PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “TETRAZOLIUM COMPOUNDS”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 883 records · Page 49Linked to original sources
PubMed1995

A colorimetric LDH assay for the titration of infectivity and the evaluation of anti-viral activity against ortho- and paramyxoviruses.

A rapid and precise screening assay was developed for in vitro evaluation of anti-orthomyxo- and anti-paramyxovirus agents. The procedure is spectrophotometrical assessment for viability of cells via extracellular leakage of lactic dehydrogenase (LDH). HMV-II cells, a human melanoma cell line was found to be suitable for the titration of virus infectivity and screening of anti-viral agents for orthomyxo- and paramyxoviruses. Comparative titration of infectivity of stock viruses by the LDH and the MTT in site reduction of 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) methods with HMV-II cells as well as plaque titration with MDCK, Vero and HeLa cells was carried out. The LDH method was comparable or more sensitive for influenza viruses (FLUV)-A, B, C, parainfluenza viruses (PFLUV)-1, 2 and less sensitive for PFLUV-3, mumps virus (MPSV), measles viruses (MLSV) and respiratory syncytial virus (RSV) than the plaque titration. The 50% effective concentration (EC50) of 1-beta-D-ribofuranosyl-1, 2, 4-triazol-3-carboxamide (ribavirin) and 5-ethynyl-1-beta-D-ribofuranosyl-imidazole-4-carboxamide (EICAR) against orthomyxo- and paramyxoviruses were examined comparatively by the LDH, MTT and plaque reduction (PR) methods. The EC50 values of FLUV-C and PFLUV-1 were able to be evaluated only by the LDH but not by the MTT and PR methods. The LDH method with HMV-II cells simplifies the assay procedure and permits the evaluation of a large number of compounds for anti-orthomyxo- and anti-paramyxoviruses activity in vitro.

Antiviral Agents↗
PubMed1999

Superoxide anion scavenging properties of fluvastatin and its metabolites.

We investigated the in vitro superoxide anion scavenging activities of fluvastatin and its metabolites. Fluvastatin showed dose-dependent superoxide anion scavenging activity in the NADH/phenazine methosulphate (PMS)/nitroblue tetrazolium (NBT) system, and the effect was as potent as the reference antioxidant, trolox, which is a water-soluble alpha-tocopherol derivative. The superoxide anion scavenging activities of the major metabolites of fluvastatin (M2, M3, M4, M7) were also determined in this system. All of these metabolites showed the activity. In particular, M2 and M3, which possess a phenolic hydroxyl group at the 5 or 6-position of the indole moiety, respectively, showed 3 times stronger activities than that of fluvastatin. Further, we also determined the effects of fluvastatin, M2 and M3 on phorbol myristate acetate (PMA)-induced superoxide anion generation in human peripheral blood polymorphonuclear leukocytes (PMN). The compounds tested also showed a depressing effect on the amount of superoxide anion in this system. We suggest that fluvastatin and its metabolites have the potential to protect cells or lipids from oxidative modification mediated by superoxide anion.

Cells, Cultured↗
PubMed2004

Comparison of alamar blue and MTT assays for high through-put screening.

The performance of alamar blue and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) cell viability assays in a high through-put format were compared. A total of 117 drugs chosen for their wide range of therapeutic areas were screened at 10 microM using both assays in human hepatoma cell line HepG2. Except for terfenadine and astemizole, which performed consistently in both assays, the alamar blue assay was slightly more sensitive than the MTT assay for most compounds. The MTT assay was less sensitive detecting an effect for daunorubicin and trifluoperazine. Seven drugs, astemizole, daunorubicin, ellipticine, fluphenazine, terfenadine, thioridazine and trifluoperazine, had percent viability results of 55% or less in the alamar blue assay at the single point screen. These were re-tested in both assays for reconfirmation of cytotoxicity and determination of the EC50 values. Except for daunorubicin, the EC50 values were comparable in both assays. Based on these results and the Z'-factor assessment of assay quality, both assays provided useful information to identify in vitro cytotoxic drugs at early stages of drug candidate selection. However, careful interpretation of data is warranted due to the possibility of false positive or negative results caused by inducers and/or inhibitors of metabolic enzymes that are responsible for transformation of cell toxicity end points, as we demonstrated using dicumarol.

