (BOA) and peakpicking algorithm (PPA) to select and compress dynamic response signal containing the modal information which was significant enough. The CAFB was then optimized about the El-Centro earthquake wave which was often used in the construction research, and the software implementation of CAFB was finally embedded in the unified structural management system (USMS). For the evaluation of the developed CAFB, a real time dynamic response experiment was performed on a cable-stayed bridge model, and the response of the cable-stayed bridge model was measured using both the traditional wired system and the developed CAFB-based USMS. The experiment results showed that the compressed dynamic response acquired by the CAFB-based USMS matched significantly with that of the traditional wired system while still carrying sufficient modal information of the cable-stayed bridge. (paper)

  5. Accumulation of potassium in scala vestibuli perilymph of the mammalian cochlea.

    Science.gov (United States)

    Salt, A N; Ohyama, K

    1993-01-01

    Movements of potassium (K+) were monitored during perfusion of either the scala tympani (ST) or the scala vestibuli (SV) of the guinea pig cochlea with a solution containing 15 mmol/LK+. A highly asymmetric clearance of K+ was observed, with K+ rapidly being taken up from the ST and allowed to accumulate in the SV. Under some conditions the SV K+ concentration could exceed that in the perfused ST. These observations are believed to result from the distortion of passive K+ diffusion by the high circulating current of K+ that is part of the transduction process. Calculations are presented to demonstrate that circulating fluxes are of sufficient magnitude to generate the results observed. The high rate of circulating K+ current is probably also responsible for the difference in physiologic K+ concentration between the ST and SV, in which the ST perilymph K+ concentration is typically found to be half that of the SV. A clearance of K+ from the ST and its eventual accumulation in the SV could play a role in how the ear responds to abnormal ion concentrations, such as may occur in Meniere's disease. It is proposed that an accumulation of K+ in the SV would result in vestibular dysfunction that might contribute to the vestibular symptoms of the disease.

  6. Differential physiologic effects of perfusion of scala tympani versus scala vestibuli in the ischemic cochlea.

    Science.gov (United States)

    Kobayashi, T; Rokugo, M; Takasaka, T; Thalmann, R

    1993-07-01

    The effectiveness of perilymphatic perfusion with oxygenated artificial media upon the endocochlear potential (EP) was measured during systemic ischemia in the guinea pig. Differences in the effects of perfusion of the two perilymphatic scalae were determined. Perfusion of scala vestibuli with oxygenated artificial perilymph at a high flow rate resulted in complete recovery of the EP to the pre-ischemic level, whereas perfusion of scala tympani with the same medium was unable to effect complete recovery. The recovery obtained by perfusion of scala tympani was about half that obtained of scala vestibuli. The pO2 in scala media was measured during perfusion by means of oxygen-sensitive microelectrodes. perfusion of scala vestibuli led to an approximately two-fold higher pO2 in scala media than perfusion of scala tympani. During perfusion, the pO2 in scala media varied dependent upon depth of electrode insertion, with a gradient decreasing toward the stria vascularis, a direction opposite to that seen under normal metabolic conditions. These findings suggest that, in the ischemic cochlea, oxygen enters scala media more easily from scala vestibuli across Reissner's membrane than from scala tympani via the basilar membrane/organ of Corti complex.

  7. Optical stimulation of the hearing and deaf cochlea under thermal and stress confinement condition

    Science.gov (United States)

    Schultz, M.; Baumhoff, P.; Kallweit, N.; Sato, M.; Krüger, A.; Ripken, T.; Lenarz, T.; Kral, A.

    2014-03-01

    There is a controversy, to which extend cochlear stimulation with near infrared laser pulses at a wavelength of 1860 nm is based on optoacoustic stimulation of intact hair cells or -in contrast- is based on direct stimulation of the nerve cells in absence of functional hair cells. Thermal and stress confinement conditions apply, because of the pulse duration range (5 ns, 10 μs-20 ms) of the two lasers used. The dependency of the signal characteristics on pulse peak power and pulse duration was investigated in this study. The compound action potential (CAP) was measured during stimulation of the cochlea of four anaesthetized guinea pigs, which were hearing at first and afterwards acutely deafened using intracochlear neomycin-rinsing. For comparison hydrophone measurements in a water tank were performed to investigate the optoacoustic signals at different laser interaction regimes. With rising pulse peak power CAPs of the hearing animals showed first a threshold, then a positively correlated and finally a saturating dependency. CAPs also showed distinct responses at laser onset and offset separated with the pulse duration. At pulse durations shorter than physiological response times the signals merged. Basically the same signal characteristics were observed in the optoacoustic hydrophone measurements, scaled with the sensitivity and response time of the hydrophone. Taking together the qualitative correspondence in the signal response and the absence of any CAPs in deafened animals our results speak in favor of an optoacoustic stimulation of intact hair cells rather than a direct stimulation of nerve cells.

  8. Energy Flux in the Cochlea: Evidence Against Power Amplification of the Traveling Wave.

    Science.gov (United States)

    van der Heijden, Marcel; Versteegh, Corstiaen P C

    2015-10-01

    Traveling waves in the inner ear exhibit an amplitude peak that shifts with frequency. The peaking is commonly believed to rely on motile processes that amplify the wave by inserting energy. We recorded the vibrations at adjacent positions on the basilar membrane in sensitive gerbil cochleae and tested the putative power amplification in two ways. First, we determined the energy flux of the traveling wave at its peak and compared it to the acoustic power entering the ear, thereby obtaining the net cochlear power gain. For soft sounds, the energy flux at the peak was 1 ± 0.6 dB less than the middle ear input power. For more intense sounds, increasingly smaller fractions of the acoustic power actually reached the peak region. Thus, we found no net power amplification of soft sounds and a strong net attenuation of intense sounds. Second, we analyzed local wave propagation on the basilar membrane. We found that the waves slowed down abruptly when approaching their peak, causing an energy densification that quantitatively matched the amplitude peaking, similar to the growth of sea waves approaching the beach. Thus, we found no local power amplification of soft sounds and strong local attenuation of intense sounds. The most parsimonious interpretation of these findings is that cochlear sensitivity is not realized by amplifying acoustic energy, but by spatially focusing it, and that dynamic compression is realized by adjusting the amount of dissipation to sound intensity.

  9. Macrophage-Mediated Glial Cell Elimination in the Postnatal Mouse Cochlea

    Directory of Open Access Journals (Sweden)

    LaShardai N. Brown

    2017-12-01

    Full Text Available Hearing relies on the transmission of auditory information from sensory hair cells (HCs to the brain through the auditory nerve. This relay of information requires HCs to be innervated by spiral ganglion neurons (SGNs in an exclusive manner and SGNs to be ensheathed by myelinating and non-myelinating glial cells. In the developing auditory nerve, mistargeted SGN axons are retracted or pruned and excessive cells are cleared in a process referred to as nerve refinement. Whether auditory glial cells are eliminated during auditory nerve refinement is unknown. Using early postnatal mice of either sex, we show that glial cell numbers decrease after the first postnatal week, corresponding temporally with nerve refinement in the developing auditory nerve. Additionally, expression of immune-related genes was upregulated and macrophage numbers increase in a manner coinciding with the reduction of glial cell numbers. Transient depletion of macrophages during early auditory nerve development, using transgenic CD11bDTR/EGFP mice, resulted in the appearance of excessive glial cells. Macrophage depletion caused abnormalities in myelin formation and transient edema of the stria vascularis. Macrophage-depleted mice also showed auditory function impairment that partially recovered in adulthood. These findings demonstrate that macrophages contribute to the regulation of glial cell number during postnatal development of the cochlea and that glial cells play a critical role in hearing onset and auditory nerve maturation.

  10. Manipulations to regenerate aspen ecosystems

    Science.gov (United States)

    Wayne D. Shepperd

    2001-01-01

    Vegetative regeneration of aspen can be initiated through manipulations that provide hormonal stimulation, proper growth environment, and sucker protection - the three elements of the aspen regeneration triangle. The correct course of action depends upon a careful evaluation of the size, vigor, age, and successional status of the existing clone. Soils and site...

  11. Acoustic field modulation in regenerators

    Science.gov (United States)

    Hu, J. Y.; Wang, W.; Luo, E. C.; Chen, Y. Y.

    2016-12-01

    The regenerator is a key component that transfers energy between heat and work. The conversion efficiency is significantly influenced by the acoustic field in the regenerator. Much effort has been spent to quantitatively determine this influence, but few comprehensive experimental verifications have been performed because of difficulties in modulating and measuring the acoustic field. In this paper, a method requiring two compressors is introduced and theoretically investigated that achieves acoustic field modulation in the regenerator. One compressor outputs the acoustic power for the regenerator; the other acts as a phase shifter. A RC load dissipates the acoustic power out of both the regenerator and the latter compressor. The acoustic field can be modulated by adjusting the current in the two compressors and opening the RC load. The acoustic field is measured with pressure sensors instead of flow-field imaging equipment, thereby greatly simplifying the experiment.

  12. Habitat use and implications for avian species in Sambisa game ...

    African Journals Online (AJOL)

    Habitat use and implications for avian species in Sambisa game reserve, Borno state, Nigeria. ... avian species diversity and abundance in Sambisa Game Reserve in Borno State, Sudano-Sahelian vegetation. ... AJOL African Journals Online.

  13. Proceedings of National Avian-Wind Power Planning Meeting IV

    Energy Technology Data Exchange (ETDEWEB)

    NWCC Avian Subcommittee

    2001-05-01

    OAK-B135 The purpose of the fourth meeting was to (1) share research and update research conducted on avian wind interactions (2) identify questions and issues related to the research results, (3) develop conclusions about some avian/wind power issues, and (4) identify questions and issues for future avian research.

  14. Avian metapneumovirus subgroup C infection in chickens, China.

    Science.gov (United States)

    Wei, Li; Zhu, Shanshan; Yan, Xv; Wang, Jing; Zhang, Chunyan; Liu, Shuhang; She, Ruiping; Hu, Fengjiao; Quan, Rong; Liu, Jue

    2013-07-01

    Avian metapneumovirus causes acute respiratory tract infection and reductions in egg production in various avian species. We isolated and characterized an increasingly prevalent avian metapneumovirus subgroup C strain from meat-type commercial chickens with severe respiratory signs in China. Culling of infected flocks could lead to economic consequences.

  15. Avian Metapneumovirus Subgroup C Infection in Chickens, China

    OpenAIRE

    Wei, Li; Zhu, Shanshan; Yan, Xv; Wang, Jing; Zhang, Chunyan; Liu, Shuhang; She, Ruiping; Hu, Fengjiao; Quan, Rong; Liu, Jue

    2013-01-01

    Avian metapneumovirus causes acute respiratory tract infection and reductions in egg production in various avian species. We isolated and characterized an increasingly prevalent avian metapneumovirus subgroup C strain from meat-type commercial chickens with severe respiratory signs in China. Culling of infected flocks could lead to economic consequences.

  16. Results from neutral kaon regeneration at high energies

    International Nuclear Information System (INIS)

    Hladky, J.

    1976-01-01

    Experimental neutral kaon regeneration results at Serpukhov energies up to 50 GeV are presented, including the coherent regeneration on hydrogen, deuterium and carbon regenerators and elastic regeneration on deuterium and carbon regenerators. (author)

  17. Deforestation and avian infectious diseases.

    Science.gov (United States)

    Sehgal, R N M

    2010-03-15

    In this time of unprecedented global change, infectious diseases will impact humans and wildlife in novel and unknown ways. Climate change, the introduction of invasive species, urbanization, agricultural practices and the loss of biodiversity have all been implicated in increasing the spread of infectious pathogens. In many regards, deforestation supersedes these other global events in terms of its immediate potential global effects in both tropical and temperate regions. The effects of deforestation on the spread of pathogens in birds are largely unknown. Birds harbor many of the same types of pathogens as humans and in addition can spread infectious agents to humans and other wildlife. It is thought that avifauna have gone extinct due to infectious diseases and many are presently threatened, especially endemic island birds. It is clear that habitat degradation can pose a direct threat to many bird species but it is uncertain how these alterations will affect disease transmission and susceptibility to disease. The migration and dispersal of birds can also change with habitat degradation, and thus expose populations to novel pathogens. Some recent work has shown that the results of landscape transformation can have confounding effects on avian malaria, other haemosporidian parasites and viruses. Now with advances in many technologies, including mathematical and computer modeling, genomics and satellite tracking, scientists have tools to further research the disease ecology of deforestation. This research will be imperative to help predict and prevent outbreaks that could affect avifauna, humans and other wildlife worldwide.

  18. Muscle regeneration in mitochondrial myopathies

    DEFF Research Database (Denmark)

    Krag, T O; Hauerslev, S; Jeppesen, T D

    2013-01-01

    Mitochondrial myopathies cover a diverse group of disorders in which ragged red and COX-negative fibers are common findings on muscle morphology. In contrast, muscle degeneration and regeneration, typically found in muscular dystrophies, are not considered characteristic features of mitochondrial...... myopathies. We investigated regeneration in muscle biopsies from 61 genetically well-defined patients affected by mitochondrial myopathy. Our results show that the perturbed energy metabolism in mitochondrial myopathies causes ongoing muscle regeneration in a majority of patients, and some were even affected...

  19. Enhanced bioavailability of nerve growth factor with phytantriol lipid-based crystalline nanoparticles in cochlea

    Directory of Open Access Journals (Sweden)

    Bu M

    2015-11-01

    Full Text Available Meng Bu,1,2 Jingling Tang,3 Yinghui Wei,4 Yanhui Sun,1 Xinyu Wang,1 Linhua Wu,2 Hongzhuo Liu1 1School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, People’s Republic of China; 2Department of Pharmacy, the Second Affiliated Hospital, 3School of Pharmacy, Harbin Medical University, Harbin, People’s Republic of China; 4College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, People’s Republic of China Purpose: Supplementation of exogenous nerve growth factor (NGF into the cochlea of deafened animals rescues spiral ganglion cells from degeneration. However, a safe and potent delivery of therapeutic proteins, such as NGF, to spiral ganglion cells remains one of the greatest challenges. This study presents the development of self-assembled cubic lipid-based crystalline nanoparticles to enhance inner ear bioavailability of bioactive NGF via a round window membrane route.Methods: A novel nanocarrier-entrapped NGF was developed based on phytantriol by a liquid precursor dilution, with Pluronic® F127 and propylene glycol as the surfactant and solubilizer, respectively. Upon dilution of the liquid lipid precursors, monodispersed submicron-sized particles with a slight negative charge formed spontaneously.Results: Biological activity of entrapped NGF was assessed using pheochromocytoma cells with NGF-loaded reservoirs to induce significant neuronal outgrowth, similar to that seen in free NGF-treated controls. Finally, a 3.28-fold increase in inner ear bioavailability was observed after administration of phytantriol lipid-based crystalline nanoparticles as compared to free drug, contributing to an enhanced drug permeability of the round window membrane. Conclusion: Data presented here demonstrate the potential of lipid-based crystalline nanoparticles to improve the outcomes of patients bearing cochlear implants. Keywords: nerve growth factor, lipid-based crystalline nanoparticles, PC12 cells, inner ear drug

  20. Gender differences in myogenic regulation along the vascular tree of the gerbil cochlea.

    Directory of Open Access Journals (Sweden)

    Katrin Reimann

    Full Text Available Regulation of cochlear blood flow is critical for hearing due to its exquisite sensitivity to ischemia and oxidative stress. Many forms of hearing loss such as sensorineural hearing loss and presbyacusis may involve or be aggravated by blood flow disorders. Animal experiments and clinical outcomes further suggest that there is a gender preference in hearing loss, with males being more susceptible. Autoregulation of cochlear blood flow has been demonstrated in some animal models in vivo, suggesting that similar to the brain, blood vessels supplying the cochlea have the ability to control flow within normal limits, despite variations in systemic blood pressure. Here, we investigated myogenic regulation in the cochlear blood supply of the Mongolian gerbil, a widely used animal model in hearing research. The cochlear blood supply originates at the basilar artery, followed by the anterior inferior cerebellar artery, and inside the inner ear, by the spiral modiolar artery and the radiating arterioles that supply the capillary beds of the spiral ligament and stria vascularis. Arteries from male and female gerbils were isolated and pressurized using a concentric pipette system. Diameter changes in response to increasing luminal pressures were recorded by laser scanning microscopy. Our results show that cochlear vessels from male and female gerbils exhibit myogenic regulation but with important differences. Whereas in male gerbils, both spiral modiolar arteries and radiating arterioles exhibited pressure-dependent tone, in females, only radiating arterioles had this property. Male spiral modiolar arteries responded more to L-NNA than female spiral modiolar arteries, suggesting that NO-dependent mechanisms play a bigger role in the myogenic regulation of male than female gerbil cochlear vessels.

  1. 17β-Estradiol reduces nitric oxide production in the Guinea pig cochlea.

    Science.gov (United States)

    Heinrich, U-R; Brieger, J; Striedter, C; Fischer, I; Schmidtmann, I; Li, H; Mann, W J; Helling, K

    2013-11-01

    Intense noise exposure and the application of ototoxic substances result in increased levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS), such as nitric oxide (NO). In order to reduce the free NO concentration in the inner ear under pathological conditions, the use of natural cytoprotective substances such as 17β-estradiol is a promising therapeutic concept. In male guinea pigs the organ of Corti and the lateral wall were isolated from the cochlea and afterwards incubated for 6 h in cell-culture medium. 17β-Estradiol was adjusted in 2 concentrations to organ cultures of the right ears (12 animals per concentration). The left ears were used as controls. The NO production was quantified in the supernatant by chemiluminescence after incubation. Depending on the concentration, 17β-estradiol reduced NO in the organ of Corti by 43% (p=0.015) and 46% (p=0.026), respectively. In the lateral wall, the NO concentration was reduced by 24%, but without statistical significance (p=0.86). However, when analyzing the association between the 2 cochlear regions for each animal separately, the NO concentrations were lower in nearly all 17β-estradiol-treated ears compared to controls. In order to demonstrate the flexibility of the organ culture system, the NO donor DETA NONOate and the nitric oxide synthase inhibitors L-NAME and L-NMMA were applied. The electron microscopic analysis revealed a well-preserved cochlear cell morphology after incubation. The ability of 17β-estradiol to influence the NO production preferentially in the organ of Corti might offer new therapeutic perspectives for inner ear protection. © Georg Thieme Verlag KG Stuttgart · New York.

  2. Hyposmotic stimulation-induced nitric oxide production in outer hair cells of the guinea pig cochlea.

    Science.gov (United States)

    Takeda-Nakazawa, Hiroko; Harada, Narinobu; Shen, Jing; Kubo, Nobuo; Zenner, Hans-Peter; Yamashita, Toshio

    2007-08-01

    Nitric oxide (NO) production during hyposmotic stimulation in outer hair cells (OHCs) of the guinea pig cochlea was investigated using the NO sensitive dye DAF-2. Simultaneous measurement of the cell length and NO production showed rapid hyposmotic-induced cell swelling to precede NO production in OHCs. Hyposmotic stimulation failed to induce NO production in the Ca2+-free solution. L-NG-nitroarginine methyl ester (L-NAME), a non-specific NO synthase inhibitor and gadolinium, a stretch-activated channel blocker inhibited the hyposmotic stimulation-induced NO production whereas suramin, a P2 receptor antagonist did not. S-nitroso-N-acetylpenicillamine (SNAP), a NO donor inhibited the hyposmotic stimulation-induced increase in the intracellular Ca2+ concentrations ([Ca2+]i) while L-NAME enhanced it. 1H-[1,2,4]oxadiazole[4,3a]quinoxalin-1-one, an inhibitor of guanylate cyclase and KT5823, an inhibitor of cGMP-dependent protein kinase (PKG) mimicked effects of L-NAME on the Ca2+ response. Transient receptor potential vanilloid 4 (TRPV4), an osmo- and mechanosensitive channel was expressed in the OHCs by means of immunohistochemistry. 4alpha-phorbol 12,13-didecanoate, a TRPV4 synthetic activator, induced NO production in OHCs. These results suggest that hyposmotic stimulation can induce NO production by the [Ca2+]i increase, which is presumably mediated by the activation of TRPV4 in OHCs. NO conversely inhibits the Ca2+ response via the NO-cGMP-PKG pathway by a feedback mechanism.

  3. Dynamic expression of Lgr6 in the developing and mature mouse cochlea

    Science.gov (United States)

    Zhang, Yanping; Chen, Yan; Ni, Wenli; Guo, Luo; Lu, Xiaoling; Liu, Liman; Li, Wen; Sun, Shan; Wang, Lei; Li, Huawei

    2015-01-01

    The Wnt/β-catenin signaling pathway plays important roles in mammalian inner ear development. Lgr5, one of the downstream target genes of the Wnt/β-catenin signaling pathway, has been reported to be a marker for inner ear hair cell progenitors. Lgr6 shares approximately 50% sequence homology with Lgr5 and has been identified as a stem cell marker in several organs. However, the detailed expression profiles of Lgr6 have not yet been investigated in the mouse inner ear. Here, we first used Lgr6-EGFP-Ires-CreERT2 mice to examine the spatiotemporal expression of Lgr6 protein in the cochlear duct during embryonic and postnatal development. Lgr6-EGFP was first observed in one row of prosensory cells in the middle and basal turn at embryonic day 15.5 (E15.5). From E18.5 to postnatal day 3 (P3), the expression of Lgr6-EGFP was restricted to the inner pillar cells (IPCs). From P7 to P15, the Lgr6-EGFP expression level gradually decreased in the IPCs and gradually increased in the inner border cells (IBCs). At P20, Lgr6-EGFP was only expressed in the IBCs, and by P30 Lgr6-EGFP expression had completely disappeared. Next, we demonstrated that Wnt/β-catenin signaling is required to maintain the Lgr6-EGFP expression in vitro. Finally, we demonstrated that the Lgr6-EGFP-positive cells isolated by flow cytometry could differentiate into myosin 7a-positive hair cells after 10 days in-culture, and this suggests that the Lgr6-positive cells might serve as the hair cell progenitor cells in the cochlea. PMID:26029045

  4. Dynamic Expression of Lgr6 in the Developing and Mature Mouse Cochlea

    Directory of Open Access Journals (Sweden)

    Yanping eZhang

    2015-05-01

    Full Text Available The Wnt/β-catenin signaling pathway plays important roles in mammalian inner ear development. Lgr5, one of the downstream target genes of the Wnt/β-catenin signaling pathway, has been reported to be a marker for inner ear hair cell progenitors. Lgr6 shares approximately 50% sequence homology with Lgr5 and has been identified as a stem cell marker in several organs. However, the detailed expression profiles of Lgr6 have not yet been investigated in the mouse inner ear. Here, we first used Lgr6-EGFP-Ires-CreERT2 mice to examine the spatiotemporal expression of Lgr6 protein in the cochlear duct during embryonic and postnatal development. Lgr6-EGFP was first observed in one row of prosensory cells in the middle and basal turn at embryonic day 15.5 (E15.5. From E18.5 to postnatal day 3 (P3, the expression of Lgr6-EGFP was restricted to the inner pillar cells (IPCs. From P7 to P15, the Lgr6-EGFP expression level gradually decreased in the IPCs and gradually increased in the inner border cells (IBCs. At P20, Lgr6-EGFP was only expressed in the IBCs, and by P30 Lgr6-EGFP expression had completely disappeared. Next, we demonstrated that Wnt/β-catenin signaling is required to maintain the Lgr6-EGFP expression in vitro. Finally, we demonstrated that the Lgr6-EGFP-positive cells isolated by flow cytometry could differentiate into myosin 7a-positive hair cells after 10 days in-culture, and this suggests that the Lgr6-positive cells might serve as the hair cell progenitor cells in the cochlea.

  5. Paul D. Sturkie: Avian cardiac physiologist.

    Science.gov (United States)

    Bello, Nicholas T; Cohick, Wendie S; McKeever, Kenneth H; Malinowski, Karyn

    2018-06-01

    Sturkie's Avian Physiology is a highly regarded textbook for the study of comparative poultry physiology. Less well known, however, is the contribution of Paul D. Sturkie (1909-2002) as a pioneer in the experimental physiology of avian species. His seminal research on the cardiovascular and hemodynamic controls of chickens and egg-laying hens had a notable impact on the poultry industry and breeding practices of farmers. The purpose of this article is to highlight the contributions and practical insights of Paul D. Sturkie to the field of poultry science.

  6. α-Synuclein deficiency and efferent nerve degeneration in the mouse cochlea: a possible cause of early-onset presbycusis.

    Science.gov (United States)

    Park, S N; Back, S A; Choung, Y H; Kim, H L; Akil, O; Lustig, L R; Park, K H; Yeo, S W

    2011-11-01

    Efferent nerves under the outer hair cells (OHCs) play a role in the protection of these cells from loud stimuli. Previously, we showed that cochlear α-synuclein expression is localized to efferent auditory synapses at the base of the OHCs. To prove our hypothesis that α-synuclein deficiency and efferent auditory deficit might be a cause of hearing loss, we compared the morphology of efferent nerve endings and α-synuclein expression within the cochleae of two mouse models of presbycusis. Comparative animal study of presbycusis. The C57BL/6J(C57) mouse strain, a well-known model of early-onset hearing loss, and the CBA mouse strain, a model of relatively late-onset hearing loss, were examined. Auditory brainstem responses and distortion product otoacoustic emissions were recorded, and cochlear morphology with efferent nerve ending was compared. Western blotting was used to examine α-synuclein expression in the cochlea. Compared with CBA mice, C57 mice showed earlier onset high-frequency hearing loss and decreased function in OHCs, especially within high-frequency regions. C57 mice demonstrated more severe pathologic changes within the cochlea, particularly within the basal turn, than CBA mice of the same age. Weaker α-synuclein and synaptophysin expression in the efferent nerve endings and cochlear homogenates in C57 mice was observed. Our results support the hypothesis that efferent nerve degeneration, possibly due to differential α-synuclein expression, is a potential cause of early-onset presbycusis. Further studies at the cellular level are necessary to verify our results. Copyright © 2011 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

  7. Age-related hearing loss: Aquaporin 4 gene expression changes in the mouse cochlea and auditory midbrain

    Science.gov (United States)

    Christensen, Nathan; D'Souza, Mary; Zhu, Xiaoxia; Frisina, Robert D.

    2009-01-01

    Presbycusis – age-related hearing loss, is the number one communication disorder, and one of the top three chronic medical conditions of our aged population. Aquaporins, particularly aquaporin 4 (Aqp4), are membrane proteins with important roles in water and ion flux across cell membranes, including cells of the inner ear and pathways of the brain used for hearing. To more fully understand the biological bases of presbycusis, 39 CBA mice, a well-studied animal model of presbycusis, underwent non-invasive hearing testing as a function of sound frequency (auditory brainstem response – ABR thresholds, and distortion-product otoacoustic emission – DPOAE magnitudes), and were clustered into four groups based on age and hearing ability. Aqp4 gene expression, as determined by genechip microarray analysis and quantitative real-time PCR, was compared to the young adult control group in the three older groups: middle aged with good hearing, old age with mild presbycusis, and old age with severe presbycusis. Linear regression and ANOVA showed statistically significant changes in Aqp4 gene expression and ABR and DPOAE hearing status in the cochlea and auditory midbrain – inferior colliculus. Down-regulation in the cochlea was seen, and an initial down-, then up-regulation was discovered for the inferior colliculus Aqp4 expression. It is theorized that these changes in Aqp4 gene expression represent an age-related disruption of ion flux in the fluids of the cochlea that are responsible for ionic gradients underlying sound transduction in cochlear hair cells necessary for hearing. In regard to central auditory processing at the level of the auditory midbrain, aquaporin gene expression changes may affect neurotransmitter cycling involving supporting cells, thus impairing complex sound neural processing with age. PMID:19070604

  8. Reciprocal synapses between outer hair cells and their afferent terminals: evidence for a local neural network in the mammalian cochlea.

    Science.gov (United States)

    Thiers, Fabio A; Nadol, Joseph B; Liberman, M Charles

    2008-12-01

    Cochlear outer hair cells (OHCs) serve both as sensory receptors and biological motors. Their sensory function is poorly understood because their afferent innervation, the type-II spiral ganglion cell, has small unmyelinated axons and constitutes only 5% of the cochlear nerve. Reciprocal synapses between OHCs and their type-II terminals, consisting of paired afferent and efferent specialization, have been described in the primate cochlea. Here, we use serial and semi-serial-section transmission electron microscopy to quantify the nature and number of synaptic interactions in the OHC area of adult cats. Reciprocal synapses were found in all OHC rows and all cochlear frequency regions. They were more common among third-row OHCs and in the apical half of the cochlea, where 86% of synapses were reciprocal. The relative frequency of reciprocal synapses was unchanged following surgical transection of the olivocochlear bundle in one cat, confirming that reciprocal synapses were not formed by efferent fibers. In the normal ear, axo-dendritic synapses between olivocochlear terminals and type-II terminals and/or dendrites were as common as synapses between olivocochlear terminals and OHCs, especially in the first row, where, on average, almost 30 such synapses were seen in the region under a single OHC. The results suggest that a complex local neuronal circuitry in the OHC area, formed by the dendrites of type-II neurons and modulated by the olivocochlear system, may be a fundamental property of the mammalian cochlea, rather than a curiosity of the primate ear. This network may mediate local feedback control of, and bidirectional communication among, OHCs throughout the cochlear spiral.

  9. Regenerable Carbon Filter, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A Regenerable Carbon Filter (RCF) is proposed for the removal of carbonaceous particulate matter produced in Environmental Control and Life Support (ECLS) processes....

  10. Sonic Hedgehog Initiates Cochlear Hair Cell Regeneration through Downregulation of Retinoblastoma Protein

    Science.gov (United States)

    Lu, Na; Chen, Yan; Wang, Zhengmin; Chen, Guoling; Lin, Qin; Chen, Zheng-Yi; Li, Huawei

    2013-01-01

    Cell cycle re-entry by cochlear supporting cells and/or hair cells is considered one of the best approaches for restoring hearing loss as a result of hair cell damage. To identify mechanisms that can be modulated to initiate cell cycle re-entry and hair cell regeneration, we studied the effect of activating the sonic hedgehog (Shh) pathway. We show that Shh signaling in postnatal rat cochleae damaged by neomycin leads to renewed proliferation of supporting cells and hair cells. Further, proliferating supporting cells are likely to transdifferentiate into hair cells. Shh treatment leads to inhibition of retinoblastoma protein (pRb) by increasing phosphorylated pRb and reducing retinoblastoma gene transcription. This results in upregulation of cyclins B1, D2, and D3, and CDK1. These results suggest that Shh signaling induces cell cycle re-entry in cochlear sensory epithelium and the production of new hair cells, in part by attenuating pRb function. This study provides an additional route to modulate pRb function with important implications in mammalian hair cell regeneration. PMID:23211596

  11. Analysis of Salient Feature Jitter in the Cochlea for Objective Prediction of Temporally Localized Distortion in Synthesized Speech

    Directory of Open Access Journals (Sweden)

    Wenliang Lu

    2009-01-01

    Full Text Available Temporally localized distortions account for the highest variance in subjective evaluation of coded speech signals (Sen (2001 and Hall (2001. The ability to discern and decompose perceptually relevant temporally localized coding noise from other types of distortions is both of theoretical importance as well as a valuable tool for deploying and designing speech synthesis systems. The work described within uses a physiologically motivated cochlear model to provide a tractable analysis of salient feature trajectories as processed by the cochlea. Subsequent statistical analysis shows simple relationships between the jitter of these trajectories and temporal attributes of the Diagnostic Acceptability Measure (DAM.

  12. Plasma skin regeneration technology.

    Science.gov (United States)

    Bogle, M A

    2006-09-01

    Plasma skin regeneration (PSR) technology uses energy delivered from plasma rather than light or radiofrequency. Plasma is the fourth state of matter in which electrons are stripped from atoms to form an ionized gas. The plasma is emitted in a millisecond pulse to deliver energy to target tissue upon contact without reliance on skin chromophores. The technology can be used at varying energies for different depths of effect, from superficial epidermal sloughing to deeper dermal heating. With the Portrait PSR device (Rhytec, Inc.) there are three treatment guidelines termed PSR1, PSR2, and PSR3. The PSR1 protocol uses a series of low-energy treatments (1.0,1.2 Joules) spaced 3 weeks apart. The PSR2 protocol uses one high-energy pass (3.0, 4.0 Joules) performed in a single treatment, and the PSR3 protocol uses two high-energy passes (3.0 4.0 Joules) performed in a single treatment. All protocols improve fine lines, textural irregularities, and dyspigmentation; however, skin tightening is probably more pronounced with the high-energy treatments.

  13. Regeneration mechanisms in Syllidae (Annelida)

    Science.gov (United States)

    Ribeiro, Rannyele P.

    2018-01-01

    Abstract Syllidae is one of the most species‐rich groups within Annelida, with a wide variety of reproductive modes and different regenerative processes. Syllids have striking ability to regenerate their body anteriorly and posteriorly, which in many species is redeployed during sexual (schizogamy) and asexual (fission) reproduction. This review summarizes the available data on regeneration in syllids, covering descriptions of regenerative mechanisms in different species as well as regeneration in relation to reproductive modes. Our survey shows that posterior regeneration is widely distributed in syllids, whereas anterior regeneration is limited in most of the species, excepting those reproducing by fission. The latter reproductive mode is well known for a few species belonging to Autolytinae, Eusyllinae, and Syllinae. Patterns of fission areas have been studied in these animals. Deviations of the regular regeneration pattern or aberrant forms such as bifurcated animals or individuals with multiple heads have been reported for several species. Some of these aberrations show a deviation of the bilateral symmetry and antero‐posterior axis, which, interestingly, can also be observed in the regular branching body pattern of some species of syllids. PMID:29721325

  14. Avian pox in Magellanic Penguins (Spheniscus magellanicus).

    Science.gov (United States)

    Kane, Olivia J; Uhart, Marcela M; Rago, Virginia; Pereda, Ariel J; Smith, Jeffrey R; Van Buren, Amy; Clark, J Alan; Boersma, P Dee

    2012-07-01

    Avian pox is an enveloped double-stranded DNA virus that is mechanically transmitted via arthropod vectors or mucosal membrane contact with infectious particles or birds. Magellanic Penguins (Spheniscus magellanicus) from two colonies (Punta Tombo and Cabo Dos Bahías) in Argentina showed sporadic, nonepidemic signs of avian pox during five and two of 29 breeding seasons (1982-2010), respectively. In Magellanic Penguins, avian pox expresses externally as wart-like lesions around the beak, flippers, cloaca, feet, and eyes. Fleas (Parapsyllus longicornis) are the most likely arthropod vectors at these colonies. Three chicks with cutaneous pox-like lesions were positive for Avipoxvirus and revealed phylogenetic proximity with an Avipoxvirus found in Black-browed Albatross (Thalassarche melanophrys) from the Falkland Islands in 1987. This proximity suggests a long-term circulation of seabird Avipoxviruses in the southwest Atlantic. Avian pox outbreaks in these colonies primarily affected chicks, often resulted in death, and were not associated with handling, rainfall, or temperature.

  15. Measuring steroid hormones in avian eggs

    NARCIS (Netherlands)

    Von Engelhardt, Nikolaus; Groothuis, Ton G. G.; Bauchinger, U; Goymann, W; JenniEiermann, S

    2005-01-01

    Avian eggs contain substantial levels of various hormones of maternal origin and have recently received a lot of interest, mainly from behavioral ecologists. These studies strongly depend on the measurement of egg hormone levels, but the method of measuring these levels has received little

  16. Measuring Steroid Hormones in Avian Eggs

    NARCIS (Netherlands)

    Engelhardt, Nikolaus von; Groothuis, Ton G.G.

    2005-01-01

    Avian eggs contain substantial levels of various hormones of maternal origin and have recently received a lot of interest, mainly from behavioral ecologists. These studies strongly depend on the measurement of egg hormone levels, but the method of measuring these levels has received little

  17. Avian Schistosomes and Outbreaks of Cercarial Dermatitis

    Science.gov (United States)

    Mikeš, Libor; Lichtenbergová, Lucie; Skála, Vladimír; Soldánová, Miroslava; Brant, Sara Vanessa

    2015-01-01

    SUMMARY Cercarial dermatitis (swimmer's itch) is a condition caused by infective larvae (cercariae) of a species-rich group of mammalian and avian schistosomes. Over the last decade, it has been reported in areas that previously had few or no cases of dermatitis and is thus considered an emerging disease. It is obvious that avian schistosomes are responsible for the majority of reported dermatitis outbreaks around the world, and thus they are the primary focus of this review. Although they infect humans, they do not mature and usually die in the skin. Experimental infections of avian schistosomes in mice show that in previously exposed hosts, there is a strong skin immune reaction that kills the schistosome. However, penetration of larvae into naive mice can result in temporary migration from the skin. This is of particular interest because the worms are able to migrate to different organs, for example, the lungs in the case of visceral schistosomes and the central nervous system in the case of nasal schistosomes. The risk of such migration and accompanying disorders needs to be clarified for humans and animals of interest (e.g., dogs). Herein we compiled the most comprehensive review of the diversity, immunology, and epidemiology of avian schistosomes causing cercarial dermatitis. PMID:25567226

  18. New Avian Hepadnavirus in Palaeognathous Bird, Germany

    NARCIS (Netherlands)

    Jo, Wendy K; Pfankuche, Vanessa M; Petersen, Henning; Frei, Samuel; Kummrow, Maya; Lorenzen, Stephan; Ludlow, Martin; Metzger, Julia; Baumgärtner, Wolfgang; Osterhaus, Albert; van der Vries, Erhard

    2017-01-01

    In 2015, we identified an avian hepatitis B virus associated with hepatitis in a group of captive elegant-crested tinamous (Eudromia elegans) in Germany. The full-length genome of this virus shares <76% sequence identity with other avihepadnaviruses. The virus may therefore be considered a new

  19. the Avian Park Service Learning Centre story

    African Journals Online (AJOL)

    The Ukwanda Centre for Rural Health (UCRH) opened in 2001, followed 10 years later by the establishment of the Ukwanda Rural Clinical School in one of the rural health districts of the Western Cape. This paper relates the journey of the Faculty with the underserviced community of Avian Park through the provision of ...

