Neotetrazolium Chloride Research Articles

Extractive Spectrophotometric Determination and Theoretical Investigations of Two New Vanadium(V) Complexes.

Two new vanadium (V) complexes involving 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR) and tetrazolium cation were studied. The following commercially available tetrazolium salts were used as the cation source: tetrazolium red (2,3,5-triphenyltetrazol-2-ium;chloride, TTC) and neotetrazolium chloride (2-[4-[4-(3,5-diphenyltetrazol-2-ium-2-yl)phenyl]phenyl]-3,5-diphenyltetrazol-2-ium;dichloride, NTC). The cations (abbreviated as TT+ and NTC+) impart high hydrophobicity to the ternary complexes, allowing vanadium to be easily extracted and preconcentrated in one step. The complexes have different stoichiometry. The V(V)-HTAR-TTC complex dimerizes in the organic phase (chloroform) and can be represented by the formula [(TT+)[VO2(HTAR)]]2. The other complex is monomeric (NTC+)[VO2(HTAR)]. The cation has a +1 charge because one of the two chloride ions remains undissociated: NTC+ = (NT2+Cl-)+. The ground-state equilibrium geometries of the constituent cations and final complexes were optimized at the B3LYP and HF levels of theory. The dimer [(TT+)[VO2(HTAR)]]2 is more suitable for practical applications due to its better extraction characteristics and wider pH interval of formation and extraction. It was used for cheap and reliable extraction-spectrophotometric determination of V(V) traces in real samples. The absorption maximum, molar absorptivity coefficient, limit of detection, and linear working range were 549 nm, 5.2 × 104 L mol-1 cm-1, 4.6 ng mL-1, and 0.015-2.0 μg mL-1, respectively.

Specific features of tetranitrotetrazolium blue chloride as an extraction reagent for iron(III)

A liquid-liquid extraction-chromogenic system containing Fe(III), 4-(2-thiazolylazo)resorcinol (TAR), [3,3’-(3,3’-dimetoxy-4,4’-biphenylene)bis[2,5-di(4-nitrophenyl)-2H-tetrazolium] chloride (tetranitro-tetrazolium blue chloride, TNBT), water, and chloroform was studied and compared with similar systems containing such ditetrazolium salts (DTS), as neotetrazolium chloride (NTC), blue tetrazolium chloride, and nitro blue tetrazolium chloride. The results show that the complex formed in the Fe(III)–TAR–TNBT system is of different composition (1 : 3 : 2 vs. 1 : 2 : 1) and has better extraction-spectrophotometric characteristics (fraction extracted is 98.6 % and molar absorptivity, 7.8 × 104 dm3 mol–1 cm–1 at λ = 495 nm). The proposed formula of the complex is (TNBT+)[FeIII(TAR2–)2]·{(TNBT+)(HTAR–)}, where TNBT is in the monocationic form. The geometry optimization for TNBT and NTC–the DTS, which does not contain nitro- and methoxy groups, was performed by the Restricted Hartree–Fock (RHF) method with the 3-21G* basis set. The obtained results (ground-state structures and total atomic charges) for TNBT, TNBT+, TNBT2+, NTC, and NT2+ were compared and discussed.

Study on the complex formation of anionic chelates of Co(II)–4-(2-thiazolylazo)resorcinol with ditetrazolium cations

The ion-associated complexes formed between anionic chelates of Co(II)–4-(2-thiazoly-lazo)resorcinol (TAR) and cations of ditetrazolium salts (DTS)—Nitro Blue Tetrazolium Chloride (NBT), Blue Tetrazolium chloride (BTC) and Neotetrazolium chloride (NTC)—in the liquid-liquid extraction system Co(II)–TAR–DTS–H2O–CHCl3 were studied. The optimum conditions for the formation and the solvent extraction of the ternary ion-associated complexes Co–TAR–DTS were found. The molar ratio of the components in the associates was determined by independent methods. Based on this, a reaction scheme and a general formula of the complexes were suggested. The extraction equilibria were investigated quantitatively. The following key constants were calculated: association constant, distribution constant, extraction constant and recovery factor. The validity of Beer’s law was checked and some analytical characteristics were calculated. Based on the obtained results and the lower price of the ditetrazolium salt BTC compared with NBT, the ion-associated complex of Co–TAR–BTC can be successfully used for determining of cobalt in alloys, biological, medical and pharmaceutical formulations.