Carcinoma, Hepatocellular↗
PubMed2006

Investigation of the hepatotoxicity profile of chemical entities using Liverbeads and WIF-B9 in vitro models.

The cytotoxicity profile of various chemical entities was evaluated using two in vitro hepatocyte models. Liverbeads is a cryopreserved model consisting of primary hepatocytes entrapped in alginate beads. WIF-B9 is a hybrid cell line obtained by fusion of rat hepatoma (Fao) and human fibroblasts (WI38). Various reference hepatotoxicants were tested and ranked according to their equivalent concentration 50 (EC50) for various biochemical endpoints (lactate dehydrogenase (LDH) release, 3-(4,5 dimethylthiazol 2yl)-2,5-diphenyl-2H tetrazolium bromure (MTT) activity, adenosine triphosphate (ATP) and glutathione (GSH) levels). The ranking obtained was comparable in both models and consistent with previously published results on hepatocyte monolayers. Ketoconazole, erythromycin estolate, retinoic acid, telithromycin and alpha-naphthyl-isothiocyanate were among the most toxic chemicals in both models, with an EC50 < 200 microM. Troleandomycin, spiramycin, erythromycin, diclofenac, taurodeoxycholate, warfarin, galactosamine, valproic acid and isoniazid were found to be less toxic. Few marked differences, potentially linked to metabolism pathways, were observed between EC50s in the two models for compounds such as cyclosporine A (10 and > 831 microM) and warfarin (5904 and 1489 microM) in WIF-B9 and Liverbeads, respectively. The results obtained indicate that Liverbeads and WIF-B9 cells are reliable in vitro models to evaluate the hepatotoxic potential of a wide range of chemicals, irrespective of structure and pharmaceutical class.

Adenosine Triphosphate↗
PubMed1996

Assessment of a cytoprotection assay for the discovery and evaluation of anti-human immunodeficiency virus compounds utilizing a genetically-impaired virus.

A biologically contained cytoprotection assay was developed to screen inhibitors of the human immunodeficiency virus without the need for high level containment or practices. The virus used has multiple point mutations that have destroyed its ability to produce both Rev and Tat, proteins essential for virus replication in vitro. The original cell line employed (CEM-SSTART) contains a genetic construct that allows for the continuous expression of both Rev and Tat, and a subclone (1A2) was developed that provides for maximum acute cytopathic effect. The National Cancer Institute's AIDS drug screening assay was used to test known drugs with both HIVIIIB virus in the T4 lymphocytic cell line CEM-SS and mutant virus in the 1A2 subclone. This cell-based assay uses the tetrazolium salt, XTT, as an indicator of cellular metabolism after the cells have been infected with virus. The results of extensive testing have shown that the assay using mutant virus is comparable to the current NCI AIDS drug screen. After 42 days in 1A2 or CEM-SS cell culture, the virus or the integrated genome did not revert to wild-type, and the virus produced in 1A2 cells was unable to replicate in PBMCs. Mutant viral stocks were devoid of wild-type virus as determined by a PCR assay that would have found 60-600 copies of mutant RNA. These materials, which are now available to the scientific community (NIH AIDS Research and Reference Reagent Program), should be useful tools to screen and test compounds for potential inhibition of HIV in laboratories not equipped to maintain and use wild-type infectious virus.

Antiviral Agents↗
PubMed1995

1,25-Dihydroxyvitamin D3 promotes prostaglandin E1-induced differentiation of HL-60 cells.

