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PubMed1987

Purification and characterization of calmodulin-dependent functional protein, phosphodiesterase, in the lens.

Calmodulin and calmodulin-dependent functional protein play an important role in the maintenance of lens transparency and homeostasis. In the present study, phosphodiesterase, one of the typical calmodulin-dependent functional proteins, was purified from bovine lens by DEAE-cellulose chromatography, calmodulin-Sepharose 4B chromatography and Superose 12 chromatography. Moreover, calmodulin-dependent phosphodiesterase, and independent phosphodiesterase were separated from crude lens extract using DEAE-cellulose column. The calmodulin-dependent phosphodiesterase was purified 4500-fold with a 0.7% yield; it was a dimer formed with two single polypeptides of 59K as the molecular weight. The enzyme had a higher affinity for cyclic GMP than for cyclic AMP, and functioned at calcium ion concentration above 10(-6) M in the incubation mixture. W-7 as calmodulin antagonist indirectly inhibited the enzyme activity and nifedipine as calmodulin-dependent phosphodiesterase antagonist directly inhibited the enzyme activity. These results suggest that an appearance of calmodulin-dependent phosphodiesterase activity depends on the interrelation between the calcium ion and calmodulin in the lens.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed2006

Pharmacophoric 2-hydroxyalkyl benzenesulfonamide: a single-step synthesis from benzenesulfonamide via hemiaminal.

ortho-Acylation attempt of benzenesulfonamide afforded the corresponding hemiaminal as major product. The in situ reduction of the reaction mixture, reported herein, directly provided 2-hydroxyalkyl benzenesulfonamide, an important pharmacophoric element for designing drug-like scaffolds. Its application is demonstrated through designing a novel series of 1,5-diarylpyrazoles for cyclooxygenase-2 (COX-2) inhibition.

Aldehydes↗

PubMed1991

Rapid assay for the quantification of piretanide in biological fluids.

Piretanide was determined from plasma and urine using reversed-phase high-performance liquid chromatography. Plasma was extracted with diethylether at pH 4 using bumetanide as internal standard. The chromatographic separation was performed on an octadecylsilane column (ODS) with acetonitrile/pH 7 phosphate buffer (3:7, v/v). In order to determine piretanide in urine, bumetanide was added to a urine aliquot. Then the sample was centrifuged and the supernatant directly injected without extraction followed by chromatography on an ODS column with a mixture of methanol and pH 7 phosphate buffer (12:13, v/v). The compounds were detected by their intrinsic fluorescence, monitoring the eluate at 287/450 nm. Total chromatography times were 8 min for plasma and 13 min for urine samples. The method was applied for the assay of piretanide in plasma of healthy volunteers after i.v. or p.o. dosage of 6 mg piretanide.

Administration, Oral↗

PubMed2005

An improved method for proteomics studies in C. elegans by fluorogenic derivatization, HPLC isolation, enzymatic digestion and liquid chromatography--tandem mass spectrometric identification.

An improved method for proteomics studies, which includes the fluorogenic derivertization of protein mixtures with 7-chloro-4-(dimethylaminoethylaminosulfonyl)-2,1,3-benzoxadiazole (DAABD-Cl), followed by HPLC isolation, enzymatic digestion and identification of the derivatized proteins by HPLC-electrospray ionization (ESI)-MS/MS with the probability-based protein identification algorithm, identified 103 proteins in the soluble extract (10 microg protein) of Caenorhabditis elegans.

Algorithms↗

PubMed1995

High-performance micellar liquid chromatography determination of sulphonamides in pharmaceuticals after azodye precolumn derivatization.

A chromatographic procedure with precolumn derivatization to form the N-(1-naphthyl)ethylenediamine dihydrochloride azodyes is proposed for the analysis of several sulphonamides (sodium sulphacetamide, sulphadiazine, sulphaguanidine, sulphamerazine, sulphamethizole, sulphamethoxazole, sulphanilamide and sulphathiazole) in pharmaceutical preparations (tablets, pills, capsules, suspensions and drops). The separation is performed with a 0.05 M sodium dodecyl sulphate/2.4% pentanol eluent at pH 7. The precolumn derivatization improved the resolution in the chromatograms and increased the selectivity in the determination of mixtures of sulphonamides and in preparations where other drugs were present. The derivatization reaction was readily performed in a micellar medium of SDS at pH 1, leading to a rapid and simple procedure. The recoveries were in the 97-104% range with relative standard deviations usually below 3%.

Azo Compounds↗

PubMed1996

Sensitive analytical method for the novel H1-receptor antagonist HSR-609 in human plasma and urine by high-performance liquid chromatography with pre-column fluorescent derivatization.

