bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of glutathione and related aminothiols by gas chromatography with flame photometric detection
Authors: Kataoka Hiroyuki , Takagi Kiyomi , Makita Masami 
Published: May 2005

AbstractA selective and sensitive method for the determination of glutathione (GSH) and related aminothiols such as cysteine (Cys), cysteinylglycine (CysGly) and γ‐glutamylcysteine (γ‐GluCys) by gas chromatography (GC) has been developed. GSH and related aminothiols were converted into their N, S‐isopropoxycarbonyl methyl ester derivatives and measured by GC with flame photometric detection using a short capillary column (5 m × 0.53 mm i.d.) of cross‐linked DB‐1. The calibration curves were linear in the range 1–25 nmol for GSH and in the range 0.2–5 nmol for other aminothiols, and the detection limits of GSH, Cys, CysGly and γ‐GluCys were approximately 5, 0.2, 0.3 and 0.5 pmol per injection respectively. This method was successfully applied to blood samples without prior clean‐up, and GSH and related aminothiols in these samples could be analysed without any influence from coexisting substances. Overall recoveries of GSH and other aminothiols added to blood samples were 88–107%. The analytical results of free and total blood GSH and related aminothiols in normal subjects are presented.
High‐performance liquid chromatographic separation of penicillamine enantiomers labelled with N‐[4‐(6‐dimethylamino‐2‐benzofuranyl)phenyl]maleimide on a chiral stationary phase
Authors: Nakashima Kenichiro , Ishimaru Tomoko , Kuroda Naotaka , Akiyama Shuzo 
Published: May 2005

AbstractPenicillamine enatiomers derivatized with N‐[4‐(6‐dimethylamino‐2‐benzofuranyl)phenyl]maleimide (DBPM) were separated and determined by high‐performance liquid chromatography. A fluorogenic reagent, DBPM easily reacted with D‐ or L‐penicillamine to give each two kinds of strong fluorescent derivatives (D1−, D2−, L1− and L2 DBPM), which could be separated on a Pirkle‐type chiral stationary phase using an eluent of 75% aqueous methanol solution containing 0.15 M CH3COONH4 and 0.05 M tetra‐n‐butylammonium bromide. Two of the peaks (D1− or L1‐DBPM), having a shorter retention time than the others, had almost the same retention times (25 min for D1‐DBPM and 25.7 min for L1‐DBPM). The retention times of the peaks eluted later were 28 min and 31.6 min for D2‐ and L2‐DBPM respectively. Linear calibration curves over the range of 2–50 pmol per injection were obtained for D‐and L‐penicillamines with a detection limit of 290 and 350 fmol at respectively at a signal‐to‐noise ratio of 3. Using the proposed method, the absence of contamination of L‐penicillamine in a commercially available D‐penicillamine preparation (capsule) was confirmed.
Reversed‐phase high‐performance liquid chromatography of fullerenes with tetrahydrofuran‐water as a mobile phase and sensitive ultraviolet or electrochemical detection
Authors: Santa Tomofumi , Koga Daisuke , Imai Kazuhiro 
Published: May 2005

AbstractFullerenes (C60 and C70) were separated on a reversed‐phase high‐performance liquid chromatography column with a mobile phase of tetrahydrofuran‐water (70:30, v/v) and detected with ultraviolet or electrochemical detection. A baseline resolution of C60 and C70 was achieved with a capacity factor values of 7.6 and 10.8 respectively and a resolution of 3.7. The detection limit for C60 was 0.1 pmol on column and was nearly the same for both detection methods.
The application of affinity chromatography for quantitative determination of metallothionein in physiological fluids by an indirect method based on analysis of metal contentse
Authors: Kabziński Andrzej K. M. , Takagi Toshio 
Published: May 2005

AbstractAn indirect method, based on the analysis of metal contents, for the determination of metallothionein (MT) in body fluids is described. Affinity chromatography gel was used as a solid phase extraction (SPE) support for preconcentration of MT Proteins and metals bound to MT from spiked water and human urine samples. The results showed a good correlation between the concentration of MT proteins added to water or physiological human urine and the concentration of protein indirectly determined by atomic absorption spectrometry (AAS) recovered by the SPE‐affinity chromatography technique and calculated from the metal concentration. The present method can be used in toxicological analysis for determination of MT concentration in physiological fluids in subjects exposed to heavy metals.
Simultaneous determination of nadolol enantiomers in human plasma by high‐performance liquid chromatography using fluorescence‐detection
Authors: Belas Frank J. , Phillips Mark A. , Srinivas Nuggehally R. , Barbhaiya Rashmi H. , Blair Ian A. 
Published: May 2005

