Sample records for 4-fold degenerate sites

  1. A clustering property of highly-degenerate transcription factor binding sites in the mammalian genome

    PubMed Central

    Zhang, Chaolin; Xuan, Zhenyu; Otto, Stefanie; Hover, John R.; McCorkle, Sean R.; Mandel, Gail; Zhang, Michael Q.

    2006-01-01

    Transcription factor binding sites (TFBSs) are short DNA sequences interacting with transcription factors (TFs), which regulate gene expression. Due to the relatively short length of such binding sites, it is largely unclear how the specificity of protein–DNA interaction is achieved. Here, we have performed a genome-wide analysis of TFBS-like sequences for the transcriptional repressor, RE1 Silencing Transcription Factor (REST), as well as for several other representative mammalian TFs (c-myc, p53, HNF-1 and CREB). We find a nonrandom distribution of inexact sites for these TFs, referred to as highly-degenerate TFBSs, that are enriched around the cognate binding sites. Comparisons among human, mouse and rat orthologous promoters reveal that these highly-degenerate sites are conserved significantly more than expected by random chance, suggesting their positive selection during evolution. We propose that this arrangement provides a favorable genomic landscape for functional target site selection. PMID:16670430

  2. Chondrocyte clusters adjacent to sites of cartilage degeneration have characteristics of progenitor cells.

    PubMed

    Hoshiyama, Yoshiaki; Otsuki, Shuhei; Oda, Shuhei; Kurokawa, Yoshitaka; Nakajima, Mikio; Jotoku, Tsuyoshi; Tamura, Ryuichi; Okamoto, Yoshinori; Lotz, Martin K; Neo, Masashi

    2015-04-01

    The purpose of this study was to investigate the site-specific characteristics and roles of chondrocyte clusters in human knee osteoarthritis. Cartilage explants were obtained from 45 knees undergoing total knee replacement surgery. The explants were taken from 4 locations in the knee: the medial femoral condyle, the medial posterior femoral condyle (MPC), the lateral femoral condyle, and the lateral posterior femoral condyle (LPC). Cartilage degeneration, cell density, and cell arrangement were compared histologically. A live/dead cell viability assay and immunohistochemical analyses using antibodies against STRO-1, FGF2, and Ki-67 were performed. Cell proliferation and cartilaginous nodule production in MPC and LPC explants in monolayer culture were compared. Finally, MPC cartilage explants were cultured to observe histological changes. The cell density of the MPC explants was higher than that of the LPC because of clustering. MPC explants contained more live cells than the LPC did, and the expression of IHC markers in MPC explants was higher than that in LPC. Chondrocytes from MPC proliferated faster and produced more nodules in monolayer culture than those from the LPC and MPC explants were repaired during organ culture. In conclusion, chondrocyte clusters adjacent to severe cartilage degeneration have specific characteristics, with progenitor and proliferative potential. PMID:25691232

  3. Enumerative Geometry of Calabi-Yau 4-Folds

    Microsoft Academic Search

    A. Klemm; R. Pandharipande

    2008-01-01

    Gromov-Witten theory is used to define an enumerative geometry of curves in Calabi-Yau 4-folds. The main technique is to find\\u000a exact solutions to moving multiple cover integrals. The resulting invariants are analogous to the BPS counts of Gopakumar\\u000a and Vafa for Calabi-Yau 3-folds. We conjecture the 4-fold invariants to be integers and expect a sheaf theoretic explanation.\\u000a \\u000a Several local Calabi-Yau

  4. Biorthogonal Wavelets with 4-fold Axial Symmetry for Quadrilateral Surface Multiresolution Processing

    E-print Network

    Jiang, Qingtang

    Biorthogonal Wavelets with 4-fold Axial Symmetry for Quadrilateral Surface Multiresolution Processing Qingtang Jiang Abstract Surface multiresolution processing is an important subject in CAGD. It also poses many challenging problems including the design of multiresolution algorithms. Unlike images

  5. The Existence of a Smooth Divisor on Fano 4-FOLDS of INDEX 2

    NASA Astrophysics Data System (ADS)

    Prokhorov, Yu G.

    1995-02-01

    Let X be a smooth Fano 4-fold of index 2, and H a fundamental divisor on X, that is, an ample divisor such that K_X=2H. It is proved that there is a smooth irreducible element in the linear system \\vert H\\vert.Bibliography: 23 titles.

  6. Cerebellar Degeneration

    MedlinePLUS

    ... in which cerebellar degeneration is a key feature Friedreich’s ataxia, and other spinocerebellar ataxias, which are caused by ... Tel: 763-553-0020 Fax: 763-553-0167 Friedreich's Ataxia Research Alliance (FARA) P.O. Box 1537 Springfield, ...

  7. Phosphoproteomic analysis reveals site-specific changes in GFAP and NDRG2 phosphorylation in frontotemporal lobar degeneration

    PubMed Central

    Herskowitz, Jeremy H.; Seyfried, Nicholas T.; Duong, Duc M.; Xia, Qiangwei; Rees, Howard D.; Gearing, Marla; Peng, Junmin; Lah, James J.; Levey, Allan I.

    2010-01-01

    Frontotemporal lobar degeneration (FTLD) is a progressive neurodegenerative disease characterized by behavioral abnormalities, personality changes, language dysfunction, and can co-occur with the development of motor neuron disease. One major pathological form of FTLD is characterized by intracellular deposition of ubiquitinated and phosphorylated TAR DNA binding protein-43 (TDP-43), suggesting that dysregulation in phosphorylation events may contribute to disease progression. However, to date systematic analysis of the phosphoproteome in FTLD brains has not been reported. In this study we employed immobilized metal affinity chromatography (IMAC) followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify phosphopeptides from FTLD and age-matched control postmortem human brain tissue. Using this approach we identified 786 phosphopeptides in frontal cortex (control and FTLD), in which the population of phosphopeptides represented approximately 50% of the total peptides analyzed. Label free quantification using spectral counts revealed six proteins with significant changes in the FTLD phosphoproteome. N-myc-downstream regulated gene 2 (NDRG2) and glial fibrillary acidic protein (GFAP) had an increased number of phosphospectra in FTLD, whereas microtubule associated protein 1A (MAP1A), reticulon 4 (RTN4; also referred to as neurite outgrowth inhibitor (Nogo)), protein kinase C gamma (PRKCG), and heat shock protein 90kDa alpha, class A member 1(HSP90AA1) had significantly fewer phosphospectra compared to control brain. To validate these differences, we examined NDRG2 phosphorylation in FTLD brain by immunoblot analyses, and using a phosphoserine-13 (pSer13) GFAP monoclonal antibody we show an increase in pSer13 GFAP levels by immunoblot concomitant with increased overall GFAP levels in FTLD cases. These data highlight the utility of combining proteomic and phosphoproteomic strategies to characterize postmortem human brain tissue. PMID:20886841

  8. Macular Degeneration

    NSDL National Science Digital Library

    Patient Education Institute

    This patient education program discusses age-related macular degeneration including the causes, risks, symptoms, diagnosis, treatment options, and management of the disease. It also reviews the anatomy of the eye and vision. This resource is a MedlinePlus Interactive Health Tutorial from the National Library of Medicine, designed and developed by the Patient Education Institute. NOTE: This tutorial requires a special Flash plug-in, version 4 or above. If you do not have Flash, you will be prompted to obtain a free download of the software before you start the tutorial. You will also need an Acrobat Reader, available as a free download, in order to view the Reference Summary.

  9. Crystalline structures of polymeric hydrocarbon with 3,4-fold helical chains

    NASA Astrophysics Data System (ADS)

    Lian, Chao-Sheng; Li, Han-Dong; Wang, Jian-Tao

    2015-01-01

    Molecular hydrocarbons are well-known to polymerize under pressure to form covalently bonded frameworks. Here we predict by ab initio calculations two distinct three-dimensional hydrocarbon crystalline structures composed of 3-fold and 4-fold helical CH chains in rhombohedral () and tetragonal (I41/a) symmetry, respectively. Both structures with 1:1 stoichiometry are found to be energetically more favorable than solid acetylene and cubane, and even more stable than benzene II solid at high pressure. The calculations on vibrational, electronic, and optical properties reveal that the new chiral hydrocarbons are dynamically stable with large bulk moduli around 200 GPa, and exhibit a transparent insulating behavior with indirect band gaps of 5.9 ~ 6.7 eV and anisotropic adsorption spectra. Such forms of hydrocarbon, once synthesized, would have wide applications in mechanical, optoelectronic, and biological materials.

  10. Precision half-life measurement of the 4-fold forbidden {beta} decay of {sup 50}V

    SciTech Connect

    Dombrowski, H.; Neumaier, S. [Physikalisch-Technische Bundesanstalt (PTB), D-38116 Braunschweig (Germany); Zuber, K. [Institut fuer Kern- und Teilchenphysik, Technische Universitaet Dresden, D-01069 Dresden (Germany)

    2011-05-15

    A sensitive search of the 4-fold forbidden nonunique decay of {sup 50}V has been performed. A total mass measuring time product of 186 kg d has been accumulated. A reliable half-life value with the highest precision so far of (2.29{+-}0.25)x10{sup 17} years of the electron capture decay of {sup 50}V into the first excited state of {sup 50}Ti could be obtained. A photon emission line following the {beta} decay into the first excited state of {sup 50}Cr could not be observed, resulting in a lower limit on the half-life of the {beta}-decay branch of 1.7x10{sup 18} years. This is not in good agreement with a claimed observation of this decay branch published in 1989.

  11. Degenerate mitochondria

    PubMed Central

    van der Giezen, Mark; Tovar, Jorge

    2005-01-01

    Mitochondria are the main sites of biological energy generation in eukaryotes. These organelles are remnants of a bacterial endosymbiont that took up residence inside a host cell over 1,500 million years ago. Comparative genomics studies suggest that the mitochondrion is monophyletic in origin. Thus, the original mitochondrial endosymbiont has evolved independently in anaerobic and aerobic environments that are inhabited by diverse eukaryotic lineages. This process has resulted in a collection of morphologically, genetically and functionally heterogeneous organelle variants that include anaerobic and aerobic mitochondria, hydrogenosomes and mitosomes. Current studies aim to determine whether a central common function drives the retention of mitochondrial organelles in different eukaryotic organisms. PMID:15940286

  12. Macular Degeneration Partnership

    MedlinePLUS

    ... materials. Click Here AMD (Age Related Macular Degeneration) Partnership Listen Welcome! If you or a family member ... Use | Donor Bill of Rights | Disclaimer Macular Degeneration Partnership is an educational program of The Discovery Eye ...

  13. Macular Degeneration: An Overview.

    ERIC Educational Resources Information Center

    Chalifoux, L. M.

    1991-01-01

    This article presents information on macular degeneration for professionals helping persons with this disease adjust to their visual loss. It covers types of macular degeneration, the etiology of the disease, and its treatment. Also considered are psychosocial problems and other difficulties that persons with age-related macular degeneration face.…

  14. Biomechanics of Disc Degeneration

    PubMed Central

    Palepu, V.; Kodigudla, M.; Goel, V. K.

    2012-01-01

    Disc degeneration and associated disorders are among the most debated topics in the orthopedic literature over the past few decades. These may be attributed to interrelated mechanical, biochemical, and environmental factors. The treatment options vary from conservative approaches to surgery, depending on the severity of degeneration and response to conservative therapies. Spinal fusion is considered to be the “gold standard” in surgical methods till date. However, the association of adjacent level degeneration has led to the evolution of motion preservation technologies like spinal arthroplasty and posterior dynamic stabilization systems. These new technologies are aimed to address pain and preserve motion while maintaining a proper load sharing among various spinal elements. This paper provides an elaborative biomechanical review of the technologies aimed to address the disc degeneration and reiterates the point that biomechanical efficacy followed by long-term clinical success will allow these nonfusion technologies as alternatives to fusion, at least in certain patient population. PMID:22745914

  15. Acquired hepatocerebral degeneration

    PubMed Central

    Renjen, Pushpendra Nath; Khanna, Laxmi; Rastogi, Ruchi; Khan, Nadeem Israr

    2013-01-01

    Acquired (non-Wilsonian) hepatocerebral degeneration is a rare irreversible neurological syndrome that occurs in patients with chronic liver disease associated with multiple metabolic insults. Van Woerkom was the first to describe acquired hepatocerebral degeneration in 1914 followed by the landmark article by Victor et al in 1965. Multiple bouts of hepatic coma are the only known risk factors that trigger this devastating neurodegenerative disease with features suggesting toxic exposure to the brain. Clinically and pathologically the disorder is similar to Wilson's disease although subtle differences in immunostaining of glial fibrillar acidic protein have been documented. Acquired hepatocerebral degeneration occurs in 0.8–2% of patients with cirrhosis. As acquired hepatocerebral degeneration is relatively rare, we are reporting one such case from our hospital in a 50-year-old male patient who had long-standing portal systemic shunt and presented with progressive cognitive decline, bradykinesia, tremors and bilateral extrapyramidal signs. PMID:23780767

  16. Double Degenerate Binary Systems

    SciTech Connect

    Yakut, K. [University of Ege, Department of Astronomy and Space Sciences, 35100-Izmir (Turkey)

    2011-09-21

    In this study, angular momentum loss via gravitational radiation in double degenerate binary (DDB)systems (NS + NS, NS + WD, WD + WD, and AM CVn) is studied. Energy loss by gravitational waves has been estimated for each type of systems.

  17. Quantitative T2* (T2 Star) Relaxation Times Predict Site Specific Proteoglycan Content and Residual Mechanics of the Intervertebral Disc Throughout Degeneration

    PubMed Central

    Ellingson, Arin M.; Nagel, Tina M.; Polly, David W.; Ellermann, Jutta; Nuckley, David J.

    2014-01-01

    Degeneration alters the biochemical composition of the disc, affecting the mechanical integrity leading to spinal instability. Quantitative T2* MRI probes water mobility within the macromolecular network, a potentially more sensitive assessment of disc health. We determined the relationship between T2* relaxation time and proteoglycan content, collagen content, and compressive mechanics throughout the degenerative spectrum. Eighteen human cadaveric lumbar (L4–L5) discs were imaged using T2* MRI. The T2* relaxation time at five locations (nucleous pulposus or NP, anterior annulus fibrosis or AF, posterior AF, inner AF, and outer AF) was correlated with sulfated-glycosaminoglycan (s-GAG) content, hydroxyproline content, and residual stress and strain at each location. T2* relaxation times were significantly correlated with s-GAG contents in all test locations and were particularly strong in the NP (r = 0.944; p < 0.001) and inner AF (r = 0.782; p < 0.001). T2* relaxation times were also significantly correlated with both residual stresses and excised strains in the NP (r = 0.857; p < 0.001: r = 0.816; p < 0.001), inner AF (r = 0.535; p = 0.022: r = 0.516; p = 0.028), and outer AF (r = 0.668; p = 0.002: r = 0.458; p = 0.041). These strong correlations highlight T2* MRI’s ability to predict the biochemical and mechanical health of the disc. T2* MRI assessment of disc health is a clinically viable tool showing promise as a biomarker for distinguishing degenerative changes. PMID:24788830

  18. Protonation behavior of histidine 24 and histidine 119 in forming the pH 4 folding intermediate of apomyoglobin.

    PubMed

    Geierstanger, B; Jamin, M; Volkman, B F; Baldwin, R L

    1998-03-24

    Heteronuclear NMR methods are used to study the protonation of histidine and aspartate residues in the acid-induced unfolding of recombinant sperm whale apomyoglobin. The results are combined with fluorescence and circular dichroism measurements of acid-induced unfolding of wild-type and double mutant (H24V/H119F) proteins. They are consistent with a simple model in which the failure to protonate a single buried histidine, H24, is largely responsible for the partial unfolding of native (N) wild-type apomyoglobin to the pH 4 folding intermediate (I). H24 is known to form an unusual interaction in which its side chain is buried and hydrogen-bonded to the side chain of H119. Two-dimensional 1H-15N heteronuclear NMR spectra indicate that H24 is present in the rare delta tautomeric form and remains neutral until N unfolds to I, while H119 becomes protonated before the N --> I reaction occurs. In the H24V/H119F double mutant, all histidines are protonated in N and the N --> I reaction occurs at lower pH. Therefore, the protonation of aspartate and/or glutamate residues must provide an additional driving force for the N to I reaction. Two-dimensional 1H-13C NMR experiments are used to measure the protonation of aspartates in selectively 13C-labeled apomyoglobin; the results indicate that none of the aspartate residues has a strongly depressed pKa in N, as would be expected if it forms a stabilizing salt bridge. PMID:9521748

  19. Alternative splicing and retinal degeneration

    PubMed Central

    Liu, Melissa M.; Zack, Donald J.

    2014-01-01

    Alternative splicing is highly regulated in tissue-specific and development-specific patterns, and it has been estimated that 15% of disease-causing point mutations affect pre-mRNA splicing. In this review, we consider the cis-acting splice site and trans-acting splicing factor mutations that affect pre-mRNA splicing and contribute to retinal degeneration. Numerous splice site mutations have been identified in retinitis pigmentosa and various cone-rod dystrophies. For example, mutations in alternatively spliced retina-specific exons of the widely expressed RPGR and COL2A1 genes lead primarily to X-linked retinitis pigmentosa and ocular variants of Stickler Syndrome, respectively. Furthermore, mutations in general pre-mRNA splicing factors, such as PRPF31, PRPF8, and PRPF3, predominantly cause autosomal dominant retinitis pigmentosa. These findings suggest an important role for pre-mRNA splicing in retinal homeostasis and the pathogenesis of retinal degenerative diseases. The development of novel therapeutic strategies to modulate aberrant splicing, including small molecule based therapies, has the potential to lead to the development of new treatments for retinal degenerative diseases. PMID:23647439

  20. Degeneration in dysplastic hips

    Microsoft Academic Search

    Steffen Jacobsen; Lone Rømer; Kjeld Søballe

    2005-01-01

    Background  Hip dysplasia is considered pre-osteoarthritic, causing degeneration in young individuals.\\u000a \\u000a \\u000a \\u000a Objective  To determine the pattern of degenerative change in moderate to severely dysplastic hips in young patients.\\u000a \\u000a \\u000a \\u000a Design and patients  One hundred and ninety-three consecutively-referred younger patients with hip pain believed to be caused by hip dysplasia\\u000a constituted the study cohort. The average age was 35.5 years (range, 15–61 years). They were

  1. Degenerate Primer Design via Clustering

    Microsoft Academic Search

    Xintao Wei; David N. Kuhn; Giri Narasimhan

    2003-01-01

    This paper describes a new strategy for designing degenerate primers for a given multiple alignment of amino acid sequences. Degenerate primers are useful for amplifying homologous genes. However, when a large collection of sequences is considered, no consensus region may exist in the multiple alignment, making it impossible to design a single pair of primers for the collection. In such

  2. Sites

    Microsoft Academic Search

    Seth Bates; Tony Smith

    \\u000a SharePoint Foundation 2010 provides the core document management, list management, workflow, collaboration, and application\\u000a platform services for a SharePoint environment. SharePoint sites are the foundation on which business solutions based on the\\u000a Office system store and manage information. Sites provide locations where groups of people can work together and share information.\\u000a They can also be used to collect team and

  3. Acquired hepatocerebral degeneration.

    PubMed

    Meissner, Wassilios; Tison, François

    2011-01-01

    Repeated episodes of liver failure or chronic liver cirrhosis may cause acquired (non-Wilsonian) hepatocerebral degeneration (AHCD). Patients with AHCD may show cognitive deficits, ataxia, dysarthria, movement disorders, including parkinsonism, and sometimes myelopathy. Various parenchymal and cholestatic hepatic disorders may result in AHCD. Most patients with AHCD have evidence of portosystemic shunting without necessarily having abnormal liver function. Recent evidence suggests manganese plays a crucial role in the pathogenesis of AHCD. Excess dietary manganese is rapidly cleared by the liver before reaching the systemic circulation. In patients with cirrhosis and portosystemic shunting, manganese bypasses the liver and accumulates in the internal pallidum, while serum manganese levels may be normal or increased. Magnetic resonance imaging abnormalities mainly consist of a signal hyperintensity on T1-weighted images in the internal pallidum. It may also be seen in the putamen, the caudate nucleus, the capsula interna, the mesencephalon, and the cerebellum, and is believed to reflect local manganese accumulation. No specific treatment of AHCD exists. Controlled studies are lacking, but case reports have stressed the usefulness of branched-chain amino acid therapy, trientine, and liver transplantation for the treatment of movement disorders. Levodopa may be efficacious in the treatment of AHCD parkinsonism. PMID:21496578

  4. Chondroadherin fragmentation mediated by the protease HTRA1 distinguishes human intervertebral disc degeneration from normal aging.

    PubMed

    Akhatib, Bashar; Onnerfjord, Patrik; Gawri, Rahul; Ouellet, Jean; Jarzem, Peter; Heinegård, Dick; Mort, John; Roughley, Peter; Haglund, Lisbet

    2013-06-28

    Chondroadherin, a member of the leucine-rich repeat family, has previously been demonstrated to be fragmented in some juveniles with idiopathic scoliosis. This observation led us to investigate adults with disc degeneration. Immunoblotting analysis demonstrated that non-degenerate discs from three different age groups show no chondroadherin fragmentation. Furthermore, the chondroadherin fragments in adult degenerate disc and the juvenile scoliotic disc were compared via immunoblot analysis and appeared to have a similar size. We then investigated whether or not chondroadherin fragmentation increases with the severity of disc degeneration. Three different samples with different severities were chosen from the same disc, and chondroadherin fragmentation was found to be more abundant with increasing severity of degeneration. This observation led us to the creation of a neoepitope antibody to the cleavage site observed. We then observed that the cleavage site in adult degenerate discs and juvenile scoliotic discs was identical as confirmed by the neoepitope antibody. Consequently, investigation of the protease capable of cleaving chondroadherin at this site was necessary. In vitro digests of disc tissue demonstrated that ADAMTS-4 and -5; cathepsins K, B, and L; and MMP-3, -7, -12, and -13 were incapable of cleavage of chondroadherin at this site and that HTRA1 was indeed the only protease capable. Furthermore, increased protein levels of the processed form of HTRA1 were demonstrated in degenerate disc tissues via immunoblotting. The results suggest that chondroadherin fragmentation can be used as a biomarker to distinguish the processes of disc degeneration from normal aging. PMID:23673665

  5. Age-Related Macular Degeneration

    MedlinePLUS

    ... related Macular Degeneration: What is AMD? In This Topic What is AMD? Wet AMD Dry AMD Risk ... for More Information National Institute on Aging Related Topics Low Vision More Vision Topics The information in ...

  6. Degenerate quantum gases of strontium

    E-print Network

    Stellmer, Simon; Killian, Thomas C

    2013-01-01

    Degenerate quantum gases of alkaline-earth-like elements open new opportunities in research areas ranging from molecular physics to the study of strongly correlated systems. These experiments exploit the rich electronic structure of these elements, which is markedly different from the one of other species for which quantum degeneracy has been attained. Specifically, alkaline-earth-like atoms, such as strontium, feature metastable triplet states, narrow intercombination lines, and a non-magnetic, closed-shell ground state. This review covers the creation of quantum degenerate gases of strontium and the first experiments performed with this new system. It focuses on laser-cooling and evaporation schemes, which enable the creation of Bose-Einstein condensates and degenerate Fermi gases of all strontium isotopes, and shows how they are used for the investigation of optical Feshbach resonances, the study of degenerate gases loaded into an optical lattice, as well as the coherent creation of Sr_2 molecules.

  7. The Relationship between Opsin Overexpression and Photoreceptor Degeneration

    Microsoft Academic Search

    Elaine Tan; Quan Wang; Alexander B. Quiambao; Xiaoping Xu; Nasser M. Qtaishat; Neal S. Peachey; Janis Lem; Steven J. Fliesler; David R. Pepperberg; Muna I. Naash; Muayyad R. Al-Ubaidi

    2001-01-01

    PURPOSE. To characterize the process by which overexpression of normal opsin leads to photoreceptor degeneration. METHODS. Three transgenic mouse lines were generated that express different levels of an opsin with three amino acid modifications at the C terminus. These modifications created an epitopic site that can be readily distinguished from the endogenous protein using a bovine opsin-specific antibody. Evidence of

  8. Unraveling of the E-helices and Disruption of 4-Fold Pores Are Associated with Iron Mishandling in a Mutant Ferritin Causing Neurodegeneration

    SciTech Connect

    Baraibar, Martin A.; Muhoberac, Barry B.; Garringer, Holly J.; Hurley, Thomas D.; Vidal, Ruben (Indiana-Med); (IUPUI)

    2010-03-12

    Mutations in the coding sequence of the ferritin light chain (FTL) gene cause a neurodegenerative disease known as neuroferritinopathy or hereditary ferritinopathy, which is characterized by the presence of intracellular inclusion bodies containing the mutant FTL polypeptide and by abnormal accumulation of iron in the brain. Here, we describe the x-ray crystallographic structure and report functional studies of ferritin homopolymers formed from the mutant FTL polypeptide p.Phe167SerfsX26, which has a C terminus that is altered in amino acid sequence and length. The structure was determined and refined to 2.85 {angstrom} resolution and was very similar to the wild type between residues Ile-5 and Arg-154. However, instead of the E-helices normally present in wild type ferritin, the C-terminal sequences of all 24 mutant subunits showed substantial amounts of disorder, leading to multiple C-terminal polypeptide conformations and a large disruption of the normally tiny 4-fold axis pores. Functional studies underscored the importance of the mutant C-terminal sequence in iron-induced precipitation and revealed iron mishandling by soluble mutant FTL homopolymers in that only wild type incorporated iron when in direct competition in solution with mutant ferritin. Even without competition, the amount of iron incorporation over the first few minutes differed severalfold. Our data suggest that disruption at the 4-fold pores may lead to direct iron mishandling through attenuated iron incorporation by the soluble form of mutant ferritin and that the disordered C-terminal polypeptides may play a major role in iron-induced precipitation and formation of ferritin inclusion bodies in hereditary ferritinopathy.

  9. Imaging of corticobasal degeneration syndrome

    Microsoft Academic Search

    Masamichi Koyama; Akira Yagishita; Yasuhiro Nakata; Masaharu Hayashi; Mitsuaki Bandoh; Toshio Mizutani

    2007-01-01

    Introduction  Diagnosing corticobasal degeneration is often difficult on the basis of clinical symptoms and radiological images. We aimed\\u000a to clarify the imaging findings of corticobasal degeneration syndrome (CBDS).\\u000a \\u000a \\u000a \\u000a Methods  Included in the study were 16 patients (8 men, 8 women, 46–75 years old) with clinically diagnosed CBDS. We evaluated the\\u000a patients’ symptoms and signs, and MR and single-photon emission CT (SPECT) imaging findings.

  10. Degenerate primer design via clustering.

    PubMed

    Wei, Xintao; Kuhn, David N; Narasimhan, Giri

    2003-01-01

    This paper describes a new strategy for designing degenerate primers for a given multiple alignment of amino acid sequences. Degenerate primers are useful for amplifying homologous genes. However, when a large collection of sequences is considered, no consensus region may exist in the multiple alignment, making it impossible to design a single pair of primers for the collection. In such cases, manual methods are used to find smaller groups from the input collection so that primers can be designed for individual groups. Our strategy proposes an automatic grouping of the input sequences by using clustering techniques. Conserved regions are then detected for each individual group. Conserved regions are scored using a BlockSimilarity score, a novel alignment scoring scheme that is appropriate for this application. Degenerate primers are then designed by reverse translating the conserved amino acid sequences to the corresponding nucleotide sequences. Our program, DePiCt, was written in BioPerl and was tested on the Toll-Interleukin Receptor (TIR)and the non-TIR family of plant resistance genes. Existing programs for degenerate primer design were unable to find primers for these data sets. PMID:16452781

  11. [Clinical features of corticobasal degeneration].

    PubMed

    Farsang, Marianna; Takáts, Annamária; Szirmai, Imre; Kovács, Tibor

    2005-01-20

    Corticobasal degeneration was described in 1968 by Rebeiz, Kolodny and Richardson, who characterized the disease as a syndrome of asymmetric akinesis and rigidity, dystonia of the upper limb, apraxia, myoclonus and dementia. Atrophy of the frontal and parietal lobe, neuronal loss, gliosis and achromatic neurones (and nowadays astrocytic plaques) are the characteristic pathological features of the disease. Corticobasal degeneration is a rare or a rarely recognized disease and it is frequently misdiagnosed as Parkinson's disease. According to the Lang's criteria, corticobasal degeneration can be diagnosed in the presence of rigidity and one cortical symptom (apraxia, cortical sensory loss, alien hand) or in a patient with rigidity, dystonia and focal reflex myoclonus. Exclusion criteria are early dementia (as in primary degenerative dementias), early vertical gaze problems (as in progressive supranuclear palsy), resting tremor and good, sustained therapeutic response to levodopa (as in Parkinson's disease), severe autonomic problems (as in multiple system atrophy) and any pathology on imaging studies which might explain the clinical symptoms. It should be mentioned, that recently early dementia is recognized as an initial symptom of corticobasal degeneration. The authors present a case and review the literature to call attention to this disorder. PMID:15884398

  12. Topological Sweep in Degenerate Cases

    Microsoft Academic Search

    Eynat Rafalin; Diane L. Souvaine; Ileana Streinu

    2002-01-01

    Abstract: Topological sweep can contribute to efficient implementationsof various algorithms for data analysis. Real data, however, hasdegeneracies. The modification of the topological sweep algorithm presentedhere handles degenerate cases such as parallel or multiply concurrentlines without requiring numerical perturbations to achieve generalposition. Our method maintains the O(n) and O(n) time and space complexitiesof the original algorithm, and is robust and easy

  13. Degenerate Fermi gases of ytterbium.

    PubMed

    Fukuhara, Takeshi; Takasu, Yosuke; Kumakura, Mitsutaka; Takahashi, Yoshiro

    2007-01-19

    Evaporative cooling was performed to cool fermionic 173Yb atoms in a crossed optical dipole trap. The large elastic collision rate leads to efficient evaporation and we have successfully cooled the atoms to 0.37+/-0.06 of the Fermi temperature, that is to say, to a quantum degenerate regime. In this regime, a plunge of evaporation efficiency was observed as a result of Fermi degeneracy. PMID:17358662

  14. The degeneration of Y chromosomes.

    PubMed Central

    Charlesworth, B; Charlesworth, D

    2000-01-01

    Y chromosomes are genetically degenerate, having lost most of the active genes that were present in their ancestors. The causes of this degeneration have attracted much attention from evolutionary theorists. Four major theories are reviewed here: Muller's ratchet, background selection, the Hill Robertson effect with weak selection, and the 'hitchhiking' of deleterious alleles by favourable mutations. All of these involve a reduction in effective population size as a result of selective events occurring in a non-recombining genome, and the consequent weakening of the efficacy of selection. We review the consequences of these processes for patterns of molecular evolution and variation at loci on Y chromosomes, and discuss the results of empirical studies of these patterns for some evolving Y-chromosome and neo-Y-chromosome systems. These results suggest that the effective population sizes of evolving Y or neo-Y chromosomes are severely reduced, as expected if some or all of the hypothesized processes leading to degeneration are operative. It is, however, currently unclear which of the various processes is most important; some directions for future work to help to resolve this question are discussed. PMID:11127901

  15. General Pathophysiology in Retinal Degeneration

    PubMed Central

    Wert, Katherine J.; Lin, Jonathan H.; Tsang, Stephen H.

    2015-01-01

    Retinal degeneration, including that seen in age-related macular degeneration and retinitis pigmentosa (RP), is the most common form of neural degenerative disease in the world. There is great genetic and allelic heterogeneity of the various retinal dystrophies. Classifications of these diseases can be ambiguous, as there are similar clinical presentations in retinal degenerations arising from different genetic mechanisms. As would be expected, alterations in the activity of the phototransduction cascade, such as changes affecting the renewal and shedding of the photoreceptor OS, visual transduction, and/ or retinol metabolism have a great impact on the health of the retina. Mutations within any of the molecules responsible for these visual processes cause several types of retinal and retinal pigment epithelium degenerative diseases. Apoptosis has been implicated in the rod cell loss seen in a mouse model of RP, but the precise mechanisms that connect the activation of these pathways to the loss of phosphodiesterase (PDE6?) function has yet to be defined. Additionally, the activation of apoptosis by CCAAT/-enhancer-binding protein homologous protein (CHOP), after activation of the unfolded protein response pathway, may be responsible for cell death, although the mechanism remains unknown. However, the mechanisms of cell death after loss of function of PDE6, which is a commonly studied mammalian model in research, may be generalizable to loss of function of different key proteins involved in the phototransduction cascade. PMID:24732759

  16. Radial keratotomy associated endothelial degeneration

    PubMed Central

    Moshirfar, Majid; Ollerton, Andrew; Semnani, Rodmehr T; Hsu, Maylon

    2012-01-01

    Purpose To describe the presentation and clinical course of eyes with a history of radial keratotomy (RK) and varying degrees of endothelial degeneration. Methods Retrospective case series were used. Results Thirteen eyes (seven patients) were identified with clinical findings of significant guttata and a prior history of RK. The mean age of presentation for cornea evaluation was 54.3 years (range: 38–72 years), averaging 18.7 years (range: 11–33 years) after RK. The presentation of guttata varied in degree from moderate to severe. Best corrected visual acuity (BCVA) ranged from 20/25 to 20/80. All patients had a history of bilateral RK, except one patient who did not develop any guttata in the eye without prior RK. No patients reported a family history of Fuch’s Dystrophy. One patient underwent a penetrating keratoplasty in one eye and a Descemet’s stripping automated endothelial keratoplasty (DSAEK) in the other eye. Conclusions RK may induce a spectrum of endothelial degeneration. In elderly patients, the findings of guttata may signify comorbid Fuch’s dystrophy in which RK incisions could potentially hasten endothelial decomposition. In these select patients with stable cornea topography and prior RK, DSAEK may successfully treat RK endothelial degeneration. PMID:22347792

  17. Mathematical glimpse on the Y chromosome degeneration

    NASA Astrophysics Data System (ADS)

    Lobo, M. P.

    2006-04-01

    The Y chromosomes are genetically degenerate and do not recombine with their matching partners X. Non-recombination of XY pairs has been pointed out as the key factor for the degeneration of the Y chromosome. The aim here is to show that there is a mathematical asymmetry in sex chromosomes which leads to the degeneration of Y chromosomes even in the absence of XX and XY recombination. A model for sex-chromosome evolution in a stationary regime is proposed. The consequences of their asymmetry are analyzed and lead us to a couple of conclusions. First, Y chromosome degeneration shows up sqrt{2} more often than X chromosome degeneration. Second, if nature prohibits female mortalities from beeing exactly 50%, then Y chromosome degeneration is inevitable.

  18. New mouse primary retinal degeneration (rd-3)

    SciTech Connect

    Chang, B.; Hawes, N.L.; Roderick, T.H. (Jackson Lab., Bar Harbor, ME (United States)); Heckenlively, J.R. (UCLA Medical Center, Torrance, CA (United States))

    1993-04-01

    A new mouse retinal degeneration that appears to be an excellent candidate for modeling human retinitis pigmentosa is reported. In this degeneration, called rd-3, differentiation proceeds postnatally through 2 weeks, and photoreceptor degeneration starts by 3 weeks. The rod photoreceptor loss is essentially complete by 5 weeks, whereas remnant cone cells are seen through 7 weeks. This is the only mouse homozygous retinal degeneration reported to date in which photoreceptors are initially normal. Crosses with known mouse retinal degenerations rd, Rds, nr, and pcd are negative for retinal degeneration in offspring, and linkage analysis places rd-3 on mouse chromosome 1 at 10 [+-]2.5 cM distal to Akp-1. Homology mapping suggests that the homologous human locus should be on chromosome 1q. 32 refs., 3 figs., 3 tabs.

  19. Magnetic fields of degenerate stars

    NASA Astrophysics Data System (ADS)

    Chanmugam, G.

    The magnetic fields of degenerate stars are discussed with emphasis on such basic issues as how their magnetic field strengths are determined, their origin, and evolution. The magnetic fields of both white dwarfs and neutron stars are discussed together, and it is speculated that the origin and evolution of their fields may be related. It is also suggested that it may be possible to apply and test models for the evolution of the magnetic fields in neutron stars by using white dwarfs and vice versa.

  20. [Age-related macular degeneration].

    PubMed

    Budzinskaia, M V

    2014-01-01

    The review provides an update on the pathogenesis and new treatment modalities for neovascular age-related macular degeneration (AMD). The impact of polymorphism in particular genes, including complement factor H (CFH), age-related maculopathy susceptibility 2 (ARMS2/LOC387715), and serine peptidase (HTRA1), on AMD development is discussed. Clinical presentations of different forms of exudative AMD, that is classic, occult, or more often mixed choroidal neovascularization, retinal angiomatous proliferation, and choroidal polypoidal vasculopathy, are described. Particular attention is paid to the results of recent clinical trials and safety issues around the therapy. PMID:25715554

  1. Programmed cell death in intervertebral disc degeneration

    Microsoft Academic Search

    Chang-Qing Zhao; Lei-Sheng Jiang; Li-Yang Dai

    2006-01-01

    Intervertebral disc (IVD) degeneration is largely a process of destruction and failure of the extracellular matrix (ECM),\\u000a and symptomatic IVD degeneration is thought to be one of the leading causes of morbidity or life quality deterioration in\\u000a the elderly. To date, however, the mechanism of IVD degeneration is still not fully understood. Cellular loss from cell death\\u000a in the process

  2. Macular Degeneration Prevention and Risk Factors

    MedlinePLUS

    ... Alzheimer’s Disease Research Program Macular Degeneration Research Program National Glaucoma Research Program Molecular Neurodegeneration ... Foundation BrightFocus Foundation 22512 Gateway Center Drive Clarksburg, MD ...

  3. PRESENTING DEGENERATE RINGELHALL ALGEBRAS OF CYCLIC QUIVERS

    E-print Network

    Du, Jie

    ). This is achieved by establishing an isomorphism between H0(n) and the generic extension monoid algebra ZM(n) of (nPRESENTING DEGENERATE RINGEL­HALL ALGEBRAS OF CYCLIC QUIVERS BANGMING DENG, JIE DU AND ALEXANDRE­Hall algebra Hq(n) of a cyclic quiver (n), we give a presentation for the degenerate algebra H0(n

  4. Fusion Burning Waves in Degenerate Plasmas

    Microsoft Academic Search

    Pablo T. LeÛn; Shalom Eliezer; J. M. MartÌnez-Val; Mireia Piera

    Degenerate plasmas present very interesting features for fusion burning waves ignition and propagation. However, the outcome of fusion burning waves in non-degenerate plasmas is limited by the strength of ion-electron Coulomb collisions and subsequent energy loss mechanisms as electron heat conduction and radiation emission (bremsstrahlung.) In this paper, an analysis is presented on the degeneracy effects in the stopping power

  5. Degenerate adiabatic perturbation theory: Foundations and applications

    NASA Astrophysics Data System (ADS)

    Rigolin, Gustavo; Ortiz, Gerardo

    2014-08-01

    We present details and expand on the framework leading to the recently introduced degenerate adiabatic perturbation theory [Phys. Rev. Lett. 104, 170406 (2010), 10.1103/PhysRevLett.104.170406], and on the formulation of the degenerate adiabatic theorem, along with its necessary and sufficient conditions [given in Phys. Rev. A 85, 062111 (2012), 10.1103/PhysRevA.85.062111]. We start with the adiabatic approximation for degenerate Hamiltonians that paves the way to a clear and rigorous statement of the associated degenerate adiabatic theorem, where the non-Abelian geometric phase (Wilczek-Zee phase) plays a central role to its quantitative formulation. We then describe the degenerate adiabatic perturbation theory, whose zeroth-order term is the degenerate adiabatic approximation, in its full generality. The parameter in the perturbative power-series expansion of the time-dependent wave function is directly associated to the inverse of the time it takes to drive the system from its initial to its final state. With the aid of the degenerate adiabatic perturbation theory we obtain rigorous necessary and sufficient conditions for the validity of the adiabatic theorem of quantum mechanics. Finally, to illustrate the power and wide scope of the methodology, we apply the framework to a degenerate Hamiltonian, whose closed-form time-dependent wave function is derived exactly, and also to other nonexactly solvable Hamiltonians whose solutions are numerically computed.

  6. CARTAN'S STRUCTURAL EQUATIONS FOR DEGENERATE METRIC

    E-print Network

    Paris-Sud XI, Université de

    is the contraction between Date: November 2, 2011. Partially supported by Romanian Government grant PN II Idei 1187 in the degenerate case. These problems were avoided in [5], where instead of the metric con­ nection was used curvature tensor if the metric is non­degenerate. As it was shown there, the covariant contraction

  7. Axonal Degeneration in Motor Neuron Disease

    Microsoft Academic Search

    Lindsey R. Fischer; Jonathan D. Glass

    2007-01-01

    Growing evidence from animal models and patients with amyotrophic lateral sclerosis (ALS) suggests that distal axonal degeneration begins very early in this disease, long before symptom onset and motor neuron death. The cause of axonal degeneration is unknown, and may involve local axonal damage, withdrawal of trophic support from a diseased cell body, or both. It is increasingly clear that

  8. Macular degeneration: recent advances and therapeutic opportunities

    Microsoft Academic Search

    Amir Rattner; Jeremy Nathans

    2006-01-01

    The central retina mediates high acuity vision, and its progressive dysfunction due to macular degeneration is the leading cause of visual disability among adults in industrialized societies. Here, we summarize recent progress in understanding the pathophysiology of macular degeneration and the implications of this new knowledge for treatment and prevention. The past decade has witnessed remarkable advances in this field,

  9. Genetics of Frontotemporal Lobar Degeneration

    PubMed Central

    Galimberti, Daniela; Scarpini, Elio

    2012-01-01

    Frontotemporal lobar degeneration (FTLD), the most frequent neurodegenerative disorder with a presenile onset, presents with a spectrum of clinical manifestations, ranging from behavioral and executive impairment to language disorders and motor dysfunction. Familial aggregation is frequently reported, and about 10% of cases have an autosomal dominant transmission. Microtubule associated protein tau (MAPT) gene mutations have been the first ones identified and are associated with early onset behavioral variant frontotemporal dementia phenotype. More recently, progranulin gene (GRN) mutations were recognized in association with familial form of FTLD. In addition, other genes are linked to rare cases of familial FTLD. Lastly, a number of genetic risk factors for sporadic forms have also been identified. In this review, current knowledge about mutations at the basis of familial FTLD will be described, together with genetic risk factors influencing the susceptibility to FTLD. PMID:22536193

  10. Laser therapy and macular degeneration

    NASA Astrophysics Data System (ADS)

    Menchini, Ugo; Virgili, Gianni; Giansanti, Fabrizio; Giacomelli, Giovanni; Cappelli, Stefania

    2001-10-01

    Among macular diseases, choroidal neovascularization (CNV) is one of the most common causes of visual loss, especially in the form associated with age-related macular degeneration and pathologic myopia. Research on these diseases has recently evaluated new treatment modalities that use laser light differently; among these, photodynamic therapy (PDT) has been introduced in the clinical practice, allowing us to expand the possibility of reducing visual loss in patients affected by CNV. With PDT, a photosensitizer (verteporfin, VisudyneTM) is injected intravenously, and it selectively binds to new vessels; low-power laser light exposure then activates the drug, leading to oxidative damage of the endothelium and new vessels thrombosis. Yet, other therapies, such as transpupillary termotherapy, or the use of photocoagulation to cause feeder-vessel occlusion, could proof effective, but they need further investigation.

  11. Bilateral Wallerian Degeneration of the Pontocerebellar Tracts

    PubMed Central

    Hekimoglu, Azad; Suer Dogan, Ihsaniye; Turan, Aynur; Oztekin, Mehmet Fevzi; Hekimoglu, Baki

    2015-01-01

    Wallerian degeneration is the process of progressive demyelination and disintegration of the distal axonal segment following the transection of the axon or damage to the neuron. We report a case of a patient with Wallerian degeneration of the pontocerebellar tracts. She had a history of a pontine infarction 3 months ago. Wallerian degeneration of pontocerebellar tracts is seen bilaterally and symmetrically and is more visible in the middle cerebellar peduncles. Along the middle cerebellar peduncles hyperintense signal was detected on T2 weighted images. Wallerian degeneration of pontocerebellar tracts is a rare entity. It can occur bilaterally after a large pontine infarction. Magnetic resonance imaging seems to be the most effective technique for detection of Wallerian degeneration. In this report we want to mention this rare entity and to prevent wrong diagnosis. PMID:26171260

  12. A Monte Carlo algorithm for degenerate plasmas

    SciTech Connect

    Turrell, A.E., E-mail: a.turrell09@imperial.ac.uk; Sherlock, M.; Rose, S.J.

    2013-09-15

    A procedure for performing Monte Carlo calculations of plasmas with an arbitrary level of degeneracy is outlined. It has possible applications in inertial confinement fusion and astrophysics. Degenerate particles are initialised according to the Fermi–Dirac distribution function, and scattering is via a Pauli blocked binary collision approximation. The algorithm is tested against degenerate electron–ion equilibration, and the degenerate resistivity transport coefficient from unmagnetised first order transport theory. The code is applied to the cold fuel shell and alpha particle equilibration problem of inertial confinement fusion.

  13. Total absorption by degenerate critical coupling

    SciTech Connect

    Piper, Jessica R., E-mail: jrylan@stanford.edu; Liu, Victor; Fan, Shanhui, E-mail: shanhui@stanford.edu [Ginzton Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2014-06-23

    We consider a mirror-symmetric resonator with two ports. We show that, when excited from a single port, complete absorption can be achieved through critical coupling to degenerate resonances with opposite symmetry. Moreover, any time two resonances with opposite symmetry are degenerate in frequency and absorption is always significantly enhanced. In contrast, when two resonances with the same symmetry are nearly degenerate, there is no absorption enhancement. We numerically demonstrate these effects using a graphene monolayer on top of a photonic crystal slab, illuminated from a single side in the near-infrared.

  14. Peripheral Glia Have a Pivotal Role in the Initial Response to Axon Degeneration of Peripheral Sensory Neurons in Zebrafish

    PubMed Central

    Pope, Holly M.; Voigt, Mark M.

    2014-01-01

    Axon degeneration is a feature of many peripheral neuropathies. Understanding the organismal response to this degeneration may aid in identifying new therapeutic targets for treatment. Using a transgenic zebrafish line expressing a bacterial nitroreductase (Ntr)/mCherry fusion protein in the peripheral sensory neurons of the V, VII, IX, and X cranial nerves, we were able to induce and visualize the pathology of axon degeneration in vivo. Exposure of 4 days post fertilization Ntr larvae to the prodrug metronidazole (Met), which Ntr metabolizes into cytotoxic metabolites, resulted in dose-dependent cell death and axon degeneration. This was limited to the Ntr-expressing sensory neurons, as neighboring glia and motor axons were unaffected. Cell death was rapid, becoming apparent 3–4 hours after Met treatment, and was followed by phagocytosis of soma and axon debris by cells within the nerves and ganglia beginning at 4–5 hours of exposure. Although neutrophils appear to be activated in response to the degenerating neurons, they did not accumulate at the sites of degeneration. In contrast, macrophages were found to be attracted to the sites of the degenerating axons, where they phagocytosed debris. We demonstrated that peripheral glia are critical for both the phagocytosis and inflammatory response to degenerating neurons: mutants that lack all peripheral glia (foxD3?/?; Ntr) exhibit a much reduced reaction to axonal degeneration, resulting in a dramatic decrease in the clearance of debris, and impaired macrophage recruitment. Overall, these results show that this zebrafish model of peripheral sensory axon degeneration exhibits many aspects common to peripheral neuropathies and that peripheral glia play an important role in the initial response to this process. PMID:25058656

  15. Degeneration of biogenic superparamagnetic magnetite.

    PubMed

    Li, Y-L; Pfiffner, S M; Dyar, M D; Vali, H; Konhauser, K; Cole, D R; Rondinone, A J; Phelps, T J

    2009-01-01

    Magnetite crystals precipitated as a consequence of Fe(III) reduction by Shewanella algae BrY after 265 h incubation and 5-year anaerobic storage were investigated with transmission electron microscopy, Mössbauer spectroscopy and X-ray diffraction. The magnetite crystals were typically superparamagnetic with an approximate size of 13 nm. The lattice constants of the 265 h and 5-year crystals are 8.4164A and 8.3774A, respectively. The Mössbauer spectra indicated that the 265 h magnetite had excess Fe(II) in its crystal-chemistry (Fe(3+) (1.990)Fe(2+) (1.015)O(4)) but the 5-year magnetite was Fe(II)-deficient in stoichiometry (Fe(3+) (2.388)Fe(2+) (0.419)O(4)). Such crystal-chemical changes may be indicative of the degeneration of superparamagnetic magnetite through the aqueous oxidization of Fe(II) anaerobically, and the concomitant oxidation of the organic phases (fatty acid methyl esters) that were present during the initial formation of the magnetite. The observation of a corona structure on the aged magnetite corroborates the anaerobic oxidation of Fe(II) on the outer layers of magnetite crystals. These results suggest that there may be a possible link between the enzymatic activity of the bacteria and the stability of Fe(II)-excess magnetite, which may help explain why stable nano-magnetite grains are seldom preserved in natural environments. PMID:19200144

  16. Why do some intervertebral discs degenerate, when others (in the same spine) do not?

    PubMed

    Adams, Michael A; Lama, Polly; Zehra, Uruj; Dolan, Patricia

    2015-03-01

    This review suggests why some discs degenerate rather than age normally. Intervertebral discs are avascular pads of fibrocartilage that allow movement between vertebral bodies. Human discs have a low cell density and a limited ability to adapt to mechanical demands. With increasing age, the matrix becomes yellowed, fibrous, and brittle, but if disc structure remains intact, there is little impairment in function, and minimal ingrowth of blood vessels or nerves. Approximately half of old lumbar discs degenerate in the sense of becoming physically disrupted. The posterior annulus and lower lumbar discs are most affected, presumably because they are most heavily loaded. Age and genetic inheritance can weaken discs to such an extent that they are physically disrupted during everyday activities. Damage to the endplate or annulus typically decompresses the nucleus, concentrates stress within the annulus, and allows ingrowth of nerves and blood vessels. Matrix disruption progresses by mechanical and biological means. The site of initial damage leads to two disc degeneration "phenotypes": endplate-driven degeneration is common in the upper lumbar and thoracic spine, and annulus-driven degeneration is common at L4-S1. Discogenic back pain can be initiated by tissue disruption, and amplified by inflammation and infection. Healing is possible in the outer annulus only, where cell density is highest. We conclude that some discs degenerate because they are disrupted by excessive mechanical loading. This can occur without trauma if tissues are weakened by age and genetic inheritance. Moderate mechanical loading, in contrast, strengthens all spinal tissues, including discs. PMID:24753325

  17. A historical case of probable corticobasal degeneration?

    PubMed

    Ballan, G; Tison, F

    1997-11-01

    In 1925, Jean Lhermitte and colleagues published a work on spatial representation in apraxic patients, based on two illustrative cases. One of these displayed a clinical picture that would nowadays be clinically classified as probable corticobasal degeneration. PMID:9399241

  18. CONVERGENCE FOR STABILISATION OF DEGENERATELY CONVEX MINIMISATION

    E-print Network

    Bartels, Soeren

    CONVERGENCE FOR STABILISATION OF DEGENERATELY CONVEX MINIMISATION PROBLEMS S. BARTELS, C convergence of straightforward finite element approx- imations cannot be expected but is relevant in many applications. This paper establishes a modified discretization by stabilisation and proves its convergence

  19. Axon Degeneration: Where the Wlds Things Are

    PubMed Central

    Wang, Jack T.; Barres, Ben A.

    2015-01-01

    Expression of the Wlds protein significantly delays axon degeneration in injuries and diseases, but the mechanism for this protection is unknown. Two recent reports present evidence that axonal mitochondria are required for WldS-mediated axon protection. PMID:22497934

  20. Genetics Home Reference: Stargardt macular degeneration

    MedlinePLUS

    ... people with Stargardt macular degeneration, a fatty yellow pigment (lipofuscin) builds up in cells underlying the macula. ... acids ; gene ; inheritance ; inherited ; juvenile ; lipofuscin ; macula ; photoreceptor ; pigment ; prevalence ; protein ; recessive ; retina ; tissue ; toxic You may ...

  1. What Is Age-Related Macular Degeneration?

    MedlinePLUS

    ... to Z Age-related Macular Degeneration (AMD) Allergies Amblyopia (Lazy Eye) Astigmatism Bacterial Keratitis Bell's Palsy Blepharitis ... Refractive Surgery & LASIK Sunglasses Living EyeSmart About Ophthalmologists Adults Under 40 Adults 40 to 60 Adults Over ...

  2. A new degenerate Fermi gas apparatus

    E-print Network

    Setiawan, Widagdo

    2007-01-01

    In the summer of 2004, the BEC 2 lab of Wolfgang Ketterle's group at MIT started a new research direction of studying degenerate fermionic Lithium atoms in optical lattices. The major contributions to the new experimental ...

  3. EXCEPTIONAL BUNDLES ASSOCIATED TO DEGENERATIONS OF SURFACES

    E-print Network

    Hacking, Paul

    EXCEPTIONAL BUNDLES ASSOCIATED TO DEGENERATIONS OF SURFACES PAUL HACKING 1. Introduction In 1981 J HACKING F deforms in a unique way to a family of exceptional bundles on the fibers of Y/(0 S). Theorem 1

  4. [Presacral schwannoma with degenerated areas ("ancient schwannoma")].

    PubMed

    Netsch, C; Oberhagemann, K; Bach, T; Feyerabend, B; Gross, A J

    2010-10-01

    A presacral, degenerative schwannoma ("ancient schwannoma") is a rare entity. The clinical signs are nonspecific, and a reliable preoperative diagnosis is difficult. Tumor heterogeneity with calcifications may be seen in degenerated schwannomas on MRI or CT but not necessarily. First-line treatment is complete surgical excision. We present the case of a 44-year-old male who required surgery for a presacral mass. Histopathological examination revealed the diagnosis of a schwannoma with degenerated areas. PMID:20694717

  5. The Gravitational Demise of Cold Degenerate Stars

    E-print Network

    Fred C. Adams; Greg Laughlin; Manasse Mbonye; Malcolm J. Perry

    1998-08-23

    We consider the long term fate and evolution of cold degenerate stars under the action of gravity alone. Although such stars cannot emit radiation through the Hawking mechanism, the wave function of the star will contain a small admixture of black hole states. These black hole states will emit radiation and hence the star can lose its mass energy in the long term. We discuss the allowed range of possible degenerate stellar evolution within this framework.

  6. The Gravitational Demise of Cold Degenerate Stars

    E-print Network

    Adams, F C; Mbonye, M R; Perry, M J; Adams, Fred C; Laughlin, Greg; Mbonye, Manasse; Perry, Malcolm J.

    1998-01-01

    We consider the long term fate and evolution of cold degenerate stars under the action of gravity alone. Although such stars cannot emit radiation through the Hawking mechanism, the wave function of the star will contain a small admixture of black hole states. These black hole states will emit radiation and hence the star can lose its mass energy in the long term. We discuss the allowed range of possible degenerate stellar evolution within this framework.

  7. Shear viscosity of degenerate electron matter

    E-print Network

    P. S. Shternin

    2008-03-27

    We calculate the partial electron shear viscosity $\\eta_{ee}$ limited by electron-electron collisions in a strongly degenerate electron gas taking into account the Landau damping of transverse plasmons. The Landau damping strongly suppresses $\\eta_{ee}$ in the domain of ultrarelativistic degenerate electrons and modifies its %asymptotic temperature behavior. The efficiency of the electron shear viscosity in the cores of white dwarfs and envelopes of neutron stars is analyzed.

  8. Protection of Retina by ?B Crystallin in Sodium Iodate Induced Retinal Degeneration

    PubMed Central

    Zhou, Peng; Kannan, Ram; Spee, Christine; Sreekumar, Parameswaran G.; Dou, Guorui; Hinton, David R.

    2014-01-01

    Age-related macular degeneration (AMD) is a leading cause of blindness in the developed world. The retinal pigment epithelium (RPE) is a critical site of pathology in AMD and ?B crystallin expression is increased in RPE and associated drusen in AMD. The purpose of this study was to investigate the role of ?B crystallin in sodium iodate (NaIO3)-induced retinal degeneration, a model of AMD in which the primary site of pathology is the RPE. Dose dependent effects of intravenous NaIO3 (20-70 mg/kg) on development of retinal degeneration (fundus photography) and RPE and retinal neuronal loss (histology) were determined in wild type and ?B crystallin knockout mice. Absence of ?B crystallin augmented retinal degeneration in low dose (20 mg/kg) NaIO3-treated mice and increased retinal cell apoptosis which was mainly localized to the RPE layer. Generation of reactive oxygen species (ROS) was observed with NaIO3 in mouse and human RPE which increased further after ?B crystallin knockout or siRNA knockdown, respectively. NaIO3 upregulated AKT phosphorylation and peroxisome proliferator–activator receptor–? (PPAR?) which was suppressed after ?B crystallin siRNA knockdown. Further, PPAR? ligand inhibited NaIO3-induced ROS generation. Our data suggest that ?B crystallin plays a critical role in protection of NaIO3-induced oxidative stress and retinal degeneration in part through upregulation of AKT phosphorylation and PPAR? expression. PMID:24874187

  9. Antioxidative nanofullerol prevents intervertebral disk degeneration.

    PubMed

    Yang, Xinlin; Jin, Li; Yao, Lu; Shen, Francis H; Shimer, Adam L; Li, Xudong

    2014-01-01

    Compelling evidence suggests that reactive oxygen species (ROS) play a pivotal role in disk degeneration. Fullerol nanoparticles prepared in aqueous solution have been demonstrated to have outstanding ability to scavenge ROS. In this report, in vitro and in vivo models were used to study the efficacy of fullerol in preventing disk degeneration. For in vitro experiments, a pro-oxidant H2O2 or an inflammatory cytokine interleukin (IL)-1? was employed to induce degenerated phenotypes in human nucleus pulposus cells encapsulated in alginate beads, and fullerol was added in the culture medium. For the animal study, an annulus-puncture model with rabbit was created, and fullerol was injected into disks. It was shown that cytotoxicity and cellular ROS level induced by H2O2 were significantly diminished by fullerol. IL-1?-induced nitric oxide generation in culture medium was suppressed by fullerol as well. Gene-profile and biochemical assays showed that fullerol effectively reversed the matrix degradation caused by either H2O2 or IL-1?. The animal study delineated that intradiskal injection of fullerol prevented disk degeneration, increasing water and proteoglycan content and inhibiting ectopic bone formation. These results suggest that antioxidative fullerol may have a potential therapeutic application for disk degeneration. PMID:24876775

  10. The influence of occupation on lumbar degeneration.

    PubMed

    Videman, T; Battié, M C

    1999-06-01

    In many countries, back problems have been defined as occupational injuries. The belief underlying this injury model is that back symptoms are caused primarily by work-related mechanical factors that damage the structures of the spine, either through a single incident or repeated loading. Although the etiopathogenesis of degenerative findings in the disc and their relation to pain are poorly understood, changes in the disc are suspected of underlying many back symptoms. The focus of this article is on examining the relation between occupational factors and disc degeneration. Occupational factors suspected of accelerating spinal degeneration include accident-related trauma; heavy physical loading and materials handling, including lifting, bending, and twisting; prolonged sitting; and sustained nonneutral work postures and vehicular driving. There is evidence to suggest that occupational exposures have an effect on disc degeneration. However, these factors explain little of the variability in degeneration found in the adult population. Furthermore, the lack of a clear dose-response relation between time spent in various occupational loading conditions and degenerative findings adds to doubts about a strong causal link. The contribution of suspected occupational risk factors appears to be particularly modest when compared with familial influences, which reflect the combined effects of genes and early childhood environment. These findings challenge the dominant role assumed for occupational loading in disc degeneration and associated back problems, and suggest a more complex etiology. PMID:10361670

  11. Ill-posedness of degenerate dispersive equations

    NASA Astrophysics Data System (ADS)

    Ambrose, David M.; Simpson, Gideon; Wright, J. Douglas; Yang, Dennis G.

    2012-09-01

    In this paper we provide numerical and analytical evidence that some degenerate dispersive partial differential equations are ill-posed. Specifically we study the K (2, 2) equation ut = (u2)xxx + (u2)x and the ‘degenerate Airy’ equation ut = 2uuxxx. For K (2, 2) our results are computational in nature: we conduct a series of numerical simulations which demonstrate that data which is very small in H2 can be of unit size at a fixed time which is independent of the data's size. For the degenerate Airy equation, our results are fully rigorous: we prove the existence of a compactly supported self-similar solution which, when combined with certain scaling invariances, implies ill-posedness (also in H2).

  12. THE CELL STRESS MACHINERY AND RETINAL DEGENERATION

    PubMed Central

    Athanasiou, Dimitra; Aguilà, Monica; Bevilacqua, Dalila; Novoselov, Sergey S.; Parfitt, David A.; Cheetham, Michael E.

    2015-01-01

    Retinal degenerations are a group of clinically and genetically heterogeneous disorders characterised by progressive loss of vision due to neurodegeneration. The retina is a highly specialised tissue with a unique architecture and maintaining homeostasis in all the different retinal cell types is crucial for healthy vision. The retina can be exposed to a variety of environmental insults and stress, including light-induced damage, oxidative stress and inherited mutations that can lead to protein misfolding. Within retinal cells there are different mechanisms to cope with disturbances in proteostasis, such as the heat shock response, the unfolded protein response and autophagy. In this review, we discuss the multiple responses of the retina to different types of stress involved in retinal degenerations, such as retinitis pigmentosa, age-related macular degeneration and glaucoma. Understanding the mechanisms that maintain and re-establish proteostasis in the retina is important for developing new therapeutic approaches to fight blindness. PMID:23684651

  13. The cell stress machinery and retinal degeneration.

    PubMed

    Athanasiou, Dimitra; Aguilà, Monica; Bevilacqua, Dalila; Novoselov, Sergey S; Parfitt, David A; Cheetham, Michael E

    2013-06-27

    Retinal degenerations are a group of clinically and genetically heterogeneous disorders characterised by progressive loss of vision due to neurodegeneration. The retina is a highly specialised tissue with a unique architecture and maintaining homeostasis in all the different retinal cell types is crucial for healthy vision. The retina can be exposed to a variety of environmental insults and stress, including light-induced damage, oxidative stress and inherited mutations that can lead to protein misfolding. Within retinal cells there are different mechanisms to cope with disturbances in proteostasis, such as the heat shock response, the unfolded protein response and autophagy. In this review, we discuss the multiple responses of the retina to different types of stress involved in retinal degenerations, such as retinitis pigmentosa, age-related macular degeneration and glaucoma. Understanding the mechanisms that maintain and re-establish proteostasis in the retina is important for developing new therapeutic approaches to fight blindness. PMID:23684651

  14. Axillary Schwannoma with Extensive Cystic Degeneration

    PubMed Central

    Jadhav, Chaithra R; Angeline, N R; Kumar, Bipin; Bhat, Ramachandra V; Balachandran, G

    2013-01-01

    Schwannoma affect mainly head, neck, and flexor aspect of the limbs. Neurogenic tumors arising from the brachial plexus are rare and axillary schwannoma is extremely uncommon. Cystic degeneration is common in longstanding cases and which when aspirated may yield only macrophages or lymphocytes leading to false diagnosis of the case in spite of strong clinical suspicion. We report one such rare case of a solitary axillary schwannoma with extensive cystic degeneration, which was misdiagnosed on fine needle aspiration cytology and subsequently confirmed by the histopathological examination and immunohistochemistry. PMID:24014973

  15. Two stream instabilities in degenerate quantum plasmas

    E-print Network

    S. Son

    2013-10-18

    The quantum mechanical effect on the plasma two-stream instability is studied based on the dielectric function approach. The analysis suggests that the degenerate plasma relevant to the inertial confinement fusion behaves differently from classical plasmas when the electron drift velocity is comparable to the Fermi velocity. For high wave vector comparable to the Fermi wave vector, the degenerate quantum plasma has larger regime of the two-stream instabilities than the classical plasma. A regime, where the plasma waves with the frequency larger than 1.5 times of the Langmuir wave frequency become unstable to the two-stream instabilities, is identified.

