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Local delivery of EGF-liposome mediated bone modeling in orthodontic tooth movement by increasing RANKL expression

ALVES, Jose B.; FERREIRA, Cynthia L.; MARTINS, Aline F.; SILVA, Gerluza A. B.; ALVES, Guilherme D.; PAULINO, Tony P.; CIANCAGLINI, Pietro; THEDEI JR., Geraldo; NAPIMOGA, Marcelo H.
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.98853%
Aims: It has long been demonstrated that epidermal growth factor (EGF) has catabolic effects oil bone. Thus. we examined the role of EGF in regulating mechanically induced bone modeling in a rat model of orthodontic tooth movement. Main methods: The maxillary first molars of rats were moved mesially using an orthodontic appliance attached to the maxillary incisor teeth. Rats were randomly divided into 4 groups: (G1) administration of PBS (Phosphate buffer saline Solution (n = 24); (G2) administration of empty liposomes (it = 24): (Q) administration 20 rig of EGF Solution (n = 24): and (G4) 20 ng of EGF-liposomes Solution (it = 24). Each Solution was injected in the mucosa of the left first molar adjacent to the appliance. At days 5, 10, 14 and 2 1 after drug administration. 6 animals of each group were sacrificed. Histomorphometric analysis was used to quantify osteoclasts (Tartrate-resistant acid phosphatase (TRAP) + cells) and tooth movement. Using immunohistochemistry assay we evaluated the RANKL (receptor activator of nuclear factor kappa B ligand) and epidermal growth factor receptor (EGFR) expression. Key findings: The EGF-liposome administration showed an increased tooth movement and osteoclast numbers compared to controls (p<0.05). This was correlated with intense RANKL expression. Both osteoblasts and osteoclasts expressed EGFR. Significance: Local delivery of EGF-liposome stimulates...

Design of a Modern Liposome and Bee Venom Formulation for the Traditional VIT-Venom Immunotherapy

SILVA, Tatiana C.; MOURA, Sergio De Paula; RAMOS, Henrique R.; ARAUJO, Pedro S. De; COSTA, Maria H. Bueno Da
Fonte: TAYLOR & FRANCIS INC Publicador: TAYLOR & FRANCIS INC
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.846492%
Traditional venom immunotherapy uses injections of whole bee venom in buffer or adsorbed in Al (OH)(3) in an expensive, time-consuming way. New strategies to improve the safety and efficacy of this treatment with a reduction of injections would, therefore, be of general interest. It would improve patient compliance and provide socio-economic benefits. Liposomes have a long tradition in drug delivery because they increase the therapeutic index and avoid drug degradation and secondary effects. However, bee venom melittin (Mel) and phospholipase (PLA(2)) destroy the phospholipid membranes. Our central idea was to inhibit the PLA(2) and Mel activities through histidine alkylation and or tryptophan oxidation (with pbb, para-bromo-phenacyl bromide, and/or NBSN-bromosuccinimide, respectively) to make their encapsulations possible within stabilized liposomes. We strongly believe that this formulation will be nontoxic but immunogenic. In this paper, we present the whole bee venom conformation characterization during and after chemical modification and after interaction with liposome by ultraviolet, circular dichroism, and fluorescence spectroscopies. The PLA(2) and Mel activities were, measured indirectly by changes in turbidity at 400(nm)...

Effectiveness, against tuberculosis, of pseudo-ternary complexes: Peptide-DNA-cationic liposome

