The work presented in this thesis focuses on the development of strategies and smart bioactive materials for the treatment of osteoporosis. High and low molecular weight soluble hyaluronic acid-bisphosphonate (HA-BP) derivatives were investigated for their ability to inhibit osteoclasts. Low molecular weight HA-BP (L-HA-BP) was most effective in inhibiting active resorption of both murine and human osteoclasts (without affecting osteoblasts) compared to free bisphosphonate (BP). Precursor monocytes were unaffected, suggesting the specificity of HA-BP towards osteoclasts. This new class of functionalized hyaluronic acid could lead to rapid development of tailor-made pro-drugs for targeted treatment of osteoporosis. Polyphosphoesters (PEP) have been widely studied for their pro-osteoblast effects, primarily due to their involvement in cellular energy production pathway leading to the formation of inorganic phosphates that contribute to mineralized bone. Given that the effect of PEP on human osteoclasts is little studied, this work on poly(ethylene sodium phosphate) (PEP.Na) explores the potential to use PEP.Na as an inhibitor of osteoclast activity for the first time. PEP.Na exposure led to a dose-dependent toxicity of osteoclasts with reduction in their capacity to form resorption pits over 24h. Currently, there is a dearth of in vitro cell-culture systems that can study osteoclast-related resorption and osteoblast-related mineralization in a single co-culture system, and to simultaneously quantify the effects of soluble factors on these processes. Described here, is the development of a novel and simple two-sided co-culture system that can overcome these limitations with reliable and quantifiable readouts. In comparison with traditional one-sided co-culture systems, the two-sided co-culture was able to generate similar readouts for alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP) markers. There is also the advantage of distinctly separate and quantifiable readouts for mineralization and resorption, which has been demonstrated using Pamidronate. Finally, HA-BP was synthesized with pre-determined amounts of BP groups. The BP groups attached to HA allowed the tunable incorporation of BMP-2 in hydrogels. The charge-based affinity of BMP-2 and BP allowed stable incorporation of specific amounts of BMP-2, which could be tuned by the ratio of BP groups. 125I-labelled BMP-2 was loaded into hydrogels and their release was studied. Radioactive measurements revealed the tunable sequestration and controlled release of protein over time. This result was corroborated by ALP measurements of cells exposed to released BMP-2. ALP production was found to be almost 5-fold higher in HA-BP hydrogels loaded with BMP-2 which suggested that the sequestered BMP-2 is not only available to cells but also remains highly potent, even in entrapped form, The release of BMP-2 is dependent upon the rate of diffusion, swelling in hydrogels and degradation pattern of the gels and may assist in the long-term and rapid regeneration of osteoblasts in vitro.

Hyaluronic acid (HA) is a naturally occurring polymer that holds considerable promise for tissue engineering applications. Current cross-linking chemistries often require a coupling agent, catalyst, or photoinitiator, which may be cytotoxic, or involve a multistep synthesis of functionalized-HA, increasing the complexity of the system. With the goal of designing a simpler one-step , aqueous-based cross-linking system, we synthesized HA hydrogels via Diels-Alder “click” chemistry. Furan-modified HA derivates were synthesized and cross-linked via dimaleimide poly(ethylene glycol). By controlling the furan to maleimide molar ratio, both the mechanical and degradation properties of the resulting Diels-Alder cross-linked hydrogels can be tuned. Rheological and degradation studies demonstrate that the Diels-Alder click reaction is a suitable cross-linking method for HA. These HA cross-linked hydrogels were shown to be cytocompatible and may represent a promising material for soft tissue engineering.

Hyaluronic acid (HA) is a naturally occurring polymer that holds considerable promise for tissue engineering applications. Current cross-linking chemistries often require a coupling agent, catalyst, or photoinitiator, which may be cytotoxic, or involve a multistep synthesis of functionalized-HA, increasing the complexity of the system. With the goal of designing a simpler one-step , aqueous-based cross-linking system, we synthesized HA hydrogels via Diels-Alder “click” chemistry. Furan-modified HA derivates were synthesized and cross-linked via dimaleimide poly(ethylene glycol). By controlling the furan to maleimide molar ratio, both the mechanical and degradation properties of the resulting Diels-Alder cross-linked hydrogels can be tuned. Rheological and degradation studies demonstrate that the Diels-Alder click reaction is a suitable cross-linking method for HA. These HA cross-linked hydrogels were shown to be cytocompatible and may represent a promising material for soft tissue engineering.

Synthetic glycopeptides have attracted much interest in the biomedical field due to their structural similarities to the natural glycopeptides or glycoproteins. It is still difficult to synthesize glycopeptides with greater efficiency and ring opening polymerization remains an effective way to do so. Proteoglycans are a special class of glycoproteins with glycosaminoglycan chains. In this study, I tried to do controlled ring opening polymerization of Hyaluronic acid derivatives with smaller to higher molecular weight while avoiding side reactions. It is challenging to work with higher molecular weight molecules and do a click reaction in water effectively. Making nanopolymers with a desired size, studies of the characteristics, and how to build nanocarriers for drug delivery application was the focus of this work. Polymeric characteristics, e.g., modification and polymer formation were studied by nuclear magnetic resonance technique; Particle size was studied by dynamic light scattering and the loading of rhodamine B encapsulated into the polymer was measured by confocal imaging technique.

