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Biomedical subjects

H Shiraishi

Publications and source records attributed to H Shiraishi.

At least 19 recordsLinked to original sources
PubMed1999

A relationship between urine specific gravity and hyponatremia in hospitalized schizophrenic patients.

The relationship between urine specific gravity (USG) and the incidence of polydipsia/hyponatremia in hospitalized schizophrenic patients was examined. On the basis of five independent USG values, we identified 49% (35 out of 72) of male and 22% (8 out of 37) of female patients with hyposthenuria (mean USG < or = 1.008). Review of 2 years of records of routine laboratory examinations identified 12 males with hyponatremia, 11 males with borderline hyponatremia, and 49 males with normal values; among female patients, only one patient with hyponatremia and three patients with borderline values were identified. A significantly lower mean USG (1.003 +/- 0.001) for the male patients with hyponatremia compared with the male patients with normal serum sodium data (1.011 +/- 0.005) was observed. All of the male patients with hyponatremia, as well as 18 of the 49 male patients with normal serum sodium values, exhibited hyposthenuria. The USG values of all the patients with hyponatremia were consistently quite low (< or = 1.005), whereas 14 of the 18 normonatremia/hyposthenuria patients had normal USG values (i.e. > or = 1.009) in at least one of five determinations; the mean USG values for most (16 of 18) of the normonatremia/hyposthenuria patients ranged from 1.006 to 1.008. Thus, many hospitalized schizophrenic patients exhibit hyposthenuria of varying degrees, but consistently low USG values are most suggestive of the risk of polydipsia/hyponatremia.

Adult↗
PubMed1999

A conserved motif in group IC3 introns is a new class of GNRA receptor.

Terminal tetraloops consisting of GNRA sequences are often found in biologically active large RNAs. The loops appear to contribute towards the organization of higher order RNA structures by forming specific tertiary interactions with their receptors. Group IC3 introns which possess a GAAA loop in the L2 region often have a phylogenetically conserved motif in their P8 domains. In this report, we show that this conserved motif stands as a new class of receptor that distinguishes the sequences of GNRA loops less stringently than previously known receptors. The motif can functionally substitute an 11 nt motif receptor in the Tetrahymena ribozyme. Its structural and functional similarity to one class of synthetic receptors obtained from in vitro selection is observed.

Animals↗
PubMed1999

Trans-activation of the Tetrahymena group I intron ribozyme via a non-native RNA-RNA interaction.

The peripheral P2.1 domain of the Tetrahymena group I intron ribozyme has been shown to be non-essential for splicing. We found, however, that separately prepared P2.1 RNA efficiently accelerates the 3' splice-site-specific hydrolysis reaction of a mutant ribozyme lacking both P2.1 and its upstream region in trans. We report here the unusual properties of this trans-activation. Compensatory mutational analysis revealed that non-native long-range base-pairings between the loop region of P2.1 RNA and L5c region of the mutant ribozyme are needed for the activation in spite of the fact that P2.1 forms base-pairings with P9.1 in the Tetrahymena ribozyme. The trans -activation depends on the non-native RNA-RNA interaction together with the higher order structure of P2.1 RNA. This activation is unique among the known trans-activations that utilize native tertiary interactions or RNA chaperons.

Animals↗
PubMed1999

Dopamine D1 and D2 receptor agents and their interaction influence the synaptic density of the rat prefrontal cortex.

Recent findings indicate that some monoamines contribute to synaptic maintenance. We examined the synaptic density of the prefrontal cortex of rats with the single or combined administration of D1 and D2 antagonists and agonists. When each agent was administered individually, we observed a significant difference in synaptic density. This indicates that dopamine regulates synaptic maintenance. With the combined administration of antagonists or agonists at high dosages, a synergistic effect was observed. With the combined administration of a D1 antagonist and D2 agonist or a D1 agonist and D2 antagonist, a low dose of the D2 receptor drug enhanced the effect of the D1 receptor drug. The D1 receptor drug offset the effect of the high dose of D2 receptor drug, suggesting the possibility that the D1 receptor family is essential for synaptic maintenance.

Animals↗
PubMed1999

Fetus with long QT syndrome manifested by tachyarrhythmia: a case report.

We encountered a fetus who exhibited transient (at most 30 s), repeated episodes of tachyarrhythmia (240 bpm). This female neonate was born at 36 weeks of gestation and showed a markedly prolonged QT interval and transient, repeated episodes of polymorphic ventricular tachycardia. Congenital long QT syndrome was diagnosed. Retrospective analysis of the videotape showing fetal cardiac movement revealed that atrio-ventricular dissociation was present prenatally and thus, the fetal tachyarrhythmia was due to ventricular tachycardia. To our knowledge, there are few reports of a fetus with the long QT syndrome who exhibited ventricular tachycardia in utero. In the presence of unexplained fetal tachyarrhythmia, long QT syndrome should be considered as a possible underlying cause disorder. The presence of atrio-ventricular dissociation may be useful in prenatal diagnosis of long QT syndrome.

