Results 1 - 10 of 354
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[en] The published data on the synthesis, physicochemical properties, structures and reactions of 1,3-(1,3,5)- and 1,4-(1,4,5)-substituted tetrazolium salts are systematised and generalised. Their applications as starting compounds in the preparative chemistry of heterocyclic derivatives and some other branches of science and technology are reviewed. The bibliography includes 122 references.
[en] Purpose: To study potential properties of iodinated radiographic contrast media (IRCM) for intravascular use in in vitrfree radical generating reactions. Material and Methods: Superoxide (O2- ) and hydroxyl (OH) radicals were generated in xanthine oxidase and Fenton reactions. O2 - was assayed by the nitroblue tetrazolium (NBT) method, whereas OH was assayed by an aromatic hydroxylation (2-hydroxy-benzoic acid) method. Total antioxidant status (TAS) of test substances was determined by a colorimetric assay. Finally, acetyl-cholinesterase (AChE) activity was measured in the absence and presence of IRCM. Results: High concentrations (>50 mM) of IRCM inhibited O2 - production, ionic more than non-ionic IRCM. Medium concentrations (25-50 mM) of IRCM reduced OH production, and both types of IRCM were equally potent. Low concentrations (<25 mM) of non-ionic IRCM displayed higher antioxidant capacity than their ionic counterparts when tested in the TAS assay. Visipaque 320 (iodixanol) was found thave the highest TAS value, followed by Omnipaque 350 (iohexol), Hexabrix 320 (ioxaglate), and Urografin 370 (diatrizoate). Conclusion: IRCM have in vitrantioxidant properties in concentrations relevant for their clinical application. These properties may therefore be of potential importance when evaluating IRCM effects in vivo, particularly those concerning cardiovascular and renal function
[en] The preparation of [5-C14]-TTC, [5, 5'-di-C14]NT (neotetrazolium) and [5, 5'-di-C14]-BT (tetrazolium blue) starting from benzaldehyde- [1-C14] has been accomplished. The yields for both mono- and ditetrazolium salts are high, and the products can be obtained with high sp. activity. The purity of the samples was investigated by paper chromatography. In the case of ditetrazolium salts some impurities could be detected and conclusions drawn as to their structure and quantity. A method has been developed to prepare C14- labelled ditetrazolium salts of high purity. The formation of the formazan, the precursor of the tetrazolium salt, goes through an unstable intermediate of tetrazene-type structure which rearranges rapidly in basic medium, to yield the formazan. The tetrazene intermediate can be isolated under suitable conditions. By using C14-labelled benzaldehyde phenylhydrazone this rearrangement was investigated and a verification of its intramolecular character given. (author)
[fr]On a procede a la preparation de [5-C14]-TTC, de [5,5'-di-C14] NT (neotetrazolium) et de [5,5'-di-C14]-VT (bleu de tetrazolium), en partant du benzaldehyde-[1-C14]. On a pu obtenir un grand rendement, tant pour les sels de monotetrazolium que pour les sels de ditetrazolium, et des produits d'une activite specifique elevee. La purete des echantillons a ete examinee par chromatographie sur papier. Dans le cas des sels de ditetrazolium, on a pu deceler quelques impuretes et tirer des conclusions quant a leur structure et quantite. On a mis au point une methode permettant de preparer des sels de ditetrazolium marques au carbone-14 et presentant une grande purete. Dans la synthese du formazan, precurseur du sel de tetrazolium, on obtient un produit intermediaire instable d'une structure analogue a celle du tetrazene; ce produit se transforme rapidement en milieu alcalin pour donner du formazan. Le tetrazene intermediaire peut etre isole dans des conditions appropriees. On a etudie cette transformation en utilisant du benzaldehyde-phenylhydrazone marque au carbone-14, et l'on a pu verifier ainsi qu'il s'agit d'une reaction intramoleculaire. (author)
