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Biomedical subjects

Y Kataoka

Publications and source records attributed to Y Kataoka.

At least 19 recordsLinked to original sources
PubMed2006

Mental fatigue-induced decrease in levels of several plasma amino acids.

To investigate the relation between plasma amino acid levels and mental fatigue, we measured the plasma concentrations of 20 amino acids in 9 healthy volunteers before and after a fatigue-inducing mental task session for 8 hr. As fatigue-inducing mental tasks, the subjects performed an advanced trail making test, a Japanese KANA pick up test, and a mirror drawing test. As a control, 8-hr relaxation session was performed in the same subjects at an interval of 4 weeks. Immediately after the fatigue session, the plasma levels of branched-chain amino acids, tyrosine, cysteine, methionine, lysine, and arginine were below those after a relaxation session. The values for other blood parameters including total protein, albumin, glucose, and total cholesterol did not show any differences between the 2 sessions. These results indicate that mental fatigue may be characterized by a decrease in the plasma level of these amino acids.

Adult↗
PubMed2006

Propofol acts at the sigma-1 receptor and inhibits pentazocine-induced c-Fos expression in the mouse posterior cingulate and retrosplenial cortices.

BACKGROUND: The sigma-1 receptor is functionally linked with psychotomimetic effects of various drugs. A sigma-1 receptor agonist enhances bradykinin-induced intracellular Ca(2+) concentration ([Ca(2+)]i) increase and induces c-Fos expression in a part of the brain. The aim of this study was to investigate the effects of several intravenous anaesthetics on the sigma-1 receptor. METHODS: First, using Wistar rat brains, (+)[(3)H]SKF-10,047, a selective sigma-1 receptor agonist was displaced by propofol, dexmedetomidine, droperidol, and thiopental. Second, Fura-2 loaded NG-108 cells were incubated with (+)pentazocine, a selective sigma-1 receptor agonist, and propofol and then its fluorescence was observed after stimulation with bradykinin. Third, male ICR mice received Intrafat or propofol intraperitoneally (i.p.), followed by pentazocine i.p. Brain slices were prepared and Fos-like immunoreactivity was detected using an immunohistochemical method. results: Propofol, droperidol, and dexmedetomidine displaced (+)[(3)H]SKF-10,047 binding in a concentration-dependent manner with Ki50s of 10.2 +/- 0.6, 0.17 +/- 0.03, 5.73 +/- 1.2 microM, respectively. Thiopental sodium was practically ineffective. Propofol produced a statistically significant reduction in the maximal binding capacity (Bmax) but did not affect the dissociation constant (K(d)). (+)Pentazocine significantly enhanced bradykinin-induced [Ca(2+)]i increases, but propofol did not affect it. Pentazocine induced marked Fos-LI positive cells in the posterior cingulate and retrosplenial cortices (PC/RS), which was significantly reduced by propofol. CONCLUSIONS: These results suggest that propofol may be a sigma-1 receptor antagonist, and that various effects of propofol on the brain may be mediated, at least partly, by the sigma-1 receptor.

Analgesics, Opioid↗
PubMed2005

Pinning of texture and vortices of the rotating B-like phase of superfluid 3He confined in a 98% aerogel.

We have investigated pinning effects on texture and vortices of the B-like phase of superfluid (3)He in a rotating aerogel up to +/-2pi rad/s by cw-NMR. We observed deformation of the NMR spectra in rotation, due to counterflow between the superflow and the normal flow. The average intensity of the counterflow was calculated from the change of NMR spectra. The rotation dependence of the counterflow intensity is similar to the magnetization curve of hard type II superconductors or the counterflow response of (4)He-II in packed powders. This counterflow behavior is in qualitative agreement with a model that vortices are pinned unless the counterflow exceeds a critical velocity v(c). The temperature independence of v(c) suggests that v(c) is associated with the expansion of primordial vortices.

Journal Article↗
PubMed2005

The change of hemodynamics and heart rate variability on bathing by the gap of water temperature.