Rosada, Rogerio Silva; Silva, Cello Lopes; Andrade Santana, Maria Helena; Nakaie, Clovis Ryuichi; de la Torre, Lucimara Gaziola
Fonte: ACADEMIC PRESS INC ELSEVIER SCIENCE; SAN DIEGO Publicador: ACADEMIC PRESS INC ELSEVIER SCIENCE; SAN DIEGO
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.846492%
We report the effects of a synthetic peptide designed to act as a nuclear localization signal on the treatment of tuberculosis. The peptide contains 21 amino acid residues with the following specific domains: nuclear localization signal from SV 40T, cationic shuttle sequence, and cysteamide group at the C-terminus. The peptide was complexed with the plasmid DNAhsp65 and incorporated into cationic liposomes, forming a pseudo-ternary complex. The same cationic liposomes, composed of egg chicken L-alpha-phosphatidylcholine, 1,2-dioleoyl-3-trimethylammonium-propane, and 1,2-dioleoyl-3-trimethylammonium-propane (2:1:1 M), were previously evaluated as a gene carrier for tuberculosis immunization protocols with DNAhsp65. The pseudo-ternary complex presented a controlled size (250 nm), spherical-like shape, and various lamellae in liposomes as evaluated by transmission electron microscopy. An assay of fluorescence probe accessibility confirmed insertion of the peptide/DNA into the liposome structure. Peptide addition conferred no cytotoxicity in vitro, and similar therapeutic effects against tuberculosis were seen with four times less DNA compared with naked DNA treatment. Taken together, the results indicate that the pseudo-ternary complex is a promising gene vaccine for tuberculosis treatment. This work contributes to the development of multifunctional nanostructures in the search for strategies for in vivo DNA delivery. (C) 2011 Elsevier Inc. All rights reserved.; Fundacao de Amparo Pesquisa do Estado de Sao Paulo (FAPESP); Fundacao de Amparo Pesquisa do Estado de Sao Paulo (FAPESP)

Sistemas carreadores de proteínas antigênicas da membrana de Pasteurella multocida para a prevenção da pasteurelose; Carrier liposome systems of Pasteurella multocida membrane antigenic proteins for the prevention of pasteurellose

Daghastanli, Katia Regina Perez
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 07/12/2004 PT
Relevância na Pesquisa
36.846492%
A pasteurelose é uma das doenças mais comuns do trato respiratório do coelho em criações comerciais e/ou em biotérios de animais destinados à pesquisa biomédica. A bactéria Pasteurella multocida é o patógeno responsável por uma série de manifestações clínicas em coelhos, incluindo rinite crônica, otite média, pneumonia, infecções no trato genital, formação de abscessos pulmonares e cutâneos, conjuntivite e septicemia hemorrágica. Porém, entre 50 e 70 % dos animais podem incubar o organismo de forma assintomática. Os fatores predisponentes para o desencadeamento dos sinais clínicos incluem acúmulo de amônia no ar (má ventilação), prenhez, aparecimento de doenças concomitantes, distúrbios no ambiente de criação ou na manipulação experimental. A doença está presente no Brasil, ocorrendo surtos com relativa freqüência, no entanto, o diagnóstico é feito com base nos sinais clínicos e necropsia. Dessa forma é difícil precisar a extensão dos prejuízos causados pela pasteurelose à cunicultura. Vacinas comerciais específicas contra a pasteurelose em coelhos não estão disponíveis no mercado. A prevenção, ainda que apresente resultados duvidosos, é realizada utilizando-se antibióticos dissolvidos na água...

Pharmacokinetic Profile of Liposome-Encapsulated Ropivacaine after Maxillary Infiltration Anaesthesia

