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PubMedDate not supplied

[Effect of heavy mechanical trauma on content of lactic and pyruvic acids in rat brain].

The content of lactic and pyruvic acids in the brain was studied as affected by heavy mechanical trauma. It was established that under the trauma effect the content of lactic acid in the brain tissue increases and phase changes are observed in the content of pyruvic acid and in the value of the lactate pyruvate ratio. Lactic acid accumulates most intensively in the cerebellum, cortex and subcortical areas of the brain, and less intensively--in medulla oblongata and spinal cord.

Animals↗
PubMed1985

Synthesis, formulation, and clinical pharmacological evaluation of hydralazine pyruvic acid hydrazone in two healthy volunteers.

Hydralazine pyruvic acid hydrazone [2-(phthalazin-1-yl hydrazono)propionic acid; 1] is a major plasma metabolite of hydralazine in humans. A number of in vitro and animal studies have suggested that this hydrazone may have cardiovascular activity and could account for the prolonged antihypertensive effect of hydralazine in humans in the absence of detectable plasma levels of the parent drug. To study this possibility, the soluble sodium salt of hydralazine pyruvic acid hydrazone (2) was synthesized, its chemical purity and stability was checked, and an intravenous formulation was prepared. Isomeric forms were identified. Doses of 0.3, 0.6, and 1.1 mumol/kg of 2 were administered intravenously to one slow and one heterozygous fast acetylator of sulfamethazine. The slow acetylator received two additional doses of 0.06 and 0.14 mumol/kg. Peak plasma levels of 1 of 18 mumol/L were attained without tachycardia or hypotension in either subject. There was no evidence of nonlinearity in kinetics over the dose range studied and clearance remained constant in both subjects (0.517 +/- 0.033 mL/min/kg in the slow acetylator and 0.744 +/- 0.058 mL/min/kg in the fast acetylator). The distribution of 1 varied unpredictably with dose, and changes were reflected in the terminal half-life (3.47-5.97 h in the slow acetylator and 2.06-5.33 h in the fast acetylator). Only traces of the acetylated metabolite of hydralazine, 3-methyl-s-triazolo[3,4-a]phthalazine (3), were detected in the plasma of the subjects, suggesting that significant metabolism via this route was unlikely. An established and specific assay for hydralazine was further modified to allow measurement of levels as low as 1 nmol/L (0.2 ng/mL).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylation↗
PubMed1978

[Changes in the mitotic activity of corneal epithelial cells under the influence of pyruvic acid].

92 specimens of rat's corneal epithelium were studied to estimate the effect of pyruvic acid on cell division characteristics. 0.1 M solution of pyruvic acid decreases the mitotic activity of rat corneal epithelium, the portion of prophase increasing the number of metaphase decreasing. These results support a hypothesis on the possible role of low molecular acceptors in the cell division regulation "in vivo", and suggests the effect of pyruvic acid both during the period prior to cell division, and the prophase-metaphase stage.

Animals↗
PubMed1992

The primary structure of omega-amino acid:pyruvate aminotransferase.

The complete amino acid sequence of bacterial omega-amino acid:pyruvate aminotransferase (omega-APT) was determined from its primary structure. The enzyme protein was fragmented by CNBr cleavage, trypsin, and Staphylococcus aureus V8 digestions. The peptides were purified and sequenced by Edman degradation. omega-ATP is composed of four identical subunits of 449 amino acids each. The calculated molecular weight of the enzyme subunit is 48,738 and that of the enzyme tetramer is 194,952. No disulfide bonds or bound sugar molecules were found in the enzyme structure, although 6 cysteine residues were determined per enzyme subunit. Sequence homologies were found between an omega-aminotransferase, i.e. mammalian and yeast ornithine delta-aminotransferases, fungal gamma-aminobutyrate aminotransferase and 7,8-diaminoperalgonate aminotransferase, and 2,2-dialkylglycine decarboxylase. The enzyme structure is not homologous to those of aspartate aminotransferases (AspATs) including the enzymes of Escherichia coli and Sufolobus salfactaricus, though significant homology in the three-dimensional structures around the cofactor binding site has been found between omega-APT and AspATs (Watanabe, N., Sakabe, K., Sakabe, N., Higashi, T., Sasaki, K., Aibara, S., Morita, Y., Yonaha, K., Toyama, S., and Fukutani, H. (1989) J. Biochem. 105, 1-3).

