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Sistema de medidas de áreas de úlceras de córnea e acompanhamento de suas evoluções para ser utilizado em hospitais / System for measuring corneal ulcers areas and their evolution monitoring to be used in hospitalsCaio Chiaradia 02 October 1998 (has links)
Foi desenvolvido um sistema inédito para diagnóstico e acompanhamento de Doenças Oculares Externas, particularmente de úlceras de córnea e que foi implementado num Hospital-Escola para uso diário. As úlceras de córnea, até então, eram avaliadas de forma subjetiva e qualitativa, estimando-se a extensão da área afetada. O indicativo de evolução do quadro clínico é basicamente a alteração da área afetada. Com o intuito de se poder avaliar a evolução desta patologia de forma quantitativa e padronizada, foi desenvolvido o presente sistema. O sistema consistiu em acoplar a uma Lâmpada de Fenda (biomicroscópio ocular) um divisor de feixes e um sistema ótico, no caminho ótico onde os feixes da Lâmpada de Fenda são paralelos, de forma que a imagem proporcionada nas oculares da Lâmpada de Fenda é simultaneamente proporcionada num detector do tipo CCD. Esta câmera CCD foi acoplada a um micro computador do tipo PC, via uma interface comercial, e as imagens são disponibilizadas num monitor. Um software dedicado foi desenvolvido e possui as seguintes funções e características: reconhecimento automático e medidas das áreas de ulceração, opcionalmente, medidas interativas de áreas quaisquer, medidas lineares interativas de comprimentos quaisquer e um amplo banco de dados dedicado a este setor da Oftalmologia. Ainda, todos os comandos podem ser realizados através do teclado ou do mouse, particularmente o de capturar imagem também pode ser acionado através de um pedal desenvolvido especialmente para o sistema. O sistema apresentou uma precisão de 5% (o método convencional, para medidas de úlceras perfeitamente elípticas proporcionava uma precisão de no máximo 13%). O protótipo do sistema está em uso no Hospital das Clínicas de Ribeirão Preto (ambulatório de Oftalmologia, setor de Doenças Oculares Externas), tem demonstrado excelente desempenho e estudos clínicos, agora proporcionados pela automação do sistema, começam a ser realizados / A system for diagnostic and follow up of External Ocular Diseases has been developed, particularly for Corneal Ulcers, and has been implemented in a Hospital-School for daily use. The corneal ulcers, until then, have been evaluated in a subjective and qualitative way, just by estimating the affected area. Its clinical evolution is indicated by the increasing/decreasing of the affected area. In order to evaluate quantitatively and standardize the evolution of this pathology we have developed the present system. The system consisted in attaching to a Slit Lamp (ocular biomicroscope) a beam splitter in the parallel rays optical path and an optical system, in order to provide simultaneously the ocular images to the Slit Lamp ocular lenses and to a CCD camera. The camera has been attached to a PC, via a commercial frame grabber and the images are displayed in a monitor. A dedicated software has been developed and it has the following functions and features: corneal ulcers self recognizing and area measurements, optional interactive area and extension measurement of any image and a data bank dedicated for this sector of the Ophthalmology. Also all the commands are available for keyboard or mouse clicking. Particularly, the image capturing command can also be turned ON/OFF by clicking a pedal, which was specially developed for the system. The precision of the measurements of the system is 5% (the conventional method, for perfect elliptical ulcer areas provides a maximum precision of 13%). The system\'s prototype is being used in the Hospital das Clínicas de Ribeirão Preto and it has presented excellent performance. Clinical studies are now being able to be done due to the automation of the clinical evaluations
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Optical Coherence Photoacoustic Microscopy (OC-PAM) for Multimodal ImagingLiu, Xiaojing 23 November 2016 (has links)
Optical coherence tomography (OCT) and Photoacoustic microscopy (PAM) are two noninvasive, high-resolution, three-dimensional, biomedical imaging modalities based on different contrast mechanisms. OCT detects the light backscattered from a biological sample either in the time or spectral domain using an interferometer to form an image. PAM is sensitive to optical absorption by detecting the light-induced acoustic waves to form an image. Due to their complementary contrast mechanisms, OCT and PAM are suitable for being combined to achieve multimodal imaging.
