Masaaki Kai

• Nagasaki University

Hepatitis C virus protease (HCV-PR) and human immunodeficiency virus protease (HIV-PR) are important for virus maturation, and thus can be used as potential target molecules for the development of antiviral drugs for the treatment of viral infections. In this study, a novel assay was developed to determine HCV-PR activity. This assay is based on a...

We developed an assay method for measuring dihydroorotate dehydrogenase (DHODH) activity in cultured HeLa cells and fibroblasts, and in stage III stomach cancer and adjacent normal tissues from the same patient. The assay comprised enzymatic reaction of DHODH with a large amount of dihydroorotic acid substrate, followed by fluorescence (FL) detecti...

Aptamers have a promising role in the field of life science and have been extensively researched for application as analytical tools, therapeutic agents and as vehicles for targeted drug delivery. Compared with RNA aptamers, DNA aptamers have inherent advantages in stability and facility of generation and synthesis. To better understand the specifi...

Testing for HIV drug resistance is essential to the care of HIV-infected patients. Although direct phenotypic resistance assays are highly reliable, the current recombinant virus-based method is costly and time-consuming. Here, we report a novel fluorometric assay for phenotypic differentiation of drug-resistant mutants of human immunodeficiency vi...

Abstract We have developed a novel method for sensitive chemiluminescence (CL)-imaging detection of DNA by using a macromolecular probe synthesized by attaching multiple molecules of horseradish peroxidase (HRP) and biotin in dextran backbone. The probe formed a macromolecular assembly by binding to streptavidin which specifically recognized biotin...

Orotic acid is an intermediate in the synthesis pathway of uridine-5'-monophosphate, and increases in body fluids of patients suffering from hereditary disorders such as orotic aciduria and hyperammonemia. In this study, we developed a spectrofluorometric method with or without high-performance liquid chromatography for the selective and sensitive...

Convenient drug-resistance testing of viral mutants is indispensable to effective treatment of viral infection. We developed a novel fluorometric assay for phenotypic differentiation of drug-resistant mutants of human immunodeficiency virus-I protease (HIV-PR) which uses enzymatic and peptide-specific fluorescence (FL) reactions and high-performanc...

Convenient drug-resistance testing of viral mutants is indispensable to effective treatment of viral infection. We developed a novel fluorometric assay for phenotypic differentiation of drug-resistant mutants of human immunodeficiency virus-I protease (HIV-PR) which uses enzymatic and peptide-specific fluorescence (FL) reactions and high-performanc...

Convenient drug-resistance testing of viral mutants is indispensable to effective treatment of viral infection. We developed a novel fluorometric assay for phenotypic differentiation of drug-resistant mutants of human immunodeficiency virus-I protease (HIV-PR) which uses enzymatic and peptide-specific fluorescence (FL) reactions and high-performanc...

Convenient drug-resistance testing of viral mutants is indispensable to effective treatment of viral infection. We developed a novel fluorometric assay for phenotypic differentiation of drug-resistant mutants of human immunodeficiency virus-I protease (HIV-PR) which uses enzymatic and peptide-specific fluorescence (FL) reactions and high-performanc...

A novel fluorometric method was developed for the sensitive and selective detection of Pro-Gly (PG) and Pro-Gly-Pro (PGP) using 4-chlorobenzene-1,2-diol (4-CBD) as a fluorogenic reagent. The reaction was performed at 37 degrees C for 30 min in the presence of a borate buffer (pH 7.0) and sodium periodate. The resulting fluorescence intensity was me...

Small interfering RNA (siRNA) is a powerful gene silencing tool and has been considered a potential agent for the treatment of many diseases. However, development of safe and effective siRNA delivery systems still remains a great challenge. In this study, we developed a new siRNA delivery system based on the electrostatic encapsulation of siRNA/cat...

A selective, sensitive, and convenient assay for human collagenase is required because of its implication in diseases such as rheumatoid arthritis, osteoarthritis, and tumors. Here, a novel assay for human collagenase activity is described in which enzymatic degradation of native collagen or acetyl peptide is determined by using a fluorogenic react...

