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PubMedDate not supplied

[The interorgan distribution of tritium-labelled para-aminobenzoic acid in the body of rats after its subcutaneous injection].

To study the pharmacokinetics of para-aminobenzoic acid (PABA), rats were subcutaneously injected with 3H-PABA (1 mkg/g body weight) at the stage (P7) when stimulation of outer segments of the photoreceptor cell morphogenesis is possible (Stroeva et al., 1990). The maximum labelling assayed for radioactivity by scintillation counting was observed in the liver 3 h after the injection while, in the blood the labelling was 3 times lower and, in the retina, one order lower than in the liver and blood. The label was detected in all the three types of tissue in 24 and 48 hours, being reduced by an order in comparison with each previous term of measurement. Biological structures binding 3H-PABA were not determined in the present study.

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PubMed1985

Bentiromide test for assessing pancreatic dysfunction using analysis of para-aminobenzoic acid in plasma and urine. Studies in cystic fibrosis and Shwachman's syndrome.

We evaluated the bentiromide test by analyzing para-aminobenzoic acid (PABA) in plasma and urine (a) for the identification of patients with complete pancreatic insufficiency and (b) as an alternative to the secretin-cholecystokinin test. Nine control subjects, 18 patients with cystic fibrosis, and 4 patients with Shwachman's syndrome were studied. Based upon the secretin-cholecystokinin test, pancreatic function was judged to be less than 0.1% of normal in 7 patients with cystic fibrosis and malabsorption and between 0.7% and 90% of control values in 11 patients with cystic fibrosis and 4 patients with Shwachman's syndrome without malabsorption. The bentiromide test was performed in two stages: first with bentiromide alone, then with equimolar free PABA. After ingestion of free PABA, the plasma profile and urinary excretion of PABA were comparable in controls, patients with cystic fibrosis, and patients with Shwachman's syndrome. Thirty minutes after oral bentiromide, plasma PABA values in patients with and without malabsorption were significantly lower than in the control group. From 60 to 180 min after ingestion, plasma PABA levels in patients without malabsorption were no different from controls; whereas levels in patients with malabsorption were significantly lower than in controls and in those without malabsorption, reaching the highest significance at 90 min. Similar results were obtained when the urinary excretion of PABA was considered. Only the 90-min plasma test reliably detected cystic fibrosis patients with steatorrhea, however. Duodenal colipase output was highly correlated with both the 90-min plasma test and the urinary excretion of PABA, with similar results for lipase and trypsin output. Reliable detection of pancreatic dysfunction, nevertheless, was not obtained even with the plasma test, in cystic fibrosis patients with greater than 5%-10% of the mean normal enzyme output. In patients with Shwachman's syndrome, none of whom had malabsorption, the plasma and urinary test failed to detect pancreatic dysfunction even with enzyme output as low as 1% of normal.

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PubMed2005

Potential-dependent adsorption and orientation of a small zwitterion: p-aminobenzoic acid on Ag(111).

We report on the potential-dependent behavior of the zwitterionic molecule p-aminobenzoic acid (PABA) at a Ag(111) electrode surface. Infrared-visible sum frequency generation spectroscopy (SFG) in tandem with electrochemical capacitance and CV measurements are used to study the effects of applied potential on the adsorption and orientation of PABA. Changes in the SFG signal indicate that PABA changes orientation in response to the charge on the electrode surface, orienting one way positive of the potential of zero charge (pzc) and oppositely negative of the pzc. At positive potentials, a phase change is observed associated with the formation of a condensed layer. PABA is observed to remain on the surface at all potentials examined. These results show that the orientation of small molecules with large dipoles, like zwitterions, can be controlled by applied potential.

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PubMed1982

[Repair effect of p-aminobenzoic acid and aminobenzhydrazide].

A simple, safe and rapid experimental scheme is offered for screening chemical compounds for ability to activate DNA reparation in bacterial cells. As DNA-damaging agent use was made of cell heating. The structural integrity of genome was determined during subsequent 90-minute incubation of bacteria. It was demonstrated that without additions to the culture medium, the cells are unable to recover the damaged genome, while addition of the compounds in question stimulated the reparation of bacterial DNA. p-Aminobenzoic acid (10(-5) M) was more powerful than aminobenzhydrazide as regards the recovery of genome integrity.

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PubMed1983

[Selective effect of p-aminobenzoic acid on mutagenesis: phenotypic analysis of the Arg+-revertants induced by N-nitroso-N-methylurea in the Escherichia coli K-12 AB1157 strain].

According to the phenotypic analysis of Arg+ revertants in Escherichia coli K-12 AB1157, the specific mutational changes in bacterial cells under the action of MNU were registered. True and suppressor mutations of four phenotypic groups were noted. The quantity of mutants induced depended upon the DNA and protein syntheses in bacterial cells. The sublethal concentration of para-aminobenzoic acid markedly (10-50 fold) reduced the rate of mutagenic induction and changed the quantity relations of mutants within phenotypic groups.

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PubMed2001

[Effects of para-aminobenzoic acid (PABA) on growth of Streptococcus mutans].