In this dissertation, an optical coherence photoacoustic microscopy (OC-PAM) system was developed for in vivo multimodal retinal imaging with a pulsed broadband NIR light source. To test the capabilities of the system on multimodal ophthalmic imaging, the retina of pigmented rats was imaged. The OCT images showed the retinal structures with quality similar to conventional OCT, while the PAM images revealed the distribution of melanin in the retina since the NIR PAM signals are generated mainly from melanin in the posterior segment of the eye.
By using the pulsed broadband light source, the OCT image quality highly depends on the pulse-to-pulse stability of the light source without averaging. In addition, laser safety is always a concern for in vivo applications, especially for eye imaging with a pulsed light source. Therefore, a continuous wave (CW) light source is desired for OC-PAM applications. An OC-PAM system using an intensity-modulated CW superluminescent diode was then developed. The system was tested for multimodal imaging the vasculature of a mouse ear in vivo by using Gold Nanorods (GNRs) as contrast agent for PAM, as well as excised porcine eyes ex vivo.
Since the quantitative information of the optical properties extracted from the proposed NIR OC-PAM system is potentially able to provide a unique technique to evaluate the existence of melanin and lipofuscin specifically, a phantom study has been conducted and the relationship between image intensity of OCT and PAM was interpreted to represent the relationship between the optical scattering property and optical absorption property. It will be strong evidence for practical application of the proposed NIR OC-PAM system.
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Ögonsjuksköterskors upplevelser av att vårda patienter som behandlas med intravitreala injektioner : En intervjustudie / Ophthalmic nurses’ experiences of caring for patients being treated with intravitreal injectionsNydén, Karin, Wirström, Malin January 2022 (has links)
Problemformulering: Behandling med intravitreala injektioner ökar och patienter som genomgår denna behandling upplever ofta oro och osäkerhet. Det finns behov att stärka och tydliggöra ögonsjuksköterskans roll i omvårdnaden runt patienter som får injektionsbehandling. Detta för att på bästa sätt värna om både patienten och den egna professionen. Syfte: Syftet var att belysa ögonsjuksköterskors upplevelser av att vårda patienter som behandlas med intravitreala injektioner. Metod: En intervjustudie med kvalitativ metod med semistrukturerade frågor och induktiv ansats genomfördes. Åtta ögonsjuksköterskor från fem ögonmottagningar i Mellansverige deltog i studien. Resultat: Analysen resulterade i fem kategorier och tio subkategorier. De fem kategorierna var; Ögonsjuksköterskans roll, Meningsfullt arbete, Patientperspektiv - ögonsjuksköterskornas upplevelser, Upplevda utmaningar och Betydelsefull utveckling. Konklusion: Ögonsjuksköterskorna upplevde sitt arbete meningsfullt och positivt, där de såg sig ha en viktig roll för patienterna. Den dagliga omvårdnaden blev dock inte alltid synlig och ögonsjuksköterskorna kunde ibland ha svårt att identifiera omvårdnaden de gav. Genom att utforma en lätthanterlig och tidseffektiv omvårdnadsdokumentation och individuell vårdplan kan ögonsjuksköterskans omvårdnad synliggöras vilket i sin tur kan möjliggöra patienternas delaktighet och stärka patientsäkerheten. Gruppinformation till patienter skulle också kunna vara ett led i utvecklingen. Förslag på vidare forskning är djupintervjuer med patienter och ögonsjuksköterskor för att undersöka hur vården skulle kunna utvecklas. / Problem definition: Treatment with intravitreal injections is increasing and patients undergoing this treatment often experience anxiety and insecurity. There is a need to strengthen and clarify the ophthalmic nurse's role in the care of patients receiving injection treatment. This is to best protect both the patient and the ophthalmic nurse’s profession. Purpose: The purpose was to illustrate the ophthalmic nurses’ experiences of caring for patients being treated with intravitreal injections. Method: A qualitative interview study with semi-structured questions and an inductive approach was performed. Eight ophthalmic nurses from five ophthalmic clinics in Central Sweden participated in the study. Results: The analysis resulted in five categories and ten subcategories. The five categories were; The ophthalmic nurse's role, Meaningful work, Patient perspective - The ophthalmic nurses' experiences, Perceived challenges and Significant development. Conclusion: The ophthalmic nurses experienced their work meaningful and positively, where they saw themselves as having an important role for the patients. However, daily care did not always become visible and the ophthalmic nurses could sometimes find it difficult to identify the care they provided. By designing an easy-to-use and time-efficient nursing documentation and individual care plan, the ophthalmic nurse's nursing can be made visible, which in turn can enable patients' participation and strengthen patient safety. Group information to patients could also be part of the development. Suggestions for further research are in-depth interviews with patients and ophthalmic nurses to investigate how the care could be developed.
