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POLYETHYLENE GLYCOL ADDITION DOES NOT IMPROVE EXOGENOUS SURFACTANT FUNCTION IN AN EXPERIMENTAL MODEL OF MECONIUM ASPIRATION SYNDROME

LYRA, Joao Cesar; MASCARETTI, Renata Suman; PRECIOSO, Alexander Roberto; HADDAD, Luciana Branco; MAUAD, Thais; VAZ, Flavio A. Costa; REBELLO, Celso Moura
Fonte: TAYLOR & FRANCIS INC Publicador: TAYLOR & FRANCIS INC
Tipo: Artigo de Revista Científica
ENG
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Meconium (MEC) is a potent inactivator of pulmonary surfactant. The authors studied the effects of polyethylene glycol addition to the exogenous surfactant over the lung mechanics and volumes. Human meconium was administrated to newborn rabbits. Animals were ventilated for 20 minutes and dynamic compliance, ventilatory pressure, and tidal volume were recorded. Animals were randomized into 3 study groups: MEC group (without surfactant therapy); S100 group (100 mg/kg surfactant); and PEG group (100 mg/kg porcine surfactant plus 5% PEG). After ventilation, a pulmonary pressure-volume curve was built. Histological analysis was carried out to calculate the mean alveolar size (Lm) and the distortion index (DI). Both groups treated with surfactant showed higher values of dynamic pulmonary compliance and lower ventilatory pressure, compared with the MEC group (P .05). S100 group had a larger maximum lung volume, V30, compared with the MEC group (P .05). Lm and DI values were smaller in the groups treated with surfactant than in the MEC group (P .05). No differences were observed between the S100 and PEG groups. Animals treated with surfactant showed significant improvement in pulmonary function as compared to nontreated animals. PEG added to exogenous surfactant did not improve lung mechanics or volumes.

Interaction of giant extracellular Glossoscolex paulistus hemoglobin (HbGp) with zwitterionic surfactant N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (HPS): Effects of oligomeric dissociation

MOREIRA, Leonardo M.; SANTIAGO, Patricia S.; ALMEIDA, Erika V. de; TABAK, Marcel
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
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The present work focuses on the interaction between the zwitterionic surfactant N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (HPS) and the giant extracellular hemoglobin of Glossoscolex paulistus (HbGp). Electronic optical absorption, fluorescence emission and circular dichroism spectroscopy techniques, together with Gel-filtration chromatography, were used in order to evaluate the oligomeric dissociation as well as the autoxidation of HbGp as a function of the interaction with HPS. A peculiar behavior was observed for the HPS-HbGp interaction: a complex ferric species formation equilibrium was promoted, as a consequence of the autoxidation and oligomeric dissociation processes. At pH 7.0, HPS is more effective up to 1 mM while at pH 9.0 the surfactant effect is more intense above 1 mM. Furthermore, the interaction of HPS with HbGp was clearly less intense than the interaction of this hemoglobin with cationic (CTAC) and anionic (SDS) surfactants. Probably, this lower interaction with HPS is due to two factors: (i) the lower electrostatic attraction between the HPS surfactant and the protein surface ionic sites when compared to the electrostatic interaction between HbGp and cationic and anionic surfactants, and (ii) the low cmc of HPS...

Avaliação da proteína A do surfactante na síndrome hepatopulmonar em ratos; Evaluation of surfactant protein A in hepatopulmonary syndrome in rats

