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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.
1

Secretion of Marker Proteins from Alginate-Poly-L-Alginate Microcapsules and Hydroxythely Methacrylate-Methyl Methacrylate Capsules

Tse, May 03 1900 (has links)
The objective of this study was to encapsulate cell lines that secrete marker proteins that cover a large molecular weight range (M^r from 45,000 to 300,000) and monitor the secretion of the marker proteins from alginate-poly-L-lysine-alginate (APA) microcapsules and hydroxyethyl methacrylatemethyl methacrylate (HEMA-MMA) thermoplastic capsules. Different parameters for the APA microcapsules, such as the duration of poly-L-lysine (PLL) and sodium citrate treatment, the initial cell density for encapsulation was studied, and their effects on secretion rate and cell proliferation were closely examined. Cell lines used for encapsulation secreted human growth hormone (hGH) (M^r 45,000), β-hexosaminidase (β-hexo.) (M^r 120,000) and β-glucuronidase (β-gluc.) (M^r 300,000). Monitoring the secretion rates, as well as the distribution of the marker proteins within the microcapsules following encapsulation enabled the permeability of the membrane to be assessed over one month in culture. Encapsulation of cell lines in both types of capsules was effective in producing viable cells capable of proliferating within a semi-permeable membrane. Encapsulating cells in single-coated APA microcapsules at 4°C, treated with 10 minutes PLL, 20 minutes sodium citrate and at a cell density of 2x10^6 cells/ml alginate was found to provide the most optimal conditions for prolonged viability of and stable secretion by the recombinant cells. Human growth hormone diffused readily across the capsule membrane into the culture media from both APA and HEMA-MMA capsules, at rates similar to the non-encapsulated cells. Human growth hormone did not accumulate in the intracapsular space in significant quantities. β-glucuronidase and β-hexosaminidase could diffuse across APA capsule membrane, but not across HEMA-MMA capsule membrane into surrounding media. β-glucuronidase secretion from APA microcapsules was 8-fold lower than non-encapsulated cells. β-hexosaminidase secretion from APA microcapsules was 4.5-fold lower than non-encapsulated cells. Slight retention of both β-glucuronidase and β-hexosaminidase was observed in the intracapsular space of APA capsules. HEMA-MMA capsules completely blocked the secretion of both β-glucuronidase and β-hexosaminidase out of the capsule. Massive accumulation of both kinds of secretory enzymes was found in the intracapsular space of HEMA-MMA capsules. This indicated APA microcapsules have a molecular weight cut-off of >300,000 whereas HEMA-MMA microcapsules have a molecular weight cut-off of <120,000. / Thesis / Master of Science (MS)
2

Clinical pharmacology of infusion fluids

Hahn, Robert G. January 2012 (has links)
Fluids are used for intravenous infusion during practically all surgeries, but several different compositions are available on the market. Crystalloid fluids comprise lactated or acetated Ringer solutions, normal saline, Plasma-Lyte, hypertonic saline, and glucose. They lack allergic properties but are prone to cause peripheral tissue oedema. Their turn­ over is governed by physiological factors such as dehydration and drug effects. Colloid fluids include hydroxyethyl starch, albumin, dextran, and gelatin. These fluids have various degrees of allergic properties and do not promote peripheral oedema. Their half-life is usually about hours. Factors increasing the turnover rate are poorly known but might include inflammatory states. Current debates include the widespread use of normal saline, which should be replaced by Ringer’s or Plasma-Lyte in most situations, and the kidney damage associated with the use of starch in septic patients. New studies show that hypertonic saline does not improve survival or neurological damage in prehospital care.
3

Desenvolvimento e caracterização de uma resina adesiva experimental acrescida de hidroxietil acrilamida / Development and characterization of an experimental adhesive with the addition of hydroxyethil acrylamide

