bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative knowledge management: A pilot study of Chinese and American universities
Authors: Geng Qian , Townley Charles , Huang Kun , Zhang Jing
Published: May 2005

Comparative study of knowledge management (KM) promises to lead to more effective knowledge use in all cultural environments. This pilot study compares KM priorities, needs, tools, and administrative structure components in large Chinese and American universities. General KM theory and literature related to KM in higher education are analyzed to develop the four components of the study. Comparative differences in KM practice at large Chinese and American universities are analyzed for each component. A correlation matrix reveals statistically significant co‐variation among all but one of the study components. Four conclusions related to comparative KM and suggestions for future research are presented.
Comparative pharmacokinetics of two tablet formulations of Losartan: bioequivalence assessment
Authors: Tamimi J.J.I. , Salem I.I. , Mahmood Alam S. , Zaman Q. , Dham Ruwayda
Published: May 2005

The pharmacokinetic profiles of two brands of losartan 50 mg tablets were compared in 24 healthy adult volunteers after a single oral dose in a randomized cross‐over study. The study was conducted at the ACDIMA Center for Bioequivalence & Pharmaceutical Studies, Amman, Jordan. The reference (Cozaar, MSD, The Netherlands) and test (Blosart, Julphar, UAE) products were administered to fasting volunteers. Blood samples were collected at specified time intervals, and the plasma separated and analysed for losartan and its active metabolite (losartan carboxylic acid) using a validated HPLC method with fluorescence detection. Pharmacokinetic parameters AUC0−t, AUC0−α, Cmax, Tmax, T1/2, elimination rate constant, MRT, Cl/F and Vss/F were determined from plasma concentration‐time profiles of both formulations and found to be in good agreement with reported values. Three parameters (AUC0−t, AUC0−α, and Cmax) were compared statistically to evaluate the bioequivalence between the two brands, using statistical modules recommended by the FDA. Analysis of variance (ANOVA) did not show any significant difference between the two formulations and 90% confidence intervals fell within the acceptable range (80%–125%) for bioequivalence. Based on these statistical inferences it was concluded that the two formulations exhibited comparable pharmacokinetic profiles and that Julphar's Blosart is bioequivalent to Cozaar of MSD, The Netherlands. Copyright © 2005 John Wiley & Sons, Ltd.
Variable omeprazole kinetics in healthy Jordanian adults
Authors: Albsoul‐Younes Abla , Tayyem Rabab , Najib Naji
Published: May 2005

Objectives. The objective of this study was to examine the pharmacokinetics of orally administered omeprazole in healthy adult Jordanian men.

Method. Plasma concentrations of omeprazole were measured over a 12 h period after administration of a single oral dose of 40 mg omeprazole (Losec®, AstraZeneca, UK). Subjects were healthy adult Jordanian men age 18–38 (24±4, mean±SD). The pharmacokinetic parameters were derived from the plasma concentration‐time profiles for AUC0‐t, AUC0‐inf, Cmax, tmax, t1/2e and Ke.

Results. The pharmacokinetic of omeprazole were scattered over a wide range. The median AUC0‐inf was 784.86±1182.88 (ng·h/ml), and the median Cmax was 521±354 (ng/ml) (median±SD). In general, most subjects showed normal distribution (∼90%). Some subjects (10%) did show very high AUC and Cmax compared with the reported AUC and Cmax levels. These subjects had higher half‐lives and lower rates of elimination.

Conclusion. Significant difference in the pharmacokinetics of omeprazole after a single dose administration was noted. Approximately 10% of the study group showed very high omeprazole plasma levels and AUCs. Differences in the pharmacokinetics might be due to differences in the genetic make‐up of subjects. Copyright © 2005 John Wiley & Sons, Ltd.
The influence of weight with assay error on gentamicin pharmacokinetics using the Bayesian and nonlinear least square regression analysis in appendicitis patients
Authors: Burm Jin Pil
Published: May 2005

The purpose of this study was to determine the influence of weight with gentamicin assay error on the Bayesian and nonlinear least squares regression analysis in 12 Korean appendicitis patients. Gentamicin was administered intravenously over 0.5 h every 8 h. Three specimens were collected 48 h after the first dose from all patients at the following times, just before the regularly scheduled infusion, at 0.5 h and 2 h after the end of the 0.5 h infusion. Serum gentamicin levels were analysed by fluorescence polarization immunoassay technique with TDxFLx. The standard deviation (SD) of the assay over its working range had been determined at the serum gentamicin concentrations of 0, 2, 4, 8, 12 and 16 µg/ml in quadruplicate. The polynominal equation of gentamicin assay error was found to be SD (µg/ml)=0.0246−(0.0495C)+(0.00203C2). There were differences in the influence of weight with gentamicin assay error on pharmacokinetic parameters of gentamicin using the nonlinear least squares regression analysis but there were no differences on the Bayesian analysis. This polynominal equation can be used to improve the precision of fitting of pharmacokinetic models to optimize the process of model simulation both for population and for individualized pharmacokinetic models. The result would be improved dosage regimens and the better, safer care of patients receiving gentamicin. Copyright © 2005 John Wiley & Sons, Ltd.
Novel reactive perstraction system applied to the hydrolysis of penicillin G
Authors: Wyss A. , Seitert H. , von Stockar U. , Marison I.W.
Published: May 2005