Nacif, Lucas Souto
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 13/03/2013 PT
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INTRODUÇÃO: A síndrome hepatopulmonar (SHP) é formada por uma tríade: doença hepática, dilatação vascular intrapulmonar e alteração dos gases no sangue. Sua patogenia não está bem definida, mas especula-se que a combinação de fatores, tais como o desequilíbrio da resposta de receptores da endotelina, a remodelação microvascular pulmonar, a predisposição genética e a translocação de bactérias sejam os desencadeadores das alterações que levarão ao desenvolvimento da síndrome. O pulmão é o local principal de produção do surfactante (células alveolares epiteliais do tipo II) e desempenha um papel importante na lesão e doenças inflamatórias pulmonares. Até o momento não há relatos de avaliação do surfactante na cirrose ou na SHP. OBJETIVO: Avaliar a concentração da proteína A do surfactante na síndrome hepatopulmonar induzida em ratos. MÉTODO: Três grupos de ratos foram divididos em controle, Sham e grupo experimental de SHP. Grupo controle: somente coleta dos exames; grupo Sham: realizada a cirurgia simulada; e o grupo do modelo experimental: indução de cirrose biliar secundária através da ligadura da via biliar principal. Foi realizado a avaliação da proteína A do surfactante no homogenato pulmonar e sérico através do método imunoenzimático ELISA indireto. RESULTADOS: Observou-se depois de 28 dias a evidência de cirrose em todos os ratos operados e a apresentação de SHP em 85% dos ratos. No homogenato do pulmão no grupo LVBP e Sham...

Avaliação da função de um novo surfactante de origem porcina obtido da extração orgânica acoplada à adsorção em derivado de celulose; In vivo function of a new porcine pulmonary surfactant obtained by organic extraction coupled with adsorption on a cellulose derivative

Chia, Chang Yin
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 25/08/2004 PT
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INTRODUÇÃO: O tratamento das doenças decorrentes das deficiências quantitativa ou qualitativa do surfactante pulmonar consiste na reposição exógena, porém, esta terapêutica é de alto custo devido, basicamente, à metodologia sofisticada de produção do surfactante e à necessidade de importação. Com o propósito de reduzir os custos deste tratamento, o Instituto Butantan, em São Paulo, Brasil, desenvolveu uma nova tecnologia de produção, que demanda menor custo, através da extração orgânica de macerado de pulmão de suínos acoplada à adsorção em um derivado de celulose (DEAE-celulose). MÉTODOS: Com o objetivo de testar a eficácia deste novo produto, 74 coelhos prematuros de 27 dias de gestação foram randomizados em três grupos de estudo, de acordo com o tipo de tratamento realizado: Grupo Controle (n = 28, sem tratamento), Grupo Butantan (n = 22, Surfactante Butantan 50 mg/kg) e Grupo Survanta (n = 24, Survanta® 50 mg/kg). Os animais foram submetidos à ventilação mecânica com freqüência respiratória de 60 ciclos/ minuto, pressão expiratória positiva final de zero, tempo inspiratório de 0,5 segundo e fração inspirada de oxigênio de 21%, durante 20 minutos. O volume-corrente foi ajustado manualmente em 8 ml/kg durante o período da ventilação e a pressão ventilatória (pressão inspiratória - pressão expiratória final positiva) atingida foi registrada através de um pletismógrafo a cada 5 minutos. A complacência dinâmica foi determinada pela relação entre o volume-corrente e a pressão ventilatória. Ao final da ventilação...

POLYETHYLENE GLYCOL ADDITION DOES NOT IMPROVE EXOGENOUS SURFACTANT FUNCTION IN AN EXPERIMENTAL MODEL of MECONIUM ASPIRATION SYNDROME

Lyra, Joao Cesar; Mascaretti, Renata Suman; Precioso, Alexander Roberto; Haddad, Luciana Branco; Mauad, Thais; Vaz, Flavio A. Costa; Rebello, Celso Moura
Fonte: Taylor & Francis Inc Publicador: Taylor & Francis Inc
Tipo: Artigo de Revista Científica Formato: 76-88
ENG
Relevância na Pesquisa
37.05477%
Meconium (MEC) is a potent inactivator of pulmonary surfactant. The authors studied the effects of polyethylene glycol addition to the exogenous surfactant over the lung mechanics and volumes. Human meconium was administrated to newborn rabbits. Animals were ventilated for 20 minutes and dynamic compliance, ventilatory pressure, and tidal volume were recorded. Animals were randomized into 3 study groups: MEC group (without surfactant therapy); S100 group (100 mg/kg surfactant); and PEG group (100 mg/kg porcine surfactant plus 5% PEG). After ventilation, a pulmonary pressure-volume curve was built. Histological analysis was carried out to calculate the mean alveolar size (Lm) and the distortion index (DI). Both groups treated with surfactant showed higher values of dynamic pulmonary compliance and lower ventilatory pressure, compared with the MEC group (P .05). S100 group had a larger maximum lung volume, V30, compared with the MEC group (P .05). Lm and DI values were smaller in the groups treated with surfactant than in the MEC group (P .05). No differences were observed between the S100 and PEG groups. Animals treated with surfactant showed significant improvement in pulmonary function as compared to nontreated animals. PEG added to exogenous surfactant did not improve lung mechanics or volumes.

