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Biomedical subjects

O Saitoh

Publications and source records attributed to O Saitoh.

At least 37 records · Page 2Linked to original sources
PubMed1999

Differential effects of mental stress on plasma homovanillic acid in schizophrenia and normal controls.

We previously reported that mental stress by Kraepelin's arithmetic test decreases plasma homovanillic acid (pHVA) levels in psychiatrically normal healthy human subjects. The present study was undertaken to determine whether this pattern of changes in pHVA concentrations resulting from mental stress is altered in patients with schizophrenia. Fourteen male patients with schizophrenia including those under ongoing neuroleptic treatment and 14 normal male volunteers participated in the study. Following overnight fast and restricted physical activity, the subjects performed Kraepelin's arithmetic test for 30 minutes. Plasma samples were collected immediately before and after the test for measurement of pHVA levels. A significant diagnosis by Kraepelin's test effect was observed due to a decrease in pHVA levels by the Kraepelin test in control subjects but not in patients with schizophrenia. Changes in pHVA levels during the Kraepelin test positively correlated with pre-test pHVA levels in control subjects, while this correlation was not observed in patients with schizophrenia. These results may be further support for the presence of a dopamine-dependent restitutive system in the brain. The absence of response of pHVA levels to mental stress in patients with schizophrenia may indicate that the dopamine restitutive system in these patients is disrupted or already down-regulated, as previously predicted.

Adolescent↗
PubMed1999

Treatment of obstructive sleep apnea syndrome with a Kampo-formula, San'o-shashin-to: a case report.

The following describes a 76-year-old male with obstructive sleep apnea syndrome successfully treated with a Kampo-formula, San'o-shashin-to (Formula medicamentorum tres ad dispellendi cordis). Polysomnography, performed before and after administration of San'o-shashin-to, revealed that the apnea index decreased from 11.1 events/hour to 4.1 events/hour, and that the apnea plus hypopnea index decreased from 18.4 events/hour to 10.7 events/hour. The patient was normo-weight (body mass index: 20.4 kg/m2), and events of sleep apnea and hypopnea were mostly noted during a non-rapid eye movement sleep. It is possible that San'o-shashin-to has some alleviating effects on the upper airway resistance during sleep.

Aged↗
PubMed1999

Effects of nasal continuous positive airway pressure on pulmonary haemodynamics and tissue oxygenation in patients with obstructive sleep apnoea.

We investigated the acute effects of nasal continuous positive airway pressure (CPAP) on pulmonary haemodynamics and tissue oxygenation in eight men with obstructive sleep apnoea (OSA) by means of right heart catheterization. They were tested at four dosage levels of nasal CPAP: 0, 5, 10, and 15 cmH2O. Nasal CPAP significantly reduced the cardiac index at the 10 and 15 cmH2O doses. The mean pulmonary artery pressure was significantly elevated with 10 and 15 cmH2O, and pulmonary capillary wedge pressure was significantly increased with 15 cmH2O of nasal CPAP. Pulmonary vascular resistance was significantly increased with 10 cmH2O of nasal CPAP. The 5 cmH2O dose of nasal CPAP did not affect significantly these parameters. Mixed venous oxygen tension was unchanged at any pressure. We conclude that tissue oxygenation was maintained in the OSA patients during administration of nasal CPAP, even though a high CPAP clearly affected pulmonary haemodynamics.

Adult↗
PubMed1999

Antineutrophil cytoplasmic antibodies in Japanese patients with inflammatory bowel disease: prevalence and recognition of putative antigens.

OBJECTIVE: Our aim was to investigate the prevalence of antineutrophil cytoplasmic antibodies (ANCA) in Japanese patients with ulcerative colitis (UC) and Crohn's disease (CD), and the putative antigens recognized by perinuclear staining pattern ANCA (p-ANCA)-positive sera. METHODS: Sera from UC (n = 52) and CD (n = 43) patients, and from healthy controls (n = 74) were studied. The indirect immunofluorescence (IIF) method was used for the detection of ANCA and its binding pattern. p-ANCA-positive sera were studied further for putative antigens. ELISAs using lactoferrin (Lf), myeloperoxidase (MPO), and cathepsin G (Cat G) as antigens were performed. RESULTS: ANCA was positive in 40 of the 52 (76.9%) UC (p-ANCA in 33) and in 32 of the 43 (74.4%) CD (p-ANCA in 31) patients. UC and CD patients showed significantly higher titers of p-ANCA than controls; however, no significant difference was observed between UC and CD. In UC, 23, 17, and nine of the 33 patients with p-ANCA-positive sera showed reactivity with Lf, MPO, and Cat-G, respectively. In CD, 21, 20, and 11 of the 31 patients with p-ANCA-positive sera showed reactivity with Lf, MPO, and Cat-G, respectively. Fourteen of the UC and six of the CD patients showed reactivity with two different antigens, and seven of the UC and 11 of the CD patients showed reactivity with all three antigens. The presence of anti-Lf and anti-MPO antibodies was further confirmed by Western blotting. CONCLUSIONS: ANCA is useful in distinguishing patients with IBD from normal subjects but is not sufficient for the differential diagnosis of CD and UC. p-ANCA reactivity might be derived from the recognition of heterogeneous neutrophil-associated antigens.

