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1.
Nat Commun ; 14(1): 1602, 2023 03 23.
Artículo en Inglés | MEDLINE | ID: mdl-36959177

RESUMEN

Interactions between cells and the extracellular matrix, mediated by integrin adhesion complexes, play key roles in fundamental cellular processes, including the sensing and transduction of mechanical cues. Here, we investigate systems-level changes in the integrin adhesome in patient-derived cutaneous squamous cell carcinoma cells and identify the actin regulatory protein Mena as a key node in the adhesion complex network. Mena is connected within a subnetwork of actin-binding proteins to the LINC complex component nesprin-2, with which it interacts and co-localises at the nuclear envelope. Moreover, Mena potentiates the interactions of nesprin-2 with the actin cytoskeleton and the nuclear lamina. CRISPR-mediated Mena depletion causes altered nuclear morphology, reduces tyrosine phosphorylation of the nuclear membrane protein emerin and downregulates expression of the immunomodulatory gene PTX3 via the recruitment of its enhancer to the nuclear periphery. We uncover an unexpected role for Mena at the nuclear membrane, where it controls nuclear architecture, chromatin repositioning and gene expression. Our findings identify an adhesion protein that regulates gene transcription via direct signalling across the nuclear envelope.


Asunto(s)
Carcinoma de Células Escamosas , Neoplasias Cutáneas , Humanos , Actinas/genética , Actinas/metabolismo , Carcinoma de Células Escamosas/metabolismo , Núcleo Celular/metabolismo , Expresión Génica , Integrinas/metabolismo , Proteínas de Microfilamentos/metabolismo , Membrana Nuclear/metabolismo , Lámina Nuclear/metabolismo , Neoplasias Cutáneas/metabolismo
2.
Nat Cell Biol ; 25(3): 481-492, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36690849

RESUMEN

Cell proliferation is fundamental for almost all stages of development and differentiation that require an increase in cell number. Although cell cycle phase has been associated with differentiation, the actual process of proliferation has not been considered as having a specific role. Here we exploit human embryonic stem cell-derived endodermal progenitors that we find are an in vitro model for the ventral foregut. These cells exhibit expansion-dependent increases in differentiation efficiency to pancreatic progenitors that are linked to organ-specific enhancer priming at the level of chromatin accessibility and the decommissioning of lineage-inappropriate enhancers. Our findings suggest that cell proliferation in embryonic development is about more than tissue expansion; it is required to ensure equilibration of gene regulatory networks allowing cells to become primed for future differentiation. Expansion of lineage-specific intermediates may therefore be an important step in achieving high-fidelity in vitro differentiation.


Asunto(s)
Cromatina , Páncreas , Humanos , Linaje de la Célula/genética , Diferenciación Celular/genética , Cromatina/genética , Cromatina/metabolismo , Páncreas/metabolismo , Elementos de Facilitación Genéticos/genética
3.
Nat Struct Mol Biol ; 29(9): 891-897, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-36097291

RESUMEN

The regulatory landscapes of developmental genes in mammals can be complex, with enhancers spread over many hundreds of kilobases. It has been suggested that three-dimensional genome organization, particularly topologically associating domains formed by cohesin-mediated loop extrusion, is important for enhancers to act over such large genomic distances. By coupling acute protein degradation with synthetic activation by targeted transcription factor recruitment, here we show that cohesin, but not CTCF, is required for activation of the target gene Shh by distant enhancers in mouse embryonic stem cells. Cohesin is not required for activation directly at the promoter or by an enhancer located closer to the Shh gene. Our findings support the hypothesis that chromatin compaction via cohesin-mediated loop extrusion allows for genes to be activated by enhancers that are located many hundreds of kilobases away in the linear genome and suggests that cohesin is dispensable for enhancers located more proximally.


Asunto(s)
Proteínas de Ciclo Celular , Proteínas Cromosómicas no Histona , Animales , Factor de Unión a CCCTC/genética , Factor de Unión a CCCTC/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Cromatina/genética , Proteínas Cromosómicas no Histona/genética , Proteínas Cromosómicas no Histona/metabolismo , Elementos de Facilitación Genéticos/genética , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , Mamíferos/genética , Ratones , Factores de Transcripción/metabolismo , Cohesinas
4.
Genome Res ; 31(11): 1994-2007, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34417209

