• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 18
  • 10
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 1
  • 1
  • Tagged with
  • 26
  • 26
  • 14
  • 13
  • 12
  • 12
  • 12
  • 11
  • 9
  • 8
  • 8
  • 5
  • 5
  • 4
  • 4
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Spinal motoneurons and molecules related to neurotrophic function after axon injury /

Hammarberg, Henrik, January 1900 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2000. / Härtill 7 uppsatser.
2

Functions of nogo in the development of mouse retinofugal pathway. / CUHK electronic theses & dissertations collection

January 2005 (has links)
Nogo is well established for its inhibitory action on axon regeneration in the adult central nervous system. It binds to the Nogo receptor (NgR) through an extracellular active site on the protein-Nogo-66. Although it is reported that Nogo is widely expressed in the developing brain, its exact function during development of the nervous system is unclear. / The contribution of Nogo on patterning the axon routing at the optic chiasm of mouse embryo was investigated in this thesis. Using immunocytochemical staining, Nogo protein was localized on the Miller glial cells in the retina and at the optic disk. A few migrating retinal neurons also expressed Nogo. In the chiasm, Nogo was localized exclusively on the radial glia, which generate a midline domain where turning of uncrossed axons occurs. In vitro study showed expression of NgR on retinal neurites and growth cones, and neurite outgrowth from both dorsal nasal (contralaterally projecting) and ventral temporal (ipsilaterally projecting) retina was inhibited by Nogo. In the pathway, NgR expression was regionally regulated. NgR was obvious in the optic stalk and the optic tract, but not in the chiasm. Blocking Nogo function with NEP1-40, a peptide antagonist of NgR, in brain slice culture of the pathway produced significant reduction in the uncrossed projection, but had no effect on axon crossing at the midline. Furthermore, the age related fiber arrangement in the optic tract was abolished after disturbing of Nogo function. Similar abnormalities were observed in slices treated with Nogo blocking antibody. In vitro studies showed that NEP1-40 rescued the inhibition of Nogo to the retinal neurites. The downregulation of NgR at the chiasm was supported by in vitro assays showing significant reduction of receptor expression on dorsal nasal but not ventral temporal growth cones when they encountered the chiasm, thus generating a differential inhibition to ventral temporal neurites. / These results provide evidences that Nogo is a guidance molecule during the development of CNS. Interaction of Nogo and its receptor plays important role for patterning the axon divergence in the mouse optic pathway and the age related fiber order in the optic tract. / Wang Jun. / "September 2006." / Adviser: Sun-On Chan. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1474. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 130-142). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
3

Factors influencing retinal axon pathfinding in developing mouse retinofugal pathway.

January 2008 (has links)
Chan, Chung Kit. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 98-110). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract in Chinese --- p.iv / Acknowledgements --- p.v / Table of Abbreviations --- p.vi / Table of Contents --- p.vii / Chapter Chapter 1 --- General Introduction --- p.1 / Chapter Chapter 2 --- Functions of hyaluronan in the development of retinofugal pathway / Introduction --- p.18 / Materials and Methods --- p.19 / Results --- p.23 / Discussion --- p.26 / Figures --- p.32 / Chapter Chapter 3 --- Characterization of Nogo and its receptor in retinofugal pathway using Western blot analysis / Introduction --- p.40 / Materials and Methods --- p.42 / Results --- p.50 / Discussion --- p.52 / Figures --- p.57 / Chapter Chapter 4 --- Expression patterns and functions of Sonic hedgehogin retinofugal pathway / Introduction --- p.62 / Materials and Methods --- p.64 / Results --- p.69 / Discussion --- p.76 / Figures --- p.81 / Chapter Chapter 5 --- General Discussion --- p.91 / Figures --- p.95 / References --- p.98
4

Axonal regeneration in experimental intracerebral hemorrhage / CUHK electronic theses & dissertations collection

