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Biomedical subjects

K Uchiyama

Publications and source records attributed to K Uchiyama.

At least 37 records · Page 2Linked to original sources
PubMed2001

On-chip integration of sequential ion-sensing system based on intermittent reagent pumping and formation of two-layer flow.

A sequential ion-sensing system using a single microchip was successfully realized. The system developed here involves intermittent pumping of plural organic phases into a microchannel, followed by contact with a single aqueous phase to form a stable organic-aqueous two-layer flow inside the microchannel. Because the plural organic phases created by intermittent flow contain the same lipophilic pH indicator dye but different ion-selective neutral ionophores, different ions can be sequentially and selectively extracted into the different organic phases, where they can be determined by thermal lens microscopy (TLM). We used KD-A3 as the lipophilic pH indicator dye and valinomycin and DD16C5 as neutral ionophores to demonstrate sequential ion sensing of potassium and sodium ions by measuring the deprotonated dye caused by the ion extraction. The integrated microfluidic system proposed here allows multi-ion sensing, which is not easily demonstrated by conventional ion sensor technology using a solvent polymeric membrane. The minimum volume of single organic phase needed to obtain an equilibrium response without dilution by cross dispersion of two organic phases was ca. 500 nL in our system, indicating that the required amounts of expensive reagents in one measurement could be reduced to 1.7 ng and 2.8 ng for the dye and ionophore molecules, respectively.

Biosensing Techniques↗
PubMed2001

Effect of sodium tauroursodeoxycholate on phalloidin-induced cholestasis in rats.

We investigated the therapeutic effect of tauroursodeoxycholate on phalloidin-induced cholestasis in rats. Intrahepatic cholestasis was induced by administration of phalloidin (500 microg/kg, i.p.) for 7 days. From the day of the last phalloidin injection, tauroursodeoxycholate (60-360 micromol/kg) was given intravenously twice a day for 4 days. On the next day after the last tauroursodeoxycholate administration, bile flow, serum biochemical parameters and biliary lipid excretion rates were determined. Tauroursodeoxycholate significantly suppressed the decrease in bile flow and increases in serum alkaline phosphatase, leucine aminopeptidase and glutamic pyruvic transaminase activities, cholesterol, phospholipid and bile acid concentrations observed in phalloidin-induced cholestasis in rats. Furthermore, tauroursodeoxycholate significantly improved the biliary cholesterol and phospholipid excretion rates in phalloidin-induced cholestasis in rats. These results demonstrate the usefulness of tauroursodeoxycholate as a therapeutic agent in intrahepatic cholestasis.

Alanine Transaminase↗
PubMed2001

Continuous preconcentration system for nitrate ions using anionic reverse osmosis tubes coupled to an ion chromatograph.

A continuous preconcentration system for nitrate ions was developed using cation exchange tubing made from Nafion perfluorosulfonic acid membrane. This method is based on ion exclusion effects and reverse osmosis phenomena. The system was evaluated by connecting it to an ion chromatograph. The concentration ratios could be increased by raising the pressures between the two sides of the cation exchange tubing. Twenty-fold concentration of nitrate ion was achieved when the pump pressure was 20 x 10(5) Pa. The relative standard deviations of the preconcentration ratio at four different pump pressures, 5, 10, 15 and 20 x 10(5) Pa were 1.2-2.8% (n = 5).

Journal Article↗
PubMed2001

Fabrication of polyester microchannels and their applications to capillary electrophoresis.

Inexpensive and disposable polyester microchips were fabricated through photolithographic and wet-chemical etching procedure, followed by replication using an imprinting method at room temperature. Laboratory-scale laser-induced fluorescence equipment was employed as a detection system. The generation of electroosmotic flow (EOF) on the polyester channels was discussed in this paper. Surfactants in the running buffer had a significant effect on the EOF depending on their types. The epsilon potential of the electric double layer formed by adsorbing sodium lauryl sulfate molecules on the wall of polyester channels seemed to be constant within the buffer pH investigated. EOF could also be suppressed to zero by adding polyoxyethylene 23 lauryl ether into the running buffer. The separation of two laser dyes was obtained using polyester chips through both micellar electrokinetic chromatography and capillary zone electrophoresis. The polyester channels modified with 10-undecen-1-ol exhibited a dramatically high-separation efficiency compared with the conventional fused-silica capillary tubes.