RESUMEN

Mutation in the germline is the ultimate source of genetic variation, but little is known about the influence of germline chromatin structure on mutational processes. Using ATAC-seq, we profile the open chromatin landscape of human spermatogonia, the most proliferative cell type of the germline, identifying transcription factor binding sites (TFBSs) and PRDM9 binding sites, a subset of which will initiate meiotic recombination. We observe an increase in rare structural variant (SV) breakpoints at PRDM9-bound sites, implicating meiotic recombination in the generation of structural variation. Many germline TFBSs, such as NRF1, are also associated with increased rates of SV breakpoints, apparently independent of recombination. Singleton short insertions (≥5 bp) are highly enriched at TFBSs, particularly at sites bound by testis active TFs, and their rates correlate with those of structural variant breakpoints. Short insertions often duplicate the TFBS motif, leading to clustering of motif sites near regulatory regions in this male-driven evolutionary process. Increased mutation loads at germline TFBSs disproportionately affect neural enhancers with activity in spermatogonia, potentially altering neurodevelopmental regulatory architecture. Local chromatin structure in spermatogonia is thus pervasive in shaping both evolution and disease.


Asunto(s)
Genoma Humano , Espermatogonias , Sitios de Unión , Secuenciación de Inmunoprecipitación de Cromatina , N-Metiltransferasa de Histona-Lisina/genética , Humanos , Masculino , Mutación , Espermatogonias/metabolismo
5.
Curr Drug Res Rev ; 13(1): 59-72, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-32787770

RESUMEN

BACKGROUND/OBJECTIVE: To study the therapeutic potential of Antileukotriene drug- Camellia sinensis extract co-formulation on histamine induced asthma in guinea pigs. METHODS: SRSD of Montelukast sodium was prepared by the solvent evaporation method. Lyophilized aqueous extract of Camellia sinensis leaves and SRSD mixture was filled in capsule and the capsule shell was coated to achieve initial release lag time. In vitro and pharmacokinetic study of capsules was performed and compared with commercial tablets. A further role of green tea, as an antioxidant adjunct for asthma management, has been analyzed by lung histology, mast cell count and oxidative stress assay in the serum of control and experimental animals. RESULTS: The drug release from the commercial tablet was immediate and rapid, but capsule has shown an initial 3.5 hr lag time followed by sustained action up to 8 hr. Pharmacokinetic results show that studied formulations are bioequivalent with respect to Cmax and AUC, while rest parameters showed asignificant difference. Mast cells count in lung tissue were increased (p<0.001) in the experimental group along with glycoprotein deposition in asthmatic bronchioles. Levels of SOD and GPX were decreased (p<0.05) while CAT was increased (p<0.04) in the asthma group in comparison to control. CONCLUSION: In the experimental animal model, co-formulation was effective in modulating allergic inflammation and contributing to better control of the inflammatory response. Our findings suggest that Camellia sinensis leaves extract may be used as an adjunct for future improvements in asthma treatment and prevention.


Asunto(s)
Asma/tratamiento farmacológico , Camellia sinensis/química , Antagonistas de Leucotrieno/farmacología , Extractos Vegetales/farmacología , Animales , Antiasmáticos/aislamiento & purificación , Antiasmáticos/farmacocinética , Antiasmáticos/farmacología , Antioxidantes/aislamiento & purificación , Antioxidantes/farmacocinética , Antioxidantes/farmacología , Área Bajo la Curva , Preparaciones de Acción Retardada , Modelos Animales de Enfermedad , Liberación de Fármacos , Cobayas , Histamina/inmunología , Inflamación/tratamiento farmacológico , Inflamación/patología , Antagonistas de Leucotrieno/aislamiento & purificación , Antagonistas de Leucotrieno/farmacocinética , Masculino , Mastocitos/metabolismo , Estrés Oxidativo/efectos de los fármacos , Extractos Vegetales/farmacocinética , Hojas de la Planta
6.
Commun Biol ; 3(1): 762, 2020 12 11.
Artículo en Inglés | MEDLINE | ID: mdl-33311554

RESUMEN

Corneal resistance factor (CRF) is altered during corneal diseases progression. Genome-wide-association studies (GWAS) indicated potential CRF and disease genetics overlap. Here, we characterise 135 CRF loci following GWAS in 76029 UK Biobank participants. Enrichment of extra-cellular matrix gene-sets, genetic correlation with corneal thickness (70% (SE = 5%)), reported keratoconus risk variants at 13 loci, all support relevance to corneal stroma biology. Fine-mapping identifies a subset of 55 highly likely causal variants, 91% of which are non-coding. Genomic features enrichments, using all associated variants, also indicate prominent regulatory causal role. We newly established open chromatin landscapes in two widely-used human cornea immortalised cell lines using ATAC-seq. Variants associated with CRF were significantly enriched in regulatory regions from the corneal stroma-derived cell line and enrichment increases to over 5 fold for variants prioritised by fine-mapping-including at GAS7, SMAD3 and COL6A1 loci. Our analysis generates many hypotheses for future functional validation of aetiological mechanisms.


