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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.
11

Oct-4 expression in equine embryonic cells

Harding, Heather Darby 25 April 2007 (has links)
The Oct-4 transcription factor is believed to co-regulate early embryonic development of mammals due to the correlation of its presence with the maintenance of pluripotency. It is commonly used as a marker for the identification of embryonic stem (ES) cells for this reason. Until 1999, Oct-4 studies were limited to in vivo-produced embryos; equine embryos have not been studied for their Oct-4 expression patterns. In addition, equine stem-like cells (defined by marker expression, induced differentiation, passage survival, and morphology) have recently been isolated from in vivo-produced embryos, but no work has been performed in horses to isolate ES cells from in vitroproduced embryos. This study investigated the expression of Oct-4 transcription factor using immunocytochemistry in 42 in vitro-produced embryos aged 1-10 days and in 5 in vivoproduced blastocysts aged 7-10 days. Effective conditions for rapid establishment of a feeder layer of equine fetal fibroblasts were established, and this feeder layer was used to grow isolated equine inner cell mass (ICM) cells from in vitro-produced embryos. The expression of Oct-4 was examined in resultant cell growths. In vitro-produced embryos less than 6 days of age showed variable staining within blastomeres of the same embryo, and the peak of variability correlated with maternal-zygotic transition. After Oct-4 staining of in vitro-produced blastocysts, no cells could be identified as an ICM based on a difference in fluorescent intensity from the other cells of the blasyocysts. However, in vitro-produced blastocysts that were subsequently cultured in vivo contained a presumptive ICM, visible based on greater fluorescent intensity of Oct-4 stain. The trophoblast of all blastocysts also stained positively for Oct-4 protein. Fibroblasts were successfully isolated from equine feti. Treatment with 20 µg/ml of Mitomycin C arrested cell growth without causing excessive death. Fibroblasts were inactivated and frozen, then thawed as needed to establish a confluent monolayer for ICM isolation overnight. ICMs from in vitro-produced embryos formed outgrowths, but none that could be identified morphologically as ES cells. Outgrowth cells contained about 20% Oct-4 expressing cells in sporadic groupings. Assuming appropriate binding of the Oct-4 antibody, Oct-4 expressing cells (potentially indicating pluripotency) are found throughout the embryo in early development and in the feeder layer after co-culture.
12

Synnervens storlek hos myoper och emmetroper med Optical Coherence Tomography

Borgqvist, Elin January 2015 (has links)
Syfte: Syftet med studien var att kontrollera om det finns någon skillnad på synnervens storlek hos myoper och emmetroper med hjälp av optical coherence tomography (OCT).Metod: Totalt deltog 35 personer i studien, 15st emmetroper och 20st myoper. Kriterierna för att man skulle få delta var åldern 18-45 år. Deltagarna delades sedan in i två grupper efter refraktionen, emmetroper mellan +0,75D till -0,25D och myoper minst -0,50D eller högre efter refraktionen. Alla deltagare kontrollerades med biomikroskop för att utesluta förändringar i ögat. OCT kamera användes för att få alla mätvärden i höger öga. Åtta olika mätvärden användes för varje deltagare. Det var disk, cup och bräm area, cup/disk kvot både horisontellt och vertikalt, area kvot, medel cup exkavation och max cup exkavation.Resultat: Mätvärdena sammanställdes i Excel för att analyseras och jämföras med hjälp av ett oberoende T-test. Medelvärden och standardavvikelser (SD) räknades också de ut i Excel. Det fanns ingen signifikant skillnad mellan grupperna, p >0,05. En regressionsanalys gjordes för att jämföra korrelationen mellan den sfäriska ekvivalenten hos myoperna med disk arean. Korrelationen var väldigt låg (r = 0,01).Slutsats: Denna studie visar att det inte finns någon signifikant skillnad på synnervens storlek hos myoper och emmetroper.
13

Inter-device reliability of swept source and spectral domain optical coherence tomography and retinal layer differences in schizophrenia