  20. Avian influenza A (H5N1)

    NARCIS (Netherlands)

    de Jong, Menno D.; Hien, Tran Tinh

    2006-01-01

    Since their reemergence in 2003, highly pathogenic avian influenza A (H5N1) viruses have reached endemic levels among poultry in several southeast Asian countries and have caused a still increasing number of more than 100 reported human infections with high mortality. These developments have ignited

  1. Vocal communication in an avian hybrid zone

    NARCIS (Netherlands)

    Hartog, Paula Maria den

    2008-01-01

    Avian vocalizations function in mate attraction and territorial defence. Vocalizations can act as behavioural barriers and play an important role in speciation processes. Hybrid zones illustrate behavioural barriers are not always impermeable and provide a natural laboratory to examine the role of

  2. Effects of drought on avian community structure

    Science.gov (United States)

    Thomas P. Albright; Anna M. Pidgeon; Chadwick D. Rittenhouse; Murray K. Clayton; Curtis H. Flather; Patrick D. Culbert; Brian D. Wardlow; Volker C. Radeloff

    2010-01-01

    Droughts are expected to become more frequent under global climate change. Avifauna depend on precipitation for hydration, cover, and food. While there are indications that avian communities respond negatively to drought, little is known about the response of birds with differing functional and behavioural traits, what time periods and indicators of drought are most...

  3. A glossary for avian conservation biology

    Science.gov (United States)

    Rolf R. Koford; John B. Dunning; Christine A. Ribic; Deborah M. Finch

    1994-01-01

    This glossary provides standard definitions for many of the terms used in avian conservation biology. We compiled these definitions to assist communication among researchers, managers, and others involved in the Neotropical Migratory Bird Conservation Program, also known as Partners in Flight. We used existing glossaries and recent literature to prepare this glossary....

  4. Serological diagnosis of avian influenza in poultry

    DEFF Research Database (Denmark)

    Comin, Arianna; Toft, Nils; Stegeman, Arjan

    2013-01-01

    Background The serological diagnosis of avian influenza (AI) can be performed using different methods, yet the haemagglutination inhibition (HI) test is considered the gold standard' for AI antibody subtyping. Although alternative diagnostic assays have been developed, in most cases, their accuracy...

  5. Avian Disease & Oncology Lab (ADOL) Research Update

    Science.gov (United States)

    Employing Genomics, Epigenetics, and Immunogenetics to Control Diseases Induced by Avian Tumor Viruses - Gene expression is a major factor accounting for phenotypic variation. Taking advantage of allele-specific expression (ASE) screens, we found the use of genetic markers was superior to traditiona...

  6. Solar activity affects avian timing of reproduction

    NARCIS (Netherlands)

    Visser, M.E.; Sanz, J.J.

    2009-01-01

    Avian timing of reproduction is strongly affected by ambient temperature. Here we show that there is an additional effect of sunspots on laying date, from five long-term population studies of great and blue tits (Parus major and Cyanistes caeruleus), demonstrating for the first time that solar

  7. Expression of tumor necrosis factor-α and interleukin-1β genes in the cochlea and inferior colliculus in salicylate-induced tinnitus

    Directory of Open Access Journals (Sweden)

    Chen Jin-Cherng

    2011-04-01

    Full Text Available Abstract Background Changes in the gene expressions for tumor necrosis factor-α (TNF-α and/or interleukin-1β (IL-1β during tinnitus have not been previously reported. We evaluated tinnitus and mRNA expression levels of TNF-α, IL-1β, and N-methyl D-aspartate receptor subunit 2B (NR2B genes in cochlea and inferior colliculus (IC of mice after intraperitoneal injections of salicylate. Methods Forty-eight 3-month-old male SAMP8 mice were randomly and equally divided into two groups: salicylate-treated and saline-treated. All mice were trained to perform an active avoidance task for 5 days. Once conditioned, an active avoidance task was performed 2 hours after daily intraperitoneal injections of saline, either alone or containing 300 mg/kg sodium salicylate. Total numbers of times (tinnitus score the mice climbed during the inter-trial silent period for 10 trials were recorded daily for 4 days (days 7 to 10, and then mice were euthanized for determination of mRNA expression levels of TNF-α, IL-1β, and NR2B genes in cochlea and IC at day 10. Results Tinnitus scores increased in response to daily salicylate treatments. The mRNA expression levels of TNF-α increased significantly for the salicylate-treated group compared to the control group in both cochlea (1.89 ± 0.22 vs. 0.87 ± 0.07, P p = 0.0040. mRNA expression levels for the IL-1β gene also increased significantly in the salicylate group compared to the control group in both cochlea (3.50 ± 1.05 vs. 2.80 ± 0.28, p versus 1.24 ± 0.52, p = 0.0013. Linear regression analysis revealed a significant positive association between tinnitus scores and expression levels of TNF-α, IL-1β, and NR2B genes in cochlea and IC. In addition, expression levels of the TNF-α gene were positively correlated with those of the NR2Bgene in both cochlea and IC; whereas, the expression levels of the IL-1β gene was positively correlated with that of the NR2B gene in IC, but not in cochlea. Conclusion We

  8. The structural and functional differentiation of hair cells in a lizard's basilar papilla suggests an operational principle of amniote cochleas.

    Science.gov (United States)

    Chiappe, M Eugenia; Kozlov, Andrei S; Hudspeth, A J

    2007-10-31

    The hair cells in the mammalian cochlea are of two distinct types. Inner hair cells are responsible for transducing mechanical stimuli into electrical responses, which they forward to the brain through a copious afferent innervation. Outer hair cells, which are thought to mediate the active process that sensitizes and tunes the cochlea, possess a negligible afferent innervation. For every inner hair cell, there are approximately three outer hair cells, so only one-quarter of the hair cells directly deliver information to the CNS. Although this is a surprising feature for a sensory system, the occurrence of a similar innervation pattern in birds and crocodilians suggests that the arrangement has an adaptive value. Using a lizard with highly developed hearing, the tokay gecko, we demonstrate in the present study that the same principle operates in a third major group of terrestrial animals. We propose that the differentiation of hair cells into signaling and amplifying classes reflects incompatible strategies for the optimization of mechanoelectrical transduction and of an active process based on active hair-bundle motility.

  9. Effect of c-myc on the ultrastructural structure of cochleae in guinea pigs with noise induced hearing loss

    International Nuclear Information System (INIS)

    Han, Yu; Zhong, Cuiping; Hong, Liu; Wang, Ye; Qiao, Li; Qiu, Jianhua

    2009-01-01

    Noise over-stimulation may induce hair cells loss and hearing deficit. The c-myc oncogene is a major regulator for cell proliferation, growth, and apoptosis. However, the role of this gene in the mammalian cochlea is still unclear. The study was designed to firstly investigate its function under noise condition, from the aspect of cochlear ultrastructural changes. We had established the adenoviral vector of c-myc gene and delivered the adenovirus suspension into the scala tympani of guinea pigs 4 days before noise exposure. The empty adenoviral vectors were injected as control. Then, all subjects were exposed to 4-kHz octave-band noise at 110 dB SPL for 8 h/day, 3 days consecutively. Auditory thresholds were assessed by auditory brainstem response, prior to and 7 days following noise exposure. On the seventh days after noise exposure, the cochlear sensory epithelia surface was observed microscopically and the cochleae were taken to study the ultrastructural changes. The results indicated that auditory threshold shift after noise exposure was higher in the ears treated with Ad.EGFP than that treated with Ad.c-myc-EGFP. Stereocilia loss and the disarrangement of outer hair cells were observed, with greater changes found in the Ad.EGFP group. Also, the ultrastructure changes were severe in the Ad.EGFP group, but not obvious in the Ad.c-myc-EGFP group. Therefore, c-myc gene might play an unexpected role in hearing functional and morphological protection from acoustic trauma.

  10. Effect of c-myc on the ultrastructural structure of cochleae in guinea pigs with noise induced hearing loss

    Energy Technology Data Exchange (ETDEWEB)

    Han, Yu; Zhong, Cuiping [Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 Shaanxi Province (China); Hong, Liu [First Division of Digestive Diseases, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 Shaanxi Province (China); Wang, Ye; Qiao, Li [Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 Shaanxi Province (China); Qiu, Jianhua, E-mail: qiujh@fmmu.edu.cn [Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 Shaanxi Province (China)

    2009-12-18

    Noise over-stimulation may induce hair cells loss and hearing deficit. The c-myc oncogene is a major regulator for cell proliferation, growth, and apoptosis. However, the role of this gene in the mammalian cochlea is still unclear. The study was designed to firstly investigate its function under noise condition, from the aspect of cochlear ultrastructural changes. We had established the adenoviral vector of c-myc gene and delivered the adenovirus suspension into the scala tympani of guinea pigs 4 days before noise exposure. The empty adenoviral vectors were injected as control. Then, all subjects were exposed to 4-kHz octave-band noise at 110 dB SPL for 8 h/day, 3 days consecutively. Auditory thresholds were assessed by auditory brainstem response, prior to and 7 days following noise exposure. On the seventh days after noise exposure, the cochlear sensory epithelia surface was observed microscopically and the cochleae were taken to study the ultrastructural changes. The results indicated that auditory threshold shift after noise exposure was higher in the ears treated with Ad.EGFP than that treated with Ad.c-myc-EGFP. Stereocilia loss and the disarrangement of outer hair cells were observed, with greater changes found in the Ad.EGFP group. Also, the ultrastructure changes were severe in the Ad.EGFP group, but not obvious in the Ad.c-myc-EGFP group. Therefore, c-myc gene might play an unexpected role in hearing functional and morphological protection from acoustic trauma.

  11. Volumetric label-free imaging and 3D reconstruction of mammalian cochlea based on two-photon excitation fluorescence microscopy

    International Nuclear Information System (INIS)

    Zhang, Xianzeng; Zhan, Zhenlin; Xie, Shusen; Geng, Yang; Ye, Qing

    2013-01-01

    The visualization of the delicate structure and spatial relationship of intracochlear sensory cells has relied on the laborious procedures of tissue excision, fixation, sectioning and staining for light and electron microscopy. Confocal microscopy is advantageous for its high resolution and deep penetration depth, yet disadvantageous due to the necessity of exogenous labeling. In this study, we present the volumetric imaging of rat cochlea without exogenous dyes using a near-infrared femtosecond laser as the excitation mechanism and endogenous two-photon excitation fluorescence (TPEF) as the contrast mechanism. We find that TPEF exhibits strong contrast, allowing cellular and even subcellular resolution imaging of the cochlea, differentiating cell types, visualizing delicate structures and the radial nerve fiber. Our results further demonstrate that 3D reconstruction rendered with z-stacks of optical sections enables better revealment of fine structures and spatial relationships, and easily performed morphometric analysis. The TPEF-based optical biopsy technique provides great potential for new and sensitive diagnostic tools for hearing loss or hearing disorders, especially when combined with fiber-based microendoscopy. (paper)

  12. Thyroid hormone is required for the pruning of afferent type II spiral ganglion neurons in the mouse cochlea

    Science.gov (United States)

    Sundaresan, Srividya; Balasubbu, Suganthalakshmi; Mustapha, Mirna

    2015-01-01

    Afferent connections to the sensory inner and outer hair cells in the cochlea refine and functionally mature during the thyroid hormone (TH)- critical period of inner ear development that occurs perinatally in rodents. In this study, we investigated the effects of hypothyroidism on afferent type II innervation to outer hair cells (OHCs) using the Snell dwarf mouse (Pit1dw). Using a transgenic approach to specifically label type II spiral ganglion neurons, we found that a lack of TH causes persistence of excess type II SGN connections to the OHCs, as well as continued expression of the hair cell functional marker, otoferlin, in the OHCs beyond the maturation period. We also observed a concurrent delay in efferent attachment to the OHCs. Supplementing with TH during the early postnatal period from postnatal day (P) 3 to P4 reversed the defect in type II SGN pruning but did not alter otoferlin expression. Our results show that hypothyroidism causes a defect in the large-scale pruning of afferent type II spiral ganglion neurons in the cochlea, and a delay in efferent attachment and the maturation of otoferlin expression. Our data suggest that the state of maturation of hair cells, as determined by otoferlin expression, may not regulate the pruning of their afferent innervation. PMID:26592716

  13. A Bio-Realistic Analog CMOS Cochlea Filter With High Tunability and Ultra-Steep Roll-Off.

    Science.gov (United States)

    Wang, Shiwei; Koickal, Thomas Jacob; Hamilton, Alister; Cheung, Rebecca; Smith, Leslie S

    2015-06-01

    This paper presents the design and experimental results of a cochlea filter in analog very large scale integration (VLSI) which highly resembles physiologically measured response of the mammalian cochlea. The filter consists of three specialized sub-filter stages which respectively provide passive response in low frequencies, actively tunable response in mid-band frequencies and ultra-steep roll-off at transition frequencies from pass-band to stop-band. The sub-filters are implemented in balanced ladder topology using floating active inductors. Measured results from the fabricated chip show that wide range of mid-band tuning including gain tuning of over 20 dB, Q factor tuning from 2 to 19 as well as the bio-realistic center frequency shift are achieved by adjusting only one circuit parameter. Besides, the filter has an ultra-steep roll-off reaching over 300 dB/dec. By changing biasing currents, the filter can be configured to operate with center frequencies from 31 Hz to 8 kHz. The filter is 9th order, consumes 59.5 ∼ 90.0 μW power and occupies 0.9 mm2 chip area. A parallel bank of the proposed filter can be used as the front-end in hearing prosthesis devices, speech processors as well as other bio-inspired auditory systems owing to its bio-realistic behavior, low power consumption and small size.

  14. Direct measurement of cerebrospinal fluid pressure through the cochlea in a congenitally deaf child with Mondini dysplasia undergoing cochlear implantation.

    Science.gov (United States)

    Graham, J M; Ashcroft, P

    1999-03-01

    Perilymph/cerebrospinal fluid (CSF) "gushers" may occur at cochleostomy during cochlear implant surgery, particularly in patients with congenital cochlear duct malformation in which CSF in the internal auditory meatus is in direct communication with the perilymphatic space in the cochlea. The object of the study was to measure the pressure and flow of a CSF gusher at cochleostomy. The design was a preoperative pressure measurement. The setting was a multidisciplinary cochlear implant program. A 4-year-old girl with bilateral Mondini deformity undergoing cochlear implantation was studied. A size 23 FG intravenous cannula was inserted into the cochlea and connected to a pediatric drip set to form an improvised manometer. Intracochlear fluid pressure was measured at 14 cm H2O, equivalent to the normal CSF pressure that would be recorded in a child of this age at lumbar puncture. An indirect measurement of the likely size of the CSF/perilymph defect was made. This technique may allow better assessment of the risk of postoperative CSF leakage and meningitis. This simple technique of measuring the pressure in a perilymph gusher can be used to assess the need for careful sealing of the cochleostomy, to measure the reduction in pressure produced by head elevation or a spinal drain, and to assess the probable size of a defect in the lamina cribrosa.

  15. Expression pattern of wolframin, the WFS1 (Wolfram syndrome-1 gene) product, in common marmoset (Callithrix jacchus) cochlea.

    Science.gov (United States)

    Suzuki, Noriomi; Hosoya, Makoto; Oishi, Naoki; Okano, Hideyuki; Fujioka, Masato; Ogawa, Kaoru

    2016-08-03

    Wolfram syndrome is an autosomal recessive disorder of the neuroendocrine system, known as DIDMOAD (Diabetes Insipidus, Diabetes Mellitus, Optic Atrophy and Deafness) syndrome, and considered an endoplasmic reticulum disease. Patients show mutations in WFS1, which encodes the 890 amino acid protein wolframin. Although Wfs1 knockout mice develop diabetes, their hearing level is completely normal. In this study, we examined the expression of wolframin in the cochlea of a nonhuman primate common marmoset (Callithrix jacchus) to elucidate the discrepancy in the phenotype between species and the pathophysiology of Wolfram syndrome-associated deafness. The marmoset cochlea showed wolframin immunoreactivity not only in the spiral ligament type I fibrocytes, spiral ganglion neurons, outer hair cells, and supporting cells, but in the stria vascularis basal cells, where wolframin expression was not observed in the previous mouse study. Considering the absence of the deafness phenotype in Wfs1 knockout mice, the expression of wolframin in the basal cells of primates may play an essential role in the maintenance of hearing. Elucidating the function of wolframin protein in the basal cells of primates would be essential for understanding the pathogenesis of hearing loss in patients with Wolfram syndrome, which may lead to the discovery of new therapeutics.

  16. Expression of EFR3A in the mouse cochlea during degeneration of spiral ganglion following hair cell loss.

    Directory of Open Access Journals (Sweden)

    Chen Nie

    Full Text Available Retrograde degeneration of spiral ganglion cells in the cochlea following hair cell loss is similar to dying back in pathology. The EFR3A gene has recently been discovered to be involved in the pathogenesis of dying back. The relationship of EFR3A and spiral ganglion degeneration, however, was rarely investigated. In this study, we destroyed the hair cells of the mouse cochlea by co-administration of kanamycin and furosemide and then investigated the EFR3A expression during the induced spiral ganglion cell degeneration. Our results revealed that co-administration of kanamycin and furosemide quickly induced hair cell loss in the C57BL/6J mice and then resulted in progressive degeneration of the spiral ganglion beginning at day 5 following drug administration. The number of the spiral ganglion cells began to decrease at day 15. The expression of EFR3A increased remarkably in the spiral ganglion at day 5 and then decreased to near normal level within the next 10 days. Our study suggested that the change of EFR3A expression in the spiral ganglion was coincident with the time of the spiral ganglion degeneration, which implied that high expression of EFR3A may be important to prompt initiation of spiral ganglion degeneration following hair cell loss.

  17. [The expression and significance of VIP and its receptor in the cochlea of different degrees of chronic alcoholism rats].

    Science.gov (United States)

    Feng, Jing; Liu, Haibing

    2015-07-01

    To determine whether chronic alcoholism alters the expression levels of Vasoactive intestinal polypeptide (VIP) and its receptor (VIPR1) in the cochlea of chronic alcoholism rats. We measured their expression levels in 30 SD rats, in which we created models of different degrees of chronic alcoholism. We investigated the presence of the mRNA of VIP in the cochlea of chronic alcoholism rats and controls by reverse transcription-polymerase chain reaction (RT-PCR) method. We investigated the presence of proteins of VIPR1 in poisoned rats and controls by western blot. We also evaluated the local distribution of VIP cells by immunohistochemistry. We found that the levels of VIP and VIPR1 were downregulated in the chronic alcoholism groups compared to the controls group. The differences in some expression levels were significant different between chronic alcoholism rats and control rats. Moreover, at different degrees of alcohol poisoning in rats, the contents of VIP and VIPR1 differed. Decreased levels of VIP and VIPR1 were detected in the deep chronic alcoholism group compared to the group with low-degree poisoning (P 0.05). These results suggest that VIP and VIPR1 play an important role in the auditory function in rats with chronic alcoholism. Chronic alcoholism may cause a peptide hormone secretion imbalance in the auditory system, eventually leading to hearing loss.

  18. [Identifying transcription factors involved in Arabidopsis adventious shoot regeneration by RNA-Seq technology].

    Science.gov (United States)

    Wang, Xingchun; Chen, Zhao; Fan, Juan; He, Miaomiao; Han, Yuanhuai; Yang, Zhirong

    2015-04-01

    Transcriptional regulation is one of the major regulations in plant adventious shoot regeneration, but the exact mechanism remains unclear. In our study, the RNA-seq technology based on the IlluminaHiSeq 2000 sequencing platform was used to identify differentially expressed transcription factor (TF) encoding genes during callus formation stage and adventious shoot regeneration stage between wild type and adventious shoot formation defective mutant be1-3 and during the transition from dedifferentiation to redifferentiation stage in wildtype WS. Results show that 155 TFs were differentially expressed between be1-3 mutant and wild type during callus formation, of which 97 genes were up-regulated, and 58 genes were down-regulated; and that 68 genes were differentially expressed during redifferentiation stage, with 40 genes up-regulated and 28 genes down-regulated; whereas at the transition stage from dedifferentiation to redifferention in WS wild type explants, a total of 231 differentially expressed TF genes were identified, including 160 up-regualted genes and 71 down-regulated genes. Among these TF genes, the adventious shoot related transcription factor 1 (ART1) gene encoding a MYB-related (v-myb avian myeloblastosis viral oncogene homolog) TF, was up-regulated 3 217 folds, and was the highest up-regulated gene during be1-3 callus formation. Over expression of the ART1 gene caused defects in callus formation and shoot regeneration and inhibited seedling growth, indicating that the ART1 gene is a negative regulator of callus formation and shoot regeneration. This work not only enriches our knowledge about the transcriptional regulation mechanism of adventious shoot regeneration, but also provides valuable information on candidate TF genes associated with adventious shoot regeneration for future research.

  19. [Guided bone regeneration: general survey].

    Science.gov (United States)

    Cosyn, Jan; De Bruyn, Hugo

    2009-01-01

    The principle of 'guided bone regeneration' was first described in 1988 on the basis of animal-experimental data. Six weeks after transmandibular defects had been created and protected by non-resorbable teflonmembranes, complete bone regeneration was found. The technique was based on the selective repopulation of the wound: every infiltration of cells outside the neighbouring bone tissue was prevented by the application of the membrane. Additional animal experiments showed that guided bone regeneration was a viable treatment option for local bone defects surrounding dental implants. Clinical practice, however, showed that premature membrane exposure was a common complication, which was responsible for a tremendous reduction in regenerated bone volume. In addition, a second surgical intervention was always necessary to remove the membrane. As a result, resorbable alternatives were developed. Since these are less rigid, bone fillers are usually used simultaneously. These comprise autogenous bone chips and bone substitutes from allogenic or xenogenic origine. Also alloplastic materials could be used for this purpose. Based on their characteristics this article provides an overview of the biomaterials that could be considered for guided bone regeneration. Specific attention goes to their application in clinical practice.

  20. Hair cell regeneration or the expression of related factors that regulate the fate specification of supporting cells in the cochlear ducts of embryonic and posthatch chickens.

    Science.gov (United States)

    Jiang, Lingling; Jin, Ran; Xu, Jincao; Ji, Yubin; Zhang, Meiguang; Zhang, Xuebo; Zhang, Xinwen; Han, Zhongming; Zeng, Shaoju

    2016-02-01

    Hair cells in posthatch chickens regenerate spontaneously through mitosis or the transdifferentiation of supporting cells in response to antibiotic injury. However, how embryonic chicken cochleae respond to antibiotic treatment remains unknown. This study is the first to indicate that unlike hair cells in posthatch chickens, the auditory epithelium was free from antibiotic injury (25-250 mg gentamicin/kg) in embryonic chickens, although FITC-conjugated gentamicin actually reached embryonic hair cells. Next, we examined and counted the cells and performed labeling for BrdU, Sox2, Atoh1/Math1, PV or p27(kip1) (triple or double labeling) in the injured cochlea ducts after gentamicin treatment at 2 h (h), 15 h, 24 h, 2 days (d), 3 d and 7 d after BrdU treatment in posthatch chickens. Our results indicated that following gentamicin administration, proliferating cells (BrdU+) were labeled for Atoh1/Math1 in the damaged areas 3d after gentamicin administration, whereas hair cells (PV+) renewed through mitosis (BrdU+) or direct transdifferentiation (BrdU-) were evident only after 5 d of gentamicin administration. In addition, Sox2 expression was up-regulated in triggered supporting cells at an early stage of regeneration, but stopped at the advent of mature hair cells. Our study also indicated that p27(kip1) was expressed in both hair cells and supporting cells but was down-regulated in a subgroup of the supporting cells that gave rise to hair cells. These data and the obtained dynamic changes of the cells labeled for BrdU, Sox2, Atoh1/Math1, PV or p27(kip1) are useful for understanding supporting cell behaviors and their fate specification during hair cell regeneration. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Microwave regeneration of molecular sieves

    International Nuclear Information System (INIS)

    Singh, V.P.

    1984-05-01

    Molecular sieve driers have been included in the design of tritium handling systems for fusion reactors. In these systems there is a need to maintain extremely low exit dew points from the driers as well as a capability to rapidly reduce tritium concentrations following an accident. The required capacity of the driers is very high. The conventional method of regenerating these sieves after a water adsorption cycle is with hot air. However, because water is rapidly heated by microwave energy, this technology may be suitable for decreasing the bed regeneration time and hence may allow reduced capital and operating costs associated with a smaller bed. The present study was conducted to obtain preliminary information on the technical feasibility of regenerating molecular sieves with microwave energy. The study concentrated on Type 4A molecular sieve with a few tests on Type 13X sieve and also a silica gel adsorbent

  2. Regenerator cross arm seal assembly

    Science.gov (United States)

    Jackman, Anthony V.

    1988-01-01

    A seal assembly for disposition between a cross arm on a gas turbine engine block and a regenerator disc, the seal assembly including a platform coextensive with the cross arm, a seal and wear layer sealingly and slidingly engaging the regenerator disc, a porous and compliant support layer between the platform and the seal and wear layer porous enough to permit flow of cooling air therethrough and compliant to accommodate relative thermal growth and distortion, a dike between the seal and wear layer and the platform for preventing cross flow through the support layer between engine exhaust and pressurized air passages, and air diversion passages for directing unregenerated pressurized air through the support layer to cool the seal and wear layer and then back into the flow of regenerated pressurized air.

  3. On avian influenza epidemic models with time delay.

    Science.gov (United States)

    Liu, Sanhong; Ruan, Shigui; Zhang, Xinan

    2015-12-01

    After the outbreak of the first avian influenza A virus (H5N1) in Hong Kong in 1997, another avian influenza A virus (H7N9) crossed the species barrier in mainland China in 2013 and 2014 and caused more than 400 human cases with a death rate of nearly 40%. In this paper, we take account of the incubation periods of avian influenza A virus and construct a bird-to-human transmission model with different time delays in the avian and human populations combining the survival probability of the infective avian and human populations at the latent time. By analyzing the dynamical behavior of the model, we obtain a threshold value for the prevalence of avian influenza and investigate local and global asymptotical stability of equilibria of the system.

  4. Avian Plasmodium in Eastern Austrian mosquitoes.

    Science.gov (United States)

    Schoener, Ellen; Uebleis, Sarah Susanne; Butter, Julia; Nawratil, Michaela; Cuk, Claudia; Flechl, Eva; Kothmayer, Michael; Obwaller, Adelheid G; Zechmeister, Thomas; Rubel, Franz; Lebl, Karin; Zittra, Carina; Fuehrer, Hans-Peter

    2017-09-29

    Insect vectors, namely mosquitoes (Diptera: Culicidae), are compulsory for malaria parasites (Plasmodium spp.) to complete their life cycle. Despite this, little is known about vector competence of different mosquito species for the transmission of avian malaria parasites. In this study, nested PCR was used to determine Plasmodium spp. occurrence in pools of whole individuals, as well as the diversity of mitochondrial cytochrome b gene sequences in wild-caught mosquitoes sampled across Eastern Austria in 2013-2015. A total of 45,749 mosquitoes in 2628 pools were collected, of which 169 pools (6.43%) comprising 9 mosquito species were positive for avian Plasmodium, with the majority of positives in mosquitoes of Culex pipiens s.l./Culex torrentium. Six different avian Plasmodium lineages were found, the most common were Plasmodium vaughani SYAT05, Plasmodium sp. Linn1 and Plasmodium relictum SGS1. In 2014, mosquitoes of the Culex pipiens complex were genetically identified and Culex pipiens f. pipiens presented with the highest number of avian Plasmodium positives (n = 37; 16.74%). Despite this, the minimum infection rate (MIR) was highest in Culex torrentium (5.36%) and Culex pipiens f. pipiens/f. molestus hybrids (5.26%). During 2014 and 2015, seasonal and annual changes in Plasmodium lineage distribution were also observed. In both years P. vaughani SYAT05 dominated at the beginning of the sampling period to be replaced later in the year by P. relictum SGS1 (2014) and Plasmodium sp. Linn1 (2015). This is the first large-scale study of avian Plasmodium parasites in Austrian mosquitoes. These results are of special interest, because molecular identification of the taxa of the Cx. pipiens complex and Cx. torrentium enabled the determination of Plasmodium prevalence in the different mosquito taxa and hybrids of this complex. Since pools of whole insects were used, it is not possible to assert any vector competence in any of the examined mosquitoes, but the results

  5. "We Was Regenerated Out": Regeneration, Recycling and Devaluing Communities

    Directory of Open Access Journals (Sweden)

    Luna Glucksberg

    2014-12-01

    Full Text Available This article looks at well documented processes of urban regeneration and community displacement in the inner-city through an innovative anthropological perspective focused on concepts of waste and value. Using the notion of symbolic devaluation of the working classes developed by Skeggs (1997; 2004, it traces their exclusion from recycling practices while at the same time the estates they live on are being regenerated. Raising questions about the parallels and contradictions between regeneration and recycling, it shows how symbolic devaluation of specifi c areas and their inhabitants are necessary precursors of the physical demolition and removal that characterize regeneration processes. Through an ethnographic approach, the deep connections between people and their waste, and people as waste, are exposed and questioned, showing how valuable middle class selves are produced through appropriate waste management procedures, i.e. individualized recycling, while inner-city, estate dwellers are remade into uncaring, unworthy citizens who cannot take part in this value-producing circuit.

  6. Plant Regeneration and Genetic Transformation in Eggplant ...

    African Journals Online (AJOL)

    Dr Harmander Gill

    2014-02-05

    Feb 5, 2014 ... Review. Plant regeneration in eggplant (Solanum melongena L.): A review ... and development of somatic hybrids, efficient plant regeneration ... was first reported in eggplant from immature seed embryos .... Hormone free MS.

  7. Skeletal muscle regeneration is modulated by inflammation

    Directory of Open Access Journals (Sweden)

    Wenjun Yang

    2018-04-01

    Full Text Available Skeletal muscle regeneration is a complex process orchestrated by multiple steps. Recent findings indicate that inflammatory responses could play central roles in bridging initial muscle injury responses and timely muscle injury reparation. The various types of immune cells and cytokines have crucial roles in muscle regeneration process. In this review, we briefly summarise the functions of acute inflammation in muscle regeneration. The translational potential of this article: Immune system is closely relevant to the muscle regeneration. Understanding the mechanisms of inflammation in muscle regeneration is therefore critical for the development of effective regenerative, and therapeutic strategies in muscular disorders. This review provides information for muscle regeneration research regarding the effects of inflammation on muscle regeneration. Keywords: Chronic muscle disorders, Cytokines, Immune cells, Inflammation, Muscle regeneration, Muscle stem cells

  8. Fractalkine Signaling Regulates Macrophage Recruitment into the Cochlea and Promotes the Survival of Spiral Ganglion Neurons after Selective Hair Cell Lesion.

    Science.gov (United States)

    Kaur, Tejbeer; Zamani, Darius; Tong, Ling; Rubel, Edwin W; Ohlemiller, Kevin K; Hirose, Keiko; Warchol, Mark E

    2015-11-11

    Macrophages are recruited into the cochlea in response to injury caused by acoustic trauma or ototoxicity, but the nature of the interaction between macrophages and the sensory structures of the inner ear remains unclear. The present study examined the role of fractalkine signaling in regulating the injury-evoked behavior of macrophages following the selective ablation of cochlear hair cells. We used a novel transgenic mouse model in which the human diphtheria toxin receptor (huDTR) is selectively expressed under the control of Pou4f3, a hair cell-specific transcription factor. Administration of diphtheria toxin (DT) to these mice resulted in nearly complete ablation of cochlear hair cells, with no evident pathology among supporting cells, spiral ganglion neurons, or cells of the cochlear lateral wall. Hair cell death led to an increase in macrophages associated with the sensory epithelium of the cochlea. Their numbers peaked at 14 days after DT and then declined at later survival times. Increased macrophages were also observed within the spiral ganglion, but their numbers remained elevated for (at least) 56 d after DT. To investigate the role of fractalkine signaling in macrophage recruitment, we crossed huDTR mice to a mouse line that lacks expression of the fractalkine receptor (CX3CR1). Disruption of fractalkine signaling reduced macrophage recruitment into both the sensory epithelium and spiral ganglion and also resulted in diminished survival of spiral ganglion neurons after hair cell death. Our results suggest a fractalkine-mediated interaction between macrophages and the neurons of the cochlea. It is known that damage to the inner ear leads to recruitment of inflammatory cells (macrophages), but the chemical signals that initiate this recruitment and the functions of macrophages in the damaged ear are unclear. Here we show that fractalkine signaling regulates macrophage recruitment into the cochlea and also promotes the survival of cochlear afferents after

  9. Avian use of Norris Hill Wind Resource Area, Montana

    Energy Technology Data Exchange (ETDEWEB)

    Harmata, A.; Podruzny, K.; Zelenak, J. [Montana State Univ., Bozeman, MT (United States). Biology Dept.

    1998-07-01

    This document presents results of a study of avian use and mortality in and near a proposed wind resource area in southwestern Montana. Data collected in autumn 1995 through summer 1996 represented preconstruction condition; it was compiled, analyzed, and presented in a format such that comparison with post-construction data would be possible. The primary emphasis of the study was recording avian migration in and near the wind resource area using state-of-the-art marine surveillance radar. Avian use and mortality were investigated during the breeding season by employing traditional avian sampling methods, radiotelemetry, radar, and direct visual observation. 61 figs., 34 tabs.

  10. Direct administration of 2-Hydroxypropyl-Beta-Cyclodextrin into guinea pig cochleae: Effects on physiological and histological measurements.

    Directory of Open Access Journals (Sweden)

    J T Lichtenhan

    Full Text Available 2-Hydroxypropyl-Beta-Cyclodextrin (HPβCD can be used to treat Niemann-Pick type C disease, Alzheimer's disease, and atherosclerosis. But, a consequence is that HPβCD can cause hearing loss. HPβCD was recently found to be toxic to outer hair cells (OHCs in the organ of Corti. Previous studies on the chronic effects of in vivo HPβCD toxicity did not know the intra-cochlear concentration of HPβCD and attributed variable effects on OHCs to indirect drug delivery to the cochlea. We studied the acute effects of known HPβCD concentrations administered directly into intact guinea pig cochleae. Our novel approach injected solutions through pipette sealed into scala tympani in the cochlear apex. Solutions were driven along the length of the cochlear spiral toward the cochlear aqueduct in the base. This method ensured that therapeutic levels were achieved throughout the cochlea, including those regions tuned to mid to low frequencies and code speech vowels and background noise. A wide variety of measurements were made. Results were compared to measurements from ears treated with the HPβCD analog methyl-β-cyclodextrin (MβCD, salicylate that is well known to attenuate the gain of the cochlear amplifier, and injection of artificial perilymph alone (controls. Histological data showed that OHCs appeared normal after treatment with a low dose of HPβCD, and physiological data was consistent with attenuation of cochlear amplifier gain and disruption of non-linearity associated with transferring acoustic sound into neural excitation, an origin of distortion products that are commonly used to objectively assess hearing and hearing loss. A high dose of HPβCD caused sporadic OHC losses and markedly affected all physiologic measurements. MβCD caused virulent destruction of OHCs and physiologic responses. Toxicity of HPβCD to OHC along the cochlear length is variable even when a known intra-cochlear concentration is administered, at least for the duration

  11. Infrasound and the avian navigational map.

    Science.gov (United States)

    Hagstrum, J T

    2000-04-01

    Birds can navigate accurately over hundreds to thousands of kilometres, and this ability of homing pigeons is the basis for a worldwide sport. Compass senses orient avian flight, but how birds determine their location in order to select the correct homeward bearing (map sense) remains a mystery. Also mysterious are rare disruptions of pigeon races in which most birds are substantially delayed and large numbers are lost. Here, it is shown that in four recent pigeon races in Europe and the northeastern USA the birds encountered infrasonic (low-frequency acoustic) shock waves from the Concorde supersonic transport. An acoustic avian map is proposed that consists of infrasonic cues radiated from steep-sided topographic features; the source of these signals is microseisms continuously generated by interfering oceanic waves. Atmospheric processes affecting these infrasonic map cues can explain perplexing experimental results from pigeon releases.

  12. A bibliography of references to avian botulism

    Science.gov (United States)

    Allen, Jack E.; Wilson, Sonoma S.

    1977-01-01

    This bibliography, first compiled in 1970 in response to many requests for information on avian botulism, has been updated to include the literature published through 1975.In general, only articles dealing primarily with the avian disease are included, as opposed to those concerned with various aspects of the biology of Clostridium botulinum, either type C or type E. A few exceptions, such as Bengton’s report of the first isolation and description of the type C organism, are included for their historical interest. Progress reports and other administrative documents not available for distribution or request are excluded, as are textbook accounts, which are generally summaries of work published elsewhere.Although Mr. Allen and Mrs. Wilson have attempted to list every important reference, they make no claim to complete coverage of the published literature. The authors will be grateful to users of the bibliography who call attention to errors or omissions.