January 2014 (has links)
Spontaneous intracerebral haemorrhage (ICH) is one of the most lethal forms of stroke and has a relatively higher morbidity in Asian people. The high disability rate of 50% in all survivors and lack of clinically effective regeneration medicine make ICH a major unanswered problem worldwide. Considerable preclinical evidence suggests that neuroprotective interventions are urgently needed to lessen the effects of this disease. To date, less preclinical researches with proven positive results have successfully translated to the clinical setting, mainly due to poor modelling, a lack of behavioural testing, inadequate experimental design and failure to consider white matter damage. According to the few previous studies, white matter is a key predictor of ICH outcomes and a potential target of recovery. The long-term axonal degeneration in rodent ICH has been ignored for decades, and almost every preclinical study has focused on mechanisms in the acute phase. Clinically ICH patients may suffer a permanent loss of brain function or long-term deficits that take years to recover from. If the preclinical researches target the long-term axon degeneration/regeneration in the chronic stage, it might help to develop successful clinical interventions for functional reconstruction and rehabilitation. / Thus, to obtain the evidence of axonal degeneration and regeneration in the chronic stage of experimental ICH, this study at first systematically assessed the histological and functional outcomes of axonal regeneration in experimental ICH from day 3 to day 56 and secondly find the effective markers and methods for investigation axons in experimental ICH models in vivo. The long-term gait disturbance of a computer-generated CatWalk system, the electrophysiological changes, axonal loss by PKC gamma (PKCγ) immunohistochemistry and axonal degeneration by Bielschowsky silver staining were examined in unilateral striatum lesioned ICH (ST-ICH) rats. As the ST-ICH model demonstrated a spontaneous functional recovery within one or two month, we further developed a modified internal capsule lesioned ICH (IC-ICH) rat model which mimic clinical conditions, and investigated whether an internal capsule lesion leads to long-term axonal damage and long lasting functional deficits. / The finding demonstrated that haematoma in striatum led to severe axonal degeneration/loss in ipsilateral medullary corticospinal tract (CST) and functional deficits in a long-term duration (1-2 months after ICH). PKCγ level was an effective marker to quantify the axonal loss in experimental ICH and it indicated a significant axonal loss on day 56 after ICH in ipsilateral CST. Bielschowsky silver staining was a useful method to illustrate the morphological changes of axonal degeneration and regeneration in longitudinal sections of CST and it clearly showed the process of axon swelling, disrupted and regenerated in 2 months’ duration after ICH. / Somatosensory evoked potentials (SSEPs) and gait analysis were valuable functional assessments to characterize the long-term behavioral deficits resulting from axonal degeneration/regeneration in experimental ICH. The decrease in electrophysiological parameter SSEP amplitudes was observed in experimental ICH. Multiple gait parameters changed after ICH and some of that such as paw print area, paw pressure, stand index, duty cycle can be used as long-term evaluating markers in chronic stage of experimental ICH. / Compared to ST-ICH, the modified IC-ICH model exhibited a relatively smaller lesion volume with consistent axonal loss/degeneration and long-lasting neurological dysfunction at 2 months after ICH. Functionally, the impairment of the mNSS, ratio of contralateral forelimb usage, four limb stand index, contralateral duty cycle and ipsilateral SSEPs amplitude remained significant in the IC-ICH model at 56 days compared with the sham group, and asymmetries in the hind paw print area of the IC-ICH model exhibited significant differences from the ST-ICH model at 56 days. Structurally, the significant loss of PKCγ in ipsilateral CST of IC-ICH and the consistent axonal degeneration with several axonal retraction bulbs and enlarged tubular space was observed at 56 days after ICH. / In summary, the data from this study systematically characterize the histological and functional outcomes (especially gait parameter and SSEPs changes) in the experimental ICH model. A modified internal capsule lesioned ICH model was developed for rats, and proved to have long lasting neurological deficits. A comprehensive understanding of the dynamic progression after experimental ICH should aid further successful clinic translation in animal ICH studies, and provide new insights into the potential biomarkers and therapeutic targets of ICH. / 原發性腦出血(ICH)是一種致死性較高的卒中類型。在亞洲人群眾發病率相對較高。高致殘率和臨床上缺乏有效的治療手段,使得腦出血成為世界範圍內的健康問題。因此需要大量的臨床前研究尋找有效的治療方法。然而,迄今為止,臨床前研究獲得的陽性結果中,只有少數被成功的轉化到臨床應用。臨床轉化存在的部分失敗,歸結於幾個主要的因素包括動物模型的不足,動物行為學實驗的不恰當使用,實驗設計的缺陷以及對白質損傷機制的忽略。有研究認為,腦白質是卒中後功能恢復的關鍵指標和潛在治療靶點。腦出血慢性期的軸索變性在齧齒類動物模型中的研究被忽視了幾十年,而幾乎所有的臨床前研究都關注於急性期的機制。而臨床上倖存的腦出血病人大多罹患永久性的腦功能損傷,往往需要數年才能恢復或者難以恢復。如果臨床前轉化實驗以腦出血後慢性期的神經軸索損傷/再生作為研究目標,也許可以找到有助於卒中後功能重建和康復的治療手段。 / 為了尋找腦出血慢性期神經軸索損傷的證據,本研究首先從組織學和功能行為學兩個方面對對實驗性腦出血後的軸索再生進行了系統的評價。並建立了有效反應慢性期神經軸索再生的一系列方法和標誌物。本研究將步態分析,電生理評價, Bielschowsky銀染和PKCγ組織學染色結合起來對腦出血後的動物模型的軸索蛻變和再生進行長期觀察。結果顯示傳統的紋狀體損傷模型在1到2個月出現自發的功能恢復。本研究進一步假設內囊出血模型可能會獲得更加持久的功能損傷,也更為接近臨床患者的情況。因此,為了更好地研究腦出血慢性期的白質損傷和類比臨床情況,本研究建立了一種改進的內囊出血大鼠模型,並用組織學和行為學方法對其長期的功能損傷進行評價。 / 研究結果顯示,位於紋狀體的血腫可以引起同側的延髓皮質脊髓束(CST)出現嚴重的慢性期退化和變性,並同時伴有神經功能損傷。PKCγ是評價實驗性腦出血後神經軸索損傷程度的有效標誌物,資料表明同側皮質脊髓束PKCγ的表達水準在ICH損傷56天后仍有顯著降低。對延髓椎體CST的Bielschowsky銀染,可以從結構上有效的反應軸索變形和再生的過程,CST縱行切片染色清楚地顯示了腦出血損傷後2個月的時間內軸索水腫、斷裂和再生的過程。 / 體感誘發電位(SSEPs)和步態分析的方法可以從功能上對腦出血後神經軸索損傷進行較為全面的評價和定量分析。單側紋狀體腦出血可以引起同側皮層SSEP波幅的降低。多個步態分析參數在腦出血後也存在明顯的變化,其中前後掌爪印面積(paw print area),爪印壓力(paw pressure),站立指數(stand index),患側肢體站立百分比(duty cycle)都可作為觀察腦出血後慢性期功能損傷和恢復的評價指標。 / 改進後的內囊腦出血模型顯示病灶體積相比較小但神經軸索的損失和神經功能障礙較為持久。從神經功能方面評判,與假手術組相比,神經功能評分(mNSS),對側前肢使用率(cylinder test),四肢站立指數(stand index),患側肢體站立百分比(duty cycle)和患側體感誘發電位波幅(SSEPs amplitude)在出血後2個月仍然顯著降低。後掌的爪印面積(print area)與紋狀體腦出血的動物比較在出血後第56天后仍有顯著差異。從軸索結構評判,內囊出血模型顯示出更為嚴重的神經軸索退變和損傷,表現為在出血後56天PKCγ蛋白表達量的持續降低,軸索斷裂結節和管狀間隙的形成。 / 綜上所述,本研究系統地分析了實驗腦出血後的組織學和功能特點,建立了一個改進的內囊腦出血大鼠模型,並證明該模型存在更為持久的神經功能障礙和神經軸索損傷。 / Liu, Yao. / Thesis Ph.D. Chinese University of Hong Kong 2014. / Includes bibliographical references (leaves 168-200). / Abstracts also in Chinese. / Title from PDF title page (viewed on 18, October, 2016). / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.
5

