Biomedical subjects

T Tsuji

Publications and source records attributed to T Tsuji.

At least 19 recordsLinked to original sources

PubMed1995

Identification of two isoforms of mouse neuropeptide Y-Y1 receptor generated by alternative splicing. Isolation, genomic structure, and functional expression of the receptors.

Two cDNA clones homologous with human neuropeptide (NP) Y-Y1 receptor have been isolated from a mouse bone marrow cDNA library. One was thought to be the cognate of the human NPY-Y1 receptor, termed Y1 alpha receptor, and the other form, termed Y1 beta receptor, differed from the Y1 alpha receptor in the seventh transmembrane domain and C-terminal tail. Analysis of the mouse genomic DNA showed that both receptors originated from a single gene. The different peptide sequences of the Y1 beta receptor were encoded by separate exons, hence, these receptors were generated by differential RNA splicing. High affinity binding of [125I]NPY to each receptor expressed in Chinese hamster ovary (CHO) cells and sequestration of [125I]NPY after binding to each receptor were observed. In the CHO cells expressing the Y1 alpha receptor, intracellular Ca2+ increase, inhibition of forskolin-induced cAMP accumulation, and mitogen-activated protein kinase (MAPK) activation were observed by stimulation of NPY, and these responses were abolished by pretreatment with pertussis toxin. Since wortmannin completely inhibited NPY-elicited MAPK activation, we speculate that wortmannin-sensitive signaling molecule(s) such as phosphoinositide 3-kinase may lie between pertussis toxin-sensitive G-protein and MAPK. In contrast, these intracellular signals were not detected in CHO cells expressing the Y1 beta receptor. Northern blots and reverse transcriptase-polymerase chain reaction analyses indicated that the Y1 alpha receptor was highly expressed in the brain, heart, kidney, spleen, skeletal muscle, and lung, whereas the Y1 beta receptor mRNA was not detected in these tissues. However, the Y1 beta receptor was expressed in mouse embryonic developmental stage (7 and 11 days), bone marrow cells and several hematopoietic cell lines. These results suggest that the Y1 beta receptor is an embryonic and a bone marrow form of the NPY-Y1 receptor, which decreases in the expression during development and differentiation.

Alternative Splicing↗

PubMed1995

Activation induces dephosphorylation of cofilin and its translocation to plasma membranes in neutrophil-like differentiated HL-60 cells.

We suggested that a cytosolic 21-kDa phosphoprotein played an important role in opsonized zymosan-trigered activation of superoxide-generating enzyme in neutrophil-like HL-60 cells through dephosphorylation (Suzuki, K., Yamaguchi, T., Oshizawa, T., Yamamoto, Y., Nishimaki-Mogami, T., Hayakawa, T., and Takahashi, A (1995) Biochim. Biophys. Acta 1266, 261-267). In the present study, we characterized the phosphoprotein and studied changes in it localization upon activation of phagocytes. The 21-kDa phosphoprotein was rapidly dephosphorylated upon activation not only wit opsonized zymosan but also with formyl-Met-Leu-Phe and arachidonic acid. The peptide fragments derived from the 21-kDa phosphoprotein were found to have the same amino acid sequences as those of cofilin, an actin-binding protein. The phosphoprotein reacted exclusively with anti-cofilin antibody on two dimensional immunoblots. Accordingly, together with its apparent molecular weight, isoelectric point, and detection of phosphoserine as a phosphoamino acid, we concluded that the 21-kDa phosphoprotein was a phosphorylated form of cofilin. The amount of cofilin in membranous fractions was increased upon activation. Furthermore, confocal laser scanning microscopy showed that cofilin existed diffusely in the cytosol and nuclear region of the resting cells, while in the activated cells, it was accumulated at the plasma membrane area, forming ruffles or endocytic vesicles on which O2.- should be produced. These results suggested that in resting cells cofilin exists as a soluble phosphoprotein in the cytosol and nuclei, while upon stimulation a large portion of cofilin is dephosphorylated and translocated to the plasma membrane regions.

Actin Depolymerizing Factors↗

PubMed1995

Q-wave regression unrelated to patency of infarct-related artery or left ventricular ejection fraction or volume after anterior wall acute myocardial infarction treated with or without reperfusion therapy.