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Erfarenheter av sjuksköterskemottagning inom ögonsjukvård : En systematisk litteraturstudie / Experience of nurse-run clinic in ophthalmic care : – a systematic literature reviewBylund, Lina, Stålfors, Sandra January 2022 (has links)
Bakgrund: Behovet av ögonsjukvård ökar, ett sätt att möta det ökande behovet är genom sjuksköterskemottagningar. Uppgiftsväxling till sjuksköterskemottagningar medför förändringar för såväl patienter, sjuksköterskor som hälso- och sjukvårdens organisation. Det är därför betydelsefullt att tillvarata erfarenheter för att säkerställa vård med hög kvalité och främja en god arbetsmiljö. Syfte: Syftet var att belysa erfarenheter av sjuksköterskemottagning inom ögonsjukvård. Metod: En systematisk litteraturstudie med kvalitativ design och induktiv ansats. Resultat: Kategorierna som framkom var: nya arbetsuppgifter, säker vård, effektiv resursanvändning och vårdrelation. Med rätt förutsättningar kunde uppgiftsväxling genomföras på ett säkert sätt inom ögonsjukvård, därmed ökades mottagningarnas kapacitet. De nya arbetsuppgifterna föregicks av utbildning och upplevdes utveckla yrkesrollen. Förbättrad tillgänglighet och mer tid under besöken upplevdes som positivt av patienterna och stärkte vårdrelationen med sjuksköterskorna. Både patienter och sjuksköterskors erfarenheter av sjuksköterskemottagningar var positiva. Slutsats: Uppgiftsväxling till sjuksköterskemottagning kan stärka yrkesrollen, genomföras på ett säkert sätt, öka kapaciteten och stärka vårdrelationen. När sjuksköterskemottagningar utvecklas behöver förutsättningar skapas för en god arbetsmiljö och säker vård. Mer forskning behövs om hur arbetsmiljön och gruppdynamiken inom yrkeskåren och mellan yrkesgrupper påverkas vid uppgiftsväxling. Specialistsjuksköterskeutbildningen med inriktning mot ögonsjukvård behöver förbereda studenterna på en dynamisk yrkesroll. / Background: The need for ophthalmic care is increasing, one way to meet the increasing need is through nurse-run clinics, which entails changes for patients, nurses as well as the health care system. It is important to take advantage of experiences to ensure high-quality care and promote a good working environment Aim: The aim was to highlight experiences of nurse-run clinic in ophthalmology. Method: A systematic literature review with qualitive design and inductive approach. Results: The categories that emerged were: new tasks, safe care, using resources efficiently and care relationship. Both patients and nurses' experiences of nursing clinics were positive. With the right conditions, task-shifting could be carried out safely in ophthalmic care, thereby increasing the capacity of the clinics. The new tasks were preceded by training and were perceived to affect the professional role in a positive way. Improved accessibility and increased time during the visits were perceived as positive by the patients and strengthened the care relationship with the nurses. Conclusion: As nurse-run clinics develop, conditions need to be created for a good working environment and safe care. Task-shifting to nurse-run clinics can strengthen the professional role, be carried out safely, increase capacity and strengthen the care relationship. More research is needed on how the work environment and group dynamics within the profession and between occupational groups are affected when task-shifting is implemented. Specialist nurse education in ophthalmic care need to prepare students for a dynamic professional role.