The effect of absorbable packing on the healing of nasal respiratory epthelium after endoscopic sinus surgery (ESS) was examined in a diseased sheep model. Full thickness injuries were created on the lateral nasal wall of sheep infested with Oestrus ovi. Sites of injury were packed on one side with hyaluronic acid (HA) packing or hyaluronic acid packing impregnated with insulin-like growth factor- 1 (HA+IGF1) in a randomized fashion. The opposite side was left unpacked as a control. Biopsies were obtained for light microscopy, scanning electron microscopy, and ciliary beat frequency (CBF) analysis over a period of 16 weeks. Statistical analysis of results was performed in order to determine if any intervention had any impact on healing and to determine if there was any correlation between extent of regeneration as assessed by electron microscopy and CBF. Furthermore assessment of the effect of isotonic and hypertonic saline on ciliary beat frequency was performed in healthy human volunteers. Reepithelialization was increased in the HA+IGF1 group compared to the HA group and controls at eight weeks after injury but not at later time points. Cilial regeneration was improved in the HA+IGF1 group compared to the HA group and controls at 16 weeks. CBF was noted to be worse at the eight week time point with the HA+IGF1 group compared to the HA group and controls, but no other statistically significant effects on CBF were noted. This most likely represents a spurious finding. Wide distributions of CBF results were noted, reflecting numerous missing data points due to methodological difficulties. There was a trend noted toward increased CBF with improved grades of reciliation, although this correlation was not statistically significant. However this trend was supported by the finding of statistically significant differences between individual and combined grades of reciliation. Hypertonic saline was found to have a ciliostimulatory effect when compared to normal saline at 5 minutes after administration in healthy human subjects. This effect had disappeared by 60 minutes after administration. It is suggested that the presence of insulin-like growth factor- 1 at the time of mucosal injury improves epithelial regeneration in the short term, but is not sufficient for this effect to be sustained. This improved early epithelial regeneration forms a foundation for cilial regeneration, as is reflected in an improved grade of reciliation at 16 weeks. Our interventions had no effect on CBF, and various experimental problems made it difficult to provide further comment on CBF results. There is evidence that CBF improves as the grade of cilial regeneration improves following ESS. Furthermore, hypertonic saline appears to also have a positive impact on CBF, which is likely to reflect changes in the rheological properties of mucous. A number of possible avenues of enquiry are delineated and recommendations for future research are outlined. / Thesis (M.S.)--Department of Surgery, 2005.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 5 uppsatser.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2006. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2008. / Title from first page of PDF file (viewed June 5, 2008). Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (p. 117-132).

Orientador: Silvana Artioli Schellini / Resumo: OBJETIVO: Avaliar a eficiência da injeção de ácido hialurônico (AH) ou de soro fisiológico (SF), aplicados no subcutâneo da pálpebra inferior de portadores de ectrópio cicatricial, visando à correção não cirúrgica do mal posicionamento palpebral. MÉTODOS: este foi um estudo prospectivo, intervencionista, envolvendo 23 pálpebras de 15 portadores de ectrópio cicatricial, divididos aleatoriamente em dois grupos: G1 (13 pálpebras) no qual foram feitas quatro aplicações de 4ml de SF (Cloreto de Sódio 0,9%, Equiplex, Goiás, Brasil), associado a 1ml de cloridrato de lidocaína a 2,0% sem vasoconstritor (Xylestesin®, Cristália, São Paulo, Brasil), em intervalos de uma semana entre as aplicações; e G2 (10 pálpebras) que receberam aplicação de 1 ml de AH (Restylane® Lidocaine, Q med, Uppsala, Suécia) em aplicação única. Foram avaliadas as variáveis demográficas dos participantes, as queixas, o grau do ectrópio, o grau de flacidez palpebral, a localização do ectrópio, além de avaliações quantitativas realizadas utilizando-se a fotodocumentação sistematizada dos olhos dos pacientes, 30 dias após a primeira aplicação no G1 e 7 e 30 dias após as aplicações do G2. As imagens obtidas foram transferidas para um computador e avaliadas utilizando-se o programa Image J, avaliando-se a distância da pálpebra inferior até o reflexo corneano (DMR2), distância limbo-margem (LM), ângulo da comissura interna (AI) e externa (AE), área total (AT), lateral (AL) e medial (AM). As áreas a serem avaliadas for... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: PURPOSE: Evaluate the efficiency of injection of hyaluronic acid (HA) or saline solution (SF) applied to the lower eyelid subcutaneous, aiming at the non-surgical correction of cicatricial ectropion. METHODS: This was a prospective study involving 23 eyelids of 15 patients with cicatricial ectropion, randomly divided into two groups: G1 (13 eyelids) with four applications of 4ml of SF (Sodium Chloride 0.9%, Equiplex, Goiás , Brazil), associated to 1ml of lidocaine hydrochloride 2% without vasoconstrictor (Xylestesin®, Cristália, São Paulo, Brazil), with a one-week interval between applications; and G2 (10 eyelids) which received single application of 1 ml of AH (Restylane® Lidocaine, Q med, Uppsala, Sweden). Demographic variables, complaints, ectropion degree, eyelid flaccidity degree, ectropion location, and quantitative assessments using the systematized photodocumentation of patients eyelids 30 days after the first application in G1 and 7 and 30 days after applications in G2 were studied. The images were transferred to a computer and evaluated using the Image J program and the distance between the lower eyelid margin to corneal reflex (DMR2), limbus margin distance (LM), internal angle (IA) and external angle (EA), total (TA), lateral (LA) and medial areas (MA) were analyzed. The area measurements were delimited by a line between the two commissures and along the lid margin of the lower eyelid. The evaluations were done without traction and with traction downward of the lo... (Complete abstract click electronic access below) / Mestre