OBJECTIVE: The aim of this study is to examine effects of para-aminobenzoic acid (PABA) on the growth of Streptococcus mutans (S. mutans). METHODS: Different concentrations of PABA (10(-10)-10(-3) g/L) were separately transferred to modified Carlsson medium. S. mutans (ATCC 25175) grew in modified Carlsson medium with different concentrations of PABA. All cultures were incubated at 37 degrees C anaerobically in an atmosphere of 80% of nitrogen (v/v), 10% of hydrogen (v/v) and 10% of carbon dioxide (v/v) for 48 hours. The absorbance values of S. mutans were measured by using a spectrometer (UV-1601). The colony forming units (CFU) were obtained by growing S. mutans in media with different concentrations of PABA (10(-10)-10(-3) g/L). RESULTS: Different concentrations of PABA had different stimulating effects on the growth of S. mutans (P < 0.05). But this kind of stimulating effects declined when the concentration of PABA was 10(-3) g/L. CONCLUSION: This experiment indicates PABA has stimulating effects on the growth of S. mutans, and PABA can promote growth of S. mutans.

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PubMed2001

[Effects of para-aminobenzoic acid (PABA) on growth of Lactobacillus acidophilus].

OBJECTIVE: The aim of this study is to examine effects of para-aminobenzoic acid (PABA) on the growth of Lactobacillus acidophilus (L. acidophilus). METHODS: Different concentrations of PABA (10(-10)-10(-3) g/L) were separately transferred to the modified Carlsson medium. L. acidophilus (ATCC4356) grew in these Carlsson media. All cultures were incubated at 37 degrees C anaerobically in atmosphere of 80% of nitrogen, 10% of hydrogen, and 10% of carbon dioxide for 48 hours. Absorbance values (lambda = 540 nm) of bacterial suspensions were measured using a spectrometer (UV-1601). Colony forming units (CFU) were obtained by growing L. acidophilus in Carlsson media with different concentration of PABA (10(-10)-10(-3) g/L). RESULTS: Different concentrations of PABA (10(-10)-10(-4) g/L) had different stimulating effects on the growth of L. acidophilus (P < 0.05). But stimulating effects declined, when PABA concentration was 10(-5) g/L, and when the concentration of PABA reached 10(-3) g/L, the stimulating effect disappeared. CONCLUSION: This study indicates PABA stimulates the growth of L. acidophilus, and PABA can promote growth of L. acidophilus.

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PubMed2000

[A comparative study on the capacities of different strains of Streptococcus sanguis for P-aminobenzoic acid production].

This study was intended to compare the capacities of different strains of Strep, sanguis for P-Aminobenzoic acid (PABA) production. The synthesis of PABA during the growth of four strains of Strep. sanguis was measured by the reversed-phase high-performance liquid chromatographic method. The results showed that the concentrations of PABA synthesized by S. sanguis 10556, S. sanguis 10557, S. sanguis S34 and S. sanguis H7-4. Were 1.979 +/- 0.081 micrograms/ml, 1.383 +/- 0.193 micrograms/ml, 1.983 +/- 0.052 micrograms/ml and 1.032 +/- 0.229 micrograms/ml, respectively, and in term of PABA concentration, S. sanguis 10556 was significantly different from S. sanguis 10557 and S. sanguis H7-4; S. sanguis S34 was significantly different from S. sanguis 10557 and S. sanguis H7-4. No significant difference was found between S. sanguis 10556 and S. sanguis S34, nor between S. sanguis 10557 and S. sanguis H7-4, either. In conclusion, the method is simple, rapid and accurate. S. sanguis did synthesize PABA, and the difference in ability for PABA formation existed among the four strains of S. sanguis. This study is helpful to researches on the symbiosis between S. sanguis and S. muntans and to determination of their role in the microbial homeostasis of dental plaque.

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PubMed1952

The isolation and identification of para-aminobenzoic acid produced by staphylococci resistant to sulfonamide.

Previous studies have shown that when Staphylococcus aureus becomes resistant to sulfonamides, an antisulfonamide substance is produced in the growth medium. Although these studies suggested that the substance was p-aminobenzoic acid (PABA), isolation and positive identification were not achieved. Because of the importance of these observations, unequivocal identification of the product was attempted. A strain of Stapkylococcus aureus resistant to sulfonamides was cultivated on a simplified medium, the organisms separated in a Sharples centrifuge and the diazotisable amine absorbed on amberlite IR-120 previously acidified. Elution was accomplished with pyridine and the amine recovered by ether extraction at pH 3.7. Paper chromatography revealed one amine resembling PABA and another contaminating diazotizable amine present in very small amounts. The PABA-like amine was further separated by chromatography; its R(f) value and its spectrum in the ultraviolet then equalled those obtained with PABA. A 2,4-dlnltrophenyl derivative of the amine was prepared and the m.p. was similar to that of the derivative made from PABA. On the basis of the physical and chemical properties described, it would appear unequivocal that this bacterial amine is PABA.

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PubMed1983

[para-Aminobenzoic acid inhibits the manifestation of inducible SOS functions in Escherichia coli K-12].

In experiments with chemical mutagens (alkylating agents MNU, ENU, MMS and EMS), para-aminobenzoic acid (PABA) sharply inhibited the inducible processes in Escherichia coli, namely, mutagenesis, induction of lambda prophage and W-reactivation of UV-irradiated phage lambda. Based on experimental studies of E. coli strains deficient in different steps of DNA repair, the conclusion was made that PABA participates in regulation of the branch of DNA repair that is controlled by recA+ recF+ alleles.

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