Electrophoresis, Capillary↗
PubMed2001

Interaction between 18-crown-6-tetracarboxylic acid and positional substituents of enantiomers and simultaneous separation of positional enantiomers of methyl-DL-tryptophans by capillary electrophoresis.

18-Crown-6-tetracarboxylic acid (18C6H4) is a chiral selector with high selectivity for the enantioseparation of solutes bearing the primary amine function. This work presents the simultaneous separation of positional enantiomers of methyl-DL-tryptophans by using 18C6H4 as an additive to the background electrolyte. Separation conditions such as pH, the concentration of 18C6H4, and the applied voltages have critical inference on the simultaneous separation. The addition of cyclodextrins as anionic surfactants to the background electrolyte did not improve the separation. The selector-selectand interactions between 18C6H4 and the positional enantiomers have been investigated. It was observed that both the position and type of substituents contribute to the enantioselectivity. The migration order and resolution depended on the distance from the substituents to the asymmetric carbon of the enantiomers.

Crown Ethers↗
PubMed2001

Detectability of pulmonary perfusion defect and influence of breath holding on contrast-enhanced thick-slice 2D and on 3D MR pulmonary perfusion images.

The present study assesses the detectability of perfusion defect and the influence of breathhold on pulmonary magnetic resonance (MR) perfusion imaging using contrast-enhanced thick-slice two-dimensional (2D) fast gradient-echo sequence compared with three-dimensional (3D) fast spoiled gradient-recalled sequence. Dynamic studies were performed in 16 patients. MR perfusion images were interpreted by two independent observers using perfusion scintigraphy as the reference standard. The patients were divided into two groups according to the duration of holding the breath measured during MR imaging. The sensitivity and specificity of 2D MR perfusion imaging in detecting perfusion defects were 93% and 94%, respectively, while those of 3D MR perfusion imaging were 89% and 85%, respectively. The diagnostic accuracy of 2D MR perfusion imaging was significantly higher than that of 3D MR perfusion imaging (P < 0.05) among those who could not hold their breath. Therefore, 2D MR perfusion imaging offers promise for evaluating pulmonary perfusion even among patients who cannot hold their breath.

Adult↗
PubMed2001

Positivity of extrapulmonary Ga-67 uptake in sarcoidosis: thyroid uptake due to chronic thyroiditis and bone uptake due to fibrous dysplasia.

Ga-67 citrate scintigraphy was performed on a 29-year-old man who had been diagnosed as having pulmonary sarcoidosis by a transbronchial lung biopsy. A Ga-67 citrate scintigram showed increased uptake not only in the pulmonary hilum and mediastinum, but also in the thyroid gland and the right ilium. Chronic thyroiditis was confirmed by aspiration biopsy of the thyroid gland, and fibrous dysplasia was confirmed by CT guided biopsy of the right ilium. Extrapulmonary Ga-67 uptake in patients with sarcoidosis does not necessarily indicate the involvement of other tissues and organs.

Adult↗
PubMed2001

Unusual early bile excretion from the liver in patients with fulminant hepatic failure as detected by Tc-99m-PMT hepatobiliary scintigraphy; comparison with Tc-99m-GSA scintigraphy.

In two females (58 and 14 years old) with fulminant hepatic failure, Tc-99m-PMT hepatobiliary scintigraphy was used to evaluate intrahepatic bile stagnation, and Tc-99m-GSA scintigraphy to evaluate hepatic functional reserve. In both patients, Tc-99m-PMT hepatobiliary scintigraphy showed unusual early bile excretion into the extrahepatic bile duct and small intestine within the first 30 min of imaging. These findings contradicted typical findings of intrahepatic bile stagnation of fulminant hepatic failure. The receptor index and blood clearance index determined from dynamic acquisition data on Tc-99m-GSA scintigraphy suggested a markedly decreased hepatic functional reserve. These findings were compatible with fulminant hepatic failure. A discrepancy was observed between the findings of hepatobiliary scintigraphy and those of Tc-99m-GSA scintigraphy. The pathological state of early bile excretion from the liver into the bile duct should be considered in fulminant hepatic failure.

