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1

Determination of p-aminobenzoic acid by room temperature solid surface phosphorescence  

Microsoft Academic Search

p-Aminobenzoic acid and several other molecules were found to phosphoresce at room temperature when adsorbed on sodium acetate. A unique phosphorimetric method is described for determining p-aminobenzoic acid without separation in multicomponent vitamin tablets. The reflected phosphorescence of p-aminobenzoic acid adsorbed on sodium acetate was measured in the quantitation step. The method is rapid, very selective, and sensitive for p-aminobenzoic

R. M. A. von Wandruszka; R. J. Hurtubise

1976-01-01

2

Paeonol promoted 2-aminofluorene and p-aminobenzoic acid acetylations by mononuclear leucocytes from Sprague-Dawley rats.  

PubMed

Following exposure of rats to the arylamine carcinogen 2-aminofluorene, DNA-carcinogen adducts were found in the target tissues of the liver and bladder, and also in circulating leucocytes. This work investigated how paeonol affects arylamine (2-aminofluorene and p-aminobenzoic acid) acetylations in rat leucocytes. Evidence is presented showing that rat mononuclear leucocytes are capable of acetylating 2-aminofluorene and p-aminobenzoic acid. Paeonol promoted 2-aminofluorene and p-aminobenzoic acid acetylation. Cultured lymphocytes produced about twice as much N-acetyl-2-aminofluorene from 2-aminofluorene and 2.2-fold as much N-acetyl-p-aminobenzoic acid from p-aminobenzoic acid as monocytes. After cotreatment with paeonol, the lymphocyte and monocyte cultures indicated that paeonol did increase 2-aminofluorene and p-aminobenzoic acid acetylations. PMID:11086710

Chang, H L; Hung, C F; Yeh, C C; Chang, W C; Chung, J G

2000-01-01

3

Growth of oriented p-aminobenzoic acid crystals by directional freezing.  

PubMed

Oriented long needle-like p-aminobenzoic acid (PABA) crystals are successfully prepared by directional freezing of PABA solution in this work. The width of the oriented crystals is controlled by changing the directional cooling rate, resulting in varying crystal morphologies and thermodynamic properties while maintaining the same chemical structure. PMID:23144588

Ko, Young Gun; Ma, Peter X

2012-09-26

4

Growth of oriented p-aminobenzoic acid crystals by directional freezing  

PubMed Central

Oriented long needle-like p-aminobenzoic acid (PABA) crystals are successfully prepared by directional freezing of PABA solution in this work. The width of the oriented crystals is controlled by changing the directional cooling rate, resulting in varying crystal morphologies and thermodynamic properties while maintaining the same chemical structure.

Ko, Young Gun

2012-01-01

5

Ellagic acid inhibited 2-aminofluorene and p-aminobenzoic acid acetylation by mononuclear leucocytes from Sprague-Dawley rats.  

PubMed

Following exposure of rats to the arylamine carcinogen 2-aminofluorene, DNA-carcinogen adducts were found in the liver and bladder target tissues, and also in circulating leucocytes. This work investigated the effect of ellagic acid on arylamine (2-aminofluorene and p-aminobenzoic acid) acetylations in rat leucocytes. Evidence is presented that rat mononuclear leucocytes are capable of acetylating 2-aminofluorene and p-aminobenzoic acid. Both lymphocytes and monocytes were able to acetylate arylamines during 18 h of culture. Cultured lymphocytes produced about twice as much N-acetyl-2-aminofluorene from 2-aminofluorene and 2.2-fold as much N-acetyl-p-aminobenzoic acid from p-aminobenzoic acid as monocytes. After cotreatment with ellagic acid the lymphocyte and monocyte cultures indicated that ellagic acid reduced 2-aminofluorene acetylation. PMID:11258539

Ho, C C; Tsai, H Y; Lai, Y S; Chung, J G

2001-01-01

6

Gravimetric determination of copper(II) with p-aminobenzoic acid.  

PubMed

A method has been developed for the gravimetric determination of 20-100 mg of copper(II) with p-aminobenzoic acid. Ag, Hg(II), Pb, Al, Fe(II), Bi, Sb(III) and Sn(II) interfere, but Zn, Co(II), Ni and Cd do not. The precipitate can be weighed after drying at 80-100 degrees , or can be ignited to copper(II) oxide at temperatures above 400 degrees , and weighed in this form. PMID:18960272

Erdey, L; Marik-Korda, P; Liptay, G

1968-01-01

7

Phosphorescence properties of p-aminobenzoic acid immobilized on a nylon membrane.  

PubMed

The properties of nylon as a new material for obtaining room-temperature phosphorescence from p-aminobenzoic acid (PABA) have been investigated. Although PABA shows native phosphorescence when adsorbed on a nylon membrane, a significant improvement in both sensitivity and limit of detection is achieved in the presence of alpha-cyclodextrin and heavy atoms. An additional enhancement of the phosphorescence signal is attained when the measurements are carried out under a nitrogen atmosphere. The analytical figures of merit obtained under the best experimental conditions are: linear calibration range from 0.6 to 6 ng/spot (the lowest value corresponds to the quantitation limit); correlation coefficient, 0.998 for 18 data points; relative standard deviation, 2.2% (n = 5) at a level of 2.4 ng/spot; and limit of detection, 0.2 ng/spot (calculated according to Clayton's definition). PMID:15282050

Escandar, Graciela M

2004-07-01

8

Auxotrophs of Plasmodium falciparum dependent on p-aminobenzoic acid for growth.  

PubMed Central

The isolation of auxotrophic strains of a parasite offers new opportunities for studying parasitology. We have isolated cloned lines of Plasmodium falciparum that, unlike the parent line from which they were derived, rely on exogenous p-aminobenzoic acid (PABA) for growth. Isolation involved random mutagenesis of a cloned line of P. falciparum and subsequent selection of PABA-dependent parasites. Both parent and PABA-dependent clones were analyzed for PABA uptake and synthesis. Each clone takes up comparable amounts of PABA from the medium. The parent line, clone 3D7, can synthesize PABA de novo, whereas the PABA-dependent clones cannot. The requirement of exogenous PABA for growth by the auxotrophic strains coupled with their inability to synthesize PABA indicates that normal parasite growth can be completely supported by either synthesis or salvage. This work further clarifies the relationship between the availability of PABA and success of the parasite, an issue of debate from classic studies showing reduced parasite load in individuals on milk-fed diets.

McConkey, G A; Ittarat, I; Meshnick, S R; McCutchan, T F

1994-01-01

9

Aquatic photodegradation of sunscreen agent p-aminobenzoic acid in the presence of dissolved organic matter.  

PubMed

Dissolved organic matter (DOM) is an important photosensitizer for the phototransformation of organic contaminants in sunlit natural waters. This article focuses on the photolysis kinetics and mechanism of sunscreen agent p-aminobenzoic acid (PABA) in the presence of four kinds of DOM; Suwannee River fulvic acid (SRFA), Suwannee River humic acid (SRHA), Nordic Lake fulvic acid (NOFA) and Nordic Lake humic acid (NOHA). It is evident that direct photolysis of PABA is highly pH-dependent because different species of PABA have different electrical densities on the ring system. The presence of four kinds of DOM inhibits the photolysis of PABA primarily due to their light screening effect. Meanwhile, a complex interaction involving energy transfer, triplet carbonyl group induced electron transfer, and amino acid induced proton abstraction between PABA and DOM is verified by competition kinetics experiments and density functional theory (DFT) computation. In addition, DOM-induced singlet oxygen ((1)O(2)) and hydroxyl radical (OH) are determined to play an insignificant role in PABA photolysis by competition dynamics method. Photoproducts identification using solid phase extraction-liquid chromatography-mass spectrometry (SPE-LC-MS) techniques reveals that the distribution of the photoproducts could not be affected by the addition of DOM. Two photodegradation pathways of PABA are temporarily proposed, in which the di(tri)-polymerization of intermediates are the dominant pathway whereas the oxidation of amino group to nitryl followed by hydroxylation is a minor process. Our findings reveal that direct photolysis is the dominant transformation pathway of PABA in natural sunlit waters, while the presence of DOM could evidently influence such process by light screening effect, energy transfer, electron transfer and proton abstraction mechanism. The findings in this study provide useful information for understanding of interaction between DOM and organic contaminants. PMID:23084339

Zhou, Lei; Ji, Yuefei; Zeng, Chao; Zhang, Ya; Wang, Zunyao; Yang, Xi

2012-10-04

10

Effects of temperature on the solid-surface luminescence properties of p-aminobenzoic acid adsorbed on sodium acetate  

SciTech Connect

Solid-surface fluorescence and phosphorescence quantum yield values were obtained from +23 to -180/sup 0/C for the anion of p-aminobenzoic acid adsorbed on sodium acetate. Phosphorescence lifetime values were also acquired for the adsorbed anion from +23 to -196/sup 0/C. The fluorescence quantum yield values remained essentially constant as a function of temperature; however, the phosphorescence quantum yield values changed substantially with temperature. The phosphorescence lifetime experiments indicated two decaying components, and each component showed a gradual increase in phosphorescence lifetime and then appeared to level off at lower temperatures. The results support a rigidly held mechanism for the room-temperature phosphorescence of the anion of p-aminobenzoic acid adsorbed on sodium acetate.

Ramasamy, S.M.; Hurtubise, R.J.

1987-02-01

11

Effects of temperature on the solid-surface luminescence properties of p-aminobenzoic acid adsorbed on sodium acetate  

Microsoft Academic Search

Solid-surface fluorescence and phosphorescence quantum yield values were obtained from +23 to -180°C for the anion of p-aminobenzoic acid adsorbed on sodium acetate. Phosphorescence lifetime values were also acquired for the adsorbed anion from +23 to -196°C. The fluorescence quantum yield values remained essentially constant as a function of temperature; however, the phosphorescence quantum yield values changed substantially with temperature.

S. M. Ramasamy; R. J. Hurtubise

1987-01-01

12

Photochemical formation of singlet molecular oxygen ( 1O 2) in illuminated aqueous solutions of p-aminobenzoic acid (PABA)  

Microsoft Academic Search

Evidence is presented for the photochemical formation of singlet molecular oxygen (1O2) in air-saturated buffered aqueous solutions of p-aminobenzoic acid (PABA) using sunlight-range illumination. This is significant because PABA is widely used as an active ingredient in sunscreen preparations that are applied to the surface of the skin and 1O2 is known to cause oxidative damage to cells via the

John M. Allen; Cindy J. Gossett; Sandra K. Allen

1996-01-01

13

Rapid Reaction of Singlet Molecular Oxygen ( 1O 2) with p-Aminobenzoic Acid (PABA) in Aqueous Solution  

Microsoft Academic Search

The reaction of singlet molecular oxygen (1O2) with p-aminobenzoic acid (PABA) is quite rapid. The rate constant for reaction of 1O2 with PABA was measured in buffered aqueous solution by the method of competition kinetics and found to be 8.9108 M?1 sec?1. The results of a Stern-Volmer analysis indicate that additional loss of 1O2 does not occur through physical quenching

J. M. Allen; S. Engenolf; S. K. Allen

1995-01-01

14

INHIBITION OF ESCHERICHIA COLI BY p-AMINOBENZOIC ACID AND ITS REVERSAL BY p-HYDROXYBENZOIC ACID  

PubMed Central

p-Aminobenzoic acid (PABA) exerts three metabolic effects on E. coli: it acts as a normal vitamin at low concentrations, as a source of another vitamin, p-hydroxybenzoic acid (POB), at moderate concentrations, and as a growth inhibitor at high concentrations (150 to 1600 g./ml.). The inhibition is competitively reversed by POB in 1/100 the concentration of PABA. The inhibition is also reversed to a limited extent by shikimic acid and compound X, precursors of POB. p-Nitrobenzoic acid is an inhibitory competitor of both POB and PABA. The retardation of growth produced by PABA and other competitive analogues of POB (p-nitrobenzoic acid; 4,4'-dihydroxydiphenyl sulfone; phenosulfazole) is converted to complete bacteriostasis by the addition of L-aspartic acid in a remarkably low concentration (1 g./ml.)) without change in the competitive ratio with POB. The mechanism underlying this synergism is not clear. In contrast to wild type, mutants that require POB not only are inhibited by much lower concentrations of the above analogues, but also show inhibition by weaker competitors of POB such as p-hydroxybenzenesulfonamide, p-chlorobenzoic acid, and p-fluorobenzoic acid.

Davis, Bernard D.

1951-01-01

15

Room-temperature phosphorescence lifetimes and intensities of p-aminobenzoic acid adsorbed on sodium acetate-sodium chloride mixtures  

SciTech Connect

Some of the interactions responsible for the room-temperature phosphorescence (RTP) of the p-aminobenzoic acid (PABA) anion adsorbed on sodium acetate-sodium chloride mixtures were elucidated by relative luminescence intensity and phosphorescence lifetime measurements. The luminescence intensity and phosphorescence lifetime values varied over a relatively wide range. The results showed that at least two mechanisms were involved for inducing RTP, with maximum RTP being achieved on pure sodium acetate. Short and long decaying phosphorescent components were detected from the PABA anion. Both of these components reached constant phosphorescence lifetime values even though the phosphorescence intensity continued to change as a function of the composition of phosphorescence-inducing solid-surface material. 16 references, 1 figure, 1 table.

Senthilnathan, V.P.; Hurtubise, R.J.

1985-06-01

16

Identification of a substance, previously shown to enhance mitogenesis of human lymphocytes, as the acetamide of p-aminobenzoic acid.  

PubMed

We characterize here an arachidonic acid (AA)-derived metabolite previously found to have an adjuvant effect in phytohemagglutinin-induced mitogenesis of lymphocytes from mothers of newborn babies and from immunodeficient infants. We named the metabolite 'compound 4' due to its position in a thin-layer chromatography system developed for isolation of eicosanoids. The compound was originally found to be produced by peripheral blood mononuclear leukocytes and the T cell leukemia line Jurcat after long-term (18-24 h) incubation with [1-14C]AA. Compound 4 is also produced by lymphocytes, monocytes, platelets, thrombocytes, cultured fibroblasts and various types of malignant cell lines. We purified this metabolite by means of high pressure liquid chromatography with synchronous detection of radioactivity and measurement of ultraviolet-light absorption at 278 nm. Proton nuclear magnetic resonance spectroscopy and mass spectrometry with electron impact techniques demonstrated that compound 4 is not an eicosanoid, but is identical to p-acetamidobenzoic acid (PACBA). The cells synthesize PACBA from p-aminobenzoic acid and a two-carbon residue from AA. PMID:7918614

Barbieri, B; Papadogiannakis, N; Eneroth, P; Hansson, C; Roepstorff, P; Olding, L B

1994-10-01

17

Room-temperature luminescence properties of p-aminobenzoic acid and 4-phenylphenol adsorbed on alpha-cyclodextrin\\/NaCl mixtures  

Microsoft Academic Search

The solid-surface fluorescence and phosphorescence quantum yield values and phosphorescence lifetime values were obtained for p-aminobenzoic acid (PABA) and 4-phenylphenol adsorbed on ..cap alpha..-cyclodexrin\\/NaCl mixtures. From the luminescence quantum yield and phosphorescence lifetime data, the triplet formation efficiency values, the phosphorescence rate constants, and the rate constants for radiationless transition from the triplet state were determined for PABA and 4-phenylphenol

J. M. Bellow; R. J. Hurtubise

1988-01-01

18

Residual Function of Exocrine Pancreas after Operation for Chronic Pancreatitis by N-Benzoyl-L-Tyrosyl-p-Aminobenzoic Acid Test (NBT-PABA Test)  

Microsoft Academic Search

The changes in the residual function of the exocrine pancreas before and after the operation for chronic pancreatitis were examined with N-benzoyl-L-tyrosyl-p-aminobenzoic acid (NBT-PABA test) in 15 patients. The results of the NBT-PABA test classified by the surgical formula proved that no significant difference was found between the pancreatectomized group (pancreaticoduodenectomy and distal pancreatectomy) and the decompression group (pancreatojejunostomy and

Motomu Kodama; Tsuneo Tanaka

1984-01-01

19

Comparative study of solid-matrix luminescence interactions of p-aminobenzoate on two different matrices  

Microsoft Academic Search

The luminescence properties of the anion of p-aminobenzoic acid adsorbed on sodium acetate and filter paper were compared to gain insights into the interactions that result in the fluorescence and phosphorescence of p-aminobenzoate. Fluorescence quantum yields, phosphorescence quantum yields, and phosphorescence lifetimes were obtained for the anion of p-aminobenzoic acid adsorbed on filter paper. Preexponential and activation energy terms were

S. M. Ramasamy; Robert J. Hurtubise

1990-01-01

20

Room-temperature luminescence properties of p-aminobenzoic acid and 4-phenylphenol adsorbed on. cap alpha. -cyclodextrin/NaCl mixtures  

SciTech Connect

The solid-surface fluorescence and phosphorescence quantum yield values and phosphorescence lifetime values were obtained for p-aminobenzoic acid (PABA) and 4-phenylphenol adsorbed on ..cap alpha..-cyclodexrin/NaCl mixtures. From the luminescence quantum yield and phosphorescence lifetime data, the triplet formation efficiency values, the phosphorescence rate constants, and the rate constants for radiationless transition from the triplet state were determined for PABA and 4-phenylphenol on ..cap alpha..-cyclodexctrin/NaCl mixtures. In addition, the percentages of radiative and nonradiative transitions were calculated for the two compounds. The various luminescence parameters obtained in this work provided important insights into the analyte/..cap alpha..-cyclodextrin substrate interactions responsible for the observed solid-surface room-temperature fluorescence (RTF) and phosphorescence (RTP). Furthermore, the RTF and RTP intensities of PABA and 4-phenylphenol were obtained from several ..cap alpha..-cyclodextrin/NaCl mixtures. The data showed the importance of the initial wet chemistry in the sample preparation procedure.

Bellow, J.M.; Hurtubise, R.J.

1988-05-01

21

[Improving the efficacy of synergetically facilitated pertraction of p-aminobenzoic acid by increasing the reextraction rate].  

PubMed

The studies on facilitated pertraction of PABA with Amberlite LA-2 and 1-octanol as phase modifier indicated the increase of the process efficiency and, implicitly, of the transport capacity of the liquid membrane by adding KOH in the stripping phase. Thus, the use of KOH led to the diminution of the kinetic resistance of the reextraction process, with positive effects on the acid final mass flow and permeability factor. Compared to the similar pertraction systems containing NaOH in the stripping phase and in direct correlation with the pertraction parameters (pH-gradient between the feed and stripping phases, carrier and alchohol concentrations inside the liquid membrane), the final mass flow can be accelerated for about 1.9 times, and the permeability through liquid membrane can be enhanced for about 1.5 times in presence of KOH. PMID:20509318

Kloetzer, Lenu?a; Galaction, Anca-Irina; Ca?caval, D

22

Interaction of P-aminobenzoic acid with normal and sickel erythrocyte membrane: photoaffinity labelling of the binding sites  

SciTech Connect

Electron microscopic studies revealed that P-Amino benzoic acid (PABA) could prevent eichinocytosis of red cells in vitro. Equilibrium binding studies with right side out membrane vesicles (ROV) revealed a similar number of binding sites (1.2-1.4 ..mu..mol/mg) and Kd (1.4-1.6 mM) values for both normal and sickle cell membranes. /sup 14/C-Azide analogue of PABA was synthesized as a photoaffinity label to probe its sites of interaction on the erythrocyte membranes. Competitive binding studies of PABA with its azide indicated that both the compounds share common binding sites on the membrane surface since a 20 fold excess of azide inhibited PABA binding in a linear fashion. The azide was covalently incorporated into the membrane components only upon irradiation (52-35% of the label found in the proteins and the rest in lipids). Electrophoretic analysis of photolabelled ROV revealed that the azide interacts chiefly with Band 3 protein. PABA inhibited both high and low affinity calcium (Ca) binding sites situated on either surface of the membrane in a non-competitive manner; however, Ca binding stimulated by Mg-ATP was not affected. Ca transport into inside out vesicles was inhibited by PABA; but it did not affect the calcium ATP-ase activity. The authors studies suggest that the mechanism of action of PABA is mediated by its interaction with Band 3 protein (anion channel), calcium channel and calcium binding sites of erythrocyte membrane.

Premachandra, B.R.

1986-03-05

23

Biochemical and genetic characterization of an early step in a novel pathway for the biosynthesis of aromatic amino acids and p-aminobenzoic acid in the archaeon Methanococcus maripaludis.  

PubMed

Methanococcus maripaludis is a strictly anaerobic, methane-producing archaeon and facultative autotroph capable of biosynthesizing all the amino acids and vitamins required for growth. In this work, the novel 6-deoxy-5-ketofructose-1-phosphate (DKFP) pathway for the biosynthesis of aromatic amino acids (AroAAs) and p-aminobenzoic acid (PABA) was demonstrated in M. maripaludis. Moreover, PABA was shown to be derived from an early intermediate in AroAA biosynthesis and not from chorismate. Following metabolic labelling with [U-(13)C]-acetate, the expected enrichments for phenylalanine and arylamine derived from PABA were observed. DKFP pathway activity was reduced following growth with aryl acids, an alternative source of the AroAAs. Lastly, a deletion mutant of aroA', which encodes the first step in the DKFP pathway, required AroAAs and PABA for growth. Complementation of the mutants by an aroA' expression vector restored the wild-type phenotype. In contrast, a deletion of aroB', which encodes the second step in the DKFP pathway, did not require AroAAs or PABA for growth. Presumably, methanococci contain an alternative activity for this step. These results identify the initial reactions of a new pathway for the biosynthesis of PABA in methanococci. PMID:17010158

Porat, Iris; Sieprawska-Lupa, Magdalena; Teng, Quincy; Bohanon, Fredrick J; White, Robert H; Whitman, William B

2006-09-29

24

In vitro reconstitution and crystal structure of p-aminobenzoate N-oxygenase (AurF) involved in aureothin biosynthesis  

Microsoft Academic Search

p-aminobenzoate N-oxygenase (AurF) from Streptomyces thioluteus catalyzes the formation of unusual polyketide synthase starter unit p-nitrobenzoic acid (pNBA) from p-aminobenzoic acid (pABA) in the biosynthesis of antibiotic aureothin. AurF is a metalloenzyme, but its native enzymatic activity has not been demonstrated in vitro, and its catalytic mechanism is unclear. In addition, the nature of the cofactor remains a controversy. Here,

Yoo Seong Choi; Houjin Zhang; Joseph S. Brunzelle; Satish K. Nair; Huimin Zhao

2008-01-01

25

Proof of chymotrypsin activity by a peroral test using a synthetic peptide with a C-terminal P-aminobenzoic acid residue.  

PubMed

The reciprocal relationship between the peroral dose and urinary excretion and the optimum testing load of para-aminobenzoic acid (PABA) and N-acetyl tyrosine peptide (Ac-L-Tyr-PABA), alone and after cholecystokinin-pancreozymin and secretin hormonal stimulation, was studied in rats. Between the peroral test dose of PABA and its urinary excretion there is a constant proportionality which is correlated to the size of the dose and is linear in the dose range up to 50 mg/kg b.w. The situation for Ac-L-Tyr-PABA is similar. Dosage of over 50 mg/kg b.w. do not lead to proportional excretion of the test substance in the urine. I.v. stimulation by cholecystokinin-pancreozymin and secretin, using peroral administration of Ac-L-Tyr-PABA, was not followed by a significant increase in urinary PABA excretion. The optimum peroral load of both PABA and Ac-L Tyr-PABA in the rat is 50 mg/kg b.w. With this dose, 82% of free PABA and 77% of the model peptide PABA excreted in 24 hours is found in the urine after 6 hours, so that for practical purposes this interval is adequate. The findings furnish important information on the possibilities of utilizing the given technique for diagnosing the state of exocrine pancreatic function in clinical practice. PMID:307905

Malis, F; Fric, P; Kasafrek, E; Korbov, L; Kohout, J

1977-01-01

26

In vitro reconstitution and crystal structure of p-aminobenzoate N-oxygenase (AurF) involved in aureothin biosynthesis.  

PubMed

p-Aminobenzoate N-oxygenase (AurF) from Streptomyces thioluteus catalyzes the formation of unusual polyketide synthase starter unit p-nitrobenzoic acid (pNBA) from p-aminobenzoic acid (pABA) in the biosynthesis of antibiotic aureothin. AurF is a metalloenzyme, but its native enzymatic activity has not been demonstrated in vitro, and its catalytic mechanism is unclear. In addition, the nature of the cofactor remains a controversy. Here, we report the in vitro reconstitution of the AurF enzyme activity, the crystal structure of AurF in the oxidized state, and the cocrystal structure of AurF with its product pNBA. Our combined biochemical and structural analysis unequivocally indicates that AurF is a non-heme di-iron monooxygenase that catalyzes sequential oxidation of aminoarenes to nitroarenes via hydroxylamine and nitroso intermediates. PMID:18458342

Choi, Yoo Seong; Zhang, Houjin; Brunzelle, Joseph S; Nair, Satish K; Zhao, Huimin

2008-05-05

27

In vitro reconstitution and crystal structure of p-aminobenzoate N-oxygenase (AurF) involved in aureothin biosynthesis  

PubMed Central

p-aminobenzoate N-oxygenase (AurF) from Streptomyces thioluteus catalyzes the formation of unusual polyketide synthase starter unit p-nitrobenzoic acid (pNBA) from p-aminobenzoic acid (pABA) in the biosynthesis of antibiotic aureothin. AurF is a metalloenzyme, but its native enzymatic activity has not been demonstrated in vitro, and its catalytic mechanism is unclear. In addition, the nature of the cofactor remains a controversy. Here, we report the in vitro reconstitution of the AurF enzyme activity, the crystal structure of AurF in the oxidized state, and the cocrystal structure of AurF with its product pNBA. Our combined biochemical and structural analysis unequivocally indicates that AurF is a non-heme di-iron monooxygenase that catalyzes sequential oxidation of aminoarenes to nitroarenes via hydroxylamine and nitroso intermediates.

Choi, Yoo Seong; Zhang, Houjin; Brunzelle, Joseph S.; Nair, Satish K.; Zhao, Huimin

2008-01-01

28

The Folate Precursor p-Aminobenzoate Is Reversibly Converted to Its Glucose Ester in the Plant Cytosol  

Microsoft Academic Search

Plants synthesize p-aminobenzoate (pABA) in chloro- plasts and use it for folate synthesis in mitochondria. It has generally been supposed that pABA exists as the free acid in plant cells and that it moves between or- ganelles in this form. Here we show that fruits and leaves of tomato and leaves of a diverse range of other plants have a

Eoin P. Quinlivan; Sanja Roje; Gilles Basset; Yair Shachar-Hill; Jesse F. Gregory III; Andrew D. Hanson

2003-01-01

29

Nucleotide sequence of Escherichia coli pabB indicates a common evolutionary origin of p-aminobenzoate synthetase and anthranilate synthetase.  

PubMed Central

Biochemical and immunological experiments have suggested that the Escherichia coli enzyme p-aminobenzoate synthetase and anthranilate synthetase are structurally related. Both enzymes are composed of two nonidentical subunits. Anthranilate synthetase is composed of proteins encoded by the genes trp(G)D and trpE, whereas p-aminobenzoate synthetase is composed of proteins encoded by pabA and pabB. These two enzymes catalyze similar reactions and produce similar products. The nucleotide sequences of pabA and trp(G)D have been determined and indicate a common evolutionary origin of these two genes. Here we present the nucleotide sequence of pabB and compare it with that of trpE. Similarities are 26% at the amino acid level and 40% at the nucleotide level. We propose that pabB and trpE arose from a common ancestor and hence that there is a common ancestry of genes encoding p-aminobenzoate synthetase and anthranilate synthetase.

Goncharoff, P; Nichols, B P

1984-01-01

30

FOLATE SYNTHESIS IN PLANTS: THE LAST STEP OF THE P-AMINOBENZOATE BRANCH IS CATALYZED BY A PLASTIDIAL AMINODEOXYCHORISMATE LYASE  

Technology Transfer Automated Retrieval System (TEKTRAN)

In plants, the last step in the synthesis of the p-aminobenzoate (PABA) moiety of folate remains to be elucidated. In Escherichia coli, this step is catalyzed by the PabC protein, a b-lyase that converts 4-amino-4-deoxychorismate (ADC) - the reaction product of the PabA and PabB enzymes - to PABA an...

31

TiO2 nanowire FET device: encapsulation of biomolecules by electro polymerized pyrrole propylic acid.  

PubMed

Silane-based methods have become the standards for the conjugation of biomolecules, especially for the preparation of one-dimensional nanomaterial biosensors. However, the specific binding of those target molecules might raise problems with regard to the sensing and non-sensing regions, which may contaminate the sensing devices and decrease their sensitivity. This paper attempts to explore the encapsulation of biomolecules on a one-dimensional nanomaterial field effect transistor (FET) biosensor using polypyrrole propylic acid (PPa). Specifically, the encapsulation of biomolecules via the electropolymerization of pyrrole propylic acid (Pa), a self-made low-conductivity polymer, on TiO(2)-nanowire (NW)-based FETs is presented. The energy dispersive spectrum (EDS) was obtained and electrical analysis was conducted to investigate PPa entrapping anti-rabbit IgG (PPa/1Ab) on a composite film. The specificity, selectivity and sensitivity of the sensor were analyzed in order to determine the immunoreaction of PPa/1Ab immobilized NW biosensors. Our results show that PPa/1Ab achieved high specificity immobilization on NWs under the EDS analysis. Furthermore, the TiO(2)-NW FET immunosensor developed in this work successfully achieved specificity, selectivity and sensitivity detection for the target protein rabbit IgG at the nano-gram level. The combination of PPa material and the electropolymerization method may provide an alternative method to immobilize biomolecules on a specific surface, such as NWs. PMID:21036030

Chu, Yung-Ming; Lin, Chi-Chang; Chang, Hsien-Chang; Li, Changming; Guo, Chunxian

2010-10-14

32

Completing the folate biosynthesis pathway in Plasmodium falciparum: p-aminobenzoate is produced by a highly divergent promiscuous aminodeoxychorismate lyase.  

PubMed

Enzymes that produce or recycle folates are the targets of widely used antimalarial drugs. Despite the interest in the folate metabolism of Plasmodium falciparum, the molecular identification of ADCL (aminodeoxychorismate lyase), which synthesizes the p-aminobenzoate moiety of folate, remained unresolved. In the present study, we demonstrate that the plasmodial gene PF14_0557 encodes a functional ADCL and report a characterization of the recombinant enzyme. PMID:23957380

Magnani, Giovanni; Lomazzi, Michela; Peracchi, Alessio

2013-10-15

33

Fabrication of calcium phosphatecalcium sulfate injectable bone substitute using hydroxy-propyl-methyl-cellulose and citric acid  

Microsoft Academic Search

In this study, an injectable bone substitute (IBS) consisting of citric acid, chitosan, and hydroxyl propyl methyl cellulose\\u000a (HPMC) as the liquid phase and tetra calcium phosphate (TTCP), dicalcium phosphate dihydrate (DCPD) and calcium sulfate dehydrate\\u000a (CSD, CaSO42H2O) powders as the solid phase, were fabricated. Two groups were classified based on the percent of citric acid in the liquid\\u000a phase

Van Viet Thai; Byong-Taek Lee

2010-01-01

34

Inhibition of p-aminobenzoate and folate syntheses in plants and apicomplexan parasites by natural product rubreserine.  

PubMed

Glutamine amidotransferase/aminodeoxychorismate synthase (GAT-ADCS) is a bifunctional enzyme involved in the synthesis of p-aminobenzoate, a central component part of folate cofactors. GAT-ADCS is found in eukaryotic organisms autonomous for folate biosynthesis, such as plants or parasites of the phylum Apicomplexa. Based on an automated screening to search for new inhibitors of folate biosynthesis, we found that rubreserine was able to inhibit the glutamine amidotransferase activity of the plant GAT-ADCS with an apparent IC(50) of about 8 ?M. The growth rates of Arabidopsis thaliana, Toxoplasma gondii, and Plasmodium falciparum were inhibited by rubreserine with respective IC(50) values of 65, 20, and 1 ?M. The correlation between folate biosynthesis and growth inhibition was studied with Arabidopsis and Toxoplasma. In both organisms, the folate content was decreased by 40-50% in the presence of rubreserine. In both organisms, the addition of p-aminobenzoate or 5-formyltetrahydrofolate in the external medium restored the growth for inhibitor concentrations up to the IC(50) value, indicating that, within this range of concentrations, rubreserine was specific for folate biosynthesis. Rubreserine appeared to be more efficient than sulfonamides, antifolate drugs known to inhibit the invasion and proliferation of T. gondii in human fibroblasts. Altogether, these results validate the use of the bifunctional GAT-ADCS as an efficient drug target in eukaryotic cells and indicate that the chemical structure of rubreserine presents interesting anti-parasitic (toxoplasmosis, malaria) potential. PMID:22577137

Camara, Djeneb; Bisanz, Cordelia; Barette, Caroline; Van Daele, Jeroen; Human, Esmare; Barnard, Bernice; Van der Straeten, Dominique; Stove, Christophe P; Lambert, Willy E; Douce, Roland; Marchal, Eric; Birkholtz, Lyn-Marie; Cesbron-Delauw, Marie-France; Dumas, Renaud; Rbeill, Fabrice

2012-05-10

35

Propyl gallate synthesis using acidophilic tannase and simultaneous production of tannase and gallic acid by marine Aspergillus awamori BTMFW032.  

PubMed

Marine Aspergillus awamori BTMFW032, recently reported by us, produce acidophilic tannase as extracellular enzyme. Here, we report the application of this enzyme for synthesis of propyl gallate by direct transesterification of tannic acid and in tea cream solubilisation besides the simultaneous production of gallic acid along with tannase under submerged fermentation by this fungus. This acidophilic tannase enabled synthesis of propyl gallate by direct transesterification of tannic acid using propanol as organic reaction media under low water conditions. The identity of the product was confirmed with thin layer chromatography and Fourier transform infrared spectroscopy. It was noted that 699U/ml of enzyme could give 60% solubilisation of tea cream within 1h. Enzyme production medium was optimized adopting Box-Behnken design for simultaneous synthesis of tannase and gallic acid. Process variables including tannic acid, sodium chloride, ferrous sulphate, dipotassium hydrogen phosphate, incubation period and agitation were recognized as the critical factors that influenced tannase and gallic acid production. The model obtained predicted 4,824.61U/ml of tannase and 136.206?g/ml gallic acid after 48h of incubation, whereas optimized medium supported 5,085U/ml tannase and 372.6?g/ml of gallic acid production after 36 and 84h of incubation, respectively, with a 15-fold increase in both enzyme and gallic acid production. Results indicated scope for utilization of this acidophilic tannase for transesterification of tannic acid into propyl gallate, tea cream solubilisation and simultaneous production of gallic acid along with tannase. PMID:21279470

Beena, P S; Basheer, Soorej M; Bhat, Sarita G; Bahkali, Ali H; Chandrasekaran, M

2011-01-29

36

21 CFR 184.1660 - Propyl gallate.  

Code of Federal Regulations, 2010 CFR

... ). Natural occurrence of propyl gallate has not been reported. It is commercially prepared by esterification of gallic acid with propyl alcohol followed by distillation to remove excess alcohol. (b) The ingredient meets the...

2009-04-01

37

21 CFR 184.1660 - Propyl gallate.  

Code of Federal Regulations, 2010 CFR

... ). Natural occurrence of propyl gallate has not been reported. It is commercially prepared by esterification of gallic acid with propyl alcohol followed by distillation to remove excess alcohol. (b) The ingredient meets the...

2010-01-01

38

FOLATE SYNTHESIS IN PLANTS: THE P-AMINOBENZOATE BRANCH IS INITIATED BY A BIFUNCTIONAL PABA-PABB PROTEIN THAT IS TARGETED TO PLASTIDS  

Technology Transfer Automated Retrieval System (TEKTRAN)

It is not known how plants synthesize the p-aminobenzoate (pABA) moiety of folates. In Escherichia coli, pABA is made from chorismate in two steps. First, the PabA and PabB proteins interact to catalyze transfer of the amide nitrogen of glutamine to chorismate, forming aminodeoxychorismate (ADC). Th...

39

Fabrication of calcium phosphate-calcium sulfate injectable bone substitute using hydroxy-propyl-methyl-cellulose and citric acid  

PubMed Central

In this study, an injectable bone substitute (IBS) consisting of citric acid, chitosan, and hydroxyl propyl methyl cellulose (HPMC) as the liquid phase and tetra calcium phosphate (TTCP), dicalcium phosphate dihydrate (DCPD) and calcium sulfate dehydrate (CSD, CaSO42H2O) powders as the solid phase, were fabricated. Two groups were classified based on the percent of citric acid in the liquid phase (20, 40 wt%). In each groups, the HPMC percentage was 0, 2, and 4 wt%. An increase in compressive strength due to changes in morphology was confirmed by scanning electron microscopy images. A good conversion rate of HAp at 20% citric acid was observed in the XRD profiles. In addition, HPMC was not obviously affected by apatite formation. However, both HPMC and citric acid increased the compressive strength of IBS. The maximum compressive strength for IBS was with 40% citric acid and 4% HPMC after 14days of incubation in 100% humidity at 37C.

Thai, Van Viet

2010-01-01

40

Gallic acid, a metabolite of the antioxidant propyl gallate, inhibits gap junctional intercellular communication via phosphorylation of connexin 43 and extracellular-signal-regulated kinase1\\/2 in rat liver epithelial cells  

Microsoft Academic Search

Propyl gallate and its metabolite, gallic acid, are widely used as antioxidants in the food industry, but they have been shown to exhibit liver toxicity and enhance carcinogenesis. In the present study, we investigated the possible undesirable effects of propyl gallate and gallic acid on gap junctional intercellular communication (GJIC), inhibition of which is closely linked to carcinogenesis. Gallic acid

Jong Hun Kim; Nam Joo Kang; Bo Kyung Lee; Ki Won Lee; Hyong Joo Lee

2008-01-01

41

Silica-bonded N-propyl sulfamic acid used as a heterogeneous catalyst for transesterification of soybean oil with methanol.  

PubMed

The transesterification of soybean oil with methanol was carried out, to produce biodiesel, over silica-bonded N-propyl sulfamic acid in a heterogeneous manner. Results showed that a maximum conversion of 90.5% was achieved using a 1:20 M ratio of soybean oil to methanol and a catalyst amount of 7.5 wt.% at 423 K for 60 h. It was found that the free fatty acid (FFA) and water present in the feedstock had no significant influence on the catalytic activity to the transesterification reaction. Besides, the catalyst also showed activities towards the esterification reaction of FFAs, in terms of the FFA conversion of 95.6% at 423 K for 30 h. Furthermore, the catalyst could be recovered with a better reusability. PMID:21871795

Xie, Wenlei; Yang, Dong

2011-08-09

42

Fabrication of calcium phosphate-calcium sulfate injectable bone substitute using hydroxy-propyl-methyl-cellulose and citric acid.  

PubMed

In this study, an injectable bone substitute (IBS) consisting of citric acid, chitosan, and hydroxyl propyl methyl cellulose (HPMC) as the liquid phase and tetra calcium phosphate (TTCP), dicalcium phosphate dihydrate (DCPD) and calcium sulfate dehydrate (CSD, CaSO4 x 2H2O) powders as the solid phase, were fabricated. Two groups were classified based on the percent of citric acid in the liquid phase (20, 40 wt%). In each groups, the HPMC percentage was 0, 2, and 4 wt%. An increase in compressive strength due to changes in morphology was confirmed by scanning electron microscopy images. A good conversion rate of HAp at 20% citric acid was observed in the XRD profiles. In addition, HPMC was not obviously affected by apatite formation. However, both HPMC and citric acid increased the compressive strength of IBS. The maximum compressive strength for IBS was with 40% citric acid and 4% HPMC after 14 days of incubation in 100% humidity at 37 degrees C. PMID:20333539

Thai, Van Viet; Lee, Byong-Taek

2010-03-24

43

Silica-bonded N-propyl sulfamic acid as an efficient catalyst for the formylation and acetylation of alcohols and amines under heterogeneous conditions  

Microsoft Academic Search

A simple and efficient procedure for the preparation of silica-bonded N-propyl sulfamic acid (SBNPSA) by the reaction of 3-aminopropylsilica (1) and chlorosulfonic acid in chloroform is described. This solid acid is employed as a new catalyst for the formylation of alcohols and amines with ethyl formate under mild and heterogeneous conditions at room temperature with good to excellent yields. Also,

Khodabakhsh Niknam; Dariush Saberi

2009-01-01

44

Linkage and branch analysis of high-mannose oligosaccharides using closed-ring labeling of 8-aminopyrene-1,3,6-trisulfonate and p-aminobenzoic ethyl ester and negative ion trap mass spectrometry.  

PubMed

A strategy based on negative ion electrospray ionization tandem mass spectrometry and closed-ring labeling with both 8-aminopyrene-1,3,6-trisulfonate (APTS) and p-aminobenzoic acid ethyl ester (ABEE) was developed for linkage and branch determination of high-mannose oligosaccharides. X-type cross-ring fragment ions obtained from APTS-labeled oligosaccharides by charge remote fragmentation provided information on linkages near the non-reducing terminus. In contrast, A-type cross-ring fragment ions observed from ABEE-labeled oligosaccharides yielded information on linkages near the reducing terminus. This complementary information provided by APTS- and ABEE-labeled oligosaccharides was utilized to delineate the structures of the high-mannose oligosaccharides. As a demonstration of this approach, the linkages and branches of high-mannose oligosaccharides Man(5)GlcNAc(2), Man(6)GlcNAc(2), Man(8)GlcNAc(2), and Man(9)GlcNAc(2) cleaved from the ribonuclease B were assigned from MS(2) spectra of ABEE- and APTS-labeled derivatives. PMID:22673837

Chen, Shu-Ting; Her, Guor-Rong

2012-06-07

45

Corrosion inhibition efficiency of nonionic Schiff base amphiphiles of p-aminobenzoic acid for aluminum in 4N HCL  

Microsoft Academic Search

A novel series of self-assembled nonionic Schiff base amphiphiles was synthesized and their chemical structures were confirmed using elemental analysis, FTIR spectroscopy and 1H NMR spectra. The surface activities of these amphiphiles were determined based on the data of surface and interfacial tension, critical micelle concentration, effectiveness, efficiency, maximum surface excess and minimum surface area. Thermodynamics of adsorption and micellization

Nabel A. Negm; Mohamed F. Zaki

2008-01-01

46

Metal-mediated oxidative damage to cellular and isolated DNA by gallic acid, a metabolite of antioxidant propyl gallate  

Microsoft Academic Search

Propyl gallate (PG), widely used as an antioxidant in foods, is carcinogenic to mice and rats. PG increased the amount of 8-oxo-7,8-dihydro-2?-deoxyguanosine (8-oxodG), a characteristic oxidative DNA lesion, in human leukemia cell line HL-60, but not in HP100, which is hydrogen peroxide (H2O2)-resistant cell line derived from HL-60. Although PG induced no or little damage to 32P-5?-end-labeled DNA fragments obtained

Hatasu Kobayashi; Shinji Oikawa; Kazutaka Hirakawa; Shosuke Kawanishi

2004-01-01

47

Blockade of human neutrophil activation by 2-[2-propyl-3-[3-[2-ethyl-4-(4-fluorophenyl)-5-hydroxyphenoxy]propoxy]phenoxy]benzoic acid (LY293111), a novel leukotriene B 4 receptor antagonist  

Microsoft Academic Search

Leukotriene B4 (LTB4), a naturally occurring pro-inflammatory product of arachidonic acid metabolism, has been associated with human inflammatory disease. This study compares the abilities of two LTB4 receptor antagonists, 2-[2-propyl-3-[3-[2-ethyl-4-(4-fluorophenyl)-5-hydroxyphenoxy]-propoxy]phenoxy]benzoic acid (LY293111) and 7-[3-(4-acetyl-3-methoxy-2-propylphenoxy)-propoxy]-3, 4-dihydro-8-propyl-2H-1-benzopyran-2-carboxylic acid (SC-41930), to displace LTB4 binding and their functional blockade of human neutrophil activation. LY293111 inhibited the binding of [3H]LTB4 with a Ki, of 25

Philip Marder; J. Scott Sawyer; Larry L. Froelich; Larry L. Mann; Stephen M. Spaethe

1995-01-01

48

Laser mass-resolved spectroscopy and theoretical study of methyl-p-aminobenzoate(H2O)n (n=2,3,4) complexes  

NASA Astrophysics Data System (ADS)

A combined computational and experimental study of the methyl-p-aminobenzoate(H2O)n, (n=2,3,4) complexes [MAB(H2O)n] is reported. Complexes potential energy surfaces were explored by ab initio density functional theory (DFT) methods, at the B3LYP/6-31G level, and the stable isomer structures and vibrational modes further computed at the B3LYP/6-31+G* level. A set of self-contained experimental techniques, including laser induced fluorescence (LIF), resonance enhanced multiphoton ionization mass-resolved spectroscopy (REMPI), two-color resonance enhanced multiphoton ionization mass-resolved spectroscopy (R2PI), ``hole burning'' spectroscopy (HB), and two-color ionization thresholds were used to study the spectra and other physical features of the complexes. Of the three title complexes only MAB(H2O)4 has been observed with our experimental methods, while the MAB(H2O)3 was formed by evaporation and MAB(H2O)2 was not detected at all. It has been shown that the observed MAB(H2O)4 complex has only one isomer with a hydrogen bonded water ring structure attached to the amino hydrogens and its low vibrational modes (up to 165 cm-1) have been assigned. A discussion of the results, including structures of stable isomers, isomer energies, ionization thresholds, and the difficulties in observing some solvated complexes is presented.

Fernndez, Jos A.; Longarte, Asier; Unamuno, Iigo; Castao, Fernando

2000-10-01

49

Amino acid analysis in physiological samples by GC-MS with propyl chloroformate derivatization and iTRAQ-LC-MS/MS.  

PubMed

Two mass spectrometry-based methods for the quantitative analysis of free amino acids are described. The first method uses propyl chloroformate/propanol derivatization and gas chromatography-quadrupole mass spectrometry (GC-qMS) analysis in single-ion monitoring mode. Derivatization is carried out directly in aqueous samples, thereby allowing automation of the entire procedure, including addition of reagents, extraction, and injection into the GC-MS. The method delivers the quantification of 26 amino acids. The isobaric tagging for relative and absolute quantification (iTRAQ) method employs the labeling of amino acids with isobaric iTRAQ tags. The tags contain two different cleavable reporter ions, one for the sample and one for the standard, which are detected by fragmentation in a tandem mass spectrometer. Reversed-phase liquid chromatography of the labeled amino acids is performed prior to mass spectrometric analysis to separate isobaric amino acids. The commercial iTRAQ kit allows for the analysis of 42 physiological amino acids with a respective isotope-labeled standard for each of these 42 amino acids. PMID:22125145

Dettmer, Katja; Stevens, Axel P; Fagerer, Stephan R; Kaspar, Hannelore; Oefner, Peter J

2012-01-01

50

FT-IR SOLUTION SPECTRA OF PROPYL SULFIDE, PROPYL SULFOXIDE, AND PROPYL SULFONE  

EPA Science Inventory

FT-IR spectra were obtained of 0.5% volumetric solutions of propyl sulfide, propyl sulfoxide, and propyl sulfone in hexane, CCl4, CS2, and CHCl3 to assist in the assignment of FT-IR-PAS spectra of propyl sulfoxide sorbed within the structure of several peats and onto cellulose. T...

51

Final Report On the Safety Assessment of Glycolic Acid, Ammonium, Calcium, Potassium, and Sodium Glycolates, Methyl, Ethyl, Propyl, and Butyl Glycolates, and Lactic Acid, Ammonium, Calcium, Potassium, Sodium, and Tea-Lactates, Methyl, Ethyl, Isopropyl, and Butyl Lactates, and Lauryl, Myristyl, and Cetyl Lactates  

Microsoft Academic Search

This report provides a review of the safety of Glycolic Acid, Ammonium, Calcium, Potassium, and Sodium Glycolates, Methyl, Ethyl, Propyl, and Butyl Glycolates, Lactic Acid, Ammonium, Calcium, Potassium, Sodium, and TEA-Lactates, and Lauryl, Myristyl, and Cetyl Lactates. These ingredients belong to a group known as alpha-hydroxy acids (AHAs). Products containing these ingredients may be for consumer use, salon use, or

F. A. Andersen

1998-01-01

52

The efficacy of protective effects of tannic acid, gallic acid, ellagic acid, and propyl gallate against hydrogen peroxide-induced oxidative stress and DNA damages in IMR-90 cells.  

PubMed

There is increasing evidence that reactive oxygen species (ROS) are intimately involved in the oxidative damage of tissues for a wide variety of pulmonary diseases. Thus, it is desirable to search for chemopreventive agents that can counteract ROS-mediated injury to the pulmonary tissues. Using a human lung fibroblast IMR-90 cells as the experimental model, we first demonstrated that nearly 90% of intracellular ROS could be removed when H(2)O(2)-treated cells (200 microM) simultaneously incubated with 10 microg/mL of tannic acid (TA), gallic acid (GA), ellagic acid (EA), and propyl gallate (PA). Using C(11)-BODIPY(581/591 )as a lipid peroxidation probe, we also attested that all these compounds examined (10 microg/mL) could alleviate H(2)O(2)-evoked lipid peroxidation phenomena. Next, we examined the protective effects of these compounds on the depletion of intracellular glutathione (iGSH) in H(2)O(2)-treated cells using CMF-DA probe. Interestingly, PA was demonstrated to be the only compound that could effectively protect the integrity of iGSH from being depleted by this system. Finally, the protective effects of these compounds against oxidative DNA damage were evaluated using 8-oxoguanine formation as a marker. Our data indicated that all four compounds suppressed the formation of 8-oxoguanine effectively. Taken together, our data suggested that TA, GA, EA, and PA can protect cells from oxidative stress. PMID:17628875

Chen, Ching-Hsein; Liu, Tsan-Zon; Chen, Chin-Hui; Wong, Chung Hang; Chen, Chi-Hung; Lu, Fung-Jou; Chen, Ssu Ching

2007-08-01

53

Conversion of nitrogen dioxide, nitric acid, and n-propyl nitrate to nitric oxide by gold-catalyzed reduction with carbon monoxide  

Microsoft Academic Search

A new technique is described for the real-time, quantitative conversion of several XNO compounds to NO, where X denotes a radical group. The technique utilizes the reduction of these compounds by CO at heated gold catalyst to yield NO. The NO product was detected by a sensitive chemiluminescence detector. The technique was demonstrated to convert NO, HNO, and n-propyl nitrate

Mark J. Bollinger; Robert E. Sievers; David W. Fahey; Frederick C. Fehsenfeld

1983-01-01

54

Influence of 4-amino-5-mercapto-3n-propyl-1-2-4-triazole on the corrosion and permeation of hydrogen through mild steel in acidic solutions  

Microsoft Academic Search

The influence of 4-amino-5-mercapto-3 n-propyl-1-2-4-triazole (AMPT) on corrosion and hydrogen permeation through mild steel in 0.5M H2SO4 and 1M HCl has been studied using weight loss measurements and various electrochemical techniques. AMPT is found to be more inhibitive in H2SO4 than in HCl. Potentiodynamic polarisation studies clearly prove the fact that this compound behaves as a mixed inhibitor; but predominantly

M. A. Quraishi; S. Muralidharan; S. V. K. Iyer

2000-01-01

55

Production of n-Propyl Acetate by Reactive Distillation  

Microsoft Academic Search

First steps of the development of a catalytic reactive distillation process for the production of n-propyl acetate based on experiments and simulations are proposed. The kinetics for homogeneously (sulphuric acid) and heterogeneously (Amberlyst 15) catalysed reaction were investigated and the constants for a pseudo-homogeneous model are presented. Pilot plant experiments were performed using a homogeneous strong acid catalyst in a

M. Brehelin; F. Forner; D. Rouzineau; J.-U. Repke; X. Meyer; M. Meyer; G. Wozny

2007-01-01

56

para-aminobenzoic acid used as a marker for completeness of 24 hour urine: assessment of control limits for a specific HPLC method  

Microsoft Academic Search

Objective and design: The study comprised three protocols. Protocol 1 compared a HPLC method with the commonly employed colorimetric diazocoupling method. Protocol 2 examined, if the last dosage of p-aminobenzoic acid (PABA) could be advanced in the old to allow for a delayed age-dependent urinary excretion of PABA. Protocol 3 established limits for recovery of PABA in 24 h urine

J Jakobsen; L Ovesen; S Fagt; AN Pedersen

1997-01-01

57

Cytotoxicity of propyl gallate and related compounds in rat hepatocytes  

Microsoft Academic Search

The cytotoxic effects of propyl gallate (PG), its related gallates and gallic acid have been studied in freshly isolated rat\\u000a hepatocytes. Addition of PG (0.52.0 mM) to hepatocyte suspension elicited concentration-dependent cell death accompanied\\u000a by losses of intracellular ATP, adenine nucleotide pools, glutathione (GSH) and protein thiols. The rapid loss of intracellular\\u000a ATP preceded the onset of cell death caused

Y. Nakagawa; S. Tayama

1995-01-01

58

Safety assessment of propyl paraben: a review of the published literature  

Microsoft Academic Search

Propyl paraben (CAS no. 94-13-3) is a stable, non-volatile compound used as an antimicrobial preservative in foods, drugs and cosmetics for over 50 years. It is an ester of p-hydroxybenzoate. Propyl paraben is readily absorbed via the gastrointestinal tract and dermis. It is hydrolyzed to p-hydroxybenzoic acid, conjugated and the conjugates are rapidly excreted in the urine. There is no

M. G. Soni; G. A. Burdock; S. L. Taylor; N. A. Greenberg

2001-01-01

59

Synthesis of an indole analog of folic acid  

SciTech Connect

The authors study the replacement of the p-aminobenzoic acid (PABA) moiety. The authors synthesized an indole analog of folic acid, namely dimethyl N-(5-(2'-amino-4'-oxo-6'-pteridinyl)methylaminoindol-2-yl)glutamate. The physicochemical properties and the chemical shifts in the PMR spectra of the compounds obtained are shown. The examination of the compound for antitumor activity was carried out using rats and mice.

Shengeliya, M.S.; Avramenko, V.G.; Kuleshova, L.N.; Ershova, Yu.A.; Chernov, V.A.; Surorov, N.N.

1987-06-01

60

Selective inhibitory actions of sodium-p-benzyl-4-[1-oxo-2-(4-chlorobenzyl)-3-phenyl propyl] phenyl phosphonate (N-0161) and indomethacin on the biosynthesis of prostaglandins and thromboxanes from arachidonic acid.  

PubMed

1 Sodium p-benzyl-4-[1-oxo-2-(4-chlorobenzyl)-3-phenyl propyl]phenyl phosphonate (N-0164) selectively inhibited the formation of thromboxane-A(2) from prostaglandin endoperoxides by human platelet microsomes in a dose-dependent manner (IC(50) 2.2 x 10(-5) M or 11.6 mug/ml).2 N-0164 was approximately 15 to 20 times as potent as indomethacin as an inhibitor of thromboxane-A(2) formation. In contrast, indomethacin was 20 times as potent as N-0164 as an inhibitor of prostaglandin endoperoxide formation from arachidonic acid (IC(50) 2.6 x 10(-5) M or 9.4 mug/ml).3 Spiral strips of dog coronary arteries relaxed in the presence of prostaglandin endoperoxides and were contracted by prostaglandin E(2) and thromboxane-A(2) and were therefore used to distinguish between prostaglandins and their intermediate precursors, the endoperoxides.4 Neither indomethacin nor N-0164 (both 50 mug/ml) significantly inhibited the formation of prostaglandin-like activity from the endoperoxides following incubation with indomethacin-pretreated rabbit kidney medulla microsomes.5 It is not known whether this action of N-0164 is related to its ability to antagonize certain actions of prostaglandins (and related compounds) or whether N-0164 can penetrate the cell membrane to inhibit thromboxane formation in the intact cell.6 Selective inhibition of thromboxane formation by drugs such as N-0164 may be useful both clinically and as a pharmacological tool to elucidate the patho-physiological roles of the thromboxanes. PMID:884384

Eakins, K E; Kulkarni, P S

1977-05-01

61

21 CFR 582.3660 - Propyl gallate.  

Code of Federal Regulations, 2013 CFR

...3660 Section 582.3660 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT...RECOGNIZED AS SAFE Chemical Preservatives § 582.3660 Propyl gallate...generally recognized as safe for use in food when the total content of...

2013-04-01

62

The local antinociceptive and topical anti-inflammatory effects of propyl gallate in rodents.  

PubMed Central

1 In common with several anti-inflammatory, analgesic, local anaesthetic and antioxidant drugs, propyl gallate in vitro inhibited the biosynthesis of prostaglandin E2 and F2alpha from arachidonic acid by a prostaglandin synthetase from bull seminal vesicles. 2 In common with analgesic drugs, propyl gallate reduced the ability of arachidonic acid, acetylcholine or acetic acid to cause abdominal constriction in mice. 3 Using a new method for evaluating anti-inflammatory activity, we demonstrated the effectiveness of aspirin or indomethacin given subcuteneously before u.v. irradiation of guinea-pig ears, the prophylactic action of topically applied sunscreen agents and the therapeutic value of bufexamac and propyl gallate applied after irradiation.

