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Biomedical subjects

M Oguri

Publications and source records attributed to M Oguri.

At least 19 recordsLinked to original sources
PubMed1998

Effects of the gradually increasing dawn light stimulation on sleep feeling.

Effects of a new lighting stimulation system upon subjective sleep and waking feeling were psychophysiologically examined in 24 healthy students in order to develop a way of obtaining comfortable awakening. The subjects underwent three different experimental conditions: the light stimulation condition, non-light stimulation condition and the control condition. The satisfaction of sleep was higher and day sleepiness lower in the light condition compared with the other two conditions. Subjective fatigue related to mental functions at waking was also smaller in the light condition compared with the other two conditions. These results suggest that the improvement of sleep feeling and waking seems to be achieved by gradual increased dawn light stimulation.

Adult↗
PubMed1998

Expression of RANTES by bronchoalveolar lavage cells in nonsmoking patients with interstitial lung diseases.

Emphasis has recently been placed on the roles of chemotactic cytokines called chemokines to explain the accumulation of inflammatory cells in the lung that may precede or accompany pulmonary fibrosis in interstitial lung diseases. We hypothesized that RANTES, a member of the C-C chemokines, is one such chemokine. Bronchoalveolar lavage was done in 20 patients with sarcoidosis, 10 patients with interstitial pneumonia associated with collagen vascular disease (CVD-IP), 10 patients with idiopathic pulmonary fibrosis (IPF), and eight healthy volunteers (HV), all of whom were never-smokers. We semiquantitated the spontaneous RANTES mRNA expression by a competitive reverse transcription-polymerase chain reaction (RT-PCR) technique, and measured the levels of RANTES protein by enzyme-linked immunosorbent assay. In all disease groups the expression of RANTES mRNA by bronchoalveolar lavage fluid (BALF) cells and the levels of RANTES protein in BALF were significantly increased compared with those in HV. Patients with sarcoidosis and CVD-IP had a significant positive correlation between the expression of RANTES mRNA by BALF cells and BALF lymphocytosis. The amounts of RANTES mRNA expressed by peripheral blood mononuclear cells and the levels of RANTES protein in serum did not differ among all study groups. Our study demonstrates the adaptability of a semiquantitative RT-PCR method for determining cytokine mRNA expression in vivo. Our results suggest that RANTES may be one of the chemokines that are involved in the mechanism for the accumulation of inflammatory cells in the lung of some distinct interstitial lung diseases.

Bronchoalveolar Lavage↗
PubMed1997

Continuous versus bilevel positive airway pressure in a patient with idiopathic central sleep apnea.

A 57-yr-old man with idiopathic central apnea is reported. He presented at our hospital complaining of excessive daytime sleepiness. Polysomnography, including esophageal pressure monitoring, confirmed central sleep apnea with an apnea index of 27/h. He had mild non-insulin-dependent diabetes mellitus (NIDDM) but no signs of diabetic neuropathy or other background diseases. The ventilatory responses to hypoxia and hypercapnia tested while he was awake indicated increased respiratory chemosensitivity. We applied nasal continuous positive airway pressure (CPAP) and bilevel positive airway pressure (BPAP) in an attempt to compare the possible difference in therapeutic efficacy. Although nasal CPAP completely reversed central apnea, nasal BPAP adversely affected both apnea length and frequency in an applied pressure-dependent manner. Arterial blood gas analyses while he was being treated indicted alveolar hypoventilation with CPAP and hyperventilation with BPAP. Additionally, administration of a mixed gas containing 5% CO2 through a face mask had a significant effect on the disappearance of central apnea in this patient. These findings support the theory that the arterial PCO2 level is critical in generating idiopathic central apnea and that nasal CPAP therapy may be effective in eliminating central apnea by raising the PaCO2.

Blood Gas Analysis↗
PubMed1996

Seasonal variation of mood and behaviour in a healthy middle-aged population in Japan.

A population survey of seasonality in six representative cities in Japan was conducted using the Japanese version of the Seasonal Pattern Assessment Questionnaire (SPAQ). The questionnaires were given to 951 parents (male: female ratio 1:1 age range 34-59 years) of high-school students. Significant regional differences in seasonal variations of mood, length of sleep, and weight were observed; the proportion of individuals reporting high seasonality in the two northern cities was significantly higher than that in the other areas. These results provide evidence for a northern predominance in the prevalence of seasonal affective disorder in Japan.

