摘要:

AbstractWith the view of purifying soluble human brain acetylcholinesterse (AChE) into its separate isoforms, various preparative chromatographic procedures were compared. Chromatofocusing of cerebrospinal fluid (CSF) AChE revealed two major activity peaks, whilst that of caudate nucleus AChE showed one major peak, Both CSF and caudate nucleus AChE eluted at isoelectric points (pI) of between 5.5 and 5.2 Chromatofocusing failed to separate AChE into its individual isoforms, based on qualitative isoelectric focusing. Preparative purification by affinity chromatography showed a better AChE yield with the use of procainamide as a ligand, vis‐à‐vis acridinium. Maximum recovery for CSF and caudate nucleus AChE was 10 and 43% using acridinium and procainamide, respectively. Qualitative analysis by SDS‐PAGE of affinity‐purified AChE revealed four major bands between 50 and 62kDa, corresponding to the catalytic subunits of AChE as verified by an anti‐AChE polyclonal antibody. A size‐exclusion column also allowed brain AChE purification, with the latter eluting at a putative molecular mass of 310 kDa. Unfortunately, cation‐exchange using the state‐of‐the‐art SMART system failed to separate AChE into its isoforms. AChE aggregation is given as one major obstacle precluding good re

ISSN:0269-3879    

DOI:10.1002/bmc.1130080602

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe interaction between 22 anticancer drugs and carboxymethyl‐γ‐cyclodextrin (CM‐γ‐CD) was studied by reversed‐phase charge‐transfer thin‐layer chromatography and the relative strenth of interaction was calculated. CM‐γCD formed inclusion complexes with 11 compounds, the complex always being more hydrophilic than the uncomplexed drug. The inclusion forming capacity of drugs differed considerably according to their chemical structure. Both principal component analysis and cluster analysis found a relationship between the inclusion complex forming capacity and hydrophobicity parameters of anticancer drugs. This result suggests that the preponderant role of hydrophobic interactions is in inclusion

ISSN:0269-3879    

DOI:10.1002/bmc.1130080603

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractCapillary gas chromatography with electron capture detection is described for the quantification of chloral hydrate (CH) and is metabolites trichloroethanol (TCE) and trichloroacetic acid (TCA) in 0.1–1 mL of plasma samples. The method, with 2,2′‐dichloroethanol (DCE) as internal standard, involved extraction of chloral hydrate and trichloroethanol with diethyl ether and methylation of trichloroacetic acid with 3‐methyl‐1‐tolyltriazene (MTT), followed by diethyl ether extraction. The method has a detection limit of 5 ng/mL for CH and TCE and 10 ng/mL for TCA and also allows the determination of TCE‐glucuronide in 0.1–1 mL of plasma samples. It exhibits good linearity and precision. The method was applied to samples of plasma from a neonate after a single dose of 40 mg/kg of chloral hydrate and from an adult after a single dos

ISSN:0269-3879    

DOI:10.1002/bmc.1130080604

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractFluvoxamine, a serotonin re‐uptake inhibitor, was quantified in plasma by modifying a previously published procedure for monitoring plasma concentrations of tricyclic antidepressants. Alkalinized plasma samples were extracted withn‐hexane/isoamyl alcohol, followed by back‐extraction with diluted phosphoric acid, The extracts were analysed by reversed‐phase liquid chromatography using a C‐18 column, with phosphate/acetonitrile as the mobile phase. The assay was linear from 10 to 800 μg/L. Precision studies showed within‐run and day‐to‐day coefficients of variation to be 4.5 and 6.8%, respectively. Desipramine interfered with the detection of fluvoxamine. The assay was used to measure a total of 8 plasma samples from 4 alcohol‐dependent patients medicated with fluvoxamine as an adjunct to relapse prevention psychotherapy. In these patients, the plasma concentrations ranged from 54 to 241 μg/L. Dosage of fluvoxamine, duration of treatment, interval between last dosage and blood collection were associated with effects on plasma concentrations that were consistent with the pharmacokinetic pro

ISSN:0269-3879    

DOI:10.1002/bmc.1130080605

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractA 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

ISSN:0269-3879    

DOI:10.1002/bmc.1130080606

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractA sensitive and specific analytical method has been developed for the determination of a new anxiolytic (CGS 19480A) in human plasma using high performance liquid chromatography (HPLC). The drug and internal standard (CGS 18102A), were extracted with hexane at pH 7. Separations were achieved by reversed phase chromatography on a Nucleosil 5 C18column at a flow rate of 1.0 mL/min. The mobile phase consisted of acetonitrile: 0.01Mphosphate buffer (pH 7): methanol (51:35:14, v:v:v), where the final pH of the mobile phase was adjusted to 4.0 using 85% phosphoric acid. Plasma standard curves were linear from 5.0 to 500 ng/ml, with recovery of the drug being greater than 95% at all concentrations. The method was validated over a concentration range of 5.0 to 500 ng/mL with a limit of quantification of 5.0 ng/ mL.The method was successfully applied to the analysis of clinical samples from a single‐dose safety and tolerability study conducted in six healthy male volunteer

