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  • 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.
41

Branched chain amino acids attenuate major pathologies in mouse models of retinal degeneration and glaucoma / 分岐鎖アミノ酸は網膜変性や緑内障のモデルマウスにおいて変性の進行を抑制する

Hasegawa, Tomoko 25 March 2019 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第21651号 / 医博第4457号 / 新制||医||1034(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 髙橋 良輔, 教授 伊達 洋至, 教授 松原 和夫 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
42

Light-Independent Pathology of Rhodopsin Mislocalization

Ropelewski, Philip Edward 02 June 2020 (has links)
No description available.
43

Retrospective Cohort Study to Examine Disease Progression in Retinitis pigmentosa Patients Seen at the University of Ottawa Eye Institute

Kandakji, Lynn 15 January 2024 (has links)
Retinitis pigmentosa (RP) is the most common form of inherited retinal degeneration, heterogenous in its clinical presentation and genetic cause. Understanding the short-term disease mechanisms is pivotal for the development of new therapies. Upcoming clinical trials will take genotype-agnostic approaches; therefore, a comprehensive analysis of progression that encompasses many genetic factors will be needed. In this 10-year retrospective cohort study, rates of progression were measured, structurally and functionally, in 85 RP patients seen at the Ottawa Eye Institute. Parameters examined were the ellipsoid zone (EZ) length on an optical coherence tomography (OCT) image, Humphrey and Goldmann visual fields (VF), and full-field and multifocal electroretinograms (ERGs). RP is revealed to have a 1st order exponential decay pattern of loss, with mean rates of decline of 7.65 %/year for ellipsoid zone (EZ) length, 6.35%/year, 4.39%/year, and 1.57%/year for the Humphrey VF 30-2, 24-2, and 10-2 mean deviation (MD) respectively, and 5.22%/year, 7.77%/year, 6.77%/year, 6.80%/year, and 12.45%/year for Goldmann V4e, III4e, I4e, I3e, and I2e isopter lengths, respectively. In cases where different diagnostic tests were conducted within 3 months of each other, the data was analysed to determine if there was a positive correlation between the diagnostic tests. Ellipsoid zone length and Humphrey 24-2 mean deviation exhibited the strongest association with a coefficient of 0.99. The study reveals structural and functional changes in advanced retinitis pigmentosa and presents a protocol for assessing short-term progression.
44

Towards photoreceptor replacement in the mammalian retina – Identification of factors influencing donor cell integration