Asunto(s)
Mapeo Cromosómico , Regulación de la Expresión Génica , Sitios de Carácter Cuantitativo , Alelos , Biología Computacional/métodos , Enfermedades de la Córnea/etiología , Enfermedades de la Córnea/metabolismo , Enfermedades de la Córnea/patología , Bases de Datos Genéticas , Femenino , Predisposición Genética a la Enfermedad , Estudio de Asociación del Genoma Completo , Humanos , Masculino , Anotación de Secuencia Molecular , Especificidad de Órganos , Polimorfismo de Nucleótido Simple , Reino Unido
7.
J Biosci ; 452020.
Artículo en Inglés | MEDLINE | ID: mdl-31965996

RESUMEN

The mammalian genome is complex and presents a dynamic structural organization that reflects function. Organization of the genome inside the mammalian nucleus impacts all nuclear processes including but not limited to transcription, replication and repair, and in many biological contexts such as early development, differentiation and physiological adaptations. However, there is limited understating of how 3D organization of the mammalian genome regulates different nuclear processes. Recent advances in microscopy and a myriad of genomics methods -- ropelled by next-generation sequencing -- have advanced our knowledge of genome organization to a great extent. In this review, we discuss nuclear compartments in general and recent advances in the understanding of how mammalian genome is organized in these compartments with an emphasis on dynamics at the nuclear periphery.


Asunto(s)
Núcleo Celular/ultraestructura , Cromatina/ultraestructura , Genoma/genética , Genómica , Animales , Núcleo Celular/genética , Cromatina/genética , Humanos , Mamíferos/genética
8.
Recent Pat Drug Deliv Formul ; 12(4): 267-276, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30539707

RESUMEN

AIM AND BACKGROUND: The rationale of this study is that, treatment of asthmatic Guinea pig with combined administration of Montelukast sodium and Green Tea Extract (GTE) as a single capsule will mitigate the inflammatory injury in the airways and weaken the asthmatic response. Recent patents for the treatment of asthma researched a polyphenolic alternatives for antiasthmatic combination therapy, especially for those patients who remains unresponsive or poorly responsive for current asthma therapy (US7232585B2). Synergistic activity of green tea polyphenols and therapeutic, prophylatic agents are also reported in some recent patents (US20120172423A1, US20150320696A1). The present work is therefore aimed, to study the effect of Montelukast Sodium capsules coformulated with GTE on oxidative stress markers including Malondialdehyde (MDA), Glutathione (GSH) in different organs and Oxygen Radical Absorbance Capacity (ORAC) assay in plasma. MATERIALS AND METHODS: Guinea pigs were placed in histamine chamber and exposed to an aerosol challenge of 0.2% w/v histamine dihydrochloride in distilled water using pressurized air driven nebulizer at a pressure of 0.05 MPa-0.106 MPa for one week. After that, they were divided in to four groups of three each; control, asthmatic control, asthmatic treated with marketed preparation and asthmatic received developed capsules. After oral administration of formulations for three days, pigs were scarificed and oxidative stress markers level including cytoarchitectural manifestation in tissues was studied. RESULTS: In comparison with the healthy control group, MDA level of the asthmatic animal liver and lung was found to be elevated as 0.059 ± 0.031(p < 0.002) and 0.802 ± 0.310 (p < 0.005) respectively, whereas GSH level was declined as 13.223 ± 1.485 (p < 0.0001) in liver and 3.037 ± 0.282 (p < 0.0004) in lung tissues. TAC of asthmatic animal plasma was low as 2.132 ± 0.986 mM Trolox Eq/L (p < 0.009). The level of these biomarkers reverts back towards normal after treatment with marketed and developed formulation, although treatment with developed formulation was more efficacious since it was coformulated with GTE, which acts as an adjuvant for the management of inflammatory disease like asthma. CONCLUSION: It is contemplated that, use of GTE as an adjuvant to anti leukotriene drug played a significant role in asthma management by reducing oxidant injury. Since, studies in animals do not directly translate to human biology, further multi-control studies with better sampled patient population and more number of patients are needed.