We examined the relation of Q-wave regression to left ventricular (LV) indexes in acute anterior wall myocardial infarction (AMI) in relation to reperfusion therapy. A total of 94 patients with their first anterior wall AMI (segment 6 or 7 occlusion according to the American Heart Association classification) were examined. The follow-up period with 12-lead electrocardiograms ranged from 6 to 60 months (mean 24 +/- 18). An abnormal Q wave was defined as > 40 ms and > 25% of the R-wave amplitude. Q-wave regression was defined as Q-wave disappearance and r-wave regression > 0.1 mV in > or = 1 lead. Contingency tables with the chi-square test and analysis of variance were used for assessment of the relation between Q-wave regression and angiographic and clinical indexes. Q-wave regression in > or = 1 lead was found in 77% of the patients. The incidence of Q-wave regression in patients with patent infarct-related artery (81%) was not significantly different from that in those with an occluded lesion (67%). Q-wave regression appeared within 1 month in 60% of patients with a patent infarct-related artery but in 25% of those with an occluded lesion. No difference in the incidence of Q-wave regression was seen between patients with lesions at segments 6 (81%) and 7 (70%), or between those with (75%) and without (77%) collateral circulation. Q-wave regression did not correlate with LV ejection fraction, LV end-diastolic or end-systolic volumes, or regional wall motion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

cDNA cloning of mouse VLA-3 alpha subunit.

cDNA clones for mouse VLA (very late antigen)-3 alpha subunit (alpha 3 integrin) were isolated and sequenced. The encoded mouse alpha 3 integrin subunit was composed of 1,053 amino acid residues. The results of sequence analysis revealed similar structural characteristics of other VLA alpha subunits. For example, the presence of a large extracellular domain including three putative metal binding sequences, a transmembrane domain, and a short cytoplasmic domain. A higher level of its message was detected in thymus than in kidney, stomach, spleen, liver, brain, or lung by Northern blotting analysis.

3T3 Cells↗

PubMed1995

Characterization of human colon carcinoma variant cells selected for sialyl Lex carbohydrate antigen: liver colonization and adhesion to vascular endothelial cells.

The content of sialyl Lewis-X antigen (Neu5Ac alpha 2-3Gal beta 1-4(fuc alpha 1-3)GlcNAc-R: sialyl Le(x)) was previously shown to correlate with the progression of human colon carcinomas to the advanced stages. Variant cell lines with high (KM12-HX) or low (KM12-LX) levels of cell surface sialyl Le(x) were isolated from the heterogeneous KM12C cells to characterize the biological behavior of colon carcinoma cells with elevated cell surface contents of sialyl Le(x). When these cells were injected intrasplenically into nude mice, KM12-HX cells colonized to the liver more efficiently than KM12-LX cells. Under in vitro conditions, KM12-HX cells demonstrated greater degree of adhesion to cytokine-activated human umbilical vein endothelial cells than KM12-LX cells. The adhesion of KM12-HX cells was partially inhibited by antibodies specific for E-selectin, which was known to serve as a ligand for the sialyl Le(x) carbohydrate antigen. The treatment of KM12-HX cells with benzyl N-acetyl-alpha-D-galactosaminide, a putative inhibitor of the extension of O-linked carbohydrate chains, reduced the rate of adhesion. These results suggested that the interaction of endothelial cell surface E-selectin with O-linked carbohydrate chains on colon carcinoma cell surface glycoproteins played an important role in the adhesion.

Animals↗

PubMed1995

Human hand impedance characteristics during maintained posture.

The present paper examines human hand impedance characteristics, including inertia and viscosity as well as stiffness, in multi-joint arm movements. While a subject maintains a given hand location, small external disturbances are applied to his hand by a manipulandum. The corresponding force-displacement vectors are measured and sampled over time in order to estimate the hand impedance by means of a second-order linear model. The experimental results in different subjects and hand locations are summarized as follows: (1) the estimated inertia matrices of the human hand well agrees with computed values using a two-joint arm model, (2) spatial variations of the stiffness ellipses are consistent with the experimental results of Mussa-Ivaldi et al. (1985), (3) hand stiffness and viscosity increase with the grip force of the subject, and (4) viscosity and stiffness ellipses tend to have similar orientation. The accuracy of the impedance estimation method is validated with a mechanical spring-mass system with known parameters.

Adult↗

PubMed1995

Brain tissue identification based on myosin heavy chain isoforms.

