Orientador: José Carlos Peraçoli / Banca: Paulo Sérgio França / Banca: Marcos Consonni / Resumo: O diagnóstico diferencial das síndromes hipertensivas durante a gestação é baseado nos achados clínicos, laboratoriais e exames de fundo de olho. O Doppler da artéria oftálmica é um método objetivo que pode facilitar o diagnóstico da hipertensão durante a gestação, identificando suas diferentes manifestações. Diferenciar, por meio do Doppler da artéria oftálmica, as gestantes portadoras de pré-eclâmpsia daquelas portadoras de hipertensão arterial crônica. Estudo transversal de 30 gestantes com hipertensão arterial crônica e 31 gestantes com pré-eclâmpsia (National High Blood Pressure Education Program, 2000) realizado no terceiro trimestre de gestação. Todas as gestantes realizaram proteinúria de 24 horas e Doppler da artéria oftálmica direita. A dopplervelocimetria da artéria oftálmica avaliou os seguintes parâmetros, para quantificação da onda de velocidade de fluxo: índice de resistência (IR), índice de pulsatilidade (IP), pico de velocidade sistólica (PVS), pico de velocidade diastólica (PVD), velocidade diastólica final (VDF) e razão entre picos de velocidade (RPV). Os resultados foram submetidos à análise estatística, considerando-se significativos quando p<0,05. As médias dos índices Doppler das gestantes com pré-eclâmpsia e hipertensão arterial crônica foram respectivamente: IR= 0,649 + 0,067; 0,718 + 0,077, IP= 1,205 + 0,326; 1,555 + 0,373, PVS: 34,280 + 9,306; 35,206 + 9,941, PVD: 26,513 + 10,060; 19,752 + 5,847, VDF: 11,951 + 4,060; 9,696 + 3,223 e RPV: 0,77 + 0,16; 0,57 + 0,11. Os índices de resistência e de pulsatilidade da artéria oftálmica das gestantes com pré-eclâmpsia foram significativamente inferiores aos das gestantes hipertensas crônicas. Observou-se tendência de aumento dos valores do pico de velocidade diastólica e da velocidade diastólica final de gestantes com pré-eclâmpsia, quando comparadas... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The differential diagnosis of pregnancy hypertensive syndromes is based on clinical, laboratorial as well as fundoscopy findings. The ophthalmic artery Doppler is an objective method which may facilitate the diagnosis of hypertension during pregnancy, distinguishing its several manifestations. Differentiate, through ophthalmic artery Doppler, women with preeclampsia from those with chronic arterial hypertension. Cross-sectional study which analyzed 30 pregnant women with chronic arterial hypertension and 31 with preeclampsia (National High Blood Pressure Education Program 2000) during the third trimester of pregnancy. 24-hour urine was checked for proteinuria in all patients and the ophthalmic artery Doppler examination was taken by them. The Doppler velocimetry of the ophthalmic artery has evaluated the following parameters for quantification of flow velocity waveforms: resistance index (RI), pulsatility index (PI), peak systolic velocity (PSV), peak diastolic velocity (PDV), end diastolic velocity (EDV) and ratio between the velocity peaks (PR). Median and standard deviation were applied to the data. The average of the Doppler indexes on pregnant women with preeclampsia and chronic hypertension was respectively: RI= 0,649 + 0,067; 0,718 + 0,077, PI= 1,205 + 0,326; 1,555 + 0,373, PSV: 34,280 + 9,306; 35,206 + 9,941, PDV: 26,513 + 10,060; 19,752 + 5,847, EDV: 11,951 + 4,060; 9,696 + 3,223 e PR: 0,77 + 0,16; 0,57 + 0,11. The resistance and pulsatility indexes of the ophthalmic artery Doppler on women with preeclampsia were significantly inferior to those with chronic hypertension. It was observed that there is a tendency of increasing the values of the peak of diastolic velocity in addition to the end diastolic velocity on women with preeclampsia when compared to those with chronic hypertension. The ratio of the peak of velocity was significantly superior on pregnant women... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2014-06-11T19:29:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-08-02Bitstream added on 2014-06-13T20:39:43Z : No. of bitstreams: 1 silvanetto_jp_me_botfm.pdf: 171059 bytes, checksum: 5be723f02aec00d3b022f3b787b8a279 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O diagnóstico diferencial das síndromes hipertensivas durante a gestação é baseado nos achados clínicos, laboratoriais e exames de fundo de olho. O Doppler da artéria oftálmica é um método objetivo que pode facilitar o diagnóstico da hipertensão durante a gestação, identificando suas diferentes manifestações. Diferenciar, por meio do Doppler da artéria oftálmica, as gestantes portadoras de pré-eclâmpsia daquelas portadoras de hipertensão arterial crônica. Estudo