bluuebunny/crossref_metadata_2025_split huggingface dataset:
A sensitive high performance liquid chromatography microassay for bemoradan, a novel cardiotonic agent, in plasma/serum using a semi‐automatic liquid/solid extraction sample preparation system—AASP®
Authors: Huang Shiew‐Mei , Chien Shu‐Chean , Flor Soledad C. 
Published: May 2005

AbstractA high performance liquid chromatographic method for the measurement of bemoradan levels in plasma/serum is described. This method uses Varian's AASP® (Varian Associates, Sunnyvale, CA, USA), a semi‐automatic liquid/solid extraction sample preparation system. It requires only small volumes of plasma/serum samples (0.2–1 mL) and needs no organic solvent for sample preparation. The mean recovery of bemoradan at plasma or serum concentrations of 0.5–100 ng/mL is 82%. The assay has a detection limit of 0.5 ng/mL (when 1 mL of plasma/serum is used) and is linear in the concentration range 0.5–500 ng/mL.
Determination of polyamines in urine of normal human and cancer patients by capillary gas chromatography
Authors: Jiang Xiaochun 
Published: May 2005

AbstractA capillary gas chromatographic method is described for the determination of polyamines (putrescine, spermidine and spermine) in the urine of normal human and cancer patients. Morning urine after acid hydrolysis is cleaned up on a silica gel column and derivatized with trifluoroacetic‐anhydride. Creatinine in human urine is used as internal standard. Recoveries of polyamines are 96.7% putrescine, 102.6% spermidine (Spd), and 98.7% spermine. SD of the method for Spd is 1.949 ± 0.041 (μg/mg creatinine, mean ±SD, n = 5). The results show that the mean level of polyamines in cancer patients urine is much higher than that in normal human urine. The mean of total polyamines in the normal human and the cancer patients is 2.01 and 44.74, respectively (g/mg creatinine).
A simple, sensitive liquid chromatographic method for quantitation of D‐galactose and D‐glucose in blood plasma
Authors: Griffin Brenda W. , Williams Gary W. 
Published: May 2005

AbstractThe concentrations of D‐glucose and D‐galactose in plasma of galactosemic rats were quantitatively measured by a liquid chromatographic method, based on retention of the weakly ionized monosaccharides by an anion exchange column under alkaline conditions, elution with 9 mmol/L NaOH, and electrochemical detection. This method is both simple and sensitive, since very dilute plasma samples can be directly analysed.
Determination of lipid hydroperoxides in low density lipoprotein from human plasma using high performance liquid chromatography with chemiluminescence detection
Authors: Miyazawa Teruo , Fujimoto Kenshiro , Oikawa Shin‐Ichi 
Published: May 2005

AbstractA high performance liquid chromatographic system with chemiluminescence detection (HPLC‐CL) was used for determining phospholipid hydroperoxides in human plasma low density lipoprotein (LDL). This system involved separation of phospholipids from LDL‐total lipids with normal phase silica gel HPLC and post‐column detection of hydroperoxide‐dependent chemiluminescence produced by luminol oxidation during the reaction of hydroperoxide with cytochrome c‐haeme. By using HPLC‐CL, we could detect phosphatidylcholine hydroperoxide (PCOOH) in human plasma LDL, and the LDL‐PCOOH concentration was significantly higher in patients with atherosclerosis and hyperlipidemia than that of healthy volunteers. The LDL‐PCOOH level was proportional to the plasma total cholesterol concentration.
Separation of the Hageman factor fragment from human serum albumin by chromatography on Blue Sepharose CL‐6B
Authors: Simonianová E. , Hrkal Z. 
Published: May 2005

AbstractThe separation of the Hageman factor fragment (HFf) activity from human serum albumin by chromatography on Blue Sepharose CL‐6B is described. The complete separation cannot be achieved in a single chromatography step due to complex formation between HFf and albumin.
Analysis of lorazepam in rat brain using liquid/liquid and solid‐phase extraction in combination with high performance liquid chromatography
Authors: Gunawan S. , Walton N. Y. , Treiman D. M. 
Published: May 2005

