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At least 775 records · Page 43Linked to original sources
PubMed1984

The enhancement of tumor cell susceptibility to macrophage binding and cytolysis by p-aminobenzoic acid-N-xyloside sodium salt (K-247).

The enhancement of tumor cell susceptibility to macrophage binding and cytolysis by the pretreatment of tumor cells by p-aminobenzoic acid-N-xyloside sodium salt (K-247) was investigated in the C3H/He mouse-syngeneic tumor system. Binding and cytolytic activities of Corynebacterium parvum-activated macrophages were significantly enhanced when target MM-102 and MH-134 cells were pretreated with K-247 at doses of 200 or 400 micrograms/ml, while thioglycollate-elicited macrophages showed much lower binding and lytic activities against K-247 pretreated target cells. No enhancement of these activities were observed when target cells were pretreated with D-xylose, which had no anti-tumor activity. Furthermore, in a binding assay a significant reduction of macrophage binding to target cells by the K-247 pretreated cold competitors was observed. It is suggested that target cell susceptibility to macrophage cytolytic activity might be enhanced by pretreatment with K-247, involving an initially increased target binding.

4-Aminobenzoic Acid↗
PubMed1987

Inhibition of metabolic processes by coenzyme-A-sequestering aromatic acids. Prevention by para-chloro- and para-nitrobenzoic acids.

Octanoate, salicylate, valproic acid, p-octyl-, p-nitro-, and p-chlorobenzoic acids were effective inhibitors of benzoic acid activation to benzoyl-CoA by mitochondrial extracts. p-Aminobenzoic acid was much less effective. Of these compounds, only salicylate and p-nitrobenzoic acid were not activated to their respective CoA esters. Salicylate, p-chloro- and p-nitrobenzoic acids effectively prevented inhibition of glucose synthesis and alpha-keto[1-14C]isovalerate oxidation by valproic acid, p-octyl-, and p-aminobenzoic acids, p-Octyl- and p-aminobenzoic acids greatly depleted hepatocyte free CoA and acetyl-CoA contents and increased the content of acid-insoluble and acid-soluble CoA esters respectively. p-Chloro- and p-nitrobenzoic acids prevented the sequestration of CoA as p-octylbenzoyl-CoA or p-aminobenzoyl-CoA in hepatocytes incubated with these compounds. p-Chlorobenzoic acid not only prevented but also reversed the inhibition of gluconeogenesis in hepatocytes incubated with p-octylbenzoic acid. These results suggest that p-chloro- or p-nitrobenzoic acids might be effectively used to reverse some of the hepatotoxic effects of the CoA esters of valproic acid or naturally-occurring organic acids, such as those which accumulate in Reye's Syndrome or organic acidemias.

4-Aminobenzoic Acid↗
PubMed1982

[Antitumor effects of p-aminobenzoic acid-N-xyloside Na--effects of single administration and combination with radiotherapy].

Therapeutic effect of p-aminobenzoic acid-N-xyloside Na (K-247) were studied. Eleven patients with a variety of solid tumors were treated with K-247 alone. K-247 was given orally 800mg daily for 4 weeks. As for side effect of the drug, only mild gastritis was observed in a few patients. Partial response (over 25% reduction of tumor size) with a median duration of two months was observed in 3 patients. These cases were metastatic tumor of lung from the carcinoma of thyroid, metastatic tumors of lung from the carcinoma of kidney, and mediastinal tumor. In eight patients the response was classified as no change and in one patient there was progressive disease. Thus K-247 has some therapeutic activity in patients with solid tumor. Combination therapy of irradiation and administration of K-247 were also studied. In twelve patients received the combination therapy, partial response was observed in 7 patients with complete response in 3 patients. In some patients it seems that the effect of irradiation was enhanced by K-247 administration. To confirm this observation, randomized controlled trial is required.

4-Aminobenzoic Acid↗
PubMed2002

Ortho-aminobenzoic acid-labeled bradykinins in interaction with lipid vesicles: fluorescence study.

