Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “AMINOBENZOIC ACID”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,153 records · Page 64Linked to original sources
PubMed2001

Effect of norcantharidin on N-acetyltransferase activity in HepG2 cells.

The inhibition ofarylamine N-acetyltransferase (NAT) activity by norcantharidin (NCTD), the demethylated form of cantharidin, in human hepatocellular carcinoma HepG2 cells was investigated. By using high performance liquid chromatography, NAT activity on acetylation of 2-aminofluorene (AF) and p-aminobenzoic acid (PABA) were examined. Two assay systems were performed, one with cellular cytosols, the other with intact HepG2 cell suspensions. The NAT activity in HepG2 cell line was inhibited by norcantharidin in a dose-dependent manner in both types of examined systems: i.e. the greater the concentration of norcantharidin in the reaction, the greater the inhibition of NAT activities. This report is the first to show that norcantharidin has an inhibitory effect on NAT activity in HepG2 cell.

4-Aminobenzoic Acid↗
PubMed2006

Drug evolution concept in drug design: 2. Chimera method.

The drug evolution method represents a novel approach towards efficient rational drug design by implementing the drug evolution concept to the creation and development of general chemical libraries with the purpose of allowing the identification of drug candidates with improved odds and lesser costs than the traditional drug design strategies. As another example of successful translation of the biological evolution into chemical evolution, the chimera method comprises the grafting of selected building blocks, identified through a basic search within a drug library, onto the same substitution sites on a rationally chosen scaffold. The method allows the creation of a library containing both drugs and prospective drug candidates without any priorly required knowledge on the pursued disease or molecular target. Two libraries having scaffolds derived from para-aminobenzoic acid and salicylic acid have exemplified the application of the chimera method. The validation of the method has been achieved through the high number of recognized drugs within the library, which exhibit in the same time a wide variety of therapeutic activities and interact with a broad spectrum of molecular targets. The drug-enriched chimera libraries are expected to provide a highly efficient access to novel drug candidates whose unspecified therapeutic effects should be further revealed through high-throughput screening.

4-Aminobenzoic Acid↗
PubMed1982

Sunscreens block the induction of epidermal ornithine decarboxylase by ultraviolet-B radiation: a new way of evaluating sunscreen efficacy in vivo.

Two proprietary sunscreen preparations containing para-aminobenzoic acid and sulisobenzone, respectively, were tested for their ability to block the induction of ornithine decarboxylase by medium wavelength ultraviolet radiation (UV-B) in the epidermis of the hairless mouse. Both preparations were effective, the sunscreen treated animals requiring more radiation for ornithine decarboxylase induction. The UV dose-dependent gradients were reduced by a mean factor of 7.35 (sulisobenzone) and 15 (PABA). These figures correlate well with other in vivo sunscreen assays. This new method provides a simple and reproducible way of evaluating sunscreens in vivo.

4-Aminobenzoic Acid↗
PubMed2004

Occurrence of antibiotic residues in milk from Manchega ewe dairy farms.

Ewe milk samples from different ovine dairy farms from the Castilla-La Mancha region of Spain were collected from bulk tanks to estimate the occurrence of antibiotic residues in raw and heated (82 degrees C, 10 min) milk by the Delvotest SP test. The month of collection, somatic cell counts, and bacteriology were analyzed and examined by means of a logistic regression model. The screening of a total of 2686 raw milk samples showed 1.7% "positive" and 2.1% "doubtful" results, which decreased after heating treatment to 1.3% and 0.4%, respectively. "Positive" and "doubtful" samples were identified by penicillinase and p-aminobenzoic acid solutions, and the majority of them corresponded to antimicrobials different than beta-lactams or sulfonamides. By applying a logistic regression model, a significant effect of month of collection and bacteriology was observed in the initial screening and after the heat treatment. The highest percentages of "positive plus doubtful" results were observed in late summer-early autumn. A slight peak was also observed in spring in raw milk samples. Bacteriology was positively correlated with "positive plus doubtful" results.