  16. Degenerate quasicrystal of hard triangular bipyramids.

    PubMed

    Haji-Akbari, Amir; Engel, Michael; Glotzer, Sharon C

    2011-11-18

    We report a degenerate quasicrystal in Monte Carlo simulations of hard triangular bipyramids each composed of two regular tetrahedra sharing a single face. The dodecagonal quasicrystal is similar to that recently reported for hard tetrahedra [Haji-Akbari et al., Nature (London) 462, 773 (2009)] but degenerate in the pairing of tetrahedra, and self-assembles at packing fractions above 54%. This notion of degeneracy differs from the degeneracy of a quasiperiodic random tiling arising through phason flips. Free energy calculations show that a triclinic crystal is preferred at high packing fractions. PMID:22181897

  17. CT of sarcomatous degeneration in neurofibromatosis

    SciTech Connect

    Coleman, B.G. (Hospital of the Univ. of Pennsylvania, Philadelphia); Arger, P.H.; Dalinka, M.K.; Obringer, A.C.; Raney, B.R.; Meadows, A.T.

    1983-02-01

    Neurofibromatosis is a relatively common disorder that often involves many organ systems. One of the least understood aspects of this malady is a well documented potential for sarcomatous degeneration of neurofibromas. The inability to identify patients at risk and the lack of noninvasive screening methods for symptomatic patients often leads to late diagnosis. In six of seven subsequently proven neurofibrosarcomas, CT demonstrated low-density areas that histopathologically appeared to be due to necrosis, hemorrhage, and/or cystic degeneration. The density differences within these sarcomas were enhanced by the intravenous adminstration of iodinated contrast agents.

  18. Fusion burning waves in degenerate plasmas

    Microsoft Academic Search

    Pablo T. León; Shalom Eliezer; J. M. Martínez-Val; Mireia Piera

    2001-01-01

    The outcome of fusion burning waves in non-degenerate plasmas is limited by the strength of ion-electron Coulomb collisions and subsequent energy loss mechanisms as electron heat conduction and radiation emission. In this Letter, an analysis is presented on the degeneracy effects in the stopping power of suprathermal charged particles and in the energy transmitted from ions to electrons by Coulomb

  19. Fusion burning waves in degenerate plasmas

    Microsoft Academic Search

    Pablo T León; Shalom Eliezer; J. M Mart??nez-Val; Mireia Piera

    2001-01-01

    The outcome of fusion burning waves in non-degenerate plasmas is limited by the strength of ion–electron Coulomb collisions and subsequent energy loss mechanisms as electron heat conduction and radiation emission. In this Letter, an analysis is presented on the degeneracy effects in the stopping power of suprathermal charged particles and in the energy transmitted from ions to electrons by Coulomb

  20. Mitochondrial Transport and Function in Axon Degeneration

    E-print Network

    O'Donnell, Kelley

    2013-01-01

    death in this model is not a stereotyped process of retrograde, “dying-dying-back” process in which axon degeneration is required for cell death.dying-back” of dopaminergic neurons (Hornykiewicz, 1998), with synapse loss initiating a retrograde degenerative process that leads to cell death.

  1. SLOW DYNAMICS VIA DEGENERATE VARIATIONAL ASYMPTOTICS

    Microsoft Academic Search

    GEORG GOTTWALD; MARCEL OLIVER

    We introduce the method of degenerate variational asymptotics for a class of singularly perturbed ordinary differential equations whose lead- ing order behavior is dominated by gyroscopic forces. Such systems exhibit dynamics on two separate time scales which are dynamically linked with no explicit splitting into slow and fast subsystems. We derive approximate equa- tions for the slow motion to arbitrary

  2. 9 CFR 311.35 - Muscular inflammation, degeneration, or infiltration.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2 2012-01-01 2012-01-01 false Muscular inflammation, degeneration, or infiltration. 311.35 Section 311...OTHERWISE ADULTERATED CARCASSES AND PARTS § 311.35 Muscular inflammation, degeneration, or infiltration. (a) If...

  3. 9 CFR 311.35 - Muscular inflammation, degeneration, or infiltration.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2 2013-01-01 2013-01-01 false Muscular inflammation, degeneration, or infiltration. 311.35 Section 311...OTHERWISE ADULTERATED CARCASSES AND PARTS § 311.35 Muscular inflammation, degeneration, or infiltration. (a) If...

  4. 9 CFR 311.35 - Muscular inflammation, degeneration, or infiltration.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2 2014-01-01 2014-01-01 false Muscular inflammation, degeneration, or infiltration. 311.35 Section 311...OTHERWISE ADULTERATED CARCASSES AND PARTS § 311.35 Muscular inflammation, degeneration, or infiltration. (a) If...

  5. Degenerate Monge-Ampere equations over projective manifolds

    E-print Network

    Zhang, Zhou, Ph. D. Massachusetts Institute of Technology

    2006-01-01

    In this thesis, we study degenerate Monge-Ampere equations over projective manifolds. The main degeneration is on the cohomology class which is Kähler in classic cases. Our main results concern the case when this class is ...

  6. Influences of osteoporosis and disc degeneration on lumbar spinal stability

    Microsoft Academic Search

    2003-01-01

    Disc degeneration and osteoporosis are two main factors affecting the elderly and impacting the quality of life. The aims of this study were to provide the information on mechanical changes resulting from disc degeneration and osteoporosis and further to understand their roles in segmental instability. The influences of disc degeneration and osteoporosis were investigated using a 3?dimensional finite element model

  7. NEUTRINO PROCESSES IN PARTIALLY DEGENERATE NEUTRON MATTER

    SciTech Connect

    Bacca, S.; Hally, K. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Liebendoerfer, M.; Perego, A. [Department of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel (Switzerland); Pethick, C. J. [Niels Bohr International Academy, Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen O (Denmark); Schwenk, A. [ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany)

    2012-10-10

    We investigate neutrino processes for conditions reached in simulations of core-collapse supernovae. In regions where neutrino-matter interactions play an important role, matter is partially degenerate, and we extend earlier work that addressed the degenerate regime. We derive expressions for the spin structure factor in neutron matter, which is a key quantity required for evaluating rates of neutrino processes. We show that, for essentially all conditions encountered in the post-bounce phase of core-collapse supernovae, it is a very good approximation to calculate the spin relaxation rates in the nondegenerate limit. We calculate spin relaxation rates based on chiral effective field theory interactions and find that they are typically a factor of two smaller than those obtained using the standard one-pion-exchange interaction alone.

  8. Inflammation in age-related macular degeneration.

    PubMed

    Ozaki, Ema; Campbell, Matthew; Kiang, Anna-Sophia; Humphries, Marian; Doyle, Sarah L; Humphries, Peter

    2014-01-01

    Age-related macular degeneration (AMD) is the leading cause of legal blindness in elderly individuals in the developed world, affecting 30-50 million people worldwide. AMD primarily affects the macular region of the retina that is responsible for the majority of central, color and daytime vision. The presence of drusen, extracellular protein aggregates that accumulate under the retinal pigment epithelium (RPE), is a major pathological hallmark in the early stages of the disease. The end stage 'dry' and 'wet' forms of the disease culminate in vision loss and are characterized by focal degeneration of the RPE and cone photoreceptors, and choroidal neovascularization (CNV), respectively. Being a multifactorial and genetically heterogeneous disease, the pathophysiology of AMD remains unclear, yet, there is ample evidence supporting immunological and inflammatory processes. Here, we review the recent literature implicating some of these immune processes in human AMD and in animal models. PMID:24664703

  9. Inflammation in intervertebral disc degeneration and regeneration

    PubMed Central

    Molinos, Maria; Almeida, Catarina R.; Caldeira, Joana; Cunha, Carla; Gonçalves, Raquel M.; Barbosa, Mário A.

    2015-01-01

    Intervertebral disc (IVD) degeneration is one of the major causes of low back pain, a problem with a heavy economic burden, which has been increasing in prevalence as populations age. Deeper knowledge of the complex spatial and temporal orchestration of cellular interactions and extracellular matrix remodelling is critical to improve current IVD therapies, which have so far proved unsatisfactory. Inflammation has been correlated with degenerative disc disease but its role in discogenic pain and hernia regression remains controversial. The inflammatory response may be involved in the onset of disease, but it is also crucial in maintaining tissue homeostasis. Furthermore, if properly balanced it may contribute to tissue repair/regeneration as has already been demonstrated in other tissues. In this review, we focus on how inflammation has been associated with IVD degeneration by describing observational and in vitro studies as well as in vivo animal models. Finally, we provide an overview of IVD regenerative therapies that target key inflammatory players. PMID:25673296

  10. Computer identification of degenerated urothelial cells.

    PubMed

    Koss, L G; Bartels, P H; Sherman, A; Sychra, J J; Schreiber, K; Moussouris, H S; Wied, G L

    1980-06-01

    Computer algorithms were developed to identify very poorly preserved, degenerated urothelial cells from the urinary sediment. Cell images were analyzed by two methods: the first one based on nucleus-finding algorithms (determination of nuclear boundaries) and the second based on the analysis of histograms of optical density. Discrimination between benign and malignant degenerated cells could be accomplished by both methods, although the misclassification of cells rose from +/- 10% by the first approach to +/- 15% by the second approach. Most important, however, useful algorithms were obtained and incorporated into the TICAS file for the identification of this large group of urothelial cells as a significant step in the automated analysis of the cells in thr urinary sediment. PMID:7447181

  11. Bifurcation from a normally degenerate manifold

    Microsoft Academic Search

    D. R. J. Chillingworth; L. Sbano

    2010-01-01

    Local bifurcation theory typically deals with the response of a degenerate\\u000abut isolated equilibrium state or periodic orbit of a dynamical system to\\u000aperturbations controlled by one or more independent parameters, and\\u000acharacteristically uses tools from singularity theory. There are many\\u000asituations, however, in which the equilibrium state or periodic orbit is not\\u000aisolated but belongs to a manifold $S$

  12. Widespread spinal cord involvement in corticobasal degeneration

    Microsoft Academic Search

    Yasushi Iwasaki; Mari Yoshida; Manabu Hattori; Yoshio Hashizume; Gen Sobue

    2005-01-01

    We examined spinal cord lesions in eight patients with a pathological diagnosis of corticobasal degeneration (CBD). Using Gallyas-Braak (G-B) staining or AT-8 tau immunostaining, a few neuropil threads were identified in the white matter of the CBD spinal cords, mainly in the anterior funiculus, whereas the posterior funiculus was well preserved without threads. In the gray matter of the CBD

  13. Hypertrophic olivary degeneration secondary to pontine haemorrhage.

    PubMed

    Wein, Sara; Yan, Bernard; Gaillard, Frank

    2015-07-01

    We report a 58-year-old man who developed hyptertrophic olivary degeneration (HOD) after haemorrhage of a cavernous malformation in the pons. Lesions of the triangle of Guillain and Mollaret (the dentatorubro-olivary pathway) may lead to HOD, a secondary transsynaptic degeneration of the inferior olivary nucleus. HOD is considered unique because the degenerating olive initially becomes hypertrophic rather than atrophic. The primary lesion causing pathway interruption is often haemorrhage, either due to hypertension, trauma, surgery or, as in our patient, a vascular malformation such as a cavernoma. Ischaemia and demyelination can also occasionally be the inciting events. The classic clinical presentation of HOD is palatal myoclonus, although not all patients with HOD develop this symptom. The imaging features of HOD evolve through characteristic phases. The clue to the diagnosis of HOD is recognition of the distinct imaging stages and identification of a remote primary lesion in the triangle of Guillain and Mollaret. Familiarity with the classic imaging findings of this rare phenomenon is necessary in order to avoid misdiagnosis and prevent unnecessary intervention. PMID:25863998

  14. Tensor Operations on Degenerate Inner Product Spaces

    E-print Network

    Ovidiu Cristinel Stoica

    2011-12-26

    Well-known operations defined on a non-degenerate inner product vector space are extended to the case of a degenerate inner product. The main obstructions to the extension of these operations to the degenerate case are (1) the index lowering operation is not invertible, and (2) we cannot associate to the inner product in a canonical way a reciprocal inner product on the dual of the vector space. This article shows how these obstructions can be avoided naturally, allowing a canonical definition of covariant contraction for some important special cases. The primary motivation of this article is to lay down the algebraic foundation for the construction of invariants in Singular Semi-Riemannian Geometry, especially those related to the curvature. It turns out that the operations discussed here are enough for this purpose (arXiv:1105.0201, arXiv:1105.3404, arXiv:1111.0646). Such invariants can be applied to the study of singularities in the theory of General Relativity (arXiv:1111.4837, arXiv:1111.4332, arXiv:1111.7082, arXiv:1108.5099, arXiv:1112.4508).

  15. Degeneration in vivo of rat hippocampal neurons by wild-type Alzheimer amyloid precursor protein overexpressed by adenovirus-mediated gene transfer.

    PubMed

    Nishimura, I; Uetsuki, T; Dani, S U; Ohsawa, Y; Saito, I; Okamura, H; Uchiyama, Y; Yoshikawa, K

    1998-04-01

    In an attempt to elucidate the pathological implications of intracellular accumulation of the amyloid precursor protein (APP) in postmitotic neurons in vivo, we transferred APP695 cDNA into rat hippocampal neurons by using a replication-defective adenovirus vector. We first improved the efficiency of adenovirus-mediated gene transfer into neurons in vivo by using hypertonic mannitol. When a beta-galactosidase-expressing recombinant adenovirus suspended in 1 M mannitol was injected into a dorsal hippocampal region, a number of neurons in remote areas were positively stained, presumably owing to increased retrograde transport of the virus. When an APP695-expressing adenovirus was injected into the same site, part of the infected neurons in the hippocampal formation underwent severe degeneration in a few days, whereas astrocytes near the injection site showed no apparent degeneration. These degenerating neurons accumulated different epitopes of APP, and beta/A4 protein (Abeta)-immunoreactive materials were undetected in the extracellular space. A small number of degenerating neurons showed nuclear DNA fragmentation. Electron microscopic examinations demonstrated that degenerating neurons had shrunken perikarya along with synaptic abnormalities. Microglial cells/macrophages were often found in close proximity to degenerating neurons, and in some cases they phagocytosed these neurons. These results suggest that intracellular accumulation of wild-type APP695 causes a specific type of neuronal degeneration in vivo in the absence of extracellular Abeta deposition. PMID:9502800

  16. Kramers-degenerated NV+113C spin systems in diamond: analytical description

    NASA Astrophysics Data System (ADS)

    Nizovtsev, Alexander P.; Kilin, Sergei Y.; Pushkarchuk, Alexander L.; Kuten, Semen A.

    2013-02-01

    Spin systems consisted of single electronic spin S=1 of the NV center and nearby nuclear spins I=1/2 of 13C atoms disposed in diamond lattice near the center can be used as a small register of a quantum computer or as a sensor of a magnetic field. At odd number of nuclear spins eigenvalues of the spin systems at zero external magnetic field are at least twofold degenerated (Kramers degeneration) due to time reversal invariance of the spin Hamiltonian. This degeneracy is lifted only by external magnetic field regardless of the presence of any electric (crystal) field which can also lift the degeneracy thus hindering measurement of the magnetic field. Therefore, the Kramers-degenerated spin systems can be very perspective for measurement of a local magnetic field by the NV-based single-spin quantum magnetometer. Here, we are considering analytically the simplest Kramers-degenerated spin system NV+113C consisting of a single electron spin S=1 of the NV ?enter coupled by hyperfine interaction with a single nuclear spin I=1/2 of 13C atom disposed in arbitrary site of diamond lattice. Simple approximate analytical expressions are obtained for eigenvalues and eigenstates of the spin system.

  17. Further mapping of 10q26 supports strong association of HTRA1 polymorphisms with age-related macular degeneration

    Microsoft Academic Search

    Daniel Gibbs; Zhenglin Yang; Ryan Constantine; Xiang Ma; Nicola J. Camp; Xian Yang; Hayou Chen; Adam Jorgenson; Vincent Hau; Andrew DeWan; Jiexi Zeng; Jennifer Harmon; Jeanette Buehler; John M. Brand; Josephine Hoh; D. Joshua Cameron; Manjusha Dixit; Zongzhong Tong; Kang Zhang

    2008-01-01

    Age-related macular degeneration (AMD) is a complex disorder with genetic and environmental influences. The genetic influences affecting AMD are not well understood and few genes have been consistently implicated and replicated for this disease. A polymorphism (rs11200638) in a transcription factor binding site of the HTRA1 gene has been described, in previous reports, as being most significantly associated with AMD.

  18. A MODEL OF SPECTRAL FILTERING TO REDUCE PHOTOCHEMICAL DAMAGE IN AGE-RELATED MACULAR DEGENERATION

    PubMed Central

    Meyers, Sanford M; Ostrovsky, Mikhail A; Bonner, Robert F

    2004-01-01

    ABSTRACT Background/Purpose Cumulative sunlight exposure and cataract surgery are reported risk factors for advanced age-related macular degeneration (AMD). Laboratory studies suggest that accumulation and photochemical reactions of A2E (N-retinylidene-N-retinylethanolamine) and its epoxides, components of lipofuscin, are important in AMD. To relate this data to the clinical setting, we modeled the effects of macular irradiance and spectral filtering on production of A2E and reactive oxygen intermediates (ROIs) in pseudophakic eyes with a clear or “yellow” intraocular lens (IOL) and in phakic eyes. Methods We calculated relative changes of macular irradiance as a function of light (390 to 700 nm) intensity, pupil size, age, and lens status, and modeled resulting all-trans-retinal concentration and rates of production of A2E-related photochemicals and photon-induced ROIs in rods and retinal pigment epithelium (RPE). We compared these photoproducts following cataract surgery and IOL implantation with and without spectral sunglasses to normal age-related nuclear sclerotic lens changes. Results Following cataract and IOL surgery, all-trans-retinal and lipofuscin photochemistry would theoretically increase average generation of 1) A2E-related photochemicals, 2) ROI in rods and 3) ROI in RPE, respectively, 2.6-, 15- and 6.6-fold with a clear IOL, and 2.1-, 4.1- and 2.6 fold with a yellow IOL, but decrease approximately 30-, approximately 20-and 4-fold with a vermillion filter sunglass and clear IOL compared to an average 70 year old phakic eye. Conclusion Sunglasses that strongly decrease both deep blue light and rod photobleaching, while preserving photopic sensitivity and color perception, would provide upstream protection from potential photochemical damage in subjects at risk for AMD progression after cataract surgery. PMID:15747748

  19. Mechanisms of secondary degeneration after partial optic nerve transection

    PubMed Central

    Li, Hong-Ying; Ruan, Yi-Wen; Ren, Chao-Ran; Cui, Qi; So, Kwok-Fai

    2014-01-01

    Secondary degeneration occurs commonly in the central nervous system after traumatic injuries and following acute and chronic diseases, including glaucoma. A constellation of mechanisms have been shown to be associated with secondary degeneration including apoptosis, necrosis, autophagy, oxidative stress, excitotoxicity, derangements in ionic homeostasis and calcium influx. Glial cells, such as microglia, astrocytes and oligodendrocytes, have also been demonstrated to take part in the process of secondary injury. Partial optic nerve transection is a useful model which was established about 13 years ago. The merit of this model compared with other optic nerve injury models used for glaucoma study, including complete optic nerve transection model and optic nerve crush model, is the possibility to separate primary degeneration from secondary degeneration in location. Therefore, it provides a good tool for the study of secondary degeneration. This review will focus on the research progress of the mechanisms of secondary degeneration using partial optic nerve transection model. PMID:25206855

  20. Degenerate thermal pulses in AGB stars

    E-print Network

    Cheryl Frost; John Lattanzio; Peter Wood

    1998-03-05

    We report on the discovery of a new kind of thermal pulse in intermediate mass AGB stars. Deep dredge-up during normal thermal pulses on the AGB leads to the formation of a long, unburnt tail to the helium profile. Eventually the tail ignites under partially degenerate conditions producing a strong shell flash with very deep subsequent dredge-up. The carbon content of the intershell convective region (X_C ~ 0.6) is substantially higher than in a normal thermal pulse (X_C ~ 0.25) and about 4 times more carbon is dredged-up than in a normal pulse.

  1. Degenerate Fermi Gas of {sup 87}Sr

    SciTech Connect

    DeSalvo, B. J.; Yan, M.; Mickelson, P. G.; Martinez de Escobar, Y. N.; Killian, T. C. [Department of Physics and Astronomy, Rice University, Houston, Texas, 77251 (United States)

    2010-07-16

    We report quantum degeneracy in a gas of ultracold fermionic {sup 87}Sr atoms. By evaporatively cooling a mixture of spin states in an optical dipole trap for 10.5 s, we obtain samples well into the degenerate regime with T/T{sub F}=0.26{sub -0.06}{sup +0.05}. The main signature of degeneracy is a change in the momentum distribution as measured by time-of-flight imaging, and we also observe a decrease in evaporation efficiency below T/T{sub F{approx}}0.5.

  2. MRI and MR tractography in bilateral hypertrophic olivary degeneration.

    PubMed

    Sen, Debraj; Gulati, Yoginder S; Malik, Virender; Mohimen, Aneesh; Sibi, Eranki; Reddy, Deepak Chandra

    2014-10-01

    Hypertrophic olivary degeneration is a trans-synaptic neuronal degeneration associated with hypertrophy of the inferior olivary nucleus due to a lesion in the triangle of Guillain-Mollaret. Familiarity with this entity on magnetic resonance imaging (MRI) is essential to avoid other erroneous ominous diagnoses. We present a case of bilateral hypertrophic olivary degeneration and discuss the etiopathogenesis and MRI findings in this entity. The contributory role of MR tractography in the diagnosis is also highlighted. PMID:25489133

  3. Differential Modulation of Retinal Degeneration by Ccl2 and Cx3cr1 Chemokine Signalling

    PubMed Central

    Luhmann, Ulrich F. O.; Lange, Clemens A.; Robbie, Scott; Munro, Peter M. G.; Cowing, Jill A.; Armer, Hannah E. J.; Luong, Vy; Carvalho, Livia S.; MacLaren, Robert E.; Fitzke, Frederick W.; Bainbridge, James W. B.; Ali, Robin R.

    2012-01-01

    Microglia and macrophages are recruited to sites of retinal degeneration where local cytokines and chemokines determine protective or neurotoxic microglia responses. Defining the role of Ccl2-Ccr2 and Cx3cl1-Cx3cr1 signalling for retinal pathology is of particular interest because of its potential role in age-related macular degeneration (AMD). Ccl2, Ccr2, and Cx3cr1 signalling defects impair macrophage trafficking, but have, in several conflicting studies, been reported to show different degrees of age-related retinal degeneration. Ccl2/Cx3cr1 double knockout (CCDKO) mice show an early onset retinal degeneration and have been suggested as a model for AMD. In order to understand phenotypic discrepancies in different chemokine knockout lines and to study how defects in Ccl2 and/or Cx3cr1 signalling contribute to the described early onset retinal degeneration, we defined primary and secondary pathological events in CCDKO mice. To control for genetic background variability, we compared the original phenotype with that of single Ccl2, Cx3cr1 and Ccl2/Cx3cr1 double knockout mice obtained from backcrosses of CCDKO with C57Bl/6 mice. We found that the primary pathological event in CCDKO mice develops in the inferior outer nuclear layer independently of light around postnatal day P14. RPE and vascular lesions develop secondarily with increasing penetrance with age and are clinically similar to retinal telangiectasia not to choroidal neovascularisation. Furthermore, we provide evidence that a third autosomal recessive gene causes the degeneration in CCDKO mice and in all affected re-derived lines and subsequently demonstrated co-segregation of the naturally occurring RD8 mutation in the Crb1 gene. By comparing CCDKO mice with re-derived CCl2?/?/Crb1Rd8/RD8, Cx3cr1?/?/Crb1Rd8/RD8 and CCl2?/?/Cx3cr1?/?/Crb1Rd8/RD8 mice, we observed a differential modulation of the retinal phenotype by genetic background and both chemokine signalling pathways. These findings indicate that CCDKO mice are not a model of AMD, but a model for an inherited retinal degeneration that is differentially modulated by Ccl2-Ccr2 and Cx3cl1-Cx3cr1 chemokine signalling. PMID:22545116

  4. Thermodynamic functions of degenerate magnetized electron gas

    SciTech Connect

    Skobelev, V. V., E-mail: v.skobelev@inbox.ru [Moscow State Industrial University (Russian Federation)

    2011-11-15

    The Fermi energy, pressure, internal energy, entropy, and heat capacity of completely degenerate relativistic electron gas are calculated by numerical methods. It is shown that the maximum admissible magnetic field on the order of 10{sup 9} G in white dwarfs increases the pressure by a factor of 1.06 in the central region, where the electron concentration is {approx}10{sup 33} cm{sup -3}, while the equilibrium radius increases by approximately a factor of 1.03, which obviously cannot be observed experimentally. A magnetic field of {approx}10{sup 8} G or lower has no effect on the pressure and other thermodynamic functions. It is also shown that the contribution of degenerate electron gas to the total pressure in neutron stars is negligible compared to that of neutron gas even in magnetic fields with a maximum induction {approx}10{sup 17} G possible in neutron stars. The neutron beta-decay forbiddeness conditions in a superstrong magnetic field are formulated. It is assumed that small neutron stars have such magnetic fields and that pulsars with small periods are the most probable objects that can have super-strong magnetic fields.

  5. Emotion Regulation Deficits in Frontotemporal Lobar Degeneration and Alzheimer's Disease

    E-print Network

    Levenson, Robert W.

    . However, differences between the 3 groups emerged in the amount of emotional facial behavior expressedEmotion Regulation Deficits in Frontotemporal Lobar Degeneration and Alzheimer's Disease Madeleine instructed and spontaneous emotion regulation in patients with frontotemporal lobar degeneration (FTLD, N 32

  6. ANNULAR TEARS AND DISC DEGENERATION IN THE LUMBAR SPINE

    Microsoft Academic Search

    L. OSTI; B. VERNON-ROBERTS; R. MOORE; R. D. FRASER

    Histology suggested that peripheral tears were due to trauma rather than biochemical degradation, and that they developed independently of nuclear degeneration. The association of peripheral annular lesions with low back pain is uncertain but our study suggests that they may have a role in the pathogenesis of discogemc pain. The degenerating human intervertebral disc shows dehydration and fraying of the

  7. Hypertrophic Olivary Degeneration – A Report of Two Cases

    PubMed Central

    Sarawagi, Radha; Murugesan, Aravind

    2015-01-01

    Hypertrophic olivary degeneration (HOD) is seen following lesions in the Guillain–Mollaret triangle. This is unique because the inferior olivary nucleus hypertrophies following degeneration unlike the typical atrophy seen in other structures. We report two cases of HOD in two different clinical scenarios. PMID:25806143

  8. VISCOSITY SOLUTIONS TO DEGENERATE COMPLEX MONGE-AMP`ERE EQUATIONS

    E-print Network

    Boyer, Edmond

    VISCOSITY SOLUTIONS TO DEGENERATE COMPLEX MONGE-AMP`ERE EQUATIONS PHILIPPE EYSSIDIEUX, VINCENT an alternative approach based on the concept of viscosity solutions and compare systematically viscosity concepts PDE approach to second-order degenerate elliptic equations is the method of viscosity solutions

  9. Nmnat delays axonal degeneration caused by mitochondrial and oxidative stress

    PubMed Central

    Press, Craig; Milbrandt, Jeffrey

    2008-01-01

    Axonal degeneration is a prominent feature of many neurological disorders that are associated with mitochondrial dysfunction, including Parkinson’s disease (PD), motor neuron disease, and inherited peripheral neuropathies. It is now thought that axonal degeneration is an active process, due in large part to studies of the Wlds mutant mouse, which undergoes delayed Wallerian degeneration in response to axonal injury. Wlds mice also have slower axonal degeneration and disease progression in numerous models of neurodegenerative disease. The Wlds mutation results in the production of a chimeric protein that contains the full length coding sequence of nicotinamide mononucleotide adenylyltransferase 1 (Nmnat1), which alone is sufficient for axonal protection in vitro. To test the effects of increased Nmnat expression on axonal degeneration induced by mitochondrial dysfunction, we examined dorsal root ganglia (DRG) neurons treated with rotenone. Rotenone induced profound axonal degeneration in DRG neurons; however, this degeneration was delayed by expression of Nmnat. Nmnat-mediated protection resulted in decreased axonal accumulation and sensitivity to reactive oxygen species (ROS) but did not affect the change in the rate of rotenone-induced loss in neuronal ATP. Nmnat also prevented axonal degeneration caused by exposure to exogenous oxidants and reduced the level of axonal ROS after treatment with vincristine, further supporting the idea that Nmnat promotes axonal protection by mitigating the effects of ROS. PMID:18463239

  10. Optimal Control for Degenerate Parabolic Equations with Logistic Growth*

    E-print Network

    ) of the population to be trapped is the control in our problem. We can treat zero Dirichlet (z = 0) or Neumann (noOptimal Control for Degenerate Parabolic Equations with Logistic Growth* by Suzanne M. Lenhart 1 and Jiongmin Yong 2 Abstract. This paper considers the optimal control of a degenerate parabolic partial dif

  11. Optimal Control for Degenerate Parabolic Equations with Logistic Growth*

    E-print Network

    (x;t) of the population to be trapped is the control in our problem. We can treat zero Dirichlet (z = 0) or Neumann(no uxOptimal Control for Degenerate Parabolic Equations with Logistic Growth* by Suzanne M. Lenhart1 and Jiongmin Yong2 Abstract. This paper considers the optimal control of a degenerate parabolic partial dif

  12. Corticobasal degeneration: etiopathological significance of the cytoskeletal alterations

    Microsoft Academic Search

    K. Wakabayashi; K. Oyanagi; T. Makifuchi; F. Ikuta; A. Homma; Y. Homma; Y. Horikawa; S. Tokiguchi

    1994-01-01

    We have studied brain tissues from three patients with corticobasal degeneration (CBD) histologically, ultrastructurally and immunohistochemically. Ballooned neurons in the cerebral cortex and severe degeneration of the substantia nigra were observed in them all and weakly basophilic neurofibrillary tangles (NFTs) were distributed widely in the basal ganglia and brain stem. Ultrastructural examination demonstrated that the NFTs comprised characteristic 15-nm-wide straight

  13. Degenerations of flag and Schubert varieties to toric varieties

    Microsoft Academic Search

    N. Gonciulea; V. Lakshmibai

    1996-01-01

    In this paper, we prove the degenerations of Schubert varieties in a minusculeG\\/P, as well as the class of Kempf varieties in the flag varietySL(n)\\/B, to (normal) toric varieties. As a consequence, we obtain that determinantal varietes degenerate to (normal) toric varieties.

  14. Lies, Damn Lies, and Manchester's Recruiting Statistics: Degeneration as an \\

    Microsoft Academic Search

    Vanessa Heggie

    2008-01-01

    Few historians have attempted to discuss British medicine, health and welfare policies, or the biological sciences around 1900 without due reference to the concept of degeneration. Most tie public concern with degeneration to a specific set of military recruiting figures, which stated that of 11, 000 would-be volunteers in Manchester, 8,000 had to be turned away due to physical defects.

  15. Odor identification in frontotemporal lobar degeneration subtypes.

    PubMed

    Magerova, Hana; Vyhnalek, Martin; Laczo, Jan; Andel, Ross; Rektorova, Irena; Kadlecova, Alexandra; Bojar, Martin; Hort, Jakub

    2014-12-01

    Odor identification impairment is a feature of several neurodegenerative disorders. Although neurodegenerative changes in the frontotemporal lobar degeneration (FTLD) subtypes involve areas important for olfactory processing, data on olfactory function in these patients are limited. An 18-item, multiple-choice odor identification test developed at our memory clinic, the Motol Hospital smell test, was administered to 9 patients with behavioral variant frontotemporal dementia, 13 patients with the language variants, primary nonfluent aphasia (n = 7) and semantic dementia (n = 6), and 8 patients with progressive supranuclear palsy. Compared to the control group (n = 15), all FTLD subgroups showed significant impairment of odor identification (P < .05). The differences between the FTLD subgroups were not significant. No correlation between odor identification and neuropsychological tests results was found. Our data suggest that odor identification impairment is a symptom common to FTLD syndromes, and it seems to be based on olfactory structure damage rather than cognitive decline. PMID:24939002

  16. Anterior insula degeneration in frontotemporal dementia

    PubMed Central

    2010-01-01

    The human anterior insula is anatomically and functionally heterogeneous, containing key nodes within distributed speech–language and viscero-autonomic/social–emotional networks. The frontotemporal dementias selectively target these large-scale systems, leading to at least three distinct clinical syndromes. Examining these disorders, researchers have begun to dissect functions which rely on specific insular nodes and networks. In the behavioral variant of frontotemporal dementia, early-stage frontoinsular degeneration begets progressive “Salience Network” breakdown that leaves patients unable to model the emotional impact of their own actions or inactions. Ongoing studies seek to clarify local microcircuit- and cellular-level factors that confer selective frontoinsular vulnerability. The search for frontotemporal dementia treatments will depend on a rich understanding of insular biology and could help clarify specialized human language, social, and emotional functions. PMID:20512369

  17. [Forms of age-related macular degeneration].

    PubMed

    Schargus, M

    2015-04-01

    Age-related macular degeneration (AMD) is the major reason for blindness affecting about 50?% of blind people in Germany. Early forms of AMD with drusen and pigment epithelium changes can be detected in 20?% of patients over 65 years old. The dry form of AMD causes slow deterioration of visual acuity, which cannot currently be adequately treated. In contrast development of a choroidal neovascularization (CNV) membrane results in rapid visual loss which will become permanent if treatment is not started immediately. Using anti-vascular endothelial growth factor (VEGF) agents stabilization and improvement of visual acuity is possible. Special types of AMD, such as retinal angiomatous proliferation and polypoidal choroidal vasculopathy are much less common. The natural course of the diseases can be very different, end stages often result in scarring and anti-VEGF agents are only weakly effective. PMID:25837316

  18. Spectroscopic Temperature Determination of Degenerate Fermi Gases

    E-print Network

    Marijan Koštrun; Robin Côté

    2003-09-22

    We suggest a simple method for measuring the temperature of ultra-cold gases made of fermions. We show that by using a two-photon Raman probe, it is possible to obtain lineshapes which reveal properties of the degenerate sample, notably its temperature $T$. The proposed method could be used with identical fermions in different hyperfine states interacting via s-wave scattering or identical fermions in the same hyperfine state via p-wave scattering. We illustrate the applicability of the method in realistic conditions for $^6$Li prepared in two different hyperfine states. We find that temperatures down to 0.05 $T_{F}$ can be determined by this {\\it in-situ} method.

  19. Degenerate R-S perturbation theory

    NASA Technical Reports Server (NTRS)

    Hirschfelder, J. O.; Certain, P. R.

    1973-01-01

    A concise, systematic procedure is given for determining the Rayleigh-Schrodinger energies and wave functions of degenerate states to arbitrarily high orders even when the degeneracies of the various states are resolved in arbitrary orders. The procedure is expressed in terms of an iterative cycle in which the energy through the (2n+1)st order is expressed in terms of the partially determined wave function through the n-th order. Both a direct and an operator derivation are given. The two approaches are equivalent and can be transcribed into each other. The direct approach deals with the wave functions (without the use of formal operators) and has the advantage that it resembles the usual treatment of nondegenerate perturbations and maintains close contact with the basic physics. In the operator approach, the wave functions are expressed in terms of infinite order operators which are determined by the successive resolution of the space of the zeroth order functions.

  20. Cell degeneration and necrosis in experimental gliomas.

    PubMed Central

    Lantos, P. L.; Pilkington, G. J.

    1978-01-01

    Cell degeneration and necrosis in ethylnitrosourea-induced gliomas of rats were examined using light and electron microscopy. Two types of cell loss were observed: massive necrosis and individual cell death. Massive necrosis was influenced by the size, malignancy and histological type of the gliomas: it occurred most frequently in large, malignant pleomorphic gliomas and epindymomas. Proliferation of endothelial cells, narrowing of vascular lumina and degenerative changes affecting vessel walls were thought to be the major factors causing necrosis. Individual cell death occurred throughout the neoplasms irrespective of their size. Progressive degenerative changes, involving both the nucleus and cytoplasm, preceded cell death. Macrophages (both microglial and monocytic in origin). reacting astrocytes and, to a lesser extent, neoplastic glial cells engulfed and digested the necrotic cells and their remnants. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 PMID:638034

  1. Crystallization and collapse in relativistically degenerate matter

    SciTech Connect

    Akbari-Moghanjoughi, M. [International Centre for Advanced Studies in Physical Sciences and Institute for Theoretical Physics, Ruhr University Bochum, D-44780 Bochum, Germany and Department of Physics, Faculty of Sciences, Azarbaijan Shahid Madani University, 51745-406 Tabriz (Iran, Islamic Republic of)

    2013-04-15

    In this paper, it is shown that a mass density limit exists beyond which the relativistically degenerate matter would crystallize. The mass density limit, found here, is quite analogous to the mass limit predicted by Chandrasekhar for a type of compact stars called white dwarfs (M{sub Ch} Asymptotically-Equal-To 1.43 Solar Mass). In this study, the old problem of white dwarf core collapse, which has been previously investigated by Chandrasekhar using hydrostatic stability criteria, is revisited in the framework of the quantum hydrodynamics model by inspection of the charge screening at atomic scales in the relativistic degeneracy plasma regime taking into account the relativistic Fermi-Dirac statistics and electron interaction features such as the quantum statistical pressure, Coulomb attraction, electron exchange-correlation, and quantum recoil effects. It is revealed that the existence of ion correlation and crystallization of matter in the relativistically degenerate plasma puts a critical mass density limit on white dwarf core region. It is shown that a white dwarf star with a core mass density beyond this critical limit can undergo the spontaneous core collapse (SCC). The SCC phenomenon, which is dominantly caused by the electron quantum recoil effect (interference and localization of the electron wave function), leads to a new exotic state of matter. In such exotic state, the relativistic electron degeneracy can lead the white dwarf crystallized core to undergo the nuclear fusion and an ultimate supernova by means of the volume reduction (due to the enhanced compressibility) and huge energy release (due to the increase in cohesive energy), under the stars huge inward gravitational pressure. Moreover, it is found that the SCC phenomenon is significantly affected by the core composition (it is more probable for heavier plasmas). The critical mass density found here is consistent with the values calculated for core density of typical white dwarf stars.

  2. Potential regenerative treatment strategies for intervertebral disc degeneration in dogs

    PubMed Central

    2014-01-01

    Pain due to spontaneous intervertebral disc (IVD) disease is common in dogs. In chondrodystrophic (CD) dogs, IVD disease typically develops in the cervical or thoracolumbar spine at about 3–7 years of age, whereas in non-chondrodystrophic (NCD) dogs, it usually develops in the caudal cervical or lumbosacral spine at about 6–8 years of age. IVD degeneration is characterized by changes in the biochemical composition and mechanical integrity of the IVD. In the degenerated IVD, the content of glycosaminoglycan (GAG, a proteoglycan side chain) decreases and that of denatured collagen increases. Dehydration leads to tearing of the annulus fibrosus (AF) and/or disc herniation, which is clinically characterized by pain and/or neurological signs. Current treatments (physiotherapy, anti-inflammatory/analgesic medication, surgery) for IVD disease may resolve neurological deficits and reduce pain (although in many cases insufficient), but do not lead to repair of the degenerated disc. For this reason, there is interest in new regenerative therapies that can repair the degenerated disc matrix, resulting in restoration of the biomechanical function of the IVD. CD dogs are considered a suitable animal model for human IVD degeneration because of their spontaneous IVD degeneration, and therefore studies investigating cell-, growth factor-, and/or gene therapy-based regenerative therapies with this model provide information relevant to both human and canine patients. The aim of this article is to review potential regenerative treatment strategies for canine IVD degeneration, with specific emphasis on cell-based strategies. PMID:24387033

  3. Identification of genes associated with disc degeneration using bioinformatics.

    PubMed

    Ji, S-C; Han, N; Liu, Y; Li, G; Sun, Z; Li, Z

    2015-07-01

    Intervertebral disc degeneration is a common orthopedic disease that has been recognized as the major cause of low back pain. About 80% of the population is affected by this disease. We explored molecular mechanisms of disc degeneration and identified the genes associated with the disease. The transcription profile of GSE34095 was downloaded from Gene Expression Omnibus database with three degenerative disc samples and three healthy disc samples. Gene ontology and pathway enrichment analysis were performed. We constructed a protein-protein interaction (PPI) network and a transcription factor (TF) target network. Differentially expressed genes (DEGs) in normal and disc degeneration samples were identified including 243 up-regulated genes and 351 down-regulated genes. Meanwhile, seven Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were obtained by mapping the 594 DEGs to the KEGG and we found that the calcium signaling pathway was the most significant for developing disc degeneration. The pathways interaction network analysis showed that the adherens junction pathway interacted with other six pathways. In addition, the top five genes, FYN, PRKCD, YWHAB, YWHAZ and AR, with a high degree of interaction of 7, 4, 4, 4 and 4, respectively, were related to the disc degeneration in the PPI network. Furthermore, transcription factors including TFAP2A, E2F4, SP3 and AR had the potential to regulate disc degeneration through the mitogen-activated protein kinase, vascular endothelial growth factor and p53 pathways. The genes and pathways that we identified may be involved in disc degeneration. PMID:25801299

  4. Functionally rigid and degenerate molecular shuttles.

    PubMed

    Yoon, Il; Benítez, Diego; Zhao, Yan-Li; Miljani?, Ognjen S; Kim, Soo-Young; Tkatchouk, Ekaterina; Leung, Ken C-F; Khan, Saeed I; Goddard, William A; Stoddart, J Fraser

    2009-01-01

    The preparation and dynamic behavior of two functionally rigid and degenerate [2]rotaxanes (14 PF(6) and 24 PF(6)) in which a pi-electron deficient tetracationic cyclophane, cyclobis(paraquat-p-phenylene) (CBPQT(4+)) ring, shuttles back and forth between two pi-electron-rich naphthalene (NP) stations by making the passage along an ethynyl-phenylene-(PH)-ethynyl or butadiyne rod, are described. The [2]rotaxanes were synthesized by using the clipping approach to template-directed synthesis, and were characterized by NMR spectroscopic and mass spectrometric analyses. (1)H NMR spectra of both [2]rotaxanes show evidence for the formation of mechanically interlocked structures, resulting in the upfield shifts of the resonances for key protons on the dumbbell-shaped components. In particular, the signals for the peri protons on the NP units in the dumbbell-shaped components experienced significant upfield shifts at low temperatures, just as has been observed in the flexible [2]rotaxanes. Interestingly, the resonances for the same protons did not exhibit a significant upfield shift at 298 K, but rather only a modest shift. This phenomenon arises from the much reduced binding of the ethynyl-NP unit compared to the 1,5-dioxy-NP unit. This effect, in turn, increases the shuttling rate when compared to the 1,5-dioxy-NP-based rotaxane systems investigated previously. The kinetic and thermodynamic data of the shuttling behavior of the CBPQT(4+) ring between the NP units were obtained by variable-temperature NMR spectroscopy and using the coalescence method to calculate the free energies of activation (DeltaG(c) ( not equal)) of 9.6 and 10.3 kcal mol(-1) for 14 PF(6) and 24 PF(6), respectively, probed by using the rotaxane's alpha-bipyridinium protons. The solid-state structure of the free dumbbell-shaped compound (3) shows the fully rigid ethynyl-PH-ethynyl linker with a length (8.1 A) twice as long as that (3.8 A) of the butadiyne linker. Full-atomistic simulations were carried out with the DREIDING force field (FF) to probe the degenerate molecular shuttling processes, and afforded shuttling energy barriers (DeltaG( not equal)=10.4 kcal mol(-1) for 14 PF(6) and 24 PF(6)) that are in good agreement with the experimental values (DeltaG(c) ( not equal)=9.6 and 10.3 kcal mol(-1) for 14 PF(6) and 24 PF(6), respectively, probed by using their alpha-bipyridinium protons). PMID:19105194

  5. Deletion of autophagy inducer RB1CC1 results in degeneration of the retinal pigment epithelium.

    PubMed

    Yao, Jingyu; Jia, Lin; Khan, Naheed; Lin, Chengmao; Mitter, Sayak K; Boulton, Michael E; Dunaief, Joshua L; Klionsky, Daniel J; Guan, Jun-Lin; Thompson, Debra A; Zacks, David N

    2015-06-01

    Autophagy regulates cellular homeostasis and response to environmental stress. Within the retinal pigment epithelium (RPE) of the eye, the level of autophagy can change with both age and disease. The purpose of this study is to determine the relationship between reduced autophagy and age-related degeneration of the RPE. The gene encoding RB1CC1/FIP200 (RB1-inducible coiled-coil 1), a protein essential for induction of autophagy, was selectively knocked out in the RPE by crossing Best1-Cre mice with mice in which the Rb1cc1 gene was flanked with Lox-P sites (Rb1cc1(flox/flox)). Ex vivo and in vivo analyses, including western blot, immunohistochemistry, transmission electron microscopy, fundus photography, optical coherence tomography, fluorescein angiography, and electroretinography were performed to assess the structure and function of the retina as a function of age. Deletion of Rb1cc1 resulted in multiple autophagy defects within the RPE including decreased conversion of LC3-I to LC3-II, accumulation of autophagy-targeted precursors, and increased numbers of mitochondria. Age-dependent degeneration of the RPE occurred, with formation of atrophic patches, subretinal migration of activated microglial cells, subRPE deposition of inflammatory and oxidatively damaged proteins, subretinal drusenoid deposits, and occasional foci of choroidal neovascularization. There was secondary loss of photoreceptors overlying the degenerated RPE and reduction in the electroretinogram. These observations are consistent with a critical role of autophagy in the maintenance of normal homeostasis in the aging RPE, and indicate that disruption of autophagy leads to retinal phenotypes associated with age-related degeneration. PMID:26075877

  6. Simulating Four-Dimensional Simplicial Gravity using Degenerate Triangulations

    E-print Network

    S. Bilke; G. Thorleifsson

    1998-10-23

    We extend a model of four-dimensional simplicial quantum gravity to include degenerate triangulations in addition to combinatorial triangulations traditionally used. Relaxing the constraint that every 4-simplex is uniquely defined by a set of five distinct vertexes, we allow triangulations containing multiply connected simplexes and distinct simplexes defined by the same set of vertexes. We demonstrate numerically that including degenerated triangulations substantially reduces the finite-size effects in the model. In particular, we provide a strong numerical evidence for an exponential bound on the entropic growth of the ensemble of degenerate triangulations, and show that a discontinuous crumpling transition is already observed on triangulations of volume N_4 ~= 4000.

  7. Weakly dissipative solitons in dense relativistic-degenerate plasma

    NASA Astrophysics Data System (ADS)

    Ahmad, Saeed; Ata-ur-Rahman; Khan, S. A.

    2015-07-01

    We investigate the features of weakly nonlinear waves in a collisional dense plasma consisting of ultra-relativistic degenerate electrons and non-relativistic degenerate ions. In weak dissipation limit, the dynamics of low frequency nonlinear ion (solitary) wave is described by solving a damped Korteweg-deVries equation. The analytical and numerical analysis shows the existence of weakly dissipative solitons evolving with time. The characteristics of soliton evolution with plasma number density and slow ion-neutral collision rate are discussed with some detail. The relevance of the study with degenerate plasmas in ultra-dense astrophysical objects, particularly white dwarf stars is also pointed out.

  8. Quantitative Peptidomics of Purkinje Cell Degeneration Mice

    PubMed Central

    Berezniuk, Iryna; Sironi, Juan J.; Wardman, Jonathan; Pasek, Raymond C.; Berbari, Nicolas F.; Yoder, Bradley K.; Fricker, Lloyd D.

    2013-01-01

    Cytosolic carboxypeptidase 1 (CCP1) is a metallopeptidase that removes C-terminal and side-chain glutamates from tubulin. The Purkinje cell degeneration (pcd) mouse lacks CCP1 due to a mutation. Previously, elevated levels of peptides derived from cytosolic and mitochondrial proteins were found in adult pcd mouse brain, raising the possibility that CCP1 functions in the degradation of intracellular peptides. To test this hypothesis, we used a quantitative peptidomics technique to compare peptide levels in wild-type and pcd mice, examining adult heart, spleen, and brain, and presymptomatic 3 week-old amygdala and cerebellum. Contrary to adult mouse brain, young pcd brain and adult heart and spleen did not show a large increase in levels of intracellular peptides. Unexpectedly, levels of peptides derived from secretory pathway proteins were altered in adult pcd mouse brain. The pattern of changes for the intracellular and secretory pathway peptides in pcd mice was generally similar to the pattern observed in mice lacking primary cilia. Collectively, these results suggest that intracellular peptide accumulation in adult pcd mouse brain is a secondary effect and is not due to a role of CCP1 in peptide turnover. PMID:23593366

  9. Animal models of age related macular degeneration

    PubMed Central

    Pennesi, Mark E.; Neuringer, Martha; Courtney, Robert J.

    2013-01-01

    Age related macular degeneration (AMD) is the leading cause of vision loss of those over the age of 65 in the industrialized world. The prevalence and need to develop effective treatments for AMD has lead to the development of multiple animal models. AMD is a complex and heterogeneous disease that involves the interaction of both genetic and environmental factors with the unique anatomy of the human macula. Models in mice, rats, rabbits, pigs and non-human primates have recreated many of the histological features of AMD and provided much insight into the underlying pathological mechanisms of this disease. In spite of the large number of models developed, no one model yet recapitulates all of the features of human AMD. However, these models have helped reveal the roles of chronic oxidative damage, inflammation and immune dysregulation, and lipid metabolism in the development of AMD. Models for induced choroidal neovascularization have served as the backbone for testing new therapies. This article will review the diversity of animal models that exist for AMD as well as their strengths and limitations. PMID:22705444

  10. Degenerate crystals from colloidal dimers under confinement.

    PubMed

    Muangnapoh, Kullachate; Avendaño, Carlos; Escobedo, Fernando A; Liddell Watson, Chekesha M

    2014-12-28

    Colloidal aperiodic phases (i.e., entropy stabilized degenerate crystals, DCs) are realized via self-assembly of hollow fluorescent silica dimers under wedge-cell confinement. The dimer building blocks approximate two tangent spheres and their arrangements are studied via laser scanning confocal microscopy. In the DCs, the individual lobes tile a lattice and five distinct DC arrangements with square, triangular or rectangular layer symmetry are determined as a function of confinement height. Moreover, Monte Carlo simulations are used to construct the phase diagram for DCs up to two layer confinements and to analyze structural order in detail. Just as for spheres, the DC structural transitions under confinement are attributed to the ability or frustration to accommodate an integral number of particle layers between hard walls. Unlike spheres, dimers can also experience transitions involving changes in orientation. DCs are among the unconventional structures (e.g., semi-regular tilings, quasicrystals, plastic crystals) expected to enhance the properties of photonic solids. PMID:25366128

  11. [Criteria for the diagnosis of corticobasal degeneration].

    PubMed

    Shimohata, Takayoshi; Aiba, Ikuko; Nishizawa, Masatoyo

    2015-04-01

    Corticobasal degeneration (CBD) is a distinct neurodegenerative disorder characterized by widespread neuronal and glial accumulation of abnormally phosphorylated tau protein. Patients with CBD often present with corticobasal syndrome (CBS) showing impairment of the motor system, cognition, or both. Several studies demonstrate that they may also present with progressive supranuclear palsy syndrome (PSPS), aphasia, Alzheimer disease-like dementia, or behavioral changes, suggesting that CBS is merely one of the presenting phenotypes of CBD. Accurate diagnosis is important for future clinical trials using drugs aimed at modifying the underlying tau pathology. Although previous CBD diagnostic criteria reflected only CBS, Armstrong et al. proposed new diagnostic criteria for CBD in 2013 (Armstrong's criteria). The new criteria include 4 CBD phenotypes, including CBS, frontal behavioral-spatial syndrome (FBS), nonfluent/agrammatic variant of primary progressive aphasia (naPPA), and PSPS. These phenotypes were combined to create 2 sets of criteria: specific clinical research criteria for probable CBD (cr-CBD) and broader criteria for possible CBD that are more inclusive but have a higher probability of detecting other tau-based pathologies (p-CBD). However, two recent studies revealed that the sensitivity and specificity of these criteria were insufficient. Further refinement of the criteria is needed via biomarker research with prospective study designs. (Received August 19, 2014; Accepted December 26, 2014: Published April 1, 2015). PMID:25846600

  12. Statistical physics of age related macular degeneration

    NASA Astrophysics Data System (ADS)

    Family, Fereydoon; Mazzitello, K. I.; Arizmendi, C. M.; Grossniklaus, H. E.

    Age-related macular degeneration (AMD) is the leading cause of blindness beyond the age of 50 years. The most common pathogenic mechanism that leads to AMD is choroidal neovascularization (CNV). CNV is produced by accumulation of residual material caused by aging of retinal pigment epithelium cells (RPE). The RPE is a phagocytic system that is essential for renewal of photoreceptors (rods and cones). With time, incompletely degraded membrane material builds up in the form of lipofuscin. Lipofuscin is made of free-radical-damaged protein and fat, which forms not only in AMD, but also Alzheimer disease and Parkinson disease. The study of lipofuscin formation and growth is important, because of their association with cellular aging. We introduce a model of non-equilibrium cluster growth and aggregation that we have developed for studying the formation and growth of lipofuscin in the aging RPE. Our results agree with a linear growth of the number of lipofuscin granules with age. We apply the dynamic scaling approach to our model and find excellent data collapse for the cluster size distribution. An unusual feature of our model is that while small particles are removed from the RPE the larger ones become fixed and grow by aggregation.

  13. Quantitative peptidomics of Purkinje cell degeneration mice.

    PubMed

    Berezniuk, Iryna; Sironi, Juan J; Wardman, Jonathan; Pasek, Raymond C; Berbari, Nicolas F; Yoder, Bradley K; Fricker, Lloyd D

    2013-01-01

    Cytosolic carboxypeptidase 1 (CCP1) is a metallopeptidase that removes C-terminal and side-chain glutamates from tubulin. The Purkinje cell degeneration (pcd) mouse lacks CCP1 due to a mutation. Previously, elevated levels of peptides derived from cytosolic and mitochondrial proteins were found in adult pcd mouse brain, raising the possibility that CCP1 functions in the degradation of intracellular peptides. To test this hypothesis, we used a quantitative peptidomics technique to compare peptide levels in wild-type and pcd mice, examining adult heart, spleen, and brain, and presymptomatic 3 week-old amygdala and cerebellum. Contrary to adult mouse brain, young pcd brain and adult heart and spleen did not show a large increase in levels of intracellular peptides. Unexpectedly, levels of peptides derived from secretory pathway proteins were altered in adult pcd mouse brain. The pattern of changes for the intracellular and secretory pathway peptides in pcd mice was generally similar to the pattern observed in mice lacking primary cilia. Collectively, these results suggest that intracellular peptide accumulation in adult pcd mouse brain is a secondary effect and is not due to a role of CCP1 in peptide turnover. PMID:23593366

  14. Intervertebral disc degeneration: evidence for two distinct phenotypes

    PubMed Central

    Adams, Michael A; Dolan, Patricia

    2012-01-01

    We review the evidence that there are two types of disc degeneration. ‘Endplate-driven’ disc degeneration involves endplate defects and inwards collapse of the annulus, has a high heritability, mostly affects discs in the upper lumbar and thoracic spine, often starts to develop before age 30 years, usually leads to moderate back pain, and is associated with compressive injuries such as a fall on the buttocks. ‘Annulus-driven’ disc degeneration involves a radial fissure and/or a disc prolapse, has a low heritability, mostly affects discs in the lower lumbar spine, develops progressively after age 30 years, usually leads to severe back pain and sciatica, and is associated with repetitive bending and lifting. The structural defects which initiate the two processes both act to decompress the disc nucleus, making it less likely that the other defect could occur subsequently, and in this sense the two disc degeneration phenotypes can be viewed as distinct. PMID:22881295

  15. Age-Related Macular Degeneration: Current Treatment and Future Options

    PubMed Central

    Moutray, Tanya; Chakravarthy, Usha

    2011-01-01

    Age-related macular degeneration is the leading cause of visual impairment among older adults in the developed world. Epidemiological studies have revealed a number of genetic, ocular and environmental risk factors for this condition, which can be addressed by disease reduction strategies. We discuss the various treatment options for dry and exudative age-related macular degeneration available and explain how the recommended treatment depends on the exact type, location and extent of the degeneration. Currently, vascular endothelial growth factor (VEGF) inhibition therapy is the best available treatment for exudative age-related macular degeneration but is limited by the need for repeated intravitreal injections. The current treatment regime is being refined through research on optimal treatment frequency and duration and type of anti-VEGF drug. Different modes of drug delivery are being developed and in the future other methods of VEGF inhibition may be used. PMID:23251758

  16. Suppression of Density Fluctuations in a Quantum Degenerate Fermi Gas

    E-print Network

    Sanner, Christian Burkhard

    We study density profiles of an ideal Fermi gas and observe Pauli suppression of density fluctuations (atom shot noise) for cold clouds deep in the quantum degenerate regime. Strong suppression is observed for probe volumes ...

  17. Degenerate four-wave mixing in triply resonant Kerr cavities

    E-print Network

    Ramirez, David M.

    We demonstrate theoretical conditions for highly efficient degenerate four-wave mixing in triply resonant nonlinear (Kerr) cavities. We employ a general and accurate temporal coupled-mode analysis in which the interaction ...

  18. Double degenerates from the supernova Ia progenitor survey (SPY)

    Microsoft Academic Search

    C. Karl; R. Napiwotzki; U. Heber; T. Lisker; G. Nelemans; N. Christlieb; D. Reimers

    2002-01-01

    We report on follow-up observations of double degenerate (DD) white dwarfs\\u000afrom the Supernovae Ia Progenitor Survey (SPY). Orbital parameters of four\\u000asystems, including a massive short period system, are presented.

  19. Double degenerates from the supernova Ia progenitor survey (SPY)

    E-print Network

    C. Karl; R. Napiwotzki; U. Heber; T. Lisker; G. Nelemans; N. Christlieb; D. Reimers

    2002-09-30

    We report on follow-up observations of double degenerate (DD) white dwarfs from the Supernovae Ia Progenitor Survey (SPY). Orbital parameters of four systems, including a massive short period system, are presented.

  20. Stem cell regeneration of degenerated intervertebral discs: Current status

    Microsoft Academic Search

    Stephen M. Richardson; Judith A. Hoyland

    2008-01-01

    Low back pain (LBP) is one of the most common musculoskeletal conditions, and intervertebral disc (IVD) degeneration is associated\\u000a with most cases. Although many treatment options are available, they focus on the removal of symptoms rather than repair of\\u000a the degenerate tissue. However, there is a growing interest in the potential of cell-based tissue engineering strategies for\\u000a regeneration of the

  1. Tissue factor with age-related macular degeneration

    PubMed Central

    Wang, Guan-Feng; Zou, Xiu-Lan

    2012-01-01

    Wet age-related macular degeneration which incidence increases year by year is a blinding eye disease, but current clinical methods of treatment on this disease are limited and the outcome is not ideal. Recent studies have found abnormally high expression of tissue factors which are targets for the treatment of wet age-related macular degeneration to achieve a certain effect in the choroidal neovascularization. Related literatures are reviewed as following. PMID:23166874

  2. Electromagnetic solitons in degenerate relativistic electron–positron plasma

    NASA Astrophysics Data System (ADS)

    Berezhiani, V. I.; Shatashvili, N. L.; Tsintsadze, N. L.

    2015-06-01

    The existence of soliton-like electromagnetic (EM) distributions in a fully degenerate electron–positron plasma is studied applying relativistic hydrodynamic and Maxwell equations. For a circularly polarized wave it is found that the soliton solutions exist both in relativistic as well as nonrelativistic degenerate plasmas. Plasma density in the region of soliton pulse localization is reduced considerably. The possibility of plasma cavitation is also shown.

  3. Uniformly Levi degenerate CR manifolds; the 5 dimensional case

    Microsoft Academic Search

    Peter Ebenfelt

    1999-01-01

    In this paper, we consider real hypersurfaces $M$ in $\\\\Bbb C^3$ (or more generally, 5-dimensional CR manifolds of hypersurface type) at uniformly Levi degenerate points, i.e. Levi degenerate points such that the rank of the Levi form is constant in a neighborhood. We also require the hypersurface to satisfy a certain second order nondegeneracy condition (called 2-nondegeneracy) at the point.

  4. Degenerate Mode Birdcage Volume Coil for Sensitivity-Encoded Imaging

    E-print Network

    is degenerately tuned with both the standard homoge- neous mode and the first gradient mode of the birdcage coilDegenerate Mode Birdcage Volume Coil for Sensitivity- Encoded Imaging Fa-Hsuan Lin,1­3 Kenneth K. Kwong,2,3 Ing-Jye Huang,3,4 John W. Belliveau,2,3 and Lawrence L. Wald2,3* A volume birdcage coil

  5. Single-degenerate Type Ia Supernovae Are Preferentially Overluminous

    NASA Astrophysics Data System (ADS)

    Fisher, Robert; Jumper, Kevin

    2015-06-01

    Recent observational and theoretical progress has favored merging and helium-accreting sub-Chandrasekhar mass white dwarfs (WDs) in the double-degenerate and the double-detonation channels, respectively, as the most promising progenitors of normal Type Ia supernovae (SNe Ia). Thus the fate of rapidly accreting Chandrasekhar mass WDs in the single-degenerate channel remains more mysterious then ever. In this paper, we clarify the nature of ignition in Chandrasekhar-mass single-degenerate SNe Ia by analytically deriving the existence of a characteristic length scale which establishes a transition from central ignitions to buoyancy-driven ignitions. Using this criterion, combined with data from three-dimensional simulations of convection and ignition, we demonstrate that the overwhelming majority of ignition events within Chandrasekhar-mass WDs in the single-degenerate channel are buoyancy-driven, and consequently lack a vigorous deflagration phase. We thus infer that single-degenerate SNe Ia are generally expected to lead to overluminous 1991T-like SNe Ia events. We establish that the rates predicted from both the population of supersoft X-ray sources (SSSs) and binary population synthesis models of the single-degenerate channel are broadly consistent with the observed rates of overluminous SNe Ia, and suggest that the population of SSSs are the dominant stellar progenitors of SNe 1991T-like events. We further demonstrate that the single-degenerate channel contribution to the normal and failed 2002cx-like rates is not likely to exceed 1% of the total SNe Ia rate. We conclude with a range of observational tests of overluminous SNe Ia which will either support or strongly constrain the single-degenerate scenario.

