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Takahashi H, Suzuki H, Bertinshaw J, Bette S, Mühle C, Nuss J, Dinnebier R, Yaresko A, Khaliullin G, Gretarsson H, Takayama T, Takagi H, Keimer B. Nonmagnetic J=0 State and Spin-Orbit Excitations in K_{2}RuCl_{6}. Phys Rev Lett 2021; 127:227201. [PMID: 34889637 DOI: 10.1103/physrevlett.127.227201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 10/18/2021] [Indexed: 06/13/2023]
Abstract
Spin-orbit Mott insulators composed of t_{2g}^{4} transition metal ions may host excitonic magnetism due to the condensation of spin-orbital J=1 triplons. Prior experiments suggest that the 4d antiferromagnet Ca_{2}RuO_{4} embodies this notion, but a J=0 nonmagnetic state as a basis of the excitonic picture remains to be confirmed. We use Ru L_{3}-edge resonant inelastic x-ray scattering to reveal archetypal J multiplets with a J=0 ground state in the cubic compound K_{2}RuCl_{6}, which are well described within the LS-coupling scheme. This result highlights the critical role of unquenched orbital moments in 4d-electron compounds and calls for investigations of quantum criticality and excitonic magnetism on various crystal lattices.
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Affiliation(s)
- H Takahashi
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
- Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - H Suzuki
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - J Bertinshaw
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - S Bette
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - C Mühle
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - J Nuss
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - R Dinnebier
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - A Yaresko
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - G Khaliullin
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - H Gretarsson
- Deutsches Elektronen-Synchrotron DESY, Notkestrstraße 85, D-22607 Hamburg, Germany
| | - T Takayama
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
- Institute for Functional Matter and Quantum Technologies, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - H Takagi
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
- Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
- Institute for Functional Matter and Quantum Technologies, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - B Keimer
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
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Lenz B, Mühle C, Braun B, Weinland C, Bouna-Pyrrou P, Behrens J, Kubis S, Mikolaiczik K, Muschler MR, Saigali S, Sibach M, Tanovska P, Huber SE, Hoppe U, Eichler A, Heinrich H, Moll GH, Engel A, Goecke TW, Beckmann MW, Fasching PA, Müller CP, Kornhuber J. Prenatal and adult androgen activities in alcohol dependence. Acta Psychiatr Scand 2017; 136:96-107. [PMID: 28383757 DOI: 10.1111/acps.12725] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/01/2017] [Indexed: 12/23/2022]
Abstract
OBJECTIVE Alcohol dependence is more prevalent in men than in women. The evidence for how prenatal and adult androgens influence alcohol dependence is limited. We investigated the effects of prenatal and adult androgen activity on alcohol dependence. Moreover, we studied how the behaviours of pregnant women affect their children's prenatal androgen load. METHOD We quantified prenatal androgen markers (e.g., second-to-fourth finger length ratio [2D : 4D]) and blood androgens in 200 early-abstinent alcohol-dependent in-patients and 240 controls (2013-2015, including a 12-month follow-up). We also surveyed 134 women during pregnancy (2005-2007) and measured the 2D : 4D of their children (2013-2016). RESULTS The prenatal androgen loads were higher in the male alcohol-dependent patients compared to the controls (lower 2D : 4D, P = 0.004) and correlated positively with the patients' liver transaminase activities (P < 0.001) and alcohol withdrawal severity (P = 0.019). Higher prenatal androgen loads and increasing androgen levels during withdrawal predicted earlier and more frequent 12-month hospital readmission in alcohol-dependent patients (P < 0.005). Moreover, stress levels (P = 0.002), alcohol (P = 0.010) and tobacco consumption (P = 0.017), and lifetime stressors (P = 0.019) of women during pregnancy related positively to their children's prenatal androgen loads (lower 2D : 4D). CONCLUSION Androgen activities in alcohol-dependent patients and behaviours of pregnant women represent novel preventive and therapeutic targets of alcohol dependence.
