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PubMed1979

Mutual antagonism of behavioral effects of TRH and thiobarbiturate on an operant task in rhesus monkeys.

Similar excitatory or depressant response rate dependent effects on monkeys responding on a variable interval reinforcement schedule were observed following intravenous administration of either thyrotropin releasing hormone (TRH) or thiobarbiturate. However, these agents were mutally antagonistic when given together even though the response rate altering effects of each agent were in the same direction. These findings establish an additional behavioral effect of exogenously administered TRH in primates and suggest that barbiturates might alter behavior in part through an interaction with brain TRH receptive mechanisms.

Animals↗
PubMed1994

Thiobarbiturate and fructosamine assays: significance and interest of the borohydride blank.

The acute-phase reaction (APR) induces the production by the liver of short-lived glycoproteins. The carbohydrate moiety of these proteins is thought to interfere with the thiobarbiturate (TBA) and nitroblue tetrazolium colorimetric tests which are used for assaying non-enzymatic glycosylation (NEG) of serum proteins. The aim of the present study was to assess the effect of the APR on the specificity of the colorimetric tests in non-diabetic and diabetic subjects. A positive correlation was found between C-reactive protein (CRP), an APR glycoprotein, and non-specific TBA reactivity as determined after borohydride reduction (BH4-resistant TBA, BR-TBA), both in non-diabetics (r = 0.61; P < 0.01) and diabetics (r = 0.68; P < 0.01). The BH4-sensitive specific TBA (SP-TBA) was not influenced by glycoproteins, and its increase in diabetics was correlated with the nitroblue tetrazolium assay (r = 0.89; P < 0.01). An independent effect of diabetes and APR on non-specific TBA was also demonstrated, suggesting an effect of hyperglycaemia on both protein glycation and glycosylation. TBA with borohydride reduction is an attractive tool for the study of complex glycoproteins in diabetes.

Acute-Phase Reaction↗
PubMed1989

Nephrotoxicity of 5-(N-phenylcarboxamido)-2-thiobarbituric acid in the Fischer 344 rat.

In the present investigation, administration of a single i.p. dose of the anticancer drug merbarone [5-(N-phenylcarboxamido)-2-thiobarbituric acid] produced an acute and reversible decrease in renal function in female but not male Fischer 344 rats. The renal lesion in female rats was biochemically characterized as a decrease in p-aminohippuric acid accumulation by renal slices along with polyuria, glucosuria, proteinuria, and enzymuria. These functional changes were accompanied by histopathologic changes of focal tubular necrosis that was confined to the deep cortex and outer stripe of the outer medulla. The changes in these parameters were dose-dependent and were observed at doses as low as 0.2 x MELD(10) (12 mg/kg). This low merbarone dose increased urinary glucose and protein excretion by 26- and 9-fold, respectively, in the initial 16-h urine collection in female rats. This increase was accompanied by a 2- to 15-fold increase in the excretion of N-acetyl-beta-D-glucosaminidase (NAG), gamma-glutamyl transpeptidase (gamma-GTP), and lactate dehydrogenase (LDH) activities. No significant changes in renal function were observed in male rats apart from mild enzymuria after a high dose of merbarone (36 mg/kg). The drug did not increase urea nitrogen levels in male or female rats, reflecting the focal nature of this tubular lesion. Merbarone produced small elevations in serum transaminase activities [i.e., glutamic-oxalacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT)] at doses that produced marked alterations in renal function in female rats, suggesting only mild hepatotoxicity. The present study establishes the kidney as a possible dose-limiting target organ for merbarone toxicity.

Alanine Transaminase↗
PubMed1989

Early developmental exposure to benzodiazepine ligands alters brain levels of thiobarbituric acid-reactive products in young adult rats.

Levels of thiobarbituric acid (TBA)-reactive material were measured in brain regions of 3-4 month-old rats following prenatal exposure to several benzodiazepine (BDZ) receptor ligands over gestational days 14-20. Prenatal exposure to diazepam (DZ) at 1.0 mg/kg/day markedly elevated levels of brain TBA-reactive material while exposure to a higher dose (2.5 mg/kg) induced a significant increase only in the hippocampus. Early exposure to the central-type BDZ agonist clonazepam as well as to the central-type antagonist Ro 15-1788 also increased brain levels of TBA-reactive material. Concurrent exposure to the higher dose of DZ partially attenuated the effect of Ro 15-1788. Prenatal exposure to the peripheral-type BDZ ligand PK11195 produced a profound increase in TBA-reactive products in all regions, and concurrent DZ exposure did not attenuate this effect, except in the basal ganglia. Measurement of TBA-reactive material from birth to 3 months indicated that the effect of prenatal exposure to DZ was not apparent until after 8 weeks of age. Acute in vitro exposure of adult and fetal tissue to DZ had no effect on TBA-reactive material. The results suggest an interference in the organization of cellular metabolism in the brain by developmental exposure to BDZ ligands.