  13. QPSK regeneration without active phase-locking

    DEFF Research Database (Denmark)

    Kjøller, Niels-Kristian; Da Ros, Francesco; Røge, Kasper Meldgaard

    2016-01-01

    QPSK regeneration without active phase stabilization is investigated in numerical simulations. We propose an improved scheme for phase-locking free QPSK regeneration showing significant improvements in the error vector magnitude of the signal.......QPSK regeneration without active phase stabilization is investigated in numerical simulations. We propose an improved scheme for phase-locking free QPSK regeneration showing significant improvements in the error vector magnitude of the signal....

  14. Common Avian Infection Plagued the Tyrant Dinosaurs

    Science.gov (United States)

    Wolff, Ewan D. S.; Salisbury, Steven W.; Horner, John R.; Varricchio, David J.

    2009-01-01

    Background Tyrannosaurus rex and other tyrannosaurid fossils often display multiple, smooth-edged full-thickness erosive lesions on the mandible, either unilaterally or bilaterally. The cause of these lesions in the Tyrannosaurus rex specimen FMNH PR2081 (known informally by the name ‘Sue’) has previously been attributed to actinomycosis, a bacterial bone infection, or bite wounds from other tyrannosaurids. Methodology/Principal Findings We conducted an extensive survey of tyrannosaurid specimens and identified ten individuals with full-thickness erosive lesions. These lesions were described, measured and photographed for comparison with one another. We also conducted an extensive survey of related archosaurs for similar lesions. We show here that these lesions are consistent with those caused by an avian parasitic infection called trichomonosis, which causes similar abnormalities on the mandible of modern birds, in particular raptors. Conclusions/Significance This finding represents the first evidence for the ancient evolutionary origin of an avian transmissible disease in non-avian theropod dinosaurs. It also provides a valuable insight into the palaeobiology of these now extinct animals. Based on the frequency with which these lesions occur, we hypothesize that tyrannosaurids were commonly infected by a Trichomonas gallinae-like protozoan. For tyrannosaurid populations, the only non-avian dinosaur group that show trichomonosis-type lesions, it is likely that the disease became endemic and spread as a result of antagonistic intraspecific behavior, consumption of prey infected by a Trichomonas gallinae-like protozoan and possibly even cannibalism. The severity of trichomonosis-related lesions in specimens such as Tyrannosaurus rex FMNH PR2081 and Tyrannosaurus rex MOR 980, strongly suggests that these animals died as a direct result of this disease, mostly likely through starvation. PMID:19789646

  15. Avian influenza in birds and mammals.

    Science.gov (United States)

    Cardona, Carol J; Xing, Zheng; Sandrock, Christian E; Davis, Cristina E

    2009-07-01

    The disease syndromes caused by avian influenza viruses are highly variable depending on the host species infected, its susceptibility and response to infection and the virulence of the infecting viral strain. Although avian influenza viruses have a broad host range in general, it is rare for an individual strain or subtype to infect more than one species. The H5N1 highly pathogenic avian influenza virus (HPAIV) lineages of viruses that descended from A/goose/Guandong/96 (H5N1 HPAIV) are unusual in the diversity of species they have infected worldwide. Although the species affected by H5N1 HPAI in the field and those that have been experimentally studied are diverse, their associated disease syndromes are remarkably similar across species. In some species, multi-organ failure and death are rapid and no signs of the disease are observed. Most prominently in this category are chickens and other avian species of the order Galliformes. In other species, neurologic signs develop resulting in the death of the host. This is what has been reported in domestic cats (Carnivora), geese (Anseriformes), ratites (Struthioniformes), pigeons inoculated with high doses (Columbiformes) and ducks infected with H5N1 HPAIV isolated since 2002 (Anseriformes). In some other species, the disease is more prolonged and although multi-organ failure and death are the eventual outcomes, the signs of disease are more extensive. Predominantly, these species include humans (Primates) and the laboratory models of human disease, the ferret (Carnivora), mouse (Rodentia) and cynamologous macaques (Primates). Finally, some species are more resistant to infection with H5N1 HPAIV and show few or no signs of disease. These species include pigeons in some studies (Columbiformes), ducks inoculated with pre-2002 isolates (Anseriformes), and pigs (Artiodactyla).

  16. Common avian infection plagued the tyrant dinosaurs.

    Directory of Open Access Journals (Sweden)

    Ewan D S Wolff

    Full Text Available BACKGROUND: Tyrannosaurus rex and other tyrannosaurid fossils often display multiple, smooth-edged full-thickness erosive lesions on the mandible, either unilaterally or bilaterally. The cause of these lesions in the Tyrannosaurus rex specimen FMNH PR2081 (known informally by the name 'Sue' has previously been attributed to actinomycosis, a bacterial bone infection, or bite wounds from other tyrannosaurids. METHODOLOGY/PRINCIPAL FINDINGS: We conducted an extensive survey of tyrannosaurid specimens and identified ten individuals with full-thickness erosive lesions. These lesions were described, measured and photographed for comparison with one another. We also conducted an extensive survey of related archosaurs for similar lesions. We show here that these lesions are consistent with those caused by an avian parasitic infection called trichomonosis, which causes similar abnormalities on the mandible of modern birds, in particular raptors. CONCLUSIONS/SIGNIFICANCE: This finding represents the first evidence for the ancient evolutionary origin of an avian transmissible disease in non-avian theropod dinosaurs. It also provides a valuable insight into the palaeobiology of these now extinct animals. Based on the frequency with which these lesions occur, we hypothesize that tyrannosaurids were commonly infected by a Trichomonas gallinae-like protozoan. For tyrannosaurid populations, the only non-avian dinosaur group that show trichomonosis-type lesions, it is likely that the disease became endemic and spread as a result of antagonistic intraspecific behavior, consumption of prey infected by a Trichomonas gallinae-like protozoan and possibly even cannibalism. The severity of trichomonosis-related lesions in specimens such as Tyrannosaurus rex FMNH PR2081 and Tyrannosaurus rex MOR 980, strongly suggests that these animals died as a direct result of this disease, mostly likely through starvation.

  17. Expression of tumor necrosis factor-α and interleukin-1β genes in the cochlea and inferior colliculus in salicylate-induced tinnitus.

    Science.gov (United States)

    Hwang, Juen-Haur; Chen, Jin-Cherng; Yang, Shan-Ying; Wang, Ming-Fu; Chan, Yin-Ching

    2011-04-09

    Changes in the gene expressions for tumor necrosis factor-α (TNF-α) and/or interleukin-1β (IL-1β) during tinnitus have not been previously reported. We evaluated tinnitus and mRNA expression levels of TNF-α, IL-1β, and N-methyl D-aspartate receptor subunit 2B (NR2B) genes in cochlea and inferior colliculus (IC) of mice after intraperitoneal injections of salicylate. Forty-eight 3-month-old male SAMP8 mice were randomly and equally divided into two groups: salicylate-treated and saline-treated. All mice were trained to perform an active avoidance task for 5 days. Once conditioned, an active avoidance task was performed 2 hours after daily intraperitoneal injections of saline, either alone or containing 300 mg/kg sodium salicylate. Total numbers of times (tinnitus score) the mice climbed during the inter-trial silent period for 10 trials were recorded daily for 4 days (days 7 to 10), and then mice were euthanized for determination of mRNA expression levels of TNF-α, IL-1β, and NR2B genes in cochlea and IC at day 10. Tinnitus scores increased in response to daily salicylate treatments. The mRNA expression levels of TNF-α increased significantly for the salicylate-treated group compared to the control group in both cochlea (1.89 ± 0.22 vs. 0.87 ± 0.07, P salicylate group compared to the control group in both cochlea (3.50 ± 1.05 vs. 2.80 ± 0.28, p salicylate treatment resulting in tinnitus augments expression of the TNF-α and IL-1β genes in cochlea and IC of mice, and we suggest that these proinflammatory cytokines might lead to tinnitus directly or via modulating the NMDA receptor.

  18. Tracing the evolution of avian wing digits.

    Science.gov (United States)

    Xu, Xing; Mackem, Susan

    2013-06-17

    It is widely accepted that birds are a subgroup of dinosaurs, but there is an apparent conflict: modern birds have been thought to possess only the middle three fingers (digits II-III-IV) of an idealized five-digit tetrapod hand based on embryological data, but their Mesozoic tetanuran dinosaur ancestors are considered to have the first three digits (I-II-III) based on fossil evidence. How could such an evolutionary quirk arise? Various hypotheses have been proposed to resolve this paradox. Adding to the confusion, some recent developmental studies support a I-II-III designation for avian wing digits whereas some recent paleontological data are consistent with a II-III-IV identification of the Mesozoic tetanuran digits. A comprehensive analysis of both paleontological and developmental data suggests that the evolution of the avian wing digits may have been driven by homeotic transformations of digit identity, which are more likely to have occurred in a partial and piecemeal manner. Additionally, recent genetic studies in mouse models showing plausible mechanisms for central digit loss invite consideration of new alternative possibilities (I-II-IV or I-III-IV) for the homologies of avian wing digits. While much progress has been made, some advances point to the complexity of the problem and a final resolution to this ongoing debate demands additional work from both paleontological and developmental perspectives, which will surely yield new insights on mechanisms of evolutionary adaptation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Functionally heterogenous ryanodine receptors in avian cerebellum.

    Science.gov (United States)

    Sierralta, J; Fill, M; Suárez-Isla, B A

    1996-07-19

    The functional heterogeneity of the ryanodine receptor (RyR) channels in avian cerebellum was defined. Heavy endoplasmic reticulum microsomes had significant levels of ryanodine and inositol 1,4,5-trisphosphate binding. Scatchard analysis and kinetic studies indicated the existence of at least two distinct ryanodine binding sites. Ryanodine binding was calcium-dependent but was not significantly enhanced by caffeine. Incorporation of microsomes into planar lipid bilayers revealed ion channels with pharmacological features (calcium, magnesium, ATP, and caffeine sensitivity) similar to the RyR channels found in mammalian striated muscle. Despite a wide range of unitary conductances (220-500 picosiemens, symmetrical cesium methanesulfonate), ryanodine locked both channels into a characteristic slow gating subconductance state, positively identifying them as RyR channels. Two populations of avian RyR channels were functionally distinguished by single channel calcium sensitivity. One population was defined by a bell-shaped calcium sensitivity analogous to the skeletal muscle RyR isoform (type I). The calcium sensitivity of the second RyR population was sigmoidal and analogous to the cardiac muscle RyR isoform (type II). These data show that there are at least two functionally distinct RyR channel populations in avian cerebellum. This leads to the possibility that these functionally distinct RyR channels are involved in different intracellular calcium signaling pathways.

  20. Avian influenza overview September–November 2017

    DEFF Research Database (Denmark)

    Brown, Ian; Kuiken, Thijs; Mulatti, Paolo

    2017-01-01

    Between 1 September and 15 November 2017, 48 A(H5N8) highly pathogenic avian influenza (HPAI) outbreaks in poultry holdings and 9 H5 HPAI wild bird events were reported within Europe. A second epidemic HPAI A(H5N8) wave started in Italy on the third week of July and is still ongoing on 15November...... to focus in order to achieve the most effective testing of dead birds for detection of H5 HPAI viruses. Monitoring the avian influenza situation in other continents revealed the same risks as in the previous report (October 2016-August 2017): the recent human case of HPAI A(H5N6) in China underlines...... the continuing threat of this avian influenza virus to human health and possible introduction via migratory wild birds into Europe. Close monitoring is required of the situation in Africa with regards to HPAI of the subtypes A(H5N1) and A(H5N8), given the rapidity of the evolution and the uncertainty...

  1. Global phylogeographic limits of Hawaii's avian malaria

    Science.gov (United States)

    Beadell, J.S.; Ishtiaq, F.; Covas, R.; Melo, M.; Warren, B.H.; Atkinson, C.T.; Bensch, S.; Graves, G.R.; Jhala, Y.V.; Peirce, M.A.; Rahmani, A.R.; Fonseca, D.M.; Fleischer, R.C.

    2006-01-01

    The introduction of avian malaria (Plasmodium relictum) to Hawaii has provided a model system for studying the influence of exotic disease on naive host populations. Little is known, however, about the origin or the genetic variation of Hawaii's malaria and traditional classification methods have confounded attempts to place the parasite within a global ecological and evolutionary context. Using fragments of the parasite mitochondrial gene cytochrome b and the nuclear gene dihydrofolate reductase-thymidylate synthase obtained from a global survey of greater than 13 000 avian samples, we show that Hawaii's avian malaria, which can cause high mortality and is a major limiting factor for many species of native passerines, represents just one of the numerous lineages composing the morphological parasite species. The single parasite lineage detected in Hawaii exhibits a broad host distribution worldwide and is dominant on several other remote oceanic islands, including Bermuda and Moorea, French Polynesia. The rarity of this lineage in the continental New World and the restriction of closely related lineages to the Old World suggest limitations to the transmission of reproductively isolated parasite groups within the morphological species. ?? 2006 The Royal Society.

  2. Guide to Regeneration of Bottomland Hardwoods

    Science.gov (United States)

    Martha R. McKevlin

    1992-01-01

    This guide will help landowners, consulting foresters, and public service foresters regenerate bottomland hardwoods. It discusses (1) interpretation of site characteristics, (2) selection of species, and (3) selection of regeneration methods. A dichotomous key for selection of appropriate regeneration methods under various conditions is presented.

  3. All optical regeneration using semiconductor devices

    DEFF Research Database (Denmark)

    Mørk, Jesper; Öhman, Filip; Tromborg, Bjarne

    All-optical regeneration is a key functionality for implementing all-optical networks. We present a simple theory for the bit-error-rate in links employing all-optical regenerators, which elucidates the interplay between the noise and and nonlinearity of the regenerator. A novel device structure ...... is analyzed, emphasizing general aspects of active semiconductor waveguides....

  4. Semiconductor devices for all-optical regeneration

    DEFF Research Database (Denmark)

    Öhman, Filip; Bischoff, Svend; Tromborg, Bjarne

    2003-01-01

    We review different implementations of semiconductor devices for all-optical regeneration. A general model will be presented for all-optical regeneration in fiber links, taking into consideration the trade-off between non-linearity and noise. Furthermore we discuss a novel regenerator type, based...

  5. The blastema and epimorphic regeneration in mammals.

    Science.gov (United States)

    Seifert, Ashley W; Muneoka, Ken

    2018-01-15

    Studying regeneration in animals where and when it occurs is inherently interesting and a challenging research topic within developmental biology. Historically, vertebrate regeneration has been investigated in animals that display enhanced regenerative abilities and we have learned much from studying organ regeneration in amphibians and fish. From an applied perspective, while regeneration biologists will undoubtedly continue to study poikilothermic animals (i.e., amphibians and fish), studies focused on homeotherms (i.e., mammals and birds) are also necessary to advance regeneration biology. Emerging mammalian models of epimorphic regeneration are poised to help link regenerative biology and regenerative medicine. The regenerating rodent digit tip, which parallels human fingertip regeneration, and the regeneration of large circular defects through the ear pinna in spiny mice and rabbits, provide tractable, experimental systems where complex tissue structures are regrown through blastema formation and morphogenesis. Using these models as examples, we detail similarities and differences between the mammalian blastema and its classical counterpart to arrive at a broad working definition of a vertebrate regeneration blastema. This comparison leads us to conclude that regenerative failure is not related to the availability of regeneration-competent progenitor cells, but is most likely a function of the cellular response to the microenvironment that forms following traumatic injury. Recent studies demonstrating that targeted modification of this microenvironment can restrict or enhance regenerative capabilities in mammals helps provide a roadmap for eventually pushing the limits of human regeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. MECHANICAL REGENERATION OF SAND WASTE

    Directory of Open Access Journals (Sweden)

    D. I. Gnir

    2005-01-01

    Full Text Available The experimental activation of the sand regenerator of the firm SINTO is carried out at ОАО “MZOO". It is shown that sand grains are cleared from films of binding agents, that allows to use the treated sand for preparation of agglutinant and core sands.

  7. Basilar membrane and reticular lamina motion in a multi-scale finite element model of the mouse cochlea

    Science.gov (United States)

    Soons, Joris; Dirckx, Joris; Steele, Charles; Puria, Sunil

    2015-12-01

    A multi-scale finite element (FE) model of the mouse cochlea, based on its anatomy and material properties is presented. The important feature in the model is a lattice of 400 Y-shaped structures in the longitudinal direction, each formed by Deiters cells, phalangeal processes and outer hair cells (OHC). OHC somatic motility is modeled by an expansion force proportional to the shear on the stereocilia, which in turn is proportional to the pressure difference between the scala vestibule and scala tympani. Basilar membrane (BM) and reticular lamina (RL) velocity compare qualitatively very well with recent in vivo measurements in guinea pig [2]. Compared to the BM, the RL is shown to have higher amplification and a shift to higher frequencies. This comes naturally from the realistic Y-shaped cell organization without tectorial membrane tuning.

  8. Periodontal regeneration around natural teeth.

    Science.gov (United States)

    Garrett, S

    1996-11-01

    1. Evidence is conclusive (Table 2) that periodontal regeneration in humans is possible following the use of bone grafts, guided tissue regeneration procedures, both without and in combination with bone grafts, and root demineralization procedures. 2. Clinically guided tissue regeneration procedures have demonstrated significant positive clinical change beyond that achieved with debridement alone in treating mandibular and maxillary (buccal only) Class II furcations. Similar data exist for intraosseous defects. Evidence suggests that the use of bone grafts or GTR procedures produce equal clinical benefit in treating intraosseous defects. Further research is necessary to evaluate GTR procedures compared to, or combined with, bone grafts in treating intraosseous defects. 3. Although there are some data suggesting hopeful results in Class II furcations, the clinical advantage of procedures combining present regenerative techniques remains to be demonstrated. Additional randomized controlled trials with sufficient power are needed to demonstrate the potential usefulness of these techniques. 4. Outcomes following regenerative attempts remain somewhat variable with differences in results between studies and individual subjects. Some of this variability is likely patient related in terms of compliance with plaque control and maintenance procedures, as well as personal habits; e.g., smoking. Variations in the defects selected for study may also affect predictability of outcomes along with other factors. 5. There is evidence to suggest that present regenerative techniques lead to significant amounts of regeneration at localized sites on specific teeth. However, if complete regeneration is to become a reality, additional stimuli to enhance the regenerative process are likely needed. Perhaps this will be accomplished in the future, with combined procedures that include appropriate polypeptide growth factors or tissue factors to provide additional stimulus.

  9. Role of Neuropilin-1/Semaphorin-3A signaling in the functional and morphological integrity of the cochlea.

    Directory of Open Access Journals (Sweden)

    Pezhman Salehi

    2017-10-01

    Full Text Available Neuropilin-1 (Nrp1 encodes the transmembrane cellular receptor neuropilin-1, which is associated with cardiovascular and neuronal development and was within the peak SNP interval on chromosome 8 in our prior GWAS study on age-related hearing loss (ARHL in mice. In this study, we generated and characterized an inner ear-specific Nrp1 conditional knockout (CKO mouse line because Nrp1 constitutive knockouts are embryonic lethal. In situ hybridization demonstrated weak Nrp1 mRNA expression late in embryonic cochlear development, but increased expression in early postnatal stages when cochlear hair cell innervation patterns have been shown to mature. At postnatal day 5, Nrp1 CKO mice showed disorganized outer spiral bundles and enlarged microvessels of the stria vascularis (SV but normal spiral ganglion cell (SGN density and presynaptic ribbon body counts; however, we observed enlarged SV microvessels, reduced SGN density, and a reduction of presynaptic ribbons in the outer hair cell region of 4-month-old Nrp1 CKO mice. In addition, we demonstrated elevated hearing thresholds of the 2-month-old and 4-month-old Nrp1 CKO mice at frequencies ranging from 4 to 32kHz when compared to 2-month-old mice. These data suggest that conditional loss of Nrp1 in the inner ear leads to progressive hearing loss in mice. We also demonstrated that mice with a truncated variant of Nrp1 show cochlear axon guidance defects and that exogenous semaphorin-3A, a known neuropilin-1 receptor agonist, repels SGN axons in vitro. These data suggest that Neuropilin-1/Semaphorin-3A signaling may also serve a role in neuronal pathfinding in the developing cochlea. In summary, our results here support a model whereby Neuropilin-1/Semaphorin-3A signaling is critical for the functional and morphological integrity of the cochlea and that Nrp1 may play a role in ARHL.

  10. The Rho GTPase Cdc42 regulates hair cell planar polarity and cellular patterning in the developing cochlea

    Directory of Open Access Journals (Sweden)

    Anna Kirjavainen

    2015-03-01

    Full Text Available Hair cells of the organ of Corti (OC of the cochlea exhibit distinct planar polarity, both at the tissue and cellular level. Planar polarity at tissue level is manifested as uniform orientation of the hair cell stereociliary bundles. Hair cell intrinsic polarity is defined as structural hair bundle asymmetry; positioning of the kinocilium/basal body complex at the vertex of the V-shaped bundle. Consistent with strong apical polarity, the hair cell apex displays prominent actin and microtubule cytoskeletons. The Rho GTPase Cdc42 regulates cytoskeletal dynamics and polarization of various cell types, and, thus, serves as a candidate regulator of hair cell polarity. We have here induced Cdc42 inactivation in the late-embryonic OC. We show the role of Cdc42 in the establishment of planar polarity of hair cells and in cellular patterning. Abnormal planar polarity was displayed as disturbances in hair bundle orientation and morphology and in kinocilium/basal body positioning. These defects were accompanied by a disorganized cell-surface microtubule network. Atypical protein kinase C (aPKC, a putative Cdc42 effector, colocalized with Cdc42 at the hair cell apex, and aPKC expression was altered upon Cdc42 depletion. Our data suggest that Cdc42 together with aPKC is part of the machinery establishing hair cell planar polarity and that Cdc42 acts on polarity through the cell-surface microtubule network. The data also suggest that defects in apical polarization are influenced by disturbed cellular patterning in the OC. In addition, our data demonstrates that Cdc42 is required for stereociliogenesis in the immature cochlea.

  11. Characterisation and Identification of Avian Influenza Virus (AI

    Directory of Open Access Journals (Sweden)

    Dyah Ayu Hewajuli

    2008-06-01

    Full Text Available Avian Influenza is caused by Influenza A virus which is a member of Orthomyxoviridae family. Influenza A virus is enveloped single stranded RNA with eight-segmented, negative polarity and filament or oval form, 50 – 120 by 200 – 300 nm diameters. Influenza A viruses have been found to infect birds, human, pig, horse and sometimes in the other mammalian such as seal and whale. The viruses are divided into different subtypes based on the antigenic protein which covers the virus surface i.e. Haemaglutinin (HA and Neuraminidase (NA. In addition, the nomenclature of subtype virus is based on HA and NA i.e HxNx, for example H5N1, H9N2 and the others. According to pathogenic, it could be divided into two distinct groups, they are Highly Pathogenic Avian Influenza (HPAI and Low Pathogenic Avian Influenza (LPAI. The Avian Influenza viruses have been continuously occurred and spread out in some continents such us America, Europe, Africa and Asian countries. The outbreak of Avian Influenza caused high mortality on birds and it has been reported that in human case Avian Influenza subtype H5N1 virus has caused several deaths. To anticipate this condition, an effort to prevent the transmission of Avian Influenza is needed. These strategic attempts include biosecurity, depopulation, vaccination, control of virus movement, monitoring and evaluation. Laboratory diagnostic plays an important role for successful prevention, control and eradication programs of Avian Influenza. Recently, there are two diagnostic methods for Avian Influenza. They are conventional (virological diagnosis and molecular methods. The conventional method is usually used for initial diagnostic of Avian Influenza. The conventional method takes more time and more costly, whereas the molecular method is more effective than conventional method. Based on the available diagnostic technique, basically diagnostic of Avian Influenza is done by serology test, isolation and identification as well

  12. Optical Regeneration and Noise in Semiconductor Devices

    DEFF Research Database (Denmark)

    Öhman, Filip

    2005-01-01

    In this report all-optical 2R-regeneration in optical communication systems is investigated. A simple regenerator device based on concatenated semiconductor optical amplifiers (SOAs) and electro absorbers (EAs) is introduced and examined. Experiments show that the monolithic SOA-EA 2R-regenerator......In this report all-optical 2R-regeneration in optical communication systems is investigated. A simple regenerator device based on concatenated semiconductor optical amplifiers (SOAs) and electro absorbers (EAs) is introduced and examined. Experiments show that the monolithic SOA-EA 2R...

  13. Nerves Regulate Cardiomyocyte Proliferation and Heart Regeneration.

    Science.gov (United States)

    Mahmoud, Ahmed I; O'Meara, Caitlin C; Gemberling, Matthew; Zhao, Long; Bryant, Donald M; Zheng, Ruimao; Gannon, Joseph B; Cai, Lei; Choi, Wen-Yee; Egnaczyk, Gregory F; Burns, Caroline E; Burns, C Geoffrey; MacRae, Calum A; Poss, Kenneth D; Lee, Richard T

    2015-08-24

    Some organisms, such as adult zebrafish and newborn mice, have the capacity to regenerate heart tissue following injury. Unraveling the mechanisms of heart regeneration is fundamental to understanding why regeneration fails in adult humans. Numerous studies have revealed that nerves are crucial for organ regeneration, thus we aimed to determine whether nerves guide heart regeneration. Here, we show using transgenic zebrafish that inhibition of cardiac innervation leads to reduction of myocyte proliferation following injury. Specifically, pharmacological inhibition of cholinergic nerve function reduces cardiomyocyte proliferation in the injured hearts of both zebrafish and neonatal mice. Direct mechanical denervation impairs heart regeneration in neonatal mice, which was rescued by the administration of neuregulin 1 (NRG1) and nerve growth factor (NGF) recombinant proteins. Transcriptional analysis of mechanically denervated hearts revealed a blunted inflammatory and immune response following injury. These findings demonstrate that nerve function is required for both zebrafish and mouse heart regeneration. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. 9 CFR 113.326 - Avian Pox Vaccine.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Avian Pox Vaccine. 113.326 Section 113... Vaccines § 113.326 Avian Pox Vaccine. Fowl Pox Vaccine and Pigeon Pox Vaccine shall be prepared from virus... established as follows: (1) Fowl pox susceptible birds all of the same age and from the same source, shall be...

  15. Avian influenza, Newcastle and Gumboro disease antibodies and ...

    African Journals Online (AJOL)

    Studies on avian influenza and Newcastle disease focus on waterfowls, considered natural reservoirs of these viruses. This study surveyed avian influenza (AI), Gumboro and Newcastle disease antibodies and antigens in birds in live wild bird markets (LWBMs), live poultry markets (LPMs) and free flying in Kaduna State ...

  16. Flock-based surveillance for lowpathogenic avian influenza virus in ...

    African Journals Online (AJOL)

    Flock-based surveillance for lowpathogenic avian influenza virus in commercial breeders and layers, southwest Nigeria. ... African Journal of Infectious Diseases ... Background: Flock surveillance systems for avian influenza (AI) virus play a critical role in countries where vaccination is not practiced so as to establish the ...

  17. Molecular cloning and functional characterization of avian interleukin-19

    Science.gov (United States)

    The present study describes the cloning and functional characterization of avian interleukin (IL)-19, a cytokine that, in mammals, alters the balance of Th1 and Th2 cells in favor of the Th2 phenotype. The full-length avian IL-19 gene, located on chromosome 26, was amplified from LPS-stimulated chi...

  18. 9 CFR 113.208 - Avian Encephalomyelitis Vaccine, Killed Virus.

    Science.gov (United States)

    2010-01-01

    ..., Killed Virus. 113.208 Section 113.208 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.208 Avian Encephalomyelitis Vaccine, Killed Virus. Avian...

  19. Avian research in the U.S. Forest Service

    Science.gov (United States)

    Beatrice Van Horne

    2005-01-01

    Avian research in the Federal Government is in a crisis. Yes, there is a strong interest in avian research, as evidenced by the size and level of interest in this conference. But political parties increasingly see wildlife research as expendable. At the same time, the reaction to environment-friendly legislation of the 1970s and 1980s has been strong from both sides....

  20. Avian fossils from the Early Miocene Moghra Formation of Egypt ...

    African Journals Online (AJOL)

    Avian remains from the Early Miocene (~17 Ma) Moghra Formation of Egypt include new records of 'waterbirds' (storks, herons, pelicans and allies) and a ratite. Only a single avian fossil has been previously reported from Wadi Moghra and, thus, additional knowledge of the avifauna complements previously documented ...

  1. Genetic differences between avian and human isolates of Candida dubliniensis.

    LENUS (Irish Health Repository)

    McManus, Brenda A

    2009-09-01

    When Candida dubliniensis isolates obtained from seabird excrement and from humans in Ireland were compared by using multilocus sequence typing, 13 of 14 avian isolates were genetically distinct from human isolates. The remaining avian isolate was indistinguishable from a human isolate, suggesting that transmission may occur between humans and birds.

  2. Socioeconomic Impacts of Avian Influenza on Small and Backyard ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    This grant will allow APAIR to assess the socioeconomic impact of avian ... control measure to mitigate the negative effects of avian influenza and its control on ... New website will help record vital life events to improve access to services for all.

  3. Detecting emerging transmissibility of avian influenza virus in human households

    NARCIS (Netherlands)

    Boven, M. van; Koopmans, M.; Du Ry van Beest Holle, M.; Meijer, Adam; Klinkenberg, D.; Donnelly, C.A.; Heesterbeek, J.A.P.

    Accumulating infections of highly pathogenic H5N1 avian influenza in humans underlines the need to track the ability of these viruses to spread among humans. A human-transmissible avian influenza virus is expected to cause clusters of infections in humans living in close contact. Therefore,

  4. Detecting emerging transmissibility of avian influenza virus in human households

    NARCIS (Netherlands)

    Boven, van R.M.; Koopmans, M.; Du Ry Beest Holle, van M.; Meijer, A.; Klinkenberg, D.; Donnelly, C.; Heesterbeek, J.A.P.

    2007-01-01

    Accumulating infections of highly pathogenic H5N1 avian influenza in humans underlines the need to track the ability of these viruses to spread among humans. A human-transmissible avian influenza virus is expected to cause clusters of infections in humans living in close contact. Therefore,

  5. Ontogeny of avian thermoregulation from a neural point of view

    NARCIS (Netherlands)

    Baarendse, P.J.J.; Debonne, M.; Decuypere, M.P.; Kemp, B.; Brand, van den H.

    2007-01-01

    The ontogeny of thermoregulation differs among (avian) species, but in all species both neural and endocrinological processes are involved. In this review the neural processes in ontogeny of thermoregulation during the prenatal and early postnatal phase are discussed. Only in a few avian species

  6. Avian nestling predation by endangered Mount Graham red squirrel

    Science.gov (United States)

    Claire A. Zugmeyer; John L. Koprowski

    2007-01-01

    Studies using artificial nests or remote cameras have documented avian predation by red squirrels (Tamiasciurus hudsonicus). Although several direct observations of avian predation events are known in the northern range of the red squirrel distribution, no accounts have been reported in the southern portion. We observed predation upon a hermit thrush...

  7. Comparative genomics reveals insights into avian genome evolution and adaptation

    DEFF Research Database (Denmark)

    Zhang, Guojie; Li, Cai; Li, Qiye

    2014-01-01

    Birds are the most species-rich class of tetrapod vertebrates and have wide relevance across many research fields. We explored bird macroevolution using full genomes from 48 avian species representing all major extant clades. The avian genome is principally characterized by its constrained size, ...

  8. Avian influenza in shorebirds: experimental infection of ruddy turnstones (Arenaria interpres) with avian influenza virus

    Science.gov (United States)

    Hall, Jeffrey S.; Krauss, Scott; Franson, J. Christian; TeSlaa, Joshua L.; Nashold, Sean W.; Stallknecht, David E.; Webby, Richard J.; Webster, Robert G.

    2013-01-01

    Background: Low pathogenic avian influenza viruses (LPAIV) have been reported in shorebirds, especially at Delaware Bay, USA, during spring migration. However, data on patterns of virus excretion, minimal infectious doses, and clinical outcome are lacking. The ruddy turnstone (Arenaria interpres) is the shorebird species with the highest prevalence of influenza virus at Delaware Bay. Objectives: The primary objective of this study was to experimentally assess the patterns of influenza virus excretion, minimal infectious doses, and clinical outcome in ruddy turnstones. Methods: We experimentally challenged ruddy turnstones using a common LPAIV shorebird isolate, an LPAIV waterfowl isolate, or a highly pathogenic H5N1 avian influenza virus. Cloacal and oral swabs and sera were analyzed from each bird. Results: Most ruddy turnstones had pre-existing antibodies to avian influenza virus, and many were infected at the time of capture. The infectious doses for each challenge virus were similar (103·6–104·16 EID50), regardless of exposure history. All infected birds excreted similar amounts of virus and showed no clinical signs of disease or mortality. Influenza A-specific antibodies remained detectable for at least 2 months after inoculation. Conclusions: These results provide a reference for interpretation of surveillance data, modeling, and predicting the risks of avian influenza transmission and movement in these important hosts.

  9. assessment of the economic and social implications of the avian flu ...

    African Journals Online (AJOL)

    Admin

    2006-01-22

    Jan 22, 2006 ... KEYWORDS: Assessment, Economic, Social Implications, Avian Flu, Nigerian Poultry. INTRODUCTION. Avian flu is a highly infectious, contagious and zoonotic disease of man, poultry and other birds caused by the avian influenza type A virus, Emmanuel et.al. (2006). The avian influenza virus belongs to ...

  10. The public health impact of avian influenza viruses.

    Science.gov (United States)

    Katz, J M; Veguilla, V; Belser, J A; Maines, T R; Van Hoeven, N; Pappas, C; Hancock, K; Tumpey, T M

    2009-04-01

    Influenza viruses with novel hemagglutinin and 1 or more accompanying genes derived from avian influenza viruses sporadically emerge in humans and have the potential to result in a pandemic if the virus causes disease and spreads efficiently in a population that lacks immunity to the novel hemagglutinin. Since 1997, multiple avian influenza virus subtypes have been transmitted directly from domestic poultry to humans and have caused a spectrum of human disease, from asymptomatic to severe and fatal. To assess the pandemic risk that avian influenza viruses pose, we have used multiple strategies to better understand the capacity of avian viruses to infect, cause disease, and transmit among mammals, including humans. Seroepidemiologic studies that evaluate the frequency and risk of human infection with avian influenza viruses in populations with exposure to domestic or wild birds can provide a better understanding of the pandemic potential of avian influenza subtypes. Investigations conducted in Hong Kong following the first H5N1 outbreak in humans in 1997 determined that exposure to poultry in live bird markets was a key risk factor for human disease. Among poultry workers, butchering and exposure to sick poultry were risk factors for antibody to H5 virus, which provided evidence for infection. A second risk assessment tool, the ferret, can be used to evaluate the level of virulence and potential for host-to-host transmission of avian influenza viruses in this naturally susceptible host. Avian viruses isolated from humans exhibit a level of virulence and transmissibility in ferrets that generally reflects that seen in humans. The ferret model thus provides a means to monitor emerging avian influenza viruses for pandemic risk, as well as to evaluate laboratory-generated reassortants and mutants to better understand the molecular basis of influenza virus transmissibility. Taken together, such studies provide valuable information with which we can assess the public

  11. MHD (Magnetohydrodynamics) recovery and regeneration

    Energy Technology Data Exchange (ETDEWEB)

    McIlroy, R. A. [Babcock and Wilcox Co., Alliance, OH (United States). Research Center; Probert, P. B. [Babcock and Wilcox Co., Alliance, OH (United States). Research Center; Lahoda, E. J. [Westinghouse Electric Corp., Pittsburgh, PA (United States); Swift, W. M. [Argonne National Lab. (ANL), Argonne, IL (United States); Jackson, D. M. [Univ. of Tennessee Space Inst. (UTSI), Tullahoma, TN (United States); Prasad, J. [Univ. of Tennessee Space Inst. (UTSI), Tullahoma, TN (United States); Martin, J. [Hudson Engineering (United States); Rogers, C. [Hudson Engineering (United States); Ho, K. K. [Babcock and Wilcox Co., Alliance, OH (United States). Research Center; Senary, M. K. [Babcock and Wilcox Co., Alliance, OH (United States). Research Center; Lee, S. [Univ. of Akron, OH (United States)

    1988-10-01

    A two-phase program investigating MHD seed regeneration is described. In Phase I, bench scale experiments were carried out to demonstrate the technical feasibility of a proposed Seed Regeneration Process. The Phase I data has been used for the preliminary design of a Proof-of-Concept (POC) plant which will be built and tested in Phase II. The Phase I data will also be used to estimate the costs of a 300 Mw(t) demonstration plant for comparison with other processes. The Seed Regeneration Process consists of two major subprocesses; a Westinghouse Dry Reduction process and a modified Tampella (sulfur) Recovery process. The Westinghouse process reduces the recovered spent seed (i.e., potassium sulfate) to potassium polysulfide in a rotary kiln. The reduction product is dissolved in water to form green liquor, clarified to remove residual coal ash, and sent to the Tampella sulfur release system. The sulfur is released using carbon dioxide from flue gas in a two stage reaction. The sulfur is converted to elemental sulfur as a marketable by product. The potassium is crystallized from the green liquor and dried to the anhydrous form for return to the MHD unit.