Rodrigues, Stefani Becker January 2013 (has links)
O objetivo do presente estudo foi desenvolver e caracterizar resinas adesivas contendo hidroxietil acrilamida (HEAA). Três grupos de resinas adesivas foram formulados, GHEAA33% (33,3% de HEAA + 66,6% de bisfenol A glicedil dimetacrilato - BisGMA), GHEAA50% (50% de HEAA + 50% de BisGMA) e GHEMA (33,3% de hidroxietil metacrilato - HEMA + 66,6% de BisGMA). Parâmetros como resistência à flexão (n= 12), grau de inchamento (n= 3), temperatura de transição vítrea (n= 3) e degradação em solvente (n= 5) foram avaliados de cada resina adesiva. Em adição foi avaliado com calorimetria exploratória diferencial (DSC), o processo de polimerização das resinas experimentais (n= 3), bem como dos homopolímeros componentes, BisGMA, HEMA, HEAA, HEMA* sem adição de etil 4- dimetilaminobenzoato (EDAB) e HEAA* sem adição de EDAB. Os resultados foram analisados estatisticamente com auxílio de ANOVA de uma via, teste de Tukey e teste t pareado. Todas as resinas adesivas e homopolímeros, exceto HEMA, HEAA* e HEMA*, apresentaram uma alta taxa de polimerização e um alto grau de conversão. Não houve diferença estatística entre as resinas adesivas para a temperatura de transição vítrea e a degradação em solvente (p>0,05). Entretanto, o grupo GHEAA33% apresentou a menor variação de grau de inchamento (p<0,05) e os menores valores de resistência à flexão (p<0,05) quando comparado com o grupo GHEMA. Considerando que a hidroxietil acrilamida foi capaz de promover o aumento do processo de polimerização de resinas adesivas experimentais e, tendo em vista sua potencial resistência à degradação hidrolítica e ainda, com base nos resultados dos demais ensaios, o grupo GHEAA33%, parece reunir as melhores condições de desenvolvimento de resinas adesivas inovadoras. / The purpose of this study was to develop an experimental adhesive resin using hydroxyethyl acrylamide (HEAA). Three groups of experimental resin were formulated, GHEAA33% (33.3% HEAA + 66.6% Bisphenol A glycerolate dimethacrylate- BisGMA), GHEAA50% (50% HEAA + 50% BisGMA), and GHEMA (33.3% 2-Hydroxyethyl methacrylate- HEMA + 66.6% of BisGMA). Parameters such as flexural strength (n= 12), swelling degree (n= 3), glass transition temperature (n= 3), and softening in solvent (n= 5) were evaluated for each adhesive resin. In addition, the polymerization process of each adhesive resin group (n= 3), as well as for the homopolymers, BisGMA, HEMA, HEAA, HEMA* without ethyl 4-dimethylaminobenzoate (EDAB), and HEAA* without EDAB, were also evaluated using differential scanning calorimetry (DSC). The results were analyzed using one way ANOVA, Tukey’s test, and Student’s t-test. For all of the resins and homopolymers evaluated, except for homopolymers HEMA, HEMA* and HEAA* homopolymer, a high rate of polymerization and a high degree of conversion were observed. There was no significant difference (p > 0.05) for the glass transition temperature and for softening in solvent for the adhesive resins assayed. In contrast, the GHEAA33% group exhibited less swelling degree (p < 0.05) and reduced flexural strength (p < 0.05) compared to the GHEMA group. HEAA was also found to promote the polymerization process and was resistant to hydrolytic degradation. Thus, GHEAA33% appears to be a promising alternative for the production of innovative adhesive resins.
4

Desenvolvimento e caracterização de uma resina adesiva experimental acrescida de hidroxietil acrilamida / Development and characterization of an experimental adhesive with the addition of hydroxyethil acrylamide