Animals↗
PubMed1993

Age-related increases in superoxide dismutase activity and thiobarbituric acid-reactive substances: effect of bio-catalyzer in aged rat brain.

This study describes, using electron spin resonance spectrometry/spin trapping technique, the increase superoxide dismutase (SOD) activity in the mitochondrial and cytosolic fraction of the cortex, midbrain, pons-medulla oblongata and cerebellum, and in thiobarbituric acid-reactive substances (TBARS) in the cortex, cerebellum and hippocampus of the aged rats. The results show that corresponding to the increased life span and improved physical conditions observed after peroral long-term treatment with Bio-catalyzer, a commercial natural fermented health food supplement marketed in Japan and in the Philippines and earlier reported to be a hydroxyl radical scavenger with weaker scavenging activity on superoxide radical (O-2), SOD which is involved in the metabolic degradation of O-2 was further increased, whereas TBARS decreased. These findings suggest that the increased SOD activity in the brain as a defense mechanism against age-related accumulation of reactive oxygen species, in particular superoxide radicals, was enhanced with Bio-catalyzer treatment while age-related peroxidation of neuronal membrane, as measured by TBARS, was decreased.

Aging↗
PubMed1986

[Concentration of thiobarbituric acid reactive substances (TBARS) in serum following myocardial infarct].

The serum concentration of thiobarbituric acid reactive substances (TBARS), which can be used in the characterization of O2-radical metabolism, was analyzed in patients with myocardial infarction in the acute phase, 10-14 days, 1 month, and 6 months after infarction, and compared with the TBARS concentration of a healthy group and a group with atherosclerosis. After myocardial infarction we found increased TBARS concentration at all moments of investigation in comparison with the healthy and atherosclerosis groups. Maximum concentration was found 10-14 days after infarction, afterwards the TBARS concentration decreased, without however attaining the values which we found in the comparison groups. The increased TBARS concentration 6 months after myocardial infarction demonstrates a manifestation of disturbances in the O2-radical metabolism. Such disturbances may be regarded as a high-risk factor to the cardiovascular system.

Arteriosclerosis↗
PubMed1986

Reaction of thiobarbituric acid with saturated aldehydes.

The reaction of thiobarbituric acid (TBA) with saturated aldehydes, i.e., 1-butanal, 1-hexanal and 1-heptanal, produced a 455-nm yellow and a 532-nm red pigment. Formation of the pigments depended on the reaction conditions. The yellow pigment was unstable in the presence of excess amounts of the saturated aldehydes. The red pigment was formed only when the reaction was performed at a TBA/aldehyde ratio of 1:1 in aqueous acetic acid. Formation of the yellow and red pigments required molecular oxygen. The colorless adducts, intermediates for the yellow and the red pigments, were isolated from the reaction mixtures. Aldol condensation and dehydration of 2 mol of the saturated aldehydes initially gave the alpha, beta-unsaturated aldehydes, which in turn reacted with TBA to form the colorless adducts, pyranopyrimidine derivatives. The adducts were then converted into the yellow and red pigments under aerobic conditions.

Aldehydes↗
PubMed1988

Analysis of cardiac membrane phospholipid peroxidation kinetics as malondialdehyde: nonspecificity of thiobarbituric acid-reactivity.