McDonald-Gibson, W J; Saeed, S A; Schneider, C

1976-01-01

63

Enhancement of propyl gallate yield in nonaqueous medium using novel cell-associated tannase of Bacillus massiliensis.  

PubMed

Enzymatic synthesis of propyl gallate in organic solvent was studied using cell-associated tannase (EC 3.1.1.20) of Bacillus massiliensis. Lyophilized biomass showing tannase activity was used as the biocatalyst. The effects of solvent, surfactant treatment, and bioimprinting on the propyl gallate synthesis were studied and subsequently optimized. Among various solvents, benzene followed by hexane was found to be the most favorable. Treatment of the biocatalyst with Triton X-100 at a lower concentration (0.2% w/v), before lyophilization, increased the propyl gallate yield by 24.5% compared to the untreated biocatalyst. The biocatalyst was imprinted with various concentrations of gallic acid and tannic acid. Biocatalyst imprinted with tannic acid showed 50% enhancement in the propyl gallate yield compared to the non-imprinted biocatalyst. PMID:23581780

Aithal, Mahesh; Belur, Prasanna D

2013-01-01

64

High Performance Liquid Chromatography Determination of Chemical Preservatives in Yogurt  

Microsoft Academic Search

Reverse phase HPLC was used to determine the preservatives methyl-, ethyl- and propyl-p-hydroxybenzoate and sorbic acid in aqueous solutions, using n-butyl-p-aminobenzoate as the internal standard. This method was applied to the analysis of preservatives in yogurt. the preservatives were previously identified by thin layer chromatography, and revealed at 254 nm.

Ftima Olea Serrano; Isabel Snchez Lpez; Gloria Noguera Revilla

1991-01-01

65

GRAS (Generally Recognized as Safe) Food Ingredients: Propyl Gallate.  

National Technical Information Service (NTIS)

The report summarizes the available scientific literature from 1920 to 1972, related to the 'safety' of propyl gallate as a food ingredient. Chemical information, biological data, and biochemical aspects of propyl gallate are given in a 48 page summary co...

1972-01-01

66

Room-temperature luminescence of the volatile compounds, 1- and 2-naphthol, and other compounds, 5,6-benzoquinoline, 4-phenylphenol, phenanthrene, triphenylene, and p-aminobenzoic acid, adsorbed on filter paper treated with salts and cyclodextrins  

SciTech Connect

1- and 2-Naphthol are known to volatilize upon heating along with solvents such as ethanol and water. Filter paper, treated with salts and cyclodextrins, was shown to be capable of trapping these volatile phosphors efficiently on filter paper and permitting strong luminescence signals to be observed. Filter paper samples treated with and without cyclodextrins were compared on the basis of their ability to induce room-temperature fluorescence and phosphorescence from adsorbed naphthols and five other organic compounds. Also, the effect of heavy-atom salt, NaBr, on the phosphorescence intensities of phosphors adsorbed on the filter paper surfaces was studied.

Ramasamy, S.M.; Hurtubise, R.J. (Univ. of Wyoming, Laramie, WY (United States))

1989-01-01

67

Determination of protease-cleaved pA mino b enzoic A cid (PABA) in serum after oral administration of N-benzoyl-L-tyrosyl-p-aminobenzoic acid (PABA-peptide) in children  

Microsoft Academic Search

A modification of the urine PABA test published by Imondi et al. is described. Ninety minutes after oral administration of PABA peptide, PABA was determined in serum. The average concentration in healthy children was 0.420.055 mg per 100 ml. Up to that time we recovered in the urine 66.16.1% of the substance previously administered. In the children with cystic fibrosis

G. Dockter; I. Nacu; E. Kohlberger

1981-01-01

68

Propyl propionate methanolysis kinetics: experiment and modeling.  

PubMed

In concentrated solutions, the reaction rate constant calculated from the law of mass action depends on a mixture composition. In this study, we suggest a new approach based on the dynamic equilibrium principle and modified equations of van Rysselberghe and de Donder. Experimental results obtained for propyl propionate methanolysis are in good agreement with calculated ones in the entire area of studied compositions. Such a method allows one to describe kinetics of reversible chemical reactions on both sides of the equilibrium. PMID:23991713

Povarov, Vladimir G; Keresten, Andrey A

2013-09-17

69

Toxicity of organic acids for repair-deficient strains of Escherichia coli.  

PubMed Central

The wild-type strain and four DNA repair-deficient strains (uvrA6, uvrB5, recA56, and polA1) of Escherichia coli K-12 were treated with acetic acid, lactic acid, and p-aminobenzoic acid at pH 3.5 during their stationary phase of growth. All three acids were highly toxic to the polymerase-deficient strain. The greater sensitivity of the strain carrying the polA1 gene than its isogenic pol+ derivatives suggested that damage caused by acidity requires polA+ gene products for repair.

Sinha, R P

1986-01-01

70

Structure of complexes of germanium tetrachloride with isomeric amino benzoic acids and their derivatives  

Microsoft Academic Search

benzoic acid (GeC14 ?9 40AB), GeC14 ?9 6 0-aminobenzoic acid (GeC14 ?9 60AB), GeC14 . 4 m-aminobenzoic acid (GeC14 ?9 4 MAB), GeC14 ?9 4 p-aminobenzoic acid (GeC14 ?9 4 PAB), and oeC14 ?9 4 anesthesin* (GeC14 . 4 ANS). Their individuality was confirmed by x-ray diffraction, and several properties were determined [10]. The indicated compounds hydrolyzed in water and

E. M. Belousova; I. I. Seifullina; V. N. Reznichenko

1970-01-01

71

Dominant Lethal Assay for Bis-Dinitro-Propyl-Formal: Bis-Dinitro-Propyl-Acetal and Kerimide 601 Resin.  

National Technical Information Service (NTIS)

Bis-dinitro-propyl-formal:bis-dinitro-propyl-acetal (BDNPF:BDNPA) and kerimide 601 resin do not appear to be mutagenic at the doses utilized when introduced intragastrically either as an acute or chronic insult in vivo. It should be pointed out that the d...

J. S. Wilson D. M. Smith

1978-01-01

72

Interaction of single-walled carbon nanotubes with poly(propyl ether imine) dendrimers  

NASA Astrophysics Data System (ADS)

We study the complexation of nontoxic, native poly(propyl ether imine) dendrimers with single-walled carbon nanotubes (SWNTs). The interaction was monitored by measuring the quenching of inherent fluorescence of the dendrimer. The dendrimer-nanotube binding also resulted in the increased electrical resistance of the hole doped SWNT, due to charge-transfer interaction between dendrimer and nanotube. This charge-transfer interaction was further corroborated by observing a shift in frequency of the tangential Raman modes of SWNT. We also report the effect of acidic and neutral pH conditions on the binding affinities. Experimental studies were supplemented by all atom molecular dynamics simulations to provide a microscopic picture of the dendrimer-nanotube complex. The complexation was achieved through charge transfer and hydrophobic interactions, aided by multitude of oxygen, nitrogen, and n-propyl moieties of the dendrimer.

Jayamurugan, G.; Vasu, K. S.; Rajesh, Y. B. R. D.; Kumar, S.; Vasumathi, V.; Maiti, P. K.; Sood, A. K.; Jayaraman, N.

2011-03-01

73

An apparent Bacillus subtilis folic acid biosynthetic operon containing pab, an amphibolic trpG gene, a third gene required for synthesis of para-aminobenzoic acid, and the dihydropteroate synthase gene.  

PubMed Central

McDonald and Burke (J. Bacteriol. 149:391-394, 1982) previously cloned a sulfanilamide-resistance gene, sul, residing on a 4.9-kb segment of Bacillus subtilis chromosomal DNA, into plasmid pUB110. In this study we determined the nucleotide sequence of the entire 4.9-kb fragment. Genes identified on the fragment include pab, trpG, pabC, sul, one complete unidentified open reading frame, and one incomplete unidentified open reading frame. The first three of these genes, pab, trpG, and pabC, are required for synthesis of p-aminobenzoic acid. The trpG gene encodes an amphibolic glutamine amidotransferase required for synthesis of both p-aminobenzoate and anthranilate, the latter an intermediate in the tryptophan biosynthetic pathway. The pabC gene may encode a B. subtilis analog of enzyme X, an enzyme needed for p-aminobenzoate synthesis in Escherichia coli. The sul gene probably encodes dihydropteroate synthase, the enzyme responsible for formation of 7,8-dihydropteroate, the immediate precursor of folic acid. All six of the cloned genes are arranged in a single operon. Since all four of the identified genes are needed for folate biosynthesis, we refer to this operon as a folic acid operon. Expression of the trpG gene is known to be negatively controlled by tryptophan. We propose that this regulation is at the level of translation. This hypothesis is supported by the finding of an apparent Mtr-binding site which overlaps with the trpG ribosome-binding site.

Slock, J; Stahly, D P; Han, C Y; Six, E W; Crawford, I P

1990-01-01

74

Isobaric vapor-liquid equilibria in the binary systems propyl bromide-i-butanol, propyl bromide-1-chlorobutane and 1-chlorobutane-methyl ethyl ketone  

Microsoft Academic Search

Vapor-liquid equilibria at 101.3 kPa have been determined for binary systems propyl bromide-i-butanol, propyl bromide-1-chlorobutane and 1-chlorobutane-methyl ethyl ketone. The binary systems propyl bromide-i-butanol and 1-chlorobutane-methyl ethyl ketone exhibit positive deviations from ideal behavior while the binary system propyl bromide-1-chlorobutane behaves ideally. The activity coefficients and boiling point of the solution were correlated with its composition by the Redlich-Kister and

Jaime Wisniak

1995-01-01

75

Synthesis and properties of new soluble poly(amideimideimide)s based on tetraimide-dicarboxylic acid condensed from ODPA, BAPP and pABA, and various aromatic diamines  

Microsoft Academic Search

A new-type of tetraimide-dicarboxylic acid (I) was synthesized starting from ring-opening addition of p-aminobenzoic acid (p-ABA), 4,4?-oxydiphthalic anhydride (ODPA) and 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) at a 2:2:1 molar ratio in N-methyl-2-pyrrolidone (NMP), followed by cyclodehydration to the diacid I. A series of poly(amideimideimide)s (IIIai) with inherent viscosities of 0.821.20dlg?1 was prepared by triphenyl phosphite-activated polycondensation from the tetraimide-diacid (I) with various aromatic

Chin-Ping Yang; Ruei-Shin Chen; Chi-Shu Wei

2003-01-01

76

Dextran Carrier Macromolecules for Colon-specific Delivery of 5-Aminosalicylic Acid  

PubMed Central

Present manuscript describes the sustained and targeted delivery of 5-aminosalicylic acid to the distal ileum and proximal colon, using dextran (40 kDa) as a carrier for targeting 5-aminosalicylic acid at the colonic site by attaching p-aminobenzoic acid and benzoic acid as linkers. Prepared conjugate were characterized by UV, HPLC, FT-IR, and 1H NMR. The degree of substitution was estimated by complete hydrolysis of conjugates in borate buffer and in vitro hydrolysis study of conjugates was performed in different biological media. It was observed that 5-aminosalicylic acid alone have produced high incidence of gastric ulcer with high ulcer index whereas lower ulcer index was found for the dextran conjugates of 5-aminosalicylic acid. The release pattern of conjugates in 3% w/v rat caecal content was confirmed the colon specificity of 5-aminosalicylic acid conjugates.

Shrivastava, P. K.; Shrivastava, A.; Sinha, S. K.; Shrivastava, S. K.

2013-01-01

77

Antiulcer activity of the calcium antagonist propyl-methylenedioxyindene--V. Localization of site of action.  

PubMed

1. Propyl-methylenedioxyindene (pr-MDI) is an intracellular calcium antagonist which inhibits cold-restraint stress ulceration at subcardiovascular doses (less than or equal to 30 mg/kg). It also inhibits gastric acid secretion evoked by RX77368 (a stable analog of thyrotropin-releasing hormone, the putative mediator of cold-restraint stress ulcers). 2. The objective of this investigation was to localize the site of the inhibitory effect of pr-MDI on gastric acid secretion stimulated by intracisternal (i.c.) administration of RX77368 (100 ng) in rats. 3. Peripheral administration of pr-MDI (30 mg/kg i.p. or i.v.) inhibited the elevated basal and the RX 77368-induced acid secretion in conscious 2-hr pylorus-ligated rats. This effect was completely blocked in anesthetized (urethane or pentobarbital) acute gastric fistula rats. 4. Intracisternal administration of pr-MDI (0.1-1 mumol) produced a dose-related inhibition of acid secretion in conscious pylorus-ligated rats. However, urethane anesthesia completely blocked the inhibitory effect of i.c.-administered pr-MDI (1 mumol) on RX77368-induced acid secretion. 5. Since previous studies indicate that anesthesia does not inhibit peripheral actions of pr-MDI (e.g. the antiarrhythmic effect), the convergent evidence suggests that the inhibitory effect of pr-MDI on gastric acid secretion is mediated primarily via the central nervous system. PMID:1639231

Stephens, R L; Rahwan, R G

1992-03-01

78

Physico-chemical studies and emulsifying properties of N-propyl-N-methylene phosphonic chitosan.  

PubMed

Chitosan is a modified, natural carbohydrate polymer derived by deacetylation of chitin. Due to the presence of two functional groups can undergo many chemical modifications. In a previous work we described the synthetic strategy and characterization of a novel soluble derivative: N-propyl-N-methylene phosphonic chitosan (PNMPC). In the study of some physicochemical properties, results showed that this modified chitosan aggregates in several steps when the concentration is increased. By addition of NaOH the initially coiled molecules stretch exposing more phosphonic acid groups to neutralization and finally give a cooperative reaction with OH((). PNMPC has emulsifying properties and gives O/W emulsions with quasi-monodisperse small droplets. Emulsions with 0.18% PNMPC and 30:70 o:w ratio exhibited the best emulsifying properties within the test range. This emulsion ratio showed high stability to long time storage and several successive freeze/thaw and heating/cooling cycles. PMID:23399201

Albertengo, Liliana; Farenzena, Sonia; Debbaudt, Adriana; Zuiga, Adriana; Schulz, Pablo; Rodriguez, Maria Susana

2012-11-19

79

Addition of amino acids and dipeptides to fullerene C{sub 60} giving rise to monoadducts  

SciTech Connect

The authors have developed a general method for the direct addition of amino acids and dipeptides of various structures to fullerene C{sub 60}. In all cases the addition involves the amino group. The reaction proceeds when the solutions of fullerene and an amino acid (or dipeptide) are mixed at 50-100 {degrees}C. The fullerene derivatives of the following amino acids and dipeptides have been obtained: glycine, p-aminobenzoic acid, {omega}-aminocaproic acid, L-proline, L-alanine, L-alanyl-Lalanine, D,L-alanyl-D,L-alanine, glycyl-L-valine. The adduct of methyl L-ananinate with C{sub 60} was also prepared.

Romanova, V.S.; Tsyryapkin, V.A.; Vol`pin, M.E. [A.N. Nesmeyanov Institute of Organoelement Compounds, Moscow (Russian Federation)] [and others

1994-12-01

80

Co-adsorption of surfactants and propyl gallate on the hydrophilic oxide surfaces  

NASA Astrophysics Data System (ADS)

Propyl gallate (PG) adsolubilisation in the cationic, anionic and nonionic surfactant micelles formed in the bulk solution and at the silica/solution interface has been investigated. It was found that in the absence of surfactant, propyl gallate does not adsorb on the silica surface from aqueous solution. However, in the presence of hexyltrimethylammonium bromide (CTAB), its uptake by silica significantly increases. Alumina is quite an effective adsorbent for SDS and propyl gallate and does not adsorb nonionic TX-100. The addition of PG promotes adsorption of SDS and TX-100.

Drach, Mateusz; Jab?o?ski, Jerzy; Narkiewicz-Micha?ek, Jolanta; Szymula, Marta

2010-06-01

81

Biodegradation of bis(1-chloro-2-propyl) ether via initial ether scission and subsequent dehalogenation by Rhodococcus sp. strain DTB.  

PubMed

Rhodococcus sp. strain DTB (DSM 44534) grows on bis(1-chloro-2-propyl) ether (DDE) as sole source of carbon and energy. The non-chlorinated diisopropyl ether and bis(1-hydroxy-2-propyl) ether, however, did not serve as substrates. In ether degradation experiments with dense cell suspensions, 1-chloro-2-propanol and chloroacetone were formed, which indicated that scission of the ether bond is the first step while dehalogenation of the chlorinated C(3)-compounds occurs at a later stage of the degradation pathway. Inhibition of ether scission by methimazole suggested that the first step in degradation is catalyzed by a flavin-dependent enzyme activity. The non-chlorinated compounds 1,2-propanediol, hydroxyacetone, lactate, pyruvate, 1-propanol, propanal, and propionate also supported growth, which suggested that the intermediates 1,2-propanediol and hydroxyacetone are converted to pyruvate or to propionate, which can be channeled into the citric acid cycle by a number of routes. Total release of chloride and growth-yield experiments with DDE and non-chlorinated C(3)-compounds suggested complete biodegradation of the chlorinated ether. PMID:12605291

Moreno Horn, Marcus; Garbe, Leif-Alexander; Tressl, Roland; Adrian, Lorenz; Grisch, Helmut

2003-02-21

82

Characterization of a tannase from Emericella nidulans immobilized on ionic and covalent supports for propyl gallate synthesis.  

PubMed

The extracellular tannase from Emericela nidulans was immobilized on different ionic and covalent supports. The derivatives obtained using DEAE-Sepharose and Q-Sepharose were thermally stable from 60 to 75 C, with a half life (t50) >24 h at 80 C at pH 5.0. The glyoxyl-agarose and amino-glyoxyl derivatives showed a thermal stability which was lower than that observed for ionic supports. However, when the stability to pH was considered, the derivatives obtained from covalent supports were more stable than those obtained from ionic supports. DEAE-Sepharose and Q-Sepharose derivatives as well as the free enzyme were stable in 30 and 50 % (v/v) 1-propanol. The CNBr-agarose derivative catalyzed complete tannic acid hydrolysis, whereas the Q-Sepharose derivative catalyzed the transesterification reaction to produce propyl gallate (88 % recovery), which is an important antioxidant. PMID:23242498

Gonalves, Helosa Bressan; Jorge, Joo Atlio; Pessela, Benevides Costa; Lorente, Glria Fernandez; Guisn, Jos Manuel; Guimares, Luis Henrique Souza

2012-12-15

83

Metabolism and cytotoxicity of propyl gallate in isolated rat hepatocytes: effects of a thiol reductant and an esterase inhibitor.  

PubMed

The relationship between the metabolism and the cytotoxic effects of propyl gallate (PG) has been studied in freshly isolated rat hepatocytes. Addition of PG (0.5-2.0 mM) to the hepatocytes elicited concentration-dependent cell death, accompanied by decreases in intracellular ATP, adenine nucleotide pools, glutathione, and protein thiols. The rapid loss of ATP preceded the onset of cell death. PG in the hepatocyte suspensions was converted to gallic acid, 4-O-methyl-gallic acid, and other minor products over time. In addition, PG was converted to a dimer [dipropyl-4,4',5,5',6,6'-hexahydroxydiphenate (PG-dimer)] and ellagic acid via autooxidation. In comparisons of the toxic effects of PG and its metabolites at concentrations of 2 mM, the parent compound PG was the most toxic. Pretreatment of hepatocytes with diazinon (100 microM), an esterase inhibitor, enhanced PG-induced cytotoxicity. This was accompanied by delay of PG loss and inhibition of gallic acid formation. The cytotoxicity of PG was also enhanced by addition of the thiol reductant dithiothreitol (4 mM), although intracellular levels of glutathione and protein thiols were maintained during the incubation period. Dithiothreitol did not affect the hydrolysis of PG to gallic acid by esterases but did delay the conversion of PG and prevented the formation of PG-dimer. In isolated hepatic mitochondria, PG elicited a concentration-dependent increase in the rate of state 4 oxygen consumption, indicating an uncoupling effect. In contrast, PG-dimer inhibited the rate of state 3 oxygen consumption. Based on the respiratory control index, the order of potency for impairment of mitochondria was PG > PG-dimer > gallic acid = 4-O-methyl-gallic acid = ellagic acid - propyl alcohol. These results indicate (a) that PG-induced hepatotoxicity is mediated by the parent compound and not its metabolites, (b) that toxicity is associated with ATP depletion apparently independently of cellular thiol depletion, and (c) that mitochondria may represent critical targets of PG-induced cytotoxicity. PMID:7746268

Nakagawa, Y; Nakajima, K; Tayama, S; Moldus, P

1995-05-01

84

Para-aminosalicylic acid acts as an alternative substrate of folate metabolism in Mycobacterium tuberculosis.  

PubMed

Folate biosynthesis is an established anti-infective target, and the antifolate para-aminosalicylic acid (PAS) was one of the first anti-infectives introduced into clinical practice on the basis of target-based drug discovery. Fifty years later, PAS continues to be used to treat tuberculosis. PAS is assumed to inhibit dihydropteroate synthase (DHPS) in Mycobacterium tuberculosis by mimicking the substrate p-aminobenzoate (PABA). However, we found that sulfonamide inhibitors of DHPS inhibited growth of M. tuberculosis only weakly because of their intracellular metabolism. In contrast, PAS served as a replacement substrate for DHPS. Products of PAS metabolism at this and subsequent steps in folate metabolism inhibited those enzymes, competing with their substrates. PAS is thus a prodrug that blocks growth of M. tuberculosis when its active forms are generated by enzymes in the pathway they poison. PMID:23118010

Chakraborty, Sumit; Gruber, Todd; Barry, Clifton E; Boshoff, Helena I; Rhee, Kyu Y

2012-11-01

85

Production of propyl gallate in nonaqueous medium using cell-associated tannase of Bacillus massiliensis: effect of various parameters and statistical optimization.  

PubMed

Enzymatic synthesis of propyl gallate in an organic solvent was studied using cell-associated tannase (E.C. 3.1.1.20) of Bacillus massiliensis. Lyophilized biomass showing tannase activity was used as a biocatalyst. The influence of buffer pH and strength, water activity, temperature, biocatalyst loading, gallic acid concentration, and 1-propanol concentration was studied by the one-factor-at-a-time method. Subsequently, response surface methodology was applied based on a central composite design to determine the effects of three independent variables (biocatalyst loading, gallic acid concentration, and 1-propanol concentration) and their mutual interactions. A total of 20 experiments were conducted, and a statistical model was developed, which predicted the maximum propyl gallate yield of 20.28 ?g/mL in the reaction mixture comprising 40.4 mg biocatalyst, 0.4 mM gallic acid, and 6.52 % (v/v) 1-propanol in 9.5 mL benzene at 30C. The subsequent verification experiments established the validity of the model. Under optimal conditions, 25% conversion of gallic acid to propyl gallate was achieved on a molar basis. The absence of the need for enzyme purification and subsequent immobilization steps and good conversion efficiency makes this enzyme system an interesting one. Reports on the applications of bacterial whole cell systems for synthetic reactions in organic solvents are scarce, and perhaps this is the first report on bacterial cell-associated tannase-mediated esterification in a nonaqueous medium. PMID:23600575

Aithal, Mahesh; Belur, Prasanna D

86

Bromide and N -acetyl- S -( n -propyl)- l -cysteine in urine from workers exposed to 1-bromopropane solvents from vapor degreasing or adhesive manufacturing  

Microsoft Academic Search

Objectives1-Bromopropane (1-BP) is an alternative for ozone depleting and other solvents; it is used in aerosol products, adhesives,\\u000a and cleaning solvents. There is concern that 1-BP may be a reproductive and neurological toxicant. Mercapturic acid conjugates\\u000a are excreted in urine from 1-BP metabolism involving debromination. The main objectives were to evaluate urinary bromide [Br(?)] and N-acetyl-S-(n-propyl)-l-cysteine (AcPrCys) for assessing 1-BP

Kevin William Hanley; Martin R. Petersen; Kenneth L. Cheever; Lian Luo

2010-01-01

87

Lack of spermatotoxic effects of methyl and ethyl esters of p-hydroxybenzoic acid in rats  

Microsoft Academic Search

Parabens are alkyl esters of p-hydroxybenzoic acid widely used as preservatives in foodstuffs, cosmetics toiletries and pharmaceuticals. These compounds are known to exert a weak estrogenic activity in estrogen receptor assays in vitro. In addition butyl and propyl parabens show uterotrophic activity in vivo. It was previously shown that exposure of post-weaning rats and mice to butyl or propyl parabens

Shinshi Oishi

2004-01-01

88

Stimulation of CoA biosynthesis by P-aminobenzoate and benzoate in cultured rat hepatocytes  

SciTech Connect

The effects of paraminobenzoate (PABA) and benzoate (BA) on CoA metabolism were studied in intact hepatocytes to elucidate the role of CoASH and acetyl-CoA in the regulation of CoA biosynthesis. CoASH and acetyl-CoA inhibit isolated pantothenate kinase, a cytosolic enzyme. PABA is N-acetylated (cytosol), and PABA and BA form acyl-CoA's which add glycine to form hippurates. Primary cultures of rat hepatocytes were incubated 6 h with (/sup 14/C)-pantothenate and radioactivity in CoA determined. PABA and BA stimulated (/sup 14/C)-pantothenate conversion to CoA 13-fold and 6-fold respectively. Glycine reversed stimulation by BA, but only partially reversed that by PABA. PABA decreased the CoASH and acetyl-CoA contents by > 90% and 66%, respectively. These changes were also partially reversed by glycine. In freshly isolated hepatocytes PABA decreased both cytosolic and mitochondrial acetyl-CoA levels. The results suggested that mitochondrial PABA-CoA formation, utilization of acetyl-CoA for PABA acetylation, and activation of pantothenate kinase by decreased cytosolic acetyl-CoA CoASH are involved in stimulation of (/sup 14/C)-pantothenate conversion to CoA by PABA.

Roitman, K.J.; Smith, C.M.

1987-05-01

89

Sulfa drug screening in yeast: fifteen sulfa drugs compete with p-aminobenzoate in Saccharomyces cerevisiae  

Microsoft Academic Search

Sulfa drugs have been used as antimicrobials for decades but resistance is now a problem. For major eukaryotic pathogens, including Plasmodium and Pneumocystis, sulfa drug testing is difficult or impossible. We have shown that the eukaryote yeast can be used as a model for the study of sulfa drugs within certain parameters. Fifteen sulfa drugs inhibited yeast growth in a

Laura A Castelli; Nga P Nguyen; Ian G Macreadie

2001-01-01

90

Antifungal effect of different methyl and propyl paraben mixtures on the treatment of paper biodeterioration  

Microsoft Academic Search

With many important artistic works and documents made of paper, and thus susceptible to biodeterioration by fungi, research is required in an effort to replace toxic chemical products with other more benign ones. In this work the antifungal effect of methyl and propyl paraben mixtures at different concentrations was evaluated. The fungi used in the experiments were a Cladosporium species

Eva Raquel Neves; Stephan Schfer; Alan Phillips; Joo Canejo; Maria Filomena Macedo

2009-01-01

91

Pulse and gamma radiolysis studies of 3-sulfo propyl methacrylate in aqueous solutions  

Microsoft Academic Search

Radiation induced polymerization of 3-sulfo propyl methacrylate (SPMA) in aqueous solution (10wt%) has been studied by steady state and pulse radiolysis techniques. The effect of radiation characteristics such as irradiation dose, dose rate and the presence of crosslinking agent on the gel formation of SPMA monomer has been investigated. In N2 -saturated solution, the gel formation doses for SPMA were

Anjali Panda; Hari Mohan; S. Sabharwal

2001-01-01

92

Studies on the Food Additive Propyl Gallate: Synthesis, Structural Characterization, and Evaluation of the Antioxidant Activity  

ERIC Educational Resources Information Center

|Antioxidants are additives largely used in industry for delaying, retarding, or preventing the development of oxidative deterioration. Propyl gallate (E310) is a phenolic antioxidant extensively used in the food, cosmetics, and pharmaceutical industries. A series of lab experiments have been developed to teach students about the importance and

Garrido, Jorge; Garrido, E. Manuela; Borges, Fernanda

2012-01-01

93

75 FR 50922 - Prohydrojasmon, propyl-3-oxo-2-pentylcyclo-pentylacetate; Temporary Exemption From the...  

Federal Register 2010, 2011, 2012, 2013

...propyl-3-oxo-2-pentylcyclo-pentylacetate, on red apple varieties when applied/used as...plant growth regulator applied to red apple varieties pre-harvest. Any...of a tolerance of PDJ when used on red apple varieties without any...

2010-08-18

94

40 CFR 721.9516 - Siloxanes and silicones, 3-[(2-aminoethyl) amino]propyl Me, di-Me, reaction products with...  

Code of Federal Regulations, 2010 CFR

...2-aminoethyl) amino]propyl Me, di-Me, reaction products with polyethylene-polypropylene...2-aminoethyl) amino]propyl Me, di-Me, reaction products with polyethylene-polypropylene...2-aminoethyl) amino]propyl Me, di-Me, reaction products with...

2009-07-01

95

Mechanism of photooxidation of folic acid sensitized by unconjugated pterins.  

PubMed

Folic acid, or pteroyl-l-glutamic acid (PteGlu), is a precursor of coenzymes involved in the metabolism of nucleotides and amino acids. PteGlu is composed of three moieties: a 6-methylpterin (Mep) residue, a p-aminobenzoic acid (PABA) residue, and a glutamic acid (Glu) residue. Accumulated evidence indicates that photolysis of PteGlu leads to increased risk of several pathologies. Thus, a study of PteGlu photodegradation can have significant ramifications. When an air-equilibrated aqueous solution of PteGlu is exposed to UV-A radiation, the rate of the degradation increases with irradiation time. The mechanism involved in this "auto-photo-catalytic" effect was investigated in aqueous solutions using a variety of tools. Whereas PteGlu is photostable under anaerobic conditions, it is converted into 6-formylpterin (Fop) and p-aminobenzoyl-l-glutamic acid (PABA-Glu) in the presence of oxygen. As the reaction proceeds and enough Fop accumulates in the solution, a photosensitized electron-transfer process starts, where Fop photoinduces the oxidation of PteGlu to Fop, and H(2)O(2) is formed. This process also takes place with other pterins as photosensitizers. The results are discussed with the context of previous mechanisms for processes photosensitized by pterins, and their biological implications are evaluated. PMID:20922252

Dntola, M Laura; Denofrio, M Paula; Zurbano, Beatriz; Gimenez, Carlos S; Ogilby, Peter R; Lorente, Carolina; Thomas, Andrs H

2010-10-05

96

No-carrier-added carbon-11-labeled sn-1,2- and sn-1,3-diacylglycerols by [11C]propyl ketene method.  

PubMed

This article describes the preparation of sn-1,2-[11C]diacylglycerols and sn-1,3-[11C]diacylglycerols by a no-carrier-added reaction based on a labeling method using [1-11C]propyl ketene, which is one of the most potent acylating agents. [1-11C]Propyl ketene was produced by pyrolytic decomposition of [1-11C]butyric acid and was trapped in pyridine containing L-alpha-palmitoyl-lysophosphatidylcholine, producing L-alpha-palmitoyl-2-[1-11C]butyryl-sn-glycero-3-phosphorylcholine. We adopted an enzymatic reaction to remove the phosphorylcholine, in which L-alpha-palmitoyl-2-[1-11C]butyryl-sn-glycero-3-phosphorylcholine was incubated with phospholipase C, hydrolyzing to produce 1-palmitoyl-sn-2-[1-11C]butyrylglycerol. Total synthesis time was about 50 minutes and the specific activity was estimated at 93 GBq/mumol (2.5 Ci/mumol) at end of synthesis. Radiochemical yield was 3.8% based on the trapped 11CO2. sn-1,3-[11C]Diacylglycerol was also synthesized by [1-11C]propyl ketene reaction with 1-palmitoyl-sn-glycerol in a single procedure. The regional brain tissue radioactivities obtained in sn-1,2-[11C]diacylglycerol were higher than those of sn-1,3-[11C]diacylglycerol, and the regional values varied widely. In autoradiography of brain slices from conscious rats, sn-1,2-[11C]diacylglycerol incorporation sites were discretely localized, especially in the amygdala, cerebral cortex, and hippocampus, suggesting that intensive neuronal processing occurred in these areas on the basis of phosphatidylinositol turnover. PMID:1869991

Imahori, Y; Fujii, R; Ueda, S; Ido, T; Nishino, H; Moriyama, Y; Yamamoto, Y L; Nakahashi, H

1991-08-01

97

Inhibitory Effects of Propyl Gallate on Tyrosinase and Its Application in Controlling Pericarp Browning of Harvested Longan Fruits.  

PubMed

Tyrosinase (EC 1.14.18.1), also known as polyphenol oxidase (PPO), is a key enzyme in pigment biosynthesis of organisms. The inhibitory effects of propyl gallate on the activity of mushroom tyrosinase and effects of propyl gallate on pericarp browning of harvested longan fruits in relation to phenolic metabolism were investigated. The results showed that propyl gallate could potently inhibit diphenolase activity of tyrosinase. The inhibitor concentration leading to 50% activity lost (IC50) was determined to be 0.685 mM. Kinetic analyses showed that propyl gallate was a reversible and mixed type inhibitor on this enzyme. The inhibition constants (KIS and KI) were determined to be 2.135 and 0.661 mM, respectively. Furthermore, the results also showed that propyl gallate treatment inhibited activities of PPO and POD in pericarp of harvested longan fruits, and maintained higher contents of total phenol and flavonoid of longan pericarp. Moreover, propyl gallate treatment also delayed the increases of browning index and browning degree in pericarp of harvested longan fruits. Therefore, application of propyl gallate may be a promising method for inhibiting tyrosinase activity, controlling pericarp browning, and extending shelf life of harvested longan fruits. PMID:23427826

Lin, Yi-Fen; Hu, Yong-Hua; Lin, He-Tong; Liu, Xuan; Chen, Yi-Hui; Zhang, Shen; Chen, Qing-Xi

2013-03-01

98

Production of lactic acid by Lactobacillus rhamnosus with vitamin-supplemented soybean hydrolysate.  

PubMed

Batch fermentation studies were performed to evaluate the potentials of a complex nitrogen source, soybean, as an alternative to yeast extract for the economical production of lactic acid by Lactobacillus rhamnosus. An enzyme-hydrolysate of soybean meal, Soytone, with an adequate supplementation of vitamins was found to be highly effective in supporting lactic acid production from glucose and lactose. The effects of seven selected vitamins: d-biotin, pyridoxine, p-aminobenzoic acid, nicotinic acid, thiamine, pantothenic acid, and riboflavin, on cell growth and lactic acid production were investigated to provide the basis for the optimization of vitamin supplementation to minimize the cost. Pantothenic acid was the most required compound while the other six vitamins were also essential for high lactic acid productivity. As a result of the optimization, 15 g/l yeast extract could be successfully replaced with 19.3 g/l Soytone supplemented with the vitamins, resulting in a production of 125 g/l lactic acid from 150 g/l glucose. The volumetric productivity and lactate yield were 2.27 g/l/h and 92%, respectively, which were higher than those with 15 g/l yeast extract. The raw material cost was estimated to be 21.4 cent/kg lactic acid, which was only approximately 41% of that with yeast extract. PMID:10689079

Kwon; Lee; Lee; Keun Chang Y; Chang

2000-02-01

99

Characterization of bioimprinted tannase and its kinetic and thermodynamics properties in synthesis of propyl gallate by transesterification in anhydrous medium.  

PubMed

Tannase has been extensively applied to synthesize gallic acid esters. Bioimprinting technique can evidently enhance transesterification-catalyzing performance of tannase. In order to promote the practical utilization of the modified tannase, a few enzymatic characteristics of the enzyme and its kinetic and thermodynamics properties in synthesis of propyl gallate by transesterification in anhydrous medium have been studied. The investigations of pH and temperature found that the imprinted tannase holds an optimum activity at pH 5.0 and 40 C. On the other hand, the bioimprinting technique has a profound enhancing effect on the adapted tannase in substrate affinity and thermostability. The kinetic and thermodynamic analyses showed that the modified tannase has a longer half-time of 1,710 h at 40 C; the kinetic constants, the activation energy of reversible thermal inactivation, and the activation energy of irreversible thermal inactivation, respectively, are 0.054 mM, 17.35 kJ mol(-1), and 85.54 kJ mol(-1) with tannic acid as a substrate at 40 C; the free energy of Gibbs (?G) and enthalpy (?H) were found to be 97.1 and 82.9 kJ mol(-1) separately under the same conditions. PMID:22711493

Nie, Guangjun; Zheng, Zhiming; Gong, Guohong; Zhao, Genhai; Liu, Yan; Song, Junying; Dai, Jun

2012-06-19

100

RADIATION-INDUCED EXCHANGE OF HYDROGEN CHLORIDE-Cl³⁶ AND PROPYL CHLORIDES  

Microsoft Academic Search

The irradiation of the two propyl chlorides has been studied, both ; alone and admixed with hydrogen chlorideCl³⁶. The principal radiolysis ; product is hydrogen chloride; G\\/sub HCI\\/. , values are 3.38 for n-PrCl and 3.82 ; for i-PrCl. The isotopic exchange reaction is zero order in hydrogen chloride; G\\/; sub excchg\\/ values are 3.32 for n-PrCl and 1.27 for

Rowland E. Johnson; Charles E. Miller

1959-01-01

101

Orientational order parameters of nematogenic trans-4-propyl cyclohexyl-4 (trans-4-alkyl cyclohexyl) benzoates  

Microsoft Academic Search

The refractive indices and densities of three members of trans-4-propyl cyclohexyl-4 (trans-4-alkyl cyclohexyl) benzoates\\u000a are reported as functions of temperature in the nematic and isotropic phases. The principal molecular polarizabilities and\\u000a order parameters (S) have been evaluated using the anisotropic internal field model (Neugebauers approach). Also order parameters have been\\u000a estimated by studying the dipole-dipole splittings in the wide line

Srinivasa; M M M Abdoh; N C Shivaprakash; J Shashi-Dhara Prasad

1982-01-01

102

Investigating the Location of Propyl Gallate at Surfaces and Its Chemical Microenvironment by 1 H NMR  

Microsoft Academic Search

The location and the resulting chemical microenvironment of the antioxidant propyl gallate (PG) was studied in micellar solutions\\u000a using the cationic emulsifier cetyl trimethyl ammonium bromide (CTAB), the anionic emulsifier sodium dodecyl sulphate (SDS)\\u000a and the non-ionic emulsifier Brij 58 (polyoxyethylene-20-cetyl ester). T\\u000a 1 relaxation time of the aromatic protons of PG was investigated in micellar solutions and compared with

Anja Heins; Tobias Sokolowski; Heiko Stckmann; Karin Schwarz

2007-01-01

103

Thermal conversion of 2-propyl iodide on O/Ni(100): Changes in produce distribution with varying oxygen coverages  

SciTech Connect

The oxidation of 2-propyl iodide on oxygen-covered Ni(100) surfaces has been studied with temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), and ion-scattering spectroscopy (ISS). The product distribution was strongly dependent on oxygen preexposure. XP I 3d core-level spectra indicate that the adsorption of 2-propyl iodide below 100 K is molecular, and ISS data strongly suggest preferential bonding to Ni sites, Annealing the 2-propyl iodide adsorbed on O/Ni(100) surfaces between 120 to 200 K generates 2-propyl groups on the nickel sites via dissociation of the C-I bond, the same as on the clean surface. 48 refs., 10 figs.

Gleason, N.R.; Zaera, F. [Univ. of California, Riverside, CA (United States)

1997-07-01

104

Determination of cisapride, its oxidation product, propyl and butyl parabens in pharmaceutical dosage form by reversed-phase liquid chromatography  

Microsoft Academic Search

A simple, rapid and reproducible high-performance liquid chromatography (HPLC) assay for cisapride, its oxidation product (OP), propyl and butyl parabens in a pharmaceutical formulation is described. Chromatography was performed at room temperature by pumping acetonitrile20 mM phosphate buffer pH 7 (50:50, v\\/v) at 1.5 ml min?1 through C8 reversed-phase column. Cisapride, OP, propyl and butyl parabens were detected at 276

J.-E. Belgaied; H. Trabelsi

2003-01-01

105

Antiviral evaluation of octadecyloxyethyl esters of ( S)-3-hydroxy-2-(phosphonomethoxy)propyl nucleosides against herpesviruses and orthopoxviruses  

Microsoft Academic Search

Our previous studies showed that esterification of 9-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]adenine (HPMPA) or 1-(S)-[3-hydroxy-2-(phosphonomethoxy)-propyl]cytosine (HPMPC) with alkoxyalkyl groups such as hexadecyloxypropyl (HDP) or octadecyloxyethyl (ODE) resulted in large increases in antiviral activity and oral bioavailability. The HDP and ODE esters of HPMPA were shown to be active in cells infected with human immunodeficiency virus, type 1 (HIV-1), while HPMPA itself was virtually inactive.

Nadejda Valiaeva; Mark N. Prichard; R. Mark Buller; James R. Beadle; Caroll B. Hartline; Kathy A. Keith; Jill Schriewer; Julissa Trahan; Karl Y. Hostetler

2009-01-01

106

Mathematical evaluation of the amino acid and polyphenol content and antioxidant activities of fruits from different apricot cultivars.  

PubMed

Functional foods are of interest because of their significant effects on human health, which can be connected with the presence of some biologically important compounds. In this study, we carried out complex analysis of 239 apricot cultivars (Prunus armeniaca L.) cultivated in Lednice (climatic area T4), South Moravia, Czech Republic. Almost all previously published studies have focused only on analysis of certain parameters. However, we focused on detection both primary and secondary metabolites in a selection of apricot cultivars with respect to their biological activity. The contents of thirteen biogenic alpha-L-amino acids (arginine, asparagine, isoleucine, lysine, serine, threonine, valine, leucine, phenylalanine, tryptophan, tyrosine, proline and alanine) were determined using ion exchange chromatography with UV-Vis spectrometry detection. Profile of polyphenols, measured as content of ten polyphenols with significant antioxidant properties (gallic acid, procatechinic acid, p-aminobenzoic acid, chlorogenic acid, caffeic acid, vanillin, p-coumaric acid, rutin, ferrulic acid and quercetrin), was determined by high performance liquid chromatography with spectrometric/electrochemical detection. Moreover, content of total phenolics was determined spectrophotometrically using the Folin-Ciocalteu method. Antioxidant activity was determined using five independent spectrophotometric methods: DPPH assay, DMPD method, ABTS method, FRAP and Free Radicals methods. Considering the complexity of the obtained data, they were processed and correlated using bioinformatics techniques (cluster analysis, principal component analysis). The studied apricot cultivars were clustered according to their common biochemical properties, which has not been done before. The observed similarities and differences were discussed. PMID:21886093

Sochor, Jiri; Skutkova, Helena; Babula, Petr; Zitka, Ondrej; Cernei, Natalia; Rop, Otakar; Krska, Boris; Adam, Vojtech; Provaznk, Ivo; Kizek, Rene

2011-09-01

107

Endonucleolytic activity directed towards 8-(2-hydroxy-2-propyl) purines in double-stranded DNA.  

PubMed Central

Photoalkylation of circular covalently closed DNA from phage PM2 with isopropyl alcohol by using a free radical photoinitiator and UV light of lambda greater than 305 nm led to the specific 8-substitution of purine moieties in the DNA, yielding 8-(2-hydroxy-2-propyl)adenine and 8-(2-hydroxy-2-propyl)guanine as the only detectable damage in the DNA. Using this specifically photoalkylated DNA as a substrate, we discovered in extracts of Micrococcus luteus an endonucleolytic activity that is directed towards 8-(2-hydroxy-2-propyl) purines in DNA. The activity is not a combination of a DNA-glycosylase and an apurinic site endonuclease. It is not inhibited by single-stranded DNA, by UV- or gamma-irradiated single-stranded DNA, or by normal or depurinated double-stranded DNA. however, gamma- or UV-(254 nm) irradiated double-stranded DNAs to inhibit the activity, hinting at the possibility of a common type of lesion in these damaged DNAs. Divalent cations are not required for the incising activity, and it is fully active in 1 mM EDTA, whereas caffeine and ATP cause inhibition. Extracts of mutant M. luteus lacking pyrimidine-dimer-directed endonucleases were found to contain the endonucleolytic activity in levels comparable to those present in the wild type. After the incision, we could demonstrate the specific excision of the 8-alkylated purines from the damaged DNA. The special conformational consequences of the 8-alkylation of purines, at the nucleotide level, namely their nonregular syn conformation, suggest that it is the distortion in the DNA that is recognized by the endonuclease.

Livneh, Z; Elad, D; Sperling, J

1979-01-01

108

Platinum(II) complexes incorporating racemic and optically active 1-alkyl-3-phospholenes and 1-propyl-phospholane P-ligands: Synthesis, stereostructure, NMR properties and catalytic activity  

Microsoft Academic Search

Racemic and optically active 1-propyl- and 1-butyl-3-methyl-3-phospholene oxides, as well as 1-propyl-3-methylphospholane oxides were converted after deoxygenation to the corresponding phosphine-borane and phopshine-platinum complexes. Stereostructure of the novel platinum complexes with a propyl group on the phosphorus atom was evaluated by quantum chemical calculations. The complexes displayed characteristic properties regarding their NMR spectra and showed unusual regioselectivity as catalysts in

Gyrgy Keglevich; Pter Bagi; ron Szll?sy; Tams Krtvlyesi; Pter Pongrcz; Lszl Kollr; Lszl Drahos

2011-01-01

109

Bioorganometallic chemistry. 8. The molecular recognition of aromatic and aliphatic amino acids and substituted aromatic and aliphatic carboxylic acid guests with supramolecular ({eta}{sup 5}-pentamethylcyclopentadienyl)rhodium - nucleobase, nucleoside, and nucleotide cyclic trimer hosts via non-covalent {pi}-{pi} and hydrophobic interactions in water: Steric, electronic, and conformational parameters  

SciTech Connect

Molecular recognition, via non-covalent processes such as hydrogen bonding, {pi}-{pi}, and hydrophobic interactions, is an important biological phenomenon for guests, such as drugs, proteins, and other important biological molecules with, for example, host DNA/RNA. We have studied a novel molecular recognition process using guests that encompass aromatic and aliphatic amino acids [L-alanine, L-glutamine (L-Gln), L-histidine, L-isoleucine(L-Ile), L-leucine(L-Leu), L-phenylalanine(L-Phe), L-proline, L-tryptophan(L-Trp), L-valine(L-Val)], substituted aromatic carboxylic acids o-, m-, p-aminobenzoic acids (G1-3), benzoic acid (G4), phenylacetic acid (G5), p-methoxyphenylacetic acid (G6), o-methyoxybenozoic acid (G9), o-nitrobenzoic acid (G10), and aliphatic carboxylic acids [cyclohexylacetic acid (G7), 1-adamantanecarboxylic acid (G8)] with supramolecular, bioorganometallic hosts, ({eta}{sup 5}-pentamethylcyclopentadienyl)rhodium (Cp{sup *}Rh)-nucleobase, nucleoside, and nucleotide cyclic trimer complexes in aqueous solution at pH 7, utilizing {sup 1}H NMR, NOE, and molecular modeling techniques, and, as well, determining association constants (K{sub a}) and free energies of complexation ({Delta}{degree}G). The host-guest complexation occurs predominantly via non-covalent {pi}-{pi}, hydrophobic, and possible subtle H-bonding interactions, with steric, electronic, and molecular conformational parameters as important criteria. 8 refs., 6 figs., 3 tabs.

Chen, H.; Ogo, Seiji; Fish, R.H. [Lawrence Berkeley National Lab., CA (United States)]|[Univ. of California, Berkeley, CA (United States)

1996-05-29

110

Development and analytical application of a glucose biosensor based on glucose oxidase/O-(2-hydroxyl)propyl-3-trimethylammonium chitosan chloride nanoparticle-immobilized onion inner epidermis.  

PubMed

A glucose biosensor comprising a glucose oxidase/O-(2-hydroxyl)propyl-3-trimethylammonium chitosan chloride nanoparticle (O-HTCC NP)-immobilized onion inner membrane and a dissolved oxygen (O(2)) sensor has been successfully developed. The detection scheme is based on the depletion of dissolved O(2) content upon exposure to glucose. The decrease in O(2) level was monitored and related to the glucose concentration. The biosensor shows linear response to glucose from 0.0 to 0.60 mM with a detection limit of 50 microM (S/N=3). The effect of O-HTCC NP and enzyme loading, pH, temperature, and phosphate buffer concentration on the sensitivity of the biosensor was studied in detail. The biosensor exhibits fast response time (70s), good repeatability (3.2%, n=10) and storage stability (90% of initial sensitivity after 3-week storage). Common interferents including acetic acid, lactic acid, propionic acid, butyric acid, folic acid, methanol, glycine, DL-alpha-alanine and DL-cysteine do not cause significant interferences on the biosensor. The proposed biosensor method was successfully applied to determine the glucose content in real samples such as orange juice, red wine and tea drink and the results were comparable to that obtained from a spectrophotometric method. The glucose recovery test demonstrates that the proposed glucose biosensor offers an excellent, accurate and precise method for the determination of glucose in real samples. PMID:20353886

Wang, Fei; Yao, Jun; Russel, Mohammad; Chen, Huilun; Chen, Ke; Zhou, Yong; Ceccanti, Brunello; Zaray, Gyula; Choi, Martin M F

2010-03-06

111

1,2:5,6-Di-O-iso-propyl-idene-3-C-methyl-?-d-allo-furan-ose  

PubMed Central

The title carbohydrate, C13H22O6, is a derivative of d-glycose, in which the furanosidic and isopropylidene rings are in twisted conformations. The mean plane of the furanosidic ring makes a dihedral angle of 70.32?(18) with the mean plane of the fused isopropylidene ring. The methyl groups in the other isopropylidene ring are disordered over two sets of sites, with an occupancy ratio of 0.74?(6):0.26?(6). In the crystal, molecules are linked by OH?O hydrogen bonds into chains with graph-set notation C(5) along [100]. Weak CH?O interactions also occur.

Forezi, Luana da Silva Magalhaes; Silva, Marcos Moitrel Pequeno; Santos, Fernanda da Costa; Ferreira, Vitor Francisco; de Souza, Maria Cecilia Bastos Vieira

2013-01-01

112

40 CFR 721.9516 - Siloxanes and silicones, 3-[(2-aminoethyl) amino]propyl Me, di-Me, reaction products with...  

Code of Federal Regulations, 2013 CFR

...New Uses for Specific Chemical Substances § 721...propyl Me, di-Me, reaction products with polyethylene-polypropylene...glycidal ether. (a) Chemical substance and significant...reporting. (1) The chemical substance identified...propyl Me, di-Me, reaction products with...

2013-07-01

113

Carcinogenesis Bioassay of Propyl Gallate (CAS No. 121-79-9) in F344/N Rats and B6C3F1 Mice (Feed Study).  

National Technical Information Service (NTIS)

A carcinogenesis bioassay of propyl gallate was conducted by feeding diets containing 6,000 or 12,000 ppm propyl gallate to groups of 50 F344/N rats and 50 B6C3F1 mice of each sex for 103 weeks. Groups of 50 untreated rats and 50 untreated mice of each se...

1982-01-01

114

Alkyl phosphonic acids and sulfonic acids in the Murchison meteorite  

NASA Astrophysics Data System (ADS)

Homologous series of alkyl phosphonic acids and alkyl sulfonic acids, along with inorganic orthophosphate and sulfate, are identified in water extracts of the Murchison meteorite after conversion to their t-butyl dimethylsilyl derivatives. The methyl, ethyl, propyl, and butyl compounds are observed in both series. Five of the eight possible alkyl phosphonic acids and seven of the eight possible alkyl sulfonic acids through C4 are identified. Abundances decrease with increasing carbon number as observed of other homologous series indigenous to Murchison. Concentrations range downward from approximately 380 nmol/gram in the alkyl sulfonic acid series, and from 9 nmol/gram in the alkyl phosphonic acid series.

Cooper, George W.; Onwo, Wilfred M.; Cronin, John R.

1992-11-01

115

Methyl propyl carbonate: A promising single solvent for Li-ion battery electrolytes  

SciTech Connect

Methyl propyl carbonate (MPC) solutions containing Li salts can be used as a single-solvent electrolyte with addition of ethylene carbonate (EC). Graphite electrodes can be cycled at high reversible capacity in MPC solutions containing LiPF{sub 6} and LiAsF{sub 6}. The use of acyclic, unsymmetric alkyl carbonate solvents, such as ethyl methyl carbonate (EMC) and MPC in Li-ion based electrolytes, increases the stability of the graphite electrode. Whereas a small amount of EC is still needed as cosolvent in EMC solutions to obtain stable surface films on graphite electrodes, the authors show here that the surface films produced on graphite in MPC solutions (without added EC) are highly stable, allowing reversible Li-ion intercalation. To understand this trend, they investigated the surface chemistry developed on lithium and carbon electrodes in MPC solutions in conjugation with electrochemical studies.

Ein-Eli, Y.; McDevitt, S.F. [Covalent Associates Inc., Woburn, MA (United States); Aurbach, D.; Markovsky, B.; Schechter, A. [Bar-Ilan Univ., Ramat Gan (Israel). Dept. of Chemistry

1997-07-01

116

Control of laser induced molecular fragmentation of n-propyl benzene using chirped femtosecond laser pulses  

PubMed Central

We present the effect of chirping a femtosecond laser pulse on the fragmentation of n-propyl benzene. An enhancement of an order of magnitude for the relative yields of C3H3+ and C5H5+ in the case of negatively chirped pulses and C6H5+ in the case of positively chirped pulses with respect to the transform-limited pulse indicates that in some fragmentation channel, coherence of the laser field plays an important role. For the relative yield of all other heavier fragment ions, resulting from the interaction of the intense laser field with the molecule, there is no such enhancement effect with the sign of chirp, within experimental errors. The importance of the laser phase is further reinforced through a direct comparison of the fragmentation results with the second harmonic of the chirped laser pulse with identical bandwidth.

Goswami, Tapas; Karthick Kumar, S.K.; Dutta, Aveek; Goswami, Debabrata

2009-01-01

117

Rotational spectroscopy, dipole moment and 14N nuclear hyperfine structure of iso-propyl cyanide  

NASA Astrophysics Data System (ADS)

Rotational transitions of iso-propyl cyanide, (CH3)2CHCN, also known as iso-butyronitrile, were recorded using long-path absorption spectroscopy in selected regions between 37 and 600 GHz. Further measurements were carried out between 6 and 20 GHz employing Fourier transform microwave (FTMW) spectroscopy on a pulsed molecular supersonic jet. The observed transitions reach J and Ka quantum numbers of 103 and 59, respectively, and yield accurate rotational constants as well as distortion parameters up to eighth order. The 14N nuclear hyperfine splitting was resolved in particular by FTMW spectroscopy yielding spin-rotation parameters as well as very accurate quadrupole coupling terms. In addition, Stark effect measurements were carried out in the microwave region to obtain a largely revised c-dipole moment component and to improve the a-component. The hyperfine coupling and dipole moment values are compared with values for related molecules both from experiment and from quantum chemical calculations.

Mller, Holger S. P.; Coutens, Audrey; Walters, Adam; Grabow, Jens-Uwe; Schlemmer, Stephan

2011-05-01

118

Microwave studies of three alkylbenzenes: Ethyl, n-propyl, and n-butylbenzene  

NASA Astrophysics Data System (ADS)

The rotational spectra of ethyl, n-propyl, and n-butylbenzene have been observed and analyzed using a high-resolution Fourier transform microwave spectrometer. Only one stable conformation was found for ethylbenzene, in agreement with previous results from Caminati et al. [Mol. Phys. 74, 885 (1991)]. The high sensitivity of the technique allows observation of the rotational spectra of the six 13C isotopes of ethylbenzene in natural abundance. The structural analysis indicates that the dihedral angle between the ethyl group and the ring plane is 88.7+/-0.9. Two conformers have been found for n-propylbenzene as predicted by ab initio calculations while four of the five theoretically predicted conformers [Dickinson et al., J. Chem. Soc., Faraday Trans. 93, 1467 (1997)] have been found for n-butylbenzene.

Mat, Beln; Suenram, Richard D.; Lugez, Catherine

2000-07-01

119

Atropisomerization of di-para-substituted propyl-bridged biphenyl cyclophanes.  