transversal de 30 gestantes com hipertensão arterial crônica e 31 gestantes com pré-eclâmpsia (National High Blood Pressure Education Program, 2000) realizado no terceiro trimestre de gestação. Todas as gestantes realizaram proteinúria de 24 horas e Doppler da artéria oftálmica direita. A dopplervelocimetria da artéria oftálmica avaliou os seguintes parâmetros, para quantificação da onda de velocidade de fluxo: índice de resistência (IR), índice de pulsatilidade (IP), pico de velocidade sistólica (PVS), pico de velocidade diastólica (PVD), velocidade diastólica final (VDF) e razão entre picos de velocidade (RPV). Os resultados foram submetidos à análise estatística, considerando-se significativos quando p<0,05. As médias dos índices Doppler das gestantes com pré-eclâmpsia e hipertensão arterial crônica foram respectivamente: IR= 0,649 + 0,067; 0,718 + 0,077, IP= 1,205 + 0,326; 1,555 + 0,373, PVS: 34,280 + 9,306; 35,206 + 9,941, PVD: 26,513 + 10,060; 19,752 + 5,847, VDF: 11,951 + 4,060; 9,696 + 3,223 e RPV: 0,77 + 0,16; 0,57 + 0,11. Os índices de resistência e de pulsatilidade da artéria oftálmica das gestantes com pré-eclâmpsia foram significativamente inferiores aos das gestantes hipertensas crônicas. Observou-se tendência de aumento dos valores do pico de velocidade diastólica e da velocidade diastólica final de gestantes com pré-eclâmpsia, quando comparadas... / The differential diagnosis of pregnancy hypertensive syndromes is based on clinical, laboratorial as well as fundoscopy findings. The ophthalmic artery Doppler is an objective method which may facilitate the diagnosis of hypertension during pregnancy, distinguishing its several manifestations. Differentiate, through ophthalmic artery Doppler, women with preeclampsia from those with chronic arterial hypertension. Cross-sectional study which analyzed 30 pregnant women with chronic arterial hypertension and 31 with preeclampsia (National High Blood Pressure Education Program 2000) during the third trimester of pregnancy. 24-hour urine was checked for proteinuria in all patients and the ophthalmic artery Doppler examination was taken by them. The Doppler velocimetry of the ophthalmic artery has evaluated the following parameters for quantification of flow velocity waveforms: resistance index (RI), pulsatility index (PI), peak systolic velocity (PSV), peak diastolic velocity (PDV), end diastolic velocity (EDV) and ratio between the velocity peaks (PR). Median and standard deviation were applied to the data. The average of the Doppler indexes on pregnant women with preeclampsia and chronic hypertension was respectively: RI= 0,649 + 0,067; 0,718 + 0,077, PI= 1,205 + 0,326; 1,555 + 0,373, PSV: 34,280 + 9,306; 35,206 + 9,941, PDV: 26,513 + 10,060; 19,752 + 5,847, EDV: 11,951 + 4,060; 9,696 + 3,223 e PR: 0,77 + 0,16; 0,57 + 0,11. The resistance and pulsatility indexes of the ophthalmic artery Doppler on women with preeclampsia were significantly inferior to those with chronic hypertension. It was observed that there is a tendency of increasing the values of the peak of diastolic velocity in addition to the end diastolic velocity on women with preeclampsia when compared to those with chronic hypertension. The ratio of the peak of velocity was significantly superior on pregnant women... (Complete abstract click electronic access below)

Two specific drug-delivery applications were sought in this work using polyamidoamine (PAMAM) dendrimers. One drug-delivery system used a novel dendrimer hydrogel (DH) for sustained delivery of anti-glaucoma drugs. In this work, PAMAM G3.0 dendrimers were covalently bonded with poly(ethylene glycol) (PEG­12000) molecules which were subsequently acrylated, resulting in photocurable DH conjugates. For pharmacological studies, DH were loaded with a solution of intraocular pressure lowering drugs, brimonidine and timolol maleate, and were characterized for in vitro release and ex vivo transport and uptake. DH formulations were shown to increase the loading of drug molecules, increase transcorneal drug delivery, and exhibit sustained-delivery of drug molecules. A second drug-delivery system, utilizing cell-surface engineering, intended to increase the targeting ability of highly toxic anti-cancer drugs to curtail systemic effects. In particular, Qdots and 5-(aminoacetamido) fluorescein-labeled polyamidoamine dendrimer G4.5, both of which were coated with amine-derivatized polyethylene glycol, were immobilized to the sodium periodate-treated surface of RAW264.7 macrophages through a transient Schiff base linkage. Further, a reducing agent sodium cyanoborohydride was applied to reduce Schiff bases to stable secondary amine linkages. The distribution of nanoparticles on the cell surface was observed by fluorescence microscopy and was found to be dependent on the stability of the linkages tethering nanoparticles to the cell surface.