The activity of penicillin acylase has been studied in aqueous and organic solvents, as free enzyme as well as immobilized within the membrane of liquid‐core capsules. The activity of the enzyme is inhibited by the accumulation of the products of the hydrolysis reaction, namely phenyl acetic acid (PAA). In order to overcome this inhibition a range of organic solvents were tested for use in in situ product recovery. Of these solvents dibutyl sebacate (DBS) was chosen due to the rapid extraction rate, the high logP and to facilitate capsule production. The extraction efficiency at pH 3.5 for PAA was >80% for phase ratios of >50% free solvent with partition coefficients of 8 and 0.7 for PAA and penicillin G (PenG), respectively, thereby showing that PAA could be selectively extracted at pH 3.5 and 25°C. Liquid‐core capsules containing DBS were shown to efficiently remove PAA selectively and the PAA could be effectively back‐extracted and the capsules re‐used in a three‐stage process resulting in high product separation. Immobilization of penicillin acylase onto the capsule membranes resulted in increased operational stability of the enzyme and a very high enzyme activity. Over 53.3% of the PAA formed could be recovered in the capsule core with a concentration over sevenfold higher than in the aqueous phase. Higher extraction efficiencies could be obtained by varying the substrate concentration and number of capsules. The enzyme immobilized on capsules could be stored for over 4 months at pH 8 and 4°C with no loss of activity. Over 80% of the initial activity could be recovered over five repeated batch cycles of the bioconversion process. The importance of capsular perstraction and reactive capsular perstraction has been clearly demonstrated. © 2005 Wiley Periodicals, Inc.
Determination of clozapine and its metabolites in serum and urine by reversed phase HPLC
Authors: Zeren Wang , Minglian Lu , Peipei Xu , Yanlin Zeng , Yanlin Zeng
Published: May 2005

A rapid, specific and sensitive method using reversed phase HPLC for the simultaneous determination of clozapine and its two metabolites in serum and urine has been developed. The mobile phase was a mixture of 67% (v/v) methanol in water containing 0.4% tetramethylethylenediamine and 0.32% acetic acid (pH 5.5). The influence of methanol content, the pH of the mobile phase and the effect of adding alkylammonium ions as peak tailing reducer in the mobile phase have been investigated. The solvent for extracting clozapine from serum and urine was ether. 50 μ1 of 0.25 M H2SO4 solution was used to redissolve the dry residue to eliminate the endogenous compounds which could otherwise be eluted together with clozapine from the HPLC column. The analysis of a single sample was accomplished within half an hour. The identities of the chromatographic peaks of clozapine and its N‐demethyl metabolite collected from the patient urine sample were confirmed by mass spectrometry. The method is sufficiently sensitive (5 ng/ml) and reproducible (CV 2.9%–6.7%) for clinical and pharmacokinetic studies, and preliminary results in these respects are presented.
Metabolic profiling of opioid peptides in canine pituitary and selected brain regions using HPLC with a radioreceptor assay detector
Authors: Takeshita Hisayoshi , Desiderio Dominic M. , Fridland Genevieve
Published: May 2005

A combination of gradient reversed‐phase high performance liquid chromatography (RP/HPLC) with a radioreceptor assay detector that uses two ligands is used to obtain effectively the metabolic profile of endogenous receptoractive opioid peptides in the canine pituitary and in seven selected brain regions including the hypothalamus, caudate nucleus, mid‐brain, amygdala, thalamus, pons‐medulla, and the hippocampus. Gradient RP/HPLC separates a mixture of endogenous peptides over a wide range of hydrophobicities. A novel opioid preparation from canine limbic system synaptosomes is utilized in a radioreceptorassay screen; tritiated etorphine (ET) or D‐2ala, D‐5leu‐leucine enkephalin (DADL) is used as the competitively displaced ligand. This receptor‐rich preparation contains several receptor types, and thus serves well as a screen with the required low level of specificity. Subsequent analysis with other detectors of high specificity (MS, RIA) will follow this screen in other studies. Etorphine interacts with several of the opioid peptide‐preferring receptors, whereas DADL is more specific towards the delta receptor that preferentially binds the smaller pentapeptides of the enkephalin family. The highest amount of peptide receptor activity found in this study is in the pituitary tissue, a smaller amount in the hypothalamus and caudate nucleus, and still lower amounts in the other five brain tissue extracts. This variation in peptide concentration most probably reflects three separate factors that operate in this biologic system: differential tissue‐specific processing patterns of the large peptide precursors; distribution of the three opioid peptide systems; and the receptor preparation and the radioligand used in the assay. The structures of the receptoractive compounds in each RP/HPLC peak await mass spectrometric confirmation.
Improved TLC systems for rapid resolution of phenyl thiohydantoin amino acids
Authors: Bhushan R. , Mahesh V. K. , Mallikharjun P. V.
Published: May 2005

Two new solvent systems, n‐hexane + propionic acid (26:5, v/v) and chloroform + acetone (29:3, v/v), for the rapid resolution and identification of an 18‐component mixture of phenylthiohydantoin amino acids are reported. Using these systems certain difficult combinations of phenylthiohydantoin amino acids are resolved. Two more solvent systems, viz chloroform+acetic acid (27:3, v/v) and chloroform + methanol (30:4, v/v), are developed to resolve phenylthiodantoin derivatives of aspartic and glutamic acids.
Determination of bile acids and their conjugates in serum by HPLC using immobilized 3α‐hydroxysteroid dehydrogenase for detection
Authors: Campbell G. R. , Odling‐Smee G. W. , Rowlands B. J. , Irvine G. B.
Published: May 2005

A method is described for the separation of unconjugated bile acids and their glycine and taurine conjugates in a single step with adequate sensitivity for analysis of serum samples. Separation was carried out over a period of 80 min using a linear gradient with increasing concentrations of methanol in aqueous ammonium dihydrogen phosphate buffer, on an ODS Spherisorb column. Spectrofluorometric detection of NADH, formed as the column eluate passed through a column of immobilized 3α‐hydroxysteroid dehydrogenase, enabled amounts less than 40 pmol to be quantified. The reaction was carried out at neutral pH so that the lifetime of the enzyme column was increased, compared to other methods where a pH nearer 9.0 is commonly used. Flow rates were optimized to give comparable peak area for both primary and secondary bile acids.
Determination of urinary 5‐hydroxy‐3‐indoleacetic acid by an automated HPLC method
Authors: Koel Marlies , Nebinger Peter
Published: May 2005

