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PubMedDate not supplied

Peroxyoxalate chemiluminescence detection of condensates of malondialdehyde with thiobarbituric acids using a flow system.

The peroxyoxalate chemiluminescence(CL) detection method for the evaluation of the CL intensity of malondialdehyde(MDA) condensates with seven 2-thiobarbituric acid derivatives is described. The method consists of a flow injection technique together with a CL detection system using bis(2,4,6-trichlorophenyl) oxalate(TCPO) and hydrogen peroxide as chemiluminogenic reagents. Linear correlations between CL intensity and concentration are obtained for pmol levels of condensates. Among the condensates, 1,3-diethyl-2-thiobarbituric acid(DETBA)-MDA shows the largest CL intensity. High performance liquid chromatography (HPLC)/CL detection of DETBA-MDA and 1,3-diphenyl-2-thiobarbituric acid(DPTBA)-MDA using a mixture of TCPO and hydrogen peroxide in acetonitrile as a postcolumn reagent solution is also described. The detection limits for DETBA-MDA and DPTBA-MDA are 20 and 200 fmol, respectively, per 20 microL injection at a signal-to-noise ratio of 2. This HPLC/CL detection system was applied to the determination of MDA in rat brains by using DETBA as a fluorescent derivatizing reagent.

Animals↗
PubMed1975

Novel interference in thiobarbituric acid assay for lipid peroxidation.

The thiobarbituric acid test for lipid peroxidation, when applied to a mixture of acetaldehyde and sucrose, produces a 532 nm aborbing chromogen which is indistinguishable from that formed by malonaldehyde and thiobarbituric acid. Unless special procedures are adopted to correct for this effect, the combined action of acetaldehyde and sucrose interferes seriously with the assay of lipid peroxidation reactions, notably those implicated in alcohol-induced liver injuries. However, this unusual thiobarbituric acid effect also can be used as a sensitive method for the detection of acetaldehyde.

Acetaldehyde↗
PubMed1984

Changes in superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase activities and thiobarbituric acid-reactive products levels in early stages of development in dystrophic chickens.

Cu-Zn superoxide dismutase, Mn superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase activities and thiobarbituric acid-reactive products were assayed in the superficial pectoral muscles of genetically dystrophic chickens (line 413) and their controls (line 412) 1, 2, and 4 weeks, and 4 months after hatching. In control chickens, all these enzyme activities declined as they grew older. In dystrophic chickens, all these enzyme activities were significantly elevated at all stages of development studied, and their developmental time courses were quite different from those in the controls. Thiobarbituric acid-reactive products were also significantly elevated in dystrophic chickens after 2 weeks of age. Invasion of macrophages and lipid cells were not manifest until 4 weeks after hatching in the dystrophic chickens studied. Therefore, observed abnormalities were considered to represent biochemical pathologies within muscle cells. Increased activities of the enzymes which are responsible for the regulation of active oxygen species and the elevated thiobarbituric acid-reactive products would indicate the presence of increased turnover of those active oxygen species. These findings indicated that active oxygen species were playing a significant role in the pathogenesis of muscular dystrophies. The possible mechanisms of cellular damage by active oxygen species are discussed.

Animals↗
PubMed2004

Preventing in vitro lipoperoxidation in the malondialdehyde-thiobarbituric assay.

The malondialdehyde-thiobarbituric acid assay is widely used to study lipid peroxidation. Among the various methods used to perform the assay, the most widely accepted is the quantification of malondialdehyde using the thiobarbituric acid reaction, followed by reversed-phase chromatography. However, unacceptable results may be obtained as malondialdehyde can be produced in vitro. To study the conditions that inhibit in vitro lipid peroxidation, malondialdehyde levels were measured in cultured cells using different concentrations of butylated hydroxytoluene, EDTA or a combination of both. Butylated hydroxytoluene alone inhibits in vitro lipid peroxidation effectively. EDTA reduces artificially produced malondialdehyde, but not totally. Finally, the combination of EDTA and butylated hydroxytoluene does not improve the results obtained using butylated hydroxytoluene alone. The conclusion is that in the malondialdehyde-thiobarbituric acid assay it is necessary to add an inhibitor of the in vitro lipid peroxidation and assay the necessary concentration depending on the specimen used.