Adult↗
PubMed1999

Fecal eosinophil granule-derived proteins reflect disease activity in inflammatory bowel disease.

OBJECTIVES: The aims of this study were: 1) to examine whether the fecal levels of eosinophil granule-derived proteins reflect disease activity in inflammatory bowel disease (IBD); and 2) to examine the extracellular release of these proteins from eosinophils and their stability in feces by an in vitro study. METHODS: We investigated 42 patients with ulcerative colitis (UC), 37 patients with Crohn's disease (CD), and 29 control subjects. The stool samples were collected at 4 degrees C over 48 h and were homogenized. The fecal levels of eosinophil cationic protein (ECP) and eosinophil protein X (EPX) were measured by radioimmunoassay. Fecal Hb (Hb), alpha1-antitrypsin (AT), and lactoferrin (Lf) were also measured by ELISA. RESULTS: Fecal ECP and EPX concentrations were significantly increased in both active UC and active CD compared to inactive UC and inactive CD, respectively. Fecal EPX concentration correlated with the fecal Hb, AT, and Lf concentrations more closely than fecal ECP concentration. Even in the inactive stage, CD patients who relapsed within the following 3 months showed higher fecal ECP and EPX concentrations compared to the patients who did not. EPX was released extracellularly more efficiently than ECP (18.6% vs 6.3%, after incubation for 15 min at 25 degrees C). EPX was more stable in the feces than ECP. CONCLUSIONS: The measurement of eosinophil granule-derived proteins in feces is useful for evaluating disease activity and predicting relapse in patients with IBD. EPX may be more suitable than ECP as a fecal eosinophil marker.

Adult↗
PubMed1998

Effects of D2 dopamine receptor agonist and antagonist on brain activity in the rat assessed by functional magnetic resonance imaging.

The effects of D2 dopamine receptor agonist, bromocriptine (BROMO), and antagonist, haloperidol (HPD), on brain activity were investigated in rats by functional magnetic resonance imaging. T2*-weighted signal intensity was increased in the hypothalamus at 120 min after acute administration of BROMO, and in the ventral posterior and dorsomedial nuclei of the thalamus from 30 to 120 min. In contrast, the signal intensity was decreased in the caudate-putamen at 30 min after acute administration of HPD, in the hypothalamus from 30 to 60 min, and in the perirhinal cortex at 30 min. After chronic (2 weeks) HPD treatment, acute administration of HPD decreased signal intensity in the caudate-putamen at 60 min, in the hypothalamus at 30 min, the perirhinal cortex from 2 to 120 min, the dorsomedial and ventral posterior nuclei of the thalamus from 2 to 120 min, and the medial nucleus of the amygdala from 60 to 120 min. These results suggest that (1) the D2 receptor agonist increased the activity of the thalamic nuclei and the hypothalamus, while the D2 receptor antagonist suppressed brain activity in the regions where D2 receptors were present, (2) the suppression of brain activity in the thalamic nuclei and the perirhinal cortex by acute HPD administration was enhanced by chronic HPD treatment, and (3) the effects of antipsychotic drugs on the thalamus, amygdala, and perirhinal cortex may be related to their therapeutic efficacy, since clinical improvement in schizophrenic patients appears several days after the start of HPD treatment.

Amygdala↗
PubMed1998

Effect of mental stress on plasma homovanillic acid in healthy human subjects.

Plasma levels of homovanillic acid (pHVA) have been suggested to provide a measure of dopaminergic activity in the central nervous system. The present study investigated the effect of mental stress by the Kraepelin test, a test of continuous arithmetic addition of single-digit figures for 30 min, on pHVA levels in 13 male psychiatrically normal healthy volunteers. Following an overnight fast and restricted physical activity, plasma samples were collected immediately before and after the administration of the Kraepelin test. Plasma HVA levels following the administration of the Kraepelin test were significantly lower than the pretest pHVA levels. The percent change in pHVA levels by the Kraepelin test positively correlated with pretest pHVA levels. The observed reduction in pHVA levels by mental stress in normal subjects may reflect some aspects of a dopamine-dependent restitutive system in the brain.

Adult↗
PubMed1998

A case of subwakefulness syndrome.