Amino Acid Sequence↗
PubMed1992

High-performance liquid chromatography-fluorescence assay of pyruvic acid to determine cysteine conjugate beta-lyase activity: application to S-1,2-dichlorovinyl-L-cysteine and S-2-benzothiazolyl-L-cysteine.

An HPLC-fluorescence assay has been developed for the determination of the activity of rat renal cytosolic cysteine conjugate beta-lyase. The method is based on isocratic HPLC separation and fluorescence detection of pyruvic acid, derivatized with o-phenylenediamine (OPD), and is shown to be rapid, specific, and very sensitive. The assay has been evaluated with two model substrates for rat renal cytosolic beta-lyase, notably S-1,2-dichorovinyl-L-cysteine (DCVC) and S-2-benzothiazolyl-L-cysteine (BTC). Equimolar formation of pyruvic acid and 2-mercaptobenzothiazole, a chromophoric thiol, indicated that pyruvic acid formation actually reflects the beta-elimination activity of beta-lyase during the beta-elimination of BTC. From this it follows that the pyruvic acid assay can be applied to the measurement of the beta-elimination activity of this enzyme, independent of the presence of chromophoric groups or radiolabels in substrates. Due to the large linear range and the very high sensitivity of the present HPLC-fluorescence assay (detection limit, 7.5 pmol of pyruvic acid), both good and poor substrates of beta-lyase can be measured. Enzyme kinetic data are presented for the model substrates BTC and DCVC and for four structurally related S-2,2-difluoroethyl-L-cysteine conjugates.

Animals↗
PubMed1986

Effects of pyruvate salts, pyruvic acid, and bicarbonate salts in preventing experimental oxalate urolithiasis in rats.

Sodium pyruvate, potassium pyruvate, pyruvic acid, sodium bicarbonate and potassium bicarbonate were added to a calcium-oxalate lithogenic diet (a glycolic-acid diet) in order to determine their effects in preventing lithogenicity. Male Wistar-strain rats who had been fed the glycolic-acid diet developed marked urinary calculi within four weeks. Rats in the sodium and potassium pyruvate groups had, however, almost no stones in the urinary system. Rats in the bicarbonate and pyruvic-acid groups showed slightly less effect than those in the pyruvate groups. Urinary oxalate excretion was high in all the groups during the experiment. The urinary oxalate concentration was relatively higher in the sodium-pyruvate group, and significantly higher in the potassium-pyruvate group, than in the glycolic-acid group. Urinary citrate excretion was high both in the pyruvate and bicarbonate groups; the urinary citrate concentration was, however, significantly higher in the pyruvate groups than in the bicarbonate groups at the fourth experimental week. The urinary calcium and magnesium concentrations were irrelevant to the diets administered. Therefore, it can be concluded that pyruvate salts inhibit urinary calculi formation, not by decreasing oxalate synthesis, but by increasing the urinary citrate concentration; bicarbonate salts work in the same manner, but a little less effectively.

Animals↗
PubMed1976

Sexual difference in pituitary pyruvic acid content, as well as of lactic acid/pyruvic acid quotient.

The lactic acid/pyruvic acid quotient of rat anterior pituitary varies betweeen 30 and 80. The dominance of lactic acid is in accordance with the earlier observation that pituitary lactate dehydrogenase isoenzymes in rat are made up, in majority, of M subunits. The pituitary lactic acid concentration in female and male animals shows no appreciable difference and does not change 2 and 4 weeks after castration. In males the pituitary pyruvic acid concentration was almost double of that in females. Pyruvic acid content increases after ovariectomy and decreases after orchidectomy. The sexual differences having been observed in lactic acid/pyruvic acid quotient are in correlation with the discrepancy of pyruvic acid concentration.