Human promyelocytic HL-60 cells can be induced by biochemical agents to differentiate in vitro towards divergent types of myelomonocytic cells. It has been reported that prostaglandin E1 (PGE1) can induce granulocytic differentiation and that 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) can induce monocytic differentiation. We have now examined the effects of these compounds, both alone and in combination, on HL-60 cell differentiation. PGE1 (1 microgram/ml) or 1,25(OH)2D3 (10 nM) each inhibited cell proliferation over 48-96 hours of treatment, but combined treatment with both agents was necessary to produce a strong inhibition. The percentage of HL-60 cells that can reduce nitroblue tetrazolium (NBT) (a characteristic index of early monocytic or granulocytic differentiation) increased 13-fold within 72 hours of PGE1 treatment, and 1,25(OH)2D3 produced a five-fold stimulation. However, combined treatment (PGE1 plus 1,25(OH)2D3) produced a dramatic 35-fold increase. HL-60 cells did not produce significant levels of nitric oxide (NO) before 48 hours in culture, and treatment with PGE1 or 1,25(OH)2D3 did not significantly increase cellular NO elaboration over control levels. However, combined treatment produced a striking 12-fold increase over control levels. Similarly, combined treatment was necessary to obtain the maximal time-dependent stimulation of cellular lactate dehydrogenase (LDH) activity (a marker of granulocytic differentiation) as well as acid phosphatase (ACP) activity. During this same period of time, PGE1, but not 1,25(OH)2D3, markedly stimulated cellular elaboration of interleukin (IL)-1 alpha, IL-6, and tumor necrosis factor (TNF)-alpha, and 1,25(OH)2D3 cotreatment strongly augmented these effects. Thus, combined treatment with 1,25(OH)2D3 plus PGE1 generally augmented the apparent conversion of these cells, producing synergistic (multiplicative) or additive effects. Furthermore, PGE1 induced within 48 hours the more general phenotypic changes classically associated with the differentiation of these cells: increased expression of chloroacetate esterase (ChAE) (a granulocytic marker), decreases in the nuclear/cytoplasmic ratio (characteristic of development beyond the promyelocyte/myelocyte stage), and major alterations in morphology from floating spherical cells to loosely adherent, elliptical polygons. 1,25(OH)2D3 had little effect itself on most of these parameters, but augmented the morphological changes induced by PGE1 treatment. Within 48 hours, the ability of these cells to reduce the tetrazolium salt WST-1, a general measure of cellular metabolic activity, was increased by PGE1, but not by 1,25(OH)2D3; however, the combination of 1,25(OH)2D3 and PGE1 again produced the strongest stimulation. Similarly, only PGE1 significantly reduced intracellular ATP levels, but combined treatments produced a more pronounced decrease. In summary, our findings suggest that PGE1, not 1,25(OH)2D3, is sufficient to promote rapid in vitro differentiation of HL-60 cells along the granulocyte pathway; however, the PGE1-induced conversion of these cells is markedly augmented by cotreatment with 1,25(OH)2D3. In addition, these converted HL-60 cells preferentially utilize the glycolytic pathway, rather than the citric acid cycle, for production of ATP, a metabolic characteristic that resembles that described for mature granulocytes.

Acid Phosphatase↗
PubMed1989

Protection of crystal-induced polymorphonuclear leukocyte membranolysis by phosphocitrate.

The protection afforded by phosphocitrate, a phosphorylated polycarboxylic acid, against crystal-induced membrane damage to polymorphonuclear leukocytes was studied in vitro. Membranolysis was assessed by nitro blue tetrazolium salt reduction, lactate dehydrogenase release, and scanning electron microscopy. Phosphocitrate protected strongly against hydroxyapatite crystal-induced damage, an action attributable to crystal surface binding of phosphocitrate rather than to the membrane. The ability of phosphocitrate to prevent hydroxyapatite crystallization, together with its membrane protective effect against preformed crystals, would suggest that the compound might have a useful future role against crystal-induced arthropathies.

Apatites↗
PubMed2000

Cyclopentene dialdehydes from Tabebuia impetiginosa.

The isolation of two cyclopentene dialdehydes, 2-formyl-5-(4'-methoxybenzoyloxy)-3-methyl-2-cyclopentene-1-acetal dehyde, and 2-formyl-5-(3', 4'-dimethoxybenzoyloxy)-3-methyl-2-cyclopentene-1-acetaldehyde, from the bark of Tabebuia impetiginosa is reported. The structures were established by analysis of spectroscopic data. These compounds showed anti-inflammatory activity.

Aldehydes↗
PubMed2002

Comparison of idarubicin and daunorubicin regarding intracellular uptake, induction of apoptosis, and resistance.

