Biomedical subjects

S Takeuchi

Publications and source records attributed to S Takeuchi.

At least 109 records · Page 6Linked to original sources

PubMed1997

Presenilin 1 binds to amyloid precursor protein directly.

Mutations in the presenilin genes are associated with early onset familial Alzheimer's disease and lead to accumulation of beta-amyloid peptide in the brain of patients, suggesting that presenilin abnormalities induce pathological processing of amyloid precursor protein (APP) in Alzheimer's disease. For the understanding of pathogenesis in this type of familal Alzheimer disease, it is important to know whether presenilins are directly involved in the metabolism of beta-amyloid or not. To test whether presenilin 1 (PS1) directly binds to APP, we performed two-hybrid interaction assays between these proteins in yeast cells by using bait plasmids for normal and mutant PS1 and prey plasmids for APP fragments corresponding to the different molecular portions. Positive interaction was observed in any combination between PS1 bait plasmids and APP prey plasmids. Therefore, our results show that PS1 binds to APP directly and suggest that the PS1 protein itself is involved in the metabolism of beta-amyloid peptide.

Alzheimer Disease↗

PubMed1997

Frequent loss of heterozygosity in the region of the D7S523 locus in advanced ovarian cancer.

Loss of heterozygosity (LOH) of the long arm of chromosome 7 occurs frequently in many types of primary cancers. We analyzed 22 primary ovarian cancers for LOH of chromosome arm 7q using a set of 16 microsatellite markers in order to determine the location of a putative tumor suppressor gene (TSG). Eleven samples (50%) showed LOH at least at one locus on chromosome arm 7q. We identified the smallest commonly deleted region to be at 7q31.1, which includes D7S523. LOH of chromosome arm 7q was more frequent in advanced stages (III-IV) (7/9, 78%) than in early stages (I-II) (4/13.31%) of ovarian cancer (P < 0.05). These data suggest that alteration of a TSG at 7q31.1 gene plays an important role in advanced ovarian cancer.

Chromosome Deletion↗

PubMed1997

Treatment of empyema by transposition of contralateral lower trapezius flap.

We report the successful treatment of bronchopleural fistula and empyema using transposition of a contralateral lower trapezius musclocutaneous flap, which provided immediate obliteration of the middle-back empyema cavity. This technique is easy to perform without any intraoperative change of position and with little postoperative impairment of the back and shoulder movement.

Bronchial Fistula↗

PubMed1997

Anastomosis of the superficial temporal artery to the middle cerebral artery with the interposed occipital artery graft in moyamoya disease: case report.

BACKGROUND: Although there have been various interposed bypass grafts used for cerebral revascularization, the occipital artery has never been used as a graft. Interposed occipital artery bypass graft in an adult case with moyamoya disease after failed indirect revascularization is presented. CASE DESCRIPTION: This 34-year-old woman with moyamoya disease, who had suffered from cerebral ischemic symptoms since the age of 6 years, was admitted to our hospital because of an intracerebral hemorrhage on the left side. She had undergone superficial temporal-to-middle cerebral artery anastomosis, encephalo-galeo-synangiosis on the right side, and encephalo-duro-arterio-synangiosis on the left side at age 29 years. Four months after the intracerebral hemorrhage, she still had cerebral ischemic symptoms in the left hemisphere where cerebral revascularization was poor. Since neither the superficial temporal nor occipital artery could be used for direct anastomosis because of spontaneous transdural anastomoses of the superficial temporal artery and the short length of the occipital artery, anastomosis between the left superficial temporal artery and left posterior parietal artery was performed using a left occipital artery graft 6 months after the hemorrhage. Postoperative external carotid angiograms showed good patency of the graft. CONCLUSION: In cases in which direct anastomosis is infeasible for cerebral revascularization, the occipital artery could successfully be used as a bypass graft.

Adult↗

PubMed1997

Intra-aneurysmal pressure changes during angiography in coil embolization.