AbstractA method for the determination of lorazepam in rat brain is described using liquid/liquid and solid‐phase extraction, followed by high performance liquid chromatography. After addition of chlordiazepoxide as the internal standard, 100 mg brain tissue was homogenized and incubated with alkaline protease. Lorazepam and chlordiazepoxide were extracted three times with toluene. After treatment through a C 18‐Bond Elut column, lorazepam and chlordiazepoxide were analyzed isocratically on a reversed‐phase column with a mobile phase consisting of methanol + 0.025 M sodium phosphate buffer (66:34, v/v). The eluted drugs were monitored by their absorption at 240 nm. The sensitivity limit of this method was 10 ng of lorazepam per 100 mg of brain tissue sample. The standard curve was linear over the range of 20 to 200 ng lorazepam. The coefficient of variation for day‐to‐day precision established by 21 replicate analyses was 4.5 to 13.6%.
Determination of lipoperoxide in animal tissue by ion‐pair reversed phase high performance liquid chromatography
Authors: Li Ke 
Published: May 2005

AbstractAn ion‐pair reversed phase high performance liquid chromatographic method was developed for the quantitative determination of lipoperoxide (as malondialdehyde, MDA) in animal tissue using a ODS column and a mobile phase of methanol + phosphate buffer (53:47 v/v, pH 6.5). Tetrabutylammonium bromide was used as an ion‐pair reagent and the detection wavelength was set at 532 nm.The method was sensitive, accurate and simple. A linear relationship was obtained between the peak height and the amount of MDA from 50 nmol/L to 1200 nmol/L and the lower limit of detection of MDA was 15 nmol/L (signal‐to‐noise ratio > 2), and the coefficient of variation at the 200 nmol/L level was 3.7% (n = 7). The results correlated well with those from the 2‐thiobarbituric acid colorimetric method. The method has been used in the pathogenic studies of cerebral ischemia and acute renal failure for the determination of trace lipoperoxide.
A simple and rapid method for the purification of cytochrome P‐450 (form LM4)
Authors: Alterman Michael A. , Dowgii Andrew I. 
Published: May 2005

AbstractA one step chromatographic method for the purification of membrane protein cytochrome P‐450 LM4 has been developed and it indicates that CM Sepharose Fast‐Flow is an excellent material for cytochrome P‐450 LM4 chromatography.
Use of enzymatic reactors in the high performance liquid chromatographic determination of ethanol and methanol with electrochemical detection
Authors: Tagliaro F. , De Leo D. , Marigo M. , Dorizzi R. , Schiavon G. 
Published: May 2005

AbstractDespite numerous applications both in industry and in analytical chemistry, immobilized enzyme technology has encountered only limited success in modern liquid chromatography. The strict requirements of enzymatic reactors for high performance liquid chromatography (HPLC) (i.e., mechanical resistance, limited void volumes, high contact surface, high binding capacity, stable enzyme‐to‐matrix bond without loss of enzyme activity) are not yet fully met by commercially available products. In our laboratory, the development of post‐column reactors with immobilized alcohol oxidase on‐line with an HPLC/EC system has been undertaken. Three home‐made reactors were produced: in the first alcohol oxidase from Candida boidinii was quasi‐immobilized onto an HPLC‐sized anion exchange support, in the second the enzyme was bound to a silica‐based support via Schiff's base formation, and in the third a covalent linkage to an epoxy‐activated hydroxyalkyl methacrylate material was chosen. Chemical immobilization proved superior to the ionic binding. The importance of limiting the post‐column band spreading due to the reactor void volume, by using HPLC‐sized supports, was confirmed.
L‐dopa as Substrate for human duodenal catechol‐O‐methyltransferase and aromatic L‐amino acid decarboxylase
Authors: Schultz Eija 
Published: May 2005

AbstractCatechol‐O‐methyltransferase (COMT) and aromatic L‐amino acid decarboxylase (AADC) activities were determined in human gastrointestinal samples. L‐dopa was used as the substrate and the reaction products 3‐O‐methyldopa (3OMD) and dopamine were separated by reversed phase HPLC and detected by electrochemical or UV detection. COMT activities varied between 40–350 pmol/mg/min and AADC activities between 100 – 3300 pmol/mg/min in different parts of the gastrointestinal tract. COMT inhibitors nitecapone (OR‐462) and OR‐611 effectively inhibited human gastrointestinal COMT activity in vitro, the IC50 values ranging from 10–20 nM and 5–75 nM, respectively. In vitro carbidopa inhibited AADC slightly more effectively than benserazide.
Coproporphyrinogen oxidase, protoporphyrinogen oxidase and ferrochelatase activities in iron‐overloaded and ethanol‐treated rats
Authors: Li Famei , Lim C. K. , Peters T. J. 
Published: May 2005