AbstractA high‐performance liquid chromatographic assay is described for the separation and quantification of nadolol isomers in human plasma. The isomers were quantified using reverse‐phase HPLC and fluorometric detection after derivatization with the chiral reagent R(‐)‐1‐(naphthyl)ethylisocyanate [R(‐)‐NEI]. The N‐isopropyl analogue (one isomer) of nadolol was used as the internal standard. The method was reproducible based on precision studies where the percent relative standard deviation was less than 15%. The lower limit of quantitation for each isomer was 2.5 ng/mL. This method was used to evaluate the pharmacokinetic profile of nadolol isomers in human subjects following both single and multiple oral dosing.
The development of a sensitive myo‐inositol analyser using a liquid chromatograph with a post‐label fluorescence detector
Authors: Inamoto Yukiko , Hiraga Yayoi , Hanai Toshihiko , Kinosita Toshio 
Published: May 2005

AbstractA sensitive liquid chromatographic analysis for myo‐inositol was developed using glycocyamine as the postlabelling reagent. The sensitivty was 500 pmol/injection. The system was applied to analyse myo‐inositol in sera from eight patients with chronic renal failure. The average concentration of serum myo‐inositol was 498.6 ± 257.0 μmol/L before haemodialysis, and 244.0 ± 131.1 μmol/L after haemodialysis. These results indicated that the kidney is the main site of myo‐inositol metabolism.
Relationships between binding of benzodiazepines to alpha‐1‐acid glycoprotein and human serum albumin and their retention on the protein and octadecylsilane columns
Authors: Sadlej‐Sosnowska Nina 
Published: May 2005

AbstractCorrelation between binding parameters of 6 benzodiazepines to free human serum albumin (HSA) and chromatogrphic retention parameters on the HSA stationary phase (HSA‐SP) was better than the similar correlation with alpha‐1‐acid glycoprotein (AGP). Still better correlation was obtained between binding to both proteins and retention on an octadecylsilane (ODS) column. For 12 benzodiazepines the correlations of the retention parameters on both protein columns with the retention on the ODS column were additionally investigated. In the case of HSA this correlation was good.
A novel method for the amino acid sequence/configuration determination of peptides containing D/L‐amino acids utilizing a fluorogenic edman reagent, 7‐N,N‐dimethylaminosulphonyl‐4‐(2,1,3‐benzoxadiazolyl)isothiocyanate (DBD‐NCS)
Authors: Imai Kazuhiro , Matsunaga Hirokazu , Fukushima Takeshi , Santa Tomofumi , Homma Hiroshi , Nakashima Kenichiro , Akiyama Shuzo 
Published: May 2005

AbstractA novel method for the amino acid sequence and configuration determination of peptides containing D‐ or L‐amino acids is presented. An enkephalin analogue, [D‐Ala2, D‐Leu5]enkephalin (Tyr‐Ala‐Gly‐Phe‐Leu) was derivatized with a fluorogenic Edman reagent, 7‐N,N‐ dimethylaminosulphonyl‐4‐(2,1,3‐benzoxadiazolyl) isothiocyanate (DBD‐NCS), cleaved and cyclized with trifluoroacetic acid at 50 oC for 1 min and the resultant thiazolinaone derivative (DBD‐thiazolinyl‐L‐isomer) on a phenylcarbamylated cyclodextrin column: The separation factor (α) for D‐ and L‐isomers was 1.09. The column eluate was monitored fluorometrically at 524 nm with excitation at 387 nm. The detection limit was about pmol range. The same treatment adoted for the residual peptide, Ala‐Gly‐Phe‐Leu, gave DBD‐thiazolinyl‐D‐Ala (α = 1.09 for D,L‐Phe) with the lesser amount of L‐analogue (about 20%). In the same manner, Gly and L‐Phe (α = 1.09) were detected. The method might be useful for the study of aging of proteins such as eye lens and the amyloid proteins derived from Alzheimer's disease.
Determination of argininosuccinate lyase in human serum by ion‐pair reversed phase liquid chromatography
Authors: Canepari S. , Carunchio V. , Girelli A. M. , Messina A. 
Published: May 2005

AbstractA new assay for argininosuccinate lyase based on the separation of the enzymatic reaction mixture components by an ion‐pair reversed phase mechanism is reported. The determination of enzyme activity is performed after direct injection by UV detection of the fumarate formed. The chromatographic analysis time is 8 min and a detection limit of 0.4 U/L is achieved. The HPLC method is highly accurate, sensitive and precise. The simple procedure makes this method suitable for the routine determination of ASAL activity in human serum samples.
The quantitative analysis of inhalational anaesthetics in forensic samples by gas chromatography/mass spectrometry/selected ion monitoring
Authors: Maruyama Kyoko , Takatsu Akihiro , Obata Toru 
Published: May 2005