A HPLC method for the quantitative determination of 5‐hydroxy‐3‐indoleacetic acid (5‐HIAA) in urine is described. The method is based on ion‐pair chromatography, reversed phase (RP) column material and specific fluorimetric detection at 300 nm and 355 nm. Sample preparation and gradient elution were avoided by using a column‐switching technique. The sensitivity of the assay was excellent for clinical routine analysis, with a detection limit of 0.2 mg/L 5‐HIAA. No endogenous or exogenous interference problems arose. Intra‐ and interassay precision was good, with observed coefficients of variation of 1.5 to 2.6% and 2.1%, respectively. Recoveries were 93 to 98%. The system described can be used for clinical diagnosis and therapy follow‐up of carcinoid tumors. It has been running for over a year without disturbances and with a minimum of technical attendance.
Determination of estriol and creatinine in urine by high performance liquid chromatography
Authors: Ke Li , Yisheng Yuan
Published: May 2005

A quantitative method for the determination of estriol (E3) and creatinine (C) in random urine by high performance liquid chromatography is described. The mobile phase was a mixed solution of methanol and phosphate buffer (0.025 M, pH 6.5) and the detection wavelength was at 205 nm. The method was simple, rapid and accurate. The OCV for E3 and C using this method were 1.7 – 3.4% and 2.2 – 2.5%, respectively. The RCV for E3 and C were 6.2 – 7.0% and 4.5 – 6.9%, respectively. The recoveries were 87 – 104% for E3 and 98 – 103% for C, respectively. The method has been used for clinical determinations.
Quinidine oxidative metabolism. Identification and biosynthesis of quinidine 10,11‐dihydrodiol stereoisomers
Authors: Leroyer R. , Varoquaux O. , Advenier C. , Pays M.
Published: May 2005

The isocratic reversed phase high performance liquid chromatographic method proposed for quinidine metabolic studies facilitates particularly the separation of 10(R) and (S) isomers of quinidine 10,11‐dihydrodiols. The finding of each of these forms following a new synthetic pathway allows us to identify and quantify them in biological fluids. These two isomers have especially been observed in rat bile and hepatocyte secretions. The metabolic inducing effect of phenobarbital on the oxidative metabolism of quinidine is verified in rat isolated hepatocytes. Simultaneous secretion of the two dihydrodiols is also verified in human urine by a gas chromatography/mass spectrometry procedure.
Qualitative and quantitative high performance liquid chromatographic analysis of monoamine neurotransmitters and metabolites in cerebrospinal fluid and brain tissue using reductive electrochemical detection
Authors: Schmidt Dennis , Roznoski Molly , Ebert Michael H.
Published: May 2005

The application of reductive coulometric electrochemical detection for analysis of the monoamine neurotransmitters norepinephrine, dopamine, and serotonin and their common metabolites in brain and cerebrospinal fluid following separation by isocratic high performance liquid chromatography is described. The high sensitivity and screening capabilities of coulometric electrodes permits the accurate quantitation of as little as 3–5 pg of these compounds in tissue following a simple single step purification procedure. Moreover, comparison of peak height ratios obtained from analysis of authentic reference standards and tissue samples at selected multiple electrode potentials provides a straightforward means for qualitative evaluation of peak identification and purity during analysis of biological samples. The method is comparatively inexpensive and precise within and between day coefficients of variation for most compounds range from 2–5%. Thirty samples can be run in duplicate in a 24 h period.
Isocratic high performance liquid chromatographic analysis of S‐adenosylmethionine and S‐adenosy ihomocysteine in animal tissues: the effect of exposure to nitrous oxide
Authors: Bottiglieri Teodoro
Published: May 2005

A simple isocratic high performance liquid chromatographic method for the simultaneous measurement of S‐adenosylmethionine (SAM) and S‐adenosylhomocysteine (SAH) in animal tissues is described. The direct injection of perchloric acid tissue extracts and rapid resolution of both compounds in a single run reduces any sampling and analytical errors in determining the SAM/SAH ratio, a measure of methylation reactions. The method has been used to determine changes in brain SAM/SAH ratios after exposure of rats to nitrous oxide.
Simultaneous determination of gemfibrozil and its metabolites in plasma and urine by a fully automated high performance liquid chromatographic system
Authors: Nakagawa Akihiko , Shigeta Akemi , Iwabuchi Haruo , Horiguchi Masaaki , Nakamura Kan‐ichi , Takahagi Hidekuni
Published: May 2005

Sensitive and specific methods for the simultaneous determination of gemfibrozil (Lopid®), a lipid‐lowering agent, and its metabolites in plasma and urine are described. The methods are based on a fully automated high performance liquid chromatographic (HPLC) system with fluorescence detection. Urine samples, diluted with acetonitrile, were directly analysed by HPLC using a flow and eluent programming method. In the case of plasma, gemfibrozil and its main metabolites were extracted from acidified samples and the resulting extracts injected into the chromatographic system. The sensitivity was approximately 100 ng/mL for gemfibrozil and its four metabolites using 0.5 mL plasma or urine. An acyl glucuronide of gemfibrozil excreted in human urine after oral administration of the drug was isolated and its structure and stability examined.
High performance liquid chromatography with chemiluminescence detection of methamphetamine and its related compounds using 4‐(N,N‐dimethylaminosulphonyl)‐7‐fluoro‐2,1,3‐benzoxadiazole
Authors: Nakashima Kenichiro , Suetsugu Keiko , Yoshida Kazunori , Akiyama Shuzo , Uzu Sonoko , Imai Kazuhiro
Published: May 2005

