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Biomedical subjects

T Ito

Publications and source records attributed to T Ito.

At least 397 records · Page 22Linked to original sources
PubMed2000

Developmental changes of CD34 expression by murine hematopoietic stem cells.

It has been reported that fetal murine hematopoietic stem cells are CD34(+), whereas adult stem cells are CD34(-). We sought to delineate the developmental changes of CD34 expression by hematopoietic stem cells and carried out systematic analysis of long-term engrafting cells in the bone marrow and/or blood of perinatal, juvenile, and adult mice. To obtain information on the total population of stem cells, we prepared CD34(+) and CD34(-) populations of mononuclear cells without prior enrichment and assayed their long-term reconstituting abilities by transplantation into lethally irradiated Ly-5 congenic mice. All stem cells from perinatal to 5-week-old mice were CD34(+). In 7-week-old mice, CD34(-) stem cells began to emerge, and the majority of the stem cells were CD34(-) in the 10- and 20-week-old mice. Approximately 20% of adult stem cells expressed CD34. Developmental changes of CD34 expression from the positive to the negative state takes place between 7 and 10 weeks of age for the majority of murine stem cells. Approximately 20% of adult stem cells remain CD34(+). These observations provide insight into the current controversy regarding CD34 expression by adult hematopoietic stem cells and suggest that the majority of stem cells in human umbilical cord blood and bone marrow of young children are CD34(+).

Aging↗
PubMed2000

Overexpression of Ets-1 transcription factor in angiosarcoma of the skin.

Angiosarcoma of the skin is a rare malignant tumor which is slow-growing but highly aggressive and often recurs following surgery and/or radiation therapy, finally metastasizing to the regional lymph nodes. The ets-1 protooncogene is shown to be transcribed in endothelial cells during angiogenesis in granulation tissue and in malignant cells during tumor invasion. Furthermore, it can regulate the expression of metalloproteinase genes such as collagenase-1 (MMP-1), stromelysin (MMP-3) and urokinase-type plasminogen activator (uPA). In this study we investigated the ets-1 and MMP-1 expression in 7 angiosarcomas of the skin, compared with 7 hemangiomas and 7 granuloma pyogenicums of the skin, which are well known as benign vascular diseases. The ets-1 and MMP-1 mRNAs and their proteins were overexpressed in all angiosarcomas tested, and the localization of MMP-1 expression corresponded to that of ets-1. On the other hand, they were weakly or not at all expressed in hemangiomas and granuloma pyogenicums. These results suggest that the constitutive overexpression of ets-1 might be closely related with the malignant progression of angiosarcoma, possibly through the up-regulation of the transcription of MMP-1.

Adult↗
PubMed2000

Detection of pulmonary metastasis of low-grade endometrial stromal sarcoma 25 years after hysterectomy.

Endometrial stromal sarcoma (ESS) is a rare uterine sarcoma. Low-grade ESS occasionally recurs or metastasizes after long disease-free periods, a fact that may complicate the diagnosis. Here we report a case of multiple lung metastases in a 68-year-old woman who had been disease-free for 25 years after hysterectomy for a uterine tumor. Biopsy revealed that the tumor was composed of oval cells with slight nuclear atypism but without mitotic figures, suggesting a low-grade neoplasm. Immunostaining for intermediate filaments revealed strong positivity for vimentin and weak positivity for alpha-smooth muscle actin. In addition, immunostaining for estrogen and progesterone receptors, performed under suspicion of low-grade ESS, was positive. The uterine tumor resected many years before had shown a similar morphology. Thus, it was demonstrated that the lung neoplasm was a metastatic low-grade ESS that had appeared after many disease-free years. A review of the literature revealed that this case had the longest recorded interval between the occurrence of the initial ESS and the development of distant metastases. When low-grade sarcoma appears in the lungs of female patients, it is important to consider the possibility of low-grade ESS. Detailed information on the past clinical history, together with immunostaining for estrogen and progesterone receptors, are important diagnostic keys.

Disease-Free Survival↗
PubMed2000

Repetitive intermittent hypoxia-ischemia and brain damage in neonatal rats.