BACKGROUND: Although elevation of blood pressure in aneurysms induced by injection of contrast medium has been postulated as a major cause of rerupture of ruptured cerebral aneurysms during angiography, no study has proved the elevation of intra-aneurysmal pressure because of difficulty in measuring the intra-aneurysmal pressure during angiography. The present study demonstrated intra-aneurysmal pressure to be raised by injection of contrast medium, using a microcatheter introduced into aneurysms. METHODS: To confirm the accuracy of pressure measurement through a microcatheter, we measured intra-aneurysmal pressure in a plastic model of an artery and an aneurysm during and after injection of contrast medium through a microcatheter and a needle inserted into the aneurysm. In a clinical study, intra-aneurysmal pressures were measured through the microcatheter in nine cerebral aneurysms of seven patients. RESULTS: In the model experiment, changes in the pressure measured through the microcatheter correlated well with those observed through the needle. In the clinical study, intra-aneurysmal systolic pressures increased by 5-23 mm Hg immediately after injection of contrast medium for 1-3 s in four basilar tip, three internal carotid-ophthalmic, and one middle cerebral artery aneurysm, whereas no pressure change was observed in a posterior cerebral artery aneurysm. Systemic blood pressure during angiography remained unchanged in all cases. CONCLUSIONS: This abruptly elevated intra-aneurysmal pressure by injection of contrast medium might cause rerupture of an aneurysm soon after rupture of the aneurysm, especially when the rupture site is fragile.

Adult↗

PubMed1997

C/EBP-epsilon: chromosomal mapping and mutational analysis of the gene in leukemia and preleukemia.

We and others have cloned a novel human gene CCAAT/enhancer-binding protein epsilon (C/EBP-epsilon) encoding a member of the C/EBP gene family. It is exclusively expressed in myeloid and T-lymphoid cells and appears to have an important role in inducing expression of several myeloid-specific genes. We used a polymerase chain reaction (PCR)-based technique to examine DNA from 93 hamster/human radiation hybrid clones in order chromosomally to map C/EBP-epsilon to 14q11.2 (between D14S264 and D14S275) which is telomeric to the T-cell receptor alpha and delta genes and centromeric to several other myeloid gene products including Cathepsin G (CTSG) and Chymase-1 (CMA1). To determine whether C/EBP-epsilon behaves as an altered tumor-suppressor gene, samples from patients with acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) evolving to AML were studied for loss of heterozygosity (LOH) using microsatellite sequences that we identified within 0.2 kb of the amino-terminus of the human C/EBP-epsilon gene. Allelic loss of the C/EBP-epsilon gene was detected in four out of 20 (20%) evolving MDS cases and in none of the 17 AML and 17 T-cell leukemia cases. Mutational analysis of the gene was performed using PCR-SSCP on 37 AML and 40 MDS cases including those with LOH at the gene. No abnormalities were found suggesting that the altered gene in this region is not C/EBP-epsilon. Also, C/EBP-epsilon was examined by Southern blot analysis on DNA samples from 20 AML patients and 10 AML cell lines. No rearrangements or amplifications of the gene were detected. Taken together, we have mapped C/EBP-epsilon to 14q11.2, a region containing other myeloid and T-lymphoid specific genes. Furthermore, no structural alterations were detected in the C/EBP-epsilon gene.

Acute Disease↗

PubMed1997

Role of tyrosine specific phosphorylation of cellular proteins, especially EGF receptor and p125FAK in human lung cancer cells.