Rodrigues, Stefani Becker January 2013 (has links)
O objetivo do presente estudo foi desenvolver e caracterizar resinas adesivas contendo hidroxietil acrilamida (HEAA). Três grupos de resinas adesivas foram formulados, GHEAA33% (33,3% de HEAA + 66,6% de bisfenol A glicedil dimetacrilato - BisGMA), GHEAA50% (50% de HEAA + 50% de BisGMA) e GHEMA (33,3% de hidroxietil metacrilato - HEMA + 66,6% de BisGMA). Parâmetros como resistência à flexão (n= 12), grau de inchamento (n= 3), temperatura de transição vítrea (n= 3) e degradação em solvente (n= 5) foram avaliados de cada resina adesiva. Em adição foi avaliado com calorimetria exploratória diferencial (DSC), o processo de polimerização das resinas experimentais (n= 3), bem como dos homopolímeros componentes, BisGMA, HEMA, HEAA, HEMA* sem adição de etil 4- dimetilaminobenzoato (EDAB) e HEAA* sem adição de EDAB. Os resultados foram analisados estatisticamente com auxílio de ANOVA de uma via, teste de Tukey e teste t pareado. Todas as resinas adesivas e homopolímeros, exceto HEMA, HEAA* e HEMA*, apresentaram uma alta taxa de polimerização e um alto grau de conversão. Não houve diferença estatística entre as resinas adesivas para a temperatura de transição vítrea e a degradação em solvente (p>0,05). Entretanto, o grupo GHEAA33% apresentou a menor variação de grau de inchamento (p<0,05) e os menores valores de resistência à flexão (p<0,05) quando comparado com o grupo GHEMA. Considerando que a hidroxietil acrilamida foi capaz de promover o aumento do processo de polimerização de resinas adesivas experimentais e, tendo em vista sua potencial resistência à degradação hidrolítica e ainda, com base nos resultados dos demais ensaios, o grupo GHEAA33%, parece reunir as melhores condições de desenvolvimento de resinas adesivas inovadoras. / The purpose of this study was to develop an experimental adhesive resin using hydroxyethyl acrylamide (HEAA). Three groups of experimental resin were formulated, GHEAA33% (33.3% HEAA + 66.6% Bisphenol A glycerolate dimethacrylate- BisGMA), GHEAA50% (50% HEAA + 50% BisGMA), and GHEMA (33.3% 2-Hydroxyethyl methacrylate- HEMA + 66.6% of BisGMA). Parameters such as flexural strength (n= 12), swelling degree (n= 3), glass transition temperature (n= 3), and softening in solvent (n= 5) were evaluated for each adhesive resin. In addition, the polymerization process of each adhesive resin group (n= 3), as well as for the homopolymers, BisGMA, HEMA, HEAA, HEMA* without ethyl 4-dimethylaminobenzoate (EDAB), and HEAA* without EDAB, were also evaluated using differential scanning calorimetry (DSC). The results were analyzed using one way ANOVA, Tukey’s test, and Student’s t-test. For all of the resins and homopolymers evaluated, except for homopolymers HEMA, HEMA* and HEAA* homopolymer, a high rate of polymerization and a high degree of conversion were observed. There was no significant difference (p > 0.05) for the glass transition temperature and for softening in solvent for the adhesive resins assayed. In contrast, the GHEAA33% group exhibited less swelling degree (p < 0.05) and reduced flexural strength (p < 0.05) compared to the GHEMA group. HEAA was also found to promote the polymerization process and was resistant to hydrolytic degradation. Thus, GHEAA33% appears to be a promising alternative for the production of innovative adhesive resins.
5

Desenvolvimento e caracterização de uma resina adesiva experimental acrescida de hidroxietil acrilamida / Development and characterization of an experimental adhesive with the addition of hydroxyethil acrylamide