Ion-association between some ditetrazolium cations and anions originated from 4-(2-thiazolylazo)resorcinol or 4-(2-pyridylazo)resorcinol

Ion-associates between cations originating from ditetrazolium salts (DT: Neotetrazolium chloride (NT), Blue Tetrazolium chloride (BT), Nitro Blue Tetrazolium chloride (NBT), and Tetranitro Blue Tetrazolium chloride (TNBT)) and anions originating from azo compounds (AC: 4-(2-pyridylazo)resorcinol (H2PAR) and 4-(2-thiazolylazo)resorcinol (H2TAR)) were studied by water-chloroform extraction and spectrophotometry. Some key characteristics of the extracted compounds were determined. They can be expressed by different formulae depending on the ACs and DTs used: (1) (DT + )(HPAR - ) (for DT = BT, NBT or TNBT); (2) (DT 2+ )(HTAR - )2 (for DT = BT, NBT or TNBT); and (3) (DT + )2(HAC - )2 (for DT = NT).

Liquid-liquid extraction of ion-association complexes of cobalt(II)-4-(2-pyridylazo)resorcinol with ditetrazolium salts

The formation and liquid-liquid extraction of ion-association complexes between Co(II)-4-(2-Pyridylazo)resorcinol (PAR) anionic chelates and cations of three ditetrazolium chlorides were studied: Blue Tetrazolium chloride (BTC), Neotetrazolium chloride (NTC) and Nitro Blue Tetrazolium chloride (NBT). The optimum conditions for the formation and solvent extraction of the ion-association comlpex chelates were determined. It has been found that in the systems of Co(II)-PAR-DTS, the reactants are reacted in molar ratios 1:2:1 and the general formula of complexes was suggested. The extraction equilibria were investigated and quantitatively characterized by the equilibrium constants and the recovery factors. The analytical characteristics of the complexes were calculated.

Ternary complexes of vanadium(IV) with 4-(2-pyridylazo)-resorcinol (PAR) and ditetrazolium chlorides (DTC)

Abstract Complex formation and liquid-liquid extraction have been studied for ternary complexes of vanadium(IV) with 4-(2-pyridylazo)-resorcinol (PAR) and ditetrazolium chlorides (DTC) in a water-chloroform medium. The specific ditetrazolium compounds investigated were i) 3,3′-(4,4′-biphenylene)-bis(2,5-diphenyl-2H-tetrazolium) chloride (Neotetrazolium chloride, NTC); ii) 3,3′-(3,3′-dimetoxy-4,4′-biphenylene)-bis(2,5-diphenyl-2H-tetrazolium) chloride (Blue Tetrazolium chloride, BTC); and iii) 3,3′-(3,3′-dimetoxy-4,4′-biphenylene)-bis[2-(4-nitrophenyl)-5-phenyl-2H-tetrazolium] chloride (Nitro Blue Tetrazolium chloride, NBT). Molar absorptivity coefficients and the composition of the complexes have been calculated. Association constants (β) have also been obtained for the interactions between the vanadium(IV) — PAR anionic chelates [VO(PAR)2]2− (I) and [VO(OH)2(PAR)2]4− (II), and ditetrazolium cations (DT2+). Some special features of NBT as an extraction-spectrophotometric reagent for vanadium(IV) have been discussed. Unlike NTC and BTC which form complexes with both I and II, NBT associates only with II. The pH interval for complete extraction of (NBT2+)2[VO(OH)2(PAR)2] is broader and allows work at lower pH values the other ion-associates of V(IV,V)-PAR that were studied. NBT is -therefore the appropriate reagent both for direct V(IV) determination and for V(IV)/V(V) separation. Some additional characteristics for the V(IV)-PAR-NBT-water-chloroform system have been determined: extraction constant, distribution constant, recovery factor, limit of detection and limit of quantification. Beer’s law is valid up to 1.4 μg mL−1 vanadium(IV) with molar absorptivity coefficient of 3.55×104 L mol−1 cm−1 at λmax=559 nm.

