The primary purpose of this research was to examine the effects of HRT in women with acute estrogen deficiency from surgically induced menopause. The secondary purpose was to evaluate how HRT improves symptoms of acute estrogen deficiency and quality of life (QOL) in women using hormone supplementation. Peer reviewed articles published from 2000 to 2017 that were written in the English language with a focus on the use of HRT in women with acute estrogen deficiency after surgical menopause were evaluated for relevance. Evidence suggests the primary reason for decreased use of HRT is the associated risks outweighing the benefits; however, this is not reflected in health care provider's (HCP's) clinical experience. HCP's were more likely to prescribe HRT for themselves or family members if they were experiencing the negative side effects of estrogen deficiency due to surgical menopause, but not to women in their care with similar clinical manifestations of menopause. Additionally, serious risks associated with HRT for acute estrogen deficiency remain incongruent with HRT for women experiencing natural menopause; although risk for breast cancer due to HRT was a universal concern. Risks of HRT related to thromboembolism, stroke and heart disease, were discussed with comparison to the undesirable clinical manifestations of menopause. Results indicate further education and research is needed that explores the risks and benefits for HRT in women with sudden onset of estrogen deficiency from surgical menopause.

Feminist philosophy of science has long been considered a fringe element of philosophy of science as a whole. A careful consideration of the treatment of the key concept of objectivity by such philosophical heavyweights as Thomas Kuhn and Karl Popper, followed by an analysis of the concept of objectivity with the work of such feminist philosophers of science as Donna Haraway, Lynn Hankinson Nelson, and Sandra Harding, reveals that feminist philosophers of science are not members of some fringe movement of philosophy of science, but rather are doing philosophical work which is both crucial and connected to the work of other, "mainstream" philosophers of science. / Master of Arts

Thesis (PhD)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Diabetes mellitus is amongst the leading causes of morbidity and mortality in the world, affecting young, adult and old people. Beta cell replacement therapy for insulin delivery remains the ultimate remedy for diabetes. However, insufficient donor pancreas and the use of immunosuppressive drugs prevent the wide-spread of this therapy. Other avenues of self generated beta cells within the organ itself need to be explored. Therefore, understanding the chronobiology of cellular mechanisms in the lineage of beta cell induced neogenesis is a valuable tool in improving beta cell replacement in patients with diabetes. The aim of this study was to induce recapitulation of the morpho-genetic sequence of endocrine cells development in the pancreas of rats after the pancreatic duct ligation (PDL) procedure. Serial sections of PDL tissues of the pancreas were obtained from 78 Sprague- Dawley rats and were assessed morphologically. The immunofluorescent tissues were statistically analysed using a computerized morphometry technique. The protein expression indices of Caspase3, Insulin, Pdx1, Ngn3, NeuroD and Pax6 were quantified. The efficiency levels of coexpression of these homeodomain proteins separately with insulin were defined by the ratio of the mean value of insulin expression to the mean value of their respective protein expression. The morphological changes were characterized by the appearance of granulated acinar cells at 6 hours post-PDL and the proliferation of endocrine tissues from 84 hours through to 120 hours. The morpho-immunofluorescent evaluation showed the highest immunoreactivity of Caspase3 and Pdx1 at 6 hours, Ngn3 at 36 hours, Pax6 and insulin at 84 hours while NeuroD expression was at 120 hours. The immunohistofluorescent analysis showed that caspase3 and Pdx1 were the first to be expressed at 6 hours while the insulin and NeuroD expression appeared later at 84 hours and 120 hours, respectively. However, Pax6 expression was continuous across time periods post-PDL, while Ngn3 expression showed a peak at 36 hours. The efficiency (highest and earliest expression) of co-expression of all these homeodomain proteins with insulin was restricted between 12 hours and 24 hours. The optimal efficiency was at 12 hours by Ngn3 with insulin. A good efficiency was shown for Pdx1 with insulin, NeuroD with insulin and Pax6 with insulin at 12 hours and 24 hours, respectively. A low efficiency was observed for insulin and caspase3 co-expression at 24 hours. This study suggests that for transplantation, PDL tissues harvested at an early time post-PDL (between 12 and 24 hours) could yield a higher success rate; the study also provides evidence for a connection between morphological changes in the PDL pancreas and the protein synthesis necessary for the lineage of endocrine cell development. / AFRIKAANSE OPSOMMING: Diabetes Mellitus resorteer onder