Gandu, Swetha 17 November 2021 (has links)
INTRODUCTION: Optical coherence tomography (OCT) is used to study retinal structure in schizophrenia. Changes in retinal structure, especially the retinal nerve fiber layer (RNFL) have been correlated with psychotic disorders. Along with a decrease in macular outer nuclear layer (ONL) thickness and an increase in macular outer plexiform layer (OPL). However, measurement variability is a concern for inner retinal layers since there are various generations of OCT devices resulting in differing measurements. We investigated the inter- and intra-device agreement of macular thickness between spectral domain (SD-OCT) and swept source-OCT (SS-OCT), and compared macula and peripapillary group differences in schizophrenia using SS-OCT for inner retinal layers. Additionally, we expanded on our previous work and investigated whether baseline outer retinal layer data for macular ONL and OPL thickness predicted clinical and cognitive changes in individuals with schizophrenia. METHODS: For the inter- and intra-scanner study, macular OCT thickness was obtained for schizophrenia (SZ, n=30) and healthy controls (HC, n= 22) subjects using SD-OCT (Heidelberg Spectralis) and SS-OCT (DRI Topcon Triton). Peripapillary thickness was obtained using SS-OCT. RNFL, ganglion cell-inner plexiform complex (GCL+), RNFL+ GCL+ (GCL++), and macular thickness were collected. For the longitudinal study, 7 participants diagnosed with either schizophrenia or schizoaffective baseline OCT measurements and clinical measures were obtained for all 7 participants from study 1, along with 6 months follow up clinical measures. OCT measurements for the macular OPL and ONL were gathered using the Heidelberg Spectralis Clinical and cognitive data was gathered. All statistical analyses were performed using R software. RESULTS: There was excellent inter-scanner agreement for GCL+ and GCL++ with Interclass correlation coefficient (ICC) values between r =0.92-0.99. Good to excellent intra-scanner agreement was present except for macular RNFL in the SS-OCT device. No significant peripapillary group differences were identified. Poorer (Global Assessment of Functioning) GAF scores were correlated with thinner macular layers. Greater mania symptoms were associated with smaller peripapillary GCL+ thickness (r=-0.43, p=0.03). Poor overall cognition was associated with smaller peripapillary retinal thickness (r=0.36, p=0.02). For the longitudinal study, an increase in baseline OPL thickness was correlated with worse positive symptoms according to the Positive and Negative Symptom Severity(PANSS) at the 6 month follow up (r=0.77, p=0.04) with a trend level effect for PANSS total scores (r=0.71, p=0.08). There was no significant correlation between the change in clinical or cognitive outcomes for 6 months and baseline OPL and ONL thickness. CONCLUSION: While there is RNFL variability, GCL+ and GCL++ are comparable between scanners SD-OCT and SS-OCT. Given that RNFL thinning is strongly implicated in psychotic disorders, the use of OCT scanners should not be interchanged due to increased RNFL measurement variability. Additionally, though further research is needed on investigating changes in clinical outcomes with changes in OCT measurements, OPL thickness might be a predictor of long-term clinical outcomes or changes in brain pathology for individuals with schizophrenia.
14

Potential vorticity in extratropical cyclones

Berrisford, Paul January 1988 (has links)
No description available.
15

Interaktion der Triphenylmethanfarbstoffe Gentianaviolett und Brillantgrün mit organischen Kationentransportern / Interaction of the triphenylmethane dyes gentian violet and brilliant green with organic cation tranporters