Bathing in Japanese style may carry negative effects as water pressure on the chest and thermal stimulus on hemodynamics take place. We have explored the influence of bathing in high temperature water on the change of heart rate variability (HRV). Fourteen young healthy male adults, ageing in range from 28 to 42 years old (the average was 35.8 years old) were selected and took a hot water bath (38 and 41 degrees C) for 15 min long. Bathing in 38 degrees C water brought no significant change in heart rate (HR) and blood pressure (BP), and the HR in 41 degrees C increased in early stage. In HRV, high frequency (HF) power did not have significant change with little increase in early stages of bathing in 38 degrees C and decreased continuously in 41 degrees C. Low frequency (LF) power and very low frequency (VLF) power decreased gradually in later stages of bathing, but the degree of decrease was larger in 41 degrees C. In this study, data concerning dizziness after bathing at 41 degrees C was obtained (we named it as a "dizzy case"). HF and LF trends in this case followed the same pattern in comparison with others' average, but the decrease was larger. Additionally, there was no increase in the LF/HF at later stage of bathing. It is thought that this reflects a decreased in autonomic nerve activity. In normal subjects the VLF increased in later stages of 38 and 41 degrees C bathing, but in the dizziness-experiencing subject, the increase was very significant. It is conceivable that this reflected excessive parasympathetic reflex. Except the dizzy case HF decreased continuously in later stage of bathing in both 38 and 41 degrees C, but VLF slightly increased. Recently there was an express opinion that the VLF correlates with the prognosis; therefore the change of VLF in this study is very interesting. Based upon the results of this study we propose that the optimum period of time for bathing in water 41 degrees C in temperature is 5 min or less, and that for water 38 degrees C in temperature is 10 min or less.

Adult↗
PubMed2003

Compression and stretching of the brachial plexus in thoracic outlet syndrome: correlation between neuroradiographic findings and symptoms and signs produced by provocation manoeuvres.

In order to investigate the mechanism of nerve irritation in thoracic outlet syndrome (TOS), we studied 150 patients who presented with symptoms of neurologic TOS between 1985 and 1999. They first performed various provocative physical manoeuvres and then underwent injection of contrast medium into the supraclavicular part of the brachial plexus. Several of the provocative manoeuvres were then repeated and radiographs were again obtained. Based on the neuroradiographs, we identified three subsets of patients; those with only compression (type 1 TOS, n=27, 18%), those with combined compression and stretching (type 2 TOS, n=111, 74%), and those with only stretching (type 3 TOS, n=12, 8%). We were able to correlate the neuroradiological subsets with symptoms elicited by pre-radiographic provocative manoeuvres; in 92 patients (61%) these were elicited by traction manoeuvres. We conclude that stretching is an important factor of nerve irritation in TOS.

Adolescent↗
PubMed2002

Nasal glucagon delivery using microcrystalline cellulose in healthy volunteers.

We developed an intranasal powder form of glucagon to improve metabolic status and fatty liver in patients with pancreatectomy. Microcrystalline cellulose, which is commonly used in commercial preparations for allergic rhinitis was used as an absorption enhancer. We compared the intranasal powder form with some spray solutions of glucagon with regard to glucagon absorption, concentration of blood glucose, stability and nasal irritation. The absorption of glucagon from the spray solution including 1.5% sodium glycocholate or 1% sodium caprate was 1.3- and 2.6-fold higher than that from the powder form mixed with microcrystalline cellulose at a ratio of 1:69, respectively. The C(max) values of plasma glucose were 2.18, 3.39 and 1.56 mmol l(-1) in the spray solutions including sodium glycocholate and sodium caprate and in the powder form, respectively. However, glucagon in spray solutions was unstable, but that in the powder form was stable at 5 and 25 degrees C for at least 84 days. The spray solution caused strong irritation, but the powder form did not. These results suggested usefulness of the powder form of glucagon for treatment of pancreatectomized patients.

Administration, Intranasal↗
PubMed2002

The use of a genetically engineered herpes simplex virus (R7020) with ionizing radiation for experimental hepatoma.