Interaction of anionic azo dye and TTAB: cationic surfactant

Ghoreishi,Sayed Mehdi; Behpour,Mohsen; Shabani-Nooshabadi,Mehdi
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2009 EN
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Interaction between three anionic azo dyes, C.I. Acid Red 14 (AR14), C.I. Acid Red 1 (AR1), C.I. Acid Orange 7 (AO7) and a cationic surfactant tetradecyltrimethylammonium bromide (TTAB) has been investigated using surfactant selective electrode technique. The TTAB selective electrode was constructed and used to determine the concentration of TTAB monomers and also surfactant ions bounded to dyes by electromotive force data. The dye-surfactant complex formation constant, K1, and the standard free energy change, ΔG1º, could be obtained from the experimental data. The results indicate that in the TTAB/AO7 system, where the more hydrophobic dye AO7 is used, the dye-surfactant interactions are stronger than in other systems. The results also indicate that both the electrostatic attractive and the hydrophobic interactions are very important for the formation of the complex between the oppositely-charged dyes and the surfactant. Maximum binding capacities of the dyes and also the degree of binding of the surfactant to the dyes were calculated from the experimental data.

Analysis of the immunogenicity and stability of a porcine pulmonary surfactant preparation administered in rabbits

Precioso,Alexander R.; Sakae,Paula P.O; Mascaretti,Renata S.; Kubrusly,Flávia S.; Gebara,Vera C. B. Cainelli; Iourtov,Dmitri; Rebello,Celso M.; Vaz,Flávio A. C.; Raw,Isaías
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2006 EN
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PURPOSE: To study the immunogenicity and the stability of the porcine pulmonary surfactant preparation produced by the Instituto Butantan. METHOD: Immunogenicity assay: Sixteen New-Zealand-White rabbits (1000 g body weight) were divided into 4 study groups. Each group was assigned to receive either a) Butantan surfactant, b) Survanta® (Abbott Laboratories), c) Curosurf® (Farmalab Chiesi), or d) no surfactant. The surfactants were administered intratracheally, and the animals were collected immediately before and 60 and 180 days after surfactant administration. Sera were assayed for the presence of antisurfactant antibodies by enzyme-linked immunosorbent assay (ELISA). Stability assay: The Butantan surfactant used in this assay had been stored for one year in the refrigerator (4 to 8ºC) and its stability was evaluated in distinct assay conditions using a premature rabbit model. RESULTS: Immunogenicity assay: None of the surfactants analyzed triggered antibody immune responses against their components in any of the animals. Stability assay: The results of this study demonstrate that Butantan surfactant was as effective as Curosurf when both were submitted to the adverse circumstance of short- and long-term storage at room temperature. A similar level of efficacy for the Butantan surfactant...

The importance of surfactant on the development of neonatal pulmonary diseases

Lyra,Priscila Pinheiro Ribeiro; Diniz,Edna Maria de Albuquerque
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2007 EN
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Pulmonary surfactant is a substance composed of a lipoprotein complex that is essential to pulmonary function. Pulmonary surfactant proteins play an important role in the structure, function, and metabolism of surfactant; 4 specific surfactant proteins have been identified: surfactant proteins-A, surfactant proteins-B, surfactant proteins-C, and surfactant proteins-D. Clinical, epidemiological, and biochemical evidence suggests that the etiology of respiratory distress syndrome is multifactorial with a significant genetic component. There are reports about polymorphisms and mutations on the surfactant protein genes, especially surfactant proteins-B, that may be associated with respiratory distress syndrome, acute respiratory distress syndrome, and congenital alveolar proteinosis. Individual differences regarding respiratory distress syndrome and acute respiratory distress syndrome as well as patient response to therapy might reflect phenotypic diversity due to genetic variation, in part. The study of the differences between the allelic variants of the surfactant protein genes can contribute to the understanding of individual susceptibility to the development of several pulmonary diseases. The identification of the polymorphisms and mutations that are indeed important for the pathogenesis of the diseases related to surfactant protein dysfunction...