Asunto(s)
Acetatos/uso terapéutico , Asma/tratamiento farmacológico , Estrés Oxidativo/efectos de los fármacos , Extractos Vegetales/uso terapéutico , Quinolinas/uso terapéutico , Té/química , Acetatos/administración & dosificación , Administración Oral , Animales , Antiasmáticos/administración & dosificación , Antiasmáticos/uso terapéutico , Asma/inducido químicamente , Enfermedad Crónica/tratamiento farmacológico , Ciclopropanos , Combinación de Medicamentos , Femenino , Glutatión/metabolismo , Cobayas , Histamina , Hígado/metabolismo , Pulmón/metabolismo , Masculino , Malondialdehído/metabolismo , Capacidad de Absorbancia de Radicales de Oxígeno , Patentes como Asunto , Extractos Vegetales/administración & dosificación , Extractos Vegetales/química , Quinolinas/administración & dosificación , Sulfuros
9.
Recent Pat Drug Deliv Formul ; 12(3): 199-211, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30345934

RESUMEN

PURPOSE: The purpose of the study was formulation development, optimization and evaluation of a Self-Emulsifying Drug Delivery System (SEDDS) of Simvastatin (SIM) for improvement in dissolution and bioavailability of SIM. Solubility enhancement of Biopharmaceutical Classification System (BCS) Class-II drugs is a burning topic and attracting various publications and patents regarding different strategies employed for improvement of dissolution viz., USOO5340591A (Solid dispersion), US005472954A, US005646131A (complexation), USOO5858410A (Nanosuspensions), USOO5874029A (micronization) US2008.00095O2A1 (Solid composites), US2008O146640A1 (Prodrug) US 2009001 1009 A1 (nanocapsules), etc. Methods: SEDDS was prepared on the basis of solubility studies employing Capmul MCM EP as lipid and Cremophor ELP as surfactant. Box-Behnken design was implemented for optimization by using lipid concentration, surfactant concentration and mixing time as dependent variables and their impact was observed on particle size, poly dispersity index (PDI) and drug released in 15min. Optimized formulation was evaluated for particle size, PDI, zeta potential, emulsification time, transmittance, invitro drug release and in situ Single-Pass Intestinal Perfusion (SPIP) studies. RESULTS: For optimized formulation, OF1 value of particle size, PDI, zeta potential, emulsification time, transmittance and percent in-vitro release were 162±14.32nm, 0.19±0.01, -22.3 ±1.1mV, 93±3.11 sec, 99.45±4.35 % and 99.43± 5.6 % in 30 min respectively. In-situ SPIP studies were performed on Wistar rats and the value of predicted fraction absorbed for humans was found to be 0.98. CONCLUSION: SIM SEDDS was successfully developed and evaluated for in-vitro & in-vivo parameters. All the evaluated parameters were in tolerable limits. In vitro release studies from optimized formulation, OF1, exhibited maximum drug release when compared to SIM API and marketed preparation. Moreover, the predicted value of fraction absorbed (Fa) in humans by in-situ SPIP method was also in agreement with in-vitro dissolution studies thus, confirming SEDDS as a suitable drug delivery system for solubility enhancement of SIM.


Asunto(s)
Composición de Medicamentos , Sistemas de Liberación de Medicamentos/métodos , Mucosa Intestinal/metabolismo , Simvastatina/administración & dosificación , Simvastatina/farmacocinética , Animales , Disponibilidad Biológica , Diglicéridos/química , Liberación de Fármacos , Emulsionantes , Emulsiones , Femenino , Masculino , Monoglicéridos/química , Tamaño de la Partícula , Patentes como Asunto , Polietilenglicoles/química , Ratas , Simvastatina/química , Solubilidad , Propiedades de Superficie , Tensoactivos
10.
Genome Biol ; 18(1): 242, 2017 12 28.
Artículo en Inglés | MEDLINE | ID: mdl-29284524

RESUMEN

BACKGROUND: Enhancers are modular regulatory elements that are central to the spatial and temporal regulation of gene expression. Bidirectional transcription initiating at enhancers has been proposed to mark active enhancers and as such has been utilized to experimentally identify active enhancers de novo. RESULTS: Here, we show that bidirectional transcription initiation is a pervasive feature of accessible chromatin, including at enhancers, promoters, and other DNase hypersensitive regions not marked with canonical histone modification profiles. Transcription is less predictive for enhancer activity than epigenetic modifications such as H3K4me1 or the accessibility of DNA when measured both in enhancer assays and at endogenous loci. The stability of enhancer initiated transcripts does not influence measures of enhancer activity and we cannot detect evidence of purifying selection on the resulting enhancer RNAs within the human population. CONCLUSIONS: Our results indicate that bidirectional transcription initiation from accessible chromatin is not sufficient for, nor specific to, enhancer activity. Transcription initiating at enhancers may be a frequent by-product of promiscuous RNA polymerase initiation at accessible chromatin and is unlikely to generally play a functional role in enhancer activity.