4-Aminobenzoic Acid↗
PubMed1986

Endocrine and exocrine pancreatic function in treated coeliac disease.

Pancreatic function was assessed prospectively in a group of 18 treated adult coeliac patients, most of whom were asymptomatic. The para-aminobenzoic acid (PABA) test indicated exocrine pancreatic insufficiency in three patients, all of whom had persisting gastrointestinal symptoms. Arginine, 5 g intravenously, was used to stimulate pancreatic islet cells; basal and stimulated concentrations of plasma insulin, C-terminal glucagon, N-terminal glucagon, and blood glucose did not differ from asymptomatic nondiabetic control subjects. After gluten withdrawal, coeliac patients who responded clinically had no evidence of significant pancreatic impairment, but consideration of exocrine pancreatic insufficiency is worthwhile in those patients with persisting symptoms.

4-Aminobenzoic Acid↗
PubMed1989

Host diet in experimental rodent malaria: a variable which can compromise experimental design and interpretation.

Over the past few years several experienced groups studying malaria have encountered significant problems with their particular rodent malaria-host system. This has involved, in some cases, periods during which the recovery of cryopreserved parasite stocks and growth of bloodstream parasites was markedly inhibited and, in other cases, periods of drastically increased mortality rates. The common factor linking these incidents was that they coincided with alterations in the experimental animal diet used. The inhibition of growth of cryopreserved stabilates or bloodstream parasites was abolished by supplementation with p-aminobenzoic acid (PABA) or by changing the diet used. Although the suppressive effects of diets lacking PABA on parasite growth have been known for over 30 years, the variation of PABA levels in modern laboratory animal feed concentrates is not well recognized. We have not established the exact cause of increased mortality, but it has been overcome by changing the diet used. We are documenting our experiences with this potential variable to forewarn workers in other laboratories of possible problems inherent in the use of different diets.

4-Aminobenzoic Acid↗
PubMed2000

Intraoperative radiation enhances decline of pancreatic exocrine function after pancreatic head resection.

Intraoperative radiation therapy has been introduced to improve survival rates after resection of biliopancreatic cancer. Early and late effects of intraoperative radiation on the exocrine and endocrine functions of the residual pancreas were examined in 54 patients with pancreatic head resection. Of the 54 patients, 20 underwent intraoperative radiation (A group) and the other 34 did not (B group). Fasting blood sugar level, a 120-min value of the 75-g oral glucose tolerance test, N-benzol-L-tyrosyl-p-aminobenzoic acid (BT-PABA) excretion value (a pancreatic exocrine function test), and amount of postoperative pancreatic juice drainage were compared between groups A and B at preoperative and early and late postoperative times. Fasting blood sugar level and a 120-min value of the 75-g oral glucose tolerance test (OGTT) showed no change at the early (<2 months) postoperative period of the two groups. At the late (>6 months) postoperative period, fasting blood sugar showed no alteration, while the 75-g OGTT 120-min value increased compared to the preoperative level in both groups. In the group A, the 75-g OGTT 120-min value at the late postoperative period was significantly higher than those at the preoperative and early postoperative periods (289.4 +/- 104.9 vs 193.0 +/- 58.2 mg/dl, P = 0.0198 and 289.4 +/- 104.9 vs 184.4 +/- 104.9 mg/dl, P = 0.0285). Preoperative BT-PABA excretion value was not different between the two groups. It decreased at the early postoperative period and returned to the preoperative level at the late postoperative period in both the groups. The decline of BT-PABA in group A was 23 +/- 21%, which was significantly larger than 11 +/- 24% in group B. The total amount of postoperative pancreatic juice drainage from postoperative days (POD) 4-13 in group A was about half as much as that in group B (720.8 +/- 916.4 vs 1433.8 +/- 962.1 ml, P = 0.0128). Univariate and multivariate regression analysis of factors concerning the decline of BT-PABA values at the early postoperative period showed that intraoperative radiation was a significant independent determinant. In conclusion, these results suggest that intraoperative radiation causes significant deterioration of pancreatic exocrine function at the early postoperative period. Intraoperative radiation for resectable periampullary carcinoma should be reappraised based on the decline of the pancreatic exocrine function as well as the improvement of the survival curve.