Axon guidance in the development of mammalian retinofugal pathways.

January 1997 (has links)
Kong Fung Wong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 59-70). / Chapter CHATPER 1 --- GENERAL INTRODUCTION --- p.1-12 / Chapter CHATPER 2 --- EXAMINATION OF THE BEHAVIOR OF GROWTH CONE IN DIFFERENT REGIONS OF THE OPTIC CHIASM / Introduction --- p.13-14 / Materials and Methods --- p.15-18 / Results --- p.19-23 / Discussion --- p.24-27 / Chapter CHATPER 3 --- STUDY OF BINOCULAR INTERACTION AFTER UNILATERAL INTRA-UTERO ENUCLEATION / Introduction --- p.28-29 / Materials and Methods --- p.30-31 / Results --- p.32-35 / Discussion --- p.36-39 / Chapter CHATPER 4 --- ISOLATION OF DIFFERENTIALLY EXPRESSED mRNA IN DIFFERENT REGIONS OF THE RETINA / Introduction --- p.40-43 / Materials and Methods --- p.44-48 / Results --- p.48-50 / Discussion --- p.51-54 / Chapter CHATPER 5 --- GENERAL DISCUSSION --- p.56-58 / REFERENCE --- p.59-70 / FIGURES / TABLES
6

Differential responses of mouse nasal and temporal retinal neurites to chondroitin sulphates: the role of protein kinase C.