We report on an efficient strategy for the preparation of streptavidin (SA)-coated sephadex beads by the reductive amination of the aldehyde groups on the oxidized sephadex beads that were coupled to the free amino groups of SA. The resulting beads have a stable spherical shape with an average diameter of 20–100 μm. The capacity of SA conjugated to...

Fluorescence (FL) derivatization reactions have often been used for the selective determination of bioactive peptides. Herein, a sensitive and selective fluorometric method has been developed for Pro-Gly and Pro-Gly-Pro using a derivatizing reagent 3,4-dihydroxybenzoic acid (3,4-DHBA). In the presence of borate buffer (pH 8.0) and sodium periodate,...

A carbon nanofiber-based luminol-biotin probe was synthesized for the sensitive chemiluminescence (CL) detection of a target protein by grafting luminol and biotin onto an oxidized carbon nanofiber. This carbon nanofiber was prepared by chemical vapor-deposition with methane in the presence of the Ni-Cu-MgO catalyst, which was followed by oxidizati...

The invention provides a method of detecting uracil. The method comprises reacting uracil with a compound represented by the formula (I) in the presence of an oxidant and a base to produce a fluorescent compound represented by the formula (II).

Sensitive and selective assay of collagen is of substantial importance to the diagnostic study of health- and aging-related failures. In this paper, we describe a highly specific and sensitive method for the assay of whole collagens in biological samples using a novel fluorogenic reagent, 3,4-dihydroxyphenylacetic acid (3,4-DHPAA). The 3,4-DHPAA re...

Telomeres are consist of a simple repeating sequences of six bases (TTAGGG)n, with a length of 5,000-15,000 bp, which are located at the end of chromosomes. Telomere DNA has multiple important roles, including cell proliferation and cell cycle regulation. It is of great importance for the detection of telomere. In this study, we constructed dendrim...

For the first time, an amplified chemiluminescence (CL) detection of the telomere DNA spotted on a nylon membrane is described here, based on the direct hybridization with the CL probe of dendrimer-like polymeric DNAs possessing a large number of guanine moieties. This probe was synthesized by sense and antisense hybridization between Y-shaped DNAs...

Cytosine in urine is one of the biomarkers for the diagnosis of metabolic immunodeficiency. It has been mentioned that high level of cytosine is found in urine of children having immunodeficiency. In this study, we have developed a fluorescence (fluorescence) derivatization reaction of cytosine using 4-trifluoromethylbenzamidoxime (4-TFMBAO) as a f...

Chromatographic methods, including liquid chromatography, gas chromatography tandem mass spectrometry, capillary electrophoresis have been applied for the determination of orotic acid in urine samples. However, these methods require expensive instruments [2]. To specifically detect orotic acid in the complex samples, a chemical reaction is necessar...

Telomeres are consist of a simple repeating sequences of six bases, (TTAGGG)n, with a length of 5,000-15,000 bp (1), which are located at the end of chromosomes in vertebrates. Telomere DNA has multiple important roles, including cell proliferation and cell cycle regulation. Conventional genomic telomere DNA detection methods predominantly rely on...

Diimine ligand (DL) 1 significantly exhibited the fluorescence quenching upon binding to guanine. Changing at the para-substituent of the phenyl ring from the hydroxyl to bromo groups reversely enhanced the fluorescence in the presence of guanine. The reverse in the fluorescence selectivity indicated the profound effect of the substituent at the pa...

We propose here a new amplifying strategy that uses hybridization chain reaction (HCR) to detect specific sequences of DNA, where stable DNA monomers assemble on the magnetic beads only upon exposure to a target DNA. Briefly, in the HCR process, two complementary stable species of hairpins coexist in solution until the introduction of initiator rep...

Caspases are the key regulatory factors of apoptosis and also found to be involved in inflammatory cytokinesis. Sensitive and selective determination of caspases has significant importance in evaluation of apoptosis, disease diagnosis and drug development. Here, we developed an assay method for the determination of caspase activity. This method is...

The intracellular levels of cyclic AMP (cAMP) increase in response to cytotoxic concentrations of L-DOPA in PC12 cells, and forskolin that induces intracellular cAMP levels either protects PC12 cells from L-DOPA-induced cytotoxicity or enhances cytotoxicity in a concentration-dependent manner. This study investigated the effects of cAMP induced by...

