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Biomedical subjects

S Nohara

Publications and source records attributed to S Nohara.

At least 19 recordsLinked to original sources
PubMed2003

Gray matter features of schizotypal disorder patients exhibiting the schizophrenia-related code types of the Minnesota Multiphasic Personality Inventory.

OBJECTIVE: Previous studies have suggested that several code types of the Minnesota Multiphasic Personality Inventory (MMPI) are useful markers for identifying schizophrenia. We hypothesized that schizotypal disorder (STD) patients with such schizophrenia-related code types have the morphological brain abnormalities associated with schizophrenia. METHOD: Voxel-based morphometric analysis with statistical parametric mapping (SPM) 99 software was used to investigate the differences in brain morphology between 14 STD patients with the schizophrenia-related code types of the MMPI and 28 normal individuals. RESULTS: The STD patients showed significantly decreased gray matter volume in the insular regions bilaterally and in the left entorhinal cortex, compared with the controls. CONCLUSION: Our findings suggest that STD patients with the schizophrenia-related code types have volume reductions in these regions as an endophenotype that overlaps with schizophrenia.

Adolescent↗
PubMed2002

Statistical parametric mapping in brain single photon computed emission tomography after carbon monoxide intoxication.

The purpose of this retrospective study was to assess regional cerebral blood flow in patients after carbon monoxide intoxication by using brain single photon emission computed tomography and statistical parametric mapping. Eight patients with delayed neuropsychiatric sequelae and ten patients with no neuropsychiatric symptoms after carbon monoxide intoxication were studied with brain single photon emission tomography imaging with 99mTc-hexamethyl-propyleneamine oxime. Forty-four control subjects were also studied. We used the adjusted regional cerebral blood flow images in relative flow distribution (normalization of global cerebral blood flow for each subject to 50 ml x 100 g(-1) x min(-1) with proportional scaling) to compare these groups with statistical parametric mapping. Using this technique, significantly decreased regional cerebral blood flow was noted extensively in the bilateral frontal lobes as well as the bilateral insula and a part of the right temporal lobe in the patients with delayed neuropsychiatric sequelae as compared with normal volunteers (P< 0.005). In the patients with no neuropsychiatric symptoms, significantly decreased regional blood flow in the bilateral frontal lobes particularly on the left side was detected. There was a significantly decreased regional cerebral blood flow in the right frontal lobe and insula in the patients with delayed neuropsychiatric sequelae as compared to those with no neuropsychiatric sequelae. It is concluded that statistical parametric mapping is a useful technique for highlighting differences in regional cerebral blood flow in patients following carbon monoxide intoxication as compared with normal volunteers. The selectively reduced blood flow noted in this investigation supports the contention that the decrease following carbon monoxide intoxication may be prolonged and further worsen in the frontal lobe. In addition, the present study may help to clarify the characteristics of the pathophysiological alteration underlying delayed neuropsychiatric sequelae.

Adult↗
PubMed2001

The effect of tandospirone, a serotonin(1A) agonist, on memory function in schizophrenia.

BACKGROUND: The purpose of this study was to test the hypothesis that the addition of tandospirone, a 5-HT(1A) partial agonist, to ongoing treatment with typical antipsychotic drugs, would improve memory function in patients with schizophrenia. METHODS: Eleven outpatients (male/female = 7/4) with schizophrenia who had been on stable doses of haloperidol and biperiden were given tandospirone, 30 mg/day, for 4 weeks. The Wechsler Memory Scale-Revised (WMS-R) was administered at baseline and 4 weeks after the addition of tandospirone. The Brief Psychiatric Rating Scale (BPRS; Total, Positive, and Negative subscale scores) and the Simpson-Angus Scale for Extrapyramidal Symptoms (SAS) were also completed on the two occasions. To exclude the possibility of a practice effect on the WMS-R test, 11 age-matched patients with schizophrenia (M/F = 7/4) were tested at baseline and after a 4-week interval. RESULTS: Repeated measures analysis of variance revealed a significant time by group (patients with or without tandospirone) effect for the Verbal-, but not the Visual Memory composite scores of the WMS-R test; no significant change was observed in patients without tandospirone, whereas improvement in the Verbal Memory score was noted in patients receiving tandospirone. Moreover, there was improvement in the Inclusion score, an index of memory organization as measured by the Logical Memory subtest of WMS-R, only in patients with tandospirone. Scores on the BPRS and SAS were improved during treatment with tandospirone, but the effects did not reach statistical significance. CONCLUSIONS: The results suggest that adjunctive treatment with 5-HT(1A) agonists may improve some types of memory function in schizophrenia.

