Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 24
Filtrar
1.
Rev. bras. ginecol. obstet ; 45(12): 780-789, Dec. 2023. graf
Artigo em Inglês | LILACS | ID: biblio-1529912

RESUMO

Abstract Objective To compare the patterns of systemic inflammatory response in women with epithelial ovarian cancer (EOC) or no evidence of malignant disease, as well as to evaluate the profile of systemic inflammatory responses in type-1 and type-2 tumors. This is a non-invasive and indirect way to assess both tumor activity and the role of the inflammatory pattern during pro- and antitumor responses. Materials and Methods We performed a prospective evaluation of 56 patients: 30 women without evidence of malignant disease and 26 women with EOC. The plasma quantification of cytokines, chemokines, and microparticles (MPs) was performed using flow cytometry. Results Plasma levels of proinflammatory cytokines interleukin-12 (IL12), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α) interleukin-1 beta (IL-1β), and interleukin-10 (IL-10), and C-X-C motif chemokine ligand 9 (CXCL-9) and C-X-C motif chemokine ligand 10 (CXCL-10) were significantly higher in patients with EOC than in those in the control group. Plasma levels of cytokine interleukin-17A (IL-17A) and MPs derived from endothelial cells were lower in patients with EOC than in the control group. The frequency of leukocytes and MPs derived from endothelial cells was higher in type-2 tumors than in those without malignancy. We observed an expressive number of inflammatory/regulatory cytokines and chemokines in the cases of EOC, as well as negative and positive correlations involving them, which leads to a higher complexity of these networks. Conclusion The present study showed that, through the development of networks consisting of cytokines, chemokines, and MPs, there is a greater systemic inflammatory response in patients with EOC and a more complex correlation of these biomarkers in type-2 tumors.


Resumo Objetivo Comparar os padrões de resposta inflamatória sistêmica em mulheres com câncer epitelial de ovário (CEO) ou sem evidência de doença maligna, bem como avaliar o perfil de respostas inflamatórias sistêmicas em tumores dos tipos 1 e 2. Esta é uma forma não invasiva e indireta de avaliar tanto a atividade tumoral quanto o papel do padrão inflamatório durante as respostas pró- e antitumorais. Métodos Ao todo, 56 pacientes foram avaliados prospectivamente: 30 mulheres sem evidência de doença maligna e 26 mulheres com CEO. A quantificação plasmática de citocinas, quimiocinas e micropartículas (MPs) foi realizada por citometria de fluxo. Resultados Os níveis plasmáticos das citocinas pró-inflamatórias interleucina-12 (IL12), interleucina-6 (IL-6), fator de necrose tumoral alfa (tumor necrosis factor alpha, TNF-α, em inglês), interleucina-1 beta (IL-1β), e interleucina-10 (IL-10), e da quimiocina de motivo C-X-C 9 (CXCL-9) e da quimiocina de motivo C-X-C 10 (CXCL-10) foram significativamente maiores em pacientes com EOC do que nos controles. Os níveis plasmáticos da citocina interleucina-17A (IL17A) e MPs derivados de células endoteliais foram menores em pacientes com CEO do que no grupo de controle. A frequência de leucócitos e de MPs derivadas de células endoteliais foi maior nos tumores de tipo 2 do que naqueles sem malignidade. Observou-se um número expressivo de citocinas e quimiocinas inflamatórias/regulatórias nos casos de CEO, além de correlações negativas e positivas entre elas, o que leva a uma maior complexidade dessas redes. Conclusão Este estudo mostrou que, por meio da construção de redes compostas por citocinas, quimiocinas e MPs, há maior resposta inflamatória sistêmica em pacientes com CEO e correlação mais complexa desses biomarcadores em tumores de tipo 2.


Assuntos
Humanos , Feminino , Neoplasias Ovarianas , Citocinas , Quimiocinas , Inflamação
2.
Rev. Inst. Adolfo Lutz ; 81: e37345, mar.1, 2022. tab, graf
Artigo em Inglês | LILACS, CONASS, Coleciona SUS, Sec. Est. Saúde SP, VETINDEX, SESSP-ACVSES, SESSP-IALPROD, Sec. Est. Saúde SP, SESSP-IALACERVO | ID: biblio-1391112

RESUMO

The present study aims to correlate the sample-to-cutoff ratios (S/CO) distributions of reactive results for HTLV-1/2 antibodies with the detection of proviral DNA in a population of blood donor candidates. It was carried out a retrospective data search of 632 HTLV-1/2 reactive samples, submitted to confirmatory testing from January 2015 to December 2019. Serological screening was performed by chemiluminescent microparticle immunoassay Architect rHTLV-I/II, whereas confirmatory testing was performed by in-house real-time polymerase chain reaction method. 496 out of 632 samples (78%) had undetectable HTLV-1/2 proviral DNA and 136 (22%) had detectable proviral DNA. HTLV infection was not confirmed in any individual for whom the S/CO ratio value was <4, and proviral DNA detection rates gradually escalated as S/CO ratio values increased. The sensitivity and predictive positive value found for the Architect rHTLV-I/II was 100% and 22%, respectively. The receiver operating characteristic (ROC) curve analysis showed that the optimal S/CO ratio value for predicting the presence of HTLV-1/2 was 18.11. High S/CO ratios were more associated with the detection of proviral DNA. The S/CO ratio value <4 suggests excluding true HTLV infection and the risk of blood transmission (AU).


O estudo tem como objetivo correlacionar às distribuições das razões sample-to-cutoff (S/CO) de resultados reagentes para anticorpos HTLV-1/2 com a detecção de DNA proviral em uma população de candidatos à doação de sangue. Realizou-se uma busca retrospectiva de dados de 632 amostras reagentes para HTLV-1/2 submetidas à testagem confirmatória entre janeiro de 2015 a dezembro de 2019. A triagem sorológica foi realizada pelo imunoensaio quimioluminescente de micropartículas Architect rHTLV-I/II, enquanto o teste confirmatório foi realizado pelo método de PCR em tempo real in-house. 496 de 632 amostras (78%) apresentaram DNA proviral indetectável e 136 (22%) apresentaram DNA proviral detectável. A infecção por HTLV não foi confirmada em nenhum indivíduo com valor de S/CO <4 e as taxas de detecção de DNA proviral escalonaram gradualmente à medida que as razões S/CO aumentaram. A sensibilidade e valor preditivo positivo encontrados para o Architect rHTLV-I/II foram 100% e 22%, respectivamente. Utilizando análise de curva ROC, o valor de razão S/CO ideal para predizer a presença de DNA proviral foi de 18,11. Razões S/CO elevadas foram mais associadas à detecção de DNA proviral. Em suma, o valor de S/CO <4 sugere a exclusão de infecção por HTLV e o risco de transmissão pelo sangue (AU).