<p> Photoresponsive polymers can act as controllable drug delivery systems that may revolutionize ophthalmic drug delivery for disease treatment in the posterior segment of the eye. Localized, controlled drug delivery devices have significant therapeutic advantages for treating diseases of back of the eye by increasing patient compliance and maintaining therapeutic levels of drug in the tissue. Sustained-release delivery systems that respond to light/laser stimuli are under development to control the rate of delivery resulting in a tuneable treatment profile ideal for retinal diseases. The use of light as a crosslinking mechanism has the potential to create unique materials with controllable swelling, degradation and diffusion properties. </p> <p> This thesis investigates the synthesis and development of universal, graftable PEG-anthracene molecules and their applications in photosensitive alginate and hyaluronate (HA) "photogels". Anthracene undergoes reversible dimerization with wavelengths above 300 nm and de-dimerization/dissociation below 300 nm; due to its well-understood chemistry and symmetry, it was used as a starting point and proof-ofconcept for the synthesis of reversible dimerizing crosslinkers that may be generically grafted to different polymers to cause crosslinking/decrosslinking. After synthesis, watersoluble PEG-anthracene macromolecules were grafting via carbodiimide chemistry to the carboxyl groups along the polymer backbone of alginate and HA at various densities to create viscous liquids or gels with good handling properties. </p> <p> Light irradiation can be used to control the swelling and effective crosslinking density of the photogels which in tum can control drug delivery from photocrosslinked hydro gels as illustrated through the decrease or increase in the delivery of a variety of low molecular weight (<1000 Da) and high molecular weight (>10,000 Da) model drug compounds from both alginate and HA photogels with various light treatments. Novel loading mechanisms were developed through the loading of compounds into uncrosslinked gels followed by crosslinking 365 nm exposures to "lock" in the model drug compounds. Diffusion coefficients effectively compared the different systems showing increase exposures of 365 nm resulted in greater decrease in release of compounds demonstrating the ability to fine-tune release rates. Different formulations and control gels demonstrate a variety of different release profiles. The photogels were valuable long-term controlled release systems (>80 days) that also demonstrate high cytocompatibility when grown with ophthalmic cell lines. </p> <p> Novel photoresponsive biomaterials for smart delivery of therapeutics which use light-controlled crosslinking and decrosslinking mechanisms have been developed. The PEG-anthracene graftable photocrosslinkers show the ability to introduce photocontrolled crosslinking into hydrogel systems. While anthracene as the photodimerizer and alginate and HA as the bulk materials are used as a proof-of-concept in this work, this grafting system can be further manipulated to include new photosensitive dimerizers and other applicable polymers. The ability to use light stimuli to control release rates in a continual fashion, rather than having delivery that is strictly on or off, is a valuable finding that may lead to the development of drug delivery systems that can be catered towards individuals and the progression of their disease. </p> / Thesis / Doctor of Philosophy (PhD)

<p> Poly (dimethyl siloxane) (PDMS) has been widely used as a biomaterial in ophthalmic and other applications due to its good compatibility, high mechanical strength and excellent oxygen permeability and transparency. For use as an artificial cornea, contact lens and in other applications, modifications are necessary to improve glucose permeability and wettability for cell and tear protein and mucin interactions through modification with hydrophilic functional groups or polymers. Poly (N-isopropyl acrylamide) (PNIPAAM) is a biocompatible and hydrophilic polymer that has been extensively studied in controlled drug release applications due to its lower critical solution temperature (LCST) phenomenon. In this study, a composite interpenetrating polymer network (IPN) of PDMS and PNIPAAM was formed to generate material with reasonable oxygen and glucose permeability as well as improved wettability and mechanical properties compared to the PDMS and PNIPAAM homopolymers.