Butylated Hydroxytoluene↗
PubMed1988

Inaccuracy in measuring glycated albumin concentration by thiobarbituric acid colorimetry and by boronate chromatography.

We compared thiobarbituric acid colorimetry and boronate chromatography for measuring glycation of serum proteins. With 14C-glycated human albumin as a test material, both methods were acceptably linear and precise. However, comparable estimates (mmol/L) of albumin glycation ranged from 0.22 for thiobarbituric acid to 0.05 for boronate, representing yields relative to [14C]glycosylprotein of 42% and 10%, respectively. The low yield with thiobarbituric acid was corroborated independently on the basis of kinetic differences between the reactions of fructose standards and of glycosylprotein, leading to underestimation of glycosylprotein concentration. The lower estimate of glycosylprotein by boronate chromatography was related to an apparent requirement for two [14C]glyco groups per albumin molecule to effect binding.

Chromatography↗
PubMed1981

Syntheses and pharmacological analysis of new derivatives of tetrahydro-[1,3]-thiazine and 2-thiobarbituric acid.

Three groups of compounds:1,3-thiazine derivatives, 2-thiobarbituric acid derivatives and noncyclic thioureide were obtained as a result of condensation of some N, N1-derivatives of thiocarbamide and malonyl dichlorides, depending on the reaction conditions and chemical character of reagents. It was observed that the substituents beside nitrogen atoms of thiocarbamides, the kind of acid chloride and reaction conditions influenced the course of reaction. The structure of the newly synthesized compounds was proved by the analysis of PMR spectrum and the interpretation of IR spectrum. In the performed pharmacological examination immunotropic and anti-inflammatory activity of these compounds was determined. Among 1,3-thiazine derivatives, 5,5-diallyl-2-phenylimino-3-phenyl-2,3,4,5-tetrahydro-[1,3]-thiazine-4,6-dione and 5,5-diethyl-2-phenylimino-3-naphtyl-2,3,4,5-tetrahydro-[1,3]-thiazine-4,6-dione exhibited anti-inflammatory activity. The compounds also contained the immunotropic component, either stimulatory or suppressive, 2-thiobarbituric acid derivatives displayed stronger anti-inflammatory activity correlated mostly with the immunosuppressive activity. Some interdependence between chemical structure and biological activity in the group of the investigated 1,3-thiazines and 2-thiobarbituric acid derivatives was observed.

Animals↗
PubMed1992

Differential sensitivity of diabetic rat papillary muscles to negative inotropic effects of oxybarbiturates versus thiobarbiturates.

The negative inotropic effects of oxybarbiturates and thiobarbiturates were examined in papillary muscles isolated from streptozotocin-induced diabetic rats and in papillary muscles from age-matched control rats. The muscles from diabetic rats exhibited less negative inotropic responses to pentobarbital and secobarbital than the muscles from control rats. Conversely, the negative inotropic responses to thiopental and thiamylal were significantly enhanced in diabetic muscles. Differences in sensitivity to pentobarbital between control and diabetic muscles became less marked by treatment with ouabain or by lowering [Na+]o. Enhancement of the negative inotropic effect of thiamylal observed in diabetic muscles remained unchanged with these treatments. In both control and diabetic muscles, the negative inotropic effect of pentobarbital was completely reversed by increasing [Ca2+]o, but the effect of thiamylal was only partially reversed. These results suggest a difference in mechanism of action involved in establishment of the negative inotropic effects of oxybarbiturates vs thiobarbiturates. Oxybarbiturates appear to exclusively reduce the influx of extracellular Ca2+, whereas thiobarbiturates appear to affect Ca2+ movements at the Ca2+ storage sites in addition to the Ca2+ influx inhibition.

Animals↗
PubMed1999

Thiobarbituric acid reactive substances in patients with laryngeal cancer.