Postel, Kai 08 May 2014 (has links) (PDF)
Vision impairment and blindness are in industrialized countries primarily caused by the degeneration of the retina, the light sensing tissue inside the eye. The degeneration, occurring in diseases like age-related macular degeneration (AMD) or retinitis pigmentosa (RP), can be caused by environmental factors as well as genetic defects and thus shows diverse pathologies. In all conditions, the light detecting photoreceptors (rods and/or cones) are dying caused by either direct photoreceptor damage or as a secondary effect following degeneration of supporting cells. Although promising treatment approaches are currently under investigation, up to date it is not possible to cure these diseases. Amongst these therapeutic strategies, pre-clinical studies evaluating the replacement of degenerated cells by transplantation of new photoreceptors demonstrated promising results. First studies conducted the specific enrichment and transplantation of primary photoreceptors derived from postnatal mice and their sufficient integration and differentiation into mature photoreceptors in wild-type as well as degenerated mouse retinae. Recent experiments additionally proved the recovery of some dim-light vision after transplantation in mice lacking night sight. The in vitro differentiation of whole eye cups containing photoreceptors, out of human or mouse ES or iPS cells, peaked in the transplantation of ES-derived photoreceptors into wild-type as well as degenerated mice and the integration and maturation of these cells. These observations are encouraging, but prior to a save implementation of this strategy into a clinical routine, several further hurdles need to be challenged. Collection of photoreceptors out of whole retinal tissues prior to transplantation was shown to be an important step to reach high integration rates. Additionally, transplantation of photoreceptors derived from stem cells comprises the risk of tumor formation after transplantation and thus also requires depletion of inadvertent cells. Therefore, we established the enrichment of photoreceptors using the cell surface marker dependent method magnetic-activated cell sorting (MACS). For identification of suitable target-specific surface markers, we characterized young transplantable mouse photoreceptors using microarray analysis and screened their transcriptome. Amongst others, ecto-5´nucleotidase (Nt5e, termed CD73) was identified being a rod photoreceptor specific cell surface protein. Thus, we enriched young photoreceptors with CD73-dependent MACS with sufficient purity and transplanted these cells into the subretinal space of wild-type mice. In contrast to unsorted retinal cells, enriched photoreceptors integrated in significantly higher number into the host retina, proving that MACS is a suitable alternative for specific photoreceptor enrichment. Testing other proteins, identified as photoreceptor specific, for MACS suitability and the translation of this approach to photoreceptors, derived from mouse as well as human iPS or ES cells, should be the focus of consecutive investigations. The integration of grafted cells into the retina is a complex process dependent on a variety of influencing factors. Transplantation experiments in aging wild-type mice and a rod-depleted mouse model, containing a retina composed of cone and cone-like photoreceptors, indicated that the activation of Müller glia cells facilitates integration of transplanted photoreceptors. Besides that, reduced outer limiting membrane (OLM) integrity, increased subretinal graft distribution or reduced retinal cell density are further suggested as potential cell engraftment enhancers. These factors might open up important possibilities of host retina manipulation to increase cell integration rates. Although retinal transplantation experiments were in addition to mice also performed using pigs or rats as hosts, the transplantation of enriched single photoreceptors, following the protocols successfully established in mice, has not been performed in other species. Nevertheless, transferring this technique is important and would allow better predictions for future application in human patients. Therefore, we transferred our protocol, using CD73 based MACS, to the rat and successfully enriched rat photoreceptors with sufficient purity. We subsequently transplanted these cells into the subretinal space of rats as well as mice and observed limited integration capacity of grafted cells. Only few transplanted rat photoreceptors were localized in the rat retina, lacking proper photoreceptor morphology. Especially regarding a perspective clinical application in humans, these data are remarkable. They imply the question, whether low integration in rat represents a general problem and might thus also be relevant for treatment in humans, or whether the rat retina forms just an exception. Thus, further detailed analysis of the cellular and molecular mechanisms underlying the integration process of transplanted photoreceptors represent an essential prerequisite for the development of a safe and efficient therapy, aiming to treat retinal degenerative diseases characterized by photoreceptor loss. / Degenerationserkrankungen der Netzhaut (Retina) sind in Industrieländern die Hauptursache für verminderte Sehfähigkeit und Blindheit. Sowohl Umweltfaktoren als auch vererbte Mutationen können Defekte