Adult↗
PubMed1999

Photoinduced electron transfer from synthetic chlorophyll analogue to fullerene C60 on carbon paste electrode. Preparation of a novel solar cell.

Upon a carbon paste electrode, fullerene C60 and successively methyl pyropheophorbide-a (chlorin) were casted to prepare a chlorin-fullerene modified carbon paste electrode (CFE). Photocurrents on the CFE were produced by irradiating of visible lights (> 510 nm) in an aqueous solution of 0.05 M ethylenediaminetetraacetic acid and 0.1 M Na2SO4 at pH 6.7. Larger anodic photocurrent was induced by the CFE than by the carbon paste electrodes modified with either the fullerene or the chlorin. In addition, the photocurrent of the CFE was dependent upon the amount of fullerene casted. The photocurrent action spectra of the CFE (at 300 mV vs. Ag/Ag+) showed that photoinduced electron transfer occurred from the excited state of the chlorin to the fullerene and/or from the chlorin to the photoexcited fullerene, and the electron of the fullerene anion radical produced was then shifted to the carbon paste. Upon irradiation of > 375 nm lights, the anodic photocurrent of the CFE was enhanced by increase in the illuminated light power and reached 0.03 mA cm-2 in the present system.

Carbon↗
PubMed1999

Pilot study of screening for Wilson disease using dried blood spots obtained from children seen at outpatient clinics.

Wilson disease (WD) is an autosomal recessive disorder of copper accumulation leading to liver and/or brain damage. In this paper, we describe the results of a pilot study of screening for WD using ceruloplasmin determinations in dried blood samples. Specimens were collected from children aged 1 to 6 years who were seen at local paediatric outpatient clinics in the Miyagi Prefecture. We measured ceruloplasmin (CP) concentrations in 2789 children using an enzyme-linked immunosorbent assay. The mean value was 12.4 +/- 3.95 mg/dl blood. Among these children, we identified two (case 1, male, 2 years old; case 2, female, 3 years old) with markedly reduced CP concentrations. Apart from low serum copper concentrations, their biochemical findings were almost normal, as were growth and development. To confirm the diagnosis, we analysed the WD gene and detected A803T/2871delC mutations in case 1 and R778L/G1035V mutations in case 2. We conclude that these children were presymptomatic WD patients. The CP level in dried blood samples from children aged 1 to 6 years appears to be a reliable marker for early detection of WD.

Ceruloplasmin↗
PubMed1999

Effects of chronic administration of interferon alpha A/D on serotonergic receptors in rat brain.

The effects of chronic administration of interferon (IFN; recombinant human IFN-alphaA/D) on serotonergic binding sites in rat brain were investigated. IFN was injected daily for 2 weeks at a dose of 100000 I.U./kg, (i.p.) in male Wistar rats. IFN did not alter either [3H]ketanserin binding to 5-HT2A receptors or [3H]paroxetine binding to 5-HT transporters. Scatchard analysis of [3H]8-hydroxy-dipropylaminotetraline (8-OH-DPAT) binding to 5-HT1A receptors demonstrated the presence of high- and low-affinity binding sites in both treatment and control groups. IFN significantly increased both Kd and Bmax measures of [3H]8-OH-DPAT binding at low-affinity binding sites, but not at the high-affinity sites. These results suggest that IFN affects the low-affinity 5-HT1A receptors sites and may be involved in the development of IFN-induced psychiatric disturbances.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1999

An autopsy case of myotonic dystrophy with mental disorders and various neuropathologic features.

An autopsy case of myotonic dystrophy (MD) is reported. The patient was a 58-year-old male. He presented with muscular weakness and muscular atrophy at the age of 33 and was diagnosed as having MD from myotonic symptoms (i.e. percussion and grip myotonia) at 49 years old. Mental disorders including a delusional hallucinatory state, mental slowness, indifference, and lack of spontaneity as well as visual cognitive impairments were noted at the age of 55. He showed Parkinsonism and died of septic shock. T2-weighted magnetic resonance imaging demonstrated diffuse cortical atrophy with a marked frontal atrophy and high-intensity signals in the white matter. Single photon emission computed tomography demonstrated hypoperfusion in the frontal cortex. Neuropathologic observation revealed neuronal loss in the superficial layer of the frontal and parietal cortices and extensive neuronal loss in the occipital cortex, intracytoplasmic inclusion body in the nerve cell of the medial thalamic nuclei, neuronal loss and presence of Lewy bodies in the substantia nigra and locus ceruleus corresponding to the pathologic features of Parkinson's disease, as well as abnormalities of myelin in the white matter. The present case suggests that in MD brain, various neuropathologic changes may occur and they contribute to the mental disorders.