Adolescent↗
PubMed2001

Polyester microchannel chip for electrophoresis--incorporation of a blue LED as light source.

A blue-light-emitting diode was incorporated as a fluorescence-excitation light source into a polyester microchannel chip fabricated by in situ polymerization. Placing the light-emitting facet of the diode close to the microchannel obviated any need for an additional optical arrangement. Fluorescence from the sample was transmitted by an optical fiber incorporated into the microchip perpendicular to the LED. FITC labeled amino acids were separated in the presence of 5 mM SDS by using the microchip and were detected by LED-induced fluorescence.

Amino Acids↗
PubMed2001

Expression of JNK cascade scaffold protein JSAP1 in the mouse nervous system.

The mitogen-activated protein kinase (MAPK) cascades consist of MAPK, MAPK kinase (MAPKK), and MAPKK kinase (MAPKKK). The specificity of activation of MAPK cascades may be determined, in part, by scaffold proteins that organize multi-enzyme complexes. We have earlier reported a scaffold protein JSAP1 (also known as JIP3) in the JNK MAPK cascade. We also showed that, of the adult mouse tissues tested, JSAP1 mRNA was predominantly expressed in brain. Here we report the localization of JSAP1 protein in mouse embryos and adult brain by immunohistochemical analysis. In embryos (E11-16), JSAP1 immunoreactivity was mainly found in the central and peripheral nervous systems, where it was localized to the cell bodies and/or axons of developing neurons, but not neural precursor cells. In the adult brain, immunoreactive JSAP1 was localized mostly to cell bodies in almost all neurons. We also showed that the expression of JSAP1 transcripts and proteins gradually increased during the neural differentiation of mouse P19 embryonal carcinoma (EC) cells. Furthermore, we showed that overexpressed JSAP1 facilitated the efficient activation of JNK by MEKK1 in P19 cells. These results suggest that JSAP1 may function as a scaffold protein for the JNK signaling module in neuronal cells.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Deep circumflex iliac perforator flap with iliac crest for mandibular reconstruction.

The deep circumflex iliac myocutaneous perforator (DCIP) flap with iliac crest was used to reconstruct oromandibular defects in 10 patients. In seven of the patients a dominant perforator was found preoperatively using a Doppler flowmeter; in five of these seven patients a DCIP flap was successfully transferred. In two of the seven patients the dominant perforators were too narrow: one patient underwent a standard osteocutaneous flap transfer and one patient underwent a second flap transfer. In three patients no dominant perforator was found before or during surgery. The freedom of the DCIP flap from the harvested iliac crest facilitates correct positioning. However, to ensure that the DCIP flap can be safely elevated, the presence of perforators must be confirmed preoperatively. Even when a perforator has been identified, complicated dissection may be necessary. We stress the importance of a thorough knowledge of the anatomy of second flaps and of obtaining informed consent to use them.

Adult↗
PubMed2001

Characterization of bacteriocin N15 produced by Enterococcus faecium N15 and cloning of the related genes.

Enterococcus faecium N15 was isolated from nuka (Japanese rice-bran paste), which is utilized as starter in the fermenting of vegetables, and was found to produce a bacteriocin that exhibited a broad spectrum of activity, including activity against Listeria monocytogenes and Bacillus circulans JCM2504. The bacteriocin was sensitive to proteases (alpha-chymotrypsin, proteinase K, trypsin, and pepsin) and alpha-amylase, but it was resistant to lipase. The bacteriocin was resistant to heat treatment at 100 degrees C for 2 h, but its activity was completely lost after autoclaving at 121 degrees C for 15 min. It was active over a wide pH range from 2.0 to 10.0. The bacteriocin showed bactericidal activity against Lactobacillus sake JCM1157 at a concentration of 40 AU/ml. Its molecular weight was estimated by SDS-PAGE to be about 3-5 kDa. PCR primers were designed based on the conserved amino acid sequences of class IIa bacteriocins. A 3-kb DNA fragment was amplified and three open reading frames (ORFs) were found. The first encodes a probable immunity protein of 103 amino acid residues and shows complete homology with the putative immunity protein of E. faecium DPC1146. The second and third ORFs respectively encode a probable transposase gene and an inducing factor. The upstream region of the immunity gene, in which the bacteriocin structural gene is located, was amplified. A homology search revealed that the bacteriocin produced by E. faecium N15 exhibits complete identity to enterocin A, a bacteriocin produced by E. faecium DPC1146. PCR using the primers designed in this study is a rapid and sufficient method of screening for bacteriocin-producing strains.