A simple and sensitive method for quantitation of HSR-609 (I) in human plasma and urine was developed using HPLC with the fluorescence labelling reagent 4-(N,N-dimethylaminosulfonyl)-7-N-piperazino-2,1,3-benzox adi azole (DBD-PZ). Compound I was extracted from human plasma and urine, and derivatized by reaction with DBD-PZ in the presence of Mukaiyama reagent A, an equimolar solution of 2,2'-dipyridyl disulfide (DPDS) and triphenylphosphine (TPP) in acetonitrile. The reaction mixture was cleaned up by liquid liquid extraction following the derivatization. The conjugate was analyzed by ion-pair-HPLC with fluorometric detection. The quantitation limits for I were 0.5 ng/ml in plasma and 5 ng/ml in urine. Using this method, plasma concentration and urinary excretion of I were studied after oral administration of I to human volunteers.

Benzoxepins↗

PubMedDate not supplied

High-performance liquid chromatography with fluorescence detection of ebiratide using 4-(N,N-dimethylamino-sulphonyl)-7-fluoro-2,1,3-benzoxadiazole as a fluorogenic reagent.

A sensitive high-performance liquid chromatography (HPLC) method with fluorescence detection has been developed and applied to the determination of ACTH4-9 analogue (ebiratide). 4-(N,N-Dimethylamino-sulphonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F) was used as a fluorogenic labelling reagent. Ebiratide in 0.1 M borate buffer (pH 9.0) was reacted with DBD-F in acetonitrile solution at 50 degrees C for 30 min. After cooling, the mixture was separated by a reversed-phase HPLC. Then DBD-ebiratide was monitored at 580 nm with the excitation at 440 nm. The calibration curve was linear up to 10 pmol on column (r = 0.999) with the detection limit of 0.25 pmol (signal-to-noise = 3).

Adrenocorticotropic Hormone↗

PubMed2001

Exact mass measurements on-line with high-performance liquid chromatography on a quadrupole mass spectrometer.

Exact mass measurements were performed on-line with high-performance liquid chromatography on a quadrupole mass spectrometer. Compounds with molecular weights from 98 to 797, mainly aromatic sulfonates and sulfonamides, were analyzed with electrospray ionization in positive or negative mode. Internal mass calibration compounds were continuously added after separation. A Gaussian fit of the mass errors of 808 individual measurements (concentrations of 1-10 mg/L, 20-200 ng absolute on column) resulted in a mean error of 0.1 mmu (0.45 ppm) and a standard deviation sigma of 1.5 mmu (5.4 ppm). The 99.7% confidence intervals (3sigma) were +/-4.5 mmu (+/-16.2 ppm) for single mass measurements. Averaging 10 measurements further reduced the errors to less than +/-1.5 mmu (+/-5 ppm). Isobaric interferences with ions resulting from the mass calibrants were avoided by the use of complementary mass calibrants. The results were verified (differences below +/-4.5 mmu) with a LC/ oa-TOFMS. Limited mass range chromatograms were used to enhance selectivity in the analysis of mixtures. The method was applied to determine the elemental composition of a potential dye metabolite detected in anaerobically treated textile wastewater.

Journal Article↗

PubMed2002

Phenotypic and genotypic HIV-1 drug resistance assays provide complementary information.

To determine the extent to which genotype (GT) or phenotype (PT) methods provide HIV-1 drug resistance information that is overlapping or complementary, both tests were performed on 1378 patient plasma samples. Discordance, defined as determination of reduced susceptibility measured by PT but sensitivity by GT (PT-R/GT-S), or vice versa (PT-S/GT-R), was common: 83, 62, 43, and 28% of samples with evidence of drug resistance had at least 1, 2, 3, or 4 drugs discordant, respectively. Three types of discordance were observed: PT-R/GT-S, and PT-S/GT-R with or without the presence of mixtures at resistance-associated positions (25%, 34%, and 41% of all discordance, respectively). After accounting for mixtures, results for didanosine (30%), zalcitabine (18%), tenofovir (17%), abacavir (14%), lamivudine (12%), and amprenavir (11%) were discordant in >or= 10% of samples. PT-S/GT-R results were most common for didanosine and zalcitabine, whereas PT-R/GT-S results were most common for lamivudine and amprenavir. PT provided quantitative assessment of the degree of reduced susceptibility and identified reduced susceptibility (PT-R/GT-S) or normal susceptibility (PT-S/GT-R) that was not recognized by the GT interpretation algorithm. GT provided valuable information when mixtures were present and minor populations of drug resistant virus were not detected by phenotyping (PT-S/GT-R results). This demonstrates the complementary nature of information provided by PT and GT tests and suggests that their combined use can provide additional clinically-relevant information.