Rodrigues, Stefani Becker January 2013 (has links)
O objetivo do presente estudo foi desenvolver e caracterizar resinas adesivas contendo hidroxietil acrilamida (HEAA). Três grupos de resinas adesivas foram formulados, GHEAA33% (33,3% de HEAA + 66,6% de bisfenol A glicedil dimetacrilato - BisGMA), GHEAA50% (50% de HEAA + 50% de BisGMA) e GHEMA (33,3% de hidroxietil metacrilato - HEMA + 66,6% de BisGMA). Parâmetros como resistência à flexão (n= 12), grau de inchamento (n= 3), temperatura de transição vítrea (n= 3) e degradação em solvente (n= 5) foram avaliados de cada resina adesiva. Em adição foi avaliado com calorimetria exploratória diferencial (DSC), o processo de polimerização das resinas experimentais (n= 3), bem como dos homopolímeros componentes, BisGMA, HEMA, HEAA, HEMA* sem adição de etil 4- dimetilaminobenzoato (EDAB) e HEAA* sem adição de EDAB. Os resultados foram analisados estatisticamente com auxílio de ANOVA de uma via, teste de Tukey e teste t pareado. Todas as resinas adesivas e homopolímeros, exceto HEMA, HEAA* e HEMA*, apresentaram uma alta taxa de polimerização e um alto grau de conversão. Não houve diferença estatística entre as resinas adesivas para a temperatura de transição vítrea e a degradação em solvente (p>0,05). Entretanto, o grupo GHEAA33% apresentou a menor variação de grau de inchamento (p<0,05) e os menores valores de resistência à flexão (p<0,05) quando comparado com o grupo GHEMA. Considerando que a hidroxietil acrilamida foi capaz de promover o aumento do processo de polimerização de resinas adesivas experimentais e, tendo em vista sua potencial resistência à degradação hidrolítica e ainda, com base nos resultados dos demais ensaios, o grupo GHEAA33%, parece reunir as melhores condições de desenvolvimento de resinas adesivas inovadoras. / The purpose of this study was to develop an experimental adhesive resin using hydroxyethyl acrylamide (HEAA). Three groups of experimental resin were formulated, GHEAA33% (33.3% HEAA + 66.6% Bisphenol A glycerolate dimethacrylate- BisGMA), GHEAA50% (50% HEAA + 50% BisGMA), and GHEMA (33.3% 2-Hydroxyethyl methacrylate- HEMA + 66.6% of BisGMA). Parameters such as flexural strength (n= 12), swelling degree (n= 3), glass transition temperature (n= 3), and softening in solvent (n= 5) were evaluated for each adhesive resin. In addition, the polymerization process of each adhesive resin group (n= 3), as well as for the homopolymers, BisGMA, HEMA, HEAA, HEMA* without ethyl 4-dimethylaminobenzoate (EDAB), and HEAA* without EDAB, were also evaluated using differential scanning calorimetry (DSC). The results were analyzed using one way ANOVA, Tukey’s test, and Student’s t-test. For all of the resins and homopolymers evaluated, except for homopolymers HEMA, HEMA* and HEAA* homopolymer, a high rate of polymerization and a high degree of conversion were observed. There was no significant difference (p > 0.05) for the glass transition temperature and for softening in solvent for the adhesive resins assayed. In contrast, the GHEAA33% group exhibited less swelling degree (p < 0.05) and reduced flexural strength (p < 0.05) compared to the GHEMA group. HEAA was also found to promote the polymerization process and was resistant to hydrolytic degradation. Thus, GHEAA33% appears to be a promising alternative for the production of innovative adhesive resins.
6

Surface Modification of Model pHEMA Contact Lenses with Aptamers for Controlled Drug Release

