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71.
Ioannis Nikolakakis Athanasia Panagopoulou Andrea Salis Stavros Malamataris 《AAPS PharmSciTech》2015,16(1):129-139
Self-emulsifying pellets were prepared using microcrystalline cellulose, emulsions of caprylic/capric triglyceride, and three Cremophors (ELP, RH40, and RH60) at 1.5 and 2.3 weight ratios, and two drugs (furosemide and propranolol) of different lipophilicity. Droplet size, zeta potential (ζ) and viscosity of emulsions, and pellet size, shape, friability, tensile strength, disintegration, and drug migration in pellets were determined. Evaluation of reconstituted emulsions was based on droplet size and ζ. Factorial design and 3-way ANOVA was applied to estimate the significance of the effects of the drug, surfactant and oil/surfactant ratio. It was found that droplet size, viscosity and ζ of emulsions, and size, shape, and friability of pellets were affected by the studied factors and were significant interactions between their effects on pellet size and friability. Migration of drug towards the pellet surface was higher for the less lipophilic furosemide and higher oil content. Linear relationships were found between the emulsion viscosity and the shape parameters of the pellets (for the aspect ratio R2 = 0.796 for furosemide and R2 = 0.885 for propranolol and for the shape factor, eRR2 = 0.740 and R2 = 0.960, respectively). For all the formulations examined, an exponential relationship was found between migration (M%) and the product of viscosity (η) and solubility of drug in oil/surfactant mixture (S) (M% = 98.1e-0.016 [η•S], R2 = 0.856), which may be useful in formulation work.KEY WORDS: drug distribution, emulsion and pellet characterization, friability and tensile strength, furosemide and propranolol, self-emulsifying pellets 相似文献
72.
Storage of poultry meat under modified atmospheres or vacuum packs: possible role of microbial metabolites as indicator of spoilage 总被引:2,自引:1,他引:1
The effect of carbon dioxide (100%), nitrogen (100%), carbon dioxide/oxygen (20% : 80%) or vacuum pack at 3 and 10°C was studied on the microbial flora, in skinless poultry breast fillets or thigh meat. Lactic acid bacteria and Brochothrix thermosphacta were the predominant organisms in samples stored in vacuum packs, carbon dioxide and nitrogen. Pseudomonads grew only in oxygen/carbon dioxide packaging systems. The concentration of lactate diminished in both thigh and breast meat during storage at 3 and 10°C. This decrease was more pronounced in thigh meat stored under 20% : 80% carbon dioxide/oxygen. Acetate increased to varying degrees in all samples regardless of the storage conditions. 相似文献
73.
Metabolism of platelet-activating factor (PAF; 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) and lyso-PAF (1-O-alkyl-2-lyso-sn-glycero-3-phosphocholine) by cultured rat Kupffer cells. 下载免费PDF全文
In platelets, and in several other cell systems, pre-treatment with protein kinase C activators such as phorbol 12-myristate 13-acetate (PMA) results in the inhibition of receptor-mediated responses, suggesting that protein kinase C may play an important role in the termination of signal transduction. In the present study, we have attempted to locate the site of action of phorbol ester by comparing thrombin-induced (i.e. receptor-mediated) platelet activation with that induced by guanosine 5'-[gamma-thio]triphosphate (GTP[S]) and NaF, two agents which by-pass the receptor and initiate platelet responses by directly modulating G-protein function. After a 10 s pre-treatment with PMA (16 nM), dense-granule secretion induced by thrombin (0.2 unit/ml), GTP[S] (40 microM) and NaF (30 mM) was potentiated, resulting in a greater than additive response to agent plus PMA. However, after a 5 min pre-treatment, thrombin-induced secretion alone was inhibited, whereas PMA plus GTP[S]/NaF-induced release remained greater than additive. [32P]Phosphatidate formation in response to all three agents, in contrast, was inhibited by 50-70% in PMA (5 min)-treated platelets. That secretion induced by these agents is a protein kinase C-dependent event was demonstrable by using staurosporine, a protein kinase C inhibitor which at concentrations of 1-10 nM inhibited (70-90%) PMA-induced as well as thrombin- and NaF-induced secretion and protein phosphorylation. In membranes from PMA-treated platelets, thrombin-stimulated GTPase activity was significantly enhanced compared with that in untreated membranes (59% versus 82% increase over basal activity). The results suggest that inhibition of receptor-mediated responses by PMA may be directed towards two sites relating to G-protein activation: (i) receptor-stimulated GTPase activity and (ii) G-protein-phospholipase C coupling. Furthermore, the lack of inhibition of NaF- and GTP[S]-induced secretion by PMA suggests that different mechanisms may be involved in thrombin-induced and G-protein-activator-induced secretion. 相似文献
74.
Pooyan Aliuos Jennifer Schulze Markus Schomaker Günter Reuter Stefan R. O. Stolle Darja Werner Tammo Ripken Thomas Lenarz Athanasia Warnecke 《PloS one》2016,11(2)
Introduction
Long-term drug delivery to the inner ear may be achieved by functionalizing cochlear implant (CI) electrodes with cells providing neuroprotective factors. However, effective strategies in order to coat implant surfaces with cells need to be developed. Our vision is to make benefit of electromagnetic field attracting forces generated by CI electrodes to bind BDNF-secreting cells that are labelled with magnetic beads (MB) onto the electrode surfaces. Thus, the effect of MB-labelling on cell viability and BDNF production were investigated.Materials and Methods
Murine NIH 3T3 fibroblasts—genetically modified to produce BDNF—were labelled with MB.Results
Atomic force and bright field microscopy illustrated the internalization of MB by fibroblasts after 24 h of cultivation. Labelling cells with MB did not expose cytotoxic effects on fibroblasts and allowed adhesion on magnetic surfaces with sufficient BDNF release.Discussion
Our data demonstrate a novel approach for mediating enhanced long-term adhesion of BDNF-secreting fibroblasts on model electrode surfaces for cell-based drug delivery applications in vitro and in vivo. This therapeutic strategy, once transferred to cells suitable for clinical application, may allow the biological modifications of CI surfaces with cells releasing neurotrophic or other factors of interest. 相似文献75.