The herpes simplex virus (HSV) recombinant virus R7020 is an attenuated virus designed as a candidate for immunization against both HSV-1 and HSV-2 infections. It was extensively tested in an experimental animal system and in a healthy human adult population without significant untoward effects. We report on the use of R7020 with ionizing radiation as an oncolytic agent for hepatomas. Two hepatoma cell lines were studied, Hep3B and Huh7. R7020 replicated to higher titers in Hep3B cells than in Huh7 cells. Tissue culture studies correlated with hepatoma xenograft responses to R7020. R7020 was more effective in mediating Hep3B tumor xenograft regression compared with Huh7. Ionizing radiation combined with R7020 also showed differential results in antitumor efficacy between the two cell lines in tumor xenografts. Ionizing radiation enhanced the replication of R7020 in Hep3B xenografts. Moreover, the combination of ionizing radiation and virus caused a greater regression of xenograft volume than either R7020 or radiation alone. Ionizing radiation had no effect on the replication of R7020 virus in Huh7 xenografts. These results indicate that a regimen involving infection with an appropriate herpesvirus such as R7020 in combination with ionizing radiation can be highly effective in eradicating certain tumor xenografts.

Animals↗
PubMed2001

Ménière's disease in childhood.

We report 3 rare cases of Ménière's disease in children. In Case 1 and 3, vertigo, hearing loss and tinnitus recovered soon after medical therapy. In Case 2, however, vertigo recurred and the hearing level on the right side markedly deteriorated. The equal-loudness contours on three-dimensional audiogram showed that right-sided aggravated hearing loss fluctuated for 4 years at middle-and low-frequencies despite medication. Finally intratympanic injection of gentamicin sulfate was performed. The patient has had no definitive spell of vertigo after gentamicin therapy. At our department, the incidence of Ménière's disease in pediatric patients with vertigo was 2.9%.

Adolescent↗
PubMed2001

Ovariectomy aggravates convulsions and hippocampal gamma-aminobutyric acid inhibition induced by cyclosporin A in rats.

The possible cyclosporin A application for rheumatoid arthritis that develops preferentially in middle-aged women raises concerns about adverse effects of cyclosporin A, including neurotoxicity in patients with climacterium. The present study was aimed at elucidating the effect of cyclosporin A on the convulsive activity and gamma-aminobutyric acid (GABA) neural activity of the hippocampus in ovariectomized rats, as a menopause/climacterium model. Ovariectomy markedly aggravated the effect of repeated administration of cyclosporin A (40 mg/kg, once a day for 5 or 6 days), convulsions and reduction of the basal GABA levels and aminooxyacetic acid-evoked GABA accumulation. These aggravations were blocked by estradiol replacement. The present findings demonstrated that ovariectomy increased the susceptibility to cyclosporin A-induced convulsions by accelerating an inhibitory action of cyclosporin A on GABA neural activity in the hippocampus, this being blocked by estrogen replacement. Menopause/climacterium is, therefore, included in the risk factors for cyclosporin A-induced neurotoxicity and this risk is lowered by estrogen replacement therapy.

Aminooxyacetic Acid↗
PubMed2001

Serovars of Erysipelothrix species isolated from the tonsils of healthy cattle in Japan.

Serovars of 79 Erysipelothrix isolates recovered from the tonsils of healthy slaughtered cattle over a 1-year period in Japan were determined by an agar double-diffusion precipitation system using typing sera representing all the known serovars, 1 through 23 and type N, of Erysipelothrix. A total of 43 out of the 79 Erysipelothrix isolates could be classified into nine serovars but the remaining 36 isolates were untypable. Of 42 isolates identified as Erysipelothrix rhusiopathiae, 4, 6, 2, 3, 1,12, 13 and 1 isolates belonged to serovars 1b, 2, 5, 9, 12, 13, 19 and 21, respectively. One isolate belonged to Erysipelothrix tonsillarum serovar 3.

Animals↗
PubMed2001

Activity-dependent neural tissue oxidation emits intrinsic ultraweak photons.