Basal Ganglia↗
PubMed1999

Hemodynamic effect of rapid atrial pacing in fetal lambs.

To determine the threshold at which rapid atrial pacing brings on fetal circulatory failure, we made a fetal supraventricular tachyarrhythmia model and measured the central venous pressure, aortic pressure, and right and left ventricular outputs in five fetal lambs. Under maternal anesthesia, the uterus was opened, and under local anesthesia, polyvinyl catheters were inserted into the fetal superior vena cava and ascending aorta through a neck incision. Pacing leads (Medtronic model 6492) were then sutured onto the fetal right atrial appendage via right thoracotomy. Ventricular output was estimated using a Toshiba SSH-65A echocardiography by a transuterine approach. Fetal hemodynamics were observed without pacing (control), and at the atrial pacing rates of 200, 300, 350, and 400/min. Central venous pressure (CVP) increased and the aortic pressure decreased when the right atrium was paced at 350/min or more. Right ventricular output decreased when the right atrium was paced at 300/min or more. The left ventricular output, however, remained constant. The right ventricular output was 382 +/- 106 mL/kg/min at control, and 391 +/- 117 mL/kg/min when paced at 200/min, but decreased to 210 +/- 138 mL/kg/min when paced at 300/min, to 223 +/- 102 mL/kg/min when paced at 350/min, and to 186 +/- 86 mL/kg/min when paced at 400/min. Fetal circulatory failure occurred when the right atrium was paced at 300/min or more.

Animals↗
PubMed1999

[Differential diagnosis of schizophrenic symptoms complicated with brain anomalies including bilateral temporal arachnoid cysts by eye mark recorder and PET: a case study].

Bilateral temporal arachnoid cysts and other intracranial congenital lesions including a moderately large left temporal arachnoid cyst accompanied by remarkable dysplasia of the temporal lobe in particular were discovered by chance during computerized axial tomography of a 26-year-old Japanese male who had been diagnosed as schizophrenia approximately 10 years earlier. A detailed re-assessment revealed no other organic symptoms or signs. His symptoms and clinical course met the DSM-IV criteria for schizophrenia, disorganized type. Based on his symptoms, positron emission tomography (PET) and the eye-movement recording test developed by Kojima et al. were performed. In addition, psychological tests including WAIS, Rorschach Test, and Wechsler's Memory Test were administered for further differential diagnosis. PET using continuous inhalation of oxygen 15-gas revealed a regional decrease in CBF and CMRO2 in the superior medial frontal lobe including the anterior cingulate gylus, findings sometimes associated with schizophrenia. However, no abnormal findings were noted around the arachnoid cysts. In the eye-movement recording test, several parameters including the responsive search score (RSS) were about the same level as that commonly observed in schizophrenics and are classified as schizophrenia by discrimination analysis. The psychological tests offered no reason to doubt the diagnosis of schizophrenia. Thus, the patient was diagnosed as schizophrenia with arachnoid cysts and other intracranial lesions. The way of diagnosis we used here might bring forth a breakthrough in schizophrenia research by differentiating schizophrenia from the other organic brain diseases.

Adult↗
PubMed1999

Effects of placental chorionicity on outcome in twin pregnancies. A cohort study.

OBJECTIVE: To examine the effects of the chorionicity of the placenta on infant outcome at 1 year of age in twin pregnancies. STUDY DESIGN: Cohort study and retrospective review of the medical records of 44 monochorionic (MC) and 164 dichorionic (DC) twin gestations that had been followed at our institution since < 20 weeks' gestation. Physical and neurologic status was assessed at 1 year of corrected age in infants born to these 208 women. RESULTS: Adverse infant outcomes, such as death, cerebral palsy and mental retardation, occurred in 9 (10%) of 88 MC infants (4 deaths and 5 disabled infants) as compared with 12 (3.7%) of 328 DC infants (6 deaths and 6 disabled infants) (P < .05). Although delivery occurred one week earlier in MC than in DC twins (34.7 +/- 2.8 vs. 35.7 +/- 2.3 weeks, P < .01), there was no significant difference in gestational age at birth or birth weight between the 9 MC and 12 DC infants with adverse outcomes. A presumptive antenatal diagnosis of twin-twin transfusion syndrome (TTTS) was made in 14 (32%) of the 44 MC twin gestations. TTTS was considered to be responsible for adverse outcome in 7 MC infants. All 9 MC infants with adverse outcomes and 4 (33%) of 12 DC infants with adverse outcomes belonged to pairs that had weight discordance > or = 25% (P < .01). CONCLUSION: MC twins had an increased risk of adverse outcomes as compared with DC twins, mainly because of TTTS. In both MC and DC twins, a birth weight discordance > or = 25% was associated with adverse infant outcomes. The number of infants with disabilities at 1 year of age was equal to the number of deaths.