Assuntos
Doadores de Sangue , Imunoensaio , Vírus Linfotrópico T Tipo 1 Humano , Vírus Linfotrópico T Tipo 2 Humano , Reação em Cadeia da Polimerase em Tempo Real , Infecções
3.
Arch. bronconeumol. (Ed. impr.) ; 58(2): 117-124, feb. 2022. tab, ilus, graf
Artigo em Inglês | IBECS | ID: ibc-203025

RESUMO

Introduction. Growing evidence shows a hypercoagulable state in obstructive sleep apnea (OSA) that could be a risk factor for thromboembolic disease. Objectives We aimed to elucidate mechanisms involved in the procoagulant profile observed in patients with OSA and to investigate the potential utility of global tests in its characterization. Methods Thirty-eight patients with severe OSA without previous history of thrombosis and nineteen healthy age- and sex-matched controls were included. Kinetic of clot formation was determined using rotational thromboelastometry. Haemostatic capacity of plasma and microparticles was determined by Calibrated Automated Thrombinography. Platelet surface receptors, activation markers and formation of platelet/leukocytes aggregates were analyzed by flow cytometry. Results Thromboelastometry showed a procoagulant state in patients with OSA that did not seem to be related to a basal activation of platelets but by the increased existence of platelet/leukocyte aggregates. Patients with OSA presented many signs of endothelial damage such as increased plasma levels of E-selectin and cfDNA and enhanced thrombin generation due to the presence of microparticles rich in tissue-factor, which is related to OSA severity. Conclusions OSA induces an enhancement in the dynamics of clot formation which appears to be caused by at least two pathological mechanisms. First, a greater formation of platelet-leukocyte aggregates; secondly, endothelial damage which provokes a greater procoagulant potential due to the increase in tissue factor-rich microparticles. Moreover, this study has identified thromboelastometry and thrombin generation assay as useful tools to evaluate the prothrombotic state in these patients.


Introducción Existen pruebas crecientes que muestran un estado de hipercoagulabilidad en la apnea obstructiva del sueño (AOS) que podría ser un factor de riesgo de desarrollar enfermedad tromboembólica. Objetivos Nuestro objetivo fue dilucidar los mecanismos involucrados en el perfil procoagulante que se ha observado en los pacientes con AOS e investigar la posible utilidad de las pruebas globales en su caracterización. Métodos Se incluyeron 38 pacientes con AOS grave sin antecedentes de trombosis y 19 controles sanos emparejados por edad y sexo. La cinética de la formación del coágulo se determinó mediante tromboelastometría rotacional. La capacidad hemostática del plasma y las micropartículas se determinó mediante trombinografía automatizada calibrada. Los receptores de la membrana plaquetaria, los marcadores de activación plaquetaria y la formación de agregados de plaquetas-leucocitos se analizaron mediante citometría de flujo. Resultados La tromboelastometría mostró un estado procoagulante en pacientes con AOS que no parecía estar relacionado con una activación basal de las plaquetas, sino por el aumento de agregados de plaquetas-leucocitos. Los pacientes con AOS presentaban muchos signos de daño endotelial, como un aumento de los niveles plasmáticos de E-selectina y ADNcf y una mayor generación de trombina debido a la presencia de micropartículas ricas en factor tisular, que se relaciona con la gravedad de la AOS. Conclusiones La AOS induce un aumento de la dinámica de la formación de coágulos que parece estar causada por al menos 2 mecanismos patológicos. Primero, una mayor formación de agregados plaquetas-leucocitos; segundo, el daño endotelial que provoca un mayor potencial procoagulante debido al aumento de micropartículas ricas en factor tisular. Además, este estudio ha identificado la tromboelastometría y el ensayo de generación de trombina como herramientas útiles para evaluar el estado protrombótico en estos pacientes.


Assuntos
Humanos , Ciências da Saúde , Síndromes da Apneia do Sono , Apneia Obstrutiva do Sono , Trombofilia
4.
Arch Bronconeumol ; 58(2): 117-124, 2022 Feb.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-33461785

RESUMO

INTRODUCTION: Growing evidence shows a hypercoagulable state in obstructive sleep apnea (OSA) that could be a risk factor for thromboembolic disease. OBJECTIVES: We aimed to elucidate mechanisms involved in the procoagulant profile observed in patients with OSA and to investigate the potential utility of global tests in its characterization. METHODS: Thirty-eight patients with severe OSA without previous history of thrombosis and nineteen healthy age- and sex-matched controls were included. Kinetic of clot formation was determined using rotational thromboelastometry. Haemostatic capacity of plasma and microparticles was determined by Calibrated Automated Thrombinography. Platelet surface receptors, activation markers and formation of platelet/leukocytes aggregates were analyzed by flow cytometry. RESULTS: Thromboelastometry showed a procoagulant state in patients with OSA that did not seem to be related to a basal activation of platelets but by the increased existence of platelet/leukocyte aggregates. Patients with OSA presented many signs of endothelial damage such as increased plasma levels of E-selectin and cfDNA and enhanced thrombin generation due to the presence of microparticles rich in tissue-factor, which is related to OSA severity. CONCLUSIONS: OSA induces an enhancement in the dynamics of clot formation which appears to be caused by at least two pathological mechanisms. First, a greater formation of platelet-leukocyte aggregates; secondly, endothelial damage which provokes a greater procoagulant potential due to the increase in tissue factor-rich microparticles. Moreover, this study has identified thromboelastometry and thrombin generation assay as useful tools to evaluate the prothrombotic state in these patients.

5.
Biomédica (Bogotá) ; 41(3): 555-589, jul.-set. 2021. tab, graf
Artigo em Espanhol | LILACS | ID: biblio-1345403

RESUMO

Resumen En la última década se ha incrementado el número de estudios y publicaciones sobre las vesículas extracelulares y los exosomas. En Colombia, ha habido interés y avances en su estudio, lo que se evidencia en el aumento de publicaciones y proyectos de investigación. Sin embargo, este es un campo de investigación aún en desarrollo, con desafíos analíticos y limitaciones técnicas, por lo cual, en el planteamiento de los proyectos de investigación y desarrollo, es necesario considerar cuál es el estado del campo científico a nivel mundial en cuanto a la nomenclatura y la clasificación de las vesículas extracelulares, las técnicas, recursos, requisitos y especificaciones de calidad y las instituciones que regulan el campo. La respuesta a esta pregunta permitirá desarrollar estudios que cumplan con los estándares internacionales, y las exigencias y recomendaciones institucionales. Sin embargo, la información científica disponible se encuentra dispersa y no todos los aspectos son tratados a cabalidad. En este actualización se condensa la información disponible y se presentan los términos oficiales para denominar las vesículas extracelulares y la nomenclatura aceptada actualmente, así como la evolución del campo, la homogenización de los parámetros experimentales, el establecimiento de autoridades científicas, instituciones y recursos, y las recomendaciones que se han generado a nivel mundial para el desarrollo de investigaciones en vesículas extracelulares, incluidos su aislamiento, caracterización y estudio funcional. Por último, se analiza el contexto nacional de una forma crítica, teniendo en cuenta las fortalezas institucionales, los errores usualmente cometidos, y las técnicas y tecnologías analíticas disponibles.