Shaw, Aakash January 2020 (has links)
An efficient delivery system and patient compliance are two of the most important factors for any drug delivery system design to be successful. The current standard, particularly to the ocular anterior segment, are topical applications including eye drops. However, due to ocular physical barriers including blinking, the varying tear film layers, and the structure of the corneal epithelium, less that 5% of drug reach the target tissue from a single eye drop dose. While most treatment regiments combat this with increased frequency of dosage and higher than needed concentrations, the need for a more efficient and controlled system has been recognized to reduce the risk of possible side effects. Contact lenses (CL) have been a widely discussed potential drug delivery device given their accepted use in the population, their ability to hold drug, as well as their placement on the ocular surface. The current work focuses on testing a novel delivery system using CLs with the incorporation of drug specific oligonucleotide chains known as aptamers on the surface of the lenses. This application of contact lenses is aimed at capitalizing on the strong affinity of aptamers to hold drug on the surface of the lenses until they are applied to the eyes. The aptamers were covalently attached to the surface via the activation of the hydroxyl groups on pHEMA as a model lens material using 1’1-carbonyldiimidazone CDI chemistry and subsequent reaction with the amine group on the 5' end of the aptamer. The presence of aptamers was confirmed using 6-carbofluorescein (6-FAM) fluorescence detection and x-ray photoelectron spectroscopy (XPS). The release of kanamycin B in comparison to regular pHEMA gels using a soaking uptake method was assessed. In this work, aptamers were confirmed through fluorescence to have been successfully reacted onto the surface, however XPS was not able to confirm a consistent reading. This may have been due to low initial amounts of aptamer or uneven distributions along the surface. The efficiency of the aptamer reaction was not tested and would need to be further investigated. The contact angle had a significant change with increased hydrophilicity at 60.7 ± 1.55° compared to 66.6 ± 0.67°, however physically it should not affect wettability. The lower aptamer amounts resulted in no significant difference during drug release. Kanamycin B was detected using liquid chromatography mass spectroscopy (LCMS) with a reverse phase method using a C18 column however quite a few errors in the methodology led to the conclusion that this method of drug release requires further investigation. It is recommended an aptamer-surface reaction efficiency be determined with the use of a much larger starting aptamer amount, as well as a follow up drug release. / Thesis / Master of Applied Science (MASc)
7

A Mixed Biosensing Film Composed of Oligonucleotides and Poly (2-hydroxyethyl methacrylate) Brushes to Enhance Selectivity for Detection of Single Nucleotide Polymorphisms

Wong, April Ka Yee 02 September 2010 (has links)
This work has explored the capability of a mixed film composed of oligonucleotides and oligomers to improve the selectivity for the detection of fully complementary oligonucleotide targets in comparison to partially complementary targets which have one and three base-pair mismatched sites. The intention was to introduce a “matrix isolation” effect on oligonucleotide probe molecules by surrounding the probes with oligomers, thereby reducing oligonucleotide-to-oligonucleotide and/or oligonucleotide-to-surface interactions. This resulted in a more homogeneous environment for probes, thereby minimizing the dispersity of energetics associated with formation of double-stranded hybrids. The mixed film was constructed by immobilizing pre-synthesized oligonucleotides onto a mixed aminosilane layer and then growing the oligomer portion by surface-initiated atom transfer radical polymerization (ATRP) of 2-hydroxy methacrylate (PHEMA). The performance of the mixed film was compared to films composed of only oligonucleotides in a series of hybridization and melt curve experiments. Surface characterization techniques were used to confirm the growth of the oligomer portion as well as the presence of both oligonucleotides and oligomer components. Polyatomic bismuth cluster ions as sources for time-of-flight secondary ion mass spectrometry experiments could detect both components of the mixed film at a high sensitivity even though the oligomer portion was at least 200-fold in excess. At the various ionic strengths investigated, the mixed films were found to increase the selectivity for fully complementary targets over mismatched targets by increasing the sharpness of melt curves and melting temperature differences (delta Tm) by 2- to 3-fold, and by reducing non-specific adsorption. This resulted in improved resolution between the melt curves of fully and partially complementary targets. A fluorescence lifetime investigation of the Cy3 emission demonstrated that Cy3-labeled oligonucleotide probes experienced a more rigid microenvironment in the mixed films. These experiments demonstrated that a mixed film composed of oligonucleotides and PHEMA can be prepared on silica-based substrates, and that they can improve the selectivity for SNP discrimination compared to conventional oligonucleotide films.
8

