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Biomedical subjects

T Yoshikawa

Publications and source records attributed to T Yoshikawa.

At least 199 records · Page 11Linked to original sources
PubMed2000

Two-dimensional thick-slice MR digital subtraction angiography for assessment of cerebrovascular occlusive diseases.

Although spatial resolution of current MR angiography is excellent, temporal resolution has remained unsatisfactory. We evaluated clinical applicability of 2D thick-slice, contrast-enhanced subtraction MR angiography (2D-MR digital subtraction angiography) with sub-second temporal resolution in cerebrovascular occlusive diseases. Twenty-five patients with cerebrovascular occlusive diseases (8 moyamoya diseases, 10 proximal internal carotid occlusions, and 2 sinus thromboses ) were studied with a 1.5-T MR unit. The MR digital subtraction angiography (MRDSA) was performed per 0.97 s continuously just after a bolus injection of 15 ml of gadolinium chelates up to 40 s in sagittal (covering hemisphere) or coronal planes. Subtraction images were generated at a workstation. We evaluated imaging quality and hemodynamic information of MRDSA in comparison with those of routine MR imaging, non-contrast MR angiography, and X-ray intra-arterial DSA. Major cerebral arteries, all of the venous sinuses, and most tributaries were clearly visualized with 2D MRDSA. Also, pure arterial phases were obtained in all cases. The MRDSA technique demonstrated prolonged circulation in sinus thromboses, distal patent lumen of proximal occlusion, and some collateral circulation. Such hemodynamic information was comparable to that of intra-arterial DSA. Two-dimensional thick-slice MRDSA with high temporal resolution has a unique ability to demonstrate cerebral hemodynamics equivalent to that of intra-arterial DSA and may play an important role for evaluation of cerebrovascular occlusive diseases.

Adult↗
PubMed2000

Time-resolved two-dimensional thick-slice magnetic resonance digital subtraction angiography in assessing brain tumors.

The aim of this study was to evaluate clinical applicability of two-dimensional (2D) thick-slice, contrast-enhanced magnetic resonance digital subtraction angiography (MRDSA) with high temporal resolution in diagnosis of brain tumors. Forty-four patients with brain tumors including, 15 meningiomas, 8 gliomas, 6 metastatic tumors, 4 neuromas, and 2 hemangioblastomas, were studied with 2D MRDSA with frame rate approximately 1 s. Images were continuously obtained following the initiation of bolus injection of gadolinium chelates for 40 s and subtraction images were generated in a workstation. We evaluated visualization of normal cranial vessels on MRDSA and compared MRDSA and intra-arterial digital subtraction angiography (IADSA) with regard to hemodynamic information. Large cerebral arteries, all venous sinuses, and most tributaries were clearly visualized. A stain was present in hypervascular tumors including all 15 meningiomas and 2 hemangioblastomas on MRDSA. Presence of a stain demonstrated on MRDSA and that on IADSA coincided in 16 of 20 cases (Spearman rank correlation value was 0.85). The location, shape, and phase of the stain on MRDSA were similar to those on IADSA. Two-dimensional MRDSA with high temporal resolution has a unique ability to demonstrate cerebral hemodynamics, such as IADSA, and can play an important role in assessing brain tumors.

Adolescent↗
PubMed2000

Simultaneous display of MRA and MPR in detecting vascular compression for trigeminal neuralgia or hemifacial spasm: comparison with oblique sagittal views of MRI.

A new technique, simultaneous display of magnetic resonance angiography (MRA) and multiplanar reconstruction (MPR), was performed by a workstation to identify the involved vessels in patients with trigeminal neuralgia (TN) or hemifacial spasm (HFS), and the results were compared with those of oblique sagittal MRI technique. Twelve patients with either HFS or TN were prospectively assessed by simultaneous display of MRA and MPR, and oblique sagittal techniques, to point out the neurovascular compression and to identify the involved vessels. Three-dimensional (3D) time-of-flight (TOF) spoiled gradient-echo (SPGR) images were acquired to create MRA and MPR. Oblique sagittal views were also created and displayed on films. A total of 15 vessels in 12 patients were identified as compressing vessels during surgery. Simultaneous display of MRA and MPR technique pointed out the presence of vessels at and/or around root entry/exit zone (REZ) in all 12 patients, but proper identification by the name of the individual vessel was correct in 13 of 15 cases. However, oblique sagittal technique indicated the presence of vessels at and/or around REZ in 11 patients, but only 8 of 14 vessels were correctly identified. Our new method, simultaneous display of MRA-MPR, facilitated correct identification of the involved vessels compared with the oblique sagittal view method.