Abstract In the last decade, the number of studies and publications on extracellular vesicles (EV) and exosomes has boomed. Colombia has displayed interest and progress in their study as shown in the increase of research project publications and products. However, this research field is still developing and has its own analytical challenges and technical limitations. For planning research projects and developing EV studies it is necessary to consider what is the state of the scientific field worldwide concerning EV nomenclature and classification, available techniques, resources, requirements and quality specifications, and the institutions that regulate the field. Answering this question will elicit EV studies that comply with international standards and respond to institutional demands and recommendations. However, the scientific information available is scattered and not all the aspects are considered in full. In this update, the available information is condensed and the official terms and currently defined nomenclature is presented, as well as the evolution of the field, the homogenization of the experimental parameters, the establishment of scientific authorities, institutions, and resources, and the recommendations generated worldwide for their development and research including their isolation, characterization, and functional studies. Finally, I analyzed the national context in a critical way, considering institutional strengths, common mistakes, and available analytical techniques and technologies.


Assuntos
Vesículas Extracelulares , Técnicas de Química Analítica , Guia Informativo , Micropartículas Derivadas de Células , Exossomos , Fenômenos Químicos , Terminologia como Assunto
6.
Arq. bras. cardiol ; 109(2): 156-164, Aug. 2017. tab, graf
Artigo em Inglês | LILACS | ID: biblio-887908

RESUMO

Abstract Background: Cell-derived microvesicles (MVs) are vesicles released from activated or apoptotic cells. However, the levels of MVs in myocardial infarction have been found inconsistent in researches. Objective: To assess the association between MVs and myocardial infarction by conducting a meta-analysis. Methods: A systematic literature search on PubMed, Embase, Cochran, Google Scholar electronic database was conducted. Comparison of the MVs levels between myocardial infarction patients and healthy persons were included in our study. Standard Mean Difference (SMD) and 95% confidence interval (CI) in groups were calculated and meta-analyzed. Results: 11 studies with a total of 436 participants were included. Compared with the health persons, AMVs [SMD = 3.65, 95% CI (1.03, 6.27)], PMVs [SMD = 2.88, 95% CI (1.82, 3.93),] and EMVs [SMD = 2.73, 95% CI (1.13, 4.34)], levels were higher in patients with myocardial infarction. However, LMVs levels [SMD = 0.73, 95% CI (-0.57, 2.03)] were not changed significantly in patients with myocardial infarction. Conclusions: AMVs, PMVs and EMVs might be potential biomarkers for myocardial infarction.


Resumo Fundamentos: As microvesículas derivadas de células (MVs) são vesículas liberadas de células ativadas ou apoptóticas. No entanto, os níveis de MVs no infarto do miocárdio foram encontrados inconsistentes nas pesquisas. Objetivo: Avaliar a associação entre MV e infarto do miocárdio por meio de uma meta-análise. Métodos: Foi realizada uma pesquisa sistemática na literatura em PubMed, Embase, Cochran e no banco de dados eletrônico do Google Scholar. Uma comparação dos níveis de MV entre pacientes com infarto do miocárdio e pessoas saudáveis foi incluída no nosso estudo. A Diferença Média Padrão (DMP) e o intervalo de confiança (IC) de 95% nos grupos foram calculadas e meta-analisadas. Resultados: Foram incluídos 11 estudos com um total de 436 participantes. Em comparação com as pessoas saudáveis, as MVA [DMP = 3,65, IC 95% (1,03, 6,27)], MVPs [DMP = 2,88, IC 95% (1,82, 3,93)] e MVEs [DMP = 2,73, IC 95% (1,13, 4.34)], foram maiores em pacientes com infarto do miocárdio. No entanto, os níveis de MVL [DMP = 0,73, IC 95% (-0,57, 2,03)] não foram alterados significativamente em pacientes com infarto do miocárdio. Conclusões: MVAs, MVPs e MVEs podem ser biomarcadores potenciais para o infarto do miocárdio.

8.
Int. j. morphol ; 35(1): 310-318, Mar. 2017. ilus
Artigo em Espanhol | LILACS | ID: biblio-840971

RESUMO

La proteína morfogenética ósea (BMP), es una proteína endógena que ha mostrado efectos significativos en la promoción de la formación ósea. El uso de BMP ha sido descrito en la reconstrucción de defectos óseos de origen traumáticos y patológicos, incluyendo la fisura alveolar, el aumento de reborde alveolar, la elevación de seno maxilar, el injerto de alveolo post-extracción, y la cirugía perimplantaria entre otros. A pesar de las ventajas asociadas al uso de BMP y que en la actualidad se aplica en combinación con matrices de colágeno, ciertas propiedades tales como su baja resistencia mecánica y su elevada tasa de liberación inicial disminuyen su eficacia en la formación ósea. En este contexto, el desarrollo de nuevos sistemas de liberación prolongada de BMP que permitan la quimiotaxis de células mesenquimáticas y su posterior diferenciación a osteoblastos representa un desafío con alto potencial clínico para la estimulación de la formación ósea. En este trabajo, se describe el uso de BMP en la reconstrucción de fisuras alveolares y en particular se discuten las ventajas de su administración en micropartículas poliméricas comosistemas de liberación de BMP (rhBMP-2) con promisorias aplicaciones en la estimulación de la formación ósea.


Bone morphogenetic protein (BMP) is an endogenous protein that has shown significant effects in the promotion of bone formation. BMP also has been described in the reconstruction of traumatic and pathological bone defects, including alveolar cleft, alveolar ridge augmentation, maxillary sinus elevation, and applications in post-extraction alveolus graft, and peri-implant surgery among others. Despite the advantages associated with the use of BMP, currently is applied in combination with collagen matrices, which has certain properties such as low mechanical resistance and a high burst initial release that diminish its effectiveness in bone formation. In this context, the development of novel systems with greater mechanical resistance and prolonged release of BMP, that lead to chemotaxis of mesenchymal cells, following by its differentiation to osteoblasts represents a major challenge that holds outstanding clinical potential for the stimulation of bone formation. In this paper, we describe the use of BMP for the reconstruction of alveolar clefts, and its advantages being administrated in polymeric microparticles as sustain release system with promising applications in the stimulation of bone formation.