AbstractThe quantitative analysis of volatile anaesthetics for biomedical applications by means of gas chromatography/mass spectrometry/selected ion monitoring (GC/MS/SIM) was studied. Xenon gas was selected as an internal standard for the assay by adding to a closed system, because of its stability and inactivity. In the assay of inhalational anaesthetics, isoflurane and nitros oxide (laughing gas), in forensic samples (serum and cerebrospinal fluid), the calibration of the anaesthetic was linear from 0.12 to 12 nmol/mL in isoflurane and from 30 to 300 nmol/mL in nitrous oxide. Our results suggest that this new method is suitable for the quantitative analysis of inhalational anaesthetics in the biomedical field.
Capillary gas chromatographic analysis of protein amino acids as their N(O,S)‐isobutoxycarbonyl methyl ester derivatives
Authors: Matsumura Sayuri , Kataoka Hiroyuki , Makita Masami 
Published: May 2005

AbstractA simple and rapid method for the determination of the 22 protein amino acids by capillary gas chromatography is described. The amino acids were converted into their N(O,S)‐isobutoxycarbonyl (isoBOC) methyl ester derivatives and measured by GC with flame ionization detection using a DB‐17 capillary column. Arginine was converted into ornithine by arginase treatment prior to the isoBOC reaction. The N(O,S)‐isobutoxycarbonylation of amino acids with isobutyl chloroformate was completed within 15 s by sonication in aqueous alkaline media. All of the derivatives were quantitatively resolved as single symmetrical peaks within 9 min by GC on a single column. The detection limits of amino acids were 0.2–4.0 ng per injection, and the calibration curves were linear in the range 0.2–50 μg for each amino acid. This method was successfully applied to protein hydrolysate samples. The analytical results of amino acid compositions of several proteins are presented.
Stereoselective analysis of nadolol in human plasma
Authors: Srinivas N. R. , Shyu W. C. , Shah V. R. , Campbell D. A. , Barbhaiya R. H. 
Published: May 2005

AbstractA steroeselective method, involving a single liquid‐liquid extraction step, was developed and validated for the analysis of nadolol in human plasma. The assay involved extraction of nadolol and desmethyl‐nadolol as internal standard (IS) from alkalinized plasma into dichloromethane. The organic solvent was separated and evaporated under nitrogen at 40°C. A chiral derivatization scheme with (R)‐(−)‐napthylethylisocyanate (50 μL of 0.1% solution in dichloromethane for 60 min) was employed to convert the enantiomers of nadolol into the corresponding diastereomeric derivatives. The residue was reconstitutd in the mobile phase and injected onto a C‐18 column. The mobile phase was a mixture of methanol: tetrahdrofuran: water (52:7:41 by vol) containing about 0.001% v/v of both phosphoric acid and tetramethylethylenediamine. Fluorimetric detection was performed at excitation 230 and emission 330 nm. The assay was specific for the enantiomers of nadolol and the lower limit of quantitation was 2 ng/mL for of the enantiomers. Analysis of quality control samples resulted in precision estimates of 7% RSD for inter‐assay and 10.1% RSD for intra‐assay and the predicted concentrations deviated less than 9.4% of the nominal values for the four enantiomers. The extraction recoveries of the individual enantiomer was about 70%. Stability of nadolol enantiomers were established for four freeze/thaw cycle periods and in the autosampler at 5°C for at least 116 h.
Selective and sensitive determination of pamidronate in human plasma and urine by gas chromatography with flame photometric detection
Authors: Sakiyama Norihisa , Kataoka Hiroyuki , Makita Masami 
Published: May 2005

AbstractA rapid, selective and sensitive method for the determination of pamidronate in human plasma and urine samples by gas chromatography (GC) has been developed. After deproteinization of the sample with trichloroacetic acid, pamidronate was converted into its N‐isobutoxycarbonyl methyl ester derivative and measured by GC with flame photometric detection (FPD), using a HP‐1 capillary column. The derivative preparation and GC analysis were accomplished within 30 min. The derivative was sufficiently volatile and stable, giving a single and symmetrical peak, and provided an excellent FPD response. The detection limit of pamidronate, at a signal‐to‐noise ratio of 3, was ca. 100 pg injected, and the calibration curve for this compound in the range 20–1000 ng was linear and sufficiently reproducible for quantitative determination. This method could be successfully applied to plasma and urine samples without a preliminary clean‐up except for deproteinization with trichloroacetic acid, and pamidronate could be measured without any influence from coexisting substances. Overall recoveries of pamidronate added to plasma and urine samples were 93–97%. The coefficients of variation for intra‐assay and inter‐assay of pamidronate in these samples were 1.0–7.9% (n = 3) and 4.1–8.3% (n = 6), respectively.
Rapid determination of O‐ and P‐cresol isomers in urine from workers exposed to toluene by high‐performance liquid chromatography using a graphitized carbon column
Authors: Schlatter J. , Astier A. 
Published: May 2005