wie altersbedingte Makuladegeneration (AMD) oder Retinitis pigmentosa (RP) auslösen und führen zu einem sehr variablen Krankheitsbild. Eine Gemeinsamkeit aller Formen ist das Absterben der lichtdetektierenden Fotorezeptoren (Stäbchen und/oder Zapfen). Dieses kann entweder durch direkte Schädigung, oder als Sekundäreffekt nach Degeneration der unterstützenden Zellen erfolgen. Obwohl im Moment vielversprechende Behandlungsansätze untersucht werden, ist es zurzeit nicht möglich, retinale Degenerationserkrankungen dieser Art zu heilen. Ein erfolgversprechender Ansatz könnte jedoch der Ersatz der degenerierten Zellen durch transplantierte Fotorezeptoren sein. Erste Studien demonstrierten die spezifische Anreicherung von primären Fotorezeptoren aus der Netzhaut neugeborener Mäuse und deren subretinale Transplantation in Wildtyp-Mäuse und Mausmodelle mit retinaler Degeneration. Die transplantierten Zellen integrierten in die Empfängernetzhaut und entwickelten sich in ausgereifte Fotorezeptoren und konnten unter anderem bei nachtblinden Mäusen die Sehfähigkeit bei Dunkelheit verbessern. Die Differenzierung von humanen oder murinen ES- und iPS-Zellen in vitro in vollständige Retinae und die Transplantation daraus gewonnener Fotorezeptoren in Mäuse, bilden vorläufig den Höhepunkt dieser Entwicklung. Obwohl die Fortschritte der jüngsten Vergangenheit beeindruckend sind, sollten vor der sicheren und effektiven Anwendung einer retinalen Zellersatztherapie als therapeutische Maßnahme beim Menschen noch einige wissenschaftliche Fragestellungen beantwortet werden. Studien zeigen, dass Zellpopulationen, die direkt aus der Spendernetzhaut entnommen und transplantiert wurden, auf Grund ihrer Heterogenität in geringeren Zahlen in die Empfängerretina einwandern als angereicherte Fotorezeptoren. Zusätzlich besteht bei unsortierten Zellen, die aus Stammzellpopulationen gewonnen wurden, das Risiko einer Tumorbildung. Daher haben wir die magnetisch-aktivierte Zellsortierung (MACS) zur Anreicherung junger Fotorezeptoren etabliert. Die dabei benötigten, für Fotorezeptoren spezifischen, Oberflächenproteine wurden mit Hilfe von Microarray-Analysen des Transkriptoms junger Stäbchen von Mäusen identifiziert. Dabei wurde unter anderem die 5\'-Nukleotidase (Nt5e, CD73) entdeckt, die uns die erfolgreiche Anreicherung junger Mausfotorezeptoren mit Hilfe von CD73-vermitteltem MACS erlaubte. Die Transplantation dieser angereicherten Zellpopulation in die Netzhaut von Empfängertieren resultierte in einer signifikant erhöhten Integrationsrate im Vergleich zu nicht-angereicherten retinalen Zellen. Die Überprüfung der Nutzbarkeit weiterer identifizierter Oberflächenproteine zur Zellanreicherung bzw. die Übertragung der etablierten Protokolle zur Zellsortierung und Transplantation auf Fotorezeptoren aus ES- und iPS-Zellkulturen, sollten im Fokus nachfolgender Experimente stehen. Die Integration transplantierter Zellen in die Empfängernetzhaut ist ein komplexer Prozess und von unterschiedlichen Einflussfaktoren abhängig. Durch Transplantationsexperimente in alternden Wildtyp-Mäusen und einem Mausmodell, dessen Fotorezeptorschicht keine Stäbchen und stattdessen nur Zapfen und zapfenähnlichen Fotorezeptoren aufweist, konnte gezeigt werden, dass vor allem die Aktivierung von Müllerzellen die Integrationsrate der Fotorezeptoren erhöht. Neben dieser sogenannten Gliose werden weitere Faktoren, wie die reduzierte Stabilität der äußeren Grenzmembran, die flächenmäßig größere Verteilung der transplantierten Zellen im subretinalen Raum oder die reduzierte Dichte der Zellen in der äußeren Körnerschicht, als potentielle integrationsfördernde Komponenten in Betracht gezogen. Diese bilden interessante Schwerpunkte für weitere Forschungen, um eine ausreichende Zellintegration durch Manipulation der Empfängernetzhaut, auch in der klinischen Anwendung, zu erreichen. Obwohl Transplantationsexperimente zusätzlich zur Maus auch in anderen Empfängerspezies, wie Ratten und Schweinen, durchgeführt wurden, liegen bis jetzt keine Studien vor, die die in der Maus erfolgreich etablierten Protokolle der Zellanreicherung und Transplantation von Fotorezeptor-Suspensionen in diesen Spezies reproduzierte. Der Transfer dieser Technik und eine Generalisierung der Anwendbarkeit eines Fotorezeptorersatzes durch Transplantation in verschiedenen Säugetierarten geben jedoch wichtige Hinweise für eine mögliche Translation dieser Technologie für klinische Anwendungen. Deshalb haben wir unser bereits an der Maus getestetes Protokoll auf die Ratte übertragen und erfolgreich Fotorezeptoren der Ratte mit Hilfe von CD73-vermitteltem MACS angereichert. Nach deren Transplantation in die Netzhaut von Ratten und Mäusen zeigten die Rattenfotorezeptoren aber eine stark verminderte Integrationsfähigkeit und das Fehlen einer reifen Fotorezeptormorphologie. Speziell in Hinsicht auf eine zukünftige klinische Anwendung sind diese Ergebnisse relevant, da sie die Frage aufwerfen, ob die mangelnde Integration in der Ratte ein generelles Problem darstellt und daher auch beim Menschen zu erwarten ist, oder ob sie nur eine Ausnahme im Rattenmodell bildet. Aus diesem Grund bildet die weitere Erforschung der zellulären und molekularen Mechanismen der Integration transplantierter Fotorezeptoren eine wichtige Grundlage für die Entwicklung einer sicheren und effizienten Therapie mit dem Ziel, degenerative Netzhauterkrankungen zu heilen.
45