The peptide hormone bradykinin (BK) (Arg(1)-Pro(2)-Pro(3)-Gly(4)-Phe(5)-Ser(6)-Pro(7)-Phe(8)-Arg(9)) and its shorter homolog BK(1-5) (Arg(1)-Pro(2)-Pro(3)-Gly(4)-Phe(5)) were labeled with the extrinsic fluorescent probe ortho-aminobenzoic acid (Abz) bound to the N-terminal and amidated in the C-terminal carboxyl group (Abz-BK-NH(2) and Abz-BK(1-5)-NH(2)). The fragment des-Arg(9)-BK was synthesized with the Abz fluorescent probe attached to the 3-amino group of 2,3-amino propionic acid (DAP), which positioned the Abz group at the C-terminal side of BK sequence, constituting the peptide des-Arg(9)-BK-DAP(Abz)-NH(2). The spectral characteristics of the probe were similar in the three peptides, and their fluorescent properties were monitored to study the interaction of the peptides with anionic vesicles of dimyristoylphosphatidylglycerol (DMPG). Time-resolved fluorescence experiments showed that the fluorescence decay of the peptides was best described by double-exponential kinetics, with mean lifetimes values around 8.0 ns in buffer pH 7.4 that increased about 10% in the presence of DMPG vesicles. About a 10-fold increase, compared with the values in aqueous solution, was observed in the steady-state anisotropy in the presence of vesicles. A similar increase was also observed for the rotational correlation times obtained from time-resolved anisotropy decay profiles, and related to the overall tumbling of the peptides. Equilibrium binding constants for the peptide-lipid interaction were examined monitoring anisotropy values in titration experiments and the electrostatic effects were evaluated through Gouy-Chapman potential calculations. Without corrections for electrostatic effects, the labeled fragment Abz-BK(1-5)-NH(2) presented the major affinity for DMPG vesicles. Corrections for the changes in peptide concentration due to electrostatic interactions suggested higher affinity of the BK fragments to the hydrophobic phase of the bilayer.

Bradykinin↗
PubMed1996

Mechanism for synergism between sulphonamides and trimethoprim clarified.

Pseudomonas aeruginosa, Escherichia coli, Pseudomonas cepacia and Moraxella catarrhalis were selected for their markedly different resistance patterns to sulphonamides and trimethoprim. In addition, strains of E. coli and P. cepacia were selected having different resistance profiles to the inhibition of dihydropteroate synthetase and dihydrofolate reductase. All inhibitors of dihydropteroate synthetase combined in any combination with inhibitors of dihydrofolate reductase resulted in mutual enhancement of bacterial uptakes of the inhibitors and corresponding increased antibacterial activity of the combinations. High concentrations of sulphonamides or p-aminobenzoic acid plus trimethoprim caused a decrease in overall activity of the combination and indicated that both sulphonamides and p-aminobenzoic acid at high concentrations can interact with dihydrofolate reductase. The antibacterial activity of p-aminobenzoic acid at high concentrations is considered to be a blocking effect on dihydrofolate reductase even though p-aminobenzoic acid at low concentrations is an essential part of the synthesis of dihydrofolic acid. These findings support an alternative hypothesis for the mechanism of antibacterial action of individual antifolates and their mechanism of synergism in combination.

4-Aminobenzoic Acid↗
PubMed1997

Quantification of benzocaine and its metabolites in channel catfish tissues and fluids by HPLC.

Methods for extraction and gradient HPLC quantification were developed for benzocaine (BZ) and three of its metabolites to be used in conjunction with a reverse isotope technique. The metabolites were p-aminobenzoic acid (PABA), acetyl-p-aminobenzoic acid (AcPABA) and acetylbenzocaine (AcBZ). The matrixes studied were white muscle, red muscle, skin, liver, trunk kidney, head kidney, plasma and the bile of channel catfish. Analytes were validated for each of the compounds at 25 and 100 nmol per sample in the various tissues and fluids. The intraday variability (R.S.D.) was less than 13% in all tissues and fluids except for BZ in the liver. Recoveries varied from matrix to matrix for each analyte. The highest recoveries were obtained from plasma which ranged from 82.8-99.8% depending on the concentration. The average recovery of the compounds from tissues was between 50 and 78%, except for liver where the recovery of PABA and BZ was below 30%. Detection was by UV absorbance at 286 nm and the linear range was 2.5-15 nmol 100 ml-1 for all analytes. The method was selective; no interference peaks coeluted with the analytes.

4-Aminobenzoic Acid↗
PubMed1984

Acyl pentapeptide lactone synthesis in actinomycin-producing streptomycetes by feeding with structural analogs of 4-methyl-3-hydroxyanthranilic acid.