4-Aminobenzoic Acid↗
PubMed2006

The outcome of a long-term follow-up of pancreatic function after recovery from acute pancreatitis.

CONTEXT: It is generally assumed that pancreatic function recovers completely after mild but not after severe acute pancreatitis. OBJECTIVE: To evaluate both pancreatic function and quality of life in patients who had recovered from acute pancreatitis in a long-term follow-up study. PARTICIPANTS: Thirty-four patients (mean age: 56 years) who had recovered from biliary (n=26) or post ERCP (n=8) acute pancreatitis. The mean time after the event was 4.6 years. MAIN OUTCOME MEASURES: Pancreatic function was evaluated by fecal fat excretion, urinary 4-aminobenzoic acid (PABA) recovery, oral glucose tolerance test and pancreatic polypeptide (PP) secretion. In addition, the quality of life was measured by the gastrointestinal quality of life index (GIQLI). RESULTS: Of the 34 patients, 22 (65%) had mild and 12 (35%) had severe acute pancreatitis. Exocrine insufficiency (fecal fat greater than 7 g/24h and/or urinary PABA recovery less than 50%) was present in 22 (65%) patients: in 10 (83%) after severe and in 12 (55%) after mild acute pancreatitis, respectively (P=0.140). Endocrine insufficiency was present in 12 patients (35%): 7 (32%) mild versus 5 (42%) severe acute pancreatitis; P=0.711. the quality of life was significantly impaired after acute pancreatitis, (P=0.024). No significant relationship was found between the severity of the pancreatitis and impairment of the quality of life (P=0.604). CONCLUSION: In a significant proportion of patients who had recovered from acute pancreatitis, exocrine and endocrine functional impairment was found. This finding is not confined only to patients after severe acute pancreatitis. Routine evaluation of pancreatic function after acute pancreatitis should be considered.

4-Aminobenzoic Acid↗
PubMed1994

Acetylator phenotyping: the urinary caffeine metabolite ratio in slow acetylators correlates with a marker of systemic NAT1 activity.

Eighteen healthy Caucasians were evaluated for the systemic acetylation of a caffeine metabolite using the urinary caffeine metabolite ratio 5-acetylamino-6-formylamino-3-methyluracil (AFMU) to 1-methylaxanthine (1X) and for N-acetyltransferase activity in peripheral blood mononuclear leukocytes (MNL) using p-aminobenzoic acid (PABA). These are markers for systemic NAT2 and NAT1 N-acetyltransferase activities, respectively. Fourteen slow acetylators and four fast acetylators (the NAT2 polymorphism) were identified by the caffeine metabolite ratio. In slow acetylators who have decreased levels of hepatic NAT2, the AFMU/1X ratio was significantly correlated with PABA acetylation in MNL (r = 0.8; p = 0.0002). These results suggest that significant variation in the acetylation of arylamine substrates susceptible to the classical acetylator polymorphism is attributable to variation in NAT1 activity in the slow acetylator phenotype.

4-Aminobenzoic Acid↗
PubMed1990

Combined single day 14C-triolein breath test and PABA test in the diagnosis of malabsorption.

The 14C-triolein breath test, a recognised index of fat absorption, and the p-aminobenzoic acid (PABA) test, a 'tubeless' test of exocrine pancreatic function, have both been widely used in the diagnosis of malabsorption and exocrine pancreatic insufficiency. This study evaluates the potential of a combination of both tests in the investigation of fat absorption and exocrine pancreatic function. Combination of the tests has become technically feasible because of the introduction of high pressure liquid chromatography as the preferred method of analysis for PABA, and use of p-aminosalicylic acid (PAS) as the marker for PABA absorption and metabolism. We studied 25 healthy subjects, 11 patients with exocrine pancreatic disease and 12 patients with gastrointestinal disease. The combined test identified subjects with reduced fat absorption and distinguished subjects with exocrine pancreatic insufficiency from those with an intestinal cause of fat malabsorption. The test could be completed in 7 h and had high patient acceptability. These findings suggest that the combined 14C-triolein breath test and PABA test can be used as a non-invasive, 1-day investigation of fat absorption and exocrine pancreatic function.