Avaliação do genótipo de pacientes com Síndrome de Usher do Centro de Referência em Oftalmologia da Universidade Federal de Goiás / Evaluation of patients with genotype Reference Center Ophthalmology, Federal University of Goiás Usher Syndrome

Cruvinel Filho, Ricardo Campos 16 December 2014 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2016-08-02T13:12:16Z No. of bitstreams: 2 Dissertação - Ricardo Campos Cruvinel Filho - 2014.pdf: 8513057 bytes, checksum: e42a2106d7e7abda6b1ee9d65068229d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-08-02T13:28:23Z (GMT) No. of bitstreams: 2 Dissertação - Ricardo Campos Cruvinel Filho - 2014.pdf: 8513057 bytes, checksum: e42a2106d7e7abda6b1ee9d65068229d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-08-02T13:28:23Z (GMT). No. of bitstreams: 2 Dissertação - Ricardo Campos Cruvinel Filho - 2014.pdf: 8513057 bytes, checksum: e42a2106d7e7abda6b1ee9d65068229d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2014-12-16 / Cross-sectional study conducted at the Center of Reference in Ophthalmology UFG in conjunction with Oregon Health and Science University and the Brazilian Center for Eye Surgery (CBCO). To evaluate the genotype of patients with Usher syndrome of Reference Center for Ophthalmology, Federal University of Goias (UFG-CEROF). Patients clinically diagnosed with SU underwent complete ophthalmic examination, Goldmann manual kinetic perimetry, audiometry and subsequent collection of peripheral blood chromosomal microarray for sequencing. We examined 19 patients with clinical suspicion of SU with a mean age at first visit was 42.5 years (± 12.2) and a slight predominance of males (52.63%). The most prevalent subtype in clinical diagnosis of type I disease (68.4%). The visual acuity measured on the day of the exam for eye examination was 20/92 on the Snellen chart. Examinations audiometry showed hearing loss in all patients ranging from moderate in 12.5% of patients, deep (56.25%) and severe (31.25%). In 36.8% of patients analyzed, we found at least two mutations in the same gene, and of these, 21% were heterozygous mutations, and 15.8% homozygous. The homozygous mutations, which were of the type no sense, occurred in the gene CLRN1 whose patients had a previous diagnosis of USH 2. Met 26.31% of the sample analyzed in heterozygous. Of these, two patients showed mutations in the MYO7A gene (40%), both with clinical suspicion of USH 1. For the proposed methodology, we found no disease-causing mutations in 79% of the sample analyzed. Following the proposed methodology, the authors were able to determine the mutation in seven patients of nineteen patients inclued in this study. Of these, three patients were diagnosed with homozygous mutations in gene CLRN1, and had previous clinical diagnosis of type 2. Two patients had heterozygous mutations in gene MYO7A, both with previous clinical diagnosis of type 1. / Estudo transversal, desenvolvido no Centro de Referência em Oftalmologia da UFG em conjunto com a Oregon Health and Science University e Centro Brasileiro de Cirurgia de Olhos (CBCO), que teve como objetivo avaliar o genótipo de pacientes com síndrome de Usher do Centro de Referência em Oftalmologia da Universidade Federal de Goias (CEROF-UFG). Pacientes clinicamente diagnosticados com SU foram submetidos a exame oftalmológico completo, perimetria cinética manual de Goldmann, audiometria e posterior coleta de sangue periférico para sequenciamento cromossômico por microarray. Foram examinados 19 pacientes com diagnostico clínico de SU com média de idade na primeira consulta de 42,5 anos (± 12,2) e pequena predominância do sexo masculino (52,63%). O subtipo mais prevalente no diagnóstico clínico foi do tipo I da doença (68,4%). A acuidade visual média medida no dia do exame por olho examinado foi de 20/92 na escala de Snellen. Os exames audiométricos mostraram perda de audição em todos pacientes variando de moderada em 12,5% dos pacientes, profunda (56,25%) e severa (31,25%). Em 36,8% dos pacientes analisados, encontraram-se ao menos duas mutações em um mesmo gene, sendo que destes, 21% eram mutações heterozigotas e, 15,8% homozigotas. As mutações homozigotas, as quais eram do tipo sem senso, ocorreram no gene CLRN1, cujos pacientes tinham o diagnóstico clínico prévio de USH 2. Encontrou-se 26,31% da amostra analisada em heterozigose. Desses, dois pacientes mostraram mutações para o gene MYO7A (40%), ambos com suspeita clínica de USH 1. Pela metodologia proposta, não foram encontradas mutações causadoras de doença em 79% da amostra analisada. Dos 19 pacientes incluídos no presente estudo os autores conseguiram determinar a mutação de sete deles segundo a metodologia proposta. Desses, três pacientes foram diagnosticados com mutações homozigoticas todas no gene CLRN1 e possuíam diagnostico clinico prévio de SU tipo 2. Dois pacientes apresentaram mutações heterozigóticas para o gene MYO7A, ambos com diagnostico clinico prévio de SU tipo 1 e um paciente apresentou mutação heterozigótica para o gene ALMS1 que apresentava diagnostico clinico de SU tipo 1.
46

