MTT Method (mtt + method)

Distribution by Scientific Domains

Selected Abstracts

Cytotoxicity of doxorubicin-loaded Con A-liposomes

Hercília Maria Lins Rolim Santos
Abstract The present study investigated the potential of Concanavalin A lectin (Con A) conjugated to liposomes (Con A-liposomes) for targeting doxorubicin (DOX) to cells. The physicochemical properties and the cytotoxicity of DOX-loaded Con A-liposomes were evaluated. DOX-loaded Con A-liposomes were prepared by incubation of DOX-loaded liposomes with a Con A-SATA derivative. Lectin biological activity was monitored before and after conjugation by a hemagglutinating assay. The cytotoxicity of DOX-loaded Con A-liposomes was evaluated in terms of the inhibition of NCI-H299 and HEp-2 cell proliferation using the MTT method. The affinity of lectinized liposomes with these cells was thus assessed by evaluating the cytotoxic effect of the DOX released into cells. Stable DOX-loaded Con A-liposomes were obtained and their high affinity for cells was corroborated. The encapsulation of DOX into Con A-liposomes produced an inhibition of roughly 70% of Hep-2 cell proliferation and 50% of cell inhibition was verified on HCI-H292. DOX in solution was able to inhibit only 20% of cell proliferation for both cell lines. Unloaded Con A-liposomes were not cytotoxic. The encapsulation of DOX into Con A-liposomes improves drug penetration into cells, thereby enhancing its cytotoxicity, especially in Hep-2 cells. Drug Dev. Res. 67:430,437, 2006. © 2006 Wiley-Liss, Inc. [source]

Cytotoxicity and sealing properties of four classes of endodontic sealers evaluated by succinic dehydrogenase activity and confocal laser scanning microscopy

Serge Bouillaguet
The objectives of this study were to evaluate the cytotoxicity and sealing properties of four classes of endodontic sealers (PCS/Kerr, RoekoSeal/Roeko, TopSeal/Dentsply, and EndoREZ/Ultradent). For cytotoxicity testing (MTT method), the materials were either placed immediately in contact with cultured cells or 24 h after setting, then evaluated at three subsequent time points (24 h, 48 h, or 1 wk). For the leakage study, extracted human roots were obturated with acrylic cones and sealers and immersed for 48 h into rhodamine-labeled lipopolysaccharide. The roots were then observed under a confocal laser scanning microscope to estimate (semiquantitatively) the presence of the rhodamine-lipopolysaccharide (LPS) inside the canal. The results showed that cytotoxicity generally increased with time, and that most materials pose significant cytotoxic risks, particularly in the freshly mixed condition. Further, all materials showed significant leakage although there was large variation among teeth. Overall, the silicon-based material (Roeko Seal) was less cytotoxic and more effective in sealing root canals against LPS leakage than other materials. [source]

Effects of prolactin on intracellular calcium concentration and cell proliferation in human glioma cells

GLIA, Issue 3 2002
Thomas Ducret
Abstract Prolactin (PRL) has several physiological effects on peripheral tissues and the brain. This hormone acts via its membrane receptor (PRL-R) to induce cell differentiation or proliferation. Using reverse transcription,polymerase chain reaction (RT-PCR) combined with Southern blot analysis, we detected PRL-R transcripts in a human glioma cell line (U87-MG) and in primary cultured human glioblastoma cells. These transcripts were deleted or not in their extracellular domains. We examined the effects of PRL on intracellular free Ca2+ concentration ([Ca2+]i) in these cells in order to improve our understanding of the PRL transduction mechanism, which is still poorly documented. [Ca2+]i was measured by microspectrofluorimetry using indo-1 as the Ca2+ fluorescent probe. Spatiotemporal aspects of PRL-induced Ca2+ signals were investigated using high-speed fluo-3 confocal imaging. We found that physiological concentrations (0.4,4 nM) of PRL-stimulated Ca2+ entry and intracellular Ca2+ mobilization via a tyrosine kinase,dependent mechanism. The two types of Ca2+ responses observed were distinguishable by their kinetics: one showing a slow (type I) and the other a fast (type II) increase in [Ca2+]i. The amplitude of PRL-induced Ca2+ increases may be sufficient to provoke several physiological responses, such as stimulating proliferation. Furthermore, PRL induced a dose-dependent increase in [3H]thymidine incorporation levels and in cellular growth and survival, detected by the MTT method. These data indicate that PRL induced mitogenesis of human glioma cells. GLIA 38:200,214, 2002. © 2002 Wiley-Liss, Inc. [source]

Two New Eremophilane-Type Sesquiterpenoids from the Rhizomes of Ligularia veitchiana (Hemsl.) Greenm