Adult↗
PubMed1998

Synaptic density of the prefrontal cortex regulated by dopamine instead of serotonin in rats.

Recent findings indicate that monoamine contributes to synaptic plasticity. We examined the synaptic density of the prefrontal cortex and parietal cortex of rats using dopamine (DA) antagonists and agonists, as well as serotonin (5-HT) depleters and found a reduction in synaptic density in the prefrontal cortex lamina V-VI at a maximum of 20% with administration of a D1 antagonist (SCH23390) and at a maximum of 30% with a D2 antagonist (YM09151). Further, with the administration of D1+D2 antagonists there was a 27% decrease in synaptic density, which was a larger reduction than the total of the single dosages of each DA antagonist at equal levels. Increase in synaptic density was seen at a maximum of 8.5% with dosage of a D1 agonist (SKF38390) and 14.5% with dosage of a D2 agonist (PPHT). The dosage of D1+D2 agonists showed a 27.1% increase in synaptic density. There was no change in synaptic density of the parietal cortex with either DA antagonist or agonist administration. Administration of 5-HT depleter pCPA resulted in a 13.8% reduction of synaptic density in the parietal cortex, though there was no change identified in the synaptic density in the prefrontal cortex. Based on these results, it was suggested that the area of the brain with affected synaptic plasticity could differ, depending on the type of monoamine.

Animals↗
PubMed1998

Roles of the C-terminal domains of human dihydrodiol dehydrogenase isoforms in the binding of substrates and modulators: probing with chimaeric enzymes.

Human liver dihydrodiol dehydrogenase (DD; EC 1.3.1.20) exists in isoforms (DD1, DD2 and DD4) composed of 323 amino acids. DD1 and DD2 share 98% amino acid sequence identity, but show lower identities (approx. 83%) with DD4, in which a marked difference is seen in the C-terminal ten amino acids. DD4 exhibits unique catalytic properties, such as the ability to oxidize both (R)- and (S)-alicyclic alcohols equally, high dehydrogenase activity for bile acids, potent inhibition by steroidal anti-inflammatory drugs and activation by sulphobromophthalein and clofibric acid derivatives. In this study, we have prepared chimaeric enzymes, in which we exchanged the C-terminal 39 residues between the two enzymes. Compared with DD1, CDD1-4 (DD1 with the C-terminal sequence of DD4) had increased kcat/Km values for 3alpha-hydroxy-5beta-androstanes and bile acids of 3-9-fold and decreased values for the other substrates by 5-100-fold. It also became highly sensitive to DD4 inhibitors such as phenolphthalein and hexoestrol. Another chimaeric enzyme, CDD4-1 (DD4 with the C-terminal sequence of DD1), showed the same (S)-stereospecificity for the alicyclic alcohols as DD1, had decreased kcat/Km values for bile acids with 7beta- or 12alpha-hydroxy groups by more than 120-fold and was resistant to inhibition by betamethasone. In addition, the activation effects of sulphobromophthalein and bezafibrate decreased or disappeared for CDD4-1. The recombinant DD4 with the His314-->Pro (the corresponding residue of DD1) mutation showed intermediate changes in the properties between those of wild-type DD4 and CDD4-1. The results indicate that the binding of substrates, inhibitors and activators to the enzymes is controlled by residues in their C-terminal domains; multiple residues co-ordinately act as determinants for substrate specificity and inhibitor sensitivity.

Amino Acid Sequence↗
PubMed1998

Novel mutations in the promoter and coding region of the human 5-HT1A receptor gene and association analysis in schizophrenia.

Dysfunction of serotonin systems has been implicated in schizophrenia. In the present study, the human 5-HT1A receptor gene containing the 5' untranslated region was screened in order to detect genetic variations, through which alteration of protein function or level of expression might contribute to schizophrenia. Genomic DNAs were isolated from whole-blood samples of 61 unrelated schizophrenic patients and 100 healthy controls. Genetic variations were screened systematically by single-strand conformational polymorphism (SSCP) analysis, followed by direct sequencing of polymerase chain reaction (PCR) product as well as restriction fragment-length polymorphism (RFLP). The novel mutations (-51T --> C, -152C --> G, -321G --> C, -480delA, and -581C --> A) were found in the 5' untranslated region. Furthermore, we found a novel missense mutation (Gly272Asp) in the coding region in addition to the mutations (Pro16Leu, 294G --> A, and 549C --> T) reported previously. No significant differences in genotype frequencies as well as allele frequencies were found between patients and controls. Our data provided no evidence of association between schizophrenia and the variants in the 5' untranslated region as well as the coding region of the human 5-HT1A receptor gene.

Genetic Markers↗