Adult↗
PubMed2001

Magnetic resonance imaging study of the cavum septi pellucidi in patients with schizophrenia.

OBJECTIVE: High-resolution magnetic resonance imaging was used to evaluate the prevalence of the cavum septi pellucidi (CSP) in 79 normal subjects and 86 patients with schizophrenia. METHOD: The CSP was assessed by counting the number of consecutive coronal 1-mm slices containing the CSP. A CSP equal to or greater than 6 mm in length was defined as large. RESULTS: The CSP was found in 74.4% of the patients and 74.7% of the normal subjects, a nonsignificant difference. No difference between groups was found in the prevalence of a large CSP. CONCLUSIONS: The findings support the idea that a small CSP is a normal anatomical variant. More cases of a large CSP are needed to elucidate the implications of this abnormality in schizophrenia.

Adult↗
PubMed2001

Enhancement of cognitive performance in schizophrenia by addition of tandospirone to neuroleptic treatment.

OBJECTIVE: The goal of this study was to evaluate the effects of the addition of tandospirone, a serotonin-1A (5-HT(1A)) agonist, to ongoing treatment with typical antipsychotic drugs, on two cognitive domains that are relevant to functional outcome in patients with schizophrenia. METHOD: Twenty-six patients with schizophrenia who were receiving stable doses of typical antipsychotics were randomly assigned to adjunctive treatment with 30 mg/day of tandospirone or placebo for 6 weeks. Executive function and verbal memory as well as psychopathology were assessed at baseline and after 6 weeks. RESULTS: Both cognitive measures improved significantly in the patients who received tandospirone; subjects who did not receive tandospirone showed no change. There was no significant change in psychopathology ratings in either group. CONCLUSIONS: The results suggest the usefulness of 5-HT(1A) agonists for enhancing some types of cognitive performance and possibly social and work function in patients with schizophrenia.

Antipsychotic Agents↗
PubMed2000

Neural correlates of memory organization deficits in schizophrenia. A single photon emission computed tomography study with 99mTc-ethyl-cysteinate dimer during a verbal learning task.

Regional cerebral blood flow (rCBF) during a verbal learning task was measured using 99mTc-ethyl-cysteinate dimer and single photon emission computed tomography in 10 patients with schizophrenia and nine normal controls. Verbal repetition was used as a control task. The schizophrenic patients showed failure to spontaneously utilize implicit category information to learn the word lists. In the normal controls, rCBF in the left inferior frontal and left anterior cingulate regions was significantly increased during the verbal learning task, compared with the verbal repetition task. In contrast, there was no significant frontal lobe activation by the verbal learning in the schizophrenic patients. The patients had lower rCBF during the verbal learning task than the controls in the bilateral inferior frontal, left anterior cingulate, right superior frontal, and bilateral middle frontal regions. Activation in the left inferior frontal region was significantly positively correlated with categorical clustering in the task in the controls, but no such correlation was found in the patients. These results indicate that memory organization deficits in schizophrenia may be related to dysfunction in the prefrontal areas, especially in the left inferior frontal region.

Adult↗
PubMed2000

Origin and evolution of the colonial volvocales (Chlorophyceae) as inferred from multiple, chloroplast gene sequences.

A combined data set of DNA sequences (6021 bp) from five protein-coding genes of the chloroplast genome (rbcL, atpB, psaA, psaB, and psbC genes) were analyzed for 42 strains representing 30 species of the colonial Volvocales (Volvox and its relatives) and 5 related species of green algae to deduce robust phylogenetic relationships within the colonial green flagellates. The 4-celled family Tetrabaenaceae was robustly resolved as the most basal group within the colonial Volvocales. The sequence data also suggested that all five volvocacean genera with 32 or more cells in a vegetative colony (all four of the anisogamous/oogamous genera, Eudorina, Platydorina, Pleodorina, and Volvox, plus the isogamous genus Yamagishiella) constituted a large monophyletic group, in which 2 Pleodorina species were positioned distally to 3 species of Volvox. Therefore, most of the evolution of the colonial Volvocales appears to constitute a gradual progression in colonial complexity and in types of sexual reproduction, as in the traditional volvocine lineage hypothesis, although reverse evolution must be considered for the origin of certain species of Pleodorina. Data presented here also provide robust support for a monophyletic family Goniaceae consisting of two genera: Gonium and Astrephomene.