Bothnia dystrophy, a clinical, genetical and electrophysiological study

Burstedt, Marie January 2003 (has links)
A high frequency of retinitis pigmentosa (RP) is found in Northern Sweden. In an inventory of autosomal recessive RP patients in Västerbotten County, a great number of cases with a unique phenotype was noticed, denoted Bothnia Dystrophy (BD). The aim of the study was to describe the phenotype, to determine the chromosomal location, and to identify the gene. Patients typically show night blindness from early childhood. Symptoms of defect macular function with a decrease of visual acuity can appear in early adulthood. The retinal fundus shows irregular white spots in a central, and parafoveal pattern along the arcades. Centrally areolar maculopathy develops and round circular atrophies are observed in the periphery. The disease was shown to be associated with a missense mutation in the RLBP1 gene resulting in an amino acid substitution (R234W) in the cellular retinaldehyde-binding protein (CRALBP). The R234W mutation was found in a homozygous state in 61 patients affected with BD. Ten patients were heterozygous for the R234W mutation, and presented a similar phenotype. No additional mutations in the coding sequence or exon-intron junctions were found. CRALBP is localised in retinal pigment epithelium (RPE), and Müller cells of the retina. In the RPE, CRALBP functions as a carrier protein for endogenous retinoids. Dark adaptometry and electrophysiologic testing showed an initial loss of rod function followed by a progressive reduction of the cone responses in older ages. A compromised rod function, dysfunction of the Müller cells, and indications of a disturbed function of the inner retina were found. With prolonged dark adaptation, a gradual increase in retinal sensitivity to light and an improvement of the ERG components occurred. The findings indicate a prolonged synthesis of photopigments, retardation of the visual process in the retinal pigment epithelium and a loss of retinal cells probably starting at a relative early age in BD. To evaluate the subjective visual function in BD patients, a battery of objective tests of visual function and composite score of the 25-item NEI-Visual Function Questionnaire (VFQ-25) were analyzed. We found that weighted distance logMAR visual acuity (WVA), had the strongest association with subjective visual function, and that there was a considerable loss of subjective and objective visual function with increasing age in BD patients. The prevalence of BD is as high as 1:3600 in Västerbotten County. The possibility that recycling of retinoids localized in the RPE might be impaired in BD might give future therapeutic possibilities. Due to the large and clinically well-characterized set of patients with this disease, they constitute a suitable study group.
47

Développement de modèles in vitro de rétinites pigmentaires à partir de cellules souches pluripotentes humaines / Development of in vitro models of retinitis pigmentosa using patient-specific pluripotent stem cells