  6. Prolonged prevention of retinal degeneration with retinylamine loaded nanoparticles.

    PubMed

    Puntel, Anthony; Maeda, Akiko; Golczak, Marcin; Gao, Song-Qi; Yu, Guanping; Palczewski, Krzysztof; Lu, Zheng-Rong

    2015-03-01

    Retinal degeneration impairs the vision of millions in all age groups worldwide. Increasing evidence suggests that the etiology of many retinal degenerative diseases is associated with impairment in biochemical reactions involved in the visual cycle, a metabolic pathway responsible for regeneration of the visual chromophore (11-cis-retinal). Inefficient clearance of toxic retinoid metabolites, especially all-trans-retinal, is considered responsible for photoreceptor cytotoxicity. Primary amines, including retinylamine, are effective in lowing the concentration of all-trans-retinal within the retina and thus prevent retina degeneration in mouse models of human retinopathies. Here we achieved prolonged prevention of retinal degeneration by controlled delivery of retinylamine to the eye from polylactic acid nanoparticles in Abca4(-/-)Rdh8(-/-) (DKO) mice, an animal model of Stargardt disease/age-related macular degeneration. Subcutaneous administration of the nanoparticles containing retinylamine provided a constant supply of the drug to the eye for about a week and resulted in effective prolonged prevention of light-induced retinal degeneration in DKO mice. Retinylamine nanoparticles hold promise for prolonged prophylactic treatment of human retinal degenerative diseases, including Stargardt disease and age-related macular degeneration. PMID:25617130

  7. The Gene for Slow Wallerian Degeneration ( Wld s ) Is Also Protective against Vincristine Neuropathy

    Microsoft Academic Search

    Min-Sheng Wang; Yue Wu; Deborah G. Culver; Jonathan D. Glass

    2001-01-01

    Neurological diseases are frequently associated with axonal degeneration, which leads to dysfunction though separation of neurons from their targets. The mechanisms of axonal degeneration are largely unknown and in many cases are independent of those occurring within cell bodies in neurodegenerative disorders. The Wlds mouse mutant demonstrates the unique phenotype of resistance to axonal degeneration after axotomy (slow Wallerian degeneration),

  8. Statins for age-related macular degeneration

    PubMed Central

    Gehlbach, Peter; Li, Tianjing; Hatef, Elham

    2013-01-01

    Background Age-related macular degeneration (AMD) is a progressive late onset disorder of the macula affecting central vision. Age-related macular degeneration is the leading cause of blindness in people over 65 years in industrialized countries (Congdon 2003). Recent epidemiologic, genetic and pathological evidence has shown AMD shares a number of risk factors with atherosclerosis, leading to the hypothesis that statins may exert protective effects in AMD. Objectives To examine the effectiveness of statins compared with other treatments, no treatment, or placebo in delaying the onset and/or progression of AMD. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 9), MEDLINE (January 1950 to September 2011), EMBASE (January 1980 to September 2011), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to September 2011), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 16 September 2011. Selection criteria We included randomized controlled trials (RCTs) that compared statins with other treatments, no treatment, or placebo in participants who were either susceptible to or diagnosed as having early stages of AMD. Data collection and analysis Two authors independently evaluated the search results against the selection criteria. Two Italian speaking colleagues extracted data. One author entered data. We did not perform a meta-analysis because only one completed RCT was identified. Main results Two studies met the selection criteria. One trial reported insufficient details to assess the risk of bias; the other trial is ongoing. Of the completed trial, the analyses of 30 participants did not show a statistically significant difference between the simvastatin and the placebo arm in visual acuity at three months of treatment (decimal visual acuity 0.21± 0.56 in simvastatin and 0.19± 0.40 in placebo arm) or 45 days after the completion of treatment (decimal visual acuity 0.20± 0.50 in simvastatin and 0.19± 0.48 in placebo arm). The lens and retina status were unchanged during and after the treatment period for both groups. Of the ongoing trial, the preliminary analyses of 42 participants who completed 12 months follow-up did not show a statistically significant difference between the simvastatin and the placebo arm in visual acuity, drusen score or visual function (effect estimates and confidence intervals were not available). We contacted the investigators and will update the review as data become available. Authors' conclusions Evidence from currently available RCTs was insufficient to conclude that statins have any role in preventing or delaying the onset or progression of AMD. PMID:22419318

  9. Neuroaxonal degeneration in sheep grazing Sorghum pastures.

    PubMed

    Bradley, G A; Metcalf, H C; Reggiardo, C; Noon, T H; Bicknell, E J; Lozano-Alarcon, F; Reed, R E; Riggs, M W

    1995-04-01

    During the fall of 1992, 250 (10%) of 2,500 Rambouilet cross feeder lambs grazing Sorghum bicolor developed neurologic signs including weakness, ataxia, head shaking, knuckling of the fetlocks, inability to rise, and opisthotonos. One hundred fifteen (46%) of the affected lambs died. Twenty of the surviving lambs exhibited residual neurologic signs of ataxia when stressed. At the same time, 275 (25%) of 1,100 ewes grazing a nearby sudex pasture (S. sudanese x S. bicolor) gave birth to lambs that were weak and unable to rise. Newborn lambs exhibited extensor rigidity and opisthotonos when assisted to a standing position. The dystocias that occurred were due to lambs with contracted limbs (arthrogryposis). All affected lambs died or were euthanized. Histologic examination of the brains of 3 feeder lambs and 9 newborn lambs revealed similar microscopic lesions. The predominant change was the presence of focal axonal enlargements (spheroids) in the proximal segments of axons, which were restricted to the nuclei of the medulla, cerebellum, and midbrain. In addition, the spinal cord contained spheroids in the ventral horn gray matter of the 6 newborns examined. Ultrastructurally, the spheroids were composed of aggregates of neurofilaments, mitochondria, vesicular bodies, and dense bodies bounded by a thin myelin sheath. There was mild gliosis in the more severely affected animals of both groups. There was minimal Wallerian degeneration in the white matter adjacent to affected nuclei in the brain and the ventromedial and dorsolateral funiculi of the spinal cord. This is the first detailed report of Sorghum toxicity in sheep. PMID:7619906

  10. Symmetric corticobasal degeneration (S-CBD)

    PubMed Central

    Hassan, Anhar; Boeve, Bradley F.; Whitwell, Jennifer L.; Jack, Clifford R; Parisi, Joseph E.; Dickson, Dennis W.; Josephs, Keith A.

    2010-01-01

    Background Corticobasal degeneration (CBD) is a neurodegenerative disease characterized pathologically by neuronal loss, gliosis and tau deposition in neocortex, basal ganglia and brainstem. Typical clinical presentation is known as corticobasal syndrome (CBS) and involves the core features of progressive asymmetric rigidity and apraxia, accompanied by other signs of cortical and extrapyramidal dysfunction. Asymmetry is also emphasized on neuroimaging. Objective To describe a series of cases of CBD with symmetric clinical features and to compare clinical and imaging features of these symmetric CBD cases (S-CBD) to typical cases of CBS with CBD pathology. Methods All cases of pathologically confirmed CBD from the Mayo Clinic Rochester database were identified. Clinical records were reviewed and quantitative volumetric analysis of symmetric atrophy on head MRI using atlas based parcellation was performed. Subjects were classified as S-CBD if no differences had been observed between right- and left-sided cortical or extrapyramidal signs or symptoms. S-CBD cases were compared to 10 randomly selected typical CBS cases. Results Five cases (2 female) met criteria for S-CBD. None had limb dystonia, myoclonus, apraxia or alien limb phenomena. S-CBD cases had significantly less asymmetric atrophy when compared with CBS cases (p=0.009); they were also younger at onset (median 61 versus 66 years, p<0.05) and death (67 versus 73 years, p<0.05). Family history was present in 40% of S-CBD cases. Conclusions CBD can have a symmetric presentation, clinically and radiologically, in which typical features of CBS, such as limb apraxia, myoclonus, dystonia and alien limb phenomenon, may be absent. PMID:20018548

  11. Criteria for the diagnosis of corticobasal degeneration

    PubMed Central

    Armstrong, Melissa J.; Lang, Anthony E.; Bak, Thomas H.; Bhatia, Kailash P.; Borroni, Barbara; Boxer, Adam L.; Dickson, Dennis W.; Grossman, Murray; Hallett, Mark; Josephs, Keith A.; Kertesz, Andrew; Lee, Suzee E.; Miller, Bruce L.; Reich, Stephen G.; Riley, David E.; Tolosa, Eduardo; Tröster, Alexander I.; Vidailhet, Marie; Weiner, William J.

    2013-01-01

    Current criteria for the clinical diagnosis of pathologically confirmed corticobasal degeneration (CBD) no longer reflect the expanding understanding of this disease and its clinicopathologic correlations. An international consortium of behavioral neurology, neuropsychology, and movement disorders specialists developed new criteria based on consensus and a systematic literature review. Clinical diagnoses (early or late) were identified for 267 nonoverlapping pathologically confirmed CBD cases from published reports and brain banks. Combined with consensus, 4 CBD phenotypes emerged: corticobasal syndrome (CBS), frontal behavioral-spatial syndrome (FBS), nonfluent/agrammatic variant of primary progressive aphasia (naPPA), and progressive supranuclear palsy syndrome (PSPS). Clinical features of CBD cases were extracted from descriptions of 209 brain bank and published patients, providing a comprehensive description of CBD and correcting common misconceptions. Clinical CBD phenotypes and features were combined to create 2 sets of criteria: more specific clinical research criteria for probable CBD and broader criteria for possible CBD that are more inclusive but have a higher chance to detect other tau-based pathologies. Probable CBD criteria require insidious onset and gradual progression for at least 1 year, age at onset ?50 years, no similar family history or known tau mutations, and a clinical phenotype of probable CBS or either FBS or naPPA with at least 1 CBS feature. The possible CBD category uses similar criteria but has no restrictions on age or family history, allows tau mutations, permits less rigorous phenotype fulfillment, and includes a PSPS phenotype. Future validation and refinement of the proposed criteria are needed. PMID:23359374

  12. The birth rate of supernovae from double-degenerate and core-degenerate systems

    NASA Astrophysics Data System (ADS)

    Meng, X.; Yang, W.

    2012-07-01

    Context. Some recent observations of the delay-time distribution (DTD) of Type Ia supernovae (SNe Ia) seem to uphold the double-degenerate (DD) scenario as the progenitor model of SNe Ia, but the core-degenerate (CD) scenario remains a strong competitor to the DD one. Aims: We investigate the effects of metallicity and the different treatments of common envelope (CE) on the DTD of SNe Ia by considering the DD and CD scenarios, and check the suggestion that the total mass of DD system is the main dependent variable of Phillips relation. Methods: We perform a series of Monte Carlo simulations based on a rapid binary evolution code and consider two treatments of CE evolution, i.e. ?-formalism and ?-algorithm. Results: We find that only when the ?-formalism is considered with a high CE ejection efficiency, may the shape of the DTD for DD systems be consistent with that derived observationally, i.e. a power law of ~t-1, while the value of the birth rate of SNe Ia marginally matches observations. For the ?-formalism with a low CE ejection efficiency and the ?-algorithm, neither the shape of the DTD nor the value of the birth rate can be compared with those of the observations. Metallicity may not have a significant influence on the shape of DTD, but a lower metallicity may lead to a slightly higher birth rate of SNe Ia by a factor of 2, especially for SNe Ia with long delay times. If the results for the single-degenerate (SD) channel are incorporated into those for the DTD, both the shape of DTD and its value may be closely consistent with observations for SNe Ia younger than 2.5 Gyr, and SD and DD channels provide comparable contributions to the total SNe Ia, while for SNe Ia with delay times longer than 2.5 Gyr, DD is the dominant channel and the birth rate is lower than that derived from observations by a factor up to about four. In addition, we calculate the evolutions of various integral parameters of DD systems, and do not find any one suitable to explain the correlation between the brightness of SNe Ia and its delay time. Moreover, there are three channels producing CD systems that may contribute a few SNe Ia, but the contribution of CD systems to the total SNe Ia is no more than 1%. Conclusions: There may be other channels or mechanisms contributing to SNe Ia with long delay times.

  13. Genetic Association Studies in Lumbar Disc Degeneration: A Systematic Review

    PubMed Central

    Eskola, Pasi J.; Lemmelä, Susanna; Kjaer, Per; Solovieva, Svetlana; Männikkö, Minna; Tommerup, Niels; Lind-Thomsen, Allan; Husgafvel-Pursiainen, Kirsti; Cheung, Kenneth M. C.; Chan, Danny

    2012-01-01

    Objective Low back pain is associated with lumbar disc degeneration, which is mainly due to genetic predisposition. The objective of this study was to perform a systematic review to evaluate genetic association studies in lumbar disc degeneration as defined on magnetic resonance imaging (MRI) in humans. Methods A systematic literature search was conducted in MEDLINE, MEDLINE In-Process, SCOPUS, ISI Web of Science, The Genetic Association Database and The Human Genome Epidemiology Network for information published between 1990–2011 addressing genes and lumbar disc degeneration. Two investigators independently identified studies to determine inclusion, after which they performed data extraction and analysis. The level of cumulative genetic association evidence was analyzed according to The HuGENet Working Group guidelines. Results Fifty-two studies were included for review. Forty-eight studies reported at least one positive association between a genetic marker and lumbar disc degeneration. The phenotype definition of lumbar disc degeneration was highly variable between the studies and replications were inconsistent. Most of the associations presented with a weak level of evidence. The level of evidence was moderate for ASPN (D-repeat), COL11A1 (rs1676486), GDF5 (rs143383), SKT (rs16924573), THBS2 (rs9406328) and MMP9 (rs17576). Conclusions Based on this first extensive systematic review on the topic, the credibility of reported genetic associations is mostly weak. Clear definition of lumbar disc degeneration phenotypes and large population-based cohorts are needed. An international consortium is needed to standardize genetic association studies in relation to disc degeneration. PMID:23185509

  14. Asymptotic Relation Between the Statistics of Degenerate and Non-Degenerate Wishart Ensembles

    E-print Network

    Tim Wirtz; Mario Kieburg; Thomas Guhr

    2015-04-13

    The correlated Wishart model provides the standard benchmark when analyzing time series. Unfortunately, the real case which is the most relevant one in applications, poses serious challenges for analytical calculations. Often these challenges are due to square root singularities which cannot be handled using common random matrix techniques. We present a new way to tackle this issue. For large but finite matrix dimensions, we show that statistical quantities in the bulk of the real correlated Wishart model with arbitrary empirical eigenvalues approach those of a real correlated Wishart model with matrix dimensions twice as large and doubly degenerate empirical eigenvalues. Our observation is based on an analytical study using supersymmetry and is confirmed by numerical simulations.

  15. Biologic Treatment of Mild and Moderate Intervertebral Disc Degeneration

    PubMed Central

    Vasiliadis, Elias S; Pneumaticos, Spyros G; Evangelopoulos, Demitrios S; Papavassiliou, Athanasios G

    2014-01-01

    Disc degeneration is the most common cause of back pain in adults and has enormous socioeconomic implications. Conservative management is ineffective in most cases, and results of surgical treatment have not yet reached desirable standards. Biologic treatment options are an alternative to the above conventional management and have become very attractive in recent years. The present review highlights the currently available biologic treatment options in mild and moderate disc degeneration, where a potential for regeneration still exists. Biologic treatment options include protein-based and cell-based therapies. Protein-based therapies involve administration of biologic factors into the intervertebral disc to enhance matrix synthesis, delay degeneration or impede inflammation. These factors can be delivered by an intradiscal injection, alone or in combination with cells or tissue scaffolds and by gene therapy. Cell-based therapies comprise treatment strategies that aim to either replace necrotic or apoptotic cells, or minimize cell death. Cell-based therapies are more appropriate in moderate stages of degenerated disc disease, when cell population is diminished; therefore, the effect of administration of growth factors would be insufficient. Although clinical application of biologic treatments is far from being an everyday practice, the existing studies demonstrate promising results that will allow the future design of more sophisticated methods of biologic intervention to treat intervertebral disc degeneration. PMID:25171110

  16. Review: Retinal degeneration: Focus on the unfolded protein response

    PubMed Central

    Gorbatyuk, Oleg

    2013-01-01

    Recently published literature has provided evidence that the unfolded protein response (UPR) is involved in the development of retinal degeneration. The scope of these studies encompassed diabetic retinopathy, retinopathy of prematurity, glaucoma, retinal detachment, light-induced retinal degeneration, age-related macular degeneration, and inherited retinal degeneration. Subsequent studies investigating the role of individual UPR markers in retinal pathogenesis and examining the therapeutic potential of reprogramming the UPR as a method for modulating the rate of retinal degeneration have been initiated. Manipulation of UPR markers has been made possible by the use of knockout mice, pharmacological agents, and viral vector-mediated augmentation of gene expression. Future research will aim at identifying specific inhibitors and/or inducers of UPR regulatory markers as well as expand the list of UPR-related animal models. Additionally, adeno-associated virus-mediated gene delivery is a safe and effective method for modulating gene expression, and thus is a useful research tool for manipulating individual UPR markers in affected retinas and a promising delivery vector for gene therapy in retinal degenerative disorders. PMID:24068865

  17. Wallerian degeneration: an emerging axon death pathway linking injury and disease.

    PubMed

    Conforti, Laura; Gilley, Jonathan; Coleman, Michael P

    2014-06-01

    Axon degeneration is a prominent early feature of most neurodegenerative disorders and can also be induced directly by nerve injury in a process known as Wallerian degeneration. The discovery of genetic mutations that delay Wallerian degeneration has provided insight into mechanisms underlying axon degeneration in disease. Rapid Wallerian degeneration requires the pro-degenerative molecules SARM1 and PHR1. Nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2) is essential for axon growth and survival. Its loss from injured axons may activate Wallerian degeneration, whereas NMNAT overexpression rescues axons from degeneration. Here, we discuss the roles of these and other proposed regulators of Wallerian degeneration, new opportunities for understanding disease mechanisms and intriguing links between Wallerian degeneration, innate immunity, synaptic growth and cell death. PMID:24840802

  18. Electromagnetic wave equations for relativistically degenerate quantum magnetoplasmas.

    PubMed

    Masood, Waqas; Eliasson, Bengt; Shukla, Padma K

    2010-06-01

    A generalized set of nonlinear electromagnetic quantum hydrodynamic (QHD) equations is derived for a magnetized quantum plasma, including collisional, electron spin- 1/2, and relativistically degenerate electron pressure effects that are relevant for dense astrophysical systems, such as white dwarfs. For illustrative purposes, linear dispersion relations are derived for one-dimensional magnetoacoustic waves for a collisionless nonrelativistic degenerate gas in the presence of the electron spin- 1/2 contribution and for magnetoacoustic waves in a plasma containing relativistically degenerate electrons. It is found that both the spin and relativistic degeneracy at high densities tend to slow down the magnetoacoustic wave due to the Pauli paramagnetic effect and relativistic electron mass increase. The present study outlines the theoretical framework for the investigation of linear and nonlinear behaviors of electromagnetic waves in dense astrophysical systems. The results are applied to calculate the magnetoacoustic speeds for both the nonrelativistic and relativistic electron degeneracy cases typical for white dwarf stars. PMID:20866534

  19. 'Photo-degeneration' of neurones after extracellular dye application.

    PubMed

    Picaud, S; Wunderer, H J; Franceschini, N

    1988-12-19

    Irradiation in the presence of a dye applied to the extracellular space was found to trigger neuronal degeneration in fly photoreceptor neurones. This phenomenon endowed the selected cells with a dark and fine-grained label such that they could be traced and scrutinized for synaptic specializations. It also initiated their phagocytotic removal from the neural network. Various states of degeneration fitting classical descriptions could be achieved by acting upon the light dose. The phenomenon seems to rely on photosensitization of the cell by the dye. The simplicity and precision with which this phenomenon can be induced makes 'photo-degeneration' an exciting prospective tool for combined anatomical and physiological studies on (natural) neural networks and may provide a new line of medical applications. PMID:3226611

  20. Nonplanar solitons in a degenerate multi-species plasma

    NASA Astrophysics Data System (ADS)

    Shah, M. G.; Mamun, A. A.; Hossen, M. R.

    2015-04-01

    The nonlinear propagation of cylindrical and spherical positron-acoustic solitary waves (PASWs) in an unmagnetized, collisionless, relativistic, degenerate plasma system that consists of nonrelativistic inertial cold positrons, relativistic degenerate electron and hot positron fluids, and positively-charged immobile ions has been investigated theoretically. By using a reductive perturbation technique, we derive the Korteweg-de Vries (K-dV) equation. The solitary wave solution has been numerically analyzed to comprehend the localized electrostatic disturbances. We observed that the effects of the degenerate pressure, relativity, and the number densities of inertial cold positrons, hot positrons, electrons, and positively-charged static ions notably modify the fundamental features of the cylindrical and the spherical PASWs. The implications of our results for dense plasmas in astrophysical compact objects ( e.g., non-rotating white dwarfs, neutron stars, etc.) are briefly discussed.

  1. Fundus autofluorescence imaging in age-related macular degeneration.

    PubMed

    Bat?o?lu, Figen; Demirel, Sibel; Özmert, Emin

    2015-01-01

    Fundus autofluorescence (FAF) is a noninvasive imaging technology that provides information on the distribution of lipofuscin within the retinal pigment epithelial cells. Progressive accumulation of lipofuscin within retinal pigment epithelial cells is involved in the pathogenesis of age-related macular degeneration (AMD). Fundus autofluorescence imaging using a confocal scanning laser ophthalmoscope is a useful technique to identify high-risk characteristics in patients with nonexudative AMD. It gives also some valuable knowledge and clues in differantial diagnosis of exudative age-related macular degeneration. This review comprises an introduction to fundus autofluorescence, a review of FAF imaging in AMD, and the recent classification of geographic atrophy (GA) and early AMD phenotypes by the Fundus Autofluorescence in Age-related Macular Degeneration Study. The association of phenotype and atrophy progression and choroidal neovascularization development are also summarized. PMID:23952079

  2. Degenerate Fermi gas in a combined harmonic-lattice potential

    SciTech Connect

    Blakie, P. B.; Bezett, A. [Jack Dodd Centre for Photonics and Ultra-Cold Atoms, Department of Physics, University of Otago, P.O. Box 56, Dunedin (New Zealand); Buonsante, P. [Jack Dodd Centre for Photonics and Ultra-Cold Atoms, Department of Physics, University of Otago, P.O. Box 56, Dunedin (New Zealand); Dipartimento di Fisica, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Turin (Italy)

    2007-06-15

    In this paper we derive an analytic approximation to the density of states for atoms in a combined optical lattice and harmonic trap potential as used in current experiments with quantum degenerate gases. We compare this analytic density of states to numerical solutions and demonstrate its validity regime. Our work explicitly considers the role of higher bands and when they are important in quantitative analysis of this system. Applying our density of states to a degenerate Fermi gas, we consider how adiabatic loading from a harmonic trap into the combined harmonic-lattice potential affects the degeneracy temperature. Our results suggest that occupation of excited bands during loading should lead to more favorable conditions for realizing degenerate Fermi gases in optical lattices.

  3. Quantization with maximally degenerate Poisson brackets: The harmonic oscillator!

    E-print Network

    Y. Nutku

    2003-06-09

    Nambu's construction of multi-linear brackets for super-integrable systems can be thought of as degenerate Poisson brackets with a maximal set of Casimirs in their kernel. By introducing privileged coordinates in phase space these degenerate Poisson brackets are brought to the form of Heisenberg's equations. We propose a definition for constructing quantum operators for classical functions which enables us to turn the maximally degenerate Poisson brackets into operators. They pose a set of eigenvalue problems for a new state vector. The requirement of the single valuedness of this eigenfunction leads to quantization. The example of the harmonic oscillator is used to illustrate this general procedure for quantizing a class of maximally super-integrable systems.

  4. Prevalence of Facet Joint Degeneration in Association with Intervertebral Joint Degeneration in a Sample of Organ Donors

    PubMed Central

    Muehleman, Carol; Li, Jun; Abe, Yumiko; Masuda, Koichi

    2011-01-01

    Among the most common causes of low back pain are strain on the muscles and ligaments associated with the spine, degeneration of the intervertebral discs (IVD), and osteoarthritis of the facet joints. It is not clear, however, how these latter two conditions are related to each other in terms of their development during a patient’s lifetime. The facet joint is the sole synovial joint of the spine but because it is difficult to image its degenerative history as well as its relationship to other degenerative factors within the spine remain elusive. We compared the gross and histologic characteristics of the lumbar spine from a sample of organ donors to the integrity of their associated IVDs as assessed through magnetic resonance imaging. In our study sample, we found that facet joint degeneration was common, occurring as early as 15 years of age, while the IVD could still remain intact. Facet degeneration was more severe at the L4/5 level and progressed along with IVD degeneration with age. Because such early degenerative changes in the facet joint are somewhat surprising, degeneration of this joint should not be overlooked when assessing OA of the spine and causes of lower back pain. PMID:21360583

  5. Degeneration and the origins of Mexico's war on drugs.

    PubMed

    Campos, Isaac

    2010-01-01

    In the early twentieth century, the concept of “degeneration” helped to turn “drugs” into a problem of national importance in Mexico. By invoking this concept, Mexico's sanitary authorities secured provisions in the Constitution of 1917 which specifically authorized a newly constituted Department of Public Sanitation to lead a nation-wide campaign against drug abuse. That Department then inaugurated Mexico's modern war on drugs when, in 1920, it declared a law governing the import and distribution of the opiates, cocaine, and marijuana nationwide. This essay examines the idea of degeneration and how it came to play this crucial role in the foundation of Mexico's modern war on drugs. PMID:20821890

  6. Mouse models for studies of retinal degeneration and diseases

    PubMed Central

    Chang, Bo

    2013-01-01

    Summary Mouse models, with their well-developed genetics and similarity to human physiology and anatomy, serve as powerful tools with which to investigate the etiology of human retinal degeneration. Mutant mice also provide reproducible, experimental systems for elucidating pathways of normal development and function. Here, I describe the tools used in the discoveries of many retinal degeneration models, including indirect ophthalmoscopy (to look at the fundus appearance), fundus photography and fluorescein angiography (to document the fundus appearance), electroretinography (to check retinal function) as well as the heritability test (for genetic characterization). PMID:23150358

  7. Key emerging issues in progressive supranuclear palsy and corticobasal degeneration.

    PubMed

    Josephs, Keith A

    2015-03-01

    It has been approximately 50 years since neurologists were introduced to the entities, "progressive supranuclear palsy" and "corticobasal degeneration". Since the two seminal publications, there have been significant advancements in our understanding of these two neurodegenerative diseases, particularly the fact that both are associated with tau. Recent advances over the past 3 years that are notable to the field are discussed in this review that covers clinical diagnosis, pathological features, neuroimaging and CSF biomarkers, genetic associations and clinical trials related to progressive supranuclear palsy and corticobasal degeneration. PMID:25701010

  8. Detection of cGMP in the degenerating retina.

    PubMed

    Michalakis, Stylianos; Xu, Jianhua; Biel, Martin; Ding, Xi-Qin

    2013-01-01

    Cyclic guanosine 3'-5'-monophosphate (cGMP) plays a key role in the physiological process of light detection in photoreceptor cells of the retina. However, there is also growing evidence that cGMP may be critically involved in some pathophysiological processes of the retina since degenerating photoreceptors in mouse models of retinitis pigmentosa and achromatopsia accumulate high levels of cGMP. Here, we describe methods that allow the detection, subcellular localization, and quantification of cGMP in the retina and propose that cGMP accumulation can be used as a biomarker for photoreceptor degeneration. PMID:23709038

  9. Extended Hellmann-Feynman theorem for degenerate eigenstates

    NASA Astrophysics Data System (ADS)

    Zhang, G. P.; George, Thomas F.

    2004-04-01

    In a previous paper, we reported a failure of the traditional Hellmann-Feynman theorem (HFT) for degenerate eigenstates. This has generated enormous interest among different groups. In four independent papers by Fernandez, by Balawender, Hola, and March, by Vatsya, and by Alon and Cederbaum, an elegant method to solve the problem was devised. The main idea is that one has to construct and diagonalize the force matrix for the degenerate case, and only the eigenforces are well defined. We believe this is an important extension to HFT. Using our previous example for an energy level of fivefold degeneracy, we find that those eigenforces correctly reflect the symmetry of the molecule.

  10. Exact null controllability of degenerate evolution equations with scalar control

    SciTech Connect

    Fedorov, Vladimir E; Shklyar, Benzion

    2012-12-31

    Necessary and sufficient conditions for the exact null controllability of a degenerate linear evolution equation with scalar control are obtained. These general results are used to examine the exact null controllability of the Dzektser equation in the theory of seepage. Bibliography: 13 titles.

  11. Treatment of dry age-related macular degeneration with dobesilate

    PubMed Central

    Cuevas, P; Outeiriño, L A; Angulo, J; Giménez-Gallego, G

    2012-01-01

    The authors present anatomical and functional evidences of dry age-macular degeneration improvement, after intravitreal treatment with dobesilate. Main outcomes measures were normalisation of retinal structure and function, assessed by optical coherence tomography, fundus-monitored microperimetry, electrophysiology and visual acuity. The effect might be related to the normalisation of the outer retinal architecture. PMID:22729337

  12. E1-DEGENERATION OF THE IRREGULAR HODGE FILTRATION OF

    E-print Network

    Sabbah, Claude

    E1-DEGENERATION OF THE IRREGULAR HODGE FILTRATION OF EXPONENTIALLY TWISTED MIXED HODGE MODULES, we associate to these data a filtration (the irregular Hodge fil- tration) on the exponentially by projective morphisms, duality, etc.). In particular, the behaviour of the Hodge filtration is well

  13. Inflammatory mediators in intervertebral disk degeneration and discogenic pain.

    PubMed

    Wuertz, Karin; Haglund, Lisbet

    2013-06-01

    Although degeneration of the intervertebral disk has historically been described as a misbalance between anabolic and catabolic factors, the role of inflammatory mediators has long been neglected. However, past research clearly indicates that inflammatory mediators such as interleukin (IL)-1?, IL-6, IL-8 and tumor necrosis factor-? are expressed at higher levels in "diseased" intervertebral disks. Both disk cells as well as invading macrophages can be the source of the detected cytokines. Importantly, occurrence of inflammatory mediators in the disk can worsen the progress of degeneration by inducing the expression of matrix degrading enzymes as well as by inhibiting extracellular matrix synthesis. In addition, inflammatory mediators play a crucial role in pain development during intervertebral disk herniation (i.e., sciatica) and disk degeneration (i.e., discogenic pain). This review provides information on the most relevant inflammatory mediators during different types of disk diseases and explains how these factors can induce disk degeneration and the development of discogenic and sciatic/radiculopathic pain. PMID:24436868

  14. Protein tyrosine phosphatase inhibition reduces degeneration of dopaminergic substantia nigra

    E-print Network

    Harkema, Susan

    Protein tyrosine phosphatase inhibition reduces degeneration of dopaminergic substantia nigra of injured adult dopaminergic substantia nigra pars compacta neurons can be promoted by various neurotrophic bisperoxo(1,10-phenanthroline)oxovanadate (V) (bpV(phen))], for 14 days close to the substantia nigra

  15. Degenerate and Stable Yang-Mills-Higgs Pairs

    E-print Network

    Zhi Hu; Sen Hu

    2015-02-09

    In this paper, we introduce some notions on the pair consisting of a Chern connection and a Higgs field closely related to the first and second variation of Yang-Mills- Higgs functional, such as strong Yang-Mills-Higgs pair, degenerate Yang-Mills-Higgs pair, stable Yang-Mills-Higgs pair. We investigate some properties of such pairs.

  16. Speech and Language Findings Associated with Paraneoplastic Cerebellar Degeneration

    ERIC Educational Resources Information Center

    Paslawski, Teresa; Duffy, Joseph R.; Vernino, Steven

    2005-01-01

    Paraneoplastic cerebellar degeneration (PCD) is an autoimmune disease that can be associated with cancer of the breast, lung, and ovary. The clinical presentation of PCD commonly includes ataxia, visual disturbances, and dysarthria. The speech disturbances associated with PCD have not been well characterized, despite general acceptance that…

  17. Cognitive Impairment in the Lateralized Phenotype of Corticobasal Degeneration

    Microsoft Academic Search

    Rita Moretti; Paola Torre; Rodolfo M. Antonello; Tatiana Cattaruzza; Giuseppe Cazzato

    2005-01-01

    Corticobasal degeneration (CBD) is a rare disorder, which normally includes a combination of neurobehavioural features, movement disorders and other manifestations. It is now recognized that CBD patients usually present with two phenotypes: the lateralized phenotype and the dementia phenotype. The aim of our work was to determine the nature and the progression of cognitive and behavioural impairment in 10 lateralized

  18. Complete population transfer in degenerate n-state atoms

    E-print Network

    J. H. McGuire; Kh. Kh. Shakov; Kh. Yu. Rakhimov

    2003-06-11

    We find a set of conditions to achieve complete population transfer, via coherent population trapping, from an initial state to a designated final state at a designated time in a degenerate n-state atom, where the transitions are caused by an external interaction.

  19. Hedgehog signalling controls eye degeneration in blind cavefish

    Microsoft Academic Search

    Yoshiyuki Yamamoto; David W. Stock; William R. Jeffery

    2004-01-01

    Hedgehog (Hh) proteins are responsible for critical signalling events during development but their evolutionary roles remain to be determined. Here we show that hh gene expression at the embryonic midline controls eye degeneration in blind cavefish. We use the teleost Astyanax mexicanus, a single species with an eyed surface-dwelling form (surface fish) and many blind cave forms (cavefish), to study

  20. PGC-1? Regulation of Mitochondrial Degeneration in Experimental Diabetic Neuropathy

    PubMed Central

    Choi, Joungil; Chandrasekaran, Krish; Inoue, Tatsuya; Muragundla, Anjaneyulu; Russell, James W.

    2014-01-01

    Mitochondrial degeneration is considered to play an important role in the development of diabetic peripheral neuropathy in humans. Mitochondrial degeneration and the corresponding protein regulation associated with the degeneration were studied in an animal model of diabetic neuropathy. PGC-1? and its-regulated transcription factors including TFAM and NRF1, which are master regulators of mitochondrial biogenesis, are significantly downregulated in streptozotocin diabetic dorsal root ganglion (DRG) neurons. Diabetic mice develop peripheral neuropathy, loss of mitochondria, decreased mitochondrial DNA content and increased protein oxidation. Importantly, this phenotype is exacerbated in PGC-1? (?/?) diabetic mice, which develop a more severe neuropathy with reduced mitochondrial DNA and a further increase in protein oxidation. PGC-1? (?/?) diabetic mice develop an increase in total cholesterol and triglycerides, and a decrease in TFAM and NRF1 protein levels. Loss of PGC-1? causes severe mitochondrial degeneration with vacuolization in DRG neurons, coupled with reduced state 3 and 4 respiration, reduced expression of oxidative stress response genes and an increase in protein oxidation. In contrast, overexpression of PGC-1? in cultured adult mouse neurons prevents oxidative stress associated with increased glucose levels. The study provides new insights into the role of PGC-1? in mitochondrial regeneration in peripheral neurons and suggests that therapeutic modulation of PGC-1? function may be an attractive approach for treatment of diabetic neuropathy. PMID:24423644

  1. A model to study the disc degeneration process.

    PubMed

    Natarajan, R N; Ke, J H; Andersson, G B

    1994-02-01

    Initiation and propagation of different types of events that lead to disc degeneration and the effect of the degenerating process on the disc mechanical performance is difficult to study by experimental methods. This study aimed to develop and use a finite element model of a motion segment without posterior elements to study the disc degeneration process. The model was used to study the development of anular tears, nuclear clefts, and endplate fractures and subsequent propagation of these degenerative processes due to compressive and bending loads. The analyses showed that the failure always started at the end plates indicating that they are the weak link in the body-disc-body unit. The analyses also showed that anular injuries are unlikely to be produced by pure compressive loads. The model predicted that it would require a larger extension moment as compared to flexion moment to initiate and propagate failure in a motion segment, which leads to the conclusion that the motion segment is stiffer in extension. The model also suggested that the presence of discrete peripheral tears in the anulus fibrosus may have a role in the formation of concentric anular tears and in accelerating the degenerating process of the disc. PMID:8171355

  2. The Experience of Age-Related Macular Degeneration

    ERIC Educational Resources Information Center

    Wong, Elaine Y. H.; Guymer, Robyn H.; Hassell, Jennifer B.; Keeffe, Jill E.

    2004-01-01

    This qualitative article describes the impact of age-related macular degeneration (ARMD) among 15 participants: how a person makes sense of ARMD, the effect of ARMD on the person's quality of life, the psychological disturbances associated with the limitations of ARMD, and the influence of ARMD on social interactions. Such in-depth appreciation of…

  3. The ground state of dilute Tm systems is degenerate

    Microsoft Academic Search

    M. Baliña; A. A. Aligia

    1990-01-01

    The ground state of the appropriate generalization of the impurity Anderson model for valence fluctuations between two realistic Tm+2 and Tm+3 configurations is obtained, in the narrowband limit, using the Lanczos' method. This limit describes the strong-coupling fixed point of renormalization group treatments for intermediate valence and Kondo impurities. The resulting ground state is highly degenerate and contains states of

  4. Wallerian Degeneration in the Optic Nerve of the Rabbit

    Microsoft Academic Search

    Aijaz Ahmed Khan

    2004-01-01

    Progressive anterograde axonal degeneration is known to follow after transection of the axon from the soma, which to some extent correlates with the passage of time after the lesion. However, the minimum time required for such changes to begin remains unresolved. In this study, 20 young adult rabbits of either sex underwent experimental monocular enucleation (left eye) under general anaesthesia.

  5. Distal embolization from medial cystic degeneration of the popliteal artery.

    PubMed

    Richards, J; Stuart, W P

    2011-08-01

    This is the first reported case of medial cystic degeneration of the popliteal artery presenting as distal embolization and contains a high-definition photo of the cyst in situ. Duplex ultrasound and magnetic resonance angiography are useful adjuncts to diagnosis. Based on the published literature, resection and interposition grafting appears to be the most efficacious treatment modality. PMID:21873730

  6. Degenerating Y chromosome of Drosophila miranda: a trap for retrotransposons.

    PubMed Central

    Steinemann, M; Steinemann, S

    1992-01-01

    In Drosophila miranda, the larval cuticle protein (Lcp) genes are located on the X2 and Y chromosomes, while in other Drosophila species the Lcp genes are inherited on the autosomes. We chose the D. miranda species as a model system to analyze the molecular bases of Y chromosome degeneration, a phenomenon observed in many species. DNA sequence analysis of the Y chromosomal Lcp gene locus reveals dense clustering of trapped retrotransposons. Once inserted at the Y chromosomal location they cannot easily be eliminated by unequal crossing-over, as recombination is a rare event in Drosophila males. In addition, we have uncovered an example of a completely inactive allele on the degenerating Y chromosome. The existence of such inactive Y-specific alleles was originally predicted in H. J. Muller's model for Y chromosome degeneration. We demonstrate that the Y chromosomal Lcp4 allele is no longer transcribed. From the divergence in DNA sequence organization of former homologous chromosome regions we conclude that changes in chromosome structure and destruction of genetic activity in degenerating Y chromosomes are based on one major mechanism, which operates by means of transposable elements. Images PMID:1323846

  7. Clinical, Imaging and Electrophysiological Studies of Corticobasal Degeneration

    Microsoft Academic Search

    Kai-Ju Huang; Ming-Kuei Lu; Albert Kao; Chon-Haw Tsai

    Corticobasal degeneration (CBD) is a rare neurodegenerative disorder characterized by distinc- tive clinical manifestations including asymmetric akinetic-rigid syndrome and higher cortical dysfunctions. We characterized the clinical, electrophysiological and imaging presentations in four patients with CBD. All patients exhibited unilateral hand dystonia, rigidity and apraxia, but showed no significant response to lev- odopa therapy. Surface electromyography demonstrated short duration and stimulus-sensitive

  8. Gestural Imitation and Limb Apraxia in Corticobasal Degeneration

    ERIC Educational Resources Information Center

    Salter, Jennifer E.; Roy, Eric A.; Black, Sandra E.; Joshi, Anish; Almeida, Quincy

    2004-01-01

    Limb apraxia is a common symptom of corticobasal degeneration (CBD). While previous research has shown that individuals with CBD have difficulty imitating transitive (tool-use actions) and intransitive non-representational gestures (nonsense actions), intransitive representational gestures (actions without a tool) have not been examined. In the…

  9. A New Merging Double Degenerate Binary in the Solar Neighborhood

    E-print Network

    Debes, John H; Tremblay, Pier-Emmanuel; López-Morales, Mercedes; Anglada-Escudé, Guillem; Napiwotzki, Ralf; Osip, David; Weinberger, Alycia

    2015-01-01

    Characterizing the local space density of double degenerate binary systems is a complementary approach to broad sky surveys of double degenerates to determine the expected rates of white dwarf binary mergers, in particular those that may evolve into other observable phenomena such as extreme helium stars, Am CVn systems, and supernovae Ia. However, there have been few such systems detected in local space. We report here the discovery that WD 1242$-$105, a nearby bright WD, is a double-line spectroscopic binary consisting of two degenerate DA white dwarfs of similar mass and temperature, despite it previously having been spectroscopically characterized as a single degenerate. Follow-up photometry, spectroscopy, and trigonometric parallax have been obtained in an effort to determine the fundamental parameters of each component of this system. The binary has a mass ratio of 0.7 and a trigonometric parallax of 25.5 mas, placing it at a distance of 39 pc. The system's total mass is 0.95 M$_\\odot$ and has an orbita...

  10. ERYTHROCYTE DEGENERATION IN THE ATLANTIC HERRING, CLUPBA HARENGUS HARENGUS L.

    E-print Network

    ERYTHROCYTE DEGENERATION IN THE ATLANTIC HERRING, CLUPBA HARENGUS HARENGUS L. STUART W. SHERBURNE blood of herring from Boothbay Harbor, Maine, and from Passamaquoddy Bay at Deer Island, N.R, Canada, in 1969. Except in one instance, when inclusions occurred in herring from water of 2°C, all herring from

  11. The Effects of Simulated Microgravity on Intervertebral Disc Degeneration

    PubMed Central

    Jin, Li; Feng, Gang; Reames, Davis L; Shimer, Adam L; Shen, Francis H; Li, Xudong

    2012-01-01

    BACKGROUND CONTEXT Astronauts experience back pain, particularly low back pain, during and after spaceflight. Recent studies have described histological and biochemical changes in rat intervertebral discs after space travel, but there is still no in vitro model to investigate the effects of microgravity on disc metabolism. PURPOSE To study the effects of microgravity on disc degeneration and to establish an in vitro simulated microgravity study model STUDY DESIGN Discs were cultured in static and rotating conditions in bioreactor, and the characteristics of disc degeneration were evaluated METHODS The mice discs were cultured in a rotating wall vessel bioreactor where the microgravity condition was simulated. Intervertebral discs were cultured in static and microgravity condition. Histology, biochemistry, and immunohistochemical assays were performed to evaluate the characteristics of the discs in microgravity condition. RESULTS Intervertebral discs cultured in rotating bioreactors were found to develop changes of disc degeneration manifested by reduced red Safranin-o staining within the annulus fibrosus, downregulated GAG content and GAG/Hypro ratio, increased MMP-3 expression, and upregulated apoptosis. CONCLUSIONS We conclude that simulated microgravity induces the molecular changes of disc degeneration. The rotating bioreactor model will provide a foundation to investigate the effects of microgravity on disc metabolism. PMID:23537452

  12. Blood Flow Magnetic Resonance Imaging of Retinal Degeneration

    E-print Network

    Duong, Timothy Q.

    Blood Flow Magnetic Resonance Imaging of Retinal Degeneration Yingxia Li,1 Haiying Cheng,1 Qiang. Duong1,2,3,4,5,6,7 PURPOSE. This study aims to investigate quantitative basal blood flow as well as hypercapnia- and hyperoxia-induced blood flow changes in the retinas of the Royal College of Surgeons (RCS

  13. Quantum error correction with degenerate codes for correlated noise

    SciTech Connect

    Chiribella, Giulio [Perimeter Institute for Theoretical Physics, 31 Caroline St. North, Waterloo, Ontario N2L 2Y5 (Canada); Dall'Arno, Michele; D'Ariano, Giacomo Mauro; Macchiavello, Chiara; Perinotti, Paolo [Quit group, Dipartimento di Fisica 'A. Volta', via Bassi 6, I-27100 Pavia (Italy); INFN Sezione di Pavia, via Bassi 6, I-27100 Pavia (Italy)

    2011-05-15

    We introduce a quantum packing bound on the minimal resources required by nondegenerate error-correction codes for any kind of noise. We prove that degenerate codes can outperform nondegenerate ones in the presence of correlated noise, by exhibiting examples where the quantum packing bound is violated.

  14. A degenerate central limit theorem for single resource loss systems

    Microsoft Academic Search

    Christine Fricker; Philippe Robert; Danielle Tibi

    2003-01-01

    Loss networks in heavy traffic under Kelly's scaling are\\u000aanalyzed. In the case of a single node and $R$ classes of calls,\\u000aa degenerate diffusion approximation theorem around the\\u000acorresponding fluid limit in an $({R-1})$-dimensional hyperplane is\\u000aproved.

  15. Disorder-induced neutral solitons in degenerate ground state polymers

    Microsoft Academic Search

    Marc Thilo Figge; Maxim V. Mostovoy; Jasper Knoester

    1998-01-01

    In this letter, we study the effects of weak off-diagonal disorder on conjugated polymers with a doubly degenerate ground-state. We find that disorder induces a finite density of neutral solitons in the lattice dimerization of a polymer chain. Interchain interactions result in a linear potential between the solitons and, if sufficiently strong, bind them into pairs resulting in an exponential

  16. Disorder-induced neutral solitons in degenerate ground state polymers

    Microsoft Academic Search

    Marc Thilo Figge; Maxim V. Mostovoy; Jasper Knoester

    1999-01-01

    We study the effects of weak off-diagonal disorder on ?-conjugated polymers with a doubly degenerate ground-state. We find that disorder induces a finite density of neutral solitons in the lattice dimerization of a polymer chain. Interchain interactions result in a linear potential between the solitons and, if sufficiently strong, bind them into pairs resulting in an exponential suppression of the

  17. Broadband degenerate OPO for mid-infrared frequency comb generation

    E-print Network

    Byer, Robert L.

    Broadband degenerate OPO for mid-infrared frequency comb generation Nick Leindecker,* Alireza for generating broadband phase- and frequency-locked frequency combs in the mid-infrared. Our source is based, C. Gohle, and R. Holzwarth, "Time-domain mid-infrared frequency-comb spectrometer," Opt. Lett. 29

  18. On root systems in spaces with degenerate metric

    E-print Network

    I. V. Kostyakov; N. A. Gromov; V. V. Kuratov

    2001-02-09

    A root systems in Carroll spaces with degenerate metric are defined. It is shown that their Cartan matrices and reflection groups are affine. With the help of the geometric consideration the root system structure of affine algebras is determined by a sufficiently simple algorithm.

  19. Progranulin mutations in Dutch familial frontotemporal lobar degeneration

    Microsoft Academic Search

    Iraad F Bronner; Patrizia Rizzu; Harro Seelaar; Saskia E van Mil; Burcu Anar; Asma Azmani; Laura Donker Kaat; Sonia Rosso; Peter Heutink; John C van Swieten

    2007-01-01

    Mutations in the progranulin (PGRN) gene have recently been identified in frontotemporal lobar degeneration with ubiquitin inclusions linked to chromosome 17q21. We report here the finding of two novel frameshift mutations and three possible pathogenic missense mutations in the PGRN gene. Furthermore, we determined the frequency of PGRN mutations in familial cases recruited from a large population-based study of frontotemporal

  20. Early Detection and Treatment of Neovascular Age related Macular Degeneration

    Microsoft Academic Search

    Neil M. Bressler

    Background: The neovascular form of age-related macular degeneration (AMD) can rapidly lead to se- vere loss of central vision and adversely affect the patient's quality of life. During the 1990s the only proven treatment for neovascular AMD was laser photocoagulation. Only a minority of patients are eligi- ble to receive this treatment, however, and the treatment itself can cause acute

  1. Identifying tissue-selective transcription factor binding sites in vertebrate promoters

    E-print Network

    Identifying tissue-selective transcription factor binding sites in vertebrate promoters Andrew D the highly degenerate motifs that characterize vertebrate transcription factor binding sites. Results), but binding-site identification in vertebrates remains a difficult problem. Tissue-selective tran- scription

  2. Decreased Expression of DREAM Promotes the Degeneration of Retinal Neurons.

    PubMed

    Chintala, Shravan; Cheng, Mei; Zhang, Xiao

    2015-01-01

    The intrinsic mechanisms that promote the degeneration of retinal ganglion cells (RGCs) following the activation of N-Methyl-D-aspartic acid-type glutamate receptors (NMDARs) are unclear. In this study, we have investigated the role of downstream regulatory element antagonist modulator (DREAM) in NMDA-mediated degeneration of the retina. NMDA, phosphate-buffered saline (PBS), and MK801 were injected into the vitreous humor of C57BL/6 mice. At 12, 24, and 48 hours after injection, expression of DREAM in the retina was determined by immunohistochemistry, western blot analysis, and electrophoretic mobility-shift assay (EMSA). Apoptotic death of cells in the retina was determined by terminal deoxynucleotidyl transferace dUTP nick end labeling (TUNEL) assays. Degeneration of RGCs in cross sections and in whole mount retinas was determined by using antibodies against Tuj1 and Brn3a respectively. Degeneration of amacrine cells and bipolar cells was determined by using antibodies against calretinin and protein kinase C (PKC)-alpha respectively. DREAM was expressed constitutively in RGCs, amacrine cells, bipolar cells, as well as in the inner plexiform layer (IPL). NMDA promoted a progressive decrease in DREAM levels in all three cell types over time, and at 48 h after NMDA-treatment very low DREAM levels were evident in the IPL only. DREAM expression in retinal nuclear proteins was decreased progressively after NMDA-treatment, and correlated with its decreased binding to the c-fos-DRE oligonucleotides. A decrease in DREAM expression correlated significantly with apoptotic death of RGCs, amacrine cells and bipolar cells. Treatment of eyes with NMDA antagonist MK801, restored DREAM expression to almost normal levels in the retina, and significantly decreased NMDA-mediated apoptotic death of RGCs, amacrine cells, and bipolar cells. Results presented in this study show for the first time that down-regulation of DREAM promotes the degeneration of RGCs, amacrine cells, and bipolar cells. PMID:26020793

  3. Decreased Expression of DREAM Promotes the Degeneration of Retinal Neurons

    PubMed Central

    Chintala, Shravan; Cheng, Mei; Zhang, Xiao

    2015-01-01

    The intrinsic mechanisms that promote the degeneration of retinal ganglion cells (RGCs) following the activation of N-Methyl-D-aspartic acid-type glutamate receptors (NMDARs) are unclear. In this study, we have investigated the role of downstream regulatory element antagonist modulator (DREAM) in NMDA-mediated degeneration of the retina. NMDA, phosphate-buffered saline (PBS), and MK801 were injected into the vitreous humor of C57BL/6 mice. At 12, 24, and 48 hours after injection, expression of DREAM in the retina was determined by immunohistochemistry, western blot analysis, and electrophoretic mobility-shift assay (EMSA). Apoptotic death of cells in the retina was determined by terminal deoxynucleotidyl transferace dUTP nick end labeling (TUNEL) assays. Degeneration of RGCs in cross sections and in whole mount retinas was determined by using antibodies against Tuj1 and Brn3a respectively. Degeneration of amacrine cells and bipolar cells was determined by using antibodies against calretinin and protein kinase C (PKC)-alpha respectively. DREAM was expressed constitutively in RGCs, amacrine cells, bipolar cells, as well as in the inner plexiform layer (IPL). NMDA promoted a progressive decrease in DREAM levels in all three cell types over time, and at 48 h after NMDA-treatment very low DREAM levels were evident in the IPL only. DREAM expression in retinal nuclear proteins was decreased progressively after NMDA-treatment, and correlated with its decreased binding to the c-fos-DRE oligonucleotides. A decrease in DREAM expression correlated significantly with apoptotic death of RGCs, amacrine cells and bipolar cells. Treatment of eyes with NMDA antagonist MK801, restored DREAM expression to almost normal levels in the retina, and significantly decreased NMDA-mediated apoptotic death of RGCs, amacrine cells, and bipolar cells. Results presented in this study show for the first time that down-regulation of DREAM promotes the degeneration of RGCs, amacrine cells, and bipolar cells. PMID:26020793

  4. Adult onset thalamocerebellar degeneration in dogs associated to neuronal storage of ceroid lipopigment

    Microsoft Academic Search

    S. Sisó; C. Navarro; D. Hanzlí?ek; M. Vandevelde

    2004-01-01

    Late onset of hereditary cerebellar cortical abiotrophy has been described in a large variety of canine breeds. In some reported conditions, the cerebellar lesion is combined with degeneration of other systems. Here we describe a new hereditary cerebellar cortical degeneration in eight adult American Staffordshire and Pit Bull Terriers. The neuronal degeneration in these animals not only affects Purkinje cells

  5. Control of muscle degeneration following autotomy of a hindleg in the grasshopper, Barytettix humphreysii

    Microsoft Academic Search

    K. E. Personius; R. F. Chapman

    2002-01-01

    When the grasshopper, Barrytettix humphreysii, sheds a hindlimb during autotomy, certain thoracic muscles degenerate although they are neither directly damaged nor denervated. Muscle degeneration is induced when a leg nerve (N5) that does not innervate the thoracic muscles is severed. Together these results suggest that transneuronal mechanisms influence muscle survival. To further characterize this autotomy-induced process, we studied the degeneration

  6. Increased Nuclear NAD Biosynthesis and SIRT1 Activation Prevent Axonal Degeneration

    Microsoft Academic Search

    Toshiyuki Araki; Yo Sasaki; Jeffrey Milbrandt

    2004-01-01

    Axonal degeneration is an active program of self-destruction that is observed in many physiological and pathological settings. In Wallerian degeneration slow (wlds) mice, Wallerian degeneration in response to axonal injury is delayed because of a mutation that results in overexpression of a chimeric protein (Wlds) composed of the ubiquitin assembly protein Ufd2a and the nicotinamide adenine dinucleotide (NAD) biosynthetic enzyme

  7. Ataxia and Purkinje cell degeneration in mice lacking the CAMTA1 transcription factor

    PubMed Central

    Long, Chengzu; Grueter, Chad E.; Song, Kunhua; Qin, Song; Qi, Xiaoxia; Kong, Y. Megan; Shelton, John M.; Richardson, James A.; Zhang, Chun-Li; Bassel-Duby, Rhonda; Olson, Eric N.

    2014-01-01

    Members of the calmodulin-binding transcription activator (CAMTA) family of proteins function as calcium-sensitive regulators of gene expression in multicellular organisms ranging from plants to humans. Here, we show that global or nervous system deletion of CAMTA1 in mice causes severe ataxia with Purkinje cell degeneration and cerebellar atrophy, partially resembling the consequences of haploinsufficiency of the human CAMTA1 locus. Gene-expression analysis identified a large collection of neuronal genes that were dysregulated in the brains of CAMTA1-mutant mice, and elucidation of a consensus sequence for binding of CAMTA proteins to DNA revealed the association of CAMTA-binding sites with many of these genes. We conclude that CAMTA1 plays an essential role in the control of Purkinje cell function and survival. CAMTA1-mutant mice provide a model to study the molecular mechanisms of neurodegenerative diseases and for screening potential therapeutic interventions for such disorders. PMID:25049392

  8. A degeneration formula of Gromov-Witten invariants with respect to a curve class for degenerations from blow-ups

    E-print Network

    Chien-Hao Liu; Shing-Tung Yau

    2004-08-11

    In two very detailed, technical, and fundamental works, Jun Li constructed a theory of Gromov-Witten invariants for a singular scheme of the gluing form $Y_1\\cup_D Y_2$ that arises from a degeneration $W/{\\Bbb A}^1$ and a theory of relative Gromov-Witten invariants for a codimension-1 relative pair $(Y,D)$. As a summit, he derived a degeneration formula that relates a finite summation of the usual Gromov-Witten invariants of a general smooth fiber $W_t$ of $W/{\\Bbb A}^1$ to the Gromov-Witten invariants of the singular fiber $W_0=Y_1\\cup_D Y_2$ via gluing the relative pairs $(Y_1,D)$ and $(Y_2,D)$. The finite sum mentioned above depends on a relative ample line bundle $H$ on $W/{\\Bbb A}^1$. His theory has already applications to string theory and mathematics alike. For other new applications of Jun Li's theory, one needs a refined degeneration formula that depends on a curve class $\\beta$ in $A_{\\ast}(W_t)$ or $H_2(W_t;{\\Bbb Z})$, rather than on the line bundle $H$. Some monodromy effect has to be taken care of to deal with this. For the simple but useful case of a degeneration $W/{\\Bbb A}^1$ that arises from blowing up a trivial family $X\\times{\\Bbb A}^1$, we explain how the details of Jun Li's work can be employed to reach such a desired degeneration formula. The related set $\\Omega_{(g,k;\\beta)}$ of admissible triples adapted to $(g,k;\\beta)$ that appears in the formula can be obtained via an analysis on the intersection numbers of relevant cycles and a study of Mori cones that appear in the problem. This set is intrinsically determined by $(g,k;\\beta)$ and the normal bundle ${\\cal N}_{Z/X}$ of the smooth subscheme $Z$ in $X$ to be blown up.

  9. Degeneration and gluing of Kuranishi structures in Gromov-Witten theory and the degeneration/gluing axioms for open Gromov-Witten invariants under a symplectic cut

    E-print Network

    Chien-Hao Liu; Shing-Tung Yau

    2006-09-18

    We study the degeneration and the gluing of Kuranishi structures in Gromov-Witten theory under a symplectic cut. This leads us to a degeneration axiom and a gluing axiom for open Gromov-Witten invariants. They provide then a route to the construction of virtual fundamental chains via specialization. Comments on the equivalence of the degeneration formula of closed Gromov-Witten invariants by Li-Ruan/Li versus Ionel-Parker are given in the Appendix.

  10. Juvenile-Onset Macular Degeneration and Allied Disorders

    PubMed Central

    North, Victoria; Gelman, Rony; Tsang, Stephen H.

    2015-01-01

    While age-related macular degeneration (AMD) is a leading cause of central vision loss among the elderly, many inherited diseases that present earlier in life share features of AMD. These diseases of juvenile-onset macular degeneration include Stargardt disease, Best disease, retinitis pigmentosa, X-linked retinoschisis, and other allied disorders. In particular, they can be accompanied by the appearance of drusen, geographic atrophy, macular hyperpigmentation, choroidal neovascularization, and disciform scarring just as in AMD, and often may be confused for the adult form of the disease. Diagnosis based on funduscopic findings alone can be challenging. However, the use of diagnostic studies such as electroretinography, electrooculography, optical coherence tomography, and fundus autofluorescence in conjunction with genetic testing can lead to an accurate diagnosis. PMID:24732760

  11. Radiative generation of neutrino mixing: Degenerate masses and threshold corrections

    NASA Astrophysics Data System (ADS)

    Hollik, Wolfgang Gregor

    2015-02-01

    Degenerate neutrino masses are excluded by experiment. The experimentally measured mass squared differences together with the yet undetermined absolute neutrino mass scale allow for a quasidegenerate mass spectrum. For the lightest neutrino mass larger than roughly 0.1 eV, we analyze the influence of threshold corrections at the electroweak scale. We show that typical one-loop corrections can generate the observed neutrino mixing as well as the mass differences starting from exactly degenerate masses at the tree level. Those threshold corrections have to be explicitly flavor violating. Flavor-diagonal, nonuniversal corrections are not sufficient to simultaneously generate the correct mixing and the mass differences. We apply the new insights to an extension of the Minimal Supersymmetric Standard Model with nonminimal flavor violation in the soft breaking terms and discuss the low-energy threshold corrections to the light neutrino mass matrix in that model.

  12. Universal dynamics of a degenerate unitary Bose gas

    NASA Astrophysics Data System (ADS)

    Cornell, Eric

    2014-03-01

    It has long been thought that one can not study a degenerate Bose gas with fully resonant (unitary) interactions because the gas is unstable to three-body recombination. We find empirically instead that after a Bose-Einstein condensate has been tuned from a weakly interacting state to a fully unitary gas at the peak of a Feshbach resonance, it survives for a time long enough to permit the characterization momentum-population dynamics. In particular, a high momentum tail forms and comes to a quasi-steady state in perhaps 100 microseconds, while the sample continues to survive and indeed remains degenerate for considerably longer. We show that the shape- and time-dependence of the momentum distribution scale in a universal way with sample density. This work was done in collaboration with Phil Makotyn, Deborah Jin, Cathy Klauss and David Goldberger. This work was supported by NSF, ONR and NIST.

  13. Histology of spheroidal degeneration of the cornea in Labrador.

    PubMed Central

    Johnson, G. J.; Overall, M.

    1978-01-01

    Nine specimens of the corneas of patients from Labrador and Northern Newfoundland affected by spheroidal degeneration (climatic droplet keratopathy) have been examined microscopically. Histochemical stains confirmed studies of similar corneal degenerations from other geographical areas that the droplets contain a protein which does not have all the characteristic properties of elastic tissue. Staining compatible in some instances with fibrin and "fibrinoid" was found. By immunoperoxidase techniques the droplets were located in the zones of greatest concentration of various plasma constituents, especially albumin and immunoglobulins G and A. Reasons are given why the abnormal deposits are not thought to be derived directly from corneal collagen. It is suggested that some of the plasma proteins, which are known to be diffusing through the cornea from the limbal vessels under normal conditions are acted upon by the ultraviolet light reflected from the ice of Labrador and degraded so that they accumulate in the superficial stroma. Images PMID:629911

  14. Experimental analysis of degenerate vector phase-sensitive amplification.

    PubMed

    Lorences-Riesgo, Abel; Chiarello, Fabrizio; Lundström, Carl; Karlsson, Magnus; Andrekson, Peter A

    2014-09-01

    We comprehensively investigate a degenerate vector phase-sensitive amplifier (PSA). We determine the gain dependence on the relative phase and polarization angle between the pumps and the degenerate signal wave. The vector PSA is experimentally shown to be sensitive to the pump states of polarization (SOP) due to polarization mode dispersion in the fiber. However, the scheme performance agrees well with theory under specific pump SOPs and we achieve an on-off gain over 10 dB with a small deviation from the theoretically expected results. In comparison to the scalar scheme, the proposed vector scheme has larger tolerance for pump depletion due to four-wave mixing between pumps and generation of higher-order idlers. PMID:25321564

  15. Chlorogenic acid and coffee prevent hypoxia-induced retinal degeneration.

    PubMed

    Jang, Holim; Ahn, Hong Ryul; Jo, Hyoung; Kim, Kyung-A; Lee, Eun Ha; Lee, Ki Won; Jung, Sang Hoon; Lee, Chang Y

    2014-01-01

    This study explored whether chlorogenic acid (CGA) and coffee have protective effects against retinal degeneration. Under hypoxic conditions, the viability of transformed retinal ganglion (RGC-5) cells was significantly reduced by treatment with the nitric oxide (NO) donor S-nitroso-N-acetylpenicillamine (SNAP). However, pretreatment with CGA attenuated cell death in a concentration-dependent manner. In addition, CGA prevented the up-regulation of apoptotic proteins such as Bad and cleaved caspase-3. Similar beneficial effects of both CGA and coffee extracts were observed in mice that had undergone an optic nerve crush (ONC) procedure. CGA and coffee extract reduced cell death by preventing the down-regulation of Thy-1. Our in vitro and in vivo studies demonstrated that coffee and its major component, CGA, significantly reduce apoptosis of retinal cells induced by hypoxia and NO, and that coffee consumption may help in preventing retinal degeneration. PMID:24295042

  16. Degenerate band edge resonances in periodic silicon ridge waveguides.

    PubMed

    Wood, Michael G; Burr, Justin R; Reano, Ronald M

    2015-06-01

    We experimentally demonstrate degenerate band edge resonances in periodic Si ridge waveguides that are compatible with carrier injection modulation for active electro-optical devices. The resonant cavities are designed using a combination of the plane-wave expansion method and the finite difference time domain technique. Measured and simulated quality factors of the first band edge resonances scale to the fifth power of the number of periods. Quality factor scaling is determined to be limited by fabrication imperfections. Compared to resonators based on a regular transmission band edge, degenerate band edge devices can achieve significantly larger quality factors in the same number of periods. Applications include compact electro-optical switches, modulators, and sensors that benefit from high-quality factors and large distributed electric fields. PMID:26030540

  17. Current-Drive Efficiency in a Degenerate Plasma

    SciTech Connect

    S. Son and N.J. Fisch

    2005-11-01

    a degenerate plasma, the rates of electron processes are much smaller than the classical model would predict, affecting the efficiencies of current generation by external non-inductive means, such as by electromagnetic radiation or intense ion beams. For electron-based mechanisms, the current-drive efficiency is higher than the classical prediction by more than a factor of 6 in a degenerate hydrogen plasma, mainly because the electron-electron collisions do not quickly slow down fast electrons. Moreover, electrons much faster than thermal speeds are more readily excited without exciting thermal electrons. In ion-based mechanisms of current drive, the efficiency is likewise enhanced due to the degeneracy effects, since the electron stopping power on slow ion beams is significantly reduced.