Algal Proteins↗
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↗
PubMed1996

Residual pesticides and their toxicity to freshwater shrimp in the littoral and pelagic zones of Lake Kasumigaura, Japan.

Pesticide residues in water and their toxicity to the freshwater shrimp (Paratya compressa improvisa) were studied in a river mouth in Takahamairi Bay, Lake Kasumigaura, from April to July in 1987. Concentrations of fenthion, diazinon and fenobucarb in water of the littoral zone were lower than that in the pelagic zone. The maximum concentration of fenthion, diazinon, iprobenfos and simetryn in water were 1.9, 0.8, 6.5, and 1.1 micrograms 1(-1), respectively. The 4-day mortality of the freshwater shrimp increased in lake water at Takahamairi Bay, reaching 50% at maximum in May. The mortality was probably due to residual insectside fenthion.

Animals↗
PubMed1995

Subunit association of gamma-glutamyltranspeptidase of Escherichia coli K-12.

gamma-Glutamyltranspeptidase [EC 2.3.2.2] of Escherichia coli K-12 consists of one large subunit and one small subunit, which can be separated from each other by high-performance liquid chromatography. Using ion spray mass spectrometry, the masses of the large and the small subunit were determined to be 39,207 and 20,015, respectively. The large subunit exhibited no gamma-glutamyltranspeptidase activity and the small subunit had little enzymatic activity, but a mixture of the two subunits showed partial recovery of the enzymatic activity. The results of native-polyacrylamide gel electrophoresis suggested that they could partially recombine, and that the recombined dimer exhibited enzymatic activity. The gene of gamma-glutamyltranspeptidase encoded a signal peptide, and the large and small subunits in a single open reading frame in that order. Two kinds of plasmid were constructed encoding the signal peptide and either the large or the small subunit. A gamma-glutamyltranspeptidase-less mutant of E. coli K-12 was transformed with each plasmid or with both of them. The strain harboring the plasmid encoding each subunit produced a small amount of the corresponding subunit protein in the periplasmic space but exhibited no enzymatic activity. The strain transformed with both plasmids together exhibited the enzymatic activity, but its specific activity was approximately 3% of that of a strain harboring a plasmid encoding the intact structural gene. These results indicate that a portion of the separated large and small subunits can be reconstituted in vitro and exhibit the enzymatic activity, and that the expressed large and small subunits independently are able to associate in vivo and be folded into an active structure, though the specific activity of the associated subunits was much lower than that of native enzyme. This suggests that the synthesis of gamma-glutamyltranspeptidase in a single precursor polypeptide and subsequent processing are more effective to construct the intact structure of gamma-glutamyltranspeptidase than the association of the separated large and small subunits.

Amino Acid Sequence↗
PubMed1994

[Thyroid scintigraphy in patients with thyroid tumors using 99mTc-hexakis 2-methoxy isobutyl isonitrile].

Early and delayed thyroid scintigraphy with 99mTc-hexakis 2-methoxy isobutyl isonitrile (99mTc-MIBI) was performed in 18 patients with thyroid tumor, including 8 with papillary carcinoma, 1 each with follicular carcinoma, anaplastic carcinoma, and malignant lymphoma, and 7 with thyroid adenoma. Scintigrams obtained were compared with those taken with other radionuclides. In all 11 patients with malignant tumors, increased 99mTc-MIBI uptake was noted in the tumors on early images, although anaplastic carcinoma and malignant lymphoma had mild uptake. On delayed images, 99mTc-MIBI washout was noted in 45.4% (5/11). In one patient with extensive cervical lymph node metastasis, 99mTc-MIBI concentration was evident in the metastatic foci. In the 4 where, the thyroid adenoma consisted mainly of cystic degeneration, a focal defect was noted, but two of the three patients whose thyroid adenoma consisted mainly of a solid component had an intense tracer uptake in the tumors on early and delayed images. In conclusion, there were increased 99mTc-MIBI accumulations in all of the 14 solid thyroid tumors. The quality of 99mTc-MIBI scintigraphic images of thyroid tumors was equal or slightly superior to that taken with 201Tl scintigraphy. 99mTc-MIBI thyroid scintigraphy may be useful in detecting a solid thyroid tumor and its metastasis, although it cannot be used to differentiate between benign and malignant tumors.