UV dosimeters based on neotetrazolium chloride

A novel UV dosimeter is described comprising a tetrazolium dye, neotetrazolium chloride (NTC), dissolved in a film of polymer, polyvinyl alcohol (PVA). The dosimeter is pale yellow/colourless in the absence of UV light, and turns red upon exposure to UV light. The spectral characteristics of a typical UV dosimeter film and the mechanism through which the colour change occurs are detailed. The NTC UV dosimeter films exhibit a response to UV light that is related to the intensity and duration of UV exposure, the level of dye present in the films and the thickness of the films themselves. The response of the dosimeter is temperature independent over the range 20–40 °C and, like most UV dosimeters, exhibits a cosine-like response dependence upon irradiance angle. The introduction of a layer of a UV-screening compound which slows the rate at which the dosimeter responds to UVR enables the dosimeter response to be tailored to different UV doses. The possible use of these novel dosimeters to measure solar UV exposure dose is discussed.

EFFECT OF COCAINE ON MITOCHONDRIAL ELECTRON TRANSPORT CHAIN EVALUATED IN PRIMARY CULTURES OF NEONATAL RAT MYOCARDIAL CELLS AND IN ISOLATED MITOCHONDRIAL PREPARATIONS

Cardiotoxicity is commonly associated with cocaine abuse. Previous studies have indicated that cocaine alters myocardial mitochondrial function. This study was undertaken to investigate the effect of cocaine on activity of the mitochondrial electron transport chain in cultures of neonatal rat cardiomyocytes and in isolated myocardial mitochondria. Cocaine concentrations (10−5 to 10−3 M) were used, and these concentrations have been reported in human cocaine users and are within a similar range of cocaine concentrations used in studies in vivo. After 24 hr treatment of cocaine, there was a slight increase in lactate dehydrogenase leakage in the cells treated with cocaine (10−3 M). Reduction of tetra zolium compounds, neotetrazolium chloride (NTC) and triphenyltetrazolium chloride (TTC) was analyzed in intact cells to assess activity of the mitochondrial electron transport chain. Cocaine (10−3 M) did not significantly change TTC and NTC reduction. In isolated mitochondria, cocaine (10−3 M) significantly inhibited glutamate/malate-mediated respiration. These data suggest that cocaine at high concentrations may inhibit complex I of the mitochondrial electron transport chain of myocardial cells.

Neotetrazolium chloride: a new reagent for spectrophotometric determination of manganese

The interaction of Mn(VII) and the Neotetrazolium chloride has been examined. The ion-associate formed is extracted into 1,2di-chloroethane. The optimum conditions have been established. The molar absorptivity of the complex is (9.1±0.08)×10 5 l mol −1 cm −1. The sensitivity of the method is 6.04×1010 −5 μg cm −2. It is possible to extract and determine manganese in the presence of large number of cations and anions. The characteristic values for the extraction and the aqueous phase equilibria were determined: extraction constant K ex=3.21×10 9, distribution constant K D=33 and association constant β=9.72×10 7. The method is applicable to analysis of soils and steels.