Hemifacial Spasm↗
PubMed2000

Colocalization of pinopsin with two types of G-protein alpha-subunits in the chicken pineal gland.

Pinopsin is a photoreceptive molecule present in the outer segments of chicken pinealocytes. In this paper, the localization of alpha-subunits of G-proteins, rod transducin (Gt1) and Gq/11, was examined by immunoelectron microscopy to investigate whether these G-proteins colocalize with pinopsin in the outer segments. Ultrathin sections of the chicken pineal gland were double-immunolabeled with antibodies to pinopsin and either Gt1alpha or Gq/11alpha. As shown previously, the outer segments around the follicular lumen exhibited divergent morphology with ciliary, bulbous, or lamellate shapes, and most of them displayed pinopsin immunoreactivity. The majority (>90%) of pinopsin-immunopositive outer segments were labeled by anti-Gt1alpha and/or anti-Gq/11alpha antibodies. Application of double-immunolabeling to serial sections demonstrated that a large number of the pinopsin-immunopositive outer segments contained both Gt1alpha and Gq/11alpha immunoreactivities. These results suggest that Gt1alpha and Gq/11alpha are functionally coupled with light-activated pinopsin within a single outer segment.

Animals↗
PubMed2000

Changes in hemodynamic variables and catecholamine levels after rapid increase in sevoflurane or isoflurane concentration with or without nitrous oxide under endotracheal intubation.

PURPOSE: Rapid increases in concentrations of isoflurane and desflurane in oxygen have been shown to increase sympathetic activity. The aim of this study was to determine whether concomitant administration of nitrous oxide would reduce these sympathomimetic effects of volatile anesthetics. METHODS: Eighty healthy patients in whom the trachea was intubated and mechanically ventilated were given 15 min of anesthesia with either N(2)O (67%)-O(2)-sevoflurane (GOS), O(2)-sevoflurane (OS), N(2)O (67%)-O(2)-isoflurane (GOI), or O(2)-isoflurane (OI) (n = 20 per group). The inspired concentration of sevoflurane was 0.85% (0.5 minimum alveolar concentration [MAC]), and that of isoflurane was 0.6% (0.5 MAC). Fifteen minutes after endotracheal intubation, baseline and arterial blood sample data were obtained. Immediately after that, a sudden administration of 2.9 MAC volatile anesthetics was performed. Systolic and diastolic arterial pressures, heart rate, and end-tidal carbon dioxide concentration were obtained at 0.5, 1, 1.5, 2, 3, 4, and 5 min after that. To measure catecholamine levels, arterial blood samples were obtained 2 and 5 min after the trial started. RESULTS: Except for the OI group, systolic and diastolic arterial pressure progressively decreased after the abrupt increase in the concentration of volatile anesthetics. Except for the OS group, the heart rate increased after the abrupt increase in the concentration of volatile anesthetics. In the OI group, the end-tidal concentration of carbon dioxide increased at 0.5 and 1 min, suggesting that a slight hyperdynamic state occurred. However, it decreased progressively after the abrupt increase in volatile anesthetic concentration in the other groups. Plasma norepinephrine levels increased progressively in all groups. CONCLUSION: Even if nitrous oxide was added to isoflurane or sevoflurane, the increase in heart rate could not be avoided. Contrary to previous reports, severe hyperdynamic circulation was not observed after a rapid increase in isoflurane concentration.

Journal Article↗
PubMed2000

An association study between two missense variations of the benzodiazepine receptor (peripheral) gene and schizophrenia in a Japanese sample.

The benzodiazepine receptor (peripheral) (BZRP) mainly localized on glial cells plays a role in neurosteroid synthesis, and increases with glial proliferation. We have recently reported a significant decrease in the density of BZRP labeled by [3H] PK 11195 in the postmortem brain of chronic schizophrenics, suggesting that dysfunctions of the BZRP are involved in the pathophysiology of schizophrenia. We screened 11 patients with schizophrenia and 10 controls, which were used in a previous postmortem study, for their genomic sequences of the BZRP gene in order to find DNA sequence variations. One novel missense polymorphism (His162Arg) and another previously reported missense mutation (Ala147Thr) were detected. An association study of the identified variations was then performed in an extended Japanese sample of 304 schizophrenic patients and 369 controls. While there was an increased tendency in the frequency of the 162Arg allele of schizophrenics compared to that of the controls (p = 0.0603), no statistically significant association with schizophrenia was observed in the Ala147Thr allele (p = 0.1016). These results do not suggest that the two missense polymorphisms play a major role in the genetic predisposition of schizophrenia in the Japanese sample.