Franz-Montan, Michelle; Bergamaschi, Cristiane de Cassia; de Paula, Eneida; Groppo, Francisco C.; Ranali, Jose; Fraceto, Leonardo Fernandes; Volpato, Maria C.
Fonte: Soc Brasileira Quimica Publicador: Soc Brasileira Quimica
Tipo: Artigo de Revista Científica Formato: 1945-1951
ENG
Relevância na Pesquisa
36.846492%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 06/00121-9; Processo FAPESP: 06/53255-2; The aim of this study was to determine the pharmacokinetic parameters of liposomal ropivacaine after dental anesthesia in 14 healthy volunteers. In this randomized, double-blind and crossover study, the volunteers received maxillary infiltration of liposome-encapsulated 0.5% ropivacaine and, 0.5% ropivacaine with 1:200,000 epinephrine in two different sessions. Blood samples were collected before and after (from 15 to 1440 min) the administration of either ropivacaine formulation. HPLC with UV detection was used to quantify plasma ropivacaine concentrations. The pharmacokinetic parameters AUC(0-24) (area under the plasma concentration x time curve from baseline to 24 h), AUC(0-infinity) (area under the plasma concentration-time curve from baseline to infinity), C-max (maximum drug concentration), CL (renal clearance), T-max (maximum drug concentration time), t(1/2) (elimination half-life) and Vd (volume of distribution) were analyzed using the Wilcoxon signed-rank test. No differences (p > 0.05) were observed between both formulations for any of the pharmacokinetic parameters evaluated and plasma ropivacaine concentrations...

Construction of an alkaline phosphatase-liposome system: a tool for biomineralization study

Camolezi, F. L.; Daghastanli, KRP; Magalhaes, P. P.; Pizauro, J. M.; Ciancaglini, P.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 1091-1101
ENG
Relevância na Pesquisa
37.28096%
Alkaline phosphatase is required for the mineralization of bone and cartilage. This enzyme is localized in the matrix vesicle, which plays a role key in calcifying cartilage. In this paper. we standardize a method for construction an alkaline phosphatase liposome system to mimic matrix vesicles and examine a some kinetic behavior of the incorporated enzyme. Polidocanol-solubilized alkaline phosphatase, free of detergent, was incorporated into liposomes constituted from dimyristoylphosphatidylcholine (DMPC), dilaurilphosphatidylcholine (DLPC) or dipalmitoylphosphatidylcholine (DPPC). This process was time-dependent and >95% of the enzyme was incorporated into the liposome after 4 h of incubation at 25 degreesC. Although, incorporation was more rapid when vesicles constituted from DPPC were used, the incorporation was more efficient using vesicles constituted from DMPC. The 395 nm diameter of the alkaline phosphatase-liposome system was relatively homogeneous and more stable when stored at 4 degreesC.Alkaline phosphatase was completely released from liposome system only using purified phosphatidylinositol-specific phospholipase C (PIPLC). These experiments confirm that the interaction between alkaline phosphatase and lipid bilayer of liposome is via GPI anchor of the enzyme...

Tertiary structural changes of the alpha-hemolysin from Staphylococcus aureus on association with liposome membranes

Bortoleto, R. K.; de Oliveira, AHC; Ruller, R.; Arni, R. K.; Ward, R. J.
Fonte: Academic Press Inc. Publicador: Academic Press Inc.
Tipo: Artigo de Revista Científica Formato: 47-52
ENG
Relevância na Pesquisa
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The interaction of alpha-hemolysin (also called alpha-toxin) from Staphylococcus aureus with mixed egg-yolk phosphatidylcholine/cholesterol liposomes has been investigated using the intrinsic tryptophan fluorescence emission (ITFE) signal. The ITFE intensity of alpha-hemolysin, which was obtained using a novel purification protocol, showed a triphasic increase on incubation with liposomes at low protein/lipid ratios. The first, rapid phase results in an increase in ITFE of 10%, which reflects rapid conformation changes in the alpha-hemolysin on association with the liposome membrane, the second phase of the ITFE increase is associated with a red shift from 334 to 339 nm in the maximum emission wavelength, suggesting the transition to a partially unfolded intermediate in the oligomerization process. The third phase of the ITFE intensity change demonstrates a temporal correlation with the appearance of SDS-stable oligomers. The results demonstrate the feasibility of identification of intermediate protein conformations in complex membrane-associated processes by manipulation of the liposomal membrane composition. (C) 1998 Academic Press.