  12. The threshold of a stochastic avian-human influenza epidemic model with psychological effect

    Science.gov (United States)

    Zhang, Fengrong; Zhang, Xinhong

    2018-02-01

    In this paper, a stochastic avian-human influenza epidemic model with psychological effect in human population and saturation effect within avian population is investigated. This model describes the transmission of avian influenza among avian population and human population in random environments. For stochastic avian-only system, persistence in the mean and extinction of the infected avian population are studied. For the avian-human influenza epidemic system, sufficient conditions for the existence of an ergodic stationary distribution are obtained. Furthermore, a threshold of this stochastic model which determines the outcome of the disease is obtained. Finally, numerical simulations are given to support the theoretical results.

  13. [Epidemiological perspectives on SARS and avian influenza].

    Science.gov (United States)

    del Rey Calero, Juan

    2004-01-01

    SARS is a respiratory infection caused by Coronavirus (Nidoviruses, RNA) from which 3 groups are known. Group 1 affects dogs, cats, pigs, and the human agent is 229 E. Group 2 affects bovines or rodents, and the human agent is OC43. And group 3 corresponds to the avian pathology.... The epidemics emerged on February 2003 in Guangdong, South China, due to consumption of exotic animals (Civeta, etc.), and it spread through interperson contagion to other regions in Asia, America and Europe. Incubation period is about 2-7 days. Transmission Of the virus is person-to person, but also by excretions and residual water. Basic reproductive rate is 2 to 4, and it is considered that 2.7 persons are infected from the initial case. In June 2003, SARS affected over 8,000 people and 774 were killed. Mortality approaches to 10%, and it is higher among older people rising up to 50% in those aged over 65 years. It is important to quickly establish action protocols regarding clinical, epidemiological and prevention aspects. Avian influenza is an infection caused by type A Influenza Orthomixovirus, in which migration birds and wild ducks are the main reservoir. Avian viruses correspond to H5, H7, H9. In 1997 it was observed that type AH5N1 jumped interspecies barrier and affected 18 humans, and 6 of them died. At the end of 2003 and in 2004 this type of poultry flu was described in Asia. FAO has emphasized that sacrifice of chicken in affected farms is the most effective measure to fight against the disease. It has also been established suppression of imports from these countries. There is no evidence on interperson contagion from chicken contagion, nor on food-borne contagion to humans.

  14. Cell migration during heart regeneration in zebrafish.

    Science.gov (United States)

    Tahara, Naoyuki; Brush, Michael; Kawakami, Yasuhiko

    2016-07-01

    Zebrafish possess the remarkable ability to regenerate injured hearts as adults, which contrasts the very limited ability in mammals. Although very limited, mammalian hearts do in fact have measurable levels of cardiomyocyte regeneration. Therefore, elucidating mechanisms of zebrafish heart regeneration would provide information of naturally occurring regeneration to potentially apply to mammalian studies, in addition to addressing this biologically interesting phenomenon in itself. Studies over the past 13 years have identified processes and mechanisms of heart regeneration in zebrafish. After heart injury, pre-existing cardiomyocytes dedifferentiate, enter the cell cycle, and repair the injured myocardium. This process requires interaction with epicardial cells, endocardial cells, and vascular endothelial cells. Epicardial cells envelope the heart, while endocardial cells make up the inner lining of the heart. They provide paracrine signals to cardiomyocytes to regenerate the injured myocardium, which is vascularized during heart regeneration. In addition, accumulating results suggest that local migration of these major cardiac cell types have roles in heart regeneration. In this review, we summarize the characteristics of various heart injury methods used in the research community and regeneration of the major cardiac cell types. Then, we discuss local migration of these cardiac cell types and immune cells during heart regeneration. Developmental Dynamics 245:774-787, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  15. USGS highly pathogenic avian influenza research strategy

    Science.gov (United States)

    Harris, M. Camille; Miles, A. Keith; Pearce, John M.; Prosser, Diann J.; Sleeman, Jonathan M.; Whalen, Mary E.

    2015-09-09

    Avian influenza viruses are naturally occurring in wild birds such as ducks, geese, swans, and gulls. These viruses generally do not cause illness in wild birds, however, when spread to poultry they can be highly pathogenic and cause illness and death in backyard and commercial farms. Outbreaks may cause devastating agricultural economic losses and some viral strains have the potential to infect people directly. Furthermore, the combination of avian influenza viruses with mammalian viruses can result in strains with the ability to transmit from person to person, possibly leading to viruses with pandemic potential. All known pandemic influenza viruses have had some genetic material of avian origin. Since 1996, a strain of highly pathogenic avian influenza (HPAI) virus, H5N1, has caused infection in wild birds, losses to poultry farms in Eurasia and North Africa, and led to the deaths of several hundred people. Spread of the H5N1 virus and other influenza strains from China was likely facilitated by migratory birds. In December 2014, HPAI was detected in poultry in Canada and migratory birds in the United States. Since then, HPAI viruses have spread to large parts of the United States and will likely continue to spread through migratory bird flyways and other mechanisms throughout North America. In the United States, HPAI viruses have severely affected the poultry industry with millions of domestic birds dead or culled. These strains of HPAI are not known to cause disease in humans; however, the Centers for Disease Control and Prevention (CDC) advise caution when in close contact with infected birds. Experts agree that HPAI strains currently circulating in wild birds of North America will likely persist for the next few years. This unprecedented situation presents risks to the poultry industry, natural resource management, and potentially human health. Scientific knowledge and decision support tools are urgently needed to understand factors affecting the persistence

  16. Absolute measurement of subnanometer scale vibration of cochlear partition of an excised guinea pig cochlea using spectral-domain phase-sensitive optical coherence tomography

    Science.gov (United States)

    Subhash, Hrebesh M.; Choudhury, Niloy; Jacques, Steven L.; Wang, Ruikang K.; Chen, Fangyi; Zha, Dingjun; Nuttall, Alfred L.

    2012-01-01

    Direct measurement of absolute vibration parameters from different locations within the mammalian organ of Corti is crucial for understanding the hearing mechanics such as how sound propagates through the cochlea and how sound stimulates the vibration of various structures of the cochlea, namely, basilar membrane (BM), recticular lamina, outer hair cells and tectorial membrane (TM). In this study we demonstrate the feasibility a modified phase-sensitive spectral domain optical coherence tomography system to provide subnanometer scale vibration information from multiple angles within the imaging beam. The system has the potential to provide depth resolved absolute vibration measurement of tissue microstructures from each of the delay-encoded vibration images with a noise floor of ~0.3nm at 200Hz.

  17. Dendrite Injury Triggers DLK-Independent Regeneration

    Directory of Open Access Journals (Sweden)

    Michelle C. Stone

    2014-01-01

    Full Text Available Axon injury triggers regeneration through activation of a conserved kinase cascade, which includes the dual leucine zipper kinase (DLK. Although dendrites are damaged during stroke, traumatic brain injury, and seizure, it is not known whether mature neurons monitor dendrite injury and initiate regeneration. We probed the response to dendrite damage using model Drosophila neurons. Two larval neuron types regrew dendrites in distinct ways after all dendrites were removed. Dendrite regeneration was also triggered by injury in adults. Next, we tested whether dendrite injury was initiated with the same machinery as axon injury. Surprisingly, DLK, JNK, and fos were dispensable for dendrite regeneration. Moreover, this MAP kinase pathway was not activated by injury to dendrites. Thus, neurons respond to dendrite damage and initiate regeneration without using the conserved DLK cascade that triggers axon regeneration.

  18. A duetting perspective on avian song learning.

    Science.gov (United States)

    Rivera-Cáceres, Karla D; Templeton, Christopher N

    2017-12-25

    Avian song learning has a rich history of study and has become the preeminent system for understanding the ontogeny of vocal communication in animals. Song learning in birds has many parallels with human language learning, ranging from the neural mechanisms involved to the importance of social factors in shaping signal acquisition. While much has been learned about the process of song learning, virtually all of the research done to date has focused on temperate species, where often only one sex (the male) sings. Duetting species, in which both males and females learn to sing and learn to combine their songs into temporally coordinated joint displays, could provide many insights into the processes by which vocal learning takes place. Here we highlight three key features of song learning-neuroendocrine control mechanisms, timing and life history stages of song acquisition, and the role of social factors in song selection and use-that have been elucidated from species where only males sing, and compare these with duetting species. We summarize what is known about song learning in duetting species and then provide several suggestions for fruitful directions for future research. We suggest that focusing research efforts on duetting species could significantly advance our understanding of vocal learning in birds and further cement the importance of avian species as models for understanding human conversations and the processes of vocal learning more broadly. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Developmental studies of avian brain organization.

    Science.gov (United States)

    Puelles, Luis

    2018-01-01

    Avian brain organization or brain Bauplan is identical with that of vertebrates in general. This essay visits avian studies that contained advances or discussions about brain organization, trying to explain critically what they contributed. In order to start from a specific background, the new prevailing paradigm as regards brain organization, the prosomeric model, is presented first. Next a brief historic survey is made of how ideas on this topic evolved from the start of modern neuromorphology at the end of the 19th century. Longitudinal zonal organization with or without transverse segmentation (neuromeres) was the first overall concept applied to the brain. The idea of neuromeric structure later decayed in favour of a columnar model. This emphasized functional correlations rather than causal developmental content, assimilating forebrain functions to hindbrain ones. Though it became prevalent in the post-world-war period of neuroscience, in the last decades of the 20th century advances in molecular biology allowed developmental genes to be mapped, and it became evident that gene expression patterns support the old neuromeric model rather than the columnar one. This was also corroborated by modern experimental approaches (fate-mapping and analysis of patterning).

  20. Avian colibacillosis: still many black holes.

    Science.gov (United States)

    Guabiraba, Rodrigo; Schouler, Catherine

    2015-08-01

    Avian pathogenic Escherichia coli (APEC) strains cause severe respiratory and systemic diseases, threatening food security and avian welfare worldwide. Intensification of poultry production and the quick expansion of free-range production systems will increase the incidence of colibacillosis through greater exposure of birds to pathogens and stress. Therapy is mainly based on antibiotherapy and current vaccines have poor efficacy. Serotyping remains the most frequently used diagnostic method, only allowing the identification of a limited number of APEC strains. Several studies have demonstrated that the most common virulence factors studied in APEC are all rarely present in the same isolate, showing that APEC strains constitute a heterogeneous group. Different isolates may harbor different associations of virulence factors, each one able to induce colibacillosis. Despite its economical relevance, pathogenesis of colibacillosis is poorly understood. Our knowledge on the host response to APEC is based on very descriptive studies, mostly restricted to bacteriological and histopathological analysis of infected organs such as lungs. Furthermore, only a small number of APEC isolates have been used in experimental studies. In the present review, we discuss current knowledge on APEC diversity and virulence, including host response to infection and the associated inflammatory response with a focus on pulmonary colibacillosis. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Bibliography of references to avian botulism: Update

    Science.gov (United States)

    Wilson, Sonoma S.; Locke, Louis N.

    1982-01-01

    This bibliography, first compiled in 1970 (Allen and Wilson 1977) and published in 1977 in response to many requests for information on avian botulism, has been updated to include the literature published through 1980.In general, only articles dealing primarily with the avian disease are included, as opposed to those concerned with the various aspects of the biology of Clostridium botulinum, either type C or E. A few exceptions, such as Bengtson's report of the first isolation and description of the type C organism, are included for their historical interest. Progress reports and other administrative documents not available for distribution on request are excluded, as are most textbook accounts, which are generally summaries of work published elsewhere.This bibliography was a cooperative effort by the National Wildlife Health Laboratory, U.S. Fish and Wildlife Service, and the U.S. National Park Service. The National Park Service provided partial funding for the work through Contract No. 89100-0491.Although the authors attempted to list every important reference, they make no claim to complete coverage of the published literature. The authors will be grateful to users of the bibliography who call attention to errors or omissions.Wayne I. Jensen (Retired)Milton Friend, Director, National Wildlife Health Laboratory

  2. Collapsing avian community on a Hawaiian island

    Science.gov (United States)

    Paxton, Eben H.; Camp, Richard J.; Gorresen, P. Marcos; Crampton, Lisa H.; Leonard, David L.; VanderWerf, Eric

    2016-01-01

    The viability of many species has been jeopardized by numerous negative factors over the centuries, but climate change is predicted to accelerate and increase the pressure of many of these threats, leading to extinctions. The Hawaiian honeycreepers, famous for their spectacular adaptive radiation, are predicted to experience negative responses to climate change, given their susceptibility to introduced disease, the strong linkage of disease distribution to climatic conditions, and their current distribution. We document the rapid collapse of the native avifauna on the island of Kaua‘i that corresponds to changes in climate and disease prevalence. Although multiple factors may be pressuring the community, we suggest that a tipping point has been crossed in which temperatures in forest habitats at high elevations have reached a threshold that facilitates the development of avian malaria and its vector throughout these species’ ranges. Continued incursion of invasive weeds and non-native avian competitors may be facilitated by climate change and could also contribute to declines. If current rates of decline continue, we predict multiple extinctions in the coming decades. Kaua‘i represents an early warning for the forest bird communities on the Maui and Hawai‘i islands, as well as other species around the world that are trapped within a climatic space that is rapidly disappearing.

  3. Gas exchange in avian embryos and hatchlings.

    Science.gov (United States)

    Mortola, Jacopo P

    2009-08-01

    The avian egg has been proven to be an excellent model for the study of the physical principles and the physiological characteristics of embryonic gas exchange. In recent years, it has become a model for the studies of the prenatal development of pulmonary ventilation, its chemical control and its interaction with extra-pulmonary gas exchange. Differently from mammals, in birds the initiation of pulmonary ventilation and the transition from diffusive to convective gas exchange are gradual and slow-occurring events amenable to detailed investigations. The absence of the placenta and of the mother permits the study of the mechanisms of embryonic adaptation to prenatal perturbations in a way that would be impossible with mammalian preparations. First, this review summarises the general aspects of the natural history of the avian egg that are pertinent to embryonic metabolism, growth and gas exchange and the characteristics of the structures participating in gas exchange. Then, the review focuses on the embryonic development of pulmonary ventilation, its regulation in relation to the embryo's environment and metabolic state, the effects that acute or sustained changes in embryonic temperature or oxygenation can have on growth, metabolism and ventilatory control.

  4. Avian influenza virus transmission to mammals.

    Science.gov (United States)

    Herfst, S; Imai, M; Kawaoka, Y; Fouchier, R A M

    2014-01-01

    Influenza A viruses cause yearly epidemics and occasional pandemics. In addition, zoonotic influenza A viruses sporadically infect humans and may cause severe respiratory disease and fatalities. Fortunately, most of these viruses do not have the ability to be efficiently spread among humans via aerosols or respiratory droplets (airborne transmission) and to subsequently cause a pandemic. However, adaptation of these zoonotic viruses to humans by mutation or reassortment with human influenza A viruses may result in airborne transmissible viruses with pandemic potential. Although our knowledge of factors that affect mammalian adaptation and transmissibility of influenza viruses is still limited, we are beginning to understand some of the biological traits that drive airborne transmission of influenza viruses among mammals. Increased understanding of the determinants and mechanisms of airborne transmission may aid in assessing the risks posed by avian influenza viruses to human health, and preparedness for such risks. This chapter summarizes recent discoveries on the genetic and phenotypic traits required for avian influenza viruses to become airborne transmissible between mammals.

  5. Simulation of mechano-electrical transduction in the cochlea considering basilar membrane vibration and the ionic current of the inner hair cells

    Science.gov (United States)

    Lee, Sinyoung; Koike, Takuji

    2018-05-01

    The inner hair cells (IHCs) in the cochlea transduce mechanical vibration of the basilar membrane (BM), caused by sound pressure, to electrical signals that are transported along the acoustic nerve to the brain. The mechanical vibration of the BM and the ionic behaviors of the IHCs have been investigated. However, consideration of the ionic behavior of the IHCs related to mechanical vibration is necessary to investigate the mechano-electrical transduction of the cochlea. In this study, a finite-element model of the BM, which takes into account the non-linear activities of the outer hair cells (OHCs), and an ionic current model of IHC were combined. The amplitudes and phases of the vibration at several points on the BM were obtained from the finite-element model by applying sound pressure. These values were fed into the ionic current model, and changes in membrane potential and calcium ion concentration of the IHCs were calculated. The membrane potential of the IHC at the maximum amplitude point (CF point) was higher than that at the non-CF points. The calcium ion concentration at the CF point was also higher than that at the non-CF points. These results suggest that the cochlea achieves its good frequency discrimination ability through mechano-electrical transduction.

  6. Irradiation inhibits the regeneration of aneurogenic limbs

    International Nuclear Information System (INIS)

    Wallace, H.; Maden, M.

    1976-01-01

    The developing arms of axolotl larvae from the 2-digit stage onward and the aneurogenic arms of surgically denervated larvae maintained in parabiosis are able to regenerate after amputation. Such regeneration is uniformly inhibited by local irradiation of the arm, whether innervated or not. This demonstration refutes a recent hypothesis that x-rays interfere with a special activity of nerves required for regeneration, and supports the earlier concept that x-rays act directly on those cells which must proliferate to form the regenerated tissues

  7. Early regulation of axolotl limb regeneration.

    Science.gov (United States)

    Makanae, Aki; Satoh, Akira

    2012-10-01

    Amphibian limb regeneration has been studied for a long time. In amphibian limb regeneration, an undifferentiated blastema is formed around the region damaged by amputation. The induction process of blastema formation has remained largely unknown because it is difficult to study the induction of limb regeneration. The recently developed accessory limb model (ALM) allows the investigation of limb induction and reveals early events of amphibian limb regeneration. The interaction between nerves and wound epidermis/epithelium is an important aspect of limb regeneration. During early limb regeneration, neurotrophic factors act on wound epithelium, leading to development of a functional epidermis/epithelium called the apical epithelial cap (AEC). AEC and nerves create a specific environment that inhibits wound healing and induces regeneration through blastema formation. It is suggested that FGF-signaling and MMP activities participate in creating a regenerative environment. To understand why urodele amphibians can create such a regenerative environment and humans cannot, it is necessary to identify the similarities and differences between regenerative and nonregenerative animals. Here we focus on ALM to consider limb regeneration from a new perspective and we also reported that focal adhesion kinase (FAK)-Src signaling controlled fibroblasts migration in axolotl limb regeneration. Copyright © 2012 Wiley Periodicals, Inc.

  8. Angiogenesis is inhibitory for mammalian digit regeneration

    Science.gov (United States)

    Yu, Ling; Yan, Mingquan; Simkin, Jennifer; Ketcham, Paulina D.; Leininger, Eric; Han, Manjong

    2014-01-01

    Abstract The regenerating mouse digit tip is a unique model for investigating blastema formation and epimorphic regeneration in mammals. The blastema is characteristically avascular and we previously reported that blastema expression of a known anti‐angiogenic factor gene, Pedf, correlated with a successful regenerative response (Yu, L., Han, M., Yan, M., Lee, E. C., Lee, J. & Muneoka, K. (2010). BMP signaling induces digit regeneration in neonatal mice. Development, 137, 551–559). Here we show that during regeneration Vegfa transcripts are not detected in the blastema but are expressed at the onset of differentiation. Treating the amputation wound with vascular endothelial growth factor enhances angiogenesis but inhibits regeneration. We next tested bone morphogenetic protein 9 (BMP9), another known mediator of angiogenesis, and found that BMP9 is also a potent inhibitor of digit tip regeneration. BMP9 induces Vegfa expression in the digit stump suggesting that regenerative failure is mediated by enhanced angiogenesis. Finally, we show that BMP9 inhibition of regeneration is completely rescued by treatment with pigment epithelium‐derived factor. These studies show that precocious angiogenesis is inhibitory for regeneration, and provide compelling evidence that the regulation of angiogenesis is a critical factor in designing therapies aimed at stimulating mammalian regeneration. PMID:27499862

  9. Replication of avian influenza A viruses in mammals.

    OpenAIRE

    Hinshaw, V S; Webster, R G; Easterday, B C; Bean, W J

    1981-01-01

    The recent appearance of an avian influenza A virus in seals suggests that viruses are transmitted from birds to mammals in nature. To examine this possibility, avian viruses of different antigenic subtypes were evaluated for their ability to replicate in three mammals-pigs, ferrets, and cats. In each of these mammals, avian strains replicated to high titers in the respiratory tract (10(5) to 10(7) 50% egg infective doses per ml of nasal wash), with peak titers at 2 to 4 days post-inoculation...

  10. Data base on avian mortality on man-made structures

    Energy Technology Data Exchange (ETDEWEB)

    Dailey, N. S.

    1978-01-01

    A computerized data base concerning avian mortality on man-made structures is available for searching at the Ecological Sciences Information Center of the Information Center Complex, Information Division, Oak Ridge National Laboratory. This data base, which contains entries from the available literature, provides information on avian mortality from either collision into or electrocution on man-made structures. Primary emphasis has been placed on avian collision with obstacles such as television and radio towers, airport ceilometers, transmission lines, and cooling towers. Other structures included in the studies are fences, glass walls and windows, lighthouses, telegraph and telephone wires, buildings, monuments, smokestacks, and water towers.

  11. Towards Regeneration of Articular Cartilage

    Science.gov (United States)

    Iwamoto, Masahiro; Ohta, Yoichi; Larmour, Colleen; Enomoto-Iwamoto, Motomi

    2014-01-01

    Articular cartilage is classified into permanent hyaline cartilage and has significant differences in structure, extracelluar matrix components, gene expression profile, and mechanical property from transient hyaline cartilage found in growth plate. In the process of synovial joint development, articular cartilage is originated from the interzone, developing at the edge of the cartilaginous anlagen, it establishes zonal structure over time and supports smooth movement of the synovial joint through life. The cascade actions of key regulators such as Wnts, GDF5, Erg, and PTHLH coordinate sequential steps of articular cartilage formation. Articular chondrocytes are restrictedly controlled not to differentiate into a hypertrophic stage by autocrine and paracrine factors and extracerllular matrix microenvironment, but retain potential to undergo hypertrophy. The basal calcified zone of articular cartilage is connected with subchondral bone, but not invaded by blood vessels nor replaced by bone, which is highly contrasted with the growth plate. Articular cartilage has limited regenerative capacity, but likely possesses and potentially uses intrinsic stem cell source in the superficial layer, Ranvier’s groove, the intra-articular tissues such as synovium and fat pad, and marrow below the subchondral bone. Considering the biological views on articular cartilage, several important points are raised for regeneration of articular cartilage. We should evaluate the nature of regenerated cartilage as permanent hyaline cartilage and not just hyaline cartilage. We should study how a hypertrophic phenotype of transplanted cells can be lastingly suppressed in regenerating tissue. Further, we should develop the methods and reagents to activate recruitment of intrinsic stem/progenitor cells into the damaged site. PMID:24078496

  12. The Amount of Regenerated Heat Inside the Regenerator of a Stirling Engine

    Directory of Open Access Journals (Sweden)

    J. Škorpík

    2008-01-01

    Full Text Available The paper deals with analytical computing of the regenerated heat inside the regenerator of a Stirling engine. The total sum of the regenerated heat is constructed as a function of the crank angle in the case of Schmidt’s idealization. 

  13. Purifying and regenerating hydrocarbon oils

    Energy Technology Data Exchange (ETDEWEB)

    1931-11-19

    Hydrocarbons are freed from sulfur-containing compounds, colloidal asphaltic bodies and unstable unsaturated substances by treatment with a small amount of dilute sulfuric acid and a salt of a trivalent cation, such as ferric chloride or sulfate. Hydrocarbons specified are petroleum, crude benzol, low temperature tars, shale oil or vapor-phase cracked spirit. Motor spirit or lubricating oil distillates are refined and finally distilled. The acid reagent may be regenerated by filtering through sand or asbestos. Used lubricating oils may be treated similarly and after removal of refining agent, the oil is heated with an adsorbent and decolorizing material and then filtered.

  14. Bone regeneration and stem cells

    Science.gov (United States)

    Arvidson, K; Abdallah, B M; Applegate, L A; Baldini, N; Cenni, E; Gomez-Barrena, E; Granchi, D; Kassem, M; Konttinen, Y T; Mustafa, K; Pioletti, D P; Sillat, T; Finne-Wistrand, A

    2011-01-01

    Abstract This invited review covers research areas of central importance for orthopaedic and maxillofacial bone tissue repair, including normal fracture healing and healing problems, biomaterial scaffolds for tissue engineering, mesenchymal and foetal stem cells, effects of sex steroids on mesenchymal stem cells, use of platelet-rich plasma for tissue repair, osteogenesis and its molecular markers. A variety of cells in addition to stem cells, as well as advances in materials science to meet specific requirements for bone and soft tissue regeneration by addition of bioactive molecules, are discussed. PMID:21129153

  15. Bone regeneration and stem cells

    DEFF Research Database (Denmark)

    Arvidson, K; Abdallah, B M; Applegate, L A

    2011-01-01

    cells, use of platelet rich plasma for tissue repair, osteogenesis and its molecular markers. A variety of cells in addition to stem cells, as well as advances in materials science to meet specific requirements for bone and soft tissue regeneration by addition of bioactive molecules, are discussed.......This invited review covers research areas of central importance for orthopedic and maxillofacial bone tissue repair, including normal fracture healing and healing problems, biomaterial scaffolds for tissue engineering, mesenchymal and fetal stem cells, effects of sex steroids on mesenchymal stem...

  16. Effect of low-level laser treatment on cochlea hair-cell recovery after ototoxic hearing loss

    Science.gov (United States)

    Rhee, Chung-Ku; He, Peijie; Jung, Jae Yun; Ahn, Jin-Chul; Chung, Phil-Sang; Lee, Min Young; Suh, Myung-Whan

    2013-12-01

    The primary cause of hearing loss includes damage to cochlear hair cells. Low-level laser therapy (LLLT) has become a popular treatment for damaged nervous systems. Based on the idea that cochlea hair cells and neural cells are from same developmental origin, the effect of LLLT on hearing loss in animal models is evaluated. Hearing loss animal models were established, and the animals were irradiated by 830-nm diode laser once a day for 10 days. Power density of the laser treatment was 900 mW/cm2, and the fluence was 162 to 194 J. The tympanic membrane was evaluated after LLLT. Thresholds of auditory brainstem responses were evaluated before treatment, after gentamicin, and after 10 days of LLLT. Quantitative scanning electron microscopic (SEM) observations were done by counting remaining hair cells. Tympanic membranes were intact at the end of the experiment. No adverse tissue reaction was found. On SEM images, LLLT significantly increased the number of hair cells in middle and basal turns. Hearing was significantly improved by laser irradiation. After LLLT treatment, both the hearing threshold and hair-cell count significantly improved.

  17. The Effect of Erythropoietin on S100 Protein Expression in Cochlea After Acoustic Overstimulation: An Experimental Study

    Directory of Open Access Journals (Sweden)

    Gulsen Gurgen

    2014-03-01

    Full Text Available Aim: To investigate the effect of Erythropoietin on acoustically overstimulated rat spiral ganglion neurons (SGNs using S100 protein immunostaining.Material and Method: Twenty-two Wistar albino rats were divided into three groups: healthy control group (n=7, Saline solution (n=7 and Erythropoietin injection groups (n=8. Saline solution and Erythropoietin injection groups received white noise (100 dB SPL for 3 hours. Cochlear sections were stained by silver staining technique and immunostained by S100 antibody. Results: Histochemical analysis of silver staining sections revealed normal structure and a weak staining in SGNs of healthy control group. However, dark-black cytoplasmic staining, cellular shrinkage and degeneration were detected in saline injection group. On the other hand, a few weakly stained neurons were observed in erythropoietin injection group. S100 staining demonstrated strong reaction in Schwann cells and myelin sheaths of SGNs in healthy control group (p<0.05. In saline solution injection group, Schwann cells showed moderate S100 reaction and other regions of SGNs showed weak reaction (p<0.05. In erythropoietin injection group, strong S100 expression almost similar to the healthy control group was determined, although there was an occasional decrease. Discussion: Erythropoetin may prevent noise induced SGN degeneration via protecting the Schwann cells in rat cochlea.

  18. Tetramethylammonium for in vivo marking of the cross-sectional area of the scala media in the guinea pig cochlea.

    Science.gov (United States)

    Salt, A N; DeMott, J

    1992-01-01

    A physiologic technique was developed to measure endolymphatic cross-sectional area in vivo using tetramethylammonium (TMA) as a volume marker. The technique was evaluated in guinea pigs as an animal model. In the method, the cochlea was exposed surgically and TMA was injected into endolymph of the second turn at a constant rate by iontophoresis. The concentration of TMA was monitored during and after the injection using ion-selective electrodes. Cross-section estimates derived from the TMA concentration measurements were compared in normal animals and animals in which endolymphatic hydrops had been induced by ablation of the endolymphatic duct and sac 8 weeks earlier. The method demonstrated a mean increase in cross-sectional area of 258% in the hydropic group. Individually measured area values were compared with action potential threshold shifts and the magnitude of the endocochlear potential (EP). Hydropic animals typically showed an increase in threshold to 2 kHz stimuli and a decrease in EP. However, the degree of threshold shift or EP decrease did not correlate well with the degree of hydrops present.

  19. The cochlear nerve canal and internal auditory canal in children with normal cochlea but cochlear nerve deficiency

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Fei; Li, Jianhong; Xian, Junfang; Wang, Zhenchang [Dept. of Radiology, Beijing Tongren Hospital, Capital Medical Univ., Beijing (China)], e-mail: cjr.wzhch@vip.163.com; Mo, Lingyan [Dept. of Otorhinolaryngology, Beijing Tongren Hospital, Capital Medical Univ., Beijing (China)

    2013-04-15

    Background: There is an increasing frequency of requests for cochlear implantation (CI) in deaf children and more detailed image information is necessary for selecting appropriate candidates. Cochlear nerve deficiency (CND) is a contraindication to CI. Magnetic resonance imaging (MRI) has been used to evaluate the integrity of the cochlear nerve. The abnormalities of the cochlear nerve canal (CNC) and internal auditory canal (IAC) have been reported to be associated with CND. Purpose: To correlate CNC manifestation, size, and IAC diameter on high-resolution CT (HRCT) with CND diagnosed by MRI in children. Material and Methods: HRCT images from 35 sensorineurally deaf children who had normal cochlea but bilateral or unilateral CND diagnosed by MRI were studied retrospectively. The CNC and IAC manifestation and size were assessed and correlated with CND. Results: CND was diagnosed by MRI in 54/70 ears (77.1%). Thirty-two ears had an absent cochlear nerve (59.3%), while 22 ears had a small cochlear nerve (40.7%). The CNC diameter was <1.5 mm in 36 ears (66.7%). The CNC diameter ranged between 1.5 and 2.0 mm in seven ears (13.0%) and was >2.0 mm in 11 ears (20.4%). The IAC diameter was <3.0 mm in 25 ears (46.3%) and >3.0 mm in 29 ears (53.7%). Conclusion: The hypoplastic CNC might be more highly indicative of CND than that of a narrow IAC.

  20. The cochlear nerve canal and internal auditory canal in children with normal cochlea but cochlear nerve deficiency

    International Nuclear Information System (INIS)

    Yan, Fei; Li, Jianhong; Xian, Junfang; Wang, Zhenchang; Mo, Lingyan

    2013-01-01

    Background: There is an increasing frequency of requests for cochlear implantation (CI) in deaf children and more detailed image information is necessary for selecting appropriate candidates. Cochlear nerve deficiency (CND) is a contraindication to CI. Magnetic resonance imaging (MRI) has been used to evaluate the integrity of the cochlear nerve. The abnormalities of the cochlear nerve canal (CNC) and internal auditory canal (IAC) have been reported to be associated with CND. Purpose: To correlate CNC manifestation, size, and IAC diameter on high-resolution CT (HRCT) with CND diagnosed by MRI in children. Material and Methods: HRCT images from 35 sensorineurally deaf children who had normal cochlea but bilateral or unilateral CND diagnosed by MRI were studied retrospectively. The CNC and IAC manifestation and size were assessed and correlated with CND. Results: CND was diagnosed by MRI in 54/70 ears (77.1%). Thirty-two ears had an absent cochlear nerve (59.3%), while 22 ears had a small cochlear nerve (40.7%). The CNC diameter was 2.0 mm in 11 ears (20.4%). The IAC diameter was 3.0 mm in 29 ears (53.7%). Conclusion: The hypoplastic CNC might be more highly indicative of CND than that of a narrow IAC

  1. Mammalian Auditory Hair Cell Bundle Stiffness Affects Frequency Tuning by Increasing Coupling along the Length of the Cochlea.

    Science.gov (United States)

    Dewey, James B; Xia, Anping; Müller, Ulrich; Belyantseva, Inna A; Applegate, Brian E; Oghalai, John S

    2018-06-05

    The stereociliary bundles of cochlear hair cells convert mechanical vibrations into the electrical signals required for auditory sensation. While the stiffness of the bundles strongly influences mechanotransduction, its influence on the vibratory response of the cochlear partition is unclear. To assess this, we measured cochlear vibrations in mutant mice with reduced bundle stiffness or with a tectorial membrane (TM) that is detached from the sensory epithelium. We found that reducing bundle stiffness decreased the high-frequency extent and sharpened the tuning of vibratory responses obtained postmortem. Detaching the TM further reduced the high-frequency extent of the vibrations but also lowered the partition's resonant frequency. Together, these results demonstrate that the bundle's stiffness and attachment to the TM contribute to passive longitudinal coupling in the cochlea. We conclude that the stereociliary bundles and TM interact to facilitate passive-wave propagation to more apical locations, possibly enhancing active-wave amplification in vivo. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

  2. Long-term monitoring reveals an avian species credit in secondary forest patches of Costa Rica

    Directory of Open Access Journals (Sweden)

    Steven C. Latta

    2017-06-01

    Full Text Available Degraded and secondary forests comprise approximately 50% of remaining tropical forest. Bird community characteristics and population trends in secondary forests are infrequently studied, but secondary forest may serve as a “safety net” for tropical biodiversity. Less understood is the occurrence of time-delayed, community-level dynamics such as an extinction debt of specialist species or a species credit resulting from the recolonization of forest patches by extirpated species. We sought to elucidate patterns and magnitudes of temporal change in avian communities in secondary forest patches in Southern Costa Rica biannually over a 10 year period during the late breeding season and mid-winter. We classified birds caught in mist nets or recorded in point counts by residency status, and further grouped them based on preferred habitat, sensitivity to disturbance, conservation priority, foraging guild, and foraging strata. Using hierarchical, mixed-effects models we tested for trends among species that share traits. We found that permanent-resident species increased over time relative to migrants. In both seasons, primary forest species generally increased while species typical of secondary forest, scrub, or edge declined. Species relatively sensitive to habitat disturbance increased significantly over time, whereas birds less sensitive to disturbance decreased. Similarly, generalists with higher habitat breadth scores declined. Because, we found very few changes in vegetation characteristics in secondary forest patches, shifts in the avian community toward primary forest species represent a species credit and are likely related to vegetation changes in the broader landscape. We suggest that natural regeneration and maturation of secondary forests should be recognized as a positive conservation development of potential benefit even to species typical of primary forest.

  3. Avian frugivory and seed dispersal of Indian Sandalwood Santalum album in Tamil Nadu, India

    Directory of Open Access Journals (Sweden)

    P. Balasubramanian

    2011-05-01

    Full Text Available Santalum album, a medium sized evergreen tree found in dry forest tracts of the Deccan Peninsula, India is vulnerable (IUCN and red listed species in southern India. The paper discusses the role of avian frugivores in seed dissemination of S.album in Tamil Nadu. Observations from different locations of Western and Eastern Ghats of Tamil Nadu are presented. The forest type of the study sites comprise of southern dry mixed deciduous forest. Extended watches of 3-hr duration were made on focal trees. During the extended observations, the observer noted the name of the visitor, frequency of fruit-feeding visits by different species, and fruit handling behaviour. A total of 10 species of birds and Three-striped Palm Squirrel foraged fruit crops. Birds constituted the principal seed dispersers of Santalum album. Role of Indian Grey Hornbill in regeneration of S. album was evidenced by the presence of sandalwood seedlings in hornbill’s nest middens. Although bulbuls made frequent foraging visits, they ate the fruits in piecemeal and did not move the seeds away from the parent trees. Among the avian foragers, Asian Koel, Common Myna, Brahminy Starling, Brown-headed Barbet, White-headed Babbler and Indian Grey Hornbill constituted the major seed dispersers of S.album. These birds visited the fruit crops more frequently and swallowed the fruits wholly. Conservation efforts need to focus in providing a healthy habitat for the seed dispersing birds such as koel, as the population of sandalwood tree is dwindling in the wild.

  4. The avian fossil record in Insular Southeast Asia and its implications for avian biogeography and palaeoecology

    Directory of Open Access Journals (Sweden)

    Hanneke J.M. Meijer

    2014-03-01

    Full Text Available Excavations and studies of existing collections during the last decades have significantly increased the abundance as well as the diversity of the avian fossil record for Insular Southeast Asia. The avian fossil record covers the Eocene through the Holocene, with the majority of bird fossils Pleistocene in age. Fossil bird skeletal remains represent at least 63 species in 54 genera and 27 families, and two ichnospecies are represented by fossil footprints. Birds of prey, owls and swiftlets are common elements. Extinctions seem to have been few, suggesting continuity of avian lineages since at least the Late Pleistocene, although some shifts in species ranges have occurred in response to climatic change. Similarities between the Late Pleistocene avifaunas of Flores and Java suggest a dispersal route across southern Sundaland. Late Pleistocene assemblages of Niah Cave (Borneo and Liang Bua (Flores support the rainforest refugium hypothesis in Southeast Asia as they indicate the persistence of forest cover, at least locally, throughout the Late Pleistocene and Holocene.