To clarify the role of tyrosine phosphorylation of cellular proteins in human lung cancer cells, phosphotyrosine (PTYR)-containing proteins in lung cancer cell lines and in paired tissues resected from cancerous and normal lungs were studied by immunoblotting with an anti-PTYR antibody. We found that the profiles of protein phosphorylation were very similar among those cell lines which had different histological features. The major PTYR-containing proteins (180-190 KDa, 120-130 KD, and 95-100 KDa) were detected in lung cancer cell lines. The expression of EGF receptor (EGF-r) (p185) and o-erb B2 protein, and tyrosine phosphorylation of p125FAK were examined in cancerous lung tissues and normal lung tissues. In surgical specimens, approximately half of the samples of lung cancer tissues showed clear elevation of tyrosine phosphorylation. In these cancerous tissues, no clear amplification of EGF-r and c-erb B2 protein expression was observed. However, elevation of tyrosine phosphorylation of p125FAK was observed in cancerous lung tissues but not in normal lung tissues, and its phosphorylation was closely correlated with the nodal involvement of cancer and disease-free survival time. These results suggested that the intracellular signaling pathway via tyrosine phosphorylation plays a role in the generation and immortalization of lung cancer, and assessment of tyrosine phosphorylation of cellular proteins. especially p125FAK, may be available clinically as a prognostic factor.

Adult↗

PubMed1997

Changes in the volume of marginal cells induced by isotonic 'Cl- depletion/restoration': involvement of the Cl- channel and Na+-K+-Cl- cotransporter.

Marginal cells constitute the endolymph-facing epithelium responsible for the secretion of endolymph by the stria vascularis in the inner ear. We have studied the possible involvement of Cl- conductance and Na+-K+-Cl- cotransport in the mechanism of changes in cell volume upon isotonic Cl- depletion/restoration. Changes in cell volume were estimated from video-microscopic images with the aid of an image processor. Marginal cells shrank to approximately 80% of their original volume in 30 s and to 65-70% in 90 s upon total replacement of [Cl]o (approximately 150 mM) by gluconate-, and the original volume of the shrunken cells was restored within 2 min after restoration of Cl-. The order of potency of anions to induce isotonic shrinkage was gluconate > I- > F- > Br-. The cell shrinkage caused by Cl- depletion was partially inhibited by 5-Nitro-2-(3-phenyl-propylamino)-benzoic acid (NPPB, 0.2 mM), but not by either 4-acetamido-4'-isothiocyanato-stilbene-2,2'-disulfonic acid (SITS, 0.5 mM), bumetanide (10 microM) or ouabain (1 mM). The cell shrinkage caused by a reduction of [Cl]o from approximately 150 mM to 7.5 mM was not affected by [K]o in the range of 3.6 mM to 72 mM. These results suggest that the main efflux pathway(s) responsible for the 'Cl removal'-induced shrinkage depends on volume-correlated Cl- conductance (Takeuchi and Irimajiri, J. Membrane Biol. 150, 47-62, 1996) and that this pathway(s) is essentially independent of the Na+-K+-Cl- cotransporter, the Na+,K+-ATPase, and the K+-Cl- cotransporter. With regard to volume recovery after isotonic shrinkage, its critical dependence on the simultaneous presence of Na+, K+ and Cl- in the bath and its substantial inhibition by bumetanide (10 microM) both indicate a major role for Na+-K+-Cl- cotransport. The strong influence on cell volume of solute fluxes working through the Cl- channel and the Na+-K+-Cl- cotransporter implies an essential role for these pathways in the ion transport mechanism(s) of the marginal cell.

Animals↗

PubMed1997

Marginal cells of the stria vascularis of gerbils take up glucose via the facilitated transporter GLUT: application of autofluorescence.