PubMed

The influence of electron donors and electron acceptors of variable strength in the 4 and 4' position of 2 and 2' propyl-bridged axial chiral biphenyl cyclophanes on their atropisomerization process was studied. Estimated free energies ?G()(T) of the rotation around the central biphenyl bond which were obtained from (1)H-NMR coalescence measurements were correlated to the Hammett parameters ?(p) as a measure for electron donor and acceptor strength. It is demonstrated that the resulting nice linear correlation is mainly based on the influence of the different substituents on the ?-system of the biphenyl cyclophanes. By lineshape analysis the rate constants were calculated and by the use of the Eyring equation the enthalpic and entropic contributions were evaluated. Density functional theory calculations show a planar transition state of the isomerization process and the calculated energy barriers based on this reaction mechanism are in good agreement with the experimentally obtained free energies. PMID:23059962

Rotzler, Jrgen; Gsellinger, Heiko; Bihlmeier, Angela; Gantenbein, Markus; Vonlanthen, David; Hussinger, Daniel; Klopper, Wim; Mayor, Marcel

2013-01-01

120

Tetraalkyldiarsines as Potential Precursors for Electronic Materials: Synthesis and Characterization of Various Iso-Propyl Arsenic Compounds.  

National Technical Information Service (NTIS)

Tetrakis(iso-propyl)diarsine was synthesized by the reaction of (i-Pr)AsLi with (i-Pr)2Asl. The lithium salt of the secondary arsine was produced following deprotonation of (i-Pr)2AsH, obtained by reduction of (i-Pr)2AsI, which was prepared by the thermol...

L. F. Brough L. Gang M. A. Lipkovich T. J. Colacot

1994-01-01

121

Tetraalykyldiarsines as Potential Precursors for Electronic Materials: Synthesis and Characterization of Various Iso-Propyl Arsenic Compounds.  

National Technical Information Service (NTIS)

Tetrakis(iso-propyl)diarsine was synthesized by the reaction of (i-Pr)2AsLi with (i-Pr)2AsI. The lithium salt of the secondary arsine was produced following deprotonation of (i-Pr)2AsH, obtained by reduction of (i-Pr)2AsI, which was prepared by the thermo...

H. E. Guard W. S. Rees O. Just

1994-01-01

122

Simultaneous, stability indicating, HPLC-DAD determination of guaifenesin and methyl and propyl-parabens in cough syrup  

Microsoft Academic Search

A stability indicating high performance liquid chromatography procedure has been developed for the simultaneous determination of guaifenesin (GUA), methyl p-hydroxybenzoate (MHB) and propyl p-hydroxybenzoate (PHB) in a commercial cough syrup dosage form. The method was specific and stability indicating as chromatographic conditions were selected to provide adequate separation of GUA, MHB and PHB from the putative degradation products guaiacol (GUAI)

Giorgio Grosa; Erika Del Grosso; Roberta Russo; Gianna Allegrone

2006-01-01

123

Low cost brine tolerant sulfonate and sulfate surfactants having 1,3-dyhydrocharboxy-2-propyl hydrophobic tails  

SciTech Connect

Novel sulfonate and sulfate surfactants which have low interfacial tension at high salinity, and their use in enhanced oil recovery are disclosed. These surfactants may be made from relatively inexpensive intermediates, such as monohydric alcohols and epichlorohydrin. These surfactants have 1,3-dihydrocarboxy-2-propyl hydrophobic tails linked by ethoxy linkages to sulfate or alkyl sulfonate moieties.

Hoskin, D. H.

1985-05-07

124

Ionic galleries: a bilayered host-guest cocrystal of C-propyl pyrogallol[4]arene with an ionic liquid.  

PubMed

We report on a cocrystal between C-propyl pyrogallol[4]arene and the ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate exhibiting a remarkable bilayer topology comprising two unique host-guest complexes resulting from the ionic liquid cation binding in two distinctive orientations relative to the macrocycle. PMID:22531153

Fowler, Drew A; Teat, Simon J; Baker, Gary A; Atwood, Jerry L

2012-04-24

125

Identification of a 23 kDa protein from maize photoaffinity-labelled with 5-azido-[7-3H]indol-3-ylacetic acid.  

PubMed Central

A 23 kDa protein (p23) was identified in microsomal extracts from maize coleoptiles by photoaffinity labelling with 5-azido-[7-3H]indol-3-ylacetic acid ([3H]N3IAA). Labelling of p23 was blocked by unlabelled IAA, N3IAA, indol-3-ylbutyric acid and indol-3-yl-lactate. In addition, labelling was efficiently decreased by tryptophan, as well as by the scavenger p-aminobenzoic acid. Labelling was, however, not affected by synthetic auxins such as 1-naphthylacetic acid or 2,4-dichlorophenoxyacetic acid. Competition data suggest that the label was probably bound via the indole ring, and hence labelling was not specific for auxins. The 23 kDa protein was solubilized from crude microsomes by extraction with Triton X-100 and purified to homogeneity by ion-exchange, size-exclusion and reversed-phase chromatography. After electroblotting, the amino acid sequences of the p23 N-terminus as well as the several tryptic peptides were obtained. Database comparisons revealed sequence identity with a maize manganese superoxide dismutase. We conclude that photoaffinity labelling of p23 was pseudo-affinity, and therefore the binding site for IAA is not specific. Images Figure 1 Figure 2 Figure 3 Figure 4

Feldwisch, J; Zettl, R; Campos, N; Palme, K

1995-01-01

126

Densities and vapor-liquid equilibria in binary mixtures formed by propyl methanoate + ethanol, + propan-1-ol, and + butan-1-ol at 160.0 kPa  

SciTech Connect

Densities and excess volumes were determined at 298.15 K for propyl methanoate + ethanol, + propan-1-ol, and + butan-1-ol. The results of those quantities were then correlated to get the concentrations of vapor-liquid equilibrium obtained isobarically at 160 kPa for the same mixtures. Two mixtures show azeotropes: for propyl methanoate (1) + ethanol (2), x{sub 1} = 0.443 at T = 358.7 K; and for propyl methanoate (1) + propan-1-ol (2), x{sub 1} = 0.762 at T = 368.2 K. The mixtures are thermodynamically consistent, and the predictions made using several group-contribution models are satisfactory.

Falcon, J.; Ortega, J.; Gonzalez, E. [Escuela Superior de Ingenieros Industriales, Las Palmas (Spain). Laboratorio de Termodinamica y Fisicoquimica

1996-07-01

127

Antiviral Evaluation of Octadecyloxyethyl Esters of (S)-3-Hydroxy-2-(phosphonomethoxy)propyl Nucleosides Against Herpesviruses and Orthopoxviruses?  

PubMed Central

Our previous studies showed that esterification of (S)-3-hydroxy-2-(phosphono-methoxy)propyl]adenine (HPMPA) or 1-(S)-[3-hydroxy-2-(phosphonomethoxy)-propyl]cytosine (HPMPC) with alkoxyalkyl groups such as hexadecyloxypropyl (HDP) or octadecyloxyethyl (ODE) resulted in large increases in antiviral activity and oral bioavailability. The HDP- and ODE- esters of HPMPA were shown to be active in cells infected with human immunodeficiency virus, type 1 (HIV-1), while HPMPA itself was virtually inactive. To explore this approach in greater detail, we synthesized four new compounds in this series, the ODE esters of 9-(S)-[3-hydroxy-2-(phosphonomethoxy)-propyl]guanine (HPMPG), 1-(S)-[3-hydroxy-2-(phosphono-methoxy)propyl]thymine (HPMPT), 9-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]-2,6-diaminopurine (HPMPDAP) and 9-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]-2-amino-6-cyclopropylaminopurine. (HPMP-cPrDAP) and evaluated their antiviral activity against herpes simplex virus, type 1 (HSV-1), human cytomegalovirus (HCMV), and vaccinia, cowpox and ectromelia. Against HSV-1, subnanomolar EC50 values were observed with ODE-HPMPA and ODE-HPMPC while ODE-HPMPG had intermediate antiviral activity with an EC50 of 40 nanomolar. In HFF cells infected with HCMV, the lowest EC50 values were observed with ODE-HPMPC, 0.9 nanomolar. ODE -HPMPA was highly active with an EC50 of 3 nanomolar, while ODE-HPMPG and ODE-HPMPDAP were also highly active with EC50s of 22 and 77 nanomolar, respectively. Against vaccinia and cowpox viruses, ODE-HPMPG and ODE-HPMPDAP were the most active and selective compounds with EC50 values of 20 to 60 nanomolar and selectivity index values of 600 to 3,500. ODE-HPMPG was also active against ectromelia virus with an EC50 value of 410 nanomolar and a selectivity index value of 166. ODE-HPMPG and ODE-HPMPDAP are proposed for further preclinical evaluation as possible candidates for treatment of HSV, HCMV or orthopoxvirus diseases.

Valiaeva, Nadejda; Prichard, Mark N.; Buller, R. Mark; Beadle, James R.; Hartline, Caroll B.; Keith, Kathy A.; Schriewer, Jill; Trahan, Julissa; Hostetler, Karl Y.

2009-01-01

128

Antiviral evaluation of octadecyloxyethyl esters of (S)-3-hydroxy-2-(phosphonomethoxy)propyl nucleosides against herpesviruses and orthopoxviruses.  

PubMed

Our previous studies showed that esterification of 9-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]adenine (HPMPA) or 1-(S)-[3-hydroxy-2-(phosphonomethoxy)-propyl]cytosine (HPMPC) with alkoxyalkyl groups such as hexadecyloxypropyl (HDP) or octadecyloxyethyl (ODE) resulted in large increases in antiviral activity and oral bioavailability. The HDP and ODE esters of HPMPA were shown to be active in cells infected with human immunodeficiency virus, type 1 (HIV-1), while HPMPA itself was virtually inactive. To explore this approach in greater detail, we synthesized four new compounds in this series, the ODE esters of 9-(S)-[3-hydroxy-2-(phosphonomethoxy)-propyl]guanine (HPMPG), 1-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]thymine (HPMPT), 9-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]-2,6-diaminopurine (HPMPDAP) and 9-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]-2-amino-6-cyclopropylaminopurine (HPMP-cPrDAP) and evaluated their antiviral activity against herpes simplex virus, type 1 (HSV-1), human cytomegalovirus (HCMV), and vaccinia, cowpox and ectromelia. Against HSV-1, subnanomolar EC(50) values were observed with ODE-HPMPA and ODE-HPMPC while ODE-HPMPG had intermediate antiviral activity with an EC(50) of 40 nM. In HFF cells infected with HCMV, the lowest EC(50) values were observed with ODE-HPMPC, 0.9 nM. ODE-HPMPA was highly active with an EC(50) of 3 nM, while ODE-HPMPG and ODE-HPMPDAP were also highly active with EC(50)s of 22 and 77 nM, respectively. Against vaccinia and cowpox viruses, ODE-HPMPG and ODE-HPMPDAP were the most active and selective compounds with EC(50) values of 20-60 nM and selectivity index values of 600-3500. ODE-HPMPG was also active against ectromelia virus with an EC(50) value of 410 nM and a selectivity index value of 166. ODE-HPMPG and ODE-HPMPDAP are proposed for further preclinical evaluation as possible candidates for treatment of HSV, HCMV or orthopoxvirus diseases. PMID:19800369

Valiaeva, Nadejda; Prichard, Mark N; Buller, R Mark; Beadle, James R; Hartline, Caroll B; Keith, Kathy A; Schriewer, Jill; Trahan, Julissa; Hostetler, Karl Y

2009-10-01

129

In vitro bioactivity and biocompatibility of calcium phosphate cements using Hydroxy-propyl-methyl-Cellulose (HPMC)  

NASA Astrophysics Data System (ADS)

In this study, the bioactivity and biocompatibility of new calcium phosphate bone cements (CPC) using Hydroxy-propyl-methyl-Cellulose (HPMC) was evaluated to understand the effect of HPMC on bone-bonding apatite formation and biocompatibility. In vitro bioactivity was investigated by incubating the CPC samples containing different ratios of HPMC (0%, 2% and 4% HPMC) in simulated body fluid (SBF) for 2, 7, 14 and 28 days. The formation of bone like apatite was confirmed on CPC surfaces by SEM and XRD analysis. Higher HPMC content of CPC showed faster apatite deposition in SBF. A high Ca ion dissolution profile was also reported with an increase of pH in all samples in SBF. The apatite formation ability of these CPC samples was found to be dependent on both surface chemistry and immersion time in SBF. The In vitro cytotoxicity test showed that the CPC samples with 4% HPMC were fairly cytocompatible for fibroblast L-929 cells. SEM images showed that MG-63 cells were successfully attached to the CPC samples and well proliferated.

Jyoti, M. Anirban; Thai, Van Viet; Min, Young Ki; Lee, Byong-Taek; Song, Ho-Yeon

130

Functionalization of single-walled carbon nanotubes with N-[3-(trimethoxysilyl)propyl]ethylenediamine and its cobalt complex  

Microsoft Academic Search

The reaction of N-[3-(trimethoxysilyl)propyl]ethylenediamine with fluorinated carbon nanotubes (F-CNT) produced the corresponding aminoalkylalkoxysilane functionalized carbon nanotubes. Cobalt salt is then complexed to this functionalized carbon nanotubes by the addition of cobalt chloride to form cobalt complexed nanocomposite in high yield. This composite and precursors were characterized by using Fourier transform infra-red spectroscopy (FTIR), transmission electron microscopy (TEM), energy dispersive spectral

Aderemi Oki; Luqman Adams; Zhipping Luo; Edigin Osayamen; Paul Biney; Valery Khabashesku

2008-01-01

131

New methodology for Ozone Depletion Potentials of short-lived compounds: n-Propyl bromide as an example  

Microsoft Academic Search

A number of the compounds proposed as replacements for substances controlled under the Montreal Protocol have extremely short atmospheric lifetimes, on the order of days to a few months. An important example is n-propyl bromide (also referred to as 1-bromopropane, CH2BrCH2CH 3 or simplified as 1-C3H7Br or nPB). This compound, useful as a solvent, has an atmospheric lifetime of less

Donald J. Wuebbles; Kenneth O. Patten; Matthew T. Johnson; Rao Kotamarthi

2001-01-01

132

Induction of specific-locus and dominant lethal mutations in male mice by n-propyl and isopropyl methanesulfonate  

Microsoft Academic Search

n-Propyl methanesulfonate (nPMS) and isopropyl methanesulfonate (iPMS) induce dominant lethal and specific-locus mutations in male mice. The responses of the various spermatogenic stages to the induction of mutations differ markedly for nPMS and iPMS. Independent of the effective dose range the induction of dominant lethal mutations by nPMS is limited to spermatozoa and spermatids. In contrast, the induction of dominant

U. H. Ehling; A. Neuhuser-Klaus

1995-01-01

133

DNA Strand Break Induction and Enhanced Cytotoxicity of Propyl Gallate in the Presence of Copper(II)  

Microsoft Academic Search

The antioxidant propyl gallate (PG) induced single strand breaks in PM2 DNA at concentrations higher than 0.25 ?M when it was combined with copper concentrations at 5 ?M and above. In combination with 100 ?M CuCl2, extensive double strand breakage was also observed. Neither PG alone nor CuCl2 showed any strand breaking properties. DNA strand breakage was inhibited by addition

Heike Jacobi; Britta Eicke; Irene Witte

1998-01-01

134

Highly efficient antifouling ultrafiltration membranes incorporating zwitterionic poly([3-(methacryloylamino)propyl]-dimethyl(3-sulfopropyl) ammonium hydroxide)  

Microsoft Academic Search

A novel membrane material based on random copolymer composed of poly(acrylonitrile-([3-(methacryloylamino)propyl]-dimethyl(3-sulfopropyl) ammonium hydroxide)) (PANMPDSAH) was synthesized by the water phase suspension polymerization. The zwitterionic PAN-based membranes were prepared through blending PAN and PANMPDSAH copolymer by a phase inversion method. The zwitterionic PAN-based membranes have higher hydrophilicity and wettability, and lower protein adsorption in comparison with the control PAN membrane. Ultrafiltration

Lijun Wang; Yan-lei Su; Lili Zheng; Wenjuan Chen; Zhongyi Jiang

2009-01-01

135

The Ozone Productivity of n-Propyl Bromide: Part 2An Exception to the Maximum Incremental Reactivity Scale  

Microsoft Academic Search

In an earlier paper the ozone-forming potential of n-propyl bromide (NPB) was studied with a new methodology designed to address issues associated with a marginal smog-forming compound. However, the U.S. Environmental Protection Agency (EPA) subsequently revised its policy and now recommends using the Maximum Incremental Reactivity (MIR) scale to rank the ozone-forming potential of all volatile organic compounds (VOCs), including

Gary Z. Whitten; Greg Yarwood; Sunhee Lee; Kevin Tory; Dale Hess; Manuela Burgers; Bill Lilley; Richard Baldauf; Eben Thoma; Michael Hays; Richard Shores; John Kinsey; Brian Gullett; Sue Kimbrough; Vlad Isakov; Thomas Long; Richard Snow; Andrey Khlystov; Jason Weinstein; Fu-Lin Chen; Robert Seila; David Olson; Ian Gilmour; Seung-Hyun Cho; Nealson Watkins; Patricia Rowley; Marc Carreras-Sospedra; Donald Dabdub; Jacob Brouwer; Eladio Knipping; Naresh Kumar; Ken Darrow; Anne Hampson; Bruce Hedman; James Droppo; Bruce Napier; Cynthia Howard-Reed; Victor Henzel; Steven Nabinger; Andrew Persily; B. deCastro; Lu Wang; Jana Mihalic; Patrick Breysse; Alison Geyh; Timothy Buckley; M. Garcia; M. Sanchez; Isidro rez; Beatriz Torre; Gui Li; Alex Visscher; Chungching Wang; Min-Der Lin; Chenfang Lin; Seoung Kim; Chivalai Temiyasathit; Victoria Chen; Sun-Kyoung Park; Melanie Sattler; Armistead Russell

2008-01-01

136

Comparison of sodium tetraethylborate and sodium tetra(n-propyl)borate as derivatization reagent for the speciation of organotin and organolead compounds in water samples.  

PubMed

The influence of pH on the propylation with sodium tetra(n-propyl)borate of butyl- and phenyltins as well as for trimethyl- and triethyllead was investigated. Ethylation and propylation with tetraalkylborates were compared with regard to derivatization yields and figures of merit for organotin compounds in real water samples. Similar results for limit of detection (3-12 ng/L as tin), derivatization yield (40-100%) and relative standard deviation of the method (3-10%) were achieved for derivatization with the two tetraalkylborates. Propylation is thus the preferred method for the simultaneous determination of environmentally relevant organotin and organolead compounds. The handling of the hygroscopic and air sensitive reagents NaBEt4 and NaBPr4 was simplified by dissolving them in tetrahydrofurane. The reagent solutions in tetrahydrofurane can be stored for at least one month at 4 degrees C in the dark without observing any decrease in the derivatization efficiency. PMID:11220318

Schubert, P; Rosenberg, E; Grasserbauer, M

2000-02-01

137

Indirect determination of thiamazole with the n -propyl alcohol-ammonium sulfate-H 2 O system by the extraction-flotation of CuSCN  

Microsoft Academic Search

In this paper, a new method for the determination of thiamazole by the extraction-flotation of CuSCN with n-propyl alcohol-ammonium sulfate-H2O system was described. The experiment indicated that in the presence of SCN?, Cu(II) was reduced to Cu(I) by thiamazole because of the formation of CuSCN. In the course of phase separation of n-propyl alcohol from water, the precipitated CuSCN remained

Q. Li; W. Zhao; G. Liu

2008-01-01

138

Stimulation of H+ Efflux and Inhibition of Photosynthesis by Esters of Carboxylic Acids 1  

PubMed Central

Suspensions of mechanically isolated Asparagus sprengeri Regel mesophyll cells were used to investigate the influence of various carboxyester compounds on rates of net H+ efflux in the dark or light and photosynthetic O2 production. Addition of 0.15 to 1.5 millimolar malathion, ?-naphthyl acetate, phenyl acetate, or p-nitrophenyl acetate stimulated H+ efflux and inhibited photosynthesis within 1 minute. In contrast, the more polar esters methyl acetoacetate or ethyl p-aminobenzoate had little or no effect on either of these two processes. A 0.15 millimolar concentration of ?-naphthylacetate stimulated the normal rate of H+ efflux, 0.77 nanomoles H+ per 106 cells per minute by 750% and inhibited photosynthesis by 100%. The four active carboxyester compounds also stimulated H+ efflux after the normal rate of H+ efflux was eliminated with 0.01 milligrams per milliliter oligomycin or 100% N2. Oligomycin reduced the ATP level by 70%. Incubation of cells with malathion, ?-naphthyl acetate, or p-nitrophenyl acetate resulted in the generation of the respective hydrolysis products ethanol, ?-naphthol, and p-nitrophenol. It is proposed that inhibition of photosynthesis and stimulation of H+ efflux result when nonpolar carboxyester compounds enter the cell and generate acidic carboxyl groups when hydrolyzed by esterase enzymes.

Duhaime, Donna E.; Bown, Alan W.

1983-01-01

139

Physiological disposition of aerosolized 4-((3-(4-acetyl-3-hydroxy-2-propylphenoxy)propyl)sulfonyl)-gamma -oxobenzenebutanoate (L-648,051) in rats  

SciTech Connect

/sup 14/C-labeled 4-((3-(4-acetyl-3-hydroxy-2-propylphenoxy)propyl)-sulfonyl)-gamma- oxobenzenebutanoate (L-648,051) was suspended in Freon under pressure and injected into rat lungs via a tracheal cannula. The particle size of the drug was 1 to 5 microns and the mean dose was approximately 0.2 mg/kg. Levels of radioactivity in the lung/trachea declined in a monoexponential manner. Absorption, estimated from radioactivity remaining in the lung and trachea, was 73% in 1 hr and 95% in 4 hr. L-648,051 and its pharmacologically active metabolite L-657,098 (formed by ketoreduction of the butanoic acid moiety of L-648,051) accounted for 96% of the radioactivity in the lung at 10 min after the dose and 91% after 60 min. The lung:plasma concentration ratio of active drug (L-648,051 plus L-657,098) was at least 176:1 at 10 min and 17:1 at 60 min (compared with 1:1 after 2 mg/kg iv) suggesting that aerosol administration of L-648,051 in humans may result in an ideal therapeutic ratio, with high levels of pharmacologically active ingredient in the lung and low levels in the plasma.

Tocco, D.J.; Duncan, A.E.; deLuna, F.A.; Wells, G.

1988-09-01

140

Kinetics of the reduction of pyridinium ions by 2-hydroxy-2-propyl radicals in aqueous solution  

SciTech Connect

Kinetic measurements were made for the reductions of the pyridinium ions derived from pyridine, 4-methylpyridine, 3-hydroxypyridine, nicotinamide, and isonicotinamide as well as 1-methylpyridinium and 1,4-dimethylpyridinium ions by 2-hydroxy-2-propyl radicals, which were generated by the homolytic cleavage of the chromium-carbon bond in (H/sub 2/O)/sub 5/CrC(CH/sub 3/)/sub 2/OH/sup 2 +/. The rate constants (dm/sup 3/ mol/sup -1/ s/sup -1/) at 25.0/sup 0/C and an ionic strength of 1.0M (LiClO/sub 4/) are as follows: pyridinium ion, 9.6 x 10/sup 5/; 1-methylpyridinium ion, 3.7 x 10/sup 5/; 4-methylpyridinium ion, 7.3 x 10/sup 4/; 1,4-dimethylpyridinium ion, less than or equal to1 x 10/sup 4/; 3-hydroxypyridinium ion, 1.4 x 10/sup 8/; 3-(aminocarbonyl)pyridinium ion, 7.9 x 10/sup 8/; 4-(aminocarbonyl)pyridinium ion, 1.2 x 10/sup 9/. The rate constants are reasonably well correlated by the Hammett p-sigma equation with p = +8.5. The first two compounds show a second kinetic term corresponding to the rate law k'(Cr/sup 2 +/)(pyH/sup +/)(.C-(CH/sub 3/)/sub 2/OH)(H/sup +/)/sup -1/, consistent with reduction of a Cr(II)-pyridine complex by the free radical.

Shimura, M.; Espenson, J.H.

1983-01-19

141

Protection against radiation-induced damage of 6-propyl-2-thiouracil (PTU) in thyroid cells.  

PubMed

Many epidemiologic studies have shown that the exposure to high external radiation doses increases thyroid neoplastic frequency, especially when given during childhood or adolescence. The use of radioprotective drugs may decrease the damage caused by radiation therapy and therefore could be useful to prevent the development of thyroid tumors. The aim of this study was to investigate the possible application of 6-propyl-2-thiouracil (PTU) as a radioprotector in the thyroid gland. Rat thyroid epithelial cells (FRTL-5) were exposed to different doses of ? irradiation with or without the addition of PTU, methimazole (MMI), reduced glutathione (GSH) and perchlorate (KClO4). Radiation response was analyzed by clonogenic survival assay. Cyclic AMP (cAMP) levels were measured by radioimmunoassay (RIA). Apoptosis was quantified by nuclear cell morphology and caspase 3 activity assays. Intracellular reactive oxygen species (ROS) levels were measured using the fluorescent dye 2',7'-dichlorofluorescein-diacetate. Catalase, superoxide dismutase and glutathione peroxidase activities were also determined. Pretreatment with PTU, MMI and GSH prior to irradiation significantly increased the surviving cell fraction (SF) at 2 Gy (P < 0.05), while no effect was observed with KClO4. An increase in extracellular levels of cAMP was found only in PTU treated cells in a dose and time-dependent manner. Cells incubated with agents that stimulate cAMP (forskolin and dibutyril cAMP) mimicked the effect of PTU on SF. Moreover, pretreatment with the inhibitor of protein kinase A, H-89, abolished the radioprotective effect of PTU. PTU treatment diminished radiation-induced apoptosis and protected cells against radiation-induced ROS elevation and suppression of the antioxidant enzyme's activity. PTU was found to radioprotect normal thyroid cells through cAMP elevation and reduction in both apoptosis and radiation-induced oxidative stress damage. PMID:23398355

Perona, Marina; Dagrosa, Mara A; Pagotto, Romina; Casal, Mariana; Pignataro, Omar P; Pisarev, Mario A; Juvenal, Guillermo J

2013-02-11

142

Autoradiographic localization of sigma receptor binding sites in guinea pig and rat central nervous system with (+)3H-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine  

SciTech Connect

(+)3H-3-PPP ((+)3H-3-(3-Hydroxyphenyl)-N-(1-propyl)-piperidine) binds with high affinity to brain membranes with a pharmacological profile consistent with that of sigma receptors. The distribution of (+)3H-3-PPP binding sites in brain and spinal cord of both guinea pig and rat has been determined by in vitro autoradiography with binding densities quantitated by computer-assisted densitometry. (+)3H-3-PPP binding to slide-mounted brain sections is saturable and displays high affinity and a pharmacological specificity very similar to sites labeled in homogenates. (+)3H-3-PPP binding sites are heterogeneously distributed. Highest concentrations of binding sites occur in spinal cord, particularly the ventral horn and dorsal root ganglia; the pons-medulla, associated with the cranial nerve and pontine nuclei and throughout the brain stem reticular formation; the cerebellum, over the Purkinje cell layer; the midbrain, particularly the central gray and red nucleus; and hippocampus, over the pyramidal cell layer. Lowest levels are seen in the basal ganglia and parts of the thalamus, while all other areas, including hypothalamus and cerebral cortex, exhibit moderate grain densities. Quinolinic acid-induced lesions of the hippocampus indicate that (+)3H-3-PPP labels hippocampal pyramidal cells and granule cells in the dentate gyrus. Intrastriatal injection of ibotenic acid dramatically reduces (+)3H-3-PPP binding in this area, while injection of 6-hydroxydopamine produces a relatively slight decrease. The distribution of (+)3H-3-PPP binding sites does not correlate with the receptor distribution of any recognized neurotransmitter or neuropeptide, including dopamine. However, there is a notable similarity between the distribution of (+)3H-3-PPP sites and high-affinity binding sites for psychotomimetic opioids, such as the benzomorphan (+)SKF 10,047.

Gundlach, A.L.; Largent, B.L.; Snyder, S.H.

1986-06-01

143

The antinociceptive properties of the novel compound ()-trans-4-hydroxy-6-propyl-1-oxocyclohexan-2-one in acute pain in mice.  

PubMed

The compound ()-trans-4-hydroxy-6-propyl-1-oxocyclohexan-2-one [()-?-lactone] was isolated from the plant Vitex cymosa Bertero, and determined to be the active principle. The present study aimed to evaluate the antinociceptive effect of ()-?-lactone and to elucidate its mechanism of action. Mice were subjected to in-vivo models of acute pain (acetic acid-induced abdominal writhing, formalin and hot-plate tests) and the open-field test. ()-?-Lactone, administered orally (6-900 mol/kg), exerted a dose-dependent antinociceptive effect in the acetic acid-induced abdominal writhing, formalin and hot-plate tests. ()-?-Lactone administered by the intrathecal (i.t.) and subplantar (s.p.) routes (10-600 nmol) exerted concentration-dependent antinociceptive effects in the formalin test, showing its spinal and peripheral activity, respectively. In the hot-plate test, ()-?-lactone was also active when administered i.t., confirming its spinal effect. The previous intraperitoneal (i.p.) application of naloxone, yohimbine, mecamylamine or glibenclamide did not alter the effect produced by the i.t. administration of ()-?-lactone, whereas the previous application of atropine and L-arginine significantly reduced its effects in the formalin and hot-plate tests. The previous i.p. application of L-NAME enhanced the antinociceptive effect of the i.t. administration of ()-?-lactone in the formalin and hot-plate tests. The previous i.p. application of L-NAME and L-arginine increased and decreased, respectively, the activity of ()-?-lactone administered by s.p. administration. These results indicate that ()-?-lactone has significant spinal and peripheral antinociceptive activity, and that its effects are at least partially mediated by a reduced nitric oxide production/release, most likely through mechanisms involving the cholinergic system. PMID:23263483

Marinho, Bruno G; Miranda, Leandro S M; da S Costa, Jernimo; Leito, Suzana G; Vasconcellos, Mrio L A A; Pereira, Vera L P; Fernandes, Patricia D

2013-02-01

144

Detailed modeling of low-temperature propane oxidation: 1. The role of the propyl + O(2) reaction.  

PubMed

Accurate description of reactions between propyl radicals and molecular oxygen is an essential prerequisite for modeling of low-temperature propane oxidation because their multiple reaction pathways either accelerate the oxidation process via chain branching or inhibit it by forming relatively stable products. The CBS-QB3 level of theory was used to construct potential energy surfaces for n-C(3)H(7) + O(2) and i-C(3)H(7) + O(2). High-pressure rate constants were calculated using transition state theory with corrections for tunneling and hindered rotations. These results were used to derive pressure- and temperature-dependent rate constants for the various channels of these reactions under the framework of the Quantum Rice-Ramsperger-Kassel (QRRK) and the modified strong collision (MSC) theories. This procedure resulted in a thermodynamically consistent C(3)H(7) + O(2) submechanism, which was either used directly or as part of a larger extended detailed kinetic mechanism to predict the loss of propyl and the product yields of propylene and HO(2) over a wide range of temperatures, pressures, and residence times. The overall good agreement between predicted and experimental data suggests that this reaction subset is reliable and should be able to properly account for the reactions of propyl radicals with O(2) in propane oxidation. It is also demonstrated that for most conditions of practical interest only a small subset of reactions (e.g., isomerization, concerted elimination of HO(2), and stabilization) controls the oxidation kinetics, which makes it possible to considerably simplify the mechanism. Moreover, we observed strong similarities in the rate coefficients within each reaction class, suggesting the potential for development of relatively simple rate constant estimation rules that could be applied to analogous reactions involving hydrocarbon radicals that are too large to allow accurate detailed electronic structure calculations. PMID:20509639

Huynh, Lam K; Carstensen, Hans-Heinrich; Dean, Anthony M

2010-06-24

145

Garlic derivative propyl propane thiosulfonate is effective against broiler enteropathogens in vivo.  

PubMed

Two experiments were carried out to study the effects of dietary supplementation with the garlic (Allium sativum)-derived product propyl propane thiosulfonate (PTS-O) on the intestinal log(10) number of copies of enteropathogens in broiler chickens, together with their intestinal morphology and growth performance. The additive had no significant effect on feed intake at any dose assayed. In experiment 1 (1 to 21 d of age), the BW of chickens fed on 45 mg of PTS-O/kg of diet was higher (P < 0.01) than that of controls. Birds fed on diets containing 45 and 90 mg of PTS-O/kg of diet had improved (P < 0.01) feed:gain ratios compared with the controls at 21 d of age. Ileal villus height, width and surface area, mucosal thickness, and muscular layer thickness were considerably greater (P < 0.01) than control values in chickens fed 90 mg of PTS-O/kg of diet. The Clostridium perfringens log(10) number of counts was not significantly affected at any dose assayed. The inclusion of PTS-O at both concentrations (45 and 90 mg/kg of diet) resulted in lower (P < 0.01) log(10) number of copies of ileal Salmonella spp. and crop enterobacteria and Escherichia coli. The inclusion of 90 mg of PTS-O/kg of diet also resulted in lower (P < 0.01) enterobacteria and E. coli log(10) numbers of copies in the ileal and cecal contents, respectively. The number of copies of Campylobacter jejuni was not significantly affected. In experiment 2 (15 to 28 d of age), lower (P < 0.01) log(10) number of copies of Salmonella spp. and C. jejuni were determined in the ileal contents of chickens fed on diets containing 135 mg of PTS-O/kg of diet. The addition of 90 mg of PTS-O/kg of diet lowered (P < 0.01) only the number of copies of ileal Salmonella spp. This investigation confirmed previous in vitro data and showed that PTS-O lowered the intestinal numbers of enteropathogens and improved the ileal histological structure and productive parameters of broilers. PMID:22912448

Peinado, M J; Ruiz, R; Echvarri, A; Rubio, L A

2012-09-01

146

Preliminary evaluation of an in utero-lactation assay using 6-n-propyl-2-thiouracil.  

PubMed

In this preliminary study, the potential of an in utero-lactation assay to detect thyroid effectors was evaluated by treating three dams/group with 6-n-propyl-2-thiouracil (PTU), a known thyroid antagonist, by oral gavage at doses of 0, 0.0032, 0.016, 0.08 and 0.4 mg/kg/day during fetal organogenesis and lactation. Hearing disturbances and an elevated relative thyroid weight were observed in offspring of both sexes in the 0.4 mg/kg/day group. The Biel-type water T-maze test showed an increase in the number of errors made by females in the 0.4 mg/kg/day group. Histopathologically, flattening of follicular epithelium, a decrease in resorptive colloid droplets, degeneration of follicular epithelium, and hyperplasia of follicular epithelium were observed in males belonging to the 0.4 mg/kg/day group. Histopathological abnormalities were also observed in some offspring belonging to the 0.08 mg/kg/day group. In the dams, hypertrophy of the follicular epithelium of the thyroid was observed in the 0.4 mg/kg/day group. Although we could not explain the mechanism for the difference in the effects seen in the offspring and the dams, the effect of PTU in utero through lactational exposure is apparently different from that resulting from exposure in homeostatically mature rats. Most reports studying PTU have involved administration in water or in food, and reports on the oral gavage of PTU during the fetal organogenesis and lactation period are very rare. This assumes that dosages >0.4 mg/kg/day would also produce clear anti-thyroid effects by oral gavage and, possibly, emphasizes that dosages <0.4 mg/kg/day did not have a noticeable effect. Based on the present results, a study to determine the reproducibility of the data in a much larger number of dams will be performed to confirm the findings in the present study, and to evaluate other endpoints, such as hormonal evaluation of dams and their offspring, sexual developmental landmarks, and fertility of the offspring. PMID:15800759

Noda, Shuji; Muroi, Takako; Takakura, Saori; Sakamoto, Satoko; Takatsuki, Mineo; Yamasaki, Kanji; Tateyama, Susumu; Yamaguchi, Ryoji

2005-03-31

147

[Antioxidative activity of thiophane [bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propyl)sulfide].  

PubMed

The antioxidant activity, mutagenicity, and genotoxicity of bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propyl)sulfide (thiophane) were studied using bacterial tests. The results of both an Ames test and SOS chromotest, as well as those studying the survival of E. coli cells deficient in enzymes responsible for the repair of DNA oxidative damage, testify to the fact that thiophane is not mutagenic and genotoxic, and it protects Salmonella typhimurium cells better than the well-known antioxidant trolox. PMID:19621058

Ovchinnikova, L P; Rotskaia, U N; Vasiunina, E A; Sinitsina, O I; Kandalintseva, N V; Prosenko, A E; Nevinski?, G A

148

Synthesis of propyl and 2-aminoethyl glycosides of alpha-D-galactosyl-(1-->3')-beta-lactoside.  

PubMed

Propyl and 2-aminoethyl alpha-D-galactopyranosyl-(1-->3')-beta-lactosides (1 and 2) were prepared from the corresponding perbenzylated trisaccharide allyl glycoside 6 which, in turn, was obtained by methyl triflate promoted alpha-galactosylation of benzylated allyl lactoside acceptor 4 with thiogalactoside 3. Transformation of the allyl moiety in compound 6 into 2-azidoethyl one was achieved by cleavage of the double bond followed by reduction into alcohol 9, subsequent mesylation, and mesylate-->azide substitution. Alternatively trisaccharide 2 was synthesized using alpha-galactosylation of selectively benzoylated 2-azidoethyl lactoside 19 with 3 as the key step. PMID:11438093

Yudina, O N; Sherman, A A; Nifantiev, N E

2001-06-15

149

ARTICLES: Vapor-Liquid Equilibrium Data of Carbon Dioxide+Methyl Propionate and Carbon Dioxide+Propyl Propionate Systems  

NASA Astrophysics Data System (ADS)

High-pressure vapor-liquid equilibrium data for the binary systems of methyl propionate+carbon dioxide and propyl propionate+carbon dioxide were measured at pressure from 1.00 MPa to 12.00 MPa and temperature in the range from 313 K to 373 K. Experimental results were correlated with the Peng-Robinson equation of state with the two-parameter van der Waals mixing rule. At the same time, the Henry's coefficient, partial molar enthalpy change and partial molar entropy change of CO2 during dissolution at different temperature were also calculated.

Xu, Wei; Xie, Chuan-xin; Li, Hong-ling; Tian, Yi-ling

2010-06-01

150

Fungicidal Activities of Dihydroferulic Acid Alkyl Ester Analogs  

Technology Transfer Automated Retrieval System (TEKTRAN)

The natural product dihydroferulic acid (DFA, 1) and the synthesized DFA methyl (4a), ethyl (4b), propyl (4c), hexyl (4d), octyl (4e), and decyl (4f) esters were examined for antifungal activity. Test fungi included Saccharomyces cerevisiae (wild type, and deletion mutants slt2' and bck1'), Aspergil...

151

Solid-Surface Luminescence Analysis. Progress Report, 1 June 1983-31 October 1985.  

National Technical Information Service (NTIS)

The various subjects studied in this report are: spectral techniques in the study of hydroxyl aromatics and aromatic hydrocarbons; room temperature phosphorescence lifetimes and intensities of p-aminobenzoic acid; quantum efficiencies; solvent interaction...

R. J. Hurtubise

1985-01-01

152

Solid Surface Luminescence Analysis. Progress Report, April 1984-December 1984.  

National Technical Information Service (NTIS)

By using luminescence intensity and phosphorescence lifetimes, it was discovered that there are at least two mechanisms responsible for the room-temperature phosphorescence of p-aminobenzoic acid adsorbed on sodium acetate-sodium chloride mixtures. Signif...

R. J. Hurtubise

1985-01-01

153

Derivatives of Gallic Acid Induce Apoptosis in Tumoral Cell Lines and Inhibit Lymphocyte Proliferation  

Microsoft Academic Search

The effect of gallic acid (3,4,5-trihydroxybenzoic acid) and its alkyl esters (methyl, propyl, octyl, and lauryl) has been studied on several tumoral and nontumoral cells. Three types of behavior have been observed; the first type is represented by the mouse B cell lymphoma Wehi 231 cell line in which death occurs according to the biochemical characteristics of classical apoptosis showing

Antonio Serrano; Carmen Palacios; Garbie Roy; Constantino Cespn; Mar??a L. Villar; Mercedes Nocito; Pedro Gonzlez-Porqu

1998-01-01

154

Conformations and Barriers to Methyl Group Internal Rotation in Two Asymmetric Ethers: Propyl Methyl Ether and Butyl Methyl Ether  

NASA Astrophysics Data System (ADS)

The conformational preferences of the O-C-C-C unit are important in many biological systems with the unit generally preferring a gauche configuration compared to an anti configuration. Butyl methyl ether and propyl methyl ether provide very simple systems for this phenomenom to manifest. Pure rotational spectra of the title molecules have been recorded using chirped pulse Fourier transform microwave spectroscopy (CP-FTMW). In the case of butyl methyl ether, only one conformer has been observed. This conformer has torsional angles of COCC = 180, OCCC = 62 and CCCC = 180 (anti-gauche-anti) and rotational constants of A = 10259.4591(33) MHz, B = 1445.6470(13) MHz, and C = 1356.2944(14) MHz. The rotational spectrum was doubled and has been analyzed to produce an effective barrier to methyl group internal rotation of 780(35) cm-1. A prior rotational spectroscopic study on propyl methyl ether had focused only on the high energy anti-anti conformer. We have analyzed spectra from the lowest energy anti-gauche conformer and the spectroscopic constants will be presented. A summary of the differences in conformational energies and methyl group internal rotation barriers for the class of aliphatic asymmetric ethers will be presented. K. N. Houk, J. E. Eksterowicz, Y.-D. Wu, C. D. Fuglesang, D. B. Mitchell. J. Am. Chem. Soc. 115 (4170), 1993. Hiroshi Kato, Jun Nakagawa, Michiro Hayashi. J. Mol. Spectrosc. 80 (272), 1980.

Long, B. E.; Dechirico, F.; Cooke, S. A.

2012-06-01

155

1,3-Bis(3-ammonium-propyl)tetramethyldisiloxane-sulfate: Structural characterization and evaluation of some properties  

NASA Astrophysics Data System (ADS)

1,3-Bis(3-ammonium-propyl)tetramethyldisiloxane sulfate resulted from the reaction between 1,3-bis(3-aminopropyl)tetramethyldisiloxane with a proper transition metal (iron(III) or vanadium(IV) oxide) salt as anion generator and a carbonylic compound (4-imidazole carboxaldehyde or 2-hydroxybenzaldehyde) as a metal collector, in methanol, was thoroughly characterized. The compound's structure was proved by single-crystal X-ray diffraction and spectral (FT-IR, 1H NMR) analysis, while the thermal behavior was evaluated by thermogravimetry. Water vapor sorption capacity on the crystalline compound was measured in dynamic regime. The co-existence of hydrophobic bis(propyl)tetramethyldisiloxane moiety and telechelic hydrophilic groups constitutes a premise for surface activity, as confirmed by tensiometry. Formation of micelles and aggregates in solution was emphasized by dynamic light scattering and confirmed by AFM images taken on the spin coated films, both revealing closed values for size of the micelles (100-200 nm).

Nistor, Alexandra; Soroceanu, Alina; Shova, Sergiu; Cazacu, Maria

2012-08-01

156

Pharmacokinetics and metabolism of N-[N-[3-(3-hydroxy-4-methoxyphenyl) propyl]-?-aspartyl]-L-phenylalanine 1-methyl ester, monohydrate (advantame) in the rat, dog, and man.  

PubMed

The pharmacokinetics and metabolism of advantame were evaluated in rats, dogs, and humans. The oral pharmacokinetic studies using (14)C-advantame showed that advantame undergoes rapid but incomplete absorption, with an oral bioavailability of total radioactivity in the range of 4-23%. Data indicated that absorption was mainly as ANS9801-acid (de-esterified advantame), which was formed in the gastrointestinal tract as a result of the hydrolysis of the methyl ester group of the parent compound. In the dog, plasma ANS9801-acid was present largely in the form of an unidentified conjugate. Advantame (chiefly in the form of metabolites) was mainly excreted in the feces in rats, dogs, and humans (>80% in each species), with urinary excretion representing a minor route. The predominant metabolite of (14)C-advantame detected in the feces and the urine of rats, dogs, and humans was ANS9801-acid, with lower amounts of 3-[3-hydroxy-4-methoxyphenyl]-1-propylamine (termed HU-1) or N-(3-(3-hydroxy-4-methoxy phenyl))propyl-L-aspartic acid (termed HF-1) present, as well as other minor metabolites and areas of indistinct radioactivity. ANS9801-acid, HU-1, and HF-1 were detected and identified in the urine of rats, humans, and dogs, while ANS9801-acid and HF-1 were identified in the feces of humans and dogs. In the feces of rats, in addition to ANS9801-acid, other additional metabolites were detected, including demethylated ANS9801-acid (designated as RF-1) and another unidentified metabolite (designated as RF-2). Overall, the data show generally similar pharmacokinetics of advantame and ANS9801-acid in animals and in humans and close similarity with neotame. Metabolites of advantame that occur in humans are also found in the 2 species utilized in the toxicology studies, and the metabolism studies support the interpretation of safety data from studies conducted in rats and dogs. PMID:22036030

Ubukata, K; Nakayama, A; Mihara, R

2011-11-01

157

Biocontrol of avocado dematophora root rot by antagonistic Pseudomonas fluorescens PCL1606 correlates with the production of 2-hexyl 5-propyl resorcinol.  

PubMed

A collection of 905 bacterial isolates from the rhizospheres of healthy avocado trees was obtained and screened for antagonistic activity against Dematophora necatrix, the cause of avocado Dematophora root rot (also called white root rot). A set of eight strains was selected on the basis of growth inhibitory activity against D. necatrix and several other important soilborne phytopathogenic fungi. After typing of these strains, they were classified as belonging to Pseudomonas chlororaphis, Pseudomonas fluorescens, and Pseudomonas putida. The eight antagonistic Pseudomonas spp. were analyzed for their secretion of hydrogen cyanide, hydrolytic enzymes, and antifungal metabolites. P. chlororaphis strains produced the antibiotic phenazine-1-carboxylic acid and phenazine-1-carboxamide. Upon testing the biocontrol ability of these strains in a newly developed avocado-D. necatrix test system and in a tomato-F oxysporum test system, it became apparent that P. fluorescens PCL1606 exhibited the highest biocontrol ability. The major antifungal activity produced by strain P. fluorescens PCL1606 did not correspond to any of the major classes of antifungal antibiotics produced by Pseudomonas biocontrol strains. This compound was purified and subsequently identified as 2-hexyl 5-propyl resorcinol (HPR). To study the role of HPR in biocontrol activity, two Tn5 mutants of P. fluorescens PCL1606 impaired in antagonistic activity were selected. These mutants were shown to impair HRP production and showed a decrease in biocontrol activity. As far as we know, this is the first report of a Pseudomonas biocontrol strain that produces HPR in which the production of this compound correlates with its biocontrol activity. PMID:16610745

Cazorla, Francisco M; Duckett, Simon B; Bergstrm, Ed T; Noreen, Sadaf; Odijk, Roeland; Lugtenberg, Ben J J; Thomas-Oates, Jane E; Bloemberg, Guido V

2006-04-01

158

Enzymatic propyl gallate synthesis in solvent-free system: Optimization by response surface methodology  

Microsoft Academic Search

The ability of a non-commercial immobilized Staphylococcus xylosus lipase to catalyze the esterification of propanol with gallic acid was investigated and the antioxidant as well as the antimicrobial activities of the ester formed were evaluated. The response surface methodology, based on a three variables BoxBehnken design (reaction temperature, enzyme amount and 1-propanol\\/gallic acid molar ratio), was used to optimize the

Ahlem Bouaziz; Habib Horchani; Nadia Ben Salem; Ali Chaari; Moncef Chaabouni; Youssef Gargouri; Adel Sayari

2010-01-01

159

5-Fluoro-3-phenyl-N?-(4-propyl-cyclo-hexyl-idene)-1H-indole-2-carbohydrazide  

PubMed Central

In the title compound, C24H26FN3O, the cyclohexane ring adopts a chair conformation; the propyl substituent is in an equatorial orientation and the bond-angle sum at the C atom bonded to the carbohydrazide N atom is 360.0. The dihedral angle between the 1H-indole ring system and the phenyl ring is 82.77?(13). A weak intramolecular CH?? contact occurs. In the crystal, pairs of molecules related by a crystallographic twofold axis are linked by bifurcated NH?(O,N) hydrogen bonds; a CH?O interaction occurs between the same pair. The dimers are linked by CH?F and CH?? interactions, generating a three-dimensional network.

Celikesir, Sevim Turktekin; Akkurt, Mehmet; Ustundag, Gokce Cihan; Buyukgungor, Orhan

2013-01-01

160

(3E,5E)-3,5-Bis(2-chloro-benzyl-idene)-1-propyl-piperidin-4-one  

PubMed Central

The title compound, C22H21Cl2NO, is a derivative of mono-carbonyl analogues of curcumin (MACs). The molecule has an E conformation for each of the olefinic bonds. The 1-propylpiperidin-4-one ring has a distorted chair conformation with the ring N and the C and O atoms of the carbonyl group deviating from the mean plane of the remaining four ring C atoms by 0.682?(2), ?0.134?(3) and ?0.340?(4)?, respectively. The dihedral angle between the benzene rings is 26.5?(1). In the crystal, molecules are connected by weak CH?O and CH?? interactions.

Yang, Quanzhi; Chen, Lingzi; Weng, Bixia; Fan, Lei; Wu, Xiaoping

2013-01-01

161

Transcriptome analysis provides new insights into liver changes induced in the rat upon dietary administration of the food additives butylated hydroxytoluene, curcumin, propyl gallate and thiabendazole  

Microsoft Academic Search

Transcriptomics was performed to gain insight into mechanisms of food additives butylated hydroxytoluene (BHT), curcumin (CC), propyl gallate (PG), and thiabendazole (TB), additives for which interactions in the liver can not be excluded. Additives were administered in diets for 28 days to SpragueDawley rats and cDNA microarray experiments were performed on hepatic RNA. BHT induced changes in the expression of

Rob Stierum; Ana Conesa; Wilbert Heijne; Ben van Ommen; Karin Junker; Mary P. Scott; Roger J. Price; Clive Meredith; Brian G. Lake; John Groten

2008-01-01

162

THE EFFECT OF THE ANTIOXIDANTS, BUTYLATED HYDROXY ANISOLE, BUTYLATED HYDROXY TOLUENE AND PROPYL GALLATE ON GROWTH, LIVER AND SERUM LIPIDS AND SERUM SODIUM LEVELS OF THE RAT  

Microsoft Academic Search

Confirmation of our previous finding that there are greater hazards in the use of butylated hydroxy toluene (BHT) than in that of butylated hydroxy anisole (BHA) as antioxidants for use in human foodstuffs was obtained. BHA and propyl gallate (PG) met one of the requirements for safety as a food additive. A sex difference in the effect of BHT was

AR Johnson; FR Hewgill

1961-01-01

163

Anti-HSV-1 and anti-HIV-1 activity of gallic acid and pentyl gallate  

Microsoft Academic Search

The synthetic n-alkyl esters of gallic acid (GA), also known as gallates, especially propyl, octyl and dodecyl gal- lates, are widely employed as antioxidants by food and pharmaceutical industries. The inhibitory effects of GA and 15 gallates on Herpes Simplex Virus type 1 (HSV-1) and Human Immunodeficiency Virus (HIV-1) replication were investigated here. After a preliminary screening of these compounds,

Jadel Mller Kratz; Carla Regina Andrighetti-Frhner; Deise Juliana Kolling; Paulo Csar Leal; Cludio Csar Cirne-Santos; Rosendo Augusto Yunes; Ricardo Jos Nunes; Edward Trybala; Tomas Bergstrm; Izabel CPP Frugulhetti; Clia Regina Monte Barardi; Cludia Maria Oliveira Simes

2008-01-01

164

Ionic liquid-regulated sulfamic acid: chemoselective catalyst for the transesterification of ?-ketoesters  

Microsoft Academic Search

1-Propyl-3-methylimidazolium chloride ([C3MIm]Cl) ionic liquid and sulfamic acid (NH2SO3H), as a synergetic catalytic medium, were used for the transesterification of acetoacetate with alcohols of different structures. It shows the good ability for the chemoselective transesterificatin of ?-ketoesters and maintains its catalytic activity in the reuse.

Wang Bo; Yang Li Ming; Suo Ji Shuan

2003-01-01

165

Synthesis, gastroprotective, antisecretory and anti-Helicobacter effect of N-[3-(3-(1-piperidinylmethyl) phenoxy)propyl]-hydroxyacetamide 2-hydroxypropane-1,2,3-tricarboxylate bismuth (3+) complex (MX1)-MX1.  

PubMed

MX1 (N-[3-(3-(1-piperidinylmethyl)phenoxy)propyl]-hydroxyacetamide+ ++ 2-hydroxypropane-1,2,3-tricarboxylate bismuth (3+) complex) is a novel salt of the active metabolite of H2-antagonist roxatidine with a complex of bismuth with citric acid. In a model of ethanol-induced ulcers in male Wistar rats, both roxatidine and the bismuth salt reduced the number and the total length of lesions. Comparison of roxatidine and MX1 at equimolar doses of 160 mumol kg-1 showed a more potent cytoprotective effect of MX1. The potency of anti-secretory and antiacidic effects of MX1 was more than twice that of roxatidine on histamine-stimulated secretion in female Wistar pylorus-ligated rats. Microbiological tests with the reference bismuth preparation De-Nol showed prominent anti-Helicobacter properties of MX1 in-vitro. Both test compounds had similar range of MICs to Helicobacter pylori, from 4 to 64 microgram bismuth mL-1. The cytoprotective, antisecretory, anti-acidic and anti-Helicobacter properties of the new agent MX1 warrant further more extensive pharmacological and clinical trials. PMID:8737057

Ivanov, C; Petkov, O; Petrov, P; Taskov, M; Athanassova, R; Tsvetkova, E; Kotsev, V; Lyutakov, G; Nikolov, G; Savov, E

1996-03-01

166

Fast Esterification of Acetic Acid with Short Chain Alcohols in Microchannel Reactor  

Microsoft Academic Search

Microchannel reactor was used for the fast synthesis of acetic acid esters, including methyl acetate, ethyl acetate, n-propyl acetate and n-butyl acetate. Effects of the inner diameter of microchannel reactors, dosage of catalyst, residence time, reaction temperature\\u000a and molar ratio of alcohol to acetic acid on yields of esters were studied in the p-toluene sulfonic acid-catalyzed homogeneous esterification of acetic

Xingjun Yao; Jianfeng Yao; Lixiong Zhang; Nanping Xu

2009-01-01

167

Diesters from Oleic Acid: Synthesis, Low Temperature Properties, and Oxidation Stability  

Microsoft Academic Search

Several diesters were prepared from commercially available oleic acid and common organic acids. The key step in the three\\u000a step synthesis of oleochemical diesters entails a ring opening esterification of alkyl 9,10-epoxyoctadecanoates (alkyl: propyl,\\u000a isopropyl, octyl, 2-ethylhexyl) using propionic and octanoic acids without the need for either solvent or catalyst. Each synthetic\\u000a diester was evaluated for both low temperature operability

Bryan R. Moser; Brajendra K. Sharma; Kenneth M. Doll; Sevim Z. Erhan

2007-01-01

168

Synthesis of N-phenyl-N-(3-(piperidin-1-yl)propyl)benzofuran-2-carboxamides as new selective ligands for sigma receptors.  

PubMed

Novel benzofuran-2-carboxamide ligands, which are selective for sigma receptors, have been synthesized via a microwave-assisted Perkin rearrangement reaction and a modified Finkelstein halogen-exchange used to facilitate N-alkylation. The ligands synthesized are the 3-methyl-N-phenyl-N-(3-(piperidin-1-yl)propyl)benzofuran-2-carboxamides (KSCM-1, KSCM-5 and KSCM-11). The benzofuran-2-carboxamide structure was N-arylated and N-alkylated to include both N-phenyl and N-(3-(piperidin-1-yl)propyl substituents, respectively. These new carboxamides exhibit high affinity at the sigma-1 receptor with K(i) values ranging from 7.8 to 34nM. Ligand KSCM-1 with two methoxy substituents at C-5 and C-6 of the benzofuran ring, and K(i)=27.5nM at sigma-1 was found to be more selective for sigma-1 over sigma-2. PMID:23084435

Marriott, Karla-Sue C; Morrison, Andrew Z; Moore, Misty; Olubajo, Olarongbe; Stewart, Leonard E

2012-09-29

169

Synthesis, adsorption and selectivity studies of N-propyl quaternized magnetic poly(4-vinylpyridine) for hexavalent chromium.  

