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Biomedical subjects

A Yagi

Publications and source records attributed to A Yagi.

At least 37 records · Page 2Linked to original sources
PubMed2000

Inhibitory tagging in visual search can be found if search stimuli remain visible.

Klein (1988) reported that inhibitory tagging (i.e., inhibition of return in visual search) made reaction times for the detection of small probes increase at locations where there had previously been rejected items in serial visual search. It is reasonable that the attended and rejected locations are inhibited. However, subsequent studies did not support Klein's idea. In these studies, inhibitory tagging was tested after removing the items from the search tasks. The paradigms in these studies were not appropriate for testing an object-based inhibitory effect because the objects (i.e., items) were removed from the display. In the present study, we found that evidence of inhibitory tagging could be observed only when the items of the search tasks were maintained until the responses for the small probes were made. This appeared to be an object-based effect.

Adolescent↗
PubMed2000

Hydroxyprolylserine derivatives JBP923 and JBP485 exhibit the antihepatitis activities after gastrointestinal absorption in rats.

It has been a desire to develop orally effective therapeutic agents that restore the liver function in chronic injury. Here we demonstrated that trans-4-L-hydroxyprolyl-L-serine (JBP923) and cyclo-trans-4-L-hydroxyprolyl-L-serine (JBP485), which was previously isolated from hydrolysate of human placenta, exhibit potent antihepatitis activity after their oral administration. The increase in bilirubin concentration and activities of liver cytosolic enzymes in serum caused by alpha-naphthylisothiocyanate intoxication in rats were significantly countered both after i.v. and oral administration of these dipeptides, whereas glycyrrhizin, which has been used in the treatment of chronic hepatitis, is active only after its i.v. administration. Antihepatitis activity of dipeptides results, at least partially, from their direct effect on hepatocytes because glutamic-oxaloacetic transaminase and lactate dehydrogenase activities in the medium of hepatotoxin-exposed primary cultured hepatocytes were reduced by these compounds. When comparing the plasma concentration-time profile of JBP923 after its i.v., oral, and portal vein injection, it is suggested that JBP923 is almost completely absorbed from gastrointestinal lumen, and hepatic first-pass removal is minor. JBP923 inhibited the proton-dependent transport of glycylsarcosine in brush-border membrane vesicles, suggesting that peptide transport system(s) may recognize JBP923. Thus, these dipeptides are potent antihepatitis reagents that are still active after oral administration and may be useful for clinical applications.

1-Naphthylisothiocyanate↗
PubMed1999

Transverse elasticity of myofibrils of rabbit skeletal muscle studied by atomic force microscopy.

Surface structure of myofibrils of rabbit skeletal muscle and their transverse elasticity were studied by atomic force microscopy. Images of myofibrils had a periodic structure characteristic of sarcomeres of skeletal muscle fibers. The transverse elasticity distribution in the sarcomere was determined based on force-distance curves measured at various loci of single myofibrils. The Z-line in rigor myofibrils was the most rigid in all the loci of myofibrils studied under various physiological conditions. The overall transverse elasticity of myofibrils decreased in the order in rigor solution > +AMPPNP solution > relaxing solution. The "apparent" transverse Young's modulus of myofibrils estimated at the overlap region between thin and thick filaments was 84.0 +/- 18.1, 37.5 +/- 14.0, and 11.5 +/- 3.5 kPa in rigor, +AMPPNP, and relaxing solution respectively.

Adenylyl Imidodiphosphate↗
PubMed1999

Integrated effect of stimulation at fixation points on EFRP (eye-fixation related brain potentials).

The purpose of this study was to investigate the integrated effect of stimulation at the fixation points just before and just after saccadic eye-movement (saccade) on eye-fixation related brain potentials (EFRP: P75 and N105). Checkerboard patterns were used as stimuli. In Experiment 1, changes in check sizes between two fixation points enhanced the amplitude of P75, while changes in the phases of patterns between the two points did not affect EFRP. This result showed that EFRP was affected by two fixation points, and that changes in the retinal image between the two points did not necessarily affect EFRP. In Experiment 2, the relationship between EFRP and check size was investigated in detail. A second order relationship between logarithm of check size and the latency of P75, and a linear relationship between logarithm of check size and the amplitude of N105 were found. The effect of check size on the amplitude of P75 which might explain the increased amplitude of P75 observed in Experiment 1 did not appear. These results suggest that EFRP might reflect relative higher processing than peripheral stimulation at one fixation point.

Adolescent↗
PubMed1999

Simultaneous high-performance liquid chromatographic determination of puerarin, daidzin, paeoniflorin, liquiritin, cinnamic acid, cinnamaldehyde and glycyrrhizin in Kampo medicines.