When exposed to xanthine oxidase (superoxide)-dependent, iron-promoted Fenton chemistry, purified cardiac membranes evidenced, by the thiobarbituric acid (TBA) test, a virtually instantaneous peroxidative response with a maximal linear rate of 5.8 nmol malondialdehyde (MDA)-equivalents/mEquivalents lipid ester reacted/min. Yet when the lipids purified from these same membranes and reconstituted into liposomes were peroxidized under identical reaction conditions, the TBA test indicated that a pronounced (approximately 20-min) lag period preceded a maximal peroxidation rate of only 2.1 nmol MDA-equivalents/mEquivalents lipid ester reacted/min. After 120 min of peroxidation, the cardiac membranes yielded some 300 nmol TBA-reactive MDA-equivalents/mEquivalent ester, whereas the isolated membrane lipids evidenced approximately 40% less TBA-reactivity. To verify that these quantitative and kinetic differences in membrane (phospho)-lipid peroxidation occurred with removal of the lipids from their membrane milieu, the MDA produced during both cardiac membrane peroxidation and the peroxidation of the lipids derived therefrom was isolated as its free anion by ion-pair high-pressure liquid chromatography. As quantified spectrophotometrically, true MDA production during myocardial membrane peroxidation was identical in kinetics and in amount to the production of TBA-reactive substance from the peroxidized isolated membrane lipids. These results demonstrate that significant non-MDA, TBA-reactive species are generated during the peroxidation of cardiac membranes, especially before the maximal rates of bona fide MDA production. As a direct consequence, artifactual levels and kinetics of membrane lipid peroxidation do result.

Animals↗
PubMed1992

Levels of thiobarbituric acid reactive substances and the cytocidal potential of gammalinolenic and docosahexaenoic acids on ZR-75-1 and CV-1 cells.

To clarify the mechanism by which gammalinolenic acid (GLA) is more tumoricidal than docosahexaenoic acid (DHA), we have compared the incorporation of the respective exogenously added ethyl esters GLAe and DHAe into the phospholipids of tumorigenic ZR-75-1 and non-tumorigenic CV-1 cells relative to the ability of the cells to survive and to accumulate thiobarbituric acid reactive substances (TBARS). GLA and DHA were incorporated in the phospholipids to the same extent, but GLA disappeared more rapidly than DHA in both cell lines. GLAe induced about twice as much intracellular TBARS as DHAe in both cell lines, but killed ZR-75-1 cells four times more effectively than DHAe. DHAe induced 11-15 fmoles malondialdehyde-equivalents (MDA-eq)/cell in both ZR-75-1 and CV-1 cells, whereas GLAe induced 5-6 times more TBARS in ZR-75-1 cells (26-30 fmoles MDA-eq/cell) than in CV-1 cells (5-6 fmoles MDA-eq/cell). The results show that there is no difference in GLA and DHA incorporation into phospholipids, but that their metabolism differs in the two cell types. The data also suggest that the cytocidal potential is related to TBARS levels in a nonlinear fashion. The relationship between excess prostaglandin production and excessive cell death due to GLA is discussed.

Animals↗
PubMedDate not supplied

Glycated serum protein determination: comparison between thiobarbituric acid and fructosamine assays.

Glycated serum proteins were evaluated with fructosamine (GSP-fructosamine) and thiobarbituric acid (GSP) assays in 60 normal and 60 diabetic subjects. Higher levels of GSP-fructosamine and GSP were found in diabetics in comparison to controls. GSP-fructosamine levels were positively related to GSP values and the other metabolic control parameters. Moreover, the fructosamine assay is sensitive, reproducible, rapid and easy to perform. Thus, fructosamine assay could be a useful method for glycated serum protein evaluation in diabetic patients.

Adult↗
PubMedDate not supplied

Lipid peroxidation assessed by serum thiobarbituric acid reactive substances in healthy subjects and in patients with pathologies known to affect trace element status.

Serum thiobarbituric acid reactive substances (TBARS), Zn, Cu, and Se concentrations were determined in 47 healthy adults and in patients with diseases, such as renal insufficiency, insulin-dependent diabetes mellitus, chronic pancreatitis, liver cirrhosis, or cancer, in order to clarify the relationship between this indicator of lipid peroxidation and antioxidative trace element status. TBARS levels were higher than control values in all pathological cases, except in cancer patients. Cu levels in patients highly correlated with ferroxidase ceruloplasmin activity (r = 0.86), but were only statistically different from controls in diabetics. Zn levels were lower than normal in dialysis, liver cirrhosis, and cancer patients. Se levels were significantly decreased in all pathological cases. Half of the subjects with liver cirrhosis or renal insufficiency and 3/4 of chronic pancreatitis or cancer patients had an active inflammatory process. Despite intense modifications in determined indicators, no clear correlation could be demonstrated between the different parameters. Basic antioxidative trace element status and inflammation are therefore not major determinants of TBARS levels in normal and in pathological conditions, despite of the frequent association of low serum Zn and mainly low serum Se with high TBARS levels.

Adult↗
PubMed2004

Testicular tissue nitric oxide and thiobarbituric acid reactive substance levels: evaluation with respect to the pathogenesis of varicocele.