  5. Regeneration performance of CO2-rich solvents by using membrane vacuum regeneration technology: Relationships between absorbent structure and regeneration efficiency

    International Nuclear Information System (INIS)

    Yan, Shuiping; Fang, Mengxiang; Wang, Zhen; Luo, Zhongyang

    2012-01-01

    Highlights: ► MVR may be viable to successfully use less valuable heat to replace high grade steam. ► Increasing OH and amine groups will increase the regeneration efficiency. ► Absorbents with a four carbon chain length will be more attractive to MVR. ► Amino acid salts will be more appropriate for MVR. ► HRM conducted at ambient pressure and low temperature is inferior to MVR. -- Abstract: In order to give a better understanding for the selection of suitable absorbents for the novel membrane vacuum regeneration technology (MVR) which has the potential to reduce CO 2 energy requirement by utilizing the waste heat or low-grade energy, an experimental study to determine the relationships between chemical structure and vacuum regeneration behavior of CO 2 absorbents at 70 °C and 10 kPa was performed. Eleven typical absorbents with different functional groups in their chemical structures were investigated in terms of vacuum regeneration efficiencies. Results showed that the regeneration efficiency decreased with an increase of number of activated hydrogen atom in amine group and decreased with the number of hydroxyl group. Especially, more attention should be paid to these alkanolamines with one hydrogen atom in amine group and two or more hydroxyl groups in the structures due to their better comprehensive performance in regeneration, absorbent loss and CO 2 absorption aspects. Increasing the carbon chain length and amine groups in the absorbent structure contributed to the improvement of regeneration performance and reduction of absorbent volatile loss. These absorbents with a four carbon chain length bonded at amine group might be more attractive to MVR. Furthermore, polyamines were superior to monoamines in terms of higher regeneration efficiencies and lower absorbent losses. Additionally, the individual effects of the potassium carboxylate group and hydroxymethylene group were also compared in this study. Results showed that amino acid salts were more

  6. Microwave Regenerable Air Purification Device

    Science.gov (United States)

    Atwater, James E.; Holtsnider, John T.; Wheeler, Richard R., Jr.

    1996-01-01

    The feasibility of using microwave power to thermally regenerate sorbents loaded with water vapor, CO2, and organic contaminants has been rigorously demonstrated. Sorbents challenged with air containing 0.5% CO2, 300 ppm acetone, 50 ppm trichloroethylene, and saturated with water vapor have been regenerated, singly and in combination. Microwave transmission, reflection, and phase shift has also been determined for a variety of sorbents over the frequency range between 1.3-2.7 GHz. This innovative technology offers the potential for significant energy savings in comparison to current resistive heating methods because energy is absorbed directly by the material to be heated. Conductive, convective and radiative losses are minimized. Extremely rapid heating is also possible, i.e., 1400 C in less than 60 seconds. Microwave powered thermal desorption is directly applicable to the needs of Advance Life Support in general, and of EVA in particular. Additionally, the applicability of two specific commercial applications arising from this technology have been demonstrated: the recovery for re-use of acetone (and similar solvents) from industrial waste streams using a carbon based molecular sieve; and the separation and destruction of trichloroethylene using ZSM-5 synthetic zeolite catalyst, a predominant halocarbon environmental contaminant. Based upon these results, Phase II development is strongly recommended.

  7. Liver Development, Regeneration, and Carcinogenesis

    Directory of Open Access Journals (Sweden)

    Janet W. C. Kung

    2010-01-01

    Full Text Available The identification of putative liver stem cells has brought closer the previously separate fields of liver development, regeneration, and carcinogenesis. Significant overlaps in the regulation of these processes are now being described. For example, studies in embryonic liver development have already provided the basis for directed differentiation of human embryonic stem cells and induced pluripotent stem cells into hepatocyte-like cells. As a result, the understanding of the cell biology of proliferation and differentiation in the liver has been improved. This knowledge can be used to improve the function of hepatocyte-like cells for drug testing, bioartificial livers, and transplantation. In parallel, the mechanisms regulating cancer cell biology are now clearer, providing fertile soil for novel therapeutic approaches. Recognition of the relationships between development, regeneration, and carcinogenesis, and the increasing evidence for the role of stem cells in all of these areas, has sparked fresh enthusiasm in understanding the underlying molecular mechanisms and has led to new targeted therapies for liver cirrhosis and primary liver cancers.

  8. Regeneration of Pelargonium in vitro

    Directory of Open Access Journals (Sweden)

    Agnieszka Wojtania

    2013-12-01

    Full Text Available Pelargonium sp. has been a subject of numerous studies to deterimine the effec tiveness of in vitro techniques to produce a large number of pathogen-free plants. Regeneration of pelargonium plants from the different initial explants as well via organogenesis as via somatic embryogenesis has been obtained. The most effective adventitious shoot formation has been achieved from shoot tips and axillary buds using cytokinin or cytokinin/auxin combinations. Leaf explants, whose general have lower organogenic potency, regenerate better in the presence of thidiazuron. This growth regulator stimulate the somatic embryos production from hypocotyl and cotyledone explants too. The main problem in tissue culture propagation of Pelargonium has been the high tendency to formation of vigorously growing callus with low organogenic potency and rapid senescence of cultures. Moreover, the significant differen ces in requirements to the medium composition (minerals, organic compounds and growth regulators between Pelargonium cultivars has been observed. This makes difficult to develop an universaI method of Pelargonium micropropagation.

  9. Avian Influenza in Migratory Birds : Regional Surveillance and ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    The Asia Partnership for Avian Influenza Research (APAIR) brings together research agencies and ... Chinese Academy of Sciences. Institution Country. China. Institution Website ... Building resilience through socially equitable climate action.

  10. Status of Avian Research at the National Renewable Energy Laboratory

    International Nuclear Information System (INIS)

    Sinclair, K.

    2001-01-01

    As the use of wind energy expands across the United States, concerns about the impacts of commercial wind farms on bird and bat populations are frequently raised. Two primary areas of concern are (1) possible litigation resulting from the killing of even one bird if it is protected by the Migratory Bird Treaty Act, the Endangered Species Act, or both; and (2) the effect of avian mortality on bird populations. To properly address these concerns, the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) supports scientifically based avian/wind power interaction research. In this paper I describe NREL's field-based research projects and summarize the status of the research. I also summarize NREL's other research activities, including lab-based vision research to increase the visibility of moving turbine blades and avian acoustic research, as well as our collaborative efforts with the National Wind Coordinating Committee's Avian Subcommittee

  11. Comparative genomics reveals insights into avian genome evolution and adaptation

    Science.gov (United States)

    Zhang, Guojie; Li, Cai; Li, Qiye; Li, Bo; Larkin, Denis M.; Lee, Chul; Storz, Jay F.; Antunes, Agostinho; Greenwold, Matthew J.; Meredith, Robert W.; Ödeen, Anders; Cui, Jie; Zhou, Qi; Xu, Luohao; Pan, Hailin; Wang, Zongji; Jin, Lijun; Zhang, Pei; Hu, Haofu; Yang, Wei; Hu, Jiang; Xiao, Jin; Yang, Zhikai; Liu, Yang; Xie, Qiaolin; Yu, Hao; Lian, Jinmin; Wen, Ping; Zhang, Fang; Li, Hui; Zeng, Yongli; Xiong, Zijun; Liu, Shiping; Zhou, Long; Huang, Zhiyong; An, Na; Wang, Jie; Zheng, Qiumei; Xiong, Yingqi; Wang, Guangbiao; Wang, Bo; Wang, Jingjing; Fan, Yu; da Fonseca, Rute R.; Alfaro-Núñez, Alonzo; Schubert, Mikkel; Orlando, Ludovic; Mourier, Tobias; Howard, Jason T.; Ganapathy, Ganeshkumar; Pfenning, Andreas; Whitney, Osceola; Rivas, Miriam V.; Hara, Erina; Smith, Julia; Farré, Marta; Narayan, Jitendra; Slavov, Gancho; Romanov, Michael N; Borges, Rui; Machado, João Paulo; Khan, Imran; Springer, Mark S.; Gatesy, John; Hoffmann, Federico G.; Opazo, Juan C.; Håstad, Olle; Sawyer, Roger H.; Kim, Heebal; Kim, Kyu-Won; Kim, Hyeon Jeong; Cho, Seoae; Li, Ning; Huang, Yinhua; Bruford, Michael W.; Zhan, Xiangjiang; Dixon, Andrew; Bertelsen, Mads F.; Derryberry, Elizabeth; Warren, Wesley; Wilson, Richard K; Li, Shengbin; Ray, David A.; Green, Richard E.; O’Brien, Stephen J.; Griffin, Darren; Johnson, Warren E.; Haussler, David; Ryder, Oliver A.; Willerslev, Eske; Graves, Gary R.; Alström, Per; Fjeldså, Jon; Mindell, David P.; Edwards, Scott V.; Braun, Edward L.; Rahbek, Carsten; Burt, David W.; Houde, Peter; Zhang, Yong; Yang, Huanming; Wang, Jian; Jarvis, Erich D.; Gilbert, M. Thomas P.; Wang, Jun

    2015-01-01

    Birds are the most species-rich class of tetrapod vertebrates and have wide relevance across many research fields. We explored bird macroevolution using full genomes from 48 avian species representing all major extant clades. The avian genome is principally characterized by its constrained size, which predominantly arose because of lineage-specific erosion of repetitive elements, large segmental deletions, and gene loss. Avian genomes furthermore show a remarkably high degree of evolutionary stasis at the levels of nucleotide sequence, gene synteny, and chromosomal structure. Despite this pattern of conservation, we detected many non-neutral evolutionary changes in protein-coding genes and noncoding regions. These analyses reveal that pan-avian genomic diversity covaries with adaptations to different lifestyles and convergent evolution of traits. PMID:25504712

  12. Detection of avian nephritis virus and chicken astrovirus in Nigerian ...

    African Journals Online (AJOL)

    2012-02-28

    Feb 28, 2012 ... Avian nephritis virus (ANV) and chicken astrovirus (CAstV) are widely distributed in poultry flocks ... sheep, cats, dogs, deer, mice, turkeys, guinea fowl and ..... complex: turkey astrovirus, turkey coronavirus, and turkey reovirus.

  13. Avian Flu (H7N9) in China

    Science.gov (United States)

    ... Mobile Apps RSS Feeds Avian Flu (H7N9) in China Recommend on Facebook Tweet Share Compartir Warning - Level ... of H7N9 have been reported outside of mainland China but most of these infections have occurred among ...

  14. Prevention and Treatment of Avian Influenza A Viruses in People

    Science.gov (United States)

    ... and Treatment of Avian Influenza A Viruses in People Language: English (US) Español Recommend on Facebook Tweet ... can happen when enough virus gets into a person’s eyes, nose or mouth, or is inhaled. This ...

  15. Markov Chain Estimation of Avian Seasonal Fecundity, Presentation

    Science.gov (United States)

    Avian seasonal fecundity is of interest from evolutionary, ecological, and conservation perspectives. However, direct estimation of seasonal fecundity is difficult, especially with multibrooded birds, and models representing the renesting and quitting processes are usually requi...

  16. 2 original article non-attenuation of highly pathogenic avian

    African Journals Online (AJOL)

    Dr Oboro VO

    AFRICAN JOURNAL OF CLINICAL AND EXPERIMENTAL MICROBIOLOGY JANUARY 2010. ISBN 1595-689X ... NON-ATTENUATION OF HIGHLY PATHOGENIC AVIAN INFLUENZA. H5N1 BY .... Diagnostic PCR was conducted to determine ...

  17. Cardiac regeneration therapy: connections to cardiac physiology.

    Science.gov (United States)

    Takehara, Naofumi; Matsubara, Hiroaki

    2011-12-01

    Without heart transplantation, a large number of patients with failing hearts worldwide face poor outcomes. By means of cardiomyocyte regeneration, cardiac regeneration therapy is emerging with great promise as a means for restoring loss of cardiac function. However, the limited success of clinical trials using bone marrow-derived cells and myoblasts with heterogeneous constituents, transplanted at a wide range of cell doses, has led to disagreement on the efficacy of cell therapy. It is therefore essential to reevaluate the evidence for the efficacy of cell-based cardiac regeneration therapy, focusing on targets, materials, and methodologies. Meanwhile, the revolutionary innovation of cardiac regeneration therapy is sorely needed to help the millions of people who suffer heart failure from acquired loss of cardiomyocytes. Cardiac regeneration has been used only in limited species or as a developing process in the rodent heart; now, the possibility of cardiomyocyte turnover in the human heart is being revisited. In the pursuit of this concept, the use of cardiac stem/progenitor stem cells in the cardiac niche must be focused to usher in a second era of cardiac regeneration therapy for the severely injured heart. In addition, tissue engineering and cellular reprogramming will advance the next era of treatment that will enable current cell-based therapy to progress to "real" cardiac regeneration therapy. Although many barriers remain, the prevention of refractory heart failure through cardiac regeneration is now becoming a realistic possibility.

  18. Heat exchanger versus regenerator: A fundamental comparison

    NARCIS (Netherlands)

    Will, M.E.; Waele, de A.T.A.M.

    2005-01-01

    Irreversible processes in regenerators and heat exchangers limit the performance of cryocoolers. In this paper we compare the performance of cryocoolers, operating with regenerators and heat exchangers from a fundamental point of view. The losses in the two systems are calculated from the entropy

  19. Adventitious shoots induction and plant regeneration from ...

    African Journals Online (AJOL)

    A highly efficient regeneration system is a prerequisite step for successful genetic transformation of watermelon cultivars (Citrullus lanatus L.). The objective of this study was to establish efficient in vitro plant regeneration for three watermelon cultivars. To achieve optimal conditions for adventitious shoot induction, the ...

  20. Plant regeneration in wheat mature embryo culture

    African Journals Online (AJOL)

    Kamil Haliloğlu

    2011-11-09

    Nov 9, 2011 ... Success in genetic engineering of cereals depends on the callus formation and efficient plant regeneration system. Callus formation and plant regeneration of wheat mature embryos ... compiled by modification of methods previously mentioned in ..... of more and readily available nutrition than artificial cul-.

  1. Oak regeneration potential increased by shelterwood treatments

    Science.gov (United States)

    Richard C. Schlesinger; Ivan L. Sander; Kenneth R. Davidson

    1993-01-01

    In much of the Central Hardwood Forest Region, oak species are not regenerating well, even though large oak trees are common within the existing forests. The shelterwood method has been suggested as a potential tool for establishing and developing advanced regeneration where it is lacking. The 10-yr results from a study of several variants of the shelterwood method...

  2. Animal regeneration: ancestral character or evolutionary novelty?

    Science.gov (United States)

    Slack, Jonathan Mw

    2017-09-01

    An old question about regeneration is whether it is an ancestral character which is a general property of living matter, or whether it represents a set of specific adaptations to the different circumstances faced by different types of animal. In this review, some recent results on regeneration are assessed to see if they can throw any new light on this question. Evidence in favour of an ancestral character comes from the role of Wnt and bone morphogenetic protein signalling in controlling the pattern of whole-body regeneration in acoels, which are a basal group of bilaterian animals. On the other hand, there is some evidence for adaptive acquisition or maintenance of the regeneration of appendages based on the occurrence of severe non-lethal predation, the existence of some novel genes in regenerating organisms, and differences at the molecular level between apparently similar forms of regeneration. It is tentatively concluded that whole-body regeneration is an ancestral character although has been lost from most animal lineages. Appendage regeneration is more likely to represent a derived character resulting from many specific adaptations. © 2017 The Author.

  3. Axonal regeneration in zebrafish spinal cord

    Science.gov (United States)

    Hui, Subhra Prakash

    2018-01-01

    Abstract In the present review we discuss two interrelated events—axonal damage and repair—known to occur after spinal cord injury (SCI) in the zebrafish. Adult zebrafish are capable of regenerating axonal tracts and can restore full functionality after SCI. Unlike fish, axon regeneration in the adult mammalian central nervous system is extremely limited. As a consequence of an injury there is very little repair of disengaged axons and therefore functional deficit persists after SCI in adult mammals. In contrast, peripheral nervous system axons readily regenerate following injury and hence allow functional recovery both in mammals and fish. A better mechanistic understanding of these three scenarios could provide a more comprehensive insight into the success or failure of axonal regeneration after SCI. This review summarizes the present understanding of the cellular and molecular basis of axonal regeneration, in both the peripheral nervous system and the central nervous system, and large scale gene expression analysis is used to focus on different events during regeneration. The discovery and identification of genes involved in zebrafish spinal cord regeneration and subsequent functional experimentation will provide more insight into the endogenous mechanism of myelination and remyelination. Furthermore, precise knowledge of the mechanism underlying the extraordinary axonal regeneration process in zebrafish will also allow us to unravel the potential therapeutic strategies to be implemented for enhancing regrowth and remyelination of axons in mammals. PMID:29721326

  4. Hyperinnervation improves Xenopus laevis limb regeneration.

    Science.gov (United States)

    Mitogawa, Kazumasa; Makanae, Aki; Satoh, Akira

    2018-01-15

    Xenopus laevis (an anuran amphibian) shows limb regeneration ability between that of urodele amphibians and that of amniotes. Xenopus frogs can initiate limb regeneration but fail to form patterned limbs. Regenerated limbs mainly consist of cone-shaped cartilage without any joints or branches. These pattern defects are thought to be caused by loss of proper expressions of patterning-related genes. This study shows that hyperinnervation surgery resulted in the induction of a branching regenerate. The hyperinnervated blastema allows the identification and functional analysis of the molecules controlling this patterning of limb regeneration. This paper focuses on the nerve affects to improve Xenopus limb patterning ability during regeneration. The nerve molecules, which regulate limb patterning, were also investigated. Blastemas grown in a hyperinnervated forelimb upregulate limb patterning-related genes (shh, lmx1b, and hoxa13). Nerves projecting their axons to limbs express some growth factors (bmp7, fgf2, fgf8, and shh). Inputs of these factors to a blastema upregulated some limb patterning-related genes and resulted in changes in the cartilage patterns in the regenerates. These results indicate that additional nerve factors enhance Xenopus limb patterning-related gene expressions and limb regeneration ability, and that bmp, fgf, and shh are candidate nerve substitute factors. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  5. Identifying avian sources of faecal contamination using sterol analysis.

    Science.gov (United States)

    Devane, Megan L; Wood, David; Chappell, Andrew; Robson, Beth; Webster-Brown, Jenny; Gilpin, Brent J

    2015-10-01

    Discrimination of the source of faecal pollution in water bodies is an important step in the assessment and mitigation of public health risk. One tool for faecal source tracking is the analysis of faecal sterols which are present in faeces of animals in a range of distinctive ratios. Published ratios are able to discriminate between human and herbivore mammal faecal inputs but are of less value for identifying pollution from wildfowl, which can be a common cause of elevated bacterial indicators in rivers and streams. In this study, the sterol profiles of 50 avian-derived faecal specimens (seagulls, ducks and chickens) were examined alongside those of 57 ruminant faeces and previously published sterol profiles of human wastewater, chicken effluent and animal meatwork effluent. Two novel sterol ratios were identified as specific to avian faecal scats, which, when incorporated into a decision tree with human and herbivore mammal indicative ratios, were able to identify sterols from avian-polluted waterways. For samples where the sterol profile was not consistent with herbivore mammal or human pollution, avian pollution is indicated when the ratio of 24-ethylcholestanol/(24-ethylcholestanol + 24-ethylcoprostanol + 24-ethylepicoprostanol) is ≥0.4 (avian ratio 1) and the ratio of cholestanol/(cholestanol + coprostanol + epicoprostanol) is ≥0.5 (avian ratio 2). When avian pollution is indicated, further confirmation by targeted PCR specific markers can be employed if greater confidence in the pollution source is required. A 66% concordance between sterol ratios and current avian PCR markers was achieved when 56 water samples from polluted waterways were analysed.

  6. Avian Conservation Practices Strengthen Ecosystem Services in California Vineyards

    OpenAIRE

    Jedlicka, Julie A.; Greenberg, Russell; Letourneau, Deborah K.

    2011-01-01

    Insectivorous Western Bluebirds (Sialia mexicana) occupy vineyard nest boxes established by California winegrape growers who want to encourage avian conservation. Experimentally, the provision of available nest sites serves as an alternative to exclosure methods for isolating the potential ecosystem services provided by foraging birds. We compared the abundance and species richness of avian foragers and removal rates of sentinel prey in treatments with songbird nest boxes and controls without...

  7. Production and Characterization of an Avian Ricin Antitoxin

    Science.gov (United States)

    1992-01-15

    naturally -occurring plant and/or bacterial toxins as biological threat agents, effective antitoxins are needed for either piophylactic or causal...system, an avian antitoxin against the potent phytotoxin , ricin. will be developed and evaluated. The production of therapeutic antibodies in avian...Dynatech). PolyacrylmIde gel electrophoresis (PAGE): Acrylamide gels were prepared according to methods described by Laemmli ( Nature . 227. 1970) and

  8. (Highly pathogenic) Avian Influenza as a zoonotic agent

    OpenAIRE

    Kalthoff , Donata; Globig , Anja; Beer , Martin

    2010-01-01

    Summary Zoonotic agents challenging the world every year afresh are influenza A viruses. In the past, human pandemics caused by influenza A viruses had been occurring periodically. Wild aquatic birds are carriers of the full variety of influenza virus A subtypes, and thus, most probably constitute the natural reservoir of all influenza A viruses. Whereas avian influenza viruses in their natural avian reservoir are generally of low pathogenicity (LPAIV), some have gained virulence b...

  9. Fossil avian eggshell preserves ancient DNA

    DEFF Research Database (Denmark)

    Oskam, Charlotte L; Haile, James Seymour; McLay, Emma

    2010-01-01

    Owing to exceptional biomolecule preservation, fossil avian eggshell has been used extensively in geochronology and palaeodietary studies. Here, we show, to our knowledge, for the first time that fossil eggshell is a previously unrecognized source of ancient DNA (aDNA). We describe the successful...... isolation and amplification of DNA from fossil eggshell up to 19 ka old. aDNA was successfully characterized from eggshell obtained from New Zealand (extinct moa and ducks), Madagascar (extinct elephant birds) and Australia (emu and owl). Our data demonstrate excellent preservation of the nucleic acids......, evidenced by retrieval of both mitochondrial and nuclear DNA from many of the samples. Using confocal microscopy and quantitative PCR, this study critically evaluates approaches to maximize DNA recovery from powdered eggshell. Our quantitative PCR experiments also demonstrate that moa eggshell has...

  10. Avian Influenza spread and transmission dynamics

    Science.gov (United States)

    Bourouiba, Lydia; Gourley, Stephen A.; Liu, Rongsong; Takekawa, John Y.; Wu, Jianhong; Chen, Dongmei; Moulin, Bernard; Wu, Jianhong

    2015-01-01

    The spread of highly pathogenic avian influenza (HPAI) viruses of type A of subtype H5N1 has been a serious threat to global public health. Understanding the roles of various (migratory, wild, poultry) bird species in the transmission of these viruses is critical for designing and implementing effective control and intervention measures. Developing appropriate models and mathematical techniques to understand these roles and to evaluate the effectiveness of mitigation strategies have been a challenge. Recent development of the global health surveillance (especially satellite tracking and GIS techniques) and the mathematical theory of dynamical systems combined have gradually shown the promise of some cutting-edge methodologies and techniques in mathematical biology to meet this challenge.

  11. Complement components of nerve regeneration conditioned fluid influence the microenvironment of nerve regeneration

    Directory of Open Access Journals (Sweden)

    Guang-shuai Li

    2016-01-01

    Full Text Available Nerve regeneration conditioned fluid is secreted by nerve stumps inside a nerve regeneration chamber. A better understanding of the proteinogram of nerve regeneration conditioned fluid can provide evidence for studying the role of the microenvironment in peripheral nerve regeneration. In this study, we used cylindrical silicone tubes as the nerve regeneration chamber model for the repair of injured rat sciatic nerve. Isobaric tags for relative and absolute quantitation proteomics technology and western blot analysis confirmed that there were more than 10 complement components (complement factor I, C1q-A, C1q-B, C2, C3, C4, C5, C7, C8ß and complement factor D in the nerve regeneration conditioned fluid and each varied at different time points. These findings suggest that all these complement components have a functional role in nerve regeneration.

  12. A novel estrogen-regulated avian apolipoprotein☆

    Science.gov (United States)

    Nikolay, Birgit; Plieschnig, Julia A.; Šubik, Desiree; Schneider, Jeannine D.; Schneider, Wolfgang J.; Hermann, Marcela

    2013-01-01

    In search for yet uncharacterized proteins involved in lipid metabolism of the chicken, we have isolated a hitherto unknown protein from the serum lipoprotein fraction with a buoyant density of ≤1.063 g/ml. Data obtained by protein microsequencing and molecular cloning of cDNA defined a 537 bp cDNA encoding a precursor molecule of 178 residues. As determined by SDS-PAGE, the major circulating form of the protein, which we designate apolipoprotein-VLDL-IV (Apo-IV), has an apparent Mr of approximately 17 kDa. Northern Blot analysis of different tissues of laying hens revealed Apo-IV expression mainly in the liver and small intestine, compatible with an involvement of the protein in lipoprotein metabolism. To further investigate the biology of Apo-IV, we raised an antibody against a GST-Apo-IV fusion protein, which allowed the detection of the 17-kDa protein in rooster plasma, whereas in laying hens it was detectable only in the isolated ≤1.063 g/ml density lipoprotein fraction. Interestingly, estrogen treatment of roosters caused a reduction of Apo-IV in the liver and in the circulation to levels similar to those in mature hens. Furthermore, the antibody crossreacted with a 17-kDa protein in quail plasma, indicating conservation of Apo-IV in avian species. In search for mammalian counterparts of Apo-IV, alignment of the sequence of the novel chicken protein with those of different mammalian apolipoproteins revealed stretches with limited similarity to regions of ApoC-IV and possibly with ApoE from various mammalian species. These data suggest that Apo-IV is a newly identified avian apolipoprotein. PMID:24047540

  13. Pathogenesis of avian pneumovirus infection in turkeys.

    Science.gov (United States)

    Jirjis, F F; Noll, S L; Halvorson, D A; Nagaraja, K V; Shaw, D P

    2002-05-01

    Avian pneumovirus (APV) is the cause of a respiratory disease of turkeys characterized by coughing, ocular and nasal discharge, and swelling of the infraorbital sinuses. Sixty turkey poults were reared in isolation conditions. At 3 weeks of age, serum samples were collected and determined to be free of antibodies against APV, avian influenza, hemorrhagic enteritis, Newcastle disease, Mycoplasma gallisepticum, Mycoplasma synoviae, Mycoplasma meleagridis, Ornithobacterium rhinotracheale, and Bordetella avium. When the poults were 4 weeks old, they were inoculated with cell culture-propagated APV (APV/Minnesota/turkey/2a/97) via the conjunctival spaces and nostrils. After inoculation, four poults were euthanatized every 2 days for 14 days, and blood, swabs, and tissues were collected. Clinical signs consisting of nasal discharge, swelling of the infraorbital sinuses, and frothy ocular discharge were evident by 2 days postinoculation (PI) and persisted until day 12 PI. Mild inflammation of the mucosa of the nasal turbinates and infraorbital sinuses was present between days 2 and 10 PI. Mild inflammatory changes were seen in tracheas of poults euthanatized between days 4 and 10 PI. Antibody to APV was detected by day 7 PI. The virus was detected in tissue preparations and swabs of nasal turbinates and infraorbital sinuses by reverse transcription polymerase chain reaction, virus isolation, and immunohistochemical staining methods between days 2 and 10 PI. Virus was detected in tracheal tissue and swabs between days 2 and 6 PI using the same methods. In this experiment, turkey poults inoculated with tissue culture-propagated APV developed clinical signs similar to those seen in field cases associated with infection with this virus.

  14. Avian influenza virus risk assessment in falconry

    Directory of Open Access Journals (Sweden)

    Lüschow Dörte

    2011-04-01

    Full Text Available Abstract Background There is a continuing threat of human infections with avian influenza viruses (AIV. In this regard falconers might be a potential risk group because they have close contact to their hunting birds (raptors such as falcons and hawks as well as their avian prey such as gulls and ducks. Both (hunting birds and prey birds seem to be highly susceptible to some AIV strains, especially H5N1. We therefore conducted a field study to investigate AIV infections in falconers, their falconry birds as well as prey birds. Findings During 2 hunting seasons (2006/2007 and 2007/2008 falconers took tracheal and cloacal swabs from 1080 prey birds that were captured by their falconry birds (n = 54 in Germany. AIV-RNA of subtypes H6, H9, or H13 was detected in swabs of 4.1% of gulls (n = 74 and 3.8% of ducks (n = 53 using RT-PCR. The remaining 953 sampled prey birds and all falconry birds were negative. Blood samples of the falconry birds tested negative for AIV specific antibodies. Serum samples from all 43 falconers reacted positive in influenza A virus-specific ELISA, but remained negative using microneutralisation test against subtypes H5 and H7 and haemagglutination inhibition test against subtypes H6, H9 and H13. Conclusion Although we were able to detect AIV-RNA in samples from prey birds, the corresponding falconry birds and falconers did not become infected. Currently falconers do not seem to carry a high risk for getting infected with AIV through handling their falconry birds and their prey.

  15. Early warning: Avian flu and nuclear science

    International Nuclear Information System (INIS)

    Belak, S.

    2006-01-01

    Avian flu has spread to 51 countries, 36 this year alone, many of which are densely populated and deprived. The joint FAO/IAEA programme is working on the rapid detection of emerging diseases, including bird flu, and using nuclear and radiation techniques in the process. The problems are serious and challenging, but nuclear technologies may offer a solution. For most developing countries, TAD (transboundary animal diseases) detection is still vital. The bottleneck is their inability to rapidly detect the virus and to determine early enough whether it is H5N1 or another subtype, so that authorities can take appropriate control measures. Serious efforts are focused on the early detection of the agents. Timely recognition of such viral infections would prevent the spread of the diseases to large animal populations in huge geographic areas. Thus, the development of novel, powerful diagnostic nuclear and nuclear-related assays is a crucial issue today in veterinary research and animal health care. Molecular virology offers a range of new methods, which are able to accelerate and improve the diagnosis of infectious diseases in animals and in man. The molecular detection assays, like the polymerase chain reaction (PCR) technologies, provide possibilities for a very rapid diagnosis. The detection of viruses can be completed within hours or hopefully even within minutes with a sensitivity level of less than one pathogenic organism. Molecular approaches have contributed significantly to the rapid detection of well-established, as well as newly emerging, infectious agents such as Nipah and Hendra viruses or corona viruses in the SARS scenario and the detection and molecular characterisation of the highly pathogenic avian influenza H5N1 subtype that threatens the world today. The nucleic acid amplification assays, although they were at first expensive and cumbersome, have become relatively cheap and user-friendly tools in the diagnostic laboratories

  16. Hydroprocessing catalysts utilization and regeneration schemes

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, E.

    The catalyst reactor inventory represents an important part of the cost of hydroprocessing operation. The selection of a suitable catalyst and reactor is influenced by feedstock properties. Processes ensuring an uninterrupted operation during catalyst addition and withdrawal are preferred for processing high asphaltene and metal content feedstocks. The spent catalyst can be regenerated and returned to the operation if the extent of its deactivation is not high. The regeneration may be performed either in-situ or off-site. The former is suitable for fixed bed reactors whereas the catalyst from ebullated bed reactors must be regenerated off-site. The regeneration of spent catalysts heavily loaded with metals such as V, Ni and Fe may not be economic. Such catalysts may be suitable for metal reclamation. An environmentally safe method for catalyst disposal must be found if neither regeneration nor metal reclamation from spent catalysts can be performed.

  17. Regeneration limit of classical Shannon capacity

    Science.gov (United States)

    Sorokina, M. A.; Turitsyn, S. K.

    2014-05-01

    Since Shannon derived the seminal formula for the capacity of the additive linear white Gaussian noise channel, it has commonly been interpreted as the ultimate limit of error-free information transmission rate. However, the capacity above the corresponding linear channel limit can be achieved when noise is suppressed using nonlinear elements; that is, the regenerative function not available in linear systems. Regeneration is a fundamental concept that extends from biology to optical communications. All-optical regeneration of coherent signal has attracted particular attention. Surprisingly, the quantitative impact of regeneration on the Shannon capacity has remained unstudied. Here we propose a new method of designing regenerative transmission systems with capacity that is higher than the corresponding linear channel, and illustrate it by proposing application of the Fourier transform for efficient regeneration of multilevel multidimensional signals. The regenerative Shannon limit—the upper bound of regeneration efficiency—is derived.

  18. Avian Antimicrobial Host Defense Peptides: From Biology to Therapeutic Applications

    Directory of Open Access Journals (Sweden)

    Guolong Zhang

    2014-02-01

    Full Text Available Host defense peptides (HDPs are an important first line of defense with antimicrobial and immunomoduatory properties. Because they act on the microbial membranes or host immune cells, HDPs pose a low risk of triggering microbial resistance and therefore, are being actively investigated as a novel class of antimicrobials and vaccine adjuvants. Cathelicidins and β-defensins are two major families of HDPs in avian species. More than a dozen HDPs exist in birds, with the genes in each HDP family clustered in a single chromosomal segment, apparently as a result of gene duplication and diversification. In contrast to their mammalian counterparts that adopt various spatial conformations, mature avian cathelicidins are mostly α-helical. Avian β-defensins, on the other hand, adopt triple-stranded β-sheet structures similar to their mammalian relatives. Besides classical β-defensins, a group of avian-specific β-defensin-related peptides, namely ovodefensins, exist with a different six-cysteine motif. Like their mammalian counterparts, avian cathelicidins and defensins are derived from either myeloid or epithelial origin expressed in a majority of tissues with broad-spectrum antibacterial and immune regulatory activities. Structure-function relationship studies with several avian HDPs have led to identification of the peptide analogs with potential for use as antimicrobials and vaccine adjuvants. Dietary modulation of endogenous HDP synthesis has also emerged as a promising alternative approach to disease control and prevention in chickens.

  19. Global Dynamics of Avian Influenza Epidemic Models with Psychological Effect

    Directory of Open Access Journals (Sweden)

    Sanhong Liu

    2015-01-01

    Full Text Available Cross-sectional surveys conducted in Thailand and China after the outbreaks of the avian influenza A H5N1 and H7N9 viruses show a high degree of awareness of human avian influenza in both urban and rural populations, a higher level of proper hygienic practice among urban residents, and in particular a dramatically reduced number of visits to live markets in urban population after the influenza A H7N9 outbreak in China in 2013. In this paper, taking into account the psychological effect toward avian influenza in the human population, a bird-to-human transmission model in which the avian population exhibits saturation effect is constructed. The dynamical behavior of the model is studied by using the basic reproduction number. The results demonstrate that the saturation effect within avian population and the psychological effect in human population cannot change the stability of equilibria but can affect the number of infected humans if the disease is prevalent. Numerical simulations are given to support the theoretical results and sensitivity analyses of the basic reproduction number in terms of model parameters that are performed to seek for effective control measures for avian influenza.

  20. Fusariotoxins in Avian Species: Toxicokinetics, Metabolism and Persistence in Tissues

    Directory of Open Access Journals (Sweden)

    Philippe Guerre

    2015-06-01

    Full Text Available Fusariotoxins are mycotoxins produced by different species of the genus Fusarium whose occurrence and toxicity vary considerably. Despite the fact avian species are highly exposed to fusariotoxins, the avian species are considered as resistant to their toxic effects, partly because of low absorption and rapid elimination, thereby reducing the risk of persistence of residues in tissues destined for human consumption. This review focuses on the main fusariotoxins deoxynivalenol, T-2 and HT-2 toxins, zearalenone and fumonisin B1 and B2. The key parameters used in the toxicokinetic studies are presented along with the factors responsible for their variations. Then, each toxin is analyzed separately. Results of studies conducted with radiolabelled toxins are compared with the more recent data obtained with HPLC/MS-MS detection. The metabolic pathways of deoxynivalenol, T-2 toxin, and zearalenone are described, with attention paid to the differences among the avian species. Although no metabolite of fumonisins has been reported in avian species, some differences in toxicokinetics have been observed. All the data reviewed suggest that the toxicokinetics of fusariotoxins in avian species differs from those in mammals, and that variations among the avian species themselves should be assessed.