Changes in DNA methylation patterns is a prominent characteristic of human tumors. Tumor cells display reduced levels of genomic DNA methylation and site-specific CpG island hypermethylation. Methylation of CpG dinucleotides is catalyzed by the enzyme family of DNA methyltransferases (DNMTs). In this review, the role of DNA methylation and DNMTs as key determinants of carcinogenesis is further elucidated. The chromatin modifying proteins that are known to interact with DNMTs are also described. Finally, the role of DNMTs as potential therapeutic targets is addressed. 相似文献
76.
The reprogramming of human somatic cells to induced pluripotent stem (hiPS) cells enables the possibility of generating patient-specific autologous cells for regenerative medicine. A number of human somatic cell types have been reported to generate hiPS cells, including fibroblasts, keratinocytes and peripheral blood cells, with variable reprogramming efficiencies and kinetics. Here, we show that human astrocytes can also be reprogrammed into hiPS (ASThiPS) cells, with similar efficiencies to keratinocytes, which are currently reported to have one of the highest somatic reprogramming efficiencies. ASThiPS lines were indistinguishable from human embryonic stem (ES) cells based on the expression of pluripotent markers and the ability to differentiate into the three embryonic germ layers in vitro by embryoid body generation and in vivo by teratoma formation after injection into immunodeficient mice. Our data demonstrates that a human differentiated neural cell type can be reprogrammed to pluripotency and is consistent with the universality of the somatic reprogramming procedure. 相似文献
77.
Tzika AC Helaers R Van de Peer Y Milinkovitch MC 《Bioinformatics (Oxford, England)》2008,24(2):151-157
MOTIVATION: Practitioners of comparative genomics face huge analytical challenges as whole genome sequences and functional/expression data accumulate. Furthermore, the field would greatly benefit from a better integration of this wealth of data with evolutionary concepts. RESULTS: Here, we present MANTIS, a relational database for the analysis of (i) gains and losses of genes on specific branches of the metazoan phylogeny, (ii) reconstructed genome content of ancestral species and (iii) over- or under-representation of functions/processes and tissue specificity of gained, duplicated and lost genes. MANTIS estimates the most likely positions of gene losses on the true phylogeny using a maximum-likelihood function. A user-friendly interface and an extensive query system allow to investigate questions pertaining to gene identity, phylogenetic mapping and function/expression parameters. AVAILABILITY: MANTIS is freely available at http://www.mantisdb.org and constitutes the missing link between multi-species genome comparisons and functional analyses. 相似文献
78.
Domokos Ger? Petra Szoleczky Athanasia Chatzianastasiou Andreas Papapetropoulos Csaba Szabo 《Molecular medicine (Cambridge, Mass.)》2014,20(1):313-328
Poly(ADP-ribose) polymerase-1 (PARP-1) activation is a hallmark of oxidative stress–induced cellular injury that can lead to energetic failure and necrotic cell death via depleting the cellular nicotinamide adenine dinucleotide (NAD+) and ATP pools. Pharmacological PARP-1 inhibition or genetic PARP-1 deficiency exert protective effects in multiple models of cardiomyocyte injury. However, the connection between nuclear PARP-1 activation and depletion of the cytoplasmic and mitochondrial energy pools is poorly understood. By using cultured rat cardiomyocytes, here we report that ring finger protein 146 (RNF146), a cytoplasmic E3-ubiquitin ligase, acts as a direct interactor of PARP-1. Overexpression of RNF146 exerts protection against oxidant-induced cell death, whereas PARP-1–mediated cellular injury is augmented after RNF146 silencing. RNF146 translocates to the nucleus upon PARP-1 activation, triggering the exit of PARP-1 from the nucleus, followed by rapid degradation of both proteins. PARP-1 and RNF146 degradation occurs in the early phase of myocardial ischemia-reperfusion injury; it precedes the induction of heat shock protein expression. Taken together, PARP-1 release from the nucleus and its rapid degradation represent newly identified steps of the necrotic cell death program induced by oxidative stress. These steps are controlled by the ubiquitin-proteasome pathway protein RNF146. The current results shed new light on the mechanism of necrotic cell death. RNF146 may represent a distinct target for experimental therapeutic intervention of oxidant-mediated cardiac injury. 相似文献
79.
Moutafidi Athanasia Gatzounis George Zolota Vassiliki Assimakopoulou Martha 《Journal of molecular histology》2021,52(6):1233-1244
Journal of Molecular Histology - Novel data report a “cross-talk” between Heat-Shock Factor 1 (HSF1) and the transient receptor potential vanilloid 1 cation channel (TRPV1) located in... 相似文献
80.
Konstantinos Sofiadis Natasa Josipovic Milos Nikolic Yulia Kargapolova Nadine Übelmesser Vassiliki VaramogianniMamatsi Anne Zirkel Ioanna Papadionysiou Gary Loughran James Keane Audrey Michel Eduardo G Gusmao Christian Becker Janine Altmüller Theodore Georgomanolis Athanasia Mizi Argyris Papantonis 《Molecular systems biology》2021,17(6)