die vernaamste oorsake van morbiditeit en mortaliteit wêreldwyd, en tuister jongmense, volwassenes en bejaardes. Daar bestaan egter ‘n wêreldwye tekort aan skenkerorgane met immuun-onderdrukingsterapie as ondersteuningsbehandeling. Beta-sel vervangingsterapie, vir die voorsiening van insulien, bly daarom die voorkeur behandeling vir die siekte wat noodsaak dat die wetenskap kyk na alternatiewe behandelingsregimens wat meganismes rondom orgaanregenerasie insluit. Begrip van die chronobiologie van die sellulêre meganismes betrokke rondom beta-sel ontwikkeling mag waardevolle lig werp op die neogenese van beta-selle wat gevolglik daartoe mag lei dat beta-sel vervanging as ‘n moontlike behandelingsterapie oorweeg mag word vir pasiënte met suikersiekte. Die oogmerk van hierdie studie is om die rekapitulasie van die morfo-genetiese volgorde van die endokriene pankreas na afbinding van die pankreasbuis te bepaal. Pankreasbuis afbinding is op 78 Sprague-Dawley laboratorium rotte onder algemene narkose uitgevoer, die pankreas is na voorafbepaalde tydsvakke verwyder en in histologiese seriesnitte gesny. Snitte is immunositochemiese gekleur en morfometries assesseer. Die afskeidingsindeks vir selboodskappers vir Caspase3, Insulien, Pdx1, Ngn3, NeuroD en Pax6 is kwantifiseer. Die gelyktydige afskeiding van elk van bogenoemde boodskappers tesame met insulien is omskryf as ‘n verhouding tot mekaar en in terme van dié van insulien. Die morfologiese verandering in die weefsel bespeur is gekenmerk deur die verskyn van gegranuleerde asinêre selle ses (6) ure na buisafbinding en die proliferasie van endokriene weefsel vanaf vier-en-tagtig (84) ure deurlopend tot een-honderd-en-twintig (120) ure. Die morfo-immunofluoresserende evaluering toon dat Caspase3 en Pdx1 by 6 uur die hoogste is, die van Ngn3 by 36 ure, Pax6 en insulien by 84 ure en NeuroD by 120 ure. Verder toon die analise dat Caspase3 en Pdx1 rondom 6 ure hul verskyning gemaak het terwyl dié van insulien en NeuroD eers rondom 84 tot 120 uur verskyn het. Die verskyning van Pax6 het deurlopend regoor al die tydsduurtes verskyn en Ngn3 het rondom 36 uur sy hoogste vlak bereik. Die gelyktydige uitdrukking van homeodomein proteïene tesame met insulien het slegs tussen die tydperke van 12 en 24 ure plaasgevind. Die uitdrukking van Pdx1 met insulien, NeuroD met insulien en Pax6 met insulien het almal tussen 12 en 24 ure plaasgevind. Caspase3 tesame met insulien is slegs by die 24 uur tydsperiode bespeur. Vir die oorplant van pankreas weefsel wat aan buisafbinding onderwerp is suggereer hierdie studie dat die geskikste tyd vir die oes van endokriene weefsel liewer vroeër (12 to 24 ure) as later uitgevoer behoort te word. Verder wil dit voorkom of hierdie tydsperiode ook die hoogste seltelling lewer. Die studie lewer waardevolle inligting oor die verwantskap tussen die morfologiese veranderings wat na buisafbinding plaasvind en die proteïen sintese wat sel-opvolgontwikkeling bevorder.

Mucopolysaccharidosis IIIB (MPS IIIB) is a rare, metabolic disorder that results from a deficiency in the lysosomal hydrolase, α-N-acetylglucosaminidase (Naglu). Naglu is a housekeeping enzyme involved in the degradation pathway of heparan sulfate. A deficiency in active Naglu leads to an accumulation of heparan sulfate within the lysosome, initiating a pathological cascade within the cell. Patients with MPS IIIB experience progressive central nervous system degeneration and die within the first few decades of life. Presently, enzyme replacement therapy, which is a standard of care for other lysosomal storage disorders, is an ineffective treatment for MPS IIIB. This is due to impermeability of the blood-brain barrier (BBB) to exogenous recombinant enzymes. A promising approach to this therapeutic obstacle is protein transduction domains. Protein transduction domains have been shown to facilitate the delivery of active enzyme across the BBB in mice. Previously, our laboratory used Spodoptera frugiperda (Sf9) insect cell system to express human recombinant Naglu fused to a synthetic protein transduction domain (PTD4). The purpose was to use PTD4 to the facilitate the delivery of Naglu across biological membranes, including the blood-brain barrier. However, a missing stop codon following PTD4 limited its transducibility. The stop codon was re-introduced and the improved fusion enzyme, Naglu-PTD4X, was stably expressed in Sf9 cells. The overarching goal of this project is to create a large-scale production of human recombinant Naglu that has the potential to be used to treat the neuropathology of patients with MPS IIIB. This project used a three-step purification system to purify Naglu-PTD4X. Uptake of Naglu-PTD4X was assessed in MPS IIIB fibroblasts using a fluorogenic activity assay, immunoblotting, and immunocytochemistry. Our purification system was successful at purifying Naglu-PTD4X to homogeneity with a 26% yield and specific activity of 84,000 units/mg. An increase in Naglu activity was detected in MPS IIIB fibroblasts following incubation with Naglu-PTD4X. Future directions will focus on optimizing immunodetection and conducting BBB penetration studies in murine models. / Graduate / 2020-06-21

