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T Araki

Publications and source records attributed to T Araki.

At least 253 records · Page 14Linked to original sources
PubMed1998

Postischemic changes of

Sequential alterations of [3H]nimodipine and [3H]ryanodine binding in gerbils were investigated in selectively vulnerable regions, such as the striatum and hippocampus, 1 h to 7 days after 10 min of transient cerebral ischemia. [3H]Nimodipine binding showed no significant changes in the striatum and hippocampus up to 48 h after ischemia. Seven days after ischemia, however, a severe reduction in [3H]nimodipine binding was observed in the dorsolateral striatum, hippocampal CA1 (stratum oriens, stratum pyramidale and stratum radiatum) and hippocampal CA3 sector. On the other hand, [3H]ryanodine binding showed a significant increase in the hippocampus 1 h after ischemia. Five hours after ischemia, a significant reduction in [3H]ryanodine binding was observed only in the hippocampal CA1 sector. Thereafter, the striatum and hippocampus showed no significant alterations in [3H]ryanodine binding up to 48 h after ischemia. After 7 days, a marked reduction in [3H]ryanodine binding was observed in the striatum and hippocampus which were particularly vulnerable to ischemia. These results demonstrate that postischemic alteration in [3H]nimodipine and [3H]ryanodine binding is produced with different processes in the hippocampus. They also suggest that the mechanism for striatal cell damage caused by transient cerebral ischemia may, at least in part, differ from that for hippocampal neuronal damage. Furthermore, our findings suggest that abnormal calcium release from intracellular stores may play a pivotal role in the development of hippocampal neuronal damage. Copyright Rapid Science Ltd

Journal Article↗
PubMed1998

PET study of striatal fluorodopa uptake and dopamine D2 receptor binding in a patient with juvenile parkinsonism.

We studied pre-synaptic and post-synaptic function in the striatum of a patient with juvenile parkinsonism (JP) using positron emission tomography (PET). [18F]6-fluorodopa (18FDOPA), 11C-YM-09151-2 and [18F]fluoro-2-deoxy-d-glucose (18FDG) were used to measure fluorodopa uptake, dopamine D2 receptor binding and glucose metabolism, respectively. In this patient, 18FDOPA accumulation was decreased markedly in the caudate nucleus and the putamen bilaterally. In the images of 11C-YM-09151-2 and 18FDG, in contrast, no conspicuous changes were observed in the striatum. Thus our PET studies using 18FDOPA, 11C-YM-09151-2 and 18FDG provide a useful approach for assisting the diagnosis of JP, because the present findings are different from the results in patients with dopa-responsive dystonia and hereditary progressive dystonia with marked diurnal fluctuation. Furthermore, our findings are of particular interest in relation to the pathogenesis of JP.Copyright Lippincott-Raven Publishers

Journal Article↗
PubMed1998

Effect of NG-nitro-L-arginine methyl ester, a nitric oxide synthase inhibitor, on neurotransmitter receptor systems in aged rats.

In order to examine the effect of age and nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), we studied the changes on major neurotransmitter receptor systems in 6 (adult) and 24-month-old (aged) Fischer male rats using receptor autoradiography. L-NAME was administrated intraperitoneally in aged rats once a day for 4 weeks. [3H]QNB (quinuclidinyl benzilate), [3H]HC (hemicholinium-3), [3H]muscimol, [3H]SCH 23390 ([N-methyl-3H]R[+]-8-chloro-2,3,4,5-tetrahydro-3-methyl-5-phenyl-7-ol-benzazepine), [3H]nemonapride and [3H]mazindol were used as markers of muscarinic acetylcholine receptors, high-affinity choline uptake sites, GABAA (gamma-aminobutyric acidA) receptors, dopamine D1 receptors, dopamine D2 receptors and dopamine uptake sites, respectively. The age-related change in [3H]muscimol binding in the brain was more pronounced than that in [3H]QNB, [3H]HC, [3H]SCH 23390, [3H]nemonapride and [3H]mazindol binding. Chronic treatment (4 weeks) with L-NAME caused no significant changes in [3H]QNB, [3H]muscimol, [3H]SCH 23390 and [3H]nemonapride binding in most areas of aged rat brain, as compared with vehicle-treated aged animals. However, chronic treatment with L-NAME caused a significant reduction in [3H]HC and [3H]mazindol binding in any brain regions of aged rats in comparison with the vehicle-treated aged animals. These results demonstrate that the GABAergic system is more susceptible to aging processes than cholinergic and dopaminergic systems in the brain. Furthermore, our findings suggest that nitric oxide may play some role in the regulation of choline uptake and dopamine uptake systems during aging processes. Copyright 1998 Lippincott Williams & Wilkins

Journal Article↗
PubMed1998

Detection rate of the cervical gland area during pregnancy by transvaginal sonography in the assessment of cervical maturation.