4-Aminobenzoic Acid↗
PubMed1985

Biochemical investigation of the basis for the genetic N-acetylation polymorphism in the inbred hamster.

Cytosolic acetyl coenzyme A-dependent N-acetyltransferase enzyme (E.C. 2.3.1.5) from inbred hamsters of each acetylator genotype was partially purified by ion-exchange chromatography. Two distinct N-acetyltransferase enzymes were identified; the first one exhibited a polymorphic expression across acetylator genotypes whereas the second exhibited a monomorphic expression. The monomorphic enzyme had consistently high isoniazid and procainamide N-acetyltransferase activity in homozygous rapid acetylator (Bio. 87.20), homozygous slow acetylator (Bio. 82.73/H), obligate heterozygous rapid acetylator F1 progeny and in each of the three acetylator genotypes of F2 progeny. In contrast, the polymorphic enzyme exhibited marked acetylator genotype-dependent N-acetyltransferase activity. High p-aminobenzoic acid N-acetyltransferase activity was exhibited in the homozygous rapid acetylator parental and F2 generation progeny, intermediate activity was exhibited in the heterozygous rapid acetylator F1 and F2 generation progeny and very low or nondetectable activity was exhibited in homozygous slow acetylator parental and F2 generation progeny. A similar gene dose-response relationship was exhibited by the polymorphic N-acetyltransferase enzyme toward isoniazid and procainamide. These results provide new insight into the biochemical basis for the substrate-dependent polymorphic and monomorphic expression of N-acetylation capacity in the inbred hamster.

4-Aminobenzoic Acid↗
PubMed2000

N-Acetylation of paraphenylenediamine in human skin and keratinocytes.

Skin is the major target of allergic reactions to paraphenylenediamine (PPD). Such small molecules require activation to become immunogenic. The balance between activation and/or detoxification processes is critical for immunogenic potentials of compounds. Therefore, we investigated N-acetylation (NAT) capacities of human skin for PPD to gain a better understanding of its mechanisms of action. PPD is acetylated to monoacetyl-PPD (MAPPD), which in turn is acetylated to N,N'-diacetyl-PPD (DAPPD). This was found using cytosolic fractions from human skin (n = 9) and cultured normal human epidermal keratinocytes (n = 7). The cutaneous activities for MAPPD formation ranged from 0.41 to 3.68 nmol/mg/min (9-fold variation) and DAPPD formation from 0.65 to 3.25 nmol/mg protein/min (5-fold), respectively. Similar results were obtained with keratinocytes. NAT activities toward both substrates, PPD and MAPPD, were correlated in keratinocytes (r = 0.930), suggesting that the reactions were catalyzed by the same enzyme. Formation of MAPPD and DAPPD was competitively inhibited in the presence of p-aminobenzoic acid (300 microM), a typical NAT1 substrate, but not by sulfamethazine. These kinetic characteristics suggest that the acetylation of PPD in human skin and keratinocytes is predominantly attributable to the polymorphic NAT1, although both mRNAs (NAT1 and NAT2) are synthesized in human skin and keratinocytes. The metabolism of PPD by NAT1 in human skin and keratinocytes as well as the virtual absence of NAT2 activity may have important toxicological implications. In the case of PPD, our results emphasize that N-acetylation status may be a susceptibility factor for the development of an allergy to PPD.

4-Aminobenzoic Acid↗
PubMed1987

Specific Vinca alkaloid-binding polypeptides identified in calf brain by photoaffinity labeling.