Modelagem matemática e simulação computacional de escoamentos bifásicos com a presença de surfactante insolúvel; Mathematical modeling and computational simulation of two-phase ows with insoluble surfactant

Miranda, Flavia Cavalcanti
Fonte: Universidade Federal de Uberlândia Publicador: Universidade Federal de Uberlândia
Tipo: Dissertação
POR
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Quando se trata de escoamentos bifásicos, torna-se inevitável falar de surfactantes. Surfactantes são agentes ativos de superfície que podem estar presentes em sistemas, tanto na forma de impurezas quanto na forma de substâncias químicas adicionadas propositalmente _a misturas para controlar efeitos físicos interfaciais. Os surfactantes são amplamente usados em numerosas aplica _c~oes de engenharia, como por exemplo, eles são usados na produção de emulsões, ou para manipular bolhas e gotas em microcanais, para estabilizar gotas suspensas em um meio imiscível, também usados no processo de purificação de _água, etc. As funções principais do surfactante são diminuir a tensão superficial e prevenir a coalescência. A presença destes agentes ativos pode afetar criticamente a dinâmica interfacial dos escoamentos bifásicos. Surfactantes aderidos _a interface resultam em uma diminuição não uniforme de tensão superficial, isso torna a força de capilaridade não linear a introduz a força de Marangoni. Utilizando o método Front-Tracking e malhas adaptativas refinadas localmente, o presente trabalho tem como objetivo estudar o efeito de surfactantes insolúveis em escoamentos interfaciais bidimensionais. O surfactante dito insolúvel _e aquele que se mantém na interface e não há uxo de massa de surfactante entre a interface e o ruido ambiente. Portanto...

Combined and Independent Action of Proteins SP-B and SP-C in the Surface Behavior and Mechanical Stability of Pulmonary Surfactant Films; Biophysical Journal

Schurch, David; Ospina Ramírez, Olga Lucía; Cruz, Antonio; Pérez Gil, Jesús
Fonte: Pontifícia Universidade Javeriana Publicador: Pontifícia Universidade Javeriana
Formato: 3290–3299
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99; The hydrophobic proteins SP-B and SP-C are essential for pulmonary surfactant function, even though they are a relatively minor component (<2% of surfactant dry mass). Despite countless studies, their specific differential action and their possible concerted role to optimize the surface properties of surfactant films have not been completely elucidated. Under conditions kept as physiologically relevant as possible, we tested the surface activity and mechanical stability of several surfactant films of varying protein composition in vitro using a captive bubble surfactometer and a novel (to our knowledge) stability test. We found that in the naturally derived surfactant lipid mixtures, surfactant protein SP-B promoted film formation and reextension to lower surface tensions than SP-C, and in particular played a vital role in sustaining film stability at the most compressed states, whereas SP-C produced no stabilization. Preparations containing both proteins together revealed a slight combined effect in enhancing film formation. These results provide a qualitative and quantitative framework for the development of future synthetic therapeutic surfactants, and illustrate the crucial need to include SP-B or an efficient SP-B analog for optimal function.; The hydrophobic proteins SP-B and SP-C are essential for pulmonary surfactant function...

Palmitoylation of Pulmonary Surfactant Protein SP-C Is Critical for Its Functional Cooperation with SP-B to Sustain Compression/Expansion Dynamics in Cholesterol-Containing Surfactant Films; Biophysical Journal Volume 99 November 2010