Reatividade de iso-&alpha;-ácidos e seus derivados hidrogenados frente ao radical 1-hidroxietila: implicações na perda de qualidade sensorial da cerveja / Reativity of iso-&alpha;-acids and its hydrogenated derivatives towards the 1-hydroxyethyl radical: implications in the sensorial quality loss of beer

Almeida, Natália Ellen Castilho de 18 February 2011 (has links)
Os iso-&alpha;-ácidos são os principais constituintes responsáveis pelo sabor amargo da cerveja, sendo estes facilmente degradados durante o seu processo de envelhecimento ou exposição a radiação luminosa, em particular o diastereoisômero trans-. O radical 1-hidroxietila é o radical majoritário formado na cerveja durante o processo de envelhecimento. O presente trabalho descreve a reatividade dos iso-&alpha;-ácidos frente ao radical 1-hidroxetila através do uso da técnica de spin-trapping com detecção por espectroscopia de ressonância paramagnética de elétrons (RPE) e espectrometria de massas (ESI-(+)-MS/MS). Observou-se que ambos os diastereoisômeros cis- e trans-iso-&alpha;-ácidos são degradados na presença do radical 1-hidroxietila com constantes de velocidade aparentes de 1,8 108 e 9,2 109 L mol-1 s-1, respectivamente. A reatividade dos dihidro-iso-&alpha;-ácidos com o radical estudado foi similar à reatividade da mistura diastereoisomérica dos iso-&alpha;-ácidos, apresentando constante de velocidade aparente de 1,5 109 L mol-1 s-1. Os análogos tetrahidro-iso-&alpha;-ácidos não apresentaram reatividade para com o radical 1-hidroxietila, sugerindo os hidrogênios alílicos como sítio reacional. Adicionalmente, os cálculos ab initio por DFT demonstraram que os valores de BDE para os hidrogênios alílicos das cadeias laterais prenila e isohexenoila são equivalentes e, desta maneira, sugerindo a maior reatividade do diastereoisômero trans- a ser creditada a um fator entrópico, já que ambos os grupos estão no mesmo plano espacial. Os produtos de oxidação foram determinados por LC-ESI-MSn e verificou-se a formação dos hidroxi-allo-iso-&alpha;-ácidos, recentemente descritos na literatura. O conjunto de resultados obtidos possibilitou a proposta de mecanismo para processo de oxidação e perda dos ácidos amargos da cerveja, observado no envelhecimento da bebida. / The iso-&alpha;-acids are the main responsible constituents for the bitter taste of beer, they are easily degraded during the aging and light exposed process, specially the trans- diastereoisomer. The 1-hydroxyethyl radical is the major radical produced during the beer aging process. The present work describes the reactivity of iso-&alpha;-acids towards the 1-hydroxyethyl radical as probed by the spin-trapping technique and detected by electron paramagnetic resonance (EPR) and mass spectrometry (ESI-(+)-MS/MS). It was observed that both diastereoisomers cis- and trans-iso-&alpha;-acids are degraded in the presence of 1-hydroxyethyl radical with apparent rate constant of 1.8 108 e 9.2 109 L mol-1 s-1, respectively. The reactivity of dihydro-iso-&alpha;-acids towards the studied radical was similar to the reactivity of the iso-&alpha;-acids diastereoisomeric mixture, showing apparent rate Constant of 1.5 109 L mol-1 s-1. The tetrahydro-iso-&alpha;-acids analogues did not observed reactivity towards the 1-hydroxyethyl radical suggesting the allilic hydrogens as the reaction sites. In addition, the ab initio DFT calculations demonstrated that the BDE values for the allilic hydrogens of the prenyl and isohexenoyl side chains are equivalents and according to that suggesting the higher reactivity of the trans- diastereoisomer to be accounted to an entropic factor since both goups are in the same plane of the space. The oxidation products were determined by LC-ESI-MSn and its was verified the formation of hydroxyl-allo-iso-&alpha;-acids. The data colected allows a mechanism to be proposed for the oxidation process and loss of bitter acids of beer during the beverage aging.
9