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Ögonsjuksköterskans uppfattning av telefonrådgivning på ögonmottagning : En fenomenografisk intervjustudieFransson, Theres, Frideryd, Marlene January 2021 (has links)
Bakgrund: Telefonrådgivning har använts som kommunikationssätt sedan 30-talet inom sjukvården. I nutid är telefonrådgivning ett väl etablerat och beprövat kommunikationsalternativ som brukas runt om i Sverige. Dock belyser forskning telefonrådgivning som en komplex arbetsuppgift. Inom oftalmologi finns det vidare sparsam forskning kring just ögonsjuksköterskans uppfattning av telefonrådgivning. Syfte: Syftet var att undersöka ögonsjuksköterskans uppfattning av telefonrådgivning på ögonmottagning. Metod: Metoden som användes var av kvalitativ design med en fenomenografisk ansats. Åtta ögonsjuksköterskor från södra Sverige som arbetade på ögonmottagning intervjuades enskilt. En fenomenografisk analysmetod valdes att användas för analysering av data. Resultat: Analysen resulterade i tre beskrivningskategorier: (1) Relationens betydelse mellan ögonsjuksköterska och patient, (2) Aspekter som begränsar och underlättar bedömningen mellan ögonsjuksköterska och patient samt (3) Betydelsen av kunskap, stöd och erfarenhet för ögonsjuksköterskan. Slutsats: Det framkom olika begränsande och underlättande aspekter som påverkar bedömningen och mötet med patienten. Ögonsjuksköterskan uppfattade relationen med patienten som en central del i arbetet med telefonrådgivning. Likaså uppfattades stöd i olika former samt kunskapsutveckling och erfarenhet kring området som betydelsefullt. Resultatet visar, likt tidigare forskning, att telefonrådgivning är en mycket komplex arbetsuppgift. / Background: Telephone counseling has been used as a means of communication since the 1930s in healthcare. Today, telephone counseling is a well-established and proven communication alternative that is used around Sweden. However, research highlights telephone counseling as a complex task. In ophthalmology, there is also sparse research on the ophthalmic nurse´s perception of telephone counseling. Aim: The purpose was to investigate the ophthalmic nurse conception of telephone counseling at an eye clinic.Method: The method used was of qualitative design with a phenomenographic approach. Eight ophthalmic nurse´s from southern Sweden who worked at the eye clinic were interviewed individually. A phenomenographic analysis method was chosen to be used for data analysis. Results: The analysis resulted in three descriptive categories: (1) The importance of the relationship between the ophthalmic nurse and the patient, (2) Aspects that limit and facilitate the assessment between the ophthalmic nurse and the patient and (3) The importance of knowledge, support and experience for the ophthalmic nurse. Conclusion: Various limiting and facilitating aspects emerged that affect the assessment and the meeting with the patient. The ophthalmic nurse perceived the relationship with the patient as a central part of the work with telephone counseling. Likewise, support in various forms as well as knowledge development and experience in the area were perceived as significant. The results show, like previous research, that telephone counseling is a very complex task.