</p> <p> Semi-IPNs, with low water uptake and mechanical strength, were found not to be suitable as biomaterials. Vinyl terminated PDMS/PNIPAAM IPNs had reasonable water uptake and excellent tensile stress and strain, but low glucose permeability (< 10^-10 cm^2/s). Hydroxyl terminated PDMS/PNIPAAM IPNs (PDMS-OH IPN) were successfully synthesized with reasonable mechanical properties and significantly higher glucose permeability (~10^-7 cm^2/s). Curing the PDMS-OH film with solvent was found to improve glucose transport.</p> <p> The presence of PNIPAAM in the composite networks was confirmed by FT-IR and Differential Scanning Calorimetry (DSC). Transmission Electron Microscopy (TEM) images verified the structure of interpenetrating networks. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and X-ray Photoelectron Spectroscopy (XPS) suggested that PNIPAAM was also present on the surface and this translated to increased roughness compared with the PDMS control as determined by AFM. The LCST phenomena still remained in the IPN, although the change was not as abrupt as with pure PNIPAAM. These results suggest that the copolymer may be useful as an ophthalmic biomaterial and for controlled drug release applications.</p> / Thesis / Master of Applied Science (MASc)

Ocular drug delivery to the posterior segment of the eye is extremely challenging. The delivery of the pharmaceuticals is made difficult by the numerous barriers that are present in the eye, as well as the isolated nature of the eye. The eye also consists of efficient drainage routes that eliminate the drug that has entered the eye successfully. Because of these reasons, drug delivery to the posterior segment of the eye is challenging and complicated. As a result, conventional eye drops are an inefficient way to deliver the pharmaceuticals to the eye as <5% of the administered dose is delivered to the anterior segment of the eye, and a negligible amount is delivered to the posterior tissues. The work presented in this thesis focuses on the design, synthesis, and characterization of the PLGA nanoparticles as a drug delivery vehicle to treat diseases associated with the posterior segment of the eye. The slow-release formulation was developed using PLGA nanoparticles and synthesized by the Double Emulsion Method (W1-O-W2). The PLGA nanoparticles were optimized by following various protocols and formulations to obtain the highest encapsulation efficacy and desired particle size range by changing the intensity of sonication, speed of ultracentrifugation, composition, and amount of the stabilizer and PLGA nanoparticles. The nanoparticles showed a 97% encapsulation efficiency with Bovine Serum Albumin (BSA) and a particle size of 201 nm. The slow-release formulation was further developed by immobilization of the particles in a thermogelling PNIPAAM scaffold. In vitro drug release results suggest that PNIPAAM containing PLGA nanoparticles produced in this work has the potential to be further developed and used as a drug delivery vehicle for the posterior segment of the eye. / Thesis / Master of Applied Science (MASc)

Yes / The model for delivery of primary eye care in Europe varies from country to country with differing reliance on ophthalmologists, optometrists and dispensing opticians. Comparative analysis of models has tended to focus on interprofessional working arrangements, training and regulatory issues, rather than on whether a particular model is effective for delivering public health goals for that country. National Health Service (NHS) primary eye care services in the UK are predominantly provided under a General Ophthalmic Services (GOS) Contract between the NHS and practice owners (Contractors). Over two-thirds of sight tests conducted in England, Wales and Northern Ireland and all in Scotland are performed under a GOS Contract, however many people entitled to a GOS sight test do not take up their entitlement. The fee paid for sight tests conducted under a GOS Contract in England, Wales and Northern Ireland does not cover the full cost of conducting the examination. The shortfall must be made up through profits of sale of optical appliances but this business model can be a deterrent to establishing practices within socioeconomically deprived communities, and can also be a barrier to uptake of sight tests, even though many people are entitled to a NHS optical voucher towards the cost of spectacles or contact lenses. This paper critiques the GOS Contracts within the UK. We argue that aspects of the way the GOS Contract is implemented are contrary to the public health interest and that different approaches are needed to address eye health inequalities and to reduce preventable sight loss.