Hemodiluição normovolêmica aguda: estudo experimental comparativo utilizando amido hidroxietílico a 6% ou solução de Ringer lactato / Acute normovolemic hemodilution: comparative evaluation with hydroxyethyl starch and Lactated Ringer’s

Otsuki, Denise Aya 18 June 2004 (has links)
Hemodiluição normovolêmica aguda é um procedimento utilizado para diminuir a necessidade de transfusões sangüíneas em diversas cirurgias de grande porte. Poucos trabalhos avaliam as alterações hemodinâmicas e perfusão tecidual através de estudo ecocardiográfico e tonometria gástrica. Foram utilizados 23 porcos (peso 46.6 ± 6.0 kg) anestesiados com quetamina, fentanil e propofol e instrumentados para monitorização hemodinâmica convencional. Os animais foram randomizados em três grupos 30 minutos após estabilização da anestesia: Grupo I (Controle), Grupo II (amido hidroxietílico) e Grupo III (Ringer lactato). Os animais do grupo II e III foram submetidos ao protocolo de hemodiluição com hematócrito alvo de 15%. A retirada de sangue foi realizada em 30 minutos e a expansão plasmática feita simultaneamente com amido hidroxietílico ou Ringer lactato nas proporções de 1:1 ou 1:3 em relação ao sangue retirado. Os parâmetros hemodinâmicos e de oxigenação, pH gástrico, ecocardiografia transesofágica (fração de ejeção através do método Simpson) foram coletados antes da hemodiluição (T0), no fim do procedimento de hemodiluição (T1) e após uma e duas horas (T2, T3). Os dados foram submetidos a análise de variância para medidas repetidas, seguida pelo teste Tukey e teste T student. Resultados: Em relação aos parâmetros do grupo controle, não houve diferença significante durante todo o procedimento. No grupo II e grupo III, houve aumento no índice cardíaco após hemodiluição (T0=5,80±1,46; T1=10,64±1,69 L.min-1.m2 e T0=5,53±1,18, T1=7,91±1,40 L.min-1.m2 respectivamente), e diminuição do índice de resistência vascular sistêmica (T0=1753±336, T1=822±140 dina.s.cm-5.m-2 e T0=1673±566, T1=1026±190 dina.s.cm-5.m-2 respectivamente), ambos estatisticamente significante. A fração de ejeção apresentou aumento significativo após a hemodiluição no grupo II. O pH gástrico diminuiu significativamente no grupo III. O lactato arterial aumentou de forma significante no grupo III após a hemodiluição. A microscopia eletrônica do ventrículo esquerdo mostraram discreta destruição de miofilamentos no grupo II. Houve destruição importante nas miofibrilas no grupo III. Conclusão: Estes resultados sugerem que na hemodiluição moderada a grave, o amido hidroxietílico consegue preservar melhor a estabilidade hemodinâmica do que a solução de Ringer lactato. / Normovolemic acute hemodilution is a procedure utilized to decrease the needs of blood transfusion during a variety of surgical procedures. Nevertheless, there are few works that evaluate its pulmonary effects as well as hemodynamic changes by means of echocardiography and tonometric evaluation. Methods: 23 anesthetized pigs (weight 46.6 ± 6.0 kg) were instrumented for standard hemodynamic monitoring. In order to prevent possible effects of inhaled anesthetics on pulmonary mechanics, intravenous anesthesia was chosen and consisted of ketamine, fentanyl and propofol administered throughout the study. Thirty minutes after anesthesia stabilization animals were randomized in three groups: Group I (Control), Group II (hydroxyethyl starch) and Group III (Lactated Ringer’s). Animals of group II and III were submitted to acute normovolemic hemodilution to reach a pre-established hematocrit around 15%. Blood withdrawal was accomplished in thirty minutes and plasma expansion was performed simultaneously with hydroxyethyl starch or Lactated Ringer’s administered in a proportion of 1:1 or 3:1 in relation to the amount of bloods withdrawn. Hemodynamic, gastric pH, transesophageal echography (ejection fraction, by Simpon method) and oxygen transport were measured before blood withdrawal (T0), at the end of hemodilution (T1), one and two hours after the end of hemodilution (T2, T3). Data were submitted to analysis of Variance for repeated measures followed by the Tukey test and also to a student T test. Results: In regard to all parameters of Group I (Control), there were no significant difference during the whole procedure. In Group II and Group III, there was an increase in cardiac index after hemodilution (T0=5.80±1.46; T1=10.64±1.69 L.min-1.m2 and T0=5.53±1.18, T1=7.91±1.40 L.min-1.m2), and a decrease in systemic vascular resistance index (T0=1753±336, T1=822±140 dyne.s.cm-5.m-2 and T0=1673±566, T1=1026±190 dyne.s.cm-5.m-2), both statistically significant. Ejection Fraction increased significantly after hemodilution in group II. Gastric pH decreased significantly in Group III, and arterial lactate increased significantly after hemodilution in group III. Electron microscopy of left ventricular bipsies showed a slight destruction in filament and preserved myofibrillar ultrastructure in group II. There was important destruction in myofibrillar ultrastructure in group III. Conclusion: These results suggest that in severe hemodilution, hydroxyethyl starch preserves hemonodynamic stability better than Lactate Ringer’s.
10