OBJECTIVE: To know the effect of brief-repetitive intermittent hypoxia-ischemia on the development of perinatal brain damage. STUDY DESIGN: Seven-day-old Wistar rats underwent ligation of the unilateral common carotid artery. The animals were allocated to three groups (n=12 in each group) and exposed to 8% oxygen as follows: group A: continuous exposure for 180 min; group B: continuous exposure for 90 min; and group C: 10 min of exposure repeated at 10-min intervals over a period of 180 min (total exposure time, 90 min). Seventy-two hours after exposure to hypoxia, the cerebral cortex was examined to assess the degree of neuronal necrosis and brain damage was classified into four grades of severity, 0-3. To evaluate the extent of brain damage, we used immunohistochemical staining with TIB-128 antibody, which reacts to MAC-1 antigen specific to microglia, and observed the glial reaction in the cerebral cortex, hippocampus, thalamus, and striatum. RESULTS: All the brain damage observed in groups A-C occurred on the side where the ligation was performed. The most severe damage was found in group A animals, of which seven showed significant neuronal necrosis, having a grade 2 or more advanced lesion. In group B, neuronal necrosis was modest, with only one animal having a grade 2 lesion. In group C, a significant neuronal necrosis was found in six animals despite having the same period of hypoxic exposure as those in group B. MAC-1 positive cells appeared in the cerebral cortex of histologically damaged animals and extended to the hippocampus, thalamus, and striatum in severely damaged animals from groups A, B, and C. CONCLUSION: Examination of the neonatal rat model suggested that repetitive and intermittent, rather than continuous hypoxia-ischemia, causes pronounced damage in the immature brain.

Animals↗
PubMed2000

Divergence of glyceraldehyde-3-phosphate dehydrogenase isozymes in Saccharomyces cerevisiae complex.

Although sake yeasts are placed in Saccharomyces cerevisiae, we have been interested in their difference from the other subgroups of the species, and examined their proteins. When SDS-PAGE patterns of their soluble proteins were compared, specific differences between subgroups were found in their 36,000 Da regions. Proteins isolated therefrom were found to be subunits of three isomers of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from their N-terminal amino acid sequences and identified with anti-GAPDH serum. Therefore, comparison of zymogram was carried out by a modified method: denatured monomers were observed and the enzyme activity of their oligomers was not considered. SDS-PAGE patterns of all the sake yeasts differed from those of the other strains of S. cerevisiae. Strains of Saccharomyces bayanus showed uniform patterns which are different from the above two groups. Saccharomyces pastorianus strains resembled S. bayanus and were partly similar to S. cerevisiae in their patterns, in agreement with the hypothesis that S. pastorianus is a hybrid between these two species. Patterns of S. paradoxus appeared to be rather similar to those of sake yeasts. Results on the other species of the genus and on the preliminary experiments on PAGE of native isozymes are also described.

Alcoholic Beverages↗
PubMed2000

Angiographic no-reflow phenomenon as a predictor of adverse long-term outcome in patients treated with percutaneous transluminal coronary angioplasty for first acute myocardial infarction.

OBJECTIVES: We sought to elucidate the long-term prognostic importance of angiographic no-reflow phenomenon after percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction (AMI). BACKGROUND: Angiographic no-reflow phenomenon, a reduced coronary antegrade flow (Thrombolysis in Myocardial Infarction [TIMI] flow grade < or =2) without mechanical obstruction after recanalization, predicts poor left ventricular (LV) functional recovery and survival in the early phase of AMI. We hypothesized that angiographic no-reflow phenomenon also predicts long-term clinical outcome. METHODS: We studied 120 consecutive patients with their first AMI treated by PTCA without flow-restricting lesions. The patients were classified as either no-reflow (n = 30) or reflow (TIMI-3) (n = 90) based on post-PTCA cineangiograms to follow up (5.8 +/- 1.2 years) for cardiac death and nonfatal events. RESULTS: Patients with no-reflow had congestive heart failure (p < 0.0001), malignant arrhythmia (p = 0.038), and cardiac death (p = 0.002) more often than did those with reflow. Kaplan-Meier curves showed lower cardiac survival and cardiac event-free survival (p < 0.0001) in patients with no-reflow than in those with reflow. Multivariate analyses disclosed that no-reflow phenomenon was an independent predictor of long-term cardiac death (relative risk [RR] 5.25, 95% confidence interval [CI] 1.85 to 14.9, p = 0.002) and cardiac events (RR 3.71, 95% CI 1.79 to 7.69, p = 0.0004). At follow-up, survivors with no-reflow had higher end-diastolic and end-systolic LV volume indices and plasma brain natriuretic peptide levels, and lower LV ejection fractions (p = 0.0002, p < 0.0001, p = 0.002, p < 0.0001, respectively) than did those with reflow, indicating that no-reflow may be involved in LV remodeling. CONCLUSIONS: Angiographic no-reflow phenomenon strongly predicts long-term cardiac complications after AMI; these complications are possibly associated with LV remodeling.