Non-muscle tissues contain 3 myosin heavy chain (MHC) isoforms; MIIA, MIIB1 and MIIB2. MIIA is a non-muscle type isoform distributed in all non-muscle tissues and smooth-muscle, while MIIB1 and MIIB2 are brain-type isoforms distributed mainly in neuronal tissues. The ratio of MIIA and MIIB (A/B ratio) differs between tissues, suggesting that this ratio may be a useful marker for tissue identification. To apply the A/B ratio for tissue identification in forensic practice, we developed a highly sensitive ELISA for quantification of each MHC isoform. At least 100 pg of both MHC isoforms could be detected by the present method. Analysis of the A/B ratio of the cerebrum, cerebellum, liver, kidney, spleen and andrenal gland by the present method indicated that the A/B ratio of the brain tissue (< 0.5) was quite different from other tissues (> 3.0). The A/B ratio could be determined from at least 8 micrograms of fresh tissue sample and 0.1 mg of dried tissue sample stored for 1 month at room temperature. Therefore, the A/B ratio seems to be an excellent marker for identification of the brain tissue.

Adrenal Glands↗

PubMed1995

Analysis of asparagine-linked oligosaccharides by sequential lectin affinity chromatography.

Lectins are proteins that specifically bind to a particular carbohydrate structure. Affinity chromatography with immobilized lectins is a quite effective technique not only for the fractionation of glycoproteins or oligosaccharides but also their structural assessment. In this article, we focus on the separation of glycopeptides and oligosaccharides derived from glycoproteins by affinity chromatography on immobilized lectin columns.

Agglutinins↗

PubMed1995

Histologic modification by cryopreservation in rat aortic allografts.

Histologic changes after the cryopreserved rat aortic transplantation were studied, and the influences of the cryopreservation and of the allografting on the histology were examined. Four groups of Brown Norway (RT1n) and Lewis rats (RT1(1)) were used (n = 4 at each examined period in each group): the cryopreservation-allograft group (from Brown Norway to Lewis with cryopreservation), the cryopreservation-isograft group (from Lewis to Lewis with cryopreservation), the fresh allograft group (from Brown Norway to Lewis without cryopreservation), and the fresh isograft group (from Lewis to Lewis without cryopreservation). The graft was harvested from a descending thoracic aorta of a donor rat, implanted to an infrarenal abdominal aorta of a recipient rat, and extracted at 10 days, 1, 3, 6, and 12 months after the operation. The intimal thickening, cellular loss in the media, and cellular infiltration in the adventitia were observed, which were the same phenomena seen in chronic rejection of human organ allografts. Although the degree of intimal thickening and cellular loss in the media were higher in the cryopreserved groups than in the fresh groups, the cryopreservation procedure suppressed cellular infiltration in the adventitia after allotransplantation. The immunologic attack against the graft might be diminished by cryopreservation.

Animals↗

PubMed1995

Detection of decay-accelerating factor in stool specimens of patients with colorectal cancer.

BACKGROUND & AIMS: Colorectal cancers have an increased expression of decay-accelerating factor (DAF). The aim of this study was to determine whether stool specimens of patients with colorectal cancer contain increased amounts of DAF. METHODS: DAF was measured using an immunoassay in the stool specimens of 40 persons with colorectal cancer, 18 with colorectal adenomatous polyps, 13 with upper gastrointestinal cancer, and 41 without gastrointestinal disease. RESULTS: Stool DAF concentrations in patients with colorectal cancer (0-9.8 ng/g stool; median, 1.6 ng/g) were significantly higher than those in patients with adenoma (0-6.4 ng/g; median, 0 ng/g) (P < 0.05), patients with upper gastrointestinal cancer (0-3.1 ng/g; median, 0 ng/g) (P < 0.05), and subjects without gastrointestinal disease (0-3.4 ng/g; median, 0 ng/g) (P < 0.01). Resection of colorectal cancers caused a marked decrease in stool DAF concentrations. The stool DAF test was positive in a substantial portion of patients with colorectal cancer whose tumors were small ( < 2 cm), at an early TNM stage, or unassociated with fecal occult blood positivity. The sensitivity of the test for colorectal cancer was 55%, and the specificity was 85%. CONCLUSIONS: The measurement of stood DAF deserves evaluation as a test for detection of colorectal cancer.

Adenomatous Polyposis Coli↗

PubMed1995

Flow cytometric analysis of the DNA content in colorectal adenomas with focal cancers.