A novel fluorescence (FL) reaction for N-terminal Gly-containing peptides has been developed using 3,4-dihydroxyphenylacetic acid (3,4-DHPAA). The reaction of the peptides with 3,4-DHPAA was carried out in borate buffer (pH 8.0) in the presence of sodium periodate at 37°C for 10 min, and the FL was measured with a spectrofluorimeter at the excitati...

In the present study, we synthesized dextran (MW = ca. 2,000 kDa)-based macromolecular probes containing multiple molecules of alkaline phosphatase (ALP) as a signal-trigger enzyme and of biotin as an assembly mediator. The ALP and biotin molecules were covalently attached into the dextran backbone after the formation of aldehyde groups into the ma...

We synthesized dextran-based macromolecular probes carrying multiple molecules of horseradish peroxidase (HRP) as a signal-trigger enzyme and of biotin as an assembly mediator without losing the enzymatic activity. Multiple attachments of HRP and biotin to the dextran backbone were readily accomplished after the formation of aldehyde groups into th...

A method for sequence analysis and identification of phosphoamino acids in peptides based on high performance liquid chromatography (HPLC) is described. The peptides were derivatized with an Edman type reagent, 4-(1'-cyanoisoindolyl)phenylisothiocyanate (CIPIC) and subsequently cleaved to generate stable and fluorescent 4-(1'-cyanoisoindolyl)phenyl...

Telomere DNA is related to cell aging and cancer genesis because the telomeric region of DNA sequences at chromosome ends are shortened with cell divisions. Therefore, a sensitive and specific detection method is required for the telomere DNA. Here we propose a chemiluminescence (CL)-based method for the sensitive detection of telomere DNA in human...

A novel chemiluminescent (CL) technique for the rapid determination of proteins on a membrane is described. The method utilizes an interaction between luminol-labeled alginic acid macromolecule and proteins. The synthesis of the macromolecular probe consists of the oxidation of alginic acid with NaIO(4), the introduction of luminol through imine fo...

L-DOPA therapy for Parkinson's disease has a double-edge effect on nigrostriatal dopaminergic neurons: L-DOPA increases the intracellular level of dopamine, but it induces neuron cytotoxicity in a concentration-dependent manner. To investigate the molecular signaling mechanisms that underlie the concentration-dependent effects of L-DOPA on cell via...

We report on a highly sensitive aptameric assay system for the determination of IgE, where a special chemiluminescence (CL) reagent, 3,4,5-trimethoxylphenylglyoxal (TMPG), acts as the signaling molecule and polystyrene beads as the amplification platform. Briefly, a "sandwich-type" detection strategy is employed in our design, where magnetic beads...

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Facile and specific methods to quantify a nucleobase in biological samples are of great importance for diagnosing disorders in nucleic acid metabolism. In the present study, a novel fluorogenic reaction specific for uracil has been developed. The reaction was carried out in an alkaline medium containing benzamidoxime and K(3)[Fe(CN)(6)] which were...

Herein, we develop a novel chemiluminescence (CL) approach with high sensitivity and excellent selectivity, by taking advantage of magnetic beads as preconcentration carriers and polystyrene microspheres as an amplification platform. Briefly, a 'sandwich-type' detection strategy is employed in our design, which involves capture probe DNA immobilize...

Effective recognition and quantitative analysis of the prion protein are important in drug discovery and diagnosis for prion diseases, such as bovine spongiform encephalopathy and Creutzfeldt-Jakob diseases. We have developed a high-throughput method for a specific and sensitive determination of prion protein on a solid-phase membrane, based on a c...

A highly selective and facile assay of human immunodeficiency virus protease (HIV-PR) has been required for the screening of medicinal inhibitors and also for classifying the subtypes of HIV in the therapeutic treatment of acquired immune deficiency syndrome (AIDS). This article describes a novel assay method of HIV-PR based on the selective fluoro...

Facile and non-radioactive methods are desired for the sensitive detection and quantification of various proteins. Herein we describe a novel chemiluminescence (CL)-detection method of particular proteins based on direct binding of a dextran-luminol-biotin (DLB) CL polymer to the proteins on a poly(vinylidene difluoride) membrane. Among 32 kinds of...