PubMed

The ability of solid N-propyl quaternized magnetic poly(4-vinylpyridine) for the extraction of chromium(VI) in aqueous solutions was investigated. For the synthesized Cr(VI) magnetic polymers, the optimum pH obtained was 4 for both the magnetic ion imprinted polymer (IIP) and the corresponding non-ion imprinted polymer NIP. The amount of the adsorbent which gave the maximum adsorption was determined to be 20 and 65mg for the magnetic IIP and NIP, respectively. A Cr(VI) concentration which was adsorbed maximally was 5mgL(-1) which was therefore taken as the optimum. The maximum adsorption capacities for the magnetic polymers were 6.20 and 1.87mgg(-1) for the magnetic IIP and NIP, respectively. The optimum time for the adsorption of the Cr(VI) analyte was determined as 40min. The prepared magnetic ion imprinted polymer showed good selectivity towards Cr(VI). The order of selectivity of the investigated anions followed the sequence: Cr2O7(2-)>SO4(2-)>F(-)>NO3(-). PMID:24148460

Tavengwa, Nikita Tawanda; Cukrowska, Ewa; Chimuka, Luke

2013-07-30

170

Stability of the complex BSA-6-propyl-2-thiouracil in the presence of GuHCl and urea  

NASA Astrophysics Data System (ADS)

Pathologic structure of albumin is present in blood of uremic or diabetic patients. The defective binding of albumin can cause, among others, inhibition of the metabolism of amphipathic hormones and the enhancement of the toxicity of drugs. We aim to show the alteration of the binding site of 6-propyl-2-thiouracil (PTU) in bovine serum albumin (BSA) in the presence of urea and guanidine hydrochloride. This study shows that PTU has the tendency to interact within the hydrophobic domain IIA or IB of serum albumin and to quench the fluorescence of tryptophanyl side chains by the static and collisional quenching mechanism. For the binding to the native protein, two classes of binding sites are seen. In the first one, the binding constant is equal to KbI-9.6104 M-1, and in the second class, the binding constant is KbII-7.1103 M-1. For the binding to the denaturated serum albumin, only one class of the binding sites can be observed. The binding constants for BSA denatured with urea and GuHCl are lower and are equal to 2.2104 M-1 and 3.5104 M-1, respectively. Evaluation of the binding ability of serum albumin is also important in case of older people because weaker drug protein interaction can result in the increase of drug concentration in the blood serum.

Rwnicka, Joanna; Su?kowska, Anna; Po?ycka, Jadwiga; Bojko, Barbara; Su?kowski, Wies?aw W.

2006-07-01

171

Fate of pyribambenz propyl (ZJ0273) in anaerobic soils revealed by position-specific 14C labeling.  

PubMed

Pyribambenz propyl, or ZJ0273, is a new and widely used pyrimidynyloxybenzoic herbicide; however, its behavior and safety in anaerobic soils remain poorly understood. In this study, ZJ0273 was labeled with (14)C on its benzoate-, pyrimidyl- and benzyl- rings respectively, and applied to anoxic flooding soils to characterize its anaerobic fates. Over the 100 d incubation, the amended (14)C-ZJ0273 was slightly mineralized to (14)CO2 (<4%) or redistributed into the overlaying water (<10%), with the majority of the (14)C (82-98%) remaining in the soil. The residues in soil underwent a gradual transformation from extractable residues (ER) to bound residues (BR), with the percentage of (14)C-BR increasing from 1.1 to 2.5% at day 5 to 23.2-47.2% at day 100. The proportion of (14)C-ER, (14)C-BR and (14)CO2 depended both on the soil property and the labeling position. Generally, ZJ0273 has the highest tendency to form BR in fluvio-marine yellow loamy soil, and the mineralization on both the benzoate and benzyl rings tends to be more extensive in red-clayed soil than the other soils. The ring-specific labeling (14)C on three aromatic rings respectively provides full molecular information and yield information on sub-molecular level, i.e., the benzoate ring was generally more susceptible to cleavage than the pyrimidyl or benzyl rings (P<0.01). PMID:23728078

Wang, Wei; Yue, Long; Zhang, Sufen; Ye, Qingfu; Qi, Wenyuan; Wang, Haiyan; Chen, Ziyuan

2013-05-02

172

Psychotomimetic opiate receptors labeled and visualized with (+)-(/sup 3/H)3-(3-hydroxyphenyl)-N-(1-propyl)piperidine  

SciTech Connect

3-(3-Hydroxyphenyl)-N-(1-propyl)piperidine (3-PPP) has been proposed as a selective dopamine autoreceptor agonist in the central nervous system. This report describes the pharmacology and localization of specific high-affinity binding sites for (+)-(/sup 3/H)3-PPP in brain. The drug specificity of (+)-(/sup 3/H)3-PPP binding is identical to that of sigma receptors, which may mediate psychotomimetic effects of some opiates. Haloperidol and the opioid derivatives, pentazocine, cyclazocine, and SKF 10,047 are potent inhibitors of (+)-(/sup 3/H)3-PPP binding. Stereoselectivity is exhibited for the (+) isomers of cyclazocine and SKF 10.047 at the sigma site, opposite to the stereoselectivity seen at ..mu.., sigma, and k opiate receptors. (+)-(/sup 3/H)3-PPP does not label dopamine receptors, as potent dopamine agonists and antagonists are weak inhibitors of binding and the localization of specific (+)-(/sup 3/H)3-PPP binding sites does not parallel that of dopamine neurons. Discrete localizations of (+)-(/sup 3/H)3-PPP binding sites in many brain areas including limbic, midbrain, brainstem, and cerebellar regions may explain psychotomimetic actions of opiates and behavior effects of 3-PPP. 41 references, 2 figures, 1 table.

Largent, B.L.; Gundlach, A.L.; Snyder, S.H.

1984-08-01

173

Highly efficient non-biofouling coating of zwitterionic polymers: poly((3-(methacryloylamino)propyl)-dimethyl(3-sulfopropyl)ammonium hydroxide).  

PubMed

This work describes the formation of highly efficient non-biofouling polymeric thin films of poly((3-(methacryloylamino)propyl)-dimethyl(3-sulfopropyl)ammonium hydroxide), (poly(MPDSAH)). The poly(MPDSAH) films were generated from the self-assembled monolayers terminating in an initiator of atom transfer radical polymerization (ATRP) by the surface-initiated ATRP of MPDSAH. The poly(MPDSAH) films on a gold surface were characterized by ellipsometry, FT-IR spectroscopy, contact angle goniometery, and X-ray photoelectron spectroscopy. The copper complexes and unpolymerized monomers trapped inside the polymer brushes were completely washed out by soaking the poly(MPDSAH)-coated substrate in water at 40 degrees C for 4 days. The amount of proteins nonspecifically adsorbed onto the poly(MPDSAH) films was evaluated by surface plasmon resonance spectroscopy: the adsorption of proteins was <0.6 ng/cm(2) on the surfaces for all the model proteins. The ability of the poly(MPDSAH) films to resist the nonspecific adsorption of proteins was comparable to that of the best known systems. PMID:17432887

Cho, Woo Kyung; Kong, Bokyung; Choi, Insung S

2007-04-14

174

Protective effect of s-allyl cysteine and s-propyl cysteine on acetaminophen-induced hepatotoxicity in mice.  

PubMed

In vivo protective effects of s-allyl cysteine (SAC) and s-propyl cysteine (SPC) against acetaminophen-induced hepatotoxicity in Balb/cA mice were studied. SAC and SPC at 1g/L were added into drinking water for four weeks and followed by acetaminophen treatment. Acetaminophen treatment significantly depleted glutathione content, increased oxidation stress and elevated alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities (P < 0.05); however, the intake of SAC or SPC significantly alleviated glutathione depletion and the elevation of ALT and AST, enhanced glutathione peroxidase activity, and lowered malondialdehyde formation (P < 0.05). Plasma levels of C-reactive protein (CRP), von Willebrand factor (vWF), IL-6, IL-10 and TNF-alpha were significantly increased by acetaminophen treatment (P < 0.05); and SAC or SPC intake significantly suppressed acetaminophen-induced elevation of CRP, vWF and the three cytokines (P < 0.05). Acetaminophen treatment also significantly increased plasminogen activator inhibitor-1 (PAI-1) activity and plasma fibrinogen level, and decreased antithrombin III (AT-III) and protein C activities (P < 0.05). SAC or SPC intake alleviated AT-III and protein C reduction (P < 0.05); but did not affect PAI-1 activity and plasma fibrinogen level (P > 0.05). These data suggest that SAC and SPC are potential multiple-protective agents against acetaminophen-induced hepatotoxicity. PMID:16181716

Hsu, Cheng-Chin; Lin, Chun-Che; Liao, Ting-Sin; Yin, Mei-Chin

2005-09-21

175

Product study of the OH, NO3, and O3 initiated atmospheric photooxidation of propyl vinyl ether.  

PubMed

A product study is reported on the gas-phase reactions of OH and NO3 radicals and ozone with propyl vinyl ether (PVE). The experiments were performed in a 405 L borosilicate glass chamber in synthetic air at 298 +/- 3 K using long path in situ FTIR spectroscopy for the analysis of the reactants and products. In the presence of NO(x) (NO + NO2) the main products for the OH-radical initiated oxidation of PVE were propylformate and formaldehyde with molar formation yields of 78.6 +/- 8.8% and 75.9 +/- 8.4%, respectively. In the absence of NO(x) propylformate and formaldehyde were formed with molar formation yields of 63.0 +/- 9.0% and 61.3 +/- 6.3%, respectively. In the reaction of NO3 radicals with PVE propylformate 52.7 +/- 5.9% and formaldehyde 55.0 +/- 6.3% were again observed as major products. The ozonolysis of PVE led to the production of propylformate, formaldehyde, hydroxyperoxymethyl formate (HPMF; HC(O)OCH2OOH), and CO with molar formation yields of 89.0 +/- 11.4%, 12.9 +/- 4.0%, 13.0 +/- 3.4%, and 10.9 +/- 2.6%, respectively. The formation yield of OH radicals in the ozonolysis of PVE was estimated to be 17 +/- 9%. Simple atmospheric degradation mechanisms are postulated to explain the formation of the observed products. PMID:16999119

Zhou, Shouming; Barnes, Ian; Zhu, Tong; Klotz, Bjrn; Albu, Mihaela; Bejan, Iustinian; Benter, Thorsten

2006-09-01

176

Over-expression of GAPDH in human colorectal carcinoma as a preferred target of 3-bromopyruvate propyl ester.  

PubMed

It has long been observed that many cancer cells exhibit increased aerobic glycolysis and rely more on this pathway to generate ATP and metabolic intermediates for cell proliferation. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a key enzyme in glycolysis and has been known as a housekeeping molecule. In the present study, we found that GAPDH expression was significantly up-regulated in human colorectal carcinoma tissues compared to the adjacent normal tissues, and also increased in colon cancer cell lines compared to the non-tumor colon mucosa cells in culture. The expression of GAPDH was further elevated in the liver metastatic tissues compared to the original colon cancer tissue of the same patients, suggesting that high expression of GAPDH might play an important role in colon cancer development and metastasis. Importantly, we found that 3-bromopyruvate propyl ester (3-BrOP) preferentially inhibited GAPDH and exhibited potent activity in inducing colon cancer cell death by causing severe depletion of ATP. 3-BrOP at low concentrations (1-10 ?M) inhibited GAPDH and a much higher concentration (300 ?M) was required to inhibit hexokinase-2. The cytotoxic effect of 3-BrOP was associated with its inhibition of GAPDH, and colon cancer cells with loss of p53 were more sensitive to this compound. Our study suggests that GAPDH may be a potential target for colon cancer therapy. PMID:22350014

Tang, Zhenjie; Yuan, Shuqiang; Hu, Yumin; Zhang, Hui; Wu, Wenjing; Zeng, Zhaolei; Yang, Jing; Yun, Jingping; Xu, Ruihua; Huang, Peng

2012-02-18

177

Thermodynamic study on binary mixtures of propyl ethanoate and an alkan-1-ol (C 2C 4). Isobaric vaporliquid equilibria and excess properties  

Microsoft Academic Search

This paper presents an analysis on binary mixtures of propyl ethanoate and an alkan-1-ol (ethanol to butanol) using the results obtained for different thermodynamic quantities such as the isobaric vaporliquid equilibrium (VLE) data at pressures of 101.3 kPa and 160.0 kPa, excess enthalpies and excess volumes. Vapor pressures for the same normal alkanols used, determined using the same equilibrium still,

Juan Ortega; Carmelo Gonzalez; Juan Pea; Salvador Galvn

2000-01-01

178

Effect of a hydrophobic interaction in the reaction of S-(?-alkylthioethyl) O-propyl methylphosphonothionates and their methyl methosulfates with cholinesterases of warm-blooded animals  

Microsoft Academic Search

The action of S-(?-alkylthioethyl) O-propyl methylphosphonates and their methyl methosulfates with different lengths of the\\u000a S-alkyl radical on the enzymatic activity of acetylcholinesterase from human blood erythrocytes and butyrylcholinesterase\\u000a from horse blood serum has been investigated. The existence of a hydrophobic interaction on the sorption of inhibitors in\\u000a the active site of the enzymes has been established. For the enzymes

M. Gulyamov; Z. Tilyabaev; D. N. Dalimov; A. A. Abduvakhabov

1987-01-01

179

Long-term stability of cell micropatterns on poly((3-(methacryloylamino)propyl)-dimethyl(3-sulfopropyl)ammonium hydroxide)-patterned silicon oxide surfaces  

Microsoft Academic Search

In this work, we compared the long-term stability and integrity of cell patterns on newly reported, zwitterionic poly((3-(methacryloylamino)propyl)dimethyl(3-sulfopropyl)ammonium hydroxide) (poly(MPDSAH)) films with those on widely used, poly(poly(ethylene glycol) methyl ether methacrylate) (poly(PEGMEMA)) ones. The micropatterns of both polymers were formed on a silicon oxide surface by a combination of micropattern generation of a photoresist, vapor deposition of a silane-based polymerization

Woo Kyung Cho; Bokyung Kong; Hyung Ju Park; Jinkyu Kim; Won Chegal; Joon Sig Choi; Insung S. Choi

2010-01-01

180

Swellable molecularly imprinted poly N-( N-propyl)acrylamide particles for detection of emerging organic contaminants using surface plasmon resonance spectroscopy  

Microsoft Academic Search

Lightly crosslinked theophylline imprinted polyN-(N-propyl)acrylamide particles (ca. 300nm in diameter) that are designed to swell and shrink as a function of analyte concentration in aqueous media were spin coated onto a gold surface. The nanospheres responded selectively to the targeted analyte due to molecular imprinting. Chemical sensing was based on changes in the refractive index of the imprinted particles that

Barry K. Lavine; David J. Westover; Necati Kaval; Nikhil Mirjankar; Leah Oxenford; George K. Mwangi

2007-01-01

181

Role of brain dopaminergic mechanisms in rodent aggressive behavior: Influence of () N-n -propyl-norapomorphine on three experimental models  

Microsoft Academic Search

()N-n-Propyl-norapomorphine (NPA), a potent agonist of brain dopamine receptors, influences aggressive behavior, but the type of influence depends on the experimental conditions. In rats, NPA increases aggression elicited by electrical foot shock, but decreases predatory aggression against turtles as well as isolation-induced aggression in male mice. NPA proves more potent than apomorphine in both the foot shock and predatory test.

G. Baggio; F. Ferrari

1980-01-01

182

The effect of novel [3-fluoro-(2-phosphonoethoxy)propyl]purines on the inhibition of Plasmodium falciparum, Plasmodium vivax and human hypoxanthine-guanine-(xanthine) phosphoribosyltransferases.  

PubMed

Protozoan parasites from the Plasmodiidae family are the causative agents of malaria. Inhibition of hypoxanthine-guanine-(xanthine) phosphoribosyltransferase (HG(X)PRT) has been suggested as a target for development of new anti-malarial therapeutics. Acyclic nucleoside phosphonates (ANPs) are potent and selective inhibitors of plasmodial HG(X)PRTs. A new series of ANPs, based on the chemical structure and inhibitory activity of three ANPs, 2-(phosphonoethoxy)ethyl with either guanine or hypoxanthine as the base (PEEG and PEEHx) and 3-hydroxy-2-(phosphonomethoxy)propyl with guanine as the base (HPMPG), were prepared. These compounds are stereoisomers of 3-fluoro-(2-phosphonoethoxy)propyl (FPEPs) and 3-fluoro-(2-phosphonomethoxy)propyl (FPMPs) analogues. Both the (R)- and (S)-isomers of these fluorinated derivatives have higher Ki values (by 10- to 1000-fold) for human HGPRT and Plasmodium falciparum HGXPRT than the non-fluorinated ANPs. Possible explanations for these changes in affinity are proposed based on docking studies using the known crystal structures of human HGPRT in complex with PEEG. PMID:23850568

Baszczy?ski, Ond?ej; Hockov, Dana; Janeba, Zlatko; Hol, Antonn; Jansa, Petr; Dra?nsk, Martin; Keough, Dianne T; Guddat, Luke W

2013-06-22

183

SYNTHESIS AND ANTIVIRAL EVALUATION OF 9-(S)-[3-ALKOXY-2-(PHOSPHONOMETHOXY)PROPYL]NUCLEOSIDE ALKOXYALKYL ESTERS: INHIBITORS OF HEPATITIS C VIRUS AND HIV-1 REPLICATION  

PubMed Central

We reported previously that octadecyloxyethyl 9-(S)-[3-hydroxy-2-(phosphonomethoxy)-propyl]adenine (ODE-(S)-HPMPA) was active against genotype 1b and 2a hepatitis C virus (HCV) replicons. This is surprising because acyclic nucleoside phosphonates have been regarded as having antiviral activity only against double stranded DNA viruses, HIV and HBV. We synthesized octadecyloxyethyl 9-(S)-[3-methoxy-2-(phosphonomethoxy)propyl]-adenine and found it to be active in genotype 1b and 2a HCV replicons with EC50 values of 1-2 ?M and a CC50 of>150 ?M. Analogs with substitutions at the 3?-hydroxyl larger than methyl or ethyl, or with other purine bases were less active but most compounds had significant antiviral activity against HIV-1 in vitro. The most active anti-HIV compound was octadecyloxyethyl 9-(R)-[3-methoxy-2-(phosphonomethoxy)propyl]guanine with an EC50 <0.01 nanomolar and a selectivity index of>4.4 million.

Valiaeva, Nadejda; Wyles, David L.; Schooley, Robert T.; Hwu, Julia B.; Beadle, James R.; Prichard, Mark N.

2011-01-01

184

Inhibition of Ethylene Biosynthesis by Salicylic Acid  

PubMed Central

Salicylic acid inhibited ethylene formation from ACC in self-buffered (pH 3.8) pear (Pyrus communis) cell suspension cultures with a K1app of about 10 micromolar after 1 to 3 hours incubation. Inhibition appeared noncompetitive. Among 22 related phenolic compounds tested, only acetylsalicylic acid showed similar levels of inhibition. Inhibition by salicylic acid was inversely dependent on the pH of the culture medium and did not require a continuous external supply of salicylate. When compared to known inhibitors of the ethylene forming enzyme, cobalt, n-propyl gallate, and dinitrophenol, inhibition by salicylic acid most closely resembled that by dinitrophenol but salicylic acid did not produce the same degree of respiratory stimulation. Results are discussed in terms of other known effects of salicylic acid on plants, pH-dependency, and the possible influence of salicylic acid on electron transport.

Leslie, Charles A.; Romani, Roger J.

1988-01-01

185

[Lipase-catalyzed production of biodiesel from high acid value waste oil with ultrasonic assistant].  

PubMed

Biodiesel fuel produced with the enzyme-catalyzed esterification and transesterification of high acid value waste oil through ultrasonic assistant was explored. Propyl oleate, biodiesel, converted from high acid value waste oil and 1-proponal catalyzed with immobilized lipases from Candida antarctica and Aspergillus oryzae in conditions of ultrasonic assistant. Commercial immobilized lipase Novozym 435 from C. antarctica was used as biocatalyst catalyzing high acid value waste oil and 1-proponal esterification and transesterification to propyl oleate under the ultrasonic assistant conditions and different conditions such as lipases amounts, initiatory molar ratio of propanol to oil, frequency of ultrasonic and power of ultrasonic were investigated and optimized. It is revealed that the enzymatic activity of Novozym435 is enhanced and, in particular, enzyme-catalyzed transesterification activity is enhanced obviously under the ultrasonic assistant conditions. Low frequency and mild energy ultrasonic is a key factor for enhancing enzymatic activity, emulsifying oil-propanol system and accelerating the speed of produce diffusing in the system. Under the optimal ultrasonic assistant reaction conditions, such as Novozym435 amounts 8% by oil quantity, initiatory molar ratio of propanol to oil 3:1, frequency of ultrasonic 28 KHz, power of ultrasonic 100 W and temperature of water batch 40-45 degrees C, the conversion ratio to propyl oleate reached to 94.86% in 50 mins in comparison with the highest conversion ratio to propyl oleate 84.43% under the conventional mechanical agitation conditions. Furthermore, it is demonstrated that various short chain linear and branched alcohols (C1-C5) show high conversion ratio to fatty acid alkyl esters (biodiesel) under the optimal ultrasonic assistant reaction conditions. On the other hand, ultrasonic energy is propitious to reduce the adsorption of product propyl oleate, by-product glycerol and other emplastics in system on the surface of immobilized lipase Novzym435 and recyclable Novozym435 possess clean appearances, well decentralizations, no agglomeration and easy washing and well operational stability. PMID:18257248

Wang, Jian-Xun; Huang, Qing-De; Huang, Feng-Hong; Wang, Jiang-Wei; Huang, Qin-Jie

2007-11-01

186

Immobilized hyaluronic acid containing model silicone hydrogels reduce protein adsorption  

Microsoft Academic Search

The physical immobilization of hyaluronic acid (HA) as a wetting agent in contact lens applications was investigated using model silicone hydrogels prepared by co-polymerizing methacryloxy propyl tris (trimethylsiloxy) silane (Tris) and hydroxyethylmethacrylate (HEMA). Two different molecular weights of HA were investigated, as well as various Tris\\/HEMA ratios. Cross-linked HA, while only present in small amounts, increased water uptake and hydrophilicity

Mark van Beek; Andrea Weeks; Heather Sheardown

2008-01-01

187

The ozone productivity of n-propyl bromide: Part 2--An exception to the Maximum Incremental Reactivity Scale.  

PubMed

In an earlier paper the ozone-forming potential of n-propyl bromide (NPB) was studied with a new methodology designed to address issues associated with a marginal smog-forming compound. However, the U.S. Environmental Protection Agency (EPA) subsequently revised its policy and now recommends using the Maximum Incremental Reactivity (MIR) scale to rank the ozone-forming potential of all volatile organic compounds (VOCs), including those of marginal ozone productivity. Nevertheless, EPA contemplated exceptions to the box-model-derived MIR scale by allowing use of photochemical grid-model simulations for case specific reactivity assessments. The California Air Resources Board (CARB) also uses the MIR scale and CARB has a Reactivity Scientific Advisory Committee that can consider exceptions to the MIR scale. In this study, grid-model simulations that were recommended by EPA are used to evaluate the incremental ozone impacts of NPB using an update to the chemical mechanism developed in an earlier paper. New methods of analysis of the grid-model output are further developed here to quantify the relative reactivities between NPB and ethane over a wide range of conditions. The new grid-model-based analyses show that NPB is significantly different and generally less in ozone-forming potential (i.e., reactivity) than predicted by the box-model-based MIR scale relative to ethane, EPA's "bright-line" test for non-VOC status. Although NPB has low reactivity compared to typical VOCs on any scale, the new grid-model analyses developed here show that NPB is far less reactive (and even has negative reactivity) compared to the reactivity predicted by the MIR scale. PMID:18672713

Whitten, Gary Z; Yarwood, Greg

2008-07-01

188

Antidepressant Potential of 5-HT3 Receptor Antagonist, N-n- propyl-3-ethoxyquinoxaline-2-carboxamide (6n)  

PubMed Central

The present study was designed to evaluate the antidepressant potential of 5-HT3 receptor antagonist N-n-propyl-3-ethoxyquinoxaline-2-carboxamide (6n). The compound 6n with optimum log P and pA2 value identified from a series of compounds synthesized in our laboratory was subjected to forced Swim Test (FST) (1, 2, and 4 mg/kg, i.p) and Tail Suspension Test (TST) (1, 2, and 4 mg/kg, i.p.). The compound 6n significantly reduced the duration of immobility in mice without affecting the baseline locomotion. Moreover, 6n (2 mg/kg, i.p.) potentiated the 5-hydroxytryptophan (5-HTP)-induced head twitch responses in mice and 6n at tested dose (1 and 2 mg/kg, i.p.) reversed the reserpine-induced hypothermia in rats. In interaction studies of 6n with various standard drugs/ligands using FST, 6n (1 mg/kg, i.p.) potentiated the antidepressant effect of venlafaxine (4 and 8 mg/kg, i.p.) and fluoxetine (10 and 20 mg/kg, i.p.). Additionally, 6n (1 and 2 mg/kg, i.p.) influenced the effect of harmane (5 mg/ kg, i.p.) as well as reversed the effect of parthenolide (1 mg/kg, i.p.) by reducing the duration of immobility in FST. Furthermore, 6n (1 mg/kg, i.p.) potentiated the effect of bupropion (10 and 20 mg/kg, i.p.) in TST. Chronic 6n (1 and 2 mg/kg, i.p.) treatment attenuated the behavioral abnormalities in olfactory bulbectomized rats. In conclusion, these various findings reiterated the antidepressant-like effects of 6n in behavioral models of depression.

Mahesh, R; Bhatt, S; Devadoss, T; Jindal, AK; Gautam, BK; Pandey, DK

2012-01-01

189

Antidepressant Potential of 5-HT3 Receptor Antagonist, N-n- propyl-3-ethoxyquinoxaline-2-carboxamide (6n).  

PubMed

The present study was designed to evaluate the antidepressant potential of 5-HT3 receptor antagonist N-n-propyl-3-ethoxyquinoxaline-2-carboxamide (6n). The compound '6n' with optimum log P and pA 2 value identified from a series of compounds synthesized in our laboratory was subjected to forced Swim Test (FST) (1, 2, and 4 mg/kg, i.p) and Tail Suspension Test (TST) (1, 2, and 4 mg/kg, i.p.). The compound '6n' significantly reduced the duration of immobility in mice without affecting the baseline locomotion. Moreover, '6n' (2 mg/kg, i.p.) potentiated the 5-hydroxytryptophan (5-HTP)-induced head twitch responses in mice and '6n' at tested dose (1 and 2 mg/kg, i.p.) reversed the reserpine-induced hypothermia in rats. In interaction studies of '6n' with various standard drugs/ligands using FST, '6n' (1 mg/kg, i.p.) potentiated the antidepressant effect of venlafaxine (4 and 8 mg/kg, i.p.) and fluoxetine (10 and 20 mg/kg, i.p.). Additionally, '6n' (1 and 2 mg/kg, i.p.) influenced the effect of harmane (5 mg/ kg, i.p.) as well as reversed the effect of parthenolide (1 mg/kg, i.p.) by reducing the duration of immobility in FST. Furthermore, '6n' (1 mg/kg, i.p.) potentiated the effect of bupropion (10 and 20 mg/kg, i.p.) in TST. Chronic '6n' (1 and 2 mg/kg, i.p.) treatment attenuated the behavioral abnormalities in olfactory bulbectomized rats. In conclusion, these various findings reiterated the antidepressant-like effects of '6n' in behavioral models of depression. PMID:23493308

Mahesh, R; Bhatt, S; Devadoss, T; Jindal, Ak; Gautam, Bk; Pandey, Dk

2012-10-01

190

Hydrolytic enzymes production by Aspergillus section Nigri in presence of butylated hydroxyanisole and propyl paraben on peanut meal extract agar.  

PubMed

BACKGROUND: In the last years, food grade antioxidants are used safely as alternatives at traditional fungicides to control fungal growth in several food and agricultural products. AIMS: In this work, the effect of butylated hydroxyanisole (BHA) and propyl paraben (PP) on two hydrolytic enzyme activity (?-d-glucosidase and ?-d-galactosidase) by Aspergillus section Nigri species under different water activity conditions (aW; 0.98, 0.95 and 0.93) and incubation time intervals (24, 48, 72 and 96h) was evaluated on peanut-based medium. METHODS: The activity of two glycosidases, ?-d-glucosidase and ?-d-galactosidase, was assayed using as substrates 4-nitrophenyl-?-d-glucopyranosido and 4-nitrophenyl-?-d-galactopyranosido, respectively. The enzyme activity was determined by the increase in optical density at 405nm caused by the liberation of p-nitrophenol by enzymatic hydrolysis of the substrate. Enzyme activity was expressed as micromoles of p-nitrophenol released per minute. RESULTS: The major inhibition in ?-d-glucosidase activity of A. carbonarius and A. niger was found with 20mmoll(-1) of BHA or PP at 0.98 and 0.95 aW, respectively, whereas for ?-d-galactosidase activity a significant decrease in enzyme activity with respect to control was observed in A. carbonarius among 5 to 20mmoll(-1) of BHA or PP in all conditions assayed. Regarding A. niger, the highest percentages of enzyme inhibition activity were found with 20mmoll(-1) of BHA or PP at 0.95 aW and 96h. CONCLUSIONS: The results of this work provide information about the capacity of BHA and PP to inhibit in vitro conditions two of the most important hydrolytic enzymes produced by A. carbonarius and A. niger species. PMID:23583262

Barberis, Carla L; Landa, Mara F; Barberis, Mauricio G; Giaj-Merlera, Guillermo; Dalcero, Ana M; Magnoli, Carina E

2013-04-11

191

Morphology and water resistance of mixed silane films of bis[3-(triethoxysilyl) propyl]tetrasulfide and bis-[trimethoxysilylpropyl]amine  

SciTech Connect

Functional organosilanes are powerful interface-active agents that find applications as adhesion promoters as well as optical, dielectric and protective coatings. Bis-silanes are of particular interest because they are highly crosslinked leading to very robust films. In almost all applications, the water resistance of the films is a critical performance measure. Here we use neutron reflectivity to address the effect of bridging group on the hydrothermal response of bis-silane films prepared using bis[3-(triethoxysilyl) propyl]tetrasulfide and bis-[trimethoxysilylpropyl]amine. Neat and mixed films are examined as-prepared, after exposure to water vapor and then in the re-dried state. The bridging group is the key factor that controls the morphology and water resistance of silane films. Although bis-sulfur silane is not as condensed as bis-amino silane, bis-sulfur swells less in water because of the hydrophobic nature of bridging group. The reflectivity of bis-sulfur silane film is reversible after room-temperature water conditioning but not at 80 C, indicating chemical alternation of the film at 80 C. The water resistance of mixed silane is roughly that of both components weighted by their volume fraction. But based on the enhanced shrinkage that occurs following water-vapor conditioning of the mixed film, condensation is accelerated in the mixed silane. Regarding the precursor solution, bis-amino silane may act as a catalyst in the hydrolysis of bis-sulfur silane leading to more silanols in the solution and further condensation in the film. Variation in the structure normal to the substrate is also examined by swelling the film with d-nitrobenzene, a non-reacting swelling agent.

Pan, Guirong; Schaefer, Dale W.; van Ooij, Wim J.; Kent, Michael S.; Majewski, Jaroslaw; Yim, Hyun (UCIN); (Sandia); (LANL)

2010-12-03

192

Effect of antithyroid agents 6-propyl-2-thiouracil and 1-mehtyl-2-mercaptoimidazole on human thyroid iodine peroxidase.  

PubMed

The mechanism of inhibition of human thyroid iodide peroxidase (TPO) by 6-propyl-2-thiouracil (PTU) and 1-methyl-2-mercaptoimidazole (MMI) used in the therapy of hyperthyroid patients was studied in vitro. The inhibition of TPO by MMI was not restored either by dialysis or by dilution, but the inhibition by PTU was restored by both treatments. PTU interacted directly with the product of TPO action (oxidized iodide) in the reaction mixture without significantly affecting TPO activity. MMI interacted directly with TPO and inhibited enzyme activity, rather than interacting with the product (oxidized iodide). The inhibition was irreversible with MMI, but reversible with PTU. The concentrations of PTU and MMI producing 50% inhibition of TPO were 2 x 10-6m and 8 x 10-7m, respectively, 2-Mercaptoimidazole inhibited TPO reversibly but 1-methylimidazole and imidazole did not. Both the methyl and mercaptoresidues in MMI moiety are thought to be essential to its irreversible inhibition of TPO. The in vivo effect of MMI and PTU on TPO activity was also studied. TPO activities in the thyroid homogenate of rats to which MMI (2 mg per rat) or PTU (10 mg per rat) had been administered intraperitoneally were determined before and after dialysis against buffer. TPO activity in the PTU treated thyroid homogenate was significantly lower than that in the control before dialysis, but the activity was restored to the control value after dialysis. On the contrary, TPO activity in the MMI treated thyroid homogenate was significantly lower than that in the control and was not affected by dialysis. These data may explain why MMI is a more potent inhibitor of iodination than PTU and may fit the clinical results observed when hyperthyroid patients are treated with these agents. PMID:947933

Nagasaka, A; Hidaka, H

1976-07-01

193

High-performance liquid chromatography of nucleic acid constituents: Chromatographic examination of novel stationary phases  

Microsoft Academic Search

SummarySilica-bonded stationary phases were developed for the separation of nucleic acid constituents and their properties investigated\\u000a with homologous oligoriboadenylic acids in electrostatic interaction chromatography and with alkylbenzenes in reversed-phase\\u000a chromatography. Analysis of retention data confirmed the stratified molecular structure of the surface which consist of a\\u000a layer of propyl chains anchoredvia siloxane bridges to the silica surface proper and of

Z. El Rassi; Cs. Horvth

1984-01-01

194

A novel Aspergillus oryzae esterase that hydrolyzes 4-hydroxybenzoic acid esters.  

PubMed

In this study we report the biochemical characterization of a hypothetical protein from Aspergillus oryzae exhibiting sequence identity with feruloyl esterase and tannase from the genus Aspergillus. The purified recombinant protein showed a hydrolytic activity toward the ethyl, propyl, or butyl esters of 4-hydroxybenzoic acid, but did not show feruloyl esterase or tannase activity. Finally, the enzyme decreased the antimicrobial activity of parabens against A. oryzae via hydrolysis of the ester bond present in butyl 4-hydroxybenzoic acid. PMID:20728445

Koseki, Takuya; Mihara, Koji; Murayama, Tetsuya; Shiono, Yoshihito

2010-08-20

195

The Use of Fatty Acid Esters to Enhance Free Acid Sophorolipid Synthesis  

Microsoft Academic Search

Fatty acid esters were prepared by transesterification of soy oil with methanol (methyl-soyate, Me-Soy), ethanol (ethyl-soyate,\\u000a Et-Soy) and propanol (propyl-soyate, Pro-Soy) and used with glycerol as fermentation substrates to enhance production of free-acid\\u000a sophorolipids (SLs). Fed-batch fermentations of Candida bombicola resulted in SL yields of 46 4g\\/l, 42 7g\\/l and 18 6g\\/l from Me-Soy, Et-Soy, and Pro-Soy, respectively. Liquid chromatography

Richard D. Ashby; Daniel K. Y. Solaiman; Thomas A. Foglia

2006-01-01

196

The Quest for Complex Molecules in Space. Searches for Cyanides Related to n-PROPYL Cyanide in SGR B2(N)  

NASA Astrophysics Data System (ADS)

A molecular line survey was carried out with the IRAM 30 m telescope toward the prolific hot core Sgr B2(N) in order to explore its molecular complexity. The entire 3 mm range as well as selected regions at 2 and 1.3 mm were covered. Notable results include the detections of aminoacetonitrile, ethyl formate, n-propyl cyanide,^b and the singly substituted 13C isotopologs of vinyl cyanide. There exists a branched isomer of n-propyl cyanide: iso-propyl cyanide. A search for this isomer in our line survey required a laboratory spectroscopic investigation beforehand. Even though promising emission features have been found for this as well as other, related molecules, there are rather few uncontaminated lines. Overlap by other emission or some absorption features occurs frequently, and uncertainties about the position of the baseline also contribute to considering detections to be inconclusive. Nevertheless, the determination of upper limits or abundances among isomers and related molecules will help to constrain astrochemical pathways. We will present our results and discuss promising strategies to search for complex molecules in space. A. Belloche, K. M. Menten, C. Comito, H. S. P. Mller, P. Schilke, J. Ott, S. Thorwirth, C. Hieret, Astron. Astrophys. 482 (2008) 179. A. Belloche, R. T. Garrod, H. S. P. Mller, K. M. Menten, C. Comito, P. Schilke, Astron. Astrophys. 499 (2009), 215. H. S. P. Mller, A. Belloche, K. M. Menten, C. Comito, P. Schilke, J. Mol. Spectrosc. 251 (2008) 319. H. S. P. Mller, A. Coutens, A. Walters, J.-U. Grabow, S. Schlemmer, submitted to J. Mol. Spectrosc.

Mller, Holger S. P.; Schlemmer, S.; Belloche, A.; Menten, K. M.; Coutens, A.; Walters, A.; Grabow, J.-U.

2011-06-01

197

Preliminary study of propyl bromide exposure among New Jersey dry cleaners as a result of a pending ban on perchloroethylene.  

PubMed

Many states are considering, and some states have actively pursued, banning the use of perchloroethylene (PERC) in dry cleaning establishments. Proposed legislation has led many dry cleaners to consider the use of products that contain greater than 90% n-propyl bromide (n-PB; also called 1-bromopropane or 1-BP). Very little information is known about toxicity and exposure to n-PB. Some n-PB-containing products are marketed as nonhazardous and "green" or "organic." This has resulted in some users perceiving the solvent as nontoxic and has resulted in at least one significant poisoning incident in New Jersey. In addition, many dry cleaning operators may not realize that the machine components and settings must be changed when converting from PERC to n-PB containing products. Not performing these modifications may result in overheating and significant leaks in the dry cleaning equipment. A preliminary investigation was conducted of the potential exposures to n-PB and isopropyl bromide (iso-PB; also called 2-bromopropane or 2-BP) among dry cleaners in New Jersey who have converted their machines from PERC to these new solvent products. Personal breathing zone and area samples were collected using the National Institute for Occupational Safety and Health Sampling and Analytical Method 1025, with a slight modification to gas chromatography conditions to facilitate better separation of n-PB from iso-PB. During the preliminary investigation, exposures to n-PB among some workers in two of three shops were measured that were greater than the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) for n-PB. The highest exposure measured among a dry cleaning machine operator was 54 parts per million (ppm) as an 8-hr time-weighted average, which is more than 5 times the ACGIH TLV of 10 ppm. The preliminary investigation also found that the work tasks most likely to result in the highest short-term exposures included the introduction of solvent to the machine, maintenance of the machine, unloading and handling of recently cleaned clothes, and interrupting the wash cycle of the machine. In addition, this assessment suggested that leaks may have contributed to exposure and may have resulted from normal machine wear over time, ineffective maintenance, and from the incompatibility of n-PB with gasket materials. PMID:20863050

Blando, James D; Schill, Donald P; De La Cruz, Mary Pauline; Zhang, Lin; Zhang, Junfeng

2010-09-01

198

Heat of Mixing and Solution of Propyl benzoate C10H12O2 + C11H24 Undecane (HMSD1111, LB4170_H)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Brnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Heat of Mixing and Solution of Propyl benzoate C10H12O2 + C11H24 Undecane (HMSD1111, LB4170_H)' providing data from direct low-pressure calorimetric measurement of molar excess enthalpy at variable mole fraction and constant temperature.

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

199

Synthesis and characterization of a new surface derivatizing reagent to promote the adhesion of polypyrrole films to n-type silicon photoanodes: N-(3-(trimethoxysilyl)propyl) pyrrole  

SciTech Connect

The synthesis, characterization, and application of N-(3-(trimethoxysilyl-propyl)pyrrole (I) as a photoanode derivatizing reagent that can be covalently anchored to the electrode via reaction of surface OH groups are described. The pendant group of I can then be used as the initiation site for polymerization of polypyrrole. The treatment of both Pt and n-type Si electrodes with I and films of polypyrrole to protect the semiconductor from photoanodic decomposition is described. Improved durability noted for the treated n-type Si electrodes is attributed to less H/sub 2/O/electrolyte undermining of the polymer when it is covalently anchored to the surface. (BLM)

Simon, R.A.; Ricco, A.J.; Wrighton, M.S.

1982-04-07

200

Antiarrhythmic and hypotensive activities of 1-[2-hydroxy-3-(4-phenyl-1-piperazinyl)propyl]-pyrrolidin-2-one (MG-1(R,S)) and its enantiomers.  

PubMed

The compound MG-1(R,S), (1-[2-hydroxy-3(4-phenyl-1-piperazinyl)propyl]-pyrrolidin-2-one, and its enantiomers were tested for electrocardiographic, antiarrhythmic and hypotensive activities. The racemic mixture (MG-1(R,S)) and its S-enantiomer significantly decreased systolic and diastolic blood pressure and possessed antiarrhythmic activity. The S-enantiomer displayed the greatest effect. The R-enantiomer did not show antiarrhythmic or hypotensive activity. The results suggest that the antiarrhythmic and hypotensive effects of these compounds are related to their adrenolytic properties. PMID:21602601

Sapa, Jacek; Filipek, Barbara; Nowi?ski, Leszek

2011-01-01

201

Methods of preparation of halonitroacetic acid derivatives and study of the fungicidal activity of their amides and anilides on Sclerotinia sclerotiorum  

Microsoft Academic Search

Anilides (II)-(XIII), (XV), (XVI), (XIX), and chloronitroacetamide (XVIII) were obtained in a yield of 3890% by ammonolysis of the corresponding dichloro- (I) and chloronitroacetyl chlorides (XIV). Dichloronitroacetanilides (II), (V), ethyl (XX), propyl (XXI) esters and amide of dichloronitroacetic acid (XXII) were obtained by chlorination of anhydrous ammonium and sodium salts by sulfuryl chloride in absolute ether. Bromination of anhydrous salts

A. I. Yurtanov; V. I. Anufriev; E. V. Kulish; N. G. Mikhailyuchenko; I. I. Shulyak

1991-01-01

202

Effects of polytherapy with phenytoin, carbamazepine, and stiripentol on formation of 4-ene-valproate, a hepatotoxic metabolite of valproic acid  

Microsoft Academic Search

The incidence of valproic acid hepatotoxicity has been reported to increase in patients who are receiving polytherapy. A minor valproic acid metabolite, 2-propyl-4-pentenoic acid (4-ene-VPA), formed by a cytochrome P450-mediated reaction, has been shown to be a potent inducer of microvesicular steatosis in rats. This study tested the hypothesis that formation of 4-ene-VPA would be increased in patients taking valproic

Ren H Levy; Albert W Rettenmeier; Gail D Anderson; Alan J Wilensky; Patrick N Friel; Thomas A Baillie; Andrew Acheampong; Jacques Tor; Martine Guyot; Pierre Loiseau

1990-01-01

203

The anisotropy of poly(acrylic acid) in composites with liquid crystalline cellulose derivatives as seen by low-frequency Raman spectroscopy  

Microsoft Academic Search

The low-frequency Raman scattering (LFRS) was used in order to determine the orientation of poly(acrylic acid) in anisotropy composite with liquid crystalline [(propionyloxy)propyl]cellulose (PPC). The photopolymerisation of acrylic acid in the presence of PPC leads to the formation of the poly(acrylic acid) (pAA) anisotropic network. This anisotropy is stable even at temperatures higher than the temperature of the optical isotropisation

Marcin Kozanecki; Eugene Duval; Jacek Ulanski; Lidia Okrasa; Lucien Saviot

2000-01-01

204

Silica chemically bonded N-propyl kriptofix 21 and 22 with immobilized palladium nanoparticles for solid phase extraction and preconcentration of some metal ions.  

PubMed

Silica gel chemically bonded N-propyl kriptofix 21 (SBNPK 21) and N-propyl kriptofix 22 (SBNPK 22) and subsequently immobilized with palladium nanoparticles (PNP-SBNPK 21 and PNP-SBNPK 22) to produce two new complexing lipophilic materials. Then these novel sorbents were applied for the enrichment of some metal ions and their subsequent determination by flame atomic absorption spectroscopy (FAAS). The influences of the variables including pH, amount of solid phase, sample flow rate, eluent conditions and sample volume on the metal ion recoveries were investigated. The detection limit of proposed method was in the interval 2.1-2.3 and 1.7-2.8 ng mL(-1) for PNP-SBNPK 21 and PNP-SBNPK 22 respectively, while the preconcentration factor was 80 for two sorbents. The relative standard deviations of recoveries were between 1.23-1.31 and 1.28-1.49 for PNP-SBNPK 21 and PNP-SBNPK 22 respectively. The method has high sorption-preconcentration efficiency even in the presence of various interfering ions. Due to the reasonable selectivity of proposed method, the relative standard deviation of recoveries of all understudied metal ions in some complicated matrices was less than 3.0%. PMID:23706199

Ghaedi, Mehrorang; Niknam, Khodabakhsh; Zamani, Saeed; Larki, Habib Abasi; Roosta, Mostafa; Soylak, Mustafa

2013-04-06

205

The carboxyl modifier 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide (EDC) inhibits half of the high-affinity Mn-binding site in photosystem II membrane fragments  

SciTech Connect

The diphenylcarbazide (DPC)/Mn{sup 2+} assay was used to assess the amount of the high-affinity Mn-binding site in manganese-depleted photosystem II (PS II) membrane fragments from spinach and Scenedesmus obliquus. The assay mechanism at high DPC concentration was shown to involve noncompetitive inhibition of only half of the control level of DPC donation to PS II by micromolar concentrations of Mn at pH 6.5. At low DPC concentration both DPC and Mn{sup 2+} donate to PS II additively. Treatment with the carboxyl amino acid modifier 1-ethyl-3-(3(dimethylamino) propyl) carbodiimide (EDC) inhibited half of the high affinity Mn-binding site in spinach and Scenedesmus WT PS II membranes and all of the available site in Scenedesmus LF-1 mutant PS II membranes. A similar EDC concentration dependence was observed in all cases. This protection was specific for Mn{sup 2+}; six other divalent cations were ineffective. The authors conclude that EDC modifies that half of the high-affinity Mn-binding site that is insensitive to the histidine modifier diethyl pyrocarbonate (DEPC) and directly affects ligands that bind Mn. The effects of EDC and DEPC that influence the high-affinity site are mutually exclusive and are specific to the lumenal side of the PS II membrane. They suggest that carboxyl residues on reaction center proteins are associated with half of the high-affinity Mn-binding site in PS II and are involved along with histidine residues in binding Mn functional in the O{sub 2}-evolving process.

Preston, C.; Seibert, M. (Solar Energy Research Inst., Golden, CO (United States))

1991-10-08

206

Non-covalent calixarene-amino acid complexes formed by MALDI-MS  

Microsoft Academic Search

Non-covalent inclusion complexes formed between amino acids and derivatized calix[6]arenes are observed in MALDI mass spectrometry.\\u000a The methyl, ethyl, and propyl ester derivatives of calix[6]arene yielded amino acid complexes, while the smaller calix[4]arene\\u000a analogs did not. Similarly the underivatized calix[6]arene and calix[4]arene did not produce complexes. Amino acid complexes\\u000a were observed for nearly all 20 amino acids in time-of-flight (TOF)

Michele M. Stone; Andreas H. Franz; Carlito B. Lebrilla

2002-01-01

207

Candidate reference method: Determination of valproic acid in serum by isotope-dilution mass spectrometry  

Microsoft Academic Search

SummaryA method has been developed for the determination of valproic acid, without derivatization, in human serum by isotope-dilution\\u000a mass spectrometry using labelled 2-propyl[3,3,3-d3] valeric[5,5,5-d3] acid as internal standard for accurate quantification of the concentration of valproic acid in the sample. After acidification,\\u000a the analyte and internal standard are extracted withn-hexane. The amounts of valproic acid in the serum are calculated

F. Susanto; H. Reinauer

1995-01-01

208

Candidate reference method: Determination of valproic acid in serum by isotope-dilution mass spectrometry  

Microsoft Academic Search

SummaryA method has been developed for the determination of valproic acid, without derivatization, in human serum by isotope-dilution\\u000a mass spectrometry using labelled 2-propyl[3,3,3-d3]valeric[5,5,5-d3] acid as internal standard for accurate quantification of the concentration of valproic acid in the sample. After acidification,\\u000a the analyte and internal standard are extracted withn-hexane. The amounts of valproic acid in the serum are calculated from

F. Susanto; H. Reinauer

1995-01-01

209

Increase in plasma free fatty acids and natriuresis by xanthines may reflect adenosine antagonism  

Microsoft Academic Search

The hypothesis has been examined that adenosine is involved in the diuretic and free fatty acid (FFA) releasing action of xanthines. The effects of theophylline (T), a potent adenosine antagonist, were compared with those of enprofylline (3-propyl xanthine, E), which exerts negligible antagonism of adenosine. Eight healthy male volunteers were given E 1.5 mg\\/kg, T 5.0mg\\/kg or placebo 0.9%

K.-E. Andersson; N. Johannesson; B. Karlberg; C. G. A. Persson

1984-01-01

210

Low chain esters of stearic acid as phase change materials for thermal energy storage in buildings  

Microsoft Academic Search

Esterification of different commercial mixtures of stearic and palmitic acid with methyl, butyl and propyl alcohols was undertaken at the laboratory scale and the thermal properties of the esters were determined by Differential Scanning Calorimetry (DSC).Twelve products were obtained with melting points in the interval of 1734C and freezing points in the range of 2032C. About half of them are

D. Feldman; D. Banu; D. Hawes

1995-01-01

211

Di-?-thio-cyanato-bis-{[1,2-bis-(diiso-propyl-phosphan-yl)-1,2-dicarba-closo-dodeca-borane]silver(I)}  

PubMed Central

The title compound, [Ag2(NCS)2(C14H38B10P2)2], was synthesized by the reaction of 1,2-bis(diisopropylphosphanyl)-1,2-dicarba-closo-dodecaborane with AgSCN. The diisopropylphosphanyl-closo-carborane ligand is coordinated in a bidentate manner to the AgI atom through the two P atoms. The coordination of the AgI atom is distorted tetrahedral, in which two vertices are formed by the P atoms of the chelating diphosphine ligand, and the other two are occupied by the S and N atoms of the two bridging thiocyanate anions, leading to a centrosymmetric binuclear complex. The distance between the two C atoms in the carborane skeleton is 1.851?(6)?.

Yang, Liguo; Zhu, Chengchen; Li, Dacheng

2011-01-01

212

ESR study of dialkyl carbonate radical anions and their thermal and photochemical dissociation in the solid state. [Dimethyl, diethyl, di-n-propyl carbonates  

SciTech Connect

Dialkyl carbonate radical anions have been identified by ESR spectroscopy in ..gamma..-irradiated samples of the parent compounds at 77/sup 0/K. The ..cap alpha..-/sup 13/C hyperfine couplings (A/sub double vertical bar/ = 159.5 G, A/sub perpendicular to/ = 127.8 G) for the dimethyl carbonate radical anion were measured with a /sup 13/C-enriched sample, and they show that the radical is pyramidal at the ..cap alpha.. carbon, as expected. Also, comparison with analogous radicals indicates appreciable spin delocalization onto the carbonyl oxygen. These dialkyl carbonate radical anions were found to undergo both a thermal and a photochemical ..beta..-scission reaction to produce the corresponding alkyl radicals. In addition to studies on polycrystalline dimethyl carbonate and diethyl carbonate, polycrystalline and glassy samples of di-n-propyl carbonate were examined, and similar results obtained for all four systems.

Hudson, R.L. (Eckerd Coll., St. Petersburg, FL); Williams, F.

1981-03-05

213

Pi-Complexed Beta-Arylalkyl Derivatives. IV. The Preparation and Solvolysis of 2-(pi-(Phenyl) chromium tricarbonyl) ethyl and 2-(pi (Phenyl) chromium tricarbonyl) -1-propyl Methanesulfonates and Their Noncomplexed Analogs.  

National Technical Information Service (NTIS)

The pi-(arene)chromium tricarbonyl complexed methanesulfonates 2-phenylethyl (2-OMs), 2-phenylethyl-1,1-d2 (4-OMs), and 2-phenyl-1-propyl (dl-6-OMs) have been prepared and their acetolysis and formolysis rates and/or products compared with those of the no...

K. K. Tse R. A. Mateer R. L. Veazey R. S. Bly

1972-01-01

214

Enhanced G4-DNA binding of 5,10,15,20 (N-propyl-4-pyridyl) porphyrin (TPrPyP4): a comparative study with TMPyP4.  

PubMed

The cationic porphyrin TPrPyP4, with four propyl substituents in the pyridinium rings, is evaluated in vitro by spectroscopic and polymerase-stop assays as a G4-DNA ligand and in cultured cells as a modulator of gene transcription. A comparison with the widely used TMPyP4 is presented. PMID:20820515

Cogoi, Susanna; Xodo, Luigi E

2010-09-06

215

ANALYSIS OF THE FLAME RETARDANT METABOLITES BIS (1,3-DICHLORO-2-PROPYL) PHOSPHATE (BDCPP) AND DIPHENYL PHOSPHATE (DPP) IN URINE USING LIQUID CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY  

PubMed Central

Organophosphate triesters tris-(1,3-dichloro-2-propyl) phosphate (TDCPP) and triphenyl phosphate (TPP) are widely used flame retardants (FRs) present in many products common to human environments, yet understanding of human exposure, and health effects of these compounds is limited. Monitoring urinary metabolites as biomarkers of exposure can be a valuable aid for improving this understanding; however, no previously published method exists for the analysis of the primary TDCPP metabolite, bis (1,3-dichloro-2-propyl) phosphate (BDCPP), in human urine. Here we present a method to extract the metabolites BDCPP and diphenyl phosphate (DPP) in human urine using mixed-mode anion exchange solid phase extraction and mass-labeled internal standards with analysis by atmospheric pressure chemical ionization liquid chromatography tandem mass spectrometry (APCI-LC/MS-MS). The method detection limit was 8 pg mL?1 urine for BDCPP and 204 pg mL?1 for DPP. Recoveries of analytes spiked into urine ranged from 82 10% to 91 4% for BDCPP and from 72 12% to 76 8% for DPP. Analysis of a small number of urine samples (n=9) randomly collected from non occupationally exposed adults revealed the presence of both BDCPP and DPP in all samples. Non-normalized urinary concentrations ranged from 461662 pg BDCPP mL?1 and 2877443 pg DPP mL?1, with geometric means of 147 pg BDCPP mL?1 and 1074 pg DPP mL?1. Levels of DPP were higher than those of BDCPP in 89% of samples. The presented method is simple and sufficiently sensitive to detect these FR metabolites in humans and may be applied to future studies to increase our understanding of exposure and potential health effects to FRs.

Cooper, EM; Covaci, A; van Nuijs, ALN; Webster, TF; Stapleton, HM

2013-01-01

216

Measurement of 15N\\/ 14N Isotopic Composition in Individual Plasma Free Amino Acids of Human Adults at Natural Abundance by Gas ChromatographyCombustion Isotope Ratio Mass Spectrometry  

Microsoft Academic Search

We describe a high-precision methodology to determine the15N\\/14N isotopic composition of 13 plasma free amino acids out of 500 ?l plasma, measured asN-pivaloyl-i-propyl amino acid esters by gas chromatographyisotope ratio mass spectrometry. It is now possible to measure15N isotopic natural abundances in plasma free amino acids, which has not been the case previously because of the minimum requirement of 60

Cornelia C. Metges; Klaus J. Petzke

1997-01-01

217

Urinary amino acid analysis: a comparison of iTRAQ-LC-MS/MS, GC-MS, and amino acid analyzer.  

PubMed

Urinary amino acid analysis is typically done by cation-exchange chromatography followed by post-column derivatization with ninhydrin and UV detection. This method lacks throughput and specificity. Two recently introduced stable isotope ratio mass spectrometric methods promise to overcome those shortcomings. Using two blinded sets of urine replicates and a certified amino acid standard, we compared the precision and accuracy of gas chromatography/mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) of propyl chloroformate and iTRAQ derivatized amino acids, respectively, to conventional amino acid analysis. The GC-MS method builds on the direct derivatization of amino acids in diluted urine with propyl chloroformate, GC separation and mass spectrometric quantification of derivatives using stable isotope labeled standards. The LC-MS/MS method requires prior urinary protein precipitation followed by labeling of urinary and standard amino acids with iTRAQ tags containing different cleavable reporter ions distinguishable by MS/MS fragmentation. Means and standard deviations of percent technical error (%TE) computed for 20 amino acids determined by amino acid analyzer, GC-MS, and iTRAQ-LC-MS/MS analyses of 33 duplicate and triplicate urine specimens were 7.27+/-5.22, 21.18+/-10.94, and 18.34+/-14.67, respectively. Corresponding values for 13 amino acids determined in a second batch of 144 urine specimens measured in duplicate or triplicate were 8.39+/-5.35, 6.23+/-3.84, and 35.37+/-29.42. Both GC-MS and iTRAQ-LC-MS/MS are suited for high-throughput amino acid analysis, with the former offering at present higher reproducibility and completely automated sample pretreatment, while the latter covers more amino acids and related amines. PMID:19481989

Kaspar, Hannelore; Dettmer, Katja; Chan, Queenie; Daniels, Scott; Nimkar, Subodh; Daviglus, Martha L; Stamler, Jeremiah; Elliott, Paul; Oefner, Peter J

2009-05-15

218

HPLC and TLC methodology for determination or purity evaluation of 4-methoxy-2-(3(4-phenyl-1-piperazinyl))propyl-2,3-dihydro-6-methyl-1,3-dioxo-1H-pyrrolo[3,4-c]pyridine.  