A high performance liquid chromatographic assay of methamphetamine (MP) and its related compounds, i.e. ephedrine (EP), norephedrine (NE), p‐hydroxymethamphetamine (p‐HMP), p‐hydroxyamphetamine (p‐HAP) and amphetamine (AP), with peroxyoxalate chemiluminescence detection has been developed. 4‐(N,N‐Dimethylaminosulphonyl)‐7‐fluoro‐2,1,3‐benzoxadiazole (DBD‐F) was used as a fluorescent labelling reagent. A mixture of hydrogen peroxide and bis[4‐nitro‐2(3,6,9‐trioxadecyloxycarbonyl)phenyl] oxalate in acetonitrile was used as a postcolumn chemiluminogenic reagent. DBD derivatives of MP and its related compounds were separated by a gradient elution with acetonitrile and 0.01 M imidazole buffer (pH 7.0) within 65 min. The detection limits (S/N = 3) for the proposed method for MP, AP, EP, NE, p‐HMP and p‐HAP were 27, 100, 40, 133, 25 and 133 fmol on column, respectively. The recoveries of these compounds with normal urine samples were 87.4–106.4%. The method was successfully applied to the assay of MP and its metabolites in urine samples from MP addicts. A good linear correlation for the resulted amounts of MP or AP between the proposed method and gas chromatography was obtained (r = 0.993 for MP or 0.991 for AP).
Simple determination of hydrochlorothiazide in human plasma and urine by high performance liquid chromatography
Authors: de Vries J. X. , Voss A.
Published: May 2005

The diuretic drug hydrochlorothiazide (HCT) is used mainly for treatment of mild to moderate hypertension and is usually administered with other drugs. An assay for the determination of HCT in human plasma and urine by high performance liquid chromatography (HPLC) has been developed. Samples were purified by solvent extraction and analysed by reversed phase HPLC with ultraviolet detection, using hydroflumethiazide as the internal standard; plasma was eluted using gradient elution and urine was analysed isocratically. The method is simple to perform, is sensitive (detection limit 0.01 μg/mL in plasma and 0.2 μg/mL for urine); it showed good reproducibility (3–8%). A great number of drugs did not interfere with the assay and the method was used for pharmacokinetic studies in healthy subjects, but samples from patients can also be analysed with high selectivity.
Study of chemobiological reactions. 1. Selectivity of aromatic amino compounds and saccharides in glycosylation reactions
Authors: Kinoshita Toshio , Miyayama Miyoko , Kyodo Yukiko , Kamitani Yoshie , Miyamasu Misato , Nimura Noriyuki , Hanai Toshihiko
Published: May 2005

The reactivities between saccharides and primary amino compounds were studied by liquid chromatography on an amino‐bonded column and by measurement of the reaction rates of aromatic amines with saccharides. The recoveries from the column and the reaction rates were correlated with their physicochemical properties calculated by the CACheTM program. The reactivities between amines and saccharides correlated well with their hydrogen bonding energies calculated by molecular mechanics.
Simultaneous determination of NK611, a novel water‐soluble derivative of etoposide, and its metabolite (DeNK611) in dog plasma by column‐switching high performance liquid chromatography
Authors: Machida Megumi , Tanaka Shigeo , Nakamori Kota
Published: May 2005

A simple, selective, reversed phase liquid chromatographic method using a column‐switching technique has been developed for the simultaneous determination of a novel derivative of etoposide (NK611) and its O‐demethyl metabolite in dog plasma. A good linear response was obtained for both drugs in the range 0.1‐12.0 μg/mL. The mean recoveries were within 100±5%. The within‐ and between‐day precisions were within 3.5% and 4.6%, respectively. This method was used in a pharmacokinetic study following intravenous and oral administration of NK611 to beagle dogs.
Thin‐layer chromatographic determination of brain catecholamines and 5‐hydroxytryptamine
Authors: Alemany G. , Nicolau M. C. , Gamundí A. , Rial R.
Published: May 2005

A simple and sensitive (up to nanogram level) method to determine norepinephrine, serotonine and dopamine in rat brain is described. The amines are acetyled and the derivatives are resolved by thin layer chromatography (TLC) on silica high performance thin layer chromatography (HPLC) plates. Quantification is achieved by fluorescence densitometry at 415 nm excitation wavelength.
Direct enantioselective separation of bevantolol by high‐performance liquid chromatography on normal and reverse cellulose chiral stationary phases
Authors: Aboul‐Enein Hassan Y. , Serignese Vince
Published: May 2005

A direct, isocratic and simple chromatographic method is described for the enantiomeric separation of bevantolol (BEV) using normal and reverse cellulose tris (3,5‐dimethylphenylcarbamate) chiral stationary phases (CSPs) known as Chiralcel OD and Chiralcel OD‐R, respectively. The effect of various alcohols present in the mobile phase on the separation factor (α) and resolution factor (Rs) has been studied.