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Affiliation(s)
- B Lenz
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - C Mühle
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - B Braun
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - C Weinland
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - P Bouna-Pyrrou
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - J Behrens
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - S Kubis
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - K Mikolaiczik
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - M-R Muschler
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - S Saigali
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - M Sibach
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - P Tanovska
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - S E Huber
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - U Hoppe
- Department of Audiology, ENT Clinic, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - A Eichler
- Department of Child and Adolescent Mental Health, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - H Heinrich
- Department of Child and Adolescent Mental Health, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany.,kbo-Heckscher-Klinikum, Munich, Germany
| | - G H Moll
- Department of Child and Adolescent Mental Health, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - A Engel
- Department of Gynecology and Obstetrics, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - T W Goecke
- Department of Gynecology and Obstetrics, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany.,Department of Perinatal Medicine and Obstetrics, University Hospital RWTH Aachen, Aachen, Germany
| | - M W Beckmann
- Department of Gynecology and Obstetrics, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - P A Fasching
- Department of Gynecology and Obstetrics, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - C P Müller
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - J Kornhuber
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
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Rhein C, Mühle C, Richter-Schmidinger T, Reichel M, Alexopoulos A, Kornhuber J. Neuroanatomical correlates of cognitive performance in healthy young adults: the role of basal ganglia volume. Pharmacopsychiatry 2013. [DOI: 10.1055/s-0033-1353334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Santamaria-Perez D, Morales-Garcia A, Martinez-Garcia D, Garcia-Domene B, Mühle C, Jansen M. Structural phase transitions on AgCuS stromeyerite mineral under compression. Inorg Chem 2013; 52:355-61. [PMID: 23244465 DOI: 10.1021/ic302116b] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The structural behavior of mineral Stromeyerite, AgCuS, has been studied by means of angle-dispersive X-ray diffraction measurements up to 13 GPa and ab initio total-energy calculations. Two high-pressure phase transitions are found at 1.4 and 5.7 GPa, from the initial distorted Ni(2)In-type phase (AuRbS-type, RP, space group Cmc2(1)) through an anti-PbClF-type phase (HP1, space group P4/nmm) to a monoclinic distortion of this latter phase (HP2, space group P2(1)/m). The collapse of the metal-metal interatomic distances at the RP-HP1 transition suggests a stronger metallic behavior of the high-pressure phase. The compressibility of the lattice parameters and the equation of state of the first pressure-induced phase have been experimentally determined. First-principles calculations present an overall agreement with the experimental results in terms of the high-pressure sequence and provide chemical insight into the AgCuS behavior under hydrostatic pressure.
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Affiliation(s)
- D Santamaria-Perez
- Departamento de Química-Física I, Universidad Complutense de Madrid, Avenida Complutense s/n, 28040 Madrid, Spain.
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Abstract
Despite the high prevalence and devastating impact of psychiatric disorders, little is known about their etiopathology. In this review, we provide an overview on the participation of sphingolipids and enzymes responsible for their metabolism in mechanisms underlying psychiatric disorders. We focus on the pathway from sphingomyelin to proapoptotic ceramide and the subsequent metabolism of ceramide to sphingosine, which is in turn phosphorylated to yield anti-apoptotic sphingosine-1-phosphate (S1P).The sphingomyelinase/ceramide system has been linked to effects of reactive oxygen species and proinflammatory cytokines in the central nervous system as well as to synaptic transmission. Compared to ubiquitously expressed acid sphingomyelinase, acid and neutral ceramidase and neutral sphingomyelinase are highly active in brain regions. Depressed patients show elevated plasma ceramide levels and increased activities of acid sphingomyelinase which is functionally inhibited by many anti-depressive drugs. Exposure to alcohol is associated with an activation of acid and neutral sphingomyelinase observed in cell culture, mouse models and in alcohol-dependent patients and with increased concentrations of ceramide in various organs.Levels of sphingomyelin and ceramide are altered in erythrocytes and post-mortem brain tissues of schizophrenic patients in addition to changes in expression patterns for serine palmitoyltransferase and acid ceramidase leading to impaired myelination. After induction of anxiety-like behavior in animal models, higher serum levels of S1P were reported to lead to neurodegeneration. Correspondingly, S1P infusion appeared to increase anxiety-like behavior. Significantly upregulated levels of the endogenous ceramide catabolite N,N-dimethylsphingosine were observed in rat models of allodynia. Conversely, rats injected intrathecally with N,N-dimethylsphingosine developed mechanical allodynia. Moreover, S1P has been implicated in spinal nociceptive processing.The increasing interest in lipidomics and improved analytical methods led to growing insight into the connection between psychiatric and neurological disorders and sphingolipid metabolism and may once provide new targets and strategies for therapeutic intervention.