Journal Article↗
PubMed2001

Adenosquamous carcinoma of the pancreas: successful treatment with extended radical surgery, intraoperative radiation therapy, and locoregional chemotherapy.

BACKGROUND: Adenosquamous carcinoma of the pancreas is a rare tumor with an extremely poor survival rate. No obvious evidence that multidisciplinary treatments improves the prognosis and survival has been reported. PATIENT AND RESULTS: A 63-yr-old female with adenosquamous carcinoma of the pancreas underwent extended radical surgery, intraoperative radiation therapy, postoperative intraarterial chemotherapy, and external beam radiation therapy. The patient is alive at 40 mo after surgery with no recurrence. CONCLUSIONS: Multidisciplinary treatments including aggressive surgery, intraoperative radiation therapy, and locoregional chemotherapy might improve the survival of patients with adenosquamous carcinoma of the pancreas to inhibit liver metastasis and local recurrence.

Antineoplastic Agents↗
PubMed2001

Photo-responsive retention behavior of azobenzene-modified cyclodextrin stationary phase in micro-HPLC.

An azobenzene-modified gamma-cyclodextrin stationary phase (Az gamma-CDSP) was prepared and its photo- and temperature-responses for the retention of perylene and pentacene were investigated using a mixture of methanol and water as the mobile phase in micro-HPLC. The retention of perylene slightly increased, whereas that of pentacene significantly decreased by UV light irradiation to Az gamma-CDSP. These retentions recovered upon irradiation with visible light. Both retentions decreased upon an increase in the column temperature. It was presumed that the trans-azobenzene moiety acts as a preventive cap for perylene and a spacing for pentacene in filling the CD cavity. An azobenzene-modified stationary phase changed its retention behavior with the column temperature and the light irradiation. An improvement in the micro-HPLC system and the optimization of the molecular structure of the photo-responsive stationary phase would provide selective retention control by the irradiation of light in micro-separation systems.

Azo Compounds↗
PubMed2001

Integrated multilayer flow system on a microchip.

We utilized microchip technology and found that the multilayer flow of liquids can be formed in microchannels. Liquid/liquid interfaces were formed parallel to the side wall of the microchannels, because the surface tension and friction force are stronger than the force of gravity. A water/ethylacetate/water interface was formed in a 70-microm-wide and 30-microm-deep channel. The interface was observed to be quite stable and to be maintained for a distance of more than 18 cm. As an example of a multilayer flow application, we demonstrated the liquid/liquid extraction of Co-dimethylaminophenol complex in a microchannel. The solvent-extraction process of the complex into m-xylene in the multilayer flow was found to reach equilibrium in 4 s, while it took 60 s in a simple two-phase extraction.

Journal Article↗
PubMed2001

Validity and reliability of the Japanese version of the Emotional Intelligence Scale among college students and psychiatric outpatients.

We examined the validity and reliability of the Japanese version of the Emotional Intelligence Scale in two samples of 267 college students and 398 psychiatric outpatients. Suitable validity and reliability of this scale were suggested by high correlations with scores on the NEO Personality Inventory, adequate internal consistency, and relatively high test-retest correlations. The Emotional Intelligence Scale seems suitable for both clinically distressed populations as well as comparative groups such as college students.

Adaptation, Psychological↗
PubMed2001

Association of emotional intelligence with alexithymic characteristics.

We examined the association of emotional intelligence and alexithymic characteristics as the personality trait in cohorts of 267 college students and 398 psychiatric outpatients. Score on the Toronto Alexithymia Scale were significantly correlated with those on the Emotional Intelligence Scale, suggesting that alexithymic characteristics are related to lower emotional intelligence. In conclusion, these data suggest that emotional intelligence overlaps with alexithymia.

Adaptation, Psychological↗