Strial marginal cells are known to take up and metabolize glucose as their main source of metabolic energy. The membrane transport mechanisms for glucose uptake into strial marginal cells, however, are largely unknown. Two types of glucose transporters in mammalian cells have been described, the facilitated glucose transporter GLUT and the sodium/glucose cotransporter SGLT. The goal of the present study was to determine which of these represent the main glucose uptake mechanism in strial marginal cells. Glucose uptake into strial marginal cells was assessed by monitoring the cellular concentration of the reduced form of nicotinamide adenine dinucleotide (NADH) fluorometrically. The relation between the autofluorescence from marginal cells and cellular metabolism was verified as follows. The autofluorescence (excitation: 340 nm, emission: 450-490 nm) decreased when oxidative phosphorylation in the mitochondria was uncoupled with carbonyl cyanide 3-chlorophenylhydrazone (CCCP) and increased when cytochrome oxidase was inhibited with cyanide. These effects indicate that the autofluorescence is dependent on the mitochondrial metabolic state, and more specifically on the level of NADH in mitochondria. Glucose removal from the bath solution elicited a 39% decrease in the autofluorescence intensity within 5 min. Similarly, cytochalasin B (10 microM) reduced the fluorescence intensity by 34% in 5 min. In contrast, neither phlorizin (0.1 mM) nor Na+ removal from the bath solution caused any appreciable change in the autofluorescence intensity. These results indicate that glucose depletion affects the metabolic state of the marginal cell within a few minutes, and that marginal cells take up glucose via GLUT, but not via SGLT. Since the excitation and emission wavelengths of several fluorescent dyes used in physiological studies (e.g., Fura-2 and SBFI) are similar to those of NADH, possible effects of autofluorescence on recording signals should always be taken into account when these dyes are utilized.

Animals↗

PubMed1997

Long-term follow-up of surgical patients with single-ventricle physiology: prognostic anatomical determinants.

Although univentricular or biventricular repair is not always possible for hearts with single-ventricle physiology, it has been proven to produce a satisfactory outcome. It is hypothesized that patient prognosis can be predicted by anatomical diagnosis at presentation. Between 1961 and 1995, 158 patients with single-ventricle physiology, including tricuspid atresia and hypoplastic left heart syndrome, were referred to the authors' institute, and underwent 260 surgical interventions. Follow-up was 99% complete. Patient survival and anatomical risk factors were examined by the Kaplan-Meier method, and multivariate analysis including the Cox proportional hazard model. Mean (s.e.m.) actuarial survival rates at 1, 5, 10 and 20 years following birth were 70.3(3.6)%, 56.3(4.0)%, 48.8(4.2)%, and 40.9(4.7)%, respectively. Definitive palliation was attempted in 38 patients (univentricular in 35 and biventricular in three). Multivariate analysis identified systemic ventricular outflow tract obstruction, mitral atresia, situs ambiguus, and pulmonary vein drainage tract obstruction as independent prognostic factors for overall survival. Visceral heterotaxy was the only independent risk factor for lack of application or failure (death or take-down within 30 days of operation) of univentricular or biventricular repair. In conclusions, these anatomical factors in hearts with single-ventricle physiology affect long-term mortality, despite multiple and heterogeneous surgical efforts.

Female↗

PubMed1997

Severe lactic acidosis and neonatal death in Pearson syndrome.

Pearson marrow-pancreas syndrome, a fatal disease associated with mitochondrial DNA rearrangements, is characterized by refractory sideroblastic anaemia during infancy. Only a few neonates with Pearson syndrome have been reported with metabolic acidosis. A female neonate who exhibited severe metabolic acidosis and anaemia at birth is described here. Her condition progressively worsened, with pancytopenia and uncontrollable metabolic acidosis resulting in death at the age of 14 days. A 4988-base pair deletion of mtDNA was detected in the patient's leukocytes, liver and muscle. When a neonate exhibits severe metabolic acidosis of unknown cause, the possibility of Pearson syndrome should be considered.

Acidosis, Lactic↗

PubMed1997

Ovarian cancer has frequent loss of heterozygosity at chromosome 12p12.3-13.1 (region of TEL and Kip1 loci) and chromosome 12q23-ter: evidence for two new tumour-suppressor genes.