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Affiliation(s)
- C Mühle
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University of Erlangen, Erlangen, Germany
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Klinge J, Khrenov AV, Saenko EL, Schneider H, Mühle C. Spectrum of antigenic FVIII domains recognized by antibodies from haemophiliacs. Hamostaseologie 2008. [DOI: 10.1055/s-0037-1617124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
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Mühle C, Steichen-Gersdorf E, Strom T, Kapelari K, Schneider H. Contiguous Gene Syndrome aufgrund einer 3,4 Mb-Deletion in Xp21 mit synchroner Manifestation klinischer Symptome bei monozygoten Zwillingen. Z Geburtshilfe Neonatol 2008. [DOI: 10.1055/s-2008-1079005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Mühle C, Schröder J, Oldenburg J, Schneider H. Aufdeckung verschiedenartiger Mutationsmechanismen bei Hämophiliepatienten mit Deletionen im FVIII-Gen mittels Bruchpunktanalyse. Z Geburtshilfe Neonatol 2007. [DOI: 10.1055/s-2007-983192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Mühle C, Neuner A, Park J, Pacho F, Jiang Q, Waddington SN, Schneider H. Evaluierung einer pränatalen Gentherapiestrategie für die Behandlung des Morbus Herlitz. Z Geburtshilfe Neonatol 2007. [DOI: 10.1055/s-2007-983062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Mühle C, Neuner A, Park J, Pacho F, Jiang Q, Waddington SN, Schneider H. Evaluation of prenatal intra-amniotic LAMB3 gene delivery in a mouse model of Herlitz disease. Gene Ther 2006; 13:1665-76. [PMID: 16871230 DOI: 10.1038/sj.gt.3302832] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Revised: 06/01/2006] [Accepted: 06/24/2006] [Indexed: 01/13/2023]
Abstract
Prenatal gene therapy has been considered for Herlitz junctional epidermolysis bullosa (H-JEB), a lethal genodermatosis caused by the absence of any of the three subunits of laminin-5, resulting from birth in widespread blistering and erosions of skin and mucosae. To investigate this strategy in an animal model, adenovirus type 5- and adeno-associated virus (AAV) type 2-derived vectors carrying a beta-galactosidase reporter gene or LAMB3 cDNA encoding the beta3 chain of laminin-5 were generated, tested for stability in amniotic fluid and evaluated in vitro on murine H-JEB keratinocytes, and in vivo by prenatal injection into the amniotic cavities of laminin-5 beta3-deficient mice. The different vectors were administered individually or combined at maximum doses on day 14 post coitum. Adenoviral vectors infected preferentially the foetal epidermis, whereas AAV delivered the transgene mainly to mucous membranes of the airways and the upper digestive tract. The LAMB3 transgene was expressed in target epithelia of newborn laminin-5 beta3-deficient mice, and the transgenic beta3 chain was shown to assemble with its endogenous partner chains, resulting in detectable amounts of laminin-5 in the basement membranes of skin and mucosae and in a lower extent of tissue separation in the skin. However, only combined delivery of the two vector types led to a minor increase of the life span of H-JEB mice. Failure to rescue diseased animals was, at least in part, due to abandonment of any conspicuous pup by the heterozygous mother. This is the first study of a prenatal gene therapy approach to a heritable blistering disorder. Although our findings indicate that prenatal combined administration of adenoviral and adeno-associated LAMB3 vectors provides therapeutic benefit to H-JEB mice, this animal model appears unsuitable for long-term investigations of the therapeutic concept.