PubMed

A UV spectrophotometric analysis of 4-methoxy-2-(3 (4-phenyl-1-piperazinyl)) propyl-2,3-dihydro-6-methyl-1,3-dioxo-1H-pyrrolo [3,4-c] pyridine (II) in HCI (0.01 mole/L) was performed by determining the values of specific absorption coefficients at the following analytical wavelengths: 225, 285 and 350 nm. The separation by means of TLC of compound II and of its five decomposition products was also studied. Silica gel coated plates (60 F254) were used and the mobile phase consisted of butanol--acetic acid--water. A validated RP-HPLC method for the determination or purity evaluation of II, with phenacetin as an internal standard, is described. The solution of II in HCI (0.01 mole/L) was chromatographed on an octadecyl column (LiChrosorb 100 RP-18 column 250 x 4.0 mm I.D., dp = 5 microm) using an eluent composed of the mixture acetonitrile--phosphate buffer pH = 2. Ultraviolet detection was used at an operation wavelength of 239 nm. The HPLC method was validated by determination of the following parameters: selectivity, precision, accuracy, linearity, stability of the analite, LOD and LOQ. Kinetic studies of the decomposition process of II in both acidic and alkaline environments demonstrated the instability of the imide group. PMID:16022487

Muszalska, Izabela; Sladowska, Helena; Sabiniarz, Aleksandra

219

A new organofunctionalized silica containing thioglycolic acid incorporated for divalent cations removalA thermodyamic cation\\/basic center interaction  

Microsoft Academic Search

The silylating agent 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane was previously immobilized onto silica gel in heterogeneous route, followed by incorporation of thioglycolic acid. The elemental analysis for this final organofunctionalized silica has a degree of pendant chain of 0.27mmol per gram of the inorganic support. Infrared spectroscopy, thermogravimetry and 13CNMR data are in agreement with the covalent bond of organic moieties on silica, with

Andr L. P. Silva; Kaline S. Sousa; Ana F. S. Germano; Vaeudo V. Oliveira; Jos G. P. Espnola; Maria G. Fonseca; Claudio Airoldi; Tomaz Arakaki; Luiza N. H. Arakaki

2009-01-01

220

A simplified method for determining 1-aminocyclopropane-1-carboxylic acid (ACC) in plant tissues using a mass selective detector  

Microsoft Academic Search

A sensitive and specific method is described for the routine assay of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) in 100200 mg fresh weight samples of green or etiolated tissue. The method involves high performance liquid chromatography (HPLC) and gas chromatography linked to mass spectrometry (GCMS) and uses 14C-labelled ACC as an internal standard, N-benzoyl n-propyl ACC as an easily prepared

K. C. Hall; D. M. E. Pearce; M. B. Jackson

1989-01-01

221

Efficient synthesis of an imidazole-substituted delta-amino acid by the integration of chiral technologies.  

PubMed

Two methods to produce (2S)-5-amino-2-(1-n-propyl-1H-imidazol-4-ylmethyl)-pentanoic acid were investigated. Diastereoisomeric salt resolution, using the quinidine salt, gave the desired intermediate in 98% ee and 33% yield. Asymmetric hydrogenation of various substrates gave high conversions, with up to 83% ee. Integration of these two approaches via asymmetric hydrogenation of a quinidine salt substrate followed by crystallization provided the desired intermediate in 94% ee and 76% yield. PMID:15876022

Appleby, Ian; Boulton, Lee T; Cobley, Christopher J; Hill, Catherine; Hughes, Mike L; de Koning, Pieter D; Lennon, Ian C; Praquin, Cline; Ramsden, James A; Samuel, Helen J; Willis, Niamh

2005-05-12

222

Reduction of Benzenoid Synthesis in Petunia Flowers Reveals Multiple Pathways to Benzoic Acid and Enhancement in Auxin Transport  

Microsoft Academic Search

In plants, benzoic acid (BA) is believed to be synthesized from Phe through shortening of the propyl side chain by two carbons. It is hypothesized that this chain shortening occurs via either a b-oxidative or non-b-oxidative pathway. Previous in vivo isotope labeling and metabolic flux analysis of the benzenoid network in petunia (Petunia hybrida) flowers revealed that both pathways yield

Irina Orlova; Amy Marshall-Colon; Jennifer Schnepp; Barbara Wood; Marina Varbanova; Eyal Fridman; Joshua J. Blakeslee; W. A. Peer; A. S. Murphy; D. Rhodes; E. Pichersky; N. Dudareva

2006-01-01

223

Infrared frequency-modulation probing of product formation in alkyl + O2 reactions. Part IV. Reactions of propyl and butyl radicals with O2.  

PubMed

The time-resolved production of HO2 in the Cl-initiated oxidation of iso- and n-butane is measured using continuous-wave (CW) infrared frequency modulation spectroscopy between 298 and 693 K. The yield of HO2 is determined relative to the Cl2/CH3OH/O2 system. As in studies of smaller alkanes, the branching fraction to HO2 + alkene in butyl + O2 displays a dramatic rise with increasing temperature between about 550 and 700 K (the "transition region") which is accompanied by a qualitative change in the time behavior of the HO2 production. At low temperatures the HO2 is formed promptly; a second, slower production of HO2 is responsible for the bulk of the increased yield in the transition temperature region. In contrast to reactions of smaller alkyl radicals with O2, the total HO2 yield in the butyl radical reactions appears to remain significantly below 1 up to 700 K, implying a significant role for OH-producing channels. The slower HO2 production in butane oxidation displays an apparent activation energy similar to that measured for smaller alkyl + O2 reactions, suggesting that the energetics of the HO2 elimination transition state are similar for a broad range of R + O2 systems. A combination of QCISD(T) based characterizations of the propyl and butyl + O2 potential energy surfaces and master equation based characterization of the propyl + O2 kinetics provide the framework for explanation of the experimentally observed HO2 production in Cl-initiated propane and butane oxidation. These calculations suggest that the HO2 elimination channel is similar in all reaction systems, and that hydroperoxyalkyl (QOOH) species produced by internal H-atom abstraction in RO2 can provide a path to OH formation. However, the QOOH formed by the energetically favorable 1,5 isomerization (via a six-membered ring transition state) generally experiences significant barriers (relative to the radical + O2 reactants) to the production of an oxetane + OH. In contrast, the barriers to forming OH + an oxirane or an oxolane, via 1,4 or 1,6 isomerizations, respectively, are generally below reactants. PMID:11877987

DeSain, J D; Taatjes, C A; Miller, J A; Klippenstein, S J; Hahn, D K

2001-01-01

224

KNS-760704 [(6R)-4,5,6,7-tetrahydro-N6-propyl-2, 6-benzothiazole-diamine dihydrochloride monohydrate] for the treatment of amyotrophic lateral sclerosis.  

PubMed

Developing effective treatments for chronic neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS) has proven extremely difficult. ALS is universally fatal, characterized by progressive weakness due to the degeneration of upper and lower motor neurons, and leads eventually to respiratory failure which is the usual cause of death. Only a single treatment has been approved, the modestly effective nonspecific neuroprotectant Rilutek (riluzole; 2-amino-6-(trifluoromethoxy)benzothiazole). KNS-760704 [(6R)-4,5,6,7-tetrahydro-N6-propyl-2,6-benzothiazole-diamine dihydrochloride, RPPX], a synthetic amino-benzothiazole with demonstrated activity in maintaining mitochondrial function, is being developed as a treatment for ALS. It has proven to be effective in multiple in vitro and in vivo assays of neuroprotection, including the G93A-SOD1 mutant mouse model; however, its specific mechanism of action remains unknown. The potential of KNS-760604 as a treatment for ALS was first suggested by studies showing that its optical enantiomer, Mirapex[(6S)-4,5,6,7-tetrahydro-N6-propyl-2,6-benzothiazole-diamine; pramipexole dihydrochloride; PPX], a high-affinity agonist at dopamine D2, D3, and D4 receptors, exhibits important neuroprotective properties independent of its dopamine receptor agonism. In cell-based assays, both RPPX and PPX reduce the production of reactive oxygen species (ROS), attenuate the activation of apoptotic pathways, and increase cell survival in response to a variety of neurotoxins. However, PPX has limited utility as a clinical neuroprotective agent because the drug concentrations required for neuroprotection would likely produce unacceptable dopaminergic side effects. RPPX, on the other hand, while possessing the same neuroprotective potential as PPX, is a much lower-affinity dopamine receptor agonist and may therefore be more useful in the treatment of ALS. This review will examine the data supporting the hypothesis that the RPPX may have therapeutic potential for the treatment of neurodegenerative disorders including ALS. In addition, we will briefly review recent preclinical data in support of RPPX, and discuss the current status of its clinical development. PMID:18801114

Gribkoff, Valentin K; Bozik, Michael E

2008-01-01

225

Conducting Polymer Based Nucleic Acid Sensor for Environment Monitoring  

NASA Astrophysics Data System (ADS)

Nucleic acid sensor based on polyaniline has been fabricated by covalently immobilizing double stranded calf thymus (dsCT) DNA onto perchlorate (ClO-4) doped polyaniline (PANI) film deposited onto indium-tin-oxide (ITO) glass plate using 1-(3-(dimethylamino) propyl)-3-ethylcarbodiimide hydrochloride (EDC)/N-hydroxyl succinimide (NHS) chemistry. These dsCT-DNA-PANI/ITO and PANI/ITO electrodes have been characterized using square wave voltammetry, electrochemical impedance, and Fourier-transform-infra-red (FTIR) measurements. This disposable dsCT-DNA-PANI/ITO bioelectrode is stable for about four months, can be used to detect arsenic trioxide (0.1ppm) in 30s.

Malhotra, Bansi Dhar; Prabhakar, Nirmal; Solanki, Pratima R.

226

N-dibenzylphospho-N'-3-(2,6-dichlorophenyl)propyl-guanidine is a bisubstrate-analog for creatine kinase.  

PubMed

We describe a new compound, N-dibenzylphospho-N'-3-(2,6-dichlorophenyl)-propylguanidine (DPPG), and our study of its interaction with cytosolic CK. To our knowledge, it is the most potent inhibitor known for CK: the Ki value versus ADP was 330 nM and 110 nM for CK-MM and BB respectively. In view of the inhibition pattern, Ki(app) dependencies on the second substrate, and very low Ki values, we conclude that DPPG binds to the active site as a bisubstrate-type analog. This bisubstrate analog confirms different mechanisms for CK-MM and BB: in spite of a more than 80% similarity in amino-acid sequences, both isoenzymes are random at pH 8.6 but CK-BB has an ordered mechanism at pH 6.6. PMID:9366273

Min, K L; Steghens, J P; Henry, R; Doutheau, A; Collombel, C

1997-09-26

227

Diaqua-bis-(5-carb-oxy-2-propyl-1H-imidazole-4-carboxyl-ato-?2 N 3,O 4)cadmium N,N-dimethyl-formamide disolvate  

PubMed Central

In the title complex, [Cd(C8H9N2O4)2(H2O)2]2C3H7NO, the six-coordinate CdII ion is in a slightly distorted octahedral environment, defined by two O atoms from two coordinated water molecules and two carboxylate O atoms and two N atoms from two N,O-bidentate 5-carboxy-2-propyl-1H-imidazole-4-carboxylate ligands. In the crystal, complex molecules and dimethylformamide solvent molecules are linked by OH?O and NH?O hydrogen bonds into a two-dimensional supramolecular structure. The propyl groups of the ligands are disordered over two conformations with refined occupancies of 0.680?(7) and 0.320?(7).

Tong, Shao-Wei; Li, Shi-Jie; Song, Wen-Dong; Miao, Dong-Liang; An, Jing-Bo

2011-01-01

228

Synthesis and evaluation of N-alkyl-S-[3-(piperidin-1-yl)propyl]isothioureas: High affinity and human/rat species-selective histamine H3 receptor antagonists.  

PubMed

S-Alkyl-N-alkylisothiourea compounds containing various cyclic amines were synthesized in the search for novel nonimidazole histamine H3 receptor (H3R) antagonists. Among them, four N-alkyl S-[3-(piperidin-1-yl)propyl]isothioureas 18, 19, 22, and 23 were found to exhibit potent and selective H3R antagonistic activities against in vitro human H3R, but were inactive against in vitro human H4R. Furthermore, three alkyl homologs 18-20 showed inactivity for histamine release in in vivo rat brain microdialysis, suggesting differences in antagonist affinities between species. In addition, in silico docking studies of N-[4-(4-chlorophenyl)butyl]-S-[3-piperidin-1-yl)propyl]isothiourea 19 and a shorter homolog 17 with human/rat H3Rs revealed that structural differences between the antagonist-docking cavities of rat and human H3Rs were likely caused by the Ala122/Val122 mutation. PMID:24140447

Harusawa, Shinya; Sawada, Koichi; Magata, Takuji; Yoneyama, Hiroki; Araki, Lisa; Usami, Yoshihide; Hatano, Kouta; Yamamoto, Kouichi; Yamamoto, Daisuke; Yamatodani, Atsushi

2013-09-26

229

Antiulcer activity of the calcium antagonist propyl-methylenedioxyindene--I. Effect on cold/restraint stress-induced ulcers in rats.  

PubMed

1. Propyl-methylenedioxyindene (pr-MDI) is an intracellularly acting calcium antagonist with H2-receptor blocking properties. Stimulus-secretion coupling is inhibited by much lower concentrations of pr-MDI than is excitation-contraction coupling. 2. Since the processes leading to gastric ulceration are calcium-dependent, the aim of this study was to determine if pr-MDI could provide useful antiulcer activity at doses below those required to produce cardiovascular effects. 3. The antiulcer activity of pr-MDI (10-30 mg/kg) was examined in the cold (4 degree C)/restraint (3 hr) stress-induced ulcer model in male rats, and compared with the effects of the H2-blocker cimetidine (10-30 mg/kg) and the calcium channel blocker verapamil (11-32 mg/kg). The drugs were administered intraperitoneally 10 min prior to the cold/restraint stress. 4. All three drugs significantly reduced the number of ulcers and the cumulative length of ulcerated stomach surface in a roughly dose-dependent and equivalent manner. However, whereas the antiulcer doses of verapamil were extremely high, those of pr-MDI were one-sixth to one-half of its antiarrhythmic ED50 in rodents. PMID:2341019

Wong, W S; Rahwan, R G

1990-01-01

230

Quantitative determination of butylated hydroxyanisole and n-propyl gallate in cosmetics using three-dimensional fluorescence coupled with second-order calibration.  

PubMed

This work presents a novel approach for simultaneous determination of butylated hydroxyanisole (BHA) and propyl gallate (PG) in a very interfering environment by combining the sensitivity of molecular fluorescence and the selectivity of the second-order calibration method. The excitation-emission fluorescence matrix data are processed by applying the second-order calibration method based on the self-weighted alternating normalized residue fitting (SWANRF) algorithm. The limits of detection (LOD) were 1.2-1.3ng/ml for BHA and 2.2-2.9ng/ml for PG. The recoveries from spiked cosmetics samples are in the ranges 95.7-103.9% for BHA and 95.9-105.7% for PG. The proposed method avoids preconcentration and elution procedures, so it considerably decreases the analytical time and the experimental expenses. Because the instrument involved in the measurement is nonsophisticated, the experiments could be carried out in routine laboratories. Then it is compared with the HPLC method in dosage of cosmetics and organic reagents, runtime, cost per analysis and LOD. PMID:24148414

Wang, Jian-Yao; Wu, Hai-Long; Chen, Yao; Zhai, Min; Qing, Xiang-Dong; Yu, Ru-Qin

2013-06-05

231

Pharmacokinetics in melanoma-bearing mice of 5-dihydroxyboryl-6-propyl-2-thiouracil (BPTU), a candidate compound for boron neutron capture therapy.  

PubMed Central

Blood pharmacokinetics and tissue distribution of 5-dihydroxyboryl-6-propyl-2-thiouracil (BPTU), a boron carrier with postulated melanin-seeking properties for boron neutron capture therapy, were determined in C57/BL mice with subcutaneous pigmented or non-pigmented B16 melanomas. Borocaptate sodium (BSH) was used as a boron compound without melanin-seeking properties in a comparative biodistribution study in the same animal tumour models. Administration of single doses showed that BPTU was retained better in the pigmented B16 tumour than in the non-pigmented variant. BPTU was found in large concentrations in kidney and liver. Brain boron was approximately 10-fold lower than tumour boron. On a molar basis, BPTU demonstrated higher affinity for B16 tumours than BSH. Owing to solubility limits, tumour boron concentrations in this mouse study were too low for effective application of BNCT. However, the high tumour-to-blood and tumour-to-normal tissues ratios indicate that, with appropriate formulation, BPTU could be a promising candidate for clinical BNCT.

Verrijk, R.; Smolders, I. J.; Huiskamp, R.; Gavin, P. R.; Philipp, K. H.; Begg, A. C.

1994-01-01

232

Novel histamine H(3)-receptor antagonists with carbonyl-substituted 4-(3-(phenoxy)propyl)-1H-imidazole structures like ciproxifan and related compounds.  

PubMed

Novel histamine H(3)-receptor antagonists possessing a 4-(3-(phenoxy)propyl)-1H-imidazole structure generally substituted in the para-position of the phenyl ring have been synthesized according to Mitsunobu or S(N)Ar reactions. With in vitro and in vivo screening for H(3)-receptor antagonist potency, the carbonyl-substituted derivatives proved to be highly active compounds. A number of compounds showed in vitro affinities in the subnanomolar concentration range, and the 4-hexanoyl (10) and 4-acetyl-3-methyl (29) substituted derivatives showed in vivo antagonist potencies of about 0.1 mg/kg after po administration. Many proxifans were also tested for their affinities at other histamine receptor subtypes thereby demonstrating their pronounced H(3)-receptor subtype selectivity. Since the cyclopropyl ketone derivative 14 (ciproxifan) had high affinity in vitro as well as high potency in vivo, it was selected for further studies in monkeys. It showed good oral absorption and long-lasting, dose-dependent plasma levels making it a promising compound for drug development. PMID:11052804

Stark, H; Sadek, B; Krause, M; Hls, A; Ligneau, X; Ganellin, C R; Arrang, J M; Schwartz, J C; Schunack, W

2000-10-19

233

The control of cell adhesion and detachment on thin films of thermoresponsive poly[(N-isopropylacrylamide)-r-((3-(methacryloylamino)propyl)-dimethyl(3-sulfopropyl)ammonium hydroxide)].  

PubMed

This paper describes the formation of poly(N-isopropylacrylamide) (PNIPAAm) and poly[(N-isopropylacrylamide)-r-((3-(methacryloylamino)propyl)-dimethyl(3-sulfopropyl)ammonium hydroxide)] (P(NIPAAm-r-MPDSAH)) films on a glass surface via surface-initiated, atom transfer radical polymerization as a cell-culture platform. The films of PNIPAAm with various thicknesses and of P(NIPAAm-r-MPDSAH) with various ratios of NIPAAm and MPDSAH are formed to investigate the behaviors of cell adhesion and detachment. In the case of the PNIPAAm-grafted glass surfaces, the optimal film thickness, achieving the effective control of both cell adhesion and detachment, is estimated to be 11-13 nm for NIH 3T3 fibroblast cells. The adhesion and detachment behaviors of NIH 3T3 fibroblast cells are further tuned by incorporating the hydrophilic and non-biofouling MPDSAH moiety into the PNIPAAm system. The cell adhesion and detachment are controlled best, when the ratio of NIPAAm and MPDSAH is 75:1 (NIPAAm:MPDSAH). PMID:19646752

Kong, Bokyung; Choi, Joon S; Jeon, Saewha; Choi, Insung S

2009-07-30

234

Toxicogenomic Responses of Zebrafish Embryos/Larvae to Tris(1,3-dichloro-2-propyl) Phosphate (TDCPP) Reveal Possible Molecular Mechanisms of Developmental Toxicity.  

PubMed

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) is frequently present in indoor dust and can be detected in human milk. In order to evaluate the effects of TDCPP on vertebrate development, zebrafish embryos/larvae were used as an animal model to examine developmental phenotypes and explore possible mechanisms of toxicity by employing microarrays and iTRAQ labeling quantitative proteomics. The results demonstrated that treatment with TDCPP (3 ?M) from 0.75 h postfertilization (hpf) inhibited cell rearrangement at 4 hpf, caused delay in epiboly at 5.7 and 8.5 hpf, and led to abnormal development (e.g., short tail, reduced body size) and lethality between 14 and 45 hpf, which might be related with altered expression of genes regulating embryogenesis. Furthermore, trunk curvature was observed as the main phenotype in 96 hpf zebrafish larvae exposed to 1 or 3 ?M TDCPP, possibly by changing somite formation and expression of proteins related to fast muscle and cartilage development. Collectively, our results suggest that exposure to TDCPP causes developmental toxicity in vertebrates and warrant the need for studies to evaluate the potential health risks of TDCPP to developing human embryos/infants/children, due to its frequent presence in indoor dust and potential for human exposure. PMID:23919627

Fu, Jie; Han, Jian; Zhou, Bingsheng; Gong, Zhiyuan; Santos, Eduarda M; Huo, Xiaojing; Zheng, Weiling; Liu, Hongling; Yu, Hongxia; Liu, Chunsheng

2013-08-27

235

Pharmacological studies on a new thymoleptic antidepressant, 1-[3-(dimethylamino)propyl]-5-methyl-3-phenyl-1H-indazole (FS-32).  

PubMed

Some pharmacological actions of 1-[3-(dimethylamino)propyl]-5-methyl-3-phenyl-1H-indazole (FS-32), a newly synthesized indazole derivative, were investigated in comparison with imipramine. FS-32 showed anti-reserpine activity in a dose-dependent manner, whereas imipramine exhibited a bell-shaped dose-response pattern. Catecholaminergic potentiation was demonstrated with FS-32. The results obtained from a norepinephrine potentiation test in vitro suggest that FS-32 may act in a manner qualitatively different from the tricyclic antidepressant. FS-32 produced a definite suppressive effect on isolation-induced fighting without affecting coordinated motor activity and on the duration of afterdischarge elicited by electrical stimulation to the amygdala or the hippocampus without producing a slow wave pattern in the EEG. Similar effects on fighting behavior and the afterdischarge were shown under imipramine with a slight motor incoordination and with a slow wave pattern, respectively. FS-32 produced practically no peripheral anti-cholinergic action, while it antagonized central cholinergic activity. FS-32 tended to produce an increase in chatecholamine content in the brain without MAO or COMT inhibitory activity. Norepinephrine uptake was inhibited by FS-32, but less than by imipramine. These pharmacological properties suggest a potential clinical utility of FS-32 as an antidepressant possessing thymoleptic activities. PMID:114190

Ikeda, Y; Takano, N; Matsushita, H; Shiraki, Y; Koide, T; Nagashima, R; Fujimura, Y; Shindo, M; Suzuki, S; Iwasaki, T

1979-01-01

236

Mechanical and structural properties underlying contraction of skeletal muscle fibers after partial 1-ethyl-3-[3-dimethylamino)propyl]carbodiimide cross-linking.  

PubMed Central

We show prolonged contraction of permeabilized muscle fibers of the frog during which structural order, as judged from low-angle x-ray diffraction, was preserved by means of partial cross-linking of the fibers using the zero-length cross-linker 1-ethyl-3-[3-dimethylamino)propyl]carbodiimide. Ten to twenty percent of the myosin cross-bridges were cross-linked, allowing the remaining 80-90% to cycle and generate force. These fibers displayed a well-preserved sarcomeric order and mechanical characteristics similar to those of intact muscle fibers. The intensity of the brightest meridional reflection at 14.5 nm, resulting from the projection of cross-bridges evenly spaced along the myofilament length, decreased by 60% as a relaxed fiber was deprived of ATP and entered the rigor state. Upon activation of a rigorized fiber by the addition of ATP, the intensity of this reflection returned to 97% of the relaxed value, suggesting that the overall orientation of cross-bridges in the active muscle was more perpendicular to the filament axis than in rigor. Following a small-amplitude length step applied to the active fibers, the reflection intensity decreased for both releases and stretches. In rigor, however, a small stretch increased the amplitude of the reflection by 35%. These findings show the close link between cross-bridge orientation and tension changes. Images FIGURE 1 FIGURE 6

Bershitsky, S; Tsaturyan, A; Bershitskaya, O; Mashanov, G; Brown, P; Webb, M; Ferenczi, M A

1996-01-01

237

SolidPhase Microextraction Coupled with High Performance Liquid ChromatographyUV Detection for the Determination of Di-n-Propyl-phthalate, Di-iso-Butyl-phthalate, and Di-Cyclohexyl-phthalate in Environmental Water Samples  

Microsoft Academic Search

A simple method for the determination of di-n-propyl-phthalate, di-iso-butyl-phthalate, and di-cyclohexyl-phthalate in water samples using solid-phase microextraction coupled to high performance liquid chromatography and UV detection has been developed. Several kinds of commercially available coating fibers were evaluated for their extraction performance to the target analytes and the CW\\/TPR coating fibre was found to be the best one. The parameters

Yaqi Cai; Guibin Jiang; Jingfu Liu

2003-01-01

238

Synthesis and activity of novel 1- or 3-(3-amino-1-phenyl propyl)-1,3-dihydro-2H-benzimidazol-2-ones as selective norepinephrine reuptake inhibitors.  

PubMed

A series of novel 1- or 3-(3-amino-1-phenyl propyl)-1,3-dihydro-2H-benzimidazol-2-ones as selective norepinephrine reuptake inhibitors was discovered. Several compounds such as 15 and 20 showed good hNET potency. Compounds 15 and 20 also displayed excellent selectivity at hNET that appeared superior to those of reboxetine and atomoxetine (4 and 5). PMID:18951020

Zhang, Puwen; Terefenko, Eugene A; McComas, Casey C; Mahaney, Paige E; Vu, An; Trybulski, Eugene; Koury, Elizabeth; Johnston, Grace; Bray, Jenifer; Deecher, Darlene

2008-10-11

239

Two Stage Solid Phase Extraction with Subsequent HPLC Isolation for Structure Elucidation of Major Metabolites of (+)-(R)-2-{3-(benzo[1,4]dioxan-2-yl-methylamino)-1-propyl}-3(2H)-pyridazinone (GYKI-16084)  

Microsoft Academic Search

GYKI-16084 (+)-(R)-2-{3-(benzo[1,4]dioxan-2-yl-methylamino)-1-propyl}-3(2H)-pyridazinone hydrochloride is a new drug candidate for the treatment of benign prostatic hyperplasia. In our study the major metabolites formed in the rat and dog were isolated from dog and rat urine, then their structures were elucidated by means of MS and NMR. A two stage solid phase extraction (SPE) procedure and a semi-preparative HPLC method

K. Miglczi; Gy. Somorjai; M. Ptfalusi; G. Tth; Gy. Horvth; I. Hazai

2004-01-01

240

Measurements of activity coefficients at infinite dilution of organic solutes and water in 1-propyl-1-methylpiperidinium bis{(trifluoromethyl)sulfonyl}imide ionic liquid using g.l.c  

Microsoft Academic Search

Activity coefficients at infinite dilution (?13?) of 38 different solutes (including alkanes, cyclohydrocarbons, alkenes, alkynes, benzene, alkylbenzenes, alcohols, water, thiophene, THF, MTBE, ethers, acetone, and n-ketones) in the ionic liquid 1-propyl-1-methylpiperidinium bis{(trifluoromethyl)sulfonyl}imide have been determined by using the g.l.c. method and have been reported over the temperature range from (308.15 to 358.15)K. The partial molar excess enthalpies of mixing at

Urszula Doma?ska; Kamil Paduszy?ski

2010-01-01

241

Protective effects of l-pGlu-(2-propyl)- l-His- l-ProNH 2, a newer thyrotropin releasing hormone analog in in vitro and in vivo models of cerebral ischemia  

Microsoft Academic Search

In the present study, the newly synthesized TRH analog (l-pGlu-(2-propyl)-l-His-l-ProNH2; NP-647) was evaluated for its effects in in vitro (oxygen glucose deprivation (OGD)-, glutamate- and H2O2-induced injury in PC-12 cells) and in vivo (transient global ischemia) models of cerebral ischemic injury. PC-12 cells were subjected to oxygen and glucose deprivation for 6h. Exposure of NP-647 was given before and during

Satyendra Kumar Rajput; Maqsood Ahmad Siddiqui; Vivek Kumar; Chhuttan Lal Meena; Aditya Bhushan Pant; Rahul Jain; Shyam Sunder Sharma

2011-01-01

242

Silica bonded n-propyl-4-aza-1-azoniabicyclo[2.2.2]octane chloride (SB-DABCO): A highly efficient, reusable and new heterogeneous catalyst for the synthesis of 4 H-benzo[ b]pyran derivatives  

Microsoft Academic Search

The reaction of 3-chloropropyl silica with diazabicyclo[2.2.2]octane in dry acetone affords silica bonded n-propyl-4-aza-1-azoniabicyclo[2.2.2]octane chloride (SB-DABCO) as a new basic catalyst. The catalyst is used for the efficient synthesis of 4H-benzo[b]pyran derivatives via one-pot three-component reaction of cyclic ketones\\/1,3-diketones with aromatic aldehydes and alkylmalonates.

Alireza Hasaninejad; Mohsen Shekouhy; Nooshin Golzar; Abdolkarim Zare; Mohammad Mahdi Doroodmand

2011-01-01

243

A new approach to the preparation of lanthanide catalysts for the synthesis of 2-propyl-3-ethylquinoline based on the reactions of LnCl 3 6H 2 O crystalline hydrates with triisobutylaluminum  

Microsoft Academic Search

A new approach to the preparation of lanthanide catalysts for the synthesis of nitrogen heterocycles (exemplified by 2-propyl-3-ethylquinoline)\\u000a was developed based on the reactions of LnCl3 6H2O crystalline hydrates with alkylaluminums. It was found that the interaction of LnCl3 6H2O (Ln = Ce, Pr, Tb, and Eu) with iso-Bu3Al in aromatic solvents (20C) resulted in the formation of soluble (isobutane

R. G. Bulgakov; S. P. Kuleshov; A. R. Makhmutov; R. R. Vafin; D. S. Karamzina; M. T. Golikova; Ya. V. Shestopal; S. M. Usmanov; U. M. Dzhemilev

2006-01-01

244

1-[3-(2-[ 18 F]Fluoropyridin-3-yloxy)propyl]pyrrole-2,5-dione: Design, Synthesis, and Radiosynthesis of a New [ 18 F]Fluoropyridine-Based Maleimide Reagent for the Labeling of Peptides and Proteins  

Microsoft Academic Search

FPyME (1-(3-(2-fluoropyridin-3-yloxy)propyl)pyrrole-2,5-dione) was designed as a (18F)fluoropyridine- based maleimide reagent for the prosthetic labeling of peptides and proteins via selective conjugation with a thiol (sulfhydryl) function. Its pyridinyl moiety carries the radioactive halogen (fluorine-18) which can be efficiently incorporated via a nucleophilic heteroaromatic substitution, and its maleimido function ensures the efficient alkylation of a free thiol function as borne by

Batrice de Bruin; Bertrand Kuhnast; Franoise Hinnen; Loc Yaouancq; Mohamed Amessou; Ludger Johannes; Alain Samson; Raphal Boisgard; Bertrand Tavitian; Frederic Dolle

2005-01-01

245

Poly(2-hydroxyethyl methacrylate-co-sulfobetaine)s hydrogels: 3. Synthesis and swelling behaviors of the [2-hydroxyethyl methacrylate-co-N,N?-dimethyl (acrylamido propyl) ammonium propane sulfonate] hydrogels  

Microsoft Academic Search

A series of the 2-hydroxyethyl methacrylate\\/N,N?-dimethyl-(acrylamido propyl) ammonium propane sulfonate (HEMA\\/DMAAPS) copolymeric gels has been prepared from various molar ratios of HEMA and the zwitterionic monomer DMAAPS. The influence of the amount of zwitterionic monomer in the copolymeric gels on the swelling behaviors in water, various saline solutions, and various temperatures was investigated. Results indicated that in the equilibrium swelling

Wen-Fu Lee; Chin-Fu Chen

1998-01-01

246

Measurement of the Proportion of D2 Receptors Configured in State of High Affinity for Agonists in Vivo: A Positron Emission Tomography Study Using [11C]N-Propyl-norapomorphine and [11C]Raclopride in Baboons  

Microsoft Academic Search

Dopamine D2 receptors are configured in interconvertible states of high (D2 high) or low (D2 low) affinity for agonists. The in vivo proportion of sites in high-affinity state remains poorly documented. Previous studies have established the D2 agonist (11C)N-propyl-norapomorphine (NPA) as a suitable positron emission tomography radiotracer for imaging D2 high in the living brain. To elucidate the proportion of

Rajesh Narendran; Dah-Ren Hwang; Mark Slifstein; Yuying Hwang; Yiyun Huang; Jesper Ekelund; Olivier Guillin; Erica Scher; Diana Martinez; Marc Laruelle

2005-01-01

247

The dopamine stabilizers (S)-(-)-(3-methanesulfonyl-phenyl)-1-propyl-piperidine [(-)-OSU6162] and 4-(3-methanesulfonylphenyl)-1-propyl-piperidine (ACR16) show high in vivo D2 receptor occupancy, antipsychotic-like efficacy, and low potential for motor side effects in the rat.  

PubMed

"Dopamine stabilizers" are a new class of compounds that have the ability to reverse both hypo- as well as hyperdopaminergia in vivo. This class, exemplified by the phenylpiperidines (S)-(-)-3-(3-methanesulfonyl-phenyl)-1-propyl-piperidine [(-)-OSU6162] and 4-(3-methanesulfonyl-phenyl)-1-propyl)-piperidine [ACR16] although lacking high in vitro binding affinity for dopamine D2 receptor [(-)-OSU6162, Ki = 447 nM; ACR16, Ki > 1 microM], shows functional actions, suggestive of their interaction. Hence, we evaluated in vivo D2 occupancy of these agents in rats and correlated it to observed effects in a series of behavioral, neurochemical, and endocrine models relevant to the dopamine system and antipsychotic effect. Both (-)-OSU6162 and ACR16 showed robust dose-dependent striatal D2 occupancy with ED50 values of 5.27 and 18.99 mg/kg s.c., respectively, and functional assays showed no partial agonism. Over an occupancy range of 37 to 87% (3-60 mg/kg) for (-)-OSU6162 and 35 to 74% (10-60 mg/kg) for ACR16, we observed both inhibitory (amphetamine-induced locomotor activity) and stimulatory effects (in habituated rats). Haloperidol, over a similar occupancy range (33-78%), potently inhibited psychostimulant activity and induced catalepsy, but it failed to activate habituated animals. In the conditioned avoidance response assay, ACR16 was clearly more efficacious than (-)-OSU6162. In addition, both these compounds demonstrated significant preferential Fos induction in the nucleus accumbens compared with the dorsolateral striatum, a strong predictor of atypical antipsychotic efficacy. The results suggest that dopamine stabilizers exhibit locomotor stabilizing as well as antipsychotic-like effects, with low motor side effect liability, in a dose range that corresponds to high D2 in vivo occupancy. PMID:16648369

Natesan, Sridhar; Svensson, Kjell A; Reckless, Greg E; Nobrega, Jos N; Barlow, Karen B L; Johansson, Anette M; Kapur, Shitij

2006-04-28

248

Synthesis and study of the cytotoxic properties of bis-(2-fluoroethyl)-amino- and N,Nbis(2-chloroethyl)-hydrazine derivatives of furan  

Microsoft Academic Search

line, which they had synthesized. As for the manifestation of a definite antitumoral activity by preparations of the nitrofuran series, this was not unexpected, since it has been established that in contrast to most antibiotics, which usually influence processes of ceil replication, and sulfanilamides, which impair the assimilation of p-aminobenzoic acid, the mechanism of the action of nitrofurans consists of

R. Yu. Kalnberg; K. K. Venter; N. M. Sukhova; A. A. Zidermane; A. Zh. Dauvarte; M. Yu. Lidak; S. A. Giller

1968-01-01

249

Procaine-induced enhancement of fluid-phase endocytosis and inhibition of exocytosis in human skin fibroblasts  

Microsoft Academic Search

Local anaesthetics are often applied directly onto the skin, and for this reason the effect of some local anaesthetics upon morphology and cytoskeleton organisation in human skin fibroblasts was investigated. In this paper the authors report that procaine (p-aminobenzoic acid diethylamino-etyl ester hydrochloride) induced vacuolisation of cytoplasm and great enhancement of neutral red accumulation in human skin fibroblasts cultured in

Marta Michalik; Ma?gorzata Pierzchalska; Anna Pabia?czyk-Kulka; W?odzimierz Korohoda

2003-01-01

250

Effect of Mafenide on Dihydropteroate Synthase.  

National Technical Information Service (NTIS)

Using intact bacterial cells, it was found that Pseudomonas aeruginosa was more susceptible to mafenide than Escherichia coli, that p-aminobenzoic acid (pABA) did not reverse or prevent inhibition by mafenide and that pABA itself was inhibitory. Under the...

R. G. Eagon A. T. McManus

1990-01-01

251

Solid-Surface Luminescence Analysis: Progress Report, 1 December 1986-31 December 1987.  

National Technical Information Service (NTIS)

Modes of interaction of room-temperature solid-surface luminescence were studied for: p-aminobenzoic acid adsorbed on sodium acetate, 4-phenylphenol and bezo (f) quinoline adsorbed on filter paper, organic compounds adsorbed on 80% alpha -cyclodextrin-sod...

R. J. Hurtubise

1988-01-01

252

Solid-surface luminescence analysis: Progress report, 1 December 1986-31 December 1987  

SciTech Connect

Modes of interaction of room-temperature solid-surface luminescence were studied for: p-aminobenzoic acid adsorbed on sodium acetate, 4-phenylphenol and bezo (f) quinoline adsorbed on filter paper, organic compounds adsorbed on 80% ..cap alpha..-cyclodextrin-sodium choride mixtures, and extended luminescence calibration curves and solvent studies with nitrogen heterocycles. (DLC)

Hurtubise, R.J.

1988-01-01

253

Long-term stability of cell micropatterns on poly((3-(methacryloylamino)propyl)-dimethyl(3-sulfopropyl)ammonium hydroxide)-patterned silicon oxide surfaces.  

PubMed

In this work, we compared the long-term stability and integrity of cell patterns on newly reported, zwitterionic poly((3-(methacryloylamino)propyl)dimethyl(3-sulfopropyl)ammonium hydroxide) (poly(MPDSAH)) films with those on widely used, poly(poly(ethylene glycol) methyl ether methacrylate) (poly(PEGMEMA)) ones. The micropatterns of both polymers were formed on a silicon oxide surface by a combination of micropattern generation of a photoresist, vapor deposition of a silane-based polymerization initiator, and surface-initiated, atom transfer radical polymerization (SI-ATRP) of each monomer, MPDSAH or PEGMEMA. The successful formation of the silane initiator SAMs, and poly(MPDSAH) and poly(PEGMEMA) micropatterns was confirmed by X-ray photoelectron spectroscopy (XPS) and imaging ellipsometry. Onto each substrate patterned with poly(MPDSAH) or poly(PEGMEMA), NIH 3T3 fibroblast cells were seeded, and the cell micropatterns were generated by the selective adhesion of cells on the cell-adhesive region of the patterned surfaces. The cell pattern formed on the poly(MPDSAH)-patterned surface was observed to have a superior ability of finely maintaining its original, line-shaped structure up to for 20 days, when compared with the cell pattern formed on the poly(PEGMEMA)-patterned surface. In order to verify the relationship between the integrity of the cell micropatterns and the stability of the underlying non-biofouling polymer layers, we also investigated the long-term stability of the polymer films themselves, immersed in the cell culture media, for one month, in the aid of ellipsometry, contact goniometry, and XPS. PMID:21056465

Cho, Woo Kyung; Kong, Bokyung; Park, Hyung Ju; Kim, Jinkyu; Chegal, Won; Choi, Joon Sig; Choi, Insung S

2010-12-01

254

Nuclear factor ?B-dependent anti-inflammatory effects of s-allyl cysteine and s-propyl cysteine in kidney of diabetic mice.  

PubMed

Renal protection of s-allyl cysteine (SAC) and s-propyl cysteine (SPC) in diabetic mice against inflammatory injury was examined. Each agent at 0.5 and 1 g/L was added to the drinking water for 10 weeks. SAC or SPC intake significantly reduced the plasma blood urea nitrogen level and increased creatinine clearance (P < 0.05). These treatments significantly lowered the renal level of reactive oxygen species, nitric oxide, interleukin-6, tumor necrosis factor-?, and prostaglandin E(2) in diabetic mice (P < 0.05). Renal mRNA expression of inducible nitric oxide synthase, cyclooxygenase-2, protein kinase C (PKC)-?, PKC-?, and PKC-? was enhanced in diabetic mice (P < 0.05); however, SAC or SPC treatments dose dependently declined mRNA expression of these factors (P < 0.05). Nuclear factor ?B (NF-?B) activity, mRNA expression, and protein production in kidney of diabetic mice were significantly increased (P < 0.05). SAC or SPC intake dose dependently suppressed NF-?B activity, NF-?B p65 mRNA expression, and protein level (P < 0.05). Diabetes also enhanced renal protein expression of mitogen-activated protein kinase (P < 0.05). SAC and SPC, only at a high dose, significantly suppressed protein production of p-p38 and p-ERK1/2 (P < 0.05). Renal mRNA expression and protein generation of peroxisome proliferator-activated receptor (PPAR)-? and PPAR-? were significantly down-regulated in diabetic mice (P < 0.05), but the intake of SAC or SPC at high dose up-regulated PPAR-? and PPAR-? (P < 0.05). These findings support that SAC and SPC are potent anti-inflammatory agents against diabetic kidney diseases. PMID:22394022

Mong, Mei-chin; Yin, Mei-chin

2012-03-16

255

s-Allyl cysteine, s-ethyl cysteine, and s-propyl cysteine alleviate ?-amyloid, glycative, and oxidative injury in brain of mice treated by D-galactose.  

PubMed

The neuroprotective effects of s-allyl cysteine, s-ethyl cysteine, and s-propyl cysteine in D-galactose (DG)-treated mice were examined. DG treatment increased the formation of A?(1-40) and A?(1-42), enhanced mRNA expression of ?-amyloid precursor protein (APP) and ?-site APP cleavage enzyme 1 (BACE1), and reduced neprilysin expression in brain (P < 0.05); however, the intake of three test compounds significantly decreased the production of A?(1-40) and A?(1-42) and suppressed the expression of APP and BACE1 (P < 0.05). DG treatments declined brain protein kinase C (PKC) activity and mRNA expression (P < 0.05). Intake of test compounds significantly retained PKC activity, and the expression of PKC-? and PKC-? (P < 0.05). DG treatments elevated brain activity and mRNA expression of aldose reductase (AR) and sorbitol dehydrogenase as well as increased brain levels of carboxymethyllysine (CML), pentosidine, sorbitol, and fructose (P < 0.05). Test compounds significantly lowered AR activity, AR expression, and CML and pentosidine levels (P < 0.05). DG treatments also significantly increased the formation of reactive oxygen species (ROS) and protein carbonyl and decreased the activity of glutathione peroxidase (GPX), superoxide dismutase (SOD), and catalase (P < 0.05); however, the intake of test compounds in DG-treated mice significantly decreased ROS and protein carbonyl levels and restored brain GPX, SOD, and catalase activities (P < 0.05). These findings support that these compounds via their anti-A?, antiglycative, and antioxidative effects were potent agents against the progression of neurodegenerative disorders such as Alzheimer's disease. PMID:21548553

Tsai, Shih-Jei; Chiu, C Perry; Yang, Hui-Ting; Yin, Mei-Chin

2011-05-12

256

The dar genes of Pseudomonas chlororaphis PCL1606 are crucial for biocontrol activity via production of the antifungal compound 2-hexyl, 5-propyl resorcinol.  

PubMed

To determine the genetic basis by which 2-hexyl, 5-propyl resorcinol (HPR) is produced by the biocontrol rhizobacterium Pseudomonas chlororaphis (formerly known as P. fluorescens) PCL1606, the presence and role of dar genes were investigated. To accomplish this aim, the pCGNOV-1 plasmid was isolated from a PCL1606 genomic library and was shown to hybridize to various dar probes by Southern blot. An analysis of the pCGNOV-1 genomic DNA revealed the presence of five open reading frames that were homologous to dar genes and had an organization that resembled the arrangement of previously described P. chlororaphis strains. Phylogenetic studies resulted in the clustering of PCL1606 with the P. chlororaphis subgroup, which supported the renaming of this strain from P. fluorescens to P. chlororaphis PCL1606. The construction of insertional mutants for each homologous dar gene in P. chlororaphis PCL1606 along with their corresponding complemented derivative strains restored HPR production and confirmed the key role of the dar A and darB genes in HPR production and in the antagonistic phenotype. Finally, biocontrol assays were performed on avocado-Rosellinia and tomato-Fusarium test systems using the HPR-defective and -complemented derivative strains generated here and demonstrated the crucial role of the biosynthetic dar genes in the biocontrol phenotype of P. chlororaphis PCL1606. This biocontrol phenotype is dependent on the dar genes via their production of the HPR antibiotic. Some of the dar genes not directly involved in the biosynthesis of HPR, such as darS or darR, might contribute to regulatory features of HPR production. PMID:23547906

Caldern, Claudia E; Prez-Garca, Alejandro; de Vicente, Antonio; Cazorla, Francisco M

2013-05-01

257

Complete detoxification of tris(1,3-dichloro-2-propyl) phosphate by mixed two bacteria, Sphingobium sp. strain TCM1 and Arthrobacter sp. strain PY1.  

PubMed

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP), a flame retardant, is regarded as a potentially toxic and persistent environmental contaminant. We previously isolated a TDCPP-degrading bacterium, Sphingobium sp. strain TCM1, which, however, produced a toxic metabolite: 1,3-dichloro-2-propanol (1,3-DCP). This study was undertaken to develop a technique for complete TDCPP detoxification using strain TCM1 with a 1,3-DCP-degrading bacterium, Arthrobacter sp. strain PY1. For efficient detoxification, we designed a resting cell system and examined the effect of freezing and lyophilization treatments for preparation of their resting cells. Results show that treatments had no marked adverse effect on their activities. The TDCPP dephosphorylation by TCM1 resting cells was optimal at 30C and pH 8.5. Also, 1,3-DCP dehalogenation by strain PY1 resting cells was optimal at 35C and pH 9.5. Under those respective conditions, the activities were 2.48 ?mol h?OD???? for TDCPP and 0.95 ?mol h?OD???? for 1,3-DCP. Based on these results, we set the reaction temperature to 30C and pH to 9.0. Then we examined the detoxification of 50 ?M TDCPP using mixed resting cells at a final OD(660) of 0.05 for strain TCM1 and 0.2 for strain PY1. In these conditions, TDCPP was eliminated after 1h, but some of the resulting 1,3-DCP remained at a constant level. The increase in strain PY1 cells to a final OD??? of 4.0 decreased the TDCPP dephosphorylation rate of strain TCM1 cells but achieved complete detoxification of TDCPP during 12 h of reaction. PMID:21956155

Takahashi, Shouji; Obana, Yuki; Okada, Shohei; Abe, Katsumasa; Kera, Yoshio

2011-09-28

258

Enantioselective allylation of imines catalyzed by newly developed (-)-?-pinene-based ?-allylpalladium catalyst: an efficient synthesis of (R)-?-propylpiperonylamine and (R)-pipecolic acid.  

PubMed

A newly developed ?-allylpalladium with a (-)-?-pinene framework and an isobutyl side chain catalyzed the enantioselective allylation of imines in good yields and enantioselectivities (20 examples, up to 98% ee). An efficient enantioselective synthesis of the (R)-?-propyl piperonylamine part of DMP 777, a human leukocyte elastase inhibitor and (R)-pipecolic acid have been achieved as a useful application of this methodology. PMID:22910971

Fernandes, Rodney A; Nallasivam, Jothi L

2012-10-14

259

The effects of nitric acid and silane surface treatments on carbon fibers and carbon\\/vinyl ester composites before and after seawater exposure  

Microsoft Academic Search

This research focuses on carbon fiber treatment by nitric acid and 3-(trimethoxysilyl)propyl methacrylate silane, and how this affects carbon\\/vinyl ester composites. These composites offer great benefits, but it is difficult to bond the fiber and matrix together, and without a strong interfacial bond, composites fall short of their potential. Silanes work well with glass fiber, but do not bond directly

Tye A. Langston

2008-01-01

260

Effect of valproic acid on glycine conjugation of benzoic acid.  

PubMed

Conjugation with glycine proceeds through ATP-dependent coupling of carboxylic acids with coenzyme A (CoA). Therefore, chemicals that form CoA esters may interfere with glycine conjugation. We tested the hypothesis that valproic acid (VPA), which is esterified with CoA in the first step of its mitochondrial beta-oxidation, may compromise glycine conjugation of aromatic carboxylic acids, by investigating the effect of acute VPA administration on glycine conjugation of benzoic acid in rats. VPA administered 1 hr before injection of benzoate only decreased the blood clearance of benzoate and the urinary excretion of benzoylglycine slightly in normal rats. However, in rats loaded with glycine, 2 and 3 mmol/kg of VPA reduced the blood clearance of benzoate by 34 and 59%, diminished the peak blood level of the glycine conjugate and depressed the maximal urinary excretion rate of benzoylglycine by 28 and 66%, respectively. To elucidate the mechanism of VPA-induced inhibition of benzoylglycine formation, the effects of VPA on hepatic levels of cosubstrates and the activities of enzymes involved in glycine conjugation were also determined. One hour after administration of VPA, hepatic ATP levels remained unchanged, whereas the concentration of CoA was reduced by 67 to 73% and that of glycine was increased by 58 to 67%. Activities of the enzymes of glycine conjugation were not influenced by VPA. However, 2-n-propyl-4-pentenoic acid, a metabolite of VPA, inhibited benzoyl-CoA synthetase. In summary, VPA minimally influenced the capacity of glycine conjugation of benzoic acid in normal rats, but decreased it markedly in glycine-loaded rats.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8263766

Gregus, Z; Fekete, T; Varga, F; Klaassen, C D

1993-12-01

261

Urinary Amino Acid Analysis: A Comparison of iTRAQ(R)-LC-MS/MS, GC-MS, and Amino Acid Analyzer  

PubMed Central

Urinary amino acid analysis is typically done by cation-exchange chromatography followed by post-column derivatization with ninhydrin and UV detection. This method lacks throughput and specificity. Two recently introduced stable isotope ratio mass spectrometric methods promise to overcome those shortcomings. Using two blinded sets of urine replicates and a certified amino acid standard, we compared the precision and accuracy of gas chromatography/mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) of propyl chloroformate and iTRAQ derivatized amino acids, respectively, to conventional amino acid analysis. The GC-MS method builds on the direct derivatization of amino acids in diluted urine with propyl chloroformate, GC separation and mass spectrometric quantification of derivatives using stable isotope labeled standards. The LC-MS/MS method requires prior urinary protein precipitation followed by labeling of urinary and standard amino acids with iTRAQ tags containing different cleavable reporter ions distinguishable by MS/MS fragmentation. Means and standard deviations of percent technical error (%TE) computed for 20 amino acids determined by amino acid analyzer, GC-MS, and iTRAQ-LC-MS/MS analyses of 33 duplicate and triplicate urine specimens were 7.275.22, 21.1810.94, and 18.3414.67, respectively. Corresponding values for 13 amino acids determined in a second batch of 144 urine specimens measured in duplicate or triplicate were 8.395.35, 6.233.84, and 35.3729.42. Both GC-MS and iTRAQ-LC-MS/MS are suited for high-throughput amino acid analysis, with the former offering at present higher reproducibility and completely automated sample pretreatment, while the latter covers more amino acids and related amines.

Kaspar, Hannelore; Dettmer, Katja; Chan, Queenie; Daniels, Scott; Nimkar, Subodh; Daviglus, Martha L.; Stamler, Jeremiah; Elliott, Paul; Oefner, Peter J.

2009-01-01

262

A Chemogenomic Screening of Sulfanilamide-Hypersensitive Saccharomyces cerevisiae Mutants Uncovers ABZ2, the Gene Encoding a Fungal Aminodeoxychorismate Lyase?  

PubMed Central

Large-scale phenotypic analyses have proved to be useful strategies in providing functional clues about the uncharacterized yeast genes. We used here a chemogenomic profiling of yeast deletion collections to identify the core of cellular processes challenged by treatment with the p-aminobenzoate/folate antimetabolite sulfanilamide. In addition to sulfanilamide-hypersensitive mutants whose deleted genes can be categorized into a number of groups, including one-carbon related metabolism, vacuole biogenesis and vesicular transport, DNA metabolic and cell cycle processes, and lipid and amino acid metabolism, two uncharacterized open reading frames (YHI9 and YMR289w) were also identified. A detailed characterization of YMR289w revealed that this gene was required for growth in media lacking p-aminobenzoic or folic acid and encoded a 4-amino-4-deoxychorismate lyase, which is the last of the three enzymatic activities required for p-aminobenzoic acid biosynthesis. In light of these results, YMR289w was designated ABZ2, in accordance with the accepted nomenclature. ABZ2 was able to rescue the p-aminobenzoate auxotrophy of an Escherichia coli pabC mutant, thus demonstrating that ABZ2 and pabC are functional homologues. Phylogenetic analyses revealed that Abz2p is the founder member of a new group of fungal 4-amino-4-deoxychorismate lyases that have no significant homology to its bacterial or plant counterparts. Abz2p appeared to form homodimers and dimerization was indispensable for its catalytic activity.

Botet, Javier; Mateos, Laura; Revuelta, Jose L.; Santos, Maria A.

2007-01-01

263

The use of fatty acid esters to enhance free acid sophorolipid synthesis.  

PubMed

Fatty acid esters were prepared by transesterification of soy oil with methanol (methyl-soyate, Me-Soy), ethanol (ethyl-soyate, Et-Soy) and propanol (propyl-soyate, Pro-Soy) and used with glycerol as fermentation substrates to enhance production of free-acid sophorolipids (SLs). Fed-batch fermentations of Candida bombicola resulted in SL yields of 46 +/- 4 g/l, 42 +/- 7 g/l and 18 +/- 6 g/l from Me-Soy, Et-Soy, and Pro-Soy, respectively. Liquid chromatography with atmospheric pressure ionization mass spectrometry (LC/API-MS) showed that Me-Soy resulted in 71% open-chain SLs with 59% of those molecules remaining esterified at the carboxyl end of the fatty acids. Et-Soy and Pro-Soy resulted in 43% and 80% open-chain free-acid SLs, respectively (containing linoleic acid and oleic acid as the principal fatty acid species linked to the sophorose sugar at the omega-1 position), with no evidence of residual esterification. PMID:16555009

Ashby, Richard D; Solaiman, Daniel K Y; Foglia, Thomas A

2006-02-01

264

Metal extraction by silyl-substituted diphosphonic acids. II. Effect of alkylene bridge length on aggregation and metal ion extraction behavior  

Microsoft Academic Search

In an ongoing effort to determine the relationship between structure and function in diphosphonic acids, the aggregation and solvent extraction chemistry of four novel silicon-substituted diphosphonic acids, P,P?-di[3-(trimethylsilyl)-1-propyl] propylene- (H2DTMSP[PrDP]), butylene- (H2DTMSP[BuDP]), pentylene- (H2DTMSP[PDP]), and hexylene diphosphonic acid (H2DTMSP[HDP]), were investigated. Vapor pressure osmometry indicates that H2DTMSP[PrDP] and H2DTMSP[PDP] are dimeric in toluene at 25C, while H2DTMSP[BuDP] and H2DTMSP[HDP] are

D. R. McAlister; M. L. Dietz; R. Chiarizia; P. R. Zalupski; A. W. Herlinger

2002-01-01

265

Metal extraction by silyl-substituted diphosphonic acids. Part 2. Effect of alkyl bridge length on aggregation and metal ion extraction behavior  

Microsoft Academic Search

In an ongoing effort to determine the relationship between structure and function in diphosphonic acids, the aggregation and solvent extraction chemistry of four novel silicon-substituted diphosphonic acids, P,P'-di[3-(trimethylsilyl)-1-propyl] propylene- (HDTMSP[PrDP]), butylene- (HDTMSP[BuDP]), pentylene- (HDTMSP[PDP]), and hexylene diphosphonic acid (H2DTMSP[HDP]), were investigated. Vapor pressure osmometry indicates that HDTMSP[PrDP] and HDTMSP[PDP] are dimeric in toluene at 25 C, while HDTMSP[BuDP] and HDTMSP[HDP

D. R. McAlister; M. L. Dietz; R. Chiarizia; P. R. Zalupski; A. W. Herlinger

2002-01-01

266

Induction of S-phase arrest and p21 overexpression by a small molecule 2[[3-(2,3-dichlorophenoxy)propyl] amino]ethanol in correlation with activation of ERK  

Microsoft Academic Search

We recently found that a small molecule 2[[3-(2,3-dichlorophenoxy)propyl]amino]ethanol (2,3-DCPE) could induce apoptosis and downregulate Bcl-XL expression in various cancer cells. Here, we found that 2,3-DCPE suppressed the proliferation of Bcl-XL-overexpressing cancer cells without inducing apoptosis. Subsequently, we found that 2,3-DCPE could induce S-phase arrest and upregulate p21 but not p27 at a time- and dose-dependent but p53-dispensable manner in DLD-1

Hongbo Zhu; Lidong Zhang; Shuhong Wu; Fuminori Teraishi; John J Davis; Dietmar Jacob; Bingliang Fang; B Fang

2004-01-01

267

Multielement trace analysis by reversed-phase high-performance liquid chromatography followed by on-line column enrichment as 2-(5-nitro-2-pyridylazo)-5-[N-propyl-N-(3-sulphopropyl)amino] phenol chelates  

Microsoft Academic Search

This paper reports the utilization of 2-(5-nitro-2-pyridylazo)-5-[N-propyl-N-sulphopropyl)amino phenol (Nitro-PAPS) as a chelating reagent using an ODS column for the preconcentration and the separation of metal ions by reversed-phase high-performance liquid chromatography (RP-HPLC) with ultraviolet-visible detection of 570 nm. Nitro-PAPS chelates were eluted within 12 min with tetrahydrofuran-acetonitrile-water (15:10:75, v\\/v) containing a 0.01 mol dm?3 phosphate buffer solution (pH 6.0) and

Okutani Tadao; Tsukada Yuuichi; Sakuragawa Akio; Yamaji Takehiro; Morita Shiho

1997-01-01

268

The SAR of 6-(N-alkyl-N-acyl)-2-propyl-3-[(2?-tetrazol-5-yl)biphen-4-yl)methyl]-quinazolinones as balanced affinity antagonists of the human AT 1 and AT 2 receptors  

Microsoft Academic Search

Modification of the 6-N-alkyl-N-acyl groups of L-159,689, 6 6-(N-benzoyl-N-pentyl)-amino-2-propyl-3-[(2?-(tetrazol-5-yl)biphen-4-yl)methyl]quinazolin-4-(3H)one led to the identification of the 6-(N-benzoyl-N-(3-pyridylmethyl)) analog (L-162,537). L-162,537 had improved aqueous solubility and oral bioavailability in the dog. The SAR of this class of AT1 and AT2 ligands is discussed.