Terray, Angélique 21 September 2015 (has links)
Les rétinites pigmentaires (RP) sont des pathologies rétiniennes cécitantes d'origine génétique caractérisées par une perte des photorécepteurs. Nous avons ciblé des formes de RP autosomique dominante consécutives à des mutations dans le gène du pigment visuel de la RHODOPSINE, du facteur d'épissage PRPF31 et du facteur de transcription impliqué dans le développement des photorécepteurs NR2E3. Les fibroblastes, issus de biopsies de peau de patients, ont été reprogrammés en cellules iPS par une technique dite non intégrative. Après stabilisation des cellules iPS, nous avons vérifié leur propriété de pluripotence et l'absence d'anomalies caryotypiques.Les cellules iPS porteuses d'une mutation sur le gène RHODOPSINE ont été différenciées dans le lignage des photorécepteurs. Nos résultats montrent que les photorécepteurs porteurs de la mutation P347L du le gène RHODOPSINE récapitulent la dégénérescence observée chez les patients.Nous montrons que les cellules de l'épithélium pigmentaire rétinien (EPR) dérivées de cellules iPS porteuses de la mutation Cys294X du gène PRPF31 présentent des problèmes d'adhésion cellulaire due à l'absence de lame basale. Leur activité de phagocytose est alors perturbée, suggérant qu'un dysfonctionnement de l'EPR pourrait être à la base de la RP causée par la mutation Cys294X du gène PRPF31. Les modèles développés nous ont permis de mieux comprendre les processus à la base de la pathogénèse de certaines RP. Ces modèles associés à des protocoles de criblage, pourraient permettre d'évaluer l'efficacité et la toxicité de nouvelles molécules pharmacologiques, mais également être utilisés pour valider des approches de thérapie génique. / Retinitis pigmentosa (RP) is an inherited retinal diseases characterized by a loss of photoreceptors. We focused specific forms of autosomal dominant RP with mutations in the rod visual pigment RHODOPSIN, the ubiquitous splicing factor PRPF31 and the transcription factor involved in the development of photoreceptors NR2E3. Fibroblasts from skin biopsies of patients were reprogrammed into iPS cells by a non-integrative approach. After stabilization of iPS cell lines, we verified their pluripotency property and the absence of karyotype abnormalities. Based on the retinal differentiation protocol, iPS cells carrying a mutation in the RHODOPSIN gene have been differentiated in the photoreceptor lineage. Our results showed that the photoreceptors expressing the mutated form of RHODOPSIN summarizing the process of degeneration observed in RP patients. We show that retinal pigment epithelium (RPE) cells derived from iPS cells carrying a mutation in the PRPF31 gene lack basal membranes and have cell adhesion disorders. Consequently, their phagocytic activity is disturbed, suggesting that a malfunction of the RPE could be the primary step of the development of RP caused by mutation Cys294X in the PRPF31 gene. The models developed from specific-patient iPS cells have enabled us to better understand the processes underlying the pathogenesis of some RP. These models associated with screening protocols could be used to evaluate the efficacy and toxicity of new pharmacologic compounds but also used to validate new gene therapy approaches.
48

Etude des corrélations anatomiques et fonctionnelles au cours de la rétinopathie pigmentaire : identification et validation de nouveaux marqueurs prédictifs / Study of the anatomical and functional correlations in retinitis pigmentosa : identification and validation of new predictive markers