We have developed a novel sensitive chemiluminescence (CL) aptasensor for the target assay as exemplified by using adenosine as a model target. In this work, we have demonstrated the signaling mechanism to make detection based on magnetic separation and 3,4,5-trimethoxyl-phenylglyoxal (TMPG), a special CL reagent as the signaling molecule, which re...

P-type Bi2Te3-based thermoelectric semiconductors were prepared, having a grain-refined microstructure and a preferred orientation of anisotropic crystallographic structure. Disks with a nominal composition of Bi0.5Sb1.5Te3.0 were cut from an ingot grown by the vertical Bridgman method (VBM) and deformed at 473 K under a pressure of 6.0 GPa by high...

Bi2Te3-related thermoelectric semiconductors were prepared by the mechanical alloying (MA) and the vertical Bridgman (VBM)-High Pressure Torsion (HPT) methods. Structures and electric properties of these alloys were then investigated. These samples had a nominal composition of Bi0.5Sb1.5Te3.0 with 0.07 mass% excess Te. The MA sample was sintered in...

Chemiluminescent (CL) detection techniques for DNA assays and immunoassays have become very popular in recent years. This review discusses recent advances in those CL assays that have occurred over the last few years. In the monoplex assay section, different classes of CL labels including nanoparticle, DNAzyme, acridinium ester, enzyme and luminol-...

A series of diimine ligands (DLs) have been synthesized and evaluated for their non-enzymatic chemiluminescence (CL) enhancement of isoluminol or luminol-containing compounds. Of the DLs, N,N'-bis(m-hydroxylbenzylidene)propylenediamine (DL 10) was found to greatly enhance their CLs approximately 40 folds for isoluminol, 10 folds for luminol and 6 f...

Experiments were conducted on a Mg–9% Al alloy to evaluate the microstructural characteristics and the tensile properties at elevated temperatures after processing by high-pressure torsion (HPT) at room temperature and at 423 K. Ultrafine grain sizes were achieved by processing samples in both an extruded and a cast condition. The results demonstra...

The effects of 3,4-dihydroxyphenylalanine (l-DOPA) on dopamine biosynthesis and cytotoxicity were investigated in PC12 cells. l-DOPA treatment (20-200 microM) increased the levels of dopamine by 226%-504% after 3-6 h of treatment and enhanced the activities of tyrosine hydroxylase (TH) and aromatic l-amino acid decarboxylase (AADC). l-DOPA (20-200...

Prepared were p-type Bi2Te3-based thermoelectric semiconductors, having a grain-refined microstructure and a preferred orientation of anisotropic crystallographic structure. Disks with a nominal composition Bi0.5Sb1.5Te3.0 were cut from an ingot grown by the vertical Bridgman method (VBM) and deformed at 473 K under a pressure of 6.0 GPa by high pr...

Telomerase shows increased activity in most human cancers and germ line cells, but not in normal human somatic cells. We describe a novel chemiluminescence method for the facile assay of telomerase activity in human cells. The telomerase substrate was incubated with the cell lysate containing various amounts of telomerase, and then the telomerase p...

A modified Edman degradation method where fluorescent derivatives of amino acids were generated from the postcleavage products of a peptide is described. In the method, the target peptide was applied onto double glass fiber membranes in a small filter disk (4 mm i.d.) and then treated with small amounts of reagents for the manual sequencing of the...

A novel and selective fluorescence reaction is proposed for the quantitative determination of peptides by reversed-phase liquid chromatography (RPLC). A single fluorescent product was formed when a peptide was heated at 120 degrees C for 20 min in a neutral aqueous medium (pH 7.0) containing catechol, sodium periodate, and sodium borate. The fluore...

Experiments were conducted on an AZ61 magnesium alloy to evaluate the microstructural characteristics and the mechanical properties after processing by High-Pressure Torsion (HPT). The results show that processing by HPT produces excellent grain refinement with average grain sizes of similar to 0.22 and similar to 0.11 mu m after processing at 423...