We report a high-performance liquid chromatographic method to determine the quantities of puerarin, daidzin, paeoniflorin, liquiritin, cinnamic acid, cinnamaldehyde and glycyrrhizin in Kampo medicine. All seven compounds were separated in less than 30 min with a Wakosil-II 5C18 AR column by linear gradient elution using 0.01% (v/v) phosphoric acid acetonitrile (0 min 90:10, 10 min 88:12, 22 min 70:30, 30 min 30:70) as the mobile phase at a flow-rate of 1.0 ml/min(-1), and detection at 250 nm. The detection limits of these compounds are 0.15-0.3 microM with response linearity. This method was applied to determine the quantities in eight Kampo decoctions; Mao-to, Makyo-yokukan-to, Makyo-kanseki-to, Yokuinin-to, Sho-seiryu-to, Keima-kakuhan-to, Kakkon-to and Kakkon-to-ka-senkyu-sin'i. Glycyrrhizin content was lower in both the decoction and the methanol-diluted decoction of Sho-seiryu-to compared with the others. Low pH due to organic acids of Schisandrae fructus in the decoction caused inhibition for glycyrrhizin dissolution in Sho-seiryu-to.

Acrolein↗
PubMed1999

Simultaneous determination of ephedrine, pseudoephedrine, norephedrine and methylephedrine in Kampo medicines by high-performance liquid chromatography.

A simultaneous high-performance liquid chromatographic method for the determination of ephedrine, pseudoephedrine, norephedrine and methylephedrine (ephedrine alkaloids) in Kampo medicines which contain Ephedrae Herba was established. The analysis can be accomplished within 25 min with a Wakosil-II 5C18 HG column by isocratic elution using a mixture of water, acetonitrile and sodium dodecyl sulfate (65:35:0.4) as the mobile phase at a flow-rate of 1.0 ml min(-1), and detection at 210 nm. The detection limits of ephedrine alkaloids are 0.37-1.06 microM per injection (5 microl). This method was applied to analyze the quantities in eight Kampo decoctions; Mao-to, Makyo-yokukan-to, Makyo-kanseki-to, Yokuinin-to, Sho-seiryu-to, Keima-kakuhan-to, Kakkon-to and Kakkon-to-ka-senkyu-sin'i. The concentration (per Ephedrae Herba gram) of ephedrine alkaloids was higher in the Makyo-kanseki-to decoction than in the others. Calcium sulfate from Gypsum Fibrosum raised ephedrine alkaloids dissolution in the Makyo-kanseki-to decoction.

Central Nervous System Stimulants↗
PubMed1999

In vivo metabolism of aloemannan.

The metabolism of fluoresceinyl isothiocyanate labeled aloemannan (FITC-AM) was examined by p.o. and i.v. administration in mice at a dose of 120 mg/kg. Analysis of FITC-AM in urine and feces showed that FITC-AM (MW 500 KD) was metabolized into smaller molecules that mainly accumulated in the kidneys. AM was catabolized by the human intestinal microflora to catabolites 1 and 2 with molecular weights of 30 and 10 KD, respectively. Hydrolysis of AM showed hexosamine peaks on HPAE. The findings suggest that the immunomodulation of AM may come from not only neutral polysaccharides but also contaminated hexosamine in AM.

Adjuvants, Immunologic↗
PubMed1999

Simultaneous determination of baicalin, wogonoside, baicalein, wogonin, berberine, coptisine, palmatine, jateorrhizine and glycyrrhizin in Kampo medicines by ion-pair high-performance liquid chromatography.

An ion-pair high-performance liquid chromatographic method for the simultaneous determination of four flavonoids, namely baicalin, wogonoside, baicalein and wogonin, and four berberine-type alkaloids, namely berberine, coptisine, palmatine and jateorrhizine, and glycyrrhizin in Kampo medicines is described. The analysis can be accomplished within 30 min with a Wakosil-II 5C18 HG column by linear gradient elution using a mobile phase containing aqueous phosphoric acid, sodium dodecyl sulfate and acetonitrile at a flow-rate of 1.0 ml x min(-1), a thermostatic oven at 45 degrees C, and detection at 265 nm. The method was applied to quantifying these components in three Kampo decoctions: Oren-gedoku-to, San'o-shashin-to and Hange-shashin-to. The decoctions were diluted with 65% methanol at the final stage because a large quantity of precipitate, mainly from baicalin and berberine, was formed. The within-day relative standard deviations were less than 2.02% (n=10). The recoveries of these compounds were 90.3-102%. The detection limits of these compounds were 0.02-1.96 microM per injection (5 microl).

Alkaloids↗
PubMed1998

An inhibitor of aldose reductase and sorbitol accumulation from Anthocepharus chinensis.