Eye disorders are on the rise as a result of an ageing population, an increasing obesity problem and a growth in the number of diabetic patients. Conventional ophthalmic formulations do not maintain therapeutic drug concentration in the target tissues for a long duration due to the physiological and anatomical eye barriers. Novel delivery systems such as nanoparticles have been explored to enhance the delivery of therapeutic agents to the eye. These delivery systems have in general been assessed using in-vivo animal models, despite ethical concerns for animal wellbeing. The aims of this thesis were to synthesise and characterise four amphiphilic polymers, subsequently prepare and characterise four nano sized polymeric self-assemblies loaded with triamcinolone acetonide (TA), develop an in-vitro porcine eye model and to evaluate the permeation of nano sized self-assemblies using the developed model. Four comb-shaped amphiphilic polymers (Pa5, Pa5-MPEG, Ch5 and Da10) were synthesised with a high yield (>81%) and good reproducibility. These polymers formed spontaneous positive self-assemblies in aqueous media (114-314 nm). The mean hydrodynamic diameters of the positive spontaneous self-assemblies entrapping TA were in the range of 200–334 nm loading high concentrations (455-1263 μg mL-1) of TA, much greater than the TA inherent aqueous solubility or concentrations achieved using conventional solubilisers. A porcine in-vitro eye model was developed to assess drug permeation through anterior and posterior ocular tissues. The model was partially validated using tritiated water and a series of hydrophilic markers with increasing molecular weights. The integrity of porcine ocular tissue was checked by monitoring the permeation of tritiated water to ensure the membrane intactness. Tritiated water permeation at 15 min was exploited as a potential method to normalise drug flux, as tritiated water percentage permeation at 15 min had an inverse relationship with tissue thickness (R2 = 0.66), to reduce the inherent variability between tissue samples thus increasing the accuracy of the in-vitro eye model. Four markers (fluorescein sodium salt, 4, 10 and 20 kDa FITC-dextran) were used for the purpose of investigating the effect of increasing molecular weight on ocular tissue permeability. The permeability of the markers displayed an inverse relationship and abrupt decline with Mw in terms of the permeability through scleral and corneal tissues of human and porcine and the molecular weight of the markers. The developed porcine in-vitro eye model showed good correlation with the human in-vitro model providing strong evidence it can be used to screen potential formulations before testing in-vivo. The TA loaded self-assemblies and a few chemical enhancers (glutamic acid, tween 80, chitosan, Pa5 and elevate temperature (45 °C)), selected to assist drug delivery via two routes (paracellular and transcellular), were tested using the developed in-vitro eye model. The results showed there was no marker permeation enhancement effect in porcine and human ocular tissues using chemical enhancers. In summary, a porcine in-vitro eye model was developed to assess hydrophobic and hydrophilic penetrant permeation across anterior and posterior ocular tissues. The porcine in-vitro eye model showed good correlation with the human in-vitro model providing strong evidence that the porcine in-vitro eye model can be used to screen potential formulations before testing in-vivo using the porcine model which ultimately might correlate well with the in-vivo human responses. Although TA self-assemblies did not significantly increase drug flux through human or porcine scleral tissues, it might be of interest for ophthalmic topically administered formulations due to their positive charge and small nano size.