The purpose of this study was to measure the level of thiobarbituric acid reactive substances (TBARS), which are products of lipid peroxidation, as a reflection of oxidative status in 30 patients with laryngeal cancer. The TBARS were measured 1 day before surgery and 3 weeks after laryngectomy compared to 30 normal control subjects by the thiobarbituric acid (TBA) test using spectrophotometry. The TBARS levels were significantly elevated in patients with laryngeal cancer compared to the controls (18.4 +/- 3.13 mumol/l versus 7.75 +/- 1.9 mumol/l; P < 0.05). There were no differences in the TBARS levels in relation to T staging, N staging, or degree of differentiation. Among patients with laryngeal cancer smokers had slightly higher TBARS levels. Comparison of the paired observations of laryngeal cancer larynx before and after operation revealed a significant rise in the TBARS levels after laryngectomy. Tissue damage resulting from surgery is the most probable explanation for this rise. The state of altered lipid peroxidation detected in our patients might be related to a deficient antioxidant status. The role of antioxidants in the prevention of laryngeal cancer among high risk patients is worth studying.

Carcinoma, Squamous Cell↗
PubMed2001

Urinary thiobarbituric acid-reacting substances as potential biomarkers of intrauterine hypoxia.

BACKGROUND: Currently available clinical tools cannot accurately identify the extent of perinatal hypoxic injuries. During hypoxia, reactive oxygen species cause lipid peroxidation of cell membranes, yielding oxidation products that constitute thiobarbituric acid-reacting substances (TBARS). OBJECTIVE: To see if the concentrations of TBARS excreted in urine would be elevated during the first day of life in term and preterm infants following chronic hypoxia or acute asphyxia. DESIGN: Thiobarbituric acid-reacting substances levels were measured by a spectrophotometric assay in urine samples collected from term and near-term (>/= 34 weeks gestation, n = 22), and preterm (<34 weeks gestation, n = 52) infants on the first day of life. PATIENTS: Infants were admitted to the St Peter's University Hospital (New Brunswick, NJ) neonatal intensive care unit from July 1997 to January 1999. Acute asphyxia was defined as umbilical cord blood pH values less than 7.05, or Apgar scores of less than 5 at 5 minutes. Chronic hypoxia was defined as intrauterine growth retardation or low birth weight (small for gestational age) associated with pregnancy-induced hypertension or reversal of umbilical arterial blood flow. RESULTS: Among term infants, urinary TBARS levels were significantly increased following acute asphyxia (P =.02). Levels of TBARS also tended to be elevated following chronic hypoxia. Urinary TBARS levels in term infants tended to be increased in those requiring mechanical ventilation (P =.05) or delivery room resuscitation (P =.15), as well as in those passing intrauterine meconium (P =.13) or having clinical evidence of hypoxic-ischemic encephalopathy (P =.24). CONCLUSIONS: The results show a correlation between elevated urinary TBARS levels in term and near-term infants, and perinatal hypoxia (as determined by low Apgar scores or umbilical cord blood acidosis). We speculate that TBARS concentrations may be useful as a biomarker for perinatal hypoxic injury in newborns. Further studies are needed to determine whether elevations in TBARS levels are better predictors of the extent of hypoxic injury than existing markers.

Asphyxia Neonatorum↗
PubMed2002

Enantioselective chromatography of alkyl derivatives of 5-ethyl-5-phenyl-2-thiobarbituric acid studied by semiempirical AM1 method.

Complexation of alkyl derivatives of 5-ethyl-5-phenyl-2-thiobarbituric acid (2-thiophenobarbital) enantiomers by beta-cyclodextrin was investigated by the AM1 method. The inclusion complexes of beta-cyclodextrin with neutral and anionic forms of these enantiomers have been modeled and energetically optimized. The chiral discrimination of enantiomers was analyzed in terms of differences in the interaction energies. The calculated interaction energies between each enantiomer of the investigated 2-thiobarbiturates and beta-cyclodextrin confirm the ability of beta-cyclodextrin to act as a mobile phase additive in reversed-phase HPLC to separate enantiomers by liquid chromatography and rationalize their order of elution.