  18. Hypertrophic olivary degeneration after resection of a cerebellar tumor.

    PubMed

    Akar, Serra; Drappatz, Jan; Hsu, Liangge; Blinder, Russell A; Black, Peter McL; Kesari, Santosh

    2008-05-01

    We report a case of hypertrophic olivary degeneration due to cerebellar surgery for a low-grade tumor. A 27-year-old female presented with right-sided paresthesias and intermittent leg paresis following a right cerebellar resection of a tumor 2 weeks prior. One month later, her symptoms remained stable while her neurological examination demonstrated slight right hemi-body hypoesthesia and subtle appendicular ataxia in her right upper extremity. An MRI scan revealed a hypertrophied left anterolateral medulla with increased T2 signal and no diffusion abnormality. The T2 hyperintensity and hypertrophy slowly resolved and she clinically improved without further intervention. Hypertrophic olivary degeneration may be mistaken for tumor progression, post-operative vasculopathy or granulation tissue and should be considered in patients undergoing cerebellar surgery. PMID:18217209

  19. Pegaptanib for Neovascular Age-Related Macular Degeneration

    Microsoft Academic Search

    Evangelos S. Gragoudas; Anthony P. Adamis; Emmett T. Cunningham; Matthew Feinsod; David R. Guyer

    2010-01-01

    background Pegaptanib, an anti-vascular endothelial growth factor therapy, was evaluated in the treatment of neovascular age-related macular degeneration. methods We conducted two concurrent, prospective, randomized, double-blind, multicenter, dose-ranging, controlled clinical trials using broad entry criteria. Intravitreous injec- tion into one eye per patient of pegaptanib (at a dose of 0.3 mg, 1.0 mg, or 3.0 mg) or sham injections were

  20. Simulating 4D Simplicial Gravity including Degenerate Triangulations

    E-print Network

    S. Bilke; G. Thorleifsson

    1998-09-15

    We extend simulations of simplicial gravity in four dimensions to include {\\it degenerate} triangulations and demonstrate that using this ensemble the geometric finite-size effects are much reduced. We provide strong numerical evidence for the existence of an exponential bound on the entropy of the model and establish that the phase structure is identical to that of a corresponding model restricted to an ensemble of combinatorial triangulations.

  1. Immunopathological aspects of age-related macular degeneration

    Microsoft Academic Search

    Mrinali Patel; Chi-Chao Chan

    2008-01-01

    Age-related macular degeneration (AMD) represents a leading cause of blindness worldwide. While the clinical and histopathological\\u000a aspects of AMD are well characterized, its etiology and pathogenesis remain unclear. Recent findings suggest a role for immunologic\\u000a processes in AMD pathogenesis, including the age-related generation of extracellular deposits inside the Brusch membrane and\\u000a beneath the retinal pigment epithelium, recruitment of macrophages for

  2. On modular transformations of non-degenerate toric conformal blocks

    E-print Network

    Nemkov, Nikita

    2015-01-01

    We derive and solve the difference equations on the toric modular kernel following from the consistency relations in the fusion algebra. The result is explicit and simple series expansion for the toric modular kernel of non-degenerate Virasoro conformal blocks. We show that this expansion is equivalent to the celebrated integral representation due to B. Ponsot and J. Teschner. We also interpret obtained series representation as a non-perturbative expansion and note that this raises further questions.

  3. On modular transformations of non-degenerate toric conformal blocks

    E-print Network

    Nikita Nemkov

    2015-04-27

    We derive and solve the difference equations on the toric modular kernel following from the consistency relations in the fusion algebra. The result is explicit and simple series expansion for the toric modular kernel of non-degenerate Virasoro conformal blocks. We show that this expansion is equivalent to the celebrated integral representation due to B. Ponsot and J. Teschner. We also interpret obtained series representation as a non-perturbative expansion and note that this raises further questions.

  4. The Future of Neovascular Age-Related Macular Degeneration

    Microsoft Academic Search

    Chirag P. Shah; Jeffrey S. Heier

    \\u000a The treatment of neovascular age-related macular degeneration (AMD) will continue to evolve dramatically. Researchers are\\u000a working to find new therapeutics targeting important pathways involved in angiogenesis, including: Vascular endothelial growth\\u000a factor (VEGF) inhibition Vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor inhibition\\u000a (PDGFR), including tyrosine kinase inhibitors, RNA interference, and vaccine therapy Radiation therapy utilizing novel local

  5. Uniformly Levi degenerate CR manifolds: The 5-dimensional case

    Microsoft Academic Search

    Peter Ebenfelt

    2001-01-01

    In this paper, we consider real hypersurfaces $M$ in $\\\\Bbb C^3$ (or more\\u000agenerally, 5-dimensional CR manifolds of hypersurface type) at uniformly Levi\\u000adegenerate points, i.e. Levi degenerate points such that the rank of the Levi\\u000aform is constant in a neighborhood. We also require the hypersurface to satisfy\\u000aa certain second order nondegeneracy condition (called 2-nondegeneracy) at the\\u000apoint.

  6. Smoking and Age-Related Macular Degeneration: Review and Update

    PubMed Central

    Velilla, Sara; García-Medina, José Javier; García-Layana, Alfredo; Pons-Vázquez, Sheila; Pinazo-Durán, M. Dolores; Gómez-Ulla, Francisco; Arévalo, J. Fernando; Díaz-Llopis, Manuel; Gallego-Pinazo, Roberto

    2013-01-01

    Age-related macular degeneration (AMD) is one of the main socioeconomical health issues worldwide. AMD has a multifactorial etiology with a variety of risk factors. Smoking is the most important modifiable risk factor for AMD development and progression. The present review summarizes the epidemiological studies evaluating the association between smoking and AMD, the mechanisms through which smoking induces damage to the chorioretinal tissues, and the relevance of advising patients to quit smoking for their visual health. PMID:24368940

  7. Therapy of Nonexudative Age-Related Macular Degeneration

    Microsoft Academic Search

    Annal D. Meleth; Veena R. Raiji; Nupura Krishnadev; Emily Y. Chew

    \\u000a Age related macular degeneration (AMD) is the leading cause of blindness among adults over the age of 65 in the Western world.\\u000a The prevalence of AMD is expected to increase dramatically, from 1.75 million in 2000 to 2.95 million in 2020, due to the\\u000a rapidly aging population. Given the large and now increasing burden of disease, the identification of modifiable

  8. Evidence for the degenerate dwarf nature of Cygnus X-2

    Microsoft Academic Search

    G. Branduardi; N. D. Kylafis; D. Q. Lamb; K. O. Mason

    1980-01-01

    Observations of Cygnus X-2 using the Copernicus sattelite have revealed a novel relationship between the spectral hardness and the intensity of this souce in the 3--8 keV band. This behavior is very similar to that predicted for a spherically accreting nonmagnetic degenerate dwarf. The data, interpreted in terms of this model, yield a mass 0.35 +- 0.05 M\\/sub sun\\/, a

  9. Helicoidal peripapillary chorioretinal degeneration: electrophysiology and psychophysics in 17 patients

    Microsoft Academic Search

    Thor Eysteinsson; Fridbert Jónasson; Vésteinn Jónsson; Alan C Bird

    1998-01-01

    AIMSTo characterise retinal function using electrophysiological and psychophysical tests in 17 patients with helicoidal peripapillary chorioretinal degeneration.METHODSThe electroretinogram (ERG) was recorded using gold foil corneal electrodes. The electro-oculogram (EOG) was recorded using a standard protocol. Dark adaptometry was recorded with an SST-1 dark adaptometer and colour vision assessed with Ishihara plates and Farnsworth D-15.RESULTSAll subjects had a recordable ERG. The

  10. Suppression of Density Fluctuations in a Quantum Degenerate Fermi Gas

    SciTech Connect

    Sanner, Christian; Su, Edward J.; Keshet, Aviv; Gommers, Ralf; Shin, Yong-il; Huang Wujie; Ketterle, Wolfgang [MIT-Harvard Center for Ultracold Atoms, Research Laboratory of Electronics, and Department of Physics, Massachusetts Institute of Technology, Cambridge Massachusetts 02139 (United States)

    2010-07-23

    We study density profiles of an ideal Fermi gas and observe Pauli suppression of density fluctuations (atom shot noise) for cold clouds deep in the quantum degenerate regime. Strong suppression is observed for probe volumes containing more than 10 000 atoms. Measuring the level of suppression provides sensitive thermometry at low temperatures. After this method of sensitive noise measurements has been validated with an ideal Fermi gas, it can now be applied to characterize phase transitions in strongly correlated many-body systems.

  11. Resistance to axonal degeneration after nerve compression in experimental diabetes.

    PubMed Central

    Dyck, P J; Engelstad, J K; Giannini, C; Lais, A C; Minnerath, S R; Karnes, J L

    1989-01-01

    To determine the effect of diabetes on the development of axonal degeneration after acute nerve compression, the mobilized peroneal nerves of rats with streptozotocin-induced diabetes and of control rats were compressed at 150 mmHg (1 mmHg = 133 Pa) for 30 min by using specially devised cuffs. At three intervals after compression--3 days, rats diabetic for 31 wk; 14 days, diabetic for 6 wk; and 24 days, diabetic for 31 wk--groups of nerves were studied to assess numbers and sizes of fibers above, at, and below the cuff and to assess frequency of fiber degeneration in teased fibers from nerve distal to the cuff. Teased fibers with pathologic abnormalities were more frequent in nerves from controls than in nerves from diabetic rats in all three groups but the difference was statistically significant only at 3 and 14 days after compression. The lack of significant difference at 24 days may be explained by higher rates of disappearance of degenerating products and of fiber regeneration at 24 than at 3 and 14 days. This study provides evidence that in addition to delaying the reported functional deficit of vibratory detection threshold and conduction block during nerve compression, diabetes also may partially prevent axonal injury. Low nerve myo-inositol concentration did not predispose diabetic nerve to acute compression injury. If these results also apply to human diabetes and if repeated acute compression is involved in the genesis of fiber degeneration in entrapment, then a higher frequency of entrapment neuropathy among diabetics might be due to mechanisms other than increased susceptibility of fibers to acute compression--e.g., possibly to greater constriction of nerve due to pathologic alterations of the carpal ligament. Images PMID:2928319

  12. Measurement of smoke concentration using degenerate four-wave mixing

    Microsoft Academic Search

    T C Cole; W A Cole; R W Pitz

    2002-01-01

    Degenerate four-wave mixing (DFWM) was successfully used to monitor a wide range of smoke concentrations (0.1-10 mg m?3) in sample cells. To the authors' knowledge, this is the first measurement of smoke by DFWM. The DFWM method is very sensitive, measuring down to ?0.1 ppb soot volume fraction. To verify the visible laser DFWM system, NO2 concentrations from 2 to

  13. Humor and laughter in patients with cerebellar degeneration.

    PubMed

    Frank, B; Propson, B; Göricke, S; Jacobi, H; Wild, B; Timmann, D

    2012-06-01

    Humor is a complex behavior which includes cognitive, affective and motor responses. Based on observations of affective changes in patients with cerebellar lesions, the cerebellum may support cerebral and brainstem areas involved in understanding and appreciation of humorous stimuli and expression of laughter. The aim of the present study was to examine if humor appreciation, perception of humorous stimuli, and the succeeding facial reaction differ between patients with cerebellar degeneration and healthy controls. Twenty-three adults with pure cerebellar degeneration were compared with 23 age-, gender-, and education-matched healthy control subjects. No significant difference in humor appreciation and perception of humorous stimuli could be found between groups using the 3 Witz-Dimensionen Test, a validated test asking for funniness and aversiveness of jokes and cartoons. Furthermore, while observing jokes, humorous cartoons, and video sketches, facial expressions of subjects were videotaped and afterwards analysed using the Facial Action Coding System. Using depression as a covariate, the number, and to a lesser degree, the duration of facial expressions during laughter were reduced in cerebellar patients compared to healthy controls. In sum, appreciation of humor appears to be largely preserved in patients with chronic cerebellar degeneration. Cerebellar circuits may contribute to the expression of laughter. Findings add to the literature that non-motor disorders in patients with chronic cerebellar disease are generally mild, but do not exclude that more marked disorders may show up in acute cerebellar disease and/or in more specific tests of humor appreciation. PMID:22012411

  14. Exact nonlinear excitations in double-degenerate plasmas

    NASA Astrophysics Data System (ADS)

    Akbari-Moghanjoughi, M.

    2012-06-01

    In this work, we use the conventional hydrodynamics formalism and incorporate the Chew-Goldberger-Low double-adiabatic theory to evaluate the nonlinear electrostatic ion excitations in double-degenerate (electron spin-orbit degenerate) magnetized quantum plasmas. Based on the Sagdeev pseudopotential method, an exact general pseudopotential is calculated which leads to the allowed Mach-number range criteria for such localized density structures in an anisotropic magnetized plasma. We employ the criteria on the Mach-number range for diverse magnetized quantum plasma with different equations of state. It is remarked that various plasma fractional parameters such as the system dimensionality, ion-temperature, relativistic-degeneracy, Zeeman-energy, and plasma composition are involved in the stability of an obliquely propagating nonlinear ion-acoustic wave in a double-degenerate quantum plasma. Current study is most appropriate for nonlinear wave analysis in dense astrophysical magnetized plasma environments such as white-dwarfs and neutron-star crusts where the strong magnetic fields can be present.

  15. CODEHOP (COnsensus-DEgenerate Hybrid Oligonucleotide Primer) PCR primer design.

    PubMed

    Rose, Timothy M; Henikoff, Jorja G; Henikoff, Steven

    2003-07-01

    We have developed a new primer design strategy for PCR amplification of distantly related gene sequences based on consensus-degenerate hybrid oligonucleotide primers (CODEHOPs). An interactive program has been written to design CODEHOP PCR primers from conserved blocks of amino acids within multiply-aligned protein sequences. Each CODEHOP consists of a pool of related primers containing all possible nucleotide sequences encoding 3-4 highly conserved amino acids within a 3' degenerate core. A longer 5' non-degenerate clamp region contains the most probable nucleotide predicted for each flanking codon. CODEHOPs are used in PCR amplification to isolate distantly related sequences encoding the conserved amino acid sequence. The primer design software and the CODEHOP PCR strategy have been utilized for the identification and characterization of new gene orthologs and paralogs in different plant, animal and bacterial species. In addition, this approach has been successful in identifying new pathogen species. The CODEHOP designer (http://blocks.fhcrc.org/codehop.html) is linked to BlockMaker and the Multiple Alignment Processor within the Blocks Database World Wide Web (http://blocks.fhcrc.org). PMID:12824413

  16. Plant Y chromosome degeneration is retarded by haploid purifying selection.

    PubMed

    Chibalina, Margarita V; Filatov, Dmitry A

    2011-09-13

    Sex chromosomes evolved many times independently in many different organisms [1]. According to the currently accepted model, X and Y chromosomes evolve from a pair of autosomes via a series of inversions leading to stepwise expansion of a nonrecombining region on the Y chromosome (NRY) and the consequential degeneration of genes trapped in the NRY [2]. Our results suggest that plants represent an exception to this rule as a result of their unique life-cycle that includes alteration of diploid and haploid generations and widespread haploid expression of genes in plant gametophytes [3]. Using a new high-throughput approach, we identified over 400 new genes expressed from X and Y chromosomes in Silene latifolia, a plant that evolved sex chromosomes about 10 million years ago. Y-linked genes show faster accumulation of amino-acid replacements and loss of expression, compared to X-linked genes. These degenerative processes are significantly less pronounced in more constrained genes and genes that are likely exposed to haploid-phase selection. This may explain why plants retain hundreds of expressed Y-linked genes despite millions of years of Y chromosome degeneration, whereas animal Y chromosomes are almost completely degenerate. PMID:21889890

  17. Production of quantum degenerate strontium gases: Larger, better, faster, colder

    E-print Network

    Stellmer, Simon; Schreck, Florian

    2012-01-01

    We report on an improved scheme to generate Bose-Einstein condensates (BECs) and degenerate Fermi gases of strontium. This scheme allows us to create quantum gases with higher atom number, a shorter time of the experimental cycle, or deeper quantum degeneracy than before. We create a BEC of 84-Sr exceeding 10^7 atoms, which is a 30-fold improvement over previously reported experiments. We increase the atom number of 86-Sr BECs to 2.5x10^4 (a fivefold improvement), and refine the generation of attractively interacting 88-Sr BECs. We present a scheme to generate 84-Sr BECs with a cycle time of 2s, which, to the best of our knowledge, is the shortest cycle time of BEC experiments ever reported. We create deeply-degenerate 87-Sr Fermi gases with T/T_F as low as 0.10(1), where the number of populated nuclear spin states can be set to any value between one and ten. Furthermore, we report on a total of five different double-degenerate Bose-Bose and Bose-Fermi mixtures. These studies prepare an excellent starting poi...

  18. Exact nonlinear excitations in double-degenerate plasmas

    SciTech Connect

    Akbari-Moghanjoughi, M. [Department of Physics, Faculty of Sciences, Azarbaijan University of Tarbiat Moallem, 51745-406 Tabriz (Iran, Islamic Republic of)

    2012-06-15

    In this work, we use the conventional hydrodynamics formalism and incorporate the Chew-Goldberger-Low double-adiabatic theory to evaluate the nonlinear electrostatic ion excitations in double-degenerate (electron spin-orbit degenerate) magnetized quantum plasmas. Based on the Sagdeev pseudopotential method, an exact general pseudopotential is calculated which leads to the allowed Mach-number range criteria for such localized density structures in an anisotropic magnetized plasma. We employ the criteria on the Mach-number range for diverse magnetized quantum plasma with different equations of state. It is remarked that various plasma fractional parameters such as the system dimensionality, ion-temperature, relativistic-degeneracy, Zeeman-energy, and plasma composition are involved in the stability of an obliquely propagating nonlinear ion-acoustic wave in a double-degenerate quantum plasma. Current study is most appropriate for nonlinear wave analysis in dense astrophysical magnetized plasma environments such as white-dwarfs and neutron-star crusts where the strong magnetic fields can be present.

  19. Surface Waves in Anisotropic Elastic Materials for Which the Matrix N(v) is Extraordinary Degenerate, Degenerate, or Semisimple

    Microsoft Academic Search

    T. C. T. Ting

    1997-01-01

    The 6 × 6 real matrix N(v) for anisotropic elastic materials under a two-dimensional steady-state motion with speed v is extraordinary degenerate when N(v) has three identical complex eigenvalues p but has only one associated eigenvector. It has been an open question if such an N(v) exists for surface waves. In this paper we first modify the solution for ordinary

  20. Control of muscle degeneration following autotomy of a hindleg in the grasshopper, Barytettix humphreysii.

    PubMed

    Personius, K E.; Chapman, R F.

    2002-01-01

    When the grasshopper, Barrytettix humphreysii, sheds a hindlimb during autotomy, certain thoracic muscles degenerate although they are neither directly damaged nor denervated. Muscle degeneration is induced when a leg nerve (N5) that does not innervate the thoracic muscles is severed. Together these results suggest that transneuronal mechanisms influence muscle survival. To further characterize this autotomy-induced process, we studied the degeneration of a thoracic tergotrochanteral muscle (M#133b,c) following autotomy or experimental manipulation in adult animals. Its degeneration is correlated with reduced activity of its neural input and occurs by programmed cell death (PCD). PCD onset is variable between individual muscle fibers, indicating that the trigger of degeneration is fiber specific. Muscle degeneration appears to be triggered by the loss of proprioceptive input from the autotomized limb, since severing of axons from proprioceptive organs, but not exteroceptive chemo- or mechanoreceptors, leads to muscle degeneration. Muscle disuse, neuronal degeneration, or changes in juvenile hormone titer do not appear to play a role in autotomy-induced degeneration. We propose that the loss of proprioceptive input from proximal campaniform sensilla on the tibia deafferents the thoracic muscle motor neurons and leads to a decrease in their activity. Muscle degeneration is ultimately triggered by the loss of normal neural activity. PMID:12770136

  1. Inhibition of Polyisoprenylated Methylated Protein Methyl Esterase by Synthetic Musks Induces Cell Degeneration

    PubMed Central

    Ayuk-Takem, Lambert; Amissah, Felix; Aguilar, Byron J.; Lamango, Nazarius S.

    2013-01-01

    Synthetic fragrances are persistent environmental pollutants that tend to bioaccumulate in animal tissues. They are widely used in personal care products and cleaning agents. Worldwide production of Galaxolide and Tonalide are in excess of 4500 tons annually. Because of their widespread production and use, they have been detected in surface waters and fish in the US and Europe. Consumption of contaminated water and fish from such sources leads to bioaccumulation and eventual toxicity. Since fragrances and flavors bear structural similarities to polyisoprenes, it was of interest to determine whether toxicity by Galaxolide and Tonalide may be linked with polyisoprenylated methylated protein methyl esterase (PMPMEase) inhibition. A concentration-dependent study of PMPMEase inhibition by Galaxolide and Tonalide as well as their effects on the degeneration of cultured cells were conducted. Galaxolide and Tonalide inhibited purified porcine liver PMPMEase with Ki values of 11 and 14 µM, respectively. Galaxolide and Tonalide also induced human cancer cell degeneration with EC50 values of 26 and 98 µM (neuroblastoma SH-SY5Y cells) and 58 and 14 µM (lung cancer A549 cells), respectively. The effects on cell viability correlate well with the inhibition of PMPMEase activity in the cultured cells. Molecular docking analysis revealed that the binding interactions are most likely between the fragrance molecules and hydrophobic amino acids in the active site of the enzyme. These results appear to suggest that the reported neurotoxicity of these compounds may be associated with their inhibition of PMPMEase. Exposure to fragrances may pose a significant risk to individuals predisposed to developing degenerative disorders. PMID:22489002

  2. Structural Basis for Degenerate Recognition of Natural HIV Peptide Variants by Cytotoxic Lymphocytes

    SciTech Connect

    Martinez-Hackert,E.; Anikeeva, N.; Kalams, S.; Walker, B.; Hendrickson, W.; Sykulev, Y.

    2006-01-01

    It is well established that even small changes in amino acid side chains of antigenic peptide bound to MHC protein may completely abrogate recognition of the peptide-MHC (pMHC) complex by the T-cell receptor (TCR). Often, however, several non-conservative substitutions in the peptide antigen are accommodated and do not impair its recognition by TCR. For example, a preponderance of natural sequence variants of the HIV p17 Gag-derived peptide SLYNTVATL (SL9) are recognized by cytotoxic T lymphocytes (CTL), which implies that interactions with SL9 variants are degenerate both with respect to the class I MHC molecule and with respect to TCR. Here we study the molecular basis for this degenerate recognition of SL9 variants. We show that several SL9 variants bind comparably well to soluble HLA-A2 and to a particular soluble TCR and that these variants are active in the cognate cytotoxicity assay. Natural SL9 variation is restricted by its context in the HIV p17 matrix protein, and we have used synthetic variants to explore the wider spectrum of recognition. High-resolution crystal structures of seven selected SL9 variants bound to HLA-A2 all have remarkably similar peptide conformations and side-chain dispositions outside sites of substitution. This preservation of the peptide conformation despite epitope variations suggests a mechanism for the observed degeneracy in pMHC recognition by TCR, and may contribute to the persistence of SL9-mediated immune responses in chronically infected individuals.

  3. Subconjunctival Palomid 529 in the treatment of neovascular age-related macular degeneration

    PubMed Central

    Dalal, Monica; Jacobs-El, Naima; Nicholson, Benjamin; Tuo, Jingsheng; Chew, Emily; Chan, Chi-Chao; Nussenblatt, Robert; Ferris, Frederick

    2014-01-01

    Background Recent evidence suggests that neovascular age-related macular degeneration (AMD) may have an immune mediated component. Palomid 529, an investigational medication involving the immune Akt/mTOR pathway, is unique in dissociating both targets of rapamycin complexes TORC1 and TORC2. This small short-term pilot study assesses the safety of subconjunctival Palomid 529 in the treatment of neovascular AMD, with some limited efficacy information. Methods In this 12-week phase I open-label prospective pilot study, five participants with neovascular age-related macular degeneration that were refractory to intravitreal anti-vascular endothelial growth factor (VEGF) received three serial monthly subconjunctival doses of 1.9 mg Palomid 529. All participants were also offered concomitant monthly intravitreal anti-VEGF injections. Safety was monitored via adverse events recording. Additional outcome measures included visual acuity, optical coherence tomography, fluorescein angiography, indocyanine green angiography and fundus photography. Results The study drug was well-tolerated by all participants. There were no drug-related adverse events and no serious adverse events. A depot formed at the injection site, which persisted at the end of the study. In these anti-VEGF refractory patients, no clinically important changes in best-corrected visual acuity, fluorescein leakage pattern, choroidal neovascularization size on indocyanine green angiography, or autofluorescence pattern on fundus autofluorescence were observed compared to baseline. The fluid status, assessed with optical coherence tomography showed that central retinal thickness and macular volume remained stable in three participants, while the other two participants clinically progressed. Conclusions Serial subconjunctival injections of Palomid 529 were well-tolerated and resulted in depot formation. There were no concerns for any ocular or systemic toxicity during this small short-term study. Larger randomized studies are required to determine efficacy. PMID:23689994

  4. A structural and functional analysis of Nna1 in Purkinje cell degeneration (pcd) mice

    PubMed Central

    Wu, Hui-Yuan; Wang, Taiyu; Li, Leyi; Correia, Kristen; Morgan, James I.

    2012-01-01

    The axotomy-inducible enzyme Nna1 defines a subfamily of M14 metallocarboxypeptidases, and its mutation underlies the Purkinje cell degeneration (pcd) mouse. However, the relationship among its catalytic activity, substrate specificities, and the critical processes of neurodegeneration/axon regeneration is incompletely understood. Here we used a transgenic rescue strategy targeting expression of modified forms of Nna1 to Purkinje cells in pcd mice to determine structure-activity relationships for neuronal survival and in parallel characterized the enzymatic properties of purified recombinant Nna1. The Nna1 subfamily uniquely shares conserved substrate-determining residues with aspartoacylase that, when mutated, cause Canavan disease. Homologous mutations (D1007E and R1078E) inactivate Nna1 in vivo, as does mutation of its catalytic glutamate (E1094A), which implies that metabolism of acidic substrates is essential for neuronal survival. Consistent with reports that Nna1 is a tubulin glutamylase, recombinant Nna1—but not the catalytic mutants—removes glutamate from tubulin. Recombinant Nna1 metabolizes synthetic substrates with 2 or more C-terminal glutamate (but not aspartate) residues (Vmax for 3 glutamates is ?7-fold higher than 2 glutamates although KM is similar). Catalysis is not ATP/GTP dependent, and mutating the ATP/GTP binding site of Nna1 has no effect in vivo. Nna1 is a monomeric enzyme essential for neuronal survival through hydrolysis of polyglutamate-containing substrates.—Wu, H.-Y., Wang, T., Li, L., Correia, K., Morgan, J. I. A structural and functional analysis of Nna1 in Purkinje cell degeneration (pcd) mice. PMID:22835831

  5. Application of Degenerately Doped Metal Oxides in the Study of Photoinduced Interfacial Electron Transfer.

    PubMed

    Farnum, Byron H; Morseth, Zachary A; Brennaman, M Kyle; Papanikolas, John M; Meyer, Thomas J

    2015-06-18

    Degenerately doped In2O3:Sn semiconductor nanoparticles (nanoITO) have been used to study the photoinduced interfacial electron-transfer reactivity of surface-bound [Ru(II)(bpy)2(4,4'-(PO3H2)2-bpy)](2+) (RuP(2+)) molecules as a function of driving force over a range of 1.8 eV. The metallic properties of the ITO nanoparticles, present within an interconnected mesoporous film, allowed for the driving force to be tuned by controlling their Fermi level with an external bias while their optical transparency allowed for transient absorption spectroscopy to be used to monitor electron-transfer kinetics. Photoinduced electron transfer from excited-state -RuP(2+*) molecules to nanoITO was found to be dependent on applied bias and competitive with nonradiative energy transfer to nanoITO. Back electron transfer from nanoITO to oxidized -RuP(3+) was also dependent on the applied bias but without complication from inter- or intraparticle electron diffusion in the oxide nanoparticles. Analysis of the electron injection kinetics as a function of driving force using Marcus-Gerischer theory resulted in an experimental estimate of the reorganization energy for the excited-state -RuP(3+/2+*) redox couple of ?* = 0.83 eV and an electronic coupling matrix element, arising from electronic wave function overlap between the donor orbital in the molecule and the acceptor orbital(s) in the nanoITO electrode, of Hab = 20-45 cm(-1). Similar analysis of the back electron-transfer kinetics yielded ? = 0.56 eV for the ground-state -RuP(3+/2+) redox couple and Hab = 2-4 cm(-1). The use of these wide band gap, degenerately doped materials provides a unique experimental approach for investigating single-site electron transfer at the surface of oxide nanoparticles. PMID:25668488

  6. Expression of bioactive bone morphogenetic proteins in the subacromial bursa of patients with chronic degeneration of the rotator cuff

    PubMed Central

    Neuwirth, Jana; Fuhrmann, Renée AE; Veit, Amanda; Aurich, Matthias; Stonâns, Ilmars; Trommer, Tilo; Hortschansky, Peter; Chubinskaya, Susanna; Mollenhauer, Juergen A

    2006-01-01

    Degeneration of the rotator cuff is often associated with inflammation of the subacromial bursa and focal mineralization of the supraspinatus tendon. Portions of the supraspinatus tendon distant from the insertion site could transform into fibrous cartilage, causing rotator-cuff tears owing to mechanical instability. Indirect evidence is presented to link this pathology to ectopic production and secretion of bioactive bone morphogenetic proteins (BMPs) from sites within the subacromial bursa. Surgically removed specimens of subacromial bursa tissue from patients with chronic tears of the rotator cuff were analyzed by immunohistochemistry and reverse transcription-PCR. Bioactive BMP was detected in bursa extracts by a bioassay based on induction of alkaline phosphatase in the osteogenic/myogenic cell line C2C12. Topical and differential expression of BMP-2/4 and BMP-7 mRNA and protein was found in bursa tissue. The bioassay of C2C12 cells revealed amounts of active BMP high enough to induce osteogenic cell types, and blocking BMP with specific antibodies or soluble BMP receptors Alk-3 and Alk-6 abolished the inductive properties of the extract. Sufficient information was gathered to explain how ectopic expression of BMP might induce tissue transformation into ectopic bone/cartilage and, therefore, promote structural degeneration of the rotator cuff. Early surgical removal of the subacromial bursa might present an option to interrupt disease progression. PMID:16719933

  7. Lack of Acid Sphingomyelinase Induces Age-Related Retinal Degeneration

    PubMed Central

    Wu, Bill X.; Fan, Jie; Boyer, Nicholas P.; Jenkins, Russell W.; Koutalos, Yiannis; Hannun, Yusuf A.; Crosson, Craig E.

    2015-01-01

    Background Mutations of acid sphingomyelinase (ASMase) cause Niemann–Pick diseases type A and B, which are fatal inherited lipid lysosomal storage diseases, characterized with visceral organ abnormalities and neurodegeneration. However, the effects of suppressing retinal ASMase expression are not understood. The goal of this study was to determine if the disruption of ASMase expression impacts the retinal structure and function in the mouse, and begin to investigate the mechanisms underlying these abnormalities. Methods Acid sphingomyelinase knockout (ASMase KO) mice were utilized to study the roles of this sphingolipid metabolizing enzyme in the retina. Electroretinogram and morphometric analysis were used to assess the retinal function and structure at various ages. Sphingolipid profile was determined by liquid chromatography-mass spectrometry. Western blots evaluated the level of the autophagy marker LC3-II. Results When compared to control animals, ASMase KO mice exhibited significant age-dependent reduction in ERG a- and b-wave amplitudes. Associated with these functional deficits, morphometric analysis revealed progressive thinning of retinal layers; however, the most prominent degeneration was observed in the photoreceptor and outer nuclear layer. Additional analyses of ASMase KO mice revealed early reduction in ERG c-wave amplitudes and increased lipofuscin accumulation in the retinal pigment epithelium (RPE). Sphingolipid analyses showed abnormal accumulation of sphingomyelin and sphingosine in ASMase KO retinas. Western blot analyses showed a higher level of the autophagosome marker LC3-II. Conclusions These studies demonstrate that ASMase is necessary for the maintenance of normal retinal structure and function. The early outer retinal dysfunction, outer segment degeneration, accumulation of lipofuscin and autophagosome markers provide evidence that disruption of lysosomal function contributes to the age-dependent retinal degeneration exhibited by ASMase KO mice. PMID:26168297

  8. Striatal degeneration impairs language learning: evidence from Huntington's disease

    PubMed Central

    De Diego-Balaguer, Ruth; Couette, Marylin; Dolbeau, Guillaume; Dürr, Alexandra; Youssov, Katia; Bachoud-Lévi, Anne-Catherine

    2008-01-01

    Although the role of the striatum in language processing is still largely unclear, a number of recent proposals have outlined its specific contribution. Different studies report evidence converging to a picture where the striatum may be involved in those aspects of rule-application requiring non-automatized behavior. This is the main characteristic of the earliest phases of language acquisition that require the online detection of distant dependencies and the creation of syntactic categories by means of rule learning. Learning of sequences and categorization processes in non-language domains has been known to require striatal recruitment. Thus, we hypothesized that the striatum should play a prominent role in the extraction of rules in learning a language. We studied 13 pre-symptomatic gene-carriers and 22 early stage patients of Huntington’s disease (HD), both characterized by a progressive degeneration of the striatum and 21 late stage patients HD (18 stages II, 2 stage III and 1 stage IV) where cortical degeneration accompanies striatal degeneration. When presented with a simplified artificial language where words and rules could be extracted, early stage HD patients (stage I) were impaired in the learning test, demonstrating a greater impairment in rule than word learning compared to the twenty age- and education- matched controls. HD patients at later stages were impaired both on word and rule learning. While spared in their overall performance, gene-carriers having learned a set of abstract artificial language rules were then impaired in the transfer of those rules to similar artificial language structures. The correlation analyses among several neuropsychological tests assessing executive function showed that rule learning correlated with tests requiring working memory and attentional control, while word learning correlated with a test involving episodic memory. These learning impairments significantly correlated with the bicaudate ratio. The overall results support striatal involvement in rule extraction from speech and suggest that language acquisition requires several aspects of memory and executive functions for word and rule learning. PMID:18842608

  9. Ghost Sites

    NSDL National Science Digital Library

    There is much on the Net that is living and vibrant, but there is also much that is dead, stuffed, or embalmed, as Steve Baldwin, former Pathfinder (discussed in the November 14, 1997 ScoutReport) writer likes to say. At this site Baldwin tracks notable embalmed, dead, or dying web sites. Each issue of Ghost Sites reviews five to ten such sites. Sites discussed include the latest Pathfinder out-of-date update on the Unibomber, the stillborn MecklerWeb, and Electric Minds (discussed in the November 22, 1996 Scout Report), abandoned by Howard Rheingold. Sites are rated from Dying in I.C.U. to Site is Stuffed, Embalmed and Ready for Internet Museum. Ironically, several of the sites discussed have been resurrected or metamorphosed since they were discussed, proving, if nothing else, that anything is possible in cyberspace. Note that clicking on discussed sites opens a new browser window.

  10. The effects of claudin 14 during early Wallerian degeneration after sciatic nerve injury

    PubMed Central

    Gong, Leilei; Zhu, Yun; Xu, Xi; Li, Huaiqin; Guo, Weimin; Zhao, Qin; Yao, Dengbing

    2014-01-01

    Claudin 14 has been shown to promote nerve repair and regeneration in the early stages of Wallerian degeneration (0–4 days) in rats with sciatic nerve injury, but the mechanism underlying this process remains poorly understood. This study reported the effects of claudin 14 on nerve degeneration and regeneration during early Wallerian degeneration. Claudin 14 expression was up-regulated in sciatic nerve 4 days after Wallerian degeneration. The altered expression of claudin 14 in Schwann cells resulted in expression changes of cytokines in vitro. Expression of claudin 14 affected c-Jun, but not Akt and ERK1/2 pathways. Further studies revealed that enhanced expression of claudin 14 could promote Schwann cell proliferation and migration. Silencing of claudin 14 expression resulted in Schwann cell apoptosis and reduction in Schwann cell proliferation. Our data revealed the role of claudin 14 in early Wallerian degeneration, which may provide new insights into the molecular mechanisms of Wallerian degeneration. PMID:25657736

  11. Mechanical overloading causes mitochondrial superoxide and SOD2 imbalance in chondrocytes resulting in cartilage degeneration

    PubMed Central

    Koike, Masato; Nojiri, Hidetoshi; Ozawa, Yusuke; Watanabe, Kenji; Muramatsu, Yuta; Kaneko, Haruka; Morikawa, Daichi; Kobayashi, Keiji; Saita, Yoshitomo; Sasho, Takahisa; Shirasawa, Takuji; Yokote, Koutaro; Kaneko, Kazuo; Shimizu, Takahiko

    2015-01-01

    Mechanical stress and aging are major risk factors of cartilage degeneration. Human studies have previously reported that oxidative damage increased, while SOD2 protein was reciprocally downregulated in osteoarthritic degenerated cartilage. However, it remains unclear whether mitochondrial superoxide imbalance in chondrocytes causes cartilage degeneration. We herein demonstrate that mechanical loading promoted mitochondrial superoxide generation and selective Sod2 downregulation in chondrocytes in vivo and that mitochondrial superoxide inducer also downregulated Sod2 expression in chondrocytes in vitro. A genetically manipulated model revealed that Sod2 deficiency in chondrocytes also resulted in mitochondrial superoxide overproduction and dysfunction, thus leading to cartilage degeneration. Intra-articular injection of a permeable antioxidant effectively suppressed the mechanical loading-induced mitochondrial superoxide generation and cartilage degeneration in mice. Our findings demonstrate that mitochondrial superoxide plays a pivotal role in the development and progression of osteoarthritis, and the mitochondrial superoxide balance may therefore be a promising target for the treatment of cartilage degeneration. PMID:26108578

  12. Peptide and steroid regulation of muscle degeneration in an insect.

    PubMed

    Schwartz, L M; Truman, J W

    1982-03-12

    Two types of cell death occur in the intersegmental muscles of the giant silkmoth Antheraea polyphemus. The first results from a slow atrophy of the fibers, and the second is a rapid, programmed dissolution of the muscle. Both types appear to be mediated by endocrine factors. The slow atrophy is brought about by the decline in the steroid molting hormone 20-hydroxyecdysone and can be prevented with exogenous steroid. The rapid degeneration is triggered by the peptide eclosion hormone, but the sensitivity of the muscle to the peptide depends on the history of exposure of the muscle to 20-hydroxyecdysone. PMID:6278594

  13. Tissue engineering strategies to study cartilage development, degeneration and regeneration.

    PubMed

    Bhattacharjee, Maumita; Coburn, Jeannine; Centola, Matteo; Murab, Sumit; Barbero, Andrea; Kaplan, David L; Martin, Ivan; Ghosh, Sourabh

    2015-04-01

    Cartilage tissue engineering has primarily focused on the generation of grafts to repair cartilage defects due to traumatic injury and disease. However engineered cartilage tissues have also a strong scientific value as advanced 3D culture models. Here we first describe key aspects of embryonic chondrogenesis and possible cell sources/culture systems for in vitro cartilage generation. We then review how a tissue engineering approach has been and could be further exploited to investigate different aspects of cartilage development and degeneration. The generated knowledge is expected to inform new cartilage regeneration strategies, beyond a classical tissue engineering paradigm. PMID:25174307

  14. The impact of nonlinearity on degenerate parametric amplifiers

    NASA Astrophysics Data System (ADS)

    Rhoads, Jeffrey F.; Shaw, Steven W.

    2010-06-01

    This work investigates the effects of system nonlinearities on degenerate parametric amplifiers. A simple, Duffing-type nonlinearity is appended to a representative equation of motion for a mechanical or electromechanical parametric amplifier, and classical perturbation methods are used to characterize the resulting effects on the amplifier's frequency response and performance. Ultimately, the work demonstrates that parametric amplification can be realized in nonlinear, dynamic-range limited systems, such as resonant micro- or nanosystems, but at the expense of performance degradation. Additionally, it is shown that nonlinear amplifiers can be operated above their linear instability threshold but that doing so results in bistable amplified responses.

  15. Familial spinocerebellar degeneration as an expression of adrenoleukodystrophy.

    PubMed Central

    Kobayashi, T; Noda, S; Umezaki, H; Goto, I; Suzuki, S; Kitaguchi, T; Kuroiwa, Y

    1986-01-01

    A family with adrenoleukodystrophy and clinical manifestations of spinocerebellar degeneration was studied. Two adult male first cousins showed progressive limb and truncal ataxia, slurred speech and spasticity of the extremities. Brain CT scans demonstrated atrophy of the pons and cerebellum, in both cases. Very long chain fatty acids in plasma and erythrocyte membranes were elevated in the affected patients and intermediately increased in an aunt and the mother of one patient, thereby indicating homozygotes and carriers of adrenoleukodystrophy, respectively. This unusual type of adrenoleukodystrophy seems to be transmitted as an X-linked recessive trait. PMID:3468205

  16. Present and possible therapies for age-related macular degeneration.

    PubMed

    Khan, Muhammad; Agarwal, Ketan; Loutfi, Mohamed; Kamal, Ahmed

    2014-01-01

    Age-related macular degeneration (AMD) is the most common cause of blindness in the elderly population worldwide and is defined as a chronic, progressive disorder characterized by changes occurring within the macula reflective of the ageing process. At present, the prevalence of AMD is currently rising and is estimated to increase by a third by 2020. Although our understanding of the several components underpinning the pathogenesis of this condition has increased significantly, the treatment options for this condition remain substantially limited. In this review, we outline the existing arsenal of therapies available for AMD and discuss the additional role of further novel therapies currently under investigation for this debilitating disease. PMID:25097787

  17. A Coherent Ising Machine Based On Degenerate Optical Parametric Oscillators

    NASA Astrophysics Data System (ADS)

    Wang, Zhe; Marandi, Alireza; Wen, Kai; Byer, Robert L.; Yamamoto, Yoshihisa

    2014-03-01

    A degenerate optical parametric oscillator network is proposed to solve the NP-hard problem of finding a ground state of the Ising model. The underlying operating mechanism originates from the bistable output phase of each oscillator and the inherent preference of the network in selecting oscillation modes with the minimum photon decay rate. Computational experiments are performed on all instances reducible to the NP-hard MAX-CUT problems on cubic graphs of order up to 20. The numerical results reasonably suggest the effectiveness of the proposed network. This project is supported by the FIRST program of Japanese Government. Zhe Wang is also grateful for the support from Stanford Graduate Fellowship.

  18. Complete population transfer in a degenerate 3-level atom

    E-print Network

    Kh. Yu. Rakhimov; J. H. McGuire; Kh. Kh. Shakov

    2003-06-23

    We find conditions required to achieve complete population transfer, via coherent population trapping, from an initial state to a designated final state at a designated time in a degenerate 3-level atom, where transitions are caused by an external interaction. Complete population transfer from an initially occupied state 1 to a designated state 2 occurs under two conditions. First, there is a constraint on the ratios of the transition matrix elements of the external interaction. Second, there is a constraint on the action integral over the interaction, or "area", corresponding to the phase shift induced by the external interaction. Both conditions may be expressed in terms of simple odd integers.

  19. Degenerate quantum codes and the quantum Hamming bound

    NASA Astrophysics Data System (ADS)

    Sarvepalli, Pradeep; Klappenecker, Andreas

    2010-03-01

    The parameters of a nondegenerate quantum code must obey the Hamming bound. An important open problem in quantum coding theory is whether the parameters of a degenerate quantum code can violate this bound for nondegenerate quantum codes. In this article we show that Calderbank-Shor-Steane (CSS) codes, over a prime power alphabet q?5, cannot beat the quantum Hamming bound. We prove a quantum version of the Griesmer bound for the CSS codes, which allows us to strengthen the Rains’ bound that an [[n,k,d

  20. Degenerate quantum codes and the quantum Hamming bound

    SciTech Connect

    Sarvepalli, Pradeep [Department of Physics and Astronomy, University of British Columbia, Vancouver V6T 1Z1 (Canada); Klappenecker, Andreas [Department of Computer Science, Texas A and M University, College Station, Texas 77843 (United States)

    2010-03-15

    The parameters of a nondegenerate quantum code must obey the Hamming bound. An important open problem in quantum coding theory is whether the parameters of a degenerate quantum code can violate this bound for nondegenerate quantum codes. In this article we show that Calderbank-Shor-Steane (CSS) codes, over a prime power alphabet q{>=}5, cannot beat the quantum Hamming bound. We prove a quantum version of the Griesmer bound for the CSS codes, which allows us to strengthen the Rains' bound that an [[n,k,d

  1. Present and Possible Therapies for Age-Related Macular Degeneration

    PubMed Central

    Kamal, Ahmed

    2014-01-01

    Age-related macular degeneration (AMD) is the most common cause of blindness in the elderly population worldwide and is defined as a chronic, progressive disorder characterized by changes occurring within the macula reflective of the ageing process. At present, the prevalence of AMD is currently rising and is estimated to increase by a third by 2020. Although our understanding of the several components underpinning the pathogenesis of this condition has increased significantly, the treatment options for this condition remain substantially limited. In this review, we outline the existing arsenal of therapies available for AMD and discuss the additional role of further novel therapies currently under investigation for this debilitating disease. PMID:25097787

  2. Degenerate horizons, Einstein metrics, and Lens space bundles

    NASA Astrophysics Data System (ADS)

    Kunduri, Hari K.; Lucietti, James

    2014-12-01

    We present a new infinite class of near-horizon geometries of degenerate horizons, satisfying Einstein's equations for all odd dimensions greater than five. The symmetry and topology of these solutions is compatible with those of black holes. The simplest examples give horizons of spatial topology S3 ×S2 or the non-trivial S3-bundle over S2. More generally, the horizons are Lens space bundles associated to certain principal torus-bundles over Fano Kähler-Einstein manifolds. We also consider the classification problem for Einstein metrics on such Lens space bundles and derive a family which unifies all the known examples (Sasakian and non-Sasakian).

  3. Extended thermodynamics of classical and degenerate ideal gases

    NASA Astrophysics Data System (ADS)

    Liu, I.-S.; Mueller, I.

    Details of the theoretical basis of the field theory of extended thermodynamics for determining the thirteen fields of mass, momentum, and energy densities, the stress deviator, and the heat flux are presented. The kinetic theory of gases is reviewed, together with analytical considerations of thermodynamic processes, the entropy principle, and hyperbolicity. The principle of material frame indifference is examined, and an evaluation is made of entropy inequality. Aspects of the concept of absolute temperature are explored, and the theory is applied to classical and degenerate gases. Mention is also made of small amplitude plane harmonic waves and techniques for performing a transition from extended thermodynamics to ordinary thermodynamics.

  4. The mass ratio distribution of short period double degenerate stars

    Microsoft Academic Search

    P. F. L. Maxted; T. R. Marsh; C. K. J. Moran

    2002-01-01

    Short period double degenerates (DDs) are close white dwarf - white dwarf\\u000abinary stars which are the result of the evolution of interacting binary stars.\\u000aWe present the first definitive measurements of the mass ratio for two DDs,\\u000aWD0136+768 and WD1204+450, and an improved measurement of the mass ratio for\\u000aWD0957-666. We compare the properties of the 6 known DDs

  5. Disorder-induced neutral solitons in degenerate ground state polymers

    E-print Network

    Marc Thilo Figge; Maxim V. Mostovoy; Jasper Knoester

    1998-11-17

    In this letter, we study the effects of weak off-diagonal disorder on conjugated polymers with a doubly degenerate ground-state. We find that disorder induces a finite density of neutral solitons in the lattice dimerization of a polymer chain. Interchain interactions result in a linear potential between the solitons and, if sufficiently strong, bind them into pairs resulting in an exponential suppression of the soliton density. As neutral solitons carry spin 1/2, they contribute to the polymer's magnetic properties. We calculate the magnetic susceptibility and suggest measurements of the magnetic susceptibility in {\\it trans}-polyacetylene at low temperatures.

  6. Fluoro-Jade B: a high affinity fluorescent marker for the localization of neuronal degeneration

    Microsoft Academic Search

    Larry C Schmued; Keri J Hopkins

    2000-01-01

    Fluoro-Jade B, like its predecessor Fluoro-Jade, is an anionic fluorescein derivative useful for the histological staining of neurons undergoing degeneration. However, Fluoro-Jade B has an even greater specific affinity for degenerating neurons. This notion is supported by the conspicuous staining of degenerating neuronal elements with minimal background staining. This improved signal-to-noise ratio means that fine neuronal processes including distal dendrites,

  7. Fluoro-Jade: a novel fluorochrome for the sensitive and reliable histochemical localization of neuronal degeneration

    Microsoft Academic Search

    Larry C. Schmued; Christopher Albertson; William Slikker Jr

    1997-01-01

    Fluoro-Jade is an anionic fluorochrome capable of selectively staining degenerating neurons in brain slices. The histochemical application of Fluoro-Jade results in a simple, sensitive and reliable method for staining degenerating neurons and their processes. The technique will detect neuronal degeneration resulting from exposure to a variety of neurotoxic insults. Fluoro-Jade can be combined with other fluorescent methodologies including immunofluorescence, fluorescent

  8. Matrix elements of doubly degenerate vibrations and the Herzberg–Teller series

    Microsoft Academic Search

    W. L. Smith

    2011-01-01

    The non-zero terms in doubly degenerate vibrations in the Herzberg–Teller series are discussed and simplified formulae for the matrix elements for transitions between the degenerate l-components of such vibrational levels in upper and lower electronic states are given, with the emphasis on the change of vibrational frequency accompanying the transition. The results are applied to the analysis of degenerate components

  9. Matrix elements of doubly degenerate vibrations and the Herzberg-Teller series

    Microsoft Academic Search

    W. L. Smith

    2011-01-01

    The non-zero terms in doubly degenerate vibrations in the Herzberg-Teller series are discussed and simplified formulae for the matrix elements for transitions between the degenerate l-components of such vibrational levels in upper and lower electronic states are given, with the emphasis on the change of vibrational frequency accompanying the transition. The results are applied to the analysis of degenerate components

  10. A novel platform for minimally invasive delivery of cellular therapy as a thin layer across the subretina for treatment of retinal degeneration

    NASA Astrophysics Data System (ADS)

    Rotenstreich, Ygal; Tzameret, Adi; Kalish, Sapir E.; Belkin, Michael; Meir, Amilia; Treves, Avraham J.; Nagler, Arnon; Sher, Ifat

    2015-03-01

    Incurable retinal degenerations affect millions worldwide. Stem cell transplantation rescued visual functions in animal models of retinal degeneration. In those studies cells were transplanted in subretinal "blebs", limited number of cells could be injected and photoreceptor rescue was restricted to areas in proximity to the injection sites. We developed a minimally-invasive surgical platform for drug and cell delivery in a thin layer across the subretina and extravascular spaces of the choroid. The novel system is comprised of a syringe with a blunt-tipped needle and an adjustable separator. Human bone marrow mesenchymal stem cells (hBM-MSCs) were transplanted in eyes of RCS rats and NZW rabbits through a longitudinal triangular scleral incision. No immunosuppressants were used. Retinal function was determined by electroretinogram analysis and retinal structure was determined by histological analysis and OCT. Transplanted cells were identified as a thin layer across the subretina and extravascular spaces of the choroid. In RCS rats, cell transplantation delayed photoreceptor degeneration across the entire retina and significantly enhanced retinal functions. No retinal detachment or choroidal hemorrhages were observed in rabbits following transplantation. This novel platform opens a new avenue for drug and cell delivery, placing the transplanted cells in close proximity to the damaged RPE and retina as a thin layer, across the subretina and thereby slowing down cell death and photoreceptor degeneration, without retinal detachment or choroidal hemorrhage. This new transplantation system may increase the therapeutic effect of other cell-based therapies and therapeutic agents. This study is expected to directly lead to phase I/II clinical trials for autologous hBM-MSCs transplantation in retinal degeneration patients.

  11. Three dimensional electrostatic solitary waves in a dense magnetoplasma with relativistically degenerate electrons

    SciTech Connect

    Ata-ur-Rahman,; Qamar, A. [Institute of Physics and Electronics, University of Peshawar, Peshawar 25000 (Pakistan) [Institute of Physics and Electronics, University of Peshawar, Peshawar 25000 (Pakistan); National Centre for Physics, QAU Campus, Shahdrah Valley Road, Islamabad 44000 (Pakistan); Masood, W. [National Centre for Physics, QAU Campus, Shahdrah Valley Road, Islamabad 44000 (Pakistan) [National Centre for Physics, QAU Campus, Shahdrah Valley Road, Islamabad 44000 (Pakistan); COMSATS, Institute of Information Technology, Park Road, Chak Shahzad, Islamabad 44000 (Pakistan); Eliasson, B. [Physics Department, University of Strathclyde, Glasgow G4 0NG, Scotland (United Kingdom)] [Physics Department, University of Strathclyde, Glasgow G4 0NG, Scotland (United Kingdom)

    2013-09-15

    In this paper, small but finite amplitude electrostatic solitary waves in a relativistic degenerate magnetoplasma, consisting of relativistically degenerate electrons and non-degenerate cold ions, are investigated. The Zakharov-Kuznetsov equation is derived employing the reductive perturbation technique and its solitary wave solution is analyzed. It is shown that only compressive electrostatic solitary structures can propagate in such a degenerate plasma system. The effects of plasma number density, ion cyclotron frequency, and direction cosines on the profiles of ion acoustic solitary waves are investigated and discussed at length. The relevance of the present investigation vis-a-vis pulsating white dwarfs is also pointed out.

  12. Detection and analysis of cartilage degeneration by spatially resolved streaming potentials

    E-print Network

    Buschmann, Michael

    with hyaluronic acid. The repulsive electrostatic forces between the GAG chains, entrapped via the aggregation; Cartilage degeneration; Arthritis Introduction Articular cartilage is a dense connective tissue cov- ering

  13. Growth Factors and Anticatabolic Substances for Prevention and Management of Intervertebral Disc Degeneration

    PubMed Central

    Longo, Umile Giuseppe; Petrillo, Stefano; Franceschetti, Edoardo; Maffulli, Nicola; Denaro, Vincenzo

    2012-01-01

    Intervertebral disc (IVD) degeneration is frequent, appearing from the second decade of life and progressing with age. Conservative management often fails, and patients with IVD degeneration may need surgical intervention. Several treatment strategies have been proposed, although only surgical discectomy and arthrodesis have been proved to be predictably effective. Biological strategies aim to prevent and manage IVD degeneration, improving the function and anabolic and reparative capabilities of the nucleus pulposus and annulus fibrosus cells and inhibiting matrix degradation. At present, clinical applications are still in their infancy. Further studies are required to clarify the role of growth factors and anticatabolic substances for prevention and management of intervertebral disc degeneration. PMID:25098367

  14. SITE RANK

    EPA Science Inventory

    Site rank is formulated for ranking the relative hazard of contamination sources and vulnerability of drinking water wells. Site rank can be used with a variety of groundwater flow and transport models....

  15. Cannabinoid CB2 receptor (CB2R) stimulation delays rubrospinal mitochondrial-dependent degeneration and improves functional recovery after spinal cord hemisection by ERK1/2 inactivation.

    PubMed

    Latini, L; Bisicchia, E; Sasso, V; Chiurchiù, V; Cavallucci, V; Molinari, M; Maccarrone, M; Viscomi, M T

    2014-01-01

    Spinal cord injury (SCI) is a devastating condition of CNS that often results in severe functional impairments for which there are no restorative therapies. As in other CNS injuries, in addition to the effects that are related to the primary site of damage, these impairments are caused by degeneration of distal regions that are connected functionally to the primary lesion site. Modulation of the endocannabinoid system (ECS) counteracts this neurodegeneration, and pharmacological modulation of type-2 cannabinoid receptor (CB2R) is a promising therapeutic target for several CNS pathologies, including SCI. This study examined the effects of CB2R modulation on the fate of axotomized rubrospinal neurons (RSNs) and functional recovery in a model of spinal cord dorsal hemisection (SCH) at the cervical level in rats. SCH induced CB2R expression, severe atrophy, and cell death in contralateral RSNs. Furthermore, SCH affected molecular changes in the apoptotic cascade in RSNs - increased cytochrome c release, apoptosome formation, and caspase-3 activity. CB2R stimulation by its selective agonist JWH-015 significantly increased the bcl-2/bax ratio, reduced cytochrome c release, delayed atrophy and degeneration, and improved spontaneous functional recovery through ERK1/2 inactivation. These findings implicate the ECS, particularly CB2R, as part of the endogenous neuroprotective response that is triggered after SCI. Thus, CB2R modulation might represent a promising therapeutic target that lacks psychotropic effects and can be used to exploit ECS-based approaches to counteract neuronal degeneration. PMID:25188514

  16. Rare earth nanoparticles prevent retinal degeneration induced by intracellular peroxides:

    NASA Astrophysics Data System (ADS)

    Chen, Junping; Patil, Swanand; Seal, Sudipta; McGinnis, James F.

    2006-11-01

    Photoreceptor cells are incessantly bombarded with photons of light, which, along with the cells' high rate of oxygen metabolism, continuously exposes them to elevated levels of toxic reactive oxygen intermediates (ROIs). Vacancy-engineered mixed-valence-state cerium oxide nanoparticles (nanoceria particles) scavenge ROIs. Our data show that nanoceria particles prevent increases in the intracellular concentrations of ROIs in primary cell cultures of rat retina and, in vivo, prevent loss of vision due to light-induced degeneration of photoreceptor cells. These data indicate that the nanoceria particles may be effective in inhibiting the progression of ROI-induced cell death, which is thought to be involved in macular degeneration, retinitis pigmentosa and other blinding diseases, as well as the ROI-induced death of other cell types in diabetes, Alzheimer's disease, atherosclerosis, stroke and so on. The use of nanoceria particles as a direct therapy for multiple diseases represents a novel strategy and suggests that they may represent a unique platform technology.

  17. Rare earth nanoparticles prevent retinal degeneration induced by intracellular peroxides.

    PubMed

    Chen, Junping; Patil, Swanand; Seal, Sudipta; McGinnis, James F

    2006-11-01

    Photoreceptor cells are incessantly bombarded with photons of light, which, along with the cells' high rate of oxygen metabolism, continuously exposes them to elevated levels of toxic reactive oxygen intermediates (ROIs). Vacancy-engineered mixed-valence-state cerium oxide nanoparticles (nanoceria particles) scavenge ROIs. Our data show that nanoceria particles prevent increases in the intracellular concentrations of ROIs in primary cell cultures of rat retina and, in vivo, prevent loss of vision due to light-induced degeneration of photoreceptor cells. These data indicate that the nanoceria particles may be effective in inhibiting the progression of ROI-induced cell death, which is thought to be involved in macular degeneration, retinitis pigmentosa and other blinding diseases, as well as the ROI-induced death of other cell types in diabetes, Alzheimer's disease, atherosclerosis, stroke and so on. The use of nanoceria particles as a direct therapy for multiple diseases represents a novel strategy and suggests that they may represent a unique platform technology. PMID:18654167

  18. Testing the single degenerate channel for supernova Ia

    NASA Astrophysics Data System (ADS)

    Parsons, Steven

    2014-10-01

    The progenitors of supernova Ia are close binaries containing white dwarfs. Of crucial importance to the evolution of these systems is how much material the white dwarf can stably accrete and hence grow in mass. This occurs during a short-lived intense phase of mass transfer known as the super soft source (SSS) phase. The short duration of this phase and large extinction to soft X-rays means that only a handful are known in our Galaxy. Far more can be learned from the underlying SSS progenitor population of close white dwarf plus FGK type binaries. Unfortunately, these systems are hard to find since the main-sequence stars completely outshine the white dwarfs at optical wavelengths. Because of this, there are currently no known close white dwarf binaries with F, G or early K type companions, making it impossible to determine the contribution of the single degenerate channel towards supernova Ia. Using the GALEX and RAVE surveys we have now identified the first large sample of FGK stars with UV excesses, a fraction of which are these illusive, close systems. Following an intense ground based spectroscopic investigation of these systems, we have identified 5 definite close binaries, with periods of less than a few days. Here we apply for COS spectroscopic observations to measure the mass and temperature of the white dwarfs in order to determine the future evolution of these systems. This will provide a crucial test for the single degenerate channel towards supernova Ia.

  19. Muscle fibre breakdown in venom-induced muscle degeneration

    PubMed Central

    Harris, JB; Vater, R; Wilson, M; Cullen, MJ

    2003-01-01

    We studied the early stages of the degeneration of skeletal muscles using the venom of Notechis scutatus as the myotoxic agent. The venom was used at a dose equivalent to the LD50 in the mouse. There was no mortality amongst the rats. Electron microscopy was used to show the progressive hypercontraction of sarcomeres and the loss of alignment of myofibrils in individual muscle fibres. Between areas of hypercontraction sarcomeres were torn, shedding loosened myofilaments into the cytosol. Western blotting and Coomassie staining were used to compare the respective rates of loss of desmin, titin, actin, myosin and dystrophin. We showed that desmin and titin were the first proteins to be degraded with a time to 50% loss of approximately 1 h and 3 h, respectively. The loss of major contractile proteins, myosin and actin, was rather slower. The loss of dystrophin was also slower than the loss of desmin and titin. Early damage to the plasma membrane of the muscle fibre caused the cells to depolarize, probably promoting the hypercontraction of the sarcomeres, but actual loss of membrane was incomplete even at 24 h. We suggest that the early degradation of desmin and titin was responsible for the disaggregation of the sarcomeres; the liberated contractile proteins myosin and actin were shed into the cytosol, where they were degraded. Phagocytic cells that had invaded the degenerating muscle fibres were primarily involved in the clearance of damaged mitochondria. PMID:12739614

  20. Dwarf spheroidal galaxies as degenerate gas of free fermions

    E-print Network

    Valerie Domcke; Alfredo Urbano

    2014-12-16

    In this paper we analyze a simple scenario in which Dark Matter (DM) consists of free fermions with mass $m_f$. We assume that on galactic scales these fermions are capable of forming a degenerate Fermi gas, in which stability against gravitational collapse is ensured by the Pauli exclusion principle. The mass density of the resulting configuration is governed by a non-relativistic Lane-Emden equation, thus leading to a universal cored profile that depends only on one free parameter in addition to $m_f$. After reviewing the basic formalism, we test this scenario against experimental data describing the velocity dispersion of the eight classical dwarf spheroidal galaxies of the Milky Way. We find that, despite its extreme simplicity, the model exhibits a good fit to the data and realistic predictions for the size of DM halos providing that $m_f\\simeq 200$ eV. Furthermore, we show that in this setup larger galaxies correspond to the non-degenerate limit of the gas. We propose a concrete realization of this model in which DM is produced non-thermally via inflaton decay. We show that imposing the correct relic abundance and the bound on the free-streaming length constrains the inflation model in terms of inflaton mass, its branching ratio into DM and the reheating temperature.