Neotetrazolium Chloride — A New Analytical Reagent for Determination of Chromium

ABSTRACT The optimum conditions for the formation of an ion-associate between chlorochromate ion and Neotetrazolium chloride (NTC) were found. The molar ratio NTC:Cr in the extracted ion-associate was found to be 1:2. Beer's law was obeyed in the range 0.05 – 1.5 μg ml−1 Cr(VI). The molar absorptivity determined at 255 nm, was 3.12±0.06 × 104 L mol−1 cm−1. The method was used for determination of chromium in steels, various types of soils and plants.

Investigation of the extraction equilibria in the system hexachloridorhenate(IV)-neotetrazolium chloride-dichloroethane-water

The neotetrazolium hexachloridorhenate(IV) (NTReCl 6) has been synthesized and its composition checked. The optimum conditions for the extraction of NTReCl 6 with dichloroethane have been established. The recovery factor for one-fold extraction is R = 74%. The distribution constant, K D, extraction constant, K ex, and ion-association constant, β, have been determined. Neotetrazolium chloride was found to be suitable reagent for extraction-spectrophotometric determination of rhenium(IV) ( ϵ NTReCl 6 = 3.42 ± 0.20 × 10 4 M −1 cm −1).

THE USE OF TETRAZOLIUM SALTS TO DETERMINE SITES OF DAMAGE TO THE MITOCHONDRIAL ELECTRON TRANSPORT CHAIN IN INTACT CELLS FOLLOWING in vitro: PHOTODYNAMIC THERAPY WITH PHOTOFRIN II

A method is described utilizing the tetrazolium salts neotetrazolium chloride (NTC), triphenyltetrazolium chloride (TTC), C,N-diphenyl-N'-4,5-dimethylthiazol-2-yltetrazolium bromide (MTT) and various substrates to elucidate damage to the mitochondrial electron transport chain of intact cells following in vitro photodynamic therapy (PDT). Using this methodology, a portion of the dark toxicity manifested by Photofrin II (PII) was found to occur prior to entry of electrons into the transport chain through Complex I, as evidenced by the fact that the inhibition of MTT reduction was reversible by the addition of malic acid to the culture media. A second site of dark toxicity was found to be Complex IV (cytochrome oxidase). After photoirradiation of the cells, Complex I was found to be affected since malic acid could no longer reverse the inhibition of MTT reduction but it could be reversed by the addition of succinic acid, whose electrons enter the transport chain at Complex II. A second and more sensitive site of photoirradiation damage was found to be Complex IV. A region near cytochrome C was also affected by photoirradiation but appreciably less so than noted for Complexes I and IV. A kinetic analysis of MTT and TTC reduction following photoirradiation indicated that MTT reduction was sustained at a normal rate for 1 h after which it slowed down and eventually plateaued. In contrast, TTC reduction was found to be inhibited almost immediately indicating Complex IV is extremely susceptible to photoirradiation damage. Compared to other assays of mitochondrial function requiring subcellular fractionation, the use of tetrazolium salts is simpler to perform and can be done using physiologically relevant conditions.

THE USE OF TETRAZOLIUM SALTS TO DETERMINE SITES OF DAMAGE TO THE MITOCHONDRIAL ELECTRON TRANSPORT CHAIN IN INTACT CELLS FOLLOWING in vitro PHOTODYNAMIC THERAPY WITH PHOTOFRIN II

Abstract A method is described utilizing the tetrazolium salts neotetrazolium chloride (NTC), triphenyltetrazolium chloride (TTC), C,N‐diphenyl‐N'‐4,5‐dimethylthiazol‐2‐yltetrazolium bromide (MTT) and various substrates to elucidate damage to the mitochondrial electron transport chain of intact cells following in vitro photodynamic therapy (PDT). Using this methodology, a portion of the dark toxicity manifested by Photofrin II (PII) was found to occur prior to entry of electrons into the transport chain through Complex I, as evidenced by the fact that the inhibition of MTT reduction was reversible by the addition of malic acid to the culture media. A second site of dark toxicity was found to be Complex IV (cytochrome oxidase). After photoirradiation of the cells, Complex I was found to be affected since malic acid could no longer reverse the inhibition of MTT reduction but it could be reversed by the addition of succinic acid, whose electrons enter the transport chain at Complex II. A second and more sensitive site of photoirradiation damage was found to be Complex IV. A region near cytochrome C was also affected by photoirradiation but appreciably less so than noted for Complexes I and IV. A kinetic analysis of MTT and TTC reduction following photoirradiation indicated that MTT reduction was sustained at a normal rate for 1 h after which it slowed down and eventually plateaued. In contrast, TTC reduction was found to be inhibited almost immediately indicating Complex IV is extremely susceptible to photoirradiation damage. Compared to other assays of mitochondrial function requiring subcellular fractionation, the use of tetrazolium salts is simpler to perform and can be done using physiologically relevant conditions.

