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- Anderson, Malin, et al.
(författare)
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Structure and locomotion of adult in vitro regenerated spiral ganglion growth cones : a study using video microscopy and SEM
- 2006
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Ingår i: Hearing Research. - : Elsevier BV. - 0378-5955 .- 1878-5891. ; 215:1-2, s. 97-107
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Tidskriftsartikel (refereegranskat)abstract
- Neuronal development and neurite regeneration depends on the locomotion and navigation of nerve growth cones (GCs). There are few detailed descriptions of the GC function and structure in the adult auditory system. In this study, GCs of adult dissociated and cultured spiral ganglion (SG) neurons were analyzed in vitro utilizing combined high resolution scanning electron microscopy (SEM) and time lapse video microscopy (TLVM). Axon kinesis was assessed on planar substratum with growth factors BDNF, NT-3 and GDNF. At the nano-scale level, lamellipodial abdomen of the expanding GC was found to be decorated with short surface specializations, which at TLVM were considered to be related to their crawling capacity. Filopodia were devoid of these surface structures, supporting its generally described sensory role. Microspikes appearing on lamellipodia and axons, showed circular adhesions, which at TLVM were found to provide anchorage of the navigating and turning axon. Neurons and GCs expressed the DCC-receptor for the guidance molecule netrin-1. Asymmetric ligand-based stimulation initiated turning responses suggest that this attractant cue influences steering of GC in adult regenerating auditory neurites. Hopefully, these findings may be used for ensuing tentative navigation of spiral ganglion neurons to induce regenerative processes in the human ear.
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| 2. |
- Boström, Marja, et al.
(författare)
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Neural network and "Ganglion" formations in vitro : a video microscopy and scanning electron microscopy study on adult cultured spiral ganglion cells.
- 2007
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Ingår i: Otology and Neurotology. - 1531-7129 .- 1537-4505. ; 28:8, s. 1109-1119
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Tidskriftsartikel (refereegranskat)abstract
- Hypothesis: To analyze if adult-dissociated spiral ganglion cells may be propagated in vitro for later use in transplantation models to form integrated neural networks. Background: Hearing loss is often associated with primary or secondary spiral ganglion cell degeneration. New strategies for cell repair and tissue engineering warrants further elucidation of the regenerative capacity of the auditory nerve. Methods: We used in vitro/in video microscopy in combination with immunocytochemistry and field emission scanning electron microscopy to analyze neural development and network formation from dissociated adult guinea pig spiral ganglion cells. Cells were cultured in serum-free medium and in the presence of brain-derived neurotrophic factor, neurotrophin 3, and glia cell line-derived neurotrophic factor for up to 8 weeks. Results: Time-lapse video microscopy and scanning electron microscopy exposed the propagation of auditory neurons and the role of neural growth cones in axon locomotion, fasciculation, and nuclear migration, often ensuing in cell congregation (ganglion-like formations) during network formation. Axons were sometimes ensheathed by adjoining S-100/glia fibrillary acidic protein-expressing cells. A few expanding neurons were nestin positive and sometimes incorporated the markers of proliferating cells Ki67 and 5'-bromo-2-deoxyuridine. Neurons expressed the markers and transcription factors for neural development neurogenin 1, neurogenic differentiation factor 1, Brn3a, and GATA binding protein 3, as well as the neural markers beta-III tubulin, NeuN, and neurofilament 160 during this process. Conclusion: This method of culturing and expanding spiral ganglion neurons in vitro may be useful in further studies of cell transplantation models aiming to restore the injured inner ear.
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| 7. |
- Kaplan, Lew, et al.
(författare)
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Retinal regions shape human and murine Müller cell proteome profile and functionality
- 2023
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Ingår i: GLIA. - : Wiley. - 0894-1491 .- 1098-1136. ; 71:2, s. 391-414
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Tidskriftsartikel (refereegranskat)abstract
- The human macula is a highly specialized retinal region with pit-like morphology and rich in cones. How Müller cells, the principal glial cell type in the retina, are adapted to this environment is still poorly understood. We compared proteomic data from cone- and rod-rich retinae from human and mice and identified different expression profiles of cone- and rod-associated Müller cells that converged on pathways representing extracellular matrix and cell adhesion. In particular, epiplakin (EPPK1), which is thought to play a role in intermediate filament organization, was highly expressed in macular Müller cells. Furthermore, EPPK1 knockout in a human Müller cell-derived cell line led to a decrease in traction forces as well as to changes in cell size, shape, and filopodia characteristics. We here identified EPPK1 as a central molecular player in the region-specific architecture of the human retina, which likely enables specific functions under the immense mechanical loads in vivo.
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| 8. |
- Liu, Wei, et al.