Nephropathic cystinosis is a rare autosomal recessive disease characterised by raised lysosomal levels of cystine in the cells of almost all organs. It is treated by regular oral and topical administration of the aminothiol, cysteamine(Cystagon™), which possesses an offensive taste and smell. The oral form frequently causes emesis,and should be administered every six hours to be maximally effective. The topical eye drop treatment requires hourly application to be most effective.In an attempt to reduce this frequency and improve the treatment, the preparation and evaluation of three alternative cysteamine containing formulations (suppositories, long-acting ophthalmic gels and an inhaler) was undertaken. The physiochemical properties, stability and release profiles of the active (cysteamine or phe conjugate) from the formulations were evaluated. The suppositories released cysteamine over a 20-40 minute period with a T75= 10-13minutes. They were most stable at 4°C. The analysis of the ophthalmic gels demonstrated that a weak gel network was formed at low shear stress, the bioadhesion of the gel was increased with inclusion of a cysteamine derivative (e.g.mean force of 0.067N compared to 0.107N with compound included) and eight-hour, first order release from the gel was observed. There was significant adhesion observed between the ophthalmic gels and bovine corneal tissue. The pulmonary microspheres were spherical and within the optimum size range for deep lung delivery (1-5μm). However, Andersen Cascade Impactor analysis revealed poor deep lung penetration. In conclusion, these results demonstrated that more development work was required to produce a useful pulmonary formulation of cysteamine, however, formulation of an ocular applicable gel or suppository was readily achievable. The suppository preparations may be particularly beneficial for the treatment of infants, whilst the ophthalmic gel preparations could be developed for daily or overnight use. With respect to pulmonary delivery, microspheres in the optimum size range were produced. However, deep lung targeting was prevented by static agglomeration, which requires further investigation.

<p>Optical coherence tomography (OCT) is a noninvasive three-dimensional interferometric imaging technique capable of achieving micrometer scale resolution. It is now a standard of care in ophthalmology, where it is used to improve the accuracy of early diagnosis, to better understand the source of pathophysiology, and to monitor disease progression and response to therapy. In particular, retinal imaging has been the most prevalent clinical application of OCT, but researchers and companies alike are developing OCT systems for cardiology, dermatology, dentistry, and many other medical and industrial applications. </p><p>Adaptive optics (AO) is a technique used to reduce monochromatic aberrations in optical instruments. It is used in astronomical telescopes, laser communications, high-power lasers, retinal imaging, optical fabrication and microscopy to improve system performance. Scanning laser ophthalmoscopy (SLO) is a noninvasive confocal imaging technique that produces high contrast two-dimensional retinal images. AO is combined with SLO (AOSLO) to compensate for the wavefront distortions caused by the optics of the eye, providing the ability to visualize the living retina with cellular resolution. AOSLO has shown great promise to advance the understanding of the etiology of retinal diseases on a cellular level.</p><p>Broadly, we endeavor to enhance the vision outcome of ophthalmic patients through improved diagnostics and personalized therapy. Toward this end, the objective of the work presented herein was the development of advanced techniques for increasing the imaging speed, reducing the form factor, and broadening the versatility of OCT and AOSLO. Despite our focus on applications in ophthalmology, the techniques developed could be applied to other medical and industrial applications. In this dissertation, a technique to quadruple the imaging speed of OCT was developed. This technique was demonstrated by imaging the retinas of healthy human subjects. A handheld, dual depth OCT system was developed. This system enabled sequential imaging of the anterior segment and retina of human eyes. Finally, handheld SLO/OCT systems were developed, culminating in the design of a handheld AOSLO system. This system has the potential to provide cellular level imaging of the human retina, resolving even the most densely packed foveal cones.</p> / Dissertation