排序方式: 共有276条查询结果,搜索用时 31 毫秒
71.
Abouzar MH Poghossian A Razavi A Williams OA Bijnens N Wagner P Schöning MJ 《Biosensors & bioelectronics》2009,24(5):1298-1304
The feasibility of a capacitive field-effect EDIS (electrolyte-diamond-insulator-semiconductor) platform for multi-parameter sensing is demonstrated by realising EDIS sensors with an O-terminated nanocrystalline-diamond (NCD) film as transducer material for the detection of pH and penicillin concentration as well as for the label-free electrical monitoring of adsorption and binding of charged macromolecules, like polyelectrolytes. The NCD films were grown on p-Si-SiO(2) substrates by microwave plasma-enhanced chemical vapour deposition. To obtain O-terminated surfaces, the NCD films were treated in an oxidising medium. The NCD-based field-effect sensors have been characterised by means of constant-capacitance method. The average pH sensitivity of the O-terminated NCD film was 40 mV/pH. A low detection limit of 5 microM and a high penicillin G sensitivity of 65-70 mV/decade has been obtained for an EDIS penicillin biosensor with the adsorptively immobilised enzyme penicillinase. Alternating potential changes, having tendency to decrease with increasing the number of adsorbed polyelectrolyte layers, have been observed after the layer-by-layer deposition of polyelectrolyte multilayers, using positively charged PAH (poly (allylamine hydrochloride)) and a negatively charged PSS (poly (sodium 4-styrene sulfonate)) as a model system. The response mechanism of the developed EDIS sensors is discussed. 相似文献
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Manno CS Pierce GF Arruda VR Glader B Ragni M Rasko JJ Rasko J Ozelo MC Hoots K Blatt P Konkle B Dake M Kaye R Razavi M Zajko A Zehnder J Rustagi PK Nakai H Chew A Leonard D Wright JF Lessard RR Sommer JM Tigges M Sabatino D Luk A Jiang H Mingozzi F Couto L Ertl HC High KA Kay MA 《Nature medicine》2006,12(3):342-347
We have previously shown that a single portal vein infusion of a recombinant adeno-associated viral vector (rAAV) expressing canine Factor IX (F.IX) resulted in long-term expression of therapeutic levels of F.IX in dogs with severe hemophilia B. We carried out a phase 1/2 dose-escalation clinical study to extend this approach to humans with severe hemophilia B. rAAV-2 vector expressing human F.IX was infused through the hepatic artery into seven subjects. The data show that: (i) vector infusion at doses up to 2 x 10(12) vg/kg was not associated with acute or long-lasting toxicity; (ii) therapeutic levels of F.IX were achieved at the highest dose tested; (iii) duration of expression at therapeutic levels was limited to a period of approximately 8 weeks; (iv) a gradual decline in F.IX was accompanied by a transient asymptomatic elevation of liver transaminases that resolved without treatment. Further studies suggested that destruction of transduced hepatocytes by cell-mediated immunity targeting antigens of the AAV capsid caused both the decline in F.IX and the transient transaminitis. We conclude that rAAV-2 vectors can transduce human hepatocytes in vivo to result in therapeutically relevant levels of F.IX, but that future studies in humans may require immunomodulation to achieve long-term expression. 相似文献
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Polycyclic aromatic hydrocarbons have been shown to cause oxidative stress in vitro and in vivo in various animal models but the mechanisms by which these compounds produce oxidative stress are unknown. In the current study we have investigated the role of the aryl hydrocarbon receptor (AHR) in the production of reactive oxygen species (ROS) by its cognate ligands and the consequent effect on cyp1a1 activity, mRNA and protein expressions. For this purpose, Hepa 1c1c7 cells wild-type (WT) and C12 mutant cells, which are AHR-deficient, were incubated with increasing concentrations of the AHR-ligands, benzo[a]pyrene (B[a]P, 0.25-25 μM), 3-methylcholanthrene (3MC, 0.1-10 μM) and β-naphthoflavone (βNF, 1-50 μM). The studied AHR-ligands dose-dependently increased lipid