The method has been used to determine and identify the BEV enantiomers in human urine after oral administration of racemic BEV. The chiral recognition mechanism(s) between the analyte and these chiral stationary phases is proposed.
High performance liquid chromatographic determination of methacrylate in blood serum
Authors: Bereznowski Zdzislaw , Marlewski Maciej , Smolenski Ryszard T.
Published: May 2005

Methacrylic acid is a hydrolytic breakdown product of methylmethacrylate which is widely used in orthopaedic surgery, dentistry and in the chemical industry for fabrication of acrylic resins. Information on the toxicity of methacrylic acid and its metabolism is limited. To facilitate studies in this field we developed a liquid chromatographic procedure allowing determination of methacrylate in blood serum. The procedure was based on reversed‐phase HPLC using a gradient elution with UV detection at 210 or 240 nm. The method was linear up to 5 mM concentration with a detection limit of 0.5 μM. The procedure was applied to determination of methacrylate in rat blood serum after administration of sodium methacrylate solution into the stomach. A peak of this compound was demonstrated in the chromatogram 10 min after administration which disappeared after 60 min, confirming suitability of the method for biological applications.
Studies on standardization of folium strobilanthis, radix strobilanthis and their preparations
Authors: Ling Li , Tong‐Yi Dong , Xiu‐Lu Li , Chuan‐Zhuo Qiao
Published: May 2005

Determination of 4(3H)‐quinazolinone, a newly found antiviral and immunopatentiating constituent was proposed as a method of evaluating the quality of two antiviral Chinese herbal drugs Daqingye (Folium Strobilanthis) and Banlangen(Radix Strobilanthis) and their preparations (‘Antipyretic and common cold granules’, ‘Banlangen granules’). An HPLC method for determining the content of 4(3H)‐quinazolinone was established with satisfactory results. The method showed good linearity (r = 0.9998, n = 5) in the range of 0.25–50 μg/mL of 4(3H)‐quinazolinone, the average recovery was above 99% with RSD < 0.78% (n = 3).
Immunoaffinity capillary electrophoretic analysis of cyclosporin in tears
Authors: Phillips Terry M. , Chmielinska Joanna J.
Published: May 2005

An immunoaffinity capillary electrophoresis technique has been developed for the analysis of cyclosporin A in human tear fluid following topical application of the drug. The technique combines the selectivity of immunoaffinity separation with the high‐resolution of capillary electrophoresis by immobilizing monoclonal antibody fragments directly onto the internal surface of the capillary. This technique was used to measure cyclosporin levels in tears obtained from corneal transplant patients during normal and drug toxicity episodes in the course of their treatment. Comparison of this technique with HPLC detection of cyclosporin in tears showed a good correlation, with the immunoaffinity CE technique having the advantage of being able to simultaneously detect toxic metabolites of cyclosporin in the same sample.
Direct determination of free phenylacetic acid in human plasma and urine by column‐switching high performance liquid chromatography with flurescence detection
Authors: Iwata Tetsuharu , Ishimaru Takayuki , Nakamura Masaru , Yamaguchi Masatoshi
Published: May 2005

A simple and highly sensitive column‐switching high performance liquid chromatographyic method with fluorescence detection for the determination of free phenylacetic acid (PAA) in human plasma and urine is described. The method is based on the direct derivatization of plasma and urine PAA with 6,7‐dimethoxy‐1‐methyl‐2(1H)‐quinoxalinone‐3‐propionylcarboxylic acid hydrazide (DMEQ‐hydrazide). The derivatization reaction proceeds in aqueous solution in the presence of pyridine and 1‐ethyl‐3‐(3‐dimethylaminopropyl)‐carbodiimide at 37°C. The resulting DMEQ derivative of PAA is separated from endogenous interfering substances by a column‐switching chromatographic system consisting of a precolumn (YMC‐Pack C4) for sample clean‐up and an analytical column (L‐Column ODS) for the complete separation of the derivative. The derivative is detected fluorimetrically at 445 nm wih excitation at 367 nm. The detection limits (signal to noise ratio = 3) for PAA is 10 fmol in a 10 μL injection volume. The recoveries from plasma and urine are 75 and 96%, respectively. The present method is highly sensitive and simple compared to conventional liquid‐liquid extraction procedures. The sensivity allows the direct determination of free PAA in an extremely small amount (5 μL) of plasma and urine.
Determination of glutathione in biological samples by high performance liquid chromatography with fluorescence detection
Authors: Gotti Roberto , Andrisano Vincenza , Gatti Rita , Cavrini Vanni , Candeletti Sanzio
Published: May 2005

A selective and sensitive high performance liquid chromatographic (HPLC) method has been developed for the determination of reduced glutathione (GSH) in biological samples (rat liver, spleen and plasma). The method involved a prechromatographic thiol derivatization with methyl 4‐(6‐methoxynaphthalen‐2‐yl)‐4‐oxo‐2‐butenoate; the reaction was rapid (5 min) under mild conditions (pH 7.5 and ambient temperature) and selective for the sulphydryl group. The thiol adducts were separated on a reversed‐phase C‐18 column using acetonitrile: 0.05 M triethylammonium (TEA) phosphate (pH 4) solution 32:68 (v/v) as the mobile phase. Fluorescence detection (λem = 450 nm; λexc = 310 nm) was used and the detection limit (S/N = 3) was about 0.5 pmole of the injected GSH adduct. The method was also applied to the determination of total glutathione in rat plasma after a preliminary reduction with dithiothreitol.
Direct separation of tranylcypromine enantiomers and their profile in an atypical depressive patient
Authors: Aboul‐Enein Hassan Y. , Serignese Vince
Published: May 2005

An isocratic and simple high‐performance liquid chromatographic method is developed for the diirect resolution of the tranylcypromine (TCP) enatiomers. The method involves the use of an S‐18‐crown‐6‐ether chiral stationary phase known as the Crownpak CR (+) column. The stereochemical separation factor (α) obtained was 1.30 and the stereochemical resolution factor (Rs) was 0.69 when using a mobile phase consisting of 0.1 N perchloric acid containing 12% methanol at 23°C. The method has been used to monitor and identify, qualitatively, the profile of enantiomers of TCP in urine of an atypical depressive patient. It was found that the (−)‐S‐TCP concentration is significantly higher than the (+)‐R‐enantiomer.
Enzyme analysis and subcellular fractionation of human peripheral blood lymphocytes with special reference to the localization of putative plasma membrane enzymes
Authors: Shah Tarulata , Webster A. D. B. , Peters Timothy J.
Published: May 2005