The aim of the present study is to evaluate tissue nitric oxide (NO) and thiobarbituric acid reactive substance (TBARS) levels in testicular tissue, and to determine their relationship with seminal parameters in order to explain possible effects on varicocele pathophysiology. Ten adult male Wistar rats at 8 weeks old underwent partial left renal vein ligation. A sham operation was performed on control rats in a second group of another ten rats. All animals were killed 4 weeks after surgery. The testes were removed and histological changes were observed by light microscopy with haematoxylin and eosin stain on half of each testis. The rest of testis was used for the evaluation of testicular tissue NO and TBARS levels. Epididymal aspirated seminal plasma was used for semen analysis and morphological analysis was carried out according to Kruger's criteria. Statistical analysis was performed by using Mann-Whitney U-tests and Spearman rank correlations between the two groups for NO and TBARS levels and for seminal parameters. Testicular tissue NO and TBARS levels (mean+/-SEM) were 62.8+/-10.1 micromol/g protein and 4.7+/-0.3 nmol/g protein in group 1. These parameters were 16.9+/-2.2 micromol/g protein and 3.1+/-0.2 nmol/g protein in the group 2 controls. There were significant differences between these parameters ( P(NO)=0.000, P(TBARS)=0.001). Although a positive and significant correlation between testicular tissue NO and TBARS levels was found ( r(s)=0.739, P=0.014), there was only a strong negative correlation between NO levels and sperm motility in group 1 ( r(s)=-0.815, P=0.004). We found that this effect of NO on sperm motility was independent from TBARS levels after regression analysis ( r(2)=-0.687, beta=0.825, P=0.034). Although there were statistically significant differences in seminal parameters between the two groups, there was no difference between them in the histopathological examination. We found that sperm motility was significantly related to testicular tissue NO levels only. Thus, we suggest that NO is an important mediator in the pathogenesis of varicocele. TBARS and other substances have been effective via NO pathways.

Animals↗
PubMed2005

Catalase activity and thiobarbituric acid reactive substances (TBARS) production in a rat model of diffuse axonal injury. Effect of gadolinium and amiloride.

This study evaluated the effect of mechanogated membrane ion channel blockers on brain catalase (CAT) activity and thiobarbituric acid reactive substances (TBARS) production after traumatic brain injury (TBI). A weight drop trauma model was used. Controls were sham-operated and received no weight drop. Gadolinium (GAD) or amiloride (AMI) were administered to control and experimental rats (30 min after TBI). Brain CAT activity and TBARS production were measured. When blood vessels were washed out with saline perfusion brain CAT activity significantly increased up to 6 h after trauma, decreasing significantly by 24 h; GAD or AMI administration preserved CAT activity 24 h after TBI. TBARS production increased after trauma, this effect being significantly reversed by GAD or AMI administration. GAD significantly decreased TBARS production in control animals. Mechanogated membrane ion channels may be involved in the genesis of the ionic disruption leading to oxidative stress and other secondary injury processes in head trauma.

Amiloride↗
PubMed1978

The characterisation of thiobarbituric acid reactivity in human plasma and urine.

The specificity of the thiobarbituric acid reaction (TBA) has been investigated using techniques of high-performance thin-layer chromatography and spectrofluorimetry. It was found that malondialdehyde (MDA) derived from different lipid and nonlipid origins formed the same MDA-TBA complex. This complex could be separated from other TBA-reactive compounds by both chromatography and spectrofluorimetry. Normal human plasma and urine both formed an MDA-TBA complex along with other TBA-reactive compounds. In plasma this was associated mainly with phosphatidylcholine and appeared to be peroxidic in reaction. Urine, however, contained polar MDA-forming compounds probably resulting from the oxidation of 2-deoxyaldoses during the acid-heating stage of the TBA test.

Chromatography, Thin Layer↗
PubMed1984

A method to reduce interference by sucrose in the detection of thiobarbituric acid-reactive substances.