Asunto(s)
Cromatina/genética , Elementos de Facilitación Genéticos , Iniciación de la Transcripción Genética , Línea Celular , Ensamble y Desensamble de Cromatina/genética , ARN Polimerasas Dirigidas por ADN/metabolismo , Desoxirribonucleasas/metabolismo , Regulación de la Expresión Génica , Histonas/metabolismo , Humanos , Modelos Biológicos , Estabilidad del ARN , Transcripción Genética
11.
Nat Genet ; 48(6): 681-6, 2016 06.
Artículo en Inglés | MEDLINE | ID: mdl-27089178

RESUMEN

Histone acetylation is generally associated with active chromatin, but most studies have focused on the acetylation of histone tails. Various histone H3 and H4 tail acetylations mark the promoters of active genes. These modifications include acetylation of histone H3 at lysine 27 (H3K27ac), which blocks Polycomb-mediated trimethylation of H3K27 (H3K27me3). H3K27ac is also widely used to identify active enhancers, and the assumption has been that profiling H3K27ac is a comprehensive way of cataloguing the set of active enhancers in mammalian cell types. Here we show that acetylation of lysine residues in the globular domain of histone H3 (lysine 64 (H3K64ac) and lysine 122 (H3K122ac)) marks active gene promoters and also a subset of active enhancers. Moreover, we find a new class of active functional enhancers that is marked by H3K122ac but lacks H3K27ac. This work suggests that, to identify enhancers, a more comprehensive analysis of histone acetylation is required than has previously been considered.


Asunto(s)
Elementos de Facilitación Genéticos , Histonas/metabolismo , Acetilación , Inmunoprecipitación de Cromatina , Células Madre Embrionarias/citología , Regulación de la Expresión Génica , Histonas/química , Humanos , Células K562 , Lisina/metabolismo
12.
Pharm Dev Technol ; 19(1): 48-54, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23281714

RESUMEN

CONTEXT: Transdermal formulations contain permeation enhancer which causes skin damage. Ceramide 2 is natural lipid found in stratum corneum (SC). OBJECTIVE: Drug-loaded nanovesicles of ceramide-2, cholesterol, palmitic acid, cholesteryl sulfate were formulated and analyzed for physical and biological properties. Diclofenac was used as a model drug. MATERIALS AND METHOD: The vesicles were prepared using the film hydration method and characterized for physical parameters, in vitro drug release, accelerated stability studies and formulated into gel. Respective gels were compared with a commercial formulation (CEG) and plain carbopol gel (CG) containing drug for ex vivo, in vivo drug permeation and anti-inflammatory activity. RESULTS: The vesicles were stable with optimum physical parameters. DCG-1 showed 92.89% in vitro drug release. Ceramide vesicles showed drug release between 18 and 25 µg/cm(2) whereas CG and CEG released 0.33 and 1.35 µg/cm(2) drug, respectively. DCG-1 and CEG showed corresponding Cmax at 6 and 4 h, respectively. DCG-1 showed six times AUC than CEG. DCG-1 inhibited edema by 86.37% by 4th hour of application. DISCUSSION: The presence of ceramide 2 specifically promotes the drug permeation through SC and dermis and also contribute towards stability and non-irritancy. CONCLUSION: The composition of the nanovesicle played an important role in physical properties and drug permeation.


Asunto(s)
Antiinflamatorios no Esteroideos/administración & dosificación , Ceramidas/química , Diclofenaco/administración & dosificación , Nanocápsulas/química , Absorción Cutánea , Administración Cutánea , Animales , Antiinflamatorios no Esteroideos/farmacocinética , Antiinflamatorios no Esteroideos/farmacología , Colesterol/química , Ésteres del Colesterol/química , Diclofenaco/farmacocinética , Diclofenaco/farmacología , Masculino , Ácido Palmítico/química , Ratas , Ratas Wistar , Piel/efectos de los fármacos , Piel/metabolismo , Pruebas de Irritación de la Piel
13.
Artif Cells Nanomed Biotechnol ; 42(5): 323-30, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23944163