Amperometric glucose biosensor based on layer-by-layer films of microperoxidase-11 and liposome-encapsulated glucose oxidase

Graca, J. S.; Oliveira, R. F. de; Moraes, M. L. de; Ferreira, M.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 37-42
ENG
Relevância na Pesquisa
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); An important step in several bioanalytical applications is the immobilization of biomolecules. Accordingly, this procedure must be carefully chosen to preserve their biological structure and fully explore their properties. For this purpose, we combined the versatility of the layer-by-layer (LbL) method for the immobilization of biomolecules with the protective behavior of liposome-encapsulated systems to fabricate a novel amperometric glucose biosensor. To obtain the biosensing unit, an LbL film of the H2O2 catalyst polypeptide microperoxidase-11 (MP-11) was assembled onto an indium-tin oxide (ITO) electrode followed by the deposition of a liposome-encapsulated glucose oxidase (GOx) layer. The biosensor response toward glucose detection showed a sensitivity of 0.91 +/- 0.09 (mu A/cm(2))/mM and a limit of detection (LOD) of 8.6 +/- 1.1 mu M, demonstrating an improved performance compared to similar biosensors with a single phospholipid-liposome or even containing a non-encapsulated GOx layer. Finally, glucose detection was also performed in a zero-lactose milk sample to demonstrate the potential of the biosensor for food analysis. (C) 2014 Elsevier B.V. All rights reserved.

Avaliação da eficacia anestesica e da concentração plasmatica da ropivacaina encapsulada em lipossomas, em anestesia odontologica; Anesthetic efficacy and plasmatic concentration of liposome-encapsulated ropivacaine in dental anesthesia

Michelle Franz Montan Braga Leite
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 27/02/2009 PT
Relevância na Pesquisa
27.350078%
Uma nova forma farmacêutica de anestésico local, encapsulado em lipossomas, vem sendo estudada na Medicina e mais atualmente em Odontologia. Os objetivos deste trabalho foram avaliar a eficácia anestésica em anestesia tópica e infiltrativa e os parâmetros farmacocinéticos da ropivacaína encapsulada em lipossomas, em 4 estudos, cruzados, duplo-cegos e com ordem de aplicação aleatória, com intervalo de 1 semana entre as aplicações. Capítulo 1: foram comparadas a eficácia da anestesia tópica e a influência na resposta pulpar da ropivacaína 2% encapsulada em lipossomas (RL2), Benzocaína 20% ( - B20), gel placebo lipossomal (PL) e gel placebo (P) aplicados em mucosa vestibular dos incisivos laterais superiores, em 40 voluntários. RL2 foi tão eficaz quanto B20 em reduzir dor à punção e na duração de anestesia em tecidos moles (p>0,05) e ambas foram superiores às formulações PL e P (p<0,05). Nenhuma das formulações exerceu influência na resposta pulpar. Capítulo 2: ropivacaína 2% encapsulada em lipossomas (RL2), ropivacaína 1% encapsulada em lipossomas (RL1), creme de lidocaína 2,5% e prilocaína 2,5% (EMLA) e gel placebo lipossomal (PL) foram avaliados quanto à eficácia em reduzir dor à punção e à injeção de anestésico local...

Effectiveness, against tuberculosis, of pseudo-ternary complexes: Peptide-DNA-cationic liposome