Chromatography, High Pressure Liquid↗
PubMed1980

Complex formation between copper(II) and thiobarbiturates.

Complex formation between copper(II) and selected thiobarbiturates was investigated via spectrophotometric procedures with absolute methanol as the solvent. The composition of the complexes proved to be 1:2 metal-ligand. The formation constants were computed using different procedures, and the results were reproducible. The electronic absorption spectra of the selected thiobarbiturates were studied. Spectrophotometric determination of the drugs was investigated.

Chemical Phenomena↗
PubMed1993

Lipoprotein oxidation and measurement of thiobarbituric acid reacting substances formation in a single microtiter plate: its use for evaluation of antioxidants.

Transition metals catalyze free radical-mediated oxidation of lipids and lipoproteins. This process is currently studied because of its potential relevance to pathological processes like atherosclerosis. Formation of thiobarbituric acid-reacting substances from polyenoic fatty acids is frequently used to follow oxidation of lipids and plasma lipoproteins. We describe here how Cu(II)- and Fe(III)-catalyzed oxidation of human low density lipoprotein or soy bean phospholipids and the photometric evaluation of the thiobarbituric acid-reaching substances formed can be conducted in the same 96-well microtiter plate. The procedure showed a correlation of 0.98 with conventional two-stage fluorimetric and spectrophotometric methods and also showed better reproducibility. The plate method can handle up to one plate per hour with considerably less labor than the test tube assays. The plate procedure required small volumes of diluted samples of lipoproteins lipids and reagents. The method was suitable for testing the concentration-dependent antioxidant potency of substances like probucol, butylated hydroxytoluene, and alpha-tocopherol. The method can also be used to follow the kinetics of oxidation of lipoproteins.

Antioxidants↗
PubMed1989

A modification of the thiobarbituric acid reaction.

A simple modification of the thiobarbituric acid reaction, which removes nonspecific chromogenic reaction products, involves incubation at room temperature for 16-20 hr and a column chromatographic step. The chromogen-concentrating capacity of the latter step is useful for determination of low concentrations of thiobarbituric acid-reactive materials in biological preparations.

Humans↗
PubMed1993

The urinary excretion of thiobarbituric acid reactive substances and malondialdehyde by normal adult males after consuming a diet containing salmon.

In this study we investigated the output of thiobarbituric acid reactive substances (TBARS) and malondialdehyde (MDA), as thiobarbituric acid (TBA)-MDA adduct, in the urine from subjects eating a diet in which the only source of n-3 long-chain, polyunsaturated fatty acids was fresh salmon. Nine healthy men, ages 30-65, were confined in the United States Department of Agriculture Western Human Nutrition Research Center, San Francisco, CA, for 100 d; food intake and exercise levels were controlled. All subjects were placed on a stabilization diet (StD) for 20 d, then six were fed the salmon diet for 40 d. The others remained on the StD. The groups switched diets for the last 40 d. Both diets were isocaloric (16% protein, 54% CHO and 30% fat by energy %). The salmon diet contained 7.5% of calories from n-6 fatty acids (FAs) and 2% from n-3 FAs, primarily eicosapentaenoic acid and docosahexaenoic acid in a 50:60 ratio, while the StD contained 7.5% from n-6 FAs and < 0.3% n-3 FAs (with presumably no significant amounts of C20 or C22 n-3 FAs). Twenty-four hour urinary output was collected, and 2% 3-d pool samples prepared for analysis of urinary TBARS and the TBA-MDA adduct. The total urinary output of each individual varied considerably, and on a daily basis the concentration of autoxidation products in an individual's urine varied also.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1982

Convulsant, anticonvulsant and anaesthetic barbiturates. In vivo activities of oxo- and thiobarbiturates related to pentobarbitone.

The convulsant, anticonvulsant and anaesthetic activities of a series of 6 barbiturates related to pentobarbitone have been qualitatively and quantitatively determined in mice. The presence or absence of convulsant activity was strongly dependent on molecular structure and there were marked variations in potency among the convulsant barbiturates. Anticonvulsant and anaesthetic activities were less dependent on structure and even the convulsant barbiturates had some underlying anticonvulsant action. Qualitative activities are also reported for a series of 8 thiobarbiturates. Convulsant activities were reduced in the thiobarbiturates, but some excitant activity remained in the thio analogue of each convulsant oxobarbiturate.