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Ögonsjuksköterskors erfarenheter av att arbeta på ögonmottagning : en intervjustudieLindren, Marie, Helg, Madelene January 2023 (has links)
Bakgrund: I takt med en växande befolkning samt högre livslängd och därmed en ökning av oftalmologiska sjukdomar behöver ögonsjuksköterskor utveckla sin roll inom ögonsjukvården. Ögonsjuksköterskor innehar en specialistutbildning som tillhandahåller kompetens att självständigt bedöma och behandla vårdtagare med ögonsjukdomar. Syfte: Beskriva ögonsjuksköterskors erfarenheter av att arbeta på ögonmottagning.Metod: En kvalitativ intervjustudie utfördes med tio ögonsjuksköterskor som arbetat på ögonmottagning minst ett år. Resultat: Innehållsanalysen utmynnade i tre kategorier och nio subkategorier. Ögonsjukvården ansågs vara en omfattande specialitet med varierande arbetsuppgifter som undergår kontinuerlig medicinsk och teknisk utveckling. Med det växande behovet av ögonsjukvård som ögonsjuksköterskorna ställdes inför, erfarades en ökad arbetsbörda samt tidspress vilket påverkade vårdtagare och personal negativt. Uppgiftsväxling ansågs som en positiv utveckling för både patienter och ögonsjuksköterskor. Teamarbetet och kollegialt stöd var av betydelse då ögonsjuksköterskorna kände sig mer förtrogna i sina beslutstaganden, vilket bidrog till en mer patientsäker vård. Samtidigt var det positivt med egna mottagningar då den personcentrerade vården och ögonsjuksköterskornas kunskap kom till sin rätt. Slutsats: Trots flera faktorer som gör arbetet på ögonmottagning intressant och utvecklande finns det möjligheter till förbättring. Ögonsjuksköterskors arbetssätt på ögonmottagning bör därför ses över. Ögonsjuksköterskor bör samarbeta ytterligare för att effektivisera och stressreducera för varandra. Likaså bör ögonsjuksköterskor kompetensväxla i större utsträckning för att nyttja sin kompetens ytterligare och kostnadseffektivisera vården. / Background: In line with a growing population and higher life expectancy and thus an increase in ophthalmological diseases ophthalmic nurses need to develop their role in ophthalmology. Ophthalmic nurses hold a specialist education that provides competence to independently assess and treat patients with ophthalmic diseases.Aim: Describe the ophthalmic nurses experiences of working in eye clinics.Method: A qualitative interview method was conducted with ten ophthalmic nurses with work experience of at least one year in an eye clinic. Results: The content analysis resulted in three categories and nine subcategories. Ophthalmology was considered an extensive specialty that undergoes continuous medical and technical development. With a growing need for eye care the ophthalmic nurses were faced with increased workload and time pressure, which negatively affected care recipients and staff. Task-shifting was considered a positive development for care recipients and ophthalmic nurses. Teamwork and peer support were important so the ophthalmic nurses would feel confident in their decision making, which contributed to a more patient-safe care. Nurse-led clinics were also considered positive as the person-centered care and the ophthalmic nurses knowledge came into place.Conclusion: Though several factors make working on an eye clinic interesting and developing, there are improvement opportunities. Ophthalmic nurses working methods should be reviewed. Ophthalmic nurses should collaborate further to improve efficiency and reduce stress for each other. Ophthalmic nurses should be able to task shift to a greater extent to further utilize their competence and make care more cost-efficient.
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Ögonsjuksköterskans erfarenhet av diabetespatienters besök vid ögonbottenfotografering : En kvalitativ intervjustudie / The ophthalmic nurse's experience of diabetes patients' visits for fundus photography : A qualitative interview studyBengtsson, Therese, Petersson, Matilda January 2023 (has links)
Bakgrund: Diabetesretinopati är en av de vanligaste komplikationerna vid diabetes, och idag finns det en nollvision för allvarlig synskada hos diabetespatienter. Det går att upptäcka diabetesretinopati i ett tidigt skede om regelbunden ögonbottenfotografering görs. Forskningen som finns om ögonbottenfotografering utifrån ögonsjuksköterskans perspektiv är sparsam. Syfte: var att belysa ögonsjuksköterskans erfarenhet av diabetespatienters besök vid ögonbottenfotografering. Metod: Metoden som användes var en kvalitativ design med ett induktivt tillvägagångssätt. Åtta semistrukturerade intervjuer genomfördes enskilt med ögonsjuksköterskor. En kvalitativ innehållsanalys beskriven av Lundman och Hällgren Graneheim (2017) användes för att analysera data. Resultat: Ögonsjuksköterskorna angav att tiden inte alltid räckte till, att det kunde vara stressigt, samt att