Search results for "Vivo"
showing 10 items of 1905 documents
Surface Modification of Porous Polyethylene Implants with an Albumin-Based Nanocarrier-Release System
2021
Background: Porous polyethylene (PPE) implants are used for the reconstruction of tissue defects but have a risk of rejection in case of insufficient ingrowth into the host tissue. Various growth factors can promote implant ingrowth, yet a long-term gradient is a prerequisite for the mediation of these effects. As modification of the implant surface with nanocarriers may facilitate a long-term gradient by sustained factor release, implants modified with crosslinked albumin nanocarriers were evaluated in vivo. Methods: Nanocarriers from murine serum albumin (MSA) were prepared by an inverse miniemulsion technique encapsulating either a low- or high-molar mass fluorescent cargo. PPE implants …
Hypoxia-Induced Extracellular Acidosis Increases p-Glycoprotein Activity and Chemoresistance in Tumors in Vivo via p38 Signaling Pathway
2011
Due to inadequate perfusion, tumors develop hypoxia and extracellular acidosis. In vitro, this acidic environment (pH=6.6) has a strong impact on the acitvity of the p-glycoprotein (pGP) drug transporter responsible for multidrug resistance. This effect is most probably mediated via p38 and/or ERK1/2 signalling pathways. The aimof the studywas to analyzewhether these findings also play a role for chemosensitivity in solid growing tumors in vivo. Therefore, experimental R3327-AT1 tumors of the rat were exposed to an acidifying treatment leading to forced glycolysis. The intratumoral pO21 was determined polarographically and the extracellular pH was measured with needle electrodes. In additio…
Efficient gene therapy based targeting system for the treatment of inoperable tumors
2012
Background A considerable percentage of tumors are not amenable to surgery. We have designed a simple and powerful targeting system that offers an alternative option for the multi-component pre-targeting strategies used clinically. This targeting system can be used for any type of solid tumors independent of the tumor type, thereby omitting the need to engineer unique antibodies for each specific application or tumour type. In the present study, we show the expression of a chimeric fusion protein, which contains the low-density lipoprotein receptor transmembrane domains and avidin, after local gene transfer and its ability to bind biotinylated compounds in vivo. Methods Semliki Forest virus…
In vivo Electrochemical Monitoring of Signaling Transduction of Plant Defense Against Stress in Leaves of Aloe vera L.
2020
In vivo ANALYSIS OF SLOW CHLOROPHYLL FLUORESCENCE INDUCTION KINETICS IN ALGAE: PROGRESS, PROBLEMS AND PERSPECTIVES
1993
Overcoming of P-glycoprotein-mediated multidrug resistance of tumors in vivo by drug combinations
2014
Summary Inhibition of P-glycoprotein represents an attractive possibility to modulate resistance of cancer cells to anticancer drugs. One major strategy to overcome P-glycoprotein-mediated multidrug resistance (MDR) of tumors is to increase intracellular concentrations of anticancer drugs. This can be achieved by blocking of P-glycoprotein-mediated drug efflux using synthetic or natural small molecules or monoclonal antibodies, which bind to various parts of the efflux channel. Another possibility to increase intracellular drug concentrations can be reached by nanoparticles. A further major strategy to overcome MDR involves the downregulation of P-glycoprotein expression either by therapeut…
Release of Inflammatory Mediators (PGE2, IL-6) by Fenofibric Acid-Photosensitized Human Keratinocytes and Fibroblasts
1998
Ultraviolet-A radiation has weak effects on the release of inflammatory mediators by skin cells due to the poor overlap between UVA wavelengths and the absorption spectra of the relevant chromophores of key biomole-cules. However, this situation could be very different in the presence of a photosensitizing drug. To investigate this issue, we have irradiated human skin cells (keratinocytes and fibroblasts) in the presence of fenofibric acid (the active phototoxic metabolite of fenofibrate). The results of this research show a dual effect on the production/release of inflammatory mediators: the synthesis of the proinflammatory cytokine interleukin-6 becomes strongly inhibited at photosensitiz…
Intertissue Flow of Glutathione (GSH) as a Tumor Growth-promoting Mechanism
2011
B16 melanoma F10 (B16-F10) cells with high glutathione (GSH) content show high metastatic activity in vivo. An intertissue flow of GSH, where the liver is the main reservoir, can increase GSH content in metastatic cells and promote their growth. We have studied here possible tumor-derived molecular signals that could activate GSH release from hepatocytes. GSH efflux increases in hepatocytes isolated from mice bearing liver or lung metastases, thus suggesting a systemic mechanism. Fractionation of serum-free conditioned medium from cultured B16-F10 cells and monoclonal antibody-induced neutralization techniques facilitated identification of interleukin (IL)-6 as a tumor-derived molecule prom…
Organometallic complexes with biological molecues, part 3.in vivo cytotoxicity of diorganotin (IV) chloro and triorganotin (IV) chloro derivatives of…
1994
In order to obtain a continuous source of mitotic metaphases, gill tissue of Aphaius fasciatus (Pisces, Cyprinodontiformes) has been successfully employed. Results gathered after exposure of fish to R2SnClpenG, R3SnClpenGNa, to the parents R2SnCl2, R3SnCl and to penGNa (penGNa = penicillinGNa; R = methyl, butyl and phenyl) suggest that both the parent organotin (IV) chloride and organotin (IV) chloropenG derivatives are toxic while penGNa exerts no significant toxic activity. Essentially, all of the chromosome abnormalities are classifiable as irregularly staining of chromosomes, breakages, side-arm bridges or pseudochiasmata.