Zapf, Florian Hellmut January 2008 (has links) (PDF)
Polyspezifische organische Kationentransporter (OCTs) der SLC22 Familie transportieren organische Kationen entlang eines elektrochemischen Gradienten und spielen eine entscheidende Rolle bei der Ausscheidung und Gewebeverteilung von endogenen organischen Kationen und bei der Aufnahme, Ausscheidung und Verteilung von kationischen Medikamenten und Toxinen. Zu den endogenen transportierten Substanzen gehört auch der Neurotransmitter Acetylcholin (ACh), der unter anderem in der menschlichen Haut eine wichtige Rolle in der Zelldifferenzierung und –proliferation spielt. Die dermatologischen Antiinfektiva Gentianaviolett (GV) und Brillantgrün (BG) aus der Gruppe der Triphenylmethanfarbstoffe werden in der Behandlung lokaler Wundinfektionen verwendet und zeigen im klinischen Gebrauch Nebenwirkungen wie Wundheilungsstörungen. Es konnte gezeigt werden, dass die Farbstoffe die OCTs konzentrationsabhängig hemmen und es wurden die Werte der halbmaximalen Hemmkonzentration ermittelt. Dabei zeigte sich, dass GV und BG zu den Hemmstoffen mit der höchsten Affinität zu den OCTs gehören. Ein Transport der Farbstoffe durch die OCTs konnte nicht nachgewiesen werden, die toxische Wirkung auf Keratinozyten in in-vitro Versuchen mit menschlichen Zellreihen wurde bestätigt. Ein Zusammenhang zwischen den beobachteten Wundheilungsstörungen unter der Therapie mit Triphenylmethanfarbstoffen und der Hemmung des ACh-Transportes durch die OCTs konnte nicht bestätigt werden. / Polyspecific organic cation transporters (OCTs) of the SLC22 family mediate downhill transport of organic cations and play an essential role in excretion and distribution of endogenous organic cations and for the uptake, elimination and distribution of cationic drugs and toxins. One of these endogenous transported substances is the neurotransmitter Acetylcholin (ACh), which plays an important role in the differentiation and proliferation of human skin cells. The triphenylmethane dyes gentian violet (GV) and brilliant green (BG), that are used in dermatology for the local treatment of infected wounds show side effects such as disruption of the healing of wounds. It could be shown, that the dyes inhibit the OCTs in a concentration-dependent manner and the IC50-values could be determined. The transport of the dyes through the OCTs could not be shown however the toxicity on human keratinocytes could be confirmed in in-vitro essays with human cell lines. A connection between the disruption of wound-healing under therapy with triphenylmethane dyes and the inhibition of the ACh-transport mediated by the OCTs could not be confirmed.
16

Die Aminosäuren W355 und A359 des rOCT1 zeigen substratabhängige Mutationseffekte und ändern nach Mutation die Affinität des Transporters zu TBuA / The amino acids W355 and A359 of rOCT1 show substrate-dependent mutation effects and change the affinity of the transporter to TBuA

Aichner, Christian January 2014 (has links) (PDF)
Die Aminosäuren W355 und A359 des rOCT1 zeigen substratabhängige Mutationseffekte und ändern nach Mutation die Affinität des Transporters zu TBuA / The amino acids W355 and A359 of rOCT1 show substrate-dependent mutation effects and change the affinity of the transporter to TBuA
17

Novel Regulatory Mechanisms Underlying the Expression of the Carbohydrate Response Element Binding Protein (ChREBP): the Roles of Insulin and the POU Protein Oct-1

Sirek, Adam 15 February 2010 (has links)
ChREBP has emerged as one of the key controllers of hepatic lipogenesis. While the function of ChREBP has been extensively investigated, mechanisms underlying its transcriptional regulation remain largely unknown. We located a conserved POU-binding site within mammalian ChREBP promoters, and demonstrated that the POU homeodomain protein Oct-1 binds to this site in the human HepG2 cell line. Oct-1 transfection significantly repressed ChREBP promoter activity 50-75%. Conversely, knockdown of Oct-1 expression with shRNA significantly increased ChREBP expression levels. Furthermore, insulin treatment resulted in a two-fold activation of ChREBP promoter activity, and stimulated endogenous ChREBP expression. We found that the stimulatory effect of insulin on the ChREBP promoter is at least partially dependent on the presence of the POU-binding site, and that insulin treatment reduced Oct-1 expression. Our observations identify Oct-1 as a transcriptional repressor of ChREBP, and suggest that insulin stimulates ChREBP expression via attenuating the repressive effect of Oct-1.
18

Novel Regulatory Mechanisms Underlying the Expression of the Carbohydrate Response Element Binding Protein (ChREBP): the Roles of Insulin and the POU Protein Oct-1

Sirek, Adam 15 February 2010 (has links)
ChREBP has emerged as one of the key controllers of hepatic lipogenesis. While the function of ChREBP has been extensively investigated, mechanisms underlying its transcriptional regulation remain largely unknown. We located a conserved POU-binding site within mammalian ChREBP promoters, and demonstrated that the POU homeodomain protein Oct-1 binds to this site in the human HepG2 cell line. Oct-1 transfection significantly repressed ChREBP promoter activity 50-75%. Conversely, knockdown of Oct-1 expression with shRNA significantly increased ChREBP expression levels. Furthermore, insulin treatment resulted in a two-fold activation of ChREBP promoter activity, and stimulated endogenous ChREBP expression. We found that the stimulatory effect of insulin on the ChREBP promoter is at least partially dependent on the presence of the POU-binding site, and that insulin treatment reduced Oct-1 expression. Our observations identify Oct-1 as a transcriptional repressor of ChREBP, and suggest that insulin stimulates ChREBP expression via attenuating the repressive effect of Oct-1.
19