Adult↗
PubMed2000

cDNA cloning, tissue expression, and chromosome mapping of human homolog of SOX18.

The SRY (sex-determining region Y) gene encodes a transcription factor characterized by a DNA-binding motif termed the HMG (high mobility group) domain. The SOX (Sry-box) genes comprise a large family related by homology to the HMG-box region. We isolated a cDNA clone with an open reading frame encoding a putative protein of 384 amino acids, which shared 83% identity to the mouse Sox18 protein. Northern blot analysis revealed that a 1.9-kb band of human SOX18 messenger RNAs was predominantly expressed in heart, although weak signals were seen in brain, liver, testis, and leukocyte. By polymerase chain reaction (PCR)-based analyses with both a human/rodent monochromosomal hybrid cell panel and a radiation hybrid panel, the gene was mapped to the chromosome 20q13.33 region.

Amino Acid Sequence↗
PubMed2000

cDNA cloning of a human RAB26-related gene encoding a Ras-like GTP-binding protein on chromosome 16p13.3 region.

Members of the RAB protein family are important regulators of vesicular fusion and trafficking. A putative new member of the RAB family of genes was identified through a public database search, and its full-length cDNA was isolated from a human fetal brain cDNA library. The predicted protein product of the gene consists of 190 amino acid residues and has 87% identity with rat Rab26. Thus, we designated this gene as the human RAB26-related gene. Reverse transcription-coupled polymerase chain reaction (RT-PCR) demonstrated that the RAB26-related messenger RNA was predominantly expressed in adult and fetal brain. Furthermore, an RT-PCR experiment for brain subregions showed that the mRNA was highly expressed in the amygdala, cerebellum, caudate nucleus, and hippocampus. By PCR-based analysis with both a human/rodent monochromosomal hybrid cell panel and a radiation hybrid panel, the gene was mapped to the chromosome 16p13.3 region between markers WI-7742 and WI-3061. The RAB26-related gene consists of eight exons that span about 44kb of the genome DNA.

Amino Acid Sequence↗
PubMed2000

cDNA cloning of a new member of the Ras superfamily, RAB9-like, on the human chromosome Xq22.1-q22.3 region.

Members of the RAB protein family regulate vesicular trafficking and reside in specific intercellular compartments. A new member of the RAB family was identified through a public database search, and its full-length cDNA was isolated from a human fetal brain cDNA library. The predicted protein product of the gene consists of 201 amino acid residues, and the protein has 86% similarity to human RAB9 at the amino acid level. We designated the new gene RAB9-like. Northern blot analysis showed that the gene was transcribed ubiquitously in various human tissues. A database search revealed that the gene is divided into three exons and spans approximately 7.2kb of the genome DNA of chromosome Xq22.1-q22.3 region.

Amino Acid Sequence↗
PubMed2000

Impact of Doppler-derived left ventricular diastolic performance on exercise capacity in normal individuals.

BACKGROUND: Doppler-derived left ventricular (LV) diastolic indexes have been shown to correlate with exercise capacity in patients with heart diseases as well as healthy individuals. However, it is uncertain whether they predict exercise capacity independent of noncardiac factors. METHODS: To clarify the impact of the LV diastolic index on exercise capacity, 160 healthy individuals were investigated. All underwent Bruce protocol treadmill stress testing and 2-dimensional and Doppler echocardiography. Estimated metabolic equivalent was calculated from exercise time (metabolic equivalent = 1.11 + 0.016 x exercise time). Diastolic performance was assessed by Doppler transmitral flow velocity pattern. Pulmonary function tests and complete blood cell count were also performed. RESULTS: LV diastolic indexes correlated well with metabolic equivalent (peak transmitral filling velocity (A): r = -0.51, P <.0001; ratio of early and late transmitral filling velocities (E/A): r = 0.58, P <. 0001). However, there was no significant correlation between LV systolic indexes and metabolic equivalent. Independent predictors for a higher metabolic equivalent by multivariate analysis were higher E/A (P <.0001), higher vital capacity (P =.001), smaller body mass index (P =.0003), younger age (P =.0050), and higher hemoglobin concentration (P =.0026). CONCLUSION: Doppler-derived LV diastolic index may help in predicting exercise capacity in normal individuals independent of other cardiac and extracardiac factors.

Adult↗
PubMed2000

Flavonoid constituents from Glycyrrhiza glabra hairy root cultures.