  1. Atorvastatin treatment attenuates motor neuron degeneration in wobbler mice.

    PubMed

    Iwamoto, Konosuke; Yoshii, Yasuhiro; Ikeda, Ken

    2009-01-01

    We aimed to study whether atorvastatin treatment can retard motor neuron degeneration in wobbler mice. Wobbler mice and their normal littermates were fed 0.01% atorvastatin-mixed food (10 mg/kg/day) or regular food from age 3-4 weeks of disease onset for four weeks (n=10/group) or more than eight weeks (n=10/group). Motor function was evaluated by pull-strength and deformity scale of the forelimbs. For those symptomatic assessment and body weight were measured weekly. Neuropathological and biochemical changes of the biceps muscle and the cervical cord were analyzed at four weeks after treatment. Compared to vehicle, atorvastatin-treated wobbler mice delayed progression of forelimb motor deficits by more than four weeks. Wobbler mice significantly increased body weight from three weeks post-treatment of atorvastatin, compared with vehicle (p<0.05). Atorvastatin administration suppressed denervation atrophy at 30% (p<0.01), maintained choline acetyl transferase activities of the biceps muscle (p<0.05), and attenuated approximately 30% loss of motor neurons in wobbler mice (p<0.01). Atorvastatin fed to normal littermates did not influence body weight gain, neuropathological and biochemical findings. These data suggest that atorvastatin has neuroprotective effects on denervating muscles and degenerating motor neurons in wobbler mice. PMID:19922131

  2. Bright cyclic light accelerates photoreceptor cell degeneration in tubby mice.

    PubMed

    Kong, Li; Li, Feng; Soleman, Charles E; Li, Sheng; Elias, Rajesh V; Zhou, Xiaohong; Lewis, David A; McGinnis, James F; Cao, Wei

    2006-03-01

    Photoreceptor cell death is an irreversible, pathologic event in many blinding retinal diseases including retinitis pigmentosa, age-related macular disease, and retinal detachment. Light exposure can exacerbate a variety of human retinal diseases by increasing the rate of photoreceptor cell death. In the present study, we characterize the kinetics of photoreceptor cell death in Tubby (homozygous tub/tub, which have inherited, progressive retinal degeneration) mice born and raised in a bright cyclic light environment. Our data show that raising tub/tub mice in a bright cyclic light environment induces rapid loss of photoreceptors. This effect can be slowed, but not prevented, by raising animals in constant darkness, which suggests the involvement of phototransduction in the accelerated death of photoreceptors in this animal. We further demonstrated that the activities of cytosolic cytochrome c and caspases-3 and -9 were significantly increased in the retinas of tub/tub mice. Raising animals in darkness significantly reduced the increased activities of caspases-3 and -9, as well as cytosolic cytochrome c. We also observed that rhodopsin, a phototransduction protein, is not restricted to the rod outer segment, but is distributed throughout the rod cell, including the inner segments, cell bodies, and synapses. In addition, the light-dependent translocation and compartmentalization of arrestin and transducin are affected by the tubby mutation. Our results support the interpretation that problems in protein trafficking in the photoreceptors of the tub/tub mouse may contribute to retinal degeneration. PMID:16216520

  3. Present and future treatment possibilities in macular degeneration

    NASA Astrophysics Data System (ADS)

    Fisher, E.; Wegner, A.; Pfeiler, T.; Mertz, M.

    2005-11-01

    Purpose: To discuss present and future treatment possibilities in different types of choroidal neovascularisation. Methods: Presented are angiographic- and OCT-findings in patients with macular degeneration of different origin. Choroidal neovascularisations, which are not likely to respond positively to established procedures like thermal laser coagulation or photodynamic therapy will be discussed. Results and conclusions: Present study-guidelines and new methods of pharmacological intervention are analysed in different patterns of macular degeneration. Conventional laser coagulation in the treatment of classic, extrafoveal CNV and photodynamic therapy of predominantly classic subfoveal CNV still represent a gold standard. There are new recommendations, loosening the tight criteria of the TAP and VIP-guidelines, which cover, for instance, wider visual acuity ranges and the treatment of juxtafoveally located choroidal neovascularisations. Positive findings in literature confirm the role of PDT in pathologic myopia and other non-AMD CNV. Studies about surgical procedures, like macula- or RPE-translocation after surgical removal or thermal laser destruction of the CNV are in progress and are expected to show promising results. Phase II/III studies will soon point out the effect of anti-VEGF agents. The application of intravitreal (triamcinolone) or peribulbar (anecortave acetat) steroids could be useful. The combination with surgical or laser techniques could bring further benefit to the patient.

  4. Dwarf spheroidal galaxies as degenerate gas of free fermions

    NASA Astrophysics Data System (ADS)

    Domcke, Valerie; Urbano, Alfredo

    2015-01-01

    In this paper we analyze a simple scenario in which Dark Matter (DM) consists of free fermions with mass mf. We assume that on galactic scales these fermions are capable of forming a degenerate Fermi gas, in which stability against gravitational collapse is ensured by the Pauli exclusion principle. The mass density of the resulting con figuration is governed by a non-relativistic Lane-Emden equation, thus leading to a universal cored profile that depends only on one free parameter in addition to mf. After reviewing the basic formalism, we test this scenario against experimental data describing the velocity dispersion of the eight classical dwarf spheroidal galaxies of the Milky Way. We find that, despite its extreme simplicity, the model exhibits a good fit to the data and realistic predictions for the size of DM halos providing that mfsimeq 200 eV. Furthermore, we show that in this setup larger galaxies correspond to the non-degenerate limit of the gas. We propose a concrete realization of this model in which DM is produced non-thermally via inflaton decay. We show that imposing the correct relic abundance and the bound on the free-streaming length constrains the inflation model in terms of inflaton mass, its branching ratio into DM and the reheating temperature.

  5. Reduction of GABA/sub B/ receptor binding induced by climbing fiber degeneration in the rat cerebellum

    SciTech Connect

    Kato, K.; Fukuda, H.

    1985-07-22

    When the rat cerebellar climbing fibers degenerated, as induced by lesioning the inferior olive with 3-acetylpyridine (3-AP), GABA/sub B/ receptor binding determined with /sup 3/H-(+/-)baclofen was reduced in the cerebellum but not in the cerebral cortex of rats. Computer analysis of saturation data revealed two components of the binding sites, and indicated that decrease of the binding in the cerebellum was due to reduction in receptor density, mainly of the high-affinity sites, the B/sub max/ of which was reduced to one-third that in the control animals. In vitro treatment with 3-AP, of the membranes prepared from either the cerebellum or the cerebral cortex, induced no alteration in the binding sites, thereby indicating that the alteration of GABA/sub B/ sites induced by in vivo treatment with 3-AP is not due to a direct action of 3-AP on the receptor. GABA/sub A/ and benzodiazepine receptor binding labelled with /sup 3/H-muscimol and /sup 3/H-diazepam, respectively, in both of brain regions was not affected by destruction of the inferior olive. These results provide evidence that some of the GABA/sub B/ sites but neither GABA/sub A/ nor benzodiazepine receptors in the cerebellum are located at the climbing fiber terminals. 28 references, 4 figures, 2 tables.

  6. 3-acetylpyridine-induced degeneration in the adult ascidian neural complex: Reactive and regenerative changes in glia and blood cells.

    PubMed

    Medina, Bianca N S P; Santos de Abreu, Isadora; Cavalcante, Leny A; Silva, Wagner A B; da Fonseca, Rodrigo N; Allodi, Silvana; de Barros, Cintia M

    2015-08-01

    Ascidians are interesting neurobiological models because of their evolutionary position as a sister-group of vertebrates and the high regenerative capacity of their central nervous system (CNS). We investigated the degeneration and regeneration of the cerebral ganglion complex of the ascidian Styela plicata following injection of the niacinamide antagonist 3-acetylpyridine (3AP), described as targeting the CNS of several vertebrates. For the analysis and establishment of a new model in ascidians, the ganglion complex was dissected and prepared for transmission electron microscopy (TEM), routine light microscopy (LM), immunohistochemistry and Western blotting, 1 or 10 days after injection of 3AP. The siphon stimulation test (SST) was used to quantify the functional response. One day after the injection of 3AP, CNS degeneration and recruitment of a non-neural cell type to the site of injury was observed by both TEM and LM. Furthermore, weaker immunohistochemical reactions for astrocytic glial fibrillary acidic protein (GFAP) and neuronal ?III-tubulin were observed. In contrast, the expression of caspase-3, a protein involved in the apoptotic pathway, and the glycoprotein CD34, a marker for hematopoietic stem cells, increased. Ten days after the injection of 3AP, the expression of markers tended toward the original condition. The SST revealed attenuation and subsequent recovery of the reflexes from 1 to 10 days after 3AP. Therefore, we have developed a new method to study ascidian neural degeneration and regeneration, and identified the decreased expression of GFAP and recruitment of blood stem cells to the damaged ganglion as reasons for the success of neuroregeneration in ascidians. © 2014 Wiley Periodicals, Inc. Develop Neurobiol 75: 877-893, 2015. PMID:25484282

  7. STUDIES UPON CALCAREOUS DEGENERATION : I. THE PROCESS OF PATHOLOGICAL CALCIFICATION.

    PubMed

    Klotz, O

    1905-11-25

    IT WILL BE SEEN FROM THE ABOVE THAT WE HAVE STUDIED THE CONDITIONS ASSOCIATED WITH THE DEPOSIT OF CALCAREOUS SALTS: (I) in connection with normal and pathological ossification, and (2) in pathological calcification as exhibited in (a) atheroma of the vessels; (b) calcification of caseating tubercular lesions; (c) calcification of inflammatory new growth, and (d) degenerating tumors; and we have induced experimentally deposits of calcareous salts in the lower animals: (a) within celloidin capsules containing fats and soaps; (b) in the kidney, and (c) in connection with fat necrosis. I. We have found that bone formation and pathological calcareous infiltration are wholly distinct processes. In the former there is no evidence of associated fatty change, and the cells associated with the process of deposition of calcium are functionally active. In the latter there is an antecedent fatty change in the affected areas, and the cells involved present constant evidences of degeneration. The view that would seem to account best for the changes observed in the latter case is that with lowered vitality the cells are unable to utilize the products brought to them by the blood, or which they continue to absorb, so that the normal series of decompositions associated with their metabolism fails to take place and hence they interact among themselves in the cytoplasm with the result that insoluble compounds replace soluble ones. II. Besides the fact that calcification is always preceded by fatty change within the cells, another fact should be emphasized. namely: that combination of the fats present with calcium salts to form calcium soaps tends to occur. The stages immediately preceding these are difficult to follow with anything approaching certainty, perhaps because the earlier stages vary under different conditions. In fat necrosis, for instance, the cells affected are normally storehouses for neutral fats, and as long as they remain healthy neutral fats alone are present in them. When they are subjected to the action of the pancreatic juice with its fat-splitting ferment the cells are killed and coincidently the neutral fats are decomposed, fatty acids being deposited. The fatty acids now slowly combine with the calcium salts. In degenerating lipomata the process would seem to be similar. But in other cases the cells are not obviously fat-containing in the normal state; nevertheless prior to calcification they undergo so-called fatty degeneration, which is really a form of cell degeneration accompanied by fat infiltration. As regards the source of the cell fats in general we may safely accept: 1. That fats are transported in the blood as diffusible soaps. 2. That taken up by the cells these soaps may either- (a) Be reconverted into neutral fats and become stored in the cytoplasm as such, or (b) undergo assimilation proper, becoming part and parcel of the cell substance, in which case they are not recognizable by the ordinary microchemical tests. 3. If these two possibilities be accepted it follows that the appearance of fats and soaps in the degenerating cell may be due to either- (a) Absorption or infiltration of soaps from the surrounding medium, the degenerating cell retaining the power of splitting off the fat but being unable to utilize this in metabolism. (b) Cytoplasmic disintegration with dissociation of the soap-albumen combination or, more broadly, liberation of the fats from their combination with the cytoplasm. The appearances seen in the cells of atheromatous areas indicate that the first of these does occur. III. In areas undergoing calcareous infiltration we have demonstrated. the presence of soaps, and this often in such quantities that they can be isolated and estimated by gross chemical methods. By microchemical methods also we have been able to show that after removing all the neutral fats and fatty acids by petroleum ether there remains behind a substance giving with Sudan III the reaction we associate with the presence of soap. And experimentally we have produced these soaps within the organism, more particularly

  8. Disease Sequence from Mutant Rhodopsin Allele to Rod and Cone Photoreceptor Degeneration in Man

    Microsoft Academic Search

    Artur V. Cideciyan; Donald C. Hood; Yijun Huang; Eyal Banin; Zong-Yi Li; Edwin M. Stone; Ann H. Milam; Samuel G. Jacobson

    1998-01-01

    Mutations in the gene encoding rhodopsin, the visual pigment in rod photoreceptors, lead to retinal degeneration in species from Drosophila to man. The pathogenic sequence from rod cell-specific mutation to degeneration of rods and cones remains unclear. To understand the disease process in man, we studied heterozygotes with 18 different rhodopsin gene mutations by using noninvasive tests of rod and

  9. Prematurely senescent ARPE-19 cells display features of age-related macular degeneration

    Microsoft Academic Search

    Anne-Lise Glotin; Florence Debacq-Chainiaux; Jean-Yves Brossas; Anne-Marie Faussat; Jacques Tréton; Anna Zubielewicz; Olivier Toussaint; Frédéric Mascarelli

    2008-01-01

    The etiology of age-related macular degeneration (AMD), the leading cause of blindness in the developed world, remains poorly understood, but may be related to cumulative oxidative stress. The prime target of the disease is the retinal pigmented epithelium (RPE). To study the molecular mechanisms underlying RPE degeneration, we investigated whether repetitive oxidative stress induced premature senescence in RPE cells from

  10. Fluoro-Jade C results in ultra high resolution and contrast labeling of degenerating neurons

    Microsoft Academic Search

    Larry C. Schmued; Chris C. Stowers; Andrew C. Scallet; Lulu Xu

    2005-01-01

    The causes and effects of neuronal degeneration are of major interest to a wide variety of neuroscientists. Paralleling this growing interest is an increasing number of methods applicable to the detection of neuronal degeneration. The earliest methods employing aniline dyes were methodologically simple, but difficult to interpret due to a lack of staining specificity. In an attempt to circumvent this

  11. Comparative and quantitative proteomic analysis of normal and degenerated human annulus fibrosus cells.

    PubMed

    Ye, Dongping; Liang, Weiguo; Dai, Libing; Zhou, Longqiang; Yao, Yicun; Zhong, Xin; Chen, Honghui; Xu, Jiake

    2015-05-01

    Degeneration of the intervertebral disc (IVD) is a major chronic medical condition associated with back pain. To better understand the pathogenesis of IVD degeneration, we performed comparative and quantitative proteomic analyses of normal and degenerated human annulus fibrosus (AF) cells and identified proteins that are differentially expressed between them. Annulus fibrosus cells were isolated and cultured from patients with lumbar disc herniation (the experimental group, degenerated AF cells) and scoliosis patients who underwent orthopaedic surgery (the control group, normal AF cells). Comparative proteomic analyses of normal and degenerated cultured AF cells were carried out using 2-D electrophoresis, mass spectrometric analyses, and database searching. Quantitative analyses of silver-stained 2-D electrophoresis gels of normal and degenerated cultured AF cells identified 10 protein spots that showed the most altered differential expression levels between the two groups. Among these, three proteins were decreased, including heat shock cognate 71-kDa protein, glucose-6-phosphate 1-dehydrogenase, and protocadherin-23, whereas seven proteins were increased, including guanine nucleotide-binding protein G(i) subunit ?-2, superoxide dismutase, transmembrane protein 51, adenosine receptor A3, 26S protease regulatory subunit 8, lipid phosphate phosphatase-related protein, and fatty acyl-crotonic acid reductase 1. These differentially expressed proteins might be involved in the pathophysiological process of IVD degeneration and have potential values as biomarkers of the degeneration of IVD. PMID:25739836

  12. Fibroid degeneration in a postmenopausal woman presenting as an acute abdomen

    PubMed Central

    Shrestha, Rajesh; Khanal, Raju; Aryal, Madan Raj; Pathak, Ranjan; Karmacharya, Paras; Naqi, Muniba; Murukutla, Srujitha; Bhatt, Vijaya Raj; Gottesman, Aaron

    2015-01-01

    Uterine fibroid, one of the most common tumors in women, is estrogen dependent, which commonly regresses after menopause. Fibroid degeneration after menopause, therefore, is rare. Here the authors report a case of 56-year-old postmenopausal woman who presented with acute abdominal pain, low grade fever, and leukocytosis as a result of fibroid degeneration. PMID:25656665

  13. Degenerate U-and V -statistics under ergodicity: Asymptotics, bootstrap and applications in statistics

    E-print Network

    Degenerate U- and V -statistics under ergodicity: Asymptotics, bootstrap and applications in statistics Anne Leucht Universit¨at Hamburg Fachbereich Mathematik, SPST Bundesstra�e 55 D-20146 Hamburg.neumann@uni-jena.de Abstract We derive the asymptotic distributions of degenerate U- and V -statistics of stationary

  14. ON THE GEOMETRIC GENUS OF REDUCIBLE SURFACES AND DEGENERATIONS OF SURFACES TO UNIONS OF PLANES

    E-print Network

    Miranda, Rick

    ON THE GEOMETRIC GENUS OF REDUCIBLE SURFACES AND DEGENERATIONS OF SURFACES TO UNIONS OF PLANES A;bre is a reduced, connected surface X #26; P r , r > 3, which is assumed to be a union of planes. Here in the 1940{ 50's regarding degenerations of scrolls to unions of planes and the computation of bounds

  15. A Nonlinear Master Equation for a Degenerate Diffusion Model of Biofilm Growth

    E-print Network

    Hillen, Thomas

    A Nonlinear Master Equation for a Degenerate Diffusion Model of Biofilm Growth Hassan Khassehkhan1@math.ualberta.ca Abstract. We present a continuous time/discrete space model of biofilm growth, starting from the semi models of biofilms. Grid refinement leads formally to a degenerate parabolic equation. We show that a set

  16. Treatment with trkC agonist antibodies delays disease progression in neuromuscular degeneration (nmd) mice

    Microsoft Academic Search

    Rocio Ruiz; John Lin; Alison Forgie; Davide Foletti; David Shelton; Arnon Rosenthal; Lucia Tabares

    2005-01-01

    Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is a fatal autosomal recessive disorder seen in infants. It is characterized by lower motor neuron degeneration, progressive muscle paralysis and respiratory failure, for which no effective treatment exists. The phenotype of neuromuscular degeneration (nmd) mice closely resembles the human SMARD1. The identification of the mutated mouse gene in nmd mice

  17. Degenerate nDoping of Few-Layer Transition Metal Dichalcogenides by Potassium

    E-print Network

    California at Irvine, University of

    Degenerate nDoping of Few-Layer Transition Metal Dichalcogenides by Potassium Hui Fang,,,§ Mahmut semiconductors by surface charge transfer using potassium. High-electron sheet densities of 1.0 × 1013 cm-2 and 2: Degenerate doping, few-layer, TMDCs, MoS2, WSe2, potassium, surface charge transfer The desire for enhanced

  18. Clinicopathological correlation in exudative age related macular degeneration: histological differentiation between classic and occult choroidal neovascularisation

    Microsoft Academic Search

    B A Lafaut; K U Bartz-Schmidt; C Vanden Broecke; S Aisenbrey; J J De Laey; K Heimann

    2000-01-01

    AIMSTo analyse the histopathology of classic and occult choroidal neovascular membrane surgical specimens in age related macular degeneration.METHODS35 membranes, from a consecutive series of surgically removed choroidal neovascular membranes in age related macular degeneration, were classified as classic or occult following the guidelines of the Macular Photocoagulation Study. Membranes with classic as well as occult components were considered as mixed

  19. Mitochondrial dysfunction as a cause of axonal degeneration in multiple sclerosis patients

    Microsoft Academic Search

    Ranjan Dutta; Jennifer McDonough; Xinghua Yin; John Peterson; Ansi Chang; Thalia Torres; Tatyana Gudz; Wendy B. Macklin; David A. Lewis; Robert J. Fox; Richard Rudick; Karoly Mirnics; Bruce D. Trapp

    2006-01-01

    Objective: Degeneration of chronically demyelinated axons is a major cause of irreversible neurological disability in multiple sclerosis (MS) patients. Development of neuroprotective therapies will require elucidation of the molecular mechanisms by which neurons and axons degenerate. Methods: We report ultrastructural changes that support Ca2- mediated destruction of chronically demyelinated axons in MS patients. We compared expression levels of 33,000 char-

  20. A FINITE VOLUME SCHEME FOR NONLINEAR DEGENERATE PARABOLIC MARIANNE BESSEMOULIN-CHATARD AND FRANCIS FILBET

    E-print Network

    Boyer, Edmond

    A FINITE VOLUME SCHEME FOR NONLINEAR DEGENERATE PARABOLIC EQUATIONS MARIANNE BESSEMOULIN-CHATARD AND FRANCIS FILBET Abstract. We propose a second order finite volume scheme for nonlinear degenerate parabolic equations. For some of these models (porous media equation, drift-diffusion system for semiconductors

  1. Blow-up at the Boundary for Degenerate Semilinear Parabolic Equations

    E-print Network

    Floater, Michael S.

    Blow-up at the Boundary for Degenerate Semilinear Parabolic Equations M. S. Floater Department a superlinear parabolic equation, degenerate in the time derivative. It is shown that the solution may blow up in finite time. Moreover it is proved that for a large class of initial data blow-up occurs at the boundary

  2. Intravitreal Reinjection of Triamcinolone for Exudative Age-Related Macular Degeneration

    Microsoft Academic Search

    Jost B. Jonas; Imren Akkoyun; Wido M. Budde; Ingrid Kreissig; Robert F. Degenring

    2004-01-01

    Objective: To evaluate the outcome of repeated intra- vitreal injections of triamcinolone acetonide for the treat- ment of exudative age-related macular degeneration. Methods: This prospective, comparative nonrandom- ized clinical interventional study included 13 patients with progressive exudative age-related macular degeneration with occult, or predominantly occult, subfoveal neovas- cularization. All patients had shown an increase or sta- bilization of visual acuity

  3. Caregiver Burden in Frontotemporal Degeneration and Corticobasal Syndrome

    PubMed Central

    Armstrong, Nicole; Schupf, Nicole; Grafman, Jordan; Huey, Edward D.

    2015-01-01

    Background and Aims Caregiver stress is often a serious problem when caring for a patient with frontal lobe dysfunction. Methods A total of 102 caregivers of both patients with frontotemporal degeneration and corticobasal syndrome completed the Frontal Systems Behavior Scale (FrSBe) and the Zarit Burden Interview (ZBI). To analyze the association between apathy or disinhibition (or both) and caregiver burden, the effects of the total FrSBe and the apathy and disinhibition subscales of the FrSBE on the total ZBI score were assessed with logistic regressions and t tests. Results Total FrSBE score and the apathy FrSBE subscore predicted caregiver burden. Apathy occurred without disinhibition, and the two occurred together, but disinhibition without apathy was very rare. Conclusions Disinhibition without apathy occurred very rarely. Apathy was more associated with caregiver burden than disinhibition. PMID:24022248

  4. The Relationship between Subclinical Asperger's Syndrome and Frontotemporal Lobar Degeneration

    PubMed Central

    Midorikawa, Akira; Kawamura, Mitsuru

    2012-01-01

    Background/Aims The existence of the behavioral variant of frontotemporal dementia (bv-FTD), including senile Asperger's syndrome (AS), has been proposed. However, there are no empirical case reports to support the proposal. In this report, we present 3 patients who showed symptoms of bv-FTD and demonstrated signs of autistic spectrum disorder, especially AS. Methods We evaluated 3 subjects using the diagnostic criteria for bv-FTD, and their caregivers retrospectively provided data to calculate the Autism-Spectrum Quotient, Japanese version [Wakabayashi et al.: Shinrigaku Kenkyu 2004;75:78–84]. We also compared these data with those obtained from 3 individuals with Alzheimer's disease. Results All 3 patients met the criteria for bv-FTD and had a higher Autism-Spectrum Quotient score than did comparable Alzheimer's disease subjects. Conclusion It is possible that some senile persons with frontotemporal lobar degeneration-like maladaptive behavior may suffer from subclinical AS. PMID:22719743

  5. Retinal phagocytes in age-related macular degeneration

    PubMed Central

    Kim, Soo-Young

    2015-01-01

    Age-related macular degeneration (AMD) is the leading cause of blindness in industrial countries. Vision loss caused by AMD results from geographic atrophy (dry AMD) and/or choroidal neovascularization (wet AMD). Presently, the etiology and pathogenesis of AMD is not fully understood and there is no effective treatment. Oxidative stress in retinal pigment epithelial (RPE) cells is considered to be one of the major factors contributing to the pathogenesis of AMD. Also retinal glia, as scavengers, are deeply related with diseases and could play a role. Therefore, therapeutic approaches for microglia and Müller glia, as well as RPE, may lead to new strategies for AMD treatment. This review summarizes the pathological findings observed in RPE cells, microglia and Müller glia of AMD murine models.

  6. Phase conjugation by degenerate forward four-wave mixing

    NASA Astrophysics Data System (ADS)

    Khyzniak, A.; Kondilenko, V.; Kucherov, Iu.; Lesnik, S.; Odoulov, S.; Soskin, M.

    1984-02-01

    Phase conjugation (PC) that is due to degenerate forward four-wave mixing is studied both theoretically and experimentally. Similarity to backward four-wave mixing, the limiting efficiency of this process corresponds to the total energy transfer from each pump wave into the signal and conjugate waves, although in this case the Yariv oscillations do not occur. The numerical solution of the nonstationary problem is presented, revealing the transient oscillations of the PC-beam intensity with maxima many times exceeding the saturation value. PC of Q-switched and free-oscillating solid-state laser radiation is obtained by using the thermal nonlinearity of absorbing solutions. PC of CW laser radiation is obtained in a LiNbO3 crystal, the PC-beam intensity being six times larger than the initial intensity of the signal beam. The self-compensation of nonlinear phase distortions of the recording medium is demonstrated.

  7. Self-phase-locked degenerate femtosecond optical parametric oscillator.

    PubMed

    Wong, Samuel T; Plettner, Tomas; Vodopyanov, Konstantin L; Urbanek, Karel; Digonnet, Michel; Byer, Robert L

    2008-08-15

    We demonstrated a stable degenerate synchronously pumped femtosecond optical parametric oscillator (SPOPO) as a divide-by-2 subharmonic generator. The SPOPO exhibited passive all-optical self-phase-locking between the pump and signal/idler and thus required no external electronic feedback to produce the phase-locked subharmonic. We employed a type I phase-matched, 1-mm-long, periodically poled MgO:LiNbO3 crystal as the nonlinear gain element and an 80 MHz mode-locked Ti:sapphire laser with 180 fs pulses tuned at 775 nm as the pump. The SPOPO generated transform-limited 70 fs phase-locked output pulses centered at 1550 nm. The self-phase-locking operation was confirmed by separate beat-note measurement techniques with respect to the pump laser and with respect to an external cw laser. PMID:18709125

  8. Dual quantum information splitting with degenerate graph states

    E-print Network

    Akshata Shenoy H.; R. Srikanth; T. Srinivas

    2013-02-04

    We propose a protocol for secret sharing, called dual quantum information splitting (DQIS), that reverses the roles of state and channel in standard quantum information splitting. In this method, a secret is shared via teleportation of a fiducial input state over an entangled state that encodes the secret in a graph state basis. By performing a test of violation of a Bell inequality on the encoded state, the legitimate parties determine if the violation is sufficiently high to permit distilling secret bits. Thus, the code space must be maximally and exclusively nonlocal. To this end, we propose two ways to obtain code words that are degenerate with respect to a Bell operator. The security of DQIS comes from monogamy of nonlocal correlations, which we illustrate by means of a simple single-qubit attack model. The nonlocal basis of security of our protocol makes it suitable for security in general monogamous theories and in the more stringent, device-independent cryptographic scenario.

  9. Quantum degenerate mixtures of strontium and rubidium atoms

    E-print Network

    Pasquiou, Benjamin; Tzanova, Slava; Stellmer, Simon; Szczepkowski, Jacek; Parigger, Mark; Grimm, Rudolf; Schreck, Florian

    2013-01-01

    We report on the realization of quantum degenerate gas mixtures of the alkaline-earth element strontium with the alkali element rubidium. A key ingredient of our scheme is sympathetic cooling of Rb by Sr atoms that are continuously laser cooled on a narrow linewidth transition. This versatile technique allows us to produce ultracold gas mixtures with a phase-space density of up to 0.06 for both elements. By further evaporative cooling we create double Bose-Einstein condensates of 87Rb with either 88Sr or 84Sr, reaching more than 10^5 condensed atoms per element for the 84Sr-87Rb mixture. These quantum gas mixtures constitute an important step towards the production of a quantum gas of polar, open-shell RbSr molecules.

  10. Differential Gene Expression in Age-Related Macular Degeneration.

    PubMed

    Morgan, Denise J; DeAngelis, Margaret M

    2014-10-23

    Gene expression is the first step in ascribing function between an associated gene and disease. Understanding how variation in a gene influences expression, particularly in tissues affected by the disease, may help elucidate what influences the phenotypic outcome of that disease. Previous studies of the genetics of age-related macular degeneration (AMD) have identified several risk factors, but have not yet bridged the gap between gene association and identifying a specific mechanism or function that is involved in the pathogenesis of AMD. Advances in genomic technologies, such as RNA sequencing (RNA-seq), single cell RNA-seq, bilsulfite sequencing, and/or whole genome methylation, will be powerful tools for identifying genes/pathways that are differentially expressed in those with AMD versus those without AMD. These technologies should advance the field of AMD research so that appropriate preventive and therapeutic targets can be developed. PMID:25342062

  11. Next generation therapeutic solutions for age-related macular degeneration

    PubMed Central

    Cunnsamy, Khrishen; Ufret-Vincenty, Rafael; Wang, Shusheng

    2013-01-01

    Age-related macular degeneration (AMD) is the primary cause of blindness among the elderly worldwide. To date, no cure is available, and the available palliative treatments only showed limited efficacy in improving visual acuity. The etiology of AMD remains elusive but research over the past decade has uncovered characteristic features of the disease. Known as the hallmarks of AMD, these features include (A) oxidative stress and RPE cytotoxicity; (B) loss of macromolecular permeability and hydraulic conductivity: (C) inflammation; (D) choroidal neovascularization and vascular leakage; and (E) loss of neuroprotection. Recent breakthrough in understanding the pathogenesis of AMD has spawned an array of novel therapeutic agents designed to address these hallmarks. Here we review the features of AMD and highlight the most promising therapeutic and diagnostic approaches based on the patents published from 2008 to 2011. Most likely, a next generation treatment for AMD will be developed from these emerging efforts. PMID:24040506

  12. Pharmacogenetics and nutritional supplementation in age-related macular degeneration

    PubMed Central

    Hampton, Blake M; Kovach, Jaclyn L; Schwartz, Stephen G

    2015-01-01

    The Age-Related Eye Disease Study (AREDS) recommended treatment with antioxidants plus zinc in patients with intermediate or advanced age-related macular degeneration in order to reduce progression risks. Recent pharmacogenetic studies have reported differences in treatment outcomes with respect to variants in genes for CFH and ARMS2, although the treatment recommendations based on these differences are controversial. Different retrospective analyses of subsets of patients from the same AREDS trial have drawn different conclusions. The practicing clinician, who is not an expert on genetics, clinical trial design, or statistical analysis, may be uncertain how to interpret these results. Based on the balance of the available literature, we suggest not changing established practice recommendations until additional evidence from clinical trials becomes available.

  13. Stem cells as tools in regenerative therapy for retinal degeneration

    PubMed Central

    Enzmann, Volker; Yolcu, Esma; Kaplan, Henry J.; Ildstad, Suzanne T.

    2011-01-01

    Objectives Regenerative medicine intends to provide therapies for severe injuries or chronic diseases where endogenous repair does not sufficiently restore the tissue. Pluripotent stem cells (SC), with their capacity to give rise to specialized cells, are the most promising candidates for clinical application. Despite encouraging results, a combination with up-to-date tissue engineering might be critical for ultimate success. Design The focus is on the use of SC for regeneration of retinal degenerations. Cell populations include embryonic, neural, and bone marrow-derived SC and engineered grafts will also be described. Results Experimental approaches have successfully replaced damaged photoreceptors and retinal pigment epithelium using endogenous and exogenous SC. Conclusions SC have the potential to significantly impact retinal regeneration. A combination with bioengineering may bear even greater promise. However, ethical and scientific issues have yet to be solved. PMID:19365041

  14. Paraneoplastic cerebellar degeneration associated with lymphoepithelial carcinoma of the tonsil

    PubMed Central

    2013-01-01

    Background Paraneoplastic cerebellar degeneration (PCD) is a classical tumor-associated, immune-mediated disease typically associated with gynecological malignancies, small-cell lung-cancer or lymphoma. Case presentation Here we present the case of a 38-year old male with an over 12 months rapidly progressive cerebellar syndrome. Extensive diagnostic workup revealed selective hypermetabolism of the right tonsil in whole-body PET. Histological examination after tonsillectomy demonstrated a lymphoepithelial carcinoma of the tonsil and the tongue base strongly suggesting a paraneoplastic cause of the cerebellar syndrome. To the best of our knowledge this is the first case of an association of a lymphoepithelial carcinoma, a rare pharyngeal tumor, with PCD. Conclusions In cases of classical paraneoplastic syndromes an extensive search for neoplasms should be performed including whole-body PET to detect tumors early in the course of the disease. PMID:24134642

  15. Universal dynamics of a degenerate unitary Bose gas

    NASA Astrophysics Data System (ADS)

    Makotyn, P.; Klauss, C. E.; Goldberger, D. L.; Cornell, E. A.; Jin, D. S.

    2014-02-01

    From neutron stars to high-temperature superconductors, strongly interacting many-body systems at or near quantum degeneracy are a rich source of intriguing phenomena. The microscopic structure of the first-discovered quantum fluid, superfluid liquid helium, is difficult to access owing to limited experimental probes. Although an ultracold atomic Bose gas with tunable interactions (characterized by its scattering length, a) had been proposed as an alternative strongly interacting Bose system, experimental progress has been limited by its short lifetime. Here we present time-resolved measurements of the momentum distribution of a Bose-condensed gas that is suddenly jumped to unitarity, where . Contrary to expectation, we observe that the gas lives long enough to permit the momentum to evolve to a quasi-steady-state distribution, consistent with universality, while remaining degenerate. Investigations of the time evolution of this unitary Bose gas may lead to a deeper understanding of quantum many-body physics.

  16. Quantum correlation in degenerate optical parametric oscillators with mutual injections

    E-print Network

    Takata, Kenta

    2015-01-01

    We theoretically and numerically study the quantum dynamics of two degenerate optical parametric oscillators with mutual injections. The cavity mode in the optical coupling path between the two oscillator facets is explicitly considered. Stochastic equations for the oscillators and mutual injection path based on the positive $P$ representation are derived. The system of two gradually pumped oscillators with out-of-phase mutual injections are simulated, and their quantum states are investigated. When the incoherent loss of the oscillators other than the mutual injections is small, the squeezed quadratic amplitudes $\\hat{p}$ in the oscillators are positively correlated near the oscillation threshold. It indicates finite quantum correlation, and the entanglement between the intracavity subharmonic fields. When with a small loss of the injection path, each oscillator around the phase transition point forms macroscopic superposition for a small pump noise. It suggests that the low-loss injection path works as a sq...

  17. Wave functions of hot excitons in semiconductors with degenerate bands

    SciTech Connect

    Efanov, A. V. [Russian Academy of Sciences, Institute of Semiconductor Physics, Siberian Branch (Russian Federation)], E-mail: efanov@isp.nsc.ru

    2008-06-15

    Hot excitons in direct-gap cubic semiconductors with a degenerate valence band are considered. Corrections to the model of independent excitonic branches in terms of the small parameter {Dirac_h}/Ka{sub B}, where K is the exciton momentum and a{sub B} is the Bohr radius, are determined. The corrections take into account the internal motion of particles in the exciton. It is shown that the internal motion mixes the states of light and heavy holes in the exciton wave function. As a result, the processes of forward scattering of excitons with transitions between different excitonic branches become allowed. The consideration is concerned with the region of kinetic energies no higher than the spin-orbit splitting in the valence band. The dispersion relation for holes is described in the spherical Kohn-Luttinger model (the 4 x 4 matrix)

  18. Bietti's tapetoretinal degeneration with marginal corneal dystrophy crystalline retinopathy.

    PubMed Central

    Welch, R B

    1977-01-01

    In 1937 Bietti reported a tapetoretinal degeneration with associated corneal deposits at the limbus. The hallmark of the disease was the crystalline characteristics of the retinal spots as well as those at the corneal limbus. Bagolini and Ioli-Spade in 1968 presented a 30 year follow-up on Bietti's cases and presented six additional cases. The present report delas with this entity in Orientals, a Chinese woman and a Japanese man. Corneal and conjunctival biopsy from the female patient revelaed a lipid deposition in both fibroblasts and epithelium. The term "crystalline retinopathy" has been added to the description of this entity since it defines the most characteristic feature of the syndrome. Images FIGURE 7 A FIGURE 7 B FIGURE 1 A FIGURE 1 B FIGURE 1 C FIGURE 2 A FIGURE 2 B FIGURE 2 C FIGURE 3 FIGURE 4 A FIGURE 4 B FIGURE 5 FIGURE 6 A FIGURE 6 B FIGURE 6 C FIGURE 8 PMID:306693

  19. Genetic factors of age-related macular degeneration

    PubMed Central

    Tuo, Jingsheng; Bojanowski, Christine M.; Chan, Chi-Chao

    2007-01-01

    Age-related macular degeneration (AMD) is a leading cause of blindness in the United States and developed countries. Although the etiology and pathogenesis of AMD remain unknown, a complex interaction of genetic and environmental factors is thought to exist. The incidence and progression of all of the features of AMD are known to increase significantly with age. The tendency for familial aggregation and the findings of gene variation association studies implicate a significant genetic component in the development of AMD. This review summarizes in detail the AMD-related genes identified by studies on genetically engineered and spontaneously gene-mutated (naturally mutated) animals, AMD chromosomal loci identified by linkage studies, AMD-related genes identified through studies of monogenic degenerative retinal diseases, and AMD-related gene variation identified by association studies. PMID:15094132

  20. Protective Effect of Ligustrazine on Lumbar Intervertebral Disc Degeneration of Rats Induced by Prolonged Upright Posture

    PubMed Central

    Liang, Qian-Qian; Ding, Dao-Fang; Xi, Zhi-Jie; Chen, Yan; Li, Chen-Guang; Liu, Shu-Fen; Lu, Sheng; Zhao, Yong-Jian; Shi, Qi; Wang, Yong-Jun

    2014-01-01

    Most chronic low back pain is the result of degeneration of the lumbar intervertebral disc. Ligustrazine, an alkaloid from Chuanxiong, reportedly is able to relieve pain, suppress inflammation, and treat osteoarthritis and it has the protective effect on cartilage and chondrocytes. Therefore, we asked whether ligustrazine could reduce intervertebral disc degeneration. To determine the effect of ligustrazine on disc degeneration, we applied a rat model. The intervertebral disc degeneration of the rats was induced by prolonged upright posture. We found that pretreatment with ligustrazine for 1 month recovered the structural distortion of the degenerative disc; inhibited the expression of type X collagen, matrix metalloproteinase (MMP)-13, and MMP3; upregulated type II collagen; and decreased IL-1?, cyclooxygenase (COX)-2, and inducible nitric oxide synthase (iNOS) expression. In conclusion, ligustrazine is a promising agent for treating lumbar intervertebral disc degeneration disease. PMID:24872832

  1. Degeneration of Brainstem Respiratory Neurons in Dementia with Lewy Bodies

    PubMed Central

    Presti, Michael F.; Schmeichel, Ann M.; Low, Phillip A.; Parisi, Joseph E.; Benarroch, Eduardo E.

    2014-01-01

    Background: Respiratory dysfunction, including sleep disordered breathing, is characteristic of multiple system atrophy (MSA) and may reflect degeneration of brainstem respiratory nuclei involved in respiratory rhythmogenesis and chemosensitivity, including the pre-Bötzinger complex (preBötC), nucleus raphe pallidus (RPa), and nucleus raphe obscurus (ROb). However, impaired ventilatory responses to hypercapnia have also been reported in dementia with Lewy bodies (DLB), suggesting that these nuclei may also be affected in DLB. Objectives: To determine whether there is involvement of the preBötC, RPa, and ROb in DLB. Design: We applied stereological methods to analyze sections immunostained for neurokinin-1 receptor and tryptophan hydroxylase in neuropathologically confirmed cases of DLB, MSA, and controls. Results: Reduction of neuronal density occurred in all three nuclei in DLB, as well as in MSA. The magnitude of neuronal depletion in ROb was similar in DLB and MSA (49% versus 56% respectively, compared to controls, P < 0.05), but neuronal loss in the preBötC and RPa was less severe in DLB than in MSA (40% loss in preBötC of DLB, P < 0.05 and 68% loss in MSA, P < 0.0001, compared to controls; 46% loss in RPa of DLB, P < 0.05 and 73% loss in MSA P < 0.0001, compared to controls). Conclusions: Medullary respiratory nuclei are affected in dementia with Lewy bodies but less severely than in multiple system atrophy. This may help explain differences in the frequency of sleep disordered breathing in these two disorders. Citation: Presti MF; Schmeichel MA; Low PA; Parisi JE; Benarroch EE. Degeneration of brainstem respiratory neurons in dementia with Lewy bodies. SLEEP 2014;37(2):373-378. PMID:24501436

  2. Helicoidal peripapillary chorioretinal degeneration: electrophysiology and psychophysics in 17 patients

    PubMed Central

    Eysteinsson, T.; Jonasson, F.; Jonsson, V.; Bird, A.

    1998-01-01

    AIMS—To characterise retinal function using electrophysiological and psychophysical tests in 17 patients with helicoidal peripapillary chorioretinal degeneration.?METHODS—The electroretinogram (ERG) was recorded using gold foil corneal electrodes. The electro-oculogram (EOG) was recorded using a standard protocol. Dark adaptometry was recorded with an SST-1 dark adaptometer and colour vision assessed with Ishihara plates and Farnsworth D-15.?RESULTS—All subjects had a recordable ERG. The amplitudes and implicit times of the a- and b-waves were within normal limits at all luminances in five subjects (age 21-70 years, mean 40 years). The ERG of six (age 26-55 years, mean 40.7 years) had subnormal amplitudes at all luminances, but normal implicit times, and six (age 38-81 years, mean 60.7 years) had abnormal ERGs with marked reduction of a- and b-waves, and delayed implicit times of the b-wave. The implicit times of the a-wave were normal in all subjects. A reduction in the b/a wave ratios was not found, nor was there selective loss of scotopic, mixed rod/cone, or cone responses. The light/dark ratio of the EOG was subnormal (150-185%) or abnormal (below 150%) in all but three subjects. Two patients with normal EOG showed normal ERGs in both eyes, but one had subnormal ERGs in both eyes. The scotopic sensitivity was normal in all subjects and dark adaptation showed a normal time course. Colour vision was normal in all patients.?CONCLUSION—The results suggest that in most cases the function of the retinal pigment epithelium is affected by this disease before any changes in the function of the sensory retina are detectable by our methods, and that retinal dysfunction is focal rather than diffuse.?? Keywords: chorioretinal degeneration; electroretinogram; dark adaptation; colour vision PMID:9602625

  3. Burn injury induces skeletal muscle degeneration, inflammatory host response, and oxidative stress in wistar rats.

    PubMed

    da Silva, Nathalia Trasmonte; Quintana, Hananiah Tardivo; Bortolin, Jeferson André; Ribeiro, Daniel Araki; de Oliveira, Flavia

    2015-01-01

    Burn injuries (BIs) result in both local and systemic responses distant from the site of thermal injury, such as skeletal muscle. The purpose of this study was to investigate the expression of cyclooxygenase-2 (COX-2) and hydroxy-2'-deoxyguanosine (8-OHdG) as a result of inflammation and reactive oxygen species production, respectively. A total of 16 male rats were distributed into two groups: control (C) and submitted to BI. The medial part of gastrocnemius muscle formed the specimens, which were stained with hematoxylin and eosin and were evaluated. COX-2 and 8-OHdG expressions were assessed by immunohistochemistry, and cell profile area and density of muscle fibers (number of fibers per square millimeter) were evaluated by morphometric methods. The results revealed inflammatory infiltrate associated with COX-2 immunoexpression in BI-gastrocnemius muscle. Furthermore, a substantial decrease in the muscle cell profile area of BI group was noticed when compared with the control group, whereas the density of muscle fibers was higher in the BI group. 8-OHdG expression in numerous skeletal muscle nuclei was detected in the BI group. In conclusion, the BI group is able to induce skeletal muscle degeneration as a result of systemic host response closely related to reactive oxygen species production and inflammatory process. PMID:25933049

  4. Recent Patents on Emerging Therapeutics for the Treatment of Glaucoma, Age Related Macular Degeneration and Uveitis

    PubMed Central

    Vadlapudi, Aswani Dutt; Patel, Ashaben; Cholkar, Kishore; Mitra, Ashim K.

    2014-01-01

    Advancements in the field and rising interest among pharmaceutical researchers have led to the development of new molecules with enhanced therapeutic activity. Design of new drugs which can target a particular pathway and/or explore novel targets is of immense interest to ocular pharmacologists worldwide. Delivery of suitable pharmacologically active agents at proper dose (within the therapeutic window) to the target tissues without any toxicity to the healthy ocular tissues still remain an elusive task. Moreover, the presence of static and dynamic barriers to drug absorption including the corneal epithelium (lipophilic), corneal and scleral stroma (hydrophilic), conjunctival lymphatics, choroidal vasculature and the blood-ocular barriers also pose a significant challenge for achieving therapeutic drug concentrations at the target site. Although many agents are currently available, new compounds are being introduced for treating various ocular diseases. Deeper understanding of the etiology and complex mechanisms associated with the disease condition would aid in the development of potential therapeutic candidates. Novel small molecules as well as complex biotechnology derived macromolecules with superior efficacy, safety and tolerability are being developed. Therefore, this review article provides an overview of existing drugs, treatment options, advances in emerging therapeutics and related recent patents for the treatment of ocular disorders such as glaucoma, age related macular degeneration (AMD) and uveitis. PMID:25414810

  5. A plant Y chromosome-STS marker encoding a degenerate retrotransposon.

    PubMed

    Obara, Mari; Matsunaga, Sachihiro; Nakao, Shunsuke; Kawano, Shigeyuki

    2002-12-01

    The dioecious plant Silene latifolia has both X and Y sex chromosomes. Male-specific random amplified polymorphic DNA (RAPD) fragments were analyzed to identify Y-chromosome-linked sequences. One of the RAPD fragments, MS4, was converted into a more reliable and reproducible sequence-tagged site (STS) marker. A set of MS4 STS primers was used to amplify two genomic DNA fragments (MS4a and MS4b) from a male plant and one (MS4a) from a female plant, which indicates that MS4b is located on the Y chromosome. Sequence analysis revealed that MS4a encoded a gag protein of a Ty3-gypsy-like retrotransposon. A 147-bp region from the middle of MS4a was deleted in MS4b. The MS4b sequence was not detected in the most closely related dioecious species, S. dioica. This suggests that a retrotransposon with the MS4b sequence has degenerated recently on the Y chromosome. PMID:12589074

  6. Regulation of age-related macular degeneration-like pathology by complement factor H.

    PubMed

    Toomey, Christopher B; Kelly, Una; Saban, Daniel R; Bowes Rickman, Catherine

    2015-06-01

    Complement factor H (CFH) is a major susceptibility gene for age-related macular degeneration (AMD); however, its impact on AMD pathobiology is unresolved. Here, the role of CFH in the development of AMD pathology in vivo was interrogated by analyzing aged Cfh(+/-) and Cfh(-/-) mice fed a high-fat, cholesterol-enriched diet. Strikingly, decreased levels of CFH led to increased sub-retinal pigmented epithelium (sub-RPE) deposit formation, specifically basal laminar deposits, following high-fat diet. Mechanistically, our data show that deposits are due to CFH competition for lipoprotein binding sites in Bruch's membrane. Interestingly and despite sub-RPE deposit formation occurring in both Cfh(+/-) and Cfh(-/-) mice, RPE damage accompanied by loss of vision occurred only in old Cfh(+/-) mice. We demonstrate that such pathology is a function of excess complement activation in Cfh(+/-) mice versus complement deficiency in Cfh(-/-) animals. Due to the CFH-dependent increase in sub-RPE deposit height, we interrogated the potential of CFH as a previously unidentified regulator of Bruch's membrane lipoprotein binding and show, using human Bruch's membrane explants, that CFH removes endogenous human lipoproteins in aged donors. Thus, advanced age, high-fat diet, and decreased CFH induce sub-RPE deposit formation leading to complement activation, which contributes to RPE damage and visual function impairment. This new understanding of the complicated interactions of CFH in AMD-like pathology provides an improved foundation for the development of targeted therapies for AMD. PMID:25991857

  7. Value siting

    SciTech Connect

    Ferrar, T.A. [PRA Management Consultants, Atlanta, GA (United States); Howes, J.A. [Redland Energy Group, Arlington, VA (United States)

    1995-02-01

    Finding an appropriate site is becoming an increasing challenge in building new power projects. One of the first orders of business in project development is identifying a site that offers the maximum spread between the cost of fuel and net power price. The collection of sites that exhibit an adequate spread - presenting a first-order, acceptable economic expectation - must now be subjected to an ever increasing number of political, societal, technical, and economic exclusion screens. The barriers can include cooling water constraints, community resistance, visual incompatibility, archaeological concerns and endangered species preservation issues. Most power siting difficulties can be substantially mitigated by gaining access to developed, but under-used sites, whose current owners are bound by circumstances - political or financial - that prevent them from using such locations. There are two such categories of sites: Utilities that have sites on which depreciated power production assets rest; and, The federal government, with numerous sites throughout the country, particularly military bases subject to closure under the Base Realignment and Closure (BRAC) proceedings. It is in the interests of developers, as well as consumers, investors and taxpayers, ti undertake a thorough examination of these overlooked pearls of opportunities and develop their potential.

  8. CX3CL1 (Fractalkine) Protein Expression in Normal and Degenerating Mouse Retina: In Vivo Studies

    PubMed Central

    Zieger, Marina; Ahnelt, Peter K.; Uhrin, Pavel

    2014-01-01

    We aimed to investigate fractalkine (CX3CL1) protein expression in wild type (wt) retina and its alterations during retinal degeneration in mouse model (rd10) of retinitis pigmentosa. Forms of retinal protein CX3CL1, total protein and mRNA levels of CX3CL1 were analyzed at postnatal days (P) 5, 10, 14, 22, 30, 45, and 60 by Western blotting and real-time PCR. Cellular sources of CX3CL1 were investigated by in situ hybridization histochemistry (ISH) and using transgenic (CX3CL1cherry) mice. The immunoblots revealed that in both, wt and rd10 retinas, a membrane integrated ?100 kDa CX3CL1 form and a cleaved ?85 kDa CX3CL1 form were present at P5. At P10, accumulation of another presumably intra-neuronal ?95 kDa form and a decrease in the ?85-kDa form were observed. From P14, a ?95 kDa form became principal in wt retina, while in rd10 retinas a soluble ?85 kDa form increased at P45 and P60. In comparison, retinas of rd10 mice had significantly lower levels of total CX3CL1 protein (from P10 onwards) and lower CX3CL1 mRNA levels (from P14), even before the onset of primary rod degeneration. ISH and mCherry reporter fluorescence showed neurons in the inner retina layers as principal sites of CX3CL1 synthesis both in wt and rd10 retinas. In conclusion, our results demonstrate that CX3CL1 has a distinctive course of expression and functional regulation in rd10 retina starting at P10. The biological activity of CX3CL1 is regulated by conversion of a membrane integrated to a soluble form during neurogenesis and in response to pathologic changes in the adult retinal milieu. Viable mature neurons in the inner retina likely exhibit a dynamic intracellular storage depot of CX3CL1. PMID:25191897

  9. Influence of IL-20 on lumbar disc degeneration:An experimental study

    PubMed Central

    Yang, Tianjing; Xu, Huaqing

    2015-01-01

    Objective: To determine the influence of IL-20 on the development of lumbar degeneration. Methods: The study design was prospective and carried out in Tianjin Fourth center Hospital, Tianjin, China between Jan 2012 and Jan 2014. Sixty-nine patients with degenerative disc disease treated surgically were included in experimental group, and fifteen patients with normal discs were included in control group. The evaluation of disc degeneration was performed using T2-weighted sagittal MRI according to the Modified Pfirrmann Grading System. After surgery, the intervertebral disc in both groups was collected and the content of proteoglycan and IL-20 were measured, the correlation between the content of IL-20, proteoglycan and the degeneration grade of lumbar disc was analyzed. Results: Compared to control group, the content of proteoglycan in experimental group is significantly lower (P=0.000), but IL-20 is significantly higher (P=0.001). In addition, with the advance of intervertebral disc degeneration, the content of IL-20 increase, while proteoglycan decrease gradually. There is significant correlation between the content of proteoglycan (p=0.001), IL-20 (p=0.002) and the degeneration grade of lumbar disc. Conclusion: In patients with degenerative disc disease, the content of IL-20 and proteoglycan has significant correlation with degeneration grade of lumbar disc, and IL-20 may promote the degeneration of lumbar disc by affecting the synthesis of proteoglycan. PMID:25878634

  10. Evaluation of the Effect of Mega MSM on Improving Joint Function in Populations Experiencing Joint Degeneration

    PubMed Central

    Xu, Gang; Zhou, Tian; Gu, Yaqin; Wang, Qinping; Shariff, Mina; Gu, Pingping; Nguyen, Tuong; Shi, Rong; Rao, Jianyu

    2015-01-01

    Joint degeneration has become a commonplace problem in aging populations. The main clinical manifestations include joint pain, joint stiffness and joint swelling with functional disorder. Mega MSM is a nutritional supplement that may provide potential relief for joint problems associated with joint degeneration. The current experiment performed was a 12-week, randomized, double-blind, controlled study conducted on populations in China experiencing joint degeneration. The objective of the study was to determine whether the daily use of Mega MSM capsules could improve joint function, relieve symptoms of joint degeneration and improve the quality of life in aging populations. A total of 100 male and female participants over 50 years old who had at least one of the related symptoms of joint degeneration (joint pain, joint stiffness, joint swelling, difficulty walking, difficulty getting up from bed and difficulty going down stairs) were recruited and their symptoms of joint degeneration before and after the intervention were recorded. In this study, Mega MSM shows positive effects in improving joint function, relieving symptoms associated with joint degeneration and improving the quality of life in aging populations. PMID:26199577

  11. Ethanol-related Increases in Degenerating Bodies in the Purkinje Neuron Dendrites of Aging Rats

    PubMed Central

    Dlugos, Cynthia A.

    2008-01-01

    Chronic ethanol consumption in aging rats results in regression of Purkinje neuron (PN) dendritic arbors (Pentney, 1995), loss of synapses (Dlugos and Pentney, 1997), dilation of the smooth endoplasmic reticulum (SER), and the formation of degenerating bodies within PN dendrites (Dlugos 2006 a, b). Dilation of the SER and the formation of degenerating bodies may be a predictor of dendritic regression. Ethanol-induced effects on mitochondria may be involved as mitochondria cooperate with the SER to maintain calcium homeostasis. The purpose of this study was to determine whether degenerating body number and mitochondrial density and structure are altered by chronic ethanol treatment in PN dendrites. Male, Fischer 344 rats, 12 months of age, were fed an ethanol or pair-fed liquid diet, or rat chow for a period of 10, 20, or 40 weeks (15 rats / treatment; 45rats /treatment duration). Ethanol-fed rats received 35% of their calories as ethanol. At the end of treatment, all animals were euthanized, perfused, and tissue prepared for electron microscopy. The densities of degenerating bodies and mitochondria, mitochondrial areas, and the distance between the SER and the mitochondria were measured. Results showed that there was an ethanol-related increase in degenerating bodies compared to controls at 40 weeks. Ethanol-induced alterations to mitochondria were absent. Correlation of the present results with those of previous studies suggest that degenerating bodies may be formed from membrane re-absorption during dendritic regression or from degenerating SER whose function has been compromised by dilation. PMID:18559274

  12. Adipose-derived stem cells improve the viability of nucleus pulposus cells in degenerated intervertebral discs.

    PubMed

    Song, Keran; Gu, Tao; Shuang, Feng; Tang, Jiaguang; Ren, Dongfeng; Qin, Jiang; Hou, Shuxun

    2015-09-01

    Patients with degenerative disc disease (DDD) experience serious clinical symptoms, including chronic low back pain. A series of therapies have been developed to treat DDD, including physical therapy and surgical treatment. However, the therapeutic effect of such treatments has remained insufficient. Recently, stem cell?based therapy, in which stem cells are injected into the nucleus pulposus in degenerated intervertebral disc tissue, has appeared to be effective in the treatment of DDD. In the present study, the effect of adipose?derived stem cells on degenerated nucleus pulposus cells was investigated using a co?culture system to evaluate the biological activity of degenerated nucleus pulposus cells. Human degenerated nucleus pulposus tissue was obtained from surgical specimens and the adipose?derived stem cells were derived from adipose tissue. The degenerated nucleus pulposus cells were cultured in a mono?culture or in a co?culture with adipose?derived stem cells using 0.4?µm Transwell inserts. The results indicated that adipose?derived stem cells were able to stimulate matrix synthesis and the cell proliferation of degenerated nucleus pulposus cells, promoting the restoration of nucleus pulposus cells in the degenerated intervertebral disc. PMID:26059030

  13. Association between apparent diffusion coefficient and intervertebral disc degeneration in patients with ankylosing spondylitis

    PubMed Central

    Resorlu, Mustafa; Gokmen, Ferhat; Resorlu, Hatice; Adam, Gurhan; Akbal, Ayla; Cevizci, Sibel; Sariyildirim, Abdullah; Savas, Yilmaz; Guven, Mustafa; Aras, Adem Bozkurt

    2015-01-01

    Purpose: To assess the relation between ankylosing spondylitis (AS) and degenerative disc disease emerging in association with various intrinsic and extrinsic factors and to evaluate the correlation between degree of degeneration in intervertebral discs and apparent diffusion coefficient (ADC) values. Methods: Thirty-five patients with AS and a control group of 35 patients were included in the study. Three hundred fifty intervertebral discs were assessed in terms of degeneration by analyzing signal intensities and morphologies on T2 weighted series of a 1.5 Tesla magnetic resonance scanner. ADC values were determined in diffusion weighted images (DWI) using a “b value of 500 s/mm2”. Patients in the AS and control groups were compared in terms of intervertebral disc degeneration, and association between degree of degeneration and ADC values was analyzed. Results: The mean of total degeneration degrees for five lumbar intervertebral discs was significantly higher in the patients with AS compared to the control group (16.77±4.67 vs 13.00±4.08, respectively; P=0.001). When intervertebral discs were analyzed separately, disc degeneration was again significantly higher in patients with AS compared to the control group, with the exception of L5-S1. Age, cholesterol level, triglyceride level, duration of disease and BASFI index were significantly associated with degree of degeneration in patients with AS. A negative correlation was determined between disc degeneration and ADC value. Conclusion: AS is a risk factor for degenerative disc disease due to its systemic effects, the fact it leads to posture impairment and its inflammatory effects on the vertebrae. A decrease in ADC values is observed as degeneration worsens in degenerative disc disease. PMID:25785119

  14. Anterograde Degeneration along the Visual Pathway after Optic Nerve Injury

    PubMed Central

    Graham, Stuart L.; Klistorner, Alexander

    2012-01-01

    Purpose To investigate anterograde degenerative changes along the visual pathway in a rat model of optic nerve axotomy. Methods Optic nerve transection was performed in adult Sprague-Dawley rats. Animals were sacrificed at regular time intervals and tissues harvested. Immunoblotting followed by densitometric analysis was used to determine the phosphorylation profile of Akt in the dorsal lateral geniculate nucleus (dLGN) and the primary visual cortex (V1). The neuronal cell size and cell density were measured in the dLGN and the V1 using Nissl staining. The prevalence of apoptosis was characterized by terminal deoxynucleotidyl-transferase-mediated biotin-dUTP nick end labelling (TUNEL) histochemistry. Caspase-3 antibodies were also used to identify apoptotic cells. Neurons and astrocytes were detected using NeuN and glial fibrillary acidic protein (GFAP), respectively. Results An early and sustained loss of Akt phosphorylation was observed after optic nerve transection in both dLGN and V1. At week one, a decrease in the neuronal cell size (50.5±4.9 vs 60.3±5.0 µm2, P?=?0.042) and an increase of TUNEL positive cells (7.9±0.6 vs 1.4±0.5 ×102 cells/mm2, P<0.001) were evident in the dLGN but not in V1. A significant decline in neuronal cell number (14.5±0.1 vs 17.4±1.3 ×102 cells/mm2, P?=?0.048), cell size (42.5±4.3 vs 62.1±4.7 µm2, P?=?0.001) and an increase in apoptotic cells (5.6±0.5 vs 2.0±0.4 ×102 cells/mm2, P<0.001) appeared in V1 initially at one month post-transection. The changes in the visual pathway continued through two months. Both neuronal cells and GFAP-positive glial cells were affected in this anterograde degeneration along the visual pathway. Conclusions Anterograde degeneration along the visual pathway takes place in target relay (LGN) and visual cortex following the optic nerve injury. Apoptosis was observed in both neural and adjacent glial cells. Reduction of Akt phosphorylation preceded cellular and apoptotic changes. PMID:23300590

  15. Age-related macular degeneration: beyond anti-angiogenesis.

    PubMed

    Kent, David L

    2014-01-01

    Recently, anti-vascular endothelial growth factor therapies for neovascular age-related macular degeneration have been developed. These agents, originally developed for their anti-angiogenic mechanism of action, probably also work through an anti-permeability effect in preventing or reducing the amount of leakage from submacular neovascular tissue. Other treatment modalities include laser photocoagulation, photodynamic therapy with verteporfin, and submacular surgery. In reality, these latter treatments can be similarly categorized as anti-angiogenic because their sole aim is destroying or removing choroidal neovascularization (CNV). At the cellular level, CNV resembles stereotypical tissue repair that consists of several matricellular components in addition to neovascularization. In the retina, the clinical term CNV is a misnomer since the term may more appropriately be referred to as aberrant submacular repair. Furthermore, CNV raises a therapeutic conundrum: To complete or correct any reparative process in the body, angiogenesis becomes an essential component. Anti-angiogenic therapy, in all its guises, arrests repair and causes the hypoxic environment to persist, thus fueling pro-angiogenesis and further development of CNV as a component of aberrant repair. However, we realize that anti-vascular endothelial growth factor therapy preserves vision in patients with age-related macular degeneration, albeit temporarily and therefore, repeated treatment is needed. More importantly, however, anti-angiogenic therapy demonstrates that we can at the very least tolerate neovascular tissue beneath the macula and preserve vision in contrast to our historical approach of total vascular destruction. In this clinical scenario, it may be possible to look beyond anti-angiogenesis if our goal is facilitating submacular repair without destroying the neurosensory retina. Thus, in this situation of neovascular tolerance, it may be timely to consider treatments that facilitate vascular maturation, rather than its arrest or destruction. This would neutralize hypoxia, thus removing the stimulus that drives neovascularization and in turn the need for repeated lifelong intravitreal therapy. A pro-angiogenic approach would eliminate neovascular leakage and ultimately complete repair and preserve the neurosensory retina. PMID:24426775

  16. Automatic age-related macular degeneration detection and staging

    NASA Astrophysics Data System (ADS)

    van Grinsven, Mark J. J. P.; Lechanteur, Yara T. E.; van de Ven, Johannes P. H.; van Ginneken, Bram; Theelen, Thomas; Sánchez, Clara I.