  1. Avian-like breathing mechanics in maniraptoran dinosaurs

    Science.gov (United States)

    Codd, Jonathan R; Manning, Phillip L; Norell, Mark A; Perry, Steven F

    2007-01-01

    In 1868 Thomas Huxley first proposed that dinosaurs were the direct ancestors of birds and subsequent analyses have identified a suite of ‘avian’ characteristics in theropod dinosaurs. Ossified uncinate processes are found in most species of extant birds and also occur in extinct non-avian maniraptoran dinosaurs. Their presence in these dinosaurs represents another morphological character linking them to Aves, and further supports the presence of an avian-like air-sac respiratory system in theropod dinosaurs, prior to the evolution of flight. Here we report a phylogenetic analysis of the presence of uncinate processes in Aves and non-avian maniraptoran dinosaurs indicating that these were homologous structures. Furthermore, recent work on Canada geese has demonstrated that uncinate processes are integral to the mechanics of avian ventilation, facilitating both inspiration and expiration. In extant birds, uncinate processes function to increase the mechanical advantage for movements of the ribs and sternum during respiration. Our study presents a mechanism whereby uncinate processes, in conjunction with lateral and ventral movements of the sternum and gastral basket, affected avian-like breathing mechanics in extinct non-avian maniraptoran dinosaurs. PMID:17986432

  2. Global dynamics of avian influenza epidemic models with psychological effect.

    Science.gov (United States)

    Liu, Sanhong; Pang, Liuyong; Ruan, Shigui; Zhang, Xinan

    2015-01-01

    Cross-sectional surveys conducted in Thailand and China after the outbreaks of the avian influenza A H5N1 and H7N9 viruses show a high degree of awareness of human avian influenza in both urban and rural populations, a higher level of proper hygienic practice among urban residents, and in particular a dramatically reduced number of visits to live markets in urban population after the influenza A H7N9 outbreak in China in 2013. In this paper, taking into account the psychological effect toward avian influenza in the human population, a bird-to-human transmission model in which the avian population exhibits saturation effect is constructed. The dynamical behavior of the model is studied by using the basic reproduction number. The results demonstrate that the saturation effect within avian population and the psychological effect in human population cannot change the stability of equilibria but can affect the number of infected humans if the disease is prevalent. Numerical simulations are given to support the theoretical results and sensitivity analyses of the basic reproduction number in terms of model parameters that are performed to seek for effective control measures for avian influenza.

  3. Fostering and Planning Urban Regeneration

    DEFF Research Database (Denmark)

    Lidegaard, Christina; Nuccio, Massimiliano; Bille, Trine

    2018-01-01

    Policy-makers and urban planners struggle to find the right formula to implement urban regeneration processes based on cultural assets, often focusing on the desired outcomes, but rarely questioning how the policy process can shape them. This paper examines different governance models...... cultural districts in the city centre. The paper contributes to the literature on cultural districts by matching specificities and contingencies attached to a particular urban area with the governance model adopted for its development. The paper claims that temporal experimentation has to be included...... for the implementation and organization of cultural districts, and evaluates how they can affect their actual realization by investigating three cases in Copenhagen, Denmark. The deindustrialization of Copenhagen left many of the city’s harbour areas disused and in turn provided the opportunity to develop three new...

  4. Gene expression changes for antioxidants pathways in the mouse cochlea: relations to age-related hearing deficits.

    Directory of Open Access Journals (Sweden)

    Sherif F Tadros

    Full Text Available Age-related hearing loss - presbycusis - is the number one neurodegenerative disorder and top communication deficit of our aged population. Like many aging disorders of the nervous system, damage from free radicals linked to production of reactive oxygen and/or nitrogen species (ROS and RNS, respectively may play key roles in disease progression. The efficacy of the antioxidant systems, e.g., glutathione and thioredoxin, is an important factor in pathophysiology of the aging nervous system. In this investigation, relations between the expression of antioxidant-related genes in the auditory portion of the inner ear - cochlea, and age-related hearing loss was explored for CBA/CaJ mice. Forty mice were classified into four groups according to age and degree of hearing loss. Cochlear mRNA samples were collected and cDNA generated. Using Affymetrix® GeneChip, the expressions of 56 antioxidant-related gene probes were analyzed to estimate the differences in gene expression between the four subject groups. The expression of Glutathione peroxidase 6, Gpx6; Thioredoxin reductase 1, Txnrd1; Isocitrate dehydrogenase 1, Idh1; and Heat shock protein 1, Hspb1; were significantly different, or showed large fold-change differences between subject groups. The Gpx6, Txnrd1 and Hspb1 gene expression changes were validated using qPCR. The Gpx6 gene was upregulated while the Txnrd1 gene was downregulated with age/hearing loss. The Hspb1 gene was found to be downregulated in middle-aged animals as well as those with mild presbycusis, whereas it was upregulated in those with severe presbycusis. These results facilitate development of future interventions to predict, prevent or slow down the progression of presbycusis.

  5. Reduced sensory stimulation alters the molecular make-up of glutamatergic hair cell synapses in the developing cochlea.

    Science.gov (United States)

    Barclay, M; Constable, R; James, N R; Thorne, P R; Montgomery, J M

    2016-06-14

    Neural activity during early development is known to alter innervation pathways in the central and peripheral nervous systems. We sought to examine how reduced sound-induced sensory activity in the cochlea affected the consolidation of glutamatergic synapses between inner hair cells (IHC) and the primary auditory neurons as these synapses play a primary role in transmitting sound information to the brain. A unilateral conductive hearing loss was induced prior to the onset of sound-mediated stimulation of the sensory hair cells, by rupturing the tympanic membrane and dislocating the auditory ossicles in the left ear of P11 mice. Auditory brainstem responses at P15 and P21 showed a 40-50-dB increase in thresholds for frequencies 8-32kHz in the dislocated ear relative to the control ear. Immunohistochemistry and confocal microscopy were subsequently used to examine the effect of this attenuation of sound stimulation on the expression of RIBEYE, which comprises the presynaptic ribbons, Shank-1, a postsynaptic scaffolding protein, and the GluA2/3 and 4 subunits of postsynaptic AMPA receptors. Our results show that dislocation did not alter the number of pre- or postsynaptic protein puncta. However, dislocation did increase the size of RIBEYE, GluA4, GluA2/3 and Shank-1 puncta, with postsynaptic changes preceding presynaptic changes. Our data suggest that a reduction in sound stimulation during auditory development induces plasticity in the molecular make-up of IHC glutamatergic synapses, but does not affect the number of these synapses. Up-regulation of synaptic proteins with sound attenuation may facilitate a compensatory increase in synaptic transmission due to the reduced sensory stimulation of the IHC. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  6. Weak Evidence of Regeneration Habitat but Strong Evidence of Regeneration Niche for a Leguminous Shrub

    Science.gov (United States)

    Delerue, Florian; Gonzalez, Maya; Michalet, Richard; Pellerin, Sylvain; Augusto, Laurent

    2015-01-01

    The identification of an ecological niche specific to the regeneration phase has mobilised significant attention. However, the importance of the regeneration niche concept remains unclear. Our main objective was to study the existence of such a regeneration niche for a leguminous shrub, Ulex europaeus. This study was carried out in southwest France in the context of water and nutrient stresses (mainly phosphorus limitation) due to the presence of nutrient-poor sandy soils. We analysed the regeneration of the species from the germination of seeds and emergence of new seedlings until the seedlings reached young shrub size. Our design included a P fertilisation treatment. We also investigated microsite characteristics (micro-topography and vegetation development) as they can interact with meteorological conditions and determine water availability for seeds and seedlings. We found that P availability controlled seedling growth and the time necessary to reach young shrub size. Water availability appeared to impact the species germination and seedlings survival. We also found that P and water availability depended on the interactions between microsite characteristics and climatic variations. Finally we found evidence that P and water availability are important ecological factors shaping the regeneration niche of the species, but we found weak evidence that any microsite would be appropriate for the regeneration of the species in the long term. Future studies regarding regeneration niches need to distinguish more clearly the ecological factors important for regeneration (the regeneration niche per se) and the physical world where the seedlings appear and develop (the regeneration habitat). PMID:26098877

  7. Weak Evidence of Regeneration Habitat but Strong Evidence of Regeneration Niche for a Leguminous Shrub.

    Directory of Open Access Journals (Sweden)

    Florian Delerue

    Full Text Available The identification of an ecological niche specific to the regeneration phase has mobilised significant attention. However, the importance of the regeneration niche concept remains unclear. Our main objective was to study the existence of such a regeneration niche for a leguminous shrub, Ulex europaeus. This study was carried out in southwest France in the context of water and nutrient stresses (mainly phosphorus limitation due to the presence of nutrient-poor sandy soils. We analysed the regeneration of the species from the germination of seeds and emergence of new seedlings until the seedlings reached young shrub size. Our design included a P fertilisation treatment. We also investigated microsite characteristics (micro-topography and vegetation development as they can interact with meteorological conditions and determine water availability for seeds and seedlings. We found that P availability controlled seedling growth and the time necessary to reach young shrub size. Water availability appeared to impact the species germination and seedlings survival. We also found that P and water availability depended on the interactions between microsite characteristics and climatic variations. Finally we found evidence that P and water availability are important ecological factors shaping the regeneration niche of the species, but we found weak evidence that any microsite would be appropriate for the regeneration of the species in the long term. Future studies regarding regeneration niches need to distinguish more clearly the ecological factors important for regeneration (the regeneration niche per se and the physical world where the seedlings appear and develop (the regeneration habitat.

  8. Changes in avian and plant communities of aspen woodlands over 12 years after livestock removal in the northwestern Great Basin

    Science.gov (United States)

    Earnst, Susan L.; Dobkin, David S.; Ballard, Jennifer A.

    2012-01-01

    Riparian and quaking aspen (Populus tremuloides) woodlands are centers of avian abundance and diversity in the western United States, but they have been affected adversely by land use practices, particularly livestock grazing. In 1990, cattle were removed from a 112,500-ha national wildlife refuge in southeastern Oregon. Thereafter, we monitored changes in vegetation and bird abundance in years 1–3 (phase 1) and 10–12 (phase 2) in 17 riparian and 9 snow-pocket aspen plots. On each 1.5-ha plot, we sampled vegetation in 6 transects. Three times during each breeding season, observers recorded all birds 50 m to each side of the plot's 150-m centerline for 25 minutes. We analyzed data with multivariate analysis of variance and paired t tests with p values adjusted for multiple comparisons. In both periods, riparian and snow-pocket aspen produced extensive regeneration of new shoots (x̄ = 2646 stems/ha and 7079 stems/ha, respectively). By phase 2, a 64% increase in medium-diameter trees in riparian stands indicated successful recruitment into the overstory, but this pattern was not seen in snow-pocket stands, where the density of trees was over 2 times greater. By phase 2 in riparian and snow-pocket stands, native forb cover had increased by 68% and 57%, respectively, mesic shrub cover had increased by 29% and 58%, and sagebrush cover had decreased by 24% and 31%. Total avian abundance increased by 33% and 39% in riparian and snow-pocket aspen, respectively, ground or understory nesters increased by 133% and 67% and overstory nesters increased by 34% and 33%. Similarly, ground or understory foragers increased by 25% and 32%, aerial foragers by 55% and 57%, and overstory foragers by 66% and 43%. We interpreted the substantial regeneration of aspen shoots, increased densities of riparian forbs and shrubs, and increased avian abundances as a multitrophic-level response to the total removal of livestock and as substantial movement toward recovery of biological integrity.

  9. Pulp regeneration: Current approaches and future challenges

    Directory of Open Access Journals (Sweden)

    Jingwen eYANG

    2016-03-01

    Full Text Available Regenerative endodontics aims to replace inflamed/necrotic pulp tissues with regenerated pulp-like tissues to revitalize teeth and improve life quality. Pulp revascularization case reports, which showed successful clinical and radiographic outcomes, indicated the possible clinical application of pulp regeneration via cell homing strategy. From a clinical point of view, functional pulp-like tissues should be regenerated with the characterization of vascularization, re-innervation, and dentin deposition with a regulated rate similar to that of normal pulp. Efficient root canal disinfection and proper size of the apical foramen are the two requisite preconditions for pulp regeneration. Progress has been made on pulp regeneration via cell homing strategies. This review focused on the requisite preconditions and cell homing strategies for pulp regeneration. In addition to the traditionally used mechanical preparation and irrigation, antibiotics, irrigation assisted with EndoVac apical negative-pressure system, and ultrasonic and laser irradiation are now being used in root canal disinfection. In addition, pulp-like tissues could be formed with the apical foramen less than 1 mm, although more studies are needed to determine the appropriate size. Moreover, signaling molecules including stromal cell derived factor (SDF-1α, basic Fibroblast Growth Factor (bFGF, Platelet Derived Growth Factor (PDGF, stem cell factor (SCF, and Granulocyte Colony-Stimulating Factor (G-CSF were used to achieve pulp-like tissue formation via a cell homing strategy. Studies on the cell sources of pulp regeneration might give some indications on the signaling molecular selection. The active recruitment of endogenous cells into root canals to regenerate pulp-like tissues is a novel concept that may offer an unprecedented opportunity for the near-term clinical translation of current biology-based therapies for dental pulp regeneration.

  10. Segmental analysis of cochlea on three-dimensional MR imaging and high-resolution CT. Application to pre-operative assessment of cochlear implant candidates

    International Nuclear Information System (INIS)

    Akiba, Hidenari; Himi, Tetsuo; Hareyama, Masato

    2002-01-01

    High-resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) have recently become standard pre-operative examinations for cochlear implant candidates. HRCT can demonstrate ossification and narrowing of the cochlea, but subtle calcification or soft tissue obstruction may not be detected by this method alone, and so conventional T2 weighted image (T2WI) on MRI has been recommended to disclose them. In this study, segmental analyses of the cochlea were made on three-dimensional MRI (3DMRI) and HRCT in order to predict cochlear implant difficulties. The study involved 59 consecutive patients with bilateral profound sensorineural hearing loss who underwent MRI and HRCT from November 1992 to February 1998. Etiologies of deafness were meningogenic labyrinthitis (n=9), tympanogenic labyrinthitis (n=12), and others (n=38). Pulse sequence of heavy T2WI was steady state free precession and 3DMRI was reconstructed by maximum intensity projection method. HRCT was reconstructed by bone algorithm focusing on the temporal bone. For alternative segmental analysis, cochleas were anatomically divided into five parts and each of them was classified by three ranks of score depending on 3DMRI or HRCT findings. There was a close correlation by ranks between the total score of the five parts on 3DMRI and HRCT (rs=0.86, P<0.001), and a statistically significant difference was identified between causes of deafness in the total score on 3DMRI or HRCT (P<0.001, respectively). There was a significant difference in the score among the five parts on each examination (P<0.001, respectively), and abnormal findings were more frequent in the inferior horizontal part (IHP) of the basal turn. Of the 35 patients who underwent cochlear implantation, no one had ossification in the IHP on HRCT and only one patient had an obstacle to implantation. When no signal void in the IHP on 3DMRI and no ossification in the IHP on HRCT were assumed to be the criteria for candidacy for cochlear

  11. (Highly pathogenic) avian influenza as a zoonotic agent.

    Science.gov (United States)

    Kalthoff, Donata; Globig, Anja; Beer, Martin

    2010-01-27

    Zoonotic agents challenging the world every year afresh are influenza A viruses. In the past, human pandemics caused by influenza A viruses had been occurring periodically. Wild aquatic birds are carriers of the full variety of influenza virus A subtypes, and thus, most probably constitute the natural reservoir of all influenza A viruses. Whereas avian influenza viruses in their natural avian reservoir are generally of low pathogenicity (LPAIV), some have gained virulence by mutation after transmission and adaptation to susceptible gallinaceous poultry. Those so-called highly pathogenic avian influenza viruses (HPAIV) then cause mass die-offs in susceptible birds and lead to tremendous economical losses when poultry is affected. Besides a number of avian influenza virus subtypes that have sporadically infected mammals, the HPAIV H5N1 Asia shows strong zoonotic characteristics and it was transmitted from birds to different mammalian species including humans. Theoretically, pandemic viruses might derive directly from avian influenza viruses or arise after genetic reassortment between viruses of avian and mammalian origin. So far, HPAIV H5N1 already meets two conditions for a pandemic virus: as a new subtype it has been hitherto unseen in the human population and it has infected at least 438 people, and caused severe illness and high lethality in 262 humans to date (August 2009). The acquisition of efficient human-to-human transmission would complete the emergence of a new pandemic virus. Therefore, fighting H5N1 at its source is the prerequisite to reduce pandemic risks posed by this virus. Other influenza viruses regarded as pandemic candidates derive from subtypes H2, H7, and H9 all of which have infected humans in the past. Here, we will give a comprehensive overview on avian influenza viruses in concern to their zoonotic potential. Copyright 2009 Elsevier B.V. All rights reserved.

  12. Aberrant regeneration of the third cranial nerve.

    Science.gov (United States)

    Shrestha, U D; Adhikari, S

    2012-01-01

    Aberrant regeneration of the third cranial nerve is most commonly due to its damage by trauma. A ten-month old child presented with the history of a fall from a four-storey building. She developed traumatic third nerve palsy and eventually the clinical features of aberrant regeneration of the third cranial nerve. The adduction of the eye improved over time. She was advised for patching for the strabismic amblyopia as well. Traumatic third nerve palsy may result in aberrant regeneration of the third cranial nerve. In younger patients, motility of the eye in different gazes may improve over time. © NEPjOPH.

  13. Antimicrobial Products Registered for Disinfection Use against Avian Influenza on Poultry Farms and Other Facilities

    Science.gov (United States)

    EPA registers disinfectants against Avian Influenza A. Although there are no antimicrobial products registered for the H5N2 subtype of Avian Influenza A virus, based on available scientific information these products will work against other HPAI strains.

  14. Rapid detection of the avian influenza virus H5N1 subtype in Egypt

    African Journals Online (AJOL)

    Dr

    highly pathogenic avian influenza virus subtype H5N1 in Egypt is threatening poultry and ... Key words: Avian influenza virus, H5N1, fluorescent antibody enzyme-linked immunosorbent assay (ELISA) ..... poultry and is potentially zoonotic.

  15. Avian vocal mimicry: a unified conceptual framework.

    Science.gov (United States)

    Dalziell, Anastasia H; Welbergen, Justin A; Igic, Branislav; Magrath, Robert D

    2015-05-01

    Mimicry is a classical example of adaptive signal design. Here, we review the current state of research into vocal mimicry in birds. Avian vocal mimicry is a conspicuous and often spectacular form of animal communication, occurring in many distantly related species. However, the proximate and ultimate causes of vocal mimicry are poorly understood. In the first part of this review, we argue that progress has been impeded by conceptual confusion over what constitutes vocal mimicry. We propose a modified version of Vane-Wright's (1980) widely used definition of mimicry. According to our definition, a vocalisation is mimetic if the behaviour of the receiver changes after perceiving the acoustic resemblance between the mimic and the model, and the behavioural change confers a selective advantage on the mimic. Mimicry is therefore specifically a functional concept where the resemblance between heterospecific sounds is a target of selection. It is distinct from other forms of vocal resemblance including those that are the result of chance or common ancestry, and those that have emerged as a by-product of other processes such as ecological convergence and selection for large song-type repertoires. Thus, our definition provides a general and functionally coherent framework for determining what constitutes vocal mimicry, and takes account of the diversity of vocalisations that incorporate heterospecific sounds. In the second part we assess and revise hypotheses for the evolution of avian vocal mimicry in the light of our new definition. Most of the current evidence is anecdotal, but the diverse contexts and acoustic structures of putative vocal mimicry suggest that mimicry has multiple functions across and within species. There is strong experimental evidence that vocal mimicry can be deceptive, and can facilitate parasitic interactions. There is also increasing support for the use of vocal mimicry in predator defence, although the mechanisms are unclear. Less progress has

  16. Laser-capture micro dissection combined with next-generation sequencing analysis of cell type-specific deafness gene expression in the mouse cochlea.

    Science.gov (United States)

    Nishio, Shin-Ya; Takumi, Yutaka; Usami, Shin-Ichi

    2017-05-01

    Cochlear implantation (CI), which directly stimulates the cochlear nerves, is the most effective and widely used medical intervention for patients with severe to profound sensorineural hearing loss. The etiology of the hearing loss is speculated to have a major influence of CI outcomes, particularly in cases resulting from mutations in genes preferentially expressed in the spiral ganglion region. To elucidate precise gene expression levels in each part of the cochlea, we performed laser-capture micro dissection in combination with next-generation sequencing analysis and determined the expression levels of all known deafness-associated genes in the organ of Corti, spiral ganglion, lateral wall, and spiral limbs. The results were generally consistent with previous reports based on immunocytochemistry or in situ hybridization. As a notable result, the genes associated with many kinds of syndromic hearing loss (such as Clpp, Hars2, Hsd17b4, Lars2 for Perrault syndrome, Polr1c and Polr1d for Treacher Collins syndrome, Ndp for Norrie Disease, Kal for Kallmann syndrome, Edn3 and Snai2 for Waardenburg Syndrome, Col4a3 for Alport syndrome, Sema3e for CHARGE syndrome, Col9a1 for Sticker syndrome, Cdh23, Cib2, Clrn1, Pcdh15, Ush1c, Ush2a, Whrn for Usher syndrome and Wfs1 for Wolfram syndrome) showed higher levels of expression in the spiral ganglion than in other parts of the cochlea. This dataset will provide a base for more detailed analysis in order to clarify gene functions in the cochlea as well as predict CI outcomes based on gene expression data. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  17. The impact of round window vs cochleostomy surgical approaches on interscalar excursions in the cochlea: Preliminary results from a flat-panel computed tomography study

    Directory of Open Access Journals (Sweden)

    Nicole T. Jiam

    2016-09-01

    Full Text Available Objective: To evaluate incidence of interscalar excursions between round window (RW and cochleostomy approaches for cochlear implant (CI insertion. Methods: This was a retrospective case-comparison. Flat-panel CT (FPCT scans for 8 CI users with Med-El standard length electrode arrays were collected. Surgical technique was identified by a combination of operative notes and FPCT imaging. Four cochleae underwent round window insertion and 4 cochleae underwent cochleostomy approaches anterior and inferior to the round window. Results: In our pilot study, cochleostomy approaches were associated with a higher likelihood of interscalar excursion. Within the cochleostomy group, we found 29% of electrode contacts (14 of 48 electrodes to be outside the scala tympani. On the other hand, 8.5% of the electrode contacts (4 of 47 electrodes in the round window insertion group were extra-scalar to the scala tympani. These displacements occurred at a mean angle of occurrence of 364° ± 133°, near the apex of the cochlea. Round window electrode displacements tend to localize at angle of occurrences of 400° or greater. Cochleostomy electrodes occurred at an angle of occurrence of 19°–490°. Conclusions: Currently, the optimal surgical approach for standard CI electrode insertion is highly debated, to a certain extent due to a lack of post-operative assessment of intracochlear electrode contact. Based on our preliminary findings, cochleostomy approach is associated with an increased likelihood of interscalar excursions, and these findings should be further evaluated with future prospective studies. Keywords: Cochlear implantation, Round window insertion, Cochleostomy, Interscalar excursion, Electrode position, Flat-panel computed tomography, Surgical approach

  18. Increased signal intensity of the cochlea on pre- and post-contrast enhanced 3D-FLAIR in patients with vestibular schwannoma

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, Masahiro; Naganawa, Shinji; Kawai, Hisashi; Nihashi, Takashi [Nagoya University, Department of Radiology, Graduate School of Medicine, Nagoya (Japan); Fukatsu, Hiroshi [Aichi Medical University Hospital, Department of Medical Informatics, Nagakute (Japan); Nakashima, Tsutomu [Nagoya University, Department of Otorhinolaryngology, Graduate School of Medicine, Nagoya (Japan)

    2009-12-15

    In the vestibular schwannoma patients, the pathophysiologic mechanism of inner ear involvement is still unclear. We investigated the status of the cochleae in patients with vestibular schwannoma by evaluating the signal intensity of cochlear fluid on pre- and post-contrast enhanced thin section three-dimensional fluid-attenuated inversion recovery (3D-FLAIR). Twenty-eight patients were retrospectively analyzed. Post-contrast images were obtained in 18 patients, and 20 patients had the records of their pure-tone audiometry. Regions of interest of both cochleae (C) and of the medulla oblongata (M) were determined on 3D-FLAIR images by referring to 3D heavily T2-weighted images on a workstation. The signal intensity ratio between C and M on the 3D-FLAIR images (CM ratio) was then evaluated. In addition, correlation between the CM ratio and the hearing level was also evaluated. The CM ratio of the affected side was significantly higher than that of the unaffected side (p < 0.001). In the affected side, post-contrast signal elevation was observed (p < 0.005). In 13 patients (26 cochleae) who underwent both gadolinium injection and the pure-tone audiometry, the post-contrast CM ratio correlated with hearing level (p < 0.05). The results of the present study suggest that alteration of cochlear fluid composition and increased permeability of the blood-labyrinthine barrier exist in the affected side in patients with vestibular schwannoma. Furthermore, although weak, positive correlation between post-contrast cochlear signal intensity on 3D-FLAIR and hearing level warrants further study to clarify the relationship between 3D-FLAIR findings and prognosis of hearing preservation surgery. (orig.)

  19. Selective retrograde labeling of lateral olivocochlear neurons in the brainstem based on preferential uptake of 3H-D-aspartic acid in the cochlea

    International Nuclear Information System (INIS)

    Ryan, A.F.; Schwartz, I.R.; Helfert, R.H.; Keithley, E.; Wang, Z.X.

    1987-01-01

    We have previously shown that perfusion of the gerbil cochlea with probe concentrations of 3 H-D-aspartic acid (D-ASP) results in immediate, selective labeling of 50-60% of the efferent terminals under the inner hair cells, presumably by high-affinity uptake. The present study was undertaken to determine the origin of these endings. Twenty-four hours after cochlear perfusion with D-ASP, labeled neurons were observed in the ipsilateral, and to a much lesser extent in the contralateral, lateral superior olivary nucleus (LSO). The cells were small, primarily fusiform, and showed fewer synaptic contacts than other LSO cells. Combined transport of D-ASP and horseradish peroxidase indicated that all olivocochlear neurons within the LSO that projected to the injected cochlea were labeled by D-ASP. Labeled fibers coursed dorsally from the LSO, joined contralateral fibers that had passed under the floor of the fourth ventricle, and entered the VIIIth nerve root at its ventromedial edge. Adjacent to the ventral cochlear nucleus (VCN), densely labeled collateral fibers crossed the nerve root to enter the VCN. Labeled fibers and terminals were prominent in the central VCN. Neither retrograde transport of D-ASP by medial olivocochlear and vestibular efferents nor anterograde transport by VIIIth nerve afferents was observed. The D-ASP-labeled cells and fibers are clearly lateral olivocochlear efferents. Retrograde transport of D-ASP thus allows the cells, axons, and collaterals of the lateral olivocochlear system to be studied, morphologically, in isolation from other cells that project to the cochlea. Since the olivocochlear neurons are almost certainly cholinergic, retrograde amino acid transport does not necessarily identify the primary neurotransmitter of a neuron. Rather, it indicates the presence of selective uptake by the processes of that neuron at the site of amino acid injection

  20. Increased signal intensity of the cochlea on pre- and post-contrast enhanced 3D-FLAIR in patients with vestibular schwannoma

    International Nuclear Information System (INIS)

    Yamazaki, Masahiro; Naganawa, Shinji; Kawai, Hisashi; Nihashi, Takashi; Fukatsu, Hiroshi; Nakashima, Tsutomu

    2009-01-01

    In the vestibular schwannoma patients, the pathophysiologic mechanism of inner ear involvement is still unclear. We investigated the status of the cochleae in patients with vestibular schwannoma by evaluating the signal intensity of cochlear fluid on pre- and post-contrast enhanced thin section three-dimensional fluid-attenuated inversion recovery (3D-FLAIR). Twenty-eight patients were retrospectively analyzed. Post-contrast images were obtained in 18 patients, and 20 patients had the records of their pure-tone audiometry. Regions of interest of both cochleae (C) and of the medulla oblongata (M) were determined on 3D-FLAIR images by referring to 3D heavily T2-weighted images on a workstation. The signal intensity ratio between C and M on the 3D-FLAIR images (CM ratio) was then evaluated. In addition, correlation between the CM ratio and the hearing level was also evaluated. The CM ratio of the affected side was significantly higher than that of the unaffected side (p < 0.001). In the affected side, post-contrast signal elevation was observed (p < 0.005). In 13 patients (26 cochleae) who underwent both gadolinium injection and the pure-tone audiometry, the post-contrast CM ratio correlated with hearing level (p < 0.05). The results of the present study suggest that alteration of cochlear fluid composition and increased permeability of the blood-labyrinthine barrier exist in the affected side in patients with vestibular schwannoma. Furthermore, although weak, positive correlation between post-contrast cochlear signal intensity on 3D-FLAIR and hearing level warrants further study to clarify the relationship between 3D-FLAIR findings and prognosis of hearing preservation surgery. (orig.)

  1. Normal tissue complication probability modeling for cochlea constraints to avoid causing tinnitus after head-and-neck intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Lee, Tsair-Fwu; Yeh, Shyh-An; Chao, Pei-Ju; Chang, Liyun; Chiu, Chien-Liang; Ting, Hui-Min; Wang, Hung-Yu; Huang, Yu-Jie

    2015-01-01

    Radiation-induced tinnitus is a side effect of radiotherapy in the inner ear for cancers of the head and neck. Effective dose constraints for protecting the cochlea are under-reported. The aim of this study is to determine the cochlea dose limitation to avoid causing tinnitus after head-and-neck cancer (HNC) intensity-modulated radiation therapy (IMRT). In total 211 patients with HNC were included; the side effects of radiotherapy were investigated for 422 inner ears in the cohort. Forty-nine of the four hundred and twenty-two samples (11.6 %) developed grade 2+ tinnitus symptoms after IMRT, as diagnosed by a clinician. The Late Effects of Normal Tissues–Subjective, Objective, Management, Analytic (LENT-SOMA) criteria were used for tinnitus evaluation. The logistic and Lyman-Kutcher-Burman (LKB) normal tissue complication probability (NTCP) models were used for the analyses. The NTCP-fitted parameters were TD 50 = 46.31 Gy (95 % CI, 41.46–52.50), γ 50 = 1.27 (95 % CI, 1.02–1.55), and TD 50 = 46.52 Gy (95 % CI, 41.91–53.43), m = 0.35 (95 % CI, 0.30–0.42) for the logistic and LKB models, respectively. The suggested guideline TD 20 for the tolerance dose to produce a 20 % complication rate within a specific period of time was TD 20 = 33.62 Gy (95 % CI, 30.15–38.27) (logistic) and TD 20 = 32.82 Gy (95 % CI, 29.58–37.69) (LKB). To maintain the incidence of grade 2+ tinnitus toxicity <20 % in IMRT, we suggest that the mean dose to the cochlea should be <32 Gy. However, models should not be extrapolated to other patient populations without further verification and should first be confirmed before clinical implementation

  2. Combination tones along the basilar membrane in a 3D finite element model of the cochlea with acoustic boundary layer attenuation

    Science.gov (United States)

    Böhnke, Frank; Scheunemann, Christian; Semmelbauer, Sebastian

    2018-05-01

    The propagation of traveling waves along the basilar membrane is studied in a 3D finite element model of the cochlea using single and two-tone stimulation. The advantage over former approaches is the consideration of viscous-thermal boundary layer damping which makes the usual but physically unjustified assumption of Rayleigh damping obsolete. The energy loss by viscous boundary layer damping is 70 dB lower than the actually assumed power generation by outer hair cells. The space-time course with two-tone stimulation shows the traveling waves and the periodicity of the beat frequency f2 - f1.

  3. Regenerating America: Meeting the Challenge of Building Local Economies.

    Science.gov (United States)

    Gabel, Medard; And Others

    The document includes five papers on the implications and applications of regeneration by the Regeneration Project, based in Emmaus, Pa. The first paper, "Regenerating America: Meeting the Challenge of Building Local Economies," (Medard Gabel) defines regeneration as economic recovery and growth, fostered by diversification within a…

  4. The influence of vertical and horizontal habitat structure on nationwide patterns of avian biodiversity

    Science.gov (United States)

    Patrick D. Culbert; Volker C. Radeloff; Curtis H. Flather; Josef M. Kellndorfer; Chadwick D. Rittenhouse; Anna M. Pidgeon

    2013-01-01

    With limited resources for habitat conservation, the accurate identification of high-value avian habitat is crucial. Habitat structure affects avian biodiversity but is difficult to quantify over broad extents. Our goal was to identify which measures of vertical and horizontal habitat structure are most strongly related to patterns of avian biodiversity across the...

  5. 76 FR 66032 - Availability of an Environmental Assessment for Field Testing Avian Influenza-Marek's Disease...

    Science.gov (United States)

    2011-10-25

    ... Avian Influenza-Marek's Disease Vaccine, H5 Subtype, Serotype 3, Live Marek's Disease Vector AGENCY... authorization to ship for the purpose of field testing, and then to field test, an unlicensed Avian Influenza... product: Requester: Biomune Company. Product: Avian Influenza-Marek's Disease Vaccine, H5 Subtype...

  6. 9 CFR 145.15 - Diagnostic surveillance program for low pathogenic avian influenza.

    Science.gov (United States)

    2010-01-01

    ... low pathogenic avian influenza. 145.15 Section 145.15 Animals and Animal Products ANIMAL AND PLANT... pathogenic avian influenza. (a) The Official State Agency must develop a diagnostic surveillance program for H5/H7 low pathogenic avian influenza for all poultry in the State. The exact provisions of the...

  7. An Outbreak Of Highly Pathogenic Avian Influenza (Hpai) In A Mixed ...

    African Journals Online (AJOL)

    An Outbreak Of Highly Pathogenic Avian Influenza (Hpai) In A Mixed Farm By The Introduction Of A Water Fowl. ... C A Meseko, A T Oladokun, B Shehu. Abstract. Avian influenza (AI) is caused by a range of Influenza type A viruses of high and low pathogenicity (Fauci, 2005). H5N1 Highly Pathogenic Avian Influenza (HPAI) ...

  8. Composite Matrix Regenerator for Stirling Engines

    Science.gov (United States)

    Knowles, Timothy R.

    1997-01-01

    This project concerns the design, fabrication and testing of carbon regenerators for use in Stirling power convertors. Radial fiber design with nonmetallic components offers a number of potential advantages over conventional steel regenerators: reduced conduction and pressure drop losses, and the capability for higher temperature, higher frequency operation. Diverse composite fabrication methods are explored and lessons learned are summarized. A pulsed single-blow test rig has been developed that has been used for generating thermal effectiveness data for different flow velocities. Carbon regenerators have been fabricated by carbon vapor infiltration of electroflocked preforms. Performance data in a small Stirling engine are obtained. Prototype regenerators designed for the BP-1000 power convertor were fabricated and delivered to NASA-Lewis.

  9. ADAPTATION OF REGENERANTS OF Vaccinium Corymbosum L

    African Journals Online (AJOL)

    Kutas

    2011-05-09

    May 9, 2011 ... Adaptation of regenerants of Vaccinium corymbosum ... functions of the sheet plants growing in an aseptic culture, in hothouses or open ground .... L. (Koralle) were preserved in alcohol-acetic acid (3:1). ..... and soil moisture.

  10. Chronological protein synthesis in regenerating rat liver.

    Science.gov (United States)

    He, Jinjun; Hao, Shuai; Zhang, Hao; Guo, Fuzheng; Huang, Lingyun; Xiao, Xueyuan; He, Dacheng

    2015-07-01

    Liver regeneration has been studied for decades; however, its regulation remains unclear. In this study, we report a dynamic tracing of protein synthesis in rat regenerating liver with a new proteomic technique, (35) S in vivo labeling analysis for dynamic proteomics (SiLAD). Conventional proteomic techniques typically measure protein alteration in accumulated amounts. The SiLAD technique specifically detects protein synthesis velocity instead of accumulated amounts of protein through (35) S pulse labeling of newly synthesized proteins, providing a direct way for analyzing protein synthesis variations. Consequently, protein synthesis within short as 30 min was visualized and protein regulations in the first 8 h of regenerating liver were dynamically traced. Further, the 3.5-5 h post partial hepatectomy (PHx) was shown to be an important regulatory turning point by acute regulation of many proteins in the initiation of liver regeneration. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Rapid plant regeneration of chrysanthemum (Chrysanthemum ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-05-04

    May 4, 2009 ... demand for chrysanthemum, it has become one of the first commercial targets for ... frequency of multiple shoot regeneration response was. 95 and 91%, for nodal ..... Dordrecht, The Netherlands, pp. 91-101. Prasad RN ...

  12. Grazing management that regenerates ecosystem function and ...

    African Journals Online (AJOL)

    Grazing management that regenerates ecosystem function and grazingland ... in ecosystem improvement, productivity, soil carbon and fertility, water-holding ... for sufficient time to produce resource improvement, sound animal production, and ...

  13. An experimental study of passive regenerator geometries

    DEFF Research Database (Denmark)

    Engelbrecht, Kurt; Nielsen, Kaspar Kirstein; Pryds, Nini

    2011-01-01

    Active magnetic regenerative (AMR) systems are being investigated because they represent a potentially attractive alternative to vapor compression technology. The performance of these systems is dependent on the heat transfer and pressure drop performance of the regenerator geometry. Therefore th...

  14. Fingernails Yield Clues to Limb Regeneration

    Science.gov (United States)

    ... it is involved in limb formation in mammalian embryonic development, as well as limb regeneration in amphibians. ... of the nail stem cells and the underlying layer of cells called the nail epithelium are left ...

  15. Optimization of regeneration and transformation parameters in ...

    African Journals Online (AJOL)

    PRECIOUS

    transformation and regeneration therefore optimization of these two factors is .... An analysis of variance was conducted using explants types x construct ... and significant differences between means were assessed by the. Tukey's test at 1 and ...