An unusual biflavonoid named licoagrodin was isolated from the hairy root cultures of Glycyrrhiza glabra (Leguminosae) along with three prenylated retrochalcones, licoagrochalcones B, C, D, a prenylated aurone, licoagroaurone and four known prenylated flavonoids, licochalcone C, kanzonol Y, glyinflanin B and glycyrdione A. From the glycosidic fraction, a isoflavone glycoside, licoagroside A, and a maltol glycoside, licoagroside B were isolated together with four known isoflavone glycosides, two flavone C-glycosides, and three other glycosides. Their structures were elucidated on the basis of spectroscopic evidence.

Chalcones↗
PubMed2000

Purification and characterization of UDP-glucuronate: baicalein 7-O-glucuronosyltransferase from Scutellaria baicalensis Georgi. cell suspension cultures.

UDP-glucuronate: baicalein 7-O-glucuronosyltransferase (UBGAT) catalyzes the transfer of glucuronic acid from UDP-glucuronic acid to the 7-OH of baicalein. UBGAT was purified from cultured cells of Scutellaria baicalensis Georgi (Lamiaceae). It was purified 95-fold using various chromatography and chromatofocusing procedures to apparent homogeneity. The Mr was estimated to be 110 kDa by gel filtration chromatography with a 52 kDa subunit by SDS-PAGE. The isoelectric point was pH 4.8. UBGAT was specific to UDP-glucuronic acid as a sugar donor and flavones with substitution ortho- to the 7-OH group such its baicalein (6-OH), scutellarein (6-OH) and wogonin (8-OMe).

Chromatography, Gel↗
PubMed2000

Gq protein level increases concurrently with antigen-induced airway hyperresponsiveness in rats.

In the present study, bronchial Gq protein level of the airway hyperresponsive rats was determined by using immunoblot analysis. In the airway hyperresponsive rats that were sensitized and repeatedly antigen challenged, the in vitro bronchial responsiveness to acetylcholine was significantly enhanced as compared with that in the sensitized control group. Moreover, the bronchial contraction induced by 10 microM AlF(4)(-) (generated by 10 microM AlCl(3) plus 10 mM NaF) was significantly elevated after repeated antigen challenge (0.44+/-0.13 and 1.09+/-0.09 g tension in the control and airway hyperresponsive groups, respectively; P<0.01). In both groups, immunoblotting with the antibody against G alpha q gave a single 42 kD band. The G alpha q protein levels in the airway hyperresponsive group (0.58+/-0.12) estimated by G alpha q/beta-actin ratio was significantly greater than those in the control group (0.30+/-0.10; P<0.05). These findings suggest that the increase in G alpha q protein level may be involved in the pathogenesis of antigen-induced airway hyperresponsiveness in rats.

Animals↗
PubMed2000

WFS1 gene mutation search in depressive patients: detection of five missense polymorphisms but no association with depression or bipolar affective disorder.

BACKGROUND: Wolfram syndrome (WFS) is an autosomal recessive neurodegenerative disorder. Recently, the WFS1 gene was isolated, and approximately 80% of the mutations responsible for WFS were found in exon 8 of WFS1. It has been noted that heterozygous carriers of the WFS gene are 26-fold more likely to be hospitalized for depression, and it has been estimated that approximately 25% of all people hospitalized for depression may carry the WFS gene(s). METHODS: We searched for mutations in exon 8 of WFS1 in 30 depressive patients with a history of hospitalization and whose age at onset was under 40 years. We also examined 47 bipolar affective patients and 62 control subjects for an association. RESULTS: A were detected. Four of the six were novel. No nonsense or frameshift mutation was detected. Genotypic and allelic distributions were similar between the depressive patients and the controls. No association with bipolar affective disorder was suggested. LIMITATIONS: Because of the small sample size, the probability of finding at least one patient with WFS-responsible mutation(s) was 70% if depression is associated with WFS1 mutation(s) in 5% of patients. CONCLUSION: It is not likely that WFS1 mutations are responsible for as much as 25% of depressive illness.

Adult↗
PubMed2000

Effect of the natural antioxidant 2"-O-glycosylisovitexin on superoxide and hydroxyl radical generation.

The inhibitory effect of 2"-O-glycosyl isovitexin (2"-O-GIV) isolated from green barley leaves on superoxide and hydroxyl radical generation was investigated using electron spin resonance spectroscopy. 2"-O-GIV exhibited dose-related inhibitory activity both towards superoxide generation and hydroxyl radical generation. 2"-O-GIV inhibited superoxide formation by 97% at a level of 25 mM and inhibited hydroxyl radical formation by 91% at a level of 500 microM. The results suggest that the inhibitory activity of 2"-O-GIV is due to trapping radicals.

Antioxidants↗