Adult↗
PubMed1995

State-dependent respiratory and cardiac relationships with neuronal discharge in the bed nucleus of the stria terminalis.

Discharge patterns of 63 neurons in the bed nucleus of the stria terminalis (BNST) were cross-correlated with inspiratory onsets of the respiratory cycle and the R wave of the cardiac cycle in seven unrestrained, drug-free cats during waking (AW), quiet sleep (QS) and rapid eye movement (REM) sleep. BNST neurons fired slowly, with half having rates of less than 1/second; rates were higher in AW and REM states than in QS. Approximately one-quarter of cells showed a phasic discharge timing relationship with the respiratory cycle, and one-fifth with the cardiac cycle, in at least one sleep-waking state. Respiratory-cell correlations occurred more frequently during AW (18 cells) and QS (15) than REM (6), while cardiac-neuronal correlations preferentially developed during QS (13 cells) or REM sleep (11), with a smaller proportion during waking (7). Cardiac-cell discharge correlations were weaker than respiratory-cell correlations and much weaker during REM than during either AW or QS. The data suggest that sleep states modulate a respiratory-dependent neuronal discharge in this rostral site classically associated with affective functions, with the relationship being reduced during REM.

Animals↗
PubMed1994

Nephrosis augments contractile response to adrenoceptor agonists by the decrease in release of endothelium-derived relaxing factor from the endothelial cells.

The thoracic aorta was taken from nephrotic rats on the 40th day after a single i.v. injection of daunomycin (10 mg/kg). In the endothelium-intact aorta, the contractions induced by norepinephrine or B-HT 933, an alpha-2 adrenoceptor agonist, were significantly greater in nephrotic rats than in normal animals. However, such a difference was not observed in the KCl- or U46619-induced contractions. The difference in norepinephrine-induced contraction between nephrotic and normal preparations was enhanced by zaprinast, a cyclic GMP phosphodiesterase inhibitor. The contractions elicited by norepinephrine and B-HT 933 were potentiated by either removal of the endothelium or pretreatment with methylene blue, a guanylate cyclase inhibitor. The difference in the contractile response to these agonists between nephrotic and normal preparations was eliminated completely by either treatment. The cyclic GMP level in the endothelium-intact aorta in the presence of zaprinast was significantly lower in nephrotic rats than in normal animals. In the presence of zaprinast, norepinephrine, but not B-HT 933, caused an increase in the cyclic GMP level, which was abolished completely by pretreatment with prazosin, but not by yohimbine. These results suggest that the augmented contractile response to norepinephrine observed in nephrotic aorta may be due to the decrease in the stimulated release of endothelium-derived relaxing factor from the endothelial cells via the stimulation of endothelial alpha-1 adrenoceptors, whereas the augmented response to B-HT 933 may be due, at least in part, to the decrease in spontaneously released endothelium-derived relaxing factor.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1993

Early development of the pineal photoreceptors prior to the retinal differentiation in the embryonic rainbow trout, Oncorhynchus mykiss (Teleostei).

The development of the pineal and retinal photoreceptors in the embryonic rainbow trout, Oncorhynchus mykiss was investigated by means of light and electron microscopy. The pineal photoreceptors endowed with photoreceptive outer segments and signal-transmitting synapses appeared first 15 days after fertilization, and well developed by 21 days. In contrast, the retinal photoreceptors appeared as late as 27 days after fertilization (1 day before hatching). This temporal disparity in photoreceptor development has been compared with the photoperiodic formation of otolith increments, which is initiated during an early developmental stage lacking retinal photoreception. It has been suggested that the early development of pineal photoreceptors may be involved in light-dark recognition, establishment of the diel and circadian rhythms, and entrainment to the environmental photoperiod in the embryonic rainbow trout.

Animals↗
PubMed1991

Impaired endothelium-dependent relaxation in isolated thoracic aorta of rats with daunomycin-induced nephrosis.