Baumbgart, Florian; Ospina, Olga L.; Mingarro, Ismael; Rodríguez-Crespo, Ignacio; Pérez-Gil, Jesus
Fonte: Pontifícia Universidade Javeriana Publicador: Pontifícia Universidade Javeriana
Formato: 3234–3243
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Volume 99; Recent data suggest that a functional cooperation between surfactant proteins SP-B and SP-C may be required to sustain a proper compression-expansion dynamics in the presence of physiological proportions of cholesterol. SP-C is a dually palmitoylated polypeptide of 4.2 kDa, but the role of acylation in SP-C activity is not completely understood. In this work we have compared the behavior of native palmitoylated SP-C and recombinant nonpalmitoylated versions of SP-C produced in bacteria to get a detailed insight into the importance of the palmitic chains to optimize interfacial performance of cholesterol-containing surfactant films. We found that palmitoylation of SP-C is not essential for the protein to promote rapid interfacial adsorption of phospholipids to equilibrium surface tensions (~22 mN/m), in the presence or absence of cholesterol. However, palmitoylation of SP-C is critical for cholesterol-containing films to reach surface tensions%1 mN/m at the highest compression rates assessed in a captive bubble surfactometer, in the presence of SP-B. Interestingly, the ability of SP-C to facilitate reinsertion of phospholipids during expansion was not impaired to the same extent in the absence of palmitoylation, suggesting the existence of palmitoylation- dependent and -independent functions of the protein. We conclude that palmitoylation is key for the functional cooperation of SP-C with SP-B that enables cholesterol-containing surfactant films to reach very low tensions under compression...

Adaptation to low body temperature influences pulmonary surfactant composition thereby increasing fluidity while maintaining appropriately ordered membrane structure and surface activity; Biochimica et Biophysica Acta

Suri, Lakshmi N.M.; McCaig, Lynda; Picardi, Maria V.; Ospina, Olga L.; Veldhuizen, Ruud A.W.; Staples, James F.; Possmayer, Fred; Yao, Li-Juan; Perez-Gil, Jesus; Orgeig, Sandra
Fonte: Pontifícia Universidade Javeriana Publicador: Pontifícia Universidade Javeriana
Formato: 1581–1589
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1818; The interfacial surface tension of the lung is regulated by phospholipid-rich pulmonary surfactant films. Small changes in temperature affect surfactant structure and function in vitro. We compared the compositional, thermodynamic and functional properties of surfactant from hibernating and summer-active 13-lined ground squirrels (Ictidomys tridecemlineatus) with porcine surfactant to understand structure-function relationships in surfactant membranes and films. Hibernating squirrels had more surfactant large aggregates with more fluid monounsaturated molecular species than summer-active animals. The latter had more unsaturated species than porcine surfactant. Cold-adapted surfactant membranes displayed gel-to-fluid transitions at lower phase transition temperatures with reduced enthalpy. Both hibernating and summer-active squirrel surfactants exhibited lower enthalpy than porcine surfactant. LAURDAN fluorescence and DPH anisotropy revealed that surfactant bilayers from both groups of squirrels possessed similar ordered phase characteristics at low temperatures. While ground squirrel surfactants functioned well during dynamic cycling at 3, 25, and 37 °C, porcine surfactant demonstrated poorer activity at 3 °C but was superior at 37 °C. Consequently the surfactant composition of ground squirrels confers a greater thermal flexibility relative to homeothermic mammals...

Conservation of surfactant protein a: evidence for a single origin for vertebrate pulmonary surfactant

Sullivan, Lucy C.; Daniels, Christopher Brian; Phillips, Ian D.; Orgeig, Sandra; Whitsett, Jeffrey A.
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Artigo de Revista Científica
Publicado em //1998 EN
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Surface tension is reduced at the air–liquid interface in the lung by a mixture of lipids and proteins termed pulmonary surfactant. This study is the first to provide evidence for the presence of a surfactant-specific protein (Surfactant Protein A—SP-A) in the gas-holding structures of representatives of all the major vertebrate groups. Western blot analysis demonstrated cross-reactivity between an antihuman SP-A antibody and material lavaged from lungs or swimbladders of members from all vertebrate groups. Immunocytochemistry localized this SP-A–like protein to the air spaces of lungs from the actinopterygiian fish and lungfish. Northern blot analysis indicated that regions of the mouse SP-A cDNA sequence are complementary to lung mRNA from all species examined. The presence of an SP-A–like protein and SP-A mRNA in members of all the major vertebrate groups implies that the surfactant system had a single evolutionary origin in the vertebrates. Moreover, the evolution of the surfactant system must have been a prerequisite for the evolution of airbreathing. The presence of SP-A in the goldfish swimbladder demonstrates a role for the surfactant system in an organ that is no longer used for airbreathing.; Lucy C. Sullivan, Christopher B. Daniels...