RESUMEN

CONTEXT: Ibuprofen is an important NSAID, however, it can cause GI disturbances when given orally, and employment of transdermal route will require permeation enhancer causing skin injury. OBJECTIVE: Drug-loaded nanovesicles of ceramide-2, cholesterol, palmitic acid, and cholesteryl sulfate (ICVG) were formulated and analyzed for physicochemical and permeation properties. MATERIALS AND METHOD: Vesicles were formulated using film hydration method and physicochemical parameters, in vitro drug release, and stability were assessed. Further, nanovesicle gels were evaluated against plain gel containing drug (CG) for ex vivo/in vivo drug permeation and anti-inflammatory activity. RESULTS: The developed formulations showed optimal physicochemical profile and ICV-1 gave 97.24% drug release. Drug permeation was between 17.32 and 33.12 µg/cm(2) for ICVG formulations and 0.27 µg/cm(2) for CG. ICVG-1 and CG showed Cmax of 9.6 and 0.7 µg/ml at 8 and 4 h. ICVG-1 showed 19.9 times higher AUC than CG. Edema inhibition was 57.98% during initial hours by ICVG-1. DISCUSSION: Ratio of ceramide 2 and palmitic acid plays a critical role in drug permeation through stratum corneum. The stability and protective effect of the formulations were due to ceramide content. CONCLUSION: The composition has an important role in physicochemical properties and drug permeation thereby generating an optimum formulation.


Asunto(s)
Antiinflamatorios no Esteroideos/metabolismo , Antiinflamatorios no Esteroideos/farmacología , Ceramidas/química , Fenómenos Químicos , Ibuprofeno/metabolismo , Ibuprofeno/farmacología , Nanoestructuras/química , Administración Cutánea , Animales , Antiinflamatorios no Esteroideos/administración & dosificación , Antiinflamatorios no Esteroideos/química , Química Farmacéutica , Liberación de Fármacos , Humanos , Ibuprofeno/administración & dosificación , Ibuprofeno/química , Masculino , Membranas Artificiales , Permeabilidad , Ratas , Piel/metabolismo
14.
Artif Cells Nanomed Biotechnol ; 42(5): 296-301, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23865793

RESUMEN

Lipid vesicles are an important drug carrier which can serve for controlled delivery of drugs; however, these vesicles are quite unstable at ambient temperature and require stringent storage condition. Present work was done to develop a stable vesicular system for drug delivery. Vesicles of ceramide-2, cholesterol, cholesterol sulfate, and palmitic acid were prepared and compared with phosphatidylcholine vesicles for physicochemical parameters and accelerated stability. Diclofenac sodium was used as a model drug. Based on physicochemical parameter and in vitro release PCV-3 and CV-3 were selected for further studies in three different accelerated stability conditions. PCV-3 showed moderate changes at 4°C but was severely affected at 25°C and 40°C. CV-3 showed stable characteristics at 4°C and 25°C whereas at 40°C, CV-3 showed signs of slight modification owing to moisture absorption. Based on the study, CV-3 containing highest content of palmitic acid was found to be most stable.


Asunto(s)
Liposomas/química , Nanoestructuras/química , Química Farmacéutica , Diclofenaco/química , Liberación de Fármacos , Estabilidad de Medicamentos , Fosfatidilcolinas/química
15.
Drug Dev Ind Pharm ; 40(4): 568-76, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23547761

RESUMEN

UNLABELLED: Abstract Context: The vesicles based on skin lipid have a drug localization effect and its main lipid, ceramide provides protective and regenerative effects while oleic acid (OA) is a penetration enhancer, however, it causes slight irritation, so we have formulated formulation incorporating both of these to develop a transdermal formulation for better permeation. OBJECTIVE: Present study investigated the preparation and characterization of physicochemical properties and permeation of nanovesicles of ceramide-2 containing OA and palmitic acid (PA) respectively and a commercial gel. MATERIALS AND METHODS: The vesicles were made using ceramide 2, cholesterol (Chol), cholesteryl sulfate (CS) and OA or PA, respectively, using film hydration method. The vesicles were characterized for physicochemical properties, ex vivo permeation using human skin and pharmacokinetic parameters and anti-inflammatory activity in rats. RESULTS: The vesicles showed size at 102-125 nm while PDI was 0.11-0.13 and negative zeta potential. OV-3 showed highest entrapment efficiency. The drug fluxes were 92.02 and 8.920 µg/cm(2)/h, respectively, for OV-3 and PV-1. The Cmax were 7.91 and 4.01 µg/ml at 4 and 6 h for OV-3 (2.5 mg) and PV-1 (10 mg), respectively. OV-3 and PV-1 showed 98.8% and 77.36% edema inhibition, respectively, at 3 h. DISCUSSION: Both formulations showed similar physical parameters and different permeation since OA get incorporated in vesicles and increases its permeability and ceramide makes sure that vesicles can rapidly traverse the stratum corneum. CONCLUSION: OV-3 containing 3% OA showed optimum physical parameters and good permeation with maximum anti-inflammatory activity.