Living organisms have been known to spontaneously emit ultraweak photons in vivo and in vitro. Origin of the photon emission remains unclear, especially in the nervous system. The spontaneous ultraweak photon emission was detected here from cultured rat cerebellar granule neurons using a photomultiplier tube which was highly sensitive to visible light. The photon emission was facilitated by the membrane depolarization of neurons by a high concentration of K+ and was attenuated by application of tetrodotoxin or removal of extracellular Ca2+, indicating the photon emission depending on the neuronal activity and likely on the cellular metabolism. Furthermore, almost all the photon emission was arrested by 2,4-dinitrophenylhydrazine, indicating that the photon emission would be derived from oxidized molecules. Detection of the spontaneous ultraweak photon emission will realize noninvasive and real-time monitoring of the redox state of neural tissue corresponding to the neuronal activity and metabolism.

Animals↗
PubMed2001

Developmental expression of prolactin releasing peptide in the rat brain: localization of messenger ribonucleic acid and immunoreactive neurons.

Prolactin releasing peptide (PrRP) was recently identified as the stimulator of prolactin release from the anterior pituitary. PrRP mRNA is expressed in the medulla oblongata and the hypothalamus in the rat brain. The fibers containing PrRP are widely distributed in the brain, therefore, it was postulated that PrRP may act as a neurotransmitter or neuromodulator as well as an endocrine substance. To clarify the developmental changes in the expression of PrRP during brain development, we examined PrRP in rat fetuses and neonates using in situ hybridization and immunohistochemistry. The PrRP mRNA was expressed in the nucleus of the solitary tract (NTS) at embryonic day 18 (E18) and in the ventral and lateral reticular nucleus (VLRN) of the caudal medulla oblongata at E20. The PrRP mRNA in the hypothalamus was first expressed at postnatal day 13 (P13). Reverse transcription-polymerase chain reaction analysis (RT-PCR) for PrRP revealed that PCR product, a 268 bp band, was detected from either E18 in the medulla or P13 in the hypothalamus. Immunodetection with monoclonal antibody against prepro-PrRP revealed intensive staining of cells in the NTS at E18, in the VLRN at E20 or in the dorsomedial hypothalamus at P13. Immunohistochemistry using monoclonal antibody against mature PrRP at P6 showed PrRP fibers to be distributed in the paraventricular hypothalamic nucleus, periventricular hypothalamic nucleus, medial preoptic area, basolateral amygdaloid nucleus, dorsomedial hypothalamus, ventromedial hypothalamus, periventricular nucleus of the thalamus and bed nucleus of the stria terminalis as previously shown in the adult rat. PrRP fibers were also found in the optic chiasm, dorsal endopiriform nucleus, cingulum, intermediate reticular nucleus, and caudal ventrolateral reticular nucleus at P6 and P9. However, PrRP fibers were never found in the above regions in the adult animal. These findings suggest that PrRP fibers originating in the medulla oblongata have been widely distributed in the rat brain during the early postnatal day and PrRP may play various roles in the brain development.

Animals↗
PubMed2001

Activation of NFkappaB and MnSOD gene expression by free radical scavengers in human microvascular endothelial cells.