We report a patient, a 30-year-old male Japanese-Brazilian migrant construction worker, suffering from excessive daytime sleepiness for at least 6 months. Electroencephalogram recordings during his waking states showed that 10-Hz and 60-microV alpha activity was present prominently in the occipital regions. From the multiple sleep latency test, it was found that stages 1-2 NREM sleep episodes appeared repetitively without any REM episodes, and that the mean sleep latency was 10.2 min. These findings support the diagnosis that this patient suffers from subwakefulness syndrome.

Adult↗
PubMed1998

Magnetic resonance imaging study of the brain in autism.

Autism is a neuropsychiatric disorder of social, cognitive, and language development. Cerebellar abnormality in autism has been shown consistently from autopsy and magnetic resonance image (MRI) studies. A new MRI study with careful methodologic designs identified two subgroups of autistic patients: hypoplasia and hyperplasia of cerebellar vermian lobules VI-VII. The existence of these two subtypes was also supported via the meta-analysis of data from separate research groups. In addition to the cerebellar abnormality, recent MRI studies in autism demonstrated abnormalities in the parietal lobe and the posterior subregions of the corpus callosum where parietal cortical fibers are concentrated. Furthermore, neurobehavioral correlates of cerebellar and parietal abnormalities have also been investigated. In contrast, there is a lack of significant difference in the cross-sectional size of the posterior hippocampal formation between autistic and normal subjects, which is discrepant with predictions based on some autopsy studies.

Autistic Disorder↗
PubMed1998

Bile acids inhibit tumour necrosis factor alpha-induced interleukin-8 production in human colon epithelial cells.

To clarify the regulatory mechanism of the production of various inflammatory mediators by intestinal epithelial cells, the effect of bile acids (tauroursodeoxycholate, TUDC; taurochenodeoxycholate, TCDC; and taurocholate, TC) on the cytokine-induced production of interleukin (IL)-8 in a human colon epithelial cell line (HT-29) was examined. HT-29 cells were incubated for 24 h in a culture medium containing tumour necrosis factor alpha (TNF alpha; 1 ng/mL) and/or interleukin (IL)-1beta (1 ng/mL) in the presence or absence of bile acids. The IL-8 concentration in the medium was measured by an enzyme-linked immunosorbent assay. The binding assay of TNF alpha was performed using [125I]-TNF alpha (100 pmol/L). Interleukin-8 production during incubation with TNF alpha was markedly reduced in the presence of 0.5 and 1 mmol/LTUDC, 0.5 and 1 mmol/LTCDC and 0.5 and 1 mmol/LTC, by 56, 85, 86, 91, 37 and 70%, respectively. The IL-8 production during incubation with IL-1beta was not significantly reduced in the presence of these bile acids. The specific binding of TNF alpha to cells was inhibited 33, 47, and 14% by 1 mmol/LTUDC, TCDC and TC, respectively. These findings suggest that bile acids inhibit TNF alpha-induced IL-8 production by the colonic cells. The suppression may be partly due to inhibition of TNF alpha binding to the cells by bile acids.

Bile Acids and Salts↗
PubMed1997

RGS8 accelerates G-protein-mediated modulation of K+ currents.

Transmembrane signal transduction via heterotrimeric G proteins is reported to be inhibited by RGS (regulators of G-protein signalling) proteins. These RGS proteins work by increasing the GTPase activity of G protein alpha-subunits (G alpha), thereby driving G proteins into their inactive GDP-bound form. However, it is not known how RGS proteins regulate the kinetics of physiological responses that depend on G proteins. Here we report the isolation of a full-length complementary DNA encoding a neural-tissue-specific RGS protein, RGS8, and the determination of its function. We show that RGS8 binds preferentially to the alpha-subunits G(alpha)o and G(alpha)i3 and that it functions as a GTPase-activating protein (GAP). When co-expressed in Xenopus oocytes with a G-protein-coupled receptor and a G-protein-coupled inwardly rectifying K+ channel (GIRK1/2), RGS8 accelerated not only the turning off but also the turning on of the GIRK1/2 current upon receptor stimulation, without affecting the dose-response relationship. We conclude that RGS8 accelerates the modulation of G-protein-coupled channels and is not just a simple negative regulator. This property of RGS8 may be crucial for the rapid regulation of neuronal excitability upon stimulation of G-protein-coupled receptors.

Amino Acid Sequence↗
PubMed1997

Molecular identification of a G protein-coupled receptor family which is expressed in planarians.

We identified four guanine nucleotide binding protein (G protein)-coupled receptors from planarians by polymerase chain reaction (PCR) with degenerate primers. They all showed a significant homology to human 5HT1A serotonin receptor and therefore were designated as serotonin receptor-like planarian receptor 1 similar to 4 (5HTLpla1 similar to 4). cDNA clones of 5HTLpla4 and 5HTLpla1 were isolated from the planarian cDNA library and their complete nucleotide sequences were determined. The deduced amino acid sequences of these planarian receptors, which are highly homologous to one another, show significant similarity to that of Drosophila 5HTdrol serotonin receptor. Northern blot analysis revealed that expression of 5HTLpla4 mRNA increased during planarian regeneration, suggesting that 5HTLpla4 might be involved in the regeneration mechanism.