Adult↗
PubMed2000

Compressive optic nerve atrophy resulting from a distorted internal carotid artery.

An 18-month-old female with right compressive optic nerve atrophy caused by an ipsilateral distorted internal carotid artery is reported. She was referred to an ophthalmologist at 8 months of age with the complaint of unilateral visual loss. Neuroimaging studies should contribute markedly to the determination of the causes of visual problems in young children.

Carotid Artery, Internal↗
PubMed2000

Repulsive axon guidance molecule Sema3A inhibits branching morphogenesis of fetal mouse lung.

Semaphorin III/collapsin-1 (Sema3A) guides a specific subset of neuronal growth cones as a repulsive molecule. In this study, we have investigated a possible role of non-neuronal Sema3A in lung morphogenesis. Expression of mRNAs of Sema3A and neuropilin-1 (NP-1), a Sema3A receptor, was detected in fetal and adult lungs. Sema3A-immunoreactive cells were found in airway and alveolar epithelial cells of the fetal and adult lungs. Immunoreactivity for NP-1 was seen in fetal and adult alveolar epithelial cells as well as endothelial cells. Immunoreactivity of collapsin response mediator protein CRMP (CRMP-2), an intracellular protein mediating Sema3A signaling, was localized in alveolar epithelial cells, nerve tissue and airway neuroendocrine cells. The expression of CRMP-2 increased during the fetal, neonate and adult periods, and this pattern paralleled that of NP-1. In a two-day culture of lung explants from fetal mouse lung (E11.5), with exogenous Sema3A at a dose comparable to that which induces growth cone collapse of dorsal root ganglia neurons, the number of terminal buds was reduced in a dose-dependent manner when compared with control or untreated lung explants. This decrease was not accompanied with any alteration of the bromodeoxyuridine-positive DNA-synthesizing fraction. A soluble NP-1 lacking the transmembrane and intracellular region, neutralized the inhibitory effect of Sema3A. The fetal lung explants from neuropilin-1 homozygous null mice grew normally in vitro regardless of Sema3A treatment. These results provide evidence that Sema3A inhibits branching morphogenesis in lung bud organ cultures via NP-1 as a receptor or a component of a possible multimeric Sema3A receptor complex.

Animals↗
PubMed2000

Peroxynitrite formation by diesel exhaust particles in alveolar cells: Links to pulmonary inflammation.

Diesel exhaust particles (DEP) are assumed to be a causal substance for pulmonary inflammation. As peroxynitrite is recently implicated in inflammation and cytotoxity, the hypothesis was tested that instillation of DEP induces formation of peroxynitrite in cells migrated in lung. Rats were intratracheally instilled with DEP suspension (2 mg/0.5 ml/kg) and killed 24 h later. Alveolar cells were collected by broncho-alveolar lavage. Population of alveolar cells increased more than twice by DEP exposure, mainly due to a large increase of neutrophils. Peroxynitrite formation (N(G)-nitro-L-arginine methylester and superoxide dismutase inhibitable chemiluminescence) was detected in alveolar cells from treated rats, and 12-O-tetradecanoylphorbol 13-acetate-stimulation enhanced it. In addition, DEP induced expression of inducible NO synthase mRNA in these cells. But peroxynitrite was not detectable in cells from control. These results indicate that DEP exposure results in peroxynitrite formation in migrated cells, which leads to pulmonary inflammation.