Asunto(s)
Ceramidas/química , Diclofenaco/administración & dosificación , Sistemas de Liberación de Medicamentos , Excipientes/química , Administración Cutánea , Animales , Antiinflamatorios no Esteroideos/administración & dosificación , Antiinflamatorios no Esteroideos/farmacocinética , Antiinflamatorios no Esteroideos/farmacología , Química Farmacéutica/métodos , Diclofenaco/farmacocinética , Diclofenaco/farmacología , Modelos Animales de Enfermedad , Humanos , Inflamación/tratamiento farmacológico , Inflamación/patología , Masculino , Nanopartículas , Ácido Oléico/química , Ácido Palmítico/química , Tamaño de la Partícula , Ratas , Ratas Wistar , Absorción Cutánea
16.
BMC Genomics ; 14: 402, 2013 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-23767421

RESUMEN

BACKGROUND: RNA polymerase (pol) III transcribes a unique class of genes with intra-genic promoters and high transcriptional activity. The major contributors to the pol III transcriptome, tRNAs genes are found scattered on all chromosomes of yeast. A prototype tDNA of <150 bp length, is generally considered nucleosome-free while some pol III-transcribed genes have been shown to have nucleosome-positioning properties. RESULTS: Using high resolution ChIP-chip and ChIP-seq methods, we found several unique features associated with nucleosome profiles on all tRNA genes of budding yeast, not seen on nucleosome-dense counterparts in fission yeast and resting human CD4+ T cells. The nucleosome-free region (NFR) on all but three yeast tDNAs is found bordered by an upstream (US) nucleosome strongly positioned at -140 bp position and a downstream (DS) nucleosome at variable positions with respect to the gene terminator. Perturbation in this nucleosomal arrangement interferes with the tRNA production. Three different chromatin remodelers generate and maintain the NFR by targeting different gene regions. Isw1 localizes to the gene body and makes it nucleosome-depleted, Isw2 maintains periodicity in the upstream nucleosomal array, while RSC targets the downstream nucleosome. Direct communication of pol III with RSC serves as a stress-sensory mechanism for these genes. In its absence, the downstream nucleosome moves towards the gene terminator. Levels of tRNAs from different families are found to vary considerably as different pol III levels are seen even on isogenes within a family. Pol III levels show negative correlation with the nucleosome occupancies on different genes. CONCLUSIONS: Budding yeast tRNA genes maintain an open chromatin structure, which is not due to sequence-directed nucleosome positioning or high transcription activity of genes. Unlike 5' NFR on pol II-transcribed genes, the tDNA NFR, which facilitates tDNA transcription, results from action of chromatin remodeler Isw1, aided by Isw2 and RSC. The RSC-regulated nucleosome dynamics at the 3' gene-end serves as a novel regulatory mechanism for pol III transcription in vivo, probably by controlling terminator-dependent facilitated recycling of pol III. Salient features of yeast tDNA chromatin structure reported in this study can explain the basis of the novel non-transcriptional roles ascribed to tDNAs.


Asunto(s)
Ensamble y Desensamble de Cromatina , Nucleosomas/genética , ARN de Hongos/genética , ARN de Transferencia/genética , Saccharomycetales/genética , Transcripción Genética/genética , Adenosina Trifosfatasas/metabolismo , Humanos , ARN Polimerasa II/metabolismo , ARN Polimerasa III/metabolismo , Saccharomycetales/citología , Saccharomycetales/metabolismo , Factores de Transcripción/metabolismo
17.
Int J Pharm Investig ; 1(1): 10-6, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23071914

RESUMEN

AIM: The aim of the project was to develop cross-linked b-cyclodextrin (CL ß-CD) microparticles for controlled delivery of a highly water-soluble drug. MATERIALS AND METHODS: CL ß-CD microparticles were prepared by emulsification phase separation technique using epichlorohydrin as a cross-linking reagent. The developed microparticles were compared with ß-CD for their pharmacotechnical properties. A highly water-soluble model drug, pravastatin sodium (PS) was loaded within these hydrophobic microparticles by active drug loading method using nonionic surfactant Tween 80 as the loading facilitator. RESULTS: Maximal drug fixation (216.8 mg/g beads) was observed in pH 4 at 20°C. In vitro release studies of PS-loaded CL ß-CD microparticles in simulated gastric fluid and simulated intestinal fluid resulted in modified dissolution profiles. Modeling of release profiles confirmed controlled release (r(2) = 0.9910) of PS from the cross-linked system. CONCLUSION: Controlled release CL ß-CD microparticles PS that have the potential to enhance its therapeutic properties by offering the advantage of less frequent dosing and decreased fluctuations in the blood levels during the dosing interval were successfully developed.