(författare)
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Macromolecular organization and fine structure of the human basilar membrane - RELEVANCE for cochlear implantation
- 2015
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Ingår i: Cell and Tissue Research. - : Springer Science and Business Media LLC. - 0302-766X .- 1432-0878. ; 360:2, s. 245-262
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Cochlear micromechanics and frequency tuning depend on the macromolecular organization of the basilar membrane (BM), which is still unclear in man. Novel techniques in cochlear implantation (CI) motivate further analyses of the BM. Materials and methods Normal cochleae from patients undergoing removal of life-threatening petro-clival meningioma and an autopsy specimen from a normal human were used. Laser-confocal microscopy, high resolution scanning (SEM) and transmission electronmicroscopy (TEM) were carried out in combination. In addition, one human temporal bone was decellularized and investigated by SEM. Results The human BM consisted in four separate layers: (1) epithelial basement membrane positive for laminin-beta 2 andcollagen IV, (2) BM Bproper boolean AND composed of radial fibers expressing collagen II and XI, (3) layer of collagen IV and (4) tympanic covering layer (TCL) expressing collagen IV, fibronectin and integrin. BM thickness varied both radially and longitudinally (mean 0.55-1.16 mu m). BM was thinnest near the OHC region and laterally. Conclusions There are several important similarities and differences between the morphology of the BM in humans and animals. Unlike in animals, it does not contain a distinct pars tecta (arcuate) and pectinata. Its width increases and thickness decreases as it travels apically in the cochlea. Findings show that the human BM is thinnest and probably most vibration-sensitive at the outer pillar feet/Deiter cells at the OHCs. The inner pillar and IHCs seem situated on a fairly rigid part of the BM. The gradient design of the BM suggests that its vulnerability increases apical wards when performing hearing preservation CI surgery.
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| 9. |
- Liu, Wei, et al.
(författare)
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Molecular composition and distribution of gap junctions in the sensory epithelium of the human cochlea a super-resolution structured illumination microscopy (SR-SIM) study
- 2017
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Ingår i: Upsala Journal of Medical Sciences. - : Uppsala Medical Society. - 0300-9734 .- 2000-1967. ; 122:3, s. 160-170
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Tidskriftsartikel (refereegranskat)abstract
- Background: Mutations in the GJB2 gene, which encodes the Connexin26 (Cx26) protein, are the most common cause of childhood hearing loss in American and European populations. The cochlea contains a gap junction (GJ) network in the sensory epithelium and two connective tissue networks in the lateral wall and spiral limbus. The syncytia contain the GJ proteins beta 2 (GJB2/Cx26) and beta 6 (GJB6/Cx30). Our knowledge of their expression in humans is insufficient due to the limited availability of tissue. Here, we sought to establish the molecular arrangement of GJs in the epithelial network of the human cochlea using surgically obtained samples. Methods: We analyzed Cx26 and Cx30 expression in GJ networks in well-preserved adult human auditory sensory epithelium using confocal, electron, and super -resolution structured illumination microscopy (SR-SIM). Results: Cx30 plaques (<5 mu m) dominated, while Cx26 plaques were subtle and appeared as 'mini junctions' (2-300 nm). 3-D volume rendering of Z-stacks and orthogonal projections from single optical sections suggested that the GJs are homomeric/homotypic and consist of assemblies of identical GJs composed of either Cx26 or Cx30. Occasionally, the two protein types were co-expressed, suggesting functional cooperation. Conclusions: Establishing the molecular composition and distribution of the GJ networks in the human cochlea may increase our understanding of the pathophysiology of Cx-related hearing loss. This information may also assist in developing future strategies to treat genetic hearing loss.
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| 10. |
- Rask-Andersen, Helge, et al.
(författare)
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Perilymph/modiolar communication routes in the human cochlea
- 2006
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Ingår i: Ear and Hearing. - : Ovid Technologies (Wolters Kluwer Health). - 0196-0202 .- 1538-4667. ; 27:5, s. 457-465
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To analyze communication routes between perilymph spaces and the modiolus in the human cochlea. Such pathways are of potential importance with regard to local inner ear drug delivery and pharmacokinetics. Design: We analyzed the surface structure of the human cochlea, using high-resolution scanning electron microscopy (SEW in macerated and freshly obtained specimens together with light microscopy of celloidin-embedded temporal bones. Results: Combined SEM and fight microscopy showed that perilymph and fluid spaces in the modiolar periphery form a common system. The modiolar wall of the scala vestibuli and tympani in the first and second turn is porous, forming a perilymphatic communication route to the perivascular and perineural spaces in the modiolus. A "perimodiolar lymph" or fluid space can he identified in the modiolar periphery. It communicates through a trabecular meshwork of porous membrane and web of connective tissue with the perilymph. The thin mesothelial cell sheets showed pores and displayed signs of vesicular activity. Conclusions: This canalicular system may play a role in the circulation of perilymph in the human cochlea. We suggest that this system may represent an important fluid communication route between modiolus and perilymph and may represent a pathway for future drug and cell-based therapy to the inner ear.
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