  16. Regeneration-associated macrophages: a novel approach to boost intrinsic regenerative capacity for axon regeneration

    Directory of Open Access Journals (Sweden)

    Min Jung Kwon

    2016-01-01

    Full Text Available Axons in central nervous system (CNS do not regenerate spontaneously after injuries such as stroke and traumatic spinal cord injury. Both intrinsic and extrinsic factors are responsible for the regeneration failure. Although intensive research efforts have been invested on extrinsic regeneration inhibitors, the extent to which glial inhibitors contribute to the regeneration failure in vivo still remains elusive. Recent experimental evidence has rekindled interests in intrinsic factors for the regulation of regeneration capacity in adult mammals. In this review, we propose that activating macrophages with pro-regenerative molecular signatures could be a novel approach for boosting intrinsic regenerative capacity of CNS neurons. Using a conditioning injury model in which regeneration of central branches of dorsal root ganglia sensory neurons is enhanced by a preceding injury to the peripheral branches, we have demonstrated that perineuronal macrophages surrounding dorsal root ganglia neurons are critically involved in the maintenance of enhanced regeneration capacity. Neuron-derived chemokine (C-C motif ligand 2 (CCL2 seems to mediate neuron-macrophage interactions conveying injury signals to perineuronal macrophages taking on a soley pro-regenerative phenotype, which we designate as regeneration-associated macrophages (RAMs. Manipulation of the CCL2 signaling could boost regeneration potential mimicking the conditioning injury, suggesting that the chemokine-mediated RAM activation could be utilized as a regenerative therapeutic strategy for CNS injuries.

  17. A numerical analysis of a reciprocating Active Magnetic Regenerator with a parallel-plate regenerator geometry

    DEFF Research Database (Denmark)

    Petersen, Thomas Frank; Pryds, Nini; Smith, Anders

    2007-01-01

    We have developed a two-dimensional model of a reciprocating Active Magnetic Regenerator(AMR) with a regenerator made of parallel plates arranged in a stack configuration. The time dependent,two-dimensional model solves the Navier-Stokes equations for the heat transfer fluid and the coupled heat...... transfer equations for the regenerator and the fluid. The model is implemented using the Finite Element Method. The model can be used to study both transient and steady-state phenomena in the AMR for any ratio of regenerator to fluid heat capacity. Results on the AMR performance for different design...

  18. Detecting emerging transmissibility of avian influenza virus in human households.

    Directory of Open Access Journals (Sweden)

    Michiel van Boven

    2007-07-01

    Full Text Available Accumulating infections of highly pathogenic H5N1 avian influenza in humans underlines the need to track the ability of these viruses to spread among humans. A human-transmissible avian influenza virus is expected to cause clusters of infections in humans living in close contact. Therefore, epidemiological analysis of infection clusters in human households is of key importance. Infection clusters may arise from transmission events from (i the animal reservoir, (ii humans who were infected by animals (primary human-to-human transmission, or (iii humans who were infected by humans (secondary human-to-human transmission. Here we propose a method of analysing household infection data to detect changes in the transmissibility of avian influenza viruses in humans at an early stage. The method is applied to an outbreak of H7N7 avian influenza virus in The Netherlands that was the cause of more than 30 human-to-human transmission events. The analyses indicate that secondary human-to-human transmission is plausible for the Dutch household infection data. Based on the estimates of the within-household transmission parameters, we evaluate the effectiveness of antiviral prophylaxis, and conclude that it is unlikely that all household infections can be prevented with current antiviral drugs. We discuss the applicability of our method for the detection of emerging human-to-human transmission of avian influenza viruses in particular, and for the analysis of within-household infection data in general.

  19. Radical-pair based avian magnetoreception

    Science.gov (United States)

    Procopio, Maria; Ritz, Thorsten

    2014-03-01

    Behavioural experiments suggest that migratory birds possess a magnetic compass sensor able to detect the direction of the geomagnetic. One hypothesis for the basis of this remarkable sensory ability is that the coherent quantum spin dynamics of photoinduced radical pair reactions transduces directional magnetic information from the geomagnetic field into changes of reaction yields, possibly involving the photoreceptor cryptochrome in the birds retina. The suggested radical-pair based avian magnetoreception has attracted attention in the field of quantum biology as an example of a biological sensor which might exploit quantum coherences for its biological function. Investigations on such a spin-based sensor have focussed on uncovering the design features for the design of a biomimetic magnetic field sensor. We study the effects of slow fluctuations in the nuclear spin environment on the directional signal. We quantitatively evaluate the robustness of signals under fluctuations on a timescale longer than the lifetime of a radical pair, utilizing two models of radical pairs. Our results suggest design principles for building a radical-pair based compass sensor that is both robust and highly directional sensitive.

  20. Target organs for avian pancreatic polypeptide

    International Nuclear Information System (INIS)

    Kimmel, J.R.; Pollock, H.G.

    1981-01-01

    The problem of the physiological function of pancreatic polypeptide (PP) has been approached by attempting to identify target organs. Avian PP (aPP) labeled with 125I at either the C-terminus (aPP-C) or the N-terminus (aPP-N) was injected into fasted chickens and allowed to circulate for 3-120 min. At the end of the equilibration period, the anesthetized bird was perfused first with saline, then with Buoin's solution. Samples of fixed tissue from various organs were collected, weighed, and counted. Control experiments consisted of coinjection of unlabeled aPP to compete for receptors. The rate of disappearance of aPP-N from plasma was greater than that of aPP-C. Binding of aPP-N by spleen, duodenum, ileum, pancreas, and bone marrow was markedly reduced by coinjection of unlabeled aPP. A similar but less marked reduction in binding was found in liver and proventriculus. aPP-C gave less conclusive results. The maximal competitive effect of unlabeled PP could be achieved in most cases with 30 microgram unlabeled aPP. It is concluded that pancreas, duodenum, ileum, spleen, and bone marrow, and probably liver and proventriculus, are target organs for aPP in the chicken and that the C-terminal region of aPP is involved in receptor binding

  1. Comparison of lead residues among avian bones

    International Nuclear Information System (INIS)

    Ethier, A.L.M.; Braune, B.M.; Scheuhammer, A.M.; Bond, D.E.

    2007-01-01

    To determine if significant differences exist in lead (Pb) accumulation in different bones, especially those most often used for bone-Pb studies in wildlife, we compared Pb concentrations in radius, ulna, humerus, femur, and tibia of Common Eider (Somateria mollissima); and radius/ulna (combined), femur, and tibia of American Woodcock (Scolopax minor). There were no significant differences in bone-Pb concentrations among woodcock bones over a wide range of Pb concentrations (3-311 μg/g). In eider, where bone-Pb concentrations were low (<10 μg/g), leg bones had significantly higher Pb concentrations (approximately 30-40%) than wing bones from the same individuals. The variation among individual birds was greater than the variation among different bones within a bird. Based on our findings, we conclude that one type of bone may be substituted for another in bone-Pb studies although the same bone type should be analyzed for all birds within a study, whenever possible. - Variability in Pb concentrations among avian bones

  2. A bibliography of references to avian cholera

    Science.gov (United States)

    Wilson, Sonoma S.

    1979-01-01

    Mrs. Wilson has made a genuine effort to include in this bibliography every significant reference to avian cholera since Louis Pasteur's articles appeared in 1880, although she recognizes the likelihood that a few have been overlooked. New listings have been added throughout 1978, but comprehensive coverage of the literature cannot be claimed beyond June of that year.Textbook accounts, because they are generally summaries of work published elsewhere, are excluded. Papers dealing primarily with the biology of Pasteurella multocida, as opposed to the disease it induces in birds, are also excluded, unless they report information of diagnostic usefulness. Short abstracts are not included unless the journals in which they are published are more widely available than those in which the complete articles appear or they are English summaries of foreign language articles.In compiling this bibliography, Mrs. Wilson has made extensive use of Biological Abstracts, the Pesticide Documentation Bulletin, and printouts generated by Bibliographic Retrieval Services, Inc. The "Literature Cited" sections of textbooks and journal articles pertinent to the subject were sources of many additional references. Regardless of the origin of the citation, its accuracy was confirmed by comparison with the original publication, except in those few instances (marked with an asterisk) when the journal was not on the shelves of the libraries accessible to us.The author will be grateful to users of the bibliography who point out errors or omissions.Wayne I. JensenMicrobiologist In Charge

  3. On the origin of avian air sacs.

    Science.gov (United States)

    Farmer, C G

    2006-11-01

    For many vertebrates the lung is the largest and lightest organ in the body cavity and for these reasons can greatly affect an organism's shape, density, and its distribution of mass; characters that are important to locomotion. In this paper non-respiratory functions of the lung are considered along with data on the respiratory capacities and gas exchange abilities of birds and crocodilians to infer the evolutionary history of the respiratory systems of dinosaurs, including birds. From a quadrupedal ancestry theropod dinosaurs evolved a bipedal posture. Bipedalism is an impressive balancing act, especially for tall animals with massive heads. During this transition selection for good balance and agility may have helped shape pulmonary morphology. Respiratory adaptations arising for bipedalism are suggested to include a reduction in costal ventilation and the use of cuirassal ventilation with a caudad expansion of the lung into the dorsal abdominal cavity. The evolution of volant animals from bipeds required yet again a major reorganization in body form. With this transition avian air sacs may have been favored because they enhanced balance and agility in flight. Finally, I propose that these hypotheses can be tested by examining the importance of the air sacs to balance and agility in extant animals and that these data will enhance our understanding of the evolution of the respiratory system in archosaurs.

  4. Avian Metapneumovirus circulation in Italian broiler farms.

    Science.gov (United States)

    Tucciarone, Claudia Maria; Franzo, Giovanni; Lupini, Caterina; Alejo, Carolina Torres; Listorti, Valeria; Mescolini, Giulia; Brandão, Paulo Eduardo; Martini, Marco; Catelli, Elena; Cecchinato, Mattia

    2018-02-01

    With increasing frequency, avian Metapneumovirus (aMPV) is reported to induce respiratory signs in chickens. An adequate knowledge of current aMPV prevalence among Italian broilers is lacking, with little information available on its economical and health impact on the poultry industry. In order to collect preliminary data on the epidemiological context of aMPV in broiler flocks, a survey was performed in areas of Northern Italy with high poultry density from 2014 to 2016. Upper respiratory tract swabs were collected and processed by A and B subtype-specific multiplex real-time reverse transcription PCR (RT-PCR). Samples were also screened for infectious bronchitis virus (IBV) by generic RT-PCR and sequencing. Productive data and respiratory signs were detailed where possible. The high prevalence of aMPV was confirmed in broilers older than 26 d and also attested in IBV-negative farms. All aMPV detections belonged to subtype B. Italian strain genetic variability was evaluated by the partial attachment (G) gene sequencing of selected strains and compared with contemporary turkey strains and previously published aMPV references, revealing no host specificity and the progressive evolution of this virus in Italy. © 2017 Poultry Science Association Inc.

  5. Emdogain--periodontal regeneration based on biomimicry.

    Science.gov (United States)

    Gestrelius, S; Lyngstadaas, S P; Hammarström, L

    2000-06-01

    Biomimicry has been introduced as a term for innovations inspired by nature [1]. Such innovations may appear in almost every part of modern society. This review on the effects of enamel matrix proteins on the formation of cementum and the development of emdogain for regeneration of periodontal tissues lost due to periodontitis shows an example of biomimicry in dentistry. Findings from clinical and laboratory investigations are summarized and the biological basis for enamel matrix-induced periodontal regeneration is discussed.

  6. DIAGNOSTICS AND REGENERATION OF COMMON RAIL INJECTORS

    Directory of Open Access Journals (Sweden)

    Łukasz KONIECZNY

    2015-03-01

    Full Text Available The article presents the methodology of Common Rail injector diagnostic, regeneration and regulation with use of professional test stands. The EPS 815 machine can be used to test and repair all BOSCH injectors fully satisfying the producer requirements and standards. The article describes an example injector diagnosis with use of such test stand and additionally presents appropriate injector regeneration and encoding techniques

  7. Brownfield regeneration: Towards strengthening social cohesion?

    Directory of Open Access Journals (Sweden)

    Minić Marta

    2016-01-01

    Full Text Available In broader terms, the paper refers to the topic of brownfield regeneration, as one of the most complex mechanisms for sustainable spatial development. In addition to the fact that brownfield regeneration demands a variety of instruments, such as: tax subsidies, the change of land use ownership, soil remediation, planning regulative amendments, etc., the complexity of brownfield regeneration is primarily seen in a number of stakeholders participating in such a process. Thus, the paper focuses on the social aspect of brownfield regeneration - precisely, on researching the community role and reviewing the possibilities for achieving the 'local' interests in complex developmental processes. The main research hypothesis is that brownfield regeneration positively affects the creation of and strengthening the social cohesion in the areas close to the brownfield site. More precisley, the paper presents the ways towards strenghtening social cohesion in the initial phase of the brownfield regeneration process, as well as the effects of such a process in its operationalisation phase on social cohesion. The thesis is examined by two main parameters: 1 participation of local community, and 2 social costs and benefits of brownfield regeneration versus greenfield investment. The research results are presented in the form of argumentative essay. In fact, the critical overview of arguments for and against the main research hypothesis is provided based on the review of interdisciplinary literature in the domain of brownfield regeneration. Such research organisation ensures the identification and description of the measures needed for strengthening social cohesion, as an utmost goal of this research. The final research contribution is about offering the guidelines for similar methodological approach in urban research.

  8. Straight-Pore Microfilter with Efficient Regeneration

    Science.gov (United States)

    Liu, Han; LaConti, Anthony B.; McCallum. Thomas J.; Schmitt, Edwin W.

    2010-01-01

    A novel, high-efficiency gas particulate filter has precise particle size screening, low pressure drop, and a simple and fast regeneration process. The regeneration process, which requires minimal material and energy consumption, can be completely automated, and the filtration performance can be restored within a very short period of time. This filter is of a novel material composite that contains the support structure and a novel coating.

  9. Abiotic factors influencing tropical dry forests regeneration

    Directory of Open Access Journals (Sweden)

    Ceccon Eliane

    2006-01-01

    Full Text Available Tropical dry forests represent nearly half the tropical forests in the world and are the ecosystems registering the greatest deterioration from the anthropogenic exploitation of the land. This paper presents a review on the dynamics of tropical dry forests regeneration and the main abiotic factors influencing this regeneration, such as seasonal nature, soil fertility and humidity, and natural and anthropic disturbances. The main purpose is to clearly understand an important part of TDF succession dynamics.

  10. Protoplast formation and regeneration in Lactobacillus delbrueckii

    OpenAIRE

    Singhvi, Mamta; Joshi, Dipti; Gaikaiwari, Shalaka; Gokhale, Digambar V.

    2010-01-01

    Method for production and regeneration of Lactobacillus delbrueckii protoplasts are described. The protoplasts were obtained by treatment with a mixture of lysozyme and mutanolysin in protoplast buffer at pH 6.5 with different osmotic stabilizers. The protoplasts were regenerated on deMan, Rogosa and Sharpe (MRS) with various osmotic stabilizers. Maximum protoplast formation was obtained in protoplast buffer with sucrose as an osmotic stabilizer using a combination of lysozyme (1 mg/ml) and m...

  11. Continuous microwave regeneration apparatus for absorption media

    Science.gov (United States)

    Smith, Douglas D.

    1999-01-01

    A method and apparatus for continuously drying and regenerating ceramic beads for use in process gas moisture drying operations such as glove boxes. A microwave energy source is coupled to a process chamber to internally heat the ceramic beads and vaporize moisture contained therein. In a preferred embodiment, the moisture laden ceramic beads are conveyed toward the microwave source by a screw mechanism. The regenerated beads flow down outside of the screw mechanism and are available to absorb additional moisture.

  12. Large scale gene expression profiles of regenerating inner ear sensory epithelia.

    Directory of Open Access Journals (Sweden)

    R David Hawkins

    2007-06-01

    Full Text Available Loss of inner ear sensory hair cells (HC is a leading cause of human hearing loss and balance disorders. Unlike mammals, many lower vertebrates can regenerate these cells. We used cross-species microarrays to examine this process in the avian inner ear. Specifically, changes in expression of over 1700 transcription factor (TF genes were investigated in hair cells of auditory and vestibular organs following treatment with two different damaging agents and regeneration in vitro. Multiple components of seven distinct known signaling pathways were clearly identifiable: TGFbeta, PAX, NOTCH, WNT, NFKappaB, INSULIN/IGF1 and AP1. Numerous components of apoptotic and cell cycle control pathways were differentially expressed, including p27(KIP and TFs that regulate its expression. A comparison of expression trends across tissues and treatments revealed identical patterns of expression that occurred at identical times during regenerative proliferation. Network analysis of the patterns of gene expression in this large dataset also revealed the additional presence of many components (and possible network interactions of estrogen receptor signaling, circadian rhythm genes and parts of the polycomb complex (among others. Equal numbers of differentially expressed genes were identified that have not yet been placed into any known pathway. Specific time points and tissues also exhibited interesting differences: For example, 45 zinc finger genes were specifically up-regulated at later stages of cochlear regeneration. These results are the first of their kind and should provide the starting point for more detailed investigations of the role of these many pathways in HC recovery, and for a description of their possible interactions.

  13. Fuel cell catholyte regenerating apparatus

    International Nuclear Information System (INIS)

    Struthers, R. C.

    1985-01-01

    A catholyte regenerating apparatus for a fuel cell having a cathode section containing a catholyte solution and wherein fuel cell reaction reduces the catholyte to gas and water. The apparatus includes means to conduct partically reduced water diluted catholyte from the fuel cell and means to conduct the gas from the fuel cell to a mixing means. An absorption tower containing a volume of gas absorbing liquid solvent receives the mixed together gas and diluted catholyte from the mixing means within the absorption column, the gas is absorbed by the solvent and the gas ladened solvent and diluted catholyte are commingled. A liquid transfer means conducts gas ladened commingled. A liquid transfer means conducts gas ladened commingled solvent and electrolyte from the absorption column to an air supply means wherein air is added and commingled therewith and a stoichiometric volume of oxygen from the air is absorbed thereby. A second liquid transfer means conducts the gas ladened commingled solvent and diluted catholyte into a catalyst column wherein the oxygen and gas react to reconstitute the catholyte from which the gas was generated wna wherein the reconstituted diluted catholyte is separated from the solvent. Recirculating means conducts the solvent from the catalyst column back into the absorption column and liquid conducting means conducts the reconstituted catholyte to a holding tank preparatory for catholyte to a holding tank preparatory for recirculation through the cathode section of the fuel cell

  14. Advances in plasma skin regeneration.

    Science.gov (United States)

    Foster, K Wade; Moy, Ronald L; Fincher, Edgar F

    2008-09-01

    Plasma skin regeneration (PSR) is a novel method of resurfacing that uses plasma energy to create a thermal effect on the skin. PSR is different from lasers, light sources, and ablative lasers in that it is not chromophore dependent and does not vaporize tissue, but leaves a layer of intact, desiccated epidermis that acts as a natural biologic dressing and promotes wound healing and rapid recovery. Histological studies performed on plasma resurfacing patients have confirmed continued collagen production, reduction of elastosis, and progressive skin rejuvenation beyond 1 year after treatment. PSR has received US Food and Drug Administration 510 (k) clearance for treatment of rhytides of the body, superficial skin lesions, actinic keratoses, viral papillomata, and seborrheic keratoses. PSR also has beneficial effects in the treatment of other conditions including dyschromias, photoaging, skin laxity, and acne scars. The safety profile of PSR is excellent, and there have been no reports of demarcation lines in perioral, periorbital, or jawline areas, as can sometimes be observed following CO2 resurfacing. PSR is effective in improving facial and periorbital rhytides and can be used on nonfacial sites, including the hands, neck, and chest. Numerous treatment protocols with variable energy settings allow for individualized treatments and provide the operator with fine control over the degree of injury and length of subsequent recovery time.

  15. Immunology Guides Skeletal Muscle Regeneration

    Directory of Open Access Journals (Sweden)

    F. Andrea Sass

    2018-03-01

    Full Text Available Soft tissue trauma of skeletal muscle is one of the most common side effects in surgery. Muscle injuries are not only caused by accident-related injuries but can also be of an iatrogenic nature as they occur during surgical interventions when the anatomical region of interest is exposed. If the extent of trauma surpasses the intrinsic regenerative capacities, signs of fatty degeneration and formation of fibrotic scar tissue can occur, and, consequentially, muscle function deteriorates or is diminished. Despite research efforts to investigate the physiological healing cascade following trauma, our understanding of the early onset of healing and how it potentially determines success or failure is still only fragmentary. This review focuses on the initial physiological pathways following skeletal muscle trauma in comparison to bone and tendon trauma and what conclusions can be drawn from new scientific insights for the development of novel therapeutic strategies. Strategies to support regeneration of muscle tissue after injury are scarce, even though muscle trauma has a high incidence. Based on tissue specific differences, possible clinical treatment options such as local immune-modulatory and cell therapeutic approaches are suggested that aim to support the endogenous regenerative potential of injured muscle tissues.

  16. Limb Regeneration in Axolotl: Is It Superhealing?

    Directory of Open Access Journals (Sweden)

    Stéphane Roy

    2006-01-01

    Full Text Available The ability of axolotls to regenerate their limbs is almost legendary. In fact, urodeles such as the axolotl are the only vertebrates that can regenerate multiple structures like their limbs, jaws, tail, spinal cord, and skin (the list goes on throughout their lives. It is therefore surprising to realize, although we have known of their regenerative potential for over 200 years, how little we understand the mechanisms behind this achievement of adult tissue morphogenesis. Many observations can be drawn between regeneration and other disciplines such as development and wound healing. In this review, we present new developments in functional analysis that will help to address the role of specific genes during the process of regeneration. We also present an analysis of the resemblance between wound healing and regeneration, and discuss whether axolotls are superhealers. A better understanding of these animals' regenerative capacity could lead to major benefits by providing regenerative medicine with directions on how to develop therapeutic approaches leading to regeneration in humans.

  17. Silymarin Accelerates Liver Regeneration after Partial Hepatectomy

    Directory of Open Access Journals (Sweden)

    Jia-Ping Wu

    2015-01-01

    Full Text Available Partial hepatectomy (PHx is a liver regeneration physiological response induced to maintain homeostasis. Liver regeneration evolved presumably to protect wild animals from catastrophic liver loss caused by toxins or tissue injury. Silymarin (Sm ability to stimulate liver regeneration has been an object of curiosity for many years. Silymarin has been investigated for use as an antioxidant and anticarcinogen. However, its use as a supportive treatment for liver damage is elusive. In this study, we fed silymarin (Sm, 25 mg/kg to male Sprague-Dawley rats for 7 weeks. Surgical 2/3 PHx was then conducted on the rats at 6 hrs, 24 hrs, and 72 hrs. Western blot and RT-PCR were conducted to detect the cell cycle activities and silymarin effects on hepatic regeneration. The results showed that silymarin enhanced liver regeneration by accelerating the cell cycle in PHx liver. Silymarin led to increased G1 phase (cyclin D1/pRb, S phase (cyclin E/E2F, G2 phase (cyclin B, and M phase (cyclin A protein and mRNA at 6 hrs, 24 hrs, and 72 hrs PHx. HGF, TGFα, and TGFβ1 growth factor expressions were also enhanced. We suggest that silymarin plays a crucial role in accelerated liver regeneration after PHx.

  18. The cancer paradigms of mammalian regeneration: can mammals regenerate as amphibians?

    Science.gov (United States)

    Sarig, Rachel; Tzahor, Eldad

    2017-04-01

    Regeneration in mammals is restricted to distinct tissues and occurs mainly by expansion and maturation of resident stem cells. During regeneration, even subtle mutations in the proliferating cells may cause a detrimental effect by eliciting abnormal differentiation or malignant transformation. Indeed, cancer in mammals has been shown to arise through deregulation of stem cells maturation, which often leads to a differentiation block and cell transformation. In contrast, lower organisms such as amphibians retain a remarkable regenerative capacity in various organs, which occurs via de- and re-differentiation of mature cells. Interestingly, regenerating amphibian cells are highly resistant to oncogenic transformation. Therapeutic approaches to improve mammalian regeneration mainly include stem-cell transplantations; but, these have proved unsuccessful in non-regenerating organs such as the heart. A recently developed approach is to induce de-differentiation of mature cardiomyocytes using factors that trigger their re-entry into the cell cycle. This novel approach raises numerous questions regarding the balance between transformation and regeneration induced by de-differentiation of mature mammalian somatic cells. Can this balance be controlled artificially? Do de-differentiated cells acquire the protection mechanisms seen in regenerating cells of lower organisms? Is this model unique to the cardiac tissue, which rarely develops tumors? This review describes regeneration processes in both mammals and lower organisms and, particularly, the ability of regenerating cells to avoid transformation. By comparing the characteristics of mammalian embryonic and somatic cells, we discuss therapeutic strategies of using various cell populations for regeneration. Finally, we describe a novel cardiac regeneration approach and its implications for regenerative medicine. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email

  19. Avian genomics lends insights into endocrine function in birds.

    Science.gov (United States)

    Mello, C V; Lovell, P V

    2018-01-15

    The genomics era has brought along the completed sequencing of a large number of bird genomes that cover a broad range of the avian phylogenetic tree (>30 orders), leading to major novel insights into avian biology and evolution. Among recent findings, the discovery that birds lack a large number of protein coding genes that are organized in highly conserved syntenic clusters in other vertebrates is very intriguing, given the physiological importance of many of these genes. A considerable number of them play prominent endocrine roles, suggesting that birds evolved compensatory genetic or physiological mechanisms that allowed them to survive and thrive in spite of these losses. While further studies are needed to establish the exact extent of avian gene losses, these findings point to birds as potentially highly relevant model organisms for exploring the genetic basis and possible therapeutic approaches for a wide range of endocrine functions and disorders. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Phylogenomic analyses data of the avian phylogenomics project

    DEFF Research Database (Denmark)

    Jarvis, Erich D; Mirarab, Siavash; Aberer, Andre J

    2015-01-01

    BACKGROUND: Determining the evolutionary relationships among the major lineages of extant birds has been one of the biggest challenges in systematic biology. To address this challenge, we assembled or collected the genomes of 48 avian species spanning most orders of birds, including all Neognathae...... and two of the five Palaeognathae orders. We used these genomes to construct a genome-scale avian phylogenetic tree and perform comparative genomic analyses. FINDINGS: Here we present the datasets associated with the phylogenomic analyses, which include sequence alignment files consisting of nucleotides......ML algorithm or when using statistical binning with the coalescence-based MP-EST algorithm (which we refer to as MP-EST*). Other data sets, such as the coding sequence of some exons, revealed other properties of genome evolution, namely convergence. CONCLUSIONS: The Avian Phylogenomics Project is the largest...

  1. Surveillance of wild birds for avian influenza virus.

    Science.gov (United States)

    Hoye, Bethany J; Munster, Vincent J; Nishiura, Hiroshi; Klaassen, Marcel; Fouchier, Ron A M

    2010-12-01

    Recent demand for increased understanding of avian influenza virus in its natural hosts, together with the development of high-throughput diagnostics, has heralded a new era in wildlife disease surveillance. However, survey design, sampling, and interpretation in the context of host populations still present major challenges. We critically reviewed current surveillance to distill a series of considerations pertinent to avian influenza virus surveillance in wild birds, including consideration of what, when, where, and how many to sample in the context of survey objectives. Recognizing that wildlife disease surveillance is logistically and financially constrained, we discuss pragmatic alternatives for achieving probability-based sampling schemes that capture this host-pathogen system. We recommend hypothesis-driven surveillance through standardized, local surveys that are, in turn, strategically compiled over broad geographic areas. Rethinking the use of existing surveillance infrastructure can thereby greatly enhance our global understanding of avian influenza and other zoonotic diseases.

  2. Laser use in avian and exotic animal medicine

    Science.gov (United States)

    Parrott, Terri

    2000-05-01

    The use of lasers in clinical avian and exotic animal practice has increased the types of surgical procedures available to the veterinarian. Tissue injury and blood loss can be minimized with both the CO2 and Diode laser. The physical properties of these lasers give them direct advantages over other types of lasers for small animal and avian surgical patients. Routine salpingohysterectomy, castration and mass removal can be accomplished with the CO2 laser. Power, pulse settings and tip diameters for the various tissues make the CO2 laser a versatile instrument in surgery. Endoscopic surgery in the avian patient has been revolutionized with the use of the Diode laser. The use of the flexible fiber system makes it amendable to both rigid and flexible scopes.

  3. The structural and functional differentiation of hair cells in a lizard’s basilar papilla suggests an operational principle of amniote cochleas

    Science.gov (United States)

    Chiappe, M. Eugenia; Kozlov, Andrei S.; Hudspeth, A. J.

    2007-01-01

    The hair cells in the mammalian cochlea are of two distinct types. Inner hair cells are responsible for transducing mechanical stimuli into electrical responses, which they forward to the brain through a copious afferent innervation. Outer hair cells, which are thought to mediate the active process that sensitizes and tunes the cochlea, possess a negligible afferent innervation. For every inner hair cell there are approximately three outer hair cells, so only a quarter of the hair cells directly deliver information to the central nervous system. Although this is a surprising feature for a sensory system, the occurrence of a similar innervation pattern in birds and crocodilians suggests that the arrangement has an adaptive value. Using a lizard with highly developed hearing, the tokay gecko, we demonstrate in the present study that the same principle operates in a third major group of terrestrial animals. We propose that the differentiation of hair cells into signaling and amplifying classes reflects incompatible strategies for the optimization of mechanoelectrical transduction and of an active process based on active hair-bundle motility. PMID:17978038

  4. The efficacy of N-acetylcysteine to protect the human cochlea from subclinical hearing loss caused by impulse noise: A controlled trial

    Directory of Open Access Journals (Sweden)

    Ann-Cathrine Lindblad

    2011-01-01

    Full Text Available In military outdoor shooting training, with safety measures enforced, the risk of a permanent, noise-induced hearing loss is very small. But urban warfare training performed indoors, with reflections from walls, might increase the risk. A question is whether antioxidants can reduce the negative effects of noise on human hearing as it does on research animals. Hearing tests were performed on a control group of 23 military officers before and after a shooting session in a bunker-like room. The experiments were repeated on another group of 11 officers with peroral adminstration of N-acetyl-cysteine (NAC, directly after the shooting. The measurements performed were tone thresholds; transient-evoked otoacoustic emissions, with and without contralateral noise; and psycho-acoustical modulation transfer function (PMTF, thresholds for brief tones in modulated noise. Effects from shooting on hearing thresholds were small, but threshold behavior supports use of NAC treatment. On the PMTF, shooting without NAC gave strong effects. Those effects were like those from continuous noise, which means that strict safety measures should be enforced. The most striking finding was that the non-linearity of the cochlea, that was strongly reduced in the group without NAC, as manifested by the PMTF-results, was practically unchanged in the NAC-group throughout the study. NAC treatment directly after shooting in a bunkerlike room seems to give some protection of the cochlea.

  5. Zirconia changes after grinding and regeneration firing.

    Science.gov (United States)

    Hatanaka, Gabriel R; Polli, Gabriela S; Fais, Laiza M G; Reis, José Maurício Dos S N; Pinelli, Lígia A P

    2017-07-01

    Despite improvements in computer-aided design and computer-aided manufacturing (CAD-CAM) systems, grinding during either laboratory procedures or clinical adjustments is often needed to modify the shape of 3 mol(%) yttria-tetragonal zirconia polycrystal (3Y-TZP) restorations. However, the best way to achieve adjustment is unclear. The purpose of this in vitro study was to evaluate the microstructural and crystallographic phase changes, flexural strength, and Weibull modulus of a 3Y-TZP zirconia after grinding with or without water cooling and regeneration firing. Ninety-six bar-shaped specimens were obtained and divided as follows: as-sintered, control; as-sintered with regeneration firing; grinding without water cooling; grinding and regeneration firing with water cooling; and grinding and regeneration firing. Grinding (0.3 mm) was performed with a 150-μm diamond rotary instrument in a high-speed handpiece. For regeneration firing, the specimens were annealed at 1000°C for 30 minutes. The crystalline phases were evaluated by using x-ray powder diffraction. A 4-point bending test was conducted (10 kN; 0.5 mm/min). The Weibull modulus was used to analyze strength reliability. The microstructure was analyzed by scanning electron microscopy. Data from the flexural strength test were evaluated using the Kruskal-Wallis and Dunn tests (α=.05). Tetragonal-to-monoclinic phase transformation was identified in the ground specimens; R regeneration firing groups showed only the tetragonal phase. The median flexural strength of as-sintered specimens was 642.0; 699.3 MPa for as-sintered specimens with regeneration firing; 770.1 MPa for grinding and water-cooled specimens; 727.3 MPa for specimens produced using water-cooled grinding and regeneration firing; 859.9 MPa for those produced by grinding; and 764.6 for those produced by grinding and regeneration firing; with statistically higher values for the ground groups. The regenerative firing did not affect the flexural

  6. [Summary of Guangdong provincial seminar on avian influenza and influenza].

    Science.gov (United States)

    Yu, Shou-yi; Chen, Qing; Hu, Gui-fang

    2005-12-01

    On 8th November 2005, an academic seminar on avian influenza and influenza in Guangdong Province was held by Guangdong Society of Tropical Medicine and the Epidemiology Committee of the Guangdong Preventive Medicine Society in Southern Medical University, addressing the current problems in epidemics of avian influenza. The specialists attending the conference arrived at the common consideration that at present, the avian influenza virus H5N1 has not the capacity to trigger an pandemic in human population, but scattered cases had been reported to increase the suspicions of H5N1 virus transmission between humans. Due attention should be paid to the tendency of expansion of the host range and epidemic area, and the possibility of disastrous influenza pandemic among human populations persists, for which rational consideration is called for, and the role of specialists should be fully recognized who are endeavoring to examine the possible scale of influenza occurrence and devise strategy to deal with the epidemic in Guangdong province according to the practical situation in China. Increased funds and investment in scientific research on avian influenza is urged for influenza prediction and surveillance, rapid and early diagnostic assays, understanding of virus variation, mechanism of H5N1 virus adaptation to human hosts, effective medicines and vaccines for prevention and therapy of avian influenza. Laboratory bio-safety control should be enforced to prevent infections originated from laboratories. The specialists appeal that the media report the news objectively and issue the public warnings against avian influenza after consulting specialists, so as to avoid unnecessary social panic.

  7. [Highly pathogenic avian influenza--monitoring of migratory waterfowl].

    Science.gov (United States)

    Otsuki, Koichi; Ito, Toshihiro

    2006-10-01

    Since 1979, the group belonging to Departments of Veterinary Microbiology, Veterinary Public Health and the Avian Zoonoses Research Centre, Faculty of Agriculture, Tottori University is continuing isolation of avian influenza virus from such migratory waterfowls as whistling swan, pintail and tufted dugs flying from Siberia and/or northern China. They have already isolated many interesting influenza viruses. Serotype of the isolates is various; some H5 and H7 and human types of viruses were also isolated; and its pathogenicity for chickens is not high. It was interested that low pathogenic H5N3 virus isolated from whistling swan acquired severe pathogenicity during passage in chicks.

  8. Movements of Birds and Avian Influenza from Asia into Alaska

    OpenAIRE

    Winker, Kevin; McCracken, Kevin G.; Gibson, Daniel D.; Pruett, Christin L.; Meier, Rose; Huettmann, Falk; Wege, Michael; Kulikova, Irina V.; Zhuravlev, Yuri N.; Perdue, Michael L.; Spackman, Erica; Suarez, David L.; Swayne, David E.

    2007-01-01

    Asian-origin avian influenza (AI) viruses are spread in part by migratory birds. In Alaska, diverse avian hosts from Asia and the Americas overlap in a region of intercontinental avifaunal mixing. This region is hypothesized to be a zone of Asia-to-America virus transfer because birds there can mingle in waters contaminated by wild-bird?origin AI viruses. Our 7 years of AI virus surveillance among waterfowl and shorebirds in this region (1998?2004; 8,254 samples) showed remarkably low infecti...

  9. The anatomy and physiology of the avian endocrine system.

    Science.gov (United States)

    Ritchie, Midge; Pilny, Anthony A

    2008-01-01

    The endocrine system of birds is comparable to that of mammals, although there are many unique aspects to consider when studying the anatomy, physiology, and biochemistry. Avian endocrinology is a field of veterinary medicine that is unfamiliar to many practitioners; however, it is important to have a comprehensive understanding when evaluating companion birds in clinical practice. This article covers the anatomy and physiology of the normal avian, and readers are referred to other articles for a more detailed explanation of altered physiology and pathology.

  10. The influence of regeneration fellings on the development of artificially regenerated beech (Fagus sylvatica L.) plantations

    Czech Academy of Sciences Publication Activity Database

    Bednář, Pavel; Černý, J.

    2014-01-01

    Roč. 62, č. 5 (2014), s. 859-867 ISSN 1211-8516 Institutional support: RVO:67179843 Keywords : European beech * regeneration felling * artificial regeneration * height * DBH – the diameter at breast-height * quality * ISF – Indirect Site Factor Subject RIV: GK - Forestry

  11. Functional hepatocellular regeneration measured by hepatobiliary scintigraphy, functional regeneration or functional hepatocytes?

    NARCIS (Netherlands)

    Olthof, Pim B.; Cieslak, Kasia P.; Bennink, Roelof J.; van Gulik, Thomas M.