OBJECTIVES: To detect the cervical gland area during normal pregnancy, and to determine its detection rate and relationship with cervical maturation. DESIGN: This was a mixed longitudinal and cross-sectional sonographic study involving a total of 514 transvaginal scans performed for detection of cervical gland area and measurement of cervical length in 260 normal singleton pregnancies at 16-41 weeks of gestation. The conventional cervical maturation index was measured simultaneously by digital examination. RESULTS: The detection rate of cervical gland area remained practically constant until the 31st week of pregnancy, but significantly decreased thereafter. Highly significant correlations were noted between the detection rate of cervical gland area and cervical length, cervical gland area and cervical maturation index, and cervical length and cervical maturation index. CONCLUSIONS: This study showed for the first time that cervical gland area can be detected sonographically and that its absence might be a predictor of preterm labor.

Adolescent↗
PubMed1998

Subcellular localization of myosin I in A10 smooth muscle cell.

We isolated and identified a 110-kDa myosin I from porcine aorta media smooth muscle [Y. Hasegawa et al. (1996) J. Biochem. 120, 971-976]. Partial peptide sequences of the 110-kDa myosin I fragments were homologous to amino acid sequences deduced from myosin Ibeta of bovine brain and adrenal gland. We investigated biochemically the distribution of the 110-kDa myosin I by cell fractionation methods. About 10% of myosin I present in whole cells could be extracted by treatment with 0.02% saponin, which does not liberate organelles, indicating that at least 10% of myosin I present in A10 cells is associated with neither organelles nor cytoskeleton. After treatment of A10 cells with 0.5% Triton X-100, the insoluble cytoskeleton contained 45% of myosin I present in whole cells. Treatment with MgATP extracted most of myosin I from the cytoskeleton, indicating that the distribution of myosin I is maintained by binding of the myosin I head to an actin filament. On the other hand, when the cell homogenate was fractionated on sucrose density step gradients, about 80% of myosin I was associated with membranes of various densities. An attempt to dissociate the myosin I from the membranes in the presence of MgATP was not successful. These results show that about 80% of total myosin I is associated directly with membranes, not through F-actin. The amounts of myosin I associated with membranes or cytoskeleton provide evidence that myosin I in A10 cells is associated in part with only membrane and in part with both cytoskeleton and membranes. Our results lead to conclusion that myosin I exist in several states: membrane-and-cytoskeleton-associated, membrane-associated, and membrane-and-cytoskeleton-free. These states may be in dynamic equilibrium, allowing myosin I to respond to the cellular requirements.

Amino Acid Sequence↗
PubMed1998

Detection of lung lesions and lymph nodes with 201Tl SPET.

The aim of this study was to characterize lung lesions by means of the uptake, retention and washout of 201Tl, and to quantify the sensitivity of 201Tl SPET (single photon emission tomography) in detecting mediastinal and hilar lymph nodes. A total of 68 patients with lung lesions (tumours and inflammation) underwent both helical computed tomography (CT) and 201Tl SPET examinations. Uptake, retention and washout parameters were calculated from early and delayed 201Tl SPET by drawing regions of interest over the primary lesion and the background of the lung. The findings on 201Tl SPET were compared with those on CT and surgical findings. A significant difference in the retention index (RI) was observed between primary malignant and benign lesions. In detecting lymph nodes, the sensitivity, specificity and negative predictive value were 83%, 60% and 90% respectively for early 201Tl SPET, and 50%, 80% and 80% respectively for delayed 201Tl SPET. 201Tl SPET with semi-quantitative analysis, especially RI, helps to differentiate between malignant and benign lung lesions. Lymph nodes larger than 1 cm on CT but not showing 201Tl uptake could be considered non-metastatic lesions.

Adult↗
PubMed1998

Detection of lung and chest tumours using 99Tcm-tetrofosmin: comparison with 201Tl.