    2013-03-01

    Age-related macular degeneration (AMD) is a degenerative disorder of the central part of the retina, which mainly affects older people and leads to permanent loss of vision in advanced stages of the disease. AMD grading of non-advanced AMD patients allows risk assessment for the development of advanced AMD and enables timely treatment of patients, to prevent vision loss. AMD grading is currently performed manually on color fundus images, which is time consuming and expensive. In this paper, we propose a supervised classification method to distinguish patients at high risk to develop advanced AMD from low risk patients and provide an exact AMD stage determination. The method is based on the analysis of the number and size of drusen on color fundus images, as drusen are the early characteristics of AMD. An automatic drusen detection algorithm is used to detect all drusen. A weighted histogram of the detected drusen is constructed to summarize the drusen extension and size and fed into a random forest classifier in order to separate low risk from high risk patients and to allow exact AMD stage determination. Experiments showed that the proposed method achieved similar performance as human observers in distinguishing low risk from high risk AMD patients, obtaining areas under the Receiver Operating Characteristic curve of 0.929 and 0.934. A weighted kappa agreement of 0.641 and 0.622 versus two observers were obtained for AMD stage evaluation. Our method allows for quick and reliable AMD staging at low costs.

  17. SINGLE-DEGENERATE TYPE Ia SUPERNOVAE WITHOUT HYDROGEN CONTAMINATION

    SciTech Connect

    Justham, Stephen, E-mail: sjustham@pku.edu.cn [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing (China)

    2011-04-01

    The lack of hydrogen in spectra of type Ia supernovae (SNe Ia) is often seen as troublesome for single-degenerate (SD) progenitor models. We argue that, since continued accretion of angular momentum can prevent explosion of the white dwarf, it may be natural for the donor stars in SD progenitors of SNe Ia to exhaust their envelopes and shrink rapidly before the explosion. This outcome seems most likely for SD SN Ia progenitors where mass transfer begins from a giant donor star and might extend to other SD systems. Not only is the amount of hydrogen left in such a system below the current detection limit, but the donor star is typically orders of magnitude smaller than its Roche lobe by the point when an SD SN Ia occurs, in which case attempts to observe collisions between SN shocks and giant donor stars seem unlikely to succeed. We consider the constraints on this model from the circumstellar structures seen in spectra of SN 2006X and suggest a novel explanation for the origin of this material.

  18. Therapeutic Modalities of Exudative Age-related Macular Degeneration

    PubMed Central

    Mavija, Milka; Alimanovic, Emina; Jaksic, Vesna; Kasumovic, Sanja Sefic; Cekic, Sonja; Stamenkovic, Miroslav

    2014-01-01

    Introduction: Age-related macular degeneration (AMD) is a leading cause of irreversible serious vision damage in persons over 50 years of age. In treating AMD many medicaments are applied such as inhibitors of vascular endothelial growth factor (VEGF), have been very carefully included over the last few years after a series of study research. Aims: To analyze the past methods of treatment, discuss emerging therapies which could advance the treatment of exudative AMD. The past anti-VEGF therapies require frequent repetitions of administration, with uncertain visual acuity recovery, as not all patients react to anti-VEGF therapy. Consequently, there is a need to find out additional therapies which could improve the treatment of exudative AMD. The real aim in the treating of AMD is to prevent CNV development. Methods: A survey of the current clinical research and results in the field of the present and future treatments of exudative AMD. Results: There are many areas of research into new methods of the exudative AMD treatment. Conclusion: The future therapies for exudative AMD treatment have a potential not only to reduce the frequency of administration and follow-up visits, but also to improve effects of treatment by targeting additional ways of CNV development, increasing the aptitude of target binding and extending durability of treatment. PMID:25568535

  19. Degenerate Quasicrystal of Hard Triangular Bipyramids Stabilized by Entropic Forces

    NASA Astrophysics Data System (ADS)

    Haji-Akbari, Amir; Engel, Michael; Glotzer, Sharon

    2012-02-01

    The assembly of hard polyhedra into novel ordered structures has recently received much attention. Here we focus on triangular bipyramids (TBPs)- i.e. dimers of hard tetrahedra- which pack densely in a simple triclinic crystal with two particles per unit cell [1]. This packing is referred to as the TBP crystal. We show that hard TBPs do not form this densest packing in simulation. Instead, they assemble into a different, far more complicated structure, a dodecagonal quasicrystal, which, in the level of monomers, is identical to the quasicrystal recently discovered in the hard tetrahedron system [2], but the way that tetrahedra pair into TBPs in the nearest neighbor network is random, making it the first degenerate quasicrystal reported in the literature [3]. This notion of degeneracy is in the level of decorating individual tiles and is different from the degeneracy of a quasiperiodic random tiling arising from phason flips [4]. The (3.4.3^2.4) approximant of the quasicrystal is shown to be more stable than the TBP crystal at densities below 79.7%.[4pt] [1] Chen ER, Engel M, Sharon SC, Disc. Comp. Geom. 44:253 (2010).[0pt] [2] Haji-Akbari A, Engel M, et al. Nature 462:773 (2009).[0pt] [3] Haji-Akbari A, Engel M, Glotzer SC, arXiv:1106.5561 [PRL, in press].[0pt] [4] Elser V, PRL 54: 1730 (1985)

  20. Age-Related Macular Degeneration: A Scientometric Analysis.

    PubMed

    Ramin, Shahrokh; Soheilian, Masoud; Habibi, Gholamreza; Ghazavi, Roghayeh; Gharebaghi, Reza; Heidary, Fatemeh

    2015-01-01

    Age-related macular degeneration (ARMD) is a major cause of central blindness among working aged adults across the world. Systematic research planning on any subject, including ARMD is in need of solid data regarding previous efforts in this field and to identify the gaps in the research. This study aimed to elucidate the most important trends, directions, and gap in this subject. The data extracted from the Institute for Scientific Information were used to perform a bibliometric analysis of the scientific productions (1993-2013) about ARMD. Specific parameters related to ARMD were analyzed to obtain a view of the topic's structure, history, and document relationships. Additionally, the trends and authors in the most influential publications were analyzed. The number of articles in this field was found constantly increasing. Most highly cited articles addressed genetic epidemiology and clinical research topics in this field. During the past 3 years, there has been a trend toward biomarker research. Through performing the first scientometric survey on ARMD research, we analyzed the characteristics of papers and the trends in scientific production. We also identified some of the critical gaps in the current research efforts that would help in large-scale research strategic planning. PMID:26060829

  1. White matter degeneration in schizophrenia: a comparative diffusion tensor analysis

    NASA Astrophysics Data System (ADS)

    Ingalhalikar, Madhura A.; Andreasen, Nancy C.; Kim, Jinsuh; Alexander, Andrew L.; Magnotta, Vincent A.

    2010-03-01

    Schizophrenia is a serious and disabling mental disorder. Diffusion tensor imaging (DTI) studies performed on schizophrenia have demonstrated white matter degeneration either due to loss of myelination or deterioration of fiber tracts although the areas where the changes occur are variable across studies. Most of the population based studies analyze the changes in schizophrenia using scalar indices computed from the diffusion tensor such as fractional anisotropy (FA) and relative anisotropy (RA). The scalar measures may not capture the complete information from the diffusion tensor. In this paper we have applied the RADTI method on a group of 9 controls and 9 patients with schizophrenia. The RADTI method converts the tensors to log-Euclidean space where a linear regression model is applied and hypothesis testing is performed between the control and patient groups. Results show that there is a significant difference in the anisotropy between patients and controls especially in the parts of forceps minor, superior corona radiata, anterior limb of internal capsule and genu of corpus callosum. To check if the tensor analysis gives a better idea of the changes in anisotropy, we compared the results with voxelwise FA analysis as well as voxelwise geodesic anisotropy (GA) analysis.

  2. Selenium induces cholinergic motor neuron degeneration in Caenorhabditis elegans

    PubMed Central

    Estevez, Annette O.; Mueller, Catherine L.; Morgan, Kathleen L.; Szewczyk, Nathaniel J.; Teece, Luke; Miranda-Vizuete, Antonio; Estevez, Miguel

    2012-01-01

    Selenium is an essential micronutrient required for cellular antioxidant systems, yet at higher doses it induces oxidative stress. Additionally, in vertebrates environmental exposures to toxic levels of selenium can cause paralysis and death. Here we show that selenium-induced oxidative stress leads to decreased cholinergic signaling and degeneration of cholinergic neurons required for movement and egg-laying in Caenorhabditis elegans. Exposure to high levels of selenium leads to proteolysis of a soluble muscle protein through mechanisms suppressible by two pharmacological agents, levamisole and aldicarb which enhance cholinergic signaling in muscle. In addition, animals with reduction-of-function mutations in genes encoding post-synaptic levamisole-sensitive acetylcholine receptor subunits or the vesicular acetylcholine transporter developed impaired forward movement faster during selenium-exposure than normal animals, again confirming that selenium reduces cholinergic signaling. Finally, the antioxidant reduced glutathione, inhibits selenium-induced reductions in egg-laying through a cellular protective mechanism dependent on the C. elegans glutaredoxin, GLRX-21. These studies provide evidence that the environmental toxicant selenium induces neurodegeneration of cholinergic neurons through depletion of glutathione, a mechanism linked to the neuropathology of Alzheimer’s disease, amyotrophic lateral sclerosis, and Parkinson’s disease. PMID:22560997

  3. Analytical study of two-dimensional degenerate metamaterial antennas

    NASA Astrophysics Data System (ADS)

    Sakoda, Kazuaki; Zhou, Haifeng

    2011-07-01

    Dispersion curves of metamaterial steerable antennas composed of two-dimensional arrays of metallic unit structures with the C4v and C6v symmetries are calculated both qualitatively by the tight-binding approximation and quantitatively by the finite-difference time-domain method. Special attention is given to the case of eigenmodes of the E symmetry of the C4v point group and those of the E1 and E2 symmetries of the C6v point group, since they are doubly degenerate on the ? point of the Brillouin zone so that they naturally satisfy the steerability condition. We show that their dispersion curves have quadratic dependence on the wave vector in the vicinity of the ? point. To get a linear dispersion, which is advantageous for steerable antennas, we propose a method of controlled symmetry reduction. The present theory is an extension of our previous one [Opt. Express 18, 27371 (2010)] to two-dimensional systems, for which we can achieve the deterministic degeneracy due to symmetry and the controlled symmetry reduction becomes available. This design of metamaterial steerable antennas is advantageous in the optical frequency.

  4. Degenerate four-wave mixing in triply resonant Kerr cavities

    NASA Astrophysics Data System (ADS)

    Ramirez, David M.; Rodriguez, Alejandro W.; Hashemi, Hila; Joannopoulos, J. D.; Solja?i?, Marin; Johnson, Steven G.

    2011-03-01

    We demonstrate theoretical conditions for highly efficient degenerate four-wave mixing in triply resonant nonlinear (Kerr) cavities. We employ a general and accurate temporal coupled-mode analysis in which the interaction of light in arbitrary microcavities is expressed in terms of a set of coupling coefficients that we rigorously derive from the full Maxwell equations. Using the coupled-mode theory, we show that light consisting of an input signal of frequency ?0-?? can, in the presence of pump light at ?0, be converted with quantum-limited efficiency into an output shifted signal of frequency ?0+??, and we derive expressions for the critical input powers at which this occurs. We find the critical powers in the order of 10 mW, assuming very conservative cavity parameters (modal volumes ~10 cubic wavelengths and quality factors ~1000). The standard Manley-Rowe efficiency limits are obtained from the solution of the classical coupled-mode equations, although we also derive them from simple photon-counting “quantum” arguments. Finally, using a linear stability analysis, we demonstrate that maximal conversion efficiency can be retained even in the presence of self- and cross-phase modulation effects that generally act to disrupt the resonance condition.

  5. Late degeneration in rabbit tissues after irradiation by heavy ions

    NASA Technical Reports Server (NTRS)

    Lett, J. T.; Cox, A. B.; Keng, P. C.; Lee, A. C.; Su, C. M.; Bergtold, D. S.

    1980-01-01

    Results are presented for investigations of the late effects of heavy-ion irradiation on rabbit tissues which were undertaken to assess the hazards associated with the long-term exposure of humans to heavy ions in space during such activities as the construction of solar power stations or voyages to Mars. White rabbits approximately six weeks old were exposed to various doses of collimated beams of 400-MeV/n Ne ions, 570 MeV/n Ar ions and Co-60 gamma rays directed through both eyes, and the responses of the various tissues (hair follicles, skin, cornea, lens, retina, Harderian glands, bone and forebrain) were examined. Proliferating tissues are found to exhibit high damage levels in the early and late periods following irradiation, while terminally differentiating tissues repond to radiation most intensely in the late period, years after irradiation, with no intermediate recovery. The results obtained from rabbits are used to predict the occurrence of late tissue degeneration in the central nervous system, terminally differentiating systems and stem cells of humans one or more decades following exposure to radiation levels anticipated during long-duration space flights. The studies also indicate that tissues may be prematurely aged in the sense that tissue life spans may be shortened without the development of malignancies.

  6. Seven new loci associated with age-related macular degeneration.

    PubMed

    Fritsche, Lars G; Chen, Wei; Schu, Matthew; Yaspan, Brian L; Yu, Yi; Thorleifsson, Gudmar; Zack, Donald J; Arakawa, Satoshi; Cipriani, Valentina; Ripke, Stephan; Igo, Robert P; Buitendijk, Gabriëlle H S; Sim, Xueling; Weeks, Daniel E; Guymer, Robyn H; Merriam, Joanna E; Francis, Peter J; Hannum, Gregory; Agarwal, Anita; Armbrecht, Ana Maria; Audo, Isabelle; Aung, Tin; Barile, Gaetano R; Benchaboune, Mustapha; Bird, Alan C; Bishop, Paul N; Branham, Kari E; Brooks, Matthew; Brucker, Alexander J; Cade, William H; Cain, Melinda S; Campochiaro, Peter A; Chan, Chi-Chao; Cheng, Ching-Yu; Chew, Emily Y; Chin, Kimberly A; Chowers, Itay; Clayton, David G; Cojocaru, Radu; Conley, Yvette P; Cornes, Belinda K; Daly, Mark J; Dhillon, Baljean; Edwards, Albert O; Evangelou, Evangelos; Fagerness, Jesen; Ferreyra, Henry A; Friedman, James S; Geirsdottir, Asbjorg; George, Ronnie J; Gieger, Christian; Gupta, Neel; Hagstrom, Stephanie A; Harding, Simon P; Haritoglou, Christos; Heckenlively, John R; Holz, Frank G; Hughes, Guy; Ioannidis, John P A; Ishibashi, Tatsuro; Joseph, Peronne; Jun, Gyungah; Kamatani, Yoichiro; Katsanis, Nicholas; N Keilhauer, Claudia; Khan, Jane C; Kim, Ivana K; Kiyohara, Yutaka; Klein, Barbara E K; Klein, Ronald; Kovach, Jaclyn L; Kozak, Igor; Lee, Clara J; Lee, Kristine E; Lichtner, Peter; Lotery, Andrew J; Meitinger, Thomas; Mitchell, Paul; Mohand-Saïd, Saddek; Moore, Anthony T; Morgan, Denise J; Morrison, Margaux A; Myers, Chelsea E; Naj, Adam C; Nakamura, Yusuke; Okada, Yukinori; Orlin, Anton; Ortube, M Carolina; Othman, Mohammad I; Pappas, Chris; Park, Kyu Hyung; Pauer, Gayle J T; Peachey, Neal S; Poch, Olivier; Priya, Rinki Ratna; Reynolds, Robyn; Richardson, Andrea J; Ripp, Raymond; Rudolph, Guenther; Ryu, Euijung; Sahel, José-Alain; Schaumberg, Debra A; Scholl, Hendrik P N; Schwartz, Stephen G; Scott, William K; Shahid, Humma; Sigurdsson, Haraldur; Silvestri, Giuliana; Sivakumaran, Theru A; Smith, R Theodore; Sobrin, Lucia; Souied, Eric H; Stambolian, Dwight E; Stefansson, Hreinn; Sturgill-Short, Gwen M; Takahashi, Atsushi; Tosakulwong, Nirubol; Truitt, Barbara J; Tsironi, Evangelia E; Uitterlinden, André G; van Duijn, Cornelia M; Vijaya, Lingam; Vingerling, Johannes R; Vithana, Eranga N; Webster, Andrew R; Wichmann, H-Erich; Winkler, Thomas W; Wong, Tien Y; Wright, Alan F; Zelenika, Diana; Zhang, Ming; Zhao, Ling; Zhang, Kang; Klein, Michael L; Hageman, Gregory S; Lathrop, G Mark; Stefansson, Kari; Allikmets, Rando; Baird, Paul N; Gorin, Michael B; Wang, Jie Jin; Klaver, Caroline C W; Seddon, Johanna M; Pericak-Vance, Margaret A; Iyengar, Sudha K; Yates, John R W; Swaroop, Anand; Weber, Bernhard H F; Kubo, Michiaki; Deangelis, Margaret M; Léveillard, Thierry; Thorsteinsdottir, Unnur; Haines, Jonathan L; Farrer, Lindsay A; Heid, Iris M; Abecasis, Gonçalo R

    2013-04-01

    Age-related macular degeneration (AMD) is a common cause of blindness in older individuals. To accelerate the understanding of AMD biology and help design new therapies, we executed a collaborative genome-wide association study, including >17,100 advanced AMD cases and >60,000 controls of European and Asian ancestry. We identified 19 loci associated at P < 5 × 10(-8). These loci show enrichment for genes involved in the regulation of complement activity, lipid metabolism, extracellular matrix remodeling and angiogenesis. Our results include seven loci with associations reaching P < 5 × 10(-8) for the first time, near the genes COL8A1-FILIP1L, IER3-DDR1, SLC16A8, TGFBR1, RAD51B, ADAMTS9 and B3GALTL. A genetic risk score combining SNP genotypes from all loci showed similar ability to distinguish cases and controls in all samples examined. Our findings provide new directions for biological, genetic and therapeutic studies of AMD. PMID:23455636

  7. [Corticobasal degeneration: symptomatological, brain-imaging and electrophysiological studies].

    PubMed

    Morimatsu, M; Negoro, K

    1995-12-01

    Eight cases of clinically diagnosed corticobasal degeneration (CBD) were studied with reference to their symptomatology, brain-imagings and electrophysiological findings. The diagnosis was based on the combination of limb-kinetic apraxia (cortical sign), akinetic-rigid sign (extrapyramidal) and their unilateral predominance. Magnetic resonance imaging (MRI) and 123I-IMP or 99mTc-HMPAO SPECT findings were used to reinforce the diagnosis. The age at onset of 8 cases (4 males, 4 females) was 61 to 80 years (mean 66). Other common symptoms on admission consisted of dysequilibrium (8 cases), dysarthria (8), grasp reflex (6), supranuclear gaze palsy (6), tremor (6), limb dystonia (6) and alien limbs (5). MRI revealed parietal (3 cases) or frontoparietal (3) atrophy. SPECT showed decrease in cerebral blood flow in frontoparietal (3 cases) or frontoparietotemporal lobes (5). SPECT surpassed MRI to detect unilateral predominance of the lesions. With magnetic stimulation of the head and neck central motor conduction time (CMCT) was normal, while motor inhibitory periods (IPs) were significantly shorter in CBD patients compared with those in normal controls and the patients with Parkinson's disease. In 3 patients with reflex myoclonus, giant SEPs were not evoked, though with positive C-reflex, suggesting an elevated excitability of cerebral cortex unrelated to the production of giant SEPs. PMID:8752430

  8. White matter damage in frontotemporal lobar degeneration spectrum.

    PubMed

    Agosta, F; Scola, E; Canu, E; Marcone, A; Magnani, G; Sarro, L; Copetti, M; Caso, F; Cerami, C; Comi, G; Cappa, S F; Falini, A; Filippi, M

    2012-12-01

    White matter (WM) tract damage was assessed in patients with the behavioral variant frontotemporal dementia (bvFTD) and the 3 primary progressive aphasia (PPA) variants and compared with the corresponding brain atrophy patterns. Thirteen bvFTD and 20 PPA patients were studied. Tract-based spatial statistics and voxel-based morphometry were used. Patients with bvFTD showed widespread diffusion tensor magnetic resonance imaging (DT MRI) abnormalities affecting most of the WM bilaterally. In PPA patients, WM damage was more focal and varied across the 3 syndromes: left frontotemporoparietal in nonfluent, left frontotemporal in semantic, and left frontoparietal in logopenic patients. In each syndrome, DT MRI changes extended beyond the topography of gray matter loss. Left uncinate damage was the best predictor of frontotemporal lobar degeneration diagnosis versus controls. DT MRI measures of the anterior corpus callosum and left superior longitudinal fasciculus differentiated bvFTD from nonfluent cases. The best predictors of semantic PPA compared with both bvFTD and nonfluent cases were diffusivity abnormalities of the left uncinate and inferior longitudinal fasciculus. This study provides insights into the similarities and differences of WM damage in bvFTD and PPA variants. DT MRI metrics hold promise to serve as early markers of WM integrity loss that only at a later stage may be detectable by volumetric measures. PMID:21988828

  9. Clinical, imaging and electrophysiological studies of corticobasal degeneration.

    PubMed

    Huang, Kai-Ju; Lu, Ming-Kuei; Kao, Albert; Tsai, Chon-Haw

    2007-03-01

    Corticobasal degeneration (CBD) is a rare neurodegenerative disorder characterized by distinctive clinical manifestations including asymmetric akinetic-rigid syndrome and higher cortical dysfunctions. We characterized the clinical, electrophysiological and imaging presentations in four patients with CBD. All patients exhibited unilateral hand dystonia, rigidity and apraxia, but showed no significant response to levodopa therapy. Surface electromyography demonstrated short duration and stimulus-sensitive myoclonus in three of the four patients. On the other hand, there was no "giant" SEPs (somatosensory evoked potentials), and the backaveraged electroencephalography did not show any jerk-locked cortical potentials. Brain magnetic resonance imaging showed asymmetrical cortical atrophy. [99mTc]HMPAO single-photon emission computed tomography (SPECT) revealed decreased regional cerebral blood flow in the frontoparietal areas and thalamus opposite to the more severely affected limb. [99mTc]TRODAT-1 SPECT showed decreased uptake in the striatum of the affected hemisphere. These data supported that there are abnormal cortical excitability and asymmetric pathological change of the affected hemisphere in the patients with CBD. PMID:17486728

  10. Hypercholesterolemic Mice Exhibit Lymphatic Vessel Dysfunction and Degeneration

    PubMed Central

    Lim, Hwee Ying; Rutkowski, Joseph M.; Helft, Julie; Reddy, Sai T.; Swartz, Melody A.; Randolph, Gwendalyn J.; Angeli, Véronique

    2009-01-01

    Lymphatic vessels are essential for lipid absorption and transport. Despite increasing numbers of observations linking lymphatic vessels and lipids, little research has been devoted to address how dysregulation of lipid balance in the blood, ie, dyslipidemia, may affect the functional biology of lymphatic vessels. Here, we show that hypercholesterolemia occurring in apolipoprotein E-deficient (apoE?/?) mice is associated with tissue swelling, lymphatic leakiness, and decreased lymphatic transport of fluid and dendritic cells from tissue. Lymphatic dysfunction results in part from profound structural abnormalities in the lymphatic vasculature: namely, initial lymphatic vessels were greatly enlarged, and collecting vessels developed notably decreased smooth muscle cell coverage and changes in the distribution of lymphatic vessel endothelial hyaluronic acid receptor-1 (LYVE-1). Our results provide evidence that hypercholesterolemia in adult apoE?/? mice is associated with a degeneration of lymphatic vessels that leads to decreased lymphatic drainage and provides an explanation for why dendritic cell migration and, thus, immune priming, are compromised in hypercholesterolemic mice. PMID:19679879

  11. Splitting of degenerate states in one-dimensional quantum mechanics

    E-print Network

    Avik Dutt; Trisha Nath; Sayan Kar; Rajesh Parwani

    2012-06-11

    A classic no-go theorem in one-dimensional quantum mechanics can be evaded when the potentials are unbounded below, thus allowing for novel parity-paired degenerate energy bound states. We numerically determine the spectrum of one such potential and study the parametric variation of the transition wavelength between a bound state lying inside the valley of the potential and another, von Neumann-Wigner-like state, appearing above the potential maximum. We then construct a modified potential which is bounded below except when a parameter is tuned to vanish. We show how the spacing between certain energy levels gradually decreases as we tune the parameter to approach the value for which unboundedness arises, thus quantitatively linking the closeness of degeneracy to the steepness of the potential. Our results are generic to a large class of such potentials. Apart from their conceptual interest, such potentials might be realisable in mesoscopic systems thus allowing for the experimental study of the novel states. The numerical spectrum in this study is determined using the asymptotic iteration method which we briefly review.

  12. Behavior and cognition in corticobasal degeneration and progressive supranuclear palsy.

    PubMed

    Kertesz, Andrew; McMonagle, Paul

    2010-02-15

    Progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD), previously described as Parkinsonian syndromes are also cognitive disorders, and biologically related to the frontotemporal dementia or Pick's disease. PSP and CBD overlap clinically, pathologically and genetically, sharing tau haplotypes and mutations. In our series of CBD/PSP patients with cognitive presentation (n=36), primary progressive aphasia (PPA) was particularly common, but behavioral onset occurred also. CBD or PSP as motor presentations developed significant language disorder in 17/19. The underlying pathology is predictably tau positive in these clinical combinations, regardless of the presentation. Other cognitive features of CBDS include apraxia, alien hand and apathy, but often frontal lobe dementia with disinhibition develops also. CBDS also has visuospatial deficit, because of the parietal involvement. PSP was considered the prototype of subcortical dementia, with bradyphrenia, poor recall and executive deficit, but cortical features were recognized to be important also. Language testing and a behavioral inventory should be part of neuropsychological tests to facilitate diagnosis and to quantify the deficit. The clinical, genetic and pathological relationship is strong between CBD /PSP and the aphasic and behavioral components of the Pick complex. PMID:19733862

  13. Heavy-fermion instability in double-degenerate plasmas

    SciTech Connect

    Akbari-Moghanjoughi, M. [Department of Physics, Faculty of Sciences, Azarbaijan University of Tarbiat Moallem, 51745-406 Tabriz (Iran, Islamic Republic of)

    2012-07-15

    In this work, we study the propagations of normal frequency modes for quantum hydrodynamic waves in the linear limit and introduce a new kind of instability in a double-degenerate plasma. Three different regimes, namely, low, intermediate, and high magnetic field strengths are considered which span the applicability of the work to a wide variety of environments. Distinct behavior is observed for different regimes, for instance, in the laboratory-scale field regime no frequency-mode instability occurs unlike those of intermediate and high magnetic-field strength regimes. It is also found that the instability of this kind is due to the heavy-fermions which appear below a critical effective-mass parameter ({mu}{sub cr}={radical}(3)) and that the responses of the two (lower and upper frequency) modes to fractional effective-mass change in different effective-mass parameter ranges (below and above the critical value) are quite opposite to each other. It is shown that the heavy-fermion instability due to extremely high magnetic field such as that encountered for a neutron-star crust can lead to confinement of stable propagations in both lower and upper frequency modes to the magnetic poles. Current study can have important implications for linear wave dynamics in both laboratory and astrophysical environments possessing high magnetic fields.

  14. Hippocampal degeneration in patients with amyotrophic lateral sclerosis.

    PubMed

    Abdulla, Susanne; Machts, Judith; Kaufmann, Jörn; Patrick, Karina; Kollewe, Katja; Dengler, Reinhard; Heinze, Hans-Jochen; Petri, Susanne; Vielhaber, Stefan; Nestor, Peter J

    2014-11-01

    There is increasing appreciation of non-motor system involvement in amyotrophic lateral sclerosis (ALS), although its full extent and clinical significance remains to be established. This study tested the hypothesis that memory impairment in patients with ALS is related to hippocampal degeneration. Consecutive patients with ALS (58) and 29 matched controls participated in standardized neuropsychological assessment and magnetic resonance imaging. Patients with ALS performed worse in global cognitive functioning and executive and verbal memory tests (p < 0.05). The hippocampus was manually segmented in each hemisphere, and volumes were calculated with correction for intracranial volume. Analysis of covariance, controlled for the effect of age and education years, showed significantly smaller hippocampal volume on the right (p = 0.004) in patients with ALS. Verbal memory test performance correlated with the left hippocampal volume in patients with ALS (p < 0.05), although there was no significant correlation with tests of executive function and clinical variables underscoring the specificity of the present findings. Hippocampal volume loss and its correlation with the severity of verbal memory impairment highlight significant hippocampal involvement which can occur as a non-motor deficit in patients with ALS. PMID:25004891

  15. Survival in frontotemporal lobar degeneration in a Korean population.

    PubMed

    Kang, Sue J; Cha, Kyung Ryeol; Seo, Sang Won; Kim, Eun A; Cheong, Hae-Kwan; Kim, Eun-Joo; Na, Duk L; Jeong, Jee H

    2010-01-01

    Frontotemporal lobar degeneration (FTLD) can be subdivided into frontotemporal dementia (FTD), FTD combined with motor neuron disease (FTD-MND), semantic dementia (SD), and progressive nonfluent aphasia (PNFA). FTLD has been considered a rare disorder, and its' demographic and survival data have rarely been studied in Asian population. A survival analysis using the Kaplan-Meier method was performed for 121 consecutive patients with clinically diagnosed FTLD who attended the Memory Disorder Clinic at Samsung Medical Center in Seoul, Republic of Korea, between January 1995 and September 2006. The overall median survival from the onset of the first symptom was 9.6 years (95% CI=8.3-10.8 y). The survival was shortest in FTD-MND (3 y) and longest in SD (11.3 y). The median survival time of FTD (9.8 y) was shorter than that of SD and longer than that of FTD-MND and PNFA. The use of the Cox proportional-hazards model to examine the effect of demographics on survival revealed that only age at onset was associated with survival. In general, our data are comparable with those from the Western countries. However, the female proportion was greater across all subtypes of FTLD and the survival of patients with PNFA was shorter than those of other groups. PMID:20625272

  16. Degenerate gaugino mass region and mono-boson collider signatures

    NASA Astrophysics Data System (ADS)

    Anandakrishnan, Archana; Carpenter, Linda M.; Raby, Stuart

    2014-09-01

    In this paper we discuss search strategies at the LHC for light electroweak gauginos which are mostly wino-like, Higgsino-like or an admixture. These states are typically degenerate with decay products that are less energetic and hence difficult to detect. In addition, their production cross sections at a hadron collider are suppressed compared to colored states such as the gluinos. In order to detect these states one needs to trigger on initial-or final-state radiation. Many previous analyses have focussed on mono-jet and mono-photon triggers. In this paper we argue and show that these triggers are unlikely to succeed, due to the large background from QCD backgrounds for the mono-jet searches and the fact that the pT distribution of the mono-photons are rapidly decreasing functions of pT. We show this with both an analytic calculation of photons in the initial-state radiation and also a detailed numerical analysis. We then argue that mono-Z triggers, from Z decaying into charged leptons may well provide the best search strategy, in particular for Higgsino-like and mixed cases.

  17. Seven New Loci Associated with Age-Related Macular Degeneration

    PubMed Central

    2013-01-01

    Age-related macular degeneration (AMD) is a common cause of blindness in older individuals. To accelerate understanding of AMD biology and help design new therapies, we executed a collaborative genomewide association study, examining >17,100 advanced AMD cases and >60,000 controls of European and Asian ancestry. We identified 19 genomic loci associated with AMD with p<5×10?8 and enriched for genes involved in regulation of complement activity, lipid metabolism, extracellular matrix remodeling and angiogenesis. Our results include 7 loci reaching p<5×10?8 for the first time, near the genes COL8A1/FILIP1L, IER3/DDR1, SLC16A8, TGFBR1, RAD51B, ADAMTS9/MIR548A2, and B3GALTL. A genetic risk score combining SNPs from all loci displayed similar good ability to distinguish cases and controls in all samples examined. Our findings provide new directions for biological, genetic and therapeutic studies of AMD. PMID:23455636

  18. Age-Related Macular Degeneration: A Scientometric Analysis

    PubMed Central

    Ramin, Shahrokh; Soheilian, Masoud; Habibi, Gholamreza; Ghazavi, Roghayeh; Gharebaghi, Reza; Heidary, Fatemeh

    2015-01-01

    Age-related macular degeneration (ARMD) is a major cause of central blindness among working aged adults across the world. Systematic research planning on any subject, including ARMD is in need of solid data regarding previous efforts in this field and to identify the gaps in the research. This study aimed to elucidate the most important trends, directions, and gap in this subject. The data extracted from the Institute for Scientific Information were used to perform a bibliometric analysis of the scientific productions (1993–2013) about ARMD. Specific parameters related to ARMD were analyzed to obtain a view of the topic’s structure, history, and document relationships. Additionally, the trends and authors in the most influential publications were analyzed. The number of articles in this field was found constantly increasing. Most highly cited articles addressed genetic epidemiology and clinical research topics in this field. During the past 3 years, there has been a trend toward biomarker research. Through performing the first scientometric survey on ARMD research, we analyzed the characteristics of papers and the trends in scientific production. We also identified some of the critical gaps in the current research efforts that would help in large-scale research strategic planning.

  19. Variation in malaria transmission intensity in seven sites throughout Uganda.

    PubMed

    Okello, Paul Edward; Van Bortel, Wim; Byaruhanga, Anatol Maranda; Correwyn, Anne; Roelants, Patricia; Talisuna, Ambrose; D'Alessandro, Umberto; Coosemans, Marc

    2006-08-01

    Knowledge of the baseline malaria transmission in a given environment is important to guide malaria control interventions. However, in Uganda, recent information on malaria transmission intensity is lacking. Therefore, a 1-year entomological study was conducted in seven ecologically different sites throughout the country to assess spatial and temporal patterns in malaria transmission intensity. Anopheles gambiae sensu stricto was the main vector in five of the seven study sites, and An. funestus was the most important vector in the two other sites. In a peri-urban village, An. arabiensis contributed substantially to malaria transmission. Clear differences in annual entomological inoculation rates (AEIR) were observed between the study sites, ranging from 4 infective bites per person per year in the southwestern part of the country to >1,500 infective bites per person per year in a swampy area near the Nile River. Between villages with parasite prevalences of >or= 80% in children between 1 and 9 years old, a 4-fold difference in AEIR was observed. Based on the observed behavior of the vectors, insecticide-treated bed nets will be highly effective in controlling malaria. However, in the high transmission areas, additional measures will be needed to reduce the malaria burden to acceptable levels. PMID:16896122

  20. Sites internet

    PubMed

    Couderc

    2000-07-01

    http://biotribune.com/ Biotribune.com ou la biologie medicale sur internet. Ce site est concu comme un portail sur la biologie clinique. Accueil d'internautes sur une page comportant, entre autres, les rubriques : actualite, evenements, revue des connaissances, rubrique juridique et petites annonces. Biotribune propose regulierement des dossiers rediges par des specialistes comportant une mise a jour des connaissances orientee sur l'interet diagnostique des tests de biologie clinique. Le site propose egalement une revue de presse scientifique avec des resumes courts d'articles parus dans les grands journaux internationaux tels que The Lancet, New England Journal of Medicine, Science, etc. Vous pouvez aussi y tester vos connaissances grace a des cas cliniques et des QCM. Ce site propose egalement des petites annonces pratiques pour les laboratoires de ville (remplacement, materiel d'occasion, etc.). Les problemes touchant l'assurance qualite, les RMO et la nomenclature font egalement l'objet d'information et de commentaires. Enfin, vous pourrez vous inscrire a l'un des forums proposes : discussion biomedicale ou opinion et reaction sur les sujets touchant au professionnel de la biologie medicale. En conclusion, un site complet et agreable que l'on souhaite voir s'enrichir et se renouveler regulierement. http://www.arcol.asso.fr Site du Comite francais de coordination de recherche sur l'atherosclerose et le cholesterol (Arcol). Ce site s'adresse a la fois aux cliniciens, aux biologistes et aux non-specialistes interesses par la pathologie cardio-vasculaire et ses traitements. On y trouve des rubriques tres didactiques sur la physiopathologie et les facteurs de risque de l'atherosclerose, la prise en charge nutritionnelle et medicamenteuse des patients. On peut tester ses connaissances a l'aide des nombreux cas cliniques richement commentes. Ce site regulierement mis a jour contient egalement les recommandations nationales et internationales sur la prise en charge du patient hyperlipidemique. On y trouve, bien sur, toutes les rubriques telles que : agenda des congres, lien avec les autres sites web, bibliographie, etc. Un index par mots cles permet une recherche efficace. Un site indispensable a consulter pour tous ceux qui s'interessent aux lipoproteines et a l'atherosclerose. n R. Couderc PMID:10932060

  1. X-ray and UV radiation from accreting nonmagnetic degenerate dwarfs. II

    NASA Technical Reports Server (NTRS)

    Kylafis, N. D.; Lamb, D. Q.

    1982-01-01

    Numerical calculations of X-ray and UV emission from accreting nonmagnetic degenerate dwarfs are reported, which span the entire range of accretion rates and stellar masses. Calculations include the effects of bremsstrahlung, Compton cooling, radiation pressure, albedo of the stellar surface, Compton degradation and free-free abscription of the X-ray spectrum by the accreting matter. Maximum X-ray luminosity for degenerate dwarfs undergoing spherical accretion is found to be 2.2 x 10 to the 36th ergs/s, which is little changed if accretion occurs radially over only a fraction of the stellar surface, so that the emitted radiation escapes without significant scattering. The temperature characterizing the X-ray spectra produced by degenerate dwarfs strongly depends on the stellar mass and the accretion rate, and it is suggested that the correlation between spectral temperature and luminosity is an important signature of degenerate X-ray sources.

  2. Creating a quantum degenerate gas of stable molecules via weak photoassociation

    NASA Astrophysics Data System (ADS)

    Mackie, Matt; Phou, Pierre

    2010-07-01

    Quantum degenerate molecules represent a new paradigm for fundamental studies and practical applications. Association of already quantum degenerate atoms into molecules provides a crucial shortcut around the difficulty of cooling molecules to ultracold temperatures. Whereas association can be induced with either laser or magnetic fields, photoassociation requires impractical laser intensity to overcome poor overlap between the atom pair and molecular wave functions, and experiments are currently restricted to magnetoassociation. Here we model realistic production of a quantum degenerate gas of stable molecules via two-photon photoassociation of Bose-condensed atoms. An adiabatic change of the laser frequency converts the initial atomic condensate almost entirely into stable molecular condensate, even for low-intensity lasers. Results for dipolar LiNa provide an upper bound on the necessary photoassociation laser intensity for alkali-metal atoms ~30 W/cm2, indicating a feasible path to quantum degenerate molecules beyond magnetoassociation.

  3. The Retromer Complex Is Required for Rhodopsin Recycling and Its Loss Leads to Photoreceptor Degeneration

    PubMed Central

    Wang, Shiuan; Tan, Kai Li; Agosto, Melina A.; Xiong, Bo; Yamamoto, Shinya; Sandoval, Hector; Jaiswal, Manish; Bayat, Vafa; Zhang, Ke; Charng, Wu-Lin; David, Gabriela; Duraine, Lita; Venkatachalam, Kartik; Wensel, Theodore G.; Bellen, Hugo J.

    2014-01-01

    Rhodopsin mistrafficking can cause photoreceptor (PR) degeneration. Upon light exposure, activated rhodopsin 1 (Rh1) in Drosophila PRs is internalized via endocytosis and degraded in lysosomes. Whether internalized Rh1 can be recycled is unknown. Here, we show that the retromer complex is expressed in PRs where it is required for recycling endocytosed Rh1 upon light stimulation. In the absence of subunits of the retromer, Rh1 is processed in the endolysosomal pathway, leading to a dramatic increase in late endosomes, lysosomes, and light-dependent PR degeneration. Reducing Rh1 endocytosis or Rh1 levels in retromer mutants alleviates PR degeneration. In addition, increasing retromer abundance suppresses degenerative phenotypes of mutations that affect the endolysosomal system. Finally, expressing human Vps26 suppresses PR degeneration in Vps26 mutant PRs. We propose that the retromer plays a conserved role in recycling rhodopsins to maintain PR function and integrity. PMID:24781186

  4. Creating a quantum degenerate gas of stable molecules via weak photoassociation

    SciTech Connect

    Mackie, Matt; Phou, Pierre [Department of Physics, Temple University, Philadelphia, Pennsylvania 19122 (United States)

    2010-07-15

    Quantum degenerate molecules represent a new paradigm for fundamental studies and practical applications. Association of already quantum degenerate atoms into molecules provides a crucial shortcut around the difficulty of cooling molecules to ultracold temperatures. Whereas association can be induced with either laser or magnetic fields, photoassociation requires impractical laser intensity to overcome poor overlap between the atom pair and molecular wave functions, and experiments are currently restricted to magnetoassociation. Here we model realistic production of a quantum degenerate gas of stable molecules via two-photon photoassociation of Bose-condensed atoms. An adiabatic change of the laser frequency converts the initial atomic condensate almost entirely into stable molecular condensate, even for low-intensity lasers. Results for dipolar LiNa provide an upper bound on the necessary photoassociation laser intensity for alkali-metal atoms {approx}30 W/cm{sup 2}, indicating a feasible path to quantum degenerate molecules beyond magnetoassociation.

  5. Creating a Quantum Degenerate Gas of Stable Molecules via Weak Photoassociation

    E-print Network

    Matt Mackie; Pierre Phou

    2010-08-10

    Quantum degenerate molecules represent a new paradigm for fundamental studies and practical applications. Association of already quantum degenerate atoms into molecules provides a crucial shortcut around the difficulty of cooling molecules to ultracold temperatures. Whereas association can be induced with either laser or magnetic fields, photoassociation requires impractical laser intensity to overcome poor overlap between the atom pair and molecular wavefunctions, and experiments are currently restricted to magnetoassociation. Here we model realistic production of a quantum degenerate gas of stable molecules via two-photon photoassociation of Bose-condensed atoms. An adiabatic change of the laser frequency converts the initial atomic condensate almost entirely into stable molecular condensate, even for low-intensity lasers. Results for dipolar LiNa provide an upper bound on the necessary photoassociation laser intensity for alkali-metal atoms ~30 W/cm^2, indicating a feasible path to quantum degenerate molecules beyond magnetoassociation.

  6. Quantum time ordering and degeneracy. II: Coherent population transfer between degenerate states

    E-print Network

    Kh. Yu. Rakhimov; Kh. Kh. Shakov; J. H. McGuire

    2003-08-02

    We find conditions required to achieve complete population transfer, via coherent population trapping, from an initial state to a designated final state at a designated time in a degenerate $n$-state atom, where transitions are caused by an external interaction. In systems with degenerate states there is no time ordering. Analytic expressions have been found for transition probabilities in a degenerate $n$-state atom interacting with a strong external field that gives a common time dependence to all of the transition matrix elements. Except for solving a simple $n^{th}$ order equation to determine eigenvalues of dressed states, the method is entirely analytic. These expressions may be used to control electron populations in degenerate $n$-state atoms. Examples are given for $n=2$ and $n=3$.

  7. Alpha-Synuclein Disrupted Dopamine Homeostasis Leads to Dopaminergic Neuron Degeneration in Caenorhabditis elegans

    E-print Network

    Cao, Pengxiu; Yuan, Yiyuan; Pehek, Elizabeth A.; Moise, Alexander R.; Huang, Ying; Palczewski, Krzysztof; Feng, Zhaoyang

    2010-02-19

    Disruption of dopamine homeostasis may lead to dopaminergic neuron degeneration, a proposed explanation for the specific vulnerability of dopaminergic neurons in Parkinson's disease. While expression of human ?-synuclein in C. elegans results...

  8. Investigating the genetic and molecular basis of age-related macular degeneration 

    E-print Network

    Stanton, Chloe May

    2012-06-30

    Age-related macular degeneration (AMD) is the leading cause of blindness worldwide, affecting an estimated 50 million individuals aged over 65 years. Environmental and genetic risk-factors contribute to the development ...

  9. Quantum degenerate Bose-Fermi mixture of chemically different atomic species with widely tunable interactions

    E-print Network

    Park, Jee Woo

    We have created a quantum degenerate Bose-Fermi mixture of [superscript 23]Na and [superscript 40]K with widely tunable interactions via broad interspecies Feshbach resonances. Over 30 Feshbach resonances between [superscript ...

  10. The retromer complex is required for rhodopsin recycling and its loss leads to photoreceptor degeneration.

    PubMed

    Wang, Shiuan; Tan, Kai Li; Agosto, Melina A; Xiong, Bo; Yamamoto, Shinya; Sandoval, Hector; Jaiswal, Manish; Bayat, Vafa; Zhang, Ke; Charng, Wu-Lin; David, Gabriela; Duraine, Lita; Venkatachalam, Kartik; Wensel, Theodore G; Bellen, Hugo J

    2014-04-01

    Rhodopsin mistrafficking can cause photoreceptor (PR) degeneration. Upon light exposure, activated rhodopsin 1 (Rh1) in Drosophila PRs is internalized via endocytosis and degraded in lysosomes. Whether internalized Rh1 can be recycled is unknown. Here, we show that the retromer complex is expressed in PRs where it is required for recycling endocytosed Rh1 upon light stimulation. In the absence of subunits of the retromer, Rh1 is processed in the endolysosomal pathway, leading to a dramatic increase in late endosomes, lysosomes, and light-dependent PR degeneration. Reducing Rh1 endocytosis or Rh1 levels in retromer mutants alleviates PR degeneration. In addition, increasing retromer abundance suppresses degenerative phenotypes of mutations that affect the endolysosomal system. Finally, expressing human Vps26 suppresses PR degeneration in Vps26 mutant PRs. We propose that the retromer plays a conserved role in recycling rhodopsins to maintain PR function and integrity. PMID:24781186

  11. On the Existence of the Composite Curve near a Degeneration Point

    E-print Network

    the composite curve near degeneration points of nonlinear #12;elds. For this purpose we introduce the Hugoniot locus H(u #3; ) which is composed of all states u 2 D such that the Rankine{Hugoniot jump condition #27

  12. A Free Boundary Problem for a Quasilinear Degenerate Elliptic Equation: Regular

    E-print Network

    Canic, Suncica

    ; its position is the solution to a free boundary problem for the degenerate equation. Using the Rankine­Hugoniot Rankine­Hugoniot relations. For the first time, in this paper, we combine these approaches and show

  13. Determination of dispersion and nonlinear coefficients of photonic crystal fibers by degenerated FWM method

    Microsoft Academic Search

    Wenping Ge; Aoxiang Lin; Cyril Guintrand; Jean Toulouse

    2010-01-01

    By using degenerated four wave mixing (FWM) method and counting the efficiency of the newly created frequency, we easily obtained dispersion, dispersion slope and nonlinear coefficients by fitting the experimental data with several well-known functions.

  14. Calcium Release from Intra-Axonal Endoplasmic Reticulum Leads to Axon Degeneration through Mitochondrial Dysfunction

    PubMed Central

    Villegas, Rosario; Martinez, Nicolas W.; Lillo, Jorge; Pihan, Phillipe; Hernandez, Diego; Twiss, Jeffery L.

    2014-01-01

    Axonal degeneration represents an early pathological event in neurodegeneration, constituting an important target for neuroprotection. Regardless of the initial injury, which could be toxic, mechanical, metabolic, or genetic, degeneration of axons shares a common mechanism involving mitochondrial dysfunction and production of reactive oxygen species. Critical steps in this degenerative process are still unknown. Here we show that calcium release from the axonal endoplasmic reticulum (ER) through ryanodine and IP3 channels activates the mitochondrial permeability transition pore and contributes to axonal degeneration triggered by both mechanical and toxic insults in ex vivo and in vitro mouse and rat model systems. These data reveal a critical and early ER-dependent step during axonal degeneration, providing novel targets for axonal protection in neurodegenerative conditions. PMID:24849352

  15. A STRONGLY DEGENERATE CONVECTION-DIFFUSION PROBLEM MODELING CENTRIFUGATION OF FLOCCULATED SUSPENSIONS

    E-print Network

    A STRONGLY DEGENERATE CONVECTION-DIFFUSION PROBLEM MODELING CENTRIFUGATION OF FLOCCULATED of occulated suspen- sions. A modi#12;cation of the generalized upwind method is employed to solve the initial

  16. Loss of MEC-17 Leads to Microtubule Instability and Axonal Degeneration

    PubMed Central

    Neumann, Brent; Hilliard, Massimo A.

    2014-01-01

    SUMMARY Axonal degeneration arises as a consequence of neuronal injury and is a common hallmark of a number of neurodegenerative diseases. However, the genetic causes and the cellular mechanisms that trigger this process are still largely unknown. Based on forward genetic screening in C. elegans, we have identified the ?-tubulin acetyltransferase gene mec-17 as causing spontaneous, adult-onset, and progressive axonal degeneration. Loss of MEC-17 leads to microtubule instability, a reduction in mitochondrial number, and disrupted axonal transport, with altered distribution of both mitochondria and synaptic components. Furthermore, mec-17-mediated axonal degeneration occurs independently from its acetyltransferase domain; is enhanced by mutation of coel-1, a tubulin-associated molecule; and correlates with the animal’s body length. This study therefore identifies a critical role for the conserved microtubule-associated protein MEC-17 in preserving axon integrity and preventing axonal degeneration. PMID:24373971

  17. Natural guardians of the race: heredity, hygiene, alcohol, and degeneration in Scottish Psychiatry, c. 1860 – 1920 

    E-print Network

    Wood, James Anthony

    2012-06-29

    This thesis investigates the ways in which hereditary degeneration was discussed by Scottish psychiatrists in the late nineteenth and early twentieth centuries with particular reference to the anti-alcohol debate. I ...

  18. Axons Degenerate in the Absence of Mitochondria in C. elegans

    E-print Network

    Rawson, Randi L.

    Many neurodegenerative disorders are associated with mitochondrial defects [1, 2 and 3]. Mitochondria can play an active role in degeneration by releasing reactive oxygen species and apoptotic factors [4, 5, 6 and 7]. ...

  19. THE KAROUBI ENVELOPE AND LEE'S DEGENERATION OF KHOVANOV DROR BARNATAN AND SCOTT MORRISON

    E-print Network

    Bar-Natan, Dror

    THE KAROUBI ENVELOPE AND LEE'S DEGENERATION OF KHOVANOV HOMOLOGY DROR BAR­NATAN AND SCOTT MORRISON­NATAN AND SCOTT MORRISON Let us sketch our results now; the relevant terminology (which closely follows [2

  20. Reorganization of Visual Processing in Macular Degeneration Is Not Specific to the "Preferred Retinal Locus"

    E-print Network

    Baker, Chris I.

    Recent work has shown that foveal cortex, deprived of its normal bottom-up input as a result of macular degeneration (MD), begins responding to stimuli presented to a peripheral retinal location. However, these studies ...

  1. Exponential Mixing of the 3D Stochastic Navier-Stokes Equations Driven by Mildly Degenerate Noises

    SciTech Connect

    Albeverio, Sergio [Bonn University, Department of Applied Mathematics (Germany); Debussche, Arnaud, E-mail: arnaud.debussche@bretagne.ens-cachan.fr [ENS Cachan Bretagne and IRMAR Campus de Ker Lann (France); Xu Lihu, E-mail: Lihu.Xu@brunel.ac.uk [Brunel University, Mathematics Department (United Kingdom)

    2012-10-15

    We prove the strong Feller property and exponential mixing for 3D stochastic Navier-Stokes equation driven by mildly degenerate noises (i.e. all but finitely many Fourier modes being forced) via a Kolmogorov equation approach.

  2. Atypical multiple system atrophy is a new subtype of frontotemporal lobar degeneration: frontotemporal lobar degeneration associated with ?-synuclein.

    PubMed

    Aoki, Naoya; Boyer, Philip J; Lund, Cheryl; Lin, Wen-Lang; Koga, Shunsuke; Ross, Owen A; Weiner, Myron; Lipton, Anne; Powers, James M; White, Charles L; Dickson, Dennis W

    2015-07-01

    Multiple system atrophy (MSA) is a sporadic neurodegenerative disease clinically characterized by cerebellar signs, parkinsonism, and autonomic dysfunction. Pathologically, MSA is an ?-synucleinopathy affecting striatonigral and olivopontocerebellar systems, while neocortical and limbic involvement is usually minimal. In this study, we describe four patients with atypical MSA with clinical features consistent with frontotemporal dementia (FTD), including two with corticobasal syndrome, one with progressive non-fluent aphasia, and one with behavioral variant FTD. None had autonomic dysfunction. All had frontotemporal atrophy and severe limbic ?-synuclein neuronal pathology. The neuronal inclusions were heterogeneous, but included Pick body-like inclusions. The latter were strongly associated with neuronal loss in the hippocampus and amygdala. Unlike typical Pick bodies, the neuronal inclusions were positive on Gallyas silver stain and negative on tau immunohistochemistry. In comparison to 34 typical MSA cases, atypical MSA had significantly more neuronal inclusions in anteromedial temporal lobe and limbic structures. While uncommon, our findings suggest that MSA may present clinically and pathologically as a frontotemporal lobar degeneration (FTLD). We suggest that this may represent a novel subtype of FTLD associated with ?-synuclein (FTLD-synuclein). PMID:25962793

  3. Degeneration of solventogenic Clostridium strains monitored by Fourier transform infrared spectroscopy of bacterial cells

    Microsoft Academic Search

    KC Schuster; R Goodacre; JR Gapes; M Young

    2001-01-01

      Strain degeneration in solventogenic clostridia is a known problem in the technical acetone–butanol fermentation bioprocess,\\u000a especially in the continuous process mode. Clostridial strain degeneration was studied by Fourier transform infrared (FT-IR)\\u000a spectroscopy of the bacterial cells. Degenerative variant formation in two strains, Clostridium beijerinckii NCIMB 8052 and Clostridium species AA332, was detected spectroscopically. Colonies on solid media were sampled, or

  4. Autoradiography with [ 3 H]PK11195 of spinal tract degeneration in amyotrophic lateral sclerosis

    Microsoft Academic Search

    H. H. Sitte; J. Wanschitz; H. Budka; M. L. Berger

    2001-01-01

    The diagnostic hallmarks of amyotrophic lateral sclerosis (ALS) are degeneration of upper and lower motor neurons and of corticospinal tracts. Here, we demonstrate the suitability of the gliosis marker [3H]PK11195 for quantitative evaluation of tract degeneration in ALS in vitro. Binding of [3H]PK11195 was increased in lateral and ventral white matter of ALS spinal cords but not in the anterior

  5. The Ultraviolet and X-Ray Spectra of Accreting Degenerate Dwarfs

    Microsoft Academic Search

    James Noboru Imamura

    1981-01-01

    The discoveries that several degenerate dwarfs in mass transfer binary systems emit X-rays have shown that accreting degenerate dwarfs comprise an important class of celestial X-ray sources. The X-rays are produced when the accreting plasma strikes the dwarf's surface. The detailed nature of the UV and X-ray spectra due to this process must be determined by numerical integrations of the

  6. Exchange-Degenerate Scheme for Baryonic Regge Poles in Connection with Quark-Line Diagrams

    Microsoft Academic Search

    Toshihiro Yoshida

    1971-01-01

    The exchange-degenerate solutions for the constraints, which come from the requirement of duality and the absence of exotic resonances, on the couplings of baryonic Regge-poles are investigated in connection with quark-line diagrams. Diagrams of H-type correspond to the solutions, whereas those of Z-type should disappear in the fully exchange-degenerate scheme. It is also shown that factorization holds among H-type diagrams

  7. Wallerian degeneration and axonal regeneration after sciatic nerve crush are altered in ICAM-1-deficient mice

    Microsoft Academic Search

    Matthias Kirsch; Marianella Campos Friz; Vassilios I. Vougioukas; Hans-Dieter Hofmann

    2009-01-01

    The intercellular cell adhesion molecule-1 (ICAM-1) has been implicated in the recruitment of immune cells during inflammatory\\u000a processes. Previous studies investigating its involvement in the process of Wallerian degeneration and focusing on its potential\\u000a role in macrophage recruitement have come to controversial conclusions. To examine whether Wallerian degeneration is altered\\u000a in the absence of ICAM-1, we have analyzed changes in

  8. cGMP-dependent cone photoreceptor degeneration in the cpfl1 mouse retina.

    PubMed

    Trifunovi?, Dragana; Dengler, Katja; Michalakis, Stylianos; Zrenner, Eberhart; Wissinger, Bernd; Paquet-Durand, François

    2010-09-01

    Inherited retinal degeneration affecting both rod and cone photoreceptors constitutes one of the leading causes of blindness in the developed world. Such degeneration is at present untreatable, and the underlying neurodegenerative mechanisms are unknown, even though certain genetic causes have been established. The rd1 mouse is one of the best characterized animal models for rod photoreceptor degeneration, whereas the cpfl1 mouse is a recently discovered model for cone cell death. Because both animal models are affected by functionally similar mutations in the rod and cone phosphodiesterase 6 genes, respectively, we asked whether the mechanisms of photoreceptor degeneration in these two mouse lines share common pathways. In the present study, we followed the temporal progression of photoreceptor degeneration in the cpfl1 retina, correlated it with specific metabolic markers, and compared it with the wild-type and the rd1 situation. Similar to corresponding rd1 observations, cpfl1 cone photoreceptor cell death was associated with an accumulation of cyclic guanosine monophosphate (cGMP), activity of calpains, and phosphorylation of vasodilator-stimulated protein (VASP). Cone degeneration progressed rapidly, with a peak in cell death around postnatal day 24. Furthermore, cpfl1 cone photoreceptor migration during early postnatal development was delayed significantly compared with the corresponding wild-type retina. The finding that rod and cone photoreceptor degeneration was associated with the same metabolic markers suggests that in both cell types similar degenerative mechanisms are active. This raises the possibility that equivalent neuroprotective strategies may be used to prevent both rod and cone photoreceptor degeneration. PMID:20593360

  9. Guidance value of MRI for transsphenoidal surgery of pituitary adenomas with cystic degeneration

    PubMed Central

    Xiao, Deyong; Wang, Shousen; Zhao, Lin; Wei, Liangfeng; Hong, Jingfang; Zhong, Qun; Yu, Yinghao; Huang, Yinxing

    2015-01-01

    Objective: This study is to evaluate the surgical outcomes of transsphenoidal surgery in pituitary adenoma (PA) patients with cystic degeneration by using MRI. Methods: Eighty-three patients with surgically and pathologically confirmed PA were enrolled. They were divided into three groups according to preoperative MR images: substantive adenoma group (n = 40), cystic degeneration without fluid-fluid level group (n = 19), cystic degeneration with fluid-fluid level group (n = 24). The PA was removed by transsphenoidal surgery and the surgical outcomes were retrospectively compared. Results: The number of cases with abundant blood supply was 17 cases (42.5%) in substantive adenoma group, 13 cases (68.4%) in cystic degeneration without fluid-fluid level group and 16 cases (66.7%) in cystic degeneration with fluid-fluid level group. Blood supply in cystic degeneration with fluid-fluid level group was significantly richer than that in substantive adenoma group (P < 0.05). Peritumoral adhesion was significantly greater in cystic degeneration with fluid-fluid level group than in substantive adenoma group. And, PA with fluid-fluid level has significantly lower tumor total resection rate and MVD as well as higher recurrence rate (P < 0.05). Differences in cerebrospinal fluid leakage and postoperative diabetes insipidus were both not significant among the three groups (P > 0.05). Conclusions: Compared with other types of PA, cystic degeneration with fluid-fluid level were often richer in blood supply, greater in adhesion with peritumoral structures and easier to be found with tumor residual. Thus, more patience should be needed during the surgeries and more dynamic reviews are required postoperatively.

  10. A quasi-conforming nine-node degenerated shell finite element

    Microsoft Academic Search

    Yupu Guan; Limin Tang

    1992-01-01

    Based on the Hu-Washizu variational principle and the concept of degenerated solid shell elements, a quasi-conforming or hybrid\\/mixed nine-node degenerated shell finite element CSH9 has been developed. This finite element is completely free from shear and membrane locking phenomena, and spurious kinematic modes are globally suppressed. Numerical tests indicate that the finite element is highly accurate and effective.

  11. Degeneration of Trigonometric Dynamical Difference Equations for Quantum Loop Algebras to Trigonometric Casimir Equations for Yangians

    NASA Astrophysics Data System (ADS)

    Balagovi?, Martina

    2015-03-01

    We show that, under Drinfeld's degeneration (Proceedings of the International Congress of Mathematicians. American Mathematical Society, Providence, pp 798-820, 1987) of quantum loop algebras to Yangians, the trigonometric dynamical difference equations [Etingof and Varchenko (Adv Math 167:74-127, 2002)] for the quantum affine algebra degenerate to the trigonometric Casimir differential equations [Toledano Laredo (J Algebra 329:286-327, 2011)] for Yangians.

  12. Corticobasal degeneration with neither argyrophilic inclusions nor tau abnormalities: a new subgroup?

    Microsoft Academic Search

    K. Kawasaki; K. Iwanaga; K. Wakabayashi; M. Yamada; H. Nagai; J. Idezuka; Y. Homma; F. Ikuta

    1996-01-01

    In corticobasal degeneration (CBD), cerebral cortical neuronal loss with achromasia and degeneration of the subcortical nuclei,\\u000a particularly the substantia nigra, are common. Recent studies have suggested that the occurrence of argyrophilic nigral inclusions,\\u000a resembling the neurofibrillary tangles found in progressive supranuclear palsy, and widespread tau abnormalities may be features\\u000a of CBD. We studied brain tissues from two patients in whom

  13. Does anterior lumbar interbody fusion promote adjacent degeneration in degenerative disc disease? A finite element study

    Microsoft Academic Search

    Shujie Tang; Brandon J. Rebholz

    2011-01-01

    Background  The increase in the number of anterior lumbar interbody fusions being performed carries with it the potential for the long-term\\u000a complication of adjacent segmental degeneration. While its exact mechanism remains uncertain, adjacent segment degeneration\\u000a has become much more widespread. Using a nonlinear, three-dimensional finite element model to analyze and compare the biomechanical\\u000a influence of anterior lumbar interbody fusion and lumbar

  14. Methyl group deficiency in nerve tissue: A hypothesis to explain the lesion of subacute combined degeneration

    Microsoft Academic Search

    J. J. Dinn; D. G. Weir; S. McCann; B. Reed; P. Wilson; J. M. Scott

    1980-01-01

    Summary  The pattern of degeneration induced in the spinal cords and peripheral nerves of 4 monkeys exposed to nitrous oxide resembles\\u000a subacute combined degeneration found in man with untreated vitamin B12 deficiency. Our findings indicate that nitrous oxide directly inhibits the folate dependent methionine synthetase reaction.\\u000a This ultimately results in ‘methyl group deficiency’ with consequent defective remethylation of essential constituents of

  15. Quantum Degenerate Two-Species Fermi-Fermi Mixture Coexisting with a Bose-Einstein Condensate

    Microsoft Academic Search

    M. Taglieber; A.-C. Voigt; T. Aoki; T. W. Hänsch; K. Dieckmann

    2008-01-01

    We report on the generation of a quantum degenerate Fermi-Fermi mixture of two different atomic species. The quantum degenerate mixture is realized employing sympathetic cooling of fermionic Li6 and K40 gases by an evaporatively cooled bosonic Rb87 gas. We describe the combination of trapping and cooling methods that proved crucial to successfully cool the mixture. In particular, we study the

  16. Experimental model of intervertebral disc degeneration by needle puncture in Wistar rats

    PubMed Central

    Issy, A.C.; Castania, V.; Castania, M.; Salmon, C.E.G.; Nogueira-Barbosa, M.H.; Bel, E. Del; Defino, H.L.A.