Assuntos
Humanos , Processo Alveolar/cirurgia , Proteína Morfogenética Óssea 2/uso terapêutico , Proteínas Morfogenéticas Ósseas/uso terapêutico , Proteínas Recombinantes/uso terapêutico , Regeneração Óssea/efeitos dos fármacos , Fissura Palatina/cirurgia , Nanopartículas
9.
Clin Investig Arterioscler ; 28(4): 167-77, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27363781

RESUMO

INTRODUCTION: microRNA (miRNA) expression profile of extracellular vesicles is a potential tool for clinical practice. Despite the key role of vascular smooth muscle cells (VSMC) in cardiovascular pathology, there is limited information about the presence of miRNAs in microparticles secreted by this cell type, including human coronary artery smooth muscle cells (HCASMC). Here, we tested whether HCASMC-derived microparticles contain miRNAs and the value of these miRNAs as biomarkers. METHODS: HCASMC and explants from atherosclerotic or non-atherosclerotic areas were obtained from coronary arteries of patients undergoing heart transplant. Plasma samples were collected from: normocholesterolemic controls (N=12) and familial hypercholesterolemia (FH) patients (N=12). Both groups were strictly matched for age, sex and cardiovascular risk factors. Microparticle (0.1-1µm) isolation and characterization was performed using standard techniques. VSMC-enriched miRNAs expression (miR-21-5p, -143-3p, -145-5p, -221-3p and -222-3p) was analyzed using RT-qPCR. RESULTS: Total RNA isolated from HCASMC-derived microparticles contained small RNAs, including VSMC-enriched miRNAs. Exposition of HCASMC to pathophysiological conditions, such as hypercholesterolemia, induced a decrease in the expression level of miR-143-3p and miR-222-3p in microparticles, not in cells. Expression levels of miR-222-3p were lower in circulating microparticles from FH patients compared to normocholesterolemic controls. Microparticles derived from atherosclerotic plaque areas showed a decreased level of miR-143-3p and miR-222-3p compared to non-atherosclerotic areas. CONCLUSIONS: We demonstrated for the first time that microparticles secreted by HCASMC contain microRNAs. Hypercholesterolemia alters the microRNA profile of HCASMC-derived microparticles. The miRNA signature of HCASMC-derived microparticles is a source of cardiovascular biomarkers.


Assuntos
Doenças Cardiovasculares/fisiopatologia , Micropartículas Derivadas de Células/metabolismo , MicroRNAs/genética , Miócitos de Músculo Liso/metabolismo , Adulto , Aterosclerose/patologia , Biomarcadores/metabolismo , Doenças Cardiovasculares/etiologia , Estudos de Casos e Controles , Células Cultivadas , Vasos Coronários/citologia , Vasos Coronários/patologia , Feminino , Humanos , Hipercolesterolemia/fisiopatologia , Hiperlipoproteinemia Tipo II , Masculino , Pessoa de Meia-Idade , Placa Aterosclerótica/patologia , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Risco
10.
Rev Esp Cardiol (Engl Ed) ; 69(7): 672-80, 2016 Jul.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-27103451

RESUMO

INTRODUCTION AND OBJECTIVES: Diabetes mellitus is associated with an enhanced risk for cardiovascular disease and its prevalence is increasing. Diabetes induces metabolic stress on blood and vascular cells, promoting platelet activation and vascular dysfunction. The level of vascular cell activation can be measured by the number and phenotype of microparticles found in the circulation. The aim of this study was to investigate the effect of a platelet-inhibitory dose of aspirin on the number and type of microparticles shed to the circulation. METHODS: Forty-three diabetic patients were enrolled in the study and received a daily dose of 100mg of aspirin for 10 days to cover the average platelet life-span in the circulation. Before and after the intervention period, circulating microparticles were characterized and quantified by flow cytometry. RESULTS: Type 1 diabetic patients had about twice the number of tissue factor-positive circulating microparticles (derived both from platelets and monocytes) and endothelial-derived E-selectin positive microparticles than type 2 diabetic patients. Aspirin therapy significantly inhibited platelets since cyclooxygenase 1 derived thromboxane generation levels were reduced by 99%. Microparticles derived from erythrocytes, activated monocytes, and smooth muscle cells were significantly reduced after 10 days of aspirin administration. CONCLUSIONS: These results indicate that: a) vascular and blood cells in type 1 diabetic patients are exposed to more sustained stress shown by their specific microparticle origin and levels; b) aspirin therapy inhibits vascular wall cell activation and microparticle shedding, and c) the effects of aspirin are similar in type 1 and 2 diabetes.


Assuntos
Aspirina/administração & dosagem , Plaquetas/metabolismo , Doenças Cardiovasculares/prevenção & controle , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 2/complicações , Eritrócitos/metabolismo , Músculo Liso Vascular/patologia , Adulto , Idoso , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/etiologia , Micropartículas Derivadas de Células/metabolismo , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 2/sangue , Relação Dose-Resposta a Droga , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Monócitos/metabolismo , Músculo Liso Vascular/fisiopatologia , Ativação Plaquetária , Inibidores da Agregação Plaquetária/administração & dosagem
11.
Med. lab ; 22(11/12): 585-592, nov-dic. 2016.
Artigo em Espanhol | LILACS | ID: biblio-883399

RESUMO

Código SCPC (Sociedad Colombiana de Patología Clínica): 58200. Código CUPS (Codificación Única de Procedimientos en Salud): 906218. Sección: Infecciosas. Nivel de complejidad: alto. Metodología: inmunoanálisis quimioluminiscente de micropartículas (CMIA). Sinónimos: HAVAb-IgM, HAV IgM. Definición El ensayo ARCHITECT HAVAb-IgM es un inmunoanálisis quimioluminiscente de micropartículas (CMIA) para la detección cualitativa de anticuerpos IgM frente al virus de la hepatitis A (IgM anti-VHA) en suero y plasma humanos, útil en el diagnóstico de las infecciones agudas o recientes por el virus de la hepatitis A. Espectro clínico de aplicación El virus de la hepatitis A (VHA) tiene un genoma tipo ARN, pertenece a la familia Picornaviridae, género Hepatovirus, especie Hepatitis A virus, del cual se conoce un solo serotipo y es el agente causal de la hepatitis A, una de las infecciones de transmisión alimentaria más frecuentes, estrechamente asociada a la falta de agua potable, saneamiento deficiente y mala higiene personal. Los seres humanos son reservorios del virus de la hepatitis A y en raras ocasiones los chimpancés y otros primates no humanos. La hepatitis A es una infección viral común en la población infantil, con frecuencia subclínica, que en ocasiones cursa con manifestaciones clínicas sugestivas del diagnóstico; sin embargo, la confirmación solo se puede realizar mediante pruebas de laboratorio. Esta enfermedad causa una elevada morbilidad en la población adulta y ocasionalmente puede llegar a tener consecuencias graves, como insuficiencia hepática aguda de evolución fatal. El virus de la hepatitis A persiste en el medio y puede resistir los procesos de producción de alimentos usados habitualmente para inactivar y controlar las bacterias patógenas. (AU)


Assuntos
Humanos
12.
Int. j. cardiovasc. sci. (Impr.) ; 28(6): 511-513, nov.-dez. 2015.
Artigo em Português | LILACS | ID: lil-788770

RESUMO

Nas últimas décadas, houve redução da mortalidade por infarto agudo do miocárdio com supradesnivelamento do segmento ST (IAMCSST) associada a um conjunto de ações que une avanços tecnológicos e políticas públicas. Entretanto, sua característica de doença tempo-dependente ainda é responsável por elevado número de casos de morte súbita e as consequências da reperfusão tardia ou ineficiente estão relacionadas à ocorrência de insuficiência cardíaca e maior morbimortalidade. Sob esse ponto de vista, foram revisados três diferentes aspectos: o impacto das arritmias ventriculares no atendimento pré-hospitalar; a influência do fator de Von Willebrand e o papel das micropartículas no diagnóstico da doença.