Identification of the key genetic alterations leading to ovarian cancer is in its infancy. Polymerase chain reaction (PCR)-based analysis of loss of heterozygosity (LOH) is a powerful method for detecting regions of altered tumour-suppressor genes. Focusing on chromosome 12, we examined 23 ovarian cancer samples for LOH using 31 highly polymorphic microsatellite markers and found the chromosomal localization of two putative tumour-suppressor genes. Two commonly deleted regions were 12p12.3-13.1 in 6/23 (26%) and 12q23-ter in 7/23 (30%) samples. LOH on chromosome 12 was more common in late-stage ovarian carcinomas. The region of LOH at 12p12.3-13.1 includes the genes that code for the ETS-family transcriptional factor, known as TEL, and the cyclin-dependent kinase inhibitor, known as p27Kip1. Mutational analysis of both TEL and p27Kip1 using single-strand conformation polymorphism (SSCP) showed no abnormalities, suggesting that the altered gene in this region is neither of these genes. Taken together, our data suggest that new tumour-suppressor genes in the region of chromosomes 12p12.3-13.1 and 12q23-ter may be involved in the development of ovarian cancer.

Adenocarcinoma↗

PubMed1997

Absence of microsatellite instability during the progression of chronic myelocytic leukemia.

Microsatellites are highly polymorphic, short-tandem repeat sequences dispersed throughout the genome. To test the occurrence of genetic instability in the progression of chronic myelocytic leukemia (CML), we studied microsatellite instability (MSI) in 17 patients with CML. The DNAs from both chronic phase and blast crisis were analyzed at 10 loci. No MSI was observed in any of the 17 cases of blast crisis. These results indicate that MSI is rare and is not associated with progression to blast crisis in most cases of CML.

Blast Crisis↗

PubMed1997

TEL is one of the targets for deletion on 12p in many cases of childhood B-lineage acute lymphoblastic leukemia.

Abnormalities of the short arm of chromosome 12 including loss of heterozygosity (LOH) and TEL/AML-1 fusion resulting from a t(12;21)(p13;q22) translocation are frequently observed in childhood acute lymphoblastic leukemia (ALL). We investigated 21 DNA samples of childhood ALL which had LOH at 12p13. Rearrangement of TEL was observed in eight cases and another case showed a homozygous deletion of TEL. Two informative samples with TEL rearrangement had a deletion localized to the 5' region of this gene. The deletion in these two cases includes the helix-loop-helix (HLH) domain. This is consistent with the hypothesis that the normal tel can heterodimerize with the TEL/AML-1 gene product and inhibit the transforming capacity of the chimeric protein. Presumably, loss of the HLH of the normal remaining TEL allele abrogates this tumor suppressor-like function. The case with homozygous deletion of TEL is also consistent with this gene having qualities of a tumor suppressor. One unusual case had T-ALL rather than B-lineage ALL and the leukemic cells had rearrangement of TEL, but they did not have an alteration of the remaining TEL allele suggesting that the etiology of this disease may be different. This analysis further emphasizes the importance of loss of the normal TEL allele in childhood precursor B-lineage ALL.

Blotting, Southern↗

PubMed1997

Homozygous deletions at 9p21 in childhood acute lymphoblastic leukemia detected by microsatellite analysis.

To gain a fuller understanding of the role of deletions of chromosome 9 in the development of childhood acute lymphoblastic leukemia (ALL), we performed detailed deletional mapping of chromosome 9 in 54 primary ALL samples with matched normal DNA using 22 highly polymorphic markers; and this information was combined with our previous data concerning the presence of deletions of CDKN2/INK4A/p16 and CDKN2B/INK4B/p15 in these samples. We have found a very high frequency of loss of heterozygosity (LOH) (31 of 54 cases (57%)) on chromosome arm 9p. As expected, the smallest region of LOH was between D9S1747 and D9S1748 at 9p21, including CDKN2/INK4A/p16, but excluding CDKN2B/INK4B/p15. Homozygous deletions at 9p21 occurred in 23 of 54 (43%) samples (seven of 11 (64%) T-ALL, 16 of 45 (36%) precursor-B ALL). We detected seven cases of homozygous deletions at 9p21 which had not been detected by Southern blot hybridization, showing the power of microsatellite analysis in detecting homozygous deletions. In most cases, homozygous deletions were limited to the region between D9S1747 and CDKN2B/INK4B/p15. We have attempted to determine the mechanism and timing of 9p deletions. Of the 23 samples with homozygous deletions at 9p21, 21 samples had surrounding large LOH. Of the 29 samples with LOH of 9p, homozygous deletion at 9p21 was identified in 22 cases. In addition, six patients have been studied at diagnosis and relapse, all six showed the same 9p21 structure at relapse (normal, three patients; hemizygous deletions, two patients; homozygous deletion, one patient) as their initial presentation. Finally, three patients (homozygous deletion, one patient; hemizygous deletion, two patients) had the IFN-alpha rather than CDKN2/INK4A/p16 deleted. In summary, these data further emphasize the importance of 9p21 loss in the development of childhood ALL.