The evolution of a physiological system: the pulmonary surfactant system in diving mammals.

Miller, Natalie J.
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado Formato: 636225 bytes; 949420 bytes; 2731599 bytes; 190928 bytes; application/pdf; application/pdf; application/pdf; application/pdf
Publicado em //2005 EN
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Pulmonary surfactant is a complex mixture of lipids and proteins that lowers surface tension, increases lung compliance, and prevents the adhesion of respiratory surfaces and pulmonary oedema. Pressure can have an enormous impact on respiratory function, by mechanically compressing tissues, increasing gas tension resulting in increased gas absorption and by increasing dissolved gas tensions during diving, resulting in the formation of bubbles in the blood and tissues. The lungs of diving mammals have a huge range of morphological adaptations to enable them to endure the extremely high pressures associated with deep diving. Here, I hypothesise that surfactant will also be modified, to complement the morphological changes and enable more efficient lung function during diving. Molecular adaptations to diving were examined in surfactant protein C (SP-C) using phylogenetic analyses. The composition and function of pulmonary surfactant from several species of diving mammals was examined using biochemical assays, mass spectrometry and captive bubble surfactometry. The development of surfactant in one species of diving mammal (California sea lion), and the control of surfactant secretion using chemical and mechanical stimuli were also determined. Diving mammals showed modifications to SP-C...

Rekombinanter humaner Keratinozytenwachstumsfaktor als Alternative zu Glukokortikoiden: Spezifische Effekte auf Surfactantstatus und Leberphospholipide in neugeborenen Ratten; Recombinant human keratinocyte growth factor as an alternative to glucocorticoids: Specific effects on surfactant state and phospholipid contribution in liver and lung of newborn rats

Ohler, Florian Michael
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
DE_DE
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Die Entwicklung eines Respiratory Distress Syndroms bei Frühgeborenen mit funktioneller Lungenunreife gehört zu den wichtigsten behandlungsbedürftigen Erkrankungen in der Neonatologie. Wesentlicher pathogenetischer Aspekt dieser Erkrankung ist der Surfactant-Mangel, der in der Folge durch erhöhte Oberflächenspannung zur Atelektasenbildung und respiratorischer Insuffizienz führt. Zwar konnten in den vergangenen Jahrzehnten immense Fortschritte in der Therapie und eine deutliche Reduktion des Mortalitätsrisikos erreicht werden, präventiv eingesetzt wird derzeit nur die ante- bzw. perinatale Gabe von Cortikosteroiden mit vielen systemischen Nebenwirkungen. In dieser Arbeit wurde im tierexperimentellen Ansatz an der sich entwickelnden Rattenlunge getestet, inwiefern sich rekombinanter humaner Keratinozyten-Wachstumsfaktor im Vergleich zur Betamethason-Gabe, der derzeitigen Standardtherapie der „Lungenreifeinduktion“, als therapeutische Alternative anbietet. Hierzu wurden neugeborenen Sprague-Dawley-Ratten zu unterschiedlichen Zeitpunkten postnatal (nach 1, 5, 13 und 19 Tagen) über 2 Tage gewichtsadaptierte Mengen an rhKGF, Betamethason oder eine Kombination aus beiden appliziert und die Auswirkungen der Substanzgabe auf die Phospholipidzusammensetzung in Lunge...

Transport of Surfactant and Foam in Porous Media for Enhanced Oil Recovery Processes

Ma, Kun
Fonte: Universidade Rice Publicador: Universidade Rice
ENG
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The use of foam-forming surfactants offers promise to improve sweep efficiency and mobility control for enhanced oil recovery (EOR). This thesis provides an in depth understanding of transport of surfactant and foam through porous media using a combination of laboratory experiments and numerical simulations. In particular, there are several issues in foam EOR processes that are examined. These include screening of surfactant adsorption onto representative rock surfaces, modeling of foam flow through porous media, and studying the effects of surface wettability and porous media heterogeneity. Surfactant adsorption onto rock surfaces is a main cause of foam chromatographic retardation as well as increased process cost. Successful foam application requires low surfactant adsorption on reservoir rock. The focus of this thesis is natural carbonate rock surfaces, such as dolomite. Surfactant adsorption was found to be highly dependent on electrostatic interactions between surfactants and rock surface. For example, the nonionic surfactant Tergitol 15-S-30 exhibits low adsorption on dolomite under alkaline conditions. In contrast, high adsorption of cationic surfactants was observed on some natural carbonate surfaces. XPS analysis reveals silicon and aluminum impurities exist in natural carbonates...