Rosada, Rogerio Silva; Silva, Cello Lopes; Andrade Santana, Maria Helena; Nakaie, Clovis Ryuichi; de la Torre, Lucimara Gaziola
Fonte: Elsevier; San Diego Publicador: Elsevier; San Diego
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.846492%
We report the effects of a synthetic peptide designed to act as a nuclear localization signal on the treatment of tuberculosis. The peptide contains 21 amino acid residues with the following specific domains: nuclear localization signal from SV 40T, cationic shuttle sequence, and cysteamide group at the C-terminus. The peptide was complexed with the plasmid DNAhsp65 and incorporated into cationic liposomes, forming a pseudo-ternary complex. The same cationic liposomes, composed of egg chicken L-alpha-phosphatidylcholine, 1,2-dioleoyl-3-trimethylammonium-propane, and 1,2-dioleoyl-3-trimethylammonium-propane (2:1:1 M), were previously evaluated as a gene carrier for tuberculosis immunization protocols with DNAhsp65. The pseudo-ternary complex presented a controlled size (250 nm), spherical-like shape, and various lamellae in liposomes as evaluated by transmission electron microscopy. An assay of fluorescence probe accessibility confirmed insertion of the peptide/DNA into the liposome structure. Peptide addition conferred no cytotoxicity in vitro, and similar therapeutic effects against tuberculosis were seen with four times less DNA compared with naked DNA treatment. Taken together, the results indicate that the pseudo-ternary complex is a promising gene vaccine for tuberculosis treatment. This work contributes to the development of multifunctional nanostructures in the search for strategies for in vivo DNA delivery. (C) 2011 Elsevier Inc. All rights reserved.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of the schistosomicidal efficacy of liposome - Entrapped Oxamniquine

Fonte: Instituto de Medicina Tropical Publicador: Instituto de Medicina Tropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/1997 EN
Relevância na Pesquisa
36.846492%
Oxamniquine (OXA) was sucessfully encapsulated in small unilamellar vesicles using a pH gradient method. This procedure led to a high drug encapsulation efficiency (> 85%) at a drug to lipid molar ratio of 1/10. Moreover, these liposomes were found to retain encapsulated OXA efficciently under dialysis conditions at 37º C. Liposome-entrapped OXA (LOXA), OXA, and empty liposomes were tested against Schistosoma mansoni in a murine model. LOXA produced a significant reduction of the worm burden compared to the other preparations, when inoculated by subcutaneous route (s.c.) with 10 mg OXA/kg animal one day before the infection, and 3, 7, and 14 days after. However, LOXA was not effective when given 7 days before, or 35 days after infections. OXA, in the free form, was effective in relation to the untreated group, only when administered 3 days after the infection. Maximum effect of LOXA, with 97% reduction of the parasite number, was observed when the preparation was given s.c.one day before the infection. On the other hand, LOXA inoculated intraperitoneally one day before the infection didn’t show any reduction of the parasite count. It can be concluded that LOXA is more effective than OXA for the treatment of experimental schistosomiasis...

Pharmacokinetic profile of liposome-encapsulated ropivacaine after maxillary infiltration anaesthesia

Franz-Montan,Michelle; Bergamaschi,Cristiane de Cássia; Paula,Eneida de; Groppo,Francisco C.; Ranali,José; Fraceto,Leonardo Fernandes; Volpato,Maria C.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 EN
Relevância na Pesquisa
36.846492%
The aim of this study was to determine the pharmacokinetic parameters of liposomal ropivacaine after dental anesthesia in 14 healthy volunteers. In this randomized, double-blind and crossover study, the volunteers received maxillary infiltration of liposome-encapsulated 0.5% ropivacaine and, 0.5% ropivacaine with 1:200,000 epinephrine in two different sessions. Blood samples were collected before and after (from 15 to 1440 min) the administration of either ropivacaine formulation. HPLC with UV detection was used to quantify plasma ropivacaine concentrations. The pharmacokinetic parameters AUC0-24 (area under the plasma concentration × time curve from baseline to 24 h), AUC0-∞ (area under the plasma concentration-time curve from baseline to infinity), Cmax (maximum drug concentration), CL (renal clearance), Tmax (maximum drug concentration time), t1/2 (elimination half-life) and Vd (volume of distribution) were analyzed using the Wilcoxon signed-rank test. No differences (p > 0.05) were observed between both formulations for any of the pharmacokinetic parameters evaluated and plasma ropivacaine concentrations, considering each period of time. Both formulations showed similar pharmacokinetic profiles, indicating that the liposomal formulation could be a safer option for use of this local anesthetic...