Carrier Proteins↗

PubMed1997

Microsatellite instability and other molecular abnormalities in childhood acute lymphoblastic leukaemia.

Microsatellite instability (MSI) has been considered to represent the defect of DNA mismatch repair systems and has been implicated in the tumourigenesis of several human malignancies. To investigate the possible presence of microsatellite instability in childhood acute lymphoblastic leukaemia (ALL), we examined 48 primary ALL samples. Instability was determined at 85 different microsatellite loci localized to 12 different chromosome arms. Microsatellite instability was detected in five (10%) samples. Interestingly, the instability was found at chromosomal regions associated with frequent alterations. Two samples had instability at the microsatellite marker within the TEL gene on chromosome arm 12p. Two other samples had instability at a microsatellite marker close to CDKN2/p16 on 9p; one of these samples had a homozygous deletion at 9p21. The fifth sample had instability at the microsatellite marker on 6q, which we have found is a frequent region of loss of heterozygosity in childhood ALL. Taken together, instability was rare in childhood ALL, but was localized to the three most frequently deleted chromosome regions in childhood ALL, suggesting that localized microsatellite instability may identify a fragile chromosomal region which could result in alteration of surrounding target genes and lead to leukaemia.

Blotting, Southern↗

PubMed1997

Microsatellite instability during the progression of acute myelocytic leukaemia.

We studied microsatellite instability (MSI) at the onset and during progression of 17 individuals with acute myelocytic leukaemia (AML). These included two cases of MO, eight with M1 and seven with M4, according to the FAB classification. The DNA from diagnostic, remission and relapsed stages of their disease was analysed at 69 loci. Two MSI were found in the diagnostic and remission phase paired samples (12%), and eight MSI were identified in six of the relapsed phase samples (35%). These results indicate that mismatch repair errors such as MSI are unimportant at the onset of AML, but might have importance during the progression of the disease.

Acute Disease↗

PubMed1997

Adrenergic neurotransmitters and calcium ionophore-induced situs inversus viscerum in Xenopus laevis embryos.

Xenopus laevis embryos at the blastula-early tail bud stage were exposed to norepinephrine or octopamine dissolved in culture saline until they reached the larval stage. The left-right asymmetry of the heart and gut was then examined. We found that these adrenergic neurotransmitters induced situs inversus in the heart and/or gut in up to 35% of tested neurula embryos. Norepinephrine-induced situs inversus was blocked by the alpha-1 adrenergic antagonist prazosin. Furthermore, A23187, a calcium ionophore, also increased the incidence of situs inversus up to 54% when late-neurula embryos were exposed to the solution. A23187 treatment initiated before neural groove formation was less effective. The incidence of situs inversus induced by these reagents decreased towards the control level (2.2%, 25 untreated embryos out of 1127 embryos in total) in embryos past the stage of neural tube closure. In the present experiments we obtained 22 gut-only situs inversus embryos having an inverted gut and a normal heart. In contrast, such embryos were not observed among the 1127 untreated embryos. An adrenergic signal mediated by an increase in intracellular free calcium may be involved in the asymmetrical visceral morphogenesis of Xenopus embryos.

Adrenergic alpha-Agonists↗