Human lymphocytes were isolated from defibrinated blood by Ficoll‐Hypaque centrifugation with erythrocyte hypotonic lysis. Homogenates of mixed lymphocytes were subjected to analytical subcellular fractionation by sucrose gradient centrifugation in a Beaufay automatic zonal rotor. The principal organelles were characterized by their marker enzymes: cytosol (lactate dehydrogenase), plasma membrane (5′‐nucleotidase), endoplasmic reticulum (neutral α‐glucosidase), mitochondria (malate dehydrogenase), lysosomes (N‐acetyl‐β‐glucosaminidase), peroxisomes (catalase). γ‐Glutamyl transferase was exclusively localized to the plasma membrane. Leucine amino‐peptidase, especially when assayed in the presence of Co2+, was also partially localized to the plasma membrane. Experiments with diazotized sulphanilic acid, a non‐permeant enzyme inhibitor, showed that these plasma membrane enzymes are present on the cell surface. No detectable alkaline phosphatase was found in the lymphocytes. Acid phosphatase and β‐glucuronidase were localized to lysosomes and there was some evidence for lysosomal heterogeneity. Leucine amino peptidase, optimal at pH 8.0, showed a partial localization to intracellular vesicles, possibly lysosomes, especially when assayed in the presence of EDTA. These studies provide a technique for determining the intracellular distribution of hitherto unassigned lymphocyte constituents and serve as a basis for investigating the cell pathology of lymphocytic disorders.
Thiols and pancreatic β‐cell function: A review
Authors: Ammon H. P. T. , Mark M.
Published: May 2005

In pancreatic islets insulin secretion in response to a variety of stimulators is sensitive to the redox state of extracellular and intracellular thiols. In this connection variations of plasma glutathione (GSH) may also be of importance. In the process of stimulus‐secretion coupling, membrane thiols play an important role. One major localization of critical thiols appears to be related to the influx of calcium through the voltage‐dependent channel.

Other transmembranal ion movements and the cAMP system seem to be less sensitive to thiol oxidation than calcium influx via voltage‐dependent Ca channels.
Rat hypothalamic extract inhibits vasopressin‐stimulated Na+‐K+‐ATPase activity in the rat renal medulla
Authors: Pippard Corinna , Baylis P. H.
Published: May 2005

Arginine vasopressin stimulates Na+‐K+‐ATPase activity located in the rat thick ascending limb of s'Henle loop. Mammalian hypothalamus appears to produce a factor capable of inhibiting Na+‐K+‐ATPase activity in a variety of tissues. The effect of a purified rat hypothalamic extract with and without AVP on rat renal Na+‐K+‐ATPase activity was evaluated by a cytochemical technique. The hypothalamic extract alone failed to affect basal Na+‐K+‐ATPase activity throughout renal segments after 10 min exposure. Na+‐K+‐ATPase activity stimulated by AVP (1–10 fmol l−1) for 10 min was inhibited by rat hypothalamic extract over the concentration range 10−7–10−3 U ml−1 in a dose‐dependent manner. Complete inhibition of AVP‐stimulated Na+‐K+‐ATPase activity occurred at a hypothalamic extract concentration of 10−3 U ml−1. Only Na+‐K+‐ATPase activity located in the renal medullary thick ascending limb was influenced by the rat hypothalamic extract.
A polyclonal antiserum against the rabbit progesterone receptor recognizes the human receptor: Biochemical characterization
Authors: Feil Peter D. , Clarke Christine L. , Satyaswaroop Pondichery G.
Published: May 2005

Polyclonal antiserum was generated in guinea pigs immunized with the 116 000 Mr rabbit uterine progesterone receptor (PR). The PR antigen was partially purified by DEAE‐cellulose chromatography and preparative sodium dodecyl sulphate–polyacrylamide gel electrophoresis, transferred to nitrocellulose, and the 116 000 Mr band excised and injected into guinea pigs. The antiserum recognized on protein blots rabbit uterine PR of Mr 116 000 and 81 000. The antiserum was judged to be specific for PR from normal and malignant human tissues as determined by sedimentation shift on sucrose gradients, immunoprecipitation studies, protein blotting, and fluorographic analysis using photolabelled samples. Comparison of protein blots probed with this polyclonal antiserum or with a recently obtained monoclonal antibody to human PR indicated that similar PR structures were recognized in rabbit and human samples by both antisera. Characterization of the polyclonal antiserum has demonstrated its suitability for investigating the immunolocalization or PR in normal and malignant human tissues as well as the receptor structure detected on protein blots.
Chromatin organization in rat testis nuclei. Flow cytometric detection of the morphological compaction
Authors: Papa S. , Vitale M. , Rizzoli N. , Zini N. , Matteucci A. , Cecchini T. , Maraldi N. M.
Published: May 2005

The unusual histone composition of testicular cells generates changes in chromatin organization in order to allow the chromosomal pairing necessary for genetic recombination. Accessibility of testis nuclear DNA was determined by flow cytometry. The observed differences in staining between testis and liver nuclear chrmatin, as well as the differences of perpendicular light scatter signal, correlated with alterations in protein composition with the chromatin reorganization.
Susceptibility of Gamma‐Irradiated Proteins to In Vitro Glycation: Exposure to Oxygen Free Radicals Increases Glycation‐Induced Modifications
Authors: Traverso Nicola , Odetti Patrizio , Cheeseman Kevin , Cottalasso Damiano , Marinari Umberto Maria , Pronzato Maria Adelaide
Published: May 2005