AbstractA simple and rapid procedure is described that permits the simultaneous determination of o‐ and p‐ cresol in urine of workers or other individuals exposed to toluene. The urine samples are enzymatically hydrolysed and analysed by high‐performance liquid‐chromatography with a detetion limit of 0.2 mg/L, one fifth of the biological threshold limit value for o‐cresol (1 mg/g ), a specific marker of toluene exposure. A graphitized carbon column Hybercarb‐S, that exhibits an excellent selectivity for aromatic positional isomers, was used with 1% phosphoric acid‐acetonitrile (70:30, v/v) as mobile phase and a detection wavelength of 271 nm. The overall accuracy for o‐cresol determination was 4.5% at 5 mg/L and 8% at 0.5 mg/L. The cresol isomers were sufficiently resolved from endogenous materials to avoid the need for any extraction step, and the method appears suitable for monitoring workers accurately under the permissible level of exposure for occupational medicine purpose.
Metabolic control and compartmentation in single living cells
Authors: Kohen Elli , Kohen Cahide , Hirschberg Joseph G. , Wouters Alain W. , Thorell Bo , Westerhoff Hans V. , Charyulu Komanduri K. N. 
Published: May 2005

AbstractMicrospectrofluorometry of cell coenzymes (NAD(P)H, flavins) in conjunction with sequential microinjections into the same cell of metabolites and modifiers, reveals aspects of the regulatory mechanisms of transient redox changes of mitochondrial and extramitochondrial nicotinamide adenine dinucleotides. The injection of ADP in the course of an NAD(P)H transient produced by glycolytic (e.g. glucose 6‐phosphate, G6P) or mitochondrial (e.g. malate) substrate leads to sharp reoxidation (state III, Chance and Williams, 1955), followed by a spontaneous state III to IV transition, and an ultimate return to original redox steady state. The response to ADP alone is biphasic, i.e. a small oxidation‐reduction transient followed by a larger reverse transient. Similarities between responses to injected ATP and ADP suggest possible intracellular inter‐conversions. Sequential injections of glycolytic and Krebs cycle substrates into the same cell, produce a two‐step NAD(P) response, possibly revealing the intracellular compartmentation of this coenzyme. A two‐step NAD(P)H response to sequentially injected fructose 1,6‐diphosphate and G6P indicates the dynamic or even structural compartmentation of glycolytic phosphate esters in separate intracellular pools. The intracellular regulation and compartmentation of bioenergetic pathways and cell‐to‐cell metabolic inhomogeneities provide the basis on which the quantitative biochemistry of the intact living cell may be reconciled with these in situ findings.
Fibronectin is not a serum spreading factor for HeLa cells
Authors: Michl J. , Baudyšová M. , Sochorová L. , Deyl Z. 
Published: May 2005

AbstractThe spreading of HeLa cells on plastic substratum is mediated by fibronectin‐depleted foetal calf serum but not by fibronectin isolated by gelatin‐Sepharose affinity chromatography. The same is true for freshly explanted chick embryonic chondrocytes. In contrast, BHK cell spreading exceeds 67% after 120 min at 37°C in fibronectin‐supplemented (10 μg ml−1) serum‐free medium. Long‐term cultivation of HeLa cells in Eagle's MEM supplemented with fibronectin‐free serum is associated with the accumulation of cells in mitosis or before cytokinesis; many cells die and the remaining living cells, characterized by marked changes in morphology, multiply very slowly. It can be concluded therefore that fibronectin does not produce spreading in HeLa cells but forces them into mitosis.
Quantitative cytochemistry of blood neutrophils in myelodysplastic syndromes and chronic granulocytic leukaemia
Authors: Schofield K. P. , Stone P. C. W. , Kelsey P. , Leyland M. J. , Stuart J. 
Published: May 2005