As doenças raras são epidemiologicamente caracterizadas por ocorrerem entre 0,65-1:1.000 indivíduos. Houve importante incremento no surgimento de tratamentos específicos para muitas destas condições a partir da publicação de legislações específicas em diferentes países (sendo o pioneiro em 1983 nos EUA o chamado 'Orphan Drug Act'). Dentre as doenças que dispõem atualmente de tratamento específico está a Doença de Fabry, uma doença genética classificada erro inato do metabolismo do grupo das doenças Lísossômica se caracterizada pelo acúmulo de glicoesfíngol ipídíos no endotélio vascular, o que ocasiona problemas renais, cardíovasculares e neurológicos. Os problemas renais e cardíovasculares são os responsáveis pela maior morbi-mortalídade entre os portadores da doença. Esta ocorre em homens e mulheres, com manifestações heterogêneas entre indivíduos e diferentes gêneros. O tratamento específ ico da doença é através da chamada Terapia de Reposição Enzimática (TRE) havendo duas opções existentes: a agalsidase alfa e a agalsidase beta. Não há, porém, consenso sobre os resultados da TRE sobre desfechos clínicos relevantes. O alto custo associado a esta terapêutica (cerca de 200 mil dólares/ano/por paciente adulto) é o dificulta o acesso dos pacientes à mesma. Uma das formas se racionalizar a incorporação de tecnologias novas na área de saúde, que se caracteriza empreender uma avaliação objetiva de benefícios e custos associados é a chamada Avaliação de Tecnologias de Saúde. Este conjunto de métodos é cada vez mais empregado para auxiliar ou nortear decisões na área de saúde. Existem, no entanto , dificuldades associadas ao seu emprego no campo das doenças raras. Nossa proposta consiste em tendo como modelo a Doença de Fabry, obter um panorama da situação no Brasil a o acesso a tratamentos de alto custo para doenças raras, e, analisar a aplicabilidade dos princípios da avaliação de tecnologias de saúde no campo das doenças raras, tentando por fim colaborar no aprimoramento do processo de acessibilidade a estes tratamentos. OBJETIVOS Objetivo geral : Avaliar o acesso no Brasil a tratamentos de doenças raras e a aplicabilidade da avaliação de tecnolog ias em saúde no contexto específico destas. Objetivos específicos: 1) Caracterizar as políticas existentes no Brasil em relação ao acesso de medicamentos para doenças raras e avaliar as formas empregadas para este acesso. 2) Colaborar no aprimoramento do processo de incorporação destes tratamentos (de al to custo) no segmento das doenças raras, através da aplicação de principias de 'aval iação de tecnologias em saúde', usando como exemplo a Doença de Fabry. 3) Identificar e propor possíveis estratégias que possam colaborar para uma acessibilidade adequada e justa a tratamentos cl inicamente efetivos no campo das doenças raras. MÉTODOS 1) Foi realizada uma revisão da literatura caracterizando as politicas brasileiras na área de medicamentos e aval iando as formas de acesso utilizadas pelos pacientes; 2) Uma segunda revisão, de caráter sistemático, sobre os efeitos da TRE na DF, foca d a nos efe itos sobre a nefropatia e a cardiopatia (sistemas cujo comprometimento em pacientes com DF causa maior morbi-mortalidade) da doença foi feita. Baseado nos dados obtidos elaborou-se um modelo probabilístico (markoviano) para avaliar o efeito da TRE sobre a nefropatia da DF seguido de aval iação do custo-efetividade. A partir de uma análise destes resultados e da li teratura, foram identificados os aspectos que mais influenciariam a acessibilidade ao tratamento, seguida da elaboração de propostas para auxiliar a incorporação e a acessibil idade a estes tratamentos. RESULTADOS 1) A política de assistência farmacêutica brasileira atual é baseada em elencos de medicamentos divididos em atenção básica e do 'componente especiali zado'. Não existe uma política especifica direcionada aos tratamentos (de alto custo) dos portadores de doenças raras. 2) A revisão empreendida mostrou que dentre os dois sistemas aval iados de forma particular (pela morbi-mortalidade associada) havia mais dados quer sobre história natural , quer sobre efeitos da TRE em relação à nefropatia, tendo sido esta escolh ida então como foco da modelagem . O modelo construido foi capaz de identificar um subgrupo de pacientes com DF que quando tratado com TRE tem redução significativa (diferença absoluta de 10%) na probabilidade de ter progressão da nefropatia (evoluir a estágio dialítico). A despeito dos benefícios observados a análise mostrou ser esta opção não custo-efetiva no contexto existente (custo é superior ao limite preconizado pela OMS de s 3 vezes o PIB per capíta do Brasil). 