Adenocarcinoma, Follicular↗
PubMed1993

Crystallization and preliminary X-ray analysis of gamma-glutamyltranspeptidase from Escherichia coli K-12.

gamma-Glutamyltranspeptidase (EC 2.3.2.2) from Escherichia coli K-12 has been purified and crystallized by means of vapor diffusion in hanging drops. Two kinds of crystals on cell dimensions were found for X-ray diffraction analysis, one from ammonium sulfate and the other from polyethylene glycol 6000 as precipitants. The crystals of the orthorhombic form grown in the presence of 15% polyethylene glycol and 20 mM sodium acetate buffer were chosen for further analysis. The crystals belonged to space group P2(1)2(1)2(1), with cell dimensions of a = 128.1, b = 129.9 and c = 79.2 A, and two molecules constitute an asymmetric unit. These crystals diffracted to 2.0 A resolution and were suitable for X-ray crystallographic studies.

Bacterial Proteins↗
PubMed1992

Escherichia coli gamma-glutamyltranspeptidase mutants deficient in processing to subunits.

Arginyl residues 513 and 571 of Escherichia coli K-12 gamma-glutamyl-transpeptidase (EC 2.3.2.2) were substituted with alanyl and glycyl residues, respectively, by oligonucleotide-directed in vitro mutagenesis. Both mutants were devoid of the enzymatic activity. On Western blot analysis, we found that both mutants accumulated a gamma-glutamyltranspeptidase precursor which was not processed into large and small subunits in the periplasmic space of Escherichia coli.

Alanine↗
PubMed1992

Activation of cerebral dopaminergic systems by noise and whole-body vibration.

To clarify the involvement of the central nervous system in responses of organisms to noise and whole-body vibration, the activity of dopamine (DA) neuron systems was estimated by examining DA turnover rates in various discrete regions of the brains of rats exposed to noise (broad band, 102 dB) or whole-body vibration (20 Hz, 4G) for 90 min. Plasma corticosterone level (COR) was determined simultaneously as an index of stress-induced autonomic-nervous and endocrine functions. Noise and whole-body vibration increased both COR and DA turnover rates (shown by an increase of homovanillic acid (HVA) and/or HVA/DA ratio) in the frontal cortex (FC) and the nucleus accumbens (NAc). Only noise increased the DA turnover rate in the amygdala (AMY). Furthermore, strong positive correlations of the HVA/DA ratios in the FC and the NAc with COR were observed in rats exposed to noise or vibration. These results suggest that the responses of organisms to noise and whole-body vibration may be critically mediated by cerebral DA systems, in particular by the mesocortical DA system, indicating that change of DA in the AMY can be considered a specific response to noise.

Animals↗
PubMed1992

Experimental studies on the pathogenesis of the gastric mucosal lesions induced by whole-body vibration.

In order to determine the pathogenesis of gastric mucosal lesions induced by whole-body vibration (WBV), the effects of WBV (3.0 G, 10 Hz, 90 min) on gastric mucosal blood flow (GMBF), plasma corticosterone (COR) and catecholamines (CA), and gastric ulcer formation were investigated in relation to the effects of forced water-immersion stress (FWI) upon the same parameters. While WBV increased GMBF during the exposure, FWI decreased it both during and after the stress. No difference in the severity of ulcer formation between the WBV and the FWI groups was seen. Both WBV and FWI increased plasma COR and CA, although the degree of the increase in COR that accompanied WBV was less than that associated with FWI. Truncal vagotomy attenuated the reduction of GMBF and the extent of ulcer formation that occurred with FWI, but promoted a reduction of GMBF with WBV. These findings indicate that ulceration induced by WBV may be caused primarily by its direct and specific mechanical actions and not by indirect, central nervous system effects known to be important in the pathogenesis of ulcerations produced by mental stress.

Animals↗