Journal Article↗
PubMed2000

Clinical and morphologic features of perimembranous ventricular septal defect with overriding of the aorta--the so-called Eisenmenger ventricular septal defect. A study making comparisons with tetralogy of Fallot and perimembranous ventricular defect without aortic overriding.

The aim of our study was to elucidate the clinical and morphologic features of those perimembranous ventricular septal defects which extend between the ventricular outlets, particularly when found in association with anterior deviation of the muscular outlet septum and overriding of the aorta--the so called Eisenmenger ventricular septal defect. From 1990 through 1998, we have undertaken surgical correction in 203 patients with perimembranous ventricular septal defect. Of these, 15 patients had the Eisenmenger ventricular septal defect. We conducted retrospective analyses of the clinical records, catheterization data, and angiocardiographic and echocardiographic finding of these patients. Comparative studies were then made with the patients having tetralogy of Fallot, and those with simple perimembranous ventricular septal defects without overriding of the aorta. In the patients with the Eisenmenger ventricular septal defect, the extent of anterior deviation of the outlet septum was comparable with that seen in tetralogy of Fallot, but there was less rightward displacement of the aortic valvar orifice. In contrast to earlier investigators, however, we found evidence of progressive narrowing of the subpulmonary infundibulum in those with the Eisenmenger defect. These morphological features were reflected in the clinical features, since all patients showed evidence of increased pulmonary flow and congestive heart failure in early infancy, but with two-thirds of them subsequently developing right-to-left shunting. We conclude, therefore, that the Eisenmenger ventricular septal defect is a discrete cardiac abnormality in which the morphologic substrate of anterior deviation of the outlet septum gives rise to a potential for progressive narrowing of the subpulmonary infundibulum. Surgical management, therefore, needs to take account of such narrowing as an additional cardinal morphologic feature.

Angiocardiography↗
PubMed2000

Ubiquinone systems in fungi. V. Distribution and taxonomic implications of ubiquinones in Eurotiales, Onygenales and the related plectomycete genera, except for Aspergillus, Paecilomyces, Penicillium, and their related teleomorphs.

The ubiquinone (coenzyme Q) systems were determined for 176 teleomorphic isolates, 14 anamorphic isolates, and three samples of fruit-bodies of Dendrosphaera eberhardtii, which belonged to Eurotiales, Onygenales, and related taxa. In Eurotiales, Ascosphaera had Q-9, whereas Bettsia had Q-10. All isolates of Monascaceae had the Q-10 system, whereas those of four genera of Pseudeurotiaceae had the Q-10(H2) system. The Q-10(H2) system was found in genera of Trichocomaceae, except for Aspergillus, Penicillium, Paecilomyces, and their related taxa. However, Thermoascus had the Q-9 system. In Onygenales, members of Arthrodermataceae had Q-9, and those of Gymnoascaceae had Q-10(H2). Isolates of Myxotrichaceae were characterized by Q-10(H2) with few exceptions, which had Q-10. The quinones of Onygenaceae belonged to complex systems, i.e., Q-9, 0-10 and 0-10(H2), and a combination of two systems. Families Onygenaceae and Trichocomaceae are likely a phylogenetic heterogeneity. Ubiquinone analysis provides a very useful criterion of great promise for classifying eurotialean taxa and also for identifying their isolates.

Ascomycota↗
PubMed2000

Flower-predominant expression of a gene encoding a novel class I chitinase in rice (Oryza sativa L.).

A flower-predominant cDNA for a gene, termed OsChia 1;175, was isolated from a cDNA library of rice pistils. Northern blot and RT-PCR analyses revealed that the OsChia 1;175 gene is highly expressed in floral organs (pistils, stamens and lodicules at the heading stage) but not or at an extremely low level in vegetative organs. OsChia 1;175 encodes a protein that consists of 340 amino acid residues, and the putative mature protein shows 52% to 63% amino acid identity to class I chitinases of rice or other plants. The phylogenetic tree shows that the OsChia 1;175 protein is a new type of plant class I chitinase in rice. The expression of OsChia 1;175 in vegetative organs is not induced by several chemicals, UV, and wounding. The soluble putative mature OsChia 1;175 protein expressed in Escherichia coli exhibited chitinase activity in the assay with colloidal chitin as a substrate. Genomic Southern analysis revealed that the OsChia 1;175 gene was organized as a low-copy gene family. The rice genomic library was screened and a genome clone corresponding to OsChia 1;175 was isolated. The transcription start sites of the OsChia 1;175 gene were mapped by primer extension analysis. The 1.2 kb putative promoter region of the OsChia 1;175 gene was fused to the GUS (beta-glucuronidase) gene, and this chimeric gene was introduced to rice by Agrobacterium-mediated transformation. The flower-predominant gene expression was identified also in the transgenic rice plants. The high promoter activity was detected in the stigmas, styles, stamens and lodicules in transgenic plants. The possible functions of OsChia 1;175 are discussed.