Auf das „Image“ kommt es an: Makromolekulare Verbindungen aus Dextran, Luminol und Biotin dienen als nichtenzymatische Sonden für die empfindliche Chemilumineszenz(CL)-Bildgebung von Cytochrom P450 (CYP) an einer Poly(vinylidendifluorid)(PVDF)-Membran (siehe Bild). Die polymere Gerüststruktur wurde einfach durch Mischen der Sonde mit Avidin im Verh...

The chemiluminescence of a luminol-H(2)O(2) system is found to be remarkably enhanced by the Ce(IV) complexes of EDTA-bridged cyclodextrin dimers. The dimers were proved to work much more efficiently than the corresponding monomer. The cavity shape of cyclodextrin moieties and their cooperation displayed an important role in amplifying the chemilum...

A simple, rapid, and sensitive method for the assay of a sequence-specific DNA-binding protein, nuclear factor-kappaB (NF-kappaB), has been developed by using a DNA-detectable chemiluminogenic reagent and a centrifugal filter that distinguishes different molecular sizes. After the formation of a complex between NF-kappaB and DNA, the unbound DNA is...

A magnesium alloy AZ61 was subjected to a process of severe plastic deformation through high pressure torsion (HPT) at room and elevated temperatures. For the HPT process, a pressure of 3 GPa was applied to the alloy with a disk-shaped sample having dimensions of 10 mm in diameter and 0.8 mm in thickness while the lower anvil was rotated with respe...

The 4-(1′-cyanoisoindolyl)phenylisothiocyanate (CIPIC) could be used as a chemiluminescence (CL) Edman-type reagent. Firstly, CL reaction conditions such as pH, buffer types, H2O2 concentration and organic solvents were optimized in detail. Secondly, the CL sensitivity of the derivative of Ala was compared with fluorescence and absorbance detection...

The label-free DNA sensing techniques are currently receiving considerable attention for the determination of pathogenic genes and the diagnosis of genetic disease, etc. Based on magnetic separation and preconcentration, a novel label-free chemiluminescence (CL) detection protocol was presented as exemplified by the successful determination of spec...

The inhibitory effects of (1R,9S)- and (1S,9R)-enantiomers of beta-hydrastine (BHS) on dopamine biosynthesis in PC12 cells were investigated. (1R,9S)-BHS decreased the intracellular dopamine content with the IC50 value of 14.3 microM at 24 h, but (1S,9R)-BHS did not. (1R,9S)-BHS was not cytotoxic at concentrations up to 250 microM towards PC12 cell...

(1R,9S)-beta-Hydrastine in lower concentrations of 10-50 microM inhibits dopamine biosynthesis in PC12 cells. In this study, the effects of (1R,9S)-beta-hydrastine on L-DOPA (L-3,4-dihydroxyphenylalanine)-induced cytotoxicity in PC12 cells were investigated. (1R,9S)-Hydrastine at concentrations up to 250 microM did not reduce cell viability. Howeve...

Here we report a rather simple and convenient chemiluminescence (CL) method for the determination of tetracycline (TC). It is based on the observation that tetracycline can greatly enhance an ultra-weak CL between H2O2 and acetonitrile in a basic alkaline solution. Light emission is intense and long-lived, and even with a simple set-up, a high sens...

For the first time we report on the detection of telomeres by coupling of the label-free guanine CL detection route with an efficient magnetic isolation of the hybrid.

Here we report a rather simple and convenient chemiluminescence (CL) method for the determination of tiopronin. It was based that tiopronin could greatly enhance CL between H2O2 and luminol in a basic alkaline solution. Light emission is intense, and even with a simple setup a high sensitivity could be achieved. The linear range was 3 mM-500 nM wit...

We report analytical informations on the quantification of cefaclor (CCL), a beta-lactam antibiotic by three detection methods. The methods were based on the chemical derivatization of the drug with 4-(2'-cyanoisoindolyl)phenylisothiocyanate (CIPIC) under the reaction conditions with heating at 80 degrees C for 7 min in the presence of pyridine. Th...

We present a sensitive method for the determination of cefaclor (CCL), a beta-lactam antibiotic. It was based on the chemical derivatization of the drug with 4-(2'-cyanoisoindolyl)phenylisothiocynate (CIPIC) under the reaction conditions with heating at 80 degrees C for 7 min in the presence of pyridine. The CIPIC reagent could react with the prima...