Amino Acid Sequence↗
PubMed1997

Behavioral and P3 amplitude enhancement in schizophrenia following feedback training.

In order to clarify the remediability of behavioral and electrophysiological abnormalities in schizophrenia, hit rate, reaction time, and P3 amplitude from auditory event-related potentials were evaluated before and after feedback training of a task in 14 schizophrenics and 12 age-matched normal controls. Although mean changes in the three indices due to the training were nonsignificant in both schizophrenic and normal control groups as a whole, the changes in hit rate and reaction time correlated significantly with the P3 amplitude change in the schizophrenic (r = 0.60 and -0.58, respectively) but not in the normal control group. The P3 amplitude change also correlated with the P3 amplitude before the training only in the schizophrenic group (r = -0.68), suggesting that the training was more effective for the schizophrenic patients with marked P3 amplitude reduction. The observed P3 amplitude increase due to training may represent an electrophysiological correlate of a remediable aspect of behavioral deficits in schizophrenics, which may underlie the effectiveness of nonpharmacological treatments.

Adult↗
PubMed1997

Saccadic eye movements and regional cerebral blood flow in schizophrenic patients.

This study examined saccadic eye movements, using simple stationary targets, in schizophrenic patients. The targets were eight black points or eight arabic-numbered points placed in randomized order on the circumference of a circle. Self-paced eye movements during clockwise tracking of these points, by 23 patients and 23 controls, were recorded using an infrared eye-mark recorder. Then the relationship between the saccades and clinical symptoms was investigated. Finally, the relationship between the performance of the saccades and resting regional cerebral blood flow (rCBF) was examined using single photon emission computed tomography with 99mTc-hexamethyl propyleneamine oxime (HMPAO). The results indicate that patients track with significantly fewer correct scores and more deviant scores than controls, in agreement with our previous study. There were two groups of patients: an ordinary group who obtained a full-target-hitting score at a 200-ms setting and a fast group who obtained the full score at 100 ms but not at 200 ms. Some patients displayed significantly more hypermetria than controls. Significant correlations were found between hallucination and delusion symptoms and correct score. With respect to relative rCBF, fast-group patients showed significantly decreased rCBF in the left limbic and inferior parietal areas as compared with ordinary group patients. These findings suggest that some schizophrenic patients view the stationary targets too fast and this may be related to dysfunction in the limbic-parietal association area in the left hemisphere.

Adolescent↗
PubMed1997

Cyclosporine A inhibits interleukin-8 production in a human colon epithelial cell line (HT-29).

Intestinal epithelial cells produce various inflammatory mediators. However, the way in which immunosuppressive agents influence the production of these mediators by intestinal epithelial cells is not understood. The effects of cyclosporine A (CsA), tacrolimus (FK506), and dexamethasone (DEX) on cytokine-induced production of interleukin (IL)-8 in a human colonic cancer cell line (HT-29) were examined. HT-29 cells were stimulated with either IL-1 beta or tumor necrosis factor alpha (TNF alpha) together with CsA, FK506, or DEX. The presence of IL-8 protein was detected by enzyme-linked immunosorbent assay, and the expression of IL-8 messenger RNA (mRNA) by reversetranscription polymerase chain reaction. CsA (1, 5, and 10ng/ml) significantly reduced IL-1 beta-induced IL-8 production (by 32%, 41%, and 48%, respectively), and reduced TNF alpha-induced IL-8 production (by 21%, 42%, and 50%, respectively). FK506 or DEX had no effect on IL-1 beta- or TNF alpha-induced IL-8 production. The expression of IL-8 mRNA was also inhibited by CsA. These findings suggest that CsA may influence the production of inflammatory mediators in colonic cells in a different manner from FK506 and DEX.

Cell Count↗
PubMed1996

Identification of planarian serotonin receptor by ligand binding and PCR studies.

Binding sites for [3H]lysergic acid diethylamide (LSD), a serotonin receptor agonist, were identified in planarian membranes by ligand binding studies. The Kd and Bmax values were approximately 4 microM and 0.2 pmol mg-1 protein, respectively. The serotonin (5-HT) receptor antagonists methiothepin and dihydroergocriptine were also efficient displacers of [3H]LSD binding. When planarians were decapitated in the presence of these antagonists, head regeneration was significantly retarded. These results suggest that planarians possess LSD binding sites which are involved in the process of regeneration. Furthermore, we found a putative (5-HT) receptor expressed in planarians by the degenerate primer polymerase chain reaction.

8-Hydroxy-2-(di-n-propylamino)tetralin↗