January 2005 (has links)
Lam Shi Ying Joyce. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 107-114). / Abstract in English and Chinese. / Chapter CHAPTER 1 --- GENERAL INTRODUCTION --- p.1-19 / Chapter CHAPTER 2 --- EXPRESSION OF PROTEIN KINASE C (PKC) ISOFORMS IN THE VENTRAL TEMPORAL (VT) AND DORSAL NASAL (DN) RETINAL GROWTH CONES OF MOUSE EMBRYOS / INTRODUCTION --- p.20-22 / MATERIALS AND METHODS --- p.22-24 / RESULTS --- p.24-31 / DISCUSSION --- p.31-37 / FIGURES --- p.38-46 / Chapter CHAPTER 3 --- EFFECTS ON MOUSE NASAL AND TEMPORAL RETINAL NEURITES TO CHONDROITIN SULPHATES (CS) AFTER ALTERATION OF PKC ACTIVITY / INTRODUCTION --- p.47-48 / MATERIALS AND METHODS --- p.49-51 / RESULTS --- p.51-59 / DISCUSSION --- p.60-67 / FIGURES --- p.68-74 / Chapter CHAPTER 4 --- EFFECTS ON AXON ROUTING AFTER ALTERATION OF PKC ACTIVITY ON GUIDANCE OF RETINAL GANGLION CELL AXONS AT THE OPTIC CHIASM OF MOUSE EMBRYOS / INTRODUCTION --- p.75-76 / MATERIALS AND METHODS --- p.77-80 / RESULTS --- p.80-89 / DISCUSSION --- p.89-95 / FIGURES --- p.96-103 / Chapter CHAPTER 5 --- GENERAL CONCLUSION --- p.104-106 / REFERENCES --- p.107-114
7

Investigations of factors that control retinal axon growth during mouse optic pathway development. / CUHK electronic theses & dissertations collection

January 2010 (has links)
Chiasm cells, which include glia and neurons, are generated early before any retinal axon arrives at the midline of the mouse ventral diencephalon. These cells have been shown to affect retinal axon growth and patterning in the optic chiasm. In this study, we used EdU (5-ethyny1-2'-deoxyuridine) for birthdating these chiasm cells, aiming to find out when these cells are generated; then we tried to trace their fates at later stages of development. EdU injection at embryonic day (E) 9.5 to El 1 labeled a number of chiasmatic neurons and radial glial cells at E13, which were immunoreactive for SSEA-1 and RC2, respectively. After colocalization studies, we found that most of these neurons were born as early as E9.5, while a large number of radial glial cells were born as from El 1. Both E9.5-born chiasmatic neurons and Ell-born radial glia decreased by E14-E16; the radial glia even disappeared finally from the midline. Furthermore, we found that some chiasmatic neurons underwent apoptotic cell death as from El 4, and that the radial glia likely differentiated into other cell types after finishing their retinal axon guidance mission at the midline. So it is reasonable that some of the earliest born chiasm cells disappear during development. / During development, retinal ganglion cell axons grow from the eye to the ventral diencephalon, where axons from the two eyes converge and segregate into crossed and uncrossed projections, forming the optic chiasm. This pattern is critical for binocular vision. Although significant progress has been obtained over the past decades, how retinal axon growth and guidance are regulated at the chiasm is largely unknown. Our research will focus on those problems. / In the last part of this thesis, we investigated the retinal axon pathway in the ventral diencephalon of the Sox10Dom mutant embryos and gamma-crystallin mutant embryos. Our findings indicate that Sox10 may not contribute to axon guidance in the developing optic pathway whereas gammaA-crystallin may only play a role in the later uncrossed axons. / N-methyl-D-aspartate (NMDA) receptor is one of the ionotropic glutamate receptors, which are important in synaptic plasticity, apart from implications in dendritic spine remodeling, neurite outgrowth, elongation and branching and glutamate neurotoxicity. There are several subtypes of NMDA receptor channel subunits, NR1, NR2A-D, NR3A&B. The functional diversity of NMDA receptor resides in the different assembly of subunits. In this study, we used RT-PCR to analyze the mRNA expression of all the NMDA receptor subunits in mouse embryos. After that we chose the NR1, NR2B and NR3A antibodies to investigate NMDA receptor subunit expression in the optic pathway during mouse optic pathway development. Using immunohistochemistry, we found that NR1, NR2B and NR3A were expressed in the mouse retina and optic pathway as from E13 when the optic chiasm is forming. Expression of the NMDA receptor subunits were found in the inner cell layers and along retinal axons. Colocalization studies showed that NR1, NR2B and NR3A were localized on the ganglion cells and their axons. In the ventral diencephalon, these subunits were expressed extensively, but NR1 and NR3A were particularly strong along the optic nerve and optic tract. Furthermore, to identify the function of NMDA receptor during optic chiasm development, we cultured E14 retinal explants on laminin and poly-D-ornithine in the presence of the NMDA receptor antagonists MK-801 or Dextrorphan-D-tartrate. These two antagonists can significantly inhibit the retinal axon outgrowth, suggesting that the NMDA receptor promotes retinal axon outgrowth in the retinofugal pathway during optic chiasm development. / Li, Jia. / Adviser: Chan Sun On. / Source: Dissertation Abstracts International, Volume: 73-02, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 145-158). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
8