Animals↗
PubMed1977

Pulpal response to pyruvic acid.

Etching of enamel surfaces produces a marked increase in the bond strength of dental materials to tooth structure. The results of recent studies have indicated that pyruvic acid may be used in preference to phosphoric acid, because of its milder etching effect on enamel surfaces, without adversely affecting the bond strength. The pulpal responses elicited by 10% pyruvic acid applied for 90 seconds to freshly prepared cavities in monkey teeth, were examined after 4, 14 and 42 days. The differences between some of the ariteria used to evaluate the pulpal responses in acid-treated and control teeth at the three post-operative time intervals were statistically significant. These results suggest that exposed dentin should be protected with a lining before etching adjacent enamel surfaces with 10% pyruvic acid.

Acid Etching, Dental↗
PubMed1991

[Pyruvic acid in the rat liver and myocardium after acute chlorfenvinphos poisoning].

The authors studied the effect of chlorfenvinphos on the pyruvic acid level in the liver and cardiac muscle of male Wistar rats. The animals were intoxicated with chlorfenvinphos in a single oral dose of 5 mg/kg (0.5 LD50). The pyruvate was assayed spectrophotometrically after 2, 4 and 24 hours following administration of the insecticide. The results obtained indicate that after intoxication with chlorfenvinphos there are no changes in the pyruvic acid level in the liver, but in the heart muscle, two hours after administration of insecticide, a significant decrease of this keto acid was observed. No alterations were found 4 and 24 hours after intoxication with chlorfenvinphos.

Acute Disease↗
PubMed1979

Pharmacokinetics of hydralazine, apparent hydralazine and hydralazine pyruvic acid hydrazone in humans.

Hydralazine is an antihypertensive vasodilator agent. Lack of specific assay techniques for its measurement have delayed elucidation of its pharmacokinetic profile. This study compares the plasma profiles of hydralazine, measured both by a specific and by a previously published nonspecific assay and of a major plasma metabolite, hydralazine pyruvic acid hydrazone. After po and iv administration of hydralazine, peak hydralazine levels were lower (7-33%) and plasma half lives were shorter (15-31%) when measured by the specific technique. The mean plasma half life of the pyruvic acid hydrazone was 156 min and mean urinary clearance, 28 ml/min. The plasma profile of hydralazine and of the major metabolite, the pyruvic acid hydrazone, do not appear to correspond to the duration of antihypertensive effect of administered hydralazine.

Acetylation↗
PubMed1979

Pharmacokinetics and cardiovascular effects in rabbits of a major hydralazine metabolite, the hydralazine pyruvic-acid hydrazone.

The hydrazone of hydralazine and pyruvic acid (HPH) has been recognized as a quantitatively important metabolite of hydralazine in human plasma. We evaluated the disposition of [14C] HPH after its i.v. administration to normal, anephric and probenecid-pretreated rabbits. Renal clearance of HPH in normal rabbits exceeded the glomerular filtration rate by a factor of 3 to 4 and accounted for 80 to 90% of the total body clearance. Active tubular secretion was established by the effect of probenecid pretreatment to reduce the renal clearance of HPH by 80%. Total body clearance of HPH in anephric rabbits was 10% of that of normal animals, emphasizing the minor importance of metabolic conversion for the overall disposition of HPH. HPH in a maximum dose of 50 mumol/kg i.v. had no hypotensive effect in renal hypertensive rabbits and did not interfere with the subsequent hypotensive response to hydralazine. This HPH dose produced plasma levels at least 50 times in excess of those reported in humans after administration of therapeutic doses of parent hydralazine. HPH is consequently of negligible clinical significance, despite the relatively high plasma concentration of this metabolite which occurs after administration of parent hydralazine.