BACKGROUND & AIMS: Variable results have been reported on the nuclear DNA content of colorectal polyps. The significance of DNA aneuploidy in the malignant transformation of colorectal polyps was evaluated. METHODS: We analyzed by flow cytometry the nuclear DNA content of freshly frozen samples of 50 colorectal adenomas with or without focal cancers, analyzing separately the adenomatous and cancerous regions of the polyps. RESULTS: In the adenomatous regions of the 50 polyps, the DNA was diploid in 43 and aneuploid in 7; the adenomas with DNA aneuploidy in the adenomatous regions were more frequently accompanied by focal cancers than were the DNA-diploid adenomas (P < 0.01). In 60% of the polyps with DNA aneuploidy in the cancerous regions, the DNA was also aneuploid in the adenomatous region and had similar DNA indices; this result suggests that the DNA aneuploidy had already occurred during the adenomatous stage, which lends support to the concept of the adenoma-carcinoma sequence. DNA aneuploidy in the adenomatous region was significantly correlated with the size of colorectal polyps (P < 0.05). CONCLUSIONS: DNA aneuploidy may be an important indicator for the early diagnosis of malignant transformation of colorectal polyps.

Adenoma↗

PubMed1995

Virion-like structures in HeLa G cells transfected with the full-length sequence of the hepatitis C virus genome.

BACKGROUND & AIMS: The process and the site of hepatitis C virus (HCV) particle formation in cells after infection remain unknown. The aim of this study was to create an in vitro model for the study of HCV particle formation. METHODS: HeLa G cells were transfected with the full-length sequence of the HCV genome. Viral protein expression was analyzed using immunoblotting. The cells were examined using immunoelectron and conventional electron microscopy. RESULTS: Core, E2, NS3, NS5a, and NS5b proteins were identified using immunoblotting. Immunoelectron microscopy showed that the core antigen was located along the membrane of the endoplasmic reticulum (ER) and occasionally in its cisternae. Core antigen-positive particles of 30 nm in diameter were found in the cytosol and in the cisternae of the ER. The particles in the cisternae were coated with an outer membrane that was connected to the ER membrane. Conventional electron microscopy revealed particles of 45 nm in diameter with electron-dense cores in the cisternae of the ER. The outer membrane of the particles was occasionally connected to the ER membrane. CONCLUSIONS: The findings suggest that HCV core proteins are synthesized and assembled into particles in the cytosol and that they bud into the cisternae of the ER to form coated particles.

Base Sequence↗

PubMed1995

Dysembryoplastic neuroepithelial tumor: report of three cases.

BACKGROUND: Dysembryoplastic neuroepithelial tumor (DNT) is one of the mixed neuronal-glial tumors that should be differentiated from low-grade gliomas. The recognition and correct diagnosis of DNT is important because this tumor is curable by excision. METHODS: We report three cases of histologically proven DNTs with various image studies performed preoperatively and describe characteristic findings of them, as well as those of previous reports. RESULTS: In our three cases, computed tomography (CT) showed a well-defined, nonenhancing hypodense area. Magnetic resonance imaging (MRI) demonstrated a cortical mass of hypointensity on T1- and of marked hyperintensity on T2-weighted images. I-123-IMP or Tc-99m-HMPAO single-photon emission computed tomography (SPECT) images showed marked hypoperfusion of the lesion. Thallium-SPECT showed no uptake. CONCLUSIONS: I-123-IMP, Tc-99m-HMPAO, and Thallium-SPECT images, as well as CT and MRI, may be helpful in distinguishing DNT from low-grade gliomas.

Adult↗

PubMed1995

Short-term increase in prostaglandin I2 synthesis caused by cicletanine in patients with essential hypertension.

Cicletanine is a new antihypertensive drug that stimulates renal and vascular synthesis of prostaglandin (PG) I2 in experimental animals. However, there is little evidence that cicletanine increases the level of PGI2 in systemic blood of human subjects. To investigate the short-term antihypertensive mechanism of cicletanine, we measured serially the systemic blood pressure, the levels of 6-keto-PGF1 alpha (a stable metabolite of PGI2) and PGE2, and renin activity in plasma after administration of the drug. Nine patients with essential hypertension on a diet without severe sodium restriction took 100 mg of the drug by mouth. Systemic blood pressure was measured hourly for 24 h before and after cicletanine administration. The two PGs of interest were extracted, purified by high pressure liquid chromatography, and measured by radioimmunoassay. Cicletanine decreased blood pressure 3 and 6 h after administration and increased the plasma level of 6-keto-PGF1 alpha. The increase in 6-keto-PGF1 alpha was small but significant (mean +/- SD, from 3.21 +/- 1.26 to 3.88 +/- 1.44 and later 4.15 +/- 1.08 pg/mL by 3 and 6 h after administration; P < .05 and .01, respectively). The level of PGE2 had increased at 3 h after administration but returned to baseline by 6 h. Plasma renin activity was increased only at 24 h after administration. Cicletanine increased systemic PGI2 levels short-term, producing an antihypertensive effect in patients with essential hypertension.