A single i.v. injection of daunomycin (10 mg/kg) into rats produced severe proteinuria and hypercholesterolemia without atherosclerosis on the 20th and 40th days after the treatment. However, these changes were not observed on the 5th day. No change in systolic blood pressure was seen through the 40-day experimental period. Relaxation to acetylcholine, A23187 and nitroprusside was examined in aortic rings precontracted with phenylephrine (3 x 10(-6) M). Acetylcholine-induced relaxation was significantly attenuated in the nephrotic rats on the 20th and 40th days, in comparison to the control animals. In aortic rings taken from control and nephrotic rats on the 40th day, removal of the endothelium or treatment with methylene blue (10(-5) M) completely abolished the relaxation induced by acetylcholine (10(-5) M). In addition, acetylcholine (10(-5) M) induced a transient increase in the aortic cyclic GMP and this increase was completely abolished by removal of the endothelium. In the preparations of nephrotic rats on the 20th and 40th days, the cyclic GMP levels stimulated by acetylcholine (10(-5) M) were decreased to about 50% in comparison to their respective control. A23187 also evoked diminished relaxation in nephrotic rats on the 20th and 40th days. However, on the 40th day after the treatment, the effects of nitroprusside in relaxing the aorta and in elevating the cyclic GMP level in the aorta were not altered by nephrosis. In addition, the nitroprusside-induced relaxation and cyclic GMP accumulation were not affected by removal of the endothelium. These results indicate that endothelium-dependent relaxation is attenuated with the development of nephrosis.

Acetylcholine↗
PubMed1990

Contingent negative variation and reaction time of physically-trained subjects in simple and discriminative tasks.

Contingent negative variations (CNV) were recorded during the S1-S2 interval of two simple and one discriminative task at Fz, Cz and Pz of 12 physically-trained college athletes and 12 non-trained students. The reaction time to S2 was also measured. The whole mean CNV amplitude average over the 2 sec S1-S2 interval and the segmented CNV amplitudes of the 250 msec epochs were submitted to 4-way ANOVA (physical training x task x electrode position x gender), while the mean reaction time was analyzed by 3-way ANOVA. The whole mean CNV amplitude and all the segmented CNV amplitudes were greater in the physically-trained group than in the non-trained group. In all tasks the mean reaction times of the physically-trained group were significantly shorter than those of the non-trained group. The main effect of gender was not statistically significant with respect to the CNV amplitudes and the mean reaction time. The increased CNV amplitude and the shortened reaction time of the physically-trained group were discussed in relation to the reported psychophysiological correlates of CNV. The present study shows that CNV provides a technique of possible value for assessing attention and motor preparation of workers engaged in vigilance tasks.

Adult↗
PubMed1988

Changes in sleep and wakefulness following single and repeated exposures to toluene vapor in rats.

Male rats with indwelling electrodes for electroencephalographic (EEG), electromyographic (EMG) and electrooculographic (EOG) recordings were exposed via inhalation to 900 ppm and 2700 ppm toluene vapor continuously for a 8-h period or repeatedly for 3 weeks at a rate of 8 h/day and 5 days/week. Rats exposed to a clean air-stream under the same exposure schedules served as controls. Polygraphic recordings were made on 3 consecutive days after cessation of the single 8-h and repeated 3-week exposures to 900 ppm and 2700 ppm toluene vapor or clean airstream. Amounts of time spent in wakefulness (W), slow-wave sleep (SWS) and paradoxical sleep (PS) were quantified by visual inspection of the polygraphic records. Single exposure to toluene produced a prolonged PS latency and a long-lasting increase in SWS at the expense of depressed W, whereas repeated exposures prolonged both SWS and PS latencies, abolished the initial increase of SWS and increased the light-phase level of W on Days 1 and 2. The prolonged PS latency and the decreased light-phase PS on Day 2 induced by single exposure to toluene still persisted after repeated exposures. There were no statistically significant differences in attenuation of brain and blood toluene levels between single and repeated exposures to toluene vapor of 900 ppm and 2700 ppm.

Animals↗
PubMed1988

Involvement of retinal and extraretinal photoreceptors in the mediation of nocturnal locomotor activity rhythms in the catfish, Silurus asotus.