A radioactive, photoactive Vinca alkaloid, N-(p-azido-[3,5-3H]-benzoyl)-N'-beta-aminoethylvindesine [( 3H]NABV) with pharmacological and biological activities similar to vinblastine was synthesized and used to identify specific Vinca alkaloid macromolecular interactions in calf brain homogenate by photoaffinity labeling. The most prominent photolabeled species were 54.3- and 21.5-kDa polypeptides. The Vinca alkaloid-binding specificity of these polypeptides was confirmed by competitive blocking of specific photolabeling by vinblastine but not by colchicine or daunorubicin. The 54.3- and 21.5-kDa polypeptides exhibited specific half-maximum saturable photolabeling at 2.1 and 0.95 X 10(-7) M [3H]NABV, respectively. Relative vinblastine and NABV association constants (Ka vinblastine/Ka NABV) for the 54.3- and 21.5-kDa polypeptides were estimated to be 0.86 and 1.4, respectively. The 54.3-kDa component was found in both high speed (100,000 X g; 1 h) pellet and supernatant fractions, whereas the 21.5-kDa component was located primarily in the high speed pellet. Photolabeling of both components was maximal after 12-min UV light exposure, linear up to 120 micrograms of homogenate protein and only slightly affected by the nitrene scavenger p-aminobenzoic acid. The 54.3-kDa polypeptides of [3H]NABV-photolabeled calf brain high speed supernatant and detergent-solubilized high speed pellet fractions were identified as tubulin subunits by immunoprecipitation with monoclonal antibodies to alpha- or beta-tubulin subunits. Although the identity and function of the 21.5-kDa polypeptide is not known, this polypeptide may have a role in membrane-related effects of the Vinca alkaloids. These results demonstrate that [3H]NABV is an attractive tool for identifying and characterizing specific high affinity vinblastine cellular polypeptide acceptors which may initiate or mediate known and unknown mechanisms of Vinca alkaloid action.

4-Aminobenzoic Acid↗
PubMed2001

Which is a less invasive pancreatic head resection: PD, PPPD, or DPPHR?

Less invasive pancreatic head resection, such as pylorus preserving pancreatoduodenectomy (PPPD) and duodenum preserving pancreatic head resection (DPPHR) has been introduced for the treatment of pancreatoduodenal lesions, especially for benign conditions, in consideration of postoperative quality of life. Surgical stress and exocrine and endocrine function of the residual pancreas were examined in 44 patients with PPPD, 10 with conventional pancreatoduodenectomy (PD) and six with DPPHR. Clinical findings including serum levels of C reactive protein (CRP), fasting blood sugar, a 120-min value of the 75-g oral glucose tolerance test (OGTT), N-benzol-L-tyrosyl-p-aminobenzoic acid (BT-PABA) excretion value (a pancreatic exocrine function test), and volume of postoperative pancreatic juice drainage were compared among the three different variants of pancreatectomy. Operation time and operative blood loss in PD were largest of the three, followed by PPPD and DPPHR. Postoperative elevation of serum CRP on postoperative day (POD) 2 or 3 was similar among the three different types of operation. Fasting blood sugar concentrations were not different among the three groups at short- and long-term after the operation, while the 120-min value of the GTT showed a marked elevation at long-term only after PPPD. The volume of pancreatic juice drainage increased up to POD 4 and became constant thereafter. The total amount of pancreatic juice drainage from POD 4 to 13 was smallest in PD (637 ml) followed by PPPD (1,255 ml) and DPPHR (1,431 ml). The BT-PABA value declined after PD (-20.3%, P = 0.0437) and PPPD (-20.2%, P = 0.0239) at short term, but not after DPPHR (8.2%). These findings suggest that the early impairment of the pancreatic exocrine function after PD and PPPD but not after DPPHR may indicate that the invasiveness of pancreatic head resection to the pancreatic functions is greater in PD and PPPD than in DPPHR.

4-Aminobenzoic Acid↗
PubMed1992

Pancreatic function following partial pancreatectomy and anastomosis of the pancreatic duct to the stomach or duodenum in dogs.