3) A acessibilidade é ainda um obstáculo ao uso destes medicamentos. O custo é o limitante central da acessibilidade aos tratamentos específicos destas patologias. Atuar em aspectos associados a este e às pol íticas vigentes seriam formas de tentar mudar este cenário. CONCLUSÕES 1) Não há em nosso país políticas que sistematizem o processo de incorporação de tratamentos (de alto custo) para doenças raras. O acesso a estes é disperso, no caso da DF não existe disponibil idade da terapia de reposição enzimática via SUS. 2) A revisão sobre o efeito da TRE na nefropatia mostrou resultados muito heterogêneos. Foi possivel, no entanto, elaborar um modelo avaliando TRE na nefropatia da DM, o qual é o primeiro conhecido utilizando este desfecho especifico e elaborado dentro contexto brasileiro. A despeito de identificado um subgrupo de pacientes que poderia beneficiar-se significativamente com o tratamento especifico a estratégia não foi custo-efetiva para este desfecho. Os custos associados foram o limitante central. Novas opções em termos de efetivação da incorporação destas tecnologias devem ser consideradas. / BACKGROUND. According to the WHO definition rare diseases occur between 0.65-1/1,000 individuals. The U.S. 'Orphan Drug Act' in 1983', the first legislation with incentives for the development of therapies for rare diseases had an impact on the development of treatments for these diseases. Fabry Disease (FD) is a rare genetic disease characterized by accumulation of glycosphingolipids in vascular endothelium leading to systemic dysfunction (renal, cardiovascular, and neurologic disease). This disease has specific treatment available, with two options of recombinant enzymes (alfa or betagalsidase) for enzyme replacement therapy (ERT). There are few controlled trials evaluating their effects, indicating some improvements in neuropathic pain, in heart abnormalities and in globotriaosylceramide (GL-3) levels. Nevertheless most of the clinical benefits of ERT are still unclear. Another aspect is the high cost associated with this treatment which makes it not easily accessible. OBJECTIVES: General Objective: Evaluate access to rare disease treatments in Brazil and the applicability of health technology assessment (HTA) in the context of these diseases. Specific objectives: 1) Evaluate the Brazilian governmental policies for rare diseases treatment and how the access to the treatments is actually done. 2) Evaluate the applicability of health technology assessment (HTA) in the context of rare diseases, using the example of Fabry disease. 3) Identify and propose strategies that could contribute to a fair access to clinically effective treatments for of rare diseases. METHODS: An extensive literature review about the Brazilian policies in the area was performed. In the sequence a systematic review about the subject ERT and FD was conducted. After this, a model estimating the likelihood of nephropathy progression with or without ERT was built, followed by a cost-effectiveness analysis. Another literature review focused in the identification of obstacles to accessibility and possible strategies to overcome them was conducted. RESULTS: 1) There is no specific policy in Brazil regarding high cost drugs for the treatment of rare diseases. 2) ERT appears to slow the progression of nephropathy in the Fonly proteinuria subgroup '. However the cost associated is very high making this option not cost-effective. 3) The accessibility to innovative treatments for rare diseases is not adequate and the high cost of these therapies is a major obstacle to change this scenario. CONCLUSION: There are no policies in Brazil to systematize the access to the specific (high cost) treatments for rare diseases. The model evaluating TRE in FD nephropathy was able to identify benefits for a subgroup of patients. It was the first known model using this specific outcome and built focusing the Brazilian context. However the ERT strategy was not cost-effective for this outcome. The costs associated with these therapies are very high and an important limiting factor to the access. the central. New options should be considered to offer adequate access to the (effective) therapies.

(v AJ) For my diploma thesis I chose Nursing care for patients with complicated peritonitis as a topic, because care for these patients must be complex and often requires long-term stay at the anesthesiology and resuscitation department. These patients require organ support, undergo repeated surgical revisions, and ultimately, if they overcome this critical period, they learn very often self- care, walking, and sometimes adapt to permanent changes in health. It is a disease where there are often sudden changes in the patient's condition. In the theoretical part I tried to describe the disease leading to the development of peritonitis and complications in the form of septic shock and multiorgan failure. In the National Medical Library, I have searched for a comprehensive review of literature since 2005. I searched for keywords and phrases: Peritonitis, Nursing Care, Sepsis, Multiorgan Failure, Circulatory Support, Artificial Pulmonary Ventilation, Continuous Function Replacement kidney care, laparotomy care, drainage care, intra-abdominal hypertension. I obtained other documents using the central search engine UKAŽ, I drew from licensed databases: Bibliographia medica Čechoslovaca, Ebsco, Medline, Pubmed. For the processing of nursing procedures I used the recommendations of professional societies:...

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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.