Retinal and extraretinal photoreceptor organs involved in synchronization of nocturnal locomotor activity under 12-h light:12-h dark cycle (LD12:12) were investigated in catfish, Silurus asotus. Catfishes studied were: (1) intact; (2) pinealectomized; (3) blinded; (4) blinded and pinealectomized; and (5) blinded, pinealectomized, with the brain region covered with aluminum foil. When the light intensity was reduced during the light phase of the LD cycle, the threshold for 24-h rhythmicity was determined, by observing the synchronization to the given LD cycle with periodograms. Intact catfish showed almost the same threshold intensity (in the order of 10(-3) microW/cm2) as that of either blinded or pinealectomized animals. This suggests that information is combined through both organs and is related to the 24-h rhythm of locomotor activity at lower intensities. However, the animal without the eye and pineal organ could display 24-h rhythmicity at intensities higher by approximately 3 log units than those of the animals described above. This indicates the existence of extraretinal and non-pineal photoreceptors (ENPs), and the involvement of at least three types of photoreceptor in mediating nocturnal locomotor activity rhythms at higher intensities. One of the possible ENPs was assumed to be in the brain region.

Animals↗
PubMed1985

Vertical spread of neuronal activity within the cat motor cortex investigated with epicortical stimulation and intracellular recording.

In the encéphale isolé cat preparation the surface of precruciate cortex was electrically stimulated. Intracellular responses underneath the stimulated site were recorded to assess the vertical spread of activities across the cortical layers. To the epicortical stimulation (EPICS) with intensity adjusted to evoke a pure negative wave in the direct cortical response (DCR), only some neurons in relatively superficial layers responded with excitatory postsynaptic potentials (EPSPs). Stimuli intensified to evoke both the negative and subsequent positive waves in DCR produced in all tested cells either EPSPs, inhibitory postsynaptic potentials (IPSPs), or both. Direct or axonal antidromic excitation of the cell was observed only infrequently. Cells with EPSPs distributed through all the layers with two peak populations in laminae II and V-VI. Those with IPSPs were located mainly in the upper half of lamina III with a few in more superficial as well as in deeper layers. Both EPSPs and IPSPs showed mono- or oligosynaptic latencies (0.6-10 msec) that tended to become longer in deep than in superficial layers. Some deep layer cells including fast and slow pyramidal tract cells showed slowly rising monosynaptic EPSPs of dendritic origin. Further late responses consisted of EPSPs, IPSPs, disfacilitation (DF), and disinhibition (DI). DF or DI occurred in some deep layer cells. Two modes of vertical spread of activities were postulated: one the cascade transmissions which increased response repertoire toward the depths, and the other the electrotonic spread of EPSPs along dendrites.

Animals↗
PubMed1979

Effect of thymosin on lymphoid cells from human fetal organs.

Human fetal lymphoid cells from the thymus, blood, spleen, liver, and kidney of twelve 6-to-24-wk-old fetuses were studied for their ability to respond to thymosin by the alteration of E-rosette forming cells (E-RFC) and EAC-rosette forming cells (EAC-RFC). The preincubation of spleen cells with 100 micrograms thymosin-V1 effected a statistically significant increase in E-RFC, while no changes were observed in the lymphoid cells from blood or other organs. EAC-RFC assay revealed some increases in blood, thymus, and spleen; however, they were not statistically significant. Our results suggest that the fetal spleen may play an important role in the development of primitive immunocytes into mature cells and that this development is affected by thymic hormone.

Cell Differentiation↗
PubMed1979

Studies of T lymphocyte function and inhibitory factors in minimal change nephrotic syndrome.

Plasma obtained from patients with MCNS in active stage suppressed the 3H-TdR incorporation of autologous or homologous lymphocytes stimulated with PHA-P and E rosette formation, while plasma from patients in remission did not. The depressed mitogenic response of lymphocytes from patients in the active stage significantly improved when the patient's plasma was substituted for the plasma from inactive MCNS or healthy persons and fetal calf serum. In the preliminary experiment, it was seen that the inhibitory factors were heat stable at 56 degrees C, unadsorbable to charcoal powder and retained in both the permeable and impermeable fractions of collodion bag.

Humans↗