    2013-01-01

    Animal models of intervertebral disc degeneration play an important role in clarifying the physiopathological mechanisms and testing novel therapeutic strategies. The objective of the present study is to describe a simple animal model of disc degeneration involving Wistar rats to be used for research studies. Disc degeneration was confirmed and classified by radiography, magnetic resonance and histological evaluation. Adult male Wistar rats were anesthetized and submitted to percutaneous disc puncture with a 20-gauge needle on levels 6-7 and 8-9 of the coccygeal vertebrae. The needle was inserted into the discs guided by fluoroscopy and its tip was positioned crossing the nucleus pulposus up to the contralateral annulus fibrosus, rotated 360° twice, and held for 30?s. To grade the severity of intervertebral disc degeneration, we measured the intervertebral disc height from radiographic images 7 and 30 days after the injury, and the signal intensity T2-weighted magnetic resonance imaging. Histological analysis was performed with hematoxylin-eosin and collagen fiber orientation using picrosirius red staining and polarized light microscopy. Imaging and histological score analyses revealed significant disc degeneration both 7 and 30 days after the lesion, without deaths or systemic complications. Interobserver histological evaluation showed significant agreement. There was a significant positive correlation between histological score and intervertebral disc height 7 and 30 days after the lesion. We conclude that the tail disc puncture method using Wistar rats is a simple, cost-effective and reproducible model for inducing disc degeneration. PMID:23532265

  17. Compressive strength of elderly vertebrae is reduced by disc degeneration and additional flexion.

    PubMed

    Maquer, Ghislain; Schwiedrzik, Jakob; Huber, Gerd; Morlock, Michael M; Zysset, Philippe K

    2015-02-01

    Computer tomography (CT)-based finite element (FE) models assess vertebral strength better than dual energy X-ray absorptiometry. Osteoporotic vertebrae are usually loaded via degenerated intervertebral discs (IVD) and potentially at higher risk under forward bending, but the influences of the IVD and loading conditions are generally overlooked. Accordingly, magnetic resonance imaging was performed on 14 lumbar discs to generate FE models for the healthiest and most degenerated specimens. Compression, torsion, bending, flexion and extension conducted experimentally were used to calibrate both models. They were combined with CT-based FE models of 12 lumbar vertebral bodies to evaluate the effect of disc degeneration compared to a loading via endplates embedded in a stiff resin, the usual experimental paradigm. Compression and lifting were simulated, load and damage pattern were evaluated at failure. Adding flexion to the compression (lifting) and higher disc degeneration reduces the failure load (8-14%, 5-7%) and increases damage in the vertebrae. Under both loading scenarios, decreasing the disc height slightly increases the failure load; embedding and degenerated IVD provides respectively the highest and lowest failure load. Embedded vertebrae are more brittle, but failure loads induced via IVDs correlate highly with vertebral strength. In conclusion, osteoporotic vertebrae with degenerated IVDs are consistently weaker-especially under lifting, but clinical assessment of their strength is possible via FE analysis without extensive disc modelling, by extrapolating measures from the embedded situation. PMID:25460926

  18. Identification of Degenerate Nuclei and Development of a SCAR Marker for Flammulina velutipes

    PubMed Central

    Kim, Sun Young; Kim, Kyung-Hee; Im, Chak Han; Ali, Asjad; Lee, Chang Yun; Kong, Won-Sik; Ryu, Jae-San

    2014-01-01

    Flammulina velutipes is one of the major edible mushrooms in the world. Recently, abnormalities that have a negative impact on crop production have been reported in this mushroom. These symptoms include slow vegetative growth, a compact mycelial mat, and few or even no fruiting bodies. The morphologies and fruiting capabilities of monokaryons of wild-type and degenerate strains that arose through arthrospore formation were investigated through test crossing. Only one monokaryotic group of the degenerate strains and its hybrid strains showed abnormal phenotypes. Because the monokaryotic arthrospore has the same nucleus as the parent strain, these results indicated that only one aberrant nucleus of the two nuclei in the degenerate strain was responsible for the degeneracy. A sequence-characterized amplified region marker that is linked to the degenerate monokaryon was identified based on a polymorphic sequence that was generated using random primers. Comparative analyses revealed the presence of a degenerate-specific genomic region in a telomere, which arose via the transfer of a genomic fragment harboring a putative helicase gene. Our findings have narrowed down the potential molecular targets responsible for this phenotype for future studies and have provided a marker for the detection of degenerate strains. PMID:25221949

  19. Linkage of Oxidative Stress and Mitochondrial Dysfunctions to Spontaneous Culture Degeneration in Aspergillus nidulans*

    PubMed Central

    Li, Lin; Hu, Xiao; Xia, Yongliang; Xiao, Guohua; Zheng, Peng; Wang, Chengshu

    2014-01-01

    Filamentous fungi including mushrooms frequently and spontaneously degenerate during subsequent culture maintenance on artificial media, which shows the loss or reduction abilities of asexual sporulation, sexuality, fruiting, and production of secondary metabolites, thus leading to economic losses during mass production. To better understand the underlying mechanisms of fungal degeneration, the model fungus Aspergillus nidulans was employed in this study for comprehensive analyses. First, linkage of oxidative stress to culture degeneration was evident in A. nidulans. Taken together with the verifications of cell biology and biochemical data, a comparative mitochondrial proteome analysis revealed that, unlike the healthy wild type, a spontaneous fluffy sector culture of A. nidulans demonstrated the characteristics of mitochondrial dysfunctions. Relative to the wild type, the features of cytochrome c release, calcium overload and up-regulation of apoptosis inducing factors evident in sector mitochondria suggested a linkage of fungal degeneration to cell apoptosis. However, the sector culture could still be maintained for generations without the signs of growth arrest. Up-regulation of the heat shock protein chaperones, anti-apoptotic factors and DNA repair proteins in the sector could account for the compromise in cell death. The results of this study not only shed new lights on the mechanisms of spontaneous degeneration of fungal cultures but will also provide alternative biomarkers to monitor fungal culture degeneration. PMID:24345786

  20. Photoreceptor Cell Apoptosis in the Retinal Degeneration of Uchl3-Deficient Mice

    PubMed Central

    Sano, Yae; Furuta, Akiko; Setsuie, Rieko; Kikuchi, Hisae; Wang, Yu-Lai; Sakurai, Mikako; Kwon, Jungkee; Noda, Mami; Wada, Keiji

    2006-01-01

    UCH-L3 belongs to the ubiquitin C-terminal hydrolase family that deubiquitinates ubiquitin-protein conjugates in the ubiquitin-proteasome system. A murine Uchl3 deletion mutant displays retinal degeneration, muscular degeneration, and mild growth retardation. To elucidate the function of UCH-L3, we investigated histopathological changes and expression of apoptosis- and oxidative stress-related proteins during retinal degeneration. In the normal retina, UCH-L3 was enriched in the photoreceptor inner segment that contains abundant mitochondria. Although the retina of Uchl3-deficient mice showed no significant morphological abnormalities during retinal development, prominent retinal degeneration became manifested after 3 weeks of age associated with photoreceptor cell apoptosis. Ultrastructurally, a decreased area of mitochondrial cristae and vacuolar changes were observed in the degenerated inner segment. Increased immunoreactivities for manganese superoxide dismutase, cytochrome c oxidase I, and apoptosis-inducing factor in the inner segment indicated mitochondrial oxidative stress. Expression of cytochrome c, caspase-1, and cleaved caspase-3 did not differ between wild-type and mutant mice; however, immunoreactivity for endonuclease G was found in the photoreceptor nuclei in the mutant retina. Hence, loss of UCH-L3 leads to mitochondrial oxidative stress-related photoreceptor cell apoptosis in a caspase-independent manner. Thus, Uchl3-deficient mice represent a model for adult-onset retinal degeneration associated with mitochondrial impairment. PMID:16816367

  1. Genome degeneration and adaptation in a nascent stage of symbiosis.

    PubMed

    Oakeson, Kelly F; Gil, Rosario; Clayton, Adam L; Dunn, Diane M; von Niederhausern, Andrew C; Hamil, Cindy; Aoyagi, Alex; Duval, Brett; Baca, Amanda; Silva, Francisco J; Vallier, Agnès; Jackson, D Grant; Latorre, Amparo; Weiss, Robert B; Heddi, Abdelaziz; Moya, Andrés; Dale, Colin

    2014-01-01

    Symbiotic associations between animals and microbes are ubiquitous in nature, with an estimated 15% of all insect species harboring intracellular bacterial symbionts. Most bacterial symbionts share many genomic features including small genomes, nucleotide composition bias, high coding density, and a paucity of mobile DNA, consistent with long-term host association. In this study, we focus on the early stages of genome degeneration in a recently derived insect-bacterial mutualistic intracellular association. We present the complete genome sequence and annotation of Sitophilus oryzae primary endosymbiont (SOPE). We also present the finished genome sequence and annotation of strain HS, a close free-living relative of SOPE and other insect symbionts of the Sodalis-allied clade, whose gene inventory is expected to closely resemble the putative ancestor of this group. Structural, functional, and evolutionary analyses indicate that SOPE has undergone extensive adaptation toward an insect-associated lifestyle in a very short time period. The genome of SOPE is large in size when compared with many ancient bacterial symbionts; however, almost half of the protein-coding genes in SOPE are pseudogenes. There is also evidence for relaxed selection on the remaining intact protein-coding genes. Comparative analyses of the whole-genome sequence of strain HS and SOPE highlight numerous genomic rearrangements, duplications, and deletions facilitated by a recent expansion of insertions sequence elements, some of which appear to have catalyzed adaptive changes. Functional metabolic predictions suggest that SOPE has lost the ability to synthesize several essential amino acids and vitamins. Analyses of the bacterial cell envelope and genes encoding secretion systems suggest that these structures and elements have become simplified in the transition to a mutualistic association. PMID:24407854

  2. OBSERVATIONAL CONSTRAINTS ON THE DEGENERATE MASS-RADIUS RELATION

    SciTech Connect

    Holberg, J. B. [Lunar and Planetary Laboratory, 1541 East University Boulevard, Sonett Space Sciences Building, University of Arizona, Tucson, AZ 85721 (United States); Oswalt, T. D. [Florida Institute of Technology, Melbourne, FL 32901 (United States); Barstow, M. A., E-mail: holberg@argus.lpl.arizona.edu, E-mail: toswalt@fit.edu, E-mail: mab@le.ac.uk [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)

    2012-03-15

    The white dwarf mass-radius relationship is fundamental to modern astrophysics. It is central to routine estimation of DA white dwarf masses derived from spectroscopic temperatures and gravities. It is also the basis for observational determinations of the white dwarf initial-final-mass relation. Nevertheless, definitive and detailed observational confirmations of the mass-radius relation (MRR) remain elusive owing to a lack of sufficiently accurate white dwarf masses and radii. Current best estimates of masses and radii allow only broad conclusions about the expected inverse relation between masses and radii in degenerate stars. In this paper, we examine a restricted set of 12 DA white dwarf binary systems for which accurate (1) trigonometric parallaxes, (2) spectroscopic effective temperatures and gravities, and (3) gravitational redshifts are available. We consider these three independent constraints on mass and radius in comparison with an appropriate evolved MRR for each star. For the best-determined systems it is found that the DA white dwarfs conform to evolve theoretical MRRs at the 1{sigma} to 2{sigma} level. For the white dwarf 40 Eri B (WD 0413-077) we find strong evidence for the existence of a 'thin' hydrogen envelope. For other stars improved parallaxes will be necessary before meaningful comparisons are possible. For several systems current parallaxes approach the precision required for the state-of-the-art mass and radius determinations that will be obtained routinely from the Gaia mission. It is demonstrated here how these anticipated results can be used to firmly constrain details of theoretical mass-radius determinations.

  3. Dopamine transporter: involvement in selective dopaminergic neurotoxicity and degeneration.

    PubMed

    Storch, A; Ludolph, A C; Schwarz, J

    2004-10-01

    The carrier molecule that transports dopamine (DA) into dopamine neurons by an electrogenic, Na(+)- and Cl(-)-transport-coupled mechanism is known as the dopamine transporter (DAT). This uptake system is exclusively expressed in DA neurons with significantly higher levels of DAT expression in cells of the substantia nigra pars compacta than those of the ventral tegmental area and arcuate hypothalamic neurons. The expression density of DAT strongly correlates with the extent of DA cell loss in Parkinson's disease (PD). There are also DAT gene polymorphisms associated with PD. These data suggest a role of the DAT in the pathogenesis of PD. Though selective for its respective neurotransmitter, the DAT can also transport synthetic/natural analogues of the transmitter. Should such compounds interact with vital intracellular structures, their penetration into the neuron might have significant consequences. This sequence of toxic events could indeed demonstrated for the synthetic toxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which produces selective degeneration of DA neurons characteristic of PD. Dopaminergic toxicity of its active metabolite 1-methyl-4-pyridinium (MPP(+)) is mediated by the DAT through accumulation into DA neurons, where it inhibits mitochondrial complex I activity. Various endogenous and exogenous heterocyclic molecules, which are structurally related to MPTP/MPP(+), such as isoquinolines and beta-carbolines, have been reported to exhibit similar toxic properties on DA cells, which are conferred by their uptake by the DAT. Taken together, there is large body of evidence from morphological, molecular biological and toxicological studies indicating that the DAT might be responsible for the selectivity of DA cell death in PD. PMID:15480838

  4. ["Forced mouth opening reaction" associated with corticobasal degeneration].

    PubMed

    Ohkawa, S; Yamasaki, H; Yoshida, T; Ohsumi, Y; Tabuchi, M

    1997-04-01

    Corticobasal degeneration (CBD) is a slowly progressive disorder characterized by an asymmetrical akinetic-rigid syndrome, supranuclear ophthalmoplegia, dystonia, often accompanied by involuntary movements, particularly myoclonus, and associated with lateralized cortical signs such as alien limb behavior and apraxia. Computerized tomography demonstrates asymmetrical frontoparietal cortical atrophy in the later stages of the illness. Neuropathological examination reveals neuronal loss, gliosis and swollen achromatic neurons within the frontal and temporal cortices, and the substantia nigra. We discuss here a unique phenomenon not described so far in three patients with clinical features of CBD, one with subsequent autopsy observations. When awake, they all showed a common behavior, their mouth opened constantly and immediately, when a tongue-depresser was approached in front of it by the examiner. In two of them, their mouth also opened when its corner was stroked by a tongue-depressor. They could not control these phenomena at all, even they were asked not to open their mouth. We would like to call these phenomena "forced mouth opening reactions" because they were uncontrollable voluntarily. They may be divided into two groups, i.e. visual and tactile "forced mouth opening reactions". In all the patients the neurological, neuro-imaging and neuropathological data showed that the frontal lobes were damaged. Additionally, they had some frontal lobe release signs such as forced grasping, forced groping, or alien limb sign. We would like to apply the mechanism for these release signs to the "forced mouth opening reactions". Thus, we speculate that the frontal lobe contains a higher motor control mechanism for normal mouth opening movement, and the "forced mouth opening reactions" result from impairment of this control. PMID:9248334

  5. Genome Degeneration and Adaptation in a Nascent Stage of Symbiosis

    PubMed Central

    Oakeson, Kelly F.; Gil, Rosario; Clayton, Adam L.; Dunn, Diane M.; von Niederhausern, Andrew C.; Hamil, Cindy; Aoyagi, Alex; Duval, Brett; Baca, Amanda; Silva, Francisco J.; Vallier, Agnès; Jackson, D. Grant; Latorre, Amparo; Weiss, Robert B.; Heddi, Abdelaziz; Moya, Andrés; Dale, Colin

    2014-01-01

    Symbiotic associations between animals and microbes are ubiquitous in nature, with an estimated 15% of all insect species harboring intracellular bacterial symbionts. Most bacterial symbionts share many genomic features including small genomes, nucleotide composition bias, high coding density, and a paucity of mobile DNA, consistent with long-term host association. In this study, we focus on the early stages of genome degeneration in a recently derived insect-bacterial mutualistic intracellular association. We present the complete genome sequence and annotation of Sitophilus oryzae primary endosymbiont (SOPE). We also present the finished genome sequence and annotation of strain HS, a close free-living relative of SOPE and other insect symbionts of the Sodalis-allied clade, whose gene inventory is expected to closely resemble the putative ancestor of this group. Structural, functional, and evolutionary analyses indicate that SOPE has undergone extensive adaptation toward an insect-associated lifestyle in a very short time period. The genome of SOPE is large in size when compared with many ancient bacterial symbionts; however, almost half of the protein-coding genes in SOPE are pseudogenes. There is also evidence for relaxed selection on the remaining intact protein-coding genes. Comparative analyses of the whole-genome sequence of strain HS and SOPE highlight numerous genomic rearrangements, duplications, and deletions facilitated by a recent expansion of insertions sequence elements, some of which appear to have catalyzed adaptive changes. Functional metabolic predictions suggest that SOPE has lost the ability to synthesize several essential amino acids and vitamins. Analyses of the bacterial cell envelope and genes encoding secretion systems suggest that these structures and elements have become simplified in the transition to a mutualistic association. PMID:24407854

  6. Hsp90 inhibition protects against inherited retinal degeneration

    PubMed Central

    Aguilà, Mònica; Bevilacqua, Dalila; McCulley, Caroline; Schwarz, Nele; Athanasiou, Dimitra; Kanuga, Naheed; Novoselov, Sergey S.; Lange, Clemens A.K.; Ali, Robin R.; Bainbridge, James W.; Gias, Carlos; Coffey, Peter J.; Garriga, Pere; Cheetham, Michael E.

    2014-01-01

    The molecular chaperone Hsp90 is important for the functional maturation of many client proteins, and inhibitors are in clinical trials for multiple indications in cancer. Hsp90 inhibition activates the heat shock response and can improve viability in a cell model of the P23H misfolding mutation in rhodopsin that causes autosomal dominant retinitis pigmentosa (adRP). Here, we show that a single low dose of the Hsp90 inhibitor HSP990 enhanced visual function and delayed photoreceptor degeneration in a P23H transgenic rat model. This was associated with the induction of heat shock protein expression and reduced rhodopsin aggregation. We then investigated the effect of Hsp90 inhibition on a different type of rod opsin mutant, R135L, which is hyperphosphorylated, binds arrestin and disrupts vesicular traffic. Hsp90 inhibition with 17-AAG reduced the intracellular accumulation of R135L and abolished arrestin binding in cells. Hsf-1?/? cells revealed that the effect of 17-AAG on P23H aggregation was dependent on HSF-1, whereas the effect on R135L was HSF-1 independent. Instead, the effect on R135L was mediated by a requirement of Hsp90 for rhodopsin kinase (GRK1) maturation and function. Importantly, Hsp90 inhibition restored R135L rod opsin localization to wild-type (WT) phenotype in vivo in rat retina. Prolonged Hsp90 inhibition with HSP990 in vivo led to a posttranslational reduction in GRK1 and phosphodiesterase (PDE6) protein levels, identifying them as Hsp90 clients. These data suggest that Hsp90 represents a potential therapeutic target for different types of rhodopsin adRP through distinct mechanisms, but also indicate that sustained Hsp90 inhibition might adversely affect visual function. PMID:24301679

  7. Nitrated ?–Synuclein Immunity Accelerates Degeneration of Nigral Dopaminergic Neurons

    PubMed Central

    Reynolds, Ashley D.; Sherman, Simon; Pisarev, Vladimir M.; Tsiperson, Vladislav; Nemachek, Craig; Ciborowski, Pawel; Przedborski, Serge; Mosley, R. Lee; Gendelman, Howard E.

    2008-01-01

    Background The neuropathology of Parkinson's disease (PD) includes loss of dopaminergic neurons in the substantia nigra, nitrated ?-synuclein (N-?-Syn) enriched intraneuronal inclusions or Lewy bodies and neuroinflammation. While the contribution of innate microglial inflammatory activities to disease are known, evidence for how adaptive immune mechanisms may affect the course of PD remains obscure. We reasoned that PD-associated oxidative protein modifications create novel antigenic epitopes capable of peripheral adaptive T cell responses that could affect nigrostriatal degeneration. Methods and Findings Nitrotyrosine (NT)-modified ?-Syn was detected readily in cervical lymph nodes (CLN) from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxicated mice. Antigen-presenting cells within the CLN showed increased surface expression of major histocompatibility complex class II, initiating the molecular machinery necessary for efficient antigen presentation. MPTP-treated mice produced antibodies to native and nitrated ?-Syn. Mice immunized with the NT-modified C-terminal tail fragment of ?-Syn, but not native protein, generated robust T cell proliferative and pro-inflammatory secretory responses specific only for the modified antigen. T cells generated against the nitrated epitope do not respond to the unmodified protein. Mice deficient in T and B lymphocytes were resistant to MPTP-induced neurodegeneration. Transfer of T cells from mice immunized with N-?-Syn led to a robust neuroinflammatory response with accelerated dopaminergic cell loss. Conclusions These data show that NT modifications within ?-Syn, can bypass or break immunological tolerance and activate peripheral leukocytes in draining lymphoid tissue. A novel mechanism for disease is made in that NT modifications in ?-Syn induce adaptive immune responses that exacerbate PD pathobiology. These results have implications for both the pathogenesis and treatment of this disabling neurodegenerative disease. PMID:18167537

  8. Visual cortex organisation in a macaque monkey with macular degeneration.

    PubMed

    Shao, Yibin; Keliris, Georgios A; Papanikolaou, Amalia; Fischer, M Dominik; Zobor, Ditta; Jägle, Herbert; Logothetis, Nikos K; Smirnakis, Stelios M

    2013-11-01

    The visual field is retinotopically represented in early visual areas. It has been suggested that when adult primary visual cortex (V1) is deprived of normal retinal input it is capable of large-scale reorganisation, with neurons inside the lesion projection zone (LPZ) being visually driven by inputs from intact retinal regions. Early functional magnetic resonance imaging (fMRI) studies in humans with macular degeneration (MD) report > 1 cm spread of activity inside the LPZ border, whereas recent results report no shift of the LPZ border. Here, we used fMRI population receptive field measurements to study, for the first time, the visual cortex organisation of one macaque monkey with MD and to compare it with normal controls. Our results showed that the border of the V1 LPZ remained stable, suggesting that the deafferented area V1 zone of the MD animal has limited capacity for reorganisation. Interestingly, the pRF size of non-deafferented V1 voxels increased slightly (~20% on average), although this effect appears weaker than that in previous single-unit recording reports. Area V2 also showed limited reorganisation. Remarkably, area V5/MT of the MD animal showed extensive activation compared to controls stimulated over the part of the visual field that was spared in the MD animal. Furthermore, population receptive field size distributions differed markedly in area V5/MT of the MD animal. Taken together, these results suggest that V5/MT has a higher potential for reorganisation after MD than earlier visual cortex. PMID:24033706

  9. Neurocognitive speed associates with frontotemporal lobar degeneration TDP-43 subtypes

    PubMed Central

    Dean, Pamela M.; Smith, Glenn E.; Parisi, Joseph E.; Dickson, Dennis W.; Petersen, Ronald C.; Josephs, Keith A.

    2013-01-01

    Frontotemporal lobar degeneration (FTLD) is pathologically heterogeneous with TAR DNA binding protein 43 kDa (TDP-43) proteinopathy the most common substrate. Previous work has identified atrophy patterns across TDP-43 subtypes with Type A showing greater frontotemporal and parietal atrophy, Type C predominantly anterior temporal, and Type B predominantly posterior frontal. Despite neuroanatomical correlates of involvement, neuropsychological findings have been inconsistent. The current study utilized broader neurocognitive domains based on aggregated neuropsychological measures to distinguish between subtypes. We hypothesized that patterns of neurocognitive domain impairments would predict FTLD–TDP-43 subtype. Fifty-one patients, aged 38–87, were identified post mortem with pathologically confirmed FTLD with TDP-43. Participants were classified into subtypes A, B, or C. Patients had completed neuropsychological assessments as part of their clinical evaluation. Six cognitive domains were created: Language; Cognitive Speed; Memory; Learning; Visuoperception; and Fluency. Binary logistic regression was conducted. All but three patients could be classified as FTLD–TDP Types A, B, or C: 26 as Type A; nine as Type B; and 13 as Type C. Cognitive Speed scores were associated with Types A and C (p < 0.001 and p = 0.003, respectively). Impaired performances on the Trail Making Test differentiated Types A and C. Worse Boston Naming Test and Logical Memory (Immediate) (p < 0.05) scores also increased the likelihood of Type C phenotype. Findings suggest Cognitive Speed associates with TDP-43 subtypes. Type C also demonstrated language-specific involvement. Differences between TDP-43 subtypes further supports the notion of differences in pathophysiology or topography across these types. PMID:24012243

  10. VAGINAL DEGENERATION FOLLOWING IMPLANTATION OF SYNTHETIC MESH WITH INCREASED STIFFNESS

    PubMed Central

    Liang, Rui; Abramowitch, Steven; Knight, Katrina; Palcsey, Stacy; Nolfi, Alexis; Feola, Andrew; Stein, Susan; Moalli, Pamela A.

    2012-01-01

    Objective To compare the impact of the prototype prolapse mesh Gynemesh PS to that of two new generation lower stiffness meshes, UltraPro and SmartMesh, on vaginal morphology and structural composition. Design A mechanistic study employing a non-human primate (NHP) model. Setting Magee-Womens Research Institute at the University of Pittsburgh. Population Parous rhesus macaques, with similar age, weight, parity and POP-Q scores. Methods Following IACUC approval, 50 rhesus macaques were implanted with Gynemesh PS (n=12), UltraPro with its blue line perpendicular to the longitudinal axis of vagina (n=10), UltraPro with its blue line parallel to the longitudinal axis of vagina (n=8) and SmartMesh (n=8) via sacrocolpopexy following hysterectomy. Sham operated animals (n=12) served as controls. Main Outcome Measures The mesh-vagina complex (MVC) was removed after 12 weeks and analyzed for histomorphology, in situ cell apoptosis, total collagen, elastin, glycosaminoglycan content and total collagenase activity. Appropriate statistics and correlation analyses were performed accordingly. Results Relative to sham and the two lower stiffness meshes, Gynemesh PS had the greatest negative impact on vaginal histomorphology and composition. Compared to sham, implantation with Gynemesh PS caused substantial thinning of the smooth muscle layer (1557 ± 499?m vs 866 ± 210 ?m, P=0.02), increased apoptosis particularly in the area of the mesh fibers (P=0.01), decreased collagen and elastin content (20% (P=0.03) and 43% (P=0.02), respectively) and increased total collagenase activity (135% (P=0.01)). GAG (glycosaminoglycan), a marker of tissue injury, was the highest with Gynemesh PS compared to sham and other meshes (P=0.01). Conclusion Mesh implantation with the stiffer mesh Gynemesh PS induced a maladaptive remodeling response consistent with vaginal degeneration. PMID:23240802

  11. Genetic risk factors and age-related macular degeneration (AMD)

    PubMed Central

    Mousavi, Maryam; Armstrong, Richard A.

    2013-01-01

    Age related macular degeneration (AMD) is the leading cause of blindness in individuals older than 65 years of age. It is a multifactorial disorder and identification of risk factors enables individuals to make lifestyle choices that may reduce the risk of disease. Collaboration between geneticists, ophthalmologists, and optometrists suggests that genetic risk factors play a more significant role in AMD than previously thought. The most important genes are associated with immune system modulation and the complement system, e.g., complement factor H (CFH), factor B (CFB), factor C3, and serpin peptidase inhibitor (SERPING1). Genes associated with membrane transport, e.g., ATP-binding cassette protein (ABCR) and voltage-dependent calcium channel gamma 3 (CACNG3), the vascular system, e.g., fibroblast growth factor 2 (FGF2), fibulin-5, lysyl oxidase-like gene (LOXL1) and selectin-P (SELP), and with lipid metabolism, e.g., apolipoprotein E (APOE) and hepatic lipase (LIPC) have also been implicated. In addition, several other genes exhibit some statistical association with AMD, e.g., age-related maculopathy susceptibility protein 2 (ARMS2) and DNA excision repair protein gene (ERCC6) but more research is needed to establish their significance. Modifiable risk factors for AMD should be discussed with patients whose lifestyle and/or family history place them in an increased risk category. Furthermore, calculation of AMD risk using current models should be recommended as a tool for patient education. It is likely that AMD management in future will be increasingly influenced by assessment of genetic risk as such screening methods become more widely available.

  12. Hsp90 inhibition protects against inherited retinal degeneration.

    PubMed

    Aguilà, Mònica; Bevilacqua, Dalila; McCulley, Caroline; Schwarz, Nele; Athanasiou, Dimitra; Kanuga, Naheed; Novoselov, Sergey S; Lange, Clemens A K; Ali, Robin R; Bainbridge, James W; Gias, Carlos; Coffey, Peter J; Garriga, Pere; Cheetham, Michael E

    2014-04-15

    The molecular chaperone Hsp90 is important for the functional maturation of many client proteins, and inhibitors are in clinical trials for multiple indications in cancer. Hsp90 inhibition activates the heat shock response and can improve viability in a cell model of the P23H misfolding mutation in rhodopsin that causes autosomal dominant retinitis pigmentosa (adRP). Here, we show that a single low dose of the Hsp90 inhibitor HSP990 enhanced visual function and delayed photoreceptor degeneration in a P23H transgenic rat model. This was associated with the induction of heat shock protein expression and reduced rhodopsin aggregation. We then investigated the effect of Hsp90 inhibition on a different type of rod opsin mutant, R135L, which is hyperphosphorylated, binds arrestin and disrupts vesicular traffic. Hsp90 inhibition with 17-AAG reduced the intracellular accumulation of R135L and abolished arrestin binding in cells. Hsf-1(-/-) cells revealed that the effect of 17-AAG on P23H aggregation was dependent on HSF-1, whereas the effect on R135L was HSF-1 independent. Instead, the effect on R135L was mediated by a requirement of Hsp90 for rhodopsin kinase (GRK1) maturation and function. Importantly, Hsp90 inhibition restored R135L rod opsin localization to wild-type (WT) phenotype in vivo in rat retina. Prolonged Hsp90 inhibition with HSP990 in vivo led to a posttranslational reduction in GRK1 and phosphodiesterase (PDE6) protein levels, identifying them as Hsp90 clients. These data suggest that Hsp90 represents a potential therapeutic target for different types of rhodopsin adRP through distinct mechanisms, but also indicate that sustained Hsp90 inhibition might adversely affect visual function. PMID:24301679

  13. Magnetotransport in epitaxial films of the degenerate semiconductor Zn(1-x)Co(x)O.

    PubMed

    Budhani, R C; Pant, Prita; Rakshit, R K; Senapati, K; Mandal, S; Pandey, N K; Jitendra Kumar

    2005-01-12

    Magnetotransport measurements are performed over a broad range of temperature (T) and magnetic field (H) on highly degenerate n-type Zn(1-x)Co(x)O [Formula: see text] epitaxial films. The cobalt-free samples are characterized by a metallic resistivity ?(T) down to 2 K, a negative and predominantly isotropic magnetoresistance (MR) and optical transmission above 85% in the visible range of the electromagnetic spectrum. X-ray diffraction measurements show that while for [Formula: see text], all cobalt atoms occupy the tetrahedral sites of the wurtzite structure of ZnO, a phase separation into CoO is seen for x>0.2. In the solution phase, we do not observe any signatures of a spontaneous ordering of the cobalt spins despite a large concentration of mobile electrons (>10(20) cm(-3)). The absence of anomalous Hall resistance is consistent with this observation. The carrier concentration (n) over the entire range of x remains above the Mott limit for the insulator-to-metal transition in a doped semiconductor. However, while the Co-free samples are metallic (T>2 K), we see a resistivity (?) minimum followed by lnT divergence of ?(T) at low temperatures with increasing x. The magnetoresistance of these samples is negative and predominantly isotropic. Moreover, the MR tends to follow a logH behaviour at high fields. These observations, including the Kondo-like minimum in the resistivity, suggest s-d exchange dominated transport in these dilute magnetic semiconductors. PMID:21690670

  14. Prevalence and pattern of radiographic intervertebral disc degeneration in vietnamese: a population-based study.

    PubMed

    Ho-Pham, Lan T; Lai, Thai Q; Mai, Linh D; Doan, Minh C; Pham, Hoa N; Nguyen, Tuan V

    2015-06-01

    Intervertebral disc degeneration (IDD) is one of the most common skeletal disorders, yet few data are available in Asian populations. We sought to assess the prevalence and pattern of radiographic IDD in a Vietnamese population. This population-based cross-sectional investigation involved 170 men and 488 women aged ?40 years, who were randomly sampled from the Ho Chi Minh City (Vietnam). Anthropometric data, clinical history and self-reported back and neck pain were ascertained by a questionnaire. Plain radiographs (from the cervical spine, thoracic spine to the lumbar spine) were examined for the presence of disc space narrowing and/or osteophytosis using the Kellgren-Lawrence (KL) grading system. The presence of radiographic IDD was defined if the KL grade was 2 or greater in at least one disc. The prevalence of radiographic IDD was 62.4 % (n = 106) in men and 54.7 % (n = 267) in women. The most frequently affected site was the lumbar spine with prevalence being 50.6 and 43.2 % in men and women, respectively. The prevalence of IDD increased with advancing age: 18.8 % among those aged 40-49 years, and increased to 83.4 % in those aged ?60 years. Self-reported neck pain and lower back pain were found in 30 and 44 % of individuals, respectively. There was no statistically significant association between self-reported neck pain and cervical spine OA. These data suggest that radiographic IDD is highly prevalent in the Vietnamese population, and that self-reported back pain is not a sensitive indicator of IDD. PMID:25791571

  15. Regulation of age-related macular degeneration-like pathology by complement factor H

    PubMed Central

    Toomey, Christopher B.; Kelly, Una; Saban, Daniel R.; Bowes Rickman, Catherine

    2015-01-01

    Complement factor H (CFH) is a major susceptibility gene for age-related macular degeneration (AMD); however, its impact on AMD pathobiology is unresolved. Here, the role of CFH in the development of AMD pathology in vivo was interrogated by analyzing aged Cfh+/? and Cfh?/? mice fed a high-fat, cholesterol-enriched diet. Strikingly, decreased levels of CFH led to increased sub-retinal pigmented epithelium (sub-RPE) deposit formation, specifically basal laminar deposits, following high-fat diet. Mechanistically, our data show that deposits are due to CFH competition for lipoprotein binding sites in Bruch’s membrane. Interestingly and despite sub-RPE deposit formation occurring in both Cfh+/? and Cfh?/? mice, RPE damage accompanied by loss of vision occurred only in old Cfh+/? mice. We demonstrate that such pathology is a function of excess complement activation in Cfh+/? mice versus complement deficiency in Cfh?/? animals. Due to the CFH-dependent increase in sub-RPE deposit height, we interrogated the potential of CFH as a previously unidentified regulator of Bruch’s membrane lipoprotein binding and show, using human Bruch’s membrane explants, that CFH removes endogenous human lipoproteins in aged donors. Thus, advanced age, high-fat diet, and decreased CFH induce sub-RPE deposit formation leading to complement activation, which contributes to RPE damage and visual function impairment. This new understanding of the complicated interactions of CFH in AMD-like pathology provides an improved foundation for the development of targeted therapies for AMD. PMID:25991857

  16. Novel Degenerate PCR Method for Whole-Genome Amplification Applied to Peru Margin (ODP Leg 201) Subsurface Samples

    PubMed Central

    Martino, Amanda J.; Rhodes, Matthew E.; Biddle, Jennifer F.; Brandt, Leah D.; Tomsho, Lynn P.; House, Christopher H.

    2011-01-01

    A degenerate polymerase chain reaction (PCR)-based method of whole-genome amplification, designed to work fluidly with 454 sequencing technology, was developed and tested for use on deep marine subsurface DNA samples. While optimized here for use with Roche 454 technology, the general framework presented may be applicable to other next generation sequencing systems as well (e.g., Illumina, Ion Torrent). The method, which we have called random amplification metagenomic PCR (RAMP), involves the use of specific primers from Roche 454 amplicon sequencing, modified by the addition of a degenerate region at the 3? end. It utilizes a PCR reaction, which resulted in no amplification from blanks, even after 50 cycles of PCR. After efforts to optimize experimental conditions, the method was tested with DNA extracted from cultured E. coli cells, and genome coverage was estimated after sequencing on three different occasions. Coverage did not vary greatly with the different experimental conditions tested, and was around 62% with a sequencing effort equivalent to a theoretical genome coverage of 14.10×. The GC content of the sequenced amplification product was within 2% of the predicted values for this strain of E. coli. The method was also applied to DNA extracted from marine subsurface samples from ODP Leg 201 site 1229 (Peru Margin), and results of a taxonomic analysis revealed microbial communities dominated by Proteobacteria, Chloroflexi, Firmicutes, Euryarchaeota, and Crenarchaeota, among others. These results were similar to those obtained previously for those samples; however, variations in the proportions of taxa identified illustrates well the generally accepted view that community analysis is sensitive to both the amplification technique used and the method of assigning sequences to taxonomic groups. Overall, we find that RAMP represents a valid methodology for amplifying metagenomes from low-biomass samples. PMID:22319519

  17. Transcriptional regulation of bone morphogenetic protein 4 by tumor necrosis factor and its relationship with age-related macular degeneration

    PubMed Central

    Xu, Jing; Zhu, Danhong; He, Shikun; Spee, Christine; Ryan, Stephen J.; Hinton, David R.

    2011-01-01

    Bone morphogenetic protein-4 (BMP4) may be involved in the molecular switch that determines which late form of age-related macular degeneration (AMD) an individual develops. BMP4 expression is high in retinal pigment epithelium (RPE) cells in late, dry AMD patients, while BMP4 expression is low in the wet form of the disease, characterized by choroidal neovascularization (CNV). Here, we sought to determine the mechanism by which BMP4 is down-regulated in CNV. BMP4 expression was decreased within laser-induced CNV lesions in mice at a time when tumor necrosis factor (TNF) expression was high (7 d postlaser) and was reexpressed in RPE when TNF levels declined (14 d postlaser). We found that TNF, an important angiogenic stimulus, significantly down-regulates BMP4 expression in cultured human fetal RPE cells, ARPE-19 cells, and RPE cells in murine posterior eye cup explants. We identified two specificity protein 1 (Sp1) binding sites in the BMP4 promoter that are required for basal expression of BMP4 and its down-regulation by TNF. Through c-Jun NH2-terminal kinase (JNK) activation, TNF modulates Sp1 phosphorylation, thus decreasing its affinity to the BMP4 promoter. The down-regulation of BMP4 expression by TNF in CNV and mechanisms established might be useful for defining novel targets for AMD therapy.—Xu, J., Zhu, D., He, S., Spee, C., Ryan, S. J., Hinton, D. R. Transcriptional regulation of bone morphogenetic protein 4 by tumor necrosis factor and its relationship with age-related macular degeneration. PMID:21411747

  18. Degenerate MAGGY elements in a subgroup of Pyricularia grisea: a possible example of successful capture of a genetic invader by a fungal genome.

    PubMed

    Nakayashiki, H; Nishimoto, N; Ikeda, K; Tosa, Y; Mayama, S

    1999-07-01

    The LTR-retrotransposon MAGGY is found sporadically in isolates of Pyricularia grisea (Magnaporthe grisea). Based on a dendrogram constructed by RFLP analysis of rDNA, isolates that carry MAGGY elements were classified into a single cluster that comprised four rDNA types. However, in a few members of this cluster, exemplified by isolates from common millet (Panicum miliaceum), the MAGGY element has distinct features. Southern analysis suggested that these isolates possessed a single copy of a MAGGY-related sequence whose restriction map differed from that of MAGGY itself. Sequence analysis revealed that the MAGGY-related sequence was a degenerate form of MAGGY, characterized by numerous C:G to T:A transitions, which have often been reported to result from RIP (Repeat-induced point mutation) or RIP-like processes. However, the favored target site for C:G to T:A transitions in this fungus, determined by examining a total of 501 sites, was (A/T)pCp(A/T), which differs from that for the RIP process originally reported in Neurospora (CpA), and from that reported in Aspergillus (CpG). The fact that certain members of the cluster of MAGGY carriers retain a single copy of a degenerate MAGGY element implies that the ancestor of these isolates successfully "captured" the invading MAGGY element. PMID:10485287

  19. Effect of Lycium barbarum (Wolfberry) on alleviating axonal degeneration after partial optic nerve transection.

    PubMed

    Li, Hong-Ying; Ruan, Yi-Wen; Kau, Phillis Wan-Foon; Chiu, Kin; Chang, Raymond Chuen-Chung; Chan, Henry H L; So, Kwok-Fai

    2015-01-01

    Our previous results showed that the polysaccharides extracted from Lycium barbarum (LBP) could delay secondary degeneration of retinal ganglion cell bodies and improve the function of the retinas after partial optic nerve transection (PONT). Although the common degeneration mechanisms were believed to be shared by both neuronal bodies and axons, recently published data from slow Wallerian degeneration mutant (Wld(s)) mice supported the divergence in the mechanisms of them. Therefore, we want to determine if LBP could also delay the degeneration of axons after PONT. Microglia/macrophages were thought to be a source of reactive oxygen species after central nervous system (CNS) injury. After PONT, however, oxidative stress was believed to occur prior to the activation of microglia/macrophages in the areas vulnerable to secondary degeneration both in the optic nerves (ONs) and the retinas. But the results did not take into account the morphological changes of microglia/macrophages after their activation. So we examined the morphology in addition to the response magnitude of microglia/macrophages to determine their time point of activation. In addition, the effects of LBP on the activation of microglia/macrophages were investigated. The results showed that (1) LBP reduced the loss of axons in the central ONs and preserved the g-ratio (axon diameter/fiber diameter) in the ventral ONs although no significant effect was detected in the dorsal ONs; (2) microglia/macrophages were activated in the ONs by 12 h after PONT; (3) LBP decreased the response magnitude of microglia/macrophages 4 weeks after PONT. In conclusion, our results showed that LBP could delay secondary degeneration of the axons, and LBP could also inhibit the activation of microglia/macrophages. Therefore, LBP could be a promising herbal medicine to delay secondary degeneration in the CNS via modulating the function of microglia/macrophages. PMID:25622224

  20. Regenerative effects of transplanting mesenchymal stem cells embedded in atelocollagen to the degenerated intervertebral disc.

    PubMed

    Sakai, Daisuke; Mochida, Joji; Iwashina, Toru; Hiyama, Akihiko; Omi, Hiroko; Imai, Masaaki; Nakai, Tomoko; Ando, Kiyoshi; Hotta, Tomomitsu

    2006-01-01

    Intervertebral disc (IVD) degeneration, a common cause of low back pain in humans, is a relentlessly progressive phenomenon with no currently available effective treatment. In an attempt to solve this dilemma, we transplanted autologous mesenchymal stem cells (MSCs) from bone marrow into a rabbit model of disc degeneration to determine if stem cells could repair degenerated IVDs. LacZ expressing MSCs were transplanted to rabbit L2-L3, L3-L4 and L4-L5 IVDs 2 weeks after induction of degeneration. Changes in disc height by plain radiograph, T2-weighted signal intensity in magnetic resonance imaging (MRI), histology, immunohistochemistry and matrix associated gene expressions were evaluated between normal controls (NC) without operations, sham operated with only disc degeneration being induced, and MSC-transplanted animals for a 24-week period. Results showed that after 24 weeks post-MSC transplantation, degenerated discs of MSC-transplanted group animals regained a disc height value of about 91%, MRI signal intensity of about 81%, compared to NC group discs. On the other hand, sham-operated group discs demonstrated the disc height value of about 67% and MRI signal intensity of about 60%. Macroscopic and histological evaluations confirmed relatively preserved nucleus with circular annulus structure in MSC-transplanted discs compared to indistinct structure seen in sham. Restoration of proteoglycan accumulation in MSC-transplanted discs was suggested from immunohistochemistry and gene expression analysis. These data indicate that transplantation of MSCs effectively led to regeneration of IVDs in a rabbit model of disc degeneration as suggested in our previous pilot study. MSCs may serve as a valuable resource in cell transplantation therapy for degenerative disc disease. PMID:16112726

  1. Progressive ganglion cell degeneration precedes neuronal loss in a mouse model of glaucoma.

    PubMed

    Buckingham, Brian P; Inman, Denise M; Lambert, Wendi; Oglesby, Ericka; Calkins, David J; Steele, Michael R; Vetter, Monica L; Marsh-Armstrong, Nicholas; Horner, Philip J

    2008-03-12

    Glaucoma is characterized by retinal ganglion cell (RGC) pathology and a progressive loss of vision. Previous studies suggest RGC death is responsible for vision loss in glaucoma, yet evidence from other neurodegenerative diseases suggests axonal degeneration, in the absence of neuronal loss, can significantly affect neuronal function. To characterize RGC degeneration in the DBA/2 mouse model of glaucoma, we quantified RGCs in mice of various ages using neuronal-specific nuclear protein (NeuN) immunolabeling, retrograde labeling, and optic nerve axon counts. Surprisingly, the number of NeuN-labeled RGCs did not decline significantly until 18 months of age, at which time a significant decrease in RGC somal size was also observed. Axon dysfunction and degeneration occurred before loss of NeuN-positive RGCs, because significant declines in RGC number assayed by retrograde tracers and axon counts were observed at 13 months. To examine whether axonal dysfunction/degeneration affected gene expression in RGC axons or somas, NeuN and neurofilament-heavy (NF-H) immunolabeling was performed along with quantitative reverse transcription-PCR for RGC-specific genes in retinas of aged DBA/2 mice. Although these mice had similar numbers of NeuN-positive RGCs, the expression of neurofilament light, Brn-3b, and Sncg mRNA varied; this variation in RGC-specific gene expression was correlated with the appearance of NF-H immunoreactive RGC axons. Together, these data support a progression of RGC degeneration in this model of glaucoma, beginning with loss of retrograde label, where axon dysfunction and degeneration precede neuronal loss. This progression of degeneration suggests a need to examine the RGC axon as a locus of pathology in glaucoma. PMID:18337403

  2. Progress on retinal image analysis for age related macular degeneration.

    PubMed

    Kanagasingam, Yogesan; Bhuiyan, Alauddin; Abràmoff, Michael D; Smith, R Theodore; Goldschmidt, Leonard; Wong, Tien Y

    2014-01-01

    Age-related macular degeneration (AMD) is the leading cause of vision loss in those over the age of 50 years in the developed countries. The number is expected to increase by ?1.5 fold over the next ten years due to an increase in aging population. One of the main measures of AMD severity is the analysis of drusen, pigmentary abnormalities, geographic atrophy (GA) and choroidal neovascularization (CNV) from imaging based on color fundus photograph, optical coherence tomography (OCT) and other imaging modalities. Each of these imaging modalities has strengths and weaknesses for extracting individual AMD pathology and different imaging techniques are used in combination for capturing and/or quantification of different pathologies. Current dry AMD treatments cannot cure or reverse vision loss. However, the Age-Related Eye Disease Study (AREDS) showed that specific anti-oxidant vitamin supplementation reduces the risk of progression from intermediate stages (defined as the presence of either many medium-sized drusen or one or more large drusen) to late AMD which allows for preventative strategies in properly identified patients. Thus identification of people with early stage AMD is important to design and implement preventative strategies for late AMD, and determine their cost-effectiveness. A mass screening facility with teleophthalmology or telemedicine in combination with computer-aided analysis for large rural-based communities may identify more individuals suitable for early stage AMD prevention. In this review, we discuss different imaging modalities that are currently being considered or used for screening AMD. In addition, we look into various automated and semi-automated computer-aided grading systems and related retinal image analysis techniques for drusen, geographic atrophy and choroidal neovascularization detection and/or quantification for measurement of AMD severity using these imaging modalities. We also review the existing telemedicine studies which include diagnosis and management of AMD, and how automated disease grading could benefit telemedicine. As there is no treatment for dry AMD and only early intervention can prevent the late AMD, we emphasize mass screening through a telemedicine platform to enable early detection of AMD. We also provide a comparative study between the imaging modalities and identify potential study areas for further improvement and future research direction in automated AMD grading and screening. PMID:24211245

  3. The ERCC6 Gene and Age-Related Macular Degeneration

    PubMed Central

    Bergeron-Sawitzke, Julie; Uitterlinden, André G.; Hofman, Albert; van Duijn, Cornelia M.; Merriam, Joanna E.; Smith, R. Theodore; Barile, Gaetano R.; ten Brink, Jacoline B.; Vingerling, Johannes R.; Klaver, Caroline C. W.; Allikmets, Rando; Dean, Michael; Bergen, Arthur A. B.

    2010-01-01

    Background Age-related macular degeneration (AMD) is the leading cause of irreversible visual loss in the developed countries and is caused by both environmental and genetic factors. A recent study (Tuo et al., PNAS) reported an association between AMD and a single nucleotide polymorphism (SNP) (rs3793784) in the ERCC6 (NM_000124) gene. The risk allele also increased ERCC6 expression. ERCC6 is involved in DNA repair and mutations in ERCC6 cause Cockayne syndrome (CS). Amongst others, photosensitivity and pigmentary retinopathy are hallmarks of CS. Methodology/Principal Findings Separate and combined data from three large AMD case-control studies and a prospective population-based study (The Rotterdam Study) were used to analyse the genetic association between ERCC6 and AMD (2682 AMD cases and 3152 controls). We also measured ERCC6 mRNA levels in retinal pigment epithelium (RPE) cells of healthy and early AMD affected human donor eyes. Rs3793784 conferred a small increase in risk for late AMD in the Dutch population (The Rotterdam and AMRO-NL study), but this was not replicated in two non-European studies (AREDS, Columbia University). In addition, the AMRO-NL study revealed no significant association for 9 other variants spanning ERCC6. Finally, we determined that ERCC6 expression in the human RPE did not depend on rs3793784 genotype, but, interestingly, on AMD status: Early AMD-affected donor eyes had a 50% lower ERCC6 expression than healthy donor eyes (P?=?0.018). Conclusions/Significance Our meta-analysis of four Caucasian cohorts does not replicate the reported association between SNPs in ERCC6 and AMD. Nevertheless, our findings on ERCC6 expression in the RPE suggest that ERCC6 may be functionally involved in AMD. Combining our data with those of the literature, we hypothesize that the AMD-related reduced transcriptional activity of ERCC6 may be caused by diverse, small and heterogeneous genetic and/or environmental determinants. PMID:21072178

  4. 6-hydroxydopamine-induced degeneration of nigral dopamine neurons: differential effect on nigral and striatal D-1 dopamine receptors

    SciTech Connect

    Porceddu, M.L.; Giorgi, O.; De Montis, G.; Mele, S.; Cocco, L.; Ongini, E.; Biggio, G.

    1987-08-10

    Dopamine-sensitive adenylate cyclase and TH-SCH 23390 binding parameters were measured in the rat substantia nigra and striatum 15 days after the injection of 6-hydroxydopamine into the medial forebrain bundle. The activity of nigral dopamine-sensitive adenylate cyclase and the binding of TH-SCH 23390 to rat nigral D-1 dopamine receptors were markedly decreased after the lesion. On the contrary, 6-hydroxydopamine-induced degeneration of the nigrostriatal dopamine pathway enhanced both adenylate cyclase activity and the density of TH-SCH 23390 binding sites in striatal membrane preparations. The changes in TH-SCH 23390 binding found in both nigral and striatal membrane preparations were associated with changes in the total number of binding sites with no modifications in their apparent affinity. The results indicate that: a) within the substantia nigra a fraction (30%) of D-1 dopamine receptors coupled to the adenylate cyclase is located on cell bodies and and/or dendrites of dopaminergic neurons; b) striatal D-1 dopamine receptors are tonically innervated by nigrostriatal afferent fibers. 24 references, 1 figure, 1 table.

  5. Increased expression of matrix metalloproteinase-10, nerve growth factor and substance P in the painful degenerate intervertebral disc

    PubMed Central

    Richardson, Stephen M; Doyle, Paul; Minogue, Ben M; Gnanalingham, Kanna; Hoyland, Judith A

    2009-01-01

    Introduction Matrix metalloproteinases (MMPs) are known to be involved in the degradation of the nucleus pulposus (NP) during intervertebral disc (IVD) degeneration. This study investigated MMP-10 (stromelysin-2) expression in the NP during IVD degeneration and correlated its expression with pro-inflammatory cytokines and molecules involved in innervation and nociception during degeneration which results in low back pain (LBP). Methods Human NP tissue was obtained at postmortem (PM) from patients without a history of back pain and graded as histologically normal or degenerate. Symptomatic degenerate NP samples were also obtained at surgery for LBP. Expression of MMP-10 mRNA and protein was analysed using real-time polymerase chain reaction and immunohistochemistry. Gene expression for pro-inflammatory cytokines interleukin-1 (IL-1) and tumour necrosis factor-alpha (TNF-?), nerve growth factor (NGF) and the pain-associated neuropeptide substance P were also analysed. Correlations between MMP-10 and IL-1, TNF-? and NGF were assessed along with NGF with substance P. Results MMP-10 mRNA was significantly increased in surgical degenerate NP when compared to PM normal and PM degenerate samples. MMP-10 protein was also significantly higher in degenerate surgical NP samples compared to PM normal. IL-1 and MMP-10 mRNA demonstrated a significant correlation in surgical degenerate samples, while TNF-? was not correlated with MMP-10 mRNA. NGF was significantly correlated with both MMP-10 and substance P mRNA in surgical degenerate NP samples. Conclusions MMP-10 expression is increased in the symptomatic degenerate IVD, where it may contribute to matrix degradation and initiation of nociception. Importantly, this study suggests differences in the pathways involved in matrix degradation between painful and pain-free IVD degeneration. PMID:19695094

  6. Matrix metalloproteinase expression levels suggest distinct enzyme roles during lumbar disc herniation and degeneration

    PubMed Central

    Bachmeier, Beatrice E.; Nerlich, Andreas; Mittermaier, Norbert; Weiler, Christoph; Lumenta, Christianto; Wuertz, Karin

    2009-01-01

    The disruption of the extracellular disc matrix is a major hallmark of disc degeneration. This has previously been shown to be associated with an up-regulation of major matrix metalloproteinase (MMP) expression and activity. However, until now hardly any data are available for MMP/TIMP regulation and thereby no concept exists as to which MMP/TIMP plays a major role in disc degeneration. The objective of this study was, therefore, to identify and quantify the putative up-regulation of MMPs/TIMPs on the mRNA and protein level and their activity in disc material in relation to clinical data and histological evidence for disc degeneration. A quantitative molecular analysis of the mRNA expression levels for the MMPs (MMPs-1, -2, -3, -7, -8, -9, -13) and the MMP inhibitors (TIMPs-1 and -2) was performed on 37 disc specimens obtained from symptomatic disc herniation or degeneration. In addition, disc specimens from patients without disc degeneration/herniation (=controls) were analyzed. Expression of MMPs-1, -2, -3, -7, -8, -9, -13 and TIMPs-1, -2 was analyzed using quantitative RT-PCR, normalized to the expression level of a house keeping gene (GAPDH). Gene expression patterns were correlated with MMP activity (in situ zymography), protein expression patterns (immunohistochemistry), degeneration score (routine histology) and clinical data. MMP-3 mRNA levels were consistently and substantially up-regulated in samples with histological evidence for disc degeneration. A similar but less pronounced up-regulation was observed for MMP-8. This up-regulation was paralleled by the expression of TIMP-1 and to a lesser extent TIMP-2. In general, these findings could be confirmed with regard to protein expression and enzyme activity. This study provides data on the gene and protein level, which highlights the key role of MMP-3 in the degenerative cascade leading to symptomatic disc degeneration and herniation. Control of the proteolytic activity of MMP-3 may, therefore, come into the focus when aiming to develop new treatment options for early disc degeneration. PMID:19466462

  7. Prevalence of Disc Degeneration in Asymptomatic Korean Subjects. Part 1 : Lumbar Spine

    PubMed Central

    Lee, Tae Hoon; Lim, Soo Mee

    2013-01-01

    Objective Asymptomatic patients show high degeneration prevalence at lumbar disc in previous literatures. Unfortunately, there are few Korean data, so the authors attempted to analyze the prevalence of disc degeneration in highly selective asymptomatic Korean subjects using MRI. Methods We performed 3 T MRI sagittal scans from T12 to S1 on 102 asymptomatic subjects (50 men and 52 women) who visited our hospital between the ages of 14 and 82 years (mean age 46.3 years). All images were read independently by three observers (two neurosurgeons and one neuroradiologist) who were not given any information about the subjects. We classified grading for lumbar disc herniation (HN), annular fissure (AF), and nucleus degeneration (ND), using disc degeneration classification. Results The prevalence of HN, AF, and ND were 81.4%, 76.1%, and 75.8% respectively. Almost all levels showed an age-related proportional tendency with some exceptions. Conclusion In asymptomatic Korean subjects, the abnormal findings showed high prevalence of AF, ND, and extrusion. Especially in young ages, the authors found that bulging, protrusion, and AF showed high prevalence at L4/5 and L5/S1. And ND showed high prevalence at L5/S1. So, all lumbar disc degenerations are not pathologic, especially in children and adolescents. PMID:23440899

  8. Effect of disc degeneration on the muscle recruitment pattern in upright posture: a computational analysis.

    PubMed

    Kim, Young Eun; Choi, Hae Won

    2015-01-01

    Based on the sensor driving control mechanism model, the effect of disc degeneration on the trunk muscle recruitment (TMR) pattern was analysed in erect standing posture. A previously developed computational model was used for this analysis, with modifications incorporating the T12-L1 motion segment and additional muscle fascicles. To generate disc degeneration at three different levels (L3-L4, L4-L5, or L5-S1), the material properties of the ground matrix of the annulus and bulk modulus of the nucleus were reduced. The finite element method combined with an optimization technique was applied to calculate the muscle forces. Minimization of deviations in the averaged tensile stress in the annulus fibres at the outermost layer in the five discs was selected for muscle force calculations. The results indicated that the disc degeneration noticeably increased the activation of the superficial muscle (IT and R) even though there was no clear change in the longissimus thoracis. Unlike some of the superficial muscles, activation in the deep muscles (multifidus (ML, MS, MT), LL and Q) was decreased. The change in TMR pattern generated an intervertebral disc angle difference and nucleus pressure increased in the upper level. These differences are expected to be functional in that they reduce the stress at the degenerated disc by changing the muscle activation, which slows down the progress of disc degeneration. PMID:25025614

  9. Evidence for degeneration of the Y chromosome in the dioecious plant Silene latifolia.

    PubMed

    Marais, Gabriel A B; Nicolas, Michael; Bergero, Roberta; Chambrier, Pierre; Kejnovsky, Eduard; Monéger, Françoise; Hobza, Roman; Widmer, Alex; Charlesworth, Deborah

    2008-04-01

    The human Y--probably because of its nonrecombining nature--has lost 97% of its genes since X and Y chromosomes started to diverge [1, 2]. There are clear signs of degeneration in the Drosophila miranda neoY chromosome (an autosome fused to the Y chromosome), with neoY genes showing faster protein evolution [3-6], accumulation of unpreferred codons [6], more insertions of transposable elements [5, 7], and lower levels of expression [8] than neoX genes. In the many other taxa with sex chromosomes, Y degeneration has hardly been studied. In plants, many genes are expressed in pollen [9], and strong pollen selection may oppose the degeneration of plant Y chromosomes [10]. Silene latifolia is a dioecious plant with young heteromorphic sex chromosomes [11, 12]. Here we test whether the S. latifolia Y chromosome is undergoing genetic degeneration by analyzing seven sex-linked genes. S. latifolia Y-linked genes tend to evolve faster at the protein level than their X-linked homologs, and they have lower expression levels. Several Y gene introns have increased in length, with evidence for transposable-element accumulation. We detect signs of degeneration in most of the Y-linked gene sequences analyzed, similar to those of animal Y-linked and neo-Y chromosome genes. PMID:18394889

  10. Genetic degeneration of old and young Y chromosomes in the flowering plant Rumex hastatulus

    PubMed Central

    Hough, Josh; Hollister, Jesse D.; Wang, Wei; Barrett, Spencer C. H.; Wright, Stephen I.

    2014-01-01

    Heteromorphic sex chromosomes have originated independently in many species, and a common feature of their evolution is the degeneration of the Y chromosome, characterized by a loss of gene content and function. Despite being of broad significance to our understanding of sex chromosome evolution, the genetic changes that occur during the early stages of Y-chromosome degeneration are poorly understood, especially in plants. Here, we investigate sex chromosome evolution in the dioecious plant Rumex hastatulus, in which X and Y chromosomes have evolved relatively recently and occur in two distinct systems: an ancestral XX/XY system and a derived XX/XY1Y2 system. This polymorphism provides a unique opportunity to investigate the effect of sex chromosome age on patterns of divergence and gene degeneration within a species. Despite recent suppression of recombination and low X-Y divergence in both systems, we find evidence that Y-linked genes have started to undergo gene loss, causing ?28% and ?8% hemizygosity of the ancestral and derived X chromosomes, respectively. Furthermore, genes remaining on Y chromosomes have accumulated more amino acid replacements, contain more unpreferred changes in codon use, and exhibit significantly reduced gene expression compared with their X-linked alleles, with the magnitude of these effects being greatest for older sex-linked genes. Our results provide evidence for reduced selection efficiency and ongoing Y-chromosome degeneration in a flowering plant, and indicate that Y degeneration can occur soon after recombination suppression between sex chromosomes. PMID:24825885

  11. Impaired Mitochondrial Energy Production Causes Light-Induced Photoreceptor Degeneration Independent of Oxidative Stress

    PubMed Central

    Jaiswal, Manish; Haelterman, Nele A.; Sandoval, Hector; Xiong, Bo; Donti, Taraka; Kalsotra, Auinash; Yamamoto, Shinya; Cooper, Thomas A.; Graham, Brett H.; Bellen, Hugo J.

    2015-01-01

    Two insults often underlie a variety of eye diseases including glaucoma, optic atrophy, and retinal degeneration—defects in mitochondrial function and aberrant Rhodopsin trafficking. Although mitochondrial defects are often associated with oxidative stress, they have not been linked to Rhodopsin trafficking. In an unbiased forward genetic screen designed to isolate mutations that cause photoreceptor degeneration, we identified mutations in a nuclear-encoded mitochondrial gene, ppr, a homolog of human LRPPRC. We found that ppr is required for protection against light-induced degeneration. Its function is essential to maintain membrane depolarization of the photoreceptors upon repetitive light exposure, and an impaired phototransduction cascade in ppr mutants results in excessive Rhodopsin1 endocytosis. Moreover, loss of ppr results in a reduction in mitochondrial RNAs, reduced electron transport chain activity, and reduced ATP levels. Oxidative stress, however, is not induced. We propose that the reduced ATP level in ppr mutants underlies the phototransduction defect, leading to increased Rhodopsin1 endocytosis during light exposure, causing photoreceptor degeneration independent of oxidative stress. This hypothesis is bolstered by characterization of two other genes isolated in the screen, pyruvate dehydrogenase and citrate synthase. Their loss also causes a light-induced degeneration, excessive Rhodopsin1 endocytosis and reduced ATP without concurrent oxidative stress, unlike many other mutations in mitochondrial genes that are associated with elevated oxidative stress and light-independent photoreceptor demise. PMID:26176594

  12. Genetic degeneration of old and young Y chromosomes in the flowering plant Rumex hastatulus.

    PubMed

    Hough, Josh; Hollister, Jesse D; Wang, Wei; Barrett, Spencer C H; Wright, Stephen I

    2014-05-27

    Heteromorphic sex chromosomes have originated independently in many species, and a common feature of their evolution is the degeneration of the Y chromosome, characterized by a loss of gene content and function. Despite being of broad significance to our understanding of sex chromosome evolution, the genetic changes that occur during the early stages of Y-chromosome degeneration are poorly understood, especially in plants. Here, we investigate sex chromosome evolution in the dioecious plant Rumex hastatulus, in which X and Y chromosomes have evolved relatively recently and occur in two distinct systems: an ancestral XX/XY system and a derived XX/XY1Y2 system. This polymorphism provides a unique opportunity to investigate the effect of sex chromosome age on patterns of divergence and gene degeneration within a species. Despite recent suppression of recombination and low X-Y divergence in both systems, we find evidence that Y-linked genes have started to undergo gene loss, causing ? 28% and ? 8% hemizygosity of the ancestral and derived X chromosomes, respectively. Furthermore, genes remaining on Y chromosomes have accumulated more amino acid replacements, contain more unpreferred changes in codon use, and exhibit significantly reduced gene expression compared with their X-linked alleles, with the magnitude of these effects being greatest for older sex-linked genes. Our results provide evidence for reduced selection efficiency and ongoing Y-chromosome degeneration in a flowering plant, and indicate that Y degeneration can occur soon after recombination suppression between sex chromosomes. PMID:24825885

  13. Reduced vesicular storage of catecholamines causes progressive degeneration in the locus ceruleus

    PubMed Central

    Taylor, Tonya N.; Alter, Shawn P.; Wang, Minzheng; Goldstein, David S.; Miller, Gary W.