[es]Partiendo del benzaldehido-(1-14C), el autor ha sintetizado el TTC-(5-14C), el NT-(5, 5'-di-14C) (neotetrazolio) y el BT- (5, 5'-di-14C) (azul de tetrazolio). Las sales de mono- o ditetrazolio se obtienen con buen rendimiento y se logran productos de elevada actividad especifica. El autor determino la pureza de las muestras por cromatografia sobre papel. En las sales de ditetrazolio encontro algunas impurezas, que consiguio determinar cuantitativamente; asimismo establecio algunas caracteristicas de sus estructuras. Por otra parte, elaboro un metodo para obtener sales de ditetrazolio marcadas con 14C de elevada pureza. En la sintesis del formazan, el precursor de la sal de tetrazolio, se obtiene un producto intermedio inestable cuya estructura es similar a la del tetraceno. Este compuesto sufre una rapida transposicion en medio alcalino para dar lugar al formazan. Es posible aislar el producto intermedio si se trabaja en condiciones adecuadas. El autor estudia la transposicion utilizando la fenilhidrazona del benzaldehido marcado con 14C, y ha podido comprobar que se trata de una reaccion intramolecular. (author)
[ru]Iskhodya iz benzal'degida - [1-C14] udalos' izgotovit' [5-C14]-TTC, [5,5'di-C14]-NT (neoterazolij) [5,5'di-C14]-BT (sinij tetrazolij). Vykhody kak dlya monotetrazoliya, tak i dlya ditetrazoliya dostatochno znachitel'ny i produkty mogut byt' polucheny s bol'shoj udel'noj aktivnost'yu. Stepen' chistoty obraztsov byla issledovana pri pomoshchi khromatograficheskoj bumagi. V solyakh ditetrazoliya bylo obnaruzheno nekotoroe kolichestvo primesej, chto pozvolilo vyvesti zaklyucheniya otnositel'no ikh struktury i kolichestva. Byl vyrabotan metod mechennykh C14 solej ditetrazoliya vysokoj chistoty. Obrazovanie formazana, predshestvennika solej tetrazoliya, prokhodit cherez neustojchivuyu promezhutochnuyu stadiyu strukturnogo tipa tetrazona, bystro peregruppiruyushchegosya v shchelochnoj srede, chtoby dat' formazan. V podkhodyashchikh usloviyakh promezhutochnyj tetrazon mozhet byt' otdelen. Ispol'zovanie mechennogo C14 benzal'degidfenilgidrazoniya pozvolilo issledovat' ehtu peregruppirovku i proverit' ukazyvaemuyu mezhmolekulyarnuyu strukturu. (author)
[en] A new method is proposed for the determination of small amounts of zinc in metallic cadmium with Neotetrazolium chloride (NTC). It is based on the formation of ionic associations with the thiocyanate complexes of cobalt and of zinc. The blue cobalt ion associate is more soluble in water and organic solvents than the zinc ion associate. This characteristic leads to the conversion of the cobalt association into the zinc association, if zinc is added to the solution of the cobalt ion association. The concentration of the zinc introduced is proportional to the decrease in the light absorption of the cobalt ion association. Cadmium does not interfere with the determination. The smallest zinc content in cadmium that can still be determined is 0.003%. The relative standard deviation of the method is +-3.35%. (author)
[en] This study investigated the effects of millimeter wave (MMW) irradiation with a wide range of frequencies on the proliferation and activity of normal human skin fibroblast (NB1RBG) and human glioblastoma (A172) cells. Very few studies have focused on low-power, long-term irradiation of cells with a widely tunable source. Our research examined non-thermal effects on cells exposed to radiation at low power with tunable frequencies from 70 GHz to 300 GHz. A widely tunable MMW source was set within a cell culture incubator. To avoid the effect of heat generation due to irradiation, the intensity was maintained below 10 μW and the device was arranged such that the irradiation came from underneath the cells. Irradiation was performed by sweeping from 70 GHz to 300 GHz in 1.0 GHz steps. The MMW source was positioned 100 mm away from the container in which the cells were cultured. Cells were exposed to MMWs for either 3, 70 or 94 h. Measurements of cell proliferation were made using the alternating current measurement method. We found no difference in proliferation between cells exposed to MMWs and unexposed cells. A colorimetric method using novel tetrazolium compound: MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt] was used for cell activity and cytotoxicity assays. We found no difference in cellular activity or toxicity between MMW-exposed cells and sham cells. Our study thus found no non-thermal effect as a result of exposure of cells to 70 GHz to 300 GHz of radiation.
[en] The use of tetrazolium salts for extraction, spectrophotometric and potentiometric determination of various elements and ions is described. The optimum conditions for extraction of tetrazolium ion-associated complexes are analysed. Chromogenic and other systems derived from tetrazolium salts and their applications in the analysis of industrial and natural samples are discussed.