Anthracycline antibiotics are widely used as anticancer agents. Idarubicin (4-demethoxydaunorubicin; Ida), a semisynthetic derivative of daunorubicin (Dnr) is more potent than the parent compound in vitro and in vivo. The equitoxic dose of Ida in patients is about one-fourth of that of Dnr. We compared these drugs regarding cytotoxicity, apoptosis induction, and resistance mechanisms in human leukaemic cell lines. Cytotoxicity was studied by means of the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide assay and drug-induced apoptosis by means of the Annexin V-fluorescein isothiocyanate method at similar intracellular concentrations (extracellular concentrations of 0.35 microM for Ida and 1 microM for Dnr). Ida was at least twice as potent as Dnr in MOLT-4, HL60, CEM, and K562 cell lines. It took 8 h for Ida to induce approximately 20% apoptosis, but at least 22 h for Dnr to reach 20% apoptosis at identical intracellular concentration. Ida induces a faster and higher apoptosis rate compared with Dnr. The human chronic myelogenous leukaemia cell line (K562) was selected for resistance to Dnr and Ida with and without verapamil (Ver). Continuous incubation with Dnr, but not with Ida, led to an increased mdr1 gene expression as assessed by real-time PCR. The development of mdr1 gene expression in Dnr-resistant cells could be reversed by the presence of Ver. Ver also reversed the cytotoxicity to Dnr, but not to Ida, in K562/Dnr cells. The results show that Ida is more effective than Dnr in inducing apoptosis and that there are differences in resistance mechanisms between the drugs.

Antibiotics, Antineoplastic↗
PubMed1999

Recombinant human erythropoietin stimulates production of interleukin 2 by whole blood cell cultures of hemodialysis patients.

The impairment of function of human T lymphocytes, leading to an inappropriate cytokine production, is partially responsible for defective immunological response in hemodialysis patients (HD). Recent data suggest that recombinant human erythropoietin (rhEPO) may exert immunological effects. The aim of this study was to find out whether rhEPO treatment of the HD patients may have an effect on the interleukin 2 (IL-2) production by their whole blood cell cultures. The study was carried out in 10 HD patients receiving rhEPO for 6 months. Compared with the levels seen before the treatment, the concentration of IL-2 increased in the phytohemagglutinin-stimulated whole blood cell cultures of 7 of 10 patients under study. Addition of rhEPO in vitro to the whole blood cell cultures of the HD patients before implementation of erythropoietin confirmed that rhEPO is able to directly stimulate IL-2 production. Our studies show that the therapy with rhEPO affects IL-2 secretion.

Adjuvants, Immunologic↗
PubMed2005

A novel celecoxib derivative potently induces apoptosis of human synovial fibroblasts.

We have already demonstrated that celecoxib, a selective cyclooxygenase (COX)-2 inhibitor, has a proapoptotic effect on synovial fibroblasts obtained from patients with rheumatoid arthritis (RA). Here we report on the development of two novel derivatives of celecoxib, N-(2-aminoethyl)-4-[5-(4-tolyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamide (TT101) and 4-[5-(4-aminophenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamide (TT201), including whether these compounds have a proapoptotic effect on synovial fibroblasts. Synovial fibroblasts were harvested from the synovial tissues of patients with RA or osteoarthritis (OA). Cell proliferation and cell viability were assessed by the incorporation of 5-bromo-2'-deoxyuridine and by the 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium monosodium salt assay, respectively. Apoptosis was detected by the identification of DNA fragmentation, and activation of caspase-3 was detected by the addition of a caspase-3 substrate to cell lysates. Production of prostaglandin E(2) by RA synovial fibroblasts was analyzed by enzyme-linked immunosorbent assay. TT101 inhibited the proliferation of RA and OA synovial fibroblasts in a concentration-dependent manner. It caused a marked decrease of cell viability and induced DNA fragmentation more potently than either celecoxib or SC-236 (4-[5-(4-chlorophenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamide). TT101 also increased caspase-3 activity. The order of potency of the COX-2 inhibitory activity of these drugs in RA synovial fibroblasts was celecoxib = SC-236 > rofecoxib > TT201 > TT101. In conclusion, we developed TT101 with about a 5- to 10-fold stronger proapoptotic effect on RA and OA synovial fibroblasts compared with that of celecoxib. Although the mechanism of action of TT101 remains unclear, it may have potential as a novel antirheumatic agent.