In the past decades, there was a reduction in mortality from ST segment elevation acute myocardial infarction (STEMI) associated with a set of actions combining technological advances and public policies. However, its characteristic of a time-dependent disease is still responsible for a high number of cases of sudden death and the consequences of late or inefficient reperfusion are related to heart failure and increased morbidity and mortality. From this point of view, three different aspects were reviewed: the impact of ventricular arrhythmias in prehospital care; the influence of Von Willebrand factor and the role of microparticles in the diagnosis of the disease.


Assuntos
Humanos , Adulto , Fibrilação Atrial , Infarto do Miocárdio/complicações , Síndrome Coronariana Aguda/diagnóstico , Fator de von Willebrand , Arritmias Cardíacas , Micropartículas Derivadas de Células
13.
Rev Esp Cardiol (Engl Ed) ; 68(11): 951-8, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25819989

RESUMO

INTRODUCTION AND OBJECTIVES: Microparticles are markers for cell activation and apoptosis and could provide valuable information that is not available from clinical data. This study assesses the clinical and biological relationship of small-sized microparticles in different forms of ischemic systolic heart failure and their relation to markers of inflammation and repair. METHODS: We compared 49 patients with acute heart failure, 39 with stable heart failure and 25 patients with stable coronary artery disease. Small-size microparticles counts were determined by high-resolution flow cytometry. Moreover, 3 different monocyte subpopulations and their expression of inflammatory and adhesive scavenger receptors were analyzed using a conventional flow cytometer. RESULTS: Endothelial CD144+ microparticle counts were decreased in heart failure groups (P=.008). Annexin V-binding microparticle counts were found increased in heart failure (P=.024) and in patients with lower functional class (P=.013). Platelet CD42b+ microparticle counts positively correlated with left ventricular ejection fraction (P=.006), and annexin V-binding microparticle counts with interleukin-6 levels in stable heart failure (P=.034). Annexin V-binding microparticle counts in the acute status strongly correlated with toll-like receptor-4 expression on all monocyte subsets (all P<.01). Three months after admission with acute heart failure, annexin V-binding microparticle counts were positively correlated with receptors for interleukin-6, CD163 and CD204 (all P<.05). CONCLUSIONS: Annexin V-binding microparticle counts constitute valuable hallmarks of acute decompensated state in systolic heart failure. The observed relationship between small-size annexin V-binding microparticles and scavenger receptors supports their involvement in the progression of the acute response to injury, and thus their contribution to the pathogenesis of acute decompensated heart failure.


Assuntos
Plaquetas/metabolismo , Micropartículas Derivadas de Células/metabolismo , Células Endoteliais/metabolismo , Insuficiência Cardíaca/metabolismo , Isquemia Miocárdica/metabolismo , Idoso , Anexina A5 , Antígenos CD , Antígenos de Diferenciação Mielomonocítica , Apoptose , Biomarcadores , Plaquetas/citologia , Caderinas , Estudos de Casos e Controles , Doença da Artéria Coronariana/metabolismo , Células Endoteliais/citologia , Feminino , Citometria de Fluxo , Insuficiência Cardíaca/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Monócitos/citologia , Monócitos/metabolismo , Isquemia Miocárdica/complicações , Complexo Glicoproteico GPIb-IX de Plaquetas , Estudos Prospectivos , Receptores de Superfície Celular , Receptores de Interleucina-6 , Receptores Depuradores , Receptores Depuradores Classe A , Volume Sistólico , Receptor 4 Toll-Like
14.
Arq. bras. cardiol ; 104(2): 169-174, 02/2015. tab, graf
Artigo em Inglês | LILACS | ID: lil-741150

RESUMO

Primary prevention of cardiovascular disease is a choice of great relevance because of its impact on health. Some biomarkers, such as microparticles derived from different cell populations, have been considered useful in the assessment of cardiovascular disease. Microparticles are released by the membrane structures of different cell types upon activation or apoptosis, and are present in the plasma of healthy individuals (in levels considered physiological) and in patients with different pathologies. Many studies have suggested an association between microparticles and different pathological conditions, mainly the relationship with the development of cardiovascular diseases. Moreover, the effects of different lipid-lowering therapies have been described in regard to measurement of microparticles. The studies are still controversial regarding the levels of microparticles that can be considered pathological. In addition, the methodologies used still vary, suggesting the need for standardization of the different protocols applied, aiming at using microparticles as biomarkers in clinical practice.


A prevenção primária da doença cardiovascular constitui uma opção de grande relevância pelos seus impactos na saúde. Alguns biomarcadores têm sido considerados úteis na avaliação da doença cardiovascular, dentre eles micropartículas originadas de diferentes populações de células. Micropartículas são estruturas liberadas pela membrana de diferentes tipos celulares após ativação ou apoptose, presentes tanto no plasma de indivíduos saudáveis (níveis considerados fisiológicos) quanto em portadores de diferentes doenças. Muitos estudos têm sugerido uma associação entre micropartículas e diferentes condições patológicas, destacando-se a relação com o desenvolvimento das doenças cardiovasculares. Além disso, têm sido descritos os efeitos de diferentes terapias hipolipemiantes na mensuração de micropartículas. Os estudos ainda são controversos quanto aos níveis de micropartículas que possam ser considerados patológicos, e os métodos utilizados ainda são variados, o que sugere a necessidade da padronização dos diferentes protocolos utilizados, visando à utilização de micropartículas como biomarcadores úteis na prática clínica.


Assuntos
Humanos , Doenças Cardiovasculares/patologia , Micropartículas Derivadas de Células/patologia , Biomarcadores , Plaquetas/patologia , Diabetes Mellitus/patologia , Células Endoteliais/patologia , Endotélio/patologia , Ilustração Médica , Monócitos/patologia
15.
Full dent. sci ; 5(19): 433-439, jul. 2014.
Artigo em Português | LILACS, BBO - Odontologia | ID: lil-726524

RESUMO

Atualmente, esforços têm sido concentrados na busca de um implante carreador de proteína morfogenética óssea que possa aperfeiçoar a sua aplicação. As proteínas morfogenéticas ósseas são glicoproteínas responsáveis pelo recrutamento de células osteoprogenitoras para os locais de formação óssea. Dessa maneira, o objetivo deste estudo é revisar a literatura sobre sistemas carreadores para a proteína morfogenética óssea. Estes vêm sendo estudados na tentativa de melhorar o efeito terapêutico através do prolongamento e/ou controle da sua liberação, aumentando, consequentemente, a sua eficácia terapêutica. Essa revisão bibliográfica sugere que as micropartículas biodegradáveis podem ser utilizadas como sistemas carreadores de proteína morfogenética óssea.


