Biomedical subjects

Toshiaki Hattori

Publications and source records attributed to Toshiaki Hattori.

9 recordsLinked to original sources

PubMed2006

Adsorptive voltammetry of 2-(5-bromo-2-pyridyl)azo-5-[N-n-propyl-N-(3-sulfopropyl)amino]phenol on a carbon paste electrode in the presence of organic cations and polycation.

The adsorption of ion-association complexes on a carbon paste electrode (CPE) was investigated by cyclic voltammetry using an electroactive hydrophobic anion probe. The redox reactions of 2-(5-bromo-2-pyridyl)azo-5-[N-n-propyl-N-(3-sulfopropyl)amino]phenol (5-Br-PAPS), the analytical probe, were irreversible. The reduction of the azo group and the oxidation of the phenol were observed at -0.1 V and 0.9 V vs. SCE, respectively, in a 0.1 mol L(-1) H(2)SO(4) solution. The peak currents for the redox reaction increased with the concentration of the cationic surfactant and the accumulation time. The increase in the ratio of the peak current to the concentration of cationic surfactants was proportional to the hydrophobicity. The peak current for 5-Br-PAPS also increased when a polycation, polyhexamethylene biguanide hydrochloride, was added and was strongly dependent on the ionic strength and pH, in contrast to cationic surfactants.

Journal Article↗

PubMed2006

Visual detection of anions by a novel isothiourea-based chromophore.

S-Methyl-N-methyl-N'-(4-(N",N"-dimethylamino)phenyl)isothiourea, a novel isothiourea-based chromoionophore for anions, was synthesized. The reactivity for several anions was estimated by a visual method and UV-vis spectroscopy. By the addition of acetate ion, a blue shift in the absorption spectrum was observed in CHCl3, and the solvent color changed from yellow to colorless. These changes indicated that bound acetate ion interfered with the intramolecular charge transfer from the nitrogen atom of the diethylamino group to the isothiourea moiety. The addition of chloride ion caused a red shift of the chromophore and solvent color remained yellow. By the addition of dihydrogenphosphate ion, the precipitate was formed immediately. These anion-dependent natures of the chromoionophore allowed us to detect acetate and phosphate ions easily.

Acetates↗

PubMed2005

Characterization of polyanion-protein complexes by frontal analysis continuous capillary electrophoresis and small angle neutron scattering: effect of polyanion flexibility.

The binding constant (K(obs)) for the beta-lactoglobulin-poly(vinylsulfate) (BLG-PVS) complex was measured by frontal analysis continuous capillary electrophoresis at pH values above the isoelectric point of BLG, and the persistence length (L(p)) of PVS was measured by small angle neutron scattering, to examine the effect of polyelectrolyte chain stiffness on its binding efficiency to proteins. The values of K(obs) and L(p) were compared with those of BLG-PSS and BLG-PAMPS (poly(2-acrylamido-2-methylpropanesulfonate)) reported previously. The relationship between K(obs) and L(p) was reciprocal, indicating that protein binding is enhanced by the flexibility of the polyanion, at least in the case where the net protein charge is negative. In addition, at a fixed pH, the polymer systems displayed a similar ionic strength dependence of K(obs). This similarity was consistent with the proposal that the binding properties of PVS and PAMPS polyanions are governed purely by electrostatic interactions and are independent of their molecular structure.

Electrophoresis, Capillary↗

PubMed2004

Frontal analysis continuous capillary electrophoresis for protein-polyelectrolyte binding studies.

A novel technique, frontal analysis continuous capillary electrophoresis (FACCE), has been described as an effective way to study protein-polyelectrolyte binding. FACCE involves continuous sampling, integrating sample injection and separation into one process that provides advantages over conventional frontal chromatography. The method provides rapid and precise determination of binding isotherms, and allows for quantitative binding analysis in terms of binding constant and the binding-site size by considering the protein as the ligand and allowing the polyelectrolyte to bind to a number of proteins with variable levels of cooperativity. FACCE is particularly suitable for binding systems involving rapid binding kinetics because it allows for the determination of the concentrations of free or bound ligands under conditions that avoid perturbation of the binding equilibrium. This chapter focuses on studies of the binding of bovine serum albumin (BSA) to heparin using FACCE. These investigations are demonstrated within the context of this chapter as representative of a model protein-polyelectrolyte system from which extensions to other systems can be made.

Animals↗

PubMed2004

Colloidal titration of aqueous zirconium solutions with poly(vinyl sulfate) by potentiometric endpoint detection using a toluidine blue selective electrode.

Zirconium oxy-salts were hydrolyzed to form positively charged polymer or cluster species in acidic solutions. The zirconium hydrolyzed polymer was found to react with a negatively charged polyelectrolyte, such as poly(vinyl sulfate), and to form a stoichiometric polyion complex. Thus, colloidal titration with poly(vinyl sulfate) was applied to measure the zirconium concentration in an acidic solution by using a Toluidine Blue selective plasticized poly(vinyl chloride) membrane electrode as a potentiometric end-point detecting device. The determination could be performed with 1% of the relative standard deviation. The colloidal titration stoichiometry at pH < or = 2 was one mol of zirconium per equivalent mol of poly(vinyl sulfate).

Journal Article↗

PubMed2003

Direct retroperitoneal open drainage via a long posterior oblique incision for infected necrotizing pancreatitis: report of three cases.

Although several surgical approaches have been advocated for patients with infected necrotizing pancreatitis, there is still a high incidence of morbidity and mortality. We used a new approach of direct retroperitoneal open drainage after various other treatments, for three patients with necrotizing pancreatitis and extended infection with multiple-organ failure. Long oblique incisions were made from the root of the 12th rib to the anterior superior spina iliaca on the left or right side of the back, or both, to approach the retroperitoneal area of infected necrosis. The necrotic tissue was removed bluntly and the wound was laid open. Lavage and debridement were done repeatedly after the operation. The patients recovered from multiple-organ failure within 2 weeks, and control of local infection was achieved within 3-4 weeks. All three patients were discharged and are now well. Therefore, we propose that this method is appropriate for patients with spreading infected necroses, who are in poor general condition.

Debridement↗

PubMed2003

Determination of biguanide groups in polyhexamethylene biguanide hydrochloride by titrimetric methods.

The biguanide concentration of polyhexamethylene biguanide hydrochloride (PHMB-HCl) was measured by non-aqueous titration with HClO4, argentometric titration, the Kjeldhal method, and colloidal titration. The summation value of non-aqueous titration and argentometric titration corresponded to two titrable nitrogens in five nitrogens per one unit of PHMB-HCl, and consisted with the result of the Kjeldhal method to the five nitrogens. The colloidal titration of PHMB-HCl at pH 2.05 was equal to that with the two nitrogens. The relative standard deviations of non-aqueous titration, argentometric titration, the Kjeldhal method, and colloidal titration were 0.50% for 8 runs, 0.13% for 7 runs, 3.61% for 6 runs, and 0.69% for 6 runs, respectively.

Biguanides↗

PubMed2002

Electrochemical removal of p-nonylphenol from dilute solutions using a carbon fiber anode.

p-Nonylphenol, which is widely used as raw material in industrial activities has been regarded as an environmental endocrine disrupter. In an effort to develop a new treatment method for p-nonylphenol, we initially investigated the electrochemical behavior of p-nonylphenol by voltammetric techniques. The electrochemical oxidation of p-nonylphenol led to the formation of electropolymerized film on the glassy carbon electrode surface. The fouling on the electrode surface by the electropolymerized film was evaluated by monitoring the electrode response of ferrocyanide ions as the redox marker. The electrochemical removal of p-nonylphenol based on the formation of the electropolymerized film on an anode surface was performed using a carbon fiber (CF) with a very large surface area. The high removal efficiency for p-nonylphenol was obtained by applying a potential at 0.7 V. The maximum surface coverage of electropolymerized p-nonylphenol on the CF was about 5 x 10(-9) mol/cm2. The presence of humic acid hardly inhibited the removal of p-nonylphenol. Furthermore, the application to the removal of phenol, o-chlorophenol, p-chlorophenol, 2,4-dichlorophenol, and 2,4,5-trichlorophenol was attempted by using this method.

Carbon↗

PubMedDate not supplied

Hepatectomy following transarterial chemotherapy for a metastasis in the caudate lobe.

We describe a solitary liver metastasis in the caudate lobe from a colon cancer treated with a hepatic resection following transarterial chemotherapy. A 73-year-old male was admitted with a complaint of melena. The findings from endoscopic examination of the colon showed a type 3 cancer at the hepatic flexure. Computed tomography revealed a metastatic lesion in the caudate lobe of the liver, which was three centimeters in diameter and located between the roots of the middle and the left hepatic vein. A right hemicolectomy was performed and the surgical findings revealed extended lymph node metastasis and the serosal exposure of the primary lesion. A transarterial catheterization to the liver for chemotherapy was placed instead of performing a hepatic resection. After six months of the transarterial chemotherapy, the metastatic tumor was decreased to less than one centimeter and no other new lesion was developed in and out of the liver. The patient underwent a resection of the Spiegel lobe 8 months after the first operation. There were small lesions of viable metastatic cells in the tumor histologically. The patient is currently well without any signs of recurrence 28 months after the first operation.

Aged↗