Several structural analogs of 4-methyl-3-hydroxyanthranilic acid (4-MHA) that had been established as substrates of the 4-MHA-activating enzyme from Streptomyces chrysomallus (Keller, U., Kleinkauf, H., and Zocher, R. (1984) Biochemistry 23, 1479-1484) were fed in short term labeling experiments to cultures of two actinomycin-producing streptomycetes. Besides inhibition of actinomycin synthesis, the addition of 4-methyl-3-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-aminobenzoic acid, or 4-methyl-3-methoxy-benzoic acid induced the formation of novel compounds. The data indicate that these compounds are structural analogs of 4-MHA pentapeptide lactones, which are the most probable precursors of actinomycins (Katz, E. (1967) in Antibiotics II (Gottlieb, D., and Shaw, P. D., eds) pp. 276-341, Springer-Verlag, New York). Since the structural analogs of 4-MHA are missing the o-aminophenol configuration, the corresponding acyl pentapeptide lactones cannot react with each other to give phenoxazines. Therefore, they accumulate and thus become detectable. Feeding cultures with 4-MHA resulted in an inhibition of actinomycin synthesis apparently at the level of acyl pentapeptide lactone synthesis. In such experiments, the formation of pentapeptide lactones, which are most likely derived from 4-MHA pentapeptide lactones, could be detected. The results provide experimental evidence that the biosynthesis of actinomycins proceeds via the 4-MHA-pentapeptide lactones.

Amino Acids↗
PubMed1982

Biochemical characterization of genetically variant aromatic amine N-acetyltransferases in A/J and C57BL/6J mice.

Biochemical genetic studies to determine the molecular basis for the differences in N-acetylation between the A/J and C57BL/6J mouse strains were carried out. Purification of liver N-acetyltransferase from both strains showed that aminofluorene and p-aminobenzoic acid activities are not separable by protein purification techniques which exploit differences in charge and size. In addition, both aminofluorene and p-aminobenzoic acid N-acetyltransferase activities from the C57BL/6J mouse liver enzymes migrated as a single symmetrical protein band after polyacrylamide disc gel electrophoresis. For aminofluorene and p-aminobenzoic acid, the two mouse strains showed apparent Km differences which suggest a difference in a structural gene product, and at least may partially account for the observed differences in N-acetylation. N-Acetyltransferase activity of selected extrahepatic tissues showed that both small intestine and kidney reflect the animal's phenotype as determined by liver or blood N-acetyltransferase. Sex differences were apparent in this activity in C57BL/6J mouse kidney, with males exhibiting approximately 2.5-fold higher activity for aminofluorene and approximately 3-fold higher activity for p-aminobenzoic acid than did females.

4-Aminobenzoic Acid↗
PubMed1994

Quantitative determination of monosaccharides in glycoproteins by high-performance liquid chromatography with highly sensitive fluorescence detection.

For specific determination of monosaccharides with high sensitivity, glycoprotein acid hydrolysates were derivatized in a simple step with excess anthranilic acid (2-aminobenzoic acid) in the presence of sodium cyanoborohydride to give highly fluorescent stable derivatives. The monosaccharide derivatives were completely separated from the excess reagent and from each other by HPLC on a C-18 reversed-phase column using a 1-butylamine-phosphoric acid-tetrahydrofuran mobile phase. Reductive amination of the monosaccharides in the methanol-acetate-borate medium was complete within 20 min at 80 degrees C. Derivatization of glucosamine with the anthranilic acid was accompanied by epimerization to mannosamine (> 15%) in methanol-acetic acid reaction medium, but it was reduced to < 3% in methanol-acetate-borate reaction medium. Fluorescence intensity of the hexosamines was greater than twice the intensity of the neutral monosaccharides. The fluorescent derivatives had excitation maxima at 230, 245, and 360 nm and an emission maximum at 425 nm. Fluorescence intensity at 230 nm excitation was about 10 times greater than that obtained with excitation at 360 nm for all the monosaccharides. Release and concomitant destruction of the monosaccharides during hydrolysis in 20% TFA at 100 degrees C for 7-8 h resulted in 83-85% recovery of all the monosaccharides from glycoproteins. The monosaccharide compositions determined by this method were in excellent agreement with the expected values for a recombinant immunoglobulin and fetuin and were highly reproducible. Relative standard deviation for the composition determinations and precision was less than 3%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2004

Analysis of fluorescently labeled glycosphingolipid-derived oligosaccharides following ceramide glycanase digestion and anthranilic acid labeling.