The effect of nonprotein thiol (NPT) free radical scavengers WR-1065 (SH) and WR-33278 (SS), the active thiol and disulfide metabolites of amifostine, N-acetylcysteine (NAC; both L- and D- isomers), mesna, captopril, and dithiothreitol (DTT) on NFkappaB activation in human microvascular endothelial cells (HMEC) was investigated and contrasted to TNFalpha. The use of each of these NPTs at millimolar concentrations independent of oxidative damage-inducing agents resulted in a marked activation of NFkappaB, with the maximum effect observed between 30 min and 1 h after treatment. Only the SH and SS forms of amifostine, however, were effective in activating NFkappaB when administered at micromolar levels. Using a supershift assay, SH and SS equally affected the p50-p65 heterodimer, but not homodimers or heterodimers containing p52 or c-Rel subunits of NFkappaB. Neither catalase nor pyruvate when added to the culture medium to minimize hydrogen peroxide production had an effect on NFkappaB activation by SH. Thus, while oxidative damage is known to activate NFkappaB, the intracellular redox environment may also be affected by the addition of free radical scavenging agents such as NPT, and these in turn are capable of activating the redox sensitive transcription factor NFkappaB. There does not appear to be a significant role, if any, for the production of H(2)O(2) as an intermediate step in the activation of NFkappaB by either the SH or the SS form of amifostine. Rather, the underlying mechanism of action, especially for the SS form, may be related to the close structural and functional similarities of these agents to polyamines, which have been reported to be capable of activating NFkappaB. In contrast to TNFalpha, exposure of cells to either 40 microM or 4 mM of SH for 30 min did not induce intercellular adhesion molecule-1 (ICAM-1) gene expression, but did increase manganese superoxide dismutase (MnSOD) gene expression. MnSOD expression rose by 2-fold and remained elevated from 4 to 22 h following SH exposure.

Acetylcysteine↗
PubMed2001

Protein kinase C-catalyzed phosphorylation of an inhibitory phosphoprotein of myosin phosphatase is involved in human platelet secretion.

Protein kinase C (PKC)-potentiated inhibitory phosphoprotein of myosin phosphatase (CPI) was detected in human platelets. Like smooth muscle CPI-17, in vitro phosphorylation of platelet CPI by PKC inhibited the activity of myosin phosphatase containing the PP1delta catalytic subunit and the 130-kd myosin-binding subunit (MBS). Treatment of intact platelets with thrombin or the stable thromboxane A(2) analog STA(2) resulted in increased phosphorylation of both CPI and MBS at Thr-696, whereas phorbol myristate acetate (PMA) and the Ca(++) ionophore ionomycin only induced CPI phosphorylation. PMA induced slow adenosine triphosphate (ATP) secretion of fura 2-loaded platelets with no change in cytosolic Ca(++). The PMA-induced increase in CPI phosphorylation preceded phosphorylation of 20-kd myosin light chain (MLC(20)) at Ser-19 and ATP secretion. The PKC inhibitor, GF109203X, inhibited PMA-induced phosphorylation of CPI and MLC(20) with similar IC(50) values. These findings suggest that the activation of PKC by PMA induces MLC(20) phosphorylation by inhibiting myosin phosphatase through phosphorylation of CPI. STA(2)-induced MLC(20) phosphorylation was also diminished but not abolished by GF109203X, even at high concentrations that completely inhibited STA(2)-induced CPI phosphorylation. A combination of the Rho-kinase inhibitor Y-27632 and GF109203X led to a further decrease in STA(2)-induced MLC(20) phosphorylation, mainly because of a significant inhibition of MBS phosphorylation at Thr-696. Inhibition of STA(2)-induced ATP release by Y-27632, GF109203X, or both appeared to correlate with the extent of MLC(20) phosphorylation. Thus, CPI phosphorylation by PKC may participate in inhibiting myosin phosphatase, in addition to the Rho-kinase-mediated regulation of myosin phosphatase, during agonist-induced platelet secretion. (Blood. 2001;97:3798-3805)

Adenosine Triphosphate↗
PubMed2001

Requirement of phospholipase Cdelta4 for the zona pellucida-induced acrosome reaction.

Several phospholipase C (PLC) isoforms have been found in male and female mammalian gametes, and splicing isoforms of PLCdelta4 are predominantly expressed in testis. Here we report that male mice in which the PLCdelta4 gene had been disrupted either produced few small litters or were sterile. In vitro fertilization studies showed that insemination with PLCdelta4-/- sperm resulted in significantly fewer eggs becoming activated and that the calcium transients associated with fertilization were absent or delayed. PLCdelta4-/- sperm were unable to initiate the acrosome reaction, an exocytotic event required for fertilization and induced by interaction with the egg coat, the zona pellucida. These data demonstrate that PLCdelta4 functions in the acrosome reaction that is induced by the zona pellucida during mammalian fertilization.

Acrosome↗