Stephen E. de Laszlo; Raymond S. Chang; Tsing-Bau Chen; Kristie A. Faust; William J. Greenlee; Salah D. Kivlighn; Victor J. Lotti; Stacey S. O'Malley; Terry W. Schorn; Peter K. Siegl; Jennifer Tran; Gloria J. Zingaro

1995-01-01

269

Synthesis and antimicrobial activity of 1-benzhydryl-sulfonyl-4-(3-(piperidin-4-yl) propyl)piperidine derivatives against pathogens of Lycopersicon esculentum: a structure-activity evaluation study.  

PubMed

Several 1-benzhydryl-sulfonyl-4-(3-(piperidin-4-yl)propyl)piperidine derivatives 8(a-j) were prepared by the treatment of substituted benzhydryl chlorides with 4-(3-(piperidin-4-yl)propyl)piperidine followed by N-sulfonation with sulfonyl chlorides in the presence of dry methylene dichloride and triethyl amine. The synthesized compounds were characterized by (1)H-NMR, IR, and elemental analysis. All the synthesized compounds were evaluated in vitro for their efficacy as antimicrobial agents by artificial inoculation technique against standard strains of two important bacterial viz., Xanthomonas axonopodis pv. vesicatoria and Ralstonia solanacearum as well as and two fungal pathogens namely Alternaria solani and Fusarium solani of tomato plants. We have briefly investigated the structure-activity relation studies and reveal that the nature of substitutions on benzhydryl ring and sulfonamide ring influences the antibacterial activity. Among the synthesized new compounds 8b, 8d, 8g, 8h, 8i, and 8j were showed significant potent antimicrobial activities compared to the standard drugs chloramphenicol, mancozeb. PMID:19183874

Vinaya, K; Kavitha, R; Ananda Kumar, C S; Benaka Prasad, S B; Chandrappa, S; Deepak, S A; Nanjunda Swamy, S; Umesha, S; Rangappa, K S

2009-01-29

270

Ophthalmic compositions with an amphoteric surfactant and hyaluronic acid  

US Patent & Trademark Office Database

Ophthalmic compositions that comprise 0.1 ppm to 10 ppm of a cationic antimicrobial component selected from the group consisting of biguanides, polymeric biguanides, quaternium ammonium compounds and any one mixture thereof; 0.005 wt. % to 0.15 wt. % of hyaluronic acid; and 0.01 wt. % to 1.0 wt. % of an amphoteric surfactant of general formula I ##STR00001## wherein R.sup.1 is R or --(CH.sub.2).sub.n--NHC(O)R, wherein R is a C.sub.8-C.sub.16alkyl optionally substituted with hydroxyl and n is 2, 3 or 4; R.sup.2 and R.sup.3 are each independently selected from methyl, ethyl, propyl or iso-propyl; and R.sup.4 is a C.sub.2-C.sub.8alkylene optionally substituted with hydroxyl. The invention is also direct to the use of the ophthalmic compositions to clean and disinfect contact lenses, and in particular, soft, silicone hydrogel contact lenses.

Xia; Erning (Penfield, NY); Burke; Susan E. (Batavia, NY); Venkatesh; Srini (Pittsford, NY); Barniak; Vicki (Fairport, NY)

2012-02-21

271

Weakly Antiferromagentic Coupling Via Superexchange Interaction Between Mn(II)-Mn(II) Atoms: A QM/MM Study of the Active Site of Human Cytosolic X-Propyl Aminopeptidase P  

PubMed Central

We investigate the dinuclear manganese, Mn(II)-Mn(II), active site of human cytosolic X-propyl aminopeptidase (XPNPEP1) employing the QM/MM method. The optimized structure supports two manganese atoms at the active site and excludes the possibility of a single Mn(II) atom or other combination of divalent metal ions: Ca(II), Fe(II), Mg(II). A broken symmetry solution verifies an antiferromagnetically coupled state between the Mn(II)-Mn(II) pair, which is the ground state. From the energy difference between the high spin state (HS) and the broken symmetry state (BS), we estimate the exchange coupling constant, J, to be 5.15 cm-1. Also, we observe multiple bridges (p orbitals) from solvent and two carboxylate linking to the Mn(II)-Mn(II), which leads to the weakly antiferromagnetic interaction of d5-d5 electrons through superexchange coupling.

Wu, Sangwook; Sim, Sooyeon

2012-01-01

272

Enhanced short-circuit current density in poly(3-hexylthiophene) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 based organic solar cells by doping small molecular perylene  

NASA Astrophysics Data System (ADS)

The authors investigate the effects of a small molecular dye, perylene, on the performance of organic solar cells based on poly(3-hexylthiophene) (P3HT) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 (PCBM) blends. The short-circuit current density is improved, and a maximum 27% enhancement in power conversion efficiency is achieved by doping suitable perylene into P3HT:PCBM blends. It is attributed to be the enhanced absorption of perylene doped P3HT:PCBM blends, which is also confirmed in single-carrier devices. Moreover, the barrier height at the anode/blend is largely lowered from 0.61 eV to 0.28 eV through evaluating temperature dependence of current-voltage characteristics.

Lou, Yanhui; Wang, Zhaokui; Naka, Shigeki; Okada, Hiroyuki

2011-07-01

273

1-[(Cyclo-propyl-meth-oxy)meth-yl]-5-ethyl-6-(4-methyl-benzyl)-1,2,3,4-tetra-hydro-pyrimidine-2,4-dione  

PubMed Central

The pyrimidine ring in the title compound, C19H24N2O3, is nearly planar (r.m.s. deviation = 0.008?); the C atom at the 5-position deviates by 0.054?(3)? from the mean plane and the C atom at the 6-position by 0.006?(3)? in the opposite direction. The benzene ring is approximately perpendicular to the pyrimidine ring [dihedral angle = 83.90?(10)]. The amino group is hydrogen-bond donor to the exocyclic O atom at the 2-position of an adjacent molecule, the hydrogen bond generating an inversion dimer. The cyclopropyl ring is disordered over two sets of sites with the major component having 71.5?(4)% occupancy.

El-Brollosy, Nasser R.; El-Emam, Ali A.; Al-Deeb, Omar A.; Ng, Seik Weng

2012-01-01

274

Drug-Induced Reversible and Irreversible Enzyme Alterations Underlying Drug-Resistance  

Microsoft Academic Search

p-Aminobenzoic acid-dependent M 48-34 strains of Escherichia coli grown with and without sulphathiazole (ST) were investigated with respect to the enhanced capacities they acquire simultaneously for the synthesis of folic acid and resistance. The washed cells of the sensitive strain grown in drug-free media contain a small amount of intracellularly accumulated folic acid precursor(s). The precursors are converted by the

M. G. Sevag; K. Ishii

1958-01-01

275

Semiquantitative determination of water-soluble vitamins by circular thin-layer chromatography  

Microsoft Academic Search

Summary A method for semiquantitative determination of water-soluble vitamins such as thiamin hydrochloride, riboflavin, pyridoxine, choline chloride,p-aminobenzoic acid, cyanocobalamine, nicotinic acid and ascorbic acid is described. It involves making circular spots or rings on chromatoplates using circular thin-layer chromatographic apparatus. The method is based on sensitivity and specificity of spot reactions together with comparison of the color intensity of a

Manzur-ul-Haque Hashmi; Farhat Rafique Chughtai; M. I. D. Chughtai

1969-01-01

276

Structural and Magnetic Effects of meso-Substitution in Alkyl-Substituted Metalloporphyrinate ?-Cation Radicals: Characterization of [Fe-(TalkylP.)(Cl)]SbCl6 (alkyl = ethyl and n-propyl)  

PubMed Central

We report the preparation and characterization of two meso-alkyl substituted porphyrin ?-cation radical derivatives, [Fe(TalkylP.)(Cl)]SbCl6 (alkyl = ethyl or propyl). Both complexes have been characterized by UV/vis/near-IR, IR and Mssbauer spectroscopy, temperature-dependent solid-state magnetic susceptibility measurements and X-ray structure determinations. All data for both oxidized species are consistent with the formulation of the complexes as ring-oxidized iron(III) porphyrin species. The molecular structures of the two five-coordinate species have the typical square-pyramidal coordination group of high-spin iron(III) derivatives. The crystal structures also reveal that the species form cofacial ?? dimers with lateral shifts of 1.44 and 3.22 , respectively, for the propyl and ethyl radical derivatives. Both radicals exhibit porphyrin cores with alternating bond distance patterns in the inner 16-membered ring. In addition, [Fe(TEtP.)(Cl)]SbCl6 and [Fe(TPrP.)(Cl)]SbCl6 have been characterized by temperature-dependent (6300K) magnetic susceptibility studies, the best fitting of the temperature-dependent moments reveal strong coupling between iron spins and porphyrin radical, and a smaller magnitude of antiferromagnetic coupling between ring radicals, which are opposite to those found in the five-coordinate iron(III) OEP radicals. The differences in structure and properties of the cation radical meso-alkyl and ?-alkyl derivatives possibly reflect differences in properties of a 1u- and a 2u-forming radicals.

Li, Ming; Neal, Teresa J.; Wyllie, Graeme R. A.; Schulz, Charles E.; Scheidt, W. Robert

2010-01-01

277

The Role of Excitatory Amino Acids and NMDA Receptors in Traumatic Brain Injury  

NASA Astrophysics Data System (ADS)

Brain injury induced by fluid percussion in rats caused a marked elevation in extracellular glutamate and aspartate adjacent to the trauma site. This increase in excitatory amino acids was related to the severity of the injury and was associated with a reduction in cellular bioenergetic state and intracellular free magnesium. Treatment with the noncompetitive N-methyl-D-aspartate (NMDA) antagonist dextrorphan or the competitive antagonist 3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid limited the resultant neurological dysfunction; dextrorphan treatment also improved the bioenergetic state after trauma and increased the intracellular free magnesium. Thus, excitatory amino acids contribute to delayed tissue damage after brain trauma; NMDA antagonists may be of benefit in treating acute head injury.

Faden, Alan I.; Demediuk, Paul; Panter, S. Scott; Vink, Robert

1989-05-01

278

Pancreatic glucagon secretion and exocrine function (BT-PABA test) in chronic pancreatitis  

Microsoft Academic Search

Plasma concentrations of pancreatic glucagon, C-peptide, and pancreatic polypeptide were measured during arginine stimulation in 16 patients with chronic pancreatitis, in eight subjects with idiopathic diabetes mellitus, and in seven healthy controls. The hormone responses were compared with exocrine pancreatic function as assessed using the urinary excretion rate ofp-aminobenzoic acid after oral ingestion ofn-benzoyl-l-tyrosyl-p-aminobenzoic acid (BT-PABA). The increase in pancreatic

U. Keller; E. Szllsy; L. Varga; K. Gyr

1984-01-01

279

Characterization of a non-ribosomal peptide synthetase-associated diiron arylamine N-oxygenase from Pseudomonas syringae pv. phaseolicola  

Microsoft Academic Search

The regiospecific oxidation of aromatic amines to aryl nitro compounds is critical to the synthesis of several natural products having pharmacological importance. The arylamine N-oxygenase (AAO) from Streptomyces thioluteus (AurF) selectively oxidizes p-aminobenzoic acid to p-nitrobenzoic acid and has been the subject of investigation for its unique chemistry and substrate preferences. Little, however, is known about the biochemistry and substrate

Erin Platter; Michael Lawson; Christopher Marsh; Matthew H. Sazinsky

2011-01-01

280

Gas chromatographic quantification of free D-amino acids in higher vertebrates.  

PubMed

D-amino acids were determined in brain, body fluids (urine, blood coagulate, serum, plasma) and faeces of animals belonging to nine out of 11 taxonomic orders of vertebrates (Artiodactyla, Aves, Carnivora, Lagomorpha, Marsupalia, Osteichthyes, Primates, Rodentia, Tubilidentata). Free amino acids were isolated by means of cation exchangers and converted into volatile N(O)-perfluoroacylamino acid propyl esters. Derivatives of amino acids were separated into D- and L-enantiomers using Chirasil-L-Val capillary columns and detected by selected ion monitoring mass spectrometry. Quantification of amino acids was achieved by comparison of analytes with amino acid standards using L-norleucine as internal standard. Large relative amounts of D-serine were determined in brains of mammals but not of birds. In body fluids the D-enantiomers of most proteinogenic L-amino acids were detected, largest absolute and relative amounts were found in urine. Therein quantities of D-Ala and D-Ser exceeded 50% relative to the L-enantiomers in many instances. Feeding animals with diet fortified with DL-Met resulted in excretion of almost racemic Met in urine. D-Amino acids were also abundant in faeces of rodents. The data confirm that d-amino acids are common in body fluids and certain tissues of vertebrates. PMID:16037932

Ptzold, Ralf; Schieber, Andreas; Brckner, Hans

2005-07-01

281

SIMULTANEOUS DETERMINATION OF P-HYDROXYBENZOIC ACID, 2PHENOXYETHANOL, METHYLPHYDROXYBENZOATE, ETHYL-P-HYDROXYBENZOATE, PROPYLPHYDROXYBENZOATE, ISOBUTYLPHYDROXYBENZOATE, AND N-BUTYL-P-HYDROXYBENZOATE IN SENSELLE LUBRICANT FORMULATION BY HPLC  

Microsoft Academic Search

A new and simple reversed-phase high-performance liquid chromatographic (HPLC) method has been developed and validated for the simultaneous determination of p-hydroxybenzoic acid, 2-phenoxyethanol, methyl-p-hydroxybenzoate, ethyl-p-hydroxybenzoate, propyl-p-hydroxybenzoate, iso-butyl-p-hydroxybenzoate and n-butyl-p-hydroxybenzoate preservatives in senselle lubricant formulation. The seven compounds were separated on a C18 ChromSpher polymeric octadecylsilane (ODS)-encapsulated spherical silica column with acetonitrile-tetrahydrofuran-water, 22:14:64 (v\\/v\\/v) as mobile phase at flow rate of

Ghulam A. Shabir

2011-01-01

282

Effect of Protozoa on Bacterial Degradation of an Aromatic Compound  

PubMed Central

Prototrophic and growth factor-requiring strains of Alcaligenes spp. were used to study the effect of a protozoan, Tetrahymena pyriformis, on the degradation of p-aminobenzoate. The protozoan inhibited activity of the prototrophic bacterium by reducing its population size. For the growth factor-requiring strain of Alcaligenes, T. pyriformis provided the required growth factors so that the predator permitted the bacteria to grow and to continue p-aminobenzoate degradation. T. pyriformis inhibited bacterial activity when the amino acid supply was in excess, but activity of the auxotrophic strain of Alcaligenes was stimulated by the protozoan when the amino acid supply was limiting, although the bacterial population size was reduced by the protozoan.

Huang, Tan-Chi; Chang, Miau-Chan; Alexander, Martin

1981-01-01

283

Mycophenolic Acid  

Center for Drug Evaluation (CDER)

... Publications on Genomics. -. Mycophenolic Acid. Pharmacogenomic Information. ... Mycophenolic Acid, Transplantation, HGPRT, Precautions. ... More results from www.fda.gov/drugs/scienceresearch/researchareas

284

1- or 3-(3-Amino-2-hydroxy-1-phenyl propyl)-1,3-dihydro-2H-benzimidazol-2-ones: potent, selective, and orally efficacious norepinephrine reuptake inhibitors.  

PubMed

Sequential structural modifications of the aryloxypropanamine template (e.g., atomoxetine, 2) led to a novel series of 1-(3-amino-2-hydroxy-1-phenyl propyl)-1,3-dihydro-2H-benzimidazol-2-ones as selective norepinephrine reuptake inhibitors (NRIs). In general, this series of compounds potently blocked the human norepinephrine transporter (hNET) while exhibiting selectivity at hNET against both the human serotonin (hSERT) and dopamine transporters (hDAT). Numerous compounds (e.g., 19-22) had low nonamolar hNET potency with IC(50) values of 7-10 nM and excellent selectivity (>500 fold) at hNET over hSERT and hDAT. Several compounds, such as 20 and 22, were tested in a telemetric rat model of ovariectomized-induced thermoregulatory dysfunction and were efficacious at oral doses of 3 mg/kg in reducing the tail skin temperature. In addition, compound 20 was also studied in the rat hot plate and spinal nerve ligation (SNL) models of acute and neuropathic pain, respectively, and was orally efficacious at doses of 3-10 mg/kg. PMID:19722525

Zhang, Puwen; Terefenko, Eugene A; Bray, Jenifer; Deecher, Darlene; Fensome, Andrew; Harrison, Jim; Kim, Callain; Koury, Elizabeth; Mark, Lilly; McComas, Casey C; Mugford, Cheryl A; Trybulski, Eugene J; Vu, An T; Whiteside, Garth T; Mahaney, Paige E

2009-09-24

285

Fluorescent derivatives of ? receptor ligand 1-cyclohexyl-4-[3-(5-methoxy-1,2,3,4-tetrahydronaphthalen-1-yl)propyl]piperazine (PB28) as a tool for uptake and cellular localization studies in pancreatic tumor cells.  

PubMed

Fluorescent derivatives of ?(2) high affinity ligand 1-cyclohexyl-4-[3-(5-methoxy-1,2,3,4-tetrahydronaphthalen-1-yl)propyl]piperazine 1 (PB28) were synthesized. NBD or dansyl fluorescent tags were connected through a 5- or 6-atom linker in two diverse positions of 1 structure. Good ?(2) affinities were obtained when the fluorescent tag was linked to 5-methoxytetralin nucleus replacing the methyl function. NBD-bearing compound 16 displayed high ?(2) affinity (K(i) = 10.8 nM) and optimal fluorescent properties. Its uptake in pancreatic tumor cells was evaluated by flow cytometry, showing that it partially occurs through endocytosis. In proliferating cells, the uptake was higher supporting that ?(2) receptors are markers of cell proliferation and that the higher the proliferation is, the stronger the antiproliferative effect of ?(2) agonists is. Colocalization of 16 with subcellular organelles was studied by confocal microscopy: the greatest was in endoplasmic reticulum and lysosomes. Fluorescent ?(2) ligands show their potential in clarifying the mechanisms of action of ?(2) receptors. PMID:21744858

Abate, Carmen; Hornick, John R; Spitzer, Dirk; Hawkins, William G; Niso, Mauro; Perrone, Roberto; Berardi, Francesco

2011-07-20

286

Synthesis and crystal structure of binuclear copper(II) complex bridged by N-(2-hydroxyphenyl)-N'-[3-(diethylamino)propyl]oxamide: in vitro anticancer activity and reactivity toward DNA and protein.  

PubMed

A new oxamido-bridged bicopper(II) complex, [Cu2(pdpox)(bpy)(CH3OH)](ClO4), where H3pdpox and bpy stand for N-(2-hydroxyphenyl)-N'-[3-(diethylamino)propyl]oxamide and 2,2'-bipyridine, respectively, has been synthesized and characterized by elemental analyses, molar conductivity measurements, infrared and electronic spectra studies, and X-ray single crystal diffraction. In the crystal structure, the pdpox(3-) ligand bridges two copper(II) ions as cisoid conformation. The inner copper(II) ion has a {N3O} square-planar coordination geometry, while the exo- one is in a {N2O3} square-pyramidal environment. There are two sets of interpenetrating two-dimensional hydrogen bonding networks parallel to the planes (2 1 0) and (210), respectively, to form a three-dimensional supramolecular structure. The bicopper(II) complex exhibits cytotoxic activity against the SMMC7721 and A549 cell lines. The reactivity toward herring sperm DNA and bovine serum albumin revealed that the bicopper(II) complex can interact with the DNA by intercalation mode, and the complex binds to protein BSA responsible for quenching of tryptophan fluorescence by static quenching mechanism. PMID:23780852

Gao, Yang; Li, Yan-Tuan; Wu, Zhi-Yong; Yan, Cui-Wei

2013-06-18

287

Hexa-kis-(propyl-ammonium) benzene-1,2,4,5-tetra-carboxyl-ate 2,5-dicarb-oxy-benzene-1,4-carboxyl-ate tetra-hydrate  

PubMed Central

The title organic salt, 6C3H10N+C10H2O8 4?C10H4O8 2?4H2O, contains seven independent entities in the asymmetric unit which comprises three propylammonium cations, two water molecules, half a 2,5-dicarboxybenzene-1,4-carboxylate dianion (H2btc2?) and half a benzene-1,2,4,5-tetracarboxylate tetraanion (btc4?), the latter two anions being located about centres of inversion. One of the water molecules is disordered over two positions in a 0.55?(2):0.45?(2) ratio. The combination of molecular ions and water molecules results in an extensive and complex three-dimensional network of hydrogen bonds, the network being made up of nine unique NH?O interactions between the ammonium cations and the anions, as well as four unique OH?O interactions between the water molecules and the anions.

Khorasani, Sanaz; Fernandes, Manuel A.

2012-01-01

288

Identification and characterization of N-acetylcysteine conjugates of valproic acid in humans and animals.  

PubMed

Reactive and hepatotoxic metabolites formed from the biotransformation of valproic acid (VPA) are normally detoxified by conjugating with GSH and followed by mercapturic acid metabolism to produce their respective N-acetylcysteine (NAC) conjugates. Hence, the levels of NAC conjugates of VPA in human urine are an indirect measure of exposure of the liver toward reactive metabolites of the anticonvulsant drug. We report here the synthesis, identification, and characterization of a second NAC conjugate of (E)-2-propyl-2, 4-pentadienoic acid in the urine samples (n = 39) of humans on VPA therapy, namely, (E)-5-(N-acetylcystein-S-yl)-2-ene VPA by gas chromatography/mass spectrometry and liquid chromatography with tandem mass spectrometry. In this study, we were able to separate the diastereomers of (E)-5-(N-acetylcystein-S-yl)-3-ene VPA by HPLC. The NAC conjugate of 4,5-epoxy VPA, namely, 5-NAC-4-OH-VPA gamma-lactone, previously identified in rats treated with 2-propyl-4-pentenoic acid (4-ene VPA), was not detected in any of the human urine samples studied. This suggests that in humans, the P-450 metabolism of 4-ene VPA to the reactive epoxide is not a significant pathway. The excretion of the NAC conjugate of (E)-2, 4-diene VPA glucuronide in the urine of seven patients on VPA was also examined and was not detected. The limit of detection of 5-NAC-3-keto VPA and its decarboxylated product, 1-NAC-3-heptanone, was estimated at 25 ng (signal to noise ratio > 3). Neither 5-NAC-3-keto VPA nor 1-NAC-3-heptanone was detected in the urine of patients on VPA therapy or 4-ene VPA-treated guinea pigs, but 1-NAC-3-heptanone was detected in the urine of 4-ene VPA-treated rats. PMID:10859157

Gopaul, S V; Farrell, K; Abbott, F S

2000-07-01

289

Synthesis and pharmacological profile of a new selective G protein-coupled receptor 119 agonist; 6-((2-fluoro-3-(1-(3-isopropyl-1,2,4-oxadiazol-5-yl)piperidin-4-yl)propyl)amino)-2,3-dihydro-1H-inden-1-one.  

PubMed

6-((2-Fluoro-3-(1-(3-isopropyl-1,2,4-oxadiazol-5-yl)piperidin-4-yl)propyl)amino)-2,3-dihydro-1H-inden-1-one is a potent drug-like G protein-coupled receptor 119 (GPR119) agonist. It is hoped that this compound would be instrumental in probing the pharmacological potential of GPR119 agonists. PMID:22976315

Sakairi, Masao; Kogami, Masakazu; Torii, Masafumi; Makino, Mitsuhiro; Kataoka, Daisuke; Okamoto, Ryuji; Miyazawa, Toshiyuki; Inoue, Megumi; Takahashi, Naoki; Harada, Satoko; Watanabe, Nobuhide

2012-01-01

290

Coordination geometries of bis(4-amino-3-alkyl-1,2,4-triazole-5-thione) complexes of first-row transition metals: crystal structures of complexes with propyl and hydrogen in the 3-position. Relationship to the 3-methyl and 3-ethyl analogs  

Microsoft Academic Search

A series of bis bidentate complexes of 4-amino-3-propyl-1,2,4-triazole-5-thione, SN4C5H10 (apt, 1) of the divalent ions Fe, Co, Ni, and Zn has been crystallized by direct combination of the ligand and metal nitrate or perchlorate hydrate salt in ethanol. The structures were determined by single-crystal X-ray diffraction techniques. In all the complexes, the triazole bonds to the metal ion through the

Robert M McCarrick; Martin J Eltzroth; Philip J Squattrito

2000-01-01

291

Structures of asparagine-linked oligosaccharides from hen egg-yolk antibody (IgY). Occurrence of unusual glucosylated oligo-mannose type oligosaccharides in a mature glycoprotein  

Microsoft Academic Search

Asparagine-linked oligosaccharides present on hen egg-yolk immunoglobulin, termed IgY, were liberated from the protein by hydrazinolysis. AfterN-acetylation, the oligosaccharides were labelled with a UV-absorbing compound,p-aminobenzoic acid ethyl ester (ABEE). The ABEE-derivatized oligosaccharides were fractionated by anion exchange, normal phase and reversed phase HPLC, and their structures were determined by a combination of sugar composition analysis, methylation analysis, negative ion FAB-MS,

Masaya Ohta; Jiharu Hamako; Satoru Yamamoto; Hajime Hatta; Mujo Kim; Takehiko Yamamoto; Satoru Oka; Tsuguo Mizuochi; Fumito Matsuura

1991-01-01

292

Do we eat less fat, or just report so?  

Microsoft Academic Search

OBJECTIVE: To examine secular trends in diet reporting error.METHODS: Dietary information was obtained from 228 Danish men and women in 198788, and from 122 men and women in 199394.RESULTS: Bias in dietary reporting of energy and protein intake was assessed by comparing reported intake with intake data, estimated from 24 h nitrogen output, validated by administering P-aminobenzoic acid, and estimated

BL Heitmann; L Lissner; M Osler

2000-01-01

293

Folate synthesized by bacteria in the human upper small intestine is assimilated by the host  

Microsoft Academic Search

BACKGROUND & AIMS: Some intestinal flora are known to synthesize folate. The aim of this study was to determine whether folate synthesized by small intestinal flora is assimilated by the human host. METHODS: Subjects with atrophic gastritis and healthy volunteers were studied before and after omeprazole administration. A double-lumen perfusion tube was placed in the duodenum. 3H-labeled P-aminobenzoic acid, a

E Camilo; J Zimmerman; JB Mason; B Golner; R Russell; J Selhub; IH Rosenberg

1996-01-01

294

Accommodation of Mn II, Mn IIIN, O, O, O-donor Schiff base complexes in zeolite-Y: Synthesis, structural studies and CO adsorption  

Microsoft Academic Search

Manganese (II)-, (III)-complexes with NO3 Schiff base ligand (SPAB) derived from salicylaldehyde and p-aminobenzoic acid have been synthesized and immobilized in the zeolite-Y supercages by a flexible ligand method. The synthesized new host\\/guest materials have been characterized by various physicochemical techniques, in addition to surface area measurements and nitrogen adsorption studies. Investigation of the stereochemistry of these incorporated chelates elucidated

Ayman H. Ahmed; Zeinhom M. El-Bahy; Tarek M. Salama

2010-01-01

295

Salt intake in young Swedish men  

Microsoft Academic Search

Objective: To measure dietary salt intake in a Swedish population. Design: A cross-sectional study with measured 24 h urinary excretion of Na and K. Completeness of urine collection was assessed using p-aminobenzoic acid. The subjects were interviewed on their habitual food intake. Setting: Sahlgrenska University Hospital, Gothenburg, Sweden. Subjects: Eighty-six young men (age 18-20 years), randomly selected from the population

L Hulthn; M Aurell; S Klingberg; E Hallenberg; M Lorentzon; C Ohlsson

2010-01-01

296

Acid rain  

Microsoft Academic Search

Acid precipitation is a global problem. The effects were first seen in Europe; it affects the Great Lakes and the Midwest because higher-than-normal levels of acidity in rain are found in these areas. Several bays of the Great Lakes are now known to receive substantial runoff from freshwater streams that have been made acidic by acid rains. These areas may

1979-01-01

297

Simultaneous determination of trace levels of ethylmercury and methylmercury in biological samples and vaccines using sodium tetra(n-propyl)borate as derivatizing agent.  

PubMed

Because of increasing awareness of the potential neurotoxicity of even low levels of organomercury compounds, analytical techniques are required for determination of low concentrations of ethylmercury (EtHg) and methylmercury (MeHg) in biological samples. An accurate and sensitive method has been developed for simultaneous determination of methylmercury and ethylmercury in vaccines and biological samples. MeHg and EtHg were isolated by acid leaching (H2SO4-KBr-CuSO4), extraction of MeHg and EtHg bromides into an organic solvent (CH2Cl2), then back-extraction into Milli-Q water. MeHg and EtHg bromides were derivatized with sodium tetrapropylborate (NaBPr4), collected at room temperature on Tenax, separated by isothermal gas chromatography (GC), pyrolysed, and detected by cold-vapour atomic fluorescence spectrometry (CV AFS). The repeatability of results from the method was approximately 5-10% for EtHg and 5-15% for MeHg. Detection limits achieved were 0.01 ng g-1 for EtHg and MeHg in blood, saliva, and vaccines and 5 ng g-1 for EtHg and MeHg in hair. The method presented has been shown to be suitable for determination of background levels of these contaminants in biological samples and can be used in studies related to the health effects of mercury and its species in man. This work illustrates the possibility of using hair and blood as potential biomarkers of exposure to thiomersal. PMID:17340078

Gibicar, Darija; Logar, Martina; Horvat, Nusa; Marn-Pernat, Andreja; Ponikvar, Rafael; Horvat, Milena

2007-03-06

298

Synthesis, characterization and anti proliferative effect of [Au(en) 2]Cl 3 and [Au(N- propyl-en) 2]Cl 3 on human cancer cell lines  

NASA Astrophysics Data System (ADS)

Two Au(III) complexes of the type [Au(en) 2]Cl 3 ( 2a) and [Au(N-pr-en) 2]Cl 3 ( 3a) were synthesized by reacting Auric acid (HAuCl 43H 2O) with 2 equiv. ethylenediamine (en) or N-alkyl substituted ethylenediamine ligands. This metallodrug was characterized by various analytical and spectroscopic techniques such as elemental analysis, UV-Vis, Far-IR, 1H NMR and solution 13C as well as solid 13C and 15N NMR. Potentiality of [Au(en) 2]Cl 3 and [Au(N-pr-en) 2]Cl 3 as an anti-cancer agent were investigated by measuring some relevant physicochemical and biochemical properties such as stability of Au-N bonds by vibrational stretching from Far IR as well as cytotoxicity and stomach cancer cell inhibiting effect, respectively. The solid-state 15N NMR chemical shift shows that the ligand is strongly bound to gold(III) centre via N atoms. The computational study of 2a shows that the gold coordination sphere adopts distorted square planar geometry with bidentate ethylenediamine ligands acting as a tetradentate chelate. While stable in the solution state, the in vitro biological studies performed with these compounds 2a in solution showed higher activity towards the inhibitory effects of the human cancer cell lines such as prostate cancer (PC-3) and gastric carcinoma (SGC-7901) than that of the N-substituted gold(III) complex ( 3a). Cytotoxicity of the new compounds has also been estimated in PC-3 and SGC-7901 cells.

Isab, Anvarhusein A.; Shaikh, M. Nasiruzzaman; Monim-ul-Mehboob, M.; Al-Maythalony, Bassem A.; Wazeer, Mohammed I. M.; Altuwaijri, Saleh

2011-09-01

299

Synthesis, metabolic stability and antiviral evaluation of various alkoxyalkyl esters of cidofovir and 9-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]adenine.  

PubMed

Alkoxyalkyl esters of cidofovir (CDV) are orally active agents which inhibit the replication of a variety of double stranded DNA (dsDNA) viruses including variola, vaccinia, ectromelia, herpes simplex virus, cytomegalovirus, adenovirus and others. One of these compounds, hexadecyloxypropyl-CDV (HDP-CDV, CMX001) is in clinical development for prevention and treatment of poxvirus infection, vaccination complications, and for infections caused by cytomegalovirus, adenovirus, herpesviruses and other dsDNA viruses. This class of lipid analogs is potentially prone to undergo omega oxidation of the alkyl moiety which can lead to a short chain carboxylic acid lacking antiviral activity. To address this issue, we synthesized a series of alkoxyalkyl or alkyl glycerol esters of CDV and (S)-HPMPA having modifications in the structure of the alkyl residue. Antiviral activity was assessed in cells infected with vaccinia, cowpox or ectromelia viruses. Metabolic stability was determined in S9 membrane fractions from rat, guinea pig, monkey and human liver. All compounds had substantial antiviral activity in cells infected with vaccinia, cowpox or ectromelia. Metabolic stability was lowest in monkey liver S9 incubations where rapid disappearance of HDP-CDV and HDP-(S)-HPMPA was noted. Metabolic stability in monkey preparations increased substantially when a ?-1 methyl group (15-methyl-HDP-CDV) or a terminal cyclopropyl residue (14-cyclopropyl-tetradecyloxypropyl-CDV) was present in the alkyl chain. The most stable compound was 1-O-octadecyl-2-O-benzyl-sn-glycero-3-CDV (ODBG-CDV) which was not metabolized extensively by monkey liver S9. In rat, guinea pig or human liver S9 incubations, most of the modified antiviral compounds were considerably more stable. PMID:21493074

Ruiz, Jacqueline; Beadle, James R; Buller, R Mark; Schreiwer, Jill; Prichard, Mark N; Keith, Kathy A; Lewis, Kenneth C; Hostetler, Karl Y

2011-03-23

300

Identification of the Biotransformation Products of 2-Ethylhexyl 4-(N,N-Dimethylamino)benzoate.  

PubMed

Nowadays, 2-ethylhexyl 4-(N,N-dimethylamino)benzoate (EDP) is one of the most widely used UV filters in sunscreen cosmetics and other cosmetic products. However, undesirable processes such as percutaneous absorption and biological activity have been attributed to this compound. The in vitro metabolism of EDP was elucidated in the present work. First of all, the phase I biotransformation was studied in rat liver microsomes and two metabolites, N,N-dimethyl-p-aminobenzoic acid (DMP) and N-monomethyl-p-aminobenzoic acid (MMP), were identified by GC-MS analysis. Secondly, the phase II metabolism was investigated by means of LC-MS. The investigated reactions were acetylation and glucuronidation working with rat liver cytosol and with both human and rat liver microsomes, respectively. Analogue studies with p-aminobenzoic acid (PABA) were carried out in order to compare the well established metabolic pathway of PABA with the unknown biotransformation of EDP. In addition, a method for the determination of EDP and its two phase I metabolites in human urine was developed. The methodology requires a solid-phase extraction prior to LC-MS analysis. The method is based on standard addition quantification and has been fully validated. The repeatability of the method, expressed as relative standard deviation, was in the range 3.4-7.4% and the limit of detection for all quantified analytes was in the low ng mL(-1) range. PMID:20062819

Len, Zacarias; de Vlieger, Jon; Chisvert, Alberto; Salvador, Amparo; Lingeman, Henk; Irth, Hubertus; Giera, Martin

2009-11-12

301

Interaction of cyanine dyes with nucleic acids. XVII. Towards an aggregation of cyanine dyes in solutions as a factor facilitating nucleic acid detection  

Microsoft Academic Search

Spectral properties of newly synthesized cyanine dyes, namely 1-[6-(4-{6-[2,6-dimethyl-4-(3-methyl-2,3-dihydro-1,3-benzothiazol-2-ylidenmethyl)-1-pyridiniumyl]hexanoyl}piperazino)-6-oxohexyl]-2,6-dimethyl-4-(3-ethyl-2,3-dihydro-1,3-benzothiazol-2-ylidenmethyl)pyridinium (K-6) (bichromophoric dye) and 1-[5-di(3-{5-[2,6-dimethyl-4-(3-methyl-2,3-dihydro-1,3-benzothiazol-2-ylidenmethyl)-1-pyridiniumyl]pentylcarboxamido}propyl) carbamoylpentyl]-2,6-dimethyl-4-(3-methyl-2,3-dihydro-1,3-benzothiazol-2-ylidenmethyl) pyridinium (K-T) (trichromophoric dye) in solutions in the presence of and without deoxyribonucleic acid (DNA) were studied within a wide concentration range. It has been established that absorption, as well as fluorescence of investigated dye solutions, without DNA are mainly determined by H-aggregates of dye

T. Yu Ogulchansky; V. M Yashchuk; M. Yu Losytskyy; I. O Kocheshev; S. M Yarmoluk

2000-01-01

302

Bis(propyl)-cognitin protects against glutamate-induced neuro-excitotoxicity via concurrent regulation of NO, MAPK/ERK and PI3-K/Akt/GSK3? pathways.  

PubMed

We have previously reported that bis(propyl)-cognitin (B3C), similar to memantine (MEM), is an uncompetitive N-methyl-d-aspartate receptor antagonist with fast off-rate property. In the current study, we further demonstrated that in primary cultures of rat cerebellar granule neurons (CGNs), 2h pretreatment of B3C (IC50, 0.45?M) prevented glutamate-induced excitotoxicity 10 times more potently than memantine (IC50, 4.58 ?M), as evidenced by cell viability and lactate dehydrogenase release assays. Additionally, B3C pretreatment could inhibit the increase of intracellular nitric oxide (NO) and the activation of phosphorylated ERK, and reverse the suppression of phosphorylated Akt and GSK3? caused by glutamate. Furthermore, the neuroprotection of B3C was abolished by phosphatidylinositol 3-kinase (PI3-K) inhibitor LY294002. Meanwhile, pharmacological inhibition showed that neither the single specific inhibitors of nitric oxide synthase (L-NMMA), MEK1/2 (U0126) and GSK3? (SB415286 and LiCl) nor the combinations of any two of them could fully protect against glutamate-induced apoptosis. However, the co-application of these three inhibitors produced nearly 100% inhibition of glutamate-induced apoptosis. These results taken together suggest that B3C elicits neuroprotection against glutamate-induced neurotoxicity in CGNs via concurrent inhibition of NO, MAPK/ERK pathways and activation of PI3-K/Akt/GSK3? pathway. Combining these and our previous publications, it is conjectured that the dimer might be an ideal candidate drug in delaying the course of neurodegeneration related with Alzheimer's disease. PMID:23357479

Hu, Shengquan; Cui, Wei; Mak, Shinghung; Tang, Jing; Choi, Chunglit; Pang, Yuanping; Han, Yifan

2013-01-26

303

Studies on the translational and rotational motions of ionic liquids composed of N-methyl-N-propyl-pyrrolidinium (P13) cation and bis(trifluoromethanesulfonyl)amide and bis(fluorosulfonyl)amide anions and their binary systems including lithium salts.  

PubMed

Room-temperature ionic liquids (RTIL, IL) are stable liquids composed of anions and cations. N-methyl-N-propyl-pyrrolidinium (P(13), Py(13), PYR(13), or mppy) is an important cation and produces stable ILs with various anions. In this study two amide-type anions, bis(trifluoromethanesulfonyl)amide [N(SO(2)CF(3))(2), TFSA, TFSI, NTf(2), or Tf(2)N] and bis(fluorosulfonyl)amide [N(SO(2)F)(2), FSA, or FSI], were investigated. In addition to P(13)-TFSA and P(13)-FSA, lithium salt doped samples were prepared (P(13)-TFSA-Li and P(13)-FSA-Li). The individual ion diffusion coefficients (D) and spin-lattice relaxation times (T(1)) were measured by (1)H, (19)F, and (7)Li NMR. At the same time, the ionic conductivity (?), viscosity (?), and density (?) were measured over a wide temperature range. The van der Waals volumes of P(13), TFSA, FSA, Li(TFSA)(2), and Li(FSA)(3) were estimated by molecular orbital calculations. The experimental values obtained in this study were analyzed by the classical Stokes-Einstein, Nernst-Einstein (NE), and Stokes-Einstein-Debye equations and Walden plots were also made for the neat and binary ILs to clarify physical and mobile properties of individual ions. From the temperature-dependent velocity correlation coefficients for neat P(13)-TFSA and P(13)-FSA, the NE parameter 1-? was evaluated. The ionicity (electrochemical molar conductivity divided by the NE conductivity from NMR) and the 1-? had exactly the same values. The rotational and translational motions of P(13) and jump of a lithium ion are also discussed. PMID:21090866

Hayamizu, Kikuko; Tsuzuki, Seiji; Seki, Shiro; Fujii, Kenta; Suenaga, Masahiko; Umebayashi, Yasuhiro

2010-11-21

304

Studies on the translational and rotational motions of ionic liquids composed of N-methyl-N-propyl-pyrrolidinium (P13) cation and bis(trifluoromethanesulfonyl)amide and bis(fluorosulfonyl)amide anions and their binary systems including lithium salts  

NASA Astrophysics Data System (ADS)

Room-temperature ionic liquids (RTIL, IL) are stable liquids composed of anions and cations. N-methyl-N-propyl-pyrrolidinium (P13, Py13, PYR13, or mppy) is an important cation and produces stable ILs with various anions. In this study two amide-type anions, bis(trifluoromethanesulfonyl)amide [N(SO2CF3)2, TFSA, TFSI, NTf2, or Tf2N] and bis(fluorosulfonyl)amide [N(SO2F)2, FSA, or FSI], were investigated. In addition to P13-TFSA and P13-FSA, lithium salt doped samples were prepared (P13-TFSA-Li and P13-FSA-Li). The individual ion diffusion coefficients (D) and spin-lattice relaxation times (T1) were measured by 1H, 19F, and 7Li NMR. At the same time, the ionic conductivity (?), viscosity (?), and density (?) were measured over a wide temperature range. The van der Waals volumes of P13, TFSA, FSA, Li(TFSA)2, and Li(FSA)3 were estimated by molecular orbital calculations. The experimental values obtained in this study were analyzed by the classical Stokes-Einstein, Nernst-Einstein (NE), and Stokes-Einstein-Debye equations and Walden plots were also made for the neat and binary ILs to clarify physical and mobile properties of individual ions. From the temperature-dependent velocity correlation coefficients for neat P13-TFSA and P13-FSA, the NE parameter 1-? was evaluated. The ionicity (electrochemical molar conductivity divided by the NE conductivity from NMR) and the 1-? had exactly the same values. The rotational and translational motions of P13 and jump of a lithium ion are also discussed.

Hayamizu, Kikuko; Tsuzuki, Seiji; Seki, Shiro; Fujii, Kenta; Suenaga, Masahiko; Umebayashi, Yasuhiro

2010-11-01

305

Isolation and characterization of a cell line resistant to 5-[3-(2-nitro-1-imidazoyl)-propyl]-phenanthridinium bromide (2-NLP-3), a DNA-intercalating hypoxic cell radiosensitizer and cytotoxin.  

PubMed

A DNA-targeted hypoxic cell radiosensitizer and cytotoxin, 5-[3-(2-nitro-1-imidazoyl)-propyl]-phenanthridinium bromide (2-NLP-3), has been shown previously to have increased efficacy over untargeted analogues in vitro. To further study the mechanism of action of this compound, a cell line, CHO-1000, derived from Chinese hamster ovary (CHO) AA8-4 cells was isolated. This cell line is capable of continuously growing in a concentration of 2-NLP-3 approximately 10-fold greater than that tolerated by wild-type CHO cells. The resistance of CHO-1000 to 2-NLP-3 was compared with that of the P-glycoprotein overexpressing, multidrug resistant Chinese hamster cell line CHR-C5 (C5). The resistance of CHO-1000 cells to the acute toxic effects of 2-NLP-3 under both hypoxic and aerobic exposure conditions was intermediate to that of the sensitive CHO wild-type cells and the resistant C5 cells. A similar pattern was seen for the hypoxic cell radiosensitizing ability of 2-NLP-3. 2-NLP-3 produced significant depletion of glutathione under both hypoxic and aerobic conditions in all three cell lines studied, and the degree of depletion was correlated with drug toxicity. CHO-1000 and C5 cells were significantly more resistant to colchicine and doxorubicin compared with wild-type cells. The toxicity pattern of 2-NLP-3 and its comparison phenanthridinium ion, P3, was not the same for CHO-1000 cells compared with C5 cells. Verapamil was an effective agent for reversing the hypoxic resistance to 2-NLP-3 in both CHO-1000 and C5 cells, but only a partial reversal of aerobic resistance was observed in CHO-1000 cells. These results indicate that the resistant phenotype of CHO-1000 is mediated to some degree by P-glycoprotein expression, but that other as yet unidentified factors are also involved. PMID:7605346

Cowan, D S; McClelland, R A; Rauth, A M

1995-06-29

306

Acid rain  

SciTech Connect

A series of definitions for the field of acid rain studies are presented. Protocols for acid rain sampling and monitoring are also presented. A procedure for calculatory precipitation pH is discussed. 11 references, 1 table.

Stensland, G.J.

1983-11-01

307

Oleanolic acid.  

PubMed

Oleanolic acid (3?-hydroxyolean-12-en-28-oic acid) is a pentacyclic triterpenoid compound with a widespread occurrence throughout the plant kingdom. In nature, the compound exists either as a free acid or as an aglycone precursor for triterpenoid saponins, in which it can be linked to one or more sugar chains. Oleanolic acid and its derivatives possess several promising pharmacological activities, such as hepatoprotective effects, and anti-inflammatory, antioxidant, or anticancer activities. With the recent elucidation of its biosynthesis and the imminent commercialization of the first oleanolic acid-derived drug, the compound promises to remain important for various studies. In this review, the recent progress in understanding the oleanolic acid biosynthesis and its pharmacology are discussed. Furthermore, the importance and potential application of synthetic oleanolic acid derivatives are highlighted, and research perspectives on oleanolic acid are given. PMID:22377690

Pollier, Jacob; Goossens, Alain

2012-02-28

308

Aminocaproic Acid  

MedlinePLUS

Aminocaproic acid is used to control bleeding that occurs when blood clots are broken down too quickly. This type ... the baby is ready to be born). Aminocaproic acid is also used to control bleeding in the ...

309

Ethacrynic Acid  

MedlinePLUS

Ethacrynic acid, a 'water pill,' is used to treat swelling and fluid retention caused by various medical problems. It ... Ethacrynic acid comes as a tablet to take by mouth. It is usually taken once or twice a day ...

310

Acid Reflux  

MedlinePLUS

... end of the esophagus called the lower esophageal sphincter or LES keeps the acid in the stomach ... moderately symptomatic GERD. These drugs increase lower esophageal sphincter pressure, which helps prevent acid reflux, and improves ...

311

Acidizing method  

SciTech Connect

A method is described for acidizing a subterranean formation, comprising the steps of: (a) forming an acidizing composition by mixing an aqueous acid component with at least one water-soluble organosilicon compound; and (b) injecting the composition into the formation.

Watkins, D.R.; Kalfayan, L.J.; Hewgill, G.S.

1987-03-03

312

Organic-Inorganic Hybrid Materials Based on the Incorporation of Polysilicic Acid Nanoparticle (PN) with Organic Polymers. 3. Shrinkage Characteristics in the Cure of Unsaturated Polyester Resin in the Presence of a Modified PN  

Microsoft Academic Search

The polysilicic acid nanoparticle (PN) was modified by the reaction of silanol group on its surface with silyl group (Si(OR)3) containing modifiers such as phenyltrimethoxylsilane (PTS), 2-(p-styryl)ethyltrimethoxylsilane (SETS), and 3-(trimethoxylsilyl)propyl methacrylate (TPMA), respectively, to afford modified PNs (M-PNs) including P-PN, S-PN, and T-PN. P-PN, S-PN and T-PN were mixed, respectively, with unsaturated polyester resin (UP) in styrene, UP\\/St, and then

Y. G. Hsu; C. P. Wang

2003-01-01

313

Condensation of the isoprenoid and amino precursors in the biosynthesis of domoic acid.  

PubMed

Understanding how environmental signals regulate production of domoic acid in blooms of Pseudo-nitzschia spp. at a molecular level requires description of the biochemical pathway to this kainoid neurotoxin. Precursor feeding studies have suggested domoic acid arises from the condensation of the C(10) isoprenoid geranyl diphosphate with glutamate, but the specific reactions leading to domoic acid from these precursors remain undescribed. Here, we develop a method to derivatize domoic acid with propyl chloroformate that enables gas chromatography-mass spectrometry (GC-MS) analysis to measure incorporation of stable isotopes into domoic acid generated in cultures incubated with isotopically-labeled substrates. We apply this method to demonstrate that both (2)H from [1-(2)H(2)]geraniol are incorporated into domoic acid, suggesting that the condensation of geranyl diphosphate with an amino group occurs by nucleophilic substitution of the diphosphate rather than by oxidation of geraniol to the aldehyde before reaction with an amino group to form an imine. Ultimately, these and similar studies will facilitate the identification of DA biosynthetic enzymes and genes which will enable the study of how environmental factors regulate DA biosynthesis at the molecular level. PMID:22041653

Savage, Thomas J; Smith, G Jason; Clark, Amy T; Saucedo, Portia N

2011-10-25

314

Synthesis and evaluation of novel bifunctional chelating agents based on 1,4,7,10-tetraazacyclododecane- N, N?, N?, N?-tetraacetic acid for radiolabeling proteins  

Microsoft Academic Search

Detailed synthesis of the bifunctional chelating agents 2-methyl-6-(p-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (1B4M-DOTA) and 2-(p-isothiocyanatobenzyl)-5, 6-cyclohexano-1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetate (CHX-DOTA) are reported. These chelating agents were compared to 2-(p-isothiocyanatobenzyl)-1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid (C-DOTA) and 1, 4, 7, 10-Tetraaza-N-(1-carboxy-3-(4-nitrophenyl)propyl)-N?, N?, N?-tris(acetic acid) cyclododecane (PA-DOTA) as their 177Lu radiolabeled conjugates with Herceptin. In vitro stability of the immunoconjugates

L. L Chappell; D Ma; D. E Milenic; K Garmestani; V Venditto; M. P Beitzel; M. W Brechbiel

2003-01-01

315

Synthesis, characterization and physicochemical properties of oleic acid ether derivatives as biolubricant basestocks.  

PubMed

Petroleum is a finite source as well as causing several environmental problems. Therefore petroleum needs to be replaced by alternative and sustainable sources. Plant oils and oleochemicals derived from them represent such alternative sources; the use of oleochemicals as biobased lubricants is of significant interest. This article presents a series of chemical modification on oleic acid to yield synthetic biolubricant basestocks. Measuring of density, volatility, cloud point (CP), pour point (PP), flash point (FP), viscosity index (VI), onset temperature (OT) and signal maximum temperature (SMT) was carried out for each compound. Furthermore, the friction and wear properties were measured using high-frequency reciprocating rig (HFRR). The results showed that octadecyl 9-octadecyloxy-10-hydroxyoctadecanoate exhibited the most favorable low-temperature performance (CP %ndash;26C, PP %ndash;28C) and the lowest ball wear scan diameter (42 m) while propyl 9-propyloxy-10-hydroxyoctadecanoate exhibited the higher oxidation stability (OT 156C). PMID:22123242

Salimon, Jumat; Salih, Nadia; Yousif, Emad

2011-01-01

316

Synthesis of carboxylic acids, esters, alcohols and ethers containing a tetrahydropyran ring derived from 6-methyl-5-hepten-2-one.  

PubMed

3-hydroxy acids, 3-hydroxy-3,7-dimethyloct-6-enoic acid (1) and 3-hydroxy-2,2,3,7-tetramethyloct-6-enoic acid (2), were prepared from 6-methyl-5-hepten-2-one, and they were subsequently used to prepare (2,6,6-trimethyltetrahydropyran-2-yl)acetic acid (3) and 2-methyl-2-(2,6,6-trimethyltetrahydropyran-2-yl)propanoic acid (4), respectively, via cyclization with an acidic catalyst such as boron trifluoride diethyl etherate or iodine. The reaction of carboxylic acids 3 and 4 with alcohols, including methanol, ethanol, and 1-propanol, produced the corresponding methyl, ethyl, and propyl esters, which all contained a tetrahydropyran ring. Reduction of carboxylic acids 3 and 4 afforded the corresponding alcohols. Subsequent reactions of these alcohols with several acyl chlorides produced novel esters. The alcohols also reacted with methyl iodide and sodium hydride to provide novel ethers. A one-pot cyclization-esterification of 1 to produce esters containing a tetrahydropyran ring, using iodine as a catalyst, was also investigated. PMID:23138252

Hanzawa, Yohko; Hashimoto, Kahoko; Kasashima, Yoshio; Takahashi, Yoshiko; Mino, Takashi; Sakamoto, Masami; Fujita, Tsutomu

2012-01-01

317

E-p-Methoxycinnamic acid protects cultured neuronal cells against neurotoxicity induced by glutamate  

PubMed Central

We previously reported that four new phenylpropanoid glycosides and six known cinnamate derivatives isolated from roots of Scrophularia buergeriana Miquel (Scrophulariaceae) protected cultured cortical neurons from neurotoxicity induced by glutamate. Here, we have investigated the structure-activity relationships in the phenylpropanoids using our primary culture system. The ?,?-unsaturated ester moiety and the para-methoxy group in the phenylpropanoids appeared to play a vital role in neuroprotective activity. This suggested that E-p-methoxycinnamic acid (E-p-MCA) might be a crucial component for their neuroprotective activity within the phenylpropanoid compounds. E-p-MCA significantly attenuated glutamate-induced neurotoxicity when added prior to an excitotoxic glutamate challenge. The neuroprotective activity of E-p-MCA appeared to be more effective in protecting neurons against neurotoxicity induced by NMDA than from that induced by kainic acid. E-p-MCA inhibited the binding of [propyl-2,3-3H]-CGP39653 and [2-3H]-glycine to their respective binding sites on rat cortical membranes. However, even high concentrations of E-p-MCA failed to inhibit completely [propyl-2,3-3H]-CGP39653 and [2-3H]-glycine binding. Indeed, E-p-MCA diminished the calcium influx that routinely accompanies glutamate-induced neurotoxicity, and inhibited the subsequent overproduction of nitric oxide and cellular peroxide in glutamate-injured neurons. Thus, our results suggest that E-p-MCA exerts significant protective effects against neurodegeneration induced by glutamate in primary cultures of cortical neurons by an action suggestive of partial glutamatergic antagonism.

Kim, So Ra; Sung, Sang Hyun; Jang, Young Pyo; Markelonis, George J; Oh, Tae H; Kim, Young Choong

2002-01-01

318

21 CFR 184.1660 - Propyl gallate.  

Code of Federal Regulations, 2013 CFR

...locations.html. (c) The ingredient is used as an antioxidant as defined in § 170.3(o)(3) of this chapter. ...manufacturing practice results in a maximum total content of antioxidants of 0.02 percent of the fat or oil content, including...