många patienter står i kö för ögonbottenfotografering och kön tar inte slut. Ögonsjuksköterskornas erfarenhet var att många patienter inte har kunskap om varför det är viktigt att komma på ögonbottenfotografering och att en del uteblir. Resultatet visade att ögonsjuksköterskorna hade bra kunskap om att bedöma ögonbottenfotograferingar och att ett flertal gav patienten information av resultatet muntligt vid besöket. Resultatet visade även en del positiva erfarenheter, bland annat fördelar med modern teknik samt fördelar i samverkan med andra professioner. Slutsats: Många diabetespatienter har kunskap om diabetes, däremot är det flertal som har okunskap gällande vikten av att gå på regelbunden ögonbottenfotografering. För att upprätthålla nollvisionen för allvarlig synskada hos diabetespatienter behövs mer information till denna patientgrupp. Ögonsjuksköterskan behöver i sin roll som omvårdnadsspecialist mer tid för informationsgivning i mötet med patienten för att ge patienten kunskap om sjukdomen och hur viktigt det är med ögonbottenfotografering. / Background: Diabetic retinopathy is a common diabetes complication, today there is a zero vision for severe visual impairment in diabetic patients. Diabetic retinopathy can be detected early if regular fundus photography is done. Research on fundus photography from the ophthalmic nurse perspective is sparse. Aim: was to illustrate the ophthalmic nurse's experience of diabetes patients' visits for fundus photography. Method: Qualitative design with inductive approach was used where eight semi-structured interviews were conducted individually with ophthalmic nurses. A qualitative content analysis described by Lundman and Hällgren Graneheim (2017) was used for data analysis. Results: The ophthalmic nurses stated that the time was not always enough, it could be stressful, and many patients are queuing to come for fundus photography. The ophthalmic nurses experience was that many patients don´t have knowledge of why it is important to have fundus photography and that some do not attend. Results showed that the ophthalmic nurses had good knowledge of assessing fundus photography and a majority gave the patient information about results verbally during the visit. Results also showed positive experiences, including advantages of modern technology and advantages in cooperation with other professions. Conclusion: Many diabetic patients are knowledgeable about diabetes, but majority are ignorant of the importance of regular fundus photography. To maintain zero vision for severe visual impairment in diabetic patients, more information is needed for these patients. As a nursing specialist, the ophthalmic nurse needs more time with the patient to provide information about the disease and the importance of fundus photography.
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The Effects of Inhibiting Wnt Secretion and Activity on Cranial And Neural DevelopmentHulet, Julie Louise 01 June 2015 (has links) (PDF)
Wnt signaling has been shown to have several roles in the development of sensory neurons, particularly in the ophthalmic portion of the trigeminal nerve. Many of these studies have relied on the conclusion that Wnt is necessary but not sufficient for the induction and maintenance of the neural precursor cells that develop in the ophthalmic placode. Wnt had been inhibited in the ophthalmic placode using a dominant negative t-cell factor (TCF) and resulted in the loss of Pax3 expression (indicative of undifferentiated placode cells) in all targeted cells, suggesting a loss of specification/commitment of these cells to the sensory neuron fate. This study aimed to build on that conclusion by identifying the source of Wnt signaling that allowed for the maintenance of these placode cells. To investigate this, chick embryo ex ovo cultures were used and treated with small molecule chemical Wnt inhibitors to globally knock out Wnt signaling. The embryos were then sectioned and stained for cell markers of undifferentiated placode and differentiated neural cells (Pax3 and Islet1, respectively). Also used was a conditional knockout of Porcn, a gene critical to post-transcriptional modification of the Wnt ligand, using Wnt1-cre as a driver; this allowed for the knockout of Wnt secretion from the dorsal neural tube as well as neural crest cells. The data showed a decrease in placode cell differentiation but did not indicate a necessity for Wnt in maintenance of the ophthalmic placode cells—there was no loss of Pax3 expressing cells in the ectoderm. This suggested that maintenance of the ophthalmic placode could be through alternate pathways. Data is also presented describing how loss of Porcn in Wnt1 expressing cells impacts craniofacial development, where the mouse mutant used in this study displayed the absence and underdevelopment of cranial neural crest structures.