Apoptosis↗
PubMed2002

Cytotoxic effects of diazenes on tumor cells in vitro.

BACKGROUND: We have shown previously that diazenecarboxamides (diazenes) were cytotoxic for several tumor cell lines. Their target seems to be the intracellular glutathione (GSH). To improve the solubility and biological activity of these drugs, new compounds have been synthesized. In the present study we examined the cytotoxic effect of six new diazenes: BR-25, UP-39, UP-11, JK-1024, RL-514 and RL-625. METHODS: The cytotoxicity of diazenes was tested on nine human tumor cell lines: laryngeal carcinoma HEp2 cells, cervical carcinoma HeLa cells, mammary carcinoma MCF-7 cells, breast adenocarcinoma SK-BR-3 cells, and glioblastoma A1235 cells and their four drug-resistant cell lines. Cytotoxicity was determined using the colorimetric MTT assay. The intracellular GSH content (following the treatment with diazenes) was examined spectrophotometrically in human cervical carcinoma cells by the procedure developed by Tietze. RESULTS: Results show that diazene UP-39 was mostly efficient, significantly reducing the cell survival of all nine cell lines examined, including four drug-resistant cell lines. Diazenes UP-11, RL-514 and BR-25 given in the highest concentrations decreased the survival of some examined cell lines, but to less than 50%. Diazenes RL-625 and JK-1024 had no influence on the cell survival. None of the examined diazenes significantly influenced the intracellular level of GSH. CONCLUSION: Our results suggest that diazene UP-39 may be a promising new drug for the treatment of tumors and encourage further research on this compound.

Antineoplastic Agents↗
PubMed1984

Induction of neutrophilic differentiation of human promyelocytic leukemic cells by branched-chain carboxylic acid anticonvulsant drugs.

The anticonvulsant drug 1-methyl-1-cyclohexanecarboxylic acid ( MCCA ) has been shown to cause maturation of murine neuroblastoma cells in vitro at concentrations that are pharmacologically achievable. HL-60 human promyelocytic leukemia cells cultured with this drug underwent a dose-dependent decrease in growth. Similarly, neutrophilic differentiation, based on morphologic criteria and the acquisition of the ability to reduce nitroblue tetrazolium and phagocytose yeast, was observed. Valproic acid, a clinically available anticonvulsant that is chemically related to MCCA , likewise inhibited growth and promoted maturation of HL-60 cells, although only at concentrations above the recommended therapeutic blood levels. MCCA was additive in its ability to induce differentiation of HL-60 with retinoic acid, another compound that induces differentiation at pharmacologic concentrations. MCCA , or similar branched-chain fatty acids, may be useful in the treatment of human leukemia, particularly in combination with other differentiation-inducing drugs.

Anticonvulsants↗
PubMedDate not supplied

Growth inhibitory activity of S12363, a novel vinca alkaloid derivative on human melanoma cell lines.

The growth inhibitory activity of S12363, a new antineoplastic agent which belongs to the vinca alkaloid group incorporating an amino-phosphonate (bioester of valine), was studied on six human melanoma cell lines with different phenotypic characteristics and in vitro growth rates. S12363 was compared with vinblastine (VBL), vincristine (VCR) and vindesine (VDS) using the MTT assay. Inhibition was time- and dose-dependent. Overall, IC50 values ranged from 24-6770nM and 4.6-11.6 nM for the reference drugs and for S12363 respectively, after exposure for 1 hr. All the vinca alkaloids were more active when cells were exposed continuously for 72 hrs, inhibition by S12363 was greater than the reference drugs (p < 0.05 in 15/18 comparisons). The activities of VDS and S12363 were also compared using the clonogenic assay. IC50 values ranged from 45-500 nM and 17-75 nM respectively. On a molar basis, S12363 was significantly more active than VDS (ANOVA p < 0.0001). The shape of the cell survival curve obtained with S12363 was exponential, whereas that of VDS was of the exponential-plateau type. Furthermore, survival with higher concentrations of S12363 was inversely related to cells seeded. Cell cycle analysis showed these compounds to block cells in G2+M after exposure to their respective IC50 concentrations for 1 hr. This effect was obtained using a lower S12363 concentration. In summary, S12363 proved to be 18-83 times more active than the reference drugs in the MTT and 3-11 times more active than VDS in the clonogenic assay. Its high potency and dissimilar cell survival profile indicate that this compound possesses different biological properties, and therefore merits further in vivo evaluation.