Cai-Fang Wang
Abstract Two new eremophilane-type sesquiterpenoids eremophil-6-en-11-ol (1) and (7,,9,,10,)-9,10-epoxy-eremophilan-11-ol (2), together with a known eremophilane-type (6,,8,)-6,8-dihydroxyeremophil-7(11)-en-12-oic acid 12,8-lactone (3) were isolated from the rhizomes of Ligularia veitchiana. The structures of 1 and 2 were established by spectral analysis including 1H- and 13C-NMR, HSQC, HMBC, and HR-ESI-MS data. The compounds 1 and 3 were assessed against lung-cancer (A549) and stomach-cancer (BCG823) cell lines by the MTT method. The results showed that 1 exhibited significant inhibiting activities on the growth of these cancer cells with IC50 values between 1,100,,g/ml, whereas compound 3 had no effect on the same cell lines. [source]

Synthesis and antitumor activities of 2-(substituted)phenyl-1,2,4-triazolo[1,5- a]pyridines

Guolin Zhang
Twenty-three 2-(substituted)phenyl-1,2,4-triazolo[1,5- a]pyridines have been synthesized by cycloadditison reaction between N -amino methylpyridinium mesitylenesulfonates and substituted benzonitriles under the presence of potassium hydroxide at room temperature. The structures of all products were confirmed by 1H NMR, MS and elemental analyses. The antitumor activities of these compounds were evaluated against human ovary cancer cell line (HO-8910) in vitro by MTT method. The preliminary results showed that compound 1e (IC50 28,M) and compound 1w (IC50 31,M) exhibited stronger antitumor activities than cisplatin (IC50 35,M) in vitro. Hence, 1e and 1w have potential antitumor activities and are worth further investigation. [source]

Design, Synthesis, and Pharmacological Investigation of Iodined Salicylimines, New Prototypes of Antimicrobial Drug Candidates

Suo-Ping Xu
Abstract A series of 3,5-diiodo-salicylalidene Schiff bases (compounds 1,35) has been synthesized and tested for antimicrobial activity. The compounds were assayed for antibacterial activities by the MTT method. Some of the compounds inhibit the growth of a broad range of bacteria including the species of Bacillus subtilis, Staphylococcus aureus, Streptococcus faecalis, Pseudomonas aeruginosa, Escherichia coli, and Enterobacter cloacae. Among them, compounds 2-[(4-chloro-phenylimino)methyl]-4,6-diiodo-phenol 11 and 2,4-diiodo-6-[(2-morpholin-4-yl-ethylimino)methyl]phenol 19 showed the most potent antibacterial activity with MIC of 3.1, 12.9, 3.3, 6.5, 12.9, 3.3 and 3.2, 12.8, 3.2, 12.8, 12.8, 3.2 ,M against B. subtilis, S. aureus, S. faecalis, P. aeruginosa, E. Coli, and E. cloacae, respectively. [source]

Is neuroglobin (Ngb) a perspective for glaucoma?

Purpose To further explore the mechanisms of Ngb function in the retina, and investigate the possible neuroprotective potency of this O2-binding protein in glaucoma. Our project will potentially open exciting perspectives for the treatment and prognosis of the blinding condition of glaucoma. Methods 1) In vitro: We will set up cultures for primary RGCs. The cultured RGCs will be subjected to hypoxia by incubation in a controlled-atmosphere incubator. Cell survival and apoptosis will be assessed using MTT method and TUNEL staining. Ngb expression in normoxic and hypoxic cells will be compared. Additionally, the RGCs will be transfected with plasmids expressing Ngb mRNA to evaluate the neuroprotective effect of Ngb. 2) In vivo: The ischemia/reperfusion model and the staurosporine intravitreal injection model cause acute RGC loss. We will also use a laser model to induce chronic elevated IOP by obstructing the aqueous outflow pathway. We will first analyze upregulated Ngb expression in these models. The localization of both Ngb mRNA and protein will be assessed. Ngb-Tg mice will be subjected to the glaucoma models. We will measure cell density or retinal thickness and perform electroretinography to evaluate the physiological function of retina. We will also analyse the possible contribution of oxidative stress via immunostainings for ROS and determine possible effects on NO scavenging by evaluating the expression of NOS. Furthermore, we will transfect RGCs in vivo using intravitreal injections of a Ngb expressing adeno-associated virus (AAV) to test the therapeutic potential of Ngb. Conclusion Our project will not only provide us with an improved understanding of neuroglobin, but also open a new perspective for the treatment of retinal ganglion cell apoptosis and glaucomatous neuropathy. [source]