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The Role of Pax3 in Neuronal Differentiation of the Ophthalmic (OpV) Trigeminal Placode and Neural Tube during Chicken Embryonic DevelopmentBradshaw, James R. 16 March 2006 (has links) (PDF)
Pax3 has been used as a valuable marker in research aimed at understanding tissue interactions involved in trigeminal ophthalmic (opV) placode development. While Pax3 expression coincides with opV neuron specification, the function of Pax3 in these cells has not previously been investigated. Splotch mutant mice (which lack Pax3) have a reduced trigeminal ganglion; however it is not clear whether this reduction is due to neural crest or placode cells. We have used electroporation in the chick model system to block or ectopically express Pax3 at key times in opV placode development. Using several markers of placode cell differentiation, we have determined the experimental effects manipulating Pax3. Blocking placodal Pax3 with gene specific morpholinos resulted in a loss of migratory placode cells, and a downregulation of all opV placode markers in targeted cells. Ectopic expression of Pax3, either within the placode domain or in adjacent cranial ectoderm, resulted in the upregulation of some but not all placode markers. We conclude that opV placodal Pax3 expression is required for normal placode cell development, and hypothesize that its expression must be tightly regulated in order for placode cells to fully differentiate. The precise role of Pax3 and Pax7 in the restriction and differentiation of dorsal interneuron progenitors has been difficult to assess due to the many additional factors involved in specification and patterning of the neural tube. We have used electroporation in the chick model system to ectopically express Pax3 and Pax7 unilaterally in the neural tube. Using several markers for differentiation of ventral and dorsal neuronal progenitors, we have experimentally determined the effects of Pax3 and Pax7 ventrally and dorsally. Ectopic expression of these transcription factors in the ventral neural tube resulted in the loss of motorneurons. Though mis-expression did not qualitatively affect commissural neurons as assayed by neurofilament staining, ectopic expression of Pax3 and Pax7 in the dorsal neural tube stopped dorsal interneuron progenitors from differentiating. We conclude that Pax3 and Pax7 expression is sufficient to restrict ventral neuron identity. We also hypothesize that downregulation of these transcription factors in the dorsal neural tube is required for normal dorsal interneuron differentiation.
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A Model for Sensory Neuron Development by FGF and Notch: A Multifactorial ApproachVoelkel, Jacob Eugene 28 June 2013 (has links) (PDF)
The ophthalmic trigeminal placode (opV) exclusively gives rise to sensory neurons. A number of signaling pathways including Wnt, PDGF, FGF, and Notch are all involved in the progression of an undifferentiated cell in the opV placode to a proneural cell in the condensing opV ganglion. However, the regulatory relationships between these signal transduction pathways are still unknown. To determine if FGF activation acts to modulate Notch signaling in the sensory neurogenesis pathway, a novel multifactorial approach was employed: FGF signaling was inhibited in individual cells and globally with simultaneous inactivation of Notch signaling in chick embryos to investigate if FGF activation downregulates Notch thereby driving neurogenesis. These experiments resulted in few differentiating opV cells in the mesenchymal region of future ganglion formation suggesting an alternate regulatory relationship between FGF and Notch where either reduced Notch activity allows for FGFR4 expression (leading to FGF signaling and neurogenesis), or a parallel relationship where FGF and Notch act independently of one another to induce neurogenesis. To distinguish between these two possibilities Notch signaling was inhibited with DAPT, a gamma-secretase inhibitor, and assayed for FGFR4 mRNA expression. These results indicated FGFR4 is not upregulated by reduced Notch activity, suggesting that FGF and Notch act in parallel to promote neurogenesis. During these experiments it was observed that Notch inhibition resulted in an undefined ectoderm in the opV placode region. To investigate this, FGF and Notch were inhibited by SU5402, an FGF antagonist, and DAPT, and later sectioned and stained for Laminin. In DAPT treated embryos the basement membrane became highly fragmented, a remarkable observation not yet reported. From these data a proposed mechanism was established where activation of FGF with parallel downregulation of Notch leads to disruption of extracellular matrix proteins in the basement membrane resulting in fragmentation and subsequent delamination of differentiating opV placode cells.
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