Optimization on Preparation Conditions of Salidroside Liposome and Its Immunological Activity on PCV-2 in Mice

Feng, Yibo; Zhao, Xiaojuan; Lv, Fang; Zhang, Jinqiu; Deng, Bihua; Zhao, Yanhong; Hu, Yuanliang; Wang, Deyun; Liu, Jiaguo; Lu, Yu; Bo, Ruonan; Liu, Zhenguang
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.308113%
The aim of this study was to optimize the preparation conditions of salidroside liposome with high encapsulation efficiency (EE) and to study the immunological enhancement activity of salidroside liposome as porcine circovirus type 2 virus (PCV-2) vaccine adjuvant. Response surface methodology (RSM) was selected to optimize the conditions for the preparation of salidroside liposome using Design-Expert V8.0.6 software. Three kinds of salidroside liposome adjuvants were prepared to study their adjuvant activity. BALB/c mice were immunized with PCV-2 encapsulated in different kinds of salidroside liposome adjuvants. The PCV-2-specific IgG in immunized mice serum was determined with ELISA. The results showed that when the concentration of ammonium sulfate was 0.26 mol·L−1, ethanol volume 6.5 mL, temperature 43°C, ethanol injection rate 3 mL·min−1, and salidroside liposome could be prepared with high encapsulation efficiency of 94.527%. Salidroside liposome as adjuvant could rapidly induce the production of PCV-2-specific IgG and salidroside liposome I adjuvant proved to provide the best effect among the three kinds of salidroside liposome adjuvants.

The pharmacokinetics and pharmacodynamics of liposome bupivacaine administered via a single epidural injection to healthy volunteers

Viscusi, E.; Candiotti, K.; Onel, E.; Morren, M.; Ludbrook, G.
Fonte: W B Saunders Co Publicador: W B Saunders Co
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
Relevância na Pesquisa
27.350078%
BACKGROUND AND OBJECTIVES: The objective of this study was to assess the pharmacokinetics, sensory/motor effects, and safety of epidurally administered liposome bupivacaine versus bupivacaine HCl in healthy volunteers. METHODS: Thirty subjects were randomized to receive liposome bupivacaine 89, 155, or 266 mg, or bupivacaine HCl 50 mg in a double-blind fashion. Occurrence/duration of motor blockade, pinprick/cold sensitivity, and plasma bupivacaine levels were assessed for 96 hours after study drug administration. Tolerability parameters were also assessed. RESULTS: All doses of liposome bupivacaine resulted in greater area under the curve and a longer time to observed maximum plasma concentration and terminal elimination half-life than bupivacaine HCl 50 mg. Mean maximum plasma concentration with liposome bupivacaine 89 and 155 mg (but not 266 mg) was statistically significantly lower than with bupivacaine HCl 50 mg (P < 0.001). Median duration of motor blockade with liposome bupivacaine 266 mg was 1 hour versus 2.8 hours for bupivacaine HCl. Of subjects who received liposome bupivacaine 266 mg, 29% (2/7) were unable to ambulate at 4 hours postdose versus 67% (4/6) of those receiving bupivacaine HCl. Median durations of pinprick/cold sensitivity loss were 36 and 69 hours...

Membrane electropermeabilization effects of frequency and membrane surface order on liposome leakage

Neitchev, V.; Terezova, N.; Matsumura, H.; Tomov, T.
Fonte: Murcia : F. Hernández Publicador: Murcia : F. Hernández
Tipo: Artigo de Revista Científica Formato: application/pdf
ENG
Relevância na Pesquisa
36.98853%
Liposomes containing fluorescence marke r were exposed to an alternating electric field of 80 V peak to peak square electric waves at diff e r e n t frequencies 0.01, 1, and 100 kHz to perturb the liposome permeation. The efflux of fluorescence dye after application of the electric field was measured by recording the fluorescence emission due to the complex formation reaction between the fluorescence dye and calcium ions in the bulk medium solution. Two independent sets of experiments were conducted: 1) calcium ions were present during electropulsation; and 2) they were added after electric field application. Two parameters, fluorescence emission intensity and increment of temperature of the solution in the chamber, were studied. The effect of membrane surface order on the fluorescence dye leakage from the liposomes wa s studied by addition of urea at threshold concentration before the liposomes sealed. The data demonstrate the existence of frequency dependency window at 1 kHz. Furthermore, the data were interpreted according to the theory of interactions of electromagnetic fields with highly polarized and deformed materials such as liposome particles. The urea caused an enhancement of the fluorescence dye leakage at frequency of 100 kHz. This effect could be explained as a decrease of the membrane binding rigidity due to the disordering effect of urea on the membrane lipid surface. Our conclusion is that the frequency and the membrane surface order are additional parameters that influence the processes of membrane electropermeabilization.