AbstractThe activities of coproporphyrinogen oxidase, protoporphyrinogen oxidase and ferrochelatase in liver homogenates of iron‐overloaded and acutely or chronically ethanol‐treated rats were assayed by high performance liquid chromatographic methods. Decreased coproporphyrinogen oxidase activity was found in chronically carbonyliron‐fed rats while the activities of protoporphyrinogen oxidase and ferrochelatase remained unchanged. Coproporphyrinogen oxidase and protoporphyrinogen oxidase activities in both chronically and actuely ethanol‐treated animals were not significantly different from controls. In chronically ethanol‐fed rats normal ferrochelatase activity was found.
The high performance liquid chromatography of enzyme systems relating to purine and pyrimidine metabolism: an overview
Authors: Perrett David , Simmonds H. Anne 
Published: May 2005

AbstractPurines and pyrimidines are now routinely separated by HPLC. By careful selection of chromatographic conditions which match the expected changes in hydrophobicity and/or ionic nature of the substrate and products most enzymes of the purine and pyrimidine salvage pathways can be routinely and accurately determined. Ion‐paired reversed‐phase systems are often the most advantageous. The relevance of such assays to biomedical analysis including their role in the diagnosis of inborn errors of metabolism is stressed.
A new method for the determination of adenine phosphoribosyltransferase activity in human erythrocytes by reversed phase high performance liquid chromatography
Authors: Kojima Tsukasa , Nishina Toshihiro , Kitamura Motoshi , Yamanaka Hisashi , Nishioka Kusuki 
Published: May 2005

AbstractA new method for the determination of adenine phosphoribosyltransferase (APRT) activity in human erythrocytes is described. APRT activity was assayed by a non‐radiochemical method in which adenosine monophosphate (AMP) and AMP metabolites produced from a substrate adenine were converted to inosine by alkaline phosphatase and adenosine deaminase. The inosine thus produced was quantitated by reversed phase HPLC. This method was simple, precise, sensitive and free from interference with other co‐existing erythrocyte enzymes. Four patients with 2,8‐dihydroxyadenine urolithiasis and others with several disorders in purine metabolism have been studied, showing that the present method is clinically useful for the diagnosis and the evaluation of the severity of some human diseases.
Characterization of human progesterone receptor by high performance hydrophobic interaction chromatography
Authors: Levy A. , Boyle D. M. , van der Walt L. A. 
Published: May 2005

AbstractHigh performance hydrophobic interaction chromatography has been used to separate progestin receptors (PRs) from human uterus and from the T47D human breast cancer cell line. Reproducible separations of high resolution were achieved using a TSK Phenyl‐5PW column and a reverse salt gradient of 400 mM to 0 mM sodium sulfate in phosphate buffer, pH 7.4. Peaks of radioactivity exhibiting hydrophobic behaviour were isolated, as well as a smaller proportion of specific bound receptors located in the void volume fraction. No differences in retention times were observed between uterine and breast cell line samples. When the technique was used in conjunction with rapid vertical tube sucrose density gradient centrifugation, the 8S sedimenting PR from fresh, low‐salt cytosol always eluted with a retention time of 24 min. The natural 4S receptor chromatographed as a single peak at 29 min while the 4S receptor species from high‐salt cytosol appeared as two distinct peaks of radioactivity with retention times of 29 and 33 min. While specific binding was shown to occur in the void volume of the column, the origin of these receptors were indeterminate. These results would suggest that under these conditions the 8S receptor occurs as a single hydrophobic class of protein, whereas the data provides evidence that transformed 4S receptor may be proportioned into two unequal entities as a function of exposure to salt.
Direct enantiomeric high performance liquid chromatographic separation of aminoglutethimide and its major metabolite on a series of Chiralcel OD and Chiralcel OJ columns and its application to biological fluids
Authors: Aboul‐Enein Hassan Y. , Islam M. Rafiqul 
Published: May 2005

AbstractA direct, isocratic, sensitive and precise liquid chromatographic method is presented for the enantiomeric separation of aminoglutethimide (AG) and its acetylated metabolite (AcAG) using cellulose tris‐3,5‐dimethyl phenyl carbamate (Chiralcel OD) and cellulose tris(4‐methylphenyl benzoate) ester (Chiralcel OJ) columns in series. The enantiomeric elution order is determined by separate chromatography of the racemate AG and racemate AcAG and of their separate enantiomers under similar conditions. This method has been used to determine and identify the enantiomers of AG and AcAG in the urine sample collected from a metastatic breast cancer patient after administration of AG for 24 h. Large amounts of (+)‐R‐AG are excreted unchanged in the urine together with smaller quantities of (+)‐R‐AcAG, while most of the (−)‐S‐AG is metabolically converted into (−)‐S‐AcAG.
Separation of β‐ and γ‐tocopherols in serum by high performance liquid chromatography
Authors: Al‐Meshari Abdul Aziz , Aleem Mohammed A. 
Published: May 2005