ISSN:0269-3879    

DOI:10.1002/bmc.1130080607

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractHigh‐resolution separation of a PCR product from a mixture of DNA restriction fragments was achieved using capillary gel electrophoresis. The capillary gel electrophoretic separation gives an excellent resolution of two fragments of the 500‐bp PCR product and the 506‐bp DNA fragment, which differs by only 6 bp, and the complete separation of a broader chain lenght range of DNA fragments up to 12kbp within 20min. The plate number of gel‐filled capillary was achieved to be 2 million plates per meter. Capillary gel electrophoresis is applied to the gene diagnosis for heart disease through apolipoprotein E genotyping. The advantages and limitations of capillary gel electrophoresis in the application to PCR analysis and DNA diagnosis are di

ISSN:0269-3879    

DOI:10.1002/bmc.1130080608

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractWe developed a new HPLC method for the determination ofp‐aminobenzoic acid (PABA) and its metabolites (p‐aminohippuric acid,N‐acetyl‐p‐aminohippuric acid,N‐acetyl‐p‐aminobenzoic acid) in urine. As the internal standardm‐hydroxybenzoic acid was used. In the isocratic elution the mobile phase consisted of methanol and 0.02M. ammonium acetate (20:80 v/v, pH 4.0). The separation was carried out on the C18, reversed‐phase column, particle size 5 μm. The separated components were detected at 280 nm. The method can be used in the assessment of the response of pancrease (secretion of digestive enzymes) to soya feeding as well as in the diagnosis of the exocrine pancreatic

ISSN:0269-3879    

DOI:10.1002/bmc.1130080609

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractA Measuring method sensitive to prolyl endopeptidase (EC 3.4.21.26, PEP) activity using native peptides (Arg‐Vasopressin or substance P) as substrates was established. The investigation of three different derivatization reagents, Which had been developed for an amino acid analysis, demonstrated that 4‐fluoro‐7‐nitrobenzo‐2‐oxa‐1,3‐diazole (NBDF) was the most suitable for the detection of Arg‐Gly‐NH2, which was released from Arg‐vasopressin by PEP. Arg‐Gly‐NH2was reacted with NBDF at 65°C for 5 min at pH 7.6 and the reaction mixture was analysed by HPLC on a reverse‐phase column by monitoring the gluorescence intensity. The detection limit was 1 picomol per injection and the linear standard calibration curve could be constructed in the range of 1 to 100 picomol per injection with a 3.0% relative standard deviation. This sensitive detection method for peptide was applied to the measurement of PEP activity Using Arg‐vasopressin as a substrate and 1 × 10−3unit of PEP activity was detectable. This method was also applicable to the measurement of PEP activity Using subsytance P as a substrate by detecting the derivative of its f

ISSN:0269-3879    

DOI:10.1002/bmc.1130080610

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThis report describes high performance liquid chromatographic analysis of transplanted pancreatic islets. A reversed phase ODS column made it possible to measure rat insulin I, II, rat C‐peptide I, II and glucagon simultaneously in isolated rat islets without using radioisotopes. Freshly isolated islets contained 118.0 ± 9.7 ng (mean ± SE,n= 6) insulin and 3.01 ± 0.60 ng glucagon per islet. The insulin I/II ratio was 1.22 ± 0.03. Isolated islets were then culturedin vitroor transplanted into mice under the renal capsule. Transplantation induced mild hypoglycemia in the recipients. The graft mean survival time was 7.2 ± 0.4 days (n= 5). Both cultured (n= 7) and transplanted (n= 6) islets showed similar alterations of polypepide hormones on day 4. Insulin decreased to one third and glucagon remained unchanged. The insulin I/II ratio increased twofold. In conclusion, it was suggested that the general fate of isolated islets was caused by ischemia and denervation. Relatively, ischemia may not damage α cells but may damage β cells because α cells are peripherally located. Denervation may release β cells from a resting state under neural tonic inhibition. Mild hypoglycemia and an increased insulin I/II ratio were related to the accelerated insulin synthesis in the isola

ISSN:0269-3879    

DOI:10.1002/bmc.1130080611

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY