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Biomedical subjects

Takao Tsuda

Publications and source records attributed to Takao Tsuda.

13 recordsLinked to original sources
PubMed2005

Preparation of red blood cell column for capillary electrochromatography.

A column packed with red blood cells (RBCs) was prepared for electrochromatography as a separation and reaction column. RBCs were kept inside a piece of fused silica capillary tubing with 2% agarose gel. In the column, RBCs were uniformly distributed in the agarose gel matrix and their electrophoretic movements due to an applied voltage were suppressed well. The durability of the biological function of the column under applied voltage was about 1 h, although it could remain for 2-3 days without applied voltage. The column could not be used when hemolysis of the RBCs was observed in the column. When the developed "RBC-gel column" was used, both pyridoxamine and serotonin were converted to other compounds through their direct contact with RBCs.

Electrophoresis, Capillary↗
PubMed2005

Identification of gas emanated from human skin: methane, ethylene, and ethane.

We investigated whether methane, ethylene and ethane gas can be detected in gas emanating from human skin, which is called skin gas. Skin gas was collected with a homemade stainless-steel trap system, which was cooled with liquid nitrogen, and analyzed with a gas chromatograph fitted with a flame ionization detector (FID). Skin-gas samples were obtained by covering a hand for 30 min with a polyfluorovinyl bag in which pure helium gas was introduced. The bag, the trap system and GC were set up online to avoid any contamination by air. Methane, ethylene and ethane in skin gas were successfully collected at an average amount emanated for 30 min (from ten subjects) of 150 +/- 63, 20 +/- 11 and 17 +/- 8 [mean +/- SD] pg/cm2, respectively.

Adult↗
PubMed2004

Study of flow rate in pressurized gradient capillary electrochromatography using splitter and separation of peptides using an Amide stationary phase.

A pressurized gradient capillary electrochromatograph using a splitter was constructed. The variation in flow rate during gradient elution was investigated and separations of peptides using an Amide stationary phase were demonstrated. The flow rate, which is one of the important factors to control chromatographic behavior, was increased during the gradient elution, and the mismatching of mobile phase between the column and the resistance tubing derived three variation patterns in the flow rate. The electrophoretic migration in electrochromatography could enhance in separation of peptides. The separated peak number of tryptic digest of bovine serum albumin was increased from 30 to 40 by the application of +5 kV.

Amides↗
PubMed2004

Effect of pressure on electrophoretic mobility of polystyrene latex particles.

A capillary electrophoresis system that can apply arbitrary helium gas pressures at both inlet and outlet reservoirs was constructed. The system was used to investigate the effect of pressure on electrophoretic behavior of polystyrene latex particles. The electrophoretic mobility of latex particles was increased with the application of pressure (< 3.0 kgf/cm2). The shrinkage of particle diameter under pressurization was observed using a microscope, however, the magnitude of shrinkage was not enough to explain the increase in electrophoretic mobility. Therefore, the application of pressure might increase the electric charge of the latex particle. Since methanol inhibited the enhancement in the electrophoretic mobility of the latex particles, water might play an important role in increasing mobility.

Electrophoresis, Capillary↗
PubMed2004

A finger sweat chloride test for the detection of a high-risk group of chronic pancreatitis.

OBJECTIVES: Mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene are associated with chronic pancreatitis in Caucasians. We developed a simple method for measuring finger sweat chloride concentration to test whether CFTR dysfunction underlies chronic pancreatitis in Japan where cystic fibrosis (CF) is rare. METHODS: We studied 25 patients with chronic (21 alcoholic and 4 idiopathic) pancreatitis and 25 healthy volunteers. Sweat chloride concentrations were measured by a finger sweat chloride test. We analyzed DNA for 20 common CFTR mutations in Europeans, 9 CF-causing mutations in Japanese, and 2 polymorphic loci, a poly-T tract and (TG) repeats, at intron 8. RESULTS: Thirteen patients (52%) had sweat chloride levels >60 mmol/L, a level consistent with CF, while only 4 (16%) healthy subjects exceeded this level. The 29 CF mutations and the 5T allele were detected in neither the patients nor controls. The (TG) 12 allele was common in both the patients (58%) and controls (48%). The (TG) 12/12 genotype was common in alcoholic pancreatitis (29%) compared with the (TG) 11/11 (10%). Patients with the (TG) 12/12 genotype had significantly higher sweat chloride concentrations than the controls. CONCLUSION: CFTR dysfunction as evidenced by a finger sweat chloride test is present in about half of Japanese patients with chronic pancreatitis, suggesting that this test may be useful for detecting the high-risk group. A higher proportion of the (TG) 12 allele may be a genetic background for elevated sweat chloride concentrations in Japanese patients.

Adult↗
PubMed2004

Preparation of a new type of fiber adsorbent attached with silica microparticles.

A new type of fiber adsorbent attached with silica microparticles was prepared. The silica microparticles were formed by the polymerization of silica oligomers on glass fibers, which were woven into a glass filter. The surface of the silica microparticles was chemically modified by bonding C18-ligands. SEM images indicated that the diameter of the uniform and spherical silica microparticles fixed on glass fibers was on the order of micrometers. It was confirmed that the glass filter adsorbent was effective for the adsorptive removal of toluene of low concentrations.

Journal Article↗
PubMed2003

Nanoinjector for capillary electrophoresis and capillary electrochromatography.

A rotary valve nanoinjector was devised for use in capillary electrophoresis (CE) and capillary electrochromatography (CEC). A fused-silica capillary tip was inserted in a small through-hole in the rotor. The narrow and short capillary tip, with an inner volume of 6-24 nL, was embedded in the hole using epoxy resin. The injection volume was confirmed chromatographically by comparing the peak areas obtained with the nanoinjector to those of a conventional injector. In addition, both the rotor and stator of the injector were made of a nonconducting material, polyimide resin, to be utilized for CE and CEC. The application of the nanoinjector for CE was demonstrated.

Journal Article↗
PubMed2003

Alternating voltage capillary electrochromatography.

A phenomenon was found whereby the application of an alternating voltage to a capillary column can vary the capacity factor of a sample solute. The alternating voltage-induced variation in the capacity factor was studied using an anion exchange mini-bed (a short capillary column 12 mm long). The capacity factor varied according to both the amplitude and frequency of an applied alternating voltage. The variation greatly depended on the kinds of sample solutes and packing materials. A new separation mode for capillary electrochromatography using an alternating voltage, that is, alternating voltage capillary electrochromatography (AV-CEC), was proposed as an application of this phenomenon to control the retention of a sample solute. The chromatographic behavior of three organic acids (benzoic acid, phthalic acid, and salicylic acid) was studied in AV-CEC using an anion exchange column.

Journal Article↗
PubMed2003

Behavior of neutral solutes in pressurized flow driven electrochromatography using a mixed stationary phase of ODS and anion-exchange.

The behavior of neutral sample solutes in pressurized flow driven electrochromatography using a mixed stationary phase, which consisted of ODS and anion-exchange (ODS-SAX), was studied. Applications of both positive and negative voltage on a column induced increases in retention factors of sample solutes. The direction of an electroosmotic flow under applications of positive and negative voltage were the same, therefore, the sign of the surface charge density under positive and negative voltage was opposite. We proposed a new equation for the relationship between applied voltage and surface charge density, and the practical electroosmotic flow conformed to this equation. Studying the electroosmotic flow using our proposed equation revealed that the applied negative voltage accelerates the protonation of the quaternary ammonium group and dissociation of the silanol group on packing materials. The retention behavior of a neutral solute was affected by the existence of the charged functional groups. We propose that this phenomenon is applicable to the control of the retention behavior of a sample solute using an electric field.

Chromatography, Ion Exchange↗
PubMed2002

Estimation of electrophoretic mobilities of red blood cells in 1-G and microgravity using a miniature capillary electrophoresis unit.

Electrophoretic mobilities of red blood cells (RBCs) were measured in microgravity using a home-made capillary electrophoresis unit, which consisted of two small reservoirs of 0.6 mL and a fused-silica capillary tubing with 2 cm in length and 50 num in inner diameter. Migration of RBCs was observed by a microscope at 1000 times magnification and recorded on a videotape. The experiments were performed during stays in microgravity (about 0.01 G), which lasted 20 s and were attained by parabolic flights of an aircraft. On average, the electrophoretic mobilities of RBCs determined in microgravity were about 30% higher than those measured at 1-G condition irrespectively whether the cells were suspended in saline or serum during measurements. This difference might be explained as being mainly due to the cell floating in microgravity. Morphological changes of RBCs may contribute partly to the difference, while the variation in viscosity of the medium under microgravity could play only a minor role.

Cell Separation↗
PubMed2002

Exhalation behavior of four organic substrates and water absorbed by human skin.

The simultaneous measurement of several volatile organic compounds and water released from the human skin can be achieved successfully by using a modified gas chromatographic system. After the thumb of each subject was dipped in aqueous solution containing acetone, diethyl ether, ethanol, and toluene, it was dried in the air. Then the thumb attached to the sampling probe for measuring the released gases. It is found that 90% of all these chemical substrates were desorbed after 20 min. The initial exhalation rate factor for each chemical substrate was determined in every subject. Correlation factors of the linear relationships between the initial exhalation rate for hydrophilic substrates (acetone and ethanol) and the total amount of water (TAW) released from the skin were 0.94 and 0.92, respectively. However, the rate of hydrophobic toluene was not dependent on the TAW. Therefore, the exhalation rate of substrates is greatly influenced by both their hydrophilicity and TAW. Additionally, an interesting personal specific character among the 6 subjects was observed on plotting the exhalation rate of organic substrates and water during the elapsed time. With the released water mostly due to insensible perspiration, the exhalation rate of all simultaneous organic substrates decreased monotonically over the elapsed time. On the contrary, when subjects sweated emotionally, the exhalation rate of organic substrates showed some variation, namely a higher of exhalation rate compared to the case of mostly due to insensible perspiration. Therefore, emotionally-induced sweating can enhance the release of organic substrates.

Acetone↗
PubMed2002

Alcohol ingestion stimulates mosquito attraction.

Mosquito bites should be avoided because of the risk of contracting parasitic and viral diseases such as malaria, dengue fever, and several encephalitides. Although humans have been said to suffer more mosquito bites after ingesting liquor, little is known about whether that is true. Thirteen volunteers (12 men from 20 to 58 years old and a 24-year-old woman) were chosen as test hosts and a 30-year-old man was established as a control. We measured ethanol content in sweat, sweat production, and skin temperature before and after ingestion of 350 ml of beer (ethanol concentration 5.5%) by volunteers and compared them with a control subject. Our study demonstrated that percent mosquito landing on volunteers significantly increased after beer ingestion compared with before ingestion, showing clearly that drinking alcohol stimulates mosquito attraction. However, ethanol content in sweat and skin temperature did not show any correlation between alcohol ingestion and mosquito landings. This study shows that persons drinking alcohol should be careful about their increased risk to mosquito bites and therefore exposure to mosquito-borne diseases.

Adult↗