Currently, efforts have been concentrated in the search for an implant carrier of bone morphogenetic protein that can enhance its application. The bone morphogenetic proteins are glycoproteins responsible for the recruitment of osteoprogenitor cells to sites of bone formation. Then, the objective of this study was to review the literature about the systems carriers for bone morphogenetic protein. These carriers have been studied in an attempt to improve the therapeutic efficacy by extension and/or control of their release, and therefore increasing their therapeutic efficacy. This literature review suggests that the microparticles can be used as carrier systems for bone morphogenetic protein


Assuntos
Células-Tronco/metabolismo , Colágeno/uso terapêutico , /uso terapêutico , /uso terapêutico , /uso terapêutico , Regeneração Óssea/fisiologia , Transplante Ósseo/reabilitação
16.
São Paulo; s.n; 2014. [91] p. ilus, graf, tab.
Tese em Português | LILACS | ID: biblio-870823

RESUMO

A Trombocitopenia imune (PTI) é uma doença imuno mediada adquirida de adultos e crianças caracterizada por plaquetopenia transitória ou persistente, onde o grau de plaquetopenia aumenta o risco de sangramento. Geralmente, os pacientes apresentam manifestações clínicas apenas em plaquetopenias abaixo de 50x103/mm3, e contagem de plaquetas entre 100 e 150 x103/mm3, se estável por mais de 6 meses, necessariamente não indica uma condição patológica. Tem sido sugerido diferentes processos fisiopatológicos relacionados às plaquetas de acordo com a intensidade da plaquetopenia, e que alterações na megacariocitopoiese e diminuição da sobrevida plaquetária são eventos determinantes na PTI. Contagem de plaquetas reticuladas em citometria de fluxo é um teste muito útil para avaliação da plaquetopenia, pois reflete a atividade megacariocitopoiética, destruição das plaquetas e a própria contagem de plaquetas. Tanto as plaquetas quanto os megacariócitos apresentam a via intrínseca da apoptose. A atividade dos principais mediadores da apoptose intrínseca, como Bax a Bak, é regulada por proteínas anti-apoptótica da família Bcl-2, tais como Bcl-xL. Um balanço entre Bcl-xL e Bax regula a sobrevivência plaquetária. Pacientes de PTI apresentam aumento da ativação plaquetária e da formação de micropartículas derivadas de plaquetas (MPP). Nosso objetivo foi avaliar a relação entre produção e apoptose plaquetária, e associá-la com a ativação plaquetária e a formação de MPP nos diferentes graus de intensidade da PTI. Os pacientes recrutados foram diagnosticados para trombocitopenia imune (PTI) primária, "idiopática", não esplenectomizados, acompanhados regularmente no ambulatório de Doenças Hemorrágicas e Trombóticas, do Serviço de Hematologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, e foram divididos grupos de acordo com contagem de plaquetas: < 50x103/mm3 (n=7); entre 50-100x103/mm3 (n=7); > 100x103/mm3 (n=7). Como grupo...


Immune thrombocytopenic (ITP) is an immune-mediated acquired disease of adults and children characterized by transient or persistent decrease of the platelet count and, depending upon the degree of thrombocytopenia, increased risk of bleeding. ITP usually presents with clinical manifestations only in platelet counts below 50x103/mm3, and counts between 100 and 150x103/mm3 if they have been stable for more than 6 months do not necessarily indicate a pathologic condition. It has been suggested the existence of different pathophysiological processes involving platelets according to the severity of thrombocytopenia, and that alterations in the megakaryopoiesis and reduced platelet lifespan play a key role in ITP. The flow cytometric analysis of reticulated platelets is useful for evaluating thrombocytopenia that reflect the activity megakaryopoiesis, platelets destruction, plataelet count, and age. Platelets and megakaryocytes contain intrinsic pathway of apoptosis. The activity of key mediators of intrinsic apoptosis, Bak and Bax, is tightly controlled by anti-apoptotic Bcl-2 family members, of which Bcl-xL, wich have been shown to coordinately regulate platelet survival. ITP patients have a larger amount of activated platelets that express P-selectin as well as an increase of platelets-derived microparticles (PMP). We suggest a relationship between platelet production and Bcl-xL and Bax expression in ITP patients from different degrees of thrombocytopenia, that has relate with platelet activation and PMP. Our aim was assessment of ratio between platelets production and apoptosis, and it associate with platelets activation and PMP in differents thrombocytopenia degree in ITP. Patients were considered eligible for the study if they were on regular follow-up at the clinic of haemorrhagic and thrombotic diseases of the Hematology Service of Clinics Hospital of University of São Paulo Medicine School diagnosed with primary immune thrombocytopenia, "idiopathic"....


Assuntos
Apoptose , Plaquetas , Micropartículas Derivadas de Células , Ativação Plaquetária , Púrpura Trombocitopênica Idiopática
17.
Rev. cuba. farm ; 46(2): 150-161, abr.-jun. 2012.
Artigo em Espanhol | LILACS | ID: lil-628453

RESUMO

Objetivo: incrementar la solubilidad en agua del 2-bromo-5-(2-bromo-2-nitrovinyl)-furano (G1), un ingrediente farmacéuticamente activo sintetizado por el Centro de Bioactivos Químicos de la Universidad Central de Las Villas, con potente acción bactericida y fungicida, mediante la elaboración de macropartículas de dispersiones sólidas utilizando un proceso de secado por atomización. Métodos: se realizó un ensayo preliminar de secado por atomización de la suspensión de G1, compuesta por: 10 g de G1, 1 g de Aerosil (Aerosil®, Degusa, Bélgica), 1 g de laurilsulfato de sodio y 100 mL de agua. La atomización se efectuó en un equipo de laboratorio (Buchi Mini Dryer spray) a 90 ºC. La dispersión sólida obtenida fue caracterizada físico-químicamente mediante difracción de rayos X, granulometría láser por el método de difracción angular, calorimetría diferencial de barrido, microscopia electrónica de barrido y espectrofotometría de absorción infraroja. Resultados: las partículas obtenidas presentaron un pequeño tamaño, forma esférica y un incremento de la cristalinidad del G-1; no se encontraron interacciones entre los componentes de la dispersión ni presencia de productos de degradación, y la solubilidad del G-1 en agua resultó notablemente incrementada. Conclusiones: el producto obtenido por la técnica de secado por atomización incrementó apreciablemente la solubilidad del G1 sin afectar los grupos funcionales, responsables de la actividad terapéutica que se le reportan al ingrediente activo estudiado. Estos alentadores resultados sugieren la necesidad de continuar estudios para la optimización del proceso y realizar al producto obtenido ensayos de estabilidad con el objetivo de su futura inclusión en formas farmacéuticas de dosificación.