A flavonoid glycoside was isolated from Anthocepharus chinensis. Its structure was elucidated by spectral data and determined to be myricetin 3-O-(4"-acetyl)-alpha-fucoside. This flavonoid glycoside and its aglycone showed potent inhibition against rat and porcine lens aldose reductase. The flavonoid aglycone also inhibited sorbitol accumulation in human red blood cells.

Aldehyde Reductase↗
PubMed1998

Immunochemical distinction of Aloe vera, A. arborescens, and A. chinensis gels.

Verectin antiserum raised in white rabbits was immunoprecipitated with the Aloe vera nondialysable fraction. Analysis of the immunoprecipitation revealed that verectin accounted for about 1.25% of the total proteins in the nondialysable fraction of Aloe vera gel. The verectin antibody showed differential immunoreactivities against nondialysable fractions of A. arborescens, A. chinensis, and A. vera: 1) an immunopreciptin line was formed against the fraction of A. vera, but not against those of A. arborescens and A. chinensis gel in an Ouchterlony double immunodiffusion test and 2) an immunopositive band was detected in the A. vera and A. chinensis nondialysable fractions but not in that of A. arborescens in immunoblotting. These findings indicate that the verectin antibody can be used to distinguish Aloe materials.

Animals↗
PubMed1998

Brain potentials associated with eye fixations during visual tasks under different lighting systems.

The variations of eye fixation related potentials (EFRPs) were examined in two tasks under three lighting conditions for assessment of lighting environments. Sixteen subjects participated in two tasks; a difficult and an easy reading task under three lighting conditions: Spot light (S), General light (G) and Mixed light (M). EEG (Oz) and EOG were recorded. EEG epochs time-locked to onset of eye fixations were collected at random and averaged separately in two arrays to obtain a pair of EFRPs. Two wave forms under the S were similar, although those under the G showed the disparity, the largest disparity being in the easy task under the G. Under the S, wave forms of EFRPs were stable in the difficult task. The amplitude changed with the task load. The results suggested that EFRPs might be an index of the work load under lighting conditions.

Adult↗
PubMed1998

A comprehensive system to explore p53 mutations.

To establish an effective and reliable system for the detection of p53 mutations, we evaluated the detection efficiencies of nonisotopic polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP), fluorescence in situ hybridization (FISH), and immunohistochemistry. Ten cell lines (AsPc1, BxPc3, Miapaca2, Panc1, Colo320-011, Lovo, MCF7, LNCaP, HL-60, and Daudi), a peripheral blood sample from a patient with a p53 germline mutation (p53GML), and a normal peripheral blood sample were used for examination. Direct nucleotide sequencing identified p53 mutations in 7 of 12 samples (AsPc1, BxPc3, Miapaca2, Panc1, Colo320-011, HL-60, and p53GML). The nonisotopic PCR-SSCP detected anomalies of the PCR fragments in 5 cell lines. In the FISH analysis, 2 cell lines exhibited loss of heterozygosity of the p53 locus. Immunohistochemistry detected an accumulation of the abnormal p53 in 4 cell lines. The combination of these 3 methods produced no false-negative or false-positive results. This combination may be an excellent and beneficial system for the clinical diagnosis of the various human cancers.

Cell Line↗
PubMed1998

[Phonological priming and auditory event-related brain potentials].

Phonological priming effects on auditory event-related brain potentials were compared across different numbers of syllables shared between target words and preceding prime words or pseudowords. All items of words and pseudowords consisted of 3 syllables, and the subject's task was to make a judgment whether the item belonged to a designated category. A large negative wave (N400), commencing at about 250 ms poststimulus and lasting for about 700 ms, was observed irrespective of primes and targets. When targets were preceded by word-primes that shared the first one or two syllables, the onset of N400 at the frontal site was earlier and the initial negative-going phase was steeper than in other conditions. In contrast, the magnitude of N400 to targets was reduced, when the primes were pseudowords that shared the first two syllables. These two types of early and later phonological priming effects were interpreted to reflect facilitations during spoken word recognition at the pre-lexical (phonological) and post-lexical (semantic or contextual integration) levels, respectively.

Adult↗
PubMed1998

Topostatin, a novel inhibitor of topoisomerases I and II produced by Thermomonospora alba strain No. 1520. I. Taxonomy, fermentation, isolation and biological activities.

A novel inhibitor of topoisomerases designated as topostatin was isolated from the culture filtrate of Thermomonospora alba strain No. 1520. Topostatin inhibited the relaxation of supercoiled pBR322 DNA by calf thymus topoisomerase I, and also inhibited the relaxation of supercoiled pBR322 DNA and decatenation of kinetoplast DNA by human placenta topoisomerase II. Topostatin had neither ability to stabilize the cleavable complex nor ability to intercalate into DNA strands. The inhibitor exhibited growth inhibitory activity against the tumor cells (SNB-75 and SNB-78) of central nervous system, but did not exhibit any antimicrobial activity against Gram-positive and Gram-negative bacteria, yeasts and fungi.