A robust and sensitive non-enzymatic chemiluminescence (CL) imaging method is presented. In the method a fast-emitting CL reaction is tuned to furnish a slower-emitting reaction suitable for simple CL imaging. Typically, non-enzymatic CL reactions between luminol or fluorescein and oxygen species generated by KCN as catalyst, were rather fast and u...

The chemiluminescence of the luminol-H2O2 system is found for the first time to be remarkably enhanced by the Ce(IV) complexes of cyclodextrin dimers.

A simple and convenient chemiluminescence (CL) method for the determination of melatonin is reported. It is based on the observation that melatonin can greatly enhance the ultra-weak CL between H2O2 and acetonitrile in alkaline solution. Light emission is intense and long-lived, and even with a simple setup, a high sensitivity could be achieved. Th...

Here we report a new chemiluminescence reaction between basic aqueous H2O2 and acetonitrile. Its ultraweak chemiluminescence could be greatly enhanced by luminol, isoluminol-labeled streptavidin, and an Edman-type fluorescent reagent. Light emission was intense and long-lived, and this facilitated the initiation of the reaction and the measurement...

The effects of hydrastine derivatives on dopamine biosynthesis in PC12 cells were investigated. Treatments of PC12 cells with (1R,9S)-beta-hydrastine hydrochloride [(+)-beta-hydrastine HCl] and (1R,9S)-beta-hydrastine [(-)-beta-hydrastine] showed 50.6 % and 33.1 % inhibition of dopamine content at a concentration of 10 microM for 48 h. However, (1S...

A selective and highly sensitive liquid chromatographic method for the determination of ganciclovir (anti-virus drug) in human serum was described. After ganciclovir and acyclovir (internal standard; IS) were extracted with solid-phase extraction cartridge from serum, they were converted into fluorescent derivatives by reaction with phenylglyoxal i...

The effects of benzophenanthridine alkaloids, such as sanguinarine and chelidonine, on monoamine -oxidase (MAO) activity in mouse brain were investigated. Sanguinarine showed an inhibitory effect on MAO activity in a concentration dependent manner (53.4% inhibition at 25 microM). However, chelidonine did not inhibit MAO activity. The IC(50) value o...

A selective and sensitive HPLC measurement of 3′,5′-cyclic nucleotide phosphodiesterase (PDE; EC 3.1.4.17) activity in rat cerebral cortex is described using (3,4-dimethoxyphenyl)glyoxal (DMPG) as a fluorogenic reagent for guanine and its nucleosides and nucleotides. cGMP, a substrate of PDE, and GMP, which was produced by the enzyme reaction, are...

Berberine and palmatine exhibit a mild and competitive inhibition on bovine adrenal tyrosine hydroxylase (EC 1.14.16.2; TH). In this study, the inhibitory effects of protoberberine alkaloids (such as berberine, palmatine and coptisine) on dopamine biosynthesis in PC12 cells were investigated. Treatment with berberine and palmatine showed 53.7% and...

We have investigated the effects of natural isoquinoline alkaloids on monoamine oxidase (EC 1.4.3.4; MAO) activity in mouse brain. The protoberberine alkaloids berberine and palmatine showed inhibitory effects on MAO activity. However, two bisbenzylisoquinoline alkaloids, as tetrandrine and fangchinoline; two phthalide-isoquinoline alkaloids, nosca...

A chemiluminescence derivatization method using a novel reagent, 3′,4′,5′-trimethoxyphenylglyoxal (TMPG) was studied for the quantitative detection of nucleic acids and deoxyguanylic acid oligomers on a nylon membrane. In the method, TMPG rapidly converted guanine of a nucleic acid to a chemiluminescent derivative in an alkaline phosphate solution...

A pre-column derivatization method using a fluorogenic reagent, 1,2-diphenylethylenediamine (DPE) was studied for the sensitive HPLC determination of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA), which are biosubstances used in the diagnosis of several diseases. For the quantitative determination, the biogenic indole compounds...