Objective: to increase the solubility of 2-bromium-5(2-bromium-2-nitrovinyl)-furane (G1), one pharmaceutically active ingredient with potent bactericidal and fungicidal action, synthesized through the preparation of solid dispersion macroparticles based on spray-drying process in the Center of Chemical Bioactives of the Central University in Las Villas province. Methods: a preliminary spray-drying test of GI suspension made up of 10 g of G1, 1g of Aerosil (Aerosil®, Degusa, Bélgica), 1g of sodium laurylsulphate and 100 ml of water was made. A piece of lab equipment known as Buchi Mini Dryer spray served for the spraying at 90 ºC. The solid dispersion was characterized from the physical and chemical viewpoints through X-ray diffraction, laser granulometry based on angular diffraction method, differential scanning calorimetry, electronic scanning microscopy and infrared spectrophotometry. Results: the obtained particles were small, spherical and had increased G1 crystallinity. No interactions were found in the dispersion components; there were no degradation products, and G1 solubility was significantly increased. Conclusions: the product obtained from spray-drying technique substantially raised the solubility of G1 without affecting the functional groups, which are responsible for the reported therapeutic action of the studied active ingredient. These encouraging results endorse the need for further studies to optimizing the process and carrying out stability tests for the product to be included in the pharmaceutical forms of dosing in the future.


Assuntos
Dissolução , Furanos , Farmacocinética , Solubilidade
18.
Rev. cuba. farm ; 46(2)abr.-jun. 2012.
Artigo em Espanhol | CUMED | ID: cum-51188

RESUMO

Objetivo: incrementar la solubilidad en agua del 2-bromo-5-(2-bromo-2-nitrovinyl)-furano (G1), un ingrediente farmacéuticamente activo sintetizado por el Centro de Bioactivos Químicos de la Universidad Central de Las Villas, con potente acción bactericida y fungicida, mediante la elaboración de macropartículas de dispersiones sólidas utilizando un proceso de secado por atomización. Métodos: se realizó un ensayo preliminar de secado por atomización de la suspensión de G1, compuesta por: 10 g de G1, 1 g de Aerosil (Aerosil®, Degusa, Bélgica), 1 g de laurilsulfato de sodio y 100 mL de agua. La atomización se efectuó en un equipo de laboratorio (Buchi Mini Dryer spray) a 90 ºC. La dispersión sólida obtenida fue caracterizada físico-químicamente mediante difracción de rayos X, granulometría láser por el método de difracción angular, calorimetría diferencial de barrido, microscopia electrónica de barrido y espectrofotometría de absorción infraroja. Resultados: las partículas obtenidas presentaron un pequeño tamaño, forma esférica y un incremento de la cristalinidad del G-1; no se encontraron interacciones entre los componentes de la dispersión ni presencia de productos de degradación, y la solubilidad del G-1 en agua resultó notablemente incrementada. Conclusiones: el producto obtenido por la técnica de secado por atomización incrementó apreciablemente la solubilidad del G1 sin afectar los grupos funcionales, responsables de la actividad terapéutica que se le reportan al ingrediente activo estudiado. Estos alentadores resultados sugieren la necesidad de continuar estudios para la optimización del proceso y realizar al producto obtenido ensayos de estabilidad con el objetivo de su futura inclusión en formas farmacéuticas de dosificación.(AU)


Objective: to increase the solubility of 2-bromium-5(2-bromium-2-nitrovinyl)-furane (G1), one pharmaceutically active ingredient with potent bactericidal and fungicidal action, synthesized through the preparation of solid dispersion macroparticles based on spray-drying process in the Center of Chemical Bioactives of the Central University in Las Villas province. Methods: a preliminary spray-drying test of GI suspension made up of 10 g of G1, 1g of Aerosil (Aerosil®, Degusa, Bélgica), 1g of sodium laurylsulphate and 100 ml of water was made. A piece of lab equipment known as Buchi Mini Dryer spray served for the spraying at 90 ºC. The solid dispersion was characterized from the physical and chemical viewpoints through X-ray diffraction, laser granulometry based on angular diffraction method, differential scanning calorimetry, electronic scanning microscopy and infrared spectrophotometry. Results: the obtained particles were small, spherical and had increased G1 crystallinity. No interactions were found in the dispersion components; there were no degradation products, and G1 solubility was significantly increased. Conclusions: the product obtained from spray-drying technique substantially raised the solubility of G1 without affecting the functional groups, which are responsible for the reported therapeutic action of the studied active ingredient. These encouraging results endorse the need for further studies to optimizing the process and carrying out stability tests for the product to be included in the pharmaceutical forms of dosing in the future.(AU)


Assuntos
Furanos , Dissolução , Solubilidade
19.
Rev. colomb. reumatol ; 19(1): 52-58, ene.-mar. 2012.
Artigo em Espanhol | LILACS | ID: lil-639951

RESUMO

El lupus eritematoso sistémico (LES) es una enfermedad caracterizada por la pérdida de la tolerancia hacia antígenos propios que conlleva a la aparición de autoanticuerpos contra antígenos nucleares y daño de órganos asociado. Durante la apoptosis se expone al sistema inmune a múltiples antígenos nucleares y se piensa que alteraciones en la remoción de cuerpos apoptóticos pueden iniciar o perpetuar una respuesta autoinmune. Otra fuente de material nuclear expuesto al medio extracelular son las denominadas micropartículas, las cuales son liberadas de diferentes células no solo durante la apoptosis sino también durante la activación celular o el estrés mecánico. Se ha demostrado que los pacientes con LES presentan autoanticuerpos varios años antes de la fase clínica de la enfermedad, y esta aparición de autoanticuerpos tiende a seguir un curso predecible, con acumulación progresiva de autoanticuerpos específicos. Esta aparición consistentemente ordenada de autoanticuerpos, precediendo por varios años la aparición de la enfermedad clínica, apoya fuertemente las teorías de diseminación de epítopes en LES humano. Varios modelos múridos han tratado de reproducir la enfermedad humana utilizando cuerpos apoptóticos pero sin resultados contundentes. Un reciente modelo animal logra reproducir más fielmente la secuencia de autoanticuerpos y las manifestaciones clínicas del LES al utilizar a la β2GP-I como inmunógeno potenciado por una respuesta de célula T inducida por lipopolisacárido. Las micropartículas, rodeadas de fosfatidilserina y cargadas de material nuclear incluyendo DNA extracelular antigénicamente activo, son asimismo candidatas ideales para servir de plataforma para la diseminación de epítopes en un medio inflamatorio, con la posterior aparición secuencial de autoanticuerpos específicos patogénicos.