Amino Acid Sequence↗
PubMed2000

Transepithelial transport of levofloxacin in the isolated perfused rat kidney.

PURPOSE: The transepithelial transport of levofloxacin was evaluated in the isolated perfused kidney to investigate its renal secretory mechanisms. METHODS: Levofloxacin was instantaneously administered into the renal artery together with inulin and Evans blue-labeled albumin, and the single-pass dilution curves of the renal venous and urinary outflow were determined in the absence or presence of various compounds. Kinetic parameters were computed based on non-compartment moment analysis. RESULTS: The ratio of fractional excretion to filtration fraction (FE/FF) for levofloxacin was 2.99 +/- 0.18, indicating the involvement of tubular secretion. In the presence of cimetidine and quinolones, the FE/FF of levofloxacin was significantly decreased and the transepithelial mean transit time (Tcell) of levofloxacin was prolonged. The Tcell showed a negative correlation with renal secretion of levofloxacin, while the volume of distribution of levofloxacin showed no correlation. CONCLUSIONS: Transport on the brush-border membrane plays a determining step in the renal secretion of levofloxacin, and cimetidine and quinolones interact with levofloxacin transport on the brush-border membrane.

Animals↗
PubMed2000

Generation of HLA-A2 subtype specific cytotoxic T lymphocytes from cord blood used for cord blood stem cell transplantation.

Alloantigen reactive cytotoxic T lymphocytes (CTL) were generated from cord blood (CB) lymphocytes used for cord blood stem cell transplantation (CBSCT). The CTL were cytotoxic against the patient's leukemic cells, as well as the patient's EBV-lymphoblastoid cell line (EBV-LCL), and PHA blasts. The cytotoxicity against patient's EBV-LCL was blocked by anti-HLA-A2 MoAb, and anti-HLA-class I MoAb. The CTL recognized A*0206 positive EBV-LCLs, but not A*0201, A*0204, or A*0207 positive EBV-LCLs, suggesting that this CTL recognizes HLA-A*0206. This case suggests that CB T cells may be competent enough to generate CTL to induce a GVL effect, together with those against A*0206, in patients with CBSCT.

Antigens, Neoplasm↗
PubMed2000

A novel strategy for cancer therapy by mutated mammalian degenerin gene transfer.

Mammalian degenerin (MDEG) is a member of the amiloride-sensitive sodium ion channel family, and its site-directed active mutant (MDEG-G430F) induces massive Na+ influx into cells, leading to cell ballooning and cell bursting. We attempted a novel therapeutic approach for gastric cancers by transferring MDEG-G430F into cancer cells using tumor-specific promoters. In carcinoembryonic antigen (CEA)-producing gastric cancer cells, the level of cell death observed when MDEG-G430F was used with a CEA promoter was similar to that observed when using a potent nonspecific promoter such as the cytomegalovirus promoter. In an in vivo study, fusogenic liposome complexes containing MDEG-G430F driven by the CEA promoter were injected intraperitoneally into CEA-producing gastric cancer cells in a mouse peritoneal dissemination model. Although all 15 of the control mice were dead by 50 days postinoculation, 13 of the 15 mice treated with MDEG-G430F survived. These results indicate that transferring MDEG-G430F into cancer tissues using tumor-specific promoters can achieve striking and selective cancer cell death irrespective of the transcriptional efficiency of the promoters used in vivo, and suggest that this approach is a promising new strategy for cancer gene therapy.

Acid Sensing Ion Channels↗