Ultrastructural changes in the appendix of the Sauromatum guttatum inflorescence during anthesis

The ultrastructure of the epidermal and sub-epidermal cells of the appendix of the Sauromatum guttatum inflorescence reveals developmental changes during anthesis. These changes precede, and probably make possible, heat and odor production. Two days before D-day (the day of heat production and inflorescence-opening) the mitochondria of the epidermis divide; apparent division of the amyloplasts was observed at the same time. The presence of lipid bodies and peroxisomes in the epidermis was clearly evident. On D-day, the epidermis becomes a continuous layer in which the cell walls separating two adjacent cells disappear. At the same time, in the sub-epidermal cells, the mitochondria and the amyloplasts undergo division. The mitochondria become electron-dense, and their DNA is clearly visible. On that day, lipids as well as starch are being depleted. The peroxisomes change in structure every day, from D-2 to D-day. It has also been demonstrated by histochemical techniques that during anthesis the activity of cytochrome c oxidase (3,3-diaminobenzidine as a substrate) decreases whereas the activity of NADH dehydrogenase [tetrazolium salts: nitro-blue tetrazolium chloride (NBT) or neotetrazolium chloride (NT) in the presence of NADH], increases. Oxygen consumption of isolated mitochondria from the D-day appendix was inhibited in the presence of the two tetrazolium salts to a different degree: oxidation of NADH in the presence of NBT was the most sensitive to inhibition, more so than the oxidation of malate and succinate. NT was less effective as an inhibitor in the presence of those three respiratory substrates.

Spectrophotometric method for the determination of carbidopa using neotetrazolium chloride.

A new high-sensitive spectrophotometric method for the determination of microquantities of carbidopa is described. The method is based on the reduction of neotetrazolium chloride by carbidopa in an alkaline ethanolic medium. The formazan formed exhibits an absorption maximum at lambda = 507 nm, with an apparent molar absorptivity of epsilon = 6.63 x 10(4) M-1 cm-1 and a corresponding Sandell's sensitivity of 3.68 ng cm-2. Beer's law is obeyed over the range of 0.10-6.0 micrograms mL-1 while the optimum concentration range is 0.125-5.0 micrograms mL-1. The regression line equation was calculated as: A = 0.271C + 0.0023 with a correlation coefficient of 1.0000 (n = 28). The accuracy and the precision of the method were considered as very satisfactory. The results obtained from the determination of carbidopa using both the described procedure and the corresponding USP. XXII and BP 1988 clinical methods were statistically compared by means of Student's t-test as well as by the variance ratio F-test, and no significant difference was observed.

A quantitative histochemical study of NADPH-ferrihemoprotein reductase activity.