Nanoemulsões de uso tópico contendo cumestrol : estudos de formulação e permeação cutânea

Argenta, Débora Fretes January 2011 (has links)
O cumestrol é um isoflavonóide presente em diferentes leguminosas como a alfafa, soja e trevo vermelho. Estudos demonstraram uma relevante atividade antioxidante e estrogênica deste composto. Neste contexto, o objetivo deste estudo foi desenvolver nanoemulsões contendo cumestrol visando a sua aplicação tópica. Na primeira fase, nanoemulsões foram obtidas por emulsificação espontânea. Tal procedimento conduziu à obtenção de nanoemulsões monodispersas, confirmado por microscopia eletrônica de transmissão. A viscosidade das formulações permaneceu similar, enquanto que o potencial zeta foi influenciado pela presença dos tensoativos. Após espessamento, as formulações demonstraram um comportamento não-Newtoniano pseudoplástico. Na segunda etapa, o teor de cumestrol nas formulações foi determinado por CLAE. O método foi específico, linear, preciso e exato para quantificação de cumestrol nas formulações desenvolvidas. Os perfis de liberação do cumestrol, através de membrana artificial, demonstraram uma liberação imediata para todas as formulações. Por fim, estudos de permeação/retenção do cumestrol através de pele de orelha suína foram realizados utilizando-se células de difusão de Franz. Os resultados obtidos demonstram um fluxo lento do cumestrol através da pele. O conjunto de resultados obtidos demonstra o efeito da composição sobre as propriedades das formulações e distribuição do cumestrol através das camadas da pele. / Coumestrol is an isoflavonoid present in various legumes such as alfalfa, soybeans, and red clovers. Studies have shown significant estrogenic and antioxidant activities for this compound. With this in mind, the main purpose of this study was to develop nanoemulsion containing coumestrol for topic application. In the first phase, nanoemulsions were obtained by spontaneous emulsification. This procedure yielded monodisperse nanoemulsions, confirmed by transmission electron microscopy. The viscosity of the formulations remained similar, while the zeta potential was influenced by the surfactants. After thickening, the formulations showed a pseudplastic non-Newtonian behavior. In the second step, the coumestrol content in the formulations was determined by HPLC. The method was specific, linear, precise, and accurate for coumestrol quantification in the developed formulations. The coumestrol release profile through artificial membrane showed immediate release for all formulations. Finally, studies of coumestrol permeation/retention through porcine ear skin were performed using Franz diffusion cells. The results showed a slow flow of coumestrol through the skin. The overall results show the effect of the composition on the properties of the formulations and coumestrol distribution through the layers of the skin.

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