2013-04-01

319

Alternative thermodiffusion interface for simultaneous speciation of organic and inorganic lead and mercury species by capillary GC-ICPMS using tri-n-propyl-lead chloride as an internal standard.  

PubMed

An alternative thermodiffusion interface (TDI) was designed and constructed for the effective online coupling of capillary gas chromatography (cGC) and inductively coupled plasma mass spectrometry (ICPMS). Pb(2+), (CH3)3Pb(+), (C2H5)3Pb(+), Hg(2+), CH3Hg(+) and C2H5Hg(+) were derived as Pb(C4H9)4, (CH3)3PbC4H9, (C2H5)3PbC4H9, (C4H9)2Hg, CH3HgC4H9, and C2H5HgC4H9 when butyl magnesium bromide was employed as a derivatization reagent for a proof-of-concept study, avoiding the loss of their species specific information. All these derivatives together with the neutral fully saturated (CH3)4Pb and (C2H5)4Pb could be quantitatively separated within 7 min using a 15 m long capillary column, allowing the determination and speciation of organic and inorganic Pb and Hg species in a single run. The method detection limits (3sigma) for Me4Pb, Et4Pb, Me3Pb(3+), Pb(2+), MeHg(+), EtHg(+), and Hg(2+) are 0.07, 0.06, 0.04, 7.0, 0.09, 0.1, and 0.2 pg g(-1), respectively. Moreover, tri-n-propyl-lead chloride was synthesized and used as an alternative internal standard for the accurate and simultaneous speciation analysis of Pb and Hg in complicated environmental and biological samples for the first time. This cGC-TDI-ICPMS method was validated by analyzing Pb and Hg species in certified reference materials and then was applied to simultaneous speciation analysis of Pb and Hg in real-life samples. It is expected that these approaches can be extended to the speciation of other organometallic compounds after suitable modifications and so will aid in monitoring the occurrence, pathways, toxicity, and/or biological effects of these compounds in the environment and in organisms. PMID:18576666

Yan, Dong; Yang, Limin; Wang, Qiuquan

2008-06-25

320

Catalyst-substrate adducts in asymmetric catalytic hydrogenation. Crystal and molecular structure of (((R,R)-1,2-bis(phenyl-o-anisoylphosphino)ethane)(methyl (Z)-. beta. -propyl-. alpha. -acetamidoacrylate))rhodium tetrafluoroborate, (Rh(DIPAMP)(MPAA))BF sub 4  

Microsoft Academic Search

(Rh(R,R-DIPAMP)(MeOH)){sup +} (DIPAMP = 1,2-bis(phenyl-o-anisoylphosphino)ethane), which serves as an asymmetric hydrogenation catalyst for enamides, reacts with methyl (Z)-β-propyl-α-acetamidoacrylate (MPAA) to form the 1:1 adduct, (Rh(R,R-DIPAMP)(MPAA)){sup +} (1), with a binding constant of 1.4 10⁴ M⁻¹ at 25°C. Crystals of the BF salt of the predominant diastereomer of 1 were isolated and subjected to single-crystal X-ray analysis. The structure of

B. McCulloch; J. Halpern; M. R. Thompson; C. R. Landis

1990-01-01

321

Basically Acids  

NSDL National Science Digital Library

Students learn the basics of acid/base chemistry in a fun, interactive way by studying instances of acid/base chemistry found in popular films such as Harry Potter and the Prisoner of Azkaban and National Treasure. Students learn what acids, bases and indicators are and how they can be used, including invisible ink. They also learn how engineers use acids and bases every day to better our quality of life. Students' interest is piqued by the use of popular culture in the classroom.

University Of Houston

322

Gas-Phase Reactivity of Carboxylic Acid Functional Groups with Carbodiimides  

NASA Astrophysics Data System (ADS)

Gas-phase modification of carboxylic acid functionalities is performed via ion/ion reactions with carbodiimide reagents [ N-cyclohexyl- N'-(2-morpholinoethyl)carbodiimide (CMC) and [3-(3-Ethylcarbodiimide-1-yl)propyl]trimethylaminium (ECPT)]. Gas-phase ion/ion covalent chemistry requires the formation of a long-lived complex. In this instance, the complex is stabilized by an electrostatic interaction between the fixed charge quaternary ammonium group of the carbodiimide reagent cation and the analyte dianion. Subsequent activation results in characteristic loss of an isocyanate derivative from one side of the carbodiimide functionality, a signature for this covalent chemistry. The resulting amide bond is formed on the analyte at the site of the original carboxylic acid. Reactions involving analytes that do not contain available carboxylic acid groups (e.g., they have been converted to sodium salts) or reagents that do not have the carbodiimide functionality do not undergo a covalent reaction. This chemistry is demonstrated using PAMAM generation 0.5 dendrimer, ethylenediaminetetraacetic acid (EDTA), and the model peptide DGAILDGAILD. This work demonstrates the selective gas-phase covalent modification of carboxylic acid functionalities.

Prentice, Boone M.; Gilbert, Joshua D.; Stutzman, John R.; Forrest, William P.; McLuckey, Scott A.

2013-01-01

323

Mefenamic Acid  

MedlinePLUS

... any of the following symptoms, stop taking mefenamic acid and call your doctor: stomach pain, heartburn, vomit that is bloody or looks ... Mefenamic acid may cause side effects. Tell your doctor if any of these ... nervousness ringing in the ears Some side effects can be serious. If you ...

324

Acid test  

NSDL National Science Digital Library

Baking soda can be used as an indicator of how much acid a substance contains. Lemons and limes have more acid in them than grapefruits and oranges. Indophenol can be used as an indicator of how much vitamin C is in a substance.

Olivia Worland (Purdue University;Biological Sciences)

2008-06-06

325

Acid Rain  

Microsoft Academic Search

Measurements of the acidity of rain and snow reveal that in parts of the eastern U.S. and of western Europe precipitation has changed from a nearly neutral solution 200 years ago to a dilute solution of sulfuric and nitric acids today. The trend is a result of the emission of sulfur and nitrogen oxides to the atmosphere accompanying the rise

Gene E. Likens; Richard F. Wright; James N. Galloway; Thomas J. Butler

1979-01-01

326

Acid rain  

SciTech Connect

This book was written in a concise and readable style for the lay public. It's purpose was to make the public aware of the damage caused by acid rain and to mobilize public opinion to favor the elimination of the causes of acid rain.

Elsworth, S.

1985-01-01

327

Acid rain  

SciTech Connect

This book presents the proceedings of the third annual conference sponsored by the Acid Rain Information Clearinghouse (ARIC). Topics covered include: Legal aspects of the source-receptor relationship: an energy perspective; Scientific uncertainty, agency inaction, and the courts; and Acid rain: the emerging legal framework.

White, J.C. (Cornell University, Ithaca, NY (US))

1988-01-01

328

Hydrochloric acid  

Microsoft Academic Search

The effect of a single instillation of acid and pepsin on the cell proliferation in the distal esophageal mucosa was investigated in four dogs. The doses of acid and pepsin used were lower than those provoking acute esophagitis and erosions. Usingin vitro labeling with [3H]thymidine and autoradiography, the epithelial mitotic and DNA synthesis indices were determined at 0, 4, 8,

A. De Backer; P. Haentjens; G. Willems

1985-01-01

329

Acids (GCMP)  

NSDL National Science Digital Library

Acids: this is a resource in the collection "General Chemistry Multimedia Problems". We will observe the reaction of sodium bicarbonate with three acid solutions. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

330

Domoic Acid  

NSDL National Science Digital Library

This online student report discusses the chemistry of domoic acid, a biotoxin that is produced by the diatom Psuedo-nitzschia and associated with Amnesiac Shellfish Poisoning (ASP). In addition to a descriptive summary and images, the report links to other areas of interest related to domoic acid poisoning including signs and symptoms, modes of action, and treatment.

Kohlen, Corinne; Bailey, Christina

2010-02-10

331

Acid Precipitation  

NSDL National Science Digital Library

Acid precipitation will be defined. At different points in the lesson students will write balanced reactions for the formation acid precipitation from atmospheric sulfur and nitrogen oxides and the neutralization of acids by limestone. Students will determine which states are most at risk from acid precipitation and assess how that risk has changed from 1996 to 2006. Sources of atmospheric sulfur (burning of high-sulfur coal) and nitrogen oxides (automobile exhaust) will be listed. The buffering effect of limestone soils and its mitigating effect on acid precipitation will be discussed. Students will correlate these areas with sulfur and nitrogen oxide production, population, composition of coal fields, and soil composition. This resource includes both a teaching guide and student worksheets.

Tyser, Jim

2011-09-15

332

Acid rain  

SciTech Connect

Acid precipitation has become one of the major environmental problems of this decade. It is a challenge to scientists throughout the world. Researchers from such diverse disciplines as plant pathology, soil science, bacteriology, meteorology and engineering are investigating different aspects of acid precipitation. Despite some unknowns, the preponderance of our evidence to date points to the need to control the emissions of acid-forming sulfur and nitrogen compounds. Given the potential for damage from acid precipitation, prudence dictates that we act soon to avoid far more serious problems in the future. EPA's regulatory standards for new power plants and motor vehicles are a major step in the right direction. Further steps may be required in the near future. This background document tells what we know - and don't know - about acid precipitation.

Not Available

1980-07-01

333

Acid Rain  

NSDL National Science Digital Library

Due to the presence of dissolved gases such as carbon dioxide, rainfall is naturally acidic. The release of other gases and chemicals such as sulfur dioxide during the combustion of coal and oil can cause rainfall to become even more acidic, sometimes to the point of toxicity. In this activity, students will measure the pH of local rainfall to see what effect these gases have in their region. They will also check an online resource to see how the releases of acid rain-causing chemicals have varied over the past 20 years, and answer questions about the information they uncover.

Fox, Chris

334

Tranexamic Acid  

MedlinePLUS

... or lower legs hoarseness changes in vision, including color vision chest pain shortness of breath leg pain, swelling, tenderness, redness, or warmth Tranexamic acid may cause other side effects. Call your doctor if you have any unusual ...

335

Valproic Acid  

MedlinePLUS

... with other medications to treat certain types of seizures. Valproic acid is also used to treat mania ( ... a severe, long-lasting and possibly life-threatening seizure. Your doctor will probably decrease your dose gradually.

336

Paraffin isomerization, paraffin disproportionation, and benzene alkylation catalyzed by aluminum chloride/sulfonic acid resins  

SciTech Connect

The catalytic isomerization of n-butane at 298/sup 0/-413/sup 0/K and n-pentane at 343/sup 0/-413/sup 0/K in a packed-bed flow reactor at 1 atm in the presence of aluminum chloride/sulfonic acid resin was accompanied by disproportionation and cracking. The selectivity to isomerization products was approx. 40% for n-pentane and > 99% for n-butane. Kinetics of n-butane isomerization at 308/sup 0/-338/sup 0/K were determined by using a partially deactivated catalyst batch, and the dependence of the isomerization rate on the partial pressure of n-butane was fitted using a power-law or a Langmuir-Hinshelwood rate equation. Alkylations of benzene with propylene catalyzed by sulfonic acid resin at 328/sup 0/K and aluminum chloride/sulfonic acid resin at 295/sup 0/K gave isopropylbenzene and mono- to tetra-isopropylbenzenes, respectively. A catalyst deactivation model was developed and used to correlate the time-dependent behavior of n-butane isomerization and benzene propylation. The data indicated that Broensted acid sites are responsible for the activity of the supported aluminum chloride catalyst.

Fuentes-Zurita, G.A.

1980-01-01

337

Electrospray ionization mass spectral studies of N,N-dialkylaminoethane-2-sulphonic acids.  

PubMed

Oxidative reactions of VX type compounds and N,N-dialkylaminoethane-2-thiols that are precursors for VX compounds produce N,N-dialkylaminoethane-2-sulphonic acids, N(R(1))(R(2))-CH(2)-CH(2)SO(3)H (where R(1) and R(2) = methyl, ethyl, n-propyl and isopropyl, 1-10), as the degradation products, and these degradation products are considered as markers for the detection of chemicals listed in the schedules of Chemical Weapons Convention (CWC) chemicals. Off-site detection of such degradation products in aqueous samples is an important task in the verification of CWC-related chemicals. Here we report a simple method involving the direct analysis of aqueous samples using positive and/or negative ion electrospray ionization (ESI) for the screening, detection and identification of N,N-dialkylaminoethane-2-sulphonic acids, avoiding sample preparation and chromatographic steps. The positive ion ESI mass spectra of all the compounds result in abundant [M+Na](+) ions, and the negative ion spectra show abundant [M-H](-) ions to confirm their molecular weight. The collision-induced dissociation spectra of [M+Na](+) and [M-H](-) give characteristic product ions by which it is easy to detect and identify all the studied N,N-dialkylaminoethane-2-sulphonic acids including those of isomeric compounds. The method is successfully applied to detect the spiked chemical, N,N-diisopropylaminoethane-2-sulphonic acid, present in a water sample received in a proficiency test. PMID:17979103

Lakshmi, V V S; Prabhakar, S; Murty, M R V S; Vairamani, M

2007-01-01

338

Solid phase extraction of petroleum carboxylic acids using a functionalized alumina as stationary phase.  

PubMed

Petroleum essentially consists of a mixture of organic compounds, mainly containing carbon and hydrogen, and, in minor quantities, compounds with nitrogen, sulphur, and oxygen. Some of these compounds, such as naphthenic acids, can cause corrosion in pipes and equipment used in processing plants. Considering that the methods of separation or clean up the target compounds in low concentrations and in complex matrix use large amounts of solvents or stationary phases, is necessary to study new methodologies that consume smaller amounts of solvent and stationary phases to identify the acid components present in complex matrix, such as crude oil samples. The proposed study aimed to recover acid compounds using the solid phase extraction method, employing different types of commercial stationary ion exchange phases (SAX and NH(2)) and new phase alumina functionalized with 1,4-bis(n-propyl)diazoniabicyclo[2.2.2]octane chloride silsesquioxane (Dab-Al(2)O(3)), synthesized in this work. Carboxylic acids were used as standard mixture in the solid phase extraction for further calculation of recovery yield. Then, the real sample (petroleum) was fractionated into saturates, aromatics, resins, and asphaltenes, and the resin fraction of petroleum (B1) was eluted through stationary ion exchange phases. The stationary phase synthesized in this work showed an efficiency of ion exchange comparable to that of the commercial stationary phases. PMID:22589166

de Conto, Juliana Faccin; Nascimento, Juciara dos Santos; de Souza, Driele Maiara Borges; da Costa, Luiz Pereira; Egues, Silvia Maria da Silva; Freitas, Lisiane Dos Santos; Benvenutti, Edilson Valmir

2012-04-01

339

?-Amino acids  

Microsoft Academic Search

Summary 1.It has been established that by the decarboxylation of the glycidic acid, obtained by Darzens' method from cis-decahydro-2-naphthol of m.p. 105, a mixture of stereoisomeric decahydro-2-naphthaldehydes is formed; these have not been investigated further.2.The synthesis has been affected, by Rodionov's method, of -(2-decalyl)--alanine (-aminodecahydro-2-naphthalenepropionic acid), which also appeared to be a mixture of isomers, the separation of which was

V. M. Rodionov; L. V. Antik

1953-01-01

340

Thermodynamic and quantum chemistry characterization of the adsorption of triazole derivatives during Muntz corrosion in acidic and neutral solutions  

NASA Astrophysics Data System (ADS)

Some triazole derivatives (4-amino-5-mercapto-3-methyl 1,2,4-triazole (AMMT), 4-amino-5-mercapto-3-ethyl 1,2,4-triazole (AMET) and 4-amino-5-mercapto-3-propyl 1,2,4-triazole (AMPT)) have been evaluated as new corrosion inhibitors for the corrosion of muntz alloy (60Cu 40Zn) in acidic and neutral solutions. The adsorption of these compounds has been tested thermodynamically which was found to be of a physisorption mode. Furthermore, some activation thermodynamic parameters such as ?H*, ?S* and ?G* of activation have been estimated. In addition, a trial to find a quantitative relationship between the inhibition efficiency and the electronic properties of the inhibitor molecules was carried out.

Allam, Nageh K.

2007-03-01

341

Acidizing with chemically heated weak acid  

SciTech Connect

Materials in and around a well are acidized with chemically heated, hot acid by injecting a solution of both nitrogen and heat generating reactants and a mixture of weak acid and weak acid salt that both buffers the relation and provides a weak acid acidizing solution.

Richardson, E. A.

1984-11-13

342

Stearic Acid  

ERIC Educational Resources Information Center

|A chemical laboratory information profile (CLIP) is presented for the chemical, stearic acid. The profile lists the chemical's physical and harmful characteristics, exposure limits, and symptoms of major exposure, for the benefit of teachers and students, who use the chemical in the laboratory.|

Young, Jay A.

2004-01-01

343

Acid rain  

SciTech Connect

An overview is presented of acid rain and the problems it causes to the environment worldwide. The acidification of lakes and streams is having a dramatic effect on aquatic life. Aluminum, present in virtually all forest soils, leaches out readily under acid conditions and interferes with the gills of all fish, some more seriously than others. There is evidence of major damage to forests in European countries. In the US, the most severe forest damage appears to be in New England, New York's Adirondacks, and the central Appalachians. This small region is part of a larger area of the Northeast and Canada that appears to have more acid rainfall than the rest of the country. It is downwind from major coal burning states, which produce about one quarter of US SO/sub 2/ emissions and one sixth of nitrogen oxide emissions. Uncertainties exist over the causes of forest damage and more research is needed before advocating expensive programs to reduce rain acidity. The President's current budget seeks an expansion of research funds from the current $30 million per year to $120 million.

Not Available

1984-06-01

344

In situ derivatization hollow fiber mediated liquid phase microextraction of alkylphosphonic acids from water.  

PubMed

Alkylphosphonic acids (APAs), particularly the methyl-, ethyl-, isopropyl- and n-propyl-phosphonic acids are important markers of extremely toxic nerve agents. Hence, their detection and identification is of vital importance to verification of chemical weapons convention (CWC). Verification analysis of CWC requires development of fast, reliable, simple and reproducible sample preparation methods of water and soil samples. Present investigation is focused on the optimization of alkylation of APAs in water with subsequent extraction of alkylated acids by hollow fiber liquid phase microextraction (HF-LPME). This simple and sensitive sample preparation of APAs from water offered better recoveries in comparison to conventionally used extraction technique. Under optimized conditions, the APAs were detected at the concentration of 0.5-0.75 microg/mL with S/N ratio > or = 5, whereas the LODs for alkyl APAs (monobasic APAs) were achieved up to 0.1 microg/mL. The developed method was finally tested with water samples supplied in 19th official proficiency test conducted by the OPCW. PMID:17174319

Pardasani, Deepak; Kanaujia, Pankaj K; Gupta, A K; Tak, Vijay; Shrivastava, R K; Dubey, D K

2006-12-15

345

Catalyst-substrate adducts in asymmetric catalytic hydrogenation. Crystal and molecular structure of (((R,R)-1,2-bis(phenyl-o-anisoylphosphino)ethane)(methyl (Z)-. beta. -propyl-. alpha. -acetamidoacrylate))rhodium tetrafluoroborate, (Rh(DIPAMP)(MPAA))BF sub 4  

SciTech Connect

(Rh(R,R-DIPAMP)(MeOH){sub 2}){sup +} (DIPAMP = 1,2-bis(phenyl-o-anisoylphosphino)ethane), which serves as an asymmetric hydrogenation catalyst for enamides, reacts with methyl (Z)-{beta}-propyl-{alpha}-acetamidoacrylate (MPAA) to form the 1:1 adduct, (Rh(R,R-DIPAMP)(MPAA)){sup +} (1), with a binding constant of 1.4 {times} 10{sup 4} M{sup {minus}1} at 25{degree}C. Crystals of the BF{sub 4} salt of the predominant diastereomer of 1 were isolated and subjected to single-crystal X-ray analysis. The structure of 1 resembles those deduced previously for rhodium ((1,2-bis(diphenylphosphino)ethane)(methyl(Z)-{alpha}-acetamidocinnamate))tetrafluoroborate and rhodium ((2S,3S)-2,3-bis(diphenylphosphino)butane(ethyl (Z)-{alpha}-acetamideocinnamate)) perchlorate.

McCulloch, B.; Halpern, J. (Univ. of Chicago, IL (USA)); Thompson, M.R. (Monsanto Co., St. Louis, MO (USA)); Landis, C.R. (Univ. of Colorado, Boulder (USA))

1990-05-01

346

Molecular and crystal structure of diperoxides: X-ray diffraction studies of 2,5-dimethyl-2,5-dihydroperoxyhexane, 2,5-dimethyl-2,5-dihydroperoxyhex-3-ine, 2,5-dimethyl-2,5-di( tert -butylperoxy)hexane, and 1,4-bis[2-(2- tert -butylperoxy)propyl]benzene  

Microsoft Academic Search

The crystal structures of two alkylhydrodiperoxides and two dialkyldiperoxides, namely, 2,5-dimethyl-2,5-dihydroperoxyhexane\\u000a (I), 2,5-dimethyl-2,5-dihydroperoxyhex-3-ine (II), 2,5-dimethyl-2,5-di(tert-butylperoxy) hexane (III), and 1,4-bis[2-(2-tert-butylperoxy)propyl]benzene (IV), are studied by X-ray diffraction. The structures of IIV are compared with previously studied structures of alkylhydroperoxides, dialkylhydroperoxides, and their S, Se, and Te analogues,\\u000a such as bis(alkyl)disulfides, bis(alkyl)diselenides, and bis(alkyl)ditellurides. The factors responsible for the structure\\u000a of compounds of

V. N. Khrustalev; M. Yu. Antipin; A. Yu. Kosnikov; V. L. Antonovskii

2004-01-01

347

Carbonate acidizing  

SciTech Connect

The authors present the first quantitative study and complete model of the wormholing phenomenon, leading to a means of predicting and optimizing carbonate acidizing treatments. Laboratory experiments on a gypsum model system and computer simulations show that for a given geometry, wormholes can be quantified by a unique parameter, their equivalent hydraulic length. The behavior of this quantifying parameter vs. all the system parameters is studied and allows the quantitative prediction of the efficiency of an acidizing treatment. This study highlights the fractal nature of the phenomenon, which is accounted for in the equations, and the strong effect of the sample geometry. Three types of etching can be obtained: compact, wormhole type, or homogeneous. The optimum conditions for achieving the best skin decrease correspond to the creation of wormholes and can then be defined in terms of fluid reactivity and injection rate.

Daccord, G.; Touboul, E.; Lenormand, R.

1989-02-01

348

Metal extraction by silyl-substituted diphosphonic acids. Part 2. Effect of alkyl bridge length on aggregation and metal ion extraction behavior.  

SciTech Connect

In an ongoing effort to determine the relationship between structure and function in diphosphonic acids, the aggregation and solvent extraction chemistry of four novel silicon-substituted diphosphonic acids, P,P'-di[3-(trimethylsilyl)-1-propyl] propylene- (H{sub 2}DTMSP[PrDP]), butylene- (H{sub 2}DTMSP[BuDP]), pentylene- (H{sub 2}DTMSP[PDP]), and hexylene diphosphonic acid (H2DTMSP[HDP]), were investigated. Vapor pressure osmometry indicates that H{sub 2}DTMSP[PrDP] and H{sub 2}DTMSP[PDP] are dimeric in toluene at 25 C, while H{sub 2}DTMSP[BuDP] and H{sub 2}DTMSP[HDP] are primarily trimeric and hexameric, respectively. The solvent extraction of selected alkaline earth cations (Ca, Sr, and Ba) and representative tri-, tetra-, and hexavalent actinides [Am(III), Th(IV), and U(VI)], from nitric acid solutions into o-xylene solutions of the ligands has been studied and compared to results reported previously for some analogous di(2-ethylhexyl)-substituted diphosphonic acids. Differences observed in the magnitude of distribution ratios, based on the number of bridging methylene groups, have been explained considering factors such as ligand aggregation, chelate ring size, P=O basicity (qualitatively determined by 31P nuclear magnetic resonance and infrared spectroscopy), and the relative acidities of the ligands.

McAlister, D. R.; Dietz, M. L.; Chiarizia, R.; Zalupski, P. R.; Herlinger, A. W.; Chemistry; Loyola Univ.

2002-01-01

349

Acidizing sandstone formations with fluoboric acid  

SciTech Connect

The continuing search for an effective deep-penetrating sandstone acidizing system recently has focused on fluoboric acid (HBF/sub 4/). Because this acid first must hydrolyze in water to produce HF, it was believed that deeper radial penetration of live acid could be achieved during matrix acidizing operations. However, a thorough experimental study has shown that typical formation temperatures will cause fluoboric acid to spend at a rapid rate similar to that of conventional hydrofluoric acid (HF), thereby severly limiting its usefulness in most sandstone formations. Furthermore, the same silica reprecipitation potential associated with HF acidizing is also inherent in the HBF/sub 4/ system.

Kunze, K.R.; Shaughnessy, C.M.

1983-02-01

350

Photostabilization of doxorubicin hydrochloride with radioprotective and photoprotective agents: Potential mechanism for enhancing chemotherapy during radiotherapy  

SciTech Connect

p-Aminobenzoic acid (PABA), urocanic acid, and sodium urate were found to significantly enhance the photostability of doxorubicin hydrochloride (adriamycin, (ADR)). d1-Methionine, thiourea, and glycine also increased the photostability of this drug, but to a lesser degree. Sodium thiosulfate on the other hand, was found to be detrimental to the photostability of ADR. The photostabilizing effect of PABA was found to increase with increase of its concentration and was influenced by the pH and the buffer species of the vehicle. The findings would have an impact on the enhancement of therapeutic efficacy of adriamycin when administered during radiation therapy.

Habib, M.J.; Asker, A.F.

1989-11-01

351

Synthesis, antimicrobial and anticancer activity of new thiosemicarbazone derivatives.  

PubMed

Thiosemicarbazones of p-aminobenzoic acid (PABA) were synthesized and tested for their antimicrobial and anticancer activity. Hydroxamate derivatives 4a-4l were found to have better antimicrobial and anticancer activity than their acid counterpart. Compound 4d was found to have good antimicrobial activity against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Vibrio cholerae, and Bacillus subtilis with IC(50) value of about 1 M. Compound 4f showed potent antifungal activity against Candida albicans (IC(50) ?= 1.29 M) and compound 4h showed potent anticancer activity (IC(50) ?= 0.07 M). PMID:21290424

Kulandaivelu, Umasankar; Padmini, Valisakka Gari; Suneetha, Kyatham; Shireesha, Boyapati; Vidyasagar, Jannu Vincent; Rao, Tadikonda Rama; K N, Jayaveera; Basu, Arijit; Jayaprakash, Venkatesan

2010-11-25

352

Maxima in antioxidant distributions and efficiencies with increasing hydrophobicity of gallic acid and its alkyl esters. The pseudophase model interpretation of the "cutoff effect".  

PubMed

Antioxidant (AO) efficiencies are reported to go through maxima with increasing chain length (hydrophobicity) in emulsions. The so-called "cutoff" after the maxima, indicating a decrease in efficiency, remains unexplained. This paper shows, for gallic acid (GA) and propyl, octyl, and lauryl gallates (PG, OG, and LG, respectively), that at any given volume fraction of emulsifier, the concentrations of antioxidants in the interfacial region of stripped corn oil emulsions and their efficiency order follow PG > GA > OG > LG. These results provide clear evidence that an AO's efficiency correlates with its fraction in the interfacial region. AO distributions were obtained in intact emulsions by using the pseudophase kinetic model to interpret changes in observed rate constants of the AOs with a chemical probe, and their efficiencies were measured by employing the Schaal oven test. The model provides a natural explanation for the maxima with increasing AO hydrophobicity. PMID:23701266

Losada Barreiro, Sonia; Bravo-Daz, Carlos; Paiva-Martins, Ftima; Romsted, Laurence S

2013-06-18

353

Pharmacokinetics and metabolism of N-[ N-[3-(3-hydroxy-4-methoxyphenyl) propyl]-?-aspartyl]- l-phenylalanine 1-methyl ester, monohydrate (advantame) in the rat, dog, and man  

Microsoft Academic Search

The pharmacokinetics and metabolism of advantame were evaluated in rats, dogs, and humans. The oral pharmacokinetic studies using 14C-advantame showed that advantame undergoes rapid but incomplete absorption, with an oral bioavailability of total radioactivity in the range of 423%. Data indicated that absorption was mainly as ANS9801-acid (de-esterified advantame), which was formed in the gastrointestinal tract as a result of

K. Ubukata; A. Nakayama; R. Mihara

2011-01-01

354

Understanding Acid Rain  

ERIC Educational Resources Information Center

|The term acid rain describes rain, snow, or fog that is more acidic than normal precipitation. To understand what acid rain is, it is first necessary to know what an acid is. Acids can be defined as substances that produce hydrogen ions (H+), when dissolved in water. Scientists indicate how acidic a substance is by a set of numbers called the pH

Damonte, Kathleen

2004-01-01

355

Chiral separation of FITC-labeled amino acids with gel electrochromatography using a polydimethylsiloxane microfluidic device.  

PubMed

A chiral separation model of gel electrochromatography in a polydimethylsiloxane (PDMS) microfluidic device for amino acids (AAs) is presented. Six pairs of fluorescein isothiocyanate (FITC)-labeled dansyl amino acids (Dns-AAs) were separated in a 36-mm effectual separation channel in less than 120 sec, with resolutions all above 0.96. This highly efficient PDMS chiral microfluidic chip was prepared by inserting the mixture solution of monomers, crosslinkers, and radical initiation into the microchannel via syringe. Specifically, allyl-gamma-cyclodextrin (CD) as a chiral selector and crosslinker was bonded in gamma-CD-bonded polyacrylamide (PAA) gel, which was the separation media, and was immobilized in a PDMS microchannel through the stable linkage of 3-(trimethoxysilyl)-propyl methacrylate (Bind-Silane, Sigma, St. Louis, MO, U.S.A.). The preparation not only permitted the prompt chiral separation of AAs, but also extended application of the PDMS microfluidic device by restraining its hydrophobicity through the PAA gel monolithic column. Furthermore, the longevity of the PDMS microfluidic device was prolonged significantly. This can also be a powerful way to develop a rapid and efficient bioanalysis method and portable analytical apparatus. PMID:17685238

Zeng, Hu-Lie; Li, Haifang; Wang, Xu; Lin, Jin-Ming

2007-01-01

356

Acidizing concepts - Matrix vs. fracture acidizing  

SciTech Connect

Acidizing involves a wide range of stimulation treatments that can yield impressive production increases in many wells if properly applied. Acidizing treatments are divided into two categories: matrix acidizing and fracture acidizing. To use either treatment properly, an understanding is required of what the treatments do and what is necessary to stimulate the well.

King, G.E.

1986-05-01

357

Pseudoacids. II. 2-Acylbenzoic acid derivatives.  

PubMed

Structures of derivatives of cyclic o-acylbenzoic acids, including the chloride, endo- and exocyclic amides, esters and anhydrides, are examined. 3-Chloro-1(3H)-isobenzofuranone (1), orthorhombic, Pbca, a = 11.616 (5), b = 8.120 (3), c = 15.640 (9) A; 3-methoxy-3-phenyl-1(3H)-isobenzofuranone (3), orthorhombic, P2(1)2(1)2(1), a = 6.923 (2), b = 8.291 (4), c = 21.551 (8) A; 3-hydroxy-3-phenyl-N-propyl-1(3H)-isoindolone (4), orthorhombic, P2(1)2(1)2(1), a = 8.662 (4), b = 9.551 (7), c = 17.649 (14) A; 3-(N-morpholino)-1(3H)-isobenzofuranone (5), triclinic, P1, a = 6.172 (4), b = 11.163 (7), c = 17.33 (2) A, alpha = 105.91 (6), beta = 99.85 (6), gamma = 97.57 (5) degrees; 3-(2'-benzoylbenzoyloxy)-3-phenyl-1(3H)-isobenzofuranone (7), triclinic, P1, a = 9.694 (3), b = 10.505 (4), c = 11.163 (4) A, alpha = 80.58 (3), beta = 80.41 (3), gamma = 76.49 (3) degrees; bis[1(3H)-isobenzofuranone-3-yl]ether (8), monoclinic, I2/a, a = 15.31 (2), b = 6.111 (12), c = 28.30 (5) A, beta = 101.61 (12) degrees. An open oxoacid tertiary amide is also described: N-morpholino 2'-benzoylbenzamide (6): monoclinic, P2(1)/c, a = 6.844 (4), b = 15.696 (8), c = 14.154 (7) A, beta = 99.43 (4). Pseudoacid derivatives form planar isobenzofuran and isoindole rings, and the former aldehyde/ketone carbon-heteroatom endocyclic and exocyclic bond distances show bond length variations which correlate with the relative basicities of the attached groups. Structures of both endocyclic and exocyclic nitrogen pseudoamides are reported as well as examples of the normal-pseudoanhydride and the dipseudoanhydride. PMID:9658555

Valente, E J; Martin, S B; Sullivan, L D

1998-06-01

358

New method of acidizing or acid fracturing: crosslinked acid gels  

SciTech Connect

Acid polymer gels having pH less than one have been crosslinked for retarding the chemical and physical activity of hydrochloric acid on calcareous formations. Hydrochloric acid concentrations from .0025 to 28% have been successfully crosslinked. This stimulation fluid offers high viscosity with adequate shear stability, perfect support for proppants, and clay stabilization. Additionally, the fluid provides effective fluid loss control and retardation of acid reaction enabling live acid to penetrate deeper into the formation for better formation conductivity and practically a residue-free break for rapid clean-up of the well after the job. Results of lab and field tests show the acid crosslinked system to be an effective stimulation fluid for acidizing and acid fracturing in calcareous and sandstone formations having low formation permeability.

Pabley, A.S.; Holcomb, D.L.

1980-01-01

359

Nutritional requirements of Methanomicrobium mobile.  

PubMed Central

A defined medium was developed for Methanomicrobium mobile BP. M. mobile required acetate for growth; the optimal concentration was 30 mM. Other requirements and their optimal concentrations included isobutyrate (0.65 mM), isovalerate (0.73 mM), and 2-methylbutyrate (1.5 mM). The appropriate branched-chain amino acids did not substitute for these branched-chain fatty acids. M. mobile required tryptophan at an optimal concentration of 24 microM. Indole substituted for tryptophan, but the possible precursor compounds shikimic acid and anthranilic acid and the degradation compound skatole did not. Vitamin requirements and their optimal concentrations included pyridoxine (0.49 microM), thiamine (0.15 microM), biotin (0.04 microM), and vitamin B12 (0.04 microM); p-aminobenzoic acid (0.18 microM) was required for optimal growth, but folic acid did not replace p-aminobenzoic acid. M. mobile required an unidentified growth factor found in ruminal fluid or extracts of Methanobacterium thermoautotrophicum for growth. M. mobile has a complex nutrition compared with that of other methanogens, but not an unusual nutrition in the context of organisms from the ruminal ecosystem.

Tanner, R S; Wolfe, R S

1988-01-01

360

Boronic Acid-functionalized core-shell-shell magnetic composite microspheres for the selective enrichment of glycoprotein.  

PubMed

In this work, core-shell-shell-structured boronic acid-functionalized magnetic composite microspheres Fe3O4@SiO2@poly (methyl methacrylate-co-4-vinylphenylbornoic acid) (Fe3O4@SiO2@P(MMA-co-VPBA)) with a uniform size and fine morphology were synthesized. Here, Fe3O4 magnetic particles were prepared by a solvothermal reaction, whereas the Fe3O4@SiO2 microspheres with a core-shell structure were obtained by a sol-gel process. 3-(Trimethoxysilyl) propyl methacrylate (MPS)-modified Fe3O4@SiO2 was used as the seed in the emulsion polymerization of MMA and VPBA to form the core-shell-shell-structured magnetic composite microspheres. As the boronic acid groups on the surface of Fe3O4@SiO2@P(MMA-co-VPBA) could form tight yet reversible covalent bonds with the cis-1,2-diols groups of glycoproteins, the magnetic composite microspheres were applied to enrich a standard glycoprotein, horseradish peroxidase (HRP), and the results demonstrated that the composite microspheres have a higher affinity for the glycoproteins in the presence of the nonglycoprotein bovine serum albumin (BSA) over HRP. Additionally, different monomer mole ratios of MMA/VPBA were studied, and the results implied that using MMA as the major monomer could reduce the amount of VPBA with a similar glycoprotein enrichment efficiency but a lower cost. PMID:23924282

Pan, Miaorong; Sun, Yangfei; Zheng, Jin; Yang, Wuli

2013-08-22

361

Acid rain  

SciTech Connect

Deposition of acidic substances from the atmosphere is considered by many to be, along with increasing CO/sub 2/ concentrations in the atmosphere, one of the most serious environmental problems of this generation. Despite the limited title of this small book, it touches, in a nontechnical and elementary way, on all of the important aspects of this subject: definitions, history, suspected causes and harmful effects, proposed remedial actions, the case for additional research, and political and economic impacts. The material is presented largely as statements and opinions of scientists and governmental officials. The book is reportorial in style and reasonably balanced in its presentation of contrasting and opposing opinions about causes, effects, and remedies, although the final chapter, What Citizens Can Do, includes the names and addresses of organizations involved in efforts to protect clean air, forestry and wilderness areas. Also included are school projects and examples of what individuals and groups have done to help us understand the problem and/or to promote action.

Gay, K.

1983-01-01

362

siRNA nanocarriers based on methacrylic acid copolymers.  

PubMed

Poly(ethylene glycol)-b-poly(propyl methacrylate-co-methacrylic acid) (PEG-b-P(PrMA-co-MAA) can be complexed with poly(amido amine) (PAMAM) dendrimers and nucleic acids to form pH-responsive nanosized core-shell type polyion complex micelles (PICMs). These PICMs have the ability to lose their shell and release the PAMAM/nucleic acid core under mildly acidic conditions such as those encountered in the endosomal compartment. In this work, pH-sensitive PICMs composed of PEG-b-P(PrMA-co-MAA), different PAMAMs, and siRNAs were prepared and characterized. These micelles had mean diameters ranging from 50 to 100 nm depending on the structure of the polycationic component. In order to trigger PICM uptake by receptor-mediated endocytosis, the micelles were decorated with an antibody fragment directed against the transferrin receptor (anti-CD71). The targeting ligand was stably conjugated to a semi-telechelic amino-PEG-b-P(PrMA-co-MAA) via a maleimide/activated ester bifunctional linker, yielding up to 60%-80% functionalization of the maleimide groups. The cellular uptake of the micelles was assessed on human prostate cancer cells (PC-3) via flow cytometry. Native PICMs and micelles bearing a non-specific antibody fragment were taken up to the same extent with a low efficiency, whereas anti-CD71 Fab'-decorated PICMs exhibited significantly higher uptake. The capacity of the targeted, siRNA-loaded, PICMs to downregulate the expression of the Bcl-2 anti-apoptotic oncoprotein was investigated using the appropriate unmodified or 2'-modified (2'F-RNA and 2'F-ANA) siRNA sequence. Bcl-2 mRNA and protein levels were greatly reduced when the cells were transfected with anti-CD71 decorated PICMs. Optimal silencing was achieved with the chemically modified siRNA. These data suggest that combining optimized siRNA chemistry with an effective delivery system can potentiate the activity of siRNA, thereby potentially reducing the total dose of carrier required to achieve a pharmacological effect. PMID:21195736

Felber, Arnaud E; Castagner, Bastien; Elsabahy, Mahmoud; Deleavey, Glen F; Damha, Masad J; Leroux, Jean-Christophe

2010-12-31

363

Synthesis and bio-functionalization of multifunctional magnetic Fe3O4@Y2O3:Eu nanocomposites  

PubMed Central

A facile homogenous precipitation method has been developed for the synthesis of multifunctional, magnetic, luminescent nanocomposites with Fe3O4 nanoparticles as the core and europium-doped yttrium oxide (Y2O3:Eu) as the shell. The nanocomposites showed both super-paramagnetic behavior and unique europium fluorescence properties with high emission intensity. Their surface has been modified with a bifunctional ligand, p-aminobenzoic acid (PABA), and further biofunctionalized with biotin; the nanocomposites showed specific targeting for avidin-coupled polystyrene beads.

Ma, Zhi Ya; Dosev, Dosi; Nichkova, Mikaela; Gee, Shirley J.; Hammock, Bruce D.; Kennedy, Ian M.

2010-01-01

364

Stir-bar-sorptive extraction and ultra-high-performance liquid chromatographytandem mass spectrometry for simultaneous analysis of UV filters and antimicrobial agents in water samples  

Microsoft Academic Search

Stir-bar-sorptive extraction (SBSE) with liquid desorption (LD) and ultra-high-performance liquid chromatographyelectrospray\\u000a ionization triple-quadrupole tandem mass spectrometry (UHPLC(ESI)MSMS) were used for analysis of six personal care products\\u000a in environmental water: four UV filters (2,2-dihydroxy-4-methoxybenzophenone, benzophenone-3, octocrylene, and octyldimethyl-p-aminobenzoic acid) and two antimicrobial agents (triclocarban and triclosan). Experimental conditions that affect SBSE-LD\\u000a sorption efficiency (extraction time and temperature, sample pH, and ionic

Marta Pedrouzo; Francesc Borrull; Rosa Maria Marc; Eva Pocurull

2010-01-01

365

Solid surface luminescence analysis. Progress report, April 1984-December 1984  

SciTech Connect

By using luminescence intensity and phosphorescence lifetimes, it was discovered that there are at least two mechanisms responsible for the room-temperature phosphorescence of p-aminobenzoic acid adsorbed on sodium acetate-sodium chloride mixtures. Significant progress has been made in designing accessories and modified equipment for temperature variation and humidity variation experiments. A method is almost completed for the determination of luminescence quantum efficiencies from compounds adsorbed on solid-surfaces. Cyclodextrin-sodium chloride mixtures have been shown to induce room-temperature phosphorescence from several compounds. Finally, solid-surface luminescence experiments are being used to probe various theoretical aspects of adsorption chromatography.

Hurtubise, R.J.

1985-01-01

366

Synthesis and theoretical calculations of carbazole substituted chalcone urea derivatives and studies their polyphenol oxidase enzyme activity.  

PubMed

Synthesis of carbazole substituted chalcone urea derivatives and their polyphenol oxidase enzyme activity effects on the diphenolase activity of banana tyrosinase were evaluated. Tyrosinase has been purified from banana on an affinity gel comprised of Sepharose 4B-L-tyrosine-p-aminobenzoic acid. The results showed that most of the compounds (3,4,5a,5d-h) inhibited and some of them (5c,5i-l) activated the tyrosinase enzyme activity. The molecular calculations were performed using Gaussian software for the synthesized compounds to explain the experimental results. PMID:22803668

Nixha, Arleta Rifati; Arslan, Mustafa; Atalay, Yusuf; Gener, Nahit; Ergn, Adem; Arslan, Oktay

2012-07-18

367

Preparation of Ion-Selective Membranes from Crosslinked Copolymers of Styrene and p-Vinylbenzenesulfonic Acid.  

National Technical Information Service (NTIS)

Ion-selective membranes were prepared by improved methods involving copolymerization of styrene, n-propyl-p-vinylbenzenesulfonate, and divinylbenzene (DVB) with subsequent hydrolysis of the ester. Both the highly reactive ester and DVB were purified by co...

T. G. Brydges D. G. Dawson J. W. Lorimer

1967-01-01

368

Uric acid test (image)  

MedlinePLUS

Uric acid urine test is performed to check for the amount of uric acid in urine. Urine is collected over a 24 ... testing. The most common reason for measuring uric acid levels is in the diagnosis or treatment of ...

369

Exploring the importance of piperazine N-atoms for sigma(2) receptor affinity and activity in a series of analogs of 1-cyclohexyl-4-[3-(5-methoxy-1,2,3,4-tetrahydronaphthalen-1-yl)propyl]piperazine (PB28).  

PubMed

sigma(2)-Agonist 1-cyclohexyl-4-[3-(5-methoxy-1,2,3,4-tetrahydronaphthalen-1-yl)propyl]piperazine (7, PB 28), which proved to revert doxorubicin resistance in breast cancer cells, was taken as a template to prepare new analogs. One of the two basic N-atoms was alternatively replaced by a methine or converted into an amide or ammonium function, with the aim of finding out which of them was essential for sigma(2) receptor affinity and activity. Some simply 4-substituted 1-cyclohexylpiperazines were also investigated. None of the compounds was as high-affinity as 7 (sigma(2)K(i) = 0.68, sigma(1)K(i) = 0.38 nM), proving that both basic N-atoms ensure better sigma(2) receptor binding. Amide 36 emerged as high-affinity (K(i) = 0.11 nM) and noteworthy() selective (1627-fold) sigma(1) ligand. Small N-cyclohexylpiperazine 59 displayed the highest sigma(2) affinity (K(i) = 4.70 nM). The sigma(2)/sigma(1) selectivities were generally low. Antiproliferative assay in SK-N-SH cells revealed piperidines 24 and 15 as putative sigma(2) agonists (EC(50)s 1.40 and 3.64 muM respectively) more potent than 7. PMID:19842660

Berardi, Francesco; Abate, Carmen; Ferorelli, Savina; Uricchio, Vincenzo; Colabufo, Nicola A; Niso, Mauro; Perrone, Roberto

2009-12-10

370

Bioavailability of phenolic acids  

Microsoft Academic Search

Two large classes of phenolic acids were comprised in this review: benzoic acid derivatives and cinnamic acid derivatives.\\u000a They have been found to be very extended in fruits and vegetables at different concentrations. For example, hydroxycinnamic\\u000a acids concentration was higher than that found for hydroxybenzoic acids. Concerning their consumption, hydroxycinnamic acids\\u000a provide larger contributions to the total polyphenol intake than

Sophie Lafay; Angel Gil-Izquierdo

2008-01-01

371

BBB - Domoic Acid Structure  

Center for Food Safety and Applied Nutrition (CFSAN)

... BBB - Domoic Acid Structure. Bad Bug Book: Foodborne Pathogenic Microorganisms and Natural Toxins Handbook Domoic Acid. ... More results from www.fda.gov/food/foodborneillnesscontaminants/causesofillnessbadbugbook

372

BBB - Okadaic Acid Structure  

Center for Food Safety and Applied Nutrition (CFSAN)

... BBB - Okadaic Acid Structure. Bad Bug Book: Foodborne Pathogenic Microorganisms and Natural Toxins Handbook Okadaic Acid. ... More results from www.fda.gov/food/foodborneillnesscontaminants/causesofillnessbadbugbook

373

NIACIN REQUIREMENT FOR SPORULATION OF PHYSARUM POLYCEPHALUM  

PubMed Central

Daniel, John W. (University of Wisconsin, Madison, Wis.) and Harold P. Rusch. Niacin requirement for sporulation of Physarum polycephalum. J. Bacteriol. 83:12441250. 1962.The myxomycete Physarum polycephalum undergoes sexual sporulation if exposed to light after 4 days of incubation in the dark on a salts medium containing niacin, niacinamide, or tryptophan. None of these compounds is required for growth. Quinic acid, shikimic acid, intermediates of the kynurenine pathway, diphosphopyridine nucleotide (DPN), and triphosphopyridine nucleotide (TPN) replace niacin but a number of other tryptophan metabolites do not. Analogues of niacin inhibit sporulation when added at the beginning but not at the end of dark incubation with niacin. Folic acid, p-aminobenzoic acid, and p-aminobenzenesulfonamide inhibit sporulation if added at any time during the incubation or illumination periods. Reduced di- or triphosphopyridine nucleotide, but not DPN or TPN, reverse the p-aminobenzoic acid inhibition but do not replace the light requirement or shorten the dark incubation period. Gluconate and 2-ketogluconate also replace niacin. Glucose, pyruvate, malate, and oxalacetate inhibit the niacin-induced sporulation. Iodoacetate and fluoride do not counteract the glucose effect or inhibit sporulation.

Daniel, John W.; Rusch, Harold P.

1962-01-01

374

SPION-loaded chitosan-linoleic acid nanoparticles to target hepatocytes.  

PubMed

The aim of this study was to develop a novel polymeric magnetic nanoprobe as an MRI contrast agent to target hepatocytes, as well as to evaluate the targeting ability of the nanoprobe with MRI in vivo. Superparamagnetic iron oxide nanocrystals (SPIONs) were synthesized by a thermal decomposition and seed growth method. An 1-ethyl-3-(3-(dimethylamino)-propyl) carbodiimide (EDC)-mediated reaction coupled water-soluble chitosan (WSC) to linoleic acid (LA). Twelve-nanometer-sized SPIONs were incorporated into the core of self-assembled WSC-LA nanoparticles. The morphology and size distribution of the SPION-loaded WSC-LA nanoparticles (SCLNs) were determined by transmittance electron microscopy (TEM) and dynamic light scattering (DLS), respectively. The encapsulation of SPIONs in the WSC-LA nanoparticles reduced the cytotoxicity of bare iron particles and enhanced their dispersion ability in water. The clustering of SPIONs into WSC-LA nanoparticles showed ultrasensitive magnetic behavior. After in vivo intravascular SCLN injection, MRI revealed relative signal enhancement in the liver. The localization of SCLN in hepatocytes was confirmed by Prussian blue staining and TEM analysis. We have successfully developed an ultrasensitive SCLN that effectively targets hepatocytes. The SCLN can be used as a contrast agent to aid in the diagnosis of hepatic diseases. PMID:19138733

Lee, Chang-Moon; Jeong, Hwan-Jeong; Kim, Se-Lim; Kim, Eun-Mi; Kim, Dong Wook; Lim, Seok Tae; Jang, Kyu Yoon; Jeong, Yong Yeon; Nah, Jae-Woon; Sohn, Myung-Hee

2008-12-24

375

Improved synthesis of hyaluronic acid hydrogel and its effect on tissue augmentation.  

PubMed

HA-HMDA hydrogels were developed by direct amide bond formation between the carboxyl groups of hyaluronic acid (HA) and hexamethylenediamine (HMDA) with an optimized carboxyl group modification in the preliminary experiment. However, these HA-HMDA hydrogels transformed into an unstable liquid form after steam sterilization, and were problematic for application to actual dermal filler. A new method to overcome the problem of the previously developed HA-HMDA hydrogels is to prepare them by adjusting the pH in this study. Not only are these improved HA-HMDA hydrogels prepared with lower amounts of cross-linking and activation agents compared to the previously developed hydrogels, but they also maintain a stable form after steam sterilization. These improved HA-HMDA hydrogels showed higher viscoelasticity and longer lasting effects than the previous ones, despite the fact that the amount of the HMDA used as a cross-linking agent as well as 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide (EDC) and 1-hydroxybenzotriazole monohydrated (HOBt) used as activation agents were substantially reduced. According to an invivo test using a wrinkled mouse model, the improved HA-HMDA hydrogels exhibited significantly improved tissue augmentation effects compared to a positive control of Restylane, which is widely used for the tissue augmentation throughout the world. Furthermore, histological analysis revealed excellent biocompatibility and safety of the improved synthesized HA-HMDA hydrogels. PMID:21527495

Yan, Xiang Mei; Seo, Moo Seok; Hwang, Eui Jin; Cho, Il Hwan; Hahn, Sei Kwang; Sohn, Uy Dong

2011-04-28

376

Refining Lurgi tar acids  

Microsoft Academic Search

There is disclosed a process for removing tar bases and neutral oils from the Lurgi tar acids by treating the tar acids with aqueous sodium bisulfate to change the tar bases to salts and to hydrolyze the neutral oils to hydrolysis products and distilling the tar acids to obtain refined tar acid as the distillate while the tar base salts

Greco

1984-01-01

377

Acid-Base Equilibria  

NSDL National Science Digital Library

This 9-page PDF document is part of an environmental geochemistry course taught by Dr. David Sherman at the University of Bristol. Topics include acid-base theories, aqueous systems, strong and weak acids and bases, acid-base properties of minerals, the pH of weak acid and buffered systems, and the calculation of titration curves.

Sherman, David W.; Bristol, University O.

378

21 CFR 172.860 - Fatty acids.  

Code of Federal Regulations, 2013 CFR

...acids and their associated fatty acids manufactured from fats and oils derived from edible sources: Capric acid, caprylic acid, lauric acid, myristic acid, oleic acid, palmitic acid, and stearic acid. (b) The food additive meets the...

2013-04-01

379

21 CFR 172.860 - Fatty acids.  

Code of Federal Regulations, 2010 CFR

...acids and their associated fatty acids manufactured from fats and oils derived from edible sources: Capric acid, caprylic acid, lauric acid, myristic acid, oleic acid, palmitic acid, and stearic acid. (b) The food additive meets the...

2009-04-01

380

21 CFR 172.860 - Fatty acids.  

Code of Federal Regulations, 2010 CFR

...acids and their associated fatty acids manufactured from fats and oils derived from edible sources: Capric acid, caprylic acid, lauric acid, myristic acid, oleic acid, palmitic acid, and stearic acid. (b) The food additive meets the...

2010-01-01

381

Uric acid nephrolithiasis.  

PubMed

Uric acid nephrolithiasis may be the final manifestation of various pathophysiological processes. Recent advances in renal urate transport have elucidated mechanisms by which hyperuricosuria occurs. However, in most uric acid stone formers the primary pathophysiologic defect is an excessively acidic urine pH rather than hyperuricosuria. Insulin resistance may contribute to the development of acidic urine by augmenting endogenous acid production and decreasing renal ammonium excretion. Medical management strategies focus primarily on alkali treatment or decreasing hyperuricosuria. PMID:17678984

Cameron, Mary Ann; Sakhaee, Khashayar

2007-08-01

382

Acids and Bases (Netorials)  

NSDL National Science Digital Library

Acids and Bases: this is a resource in the collection "Netorials". In this module there is an introduction to the chemical properties of acids and bases. Afterwards, the sections include topics such as Molecular Structures of Acids and Bases, Ionization constants, properties of salts, buffers and Lewis theory of Acids and Bases. The Netorials cover selected topics in first-year chemistry including: Chemical Reactions, Stoichiometry, Thermodynamics, Intermolecular Forces, Acids & Bases, Biomolecules, and Electrochemistry.

383

Detection of bound phenolic acids: prevention by ascorbic acid and ethylenediaminetetraacetic acid of degradation of phenolic acids during alkaline hydrolysis  

Microsoft Academic Search

The experimental conditions commonly used to detect bound phenolic acids by alkaline hydrolysis result in loss of several phenolic acids, particularly dihydroxy-derivatives (caffeic acid, dihydrocaffeic acid, homogentisic acid). In this study we show that the addition of ascorbic acid, a strong antioxidant, and ethylenediaminetetraacetic acid, a metal chelator, totally prevent the loss of phenolic acids during alkaline hydrolysis. In these

M Nardini; E Cirillo; F Natella; D Mencarelli; A Comisso; C Scaccini

2002-01-01

384

Gas-phase Acidities of Aspartic Acid, Glutamic Acid, and their Amino Acid Amides.  

SciTech Connect

Gas-phase acidities (GA or ?Gacid) for the two most acidic common amino acids, aspartic acid and glutamic acid, have been determined for the first time. Because of the amide linkages importance in peptides and as an aid in studying side chain versus main chain deprotonation, aspartic acid amide and glutamic acid amide were also studied. Experimental GA values were measured by proton transfer reactions in an electrospray ionization/Fourier transform ion cyclotron resonance mass spectrometer. Calculated GAs were obtained by density functional and molecular orbital theory approaches. The best agreement with experiment was found at the G3MP2 level; the MP2/CBS and B3LYP/aug-cc-pVDZ results are 34 kcal/mol more acidic than the G3MP2 results. Experiment shows that aspartic acid is more acidic than glutamic acid by ca. 3 kcal/mol whereas the G3MP2 results show a smaller acidity difference of 0.2 kcal/mol. Similarly, aspartic acid amide is experimentally observed to be ca. 2 kcal/mol more acidic than glutamic acid amide whereas the G3MP2 results show a correspondingly smaller energy difference of 0.7 kcal/mol. The computational results clearly show that the anions are all ring-like structures with strong hydrogen bonds between the OH or NH2 groups and the CO2? group from which the proton is removed. The two amino acids are main-chain deprotonated. In addition, use of the COSMO model for the prediction of the free energy differences in aqueous solution gave values in excellent agreement with the most recent experimental values for pKa. Glutamic acid is predicted to be more acidic than aspartic acid in aqueous solution due to differential solvation effects.

Li, Zhong; Matus, Myrna H.; Velazquez, Hector A.; Dixon, David A.; Cassady, Carolyn J.

2007-02-14

385

21 CFR 181.24 - Antioxidants.  

Code of Federal Regulations, 2013 CFR

...hydroxytoluene. Dilauryl thiodipropionate. Distearyl thiodipropionate. Gum guaiac. Nordihydroguairetic acid. Propyl gallate. Thiodipropionic acid. 2,4,5-Trihydroxy butyrophenone. [42 FR 14638, Mar. 15, 1977; 42 FR 56728,...