    2016-01-01

    In a recent issue of this journal, Fernandes et al(1) reported on functional hepatocellular regeneration in elderly patients undergoing hepatectomy. They used (99m) Tc-mebrofinin HBS to quantify liver function before and after surgery and concluded that functional regeneration is already present at

  12. Regeneration in natural and logged tropical rain forest : modelling seed dispersal and regeneration

    NARCIS (Netherlands)

    Ulft, Lambertus Henricus van

    2004-01-01

    Regeneration and disturbance are thought to play key roles in the maintenance of the high tree species diversity in tropical rain forests. Nevertheless, the earliest stages in the regeneration of tropical rain forest trees, from seed production to established seedlings, have received little

  13. Applications of Metals for Bone Regeneration

    Directory of Open Access Journals (Sweden)

    Kristina Glenske

    2018-03-01

    Full Text Available The regeneration of bone tissue is the main purpose of most therapies in dental medicine. For bone regeneration, calcium phosphate (CaP-based substitute materials based on natural (allo- and xenografts and synthetic origins (alloplastic materials are applied for guiding the regeneration processes. The optimal bone substitute has to act as a substrate for bone ingrowth into a defect, as well as resorb in the time frame needed for complete regeneration up to the condition of restitution ad integrum. In this context, the modes of action of CaP-based substitute materials have been frequently investigated, where it has been shown that such materials strongly influence regenerative processes such as osteoblast growth or differentiation and also osteoclastic resorption due to different physicochemical properties of the materials. However, the material characteristics needed for the required ratio between new bone tissue formation and material degradation has not been found, until now. The addition of different substances such as collagen or growth factors and also of different cell types has already been tested but did not allow for sufficient or prompt application. Moreover, metals or metal ions are used differently as a basis or as supplement for different materials in the field of bone regeneration. Moreover, it has already been shown that different metal ions are integral components of bone tissue, playing functional roles in the physiological cellular environment as well as in the course of bone healing. The present review focuses on frequently used metals as integral parts of materials designed for bone regeneration, with the aim to provide an overview of currently existing knowledge about the effects of metals in the field of bone regeneration.

  14. Mechanisms of lymphatic regeneration after tissue transfer.

    Directory of Open Access Journals (Sweden)

    Alan Yan

    2011-02-01

    Full Text Available Lymphedema is the chronic swelling of an extremity that occurs commonly after lymph node resection for cancer treatment. Recent studies have demonstrated that transfer of healthy tissues can be used as a means of bypassing damaged lymphatics and ameliorating lymphedema. The purpose of these studies was to investigate the mechanisms that regulate lymphatic regeneration after tissue transfer.Nude mice (recipients underwent 2-mm tail skin excisions that were either left open or repaired with full-thickness skin grafts harvested from donor transgenic mice that expressed green fluorescent protein in all tissues or from LYVE-1 knockout mice. Lymphatic regeneration, expression of VEGF-C, macrophage infiltration, and potential for skin grafting to bypass damaged lymphatics were assessed.Skin grafts healed rapidly and restored lymphatic flow. Lymphatic regeneration occurred beginning at the peripheral edges of the graft, primarily from ingrowth of new lymphatic vessels originating from the recipient mouse. In addition, donor lymphatic vessels appeared to spontaneously re-anastomose with recipient vessels. Patterns of VEGF-C expression and macrophage infiltration were temporally and spatially associated with lymphatic regeneration. When compared to mice treated with excision only, there was a 4-fold decrease in tail volumes, 2.5-fold increase in lymphatic transport by lymphoscintigraphy, 40% decrease in dermal thickness, and 54% decrease in scar index in skin-grafted animals, indicating that tissue transfer could bypass damaged lymphatics and promote rapid lymphatic regeneration.Our studies suggest that lymphatic regeneration after tissue transfer occurs by ingrowth of lymphatic vessels and spontaneous re-connection of existing lymphatics. This process is temporally and spatially associated with VEGF-C expression and macrophage infiltration. Finally, tissue transfer can be used to bypass damaged lymphatics and promote rapid lymphatic regeneration.

  15. Avian Influenza: Myth or Mass Murder?

    Directory of Open Access Journals (Sweden)

    Carol Louie

    2005-01-01

    Full Text Available The purpose of the present article was to determine whether avian influenza (AI is capable of causing a pandemic. Using research from a variety of medical journals, books and texts, the present paper evaluates the probability of the AI virus becoming sufficiently virulent to pose a global threat. Previous influenza A pandemics from the past century are reviewed, focusing on the mortality rate and the qualities of the virus that distinguish it from other viruses. Each of the influenza A viruses reviewed were classified as pandemic because they met three key criteria: first, the viruses were highly pathogenic within the human population; second, the viruses were easily transmissible from person to person; and finally, the viruses were novel, such that a large proportion of the population was susceptible to infection. Information about the H5N1 subtype of AI has also been critically assessed. Evidence suggests that this AI subtype is both novel and highly pathogenic. The mortality rate from epidemics in Thailand in 2004 was as high as 66%. Clearly, this virus is aggressive. It causes a high death rate, proving that humans have a low immunity to the disease. To date, there has been little evidence to suggest that AI can spread among humans. There have been cases where the virus has transferred from birds to humans, in settings such as farms or open markets with live animal vending. If AI were to undergo a genetic reassortment that allowed itself to transmit easily from person to person, then a serious pandemic could ensue, resulting in high morbidity and mortality. Experts at the World Health Organization and the United States Centers for Disease Control and Prevention agree that AI has the potential to undergo an antigenic shift, thus triggering the next pandemic.

  16. Aerosolized avian influenza virus by laboratory manipulations

    Directory of Open Access Journals (Sweden)

    Li Zhiping

    2012-08-01

    Full Text Available Abstract Background Avian H5N1 influenza viruses present a challenge in the laboratory environment, as they are difficult to collect from the air due to their small size and relatively low concentration. In an effort to generate effective methods of H5N1 air removal and ensure the safety of laboratory personnel, this study was designed to investigate the characteristics of aerosolized H5N1 produced by laboratory manipulations during research studies. Results Normal laboratory procedures used to process the influenza virus were carried out independently and the amount of virus polluting the on-site atmosphere was measured. In particular, zootomy, grinding, centrifugation, pipetting, magnetic stirring, egg inoculation, and experimental zoogenetic infection were performed. In addition, common accidents associated with each process were simulated, including breaking glass containers, syringe injection of influenza virus solution, and rupturing of centrifuge tubes. A micro-cluster sampling ambient air pollution collection device was used to collect air samples. The collected viruses were tested for activity by measuring their ability to induce hemagglutination with chicken red blood cells and to propagate in chicken embryos after direct inoculation, the latter being detected by reverse-transcription PCR and HA test. The results showed that the air samples from the normal centrifugal group and the negative-control group were negative, while all other groups were positive for H5N1. Conclusions Our findings suggest that there are numerous sources of aerosols in laboratory operations involving H5N1. Thus, laboratory personnel should be aware of the exposure risk that accompanies routine procedures involved in H5N1 processing and take proactive measures to prevent accidental infection and decrease the risk of virus aerosol leakage beyond the laboratory.

  17. Aerosolized avian influenza virus by laboratory manipulations.

    Science.gov (United States)

    Li, Zhiping; Li, Jinsong; Zhang, Yandong; Li, Lin; Ma, Limin; Li, Dan; Gao, Feng; Xia, Zhiping

    2012-08-06

    Avian H5N1 influenza viruses present a challenge in the laboratory environment, as they are difficult to collect from the air due to their small size and relatively low concentration. In an effort to generate effective methods of H5N1 air removal and ensure the safety of laboratory personnel, this study was designed to investigate the characteristics of aerosolized H5N1 produced by laboratory manipulations during research studies. Normal laboratory procedures used to process the influenza virus were carried out independently and the amount of virus polluting the on-site atmosphere was measured. In particular, zootomy, grinding, centrifugation, pipetting, magnetic stirring, egg inoculation, and experimental zoogenetic infection were performed. In addition, common accidents associated with each process were simulated, including breaking glass containers, syringe injection of influenza virus solution, and rupturing of centrifuge tubes. A micro-cluster sampling ambient air pollution collection device was used to collect air samples. The collected viruses were tested for activity by measuring their ability to induce hemagglutination with chicken red blood cells and to propagate in chicken embryos after direct inoculation, the latter being detected by reverse-transcription PCR and HA test. The results showed that the air samples from the normal centrifugal group and the negative-control group were negative, while all other groups were positive for H5N1. Our findings suggest that there are numerous sources of aerosols in laboratory operations involving H5N1. Thus, laboratory personnel should be aware of the exposure risk that accompanies routine procedures involved in H5N1 processing and take proactive measures to prevent accidental infection and decrease the risk of virus aerosol leakage beyond the laboratory.

  18. Avian influenza in Chile: a successful experience.

    Science.gov (United States)

    Max, Vanessa; Herrera, José; Moreira, Rubén; Rojas, Hernán

    2007-03-01

    Avian influenza (AI) was diagnosed in May 2002 for the first time in Chile and South America. The epidemic was caused by the highly pathogenic AI (HPAI) virus subtype H7N3 that emerged from a low pathogenic virus. The index farm was a broiler breeder, located in San Antonio, V Region, which at the time was a densely populated poultry area. Stamping of 465,000 breeders, in 27 sheds, was immediately conducted. Surveillance activities detected a second outbreak, 1 wk later, at a turkey breeding farm from the same company. The second farm was located 4 km from the index case. Only 25% of the sheds were infected, and 18,500 turkeys were destroyed. In both outbreaks, surveillance zones and across-country control measures were established: prediagnosis quarantine, depopulation, intensive surveillance, movement control, and increased biosecurity. Other measures included cleaning, disinfection, and controlling the farms with sentinels to detect the potential presence of the virus. Zoning procedures were implemented to allow the international trade of poultry products from unaffected areas. Positive serologic results to H5N2 virus also were detected in other poultry farms, but there was no evidence of clinical signs or virus isolation. Epidemiological investigation and laboratory confirmation determined that positive serology was related to a contaminated imported batch of vaccine against inclusion body hepatitis. All actions taken allowed the control of the epidemic, and within 7 mo, Chile was free of AI. Epidemic and control measures that prevented further spread are described in this article, which illustrates the importance of a combination of control measures during and after an outbreak of AI. This study is a good example of how veterinary services need to respond if their country is affected by HPAI.

  19. Lens regeneration in axolotl: new evidence of developmental plasticity

    Directory of Open Access Journals (Sweden)

    Suetsugu-Maki Rinako

    2012-12-01

    Full Text Available Abstract Background Among vertebrates lens regeneration is most pronounced in newts, which have the ability to regenerate the entire lens throughout their lives. Regeneration occurs from the dorsal iris by transdifferentiation of the pigment epithelial cells. Interestingly, the ventral iris never contributes to regeneration. Frogs have limited lens regeneration capacity elicited from the cornea during pre-metamorphic stages. The axolotl is another salamander which, like the newt, regenerates its limbs or its tail with the spinal cord, but up until now all reports have shown that it does not regenerate the lens. Results Here we present a detailed analysis during different stages of axolotl development, and we show that despite previous beliefs the axolotl does regenerate the lens, however, only during a limited time after hatching. We have found that starting at stage 44 (forelimb bud stage lens regeneration is possible for nearly two weeks. Regeneration occurs from the iris but, in contrast to the newt, regeneration can be elicited from either the dorsal or the ventral iris and, occasionally, even from both in the same eye. Similar studies in the zebra fish concluded that lens regeneration is not possible. Conclusions Regeneration of the lens is possible in the axolotl, but differs from both frogs and newts. Thus the axolotl iris provides a novel and more plastic strategy for lens regeneration.

  20. Biological regeneration of para-nitrophenol loaded activated carbon

    International Nuclear Information System (INIS)

    Durrani, M.A.Q.; Martin, R.J.

    1997-01-01

    Biological regeneration is one of several methods that may be used to restore the adsorptive capacity of exhausted granular activated carbon (GAC). This study deals with in-situ biological regeneration on a pilot scale. The principal objective of this research was to ascertain whether biological regeneration of GAC could occur under conditions typical of water treatment. The important parameters which may have the greatest impact on bio regeneration of a given adsorbate were studied. The research investigated the extent of bio regeneration for para-nitrophenol (PNP) of concentration 50 mg/L. Bio regeneration in the total exhaustion system was evaluated in terms of regeneration efficiency and the substrate removal. A three mode procedure was followed for each bio regeneration run. The prepared carbon was initially exhausted with an adsorbate; it was then bio regenerated for para-nitrophenol (PNP) of concentration 50 mg/L. Bio regeneration in he total exhaustion system was evaluated in terms of regeneration efficiency and the substrate removal. A three mode procedure was followed for each bio regeneration run. The prepared carbon was initially exhausted with an adsorbate; it was then bio regenerated with a mixed culture of bacteria, and lastly the carbon was re-saturated. In the totally exhausted GAC system, the bio regeneration was enhanced by increasing the during of regeneration for a fixed initial biomass content of the bioreactor. The bio regeneration efficiency of the totally exhausted (with PNP) GAC the empty bed contact time (EBCT) and the initial concentration of the substrate had a profound effect on the bio regeneration efficiency. Bacterial counts in the effluents of regenerated GAC columns were significantly more than those of fresh carbon effluents. (author)

  1. Thinning in artificially regenerated young beech stands

    Directory of Open Access Journals (Sweden)

    Novák Jiří

    2015-12-01

    Full Text Available Although beech stands are usually regenerated naturally, an area of up to 5,000 ha year−1 is artificially regenerated by beech in the Czech Republic annually. Unfortunately, these stands often showed insufficient stand density and, consequently, lower quality of stems. Therefore, thinning methods developed for naturally regenerated beech stands are applicable with difficulties. The paper evaluates the data from two thinning experiments established in young artificially regenerated beech stands located in different growing conditions. In both experiments, thinning resulted in the lower amount of salvage cut in following years. Positive effect of thinning on periodic stand basal area increment and on periodic diameter increment of dominant trees was found in the beech stand located at middle elevations. On the other hand, thinning effects in mountain conditions were negligible. Thinning focusing on future stand quality cannot be commonly applied in artificially regenerated beech stands because of their worse initial quality and lower density. However, these stands show good growth and response to thinning, hence their management can be focused on maximising beech wood production.

  2. Redox Control of Skeletal Muscle Regeneration.

    Science.gov (United States)

    Le Moal, Emmeran; Pialoux, Vincent; Juban, Gaëtan; Groussard, Carole; Zouhal, Hassane; Chazaud, Bénédicte; Mounier, Rémi

    2017-08-10

    Skeletal muscle shows high plasticity in response to external demand. Moreover, adult skeletal muscle is capable of complete regeneration after injury, due to the properties of muscle stem cells (MuSCs), the satellite cells, which follow a tightly regulated myogenic program to generate both new myofibers and new MuSCs for further needs. Although reactive oxygen species (ROS) and reactive nitrogen species (RNS) have long been associated with skeletal muscle physiology, their implication in the cell and molecular processes at work during muscle regeneration is more recent. This review focuses on redox regulation during skeletal muscle regeneration. An overview of the basics of ROS/RNS and antioxidant chemistry and biology occurring in skeletal muscle is first provided. Then, the comprehensive knowledge on redox regulation of MuSCs and their surrounding cell partners (macrophages, endothelial cells) during skeletal muscle regeneration is presented in normal muscle and in specific physiological (exercise-induced muscle damage, aging) and pathological (muscular dystrophies) contexts. Recent advances in the comprehension of these processes has led to the development of therapeutic assays using antioxidant supplementation, which result in inconsistent efficiency, underlying the need for new tools that are aimed at precisely deciphering and targeting ROS networks. This review should provide an overall insight of the redox regulation of skeletal muscle regeneration while highlighting the limits of the use of nonspecific antioxidants to improve muscle function. Antioxid. Redox Signal. 27, 276-310.

  3. Method of continuously regenerating decontaminating electrolytic solution

    International Nuclear Information System (INIS)

    Sasaki, Takashi; Kobayashi, Toshio; Wada, Koichi.

    1985-01-01

    Purpose: To continuously recover radioactive metal ions from the electrolytic solution used for the electrolytic decontamination of radioactive equipment and increased with the radioactive dose, as well as regenerate the electrolytic solution to a high concentration acid. Method: A liquid in an auxiliary tank is recycled to a cathode chamber containing water of an electro depositing regeneration tank to render pH = 2 by way of a pH controller and a pH electrode. The electrolytic solution in an electrolytic decontaminating tank is introduced by way of an injection pump to an auxiliary tank and, interlocking therewith, a regenerating solution is introduced from a regenerating solution extracting pump by way of a extraction pipeway to an electrolytic decontaminating tank. Meanwhile, electric current is supplied to the electrode to deposit radioactive metal ions dissolved in the cathode chamber on the capturing electrode. While on the other hand, anions are transferred by way of a partition wall to an anode chamber to regenerate the electrolytic solution to high concentration acid solution. While on the other hand, water is supplied by way of an electromagnetic valve interlocking with the level meter to maintain the level meter constant. This can decrease the generation of the liquid wastes and also reduce the amount of the radioactive secondary wastes. (Horiuchi, T.)

  4. Avian Pox in Native Captive Psittacines, Brazil, 2015.

    Science.gov (United States)

    Esteves, Felipe C B; Marín, Sandra Y; Resende, Maurício; Silva, Aila S G; Coelho, Hannah L G; Barbosa, Mayara B; D'Aparecida, Natália S; de Resende, José S; Torres, Ana C D; Martins, Nelson R S

    2017-01-01

    To investigate an outbreak of avian pox in psittacines in a conservation facility, we examined 94 birds of 10 psittacine species, including sick and healthy birds. We found psittacine pox virus in 23 of 27 sick birds and 4 of 67 healthy birds. Further characterization is needed for these isolates.

  5. A nine - year retrospective study of avian neoplastic diseases in ...

    African Journals Online (AJOL)

    Avian neoplastic diseases have been identified as one of the leading causes of mortality and production losses in commercial chickens in Nigeria. Although available reports described the trend of Marek's disease in Zaria, Kaduna state, they did not take cognizance of other neoplastic diseases of poultry hence the need for ...

  6. Serological and Virological Study of Newcastle Disease and Avian ...

    African Journals Online (AJOL)

    Serological survey on the prevalence of Newcastle disease (NCD) virus antibodies using haemagglutination inhibition test (HI) and virological detection by RT-PCR of highly pathogenic avian influenza (HPAI) H5N1, were carried out in 6 regions of Senegal from June to November 2008. Rural chickens were raised in free ...

  7. Perspectives on avian and bovine leukemia virus immunological studies

    International Nuclear Information System (INIS)

    Higuchi, T.; Souza, J.M.M. de; Nogueira, Z.M.; Ogata, H.

    1984-01-01

    The avian and bovine RNA virus are studied. The mechanism of replication, the genome, the ultrastructural composition, the immunogens reactivity, the class of determinants and affinity are presented. Purification techniques of viral proteins and immunoassay proceeding are reported. (M.A.C.) [pt

  8. Free-grazing ducks and highly pathogenic avian influenza, Thailand

    NARCIS (Netherlands)

    Gilbert, Marius; Chaitaweesup, P.; Parakamawongsa, T.; Premashthira, S.; Tiensin, T.; Kalpravidh, W.; Wagner, H.; Slingenbergh, J.

    Thailand has recently had 3 epidemic waves of highly pathogenic avian influenza (HPAI); virus was again detected in July 2005. Risk factors need to be identified to better understand disease ecology and assist HPAI surveillance and detection. This study analyzed the spatial distribution of HPAI

  9. Investigating maternal hormones in avian eggs : Measurement, manipulation, and interpretation

    NARCIS (Netherlands)

    Groothuis, TGG; Von Engelhardt, N; Bauchinger, U; Goymann, W; JenniEiermann, S

    2005-01-01

    The last decade has witnessed a surge in studies on steroid hormones of maternal origin present in avian eggs and affecting offspring development. The value of such studies for the understanding of maternal effects and individual differentiation is endorsed and a series of methodological and

  10. Developmental imaging: the avian embryo hatches to the challenge.

    Science.gov (United States)

    Kulesa, Paul M; McKinney, Mary C; McLennan, Rebecca

    2013-06-01

    The avian embryo provides a multifaceted model to study developmental mechanisms because of its accessibility to microsurgery, fluorescence cell labeling, in vivo imaging, and molecular manipulation. Early two-dimensional planar growth of the avian embryo mimics human development and provides unique access to complex cell migration patterns using light microscopy. Later developmental events continue to permit access to both light and other imaging modalities, making the avian embryo an excellent model for developmental imaging. For example, significant insights into cell and tissue behaviors within the primitive streak, craniofacial region, and cardiovascular and peripheral nervous systems have come from avian embryo studies. In this review, we provide an update to recent advances in embryo and tissue slice culture and imaging, fluorescence cell labeling, and gene profiling. We focus on how technical advances in the chick and quail provide a clearer understanding of how embryonic cell dynamics are beautifully choreographed in space and time to sculpt cells into functioning structures. We summarize how these technical advances help us to better understand basic developmental mechanisms that may lead to clinical research into human birth defects and tissue repair. Copyright © 2013 Wiley Periodicals, Inc.

  11. Avian Influenza in wild birds from Chile, 2007-2009.

    Science.gov (United States)

    Mathieu, Christian; Moreno, Valentina; Pedersen, Janice; Jeria, Julissa; Agredo, Michel; Gutiérrez, Cristian; García, Alfonso; Vásquez, Marcela; Avalos, Patricia; Retamal, Patricio

    2015-03-02

    Aquatic and migratory birds, the main reservoir hosts of avian influenza viruses including those with high pathogenic potential, are the wildlife species with the highest risk for viral dissemination across countries and continents. In 2002, the Chilean poultry industry was affected with a highly pathogenic avian influenza strain, which created economic loss and triggered the establishment of a surveillance program in wild birds. This effort consisted of periodic samplings of sick or suspicious animals found along the coast and analyses with standardized techniques for detection of influenza A virus. The aim of this work is to report the detection of three avian influenza strains (H13N2, H5N9, H13N9) in gulls from Chile between 2007-2009, which nucleotide sequences showed highest similitudes to viruses detected in wild birds from North America. These results suggest a dissemination route for influenza viruses along the coasts of Americas. Migratory and synanthropic behaviors of birds included in this study support continued monitoring of avian influenza viruses isolated from wild birds in The Americas and the establishment of biosecurity practices in farms. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Evaluation of antibody response in mice against avian influenza A

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences; Volume 39; Issue 3. Evaluation of antibody response in mice against avian influenza A (H5N1) strain neuraminidase expressed in yeast Pichia pastoris. Murugan Subathra Ponsekaran Santhakumar Mangamoori Lakshmi Narasu Syed Sultan Beevi Sunil K Lal. Articles Volume 39 ...

  13. Molecular diversity of avian schistosomes in Danish freshwater snails

    DEFF Research Database (Denmark)

    Christiansen, Anne Ø.; Olsen, Annette; Buchmann, Kurt

    2016-01-01

    Avian schistosomes are widespread parasites of snails and waterfowl and may cause cercarial dermatitis (swimmer's itch) in humans, a disease that is frequently reported in European countries. These parasites are known to occur in Denmark, but here, we applied a new approach using molecular tools ...

  14. Avian Bornavirus in Free-Ranging Psittacine Birds, Brazil

    Science.gov (United States)

    Encinas-Nagel, Nuri; Enderlein, Dirk; Piepenbring, Anne; Herden, Christiane; Heffels-Redmann, Ursula; Felippe, Paulo A.N.; Arns, Clarice; Hafez, Hafez M.

    2014-01-01

    Avian bornavirus (ABV) has been identified as the cause of proventricular dilatation disease in birds, but the virus is also found in healthy birds. Most studies of ABV have focused on captive birds. We investigated 86 free-ranging psittacine birds in Brazil and found evidence for natural, long-term ABV infection. PMID:25417715

  15. Optimizing factors influencing DNA extraction from fresh whole avian ...

    African Journals Online (AJOL)

    A study was conducted to optimize the efficient combination of lysis buffer, proteinase K, incubation time, phenol-chloroform-isoamyl alcohol (PCI) volume, spinning rate (rpm), and precipitation agent on quantity and quality of DNA extracted from various volumes of avian blood. Blood samples were collected in EDTA and ...

  16. Classical Swine Fever and Avian Influenza epidemcis: Lessons learned

    NARCIS (Netherlands)

    Elbers, A.R.; Loeffen, W.L.A.; Koch, G.

    2012-01-01

    This publication is based on a talk which was held in the course of the spring symposium „Impfen statt Keulen“ of the Akademie für Tiergesundheit (AfT) 2011 in Wiesbaden-Naurod. Experience with recent large-scale epidemics of Classical Swine Fever and Avian Influenza – among others in the

  17. Seroprevalence of Selected Avian Pathogens of Backyard Poultry in ...

    African Journals Online (AJOL)

    A serological survey for Newcastle (ND), avian influenza (AI), Gumboro (IBD) and Infectious bronchitis (IB) viruses was conducted in 310 serum samples in village chickens in Sinar State, Sudan. The studied chickens had no history of previous vaccination and showed no clinical signs. Results of indirect enzyme-linked ...

  18. Review of highly pathogenic avian influenza outbreaks in poultry in ...

    African Journals Online (AJOL)

    All the confirmed highly pathogenic avian influenza cases that were diagnosed in Zaria at the Veterinary Teaching Hospital, Ahmadu Bello University, Zaria, Nigeria, were reviewed in this study. The outbreaks occurred between the months of December, 2006 and March, 2007. The clinical signs and postmortem lesions ...

  19. The epizootiology of the highly pathogenic avian influenza prior to ...

    African Journals Online (AJOL)

    The epizootiology of the highly pathogenic avian influenza prior to the anticipated pandemic of the early twenty first century. ... Transmission of highly pathogenic H5N1 from domestic fowls back to migratory waterfowl in western China has increased the geographic spread. This has grave consequences for the poultry ...

  20. Avian Influenza in Migratory Birds : Regional Surveillance and ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Outbreaks may only occur after transmission from migratory species to domestic flocks through local amplification and secondary spread through the movement of poultry or people, as well as equipment or vehicles contaminated by sick birds. The Asia Partnership for Avian Influenza Research (APAIR) brings together ...

  1. Asian Partnership for Avian Influenza Research : Effectiveness of ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... Indonesia, Thailand and Viet Nam for collaboration on research and research capacity building in avian influenza prevention and control. This grant will allow APAIR to investigate the effectiveness of the measures employed by China, Thailand and Viet Nam and evaluate the factors contributing to their success or failure.

  2. Antimicrobial susceptibilities of avian Escherichia coli isolates in ...

    African Journals Online (AJOL)

    Colibacillosis is a poultry disease of economic importance in Iran and all around the world. The aim of this study is to test the antibiotic sensitivity of Escherichia coli strains which were isolated in Tabriz. A total of 100 E. coli strains isolated from avian colibacillosis of 50 farms from 2008 to 2009 in Tabriz, were investigated for ...

  3. Cell culture based production of avian influenza vaccines

    NARCIS (Netherlands)

    Wielink, van R.

    2012-01-01

    Vaccination of poultry can be used as a tool to control outbreaks of avian influenza, including that of highly pathogenic H5 and H7 strains. Influenza vaccines are traditionally produced in embryonated chicken eggs. Continuous cell lines have been suggested as an alternative substrate to produce

  4. Rapidly expanding range of highly pathogenic avian influenza viruses

    Science.gov (United States)

    Hall, Jeffrey S.; Dusek, Robert J.; Spackman, Erica

    2015-01-01

    The movement of highly pathogenic avian influenza (H5N8) virus across Eurasia and into North America and the virus’ propensity to reassort with co-circulating low pathogenicity viruses raise concerns among poultry producers, wildlife biologists, aviculturists, and public health personnel worldwide. Surveillance, modeling, and experimental research will provide the knowledge required for intelligent policy and management decisions.

  5. Avian Mobbing of the Puerto Rican Boa (Epicrates inornatus)

    Science.gov (United States)

    JAVIER E. MERCADO; ESTEBAN TERRANOVA; JR. WUNDERLE

    2002-01-01

    Mobbing, defined as an intense collective behavior in which birds of one or more species scold or even physically attack a predator, is known from a variety of bird species (Campbell and Lack, 1985; Gill, 1995). Targets commonly include hawks, owls, and snakes. In the West Indies, observations have documented avian mobbing towards various hawk species (e.g., Jeffrey-...

  6. Low frequency of paleoviral infiltration across the avian phylogeny

    DEFF Research Database (Denmark)

    Cui, Jie; Zhao, Wei; Huang, Zhiyong

    2014-01-01

    Background: Mammalian genomes commonly harbor endogenous viral elements. Due to a lack of comparable genome-scale sequence data, far less is known about endogenous viral elements in avian species, even though their small genomes may enable important insights into the patterns and processes of end...

  7. Detection of antibodies to avian influenza, infectious bronchitis and ...

    African Journals Online (AJOL)

    Detection of antibodies to avian influenza, infectious bronchitis and Newcastle disease viruses in wild birds in three states of Nigeria. ... The PDF file you selected should load here if your Web browser has a PDF reader plug-in installed (for example, a recent version of Adobe Acrobat Reader). If you would like more ...

  8. H9N2 avian influenza transmission and antigenicity

    Science.gov (United States)

    Low pathogenic H9N2 avian influenza has become endemic in parts of Asia, the Middle East and North Africa causing respiratory disease with occasional mortality. The use of vaccination has become common to try and control the clinical disease, but vaccination has not been shown to be an effective er...

  9. Pathogenicity of highly pathogenic avian influenza virus in mammals

    NARCIS (Netherlands)

    de Wit, Emmie; Kawaoka, Yoshihiro; de Jong, Menno D.; Fouchier, Ron A. M.

    2008-01-01

    In recent years, there has been an increase in outbreaks of highly pathogenic avian influenza (HPAI) in poultry. Occasionally, these outbreaks have resulted in transmission of influenza viruses to humans and other mammals, with symptoms ranging from conjunctivitis to pneumonia and death. Here, the

  10. Transmission of highly pathogenic avian influenza H7 virus

    NARCIS (Netherlands)

    Bos, M.E.H.

    2009-01-01

    Knowledge of the transmission of highly pathogenic avian influenza (HPAI) virus still has gaps, complicating epidemic control. A model was developed to back-calculate the day HPAI virus was introduced into a flock, based on within-flock mortality data of the Dutch HPAI H7N7 epidemic (2003). The

  11. First characterization of avian influenza viruses from Greenland 2014

    DEFF Research Database (Denmark)

    Hartby, Christina Marie; Krog, Jesper Schak; Ravn Merkel, Flemming

    2016-01-01

    In late February 2014, unusually high numbers of wild birds, thick-billed murre (Uria lomvia), were found dead at the coast of South Greenland. To investigate the cause of death, 45 birds were submitted for laboratory examinations in Denmark. Avian influenza viruses (AIVs) with subtypes H11N2...

  12. Avian Metapneumovirus Molecular Biology and Development of Genetically Engineered Vaccines

    Science.gov (United States)

    Avian metapneumovirus (aMPV) is an economically important pathogen of turkeys with a worldwide distribution. aMPV is a member of the genus Metapneumovirus within the subfamily Pneumovirinae of the family Paramyxoviridae. The genome of aMPV is a non-segmented, single-stranded, negative-sense RNA of 1...

  13. The evaluation of domestic ducks as potential reservoir of avian ...

    African Journals Online (AJOL)

    The evaluation of domestic ducks as potential reservoir of avian influenza virus in post HPAI H5N1 outbreak area, Sunyani Municipality, Brong Ahafo Region of Ghana. Vitus Burimuah, W.K. Ampofo, B Awumbila, N Yebuah, B.O. Emikpe, W Tasiame, R.D. Folitse ...

  14. Avian Influenza A (H7N9) Virus

    Science.gov (United States)

    ... August 7, 2017 Increase in Human Infections with Avian Influenza A(H7N9) Virus During the Fifth Epidemic — China, October 2016–February 2017 Antigenic and genetic characteristics of zoonotic influenza viruses and candidate vaccine viruses developed for ...

  15. Surveillance of wild birds for avian influenza virus

    NARCIS (Netherlands)

    Hoye, B.J.; Munster, V.J.; Nishiura, H.; Klaassen, M.R.J.; Fouchier, R.A.M

    2010-01-01

    Recent demand for increased understanding of avian infl uenza virus in its natural hosts, together with the development of high-throughput diagnostics, has heralded a new era in wildlife disease surveillance. However, survey design, sampling, and interpretation in the context of host populations

  16. Avian influenza: the political economy of disease control in Cambodia.

    Science.gov (United States)

    Ear, Sophal

    2011-01-01

    Abstract In the wake of avian flu outbreaks in 2004, Cambodia received $45 million in commitments from international donors to help combat the spread of animal and human influenza, particularly avian influenza (H5N1). How countries leverage foreign aid to address the specific needs of donors and the endemic needs of the nation is a complex and nuanced issue throughout the developing world. Cambodia is a particularly compelling study in pandemic preparedness and the management of avian influenza because of its multilayered network of competing local, national, and global needs, and because the level of aid in Cambodia represents approximately $2.65 million per human case-a disproportionately high number when compared with neighbors Vietnam and Indonesia. This paper examines how the Cambodian government has made use of animal and human influenza funds to protect (or fail to protect) its citizens and the global community. It asks how effective donor and government responses were to combating avian influenza in Cambodia, and what improvements could be made at the local and international level to help prepare for and respond to future outbreaks. Based on original interviews, a field survey of policy stakeholders, and detailed examination of Cambodia's health infrastructure and policies, the findings illustrate that while pandemic preparedness has shown improvements since 2004, new outbreaks and human fatalities accelerated in 2011, and more work needs to be done to align the specific goals of funders with the endemic needs of developing nations.

  17. Avian Influenza Risk : Characterization and Dynamics of Backyard ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    The highly pathogenic avian influenza (HPAI) virus H5N1 produces severe disease and high mortality in domestic poultry, waterfowl and other bird species. Public health authorities are concerned that this strain may mutate to became contagious between people. Throughout Southeast Asia and China, farmers raise poultry ...

  18. Planning and Implementation of Urban Regeneration

    DEFF Research Database (Denmark)

    Aunsborg, Christian; Sørensen, Michael Tophøj

    2008-01-01

    new statutory tools to handle the spatial transformation of urban regeneration areas. The paper examines the subsequent development of Danish planning legislation with the purpose of determining whether the present 'statutory toolbox' can be considered sufficient compared to the problems...... the regeneration challenge became an issue in the professional debate. The urban, economic and spatial problematics rising from structural development trends of society were subject to a committee work from 1999 through 2001. The work resulted in a number of recommendations comprising i.a. suggestions concerning...... and challenges emerging in practice. To evaluate the adequacy of the toolbox the paper draws on case studies on urban regeneration projects in three major Danish cities. The conclusion is that the legislative developments during the last five years must be considered very relevant to problem solving in practice...

  19. Demagnetizing fields in active magnetic regenerators

    DEFF Research Database (Denmark)

    Nielsen, Kaspar Kirstein; Bahl, Christian R.H.; Smith, Anders

    2014-01-01

    A magnetic material in an externally applied magnetic field will in general experience a spatially varying internal magnetic field due to demagnetizing effects. When the performance of active magnetic regenerators (AMRs) is evaluated using numerical models the internal field is often assumed...... is in general both a function of the overall shape of the regenerator and its morphology (packed particles, parallel plates etc.) as well as the magnetization of the material. Due to the pronounced temperature dependence of the magnetization near the Curie temperature, the demagnetization field is also...... temperature dependent. We propose a relatively straightforward method to correct sufficiently for the demagnetizing field in AMR models. We discuss how the demagnetizing field behaves in regenerators made of packed spheres under realistic operation conditions....

  20. Comparative genomic data of the Avian Phylogenomics Project.

    Science.gov (United States)

    Zhang, Guojie; Li, Bo; Li, Cai; Gilbert, M Thomas P; Jarvis, Erich D; Wang, Jun

    2014-01-01

    The evolutionary relationships of modern birds are among the most challenging to understand in systematic biology and have been debated for centuries. To address this challenge, we assembled or collected the genomes of 48 avian species spanning most orders of birds, including all Neognathae and two of the five Palaeognathae orders, and used the genomes to construct a genome-scale avian phylogenetic tree and perform comparative genomics analyses (Jarvis et al. in press; Zhang et al. in press). Here we release assemblies and datasets associated with the comparative genome analyses, which include 38 newly sequenced avian genomes plus previously released or simultaneously released genomes of Chicken, Zebra finch, Turkey, Pigeon, Peregrine falcon, Duck, Budgerigar, Adelie penguin, Emperor penguin and the Medium Ground Finch. We hope that this resource will serve future efforts in phylogenomics and comparative genomics. The 38 bird genomes were sequenced using the Illumina HiSeq 2000 platform and assembled using a whole genome shotgun strategy. The 48 genomes were categorized into two groups according to the N50 scaffold size of the assemblies: a high depth group comprising 23 species sequenced at high coverage (>50X) with multiple insert size libraries resulting in N50 scaffold sizes greater than 1 Mb (except the White-throated Tinamou and Bald Eagle); and a low depth group comprising 25 species sequenced at a low coverage (~30X) with two insert size libraries resulting in an average N50 scaffold size of about 50 kb. Repetitive elements comprised 4%-22% of the bird genomes. The assembled scaffolds allowed the homology-based annotation of 13,000 ~ 17000 protein coding genes in each avian genome relative to chicken, zebra finch and human, as well as comparative and sequence conservation analyses. Here we release full genome assemblies of 38 newly sequenced avian species, link genome assembly downloads for the 7 of the remaining 10 species, and provide a guideline of