6-Ketoprostaglandin F1 alpha↗

PubMed1995

The significance of PCNA and p53 protein in some oral tumors.

The expression of PCNA and p53 protein was evaluated in a total of 75 cases of benign and malignant lesions of the oral cavity, comprising 50 squamous cell carcinomas (SCCs), 14 leukoplakias, and 11 pleomorphic adenomas. The DNA histogram of 20 SCCs was measured by flow cytometry. p53-positive cells were frequently seen in SCCs, but were rare in leukoplakias and pleomorphic adenomas. The PCNA labeling index (LI) was higher in SCCs than in other benign lesions. The expression rate of p53 protein was markedly elevated in SCCs obtained from smoking patients, when compared to nonsmoking patients. DNA ploidy did not show a close relationship with PCNA and p53 expression. The mean value of PCNA LI for 22 cases carrying positive p53 protein was 52.3%, which was higher than that of p53 protein negative cases (35.7%). The Kaplan-Meier survival curve of the patients who were negative for p53 was significantly more favorable than for patients who were positive for p53 (P < 0.01, Cox-Mantel test). These results suggest that PCNA and p53 LI are markers for the malignant potential of the oral mucosa, and are a useful indicator suggesting a poor prognosis.

Actuarial Analysis↗

PubMed1995

Vasoconstrictor mechanism of neuropeptides augmented after endothelial removal in isolated, perfused canine basilar arteries.

In order to investigate the functional role of endothelium and vasoeffector mechanism in cerebrovascular responses to neuropeptides, the stainless steel cannula inserting method was applied to examine the responses to intraluminally-applied bradykinin, substance P and vasopressin in isolated and perfused canine basilar arteries. In control vessels with intact endothelium, each neuropeptide induced a monophasic dilation at lower doses, and a biphasic response, i.e., an initial dilation followed by a secondary constriction, at higher doses. The dilation was significantly reduced and the constriction was significantly enhanced, while the dilation to papaverine was not modified by endothelial removal with intraluminal saponin. The same tendency was observed in the responses after extraluminal treatment with oxyhaemoglobin. The monophasic constrictions to prostaglandin F2 alpha and potassium chloride were significantly potentiated by the endothelial removal. The augmented constrictions to the neuropeptides were significantly diminished by indomethacin (a cyclooxygenase inhibitor), OKY-046 (a thromboxane synthetase inhibitor) and nimodipine (a dihydropyridine calcium antagonist), but not by AA-861 (a lipoxygenase inhibitor). These results suggest that the neuropeptide causes an endothelium-dependent dilation and a constriction of smooth muscles, and that the enhanced constriction might be relevant in part with thromboxane A2, linked with calcium influx into smooth muscle cells in cerebral arteries.

Animals↗

PubMed1995

Transient expression of a brain/embryonic-type myosin heavy chain isoform (MIIB2) in regenerating rat liver.

The expressions of non-muscle-type (MIIA) and brain/embryonic-type (MIIB2) myosin heavy-chain isoforms in regenerating rat liver were examined. In regenerating liver after partial hepatectomy, the level of MIIA was nearly constant, while that of MIIB2 increased transiently. The level of MIIB2 was very low in normal livers, and increased gradually and then declined with a peak at the 4th day, when the regeneration was almost completed. The level of proliferating cell nuclear antigen was highest at the 2nd day. Serine dehydratase activity in the liver decreased on partial hepatectomy, began to increase at the 5th day, and reached 71% of the control at the 7th day. These results suggest that MIIB2 plays a role in reconstruction or differentiation of the regenerating tissues rather than in proliferation of hepatocytes.

Animals↗

PubMed1995

Deleted in oral cancer-1 (doc-1), a novel oral tumor suppressor gene.

We have identified, isolated, and partially characterized doc-1, a novel cDNA sequence whose activity is consistent with a suppressor of hamster oral carcinogenesis. Doc-1 is an evolutionarily conserved gene exhibiting loss of heterozygosity and marked reduction in expression in malignant hamster oral keratinocytes. The full-length doc-1 cDNA encodes an 87 amino acid product that shows a significant homology to one of the seven novel genes induced in mouse fibroblasts by TNF-alpha. Transfection of the full-length doc-1 cDNA into malignant hamster oral keratinocytes alters the behavior of the recipients in terms of morphology, growth rate, and anchorage-independent growth, suggesting reversion of transformation phenotypes. We propose that doc-1 is a novel tumor suppressor gene in oral cancer development.

Amino Acid Sequence↗