AbstractQuantitative cytochemistry of components of blood neutrophil azurophilic granules (myeloperoxidase, chloroacetate esterase, β‐glucuronidase, and acid phosphatase) and specific granules (lactoferrin) has been performed by scanning and integrating micro‐densitometry in 13 patients with a myelodysplastic syndrome and 11 patients with chronic granulocytic leukaemia. Both patient groups showed a reduction of enzyme activity in azurophilic granules, and also of lactoferrin, consistent with abnormal development of neutrophil granules. These cytochemical changes in blood neutrophils are similar to those found in acute myeloid leukaemia, are consistent with a leukaemic maturation defect, and may be of diagnostic value.
Tumour localization of uroporphyrin isomers I and III and their correlation to albumin and serum protein binding
Authors: El‐Far Mohamed A. , Pimstone Neville R. 
Published: May 2005

AbstractWe were the first to report the superiority of uroporphyrin I (UROP I) as a tumour localizer when compared to haematoporphyrin derivative (HPD). In this study, we compared both isomers of UROP, i.e. I and III, in a KHJJ mammary carcinoma mouse model. Six and 18 h after UROP administration, the tumour, skin and gut porphyrin (P) content was quantitated. Tumour UROP I levels were always at least 50% higher than UROP III in tumour, whereas both isomers were barely detectable in the skin and gastrointestinal tract. We then explored the possibility that tumour P uptake might relate in part to the affinity of circulating P to mouse serum proteins (MSP), in particular, the major binding protein constituent, albumin. Copro‐P III, deutero‐P 2,4 disulphonic acid (DP), proto‐P IX (PP) and heptacarboxylic P I (Hepta I) which in our mouse tumour model do not localize in malignant tissue, were compared to UROP I and III. The P was mixed with 0.775 μM human serum albumin (HSA) at different molar ratios (HSA:P range 2–8) and the unbound P concentration quantitated using an Amicon CF‐25 membrane cone with centrifugation. The percentage free P was significantly higher for UROP I (92–98%) than III (82–95%) and significantly more than that observed with non‐tumour localizing P studied. Similar data were obtained with MSP. This is consistent with the notion that enhanced uptake and retention (particularly UROP I) by malignant neoplastic tissue might reflect a higher affinity for UROP by tumour constituents than by circulating proteins. We conclude, (i) that serum proteins, particularly albumin, may play a significant role in governing the localization of P in tissues and, (ii) UROP clinically is ideally suited as a diagnostic marker of pre‐ or early mucosal malignancy as minimal retention by skin and gut would increase fluorescence specificity and diminish photocutaneous side effects.
Comparison of two cell isolation procedures to study in vitro intestinal wall biotransformation in control and 3‐methyl‐cholanthrene pretreated rats
Authors: Borm Paul J. A. , Koster Andries Sj. , Frankhuijzen‐Sierevogel Ank , Noordhoek Jan 
Published: May 2005

AbstractTwo cell isolation procedures, i.e. a scraping/collagenase‐treatment and a new vibration procedure in EDTA containing medium, were used to isolate intestinal epithelial cells. In both cell populations the metabolism of 7‐ethoxycoumarin and 7‐hydroxycoumarin was studied. Moreover, the time course and extent of induction of both steps in the biotransformation were investigated after oral 3‐methylcholanthrene pretreatment of the rats. Twenty four hours after 3‐methylcholanthrene pretreatment (20 mg kg−1) monooxygenase activity was induced about 6‐fold and 2.5‐fold when studied with cells of the vibratory and enzymic procedures, respectively. Control 7‐ethoxycoumarin deethylase activity and 7‐hydroxycoumarin glucuronidation were about the same when comparing both methods for cell‐isolation. The formation of glucuronides in cells (both methods) is significantly lowered by 3‐MC pretreatment, while sulphation remains unaffected. Results indicate that using enzymic treatment of mucosal scrapings, cell‐populations are obtained containing relatively more differentiated (tip) cells. A number of advantages of the new (vibration) method are: better recovery, viability and reproducibility.
Possible mechanism for target cell lysis by cytotoxic T‐cells
Authors: Friedberg R. C. , Bitensky L. , Chayen J. , Muir I. H. , Askonas B. A. , Taylor P. M. 
Published: May 2005

AbstractThe mechanism of the lysis of target cells by cytotoxic T‐cells (Tc) is still obscure; there is no evidence for transfer of material from the Tc and prior to lysis, despite intimate contact, the plasma membranes of both types of cell appear to remain intact. The effects on the target cell lysosomes of brief contact between anti‐viral Tc and targets bearing both the appropriate histocompatibility and viral antigens, have been examined cytochemically. Both the distribution of acid phosphatase activity and the percentage bound lysosomal naphthylamidase activity indicated that, in virus‐infected target cells exposed to Tc, the lysosomal membranes became totally labilized. Thus the contact between Tc and targets appears to cause sufficient perturbation of the target plasma membrane as to cause the intracellular release of some agent that activates ‘suicide capsule’ lysosomes.