The effects of pancreatic duct anastomosis to stomach (stomach group) or duodenum (duodenal group) on pancreatic function were examined in dogs following two thirds pancreatectomy. Normal fasting blood glucose concentrations were maintained in both groups despite significant reductions in glucose tolerance in the stomach group, and reductions in fasting insulin and insulin peak response in both groups. Pancreatic exocrine function was significantly decreased in both groups, though plasma p-aminobenzoic acid (PABA) concentrations were generally higher in the duodenal group. A correlation was found between plasma trypsin-like immunoreactivity (TLI) and pancreatic weight. These results indicate that anastomosis of the pancreas to bowel can be undertaken with minimal postoperative complications and that the site of the anastomosis influences pancreatic function. They suggest that preservation of more than one third of the pancreas is required for optimal function. The complementary information provided by the PABA and TLI tests suggests their dual application will be clinically useful for the detection and characterisation of naturally occurring pancreatic diseases.

4-Aminobenzoic Acid↗
PubMed1979

Antimalarial activity of Floxacrine (HOE 991) I. Studies on blood schizontocidal action of Floxacrine against Plasmodium berghei, P. vinckei and P. cynomolgi.

Floxacrine (HOE 991), 7-chloro-10-hydroxy-3-(4-trifluoromethylphenyl)3,4-dihydroacridine-1,9-(2H, 10H) dion, shows a high level of antimalarial action against blood-induced infection of drug-sensitive and drug-resistant lines of Plasmodium berghei in mice, rats and Syrian hamsters. The drug is also a potent blood schizontocide against drug-sensitive P. vinckei strains in rodents and P. cynomolgi in rhesus monkeys. The CD50/CD90 values against the drug-sensitive P. berghei strain ascertained in the '28-day test' in mice were 4.3/6.7 mg/kg after the oral route and 1.7/3.6 mg/kg after the subcutaneous (sc) route. In the 'two- and four-day test' the ED50 against sensitive P. vinckei was 0.7 mg/kg in both mice and rats. A moderate prophylactic effect could be demonstrated after the sc route probably due to a 'depot effect' of the water-insoluble active principle. Floxacrine was also highly active against P. berghei-lines which were resistant to chloroquine, mepacrine, dihydrofolate reductase inhibitors, sulfadoxine and dapsone. Resistance to HOE 991 could be developed in P. berghei and P. cynomolgi when the compound was used alone and administered repeatedly in subcurative doses. The antimalarial activity of the compound was not influenced by p-aminobenzoic acid or folic acid supplements in diets. Structural changes induced by floxacrine on pigment cytoplasm and nucleus in erythrocytic stages of P. berghei differed in some aspects from those of mepacrine and chloroquine. It is therefore assumed that the mode of action of floxacrine differs from that of the known antimalarial drugs. The general tolerance of the compound in rodents and rhesus monkeys is good and there is a wide range between the effective and maximum tolerated doses. Floxacrine was also effective at 100 ppm against pathogen Eimeria species in chickens, at 1000 mg/kg orally against Fasciola hepatica in rats and at 300-800 mg/kg orally against Heterakis spumosa in rats.

4-Aminobenzoic Acid↗
PubMed2003

Effect of ultraviolet light absorbers on photostabilization of azadirachtin-A in solution (part: II).

The effect of photostabilization of azadirachtin-A (Aza-A) was examined in solutions when exposed to UV radiation, in the presence of four structurally different UV absorbers namely, p-aminobenzoic acid, 2,4-dihydroxybenzophenone, 4,4'-dihydroxybenzophenone and phenyl salicylate. The percentages of Aza-A recovered from the solutions after 6 h exposed to UV radiation in the presence and absence of UV absorbers indicated that the order of stabilization of Aza-A by these absorbers was similar to that obtained in the solid phase experiments in accordance with our previous observations. It is observed that the addition of phenyl salicylate in Aza-A (in 1:1 mole ratio) provides the excellent photostabilization of Aza-A molecule in solid phase as well as in solution among the four absorbers studied.

4-Aminobenzoic Acid↗