The aim of this study was to assess the usefulness of 99Tcm-tetrofosmin for detecting tumours of the lungs and adjacent structures and to compare the results with those for 201Tl. In the 18 patients studied, there were 30 lesions in total. Dual-isotope SPET acquisitions were performed 10 min and 3 h after the administration of 99Tcm-tetrofosmin and 201Tl. Image quality and semi-quantitative parameters were evaluated for both tracers. All lesions were detected by the two radiopharmaceuticals on both the early and delayed images. In seven patients, the image quality of 99Tcm-tetrofosmin was better than that of 201Tl. For the detection of metastatic lymph nodes, the delayed 201Tl and the early 99Tcm-tetrofosmin images were superior. No significant difference was observed between the uptake ratios of the two tracers. 99Tcm-tetrofosmin showed significantly (P < 0.001) higher washout than 201Tl from both the lesions and normal lungs, although washout of 201Tl from normal lungs was significantly higher than that from the lesions. In conclusion, 99Tcm-tetrofosmin may be helpful for detecting tumours of the lungs and adjacent structures, but has limited applicability in differentiating between malignant and benign tumours and may not be used instead of 201Tl to detect malignant tumours of the lungs.

Adenocarcinoma↗
PubMed1998

A viewpoint determination system for stenosis diagnosis and quantification in coronary angiographic image acquisition.

This paper describes the usefulness of computer assistance in the acquisition of "good" images for stenosis diagnosis and quantification in coronary angiography. The system recommends the optimal viewpoints from which stenotic lesions can be observed clearly based on images obtained from initial viewpoints. First, the viewpoint dependency of the apparent severity of a stenotic lesion is experimentally analyzed using software phantoms in order to show the seriousness of the problem. The implementation of the viewpoint determination system is then described. The system provides good user-interactive tools for the semiautomated estimation of the orientation and diameter of stenotic segments and the three-dimensional (3-D) reconstruction of vessel structures. Using these tools, viewpoints that will not give rise to foreshortening and vessel overlap can be efficiently determined. Experiments using real coronary angiograms show the system to be capable of the reliable diagnosis and quantification of stenosis.

Coronary Angiography↗
PubMed1998

Somatic mutations of the PTEN/MMAC1 gene in fifteen Japanese endometrial cancers: evidence for inactivation of both alleles.

Loss of heterozygosity (LOH) of chromosome 10q is observed in approximately 40% of endometrial cancers. Mutations in PTEN/MMAC1, a gene recently isolated from the 10q23 region, are responsible for two dominantly inherited neoplastic syndromes, Cowden disease and Bannayan-Zonana syndrome. Somatic mutations of this gene have also been detected in sporadic cancers of the brain, prostate and breast. To investigate the potential role of this putative tumor suppressor gene in endometrial carcinogenesis as well, we examined 46 primary endometrial cancers for LOH at the 10q23 region, and for mutations in the entire coding region and exon-intron boundaries of the PTEN/MMAC1 gene. LOH was identified in half of the 38 informative cases, and subtle somatic mutations were detected in 15 tumors (33%). Our results suggest that of the genes studied so far in endometrial carcinomas, PTEN/MMAC1 is the most commonly mutated one, and that inactivation of both copies by allelic loss and/or mutation, a pattern that defines genes as "tumor suppressors," contributes to tumorigenesis in endometrial cancers.

Alleles↗
PubMed1998

Frequent allelic loss at 7p14-15 associated with aggressive histologic types of breast cancer.

We examined 142 primary human breast cancers to determine their patterns of loss of heterozygosity (LOH) at 19 microsatellite markers over the entire length of chromosome 7. Allelic loss at one or more loci on the short arm of chromosome 7 was observed in 37 of the tumors (26%). We found a new target region of allelic loss on 7p between D7S1802 and D7S817 at 7p14-15. LOH on 7p was found more frequently in tumors of the invasive solid tubular and scirrhous type (31 of 87); 36%) than in other less aggressive types (2 of 27; 7%) (P = 0.0047). The results suggest that inactivation of putative tumor suppressor gene(s) located at 7p14-15 may play a role in the development and/or progression of primary breast cancers, particularly those of the invasive solid tubular and scirrhous type. Allelic loss was also found in 56 of 142 tumors on the long arm, and a commonly deleted region was defined between D7S522 and D7S1801 at 7q31.

Breast Neoplasms↗
PubMed1998

Incidence of thrombocytopenia in infants born to mothers with idiopathic thrombocytopenic purpura.