    2014-01-01

    Parkinson’s disease (PD) is the most common neurodegenerative motor disease. Pathologically, PD is characterized by Lewy body deposition and subsequent death of dopamine neurons in the substantia nigra pars compacta. PD also consistently features degeneration of the locus ceruleus, the main source of norepinephrine in the central nervous system. We have previously reported a mouse model of dopaminergic neurodegeneration based on reduced expression of the vesicular monoamine transporter (VMAT2 LO). To determine if reduced vesicular storage can also cause noradrenergic degeneration, we examined indices of damage to the catecholaminergic systems in brain and cardiac tissue of VMAT2 LO mice. At two months of age, neurochemical analyses revealed substantial reductions in striatal dopamine (94%), cortical dopamine (57%) and norepinephrine (54%), as well as cardiac norepinephrine (97%). These losses were accompanied by increased conversion of dopamine and norepinephrine to their deaminated metabolites. VMAT2 LO mice exhibited loss of noradrenergic innervation in the cortex, as determined by norepinephrine transporter immunoreactivity and 3H-nisoxetine binding. Using unbiased stereological techniques, we observed progressive degeneration in the locus ceruleus that preceded degeneration of the substantia nigra pars compacta. In contrast, the ventral tegmental area, which is spared in human PD, remained unaffected. The coordinate loss of dopamine and norepinephrine neurons in VMAT2-LO mice parallels the pattern of neurodegeneration that occurs in human PD, and demonstrates that insufficient catecholamine storage can cause spontaneous degeneration in susceptible neurons, underscoring cytosolic catecholamine catabolism as a determinant of neuronal susceptibility in PD. PMID:24025942

  14. Compressive and rarefactive dust ion-acoustic solitary waves with degenerate electron-positron-ion plasma

    NASA Astrophysics Data System (ADS)

    Mukta, K. N.; Zobaer, M. S.; Roy, N.; Mamun, A. A.

    2015-06-01

    The nonlinear propagation of dust ion-acoustic (DIA) waves in a unmagnetized collisionless degenerate dense plasma (containing degenerate electron and positron, and classical ion fluids) has been theoretically investigated. The K-dV equation has been derived by employing the reductive perturbation method and by taking into account the effect of different plasma parameters in plasma fluid. The stationary solitary wave solution of K-dV equation is obtained, and numerically analyzed to identify the basic properties of DIA solitary structures. It has been shown that depending on plasma parametric values, the degenerate plasma under consideration supports compressive or rarefactive solitary structures. It has been also found that the effect of pressures on electrons, ions, and positrons significantly modify the basic features of solitary waves that are found to exist in such a plasma system. The relevance of our results in astrophysical objects such as white dwarfs and neutron stars, which are of scientific interest, is discussed briefly.

  15. Matrix elements of doubly degenerate vibrations and the Herzberg-Teller series

    NASA Astrophysics Data System (ADS)

    Smith, W. L.

    2011-10-01

    The non-zero terms in doubly degenerate vibrations in the Herzberg-Teller series are discussed and simplified formulae for the matrix elements for transitions between the degenerate l-components of such vibrational levels in upper and lower electronic states are given, with the emphasis on the change of vibrational frequency accompanying the transition. The results are applied to the analysis of degenerate components in the ?6 and ?16 vibrational transitions in the benzene AB2u-XA1g system, and it is shown that in cases where the second order Herzberg-Teller terms are important, cancelation effects in the matrix elements can lead to the disappearance of certain transitions which are otherwise allowed.

  16. Cosmological constant in SUGRA models with Planck scale SUSY breaking and degenerate vacua

    E-print Network

    C. D. Froggatt; R. Nevzorov; H. B. Nielsen; A. W. Thomas

    2014-10-08

    The empirical mass of the Higgs boson suggests small to vanishing values of the quartic Higgs self--coupling and the corresponding beta function at the Planck scale, leading to degenerate vacua. This leads us to suggest that the measured value of the cosmological constant can originate from supergravity (SUGRA) models with degenerate vacua. This scenario is realised if there are at least three exactly degenerate vacua. In the first vacuum, associated with the physical one, local supersymmetry (SUSY) is broken near the Planck scale while the breakdown of the SU(2)_W\\times U(1)_Y symmetry takes place at the electroweak (EW) scale. In the second vacuum local SUSY breaking is induced by gaugino condensation at a scale which is just slightly lower than \\Lambda_{QCD} in the physical vacuum. Finally, in the third vacuum local SUSY and EW symmetry are broken near the Planck scale.

  17. Differential scanning calorimetric studies of superficial digital flexor tendon degeneration in the horse.

    PubMed

    Miles, C A; Wardale, R J; Birch, H L; Bailey, A J

    1994-07-01

    Differential scanning calorimetry (DSC) of equine superficial digital flexor tendons revealed the presence of a small exothermic peak at 23 degrees C of unknown origin, and a large endothermic peak at 70 degrees C due to denaturation of cross-linked collagen fibres. In the central degenerated core of damaged tendons the denaturation temperature remained at 70 degrees C but the enthalpy decreased in relation to the extent of degeneration of the tendon. We suggest that this reduction in enthalpy is due to depolymerisation and denaturation of the collagen fibres. This contention is supported by the observed increased activity of the degradative enzyme cathepsin B secreted by the fibroblasts. DSC analysis of cultured porcine tendon fibroblasts revealed a multicomponent endotherm, denaturation beginning at 46 degrees C, a temperature capable of being achieved within the tendon during intensive exercise. DSC clearly has considerable potential in complementing morphological and biochemical studies to determine the aetiology and progress of equine tendon degeneration. PMID:8575396

  18. Independent degeneration of photoreceptors and retinal pigment epithelium in conditional knockout mouse models of choroideremia

    PubMed Central

    Tolmachova, Tanya; Anders, Ross; Abrink, Magnus; Bugeon, Laurence; Dallman, Margaret J.; Futter, Clare E.; Ramalho, José S.; Tonagel, Felix; Tanimoto, Naoyuki; Seeliger, Mathias W.; Huxley, Clare; Seabra, Miguel C.

    2006-01-01

    Choroideremia (CHM) is an X-linked degeneration of the retinal pigment epithelium (RPE), photoreceptors, and choroid, caused by loss of function of the CHM/REP1 gene. REP1 is involved in lipid modification (prenylation) of Rab GTPases, key regulators of intracellular vesicular transport and organelle dynamics. To study the pathogenesis of CHM and to develop a model for assessing gene therapy, we have created a conditional mouse knockout of the Chm gene. Heterozygous-null females exhibit characteristic hallmarks of CHM: progressive degeneration of the photoreceptors, patchy depigmentation of the RPE, and Rab prenylation defects. Using tamoxifen-inducible and tissue-specific Cre expression in combination with floxed Chm alleles, we show that CHM pathogenesis involves independently triggered degeneration of photoreceptors and the RPE, associated with different subsets of defective Rabs. PMID:16410831

  19. Clinical features of spongy degeneration of the central nervous system in two Labrador retriever littermates.

    PubMed

    O'Brien, D P; Zachary, J F

    1985-06-01

    Spongy degeneration of the CNS was diagnosed in 2 female Labrador Retriever littermates. The dogs had histories of progressive cerebellar ataxia and episodes of extreme extensor rigidity beginning at 4 and 6 months of age. One had a history of hearing difficulties. When examined at 9 months of age, both dogs had moderate ataxia and dysmetria of the head, trunk, and limbs, hyperreflexia with clonus, and extensor rigidity with episodes of exaggerated rigidity and opisthotonos. One dog was euthanatized and the other was monitored for 2 months, during which time her signs progressed to severe dysmetria, weakness, muscle atrophy, and rigidity with marked hyperreflexia. Necropsy of both dogs revealed astrocytic abnormalities and spongy degeneration of the white matter of the CNS. The clinical signs and postmortem findings were similar to the juvenile form of spongy degeneration in man. PMID:4008303

  20. Safranal, a saffron constituent, attenuates retinal degeneration in P23H rats.

    PubMed

    Fernández-Sánchez, Laura; Lax, Pedro; Esquiva, Gema; Martín-Nieto, José; Pinilla, Isabel; Cuenca, Nicolás

    2012-01-01

    Saffron, an extract from Crocus sativus, has been largely used in traditional medicine for its antiapoptotic and anticarcinogenic properties. In this work, we investigate the effects of safranal, a component of saffron stigmas, in attenuating retinal degeneration in the P23H rat model of autosomal dominant retinitis pigmentosa. We demonstrate that administration of safranal to homozygous P23H line-3 rats preserves both photoreceptor morphology and number. Electroretinographic recordings showed higher a- and b-wave amplitudes under both photopic and scotopic conditions in safranal-treated versus non-treated animals. Furthermore, the capillary network in safranal-treated animals was preserved, unlike that found in untreated animals. Our findings indicate that dietary supplementation with safranal slows photoreceptor cell degeneration and ameliorates the loss of retinal function and vascular network disruption in P23H rats. This work also suggests that safranal could be potentially useful to retard retinal degeneration in patients with retinitis pigmentosa. PMID:22900092

  1. Water induced relaxation of a degenerate vibration of guanidinium using 2D IR echo spectroscopy

    PubMed Central

    Vorobyev, Dmitriy Yu.; Kuo, Chun-Hung; Kuroda, Daniel G.; Scott, J. Nathan; Vanderkooi, Jane M.; Hochstrasser, Robin M.

    2010-01-01

    The nearly degenerate asymmetric stretch vibrations near 1600 cm?1 of the guanidinium cation in D-glycerol/D2O mixtures having different viscosity were studied by 2D IR photon echo spectroscopy. The polarization dependent photon echo signal shows two separate frequency distributions in the 2D spectrum in D2O, even though only one band is evident from inspection of the linear FTIR spectrum. The split components are more clearly seen at higher viscosity. The interactions with solvent induce energy transfer between the degenerate component modes on the time scale of 0.5 ps. The energy transfer between modes is directly observed in 2D IR and distinguished by the waiting time dependence of the cross peaks from the transfers between threefold symmetric configurations of the distorted ion and solvent. The 2D IR analysis carried out for various polarization conditions required specification of frequency-frequency auto- and cross- correlation functions for the degenerate components. PMID:20143800

  2. Biomechanical and rheological characterization of mild intervertebral disc degeneration in a large animal model.

    PubMed

    Detiger, Suzanne E L; Hoogendoorn, Roel J W; van der Veen, Albert J; van Royen, Barend J; Helder, Marco N; Koenderink, Gijsje H; Smit, Theo H

    2013-05-01

    Biomechanical properties of healthy and degenerated nucleus pulposus (NP) are thought to be important for future regenerative strategies for intervertebral disc (IVD) repair. However, which properties are pivotal as design criteria when developing NP replacement materials is ill understood. Therefore, we determined and compared segmental biomechanics and NP viscoelastic properties in normal and mildly degenerated discs. In eight goats, three lumbar IVDs were chemically degenerated using chondroitinase ABC (CABC), confirmed with radiography and MRI after euthanasia 12 weeks post-operative. Neutral zone (NZ) stiffness and range of motion (ROM) were determined sagitally, laterally, and rotationally for each spinal motion segment (SMS) using a mechanical testing device. NPs were isolated for oscillatory shear experiments; elastic and viscous shear moduli followed from the ratio between shear stress and strain. Water content was quantified by weighing before and after freeze-drying. Disc height on radiographs and signal intensity on MRI decreased (6% and 22%, respectively, p?degeneration provides a good model of disc degeneration. Furthermore, CABC-injected IVDs had significantly lower NZ stiffness and larger ROM in lateral bending (LB) and axial rotation (AR) than controls. Rheometry consistently revealed significantly lower (10-12%) viscoelastic moduli after mild degeneration within goats, though the inter-animal differences were relatively large (complex modulus ?12 to 41?kPa). Relative water content in the NP was unaffected by CABC, remaining at ?75%. These observations suggest that viscoelastic properties have a marginal influence on mechanical behavior of the whole SMS. Therefore, when developing replacement materials the focus should be on other design criteria, such as biochemical cues and swelling pressure. PMID:23255234

  3. The Progenitors of Type Ia Supernovae. II. Are they Double-degenerate Binaries? The Symbiotic Channel

    NASA Astrophysics Data System (ADS)

    Di Stefano, R.

    2010-08-01

    In order for a white dwarf (WD) to achieve the Chandrasekhar mass, MC , and explode as a Type Ia supernova (SNIa), it must interact with another star, either accreting matter from or merging with it. The failure to identify the class or classes of binaries which produce SNeIa is the long-standing "progenitor problem." Its solution is required if we are to utilize the full potential of SNeIa to elucidate basic cosmological and physical principles. In single-degenerate models, a WD accretes and burns matter at high rates. Nuclear-burning white dwarfs (NBWDs) with mass close to MC are hot and luminous, potentially detectable as supersoft X-ray sources (SSSs). In previous work, we showed that >90%-99% of the required number of progenitors do not appear as SSSs during most of the crucial phase of mass increase. The obvious implication might be that double-degenerate binaries form the main class of progenitors. We show in this paper, however, that many binaries that later become double degenerates must pass through a long-lived NBWD phase during which they are potentially detectable as SSSs. The paucity of SSSs is therefore not a strong argument in favor of double-degenerate models. Those NBWDs that are the progenitors of double-degenerate binaries are likely to appear as symbiotic binaries for intervals >106 years. In fact, symbiotic pre-double-degenerates should be common, whether or not the WDs eventually produce SNeIa. The key to solving the Type Ia progenitor problem lies in understanding the appearance of NBWDs. Most of them do not appear as SSSs most of the time. We therefore consider the evolution of NBWDs to address the question of what their appearance may be and how we can hope to detect them.

  4. THE PROGENITORS OF TYPE Ia SUPERNOVAE. II. ARE THEY DOUBLE-DEGENERATE BINARIES? THE SYMBIOTIC CHANNEL

    SciTech Connect

    Di Stefano, R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St. Cambridge, MA 02138 (United States)

    2010-08-10

    In order for a white dwarf (WD) to achieve the Chandrasekhar mass, M{sub C} , and explode as a Type Ia supernova (SNIa), it must interact with another star, either accreting matter from or merging with it. The failure to identify the class or classes of binaries which produce SNeIa is the long-standing 'progenitor problem'. Its solution is required if we are to utilize the full potential of SNeIa to elucidate basic cosmological and physical principles. In single-degenerate models, a WD accretes and burns matter at high rates. Nuclear-burning white dwarfs (NBWDs) with mass close to M{sub C} are hot and luminous, potentially detectable as supersoft X-ray sources (SSSs). In previous work, we showed that >90%-99% of the required number of progenitors do not appear as SSSs during most of the crucial phase of mass increase. The obvious implication might be that double-degenerate binaries form the main class of progenitors. We show in this paper, however, that many binaries that later become double degenerates must pass through a long-lived NBWD phase during which they are potentially detectable as SSSs. The paucity of SSSs is therefore not a strong argument in favor of double-degenerate models. Those NBWDs that are the progenitors of double-degenerate binaries are likely to appear as symbiotic binaries for intervals >10{sup 6} years. In fact, symbiotic pre-double-degenerates should be common, whether or not the WDs eventually produce SNeIa. The key to solving the Type Ia progenitor problem lies in understanding the appearance of NBWDs. Most of them do not appear as SSSs most of the time. We therefore consider the evolution of NBWDs to address the question of what their appearance may be and how we can hope to detect them.

  5. Glucosamine and chondroitin sulfate supplementation to treat symptomatic disc degeneration: Biochemical rationale and case report

    PubMed Central

    van Blitterswijk, Wim J; van de Nes, Jos CM; Wuisman, Paul IJM

    2003-01-01

    Background Glucosamine and chondroitin sulfate preparations are widely used as food supplements against osteoarthritis, but critics are skeptical about their efficacy, because of the lack of convincing clinical trials and a reasonable scientific rationale for the use of these nutraceuticals. Most trials were on osteoarthritis of the knee, while virtually no documentation exists on spinal disc degeneration. The purpose of this article is to highlight the potential of these food additives against cartilage degeneration in general, and against symptomatic spinal disc degeneration in particular, as is illustrated by a case report. The water content of the intervertebral disc is a reliable measure of its degeneration/ regeneration status, and can be objectively determined by Magnetic Resonance Imaging (MRI) signals. Case presentation Oral intake of glucosamine and chondroitin sulfate for two years associated with disk recovery (brightening of MRI signal) in a case of symptomatic spinal disc degeneration. We provide a biochemical explanation for the possible efficacy of these nutraceuticals. They are bioavailable to cartilage chondrocytes, may stimulate the biosynthesis and inhibit the breakdown of their extracellular matrix proteoglycans. Conclusion The case suggests that long-term glucosamine and chondroitin sulfate intake may counteract symptomatic spinal disc degeneration, particularly at an early stage. However, definite proof requires well-conducted clinical trials with these food supplements, in which disc de-/regeneration can be objectively determined by MRI. A number of biochemical reasons (that mechanistically need to be further resolved) explain why these agents may have cartilage structure- and symptom-modifying effects, suggesting their therapeutic efficacy against osteoarthritis in general. PMID:12797867

  6. Aquaporin-4 mitigates retrograde degeneration of rubrospinal neurons by facilitating edema clearance and glial scar formation after spinal cord injury in mice.

    PubMed

    Wu, Qi; Zhang, Yong-Jie; Gao, Jun-Ying; Li, Xiu-Miao; Kong, Hui; Zhang, Yi-Ping; Xiao, Ming; Shields, Christopher B; Hu, Gang

    2014-06-01

    Atrophy of upper motor neurons hampers axonal regeneration and functional recovery following spinal cord injury (SCI). Apart from the severity of primary injury, a series of secondary pathological damages including spinal cord edema and glial scar formation affect the fate of injured upper motor neurons. The aquaporin-4 (AQP4) water channel plays a critical role in water homeostasis and migration of astrocytes in the central nervous system, probably offering a new therapeutic target for protecting against upper motor neuron degeneration after SCI. To test this hypothesis, we examined the effect of AQP4 deficiency on atrophy of rubrospinal neurons after unilateral rubrospinal tract transection at the fourth cervical level in mice. AQP4 gene knockout (AQP4-/-) mice exhibited high extent of spinal cord edema at 72 h after lesion compared with wild-type littermates. AQP4-/- mice showed impairments in astrocyte migration toward the transected site with a greater lesion volume at 1 week after surgery and glial scar formation with a larger cyst volume at 6 weeks. More severe atrophy and loss of axotomized rubrospinal neurons as well as axonal degeneration in the rubrospinal tract rostral to the lesion were observed in AQP4-/- mice at 6 weeks after SCI. AQP4 expression was downregulated at the lesioned spinal segment at 3 days and 1 week after injury, but upregulated at 6 weeks. These results demonstrated that AQP4 not only mitigates spinal cord damage but also ameliorates retrograde degeneration of rubrospinal neurons by promoting edema clearance and glial scar formation after laceration SCI. This finding supports the notion that AQP4 may be a promising therapeutic target for SCI. PMID:24390474

  7. Degenerate first-order Hamiltonian operators of hydrodynamic type in 2D

    NASA Astrophysics Data System (ADS)

    Savoldi, Andrea

    2015-07-01

    First-order Hamiltonian operators of hydrodynamic type were introduced by Drubrovin and Novikov in 1983. In 2D, they are generated by a pair of contravariant metrics g, \\tilde{g} and a pair of differential-geometric objects b, \\tilde{b}. If the determinant of the pencil g+? \\tilde{g} vanishes for all ?, the operator is called degenerate. In this paper we provide a complete classification of degenerate two- and three-component Hamiltonian operators. Moreover, we study the integrability, by the method of hydrodynamic reductions, of 2+1 Hamiltonian systems arising from the structures we classified.

  8. Genetic Association of Apolipoprotein E with Age-Related Macular Degeneration

    Microsoft Academic Search

    Caroline C. W. Klaver; Mike Kliffen; Cornelia M. van Duijn; Albert Hofman; Marc Cruts; Diederick E. Grobbee; Christine van Broeckhoven

    1998-01-01

    Age-related macular degeneration (AMD) is the most common geriatric eye\\u000a disorder leading to blindness and is characterized by degeneration of the\\u000a neuroepithelium in the macular area of the eye. Apolipoprotein E (apoE),\\u000a the major apolipoprotein of the CNS and an important regulator of\\u000a cholesterol and lipid transport, appears to be associated with\\u000a neurodegeneration. The apoE gene (APOE) polymorphism is a

  9. Degeneration of salivary glands of males of the tick Rhipicephalus sanguineus (Latreille, 1806) (Acari, Ixodidae).

    PubMed

    Furquim, Karim Christina Scopinho; Bechara, Gervásio Henrique; Camargo Mathias, Maria Izabel

    2008-07-01

    The present study examined the salivary glands of Rhipicephalus sanguineus males at days 0, 3, and 7 post-detachment from the host. Degeneration of this organ occurred in the three stages and it advanced as time away from the host progressed. Thus, characteristics of degeneration were more prominent in males at day 7 post-detachment than in males at day 0 post-detachment. In males at day 0 post-detachment, type I acini were intact; while in other stages these acini exhibited signs of degeneration. In type II acini of individuals at day 0 post-detachment, cells a, c1-c5, c8, and indeterminate were identified. Only c1 and c8 were intact. The remaining cell types were undergoing degeneration, as well as all cells d-f in type III acini, and all g in type IV acini. In males at day 3 post-detachment from the host, all cells (a, c1-c5, c8 and indeterminate) of type II acini, cells d and e in type III acini, and g in type IV were undergoing degeneration. In some Indeterminate acini, the boundaries of cells still could be distinguished, while in others, only a cytoplasmic mass was observed. At day 3 post-detachment, apoptotic bodies were present. In males at day 7 post-detachment from the host, the degeneration process progressed. All cells a, c1, c3-c5, c8 and indeterminate in type II, and d and e in type III acini were undergoing degeneration. Type IV acini still contained remnants of secretion and in Indeterminate acini, only a cytoplasmic mass could be observed. At this stage, apoptotic bodies were also present. The present study still revealed that cells of salivary glands of R. sanguineus males when degenerating undergo the following changes: (a) decrease in secretion production with or without granule breakage, (b) changes in nuclear morphology, (c) cytoplasm shrinkage, (d) loss of cell shape, (e) loss of cell boundaries, and (e) cytoplasmic vacuolation. Together, these changes result in cell fragmentation with release of apoptotic bodies. PMID:18450383

  10. On periodic responses generated by a degenerate analog neuron model with periodic inputs.

    PubMed

    Yoshida, T

    1987-01-01

    Periodic responses to periodically varying stimulating pulse sequences are mathematically described for a degenerate analog neuron model. The model used was derived by Yoshizawa et al. (1982) in their investigation of the state transition of an electronic model using a tunnel diode in a degenerate case. Periodic responses to constant pulse sequences for the model were described by them. In this paper, it is shown that periodic responses to periodically varying pulse sequences for the model are identical with those which the author previously described for a discrete neuron model. PMID:3036254

  11. Temperature corrections to the thermodynamic functions of a degenerate neutron gas in a magnetic field

    SciTech Connect

    Skobelev, V. V., E-mail: v.skopbelev@inbox.ru [Moscow State Industrial University (Russian Federation)

    2011-08-15

    Temperature corrections to the basic thermodynamic functions calculated in our earlier publication for a degenerate neutron gas in a magnetic field are determined taking into account the anomalous magnetic moment of a neutron. The heat capacity and entropy of the degenerate neutron gas, as well as the temperature correction to the magnetic susceptibility, are also calculated. Additional arguments supporting the effect of an increase in the pulse frequency of pulsars mentioned in the previous publication are formulated; the results of that publication are refined.

  12. Fin degeneration of young-of-the-year Alosa pseudoharengus (Clupeidae) in southern Lake Michigan

    USGS Publications Warehouse

    Brown, Edward H., Jr.; Norden, Carroll R.

    1970-01-01

    Young-of-the-year alewives, Alosa pseudoharengus, with extremely shortened caudal fins were observed at four locations in southern Lake Michigan between 1964 and 1968. Some of the fins appeared stunted or underdeveloped, but microscopic examination revealed a deterioration of the fins and not an ontogenetic abnormality. Deterioration of the caudal fin was frequently accompanied by degeneration of the dorsal and anal fins. Degenerate fins were not found on other species nor on older alewives, with the exception of one known yearling alewife at Waukegan and possibly a few of the larger fish at Milwaukee.

  13. Classification of nondegenerate equilibria and degenerate 1-dimensional orbits of the Kovalevskaya-Yehia integrable system

    SciTech Connect

    Logacheva, Nina S [M. V. Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow (Russian Federation)

    2012-01-31

    The paper is devoted to a topological analysis of the Kovalevskaya-Yehia integrable case in rigid body dynamics. It is proved that the integral has the Bott property on isoenergy surfaces of the system; the topology of the Liouville foliation in a neighbourhood of degenerate 1-dimensional orbits and equilibria (points of rank 0) is also described. In particular, marked loop molecules are constructed for degenerate 1-dimensional orbits, and a representation in the form of an almost direct product is found for nondegenerate singularities of rank 0. Bibliography: 17 titles.

  14. Assessment of Intervertebral Disc Degeneration Based on Quantitative MRI Analysis: an in vivo study

    PubMed Central

    Grunert, Peter; Hudson, Katherine D.; Macielak, Michael R.; Aronowitz, Eric; Borde, Brandon H.; Alimi, Marjan; Njoku, Innocent; Ballon, Douglas; Tsiouris, Apostolos John; Bonassar, Lawrence J.; Härtl, Roger

    2015-01-01

    Study design Animal experimental study Objective To evaluate a novel quantitative imaging technique for assessing disc degeneration. Summary of Background Data T2-relaxation time (T2-RT) measurements have been used to quantitatively assess disc degeneration. T2 values correlate with the water content of inter vertebral disc tissue and thereby allow for the indirect measurement of nucleus pulposus (NP) hydration. Methods We developed an algorithm to subtract out MRI voxels not representing NP tissue based on T2-RT values. Filtered NP voxels were used to measure nuclear size by their amount and nuclear hydration by their mean T2-RT. This technique was applied to 24 rat-tail intervertebral discs’ (IVDs), which had been punctured with an 18-gauge needle according to different techniques to induce varying degrees of degeneration. NP voxel count and average T2-RT were used as parameters to assess the degeneration process at 1 and 3 months post puncture. NP voxel counts were evaluated against X-ray disc height measurements and qualitative MRI studies based on the Pfirrmann grading system. Tails were collected for histology to correlate NP voxel counts to histological disc degeneration grades and to NP cross-sectional area measurements. Results NP voxel count measurements showed strong correlations to qualitative MRI analyses (R2=0.79, p<0.0001), histological degeneration grades (R2=0.902, p<0.0001) and histological NP cross-sectional area measurements (R2=0.887, p<0.0001). In contrast to NP voxel counts, the mean T2-RT for each punctured group remained constant between months 1 and 3. The mean T2-RTs for the punctured groups did not show a statistically significant difference from those of healthy IVDs (63.55ms ±5.88ms month 1 and 62.61ms ±5.02ms) at either time point. Conclusion The NP voxel count proved to be a valid parameter to quantitatively assess disc degeneration in a needle puncture model. The mean NP T2-RT does not change significantly in needle-puncture induced degenerated IVDs. IVDs can be segmented into different tissue components according to their innate T2-RT. PMID:24384655

  15. Complete quantum control of the population transfer branching ratio between two degenerate target states

    E-print Network

    Jiangbin Gong; Stuart A. Rice

    2004-05-12

    A five-level four-pulse phase-sensitive extended stimulated Raman adiabatic passage scheme is proposed to realize complete control of the population transfer branching ratio between two degenerate target states. The control is achieved via a three-node null eigenstate that can be correlated with an arbitrary superposition of the target states. Our results suggest that complete suppression of the yield of one of two degenerate product states, and therefore absolute selectivity in photochemistry, is achievable and predictable, even without studying the properties of the unwanted product state beforehand.

  16. Smoking and age-related macular degeneration: biochemical mechanisms and patient support.

    PubMed

    Willeford, Kevin T; Rapp, Jerry

    2012-11-01

    A small percentage of the population associates smoking with ocular disease. Most optometrists do not stress the importance of smoking cessation to their patients, and the centrality of smoking regarding the risk for ocular disease is not emphasized in optometric education. Age-related macular degeneration has strong epidemiological associations with smoking, and so serves as an appropriate model for the adverse effects of cigarette smoke on the eye. This article aims to provide basic scientific information to optometrists and optometry students so that they can better understand the pathogenesis of age-related macular degeneration and provide education and support to their patients wishing to stop smoking. PMID:23034338

  17. The degenerate scenario in the NMSSM: Direct singlino-like neutralino searches with a gravitino LSP

    E-print Network

    Grigoris Panotopoulos

    2011-03-01

    A two-component dark matter model is studied adopting the degenerate scenario in the R-parity conserving NMSSM. The gravitino LSP and the neutralino NLSP are extremely degenerate in mass, avoiding the BBN bounds and obtaining a high reheating temperature for thermal leptogenesis to work. In this model both gravitino (absolutely stable) and neutralino (quasi-stable) contribute to dark matter, and direct detection searches for neutralino are discussed. Points that survive all the constraints correspond to a singlino-like neutralino.

  18. Intravitreal bevacizumab (Avastin) for occult choroidal neovascularization in age-related macular degeneration

    Microsoft Academic Search

    S. Aisenbrey; F. Ziemssen; M. Völker; F. Gelisken; P. Szurman; G. Jaissle; S. Grisanti; K. U. Bartz-Schmidt

    2006-01-01

    Background  The purpose of the study is to report data on short-term safety of intravitreal bevacizumab treatment and its effect on visual\\u000a function, central retinal thickness, and angiographical changes of occult choroidal neovascularization due to age-related\\u000a macular degeneration.\\u000a \\u000a \\u000a \\u000a Methods  A consecutive interventional case series of 30 patients with active subfoveal occult choroidal neovascularization secondary\\u000a to age-related macular degeneration was followed after one

  19. Normal and degenerated rabbit nucleus pulposus cells in in vitro cultures: A biological comparison.

    PubMed

    He, Bin; Wang, Yu-Huan; Yang, Jian; Peng, Fang-Liang; Li, Feng

    2013-04-01

    This study examined the biological characteristics of normal and degenerated rabbit nucleus pulposus (NP) cells in vitro in order to provide seed cells for intervertebral disc (IVD) tissue engineering. A total of 8 adult New Zealand white rabbits underwent annulus puncture to establish models of intervertebral disc degeneration (IDD). Four weeks later, normal and degenerated NP cells were obtained. Cell morphology was observed by light and electron microscopy. Cell viability was measured by MTT assay. Cell cycle and expression of extracellular matrix (ECM)-related genes (aggrecan and type II collagen) were determined by using flow cytometry and RT-PCR respectively. The growth curve of normal NP cells showed that the cells at passage 4 tended to slowly grow on the fifth day of culture. The density of normal NP cells at passages 5 to 7 was significantly less than that of the first-passage cells 2 or 3 days after seeding (P<0.05). The degenerated NP cells at passage 3 showed slow growth at 4th day. After 5 passages, the degenerated NP cells assumed stagnant growth and the growth seemed to stop at passage 7. The MTT assay revealed that for both normal and degenerated NP cells, the absorbance (A) value at passages 4-7 was obviously decreased as compared with that at passage 1 (P<0.05). Cell cycle analysis showed that the proportion of normal NP cells at Gl phase was 65.4%±3.5%, significantly lower than that of degenerated NP cells at the same cell cycle phase with the value being 77.6%±4.8%. The degenerated NP cells were predominantly arrested at G1 phase and failed to enter S phase. The expression of type II collagen and aggrecan was significantly decreased with passaging. It was concluded that normal NP cells possessed good viability and proliferative capacity by the third passage, and they could secrete large amounts of ECM within this period. The normal NP cells may serve as seed cells for IVD tissue engineering. PMID:23592135

  20. HORMONAL CONTROL OF REVERSIBLE DEGENERATION OF FLIGHT MUSCLE IN THE COLORADO POTATO BEETLE, LEPTINOTARSA DECEMLINEATA SAY (COLEOPTERA)

    Microsoft Academic Search

    D. Stegwee; E. C. KIMMEL; J. A. DE BOER; S. HENSTRA

    1963-01-01

    In the hibernating (diapausing) Colorado potato beetle, Leptinotarsa decemlineata Say, the flight muscles show pronounced degeneration. The muscle fibrils are greatly reduced in diameter and the sarcosomes are virtually absent. Similar signs of degeneration could be produced by extirpation of the postcerebral complex of endocrine glands, the corpora cardiaca and corpora allata. Reimplantation of active postcerebral complexes resulted in a

  1. Corticobasal degeneration: a disease with widespread appearance of abnormal tau and neurofibrillary tangles, and its relation to progressive supranuclear palsy

    Microsoft Academic Search

    H. Mori; M. Nishimura; Y. Namba; M. Oda

    1994-01-01

    The neuropathological findings, including immunohistochemistry and electron microscopy, of two patients with clinical findings consistent with corticobasal degeneration (CBD) are reported. Both patients showed degeneration of the precentral cortex, the substantia nigra, the pallidum, and the thalamus. Many ballooned neurons were seen in the cerebral cortex, and argentophilic, skein-like inclusions suggesting neurofibrillary tangles (NFTs) were found in the brain stem

  2. The Cauchy problem for Tikhonov's system in the case of a multiple root of the degenerate equation

    NASA Astrophysics Data System (ADS)

    Butuzova, M. V.

    2015-01-01

    For a system of the Tikhonov type in the case of a double root of the degenerate equation, the asymptotics of the boundary-layer solution is constructed and justified. The character of the asymptotics and the algorithm for constructing it differ substantially from the classical case when the degenerate equation has a simple root.

  3. Synthetic biology and therapeutic strategies for the degenerating brain

    PubMed Central

    Agustín-Pavón, Carmen; Isalan, Mark

    2014-01-01

    Synthetic biology is an emerging engineering discipline that attempts to design and rewire biological components, so as to achieve new functions in a robust and predictable manner. The new tools and strategies provided by synthetic biology have the potential to improve therapeutics for neurodegenerative diseases. In particular, synthetic biology will help design small molecules, proteins, gene networks, and vectors to target disease-related genes. Ultimately, new intelligent delivery systems will provide targeted and sustained therapeutic benefits. New treatments will arise from combining ‘protect and repair’ strategies: the use of drug treatments, the promotion of neurotrophic factor synthesis, and gene targeting. Going beyond RNAi and artificial transcription factors, site-specific genome modification is likely to play an increasing role, especially with newly available gene editing tools such as CRISPR/Cas9 systems. Taken together, these advances will help develop safe and long-term therapies for many brain diseases in human patients. PMID:25100403

  4. Injectable microcryogels reinforced alginate encapsulation of mesenchymal stromal cells for leak-proof delivery and alleviation of canine disc degeneration.

    PubMed

    Zeng, Yang; Chen, Chun; Liu, Wei; Fu, Qinyouen; Han, Zhihua; Li, Yaqian; Feng, Siyu; Li, Xiaokang; Qi, Chunxiao; Wu, Jianhong; Wang, Deli; Corbett, Christopher; Chan, Barbara P; Ruan, Dike; Du, Yanan

    2015-08-01

    In situ crosslinked thermo-responsive hydrogel applied for minimally invasive treatment of intervertebral disc degeneration (IVDD) may not prevent extrusion of cell suspension from injection site due to high internal pressure of intervertebral disc (IVD), causing treatment failure or osteophyte formation. In this study, mesenchymal stromal cells (MSCs) were encapsulated in alginate precursor and loaded into previously developed macroporous PGEDA-derived microcryogels (PMs) to form three-dimensional (3D) microscale cellular niches, enabling non-thermo-responsive alginate hydrogel to be injectable. The PMs reinforced alginate hydrogel showed superior elasticity compared to alginate hydrogel alone and could well protect encapsulated cells through injection. Chondrogenic committed MSCs in the injectable microniches expressed higher level of nucleus pulposus (NP) cell markers compared to 2D cultured cells. In an ex vivo organ culture model, injection of MSCs-laden PMs into NP tissue prevented cell leakage, improved cell retention and survival compared to free cell injection. In canine IVDD models, alleviated degeneration was observed in MSCs-laden PMs treated group after six months which was superior to other treated groups. Our results provide in-depth demonstration of injectable alginate hydrogel reinforced by PMs as a leak-proof cell delivery system for augmented regenerative therapy of IVDD in canine models. PMID:25956851

  5. Accumulation of the Raf-1 Kinase Inhibitory Protein (Rkip) Is Associated with Cep290-mediated Photoreceptor Degeneration in Ciliopathies*

    PubMed Central

    Murga-Zamalloa, Carlos A.; Ghosh, Amiya K.; Patil, Suresh B.; Reed, Nathan A.; Chan, Lan Sze; Davuluri, Supriya; Peränen, Johan; Hurd, Toby W.; Rachel, Rivka A.; Khanna, Hemant

    2011-01-01

    Primary cilia regulate polarized protein trafficking in photoreceptors, which are dynamic and highly compartmentalized sensory neurons of retina. The ciliary protein Cep290 modulates cilia formation and is frequently mutated in syndromic and non-syndromic photoreceptor degeneration. However, the underlying mechanism of associated retinopathy is unclear. Using the Cep290 mutant mouse rd16 (retinal degeneration 16), we show that Cep290-mediated photoreceptor degeneration is associated with aberrant accumulation of its novel interacting partner Rkip (Raf-1 kinase inhibitory protein). This effect is phenocopied by morpholino-mediated depletion of cep290 in zebrafish. We further demonstrate that ectopic accumulation of Rkip leads to defective cilia formation in zebrafish and cultured cells, an effect mediated by its interaction with the ciliary GTPase Rab8A. Our data suggest that Rkip prevents cilia formation and is associated with Cep290-mediated photoreceptor degeneration. Furthermore, our results indicate that preventing accumulation of Rkip could potentially ameliorate such degeneration. PMID:21685394

  6. Altered cholesterol homeostasis in aged macrophages linked to neovascular macular degeneration

    PubMed Central

    Chen, Jing; Smith, Lois E.H.

    2013-01-01

    Abnormal lipid metabolism has been linked to age-related macular degeneration (AMD); choroidal neovascularization in late AMD commonly causes blindness. Sene et al. now demonstrate that in aged macrophages decreased ABCA1 expression, regulated by liver X receptor and miR-33, impairs export of intracellular cholesterol which promotes neovascular AMD (Sene et al., 2013). PMID:23562072

  7. Degenerate scale problem when solving Laplace's equation by BEM and its treatment

    Microsoft Academic Search

    J. T. Chen; S. R. Lin; K. H. Chen

    2005-01-01

    SUMMARY In this paper, Laplace problems are solved by using the dual boundary element method (BEM). It is found that a degenerate scale problem occurs if the conventional BEM is used. In this case, the influence matrix is rank deficient and numerical results become unstable. Both the circular and elliptical bars are studied analytically in the continuous system. In the

  8. Reduced secretion of fibulin 5 in age-related macular degeneration and cutis laxa

    Microsoft Academic Search

    Andrew J. Lotery; Dominique Baas; Caroline Ridley; Richard P. O. Jones; Caroline C. W. Klaver; Edwin Stone; Tomoyuki Nakamura; Andrew Luff; Helen Griffiths; Tao Wang; Arthur A. B. Bergen; Dorothy Trump

    2006-01-01

    Age-related macular degeneration (ARMD) is the leading cause of irreversible visual loss in the Western world, affecting approximately 25 million people worldwide. The pathogenesis is complex and missense mutations in FBLN5 have been reported in association with ARMD. We have investigated the role of fibulin 5 in ARMD by completing the first European study of the gene FBLN5 in ARMD

  9. Missense Variations in the Fibulin 5 Gene and Age-Related Macular Degeneration

    Microsoft Academic Search

    Edwin M. Stone; Terry A. Braun; Stephen R. Russell; Markus H. Kuehn; Andrew J. Lotery; Paula A. Moore; Christopher G. Eastman; Thomas L. Casavant; Val C. Sheffield

    2004-01-01

    background Age-related macular degeneration (AMD) is the most common cause of irreversible vi- sion loss in the developed world. The study of a rare mendelian form of macular degen- eration implicated fibulin genes in the pathogenesis of more common forms of this disease. We evaluated five fibulin genes in a large series of patients with AMD. methods We studied 402

  10. Infrasonic noise induces axonal degeneration of cultured neurons via a Ca²? influx pathway.

    PubMed

    Cheng, Haoran; Wang, Bing; Tang, Chi; Feng, Guodong; Zhang, Chen; Li, Ling; Lin, Tian; Du, Fang; Duan, Hong; Shi, Ming; Zhao, Gang

    2012-07-20

    Infrasound is a kind of environmental noise. It can evoke biological resonance in organismic tissues including the central nervous system (CNS), causing displacement and distortion of cellular architectures. Several studies have revealed that certain intensity infrasound can impair normal functions of the brain, but the underlying mechanisms still remain largely unknown. Growing evidence has demonstrated that axonal degeneration is responsible for a variety of CNS dysfunctions. To explore whether neuronal axons are affected under infrasonic insults, we exposed cultured hippocampal neurons to infrasound with a frequency of 16 Hz and a pressure level of 130 dB for 1h, and examined the morphological and molecular changes of neuronal axons by immunocytochemistry and Western blotting, respectively. Our results showed that infrasound exposure significantly resulted in axonal degeneration of cultured hippocampal neurons, which was relatively independent of neuronal cell death. This infrasound-induced axonal degeneration can be significantly blocked by Ca²? chelator EGTA and Rho kinase inhibitor Fasudil, but not by proteasome inhibitor MG132. Moreover, calcium imaging and RhoA activation assays revealed a great enhancement of Ca²? influx within axons and RhoA activation after infrasound exposure, respectively. Depletion of Ca²? by EGTA markedly inhibited this Ca²? influx and attenuated RhoA activation as well. Thus, our findings revealed that axonal degeneration may be one of the important mechanisms underlying infrasound-induced CNS impairment, and Ca²? influx pathway is likely implicated in the process. PMID:22626861

  11. Non-degenerate magnetic alignment of self-assembled mesophases Pawel W. Majewski* Chinedum O. Osuji

    E-print Network

    Haller, Gary L.

    to understanding the mechanisms via which self-assembly or self-assembled structures in soft materials may magnetic degeneracy that may be present in the material. The use of non-ionic mesophases is noteworthyNon-degenerate magnetic alignment of self-assembled mesophases Pawel W. Majewski* Chinedum O. Osuji

  12. Mesenteric cystic lymphangioma with myxoid degeneration: Unusual CT and MR manifestations

    Microsoft Academic Search

    S.-F. Ko; S.-H. Ng; C.-S. Shieh; J.-W. Lin; C.-C. Huang; T.-Y. Lee

    1995-01-01

    We report an unusual case of mesenteric cystic lymphangioma presenting as a large multilocular mass with a well-enhanced solid component and a central cleft, which were were pathologically correlated to the prominent stromal myxoid degeneration interspersed with abundant capillaries and the central fibrosis, respectively. The findings of computed tomography and magnetic resonance imaging are illustrated. Recognition of the multilocular configuration

  13. The Simple Non-degenerate Relativistic Gas: Statistical Properties and Brownian Motion

    E-print Network

    A. Sandoval-Villalbazo; A. Aragones-Munoz; A. L. Garcia-Perciante

    2009-01-15

    This paper shows a novel calculation of the mean square displacement of a classical Brownian particle in a relativistic thermal bath. The result is compared with the expressions obtained by other authors. Also, the thermodynamic properties of a non-degenerate simple relativistic gas are reviewed in terms of a treatment performed in velocity space.

  14. Progressive retinal degeneration and accumulation of autofluorescent lipopigments in Progranulin deficient mice.

    PubMed

    Hafler, Brian P; Klein, Zoe A; Jimmy Zhou, Z; Strittmatter, Stephen M

    2014-11-01

    Prior investigations have shown that patients with neuronal ceroid lipofuscinosis (NCL) develop neurodegeneration characterized by vision loss, motor dysfunction, seizures, and often early death. Neuropathological analysis of patients with NCL shows accumulation of intracellular autofluorescent storage material, lipopigment, throughout neurons in the central nervous system including in the retina. A recent study of a sibling pair with adult onset NCL and retinal degeneration showed linkage to the region of the progranulin (GRN) locus and a homozygous mutation was demonstrated in GRN. In particular, the sibling pair with a mutation in GRN developed retinal degeneration and optic atrophy. This locus for this form of adult onset neuronal ceroid lipofuscinosis was designated neuronal ceroid lipofuscinosis-11 (CLN11). Based on these clinical observations, we wished to determine whether Grn-null mice develop accumulation of autofluorescent particles and retinal degeneration. Retinas of both wild-type and Progranulin deficient mice were examined by immunostaining and autofluorescence. Accumulation of autofluorescent material was present in Progranulin deficient mice at 12 months. Degeneration of multiple classes of neurons including photoreceptors and retinal ganglion cells was noted in mice at 12 and 18 months. Our data shows that Grn(-/-) mice develop degenerative pathology similar to features of human CLN11. PMID:25234724

  15. Motor neuron degeneration of mice is a model of neuronal ceroid lipofuscinosis (Batten's disease)

    Microsoft Academic Search

    Roderick T. Bronson; Brian D. Lake; Susan Cook; Susanne Taylor; Muriel T. Davisson

    1993-01-01

    Pathological studies of mice homozygous for the motor neuron degeneration (Mnd) mutation show abnormalities similar to those of the human neuronal ceroid lipofuscinoses: sudanophilic, autofluorescent intraneuronal inclusions that are immunoreactive with antibodies to subunit c of mitochondrial ATP synthase. Ultrastructurally, the inclusions have the pentalaminar structure characteristic of some form of human neuronal ceroid lipofuscinosis and of canine and ovine

  16. Cytoskeleton disruption causes apoptotic degeneration of dentate granule cells in hippocampal slice cultures

    Microsoft Academic Search

    Jeong-Ah Kim; Kayo Mitsukawa; Maki K. Yamada; Nobuyoshi Nishiyama; Norio Matsuki; Yuji Ikegaya

    2002-01-01

    Colchicine, a potent microtubule-depolymerizing agent, is well known to selectively kill dentate granule cells in the hippocampal formation in vivo. Using organotypic cultures of rat entorhino-hippocampal slices, we confirmed that in vitro exposure to 1 ?M and 10 ?M of colchicine reproduced a specific degeneration of the granule cells after 24 h. Similar results were obtained with other types of

  17. A. Gonzlez-Bulnes et al.Embryo degeneration in superovulated ewes Original article

    E-print Network

    Paris-Sud XI, Université de

    A. González-Bulnes et al.Embryo degeneration in superovulated ewes Original article Influence of maternal environment on the number of transferable embryos obtained in response to superovulatory FSH-Madrid, Spain (Received 30 January 2002; accepted 10 June 2002) Abstract -- In a first experiment, embryo

  18. Protective Effects of Cannabidiol on Lesion-Induced Intervertebral Disc Degeneration

    PubMed Central

    Silveira, João W.; Issy, Ana Carolina; Castania, Vitor A.; Salmon, Carlos E. G.; Nogueira-Barbosa, Marcello H.; Guimarães, Francisco S.; Defino, Helton L. A.; Bel, Elaine Del

    2014-01-01

    Disc degeneration is a multifactorial process that involves hypoxia, inflammation, neoinnervation, accelerated catabolism, and reduction in water and glycosaminoglycan content. Cannabidiol is the main non-psychotropic component of the Cannabis sativa with protective and anti-inflammatory properties. However, possible therapeutic effects of cannabidiol on intervertebral disc degeneration have not been investigated yet. The present study investigated the effects of cannabidiol intradiscal injection in the coccygeal intervertebral disc degeneration induced by the needle puncture model using magnetic resonance imaging (MRI) and histological analyses. Disc injury was induced in the tail of male Wistar rats via a single needle puncture. The discs selected for injury were punctured percutaneously using a 21-gauge needle. MRI and histological evaluation were employed to assess the results. The effects of intradiscal injection of cannabidiol (30, 60 or 120 nmol) injected immediately after lesion were analyzed acutely (2 days) by MRI. The experimental group that received cannabidiol 120 nmol was resubmitted to MRI examination and then to histological analyses 15 days after lesion/cannabidiol injection. The needle puncture produced a significant disc injury detected both by MRI and histological analyses. Cannabidiol significantly attenuated the effects of disc injury induced by the needle puncture. Considering that cannabidiol presents an extremely safe profile and is currently being used clinically, these results suggest that this compound could be useful in the treatment of intervertebral disc degeneration. PMID:25517414

  19. PHYSICAL REVIEW A 83, 052305 (2011) Quantum error correction with degenerate codes for correlated noise

    E-print Network

    D'Ariano, Giacomo Mauro

    2011-01-01

    PHYSICAL REVIEW A 83, 052305 (2011) Quantum error correction with degenerate codes for correlated may not hold in many physical implementations of fault tolerant quantum computers, such as ion traps,3 and Paolo Perinotti2,3 1 Perimeter Institute for Theoretical Physics, 31 Caroline St. North, Waterloo

  20. Observation of an Interedge Magnetoplasmon Mode in a Degenerate Two-Dimensional Electron Gas

    E-print Network

    Hohls, Frank

    Observation of an Interedge Magnetoplasmon Mode in a Degenerate Two-Dimensional Electron Gas G-dimensional electron system (2DES) in a magnetic field travel along the edge of the sample and are called edge magnetoplasmons (EMP's). Since their first observation by Allen et al. [1] EMP's have been extensively studied

  1. Neonatal Astrocyte Damage Is Sufficient to Trigger Progressive Striatal Degeneration in a Rat Model of

    E-print Network

    Paris-Sud XI, Université de

    Neonatal Astrocyte Damage Is Sufficient to Trigger Progressive Striatal Degeneration in a Rat Model metabolic damage to astrocytes during the neonatal period may critically disrupt subsequent brainJade C and NeuN cell count. Instead, neuronal death appeared several days after GA treatment

  2. Degeneration of solventogenic Clostridium strains monitored by Fourier transform infrared spectroscopy of bacterial cells.

    PubMed

    Schuster, K C; Goodacre, R; Gapes, J R; Young, M

    2001-11-01

    Strain degeneration in solventogenic clostridia is a known problem in the technical acetone-butanol fermentation bioprocess, especially in the continuous process mode. Clostridial strain degeneration was studied by Fourier transform infrared (FT-IR) spectroscopy of the bacterial cells. Degenerative variant formation in two strains, Clostridium beijerinckii NCIMB 8052 and Clostridium species AA332, was detected spectroscopically. Colonies on solid media were sampled, or assayed directly in situ by IR microscopy. It has previously been shown that the distinctive acidogenic and solventogenic physiological phases of Clostridium acetobutylicum in liquid medium can be discriminated by FT-IR spectroscopy. This was confirmed here for C. beijerinckii NCIMB 8052. The proportion of degenerate cells in a mixed population in liquid medium could be quantified, as the spectral features change in different ways during the normal growth cycle of wild type organisms and degenerate variants in batch culture. This opens a new perspective for physiology-based process monitoring and control, especially of the continuous acetone-butanol fermentation. PMID:11781807

  3. Degenerate Ising model for atomistic simulation of crystal-melt interfaces D. Schebarchov,1

    E-print Network

    Schulze, Tim

    - dependent scaling expected from classical nucleation theory. We also analyse the equilibrium crystal with an appropriate level of coarse-graining. Phase field crystal (PFC)2 modelling is one possible way forwardDegenerate Ising model for atomistic simulation of crystal-melt interfaces D. Schebarchov,1 T. P

  4. Neurofilaments Are Nonessential to the Pathogenesis of Toxicant Induced Axonal Degeneration

    Microsoft Academic Search

    J. Derek Stone; Alan P. Peterson; Joel Eyer; T. Gregory Oblak; Dale W. Sickles

    2001-01-01

    Axonal neurofilament (NF) accumulations occur before devel- opment of symptoms and before other pathological changes among idiopathic neurodegenerative diseases and toxic neu- ropathies, suggesting a cause-effect relationship. The depen- dence of symptoms and axonal degeneration on neurofilament accumulation has been tested here in a transgenic mouse model (Eyer and Peterson, 1994) lacking axonal NFs and using two prototypic toxicant models.

  5. Ciliary Neurotrophic Factor Prevents Degeneration of Adult Rat Substantia Nigra Dopaminergic Neurons in vivo

    Microsoft Academic Search

    Theo Hagg; Silvio Varon

    1993-01-01

    We have investigated the neuroprotective effects of recombinant human ciliary neurotrophic factor (CNTF) for injured dopaminergic neurons of the adult rat substantia nigra compacta. Fourteen days after a unilateral transection of the nigrostriatal pathway two-thirds of the neurons (identified by retrograde labeling) had degenerated. In sharp contrast, 73% (a few cases, >90%) of this cell loss was prevented by continuous

  6. The Influence of Psycholinguistic Variables on Articulatory Errors in Naming in Progressive Motor Speech Degeneration

    ERIC Educational Resources Information Center

    Code, Chris; Tree, Jeremy; Ball, Martin

    2011-01-01

    We describe an analysis of speech errors on a confrontation naming task in a man with progressive speech degeneration of 10-year duration from Pick's disease. C.S. had a progressive non-fluent aphasia together with a motor speech impairment and early assessment indicated some naming impairments. There was also an absence of significant…

  7. TOPOLOGICAL ASPECTS OF THE CONFORMATIONAL STABILITY PROBLEM. PART I. DEGENERATE ELECTRONIC STATES

    Microsoft Academic Search

    Andrew D. Liehr

    1963-01-01

    : 8 8 9 2 ; enner electronic potential energy ; surfaces of symmetric polyatomic systems is derived by means of group theoretic ; and permutational symmetry principles. Degenerate penturbation theory is ; utilized to obtain an explicit analytical expression of this topography. The ; dependence of the nuclear-electronic interaction matrix elements, which occur in ; the penturbation development, on

  8. Characteristics of stem cells derived from the degenerated human intervertebral disc cartilage endplate.

    PubMed

    Liu, Lan-Tao; Huang, Bo; Li, Chang-Qing; Zhuang, Ying; Wang, Jian; Zhou, Yue

    2011-01-01

    Mesenchymal stem cells (MSCs) derived from adult tissues are an important candidate for cell-based therapies and regenerative medicine due to their multipotential differentiation capability. MSCs have been identified in many adult tissues but have not reported in the human intervertebral disc cartilage endplate (CEP). The initial purpose of this study was to determine whether MSCs exist in the degenerated human CEP. Next, the morphology, proliferation capacity, cell cycle, cell surface epitope profile and differentiation capacity of these CEP-derived stem cells (CESCs) were compared with bone-marrow MSCs (BM-MSCs). Lastly, whether CESCs are a suitable candidate for BM-MSCs was evaluated. Isolated cells from degenerated human CEP were seeded in an agarose suspension culture system to screen the proliferative cell clusters. Cell clusters were chosen and expanded in vitro and were compared with BM-MSCs derived from the same patient. The morphology, proliferation rate, cell cycle, immunophenotype and stem cell gene expression of the CESCs were similar to BM-MSCs. In addition, the CESCs could be induced into osteoblasts, adipocytes, chondrocytes, and are superior to BM-MSCs in terms of osteogenesis and chondrogenesis. This study is first to demonstrate the presence of stem cells in the human degenerated CEP. These results may improve our understanding of intervertebral disc (IVD) pathophysiology and the degeneration process, and could provide cell candidates for cell-based regenerative medicine and tissue engineering. PMID:22028847

  9. Parkinson's disease (PD) is characterized by the rela-tively selective degeneration of dopaminergic neurons in

    E-print Network

    Feng, Jian

    Parkinson's disease (PD) is characterized by the rela- tively selective degeneration- mental factors examined, the use of pesticides and herbi- cides has consistently been found to be a significant risk factor (Di Monte 2003). Recent studies in animal models, using pesticides such as rotenone

  10. A Single-Resonator GaAs FET Oscillator with Noise Degeneration

    Microsoft Academic Search

    M. J. Bianchini; J. B. Cole; R. DiBiase; Z. Galani; R. C. Wateman

    1984-01-01

    A low noise GaAs FET oscillator circuit is presented. It uses a single dielectric resonator both in the oscillator feedback circuit and as the dispersive element of a discriminator in a frequency locked loop used for noise degeneration. An FM noise level of -120 dBc\\/Hz at 10 kHz offset was measured at X-band.

  11. Yttrium oxide nanoparticles prevent photoreceptor death in a light-damage model of retinal degeneration.

    PubMed

    Mitra, Rajendra N; Merwin, Miles J; Han, Zongchao; Conley, Shannon M; Al-Ubaidi, Muayyad R; Naash, Muna I

    2014-10-01

    Photoreceptor (PR) cells are prone to accumulation of reactive oxygen species (ROS) and oxidative stress. An imbalance between the production of ROS and cellular antioxidant defenses contributes to PR degeneration and blindness in many different ocular disease states. Yttrium oxide (Y2O3) nanoparticles (NPs) are excellent free radical scavengers owing to their nonstoichiometric crystal defects. Here we utilize a murine light-stress model to test the efficacy of Y2O3 NPs (~10-14nm in diameter) in ameliorating retinal oxidative stress-associated degeneration. Our studies demonstrate that intravitreal injections of these NPs at doses ranging from 0.1 to 5.0µM 2 weeks before acute light stress protect PRs from degeneration. This protection is reflected both structurally (i.e., decreased light-associated thinning of the outer nuclear layer) and functionally (i.e., preservation of scotopic and photopic electroretinogram amplitudes). We also observe preservation of structure and function when NPs are delivered immediately after acute light stress, although the magnitude of the preservation is smaller, and only doses ranging from 1.0 to 5.0µM were effective. We show that the Y2O3 NPs are nontoxic and well tolerated after intravitreal delivery. Our results suggest that Y2O3 NPs have astonishing antioxidant benefits and, with further exploration, may be an excellent strategy for the treatment of oxidative stress associated with multiple forms of retinal degeneration. PMID:25066531

  12. Tissue Plasminogen Activator-mediated Fibrinolysis Protects Against Axonal Degeneration and Demyelination after Sciatic Nerve Injury

    Microsoft Academic Search

    Katerina Akassoglou; Keith W. Kombrinck; Jay L. Degen; Sidney Strickland

    2000-01-01

    Tissue plasminogen activator (tPA) is a serine protease that converts plasminogen to plasmin and can trigger the degradation of extracellular matrix proteins. In the nervous system, under noninflamma- tory conditions, tPA contributes to excitotoxic neuronal death, probably through degradation of laminin. To evaluate the contribution of extracellular proteolysis in inflammatory neuronal degeneration, we performed sciatic nerve injury in mice. Proteolytic

  13. Effective magnetic fields in degenerate atomic gases induced by light beams with orbital angular momenta

    Microsoft Academic Search

    G. Juzeliunas; P. Öhberg; J. Ruseckas; A. Klein

    2005-01-01

    We investigate the influence of two resonant laser beams on the mechanical properties of degenerate atomic gases. The control and probe beams of light are considered to have orbital angular momenta (OAM) and act on the three-level atoms in the electromagnetically induced transparency configuration. The theory is based on the explicit analysis of the quantum dynamics of cold atoms coupled

  14. Psychosocial Intervention for Age-Related Macular Degeneration: A Pilot Project

    ERIC Educational Resources Information Center

    Wahl, Hans-Werner; Kammerer, Annette; Holz, Frank; Miller, Daniel; Becker, Stefanie; Kaspar, Roman; Himmelsbach, Ines

    2006-01-01

    This study evaluated an emotion-focused and a problem-focused intervention designed for patients with age-related macular degeneration. It found a limited decrease in depression in the emotion-focused group and an increase in active problem orientation and in adaptation to vision loss in the problem-focused group.

  15. The Effect of an Educational Program for Persons with Macular Degeneration: A Pilot Study

    ERIC Educational Resources Information Center

    Smith, Theresa Marie; Thomas, Kimberly; Dow, Katherine

    2009-01-01

    Macular degeneration is the leading cause of vision loss in the United States for persons aged 60 and older. Compared to individuals without disabilities, individuals with low vision demonstrate a 15% to 30% higher dependence on others to perform activities of daily living. In addition, low vision can adversely affect a person's quality of life.…

  16. Assessing Susceptibility to Age-related Macular Degeneration with Proteomic and Genomic Biomarkers

    Microsoft Academic Search

    Jiayin Gu; Gayle J. T. Pauer; X. Yue; U. Narendra; G. M. Sturgill; J. Bena; X. Gu; N. S. Peachey; R. G. Salomon; S. A. Hagstrom; J. W. Crabb

    2009-01-01

    Age-related macular degeneration (AMD) is a progressive disease and major cause of severe visual loss. Toward the discovery of tools for early identification of AMD suscep- tibility, we evaluated the combined predictive capability of proteomic and genomic AMD biomarkers. We quantified plasma carboxyethylpyrrole (CEP) oxidative protein mod- ifications and CEP autoantibodies by ELISA in 916 AMD and 488 control donors.

  17. Degenerate vacua from unification of second law of thermodynamics with other laws

    Microsoft Academic Search

    Holger B. Nielsen; Masao Ninomiya

    2007-01-01

    Using our recent attempt to formulate second law of thermodynamics in a general way into a language with a probability density function, we derive degenerate vacua. Under the assumption that many coupling constants are effectively ``dynamical'' in the sense that they are or can be counted as initial state conditions, we argue in our model behind the second law that

  18. Inhibition of glycogen synthase kinase-3 by lithium correlates with reduced tauopathy and degeneration in vivo

    Microsoft Academic Search

    Wendy Noble; Emmanuel Planel; Cindy Zehr; Vicki Olm; Jordana Meyerson; Farhana Suleman; Kate Gaynor; Lili Wang; John Lafrancois; Boris Feinstein; Mark Burns; Pavan Krishnamurthy; Yi Wen; Ratan Bhat; Jada Lewis; Dennis Dickson; Karen Duff

    2005-01-01

    Neurofibrillary tangles composed of hyperphosphorylated, aggregated tau are a common pathological feature of tauopathies, including Alzheimer's disease. Abnormal phosphorylation of tau by kinases or phosphatases has been proposed as a pathogenic mechanism in tangle formation. To investigate whether kinase inhibition can reduce tauopathy and the degeneration associated with it in vivo, transgenic mice overexpressing mutant human tau were treated with

  19. The ground state of dilute Tm, Pr, and U systems is degenerate

    Microsoft Academic Search

    M. Baliña; A. A. Aligia

    1991-01-01

    The ground state of the appropriate generalization of the impurity Anderson model for valence fluctuations between two realistic configurations, is obtained in the atomic, narrow-band limit, using the Lanczos method. This limit describes the strong-coupling fixed point of renormalization group treatments for intermediate valence and Kondo impurities. The resulting ground state of Tm is highly degenerate and contains states of

  20. Congenital neuromuscular disease with type I fibre hypotrophy, ophthalmoplegia and myofibril degeneration

    Microsoft Academic Search

    H Sugie; R Hanson; G Rasmussen; M A Verity

    1982-01-01

    We report a 7-year-old boy with progressive, early onset somatic and cranial muscle weakness associated with external ophthalmoplegia, facial weakness, type I fibre hypotrophy and myofibril degeneration. We separate this condition from congenital fibre type disproportion because of the facial weakness, ophthalmoplegia, central nucleation, and lysis in type I fibres. The case, which is similar to that described by Bender