3,4-Dimethoxyphenylglyoxal was found to react sensitively and selectively with guanine-containing compounds to yield their fluorescent derivatives. This reaction and postcolumn fluorescence derivatization liquid chromatography were used to determine the production of 7-methylguanine and O6-methylguanine in DNA after alkylation with N-methyl-N-nitro...

Many opioid peptides having N-terminal tyrosyl residue of their amino acid sequence occur at low concentrations in mammalian brain tissues and body fluids. Their endogenous concentrations are controlled by synthetic and metabolic enzymes. It is therefore of great importance to develop an analytical protocol that permits facile and sensitive determi...

A sensitive and selective method for the determination of guanosine 3',5'-cyclic monophosphate in human urine is described. The method uses high-performance liquid chromatography with fluorescence detection. Guanosine 3',5'-cyclic monophosphate and other guanine nucleotides in human urine, after a clean-up with an anion exchanger cartridge (TOYOPAK...

Two HPLC procedures based on sample derivatization at the N-terminal Tyr moiety with agents yielding fluorescent derivatives were applied to the selective and sensitive detection as well as quantification of the basic kyotorphin, Tyr-Arg dipeptide, in rat brain tissue. The first one is a post-column fluorescence derivatization method, whereby the p...

Novel chemiluminogenic reaction is described for the sensitive determination of Arg-containing peptides. The reaction is based on fluorescence derivatization of the peptides with benzoin in a potassium hydroxide solution at 100 degrees C for 2 min, followed by chemiluminescence reaction with an aprotic polar solvent(N,N-dimethylformamide, dimethyl...

Chemiluminescence detection in high-performance liquid chromatography for derivatives of catecholamines (norepinephrine, epinephrine and dopamine) and isoproterenol was studied on the basis of the peroxyoxalate chemiluminescence reaction. The amines and isoproterenol, derivatized with 1,2-diarylethylenediamines, were separated on a reversed-phase H...

We have measured arginine vasopressin in the neural lobe, the trigeminal ganglion (TG), dorsal root ganglia (DRG), spinal cord, trigeminal and sciatic nerves of the rat by radioimmunoassay. In control rats, the neural lobe contained 1600 pg/mg, the ganglia 52.5, 21.0, 8.5, 4.28, 3.85 pg/mg in the lumbar, sacral, cervical, thoracic, and trigeminal g...

A chemiluminescence detection of the fluorescent derivatives of catecholamines (norepinephrine, epinephrine and dopamine) and isoproterenol as an internal standard is described for the highly sensitive liquid Chromatographic determination of these compounds. The amines were converted by reaction with 1,2-diphenylethylenediamine into the correspondi...

A number of fluorogenic reactions, which have been used for HPLC detection systems by means of pre- and/or postcolumn derivatization, are surveyed with respect to both sensitivity and selectivity for the determination of biomedically important substances. For the derivatization of the substances, two types of fluorogenic reactions, fluorescence-gen...

A newly synthesized Edman-type fluorogenic reagent, 4-(2-cyanoisoindolyl)phenylisothiocyanate, reacted with 20 tested amino acids in a basic medium to produce the corresponding thiocarbamoyl derivatives. The derivatives were converted in an acidic medium to the thiohydantoin derivatives which were separated by reversed-phase chromatography and dete...

A high-performance liquid chromatographic method with on-line postcolumn fluorescence derivatization is described for the simple and sensitive determination of guanine and its nucleosides and nucleotides in human erythrocytes. After deproteinization of the biospecimen, guanine and its nucleosides and nucleotides were separated on a reversed-phase c...

A fluorometric method based on the measurement of two nucleobase pairs of guanine-cytosine and adenine-thymine was developed for the accurate quantification of double-stranded DNA. Two fluorescence reactions with phenylglyoxal and chloroacetaldehyde are utilized for detection of the guanine and adenine moieties in DNA, respectively. The optimized c...

High-performance liquid chromatographic determination of guanine and its nucleosides and nucleotides in rat brain tissue and human erythocytes has been accomplished by means of a precolumn fluorescence derivatization method. These compounds in deproteinized samples were selectively converted with phenylglyoxal to fluorescent derivatives. The deriva...