Neonatal thrombocytopenia related to maternal idiopathic thrombocytopenic purpura (ITP) is reportedly uncommon but may have severe complications. The present report reviews records of 15 infants born to mothers with ITP during a 10-year period, and the incidence of neonatal thrombocytopenia and the risk of hematological complications is examined. Severe thrombocytopenia (platelets < 50,000/microL) was seen in three infants despite successful therapy with high-dose gamma globulin prior to delivery, which elevated maternal platelet counts. Although the platelet counts of these three infants fell to < 10,000/microL, none had severe complications. Moreover, no infants required treatment such as adrenocorticosteroids, platelets transfusion, or high doses of gamma globulin. No maternal markers predicted the degree of neonatal thrombocytopenia. The risk of complications arising from neonatal thrombocytopenia is low, but careful observation is required for the thrombocytopenic newborn of ITP mothers even when the infant has no bleeding complications at delivery.

Adult↗
PubMed1998

Pharmacological properties of pteleprenine, a quinoline alkaloid extracted from Orixa japonica, on guinea-pig ileum and canine left atrium.

We have investigated the pharmacological properties of pteleprenine, a quinoline alkaloid, on contractile responses of the guinea-pig ileum and on inotropic responses of the canine left atrium. Although pteleprenine (0.1-1 microM) had no effect on the contraction of the ileum induced by acetylcholine at 10 microM it significantly inhibited acetylcholine-induced contraction of the ileum. Pteleprenine (0.1-10 microM) reduced nicotine induced-contraction of the ileum in a concentration-dependent manner yet had no maximum relaxant effect even at a concentration of 10 microM. From Schild analysis the pA2 of pteleprenine on the guinea-pig ileum was found to be 6.6. The contraction of the ileum induced by 10 microM 1,1-dimethyl-4-phenylpiperazinium, a specific agonist of nicotinic acetylcholine receptors, was concentration-dependently suppressed by 10 nM-10 microM pteleprenine. In contrast, 0.1-10 microM pteleprenine did not antagonize the acetylcholine- and nicotine-induced negative inotropic contractile responses of the canine left atrium. These results show that pteleprenine has inhibitory action against nicotinic acetylcholine receptors in the guinea-pig ileum but not in the canine left atrium. Our findings also suggest that pteleprenine might be a novel lead compound as a nicotinic receptor antagonist.

Acetylcholine↗
PubMed1998

Interphase cytogenetic and AgNOR analyses of hydatidiform moles.

AIM: To determine the potential value of interphase cytogenetic and argyrophilic nucleolar organiser region (AgNOR) analyses in the diagnosis and classification of hydatidiform moles. METHODS: Serial tissue sections from 37 hydatidiform moles, histologically classified as 11 complete and 15 partial, and from 11 hydropic abortuses were examined by in situ hybridisation using digoxigenin labelled probes specific for chromosomes 1, X, and Y, and a one step silver staining method. The percentages of diploid and triploid nuclei, and the mean number of AgNORs for each tissue were determined. RESULTS: Interphase cytogenetics showed that eight of the 11 cases (73%) each of complete mole and hydropic abortus had diploid pattern and the three remaining cases (27%) of each group were triploid. Two of the triploid complete moles and one of the triploid hydropic abortuses were revised to partial moles and one remaining triploid complete mole was revised to hydropic abortus. Of the 15 partial moles, nine (60%) were triploid, and six (40%) were diploid. These diploid cases were revised to three complete moles and three hydropic abortuses. There was a significant difference (p < 0.0001) between the mean (SD) AgNOR count in partial mole (5.11 (0.91)) versus hydropic abortus (3.79 (0.90)) and complete mole (3.39 (0.97)). The total of 15 triploid cases showed a high mean AgNOR count of 5.24 (0.73). Also, after reclassification, eight of the nine partial moles (89%) had a mean AgNOR count of > or = 5. The results of analyses by the two methods were closely correlated. CONCLUSIONS: Interphasecytogeneticanalysis using chromosome specific probes and AgNOR count provides a valuable approach for ploidy analysis in histological sections of hydatidiform moles and helps to resolve difficult cases.

Analysis of Variance↗
PubMed1998

Dipyridamole thallium-201 single-photon emission computed tomography for prediction of perioperative cardiac events in patients with arteriosclerosis obliterans undergoing vascular surgery.