Antineoplastic Agents, Phytogenic↗
PubMed2003

Method for measuring neurotoxicity of aggregating polypeptides with the MTT assay on differentiated neuroblastoma cells.

Reliable in vitro assays are essential for study of the effects of neurotoxic compounds such as beta-amyloid peptides (Abeta). The MTT assay has been used in cultures of different cells, e.g. SH-SY5Y neuroblastoma cells, for the quantitative measurement of Abeta toxicity. In our laboratory differentiated SH-SY5Y cells were used in the MTT assay. Cell differentiation with 10 microM all-trans-retinoic acid resulted in a constant cell number. The cells possess highly developed neurites and exhibit high sensitivity against Abeta. Owing to the constant cell number in differentiated SH-SY5Y cultures the decrease of the redox activity is directly proportional to the neurotoxicity of the substances, no correction is needed. The results of the MTT assay of Abeta peptides on differentiated SH-SY5Y cells displayed a good correlation also with the in vivo results. The present experiments reveal an effective assay for the study of potentially neurotoxic compounds.

Amyloid↗
PubMed2002

Antioxidant, free radical scavenging and anti-inflammatory effects of aloesin derivatives in Aloe vera.

Antioxidant components in Aloe vera were examined for lipid peroxidation using rat liver microsomal and mitochondrial enzymes. Among the aloesin derivatives examined, isorabaichromone showed a potent antioxidative activity. The DPPH radical and superoxide anion scavenging activities were determined. As one of the most potent components, isorabaichromone together with feruloylaloesin and p-coumaroylaloesin showed potent DPPH radical and superoxide anion scavenging activities. Electron spin resonance (ESR) using the spin trapping method suggested that the potent superoxide anion scavenging activity of isorabaichromone may have been due to its caffeoyl group. As A. vera has long been used to promote wound healing, the inhibitory effects of aloesin derivatives for cyclooxygenase (Cox)-2 and thromboxane (Tx) A 2 synthase were examined and the participation of p-coumaroyl and feruloyl ester groups in the aloesin skeleton was demonstrated. These findings may explain, at least in part, the wound healing effects of A.vera. Abbreviations. ADP:adenosine diphosphate ASA:ascorbic acid BHT:butylated hydroxytoluene BSA:bovine serum albumin DMPO:5,5-dimethyl-1-pyrroline N-oxide DPPH:1,1-diphenyl-2-picrylhydrazyl EDTA:edetic acid HEPES: N-(2-hydroxyethyl)-piperazine- N-2'-ethane-sulfonic acid NADH:reduced nicotinamide adenine dinucleotide NADPH:reduced nicotinamide adenine dinucleotide phosphate NBT:nitroblue tetrazolium Pg:prostaglandin SOD:superoxide dismutase TBA:thiobarbituric acid TCA:trichloroacetic acid XOD:xanthine oxidase

Aloe↗
PubMed1995

A screening system for antiviral compounds against herpes simplex virus type 1 using the MTT method with L929 cells.

We developed the improved MTT assay system for in vitro evaluation of anti-HSV-1 agents using L929 cells derived from mouse connective tissue. This assay system provides results in 4 days using a 96-well microplate. The EC50 values of several anti-HSV agents (ACV, BVaraU, and others) were found to be similar to those obtained by the plaque reduction method using MRC-5 cells. The present MTT assay is rapid, accurate, and may be useful as an automatic screening system for evaluation of anti-HSV-1 compounds.

Animals↗