Animals↗
PubMed1979

[Occurrence of pyruvic acid in capsular polysaccharides (K antigens) of klebsiellas].

The capsular polysaccharides of 77 Klebsiella K-types were analysed for the presence of pyruvic acid. One half of the polysaccharides investigated were found to contain between 1.3 and 12% of the keto acid. A comparison between the analyses performed and the calculated values from some pyruvic acid containing polysaccharides of known structure showed that there is only in 5 out of 10 cases a good correlation with a regular substitution of the oligosaccharide repeating units.

Cell Wall↗
PubMedDate not supplied

[The effectiveness of some culture media with pyruvic acid bases for the isolation of mycobacteria from sputum].

The authors have studied the value of culture media based on pyruvic acid (the Dixon medium and an original medium called P.T.) in the isolation of mycobacteria from sputum, as compared with the Löwenstein-Jensen medium. The studies were carried out in two groups of patients: 1043 samples were collected from ambulatory patients and 1740 samples were collected from hospitalized patients. The superiority of the Dixon and of the P.T. media was confirmed by the increased percentage of positive cultures (11% and 20% respectively) as compared with the Löwenstein-Jensen medium. With these media it was possible to isolate mycobacteria 7--14 days earlier than with the other media. On the basis of the results obtained the authors recommend the use, in parallel, especially in those cases when the samples contain only a small number of bacteria, of the Löwenstein-Jensen medium and one of the media based on pyruvic acid.

Culture Media↗
PubMed1991

Analysis of a pyruvic acid acetal-containing polysaccharide by the reductive-cleavage method.

The applicability of the reductive-cleavage method to the analysis of polysaccharides bearing pyruvic acid acetals has been demonstrated. Direct reductive cleavage of fully methylated gum xanthan yielded the expected products, including 1,5-anhydro-4,6-O-[(S)-1-methoxycarbonylethylidene]-2,3-di-O-methy l-D- mannitol. The latter product was not observed when reductive cleavage was performed subsequent to reduction of ester groups in the fully methylated polysaccharide and mild hydrolysis to remove pyruvic acid acetal substituents. Instead, the latter experiment yielded 1,5-anhydro-2,3-di-O-methyl-D-mannitol, establishing the presence in the polysaccharide of terminal (nonreducing) D-mannopyranosyl groups bearing 4,6-O-(1-carboxyethylidene) substituents. The products of reductive cleavage were characterized, where appropriate, by comparison of the gas chromatographic retention times and chemical ionization- and electron ionization-mass spectra of their acetates to those of authentic standards. Alternatively, the products of reductive cleavage could be characterized without resort to comparison with authentic standards by analysis of the 1H-n.m.r. spectra of their benzoates, which were obtained in pure form by high-performance liquid chromatography. By either method of product characterization, this two-step procedure of analysis reveals the presence of pyruvic-acetal residues in polysaccharides and establishes both the identity of the sugar residue to which they are attached and their positions of attachment.

Carbohydrate Sequence↗
PubMed1978

Interference in assays for hydralazine in humans by a major plasma metabolite, hydralazine pyruvic acid hydrazone.

The present study showed that published spectrophotometric and GLC methods for hydralazine in plasma do not distinguish between the drug and a major plasma metabolite, hydralazine pyruvic acid hydrazone. These methods involve the acid treatment of the sample, which hydrolyzes that hydrazone back to hydralazine. A specific GLC assay for the hydrazone was developed and involves its selective extraction from plasma and transformation to 3-trifluoromethyl-s-triazolo[3,4-a]phthalazine. This derivative could be sensitively measured by GLC using an electron-capture detector. With this procedure, it was shown that most "apparent hydralazine" in plasma is the hydrazone, which forms rapidly from hydralazine and endogenous pyruvic acid. Previous work indicated that the hydrazone was inactive when administered intravenously to rabbits.

Chromatography, Gas↗