Azoulay-Sebban, Line 29 October 2015 (has links)
Introduction : Les rétinopathies pigmentaires (RP) sont caractérisées par une grande hétérogénéité clinique et génétique rendant difficile la fiabilité du pronostic évolutif. Les nouvelles techniques d’évaluation laissent envisager la découverte de nouveaux marqueurs prédictifs palliant à ce problème. Matériel et méthode : Les patients sont majeurs et atteints de RP type bâtonnets-cônes. Le projet de thèse comprend l’étude de la qualité de vie (QDV), l’identification de nouveaux marqueurs prédictifs et l’examination du traitement par optogénétique. Résultats : 1) Un diamètre du champ visuel inférieur à 20° et une acuité visuelle inférieure à 0.3 représentent un seuil fonctionnel de dégradation de la QDV et de l’état émotionnel du patient. 2) L’intérêt des examens ophtalmologiques varie selon le stade de progression de la maladie. L’OCT est un examen révélé important à chaque stade de la RP. Le fond d’œil autofluorescent n’est pertinent que lorsqu’un anneau hyper-autofluorescent (HAF) est présent. 3) L’Optique Adaptative (OA), un potentiel nouveau marqueur innovant mais non-standardisé, révèle une diminution de la densité en cônes dans toutes les zones de l’anneau HAF. 4) Le traitement par optogénétique ne peut être proposé qu’à une minorité de patients avec une RP avancée ayant encore des cônes résiduels centraux. Conclusion : Les examens de suivi anatomo-fonctionnels à préconiser varient selon l’évolution de la RP. L’OA fournit de riches espoirs pour le suivi des patients RP par la visualisation des structures fines de la rétine. Les données de QDV et d’état émotionnel, sont indispensables pour mieux appréhender la maladie et avérer de l’efficacité d’un traitement. / Introduction: Retinitis pigmentosa (RP) are characterized by a great clinical and genetic heterogeneity making difficult any reliable evolutionary prognosis. New assessment techniques presage discovering new predictive markers overcoming this problem. Materials and Methods: RP patients are over 18 years old and have been diagnosed with rod-cone dystrophy. This thesis studies the impacts on quality of life (QOL), new predictive markers and optogenetics treatments. Results: 1) A diameter of less than 20° visual fields combined with a visual acuity of less than 0.3 set a functional level of degradation of QOL. 2) The benefits of ophthalmic examinations at follow-up RPs vary with stages of the disease. However the OCT exam has been proven beneficial throughout all PR stages; the autofluorescent funduscopy is only relevant when a hyper-autofluorescent (HAF) ring is present in the retina. 3) Adaptive Optics (AO), a new innovative marker not yet standardized, reveals a decrease in the cones density in all areas of the HAF ring. 4) Optogenetics treatments, based on a neuromodulation method, can only be offered to a minority of patients with advanced RP still having central residual cones. Conclusion: The anatomical and functional follow-up examinations to advocate to RP patients vary according to the stages of RP. OA provides rich hopes for monitoring RP patients by viewing the fine structures of the retina. Besides, data on QOL and emotional states are essential to better understand the RP disease and prove the effectiveness of a treatment.
49

Uso intravítreo de fração mononuclear da medula óssea (FMMO) contendo células CD34+ em pacientes portadores de degeneração hereditária da retina - retinose pigmentar (RP) / Intravitreal use of bone marrow mononuclear fraction (BMMF) containing CD34+ cells in patients with hereditary retinal degeneration - retinitis pigmentosa (RP)