Avaliação do efeito do praziquantel associado a lipossomas em Schistosoma mansoni in vivo; Evaluation of the praziquantel in liposome effect in Schistosoma mansoni in vivo

Tarsila Ferraz Frezza
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 27/07/2007 PT
Relevância na Pesquisa
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Para o tratamento da esquistossomose mansônica no Brasil, a Oxamniquina (OXA) e o Praziquantel (PRZ) são os fármacos escolhidos. O primeiro tem sua produção reduzida por causa dos efeitos colaterais, carcinogênicos e mutagênicos que apresenta. O segundo tem amplo espectro de atuação e baixa toxicidade, quando comparado ao OXA, mas tem a desvantagem de ser eliminado rapidamente pelo organismo. Além disso, tem ação dependente da idade do parasito e seu uso extensivo culmina na resistência do Schistosoma mansoni ao fármaco. Assim, o estudo de novas alternativas que tornem o PRZ mais disponível no organismo, com taxa de liberação mais adequada, é necessário. Uma dessas alternativas é sua incorporação ao lipossoma (LPZ). O presente trabalho teve por objetivo analisar o efeito do PRZ incorporado a LPZ (PRZ+LPZ) pela sua ação na sobrevida dos vermes adultos de S. mansoni, linhagem BH, e alteração na postura dos ovos além da sua ação na formação de granulomas no fígado. Foram testadas cinco doses de PRZ livre e PRZ+LPZ (40; 47; 60; 250 e 300 mg/kg) em camundongos Swiss, administradas por meio da tubagem esofágica, em dose única. Os lipossomas de fosfatidilcolina foram preparados pelo método da sonicação. Os camundongos foram divididos em dois grandes grupos (um deles foi tratado após 30 dias de infecção e o outro após 45 dias) sendo que em cada grupo...

Atomic force microscopy imaging of DNA-cationic liposome complexes optimised for gene transfection into neuronal cells

Wangerek, Louise; Dahl, Hans-Hendrik; Senden, Timothy; Carlin, John; Dunstan, David Edwin; Ioannou, Panayiotis; Williamson, Robert; Forrest, S
Fonte: John Wiley & Sons Inc Publicador: John Wiley & Sons Inc
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.98853%
Background: Cationic liposomes represent an important gene delivery system due to their low immunogenicity, but are relatively inefficient, with optimisation of DNA-liposome complexes (lipoplexes) for transfection necessary for each cell type of interest.