Interest in cellular glycosphingolipid (GSL) function has necessitated the development of a rapid and sensitive method to both analyze and characterize the full complement of structures present in various cells and tissues. An optimized method to characterize oligosaccharides released from glycosphingolipids following ceramide glycanase digestion has been developed. The procedure uses the fluorescent compound anthranilic acid (2-aminobenzoic acid; 2-AA) to label oligosaccharides prior to analysis using normal-phase high-performance liquid chromatography. The labeling procedure is rapid, selective, and easy to perform and is based on the published method of Anumula and Dhume [Glycobiology 8 (1998) 685], originally used to analyze N-linked oligosaccharides. It is less time consuming than a previously published 2-aminobenzamide labeling method [Anal. Biochem. 298 (2001) 207] for analyzing GSL-derived oligosaccharides, as the fluorescent labeling is performed on the enzyme reaction mixture. The purification of 2-AA-labeled products has been improved to ensure recovery of oligosaccharides containing one to four monosaccharide units, which was not previously possible using the Anumula and Dhume post-derivatization purification procedure. This new approach may also be used to analyze both N- and O-linked oligosaccharides.

Chromatography, High Pressure Liquid↗
PubMed1980

Inheritance of acetylator phenotype in mice.

The inheritance of two acetylator traits in a new mouse model of the human isoniazid acetylator polymorphism has been characterized. A/J mice have little or no blood p-aminobenzoic acid N-acetyltransferase activity and can excrete a low ratio of acetylsulfamethazine to sulfamethazine in urine. C57BL/6J mice have considerable blood p-aminobenzoic acid N-acetyltransferase activity and can excrete a high ratio of acetylsulfamethazine to sulfamethazine in urine. The expression of the blood p-aminobenzoic acid acetylation trait in F1, F2 and backcross progeny from A/J and C57BL/6J matings is consistent with simple Mendelian inheritance of two codominant alleles. Inheritance of in vivo acetylation rate, as measured by urinary ratio of acetylsulfamethazine to sulfamethazine, is independent of the blood acetylator polymorphism and is probably governed by simple Mendelian inheritance with incomplete dominance of low urinary ratio over high. Incomplete dominance appears to be limited to animals bearing one or two genes for rapid acetylation of p-aminobenzoic acid by blood hemolysates.

4-Aminobenzoic Acid↗
PubMed1987

Metabolism of benoxinate in humans.

The metabolism of benoxinate hydrochloride [2-(diethylamino)ethyl 4-amino-3-butoxybenzoate monohydrochloride; oxybuprocaine] was examined in humans after administration of a single oral dose. The drug was almost completely absorbed and was rapidly excreted in the urine (92.1% of dose in 9 h). Nine metabolites and unchanged drug were isolated from the urine and identified by comparison of TLC, GC, and GC-MS with authentic compounds. Any metabolites reflecting initial loss of the butyl side chain of benoxinate could not be detected. This suggests that the ester portion is metabolized more rapidly than the O-butyl side chain. 3-Butoxy-4-aminobenzoic acid, the hydrolyzed product of benoxinate, was primarily excreted (70-90% of dose) as the glucuronide together with a trace of the glycine conjugate (0.35% of dose). In addition, 3-butoxy-4-acetylaminobenzoic acid, 3-hydroxy-4-aminobenzoic acid, and 3-hydroxy-4-acetylaminobenzoic acid were identified, the latter two being detected partly as the glucuronides (1.20 and 1.43% of dose, respectively).

Anesthetics, Local↗
PubMed2001

Indigo degradation with purified laccases from Trametes hirsuta and Sclerotium rolfsii.

The degradation of the textile dye indigo with purified laccases from the fungi Trametes hirsuta (THL1 and THL2) and Sclerotium rolfsii (SRL1) was studied. All laccases were able to oxidize indigo yielding isatin (indole-2,3-dione), which was further decomposed to anthranilic acid (2-aminobenzoic acid). Based on the oxygen consumption rate of the laccases during indigo degradation, a potential mechanism for the oxidation of indigo involving the step-wise abstraction of four electrons from indigo by the enzyme was suggested. Comparing the effect of the known redox-mediators acetosyringone, 1-hydroxybenzotriazole (HOBT) and 4-hydroxybenzenesulfonic acid (PHBS) on laccase-catalyzed degradation of indigo, we found a maximum of about 30% increase in the oxidation rate of indigo with SRL1 and acetosyringone. The particle size of indigo agglomerates after laccase treatment was influenced by the origin of the laccase preparation and by the incubation time. Diameter distributions were found to have one maximum and compared to the indigo particle size distribution of the control, for all laccases, the indigo agglomerates seemed to have shifted to smaller diameters. Bleaching of fabrics by the laccases (based on K/S values) correlated with the release of indigo degradation products.