Systemic lupus erythematosus (SLE) is a disease characterized by loss of tolerance to self-antigens leading to the development of autoantibodies against nuclear antigens and organ damage. During apoptosis, immune system is exposed to multiple nuclear antigens and is thought that alterations in the removal of apoptotic bodies could start or perpetuate an autoimmune response. Another source of nuclear material exposed to extracellular medium are called microparticles, which are released from various cells not only during apoptosis but also during cell activation or mechanical stress. It has been shown that patients with SLE already have autoantibodies several years before clinical phase of disease, and this appearance of autoantibodies tends to follow a predictable course, with progressive accumulation of specific autoantibodies. This steadily orderly appearance of autoantibodies preceding for several years the onset of clinical disease strongly supports theories of spreading epitopes in human SLE. Several mouse models have tried to replicate the human disease using apoptotic bodies but without conclusive results. A recent animal model can reproduce more closely the sequence of autoantibodies and clinical manifestations of SLE using the β2-glycoprotein I (β2GP-I) as an immunogen powered by a lipopolysaccharide induced T cell response. Microparticles, surrouded by phosphatidylserie and nuclear material loaded including antigenically active extracellular DNA, are also ideal candidates to serve as a.


Assuntos
Humanos , Apoptose , Autoanticorpos , Glicoproteínas , Autoimunidade , Disseminação de Informação , Lúpus Eritematoso Sistêmico , Epitopos
20.
Braz. j. pharm. sci ; 48(4): 699-709, Oct.-Dec. 2012. ilus, tab
Artigo em Inglês | LILACS | ID: lil-665867

RESUMO

The efficacy of a drug in a specific application requires the maintenance of appropriate drug blood level concentration during a prolonged period of time. Controlled release delivery is available for many routes of administration and offers many advantages (as microparticles and nanoparticles) over immediate release delivery. These advantages include reduced dosing frequency, better therapeutic control, fewer side effects, and, consequently, these dosage forms are well accepted by patients. Advances in polymer material science, particle engineering design, manufacture, and nanotechnology have led the way to the introduction of several marketed controlled release products and several more are in pre-clinical and clinical development. The objective of this work is to prepare and evaluate diltiazem HCl loaded albumin microparticles using a factorial design. Albumin (natural polymer) microparticles were prepared by emulsion heat-stabilization method. Selected formulations were characterized for their entrapment efficiency, particle size, surface morphology, and release behavior. Analysis of variance for entrapment efficiency indicates that entrapment efficiency is best fitted to a response surface linear model. Surface morphology was studied by scanning electron microscopy. Scanning electron microscopy of the microparticles revealed a spherical, nonporous and uniform appearance, with a smooth surface. The geometric mean diameter of the microparticles was found to be 2-9 µm, which more than 75% were below 3.5 µm and drug incorporation efficiency of 59.74 to 72.48% (w/w). In vitro release profile for formulations containing diltiazem HCl loaded BSA microparticles with heat stabilization technique shows slow controlled the release of the drug up to 24 hours. The release pattern was biphasic, characterized by an initial burst effect followed by a slow release. All selected microparticles exhibited a prolonged release for almost 24 hours. On comparing regression-coefficient (r²) values for Hixson Crowel, Higuchi and Peppas kinetic models, different batches of microparticles showed Fickian, non-Fickian, and diffusion kinetics. The release mechanism was regulated by D:P ratio. From the statistical analysis it was observed that as the drug:polymer (D:P) ratio increased, there was a significant increase in the encapsulation efficiency. Based on the particle size, entrapment efficiency and physical appearance, DTM-3 formulations were selected for in vivo release study and stability study. The in vivo result of drug loaded microparticles showed preferential drug targeting to liver followed by lungs, kidneys and spleen. Stability studies showed that maximum drug content and closest in vitro release to initial data were found in the formulation stored at 4 ºC. In present study, diltiazem HCl loaded BSA microparticles were prepared and targeted to various organs to satisfactory level and were found to be stable at 4 ºC.


A eficácia terapêutica de um fármaco depende da manutenção de seu nível plasmático adequado em determinado intervalo de tempo. Nesse sentido, a liberação modificada de fármacos está disponível em muitas vias de administração e oferece muitas vantagens (como micropartículas e nanopartículas) quando comparada às formulações de liberação imediata. Essas vantagens incluem reduzida frequência da dosagem, melhor controle terapêutico e menos efeitos colaterais. Assim sendo, esses produtos apresentam maior aceitação pelos pacientes. Os avanços na ciência dos materiais, na engenharia das partículas, em manufatura e em nanotecnologia permitiram a introdução no mercado de vários produtos de liberação modificada e vários outros se encontram em desenvolvimento pré-clínico e clínico. O objetivo do presente trabalho foi preparar e avaliar o fármaco cloridrato de diltiazem associado a micropartículas de albumina utilizando planejamento fatorial. As micropartículas de albumina, um polímero natural, foram preparadas por método de emulsão empregando estabilização por calor. As formulações selecionadas foram caracterizadas no que se refere à sua eficiência de encapsulamento, tamanho médio de partículas, morfologia de superfície e perfil de liberação do fármaco. A análise de variância relativa à eficiência de encapsulamento indicou superfície de resposta linear. Com referência à morfologia superficial, essa foi avaliada empregando microscopia eletrônica de varredura. Essa análise revelou micropartículas esféricas, não porosas e de aparência uniforme, com superfície lisa. O diâmetro médio das micropartículas foi entre 2 e 9 µm, sendo que mais de 75% das micropartículas se apresentaram abaixo de 3,5 µm. Além disso, a eficiência de encapsulamento foi entre 59,74 e 72,48%. Quanto ao ensaio para avaliação do perfil de liberação in vitro do fármaco associado às micropartículas, as formulações apresentaram liberação lenta até 24 horas. O comportamento foi caracterizado por liberação inicial (efeito burst) seguida por liberação lenta. Todas as fórmulas selecionadas apresentaram liberação prolongada por aproximadamente 24 horas. Na comparação entre os valores de coeficientes de regressão (R²), os modelos propostos por Hixson Crowel, Higuchi e Peppas, para diferentes formulações de micropartículas, demonstraram cinética de liberação de acordo com modelo Fickiano e não-Fickiano. O mecanismo de liberação do fármaco foi regulado pela razão entre o fármaco e o polímero. A análise estatística revelou significativo aumento da eficiência de encapsulamento quando essa razão aumentou. As avaliações relativas à análise dimensional das micropartículas, à eficiência de encapsulamento do fármaco e à morfologia permitiram a seleção da formulação DTM-3 para os ensaios de liberação in vivo e para o estudo da estabilidade. O ensaio de liberação in vivo do fármaco associado às micropartículas demonstrou sítio-alvo preferencial no fígado, seguido pelos pulmões rins e baço. No presente estudo, as micropartículas de albumina contendo cloridrato de diltiazem foram adequadamente preparadas e orientadas satisfatoriamente para vários órgãos. Além disso, a formulação selecionada apresentou estabilidade físico-química a 4 ºC.


Assuntos
Diltiazem/análise , Liberação Controlada de Fármacos , Cinética , Albuminas/farmacocinética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...