18.
Eur J Med Chem ; 45(11): 4963-7, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20817328

RESUMEN

3D QSAR analysis for the 21 molecules of 1,3,4-oxadiazoles was carried out by using k-Nearest Neighbor Molecular Field Analysis (kNN-MFA) combined with various selection procedures. 30 3D QSAR models were generated; one of these models was selected on the basis of q(2) and pred_r(2) values. The selected Model has training set of 17 molecules and test set of 4 molecules with validation (q(2)) and cross validation (pred_r(2)) values of 0.6969 and 0.6148 respectively. Title compounds of 1,3,4-oxadiazole derivatives were synthesized by the ring closure reactions of various acylhydrazides with carbon disulphide (4a-e) and with aromatic acids in POCl(3) (5a-e). After structural elucidation, all the synthesized compounds were evaluated for their antimicrobial activity against Escherichia coli, Staphylococcus aureus and Staphylococcus epidermidis.


Asunto(s)
Antibacterianos/síntesis química , Antibacterianos/farmacología , Oxadiazoles/síntesis química , Oxadiazoles/farmacología , Antibacterianos/química , Diseño de Fármacos , Espectroscopía de Resonancia Magnética , Pruebas de Sensibilidad Microbiana , Oxadiazoles/química , Relación Estructura-Actividad Cuantitativa , Espectroscopía Infrarroja por Transformada de Fourier , Staphylococcus aureus/efectos de los fármacos , Staphylococcus epidermidis/efectos de los fármacos
19.
Iran J Pharm Res ; 9(4): 411-6, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-24381606

RESUMEN

Brown alga, Turbinariaconoideswas successively extracted with n-hexane, cyclohexane, methanol and ethanol:water (1:1). The extracts were evaluated for antibacterial and antifungal activities by disc diffusion method. Minimal inhibitory concentration was determined for active extracts by broth dilution method. The antiviral activity and cytotoxicity of the extracts were tested in human embryonic lung (HEL) cells (herpes simplex virus-1, herpes simplex virus-2, vaccinia virus, vesicular stomatitis virus and herpes simplex virus-1 TK- KOS ACVr), human epithelial (HeLa) cells (vesicular stomatitis virus and coxsackie virus B4) and Vero cells (parainfluenza-3 virus, reovirus-1, sindbis virus coxsackie virus B4 and puntatoro virus). The results revealed that extracts exhibited cytotoxicity ranged from 20 to >100 µg/mL. Moderate activity was demonstrated by n-hexane and cyclohexane extracts against viruses, whereas methanol and ethanol:water (1:1) extracts were not active. Ethanol:water (1:1) presented neither antibacterial nor antifungal activity against tested organisms. Cyclohexane extract possessed a broad array of antibacterial activity and exhibited remarkable antifungal property. It is noteworthy that minimal inhibitory concentration of cyclohexane extract against Aspergillusnigeris comparable with that of clotrimazole. This potentiality demonstrates that it could be used to treat bacterial and fungal infections.

20.
Acta Pol Pharm ; 66(3): 297-303, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19645330

RESUMEN

A new isoflavone (1) isolated from the roots of Flemingia strobilifera (L) R. Br. was identified as 5,7,4'-trihydroxy 8,2',5'-tri(3-methylbut-2-enyl)isoflavone along with the known phytoconstituents: 5,7,2',4'-tetrahydroxyisoflavone (2), 5,7,4'-trihydroxyisoflavone (3) and beta-sitosterol (4). Structure assignments were performed on the basis of spectroscopic data including homo- and heteronuclear 1D and 2D NMR (COSY, HMBC and DEPT) and MS studies. The compounds were tested in vitro for antimicrobial activity and antioxidant activity and compounds (1-3) proved to be moderately active.


Asunto(s)
Fabaceae/química , Isoflavonas/farmacología , Antibacterianos/aislamiento & purificación , Antibacterianos/farmacología , Antifúngicos/aislamiento & purificación , Antifúngicos/farmacología , Antioxidantes/aislamiento & purificación , Antioxidantes/farmacología , Isoflavonas/aislamiento & purificación , Espectroscopía de Resonancia Magnética/métodos , Pruebas de Sensibilidad Microbiana , Raíces de Plantas
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