AbstractA simple and sensitive high performance liquid chromatographic method for the analysis of tocopherols (α, β, γ and δ) in serum with UV detection is described. In normal phase mode excellent separation of positional isomers (β and γ) was achieved by adjusting the proportion of isopropanol in the mobile phase. Detection limits for both β and γ were 0.62 mg/L and 0.42 and 1.2 mg/L for α and δ isomers, respectively. Measurement of all the tocopoherol structural isomers (α, β, γ and δ) in a sample required only 400 μL of serum and each run was completed in less than 22 min.
Inorganic supports coated with N‐substituted polyacrylamides: Application to biospecific chromatography of proteins
Authors: Ivanov Alexander E. , Kozlov Leonid V. , Shojbonov Batozhab B. , Zubov Vitaly P. , Antonov Vladimir K. 
Published: May 2005

AbstractWide porous glass (WPG) chemically coated with a poly‐N‐(2‐hydroxyethyl)acrylamide layer is proposed as a carrier of biospecific ligands in affinity chromatography. The method of WPG chemical modification includes synthesis of the γ‐aminopropyl derivative followed by chemical adsorption of poly(p‐nitrophenyl acrylate). Ester groups of the polyacrylate‐coated WPG can be used for coupling the ligands bearing primary amino groups. Condensation of esters with ethanolamine yields a poly‐N‐(2‐hydroxyethyl)acrylamide‐coated support with non‐specific adsorption properties resembling those of Sepharose 4B. Human IgG immobilized on the polyacrylate support was used for isolation of the first complement component from human serum and for its separation into subcomponents C1r, C1s and C1q by a one‐step method. An unbound part of serum may be used as the R1 reagent for determining haemolytic C1 activity. The stepwise elution of C1r, C1s and C1q from the column reflects the course of C1 breakdown after its activation on immune complex formation.
Rapid determination by high performance liquid chromatography of di‐2‐ethylhexyl phthalate in plasma stored in plastic bags
Authors: Dine T. , Luyckx M. , Cazin M. , Brunet Cl. , Cazin J. C. , Goudaliez F. 
Published: May 2005

AbstractA rapid sensitive technique was developed for the analysis of di‐2‐ethylhexyl phthalate (DEHP) in plasma stored in plastic bags by using high performance liquid chromatography (HPLC) with UV detection and a Hypersil ODS column. The compound was easily and efficiently extracted with a mixture of sodium hydroxide and acetonitrile, which allowed the deproteinization of plasma samples. The recovery was greater than 95% and the intra‐ and inter‐assay coefficients of variation were better than 6.5%. The results obtained showed that the amount of DEHP accumulated in plasma varied according to different parameters and depended on the storage conditions (time, temperature and shaking) and also on the lipid content of the stored plasma and the sterilization process of the PVC bags.
Effect of a dual‐head short‐stroke pump on post‐column peroxyoxalate chemiluminescence detection
Authors: Hayakawa Kazuichi , Imaizumi Noriko , Miyazaki Motoichi 
Published: May 2005

AbstractA dual‐head short‐stroke pump has two advantages in the post‐column peroxyoxalate chemiluminescence (PO‐CL) detection system. The first is to increase the mixing efficiency of solutions. The second is to increase the stability of the PO‐CL reaction by keeping the aryl oxalate and hydrogen peroxide solutions separate. The detection sensitivities for six polycyclic aromatic hydrocarbons (PAHs) increased in the present system by using bis(2,4‐dinitrophenyl) oxalate (DNPO) or bis (2,3,4,5,6‐pentafluorophenyl) oxalate (PFPO) instead of such popular aryl oxalates as bis(2,4,6‐trichlorophenyl) oxalate (TCPO) and bis[2‐(3,6,9‐trioxadecyloxycarbonyl)‐4‐nitrophenyl] oxalate (TDPO). Both DNPO and PFPO increased the sensitivities by factors of 4.1–10.2 and 3.5–8.1, respectively. In addition, DNPO was more stable than PFPO in acetonitrile. These results suggest that DNPO is the most useful aryl oxalate for the sensitive PO‐CL detection of PAHs.
A high performance liquid chromatographic assay for AMP‐deaminase activity in the erythrocytes of healthy subjects and patients with inherited purine disorders
Authors: Smolenski Ryszard T. , Montero Celia , Rodgers A. Victoria , Simmonds H. Anne 
Published: May 2005