Regulations of axon routings at the optic chiasm of mouse embryos.

January 1999 (has links)
Chung Kit Ying. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 90-104). / Abstracts in English and Chinese. / Chapter Chapter 1 --- General Introduction --- p.1-22 / Chapter Chapter 2 --- Expression of Chondroitin Sulfate Proteoglycans (CSPGs) in the Chiasm of Mouse Embryos / Introduction --- p.23-24 / Materials and Methods --- p.25 -27 / Results --- p.28-33 / Discussion --- p.34-40 / Figures --- p.41-45 / Chapter Chapter 3 --- Effects on Axon Routing after Removal of Chondroitin Sulfate Proteoglycans by Enzymatic Digestion / Introduction --- p.46 -47 / Materials and Methods --- p.48 -50 / Results --- p.57 / Discussion --- p.57-61 / Figures --- p.62-66 / Chapter Chapter 4 --- Immediate Effects of Prenatal Monocular Enucleation on the Cellular and Molecular Environment in the Development of Retinofugal Pathway / Introduction --- p.67-69 / Materials and Methods --- p.70-72 / Results --- p.73.77 / Discussion --- p.78-82 / Figures --- p.83-86 / Chapter Chapter 5 --- General Conclusion --- p.87-89 / References --- p.90 -104
9

Axon patterning in the mouse retinofugal pathway.

January 2002 (has links)
Leung Kin Mei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 106-125). / Abstracts in English and Chinese. / Chapter CHAPTER 1 --- GENERAL INTRODUCTION --- p.1-11 / Chapter CHAPTER 2 --- ENZYMATIC REMOVAL OF CHONDROITIN SULFATES ABOLISHES THE AGE-RELATED ORDER IN THE OPTIC TRACT OF MOUSE EMBRYOS / INTRODUCTION --- p.12-13 / MATERIALS AND METHODS --- p.13-18 / RESULTS --- p.18-24 / DISCUSSION --- p.24-29 / FIGURES --- p.30-39 / Chapter CHAPTER 3 --- EXPRESSION OF PHOSPHACAN AND NEUROCAN IN THE DEVELOPING MOUSE RETINOFUGAL PATHWAY / INTRODUCTION --- p.40-42 / MATERIALS AND METHODS --- p.42-43 / RESULTS --- p.44-49 / DISCUSSION --- p.49-55 / FIGURES --- p.56-61 / Chapter CHAPTER 4 --- HEPARAN SULFATE PROTEOGLYCAN EXPRESSION IN THE OPTIC CHIASM OF MOUSE EMBRYOS / INTRODUCTION --- p.62-63 / MATERIALS AND METHODS --- p.63-65 / RESULTS --- p.66-70 / DISCUSSION --- p.70-76 / FIGURES --- p.77-82 / Chapter CHAPTER 5 --- EXPRESSION OF NEURAL CELL ADHESION MOLECULES IN THE CHIASM OF MOUSE EMBRYOS / INTRODUCTION --- p.83-85 / MATERIALS AND METHODS --- p.85-88 / RESULTS --- p.88-92 / DISCUSSION --- p.92.95 / FIGURES --- p.96-102 / Chapter CHAPTER 6 --- GERNEAL CONCLUSION --- p.103-105 / REFERENCES --- p.106-125
10

Molecules signaling axon growth during development of mouse optic pathway. / CUHK electronic theses & dissertations collection

January 2004 (has links)
Hao Yanli. / "July 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (p. 113-134). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Page generated in 0.0566 seconds