Arcieri, Rafael Saran 25 May 2018 (has links)
Introdução: A Retinose Pigmentar (RP) é uma doença hereditária da retina, caracterizada por perda da função visual, principalmente devido à degeneração dos fotorreceptores (bastonetes e cones). Objetivo: Avaliar os efeitos de uma única injeção intravítrea de fração mononuclear de células da medula óssea (FMMO) CD34+ em pacientes portadores de RP. Métodos: Ensaio clínico aberto, não randomizado, prospectivo, observador mascarado, no qual 20 pacientes, portadores de RP, com boa fixação ao exame de campo visual, foram incluídos. Única injeção intravítrea (IIV) de FMMO foi aplicada em apenas um dos olhos de cada paciente, enquanto que os olhos contralaterais serviram como controle e foram submetidos à injeção simulada. As avaliações incluíram: melhor acuidade visual corrigida (MAVC); campo visual estático - estratégia 30-2 (Octopus 900); microperimetria (MAIA - Center Vue) para avaliar estabilidade de fixação e sensibilidade macular; eletrorretinografia de campo total (ERG) e multifocal (mfERG) - padrão da ISCEV usando aparelho Espion E2 (Diagnosys LLC) e tomografia de coerência óptica (OCT). Os exames foram realizados antes da injeção e 4, 16, 32 e 48 semanas após. Resultados: Não houve diferença significativa na MAVC durante o seguimento. A diferença entre MAVC medida após 48 semanas e a basal foi de -0,04 ? 0,02 logMAR nos olhos tratados frente a -0,03 ? 0,01 logMAR nos controles (p=0,3898). A melhora da sensibilidade macular foi discretamente maior nos olhos com FMMO: 1,0 ? 0,5 dB do que nos olhos contralaterais: 0,2 ? 0,5 dB, mas sem significância estatística (p=0,0569). Não se observou mudança na estabilidade de fixação. A perda de desvio médio (MD) do campo visual dos olhos tratados (0,33 ? 0,70 dB) foi discretamente menor do que nos olhos controle (1,12 ? 0,58 dB) (p=0,0761). Nenhuma diferença significativa foi observada nas amplitudes e latências das respostas eletrorretinográficas durante o período avaliado. Não se verificou nenhuma complicação e nem efeito colateral após a injeção. Conclusão: A aplicação intravítrea de FMMO contendo células CD34+ mostrou-se segura em pacientes com RP. Observou-se, ainda, discreta melhora na sensibilidade macular, mas esta não foi significativa estatisticamente. Estudos futuros são necessários para esclarecer o potencial uso dessas células em distrofias retinianas. / Introduction: Retinitis pigmentosa (RP) is a hereditary disease of the retina, characterized by loss of visual function, mainly due to degeneration of the photoreceptors (rods and cones). Objective: To evaluate the effects of a single intravitreal injection of bone marrow mononuclear fraction (BMMF) containing CD34+ cells in patients with RP. Methods: Open trial, non-randomized, prospective, masked observer, in which 20 patients with RP with good fixation in visual field examination were included. Single intravitreal injection of BMMF was performed in only one eye of each patient, while the contralateral eyes served as control and underwent shaw injection. Evaluations included: best corrected visual acuity (BCVA); static visual field - strategy 30-2 (Octopus 900); microperimetry (MAIA - Center Vue) to evaluate fixation stability and macular sensitivity; full-field (ERG) and multifocal (mfERG) electroretinograms according to the ISCEV using Espion E2 (Diagnosys LLC) and optical coherence tomography (OCT). The exams were performed before the injection and 4, 16, 32 and 48 weeks after. Results: There was no significant difference in BCVA during follow-up. The difference measured in BCVA between 48 weeks and baseline was 0.04 ? 0.02 logMAR in treated eyes versus -0.03 ? 0.01 logMAR in controls (p=0.3898). The improvement in macular sensitivity was slightly higher in BMMF eyes: 1.0 ? 0.5 dB than in contralateral eyes: 0.2 ? 0.5 dB, but without statistical significance (p=0.0569). No change in fixation stability was observed. The mean deviation loss (MD) of the visual field in treated eyes (0.33 ? 0.70 dB) was slightly lower than in the control eyes (1.12 ? 0.58 dB) (p=0.0761). No significant difference was observed evaluating amplitudes and latencies of ERG and mfERG responses during the follow-up. No complications or side effects were observed after the injection. Conclusion: The intravitreal injection of BMMF containing CD34 + cells was shown to be safe in patients with RP. There was still a slight improvement in macular sensitivity, but this was not statistically significant. Future studies are needed to clarify the potential use of these cells in retinal dystrophies.
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Segmentation and Contrasting in Different Biomedical Imaging Applications

Tayyab, Muhammad 02 February 2012 (has links) (PDF)
Advancement in Image Acquisition Equipment and progress in Image Processing Methods have brought the mathematicians and computer scientists into areas which are of huge importance for physicians and biologists. Early diagnosis of diseases like blindness, cancer and digestive problems have been areas of interest in medicine. Development of Laser Photon Microscopy and other advanced equipment already provides a good idea of very interesting characteristics of the object being viewed. Still certain images are not suitable to extract sufficient information out of that image. Image Processing methods have been providing good support to provide useful information about the objects of interest in these biological images. Fast computational methods allow complete analysis, in a very short time, of a series of images, providing a reasonably good idea about the desired characteristics. The thesis covers application of these methods in 3 series of images intended for 3 different types of diagnosis or inference. Firstly, Images of RP-mutated retina were treated for detection of rods, where there were no cones present. The software was able to detect and count the number of cones in each frame. Secondly, a gastrulation process in drosophila was studied to observe any mitosis and results were consistent with recent research. Finally, another series of images were treated where biological cells were observed to undergo mitosis. The source was a video from a photon laser microscope. In this video, objects of interest were biological cells. The idea was to track the cells if they undergo mitosis. Cell position, spacing and sometimes contour of the cell membrane are broadly the factors limiting the accuracy in this video. Appropriate method of image enhancement and segmentation were chosen to develop a computational method to observe this mitosis. Cases where human intervention may be required have been proposed to eliminate any false inference.

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