peroxidation in WT but not in C12 cells. However, only B[a]P and βNF, at the highest concentrations tested, significantly increased H2O2 production in WT but not C12 cells. The increase in lipid peroxidation and H2O2 production by AHR-ligands were accompanied by a decrease in the cyp1a1 catalytic activity but not mRNA or protein expressions, which were significantly induced in a dose-dependent manner by all AHR-ligands, suggesting a post-translational mechanism is involved in the decrease of cyp1a1 activity. The AHR-ligand-mediated decrease in cyp1a1 activity was reversed by the antioxidant N-acetylcysteine. Our results show that the AHR-ligands induce oxidative stress by an AHR-dependent pathway. 相似文献
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Cheraghi Hossein Zendehdel Morteza GhiasiGhalehkandi Jamshid Tajik Parviz Panahi Negar 《International journal of peptide research and therapeutics》2019,25(3):1105-1111
International Journal of Peptide Research and Therapeutics - The correlation between leptin, nutritional status and reproductive performance is known but its effect on male obese is not fully... 相似文献
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Shahnaz Razavi Mohammad Mardani Mohammad Kazemi Ebrahim Esfandiari Manizheh Narimani Abolghasem Esmaeili Nafiseh Ahmadi 《Cellular and molecular neurobiology》2013,33(2):283-289
The Schwann cells (SCs) may be obtain from nerve biopsies for autologous transplantation. However, it is difficult to obtain sufficient amount of SCs for clinical applications. Human adipose-derived stem cells (ADSCs) can be induced to differentiate into Schwann-like cells (S-like cells) and used for autologous transplantation. However, effect of leukemia inhibitory factor (LIF) on the myelinogenic ability of SC-like cells induced from human ADSC is not investigated yet. The aim of this study was to evaluate of the effect of exogenous LIF on myelinogenic potential of differentiated cells in vitro. ADSCs were harvested from human fat tissue and characterized using flow cytometry. Human ADSCs were treated for sphere formation and LIF was added to terminal differentiation medium. GFAP/S100β and MBP markers were used to confirm differentiation of human ADSCs, and myelinogenic ability of SC-like cells, respectively, using both immunostaining and real-time RT-PCR analysis. The analysis for GFAP+/S100β+ revealed that LIF can increase both differentiated cells rates and the percentage of myelinating SC-like cells (p < 0.05). Our data showed that SC-like cells induced from human ADSCs were able to generate myelin when exposed to LIF and these cells could be a potential source for the treatment of peripheral and central axonal injuries. 相似文献
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Internal ribosome entry site (IRES)-mediated translation is an essential replication step for certain viruses. As IRES-mediated translation is regulated differently from cap-dependent translation under various cellular conditions, we sought to investigate whether temperature influences efficiency of viral IRES-mediated translation initiation by using bicistronic reporter constructs containing an IRES element of encephalomyocarditis virus (EMCV), foot-and-mouth disease virus (FMDV), hepatitis C virus (HCV), human rhinovirus (HRV) or poliovirus (PV). Under mild hypothermic conditions (30 and 35°C), we observed increases in the efficiency of translation initiation by HCV and HRV IRES elements compared to translation initiation at 37°C. The promotion of HRV IRES activity was observed as early as 2 hours after exposure to mild hypothermia. We also confirmed the promotion of translation initiation by HRV IRES under mild hypothermia in multiple cell lines. The expression levels and locations of polypyrimidine tract-binding protein (PTB) and upstream of N-Ras (unr), the IRES trans-acting factors (ITAFs) of HCV and HRV IRES elements, were not modulated by the temperature shift from 37°C to 30°C. Taken together, this study demonstrates that efficiency of translation initiation by some viral IRES elements is temperature dependent. 相似文献