Adenine↗

PubMed2004

Chiral separation of tamsulosin isomers by HPLC using cellulose tris (3,5-dimethhylphenylcarbamate) as a chiral stationary phase.

A high-performance liquid chromatographic (HPLC) method was developed for the chiral separation of an antagonist of alpha1A adrenoceptors, tamsulosin and its S-isomer. Baseline separation of the isomers was achieved within 35 min on a CHIRALCEL OD-RH column with a binary solvent mixture of 50 mmol l(-1) KPF6-acetonitrile (v/v (70:30), pH 5.0) as the optimized mobile phase. The detection limits and quantification limits of both R-isomer and S-isomer were 0.11 and 0.44 ng, respectively. The R.S.D. values of peak-area for the two isomer were 0.42% (of peak-height: 0.77%) for R-isomer and 0.64% (of peak-height:0.92%) for S-isomer (n = 5).

Carbamates↗

PubMed2005

Water purification from organic pollutants by optimized micelle-clay systems.

Removal of anionic pollutants (imazaquin, sulfentrazone, sulfosulfuron) and neutral pollutants (alachlor, acetochlor, chlorotoluron, bromacil) from water by micelles preadsorbed on montmorillonite was studied. Micelles of octadecyltrimethylammonium and benzyldimethylhexadecylammonium (BDMHDA) were used. The micelle-clay systems (1% w/w) removed 87-99% of the pollutants from their water solutions containing 1-33 mg/L of herbicide. The nature of the headgroup of the organic cation, which forms the micelles, is critical. Desorption of imazaquin and acetochlor from 0.3% (w/w) suspension of BDMHDA-clay complex after 24 h was around 7% in the range of adsorbed amounts from 0.6 to 15.3 mg/g. These results indicate rather slow rates and small extents of release of pollutants from micelle-clay complexes. Column filters (25 cm) made of a mixture of quartz sand and BDMHDA micelle-clay complex at 100:1 w/w ratio removed at least 99% of above pollutants from initial solutions containing 10 mg/L; 99.5 and 97% of sulfosulfuron and alachlor were removed from their initial solutions containing 200 and 5 microg/L, respectively. These data indicate that micelle-clay complexes are very efficient for water purification from organic contaminants.

Bentonite↗

PubMed2005

A new stability--indicating RP-HPLC method to determine assay and known impurity of Celecoxib API.

A simple, rapid and accurate Reverse Phase High-Performance Liquid Chromatography (RP-HPLC) method was developed to determine assay and known impurity of Celecoxib API. The chromatographic separation was performed on reversed-phase C-18 column. Eluents were monitored on photo-diode array detector at a wavelength of 254 nm using a mixture (40:60) of buffer and acetonitrile. Solution concentrations were measured on a weight basis to avoid the use of an internal standard. The method was statistically validated for forced-degradation study, linearity and range, accuracy, precision, stability of analytical solutions, and selectivity. Due to its simplicity, rapid, and accuracy, we believe that the method will be useful to determine assay and known impurity of Celecoxib.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1976

Otitis media of infancy and early childhood. A double-blind study of four treatment regimens.

A double-blind, randomized trial of four antimicrobial regimens was conducted in 383 infants and children with acute otitis media. The drugs used were penicillin V, amoxicillin trihydrate, erythromycin estolate, and erythromycin estolate with trisulfapyrimidines. Aspiration of middle ear fluid for culture was done before treatment and repeated during treatment if fluid persisted. Etiologic bacteria were most commonly pneumococci (31%) or Haemophilus sp (22%), and an additional 5% of patients had both organisms. Amoxicillin was the most effective in promoting initial response in pneumococcal infection. For Haemophilus infections, the cure rates with amoxicillin and the erythromycin-trisulfapyrimidines mixture were significantly better than with the other two regimens, and serous otitis did not occur during the follow-up period; however, new episodes of otitis were comparable in the four groups. Amoxicillin and the erythromycin estolate-trisulfapyrimidines combination appear to be somewhat more effective than penicillin V or erythromycin estolate.

Acute Disease↗

PubMed2004

Multiple comparisons with a control in families with both one-sided and two-sided hypotheses.

Comparing several treatments with a control is a common objective of clinical studies. However, existing procedures mainly deal with particular families of inferences in which all hypotheses are either one- or two-sided. In this article, we seek to develop a procedure which copes with a more general testing environment in which the family of inferences is composed of a mixture of one- and two-sided hypotheses. The proposed procedure provides a more flexible and powerful tool than the existing method. The superiority of this method is also substantiated by a simulation study of average power. Selected critical values are tabulated for the implementation of the proposed procedure. Finally, we provide an illustrative example with sample data extracted from a medical experiment.