A quantitative histochemical assay for NADPH-ferrihemoprotein (P450) reductase had been developed. For optimal activity, it is necessary to use a relatively electropositive tetrazolium salt such as neotetrazolium chloride as the final acceptor. The apparent Km of the reaction is 0.83 mM. Its specificity has been proven in two ways: (i) activity is increased selectively in the pericentral zone of liver from rats treated with phenobarbitone, an inducer of the reductase, though not in liver of rats injected with 3-methylcholanthrene, which induces NAD(P)H dehydrogenase; (ii) it is competitively inhibited by NADP+ (Ki = 1.50 mM) though unaffected by dicumarol, an inhibitor of NAD(P)H dehydrogenase activity. An NADP+ concentration ten times greater than the substrate concentration inhibits the histochemical reaction and the reaction in a microsomal fraction assayed biochemically to the same degree (70% inhibition). The amount of inhibition is independent of temperature, of the zone of the acinus and of the treatment of the animal. Continuous microdensitometric monitoring of the reaction product as it is formed has shown that the specific reaction is linear with incubation up to 10 min, thus allowing end-point measurements to be used for cytophotometric analysis.

Spectrophotometric Determination of Cobalt(II) with Thiocyanate. A Modification for Increasing Sensitivity and Selectivity

Abstract The ion association complex formed between [Co(SCN)4]2− and 3,3′-(1,1′-biphenyl-4,4′-diyl)bis[2,5-diphenyl-2H-tetrazolium] dichloride, commercially known as neotetrazolium chloride, has been extracted into isobutyl methyl ketone and used for the photometric determination of 2.5–9.8 μg cm−3 cobalt at pH 3.5–5.0 (acetate buffer). Sandell’s sensitivity of the method (0.02 μg cm−2) is better than most of the other thiocyanate methods known so far. Interference of diverse ions has been studied. Using the higher tolerances of anions, many cations interfering in the other thiocyanate methods have been masked, thus making the present procedure more selective. The method has been applied to wire alloys.

Spectrophotometric determination of molybdenum in steels with pyrocatechol and neotetrazolium chloride

A method is described for the spectrophotometric determination of molybdenum in alloys, which is based on the formation of an ion association complex between the molybdenum pyrocatechol anion, [MoO2Cl2-(catechol)]2–, and neotetrazolium chloride. The results presented show that the method is more selective than other previously used catechol-based procedures.

Spectrophotometric determination of cobalt(II) based on the ion-pair of tetrathiocyanatocobaltate(II) with neotetrazolium chloride

The ion-pair formed between tetrathiocyanatocobaltate(II) and [3,3′-(4,4′- biphenylene)bis(2,5-diphenyl)]-2H-tetrazolium chloride (neotetrazolium chloride) can be extracted into 4-methylpentan-2-one and used for the spectrophotometric determination of cobalt (2.5–9.8 μg ml−1) at pH 3.5–5.0. The Sandell sensitivity of the method is 0.02 μg Co cm−2. With suitabte masking, the method is quite selective and is applicable to nickel wire alloys.

Characteristics of an unclassified Mycobacterium species isolated from patients with Crohn's disease.

The characteristics of an unclassified Mycobacterium sp. isolated from three patients with Crohn's disease are presented. The organism is extremely fastidious and mycobactin dependent and may require up to 18 months of incubation for primary isolation. Colony morphology is rough. Characteristics are unlike those of any presently defined species. The isolates produced postive niacin, catalase, and 2-week arylsulfatase reactions and were susceptible to neotetrazolium chloride (1:40,000), streptomycin (2 micrograms/ml), and rifampin (0.25 micrograms/ml). Chromogenicity, nitrate reduction, quantitative catalase, Tween hydrolysis, urease, tellurite reduction, pyrazinamidase, and 3-day arylsulfatase tests were negative, and the isolates were resistant to thiophene-2-carboxylic acid hydrazide (10 micrograms/ml) and isoniazid (10 micrograms/ml). Optimum growth in broth was determined to be in 7H9 medium with Dubos oleic albumin complex, Tween 80, and mycobactin J at 37 degrees C without CO2 or agitation and in low medium depth. This Mycobacterium sp. may be a subspecies or biovariant of Mycobacterium paratuberculosis, or it may represent a new species of Mycobacterium. It is suggested that this Mycobacterium sp. may play an etiological role in some cases of Crohn's disease.