The aim of the study was to determine whether or not dipyridamole thallium-201 single-photon emission computed tomography (201Tl-SPECT) has significant additive value for predicting perioperative cardiac events in patients with arteriosclerosis obliterans (ASO) undergoing vascular surgery. Routine preoperative 201Tl-SPECT was performed in 106 consecutive patients with ASO (age 68+/-8.9 years; 91 men and 15 women). The frequency of reversible defects in a clinical high-risk group (n=44) was significantly higher than in a low-risk group (n=62; 55% vs 24%, p<0.01). Perioperative cardiac events occurred in 9 patients, including 4 cardiac deaths, 1 non-fatal myocardial infarction, and 4 cases of unstable angina. Although clinical risk stratification was useful in predicting cardiac events (19% in the high-risk group vs 2% in the low-risk group, p<0.01), the positive predictive value was low. When considering a combination of 2 or more than 2 risk factors and a large reversible defect as a predictor, the positive predictive value and specificity increased from 19% to 47% and from 64% to 91%, respectively, whereas the sensitivity remained unchanged (89%). These results suggest that the addition of 201Tl-SPECT data to clinical risk-stratified patients with ASO allows better prediction of perioperative cardiac events.

Adult↗
PubMed1998

The amino acid sequence of monal pheasant lysozyme and its activity.

The amino acid sequence of monal pheasant lysozyme and its activity were analyzed. Carboxymethylated lysozyme was digested with trypsin and the resulting peptides were sequenced. The established amino acid sequence had one amino acid substitution at position 102 (Arg to Gly) comparing with Indian peafowl lysozyme and four amino acid substitutions at positions 3 (Phe to Tyr), 15 (His to Leu), 41 (Gln to His), and 121 (Gln to His) with chicken lysozyme. Analysis of the time-courses of reaction using N-acetylglucosamine pentamer as a substrate showed a difference of binding free energy change (-0.4 kcal/mol) at subsites A between monal pheasant and Indian peafowl lysozyme. This was assumed to be caused by the amino acid substitution at subsite A with loss of a positive charge at position 102 (Arg102 to Gly).

Amino Acid Sequence↗
PubMed1998

Reptile lysozyme: the complete amino acid sequence of soft-shelled turtle lysozyme and its activity.

Soft-shelled turtle egg-white lysozyme was purified and sequenced. Lysozyme was reduced and carboxymethylated to fragment it with trypsin, V8 protease and CNBr. The peptides yielded were purified by RP-HPLC and sequenced. Every trypsin peptide was overlapped by V8 protease peptides and CNBr fragment. The amino acid sequence was compared with other lysozymes. This lysozyme has an extra Gly residue at N-terminus, which was found in pheasant lysozyme. Further, this lysozyme has an insertion of a Gly residue between 47 and 48 residues when compared with chicken lysozyme, as found in human lysozyme, therefore it proved that this lysozyme has the largest number of amino acids (131 aa) in chicken type lysozymes. The amino acid substitutions were found at subsites E and F. Namely Phe34, Arg45, Thr47, and Arg114 were replaced by His, Tyr, Arg, and Tyr, respectively. The time course using N-acetylglucosamine pentamer as a substrate showed a reduction of the rate constant for glycosidic cleavage and increase of binding free energy for subsites E and F, which proved the contribution of amino acids mentioned above for substrate binding at subsites E and F.

Acetylglucosamine↗
PubMed1998

[The change of localization on cytokeratin of uterine cervix and the relationship to the pattern of invasion in cervical cancer].

An immunohistochemical study of 63 cases of uterine cervical cancer was undertaken. It was confirmed that the biological character of the cancer cells derived from the reserve cells changed over the course of invasion. Squamous cell carcinoma had positive keratin antibodies such as CK 10/13 (DE-K 13), CK 14 (NCL-LL 002) and CK 7 (OV-TL 12/30). In invasive squamous cell carcinoma, CK 14 positive cells were piled up and tended to be stained positive by PCNA and laminin. There were two types of staining, one of which revealed CK 14 strongly positive, and the other weakly positive. The first type differed from the second in depth and localization. The cells on the margin of a cluster of cancer cells were stained positive with CK 14 as in normal basal cells. The results obtained suggested: 1) squamous cell carcinoma has not only the character of normal squamous cells, but also that of the cells derived from the cervical glands. 2) cancer cells may develop in accordance with the character of basal cells, and the patterns of invasion change according to the character of basal cells in cancer tissue.

Biomarkers, Tumor↗