2013-04-01

386

21 CFR 181.24 - Antioxidants.  

Code of Federal Regulations, 2010 CFR

...hydroxytoluene. Dilauryl thiodipropionate. Distearyl thiodipropionate. Gum guaiac. Nordihydroguairetic acid. Propyl gallate. Thiodipropionic acid. 2,4,5-Trihydroxy butyrophenone. [42 FR 14638, Mar. 15, 1977; 42 FR 56728,...

2010-01-01

387

3,4-dihydro-2(1H)-quinolinone as a novel antidepressant drug: synthesis and pharmacology of 1-[3-[4-(3-chlorophenyl)-1-piperazinyl]propyl]-3,4- dihydro-5-methoxy-2(1H)-quinolinone and its derivatives.  

PubMed

To develop a novel antidepressant drug with central nervous system-stimulating activity, we prepared a series of 1-[omega-(4-substituted phenyl-1-piperazinyl)alkyl]-3, 4-dihydro-2(1H)-quinolinone derivatives and examined their activities by their effects at 30 and 100 mg/kg po on the sleeping time of mice anesthetized with halothane and on the time required for recovery from coma induced in mice by cerebral concussion. We examined their binding affinities for sigma receptors by evaluating their ability to inhibit [(3)H]-1,3-di(o-tolyl)guanidine ([(3)H]DTG) binding to the rat whole brain membrane in comparison with three putative sigma receptor agonists: 1,3-di(o-tolyl)guanidine (DTG, 66), (+)-1,2,3,4,5,6-hexahydro-6,11-dimethyl-3-(2-propenyl)-2, 6-methano-3-benzazecin-8-ol (SKF10,047, 67), and (+)-1,2,3,4,5, 6-hexahydro-6,11-dimethyl-3-(3-methyl-2-butenyl)-2, 6-methano-3-benzazecin-8-ol (pentazocine, 68). Among the series of derivatives, 1-[3-[4-(3-chlorophenyl)-1-piperazinyl]propyl]-3, 4-dihydro-5-methoxy-2(1H)-quinolinone hydrochloride (34b) and its mesylate (34c), at a dose of 30 mg/kg po, reduced the sleeping time and the time for recovery from coma and they inhibited [(3)H]DTG binding for sigma receptors. The putative sigma receptor agonists reduced the sleeping time and the time for recovery from coma whereas two sigma receptor antagonists, alpha-(4-fluorophenyl)-4-(5-fluoro-2-pyrimidinyl)-1-piperazinebutanol hydrochloride (BMY14802, 69) and cis-9-[3-(3, 5-dimethyl-1-piperazinyl)propyl]carbazole dihydrochloride (rimcazole, 70), were inactive in the two tests. Preadministration of the putative sigma receptor antagonists 69 (3 mg/kg po) and 70 (30 mg/kg po) completely antagonized the actions of 34b and the sigma receptor agonists in the test for recovery from coma. These results suggested that 34b and 34c are sigma receptor agonists. Furthermore, a single administration of 1 and 10 mg/kg po 34b and 34c showed antidepressant-like activity by reducing the immobility time in the forced-swimming test with mice, while a tricyclic antidepressant, 10, 11-dihydro-N,N-dimethyl-5H-dibenz[b,f]azepine-5-propanamine hydrochloride (imipramine, 1) (10 and 30 mg/kg po), did not reduce the time after a single administration. 1 reduced the time after repeated administration of 30 mg/kg po once a day for 4 days. The structure-activity relationship of the series of compounds is also discussed. PMID:10649973

Oshiro, Y; Sakurai, Y; Sato, S; Kurahashi, N; Tanaka, T; Kikuchi, T; Tottori, K; Uwahodo, Y; Miwa, T; Nishi, T

2000-01-27

388

Preparation and evaluation of molecularly imprinted microspheres for solid-phase extraction of 1,4-hydroxybenzoic acid esters in soy.  

PubMed

Molecularly imprinted microspheres (MIMs) were prepared by precipitation polymerization for the binding and recognition of 1,4-hydroxybenzoic acid esters. Ethyl p-hydroxybenzoate (EtPHB) was used as the template molecule, methacrylic acid as the functional monomer, ethylene dimethacrylate as the linking agent. It was evaluated by solid-phase extraction column packed with MIMs combined with liquid chromatography to determine trace preservatives including benzoic acid, methyl p-hydroxybenzoate, EtPHB, propyl p-hydroxybenzoate in food products. A solid-phase extraction based on MIM procedure was used to isolate four additives from the food matrix before quantitative analysis. The Scatchard plot suggested that the template-polymer system had two-site binding behavior with the dissociation constants of 0.3577 and 3.952 mg/g, respectively. The rebinding test, based on the molecularly imprinted solid-phase extraction column technique, showed the recoveries of soy samples spiked with four additives within 88.4-110.6%, with the relative standard deviations of 1.97-3.82%. Finally, the method was successfully applied for the analysis of parabens in foodstuff without traditional pretreatment. PMID:21898813

He, Juan; Shen, Yanzheng; Chen, Si; Wei, Hongliang; Zhu, Jing; You, Liqin; Lu, Kui

2011-08-24

389

Synthesis and evaluation of novel bifunctional chelating agents based on 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid for radiolabeling proteins.  

PubMed

Detailed synthesis of the bifunctional chelating agents 2-methyl-6-(p-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (1B4M-DOTA) and 2-(p-isothiocyanatobenzyl)-5, 6-cyclohexano-1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetate (CHX-DOTA) are reported. These chelating agents were compared to 2-(p-isothiocyanatobenzyl)-1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid (C-DOTA) and 1, 4, 7, 10-Tetraaza-N-(1-carboxy-3-(4-nitrophenyl)propyl)-N', N", N"'-tris(acetic acid) cyclododecane (PA-DOTA) as their (177)Lu radiolabeled conjugates with Herceptin. In vitro stability of the immunoconjugates radiolabeled with (177)Lu was assessed by serum stability studies. The in vivo stability of the radiolabeled immunoconjugates and their targeting characteristics were determined by biodistribution studies in LS-174T xenograft tumor-bearing mice. Relative radiolabeling rates and efficiencies were determined for all four immunoconjugates. Insertion of the 1B4M moiety into the DOTA backbone increases radiometal chelation rate and provides complex stability comparable to C-DOTA and PA-DOTA while the CHX-DOTA appears to not form as stable a (177)Lu complex while exhibiting a substantial increase in formation rate. The 1B4M-DOTAmay have potential for radioimmunotherapy applications. PMID:12900284

Chappell, L L; Ma, D; Milenic, D E; Garmestani, K; Venditto, V; Beitzel, M P; Brechbiel, M W

2003-08-01

390

Acid Functionalized Mesoporous Ordered Materials for the Production of 5-Hydroxymethyfurfural from Carbohydrates  

NASA Astrophysics Data System (ADS)

Solid acid catalysts were designed for the conversion of fructose to 5-hydroxymethylfurfural (HMF). Some of the catalysts incorporate thioether groups to promote the tautomerization of fructose to its furanose form, as well as sulfonic acid groups to catalyze its dehydration. A bifunctional silane, 3-((3-(trimethoxysilyl)propyl)thio)propane-1-sulfonic acid (TESAS), was designed for incorporation into SBA-15-type silica by co-condensation. To achieve mesopore ordering in the functionalized silica, the standard SBA-15 synthetic protocol was modified, resulting in well-formed hexagonal particles. Functional groups incorporated into mesoporous silica by co-condensation are more robust under the reaction conditions than those grafted onto a non-porous silica. In a variation, the thioether group of TESAS was oxidized by H2O 2 to the sulfone during the synthesis of the modified SBA-15. The materials were tested in batch reactors and compared in the selective dehydration of fructose to 5-hydroxymethylfurfural (HMF). Compared to benchmark catalysts, the thioether-containing TESAS-SBA-15 showed the highest activity in the dehydration of aqueous fructose, as well as the highest selectivity towards HMF (71 % at 84 % conversion). In addition, the stability of several supported acid catalysts was evaluated in tubular reactors designed to produce 5-hydroxymethylfurfural (HMF) continuously. The reactors, packed with the solid catalysts, were operated at 403 K for extended periods, up to 180 h. The behaviors of three propylsulfonic acid-functionalized, ordered porous silicas (one inorganic SBA-15-type silica, and two ethane-bridged SBA-15-type organosilicas) were compared with that of a propylsulfonic acid-modified, non-ordered porous silica. The HMF selectivity of the catalysts with ordered pore structures ranged from 60 to 75 %, while the selectivity of the non-ordered catalyst peaked at 20 %. The latter was also the least stable, deactivating with a first-order rate constant of 0.152 h-1. The organosilicas are more hydrothermally stable and maintained a steady catalytic activity longer than inorganic SBA-15-type silica. The organosilica with an intermediate framework ethane content of 45 mol % was the most stable, with a first-order deactivation rate constant of only 0.012 h-1. Deactivation under flow conditions is caused primarily by hydrolytic cleavage of acid sites, which can be (to some extent) recaptured by the free surface hydroxyl groups of the silica surface.

Crisci, Anthony J.

391

Acid Inhibition and the Acid Rebound Effect  

Microsoft Academic Search

Acid secretion from gastric parietal cells is a result of a complex interaction between different stimulatory and inhibitory mediators. One of the most important mediators is gastrin, which stimulates gastric acid secretion from parietal cells mostly indirectly, by the release of histamine from enterochromaffin-like (ECL) cells. Therapy with antisecretory agents leads to hypergastrinemia, mucosal hyperplasia and increased ECL cell mass,

Marko Duvnjak

2011-01-01

392

Acid Thunder: Acid Rain and Ancient Mesoamerica  

ERIC Educational Resources Information Center

|Much of Mesoamerica's rich cultural heritage is slowly eroding because of acid rain. Just as water dissolves an Alka-Seltzer tablet, acid rain erodes the limestone surfaces of Mexican archaeological sites at a rate of about one-half millimeter per century (Bravo et al. 2003). A half-millimeter may not seem like much, but at this pace, a few

Kahl, Jonathan D. W.; Berg, Craig A.

2006-01-01

393

Purification of oleic acid and linoleic acid  

SciTech Connect

To permit kinetic studies of the reactivity of unsaturated fatty acids towards oxygen radicals, it is essential to remove traces of hydroperoxides and other conjugated lipid impurities commonly present in commercial samples. Removal of these impurities has been satisfactorily achieved for oleic and linoleic acids by anaerobic low temperature recrystallization from acetonitrile. The uv spectra of commercial and purified samples are compared.

Arudi, R.L.; Sutherland, M.W.; Bielski, B.H.J.

1983-01-01

394

New bioactive fatty acids.  

PubMed

Many oxygenated fatty acids are bioactive compounds. Nocardia cholesterolicum and Flavobacterium DS5 convert oleic acid to 10 hydroxy stearic acid and linoleic acid to 10-hydroxy-12(Z)-octadecanoic acid. Pseudomonas aeruginosa PR3 converts oleic acid to the new compounds, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD) through 10-hydroxy-8-octadecenoic acid, and racinoleic acid to 7,10,12-trihydroxy-8-octadecenoic acid. DOD showed antibacterial activity including against food-borne pathogens. Bacillus megaterium ALA2 converted n-6 and n-3 PUFAs to many new oxygenated fatty acids. For example: linoleic acid was converted to12,13-epoxy-9-octadecenoic acid and then to 12,13-dihydroxy-9-octadecenoic acid (12,13-DHOA). From here, there are two bioconversion pathways. The major pathway is: 12,13-DHOA --> 12,13,17-trihydroxy-9(S)-octadecenoic acid (THOA) --> 12,17;13,17-diepoxy-16-hydroxy-9(Z)-octadecenoic acid (DEOA) --> 7-hydroxy-DEOA. The minor pathway is: 12,13-DHOA --> 12,13,16-THOA --> 12-hydroxy-13,16-epoxy-9(Z)-octadecenoic acid. 12,13,17-THOA has anti-plant pathogenic fungal activity. The tetrahydrofuranyl moiety is known in anti cancer drugs. Strain ALA2 also converts other n-3 and n-6 PUFAs such as eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (AA) to many new oxygenated unsaturated fatty acid products. All of these new products have high potential for antimicrobial agents or biomedical applications. We also screened 12 Mortierella fungal strains from the ARS Culture Collection for the production of bioactive fatty acids such as dihomo-gama-linolenic acid (DGLA) and arachidonic acid. All of the strains tested produced AA and DGLA from glucose or glycerol. The top five AA producers (mg AA/g CDW) were in the following order: M. alpina > M. zychae > M. hygrophila > M. minutissima > M. parvispora. Both AA and DGLA are important natural precursors of a large family of prostaglandin and thromboxane groups. PMID:18296335

Hou, Ching T

2008-01-01

395

Zoledronic Acid Injection  

MedlinePLUS

... acid (Reclast) is used to prevent or treat osteoporosis (condition in which the bones become thin and ... Zoledronic acid (Reclast) is also used to treat osteoporosis in men, and to prevent or treat osteoporosis ...

396

Mixed Acid Oxidation  

SciTech Connect

Several non-thermal processes have been developed to destroy organic waste compounds using chemicals with high oxidation potentials. These efforts have focused on developing technologies that work at low temperatures, relative to incineration, to overcome many of the regulatory issues associated with obtaining permits for waste incinerators. One such technique with great flexibility is mixed acid oxidation. Mixed acid oxidation, developed at the Savannah River Site, uses a mixture of an oxidant (nitric acid) and a carrier acid (phosphoric acid). The carrier acid acts as a non-volatile holding medium for the somewhat volatile oxidant. The combination of acids allows appreciable amounts of the concentrated oxidant to remain in the carrier acid well above the oxidant''s normal boiling point.

Pierce, R.A.

1999-10-26

397

Hydrochloric acid poisoning  

MedlinePLUS

Hydrocholoric acid is a clear, poisonous liquid. It is highly corrosive, which means it immediately causes severe damage, such ... poisoning due to swallowing or breathing in hydrochloric acid. This is for information only and not for ...

398

Acid-fast stain  

MedlinePLUS

The acid-fast stain is a laboratory test that determines if a sample of tissue, blood, or other body ... lab team member washes the slide with an acid solution and applies a different stain. The bacteria ...

399

Carbolic acid poisoning  

MedlinePLUS

Phenol poisoning; Phenylic acid poisoning; Hydroxybenzene poisoning; Phenic acid poisoning; Benzenol poisoning ... Phenol ... and Disease Registry (ATSDR). 2008. Toxicological profile for Phenol. Atlanta, GA: U.S. Department of Health and Human ...

400

Lactic acid test  

MedlinePLUS

Lactate test ... test. Exercise can cause a temporary increase in lactic acid levels. ... oxygen. See: Oxygen deprivation Conditions that can increase lactic acid levels include: Heart failure Liver problems Lung disease ...

401

Aminocaproic Acid Injection  

MedlinePLUS

Aminocaproic acid injection is used to control bleeding that occurs when blood clots are broken down too quickly. This ... the baby is ready to be born). Aminocaproic acid injection is also used to control bleeding in ...

402

Polymerization of Itaconic Acid.  

National Technical Information Service (NTIS)

Itaconic acid has various uses in chain copolymerization reactions, because of its two carboxylic groups and relatively good reactivity with different comonomers. As an unsaturated dicarboxylic acid it also has applications in grafting reactions and polyc...

J. Ahlgren

1990-01-01

403

Behavioral effects of alpha-alkylated amino acid analogs in the C57BL/6J mouse.  

PubMed

Although a series of amino acid analogs have been shown to modulate brain function, information on the pharmacology of alpha-alkylated amino acids (AAAA) is limited. In particular there is no information on the effect of these amino acid analogs (AAA) on the elevated plus maze, the tail suspension test and the forced swim test. It was therefore the aim of the study to test a series of AAAA in these paradigms in order to explore behavioral activities of this compound class. 10 male mice per group aged between 10 and 14 weeks were used. Vehicle-treated controls were used in addition to intraperitoneal injections of 1, 10 and 100mg/kg body weight of each, alpha-amino-isobutyic acid (AIB), isovaline (IVA), alpha-propyl-alanine (APA), alpha-butyl-alanine (ABA), alpha-pentyl-alanine (APnA), alpha-ethylphenylglycine (AEPG) and alpha-methyl-valine (AMV). The elevated plus maze (EPM), the tail suspension test (TST) and forced swim test (FST) were used for behavioral testing. There were dose-dependent results: all compounds increased time and pathlength in the open arm of the EPM at least at one dose administered. In the TST and in the FST only the 100mg dose was showing an effect. The results show pharmacological activity modifying the EPM in low doses suggesting the use in treatment of behavioral traits and symptoms represented by or linked to the EPM including anxiety-related behavior including depression. Compounds acting at higher doses may be used to induce behavioral changes and thus serve as neurobiological-neuropharmacological tools. PMID:23756141

Sase, Ajinkya; Brckner, Hans; Hger, Harald; Pollak, Arnold; Lubec, Gert

2013-06-10

404

Acid inhibition and the acid rebound effect.  

PubMed

Acid secretion from gastric parietal cells is a result of a complex interaction between different stimulatory and inhibitory mediators. One of the most important mediators is gastrin, which stimulates gastric acid secretion from parietal cells mostly indirectly, by the release of histamine from enterochromaffin-like (ECL) cells. Therapy with antisecretory agents leads to hypergastrinemia, mucosal hyperplasia and increased ECL cell mass, which results in increase of gastric acid secretion capacity. This increased secretion capacity has been shown to manifest itself after antisecretory therapy withdrawal as rebound acid hypersecretion (RAH). Various studies have quantified acid hypersecretion after the cessation of therapy with H(2) antagonists and proton-pump inhibitors (PPIs). While most of those studies had small patient numbers, the findings generally demonstrate that RAH after H(2) antagonist therapy is of low magnitude, short duration, and has questionable clinical significance. On the contrary, acid hypersecretion after PPI therapy is more pronounced, lasts longer, and could possibly be the cause of acid-related symptoms. Potential for causing symptoms has recently been confirmed in two randomized placebo-controlled studies, and while we witness the increasing use of PPIs, RAH could become a proven cause of failure to withdraw therapy in a proportion of patients with reflux or dyspeptic symptoms. PMID:22095014

Leroti?, Ivan; Bari?, Neven; Stojsavljevi?, Sanja; Duvnjak, Marko

2011-11-16

405

Nucleic acid molecule  

US Patent & Trademark Office Database

The invention relates to an isolated nucleic acid molecule encoding a polypeptide capable of producing a triterpenoid hydrocarbon. The invention also relates to the encoded polypeptide, a vector comprising the nucleic acid molecule, a recombinant non-human organism comprising the nucleic acid molecule, and to methods of producing a triterpenoid hydrocarbon or an intermediate of biofuel using the nucleic acid molecule, polypeptide or recombinant organism.

Ball; Andrew (Bedford Park, AU); Moore; Robert (Bedford Park, AU); Knowles; Gregory (Bedford Park, AU); Qin; Jian (Bedford Park, AU)

2011-10-11

406

Plant fatty acid hydroxylases  

DOEpatents

This invention relates to plant fatty acyl hydroxylases. Methods to use conserved amino acid or nucleotide sequences to obtain plant fatty acyl hydroxylases are described. Also described is the use of cDNA clones encoding a plant hydroxylase to produce a family of hydroxylated fatty acids in transgenic plants. In addition, the use of genes encoding fatty acid hydroxylases or desaturases to alter the level of lipid fatty acid unsaturation in transgenic plants is described.

Somerville, Chris (Portola Valley, CA); Broun, Pierre (Burlingame, CA); van de Loo, Frank (Lexington, KY)

2001-01-01

407

Quinolinic acid, ?-picolinic acid, fusaric acid, and 2,6-pyridinedicarboxylic acid enhance the Fenton reaction in phosphate buffer  

Microsoft Academic Search

Quinolinic acid, ?-picolinic acid, fusaric acid, and 2,6-pyridinedicarboxylic acid enhanced the Fenton reaction in phosphate buffer, respectively. The enhancement by quinolinic acid, ?-picolinic acid, fusaric acid, and 2,6-pyridinedicarboxylic acid of the Fenton reaction may be partly related to their respective actions in the biological systems such as a neurotoxic effect (quinolinic acid), a marked growth-inhibitory action on rice seeding (?-picolinic

Hideo Iwahashi; Hiroyuki Kawamori; Kazuaki Fukushima

1999-01-01

408

The Acid Rain Reader.  

ERIC Educational Resources Information Center

|A topic which is often not sufficiently dealt with in elementary school textbooks is acid rain. This student text is designed to supplement classroom materials on the topic. Discussed are: (1) "Rain"; (2) "Water Cycle"; (3) "Fossil Fuels"; (4) "Air Pollution"; (5) "Superstacks"; (6) "Acid/Neutral/Bases"; (7) "pH Scale"; (8) "Acid Rain"; (9)

Stubbs, Harriett S.; And Others

409

What Is Acid Rain?  

ERIC Educational Resources Information Center

|Acid rain is the collective term for any type of acidified precipitation: rain, snow, sleet, and hail, as well as the presence of acidifying gases, particles, cloud water, and fog in the atmosphere. The increased acidity, primarily from sulfuric and nitric acids, is generated as a by-product of the combustion of fossil fuels such as coal and oil.

Likens, Gene E.

2004-01-01

410

Bile acid diarrhea.  

PubMed

Bile acids normally undergo enterohepatic circulation. When this circulation is interrupted, bile acids enter the colon in increased concentrations. Here, they produce Cl- secretion by a calcium- and cyclic AMP-dependent mechanism, resulting in diarrhea. Cholestasis may lead to serum bile acid concentrations high enough to produce colonic secretion by serosal surface effects. When resection or disease interferes with ileal function, the resulting diarrhea can be clearly attributed to bile acid malabsorption. In other states, such as postcholecystectomy diarrhea and idiopathic bile acid diarrhea, the role of bile acids is less well defined. 23-75Selena-25-homotaurocholic acid provides a way of tracing the metabolism of bile acids and their enterohepatic circulation in vivo. Metabolized similarly to natural bile acids, its circulation is easily traced by scintigraphy. Barium x-rays, serum concentrations of bile acids or bile acid intermediates, and tests of vitamin B12 absorption provide indirect measures of ileal function. Careful history and examination combined with one of many the available tests of ileal function allow a diagnosis. A therapeutic trial with a bile acid binding resin confirms the impression and treats the diarrhea. PMID:9571377

Potter, G D

411

Acid (and Base) Rainbows  

NSDL National Science Digital Library

Learners use red cabbage juice and pH indicator paper to test the acidity and basicity of household materials. The activity links this concept of acids and bases to acid rain and other pollutants. Resource contains vocabulary definitions and suggestions for assessment, extensions, and scaling for different levels of learners.

Kolenbrander, Amy; Yowell, Janet; Mach, Natalie; Zarske, Malinda S.; Carlson, Denise; Perez, Sharon

2004-01-01

412

[alpha]-Oxocarboxylic Acids  

ERIC Educational Resources Information Center

|Several [alpha]-oxocarboxylic acids play key roles in metabolism in plants and animals. However, there are inconsistencies between the structures as commonly portrayed and the reported acid ionization constants, which result because the acids are predominantly hydrated in aqueous solution; that is, the predominant form is RC(OH)[subscript 2]COOH

Kerber, Robert C.; Fernando, Marian S.

2010-01-01

413

The potential application of a poly(3,4-ethylenedioxythiopene) modified platinum DNA biosensor in mutation analysis.  

PubMed

In this study, we have fabricated a label free DNA biosensor by modifying the platinum wire with electrochemically synthesized poly(3,4-ethylenedioxythiopene) and poly(p-aminobenzoic acid). A designed single-strand DNA oligo was immobilized with the carboxyl group of poly(p-aminobenzoic acid) and served as the probe, a target DNA was then hybridized with the probe under a proper condition. Differential pulse voltammetry was performed to characterize the hybridization efficiency in the presence of daunorubicin hydrochloride that was able to be intercalated into the hybridized double-strand DNA and possessed the redox activity. Our results revealed a satisfied linear correlation between the peak current of differential pulse voltammetry and the concentration of complementary target DNA. On the other hand, the mismatches between the target- and probe-DNA caused a significant reduction of electrochemical response, in which was correlated with the amount of mismatched base pairs, therefore the current DNA biosensor had potential applications not only in DNA quantification but also in mutation detection for clinical diagnostics and laboratory applications. PMID:22040746

Gu, Yesong; Lai, Meng-Tsun

2011-10-18

414

The ecotoxicity and the biodegradability of lactic acid, alkyl lactate esters and lactate salts.  

PubMed

The ecotoxicity of lactic acid, its alkyl esters and selected metal salts was studied experimentally with the micro alga Selenastrum capricornutum, the crustacean Daphnia magna and the fish species Brachydanio rerio and Pimephales promelas. In addition, the biodegradation of lactate esters was also studied. The aim of the study was to provide predicted environmental data for additional alkyl homologues and metal salts. The ecotoxicity data are evaluated by means of Structure Activity Relations (SAR), using literature data on a non-polar narcotic mechanism of toxicity as a baseline for comparison. Lactate salts were evaluated by comparison to the toxicity of the metal ion. For the fish and D. magna, it was evident that methyl, ethyl, propyl and to a lesser extent butyl lactate were slightly more toxic in comparison to baseline non-polar narcotic toxicity data. The toxicity tests carried out with lactate-salts demonstrated clearly that the toxicity in standard tests is only determined by the associated cation and not by the lactate part. Lactic acid and its alkyl esters were degraded for more than 60% in the ready biodegradability tests and from the data presented, it is evident that the majority of alkyl lactates are readily biodegradable. The results presented in this study indicate that alkyl lactate esters show some differences in their ecotoxicity when compared to non polar narcotic compounds in but that these differences are generally small. When aquatic toxicity is considered together with their rapid tendency to biodegrade, it is concluded that lactate esters show generally favourable environmental characteristics. PMID:9734323

Bowmer, C T; Hooftman, R N; Hanstveit, A O; Venderbosch, P W; van der Hoeven, N

1998-09-01

415

Uric acid nephrolithiasis.  

PubMed

Uric acid is the end-product of purine nucleotide metabolism in man. The renal handling of urate is a complicated process, resulting in a fractional clearance of 8.2-10.3%. The anhydrous form is thermodynamically the most stable uric acid crystal. Uric acid is a weak acid that ionizes with a Pka at pH 5.75. At the normal acidic region, uric acid solubility is strongly increased by urinary pH. The prevalence of uric acid stones varies between countries, reflecting climatic, dietary, and ethnical differences, ranging from 2.1% (in Texas) to 37.7% (in Iran). The risk for uric acid stone formation correlates with the degree of uric acid supersaturation in the urine, depending on uric acid concentration and urinary pH. Hyperuricosuria is the major risk factor, the most common cause being increased purine intake in the diet. Acquired and hereditary diseases accompanied by hyperuricosuria and stone disease include: gout, in strong correlation with the amount of uric acid excreted, myelo- and lymphoproliferative disorders, multiple myeloma, secondary polycythemia, pernicious anemia and hemolytic disorders, hemoglobinopathies and thalassemia, the complete or partial deficiency of HGPRT, superactivity of PRPP synthetase, and hereditary renal hypouricemia. A common denominator in patients with idiopathic and gouty stone formers is a low urinary pH. Uric acid nephrolithiasis is indicated in the presence of a radiolucent stone, a persistent undue urine acidity and uric acid crystals in fresh urine samples. A radiolucent stone in combination with normal or acidic pH should raise the possibility of urate stones.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7783706

Halabe, A; Sperling, O

1994-01-01

416

Acid Strengths of Some Substituted Picric Acids.  

National Technical Information Service (NTIS)

The aqueous dissociation constants for a number of substituted picric acids and related compounds were determined spectrophotometrically, and the values obtained correlated with the mid-equivalence potentials obtained by half-neutralization in acetone sol...

P. J. Pearce R. J. J. Simkins

1968-01-01

417

Editorial: Acid precipitation  

SciTech Connect

This editorial focuses on acid rain and the history of public and governmental response to acid rain. Comments on a book by Gwineth Howell `Acid Rain and Acid Waters` are included. The editor feels that Howells has provide a service to the environmental scientific community, with a textbook useful to a range of people, as well as a call for decision makers to learn from the acid rain issue and use it as a model for more sweeping global environmental issues. A balance is needed among several parameters such as level of evidence, probability that the evidence will lead to a specific direction and the cost to the global community. 1 tab.

NONE

1995-09-01

418

Equilibrium fracture acidizing  

SciTech Connect

This patent describes a method for acidizing a formation penetrated by a well comprising: injecting acid into the formation at a pressure sufficient to initiate and propagate a fracture in the formation; reducing the injection rate of the acid into the fracture to a rate sufficient to hold the fracture open without significant further extension, such that the acid contacts and etches the fracture; and reducing the injection rate of the acid into the fracture to a rate that is sufficient to hold the fracture open.

Tinker, S.J.

1989-06-06

419

[Uric acid nephrolithiasis].  

PubMed

Uric acid nephrolithiasis is frequent accounting for 10% of urinary stones in industrialized countries. Its frequency will increase in the next decades because of the ageing and the increasing prevalence of obesity and type 2 diabetes mellitus. The pathophysiologic defect is an excessively acidic urine pH rather than hyperuricosuria. Undissociated uric acid is poorly soluble in acidic urines (pH < 5.5) but solubility increases when sodium urate forms at higher pH. Insulin resistance may contribute to the development of acidic urine because of higher net acid excretion. Because uric acid kidney stones are radiolucent, diagnosis is based on echography and tomodensitometry. Medical management strategies focus primarily on alkali treatment and/or decreasing hyper-uricosuria. PMID:21563421

Dussol, Bertrand

2011-03-01

420

Palladium(II) complexes with R(2)edda derived ligands. Part IV. O,O'-dialkyl esters of (S,S)-ethylenediamine-N,N'-di-2-(4-methyl)-pentanoic acid dihydrochloride and their palladium(II) complexes: synthesis, characterization and in vitro antitumoral activity against chronic lymphocytic leukemia (CLL) cells.  

PubMed

Four novel bidentate N,N'-ligand precursors, including O,O'-dialkyl esters (alkyl = ethyl, n-propyl, n-butyl and n-pentyl), L1 x 2 HCl-L4 x 2 HCl, of (S,S)-ethylenediamine-N,N'-di-2-(4-methyl)-pentanoic acid dihydrochloride [(S,S)-H(4)eddl]Cl(2) and the corresponding palladium(II) complexes 1-4, were prepared and characterized by IR, (1)H NMR and (13)C NMR spectroscopy and elemental analysis. In vitro cytotoxicity of all compounds was determined against chronic lymphocytic leukemia cells (CLL). The compounds were found to exhibit higher antitumoral activity than cisplatin. The most active compound 2, [PdCl(2){(S,S)-nPr(2)eddl}], was found to be 13.6 times more active than cisplatin on CLL cells. PMID:20570025

Vuji?, Jelena M; Cvijovi?, Milica; Kaluderovi?, Goran N; Milovanovi?, Marija; Zmejkovski, Bojana B; Volarevi?, Vladislav; Arsenijevi?, Nebojsa; Sabo, Tibor J; Trifunovi?, Sre?ko R

2010-05-12

421

Process for the preparation of lactic acid and glyceric acid  

DOEpatents

Hexose and pentose monosaccharides are degraded to lactic acid and glyceric acid in an aqueous solution in the presence of an excess of a strongly anionic exchange resin, such as AMBERLITE IRN78 and AMBERLITE IRA400. The glyceric acid and lactic acid can be separated from the aqueous solution. Lactic acid and glyceric acid are staple articles of commerce.

Jackson, James E [Haslett, MI; Miller, Dennis J [Okemos, MI; Marincean, Simona [Dewitt, MI

2008-12-02

422

The Enzymic Conversion of the Tartaric Acids to Oxaloacetic Acid  

Microsoft Academic Search

SUMMARY: Certain bacteria of the genus Pseudomonas attack the tartaric acids by means of inducible stereospecific dehydrases. Each dehydrase converts its specific isomeric substrate to oxaloacetic acid ; in crude cell-free extracts the oxaloacetic acid is in turn converted to pyruvic acid, which accumulates. By treatment of the crude extracts with ethylenediaminetetraacetic acid (EDTA), substantial accumulations of oxaloacetic acid can

M. SHILO

1957-01-01

423

Isoprenoid Acids in Recent Sediments.  

National Technical Information Service (NTIS)

Phytanic acid, pristanic acid, and 4,8,12-trimethyltridecanoic acid have been isolated from three recent marine sediments. The ratio of palmitic to pristanic acid is similar to that encountered in typical marine lipids. This suggests a biochemical origin ...

M. Blumer W. J. Cooper

1968-01-01

424

Synthesis and Evaluation of Amino Acid-Based Radiotracer 99mTc-N4-AMT for Breast Cancer Imaging  

PubMed Central

Purpose. This study was to develop an efficient synthesis of 99mTc-O-[3-(1,4,8,11-tetraazabicyclohexadecane)-propyl]-?-methyl tyrosine (99mTc-N4-AMT) and evaluate its potential in cancer imaging. Methods. N4-AMT was synthesized by reacting N4-oxalate and 3-bromopropyl AMT (N-BOC, ethyl ester). In vitro cellular uptake kinetics of 99mTc-N4-AMT was assessed in rat mammary tumor cells. Tissue distribution of the radiotracer was determined in normal rats at 0.54?h, while planar imaging was performed in mammary tumor-bearing rats at 30120 min. Results. The total synthesis yield of N4-AMT was 14%. Cellular uptake of 99mTc-N4-AMT was significantly higher than that of 99mTc-N4. Planar imaging revealed that 99mTc-N4-AMT rendered greater tumor/muscle ratios than 99mTc-N4. Conclusions. N4-AMT could be synthesized with a considerably high yield. Our in vitro and in vivo data suggest that 99mTc-N4-AMT, a novel amino acid-based radiotracer, efficiently enters breast cancer cells, effectively distinguishes mammary tumors from normal tissues, and thus holds the promise for breast cancer imaging.

Kong, Fan-Lin; Ali, Mohammad S.; Zhang, Yinhan; Oh, Chang-Sok; Yu, Dong-Fang; Chanda, Mithu; Yang, David J.

2011-01-01

425

NAHA, a Novel Hydroxamic Acid-Derivative, Inhibits Growth and Angiogenesis of Breast Cancer In Vitro and In Vivo  

PubMed Central

Background We have recently synthesized novel N-alkylated amino acid-derived hydroxamate, 2-[Benzyl-(2-nitro-benzenesulfonyl)-amino]-N-hydroxy-3-methyl-N-propyl-butyramide (NAHA). Here, we evaluate the anticancer activity of NAHA against highly invasive human breast cancer cells MDA-MB-231 in vitro and in vivo. Methodology/Principal Findings Cell growth was evaluated by MTT and soft agar assays. Protein expression was determined by DNA microarray and Western blot analysis. Metastatic potential was evaluated by cell adhesion, migration, invasion, capillary morphogenesis, and ELISA assays. The anticancer activity in vivo was evaluated in mouse xenograft model. NAHA inhibited proliferation and colony formation of MDA-MB-231 cells together with the down-regulation of expression of Cdk2 and CDC20 proteins. NAHA inhibited cell adhesion, migration, and invasion through the suppression of secretion of uPA. NAHA suppressed secretion of VEGF from MDA-MB-231 cells and inhibited capillary morphogenesis of human aortic endothelial cells (HAECs). Finally, NAHA at 50 mg/kg was not toxic and decreased tumor volume and tumor weight in vivo. This suppression of tumor growth was associated with the inhibition of mitotic figures and induction of apoptosis, and the reduction of CD31 and VEGF positive cells in tumors. Conclusion NAHA could be a novel promising compound for the development of new drugs for the therapy of invasive breast cancers.

Jiang, Jiahua; Thyagarajan-Sahu, Anita; Krchnak, Viktor; Jedinak, Andrej; Sandusky, George E.; Sliva, Daniel

2012-01-01

426

Fatty acids and neurodevelopment.  

PubMed

Knowledge of the importance of docosahexaenoic acid (DHA), arachidonic acid (AA), and long-chain polyunsaturated fatty acids (LCPUFAs) in neurodevelopment was originally obtained from animal studies. These fatty acids are rapidly accreted in brain during the first postnatal year in animal and human infants, and they are found in high concentrations in breast milk. Reports of enhanced intellectual development in breast-fed children, and reports linking LCPUFA deficiency with neurodevelopmental disorders have stressed the physiological importance of DHA in visual and neural systems. In addition to high concentrations of fatty acids in breast milk, they are also present in fish and algae oil and have recently been added to infant formulas. Esterified poplyunsaturated fatty acids act in cellular membranes, in signal transduction, in neurotransmission, and in the formation of lipid rafts. Nonesterified polyunsaturated fatty acids can modulate gene expression and ion channel activities, thus becoming neuroprotective agents. The conversion of linoleic acid and alpha-linolenic acid into ARA and DHA have led to randomized clinical trials that have studied whether infant formulas supplemented with DHA or both DHA and ARA would enhance visual and cognitive development. This review gives an overview of fatty acids and neurodevelopment, focusing on the findings from these studies. PMID:18667917

Belkind-Gerson, J; Carren-Rodrguez, A; Contreras-Ochoa, C O; Estrada-Mondaca, S; Parra-Cabrera, M S

2008-08-01

427

The dopamine D3/D2 agonist (+)-PD-128,907 [(R-(+)-trans-3,4a,10b-tetrahydro-4-propyl-2H,5H-[1]benzopyrano[4,3-b]-1,4-oxazin-9-ol)] protects against acute and cocaine-kindled seizures in mice: further evidence for the involvement of D3 receptors.  

PubMed

Previous findings have demonstrated a protective role for dopamine D(3)/D(2) receptor agonists in the convulsant and lethal effects of acutely administered cocaine. Data are provided here to establish that the protection occurs through a D(3)-linked mechanism and that protection is extended to seizure kindling. The D(3) antagonist SB-277011-A [4-quinolinecarboxamide,N-[trans-4-[2-(6-cyano-3,4-dihydro-2(1H)-isoquinolinyl)ethyl]-cyclohexyl]-(9CI)] prevented the anticonvulsant effect of the D(3)/D(2) receptor agonist (+)-PD-128,907 [(R-(+)-trans-3,4a,10b-tetrahydro-4-propyl-2H,5H-[1]benzopyrano[4,3-b]-1,4-oxazin-9-ol)] on cocaine-induced seizures. The protection afforded by the D(3)/D(2) agonist, (+)-PD-128,907, was eliminated in D(3) receptor-deficient mice. In D(2) receptor knockout mice, the anticonvulsant effects of (+)-PD-128,907 were preserved. (+)-PD-128,907 also prevented the acquisition and expression of cocaine-kindled seizures engendered by repeated daily dosing with 60 mg/kg cocaine. (+)-PD-128,907 also blocked the seizures induced in mice fully seizure kindled to cocaine. Although repeated dosing with cocaine increased the potency of cocaine to produce seizures and lethality (decreased ED(50) values), daily coadministration of (+)-PD-128,907 significantly prevented this potency shift. In mice treated daily with cocaine and (+)-PD-128,907, the density, but not the affinity, of D(3) receptors was increased. The specificity with which (+)-PD-128,907 acts upon this cocaine-driven process was demonstrated by the lack of a significant effect of (+)-PD-128,907 on seizure kindling to a GABA(A) receptor antagonist, pentylenetetrazol. Taken together and with literature findings, the data indicate that dopamine D(3) receptors function in the initiation of a dampening mechanism against the toxic effects of cocaine, a finding that might have relevance to psychiatric disorders of drug dependence, schizophrenia, and bipolar depression. PMID:18566292

Witkin, J M; Levant, B; Zapata, A; Kaminski, R; Gasior, M

2008-06-19

428

Lewis Acid Organocatalysts  

NASA Astrophysics Data System (ADS)

The term Lewis acid catalysts generally refers to metal salts like aluminium chloride, titanium chloride and zinc chloride. Their application in asymmetric catalysis can be achieved by the addition of enantiopure ligands to these salts. However, not only metal centers can function as Lewis acids. Compounds containing carbenium, silyl or phosphonium cations display Lewis acid catalytic activity. In addition, hypervalent compounds based on phosphorus and silicon, inherit Lewis acidity. Furthermore, ionic liquids, organic salts with a melting point below 100 C, have revealed the ability to catalyze a range of reactions either in substoichiometric amount or, if used as the reaction medium, in stoichiometric or even larger quantities. The ionic liquids can often be efficiently recovered. The catalytic activity of the ionic liquid is explained by the Lewis acidic nature of their cations. This review covers the survey of known classes of metal-free Lewis acids and their application in catalysis.

Sereda, Oksana; Tabassum, Sobia; Wilhelm, Ren

429

Acid rain reports  

NASA Astrophysics Data System (ADS)

Three independent reports on acid precipitation issued in June reinforce each other and, taken together, support those seeking immediate action to curb man-generated acid deposition in northeastern North America by reducing emissions of sulfur and nitrogen oxides. The Interagency Task Force on Acid Precipitation report concluded that manmade pollution is to blame for acid precipitation problems in the northeastern United States. A National Research Council (NRC) committee stated that reducing the manmade emissions of sulfur and nitrogen oxides will result in a proportional reduction in the deposition of acid precipitation. And an acid rain panel assembled by the White House Office of Science and Technology Policy (OSTP) called for immediate action to curb the emissions despite incomplete scientific data.

Richman, Barbara T.

430

Contact sensitizers modulate the arachidonic acid metabolism of PMA-differentiated U-937 monocytic cells activated by LPS  

SciTech Connect

For the effective induction of a hapten-specific T cell immune response toward contact sensitizers, in addition to covalent-modification of skin proteins, the redox and inflammatory statuses of activated dendritic cells are crucial. The aim of this study was to better understand how sensitizers modulate an inflammatory response through cytokines production and COX metabolism cascade. To address this purpose, we used the human monocytic-like U-937 cell line differentiated by phorbol myristate acetate (PMA) and investigated the effect of 6 contact sensitizers (DNCB, PPD, hydroquinone, propyl gallate, cinnamaldehyde and eugenol) and 3 non sensitizers (lactic acid, glycerol and tween 20) on the production of pro-inflammatory cytokines (IL-1{beta} and TNF-{alpha}) and on the arachidonic acid metabolic profile after bacterial lipopolysaccharide (LPS) stimulation. Our results showed that among the tested molecules, all sensitizers specifically prevent the production of PMA/LPS-induced COX-2 metabolites (PGE{sub 2,} TxB{sub 2} and PGD{sub 2}), eugenol and cinnamaldehyde inhibiting also the production of IL-1{beta} and TNF-{alpha}. We further demonstrated that there is no unique PGE{sub 2} inhibition mechanism: while the release of arachidonic acid (AA) from membrane phospholipids does not appear do be a target of modulation, COX-2 expression and/or COX-2 enzymatic activity are the major steps of prostaglandin synthesis that are inhibited by sensitizers. Altogether these results add a new insight into the multiple biochemical effects described for sensitizers. - Highlights: > We investigated how contact sensitizers modulate an inflammatory response. > We used macrophage-differentiated cell line, U-937 treated with PMA/LPS. > Sensitizers specifically inhibit the production of COX metabolites (PGE2, TxB2). > Several mechanisms of inhibition: COX-2 expression/enzymatic activity, isomerases. > New insight in the biochemical properties of sensitizers.

Del Bufalo, Aurelia, E-mail: adelbufalo@rd.loreal.com [L'Oreal R and I, 93600 Aulnay-sous-Bois (France); Bernad, Jose; Dardenne, Christophe [UMD3, INSERM-IFR150, Universite de Toulouse, Universite Paul Sabatier, 31062 Toulouse (France); Verda, Denis; Meunier, Jean Roch; Rousset, Francoise; Martinozzi-Teissier, Silvia [L'Oreal R and I, 93600 Aulnay-sous-Bois (France); Pipy, Bernard [UMD3, INSERM-IFR150, Universite de Toulouse, Universite Paul Sabatier, 31062 Toulouse (France)

2011-10-01

431

Kidney amino acid transport  

Microsoft Academic Search

Near complete reabsorption of filtered amino acids is a main specialized transport function of the kidney proximal tubule.\\u000a This evolutionary conserved task is carried out by a subset of luminal and basolateral transporters that together form the\\u000a transcellular amino acid transport machinery similar to that of small intestine. A number of other amino acid transporters\\u000a expressed in the basolateral membrane

Franois Verrey; Dustin Singer; Tamara Ramadan; Raphael N. Vuille-dit-Bille; Luca Mariotta; Simone M. R. Camargo

2009-01-01

432

Chronic valproic acid intoxication.  

PubMed

Valproic acid intoxication may be associated with cerebral, cardiovascular, respiratory, gastrointestinal, and hematologic complications. We report a case of a 7-year-old girl, epilepsy-treated chronically with valproic acid, sulthiame, and clonazepam, who presented to the emergency room because of a global deterioration during the preceding 2 months, including poorer feeding and worsened general responsiveness. The girl was later diagnosed to have chronic valproic acid intoxication. PMID:23736073

Weiner, Dror; Nir, Vered; Klein-Kremer, Adi; Kassem, Eiass

2013-06-01

433

Acid rain on Bermuda  

Microsoft Academic Search

Increased acidity of precipitation due to combustion of fossil fuels has been well documented for both the eastern USA1 and Canada2. The SO2 and NOxemitted by the burning of coal, natural gas, fuel oil and petrol are oxidized in the atmosphere to sulphuric and nitric acids which subsequently give rise to acid precipitation1. However, the SO2 and NOx emitted, and

Timothy Jickells; Anthony Knap; Thomas Church; James Galloway; John Miller

1982-01-01

434

Preparation of petroselinic acid  

Microsoft Academic Search

Petroselinic acid of a grade which is suitable for most laboratory applications has been prepared by a single crystallization\\u000a of the mixed fatty acids of parsley seed oil from 90% ethanol. A product of higher purity has been prepared from this acid\\u000a by application of urea segregation techniques for the removal of saturated materials. No evidence of the presence of

Sara P. Fore; Raiford L. Holmes; W. G. Bickford

1960-01-01

435

Well acidization with alpha-hydroxysulfonic acid  

SciTech Connect

This patent describes a well treating process in which fluid is injected into a well and flowed into contact with acidifiable material in and around a portion of the well within a subterranean earth formation in order to contact the acidifiable material with at least one strong acid. An improved process for controlling the rate of the acidification reaction comprises: flowing fluid inclusive of water, SO/sub 2/ and carbonyl compound into the well and into and out of contact with the acidifiable material with the composition of the fluid arranged so that, in contact with the acidifiable material, the fluid consists essentially of an acidic solution of water, SO/sub 2/ and carbonyl compound in equilibrium with at least one reactively formed alpha-hydroxysulfonic acid.

Slaugh, L.H.

1987-06-02

436

Aristolochic Acid: Safety Alert  

Center for Food Safety and Applied Nutrition (CFSAN)

... Section Contents Menu. Recalls, Outbreaks & Emergencies. Safety Alerts & Advisories. -. Aristolochic Acid: Safety Alert. FDA ... More results from www.fda.gov/food/recallsoutbreaksemergencies/safetyalertsadvisories

437

Recovery of organic acids  

SciTech Connect

A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. A tertiary amine and CO.sub.2 are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and an amine. A water immiscible solvent, such as an alcohol, is added to extract the acid/amine complex from the dilute salt solution to a reaction phase. The reaction phase is continuously dried and a product between the acid and the solvent, such as an ester, is formed.

Verser, Dan W. (Menlo Park, CA); Eggeman, Timothy J. (Lakewood, CO)

2011-11-01

438

Recovery of organic acids  

DOEpatents

A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. A tertiary amine and CO.sub.2 are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and an amine. A water immiscible solvent, such as an alcohol, is added to extract the acid/amine complex from the dilute salt solution to a reaction phase. The reaction phase is continuously dried and a product between the acid and the solvent, such as an ester, is formed.

Verser, Dan W. (Golden, CO); Eggeman, Timothy J. (Lakewood, CO)

2009-10-13

439

Acidizing concentrates for oil well acidizing systems  

SciTech Connect

An acidizing composition is described for treating oil-bearing formations comprising: (a) from about 90 to about 99.99 percent by volume of an aqueous acid solution; and (b) from about 0.01 to about 10 percent by weight of an acidizing concentrate consisting of: a mixture of a branched-aliphatic C/sub 3/-C/sub 6/ alcohol and a branched aliphatic C/sub 7/-C/sub 10/ alcohol; and an effective amount of a non-ionic polyether surfactant to render the alcohols soluble in the acid. The surfactant has the formula: R is the oxyalkylation residue of a C/sub 2/-C/sub 10/ diol or triol; n is an integer of 2 or 3, X and Y are numbers such that the ratio of X to Y is from 8:1 to 0.3:1; and the total molecular weight of the molecule is from 1,000 to 15,000. The weight ratio of the mixture of alcohols to the nonionic surfactant is from 10:1 to 1:10. The composition is capable of dissolving sludge deposits in the oil-bearing formations.

Crema, S.C.

1987-06-30

440

2-substituted thiazolidine-4(R)-carboxylic acids as prodrugs of L-cysteine. Protection of mice against acetaminophen hepatotoxicity  

SciTech Connect

A number of 2-alkyl- and 2-aryl-substituted thiazolidine-4(R)-carboxylic acids were evaluated for their protective effect against hepatotoxic deaths produced in mice by LD/sub 90/ doses of acetaminophen. 2(RS)-Methyl-, 2(RS)-n-propyl-, and 2(RS)-n- pentylthiazolidine -4(R)-carboxylic acids (compounds 1b,d,e, respectively) were nearly equipotent in their protective effect based on the number of surviving animals at 48 h as well as by histological criteria. 2(RS)-Ethyl-, 2(RS)-phenyl-, and 2(RS)-(4-pyridyl)thiazolidine-4(R)-carboxylic acids (compounds 1c,f,g) were less protective. The enantiomer of 1b, viz., 2(RS)- methylthiazolidine -4(S)-carboxylic acid (2b), was totally ineffective in this regard. Thiazolidine-4(R)-carboxylic acid (1a), but not its enantiomer, 2a, was a good substrate for a solubilized preparation of rat liver mitochondrial proline oxidase (K/sub m/ 1.1 x 10(-4) M; V/sub max/ . 5.4 mumol min-1 (mg of protein)-1). Compound 1b was not a substrate for proline oxidase but dissociated to L-cysteine in this system. At physiological pH and temperature, the hydrogens on the methyl group of 1b underwent deuterium exchange with solvent D/sub 2/O (k1 . 2.5 X 10(-5) s), suggesting that opening of the thiazolidine ring must have taken place. Indeed, 1b labeled with /sup 14/C in the 2 and methyl positions was rapidly metabolized by the rat to produce /sup 14/CO/sub 2/, 80% of the dose being excreted in this form in the expired air after 24 h. It is suggested that these 2-substituted thiazolidine-4(R)-carboxylic acids are prodrugs of L-cysteine that liberate this sulfhydryl amino acid in vivo by nonenzymatic ring opening, followed by solvolysis.

Nagasawa, H.T.; Goon, D.J.; Muldoon, W.P.; Zera, R.T.

1984-05-01

441

Strong Acids (GCMP)  

NSDL National Science Digital Library

Strong Acids: this is a resource in the collection "General Chemistry Multimedia Problems". This problem will explore the properties of common strong acids. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

442

Acids and Salts (GCMP)  

NSDL National Science Digital Library

Acids and Salts: this is a resource in the collection "General Chemistry Multimedia Problems". This problem will explore a few properties of common acids and their salts. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

443

Facts about Folic Acid  

MedlinePLUS

... INFO (800-232-4636) TTY: (888) 232-6348 Contact CDC-INFO flo@cdc.gov Folic Acid Homepage Facts Quiz Questions & Answers Cereals with Folic Acid Data and Statistics Research Global Initiative Articles & Key Findings Recommendations Free Materials Links ...

444

Folic Acid Quiz  

MedlinePLUS

... INFO (800-232-4636) TTY: (888) 232-6348 Contact CDC-INFO flo@cdc.gov Folic Acid Homepage Facts Quiz Questions & Answers Cereals with Folic Acid Data and Statistics Research Global Initiative Articles & Key Findings Recommendations Free Materials Links ...

445

Acid rain options  

SciTech Connect

A number of contributions made to a series of seminars on acid rain options held by the Air Pollution Control Association are presented. They include statements on US and Canadian policy and legislation, and views from coal producers, electric utilities and motor vehicle manufacturers on measures to counteract or prevent the effects of acid rain.

Perhac, R.M.

1985-03-01

446

Azelaic Acid Topical  

MedlinePLUS

Finacea Gel ... Azelaic acid gel is used to clear the bumps, lesions, and swelling caused by rosacea (a skin disease that causes redness, ... Azelaic acid comes as a gel and a cream to apply to the skin. It is usually applied twice a day, in the morning and the evening. ...

447

EFFECTS OF ACID PRECIPITATION  

EPA Science Inventory

Recent reviews of available data indicate that precipitation in a large region of North America is highly acidic when its pH is compared with the expected pH value of 5.65 for pure rain water in equilibrium with CO2. A growing body of evidence suggests that acid rain is responsib...

448

(Acid rain workshop)  

Microsoft Academic Search

The traveler presented a paper entitled Susceptibility of Asian Ecosystems to Soil-Mediated Acid Rain Damage'' at the Second Workshop on Acid Rain in Asia. The workshop was organized by the Asian Institute of Technology (Bangkok, Thailand), Argonne National Laboratory (Argonne, Illinois), and Resource Management Associates (Madison, Wisconsin) and was sponsored by the US Department of Energy, the United Nations Environment

1990-01-01

449

Acid in water  

NSDL National Science Digital Library

Plants and animals that live in water create some amount of acid in the water. The carbon dioxide that plants and animals release into the water makes the water acidic and unsafe for living organisms. This is why the water of captive aquatic animals and plants must be changed often.

Laszlo Ilyes (None;)

2007-05-16

450

Amino acids: Analytical aspects  

Microsoft Academic Search

This workshop was organized as a direct response to concerns and queries raised by laboratory personnel, both in Europe and in the United States, about the imminent withdrawal of Beckman Coulter from the amino acid analysis market. The topics covered included external quality control schemes, standard operating procedures for amino acid analysis and instrumentation, both from a user's perspective and

P. D. Mayne; G. Roche; D. Deverell

2001-01-01

451

EXPOSURES TO ACIDIC AEROSOLS  

EPA Science Inventory

Ambient monitoring of acid aerosol in four U.S. cities and in a rural region of southern Ontario clearly show distinct periods of strong acidity. easurements made in Kingston, TN, and Stuebenville, OH, resulted in 24-hr H+ ion concentrations exceeding 100 nmole/m3 more than 10 ti...

452

Toxicology of Perfluoroalkyl acids  

EPA Science Inventory

The Perfluoroalkyl acids(PFAAs) area a family of organic chemicals consisting of a perflurinated carbon backbone (4-12in length) and a acidic functional moiety (Carboxylate or sulfonate). These compounds have excellent surface-tension reducing properties and have numerous industr...

453

Toxicology of Perfluoroalkyl Acids*  

EPA Science Inventory

The perfluoroalkyl acids (PFAAs) are a family of organic chemicals consisting of a perfluorinated carbon backbone (4-12 in length) and an acidic functional moiety (carboxylate or sulfonate). These compounds are chemically stable, have excellent surface-tension reducing properties...

454

Fats and fatty acids  

Technology Transfer Automated Retrieval System (TEKTRAN)

The absolute fat requirement of the human species is the amount of essential fatty acids needed to maintain optimal fatty acid composition of all tissues and normal eicosanoid synthesis. At most, this requirement is no more than about 5% of an adequate energy intake. However, fat accounts for appro...

455

Metabolism of Acid Mucopolysaccharides  

PubMed Central

The biosynthesis of the acid mucopolysaccharides, hyaluronic acid and chondroitin sulfuric acid, occurs by way of uridine nucleotides which contain the monosaccharide units of the respective polysaccharides. The mechanism of alternation of groups is as yet unknown. Certain of the acid mucopolysaccharides are covalently bound to protein by way of serine. In the case of the protein-polysaccharide complex of cartilage, there is evidence to suggest that the polysaccharide may be linked to the serine by way of galactose. Chondroitin sulfuric acid B may be isolated almost free of amino acids from the tissues and urine of patients with the Hurler syndrome without the use of proteolytic enzymes, acid, or alkali. This contrasts markedly with the tight binding of this compound to protein in normal tissue. It is suggested that the metabolic defect in this disease may reside in a defect of the peptide or linkage of the peptide to polysaccharide resulting in failure of the acid mucopolysaccharide to be fixed normally in connective tissue. Such a defect may result in interference with normal regulation of polysaccharide synthesis with a resultant increased synthesis. It is proposed that such a mechanism may obtain in other heritable connective tissue diseases as well as other storage diseases.

Dorfman, Albert

1964-01-01

456

Amino Acid Crossword Puzzle  

ERIC Educational Resources Information Center

|Learning the 20 standard amino acids is an essential component of an introductory course in biochemistry. Later in the course, the students study metabolism and learn about various catabolic and anabolic pathways involving amino acids. Learning new material or concepts often is easier if one can connect the new material to what one already knows;

Sims, Paul A.

2011-01-01

457