Basidiomycota↗
PubMed2002

Interactions of cyclodextrins with aromatic compounds studied by vibrational circular dichroism spectroscopy.

The host/guest complexation between cyclodextrins (CDs) and aromatic compounds was studied by vibrational circular dichroism (VCD) spectroscopy in mid-IR region. Benzoic acid, 4-aminobenzoic acid, and 2,6-naphthalene-dicarboxylic acid acting as the guests with aromatic skeleton, cause the significant changes in VCD patterns of CD, which indicate that the secondary hydroxyl groups of the CDs are involved in the host/guest complexation. In addition, the intensities and dissymmetry factors (deltaA/A) of the VCD bands, which belong to skeletal CD vibrations, depend on the sizes of the guest molecules. Our results indicate that the formation of the CD inclusion complexes can be followed by VCD spectroscopy.

Benzoates↗
PubMed1987

Sunscreens suppress cutaneous vitamin D3 synthesis.

Sunscreens block the cutaneous absorption of UV-B radiation and prevent sunburning, premature aging, and cancer of the skin. Inasmuch as UV-B radiation is also responsible for the photosynthesis of vitamin D3, we investigated the effect of sunscreens on the cutaneous formation of vitamin D3 in vivo and in vitro. Eight normal subjects, four of whom had been protected with the sunscreen para-aminobenzoic acid (sun protection factor 8), were exposed to one minimal erythema dose of UV radiation. The mean serum vitamin D3 concentration increased from 1.5 +/- 1.0 (+/- SEM) to 25.6 +/- 6.7 ng/mL in unprotected subjects, whereas it was 5.6 +/- 3.0 and 4.4 +/- 2.4 ng/mL at these times in the subjects who were protected with para-aminobenzoic acid. Para-aminobenzoic acid also prevented the photoisomerization of 7-dehydrocholesterol to previtamin D3 in human skin slices in vitro. These results indicate that the sunscreen interferred with the cutaneous production of vitamin D3.

4-Aminobenzoic Acid↗
PubMedDate not supplied

N-acetylation pharmacogenetics. Michaelis-Menten constants for arylamine drugs as predictors of their N-acetylation rates in vivo.

Michaelis-Menten constants for two in vivo monomorphically N-acetylated substrates, p-aminobenzoic acid and p-aminosalicylic acid, and two in vivo polymorphically N-acetylated substrates, sulfamethazine and procainamide, were determined with an improved assay procedure using liver N-acetyltransferase from rapid and slow acetylator rabbit. The slow rabbit liver isozyme proves to be a Vmax and a Km variant for p-aminobenzoic acid and p-aminosalicylic acid. Mean differences in the apparent Vmax for rapid acetylators were 39-fold greater for p-aminobenzoic acid and 16-fold greater for p-aminosalicylic acid. The apparent Km values for the slow acetylator enzyme were lower than 5 microM, whereas the apparent Km values for the rapid acetylator phenotype were at least 15 times higher, with a value of 105 +/- 21 microM for p-aminobenzoic acid and 74 +/- 16 microM for p-aminosalicylic acid. In contrast, for the polymorphic substrates, sulfamethazine and procainamide, rapid rabbit liver N-acetyltransferase was only a Vmax variant with a mean specific activity that was 13-fold higher than that for slow acetylator.

4-Aminobenzoic Acid↗
PubMed1990

Absorption and metabolism of procaine by the rat small intestine.

The aim of this study was to obtain information about the absorption of procaine in the rat small intestine (Fisher-Parsons preparation). In the range from 0.25-10 mmol.l-1 procaine in the luminal perfusate, much more of the unchanged drug was absorbed in segments of the ileum than of the duodenum and jejunum. Besides procaine, two metabolites, p-aminobenzoic acid (PABA) and acetylated p-aminobenzoic acid (AABA), formed in the intestinal mucosa, appeared in the absorbate. With increasing substrate concentration in the perfusate the PABA in the absorbate increased considerably in all three segments; from 0.75 mmol.l-1 procaine upwards the PABA produced was highest in the jejunum. AABA formed in the mucosa and measured in the absorbate did not increase in the same manner with increasing substrate concentration; in the absorbate of jejunal segments the amount of AABA was significantly higher than in duodenal and ileal segments. Taking into account that in rats the microclimate of the ileum differs considerably from that of the upper part of the small intestine, the marked difference observed in the absorption of procaine between ileal segments on the one side, and duodenal and jejunal segments on the other, can be explained on the basis of the "non-ionic diffusion" theory.

4-Aminobenzoic Acid↗