Assessment of liposome disruption to quantify drug delivery in vitro

Nogueira, E.; Cruz, Celia F.; Loureiro, A.; Nogueira, Patrícia; Freitas, Jaime; Moreira, Alexandra; Carmo, Alexandre M.; Gomes, Andreia C.; Preto, Ana; Cavaco-Paulo, Artur
Fonte: Elsevier BV Publicador: Elsevier BV
Tipo: Artigo de Revista Científica
Publicado em /02/2016 ENG
Relevância na Pesquisa
37.084749%
Efficient liposome disruption inside the cells is a key for success with any type of drug delivery system. The efficacy of drug delivery is currently evaluated by direct visualization of labeled liposomes internalized by cells, not addressing objectively the release and distribution of the drug. Here, we propose a novel method to easily assess liposome disruption and drug release into the cytoplasm. We propose the encapsulation of the cationic dye Hoechst 34,580 to detect an increase in blue fluorescence due to its specific binding to negatively charged DNA. For that, the dye needs to be released inside the cell and translocated to the nucleus. The present approach correlates the intensity of detected fluorescent dye with liposome disruption and consequently assesses drug delivery within the cells.; Eugénia Nogueira (SFRH/BD/81269/2011), Célia F. Cruz (SFRH/BD/ 100927/2014) and Ana Loureiro (SFRH/BD/81479/2011) hold scholarships from Fundação para a Ciência e a Tecnologia (FCT). This study was funded by the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement NMP4-LA-2009-228827 NANOFOL. This study was also supported by FEDER through POFC – COMPETE and by national funds from FCT through the project PEst-UID/ BIA/4050/2013 and the strategic funding of ID/BIO/04469/2013 unit.We thank the Immuno-haemotherapy Department of Hospital de São João (Porto...

Physicochemical aspects of the liposome-wool interaction in wool dyeing

Martí Gelabert, Meritxell; Barsukov, Leonid I.; Fonollosa Argemi, Jordi; Parra Juez, José Luis; Sukhanov, Stanislav V.; Coderch Negra, M. Luisa
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artículo Formato: 22195 bytes; application/pdf
ENG
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6 pages, 6 figures, 4 tables.-- PMID: 15875831 [PubMed].-- Printed version published Apr 13, 2004.; Despite the promising application of liposomes in wool dyeing, little is known about the mechanism of liposome interactions with the wool fiber and dyestuffs. The kinetics of wool dyeing by two dyes, Acid Green 27 (hydrophobic) and Acid Green 25 (hydrophilic), were compared in three experimental protocols: (1) without liposomes, (2) in the presence of phosphatidylcholine (PC) liposomes, and (3) with wool previously treated with PC liposomes. Physicochemical interactions of liposomes with wool fibers were studied under experimental dyeing conditions with particular interest in the liposome affinity to the fiber surface and changes in the lipid composition of the wool fibers. The results obtained indicate that the presence of liposomes favors the retention of these two dyes in the dyeing bath, this effect being more pronounced in case of the hydrophobic dye. Furthermore, the liposome treatment is accompanied by substantial absorption of PC by wool fibers with simultaneous partial solubilization of their polar lipids (more evident at higher temperatures). This may result in structural modification of the cell membrane complex of wool fibers...

Avaliação imunológica de vacina de polissacarídeo meningocócico C conjugado e encapsulado em lipossomo; Immunological evaluation of meningococcal polysaccharide C conjugate vaccine and encapsulated liposome

Brito, Glauber da Costa de
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 12/12/2002 PT
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A tecnologia de conjugação melhorou a imunogeniddade de vacinas constituídas de polissacarídeo, especialmente em crianças. Polissacarídeos conjugados a proteínas carregadoras, como o toxóide tetânico, induzem resposta imunológica dependente de célula T e memória imunológica de longa duração. No entanto, esta tecnologia apresenta custo elevado. Assim, foi investigada a capaddade dos lipossomos de aumentar a resposta imunológica ao polissacarídeo C de Neisseria meningitidis (PSC). Camundongos foram imunizados com Iipossomos contendo PSC, conjugado toxóide tetânico-PSC ou PSC livre como controle, com dose de reforço constituída de PSC livre. Foram gerados anticorpos IgG e IgM contra PSC nos camundongos imunizados com conjugado ou Iipossomo. Os resultados mostram que lipossomos contendo PSC têm potencial para substituir a vadna conjugada toxóide tetânico-PSC.; Conjugation technology has improved the immunogenicity of polysaccharide vaccines, specially in small children. Polysaccharides conjugated to various carrier proteins, e.g. tetanus toxoid, stimulate a T cell-dependent antibody response and induce a long-term immunological memory. However, protein-polysaccharide conjugation technology is expensive and this could constitute an important drawback. Thus...