Praxis des Einsatzes von prä- und postnatalen Steroiden und Surfactant an geburtshilflichen bzw. neonatologischen Abteilungen in Baden-Württemberg; Practice of the pre- and postnatal use of steroids and surfactant at obstetric resp. neonatological departments in Baden-Württemberg

Beck, Florian
Fonte: Universität Tübingen Publicador: Universität Tübingen
Tipo: Dissertation; info:eu-repo/semantics/doctoralThesis
DE_DE
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Fragestellung: Klinikinterne Strategien für den pränatalen Einsatz von Steroiden (ANCS) und den postnatalen Einsatz von Surfactant und Steroiden (PCS) in Baden-Württemberg wurden evaluiert und mit den bestehenden Empfehlungen verglichen. Methode: Standardisierte Fragebogen wurde 1999 und 2000 an 131 geburtshilfliche Einrichtungen und 30 Kinderkliniken mit NICU in Baden-Württemberg versandt. Ergebnisse: ANCS: 59,0 haben ein Protokoll zum Gebrauch von ANCS. Beginn der Behandlung im Median 24 Wochen, Ende im Median 34 Wo. Gestationsalter. Im Median wird mit 8mg/24h behandelt. 59,0 behandeln 48 Stunden (Streuung 24h-8d). Keine wesentlichen Änderungen bei Mehrlingen. 91,6 geben mehrere Zyklen ANCS. Surfactant: Alle 30 Kliniken geben Surfactant. 53,3 haben ein Protokoll zum Gebrauch. 80,0 geben Alveofact, 40,0 Curosurf. Zeitpunkt der Gabe bezogen auf das Gestationsalter (24–27Wo/28–31Wo/>31Wo): Prophylaxe 7/0/3, frühe Gabe 90/43/27, Rescue 20/60/70 (Doppelnennung mögl.). Beatmungsformen: 67,8 IPPV, 15,3 SIMV, 11,8 HFV. PCS: 93,3 verwenden PCS. 53,3 haben ein Protokoll für den Gebrauch. 23,3 geben Steroide postnatal zur Prävention, 90,0 zur Therapie der CLD. 90,0 verwenden Dexamethason, 16,7 inhalative Steroide, 3,3 Prednisolon. 33...

The influence of surfactant mixing ratio on nano-emulsion formation by the pit method

Izquierdo, P.; Feng, Jin; Esquena, Jordi; Tadros, Tharwat F.; Dederen, Joseph C.; García, María José; Azemar Sazatornil, Nuria; Solans, Conxita
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 22195 bytes; application/pdf
ENG
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7 pages, 6 figures, 2 tables.-- PMID: 15797437 [PubMed].-- Available online Dec 23, 2004.; The formation of O/W nano-emulsions by the PIT emulsification method in water/mixed nonionic surfactant/oil systems has been studied. The hydrophilic–lipophilic properties of the surfactant were varied by mixing polyoxyethylene 4-lauryl ether (View the MathML source) and polyoxyethylene 6-lauryl ether (View the MathML source). Emulsification was performed in samples with constant oil concentration (20 wt%) by fast cooling from the corresponding HLB temperature to 25 °C. Nano-emulsions with droplet radius 60–70 nm and 25–30 nm were obtained at total surfactant concentrations of 4 and 8 wt%, respectively. Moreover, droplet size remained practically unchanged, independent of the surfactant mixing ratio, XC12E6. At 4 wt% surfactant concentration, the polydispersity and instability of nano-emulsions increased with the increase in XC12E6. However, at 8 wt% surfactant concentration, nano-emulsions with low polydispersity and high stability were obtained in a wide range of surfactant mixing ratios. Phase behavior studies showed that at 4 wt% surfactant concentration, three-liquid phases (W + D + O) coexist at the starting emulsification temperature. Furthermore...