Anesthetics↗
PubMed1989

Induction of profound hypouricemia by a non-sedating thiobarbiturate.

5-[N-phenylcarboxamido]-2-thiobarbituric acid (merbarone) is a non-sedating derivative of thiobarbituric acid originally developed for anticancer use. In the initial clinical study, a profound reduction in serum uric acid was observed. In 20 patients who received five daily doses of merbarone ranging from 100 to 750 mg/m2, serum uric acid concentration was reduced from a mean pretreatment value of 5.7 +/- 1.6 mg/dL to a mean lowest value of 1.3 +/- 0.5 mg/dL. In most patients, the onset of the effect occurred with 24 hours and was maximal by 48 to 72 hours. Metabolic studies in two patients showed an increase in urinary uric acid excretion within 24 hours after initiation of drug treatment. A marked increase in fractional excretion of uric acid was sustained throughout the period of drug treatment. Urinary excretion of total oxypurines (xanthine and hypoxanthine) was increased twofold to threefold relative to baseline levels. Ultrafiltration studies showed that merbarone did not significantly displace binding of urate from albumin. When merbarone was incubated with xanthine oxidase in vitro, several reaction products were observed, including 2-oxo-2-desthio-merbarone and a compound with retention time similar to 4'-OH-merbarone. Both of these compounds have been described previously as metabolites of merbarone in human subjects. The parent drug and both metabolites were found to inhibit xanthine oxidase (Ki = 41, 36, and 240 mumols/L, respectively). However, this inhibitory effect was substantially less potent than allopurinol (Ki = 0.025 mumols/L). This study indicates that merbarone induces profound hypouricemia primarily by increasing uric acid excretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Antineoplastic Agents↗
PubMed1986

Application of the thiobarbiturate assay to the measurement of lipid peroxidation products in microsomes.

By applying two different thiobarbiturate assay procedures in parallel to aliquots of a microsomal incubation mixture one can simultaneously monitor free malondialdehyde and malondialdehyde plus labile lipid peroxidation products. The levels of malondialdehyde increase continuously during the incubation of microsomes, NADPH and ferrous-ADP complex, while the lipid precursors of MDA stop forming when the system becomes depleted in NADPH. In contrast to systems in which lipids are undergoing autooxidation, NADPH-dependent lipid peroxidation does not appear to generate significant amounts of water-soluble malondialdehyde precursors. As a result, quantitative interpretation of results is straightforward in the microsomal system. In spite of the lack of specificity of the thiobarbiturate coupling reaction, interferences can be easily compensated for by using zero time controls.

Animals↗
PubMed1994

Susceptibility of myelin glycerophospholipids and sphingolipids to oxidative attack by hydroxyl free radicals as measured by the thiobarbituric acid test.

Glycerophospholipids and sphingolipids typical of the myelin sheath have been examined for the formation of thiobarbituric acid reactive materials after attack by hydroxyl free radicals. Thiobarbituric acid (TBA) reactive materials are formed following exposure of phosphatidylcholine (PC), phosphatidylserine (PS) and phosphatidylethanolamine (PE) to hydroxyl radical attack in the order PS > PC > PE while the sphingolipids, sphingomyelin and cerebroside and the sterol cholesterol, did not form TBA reactive materials. Inclusion of cholesterol into PC vesicles reduced the formation of TBA reactive materials on hydroxyl radical attack while with PS there was an increase. In mixed glycerophospholipid systems inclusion of cerebroside reduced formation of TBA reactive materials following hydroxyl radical attack on phosphatidylcholine and phosphatidylserine, but not phosphatidylethanolamine. The findings are discussed in relation to the oxidative damage we have observed in the central nervous system at different stages of chronic relapsing experimental allergic encephalomyelitis [Brett R. and Rumsby M. G. Neurochem. Int. 23, 35-44 (1993)].

Animals↗