Descripción y análisis del grosor de la capa de fibras nerviosas retinianas obtenidos mediante tomografía de coherencia óptica en pacientes sometidos a cirugía combinada de glaucoma

Álvarez Bulnes, Olga 20 September 2010 (has links)
INTRODUCCIÓN El glaucoma es una neuropatía óptica progresiva multifactorial. Se observa una disminución de la capa de fibras nerviosas retinianas (CFNR) que puede ser medida mediante tomografía de coherencia óptica (OCT). Se ha realizado un estudio prospectivo de los cambios en el grosor de la CFNR en ojos de pacientes con glaucoma sometidos a cirugía combinada, facoemulsificación asociada a esclerotomía profunda no perforante. Estos cambios también se han comparado con los cambios de la CFNR en ojos no intervenidos. MATERIAL Y MÉTODOS Se incluyeron ojos de pacientes con glaucoma que se distribuyeron en dos grupos. Uno de los ojos se sometió a cirugía combinada y se incluyó como caso. El ojo contralateral se incluyó como control. A estos pacientes se les realizaron dos mediciones del grosor de la CFNR utilizando el OCT Cirrus® (Carl Zeiss Meditec Inc., Dublín, California, USA), una antes y otra un mínimo de dos meses después de la intervención. Los resultados se han analizado mediante la t de Student dado que son datos apareados y se ha aplicado la corrección de Bonferroni puesto que se realizan múltiples comparaciones. RESULTADOS Al comparar los ojos intervenidos de cirugía combinada con los no intervenidos, no se han observado cambios en el grosor de la CFNR que sean significativos. Tampoco existen diferencias significativas entre el grosor antes y después de la cirugía por lo que la OCT no ha demostrado utilidad en la monitorización del éxito o el fracaso de la cirugía combinada a corto plazo. Tampoco se ha determinado si la calidad de la imagen tiene un papel en el cambio de grosor de la CFNR entre tomografías. / INTRODUCTION Glaucoma is a progressive optic nerve disease, with multiple factors involved in its development. There is a thinning in the retinal nerve fiber layer (RNFL) that can be measured using the optic coherence tomography. We have done a prospective trial regarding the thickness of the nerve fiber layer in glaucoma patients who underwent combined surgery for both glaucoma and cataract. The changes in the RNFL have also been compared to those in glaucomatous eyes without surgery. MATERIALS AND METHODS The glaucoma patients included were divided in two groups. One of the eyes underwent combined surgery and was included as a case. The fellow eye was included as a control. In all patients, two measurements of the RNFL were obtained using OCT Cirrus® (Carl Zeiss Meditec Inc., Dublin, California, USA), one before surgery, the second one at least two months after the surgery. Results were analised using t Sudent, and Bonferroni correction was also used because of multiple analisis to the same sample was carried out. RESULTS We have not found significant changes in the RNFL thickness by comparing glaucomatous eyes that underwent surgery with those that did not. There are no significant differences between the thickness before and after the surgery, so OCT has not been proved to be useful in monitoring short-term success after combined surgery for glaucoma and cataract. It has not been possible either to determine whether the signal strength has a significant role in the changes in RNFL thickness between OCT.
20

Optical Coherence Tomography Image Analysis of Corneal Tissue

Zaboli, Shiva January 2011 (has links)
Because of the ubiquitous use of contact lenses, there is considerable interest in better understanding the anatomy of the cornea, the part of the eye in contact with an exterior lens. The recent technology developments in high resolution Optical Coherence Tomography (OCT) devices allows for the in-vivo observation of the structure of the human cornea in 3D and at cellular level resolution. Prolonged wear of contact lenses, inflammations, scarring and diseases can change the structure and physiology of the human cornea. OCT is capable of in-vivo, non-contact, 3D imaging of the human cornea. In this research, novel image processing algorithms were developed to process OCT images of the human cornea, in order to determine the corneal optical scattering and transmission. The algorithms were applied to OCT data sets acquired from multiple subjects before, during and after prolonged (3 hours) wear of soft contact lenses and eye patches, in order to investigate the changes in the corneal scattering associated with hypoxia. Results from this study demonstrate the ability of OCT to measure the optical scattering of corneal tissue and to monitor its changes resulting from external stress (hypoxia).

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