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Affiliation(s)
- C Mühle
- University of Erlangen-Nuernberg, Children's Hospital, Erlangen 91054, Germany
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Mühle C, Neuner A, Park J, Pacho F, Jiang Q, Waddington S, Schneider H. Evaluation of prenatal intra-amniotic LAMB3 gene delivery by adenoviral and AAV vectors in a mouse model of Herlitz junctional epidermolysis bullosa. Z Geburtshilfe Neonatol 2006. [DOI: 10.1055/s-2006-946206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Jakob M, Mühle C, Park J, Frank S, Waddington S, Schneider H. No evidence for germ-line transmission following prenatal and early postnatal AAV-mediated gene delivery. Z Geburtshilfe Neonatol 2006. [DOI: 10.1055/s-2006-946205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Mühle C, Neuner A, Park J, Pacho F, Jiang Q, Waddington S, Schneider H. Evaluation of prenatal intra-amniotic LAMB3 gene delivery by adenoviral and AAV vectors in a mouse model of Herlitz junctional epidermolysis bullosa. Z Geburtshilfe Neonatol 2006. [DOI: 10.1055/s-2006-943291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Jakob M, Mühle C, Park J, Frank S, Waddington S, Schneider H. No evidence for germ-line transmission following prenatal and early postnatal AAV-mediated gene delivery. Z Geburtshilfe Neonatol 2006. [DOI: 10.1055/s-2006-943290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Gemming S, Seifert G, Mühle C, Jansen M, Albu-Yaron A, Arad T, Tenne R. Electron microscopy, spectroscopy, and first-principles calculations of Cs2O. J SOLID STATE CHEM 2005. [DOI: 10.1016/j.jssc.2004.09.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Schneider H, Groves M, Mühle C, Reynolds PN, Knight A, Themis M, Carvajal J, Scaravilli F, Curiel DT, Fairweather NF, Coutelle C. Retargeting of adenoviral vectors to neurons using the Hc fragment of tetanus toxin. Gene Ther 2000; 7:1584-92. [PMID: 11021597 DOI: 10.1038/sj.gt.3301270] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The Hc fragment of tetanus toxin (Hc) retains the specific nerve cell binding and transport properties of the holotoxin, but lacks any toxicity. We are investigating the potential for utilising its neurotropism for targeted gene delivery to the central nervous system. Previously we reported the use of Hc-polylysine conjugates for selective gene transfer into neuronal cells in vitro. However, as attempts to apply these constructs in vivo were not successful, we have extended these studies to modification of the tropism of adenoviral vectors. Either Hc-polylysine conjugates or the Fab fragment of a neutralising anti-knob antibody covalently bound to Hc were attached to the virus. Infection of neuronal and non-neuronal cell lines with retargeted virus showed highly increased neuronal cell selectivity, but no significant enhancement of gene delivery into these cells. High concentrations of free Hc blocked the infectivity of the retargeted vector efficiently. Intramuscular injection of retargeted virus into mouse tongues resulted in selective gene transfer to the neurons of the hypoglossal nucleus, where no pathological changes were observed. As differentiated neurons do not undergo cell division, appropriate vectors carrying a thymidine kinase gene, which allows selective elimination of dividing cells, may be exploitable for the treatment of tumours of the central nervous system. The demonstrated suitability of the Hc fragment of tetanus toxin as targeting moiety for viral vectors also indicates a potential for gene therapy of inherited neurodegenerative diseases such as spinal muscular atrophy.
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Affiliation(s)
- H Schneider
- Division of Biomedical Sciences, Imperial College School of Medicine, London, UK
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Chao TI, Grosche J, Friedrich KJ, Biedermann B, Francke M, Pannicke T, Reichelt W, Wulst M, Mühle C, Pritz-Hohmeier S, Kuhrt H, Faude F, Drommer W, Kasper M, Buse E, Reichenbach A. Comparative studies on mammalian Müller (retinal glial) cells. J Neurocytol 1997; 26:439-54. [PMID: 9306243 DOI: 10.1023/a:1018525222826] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Müller cells from 22 mammalian species were subjected to morphological and electrophysiological studies. In the 'midperiphery' of retinae immunocytochemically labeled for vimentin, estimates of Müller cell densities per unit retinal surface area, and of neuron-to-(Müller) glia indices were performed. Müller cell densities were strikingly similar among the species studied (around 8000-11,000 mm-2) with the extremes of the horse (< or = 5000 mm-2) and the tree shrew (> or = 20,000 mm-2). By contrast, the number of neurons per Müller cell varied widely, being clustered at 6-8 (in retinae with many cones), at about 16, and at up to more than 30 (in strongly rod-dominated retinae). Isolated Müller cell volumes were estimated morphometrically, and cell surface areas were calculated from membrane capacities. Müller cells isolated from thick vascularized retinae (carnivores, rats, mice, ungulates) were longer and thinner, and had smaller volumes but higher surface-to-volume ratios than cells from thin paurangiotic (i.e. with blood vessels only near the optic disc) or avascular retinae (rabbits, guinea pigs, horses, zebras). In whole-cell voltage-clamp studies, Müller cells from all mammals studied displayed two dominant K+ conductances, inwardly rectifying currents and delayed rectifier currents. TTX-sensitive Na+ currents were recorded only in some species. Based on these data, the following hypotheses are presented, (a) neuron-to-(Müller) glia indices are determined by precursor cell proliferation rather than by metabolic demands; (b) Müller cell volumes depend on available space rather than on the number of supported neurons; and (c) it follows that, the specific metabolic activities of Müller cells must differ greatly between species, a difference that may contribute to distinct patterns of retinal vascularization.
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Affiliation(s)
- T I Chao
- Paul Flechsig Institute for Brain Research, Leipzig University, Germany
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