[en] The measurement of radiation survival using a clonogenic assay, the established standard, can be difficult and time consuming. In this study, We have used the MTT assay, based on the reduction of a tetrazolium salt to a purple formazan precipitate by living cells, as a substitution for clonogenic assay and have examined the optimal condition for performing this assay in determination of radiation sensitivity. Four human cancer cell lines - PCI-1, SNU-1066, NCI-H63O and RKO cells have been used. For each cell line, a clonogenic assay and a MTT assay using Premix WST-1 solution, which is one of the tetrazolium salts and does not require washing or solubilization of the precipitate were carried out after irradiation of 0, 2, 4, 6, 8, 10 Gy, For clonogenic assay, cells in 25 cm2 flasks were irradiated after overnight incubation and the resultant colonies containing more than 50 cells were scored after culturing the cells for 10-14 days, For MTT assay, the relationship between absorbance and cell number, optimal seeding cell number, and optimal timing of assay was determined. Then, MTT assay was performed when the irradiated cells had regained exponential growth or when the non-irradiated cells had undergone four or more doubling times. There was minimal variation in the values gained from these two methods with the standard deviation generally less than 5%, and there were no statistically significant differences between two methods according to t-test in low radiation dose (below 6 Gy). The regression analyses showed high linear correlation with the R2 value of 0.975-0.992 between data from the two different methods. The optimal cell numbers for MTT assay were found to be dependent on plating efficiency of used cell line. Less than 300 cells/well were appropriate for cells with high plating efficiency (more than 30%). For cells with low plating efficiency (less than 30%), 500 cells/well or more were appropriate for assay. The optimal time for MTT assay was alter 6 doubling times for the results compatible with those of clonogenic assay, at least after 4 doubling times was required for valid results. In consideration of practical limits of assay (12 days, in this study) cells with doubling time more than 3 days were inappropriate for application. In conclusion, it is found that MTT assay can successfully replace clonogenic assay of tested cancer cell lines after irradiation only if MTT assay was undertaken with optimal assay conditions that included plating efficiency of each cell line and doubling time at least
[en] A composite micelle of ionic complex encapsulated into poly(ethylene glycol)-poly(d,l-lactide) (PEG–PLA) di-block copolymeric micelles was used for protein drug delivery to improve its pharmacokinetic performance. In this study, recombinant human erythropoietin (rhEPO, as a model protein) was formulated with lysine into composite micelles at a diameter of 71.5 nm with narrow polydispersity indices (PDIs < 0.3). Only a trace amount of protein was in aggregate form. The zeta potential of the spherical micelles was ranging from −0.54 to 1.39 mv, and encapsulation efficiency is high (80 %). The stability of rhEPO was improved significantly in composite micelles in vitro. Pharmacokinetic studies in rats showed significant, enhanced plasma retention of the composite micelles in comparison with native rhEPO. Areas under curve (AUCs) of the rhEPO released from the composite micelles were 4.5- and 2.3-folds higher than those of the native rhEPO and rhEPO-loaded PEG–PLA micelle, respectively. In addition, the composite micelles exhibited good biocompatibility using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay with human embryonic kidney (HEK293T) cells. All these features are preferable for utilizing the composite micelles as a novel protein delivery system
[en] Integrin α5β1 immobilized on a ProteoChip was used to screen new antagonistic peptides from multiple hexapeptide sub-libraries of the positional scanning synthetic peptide combinatorial library (PS-SPCL). The integrin α5β1-Fibronectin interaction was demonstrated on the chip. A novel peptide ligand, A5-1 (VILVLF), with high affinity to integrin α5β1 was identified from the hexapeptide libraries with this chip-based screening method on the basis of a competitive inhibition assay. A5-1 inhibits the integrin-fibronectin interaction in a dose-dependent manner (IC50; 1.56 ± 0.28 μM. In addition, it inhibits human umbilical vein endothelial cell proliferation, migration, adhesion, tubular network formation, and bFGF-induced neovascularization in a chick chorioallantoic membrane. These results suggest that A5-1 will be a potent inhibitor of neovascularization.
[en] Objective to assess the neutrophil function in thalassemia major (TM)patients and compare it with the control group and to recognize its relevantfactors. This was a retrospective cohort study, which was carried out fromOctober 2007 to February 2008 in the Thalassemia research Center in Boo AliSina Hospital in Sari, Mazandaran, North of Iran. The study populationconsisted of TM patients in Boo Ali Sina Teaching Hospital. The method ofsampling in the case group was systematic and it was target based in thecontrol group. The sample size determined was based on previous studies.Thalassemia major was diagnosed based on hemoglobin electrophoresis (casegroup). The control group was their brothers and sisters, who had +-5 yearsof age difference and were of the same gender as the patients. Datacollection was based on interview, investigating demographic characteristicsand also obtaining medical information from medical records of the patients.The neutrophil function was by performing nitroblue tetrazolium (NBT)reduction test. The test was carried out on both groups and the data wereanalyzed by software using SPSS version 13.0. In this study, 39 patients and39 healthy controls were compared. The average age of the patients was21.6+-5.3 years and it was 22.4+-5.1 years in healthy controls (p=0.7). Therewas a significant correlation between the test's results and the patients age(p=0.008). The rate of impaired NBT results in the patients was 36%, while itwas 10% in controls, which were significantly different. The neutrophilactivity based on NBT test was 89.9+-11.6% in the case group and 93.7+-2.51%in the control group (p=0.025). This study indicates that neutrophil activityin thalassemia patients was significantly lower, compared to the normalcontrol group, especially in young patients. Based on the results, evaluationof neutrophil function and pyogenic infections in TM patients seemsnecessary. (author)