AbstractA novel method for measuring AMP‐deaminase activity in human erythrocytes is presented, based on the determination of the reaction product, IMP, using high performance liquid chromatography. IMP formation was found to be proportional both to the incubation time and the amount of haemolysate over a wide range. The minimal detectable AMP‐deaminase activity was more than 1000 times lower than the mean activity found in healthy controls (1083 nmol/h/mg Hb). No marked difference of activity was found in the patients with the following inherited purine disorders: familial juvenile gouty nephropathy and deficiencies of adenosine deaminase, hypoxanthine‐guanine phosphoribosyltransferase or adenine phosphoribosyltransferase. The activity in the erythrocytes of patients with chronic renal failure was also similar to controls. The existence of subjects with low erythrocyte AMP‐deaminase activity in the population has been confirmed.
pH‐dependent colum fractionation for characterization of endogenous digoxin‐like immunoractive factors in pregnant urine
Authors: Homma Masato , Hirano Toshihiko , Oka Kitaro 
Published: May 2005

AbstractSamples of pregnant urine were treated with three diatomaceous earth columns to fractionate organic solvent‐soluble components. The first column was pre‐injected with the urine sample. The second and the third columns were pre‐injected with sodium bicarbonate and sodium hydroxide solutions, respectively; these played an important role in capturing acidic components in the urine extract from the first column. Neutral components could be eluted out from the columns with the organic solvent, while the basic components were retained in the first column. Once strongly and weakly acidic components were captured on the alkaline columns, they were separately treated with an acidic mobile phase and recovered. The digoxin‐like activities of each fraction were examined for cross‐reactivity to antidigoxin antibody and inhibitory effects on dog kidney Na+, K+‐ATPase. Both types of reactivity were found in all three fractions and decreased in the following order: strongly acidic, neutral and weakly acidic. The neutral fraction of pregnant urine showed significantly greater cross‐reactivity than that of the non‐pregnant urine. Following hydrolysis of the pregnant urine with β‐D‐glucuronidase, the cross‐reactivity of the neutral fraction increased significantly. High performance liquid chromatographic analysis showed that several components in the neutral fraction had apparently increased after the hydrolysis, showing the possible presence of unknown digoxin‐like components in the pregnant urine.
Determination and purification of metallothioneins by high performance liquid chromatography
Authors: Pan Aihua , Wang Zhenxin , Ru Binggen 
Published: May 2005

AbstractA rapid, reproducible and sensitive high performance liquid chromatography (HPLC) method for the determination and purification of metallothionein‐I (MT‐I) and metallothionein‐II (MT‐II) in mouse and rabbit livers has been developed. Methallothioneins (MTs) were separated by an HPLC anion exchange column, eluted through a linear gradient of Tris buffer and the peak containing MTs was determined by atomic absorption spectrophotometry. Furthermore, the content of MT‐I or MT‐II was calculated by protein peak area in a short time (about 20 min). The sample to be tested was homogenized, centrifuged and saturated by cadmium. MT‐I and MT‐II were eluted at 15.9 and 19.3 min, respectively. The following mouse liver cytosols were tested: controls, Cd‐injected samples and 60Co‐irradiated samples. A detection limit of 5 μg/g liver was established for this method. We have analysed more than 100 biological samples and obtained satisfactory results.
A high performance liquid chromatographic method for the quantitation of flecainide in plasma
Authors: Broly F. , Marecaux P. , Houdret N. , Lhermitte M. , Houssin R. 
Published: May 2005

AbstractA routine high performance liquid chromatographic method for the rapid determination of flecaïnide (Flecaine®), using a novel internal standard, N‐methylflecaïnide, has been developed. After deproteinization of spiked samples, flecaïnide was totally recovered at neutral pH. Flecaïnide and the internal standard were separated on a reversed phase XL 3 μm ODS column using 10 mM phosphate buffer, pH 3.0: acetonitrile (70:30) as mobile phase, in less than 10 min. With spectrofluorometric detection, the limit of quantitation for flecaïnide was 10 n/mL. Intra‐ and inter‐assay precision variations were 0.24% and 1.4%.