Oxidation and glycation are non‐enzymatic protein modifications involved in the pathogenesis of aging. We evaluated their possible influences in an in vitro system: albumin was oxidized by gamma‐irradiation and then exposed to glycation in vitro. Fluorescence modifications were analysed as signals of protein alterations. Both radiolytic oxidation and in vitro glycation provoked a sharp decrease of tryptophan fluorescence (278 nm ex./340 nm em.); their effects tended to be additive, unless a saturation limit was reached. Both individually and in combination, these two non‐enzymatic processes induced the appearance of a new fluorescence (335 nm ex./415 nm em.); in this case as well there was an additive effect, with a trend toward saturation. Radiolytic oxidation and in vitro glycation seem to provoke similar damage to the exposed proteins: the observed fluorescence alterations may be due to similar conformational changes, breaks or the development of fluorophores.
The Taguchi influence on designed experiments
Authors: Stone R. A. , Veevers A.
Published: May 2005

This paper is intended to convey the essence of Taguchi's design approach to chemists and others with an interest in chemometrics. Although most Taguchi‐style applications worldwide have been in electronics and in elaborately transformed manufactures, examples are increasingly found in chemical processes and in the food industry.

Foremost among Taguchi's contributions is the concept of designing processes and products to be robust to the uncontrollable environmental influences which they experience during their operation or lifetime. This concept is explained with a worked example.
ZnII–Salphen Complexes as Versatile Building Blocks for the Construction of Supramolecular Box Assemblies
Authors: Kleij Arjan W. , Kuil M. , Tooke Duncan M. , Lutz Martin , Spek Anthony L. , Reek Joost N. H.
Published: May 2005

ZnII–salphen complexes are readily accessible and interesting supramolecular building blocks with a large structural diversity. Higher‐order supramolecular assemblies, such as molecular boxes based on a bis‐ZnII–salphen building block and various ditopic bipyridine ligands, have been constructed by means of supramolecular, coordinative ZnII–Npyr interactions. The use of bipyridine ligands of differing sizes enables the construction of structures with predefined box diameters. The features of the 2:2 box assemblies were investigated in detail by (variable temperature) NMR spectroscopy, UV‐visible spectroscopy, NMR titrations, and X‐ray crystallographic studies. The spectroscopic studies reveal a high association constant for the ZnII–salphen–pyridyl motif, which lies in the range 105–106 M−1. The strong interaction between the ZnII center and pyridine donors was supported by PM3 calculations that showed a relatively high Lewis acid character of the metal center in the salphen complex. Titration curves monitored by UV‐visible show a cooperative effect between the two bipyridine ligands upon complexation to the bis‐ZnII template, suggesting the formation of 2:2 complexes. The crystal structures of two supramolecular boxes have been determined. In both examples such a 2:2 assembly is present in the solid state, and the box size is different because they consist of different building blocks. Interestingly, the box assemblies line up in the solid state to form porous channels that are potentially useful in a number of applications.
Synthesis and Characterization of Amorphous Hydrated Alkali Thio‐Hydroxogermanates.
Authors: Poling Steven A. , Nelson Carly R. , Martin Steve W.
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
Synthesis and Crystal Structure of Bis(tetraethylammonium) Octabromo‐triselenate(II)‐{dibromodiselenate(I)}, [NEt4]2 [Se3Br8(Se2Br2)], the Salt of a Mixed‐Valence Bromoselenate(II,I) Anion.
Authors: Janickis Vitalijus , Milius Wolfgang , Toernroos Karl Wilhelm
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
The Satellite‐Shaped Co‐15 Polyoxotungstate, [Co6(H2O)30{Co9Cl2 (OH)3(H2O)9 (β‐SiW8O31)3}]5‐.
Authors: Bassil Bassem S. , Nellutla Saritha , Kortz Ulrich , Stowe Ashley C. , van Tol Johan , Dalal Naresh S. , Keita Bineta , Nadjo Louis
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
Development of Electrochemical Processes for Nitrene Generation and Transfer.
Authors: Siu Tung , Picard Christine J. , Yudin Andrei K.
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
Diastereoselective Addition of Organolithiums to 1,3‐Oxazolidines Complexed with Aluminum Tris(2,6‐diphenylphenoxide) (ATPH).
Authors: Yamauchi Takayasu , Sazanami Hiroyuki , Sasaki Yuuichi , Higashiyama Kimio
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
Unusual and Unexpected Reactivity of t‐Butyl Dicarbonate (Boc2O) with Alcohols in the Presence of Magnesium Perchlorate. A New and General Route to t‐Butyl Ethers.
Authors: Bartoli Giuseppe , Bosco Marcella , Locatelli Manuela , Marcantoni Enrico , Melchiorre Paolo , Sambri Letizia
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
The Regioselective Synthesis of Monomethoxynaphthylene Diacetates.
Authors: Maiti Bhim C. , Musgrave Oliver C. , Skoyles Douglas
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
A Facile Tandem Radical Cyclization Route to Propellanes and Its Application to a Total Synthesis of Modhephene.
Authors: Lee Hee‐Yoon , Moon Deuk Kyu , Bahn Jong Soo
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
Mechanism and Scope of the Cyanide‐Catalyzed Cross Silyl Benzoin Reaction.
Authors: Linghu Xin , Bausch Cory C. , Johnson Jeffrey S.
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
Homologation of Vicinal Polyketone Networks to Epoxy Ketones with Diazomethane.
Authors: Hartung Ryan E. , Paquette Leo A.
Published: May 2005

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Combinatorial Chemical Synthesis of 4‐Heteroaryl‐3‐Substituted Pyrroles from Nitroalkenes.
Authors: Baldoli Clara , Cremonesi Giuseppe , Dalla Croce Piero , La Rosa Concetta , Licandro Emanuela
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
Synthesis and Evaluation of Novel Peripherally Restricted ϰ‐Opioid Receptor Agonists.
Authors: Kumar Virendra , et al. et al.
Published: May 2005