Antineoplastic Agents↗
PubMed1997

Isolation and characterization of the glycoprotein fraction with a proliferation-promoting activity on human and hamster cells in vitro from Aloe vera gel.

Fractions of leaf gel from Aloe barbadensis Mill. were prepared by gel permeation using DEAE Sephadex A-25, Sepharose 6B, and Sephadex G-50 columns. These were then tested by in vitro assays for proliferation of human normal dermal and baby hamster kidney cells. The glycoprotein fraction promoted cell growth, while the neutral polysaccharide fraction did not show any growth stimulation. Moreover, the polar-colored glycoprotein fraction strongly inhibited the in vitro assays. An active glycoprotein fraction (protein 82%, carbohydrate 11%) examined on polyacrylamide gel electrophoresis (PAGE) and SDS-PAGE showed a single band. Its molecular weight was 29 kD on a Sephadex G-50 column and its isoelectric point was pH 6.8. Immunoblotting after SDS-PAGE showed that the glycoprotein was composed of two subunits (14 kD). Deglycosylation of glycoprotein (Pg21-2b fraction) by trifluoromethanesulphonic acid provided a protein band with a molecular weight of 13 kD on SDS-PAGE. The colored glycoprotein fraction was shown on SDS-PAGE to be a mixture with a molecular weight of 18 kD-15 kD. It was later hydrolyzed with 10% H2SO4 to produce phenolic substances.

Aloe↗
PubMed1997

Androgen-dependent expression of prolactin in rat prostate epithelium in vivo and in organ culture.

Peptide hormones and growth factors are involved in the regulation of prostatic cell proliferation, differentiation, and programmed cell death, which functions are primarily controlled by androgen. In carcinogenesis, prostatic cancer cells often lose androgen dependence and become largely dependent on local growth factors. The prostatic cancer cells able to respond to factors other than androgen by proliferation and inhibition of apoptosis are possibly able to survive. We demonstrate that prostatic epithelium expresses prolactin mRNA and protein in a characteristic manner. By using in situ hybridization, an overall distribution of prolactin mRNA was demonstrated in the epithelium of rat dorsal and lateral prostate, whereas a very specific localization of prolactin protein to single cells was observed by immunohistochemistry in the same tissues. In these cells, immunoelectron microscopy showed that prolactin was primarily localized to the secretory granules. These data demonstrate a selective regulation of prostatic prolactin at least at the level of transcript processing/translation and/or protein accumulation and secretion. In addition, the expression of prolactin protein in rat dorsal and lateral prostate was found to be androgen dependent in vivo in castrated and in castrated, testosterone-treated rats, as well as in vitro in organ cultures. Our results support the concept of an autocrine/paracrine loop of prolactin action in prostate where it could mediate some of androgen actions. Also, locally synthesized prolactin might belong to the factors that take over androgen regulation of prostatic cancer cells during the development of androgen-independent growth.

Androgens↗
PubMed1996

Growth of cultured human bronchiogenic epithelioid CCD-14 Br cells and dermal fibroblasts, NB1 RGB treated with ginseng tetrapeptide and its isomer.

The configurations of the component amino acids in ginseng tetrapeptide 1 isolated from Panax ginseng were determined by HPLC with an optical resolution column and the structure of 1 was established to be H-L-Val-gamma-D-Glu-D-Arg- Gly-OH. Synthesis of the ginseng tetrapeptide, 1, and of the configuration and conjugation isomers, H-L-Val-gamma-L-Glu-L-Arg-Gly-OH (2), H-L-Val-D-Glu- D-Arg-Gly-OH (3), and H-L-Val-L-Glu-L-Arg-Gly-OH (4) was carried out by a solid-phase method using the Fmoc strategy. The effects of 1-4 on the proliferation of baby hamster kidney (BHK)-21 cells, normal female bronchiogenic epithelioid (CCD-14 Br) cells, and normal human epidermal fibroblast (NB1 RGB) were examined. Only 1 showed 32 and 23% enhancement of BHK-21 and human CCD-14 Br cells growth, respectively, at a concentration of 13.6 microM and 41% enhancement of NB1 RGB cells growth at a concentration of 32 microM under the conditions employed. It was shown that both the configuration of the component amino acids and the peptide conjugation at a gamma-position of D-Glu in 1 are important for proliferation of the cells. Compound 1 exerted a prominent effect on cell stimulation and growth rate without any morphological change and showed no cytotoxicity.

Amino Acid Sequence↗