Síndrome da angustia respiratória aguda e proteinose alveolar congênita; The importance of surfactant on the development of neonatal pulmonary diseases

Lyra, Priscila Pinheiro Ribeiro; Diniz, Edna Maria de Albuquerque
Fonte: Universidade de São Paulo. Faculdade de Medicina Publicador: Universidade de São Paulo. Faculdade de Medicina
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; Formato: application/pdf
Publicado em 01/01/2007 ENG
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O surfactante pulmonar é uma substância composta por um complexo lipoprotéico essencial para a função pulmonar normal. As proteínas do surfactante têm importante papel na estrutura, função e metabolismo do surfactante. São descritas quatro proteínas específicas denominadas surfactante pulmonar-A, surfactante pulmonar-B, surfactante pulmonar-C e surfactante pulmonar-D. Evidências clínicas, epidemiológicas e bioquímicas sugerem que a etiologia da síndrome do desconforto respiratório é multifatorial com um componente genético significativo. Existem na literatura algumas descrições sobre a presença de polimorfismos e mutações em genes dos componentes do surfactante, particularmente no gene da surfactante pulmonar-B, os quais parecem estar associados à síndrome do desconforto respiratório, síndrome da angustia respiratória aguda e proteinose alveolar congênita. Diferenças individuais relacionadas à síndrome do desconforto respiratórioe síndrome da angustia respiratória aguda e à resposta dos pacientes ao tratamento podem refletir diversidade fenotípica, devido, parcialmente, à variação genética. O estudo das diferenças entre as variantes alélicas dos genes das proteínas do surfactante pode ajudar na compreensão das variabilidades individuais na susceptibilidade ao desenvolvimento de várias doenças pulmonares. A determinação de quais polimorfismos e mutações são...

Análise da imunogenicidade e da estabilidade do surfactante pulmonar de origem porcina administrado em coelhos; Analysis of the immunogenicity and stability of a porcine pulmonary surfactant preparation administered in rabbits

Precioso, Alexander R.; Sakae, Paula P.O; Mascaretti, Renata S.; Kubrusly, Flávia S.; Gebara, Vera C. B. Cainelli; Iourtov, Dmitri; Rebello, Celso M.; Vaz, Flávio A. C.; Raw, Isaías
Fonte: Universidade de São Paulo. Faculdade de Medicina Publicador: Universidade de São Paulo. Faculdade de Medicina
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; Formato: application/pdf
Publicado em 01/04/2006 ENG
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OBJETIVO: Estudar a imunogenicidade e a estabilidade do surfactante de origem porcina produzido pelo Instituto Butantan. MÉTODO: Experimento imunogenicidade: 16 coelhos da raça New-Zealand-White (Peso de 1000g) foram divididos em grupos de 4 animais. Cada grupo foi designado para receber: a) Surfactante do Butantan, b) Survanta® (Abbott Laboratories), c) Curosurf (Farmalab Chiesi) e d) nenhum tratamento com surfactante. Os surfactantes foram administrados via intratraqueal e o sangue dos animais foi coletado antes, 60 e 180 dias após a administração do surfactante. O soro obtido foi analisado quanto a presença de anticorpos anti-surfactante pelo método ELISA (enzyme-linked immunosorbent assay). Experimento estabilidade: O surfactante do Butantan usado neste experimento tinha sido armazenado por um ano em refrigerador (4 a 8°C) e sua estabilidade foi analisada em condições distintas de experimentação, usando o modelo de coelho prematuro. RESULTADOS: Experimento imunogenicidade: Nenhum dos surfactantes analisados determinou a produção de anticorpos contra seus constituintes. Experimento estabilidade: Os resultados deste estudo demonstraram que o surfactante do Instituto Butantan mostrou eficácia semelhante a do Curosurf após ter sido submetido à condições adversas ao longo do tempo. A eficácia foi demonstrada através da complacência pulmonar dinâmica...