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Five‐Membered 2,3‐Dioxo Heterocycles. Part 49. Reaction of Methyl 1‐Aryl‐3‐aroyl‐4,5‐dioxo‐4,5‐dihydro‐1H‐pyrrole‐2‐carboxylates with N‐Substituted 3‐Amino‐5,5‐dimethyl‐2‐cyclohexenones.
Authors: Bannikova Yu. N. , Maslivets A. N. , Aliev Z. G.
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
A Modular, One‐Pot, Four‐Component Synthesis of Polysubstituted 1,3‐Oxazolidines.
Authors: Tejedor David , Santos‐Exposito Alicia , Gonzalez‐Cruz David , Marrero‐Tellado Jose Juan , Garcia‐Tellado Fernando
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
A New Bactericidal Lead Structure for the Protection of Materials.
Authors: Vogl Erasmus , Bruns Rainer , Kretschik Oliver , Uhr Hermann , Kaulen Johannes , Kugler Martin , Wachtler Peter , Kreiss Wolfgang , Eberz Guenther
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
Synthesis and SAR of 5,6‐Diarylpyridines as Human CB1 Inverse Agonists.
Authors: Meurer Laura C. , et al. et al.
Published: May 2005

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Functionalization at Position 3 of the Phenyl Ring of the Potent mGluR5 Noncompetitive Antagonists MPEP.
Authors: Alagille David , Baldwin Ronald M. , Roth Bryan L. , Wroblewski Jarda T. , Grajkowska Ewa , Tamagnan Gilles D.
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
Discovery and Structure—Activity Relationships of Novel Selective Norepinephrine and Dual Serotonin/Norepinephrine Reuptake Inhibitors.
Authors: Walter Magnus W. , et al. et al.
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
3,4‐Dihydro‐2H‐benzoxazinones are 5‐HT1A Receptor Antagonists with Potent 5‐HT Reuptake Inhibitory Activity.
Authors: Johnson Christopher N. , et al. et al.
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
P‐Chiral Phosphinoselenoic Chlorides and Phosphinochalcogenoselenoic Acid Esters: Synthesis, Characterization, and Conformational Studies.
Authors: Kimura Tsutomu , Murai Toshiaki
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
Podospermic Acid, 1,3,5‐Tri‐O‐(7,8‐dihydrocaffeoyl)quinic Acid from Podospermum laciniatum (Asteraceae)
Authors: Zidorn Christian , Petersen Bent O. , Udovicic Vedrana , Larsen Thomas O. , Duus Jens O. , Rollinger Judith M. , Ongania Karl‐Hans , Ellmerer Ernst P. , Stuppner Hermann
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
Synthesis of Modified Proanthocyanidins: Easy and General Introduction of a Hydroxy Group at C‐6 of Catechin; Efficient Synthesis of Elephantorrhizol.
Authors: Boyer Francois‐Didier , Es‐Safi Nour‐Eddine , Beauhaire Josiane , Le Guerneve Christine , Ducrot Paul‐Henri
Published: May 2005

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Radical Oxidative Cyclization of Spiroacetals to Bis‐spiroacetals
Authors: Brimble Margaret A.
Published: May 2005

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Ketone Hydrogenation Technology
Authors: Zanotti‐Gerosa Antonio , Groarke Michelle , Hems William P.
Published: May 2005

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Evolving Cascades: The Claisen Rearrangement in the Development of Tandem Sequences of Three or More Reactions
Authors: Gray Brian Lawrence , Ley Steven V.
Published: May 2005

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Eco‐Efficiency — A Challenge for Process Development
Authors: Buerli Martin
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
The Optical Spectroscopy of Extraterrestrial Molecules
Authors: Schmidt Timothy W. , Sharp Robert G.
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
In vivo EPR: When, How and Why?
Authors: Gallez Bernard , Swartz Harold M.
Published: May 2005

For Abstract see ChemInform Abstract in Full Text.
Characterization of Amoeba proteus myosin VI immunoanalog
Authors: Dominik Magdalena , Kłopocka Wanda , Pomorski Paweł , Kocik Elżbieta , Rędowicz Maria Jolanta
Published: May 2005

Amoeba proteus, the highly motile free‐living unicellular organism, has been widely used as a model to study cell motility. However, molecular mechanisms underlying its unique locomotion and intracellular actin‐based‐only trafficking remain poorly understood. A search for myosin motors responsible for vesicular transport in these giant cells resulted in detection of 130‐kDa protein interacting with several polyclonal antibodies against different tail regions of human and chicken myosin VI. This protein was binding to actin in the ATP‐dependent manner, and immunoprecipitated with anti‐myosin VI antibodies. In order to characterize its possible functions in vivo, its cellular distribution and colocalization with actin filaments and dynamin II during migration and pinocytosis were examined. In migrating amoebae, myosin VI immunoanalog localized to vesicular structures, particularly within the perinuclear and sub‐plasma membrane areas, and colocalized with dynamin II immunoanalog and actin filaments. The colocalization was even more evident in pinocytotic cells as proteins concentrated within pinocytotic pseudopodia. Moreover, dynamin II and myosin VI immunoanalogs cosedimented with actin filaments, and were found on the same isolated vesicles. Blocking endogenous myosin VI immunoanalog with anti‐myosin VI antibodies inhibited the rate of pseudopodia protrusion (about 19% decrease) and uroidal retraction (about 28% decrease) but did not affect cell morphology and the manner of cell migration. Treatment with anti‐human dynamin II antibodies led to changes in directionality of amebae migration and affected the rate of only uroidal translocation (about 30% inhibition). These results indicate that myosin VI immunoanalog is expressed in protist Amoeba proteus and may be involved in vesicle translocation and cell locomotion. Cell Motil. Cytoskeleton 61:172–188, 2005. © 2005 Wiley‐Liss, Inc.