Aged↗

PubMed2003

Rational design, synthesis and structure-activity relationships of a cyclic succinate series of TNF-alpha converting enzyme inhibitors. Part 1: lead identification.

Rational design based on the broad spectrum MMP inhibitor CGS 27023A led to the identification of a novel series of cyclic succinate TACE inhibitors. As a mixture of two enantiomers, the lead compound 17b exhibited potent enzyme activity (IC(50)=8 nM) in the inhibition of porcine TNF-alpha converting enzyme (pTACE) and excellent selectivity over aggrecanase and MMP-1, -2 and -9.

ADAM Proteins↗

PubMed2006

H-89 potentiates adipogenesis in 3T3-L1 cells by activating insulin signaling independently of protein kinase A.

Among four kinds of protein kinase A (PKA) inhibitors tested, H-89 exhibited a unique action to remarkably enhance adipocyte differentiation of 3T3-L1 cells, whereas the other three PKA inhibitors, PKA inhibitor Fragment 14-22 (PKI), Rp-cAMP, and KT 5720, did not enhance adipocyte differentiation. H-85, which is an inactive form of H-89, exhibited a similar enhancing effect on adipocyte differentiation. H-89 also potentiated the phosphorylation of Akt and extracellular signal-regulated kinase (ERK) 1/2 in 3T3-L1 cells, which function as downstream signaling of insulin. Phosphoinositide 3-kinase (PI3K) inhibitor wortmannin and mitogen-activated protein kinase kinase (MEK) inhibitor PD 98059 suppressed both the H-89-induced promotion of adipocyte differentiation and the H-89-induced potentiation of phosphorylation of Akt and ERK1/2. Rho kinase inhibitor Y-27632 also promoted the phosphorylation of both Akt and ERK1/2 and enhanced adipocyte differentiation, although its effect was somewhat less than that of H-89. Even when cells were treated with a mixture of Y-27632 and H-89, the additive enhancing effects on both the insulin signaling and adipocyte differentiation were not detected. Therefore, it is suggested that the major possible mechanism whereby H-89 potentiates adipocyte differentiation of 3T3-L1 cells is activation of insulin signaling that is elicited mostly by inhibiting Rho/Rho kinase pathway.

3T3-L1 Cells↗

PubMed2002

Dissipation of nicosulfuron and rimsulfuron in surface soil.

Field and soil fortification studies were conducted to evaluate the half-lives (DT(50)) of nicosulfuron and rimsulfuron in a Sequatchie silt loam surface soil. The dissipation of each herbicide was also evaluated with the two compounds applied simultaneously, which is a typical application method used in corn production. Field studies in two years indicated that both herbicides alone and in mixture disappeared quickly, with all DT(50) < 6 days. Environmental conditions including warm, moist soil, and a soil pH of 5.7 encouraged rapid herbicide dissipation. Rapid degradation was observed under laboratory conditions using this same soil, with all DT(50) < 3 days. This research indicated minimal risk of carry-over to subsequent rotational crops and minimal residual weed control from these herbicides when applied to a silt loam soil under ambient climatic conditions in Tennessee.

Half-Life↗

PubMed2003

High performance liquid chromatographic method for residue determination of sulfosulfuron.

A method was developed for sulfosulfuron [(1-(2-ethylsulfonylimidazo [1,2-a] pyridin-3-ylsulfonyl)-3-(4,6-dimethoxy pyrimidin-2yl)] and its three major metabolites by HPLC utilizing photodiode array detector. The method makes use of Lichrosphere RP-8 column and acetonitrile:water:orthophosphoric acid (80:20:0.1 v/v/v) as mobile phase at a flow rate of 1 ml min(-1). Using these condition sulfosulfuron, and compounds II, III and IV were resolved with distinct Rt of 2.088, 2.216, 2.302 and 2.476 minutes, respectively. Sulfosulfuron residues were analysed in soil, wheat grain and straw samples by extracting with a mixture of acetonitrile and 2 M ammonium carbonate (100 ml, 9:1, v/v) using horizontal shaker for soil and Soxhlet apparatus for wheat grain and straw samples. The extracts were cleaned up by partitioning with dichloromethane in case of soil and hexane followed by dichloromethane for plant samples. The percent recovery ranged between 71 to 75.2 for soil and 70.8 to 74.7 for plant samples. The limit of determination of sulfosulfuron was 0.25 microg g(-1).

Chromatography, High Pressure Liquid↗