A thiobarbituric acid (TBA) reaction for measuring lipid peroxidation products was evaluated for interference by several ingredients commonly used in solutions to prepare or analyze tissue homogenates or subcellular organelles. These included sucrose (up to 100 mM final concentration in the assay medium), Tris-maleate (up to 40 mM), imidazole (up to 20 mM), inorganic phosphate (up to 10 mM), and 4- morpholinepropanesulfonic acid (up to 20 mM). When the samples were heated at 95 degrees C as recommended in some procedures, only sucrose significantly affected color development. Sucrose concentrations as low as 10 mM significantly increased absorbance at 532 nm of aqueous tetramethoxypropane (TMP) standards, and so the assay could not be applied reliably to tissue samples prepared in sucrose. Sucrose interference was only partially reduced by subsequent organic extraction (n-butanol plus pyridine), with measured absorbances remaining significantly greater (50-100%) than sucrose-free controls at sucrose concentrations of 20 mM or more. Modifying the assay to include sucrose in blanks and TMP standards failed to adequately correct for interference when the absorbance of unextracted (aqueous) solutions was measured. Further modification by adding sucrose to blanks and TMP standards, followed by butanol-pyridine extraction, gave standard curves that were linear, through the origin, and had slopes equivalent to those of sucrose-free standards. This modification enabled almost complete recovery (average 2% error) of known amounts of TMP added to aliquots of tissue homogenates containing amounts of sucrose that otherwise significantly interfered. Also, with the modified method the content of TBA-reactive substances in tissues homogenized in sucrose was found to be not significantly different from that measured in tissues homogenized in a noninterfering substance, KCl.

Animals↗
PubMed1986

High-performance liquid chromatography analysis of the thiobarbituric acid adducts of malonaldehyde and trans,trans-muconaldehyde.

A reversed-phase HPLC method is described for the separation and analysis of the thiobarbituric acid (TBA) adducts of the reactive aldehydes muconaldehyde (MUC) and malonaldehyde (MDA). The TBA adduct of malonaldehyde was synthesized, purified, and its structure elucidated, for use as standard in quantitative HPLC studies. A detection limit of 1 X 10(-14) mol was achieved for the MUC:TBA and MDA:TBA adducts using the double monochromator fluorometric detector, 7 X 10(-13) mol was the detection limit using a variable wavelength uv-visible detector. Direct on-line identification of the eluting aldehyde:TBA adducts was achieved by the use of a diode-array uv-visible detector. The chromatographic behavior of the adducts under different mobile phase conditions was also examined. This HPLC methodology was used for the identification of muconaldehyde as a product of benzene oxidation in a hydroxyl radical generating system.

Aldehydes↗
PubMed1987

Formation of yellow, orange, and red pigments in the reaction of alk-2-enals with 2-thiobarbituric acid.

The reaction of four to eight carbon straight-chain alk-2-enals with 2-thiobarbituric acid (TBA) produced yellow 455-nm-, orange 495-nm-, and red 532-nm-absorbing pigments depending upon the reaction conditions. The 1:1 reaction of the aldehydes with TBA in 15% acetic acid at 100 degrees C produced the yellow pigment at 0.25 h and the red at 6 h. The reaction of the aldehydes with TBA in excess at 100 degrees C produced the yellow at 0.25 h, the orange at 2-6 h, and the red at 0.25-6 h. The formation of these pigments required molecular oxygen. These pigments could be separated from each other on HPLC. The red pigment formed from the aldehydes could not be distinguished from the red 1:2 malonaldehyde-TBA adduct by absorption spectrum and HPLC. The red color yield was the highest in the 1:1 reaction and retarded in the reaction with TBA in excess. The red color due to these aldehydes may contribute in part to the color formed in the general TBA test of lipid oxidation. The 1:1 reaction initially produced colorless 1:1 adducts X, which were subsequently converted into the yellow and red pigments under aerobic conditions. The reaction of the aldehydes with TBA in excess might initially produce X and then another colorless 1:2 adducts Y; the latter being converted into yellow, orange, and red pigments under aerobic conditions.

Aldehydes↗
PubMed1989

Determination of thiobarbituric acid-reactive substances in oxidized lipids by high-performance liquid chromatography with a postcolumn reaction system.

A new high-performance liquid chromatography procedure with a postcolumn reaction system for determination of free malondialdehyde (MDA) and other thiobarbituric acid-reactive substances (TBA-RS) in oxidized lipids in vitro has been developed. Using this procedure, both thermally oxidized methyl linoleate and the degradation products of methyl linoleate hydroperoxides revealed many kinds of lipophilic TBA-RS, but no free MDA was detected on the high-performance liquid chromatography. Similarly, oxidized methyl arachidonate also produced certain kinds of TBA-RS in the lipophilic phase and a small amount of free MDA in the hydrophilic phase. These results indicate that lipophilic TBA-RS produced in oxidized lipids in vitro are major TBA-RS and that the production of free MDA is small, even though the degree of lipid oxidation has previously been estimated as an MDA equivalent measured by the TBA colorimetric test.

Animals↗