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T Kinoshita

Publications and source records attributed to T Kinoshita.

At least 73 records · Page 4Linked to original sources
PubMed2001

Cross-talk between caveolae and glycosylphosphatidylinositol-rich domains.

Most mammalian cells have in their plasma membrane at least two types of lipid microdomains, non-invaginated lipid rafts and caveolae. Glycosylphosphatidylinositol (GPI)-anchored proteins constitute a class of proteins that are enriched in rafts but not caveolae at steady state. We have analyzed the effects of abolishing GPI biosynthesis on rafts, caveolae, and cholesterol levels. GPI-deficient cells were obtained by screening for resistance to the pore-forming toxin aerolysin, which uses this class of proteins as receptors. Despite the absence of GPI-anchored proteins, mutant cells still contained lipid rafts, indicating that GPI-anchored proteins are not crucial structural elements of these domains. Interestingly, the caveolae-specific membrane proteins, caveolin-1 and 2, were up-regulated in GPI-deficient cells, in contrast to flotillin-1 and GM1, which were expressed at normal levels. Additionally, the number of surface caveolae was increased. This effect was specific since recovery of GPI biosynthesis by gene recomplementation restored caveolin expression and the number of surface caveolae to wild type levels. The inverse correlation between the expression of GPI-anchored proteins and caveolin-1 was confirmed by the observation that overexpression of caveolin-1 in wild type cells led to a decrease in the expression of GPI-anchored proteins. In cells lacking caveolae, the absence of GPI-anchored proteins caused an increase in cholesterol levels, suggesting a possible role of GPI-anchored proteins in cholesterol homeostasis, which in some cells, such as Chinese hamster ovary cells, can be compensated by caveolin up-regulation.

Animals↗
PubMed2001

Decreased functional connectivity of EEG theta-frequency activity in first-episode, neuroleptic-naïve patients with schizophrenia: preliminary results.

We explored and refined the hypothesis that during a first episode of acute schizophrenia a disorganization of brain functioning is present. A novel EEG measure was introduced, Global Field Synchronization (GFS), that estimates functional connectivity of brain processes in different EEG frequency bands. The measure was applied to EEG's from 11 never-treated, first-episode, young patients with an acute, positive, schizophrenic symptomatology and from 19 controls, residing in Bern, Switzerland. In comparison to age- and sex- matched controls, patients had significantly decreased GFS in the theta EEG frequency band, indicating a loosened functional connectivity of processes in this frequency. The result was confirmed in an independent, comparable patient group from Osaka, Japan (9 patients and 9 controls), thus making a total of 20 analyzed patients. Previous EEG research in healthy, awake subjects indicated a positive correlation of theta activity with memory functions. Thus, our result suggests a loss of mutual interdependence of memory functions in patients with acute schizophrenia, which agrees well with previous reports of working memory dysfunction in schizophrenia.

Acute Disease↗
PubMed2001

Crystallization and preliminary X-ray diffraction analysis of NADP-dependent glyceraldehyde-3-phosphate dehydrogenase of Synechococcus PCC 7942.

The NADP-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPDH) of Synechococcus PCC 7942 was crystallized in two different forms by the hanging-drop vapour-diffusion method using ammonium sulfate as a precipitant. Form I crystals were hexagonal, space group P6(5) or P6(1), with unit-cell parameters a = b = 91.1, c = 428.6 A, gamma = 120 degrees. Form II crystals were monoclinic, space group C2, with unit-cell parameters a = 152.3, b = 80.9, c = 213.6 A, beta = 103.1 degrees. Native data were collected from a frozen crystal of form I to a resolution of 2.8 A using synchrotron radiation at SPring-8, whereas form II crystals were easily damaged by radiation at room temperature and increased mosaicity in cryoprotectant solutions. A molecular-replacement solution of the form I crystal was obtained in space group P6(5) using the program AMoRe and the structure of the NAD-dependent GAPDH from Bacillus stearothermophilus.

Crystallization↗
PubMed2001

Efficient retrovirus-mediated PIG-A gene transfer and stable restoration of GPI-anchored protein expression in cells with the PNH phenotype.

Paroxysmal nocturnal hemoglobinuria (PNH) is a clonal hematopoietic stem cell disorder characterized by complement-mediated hemolysis due to deficiencies of glycosylphosphatidylinositol-anchored proteins (GPI-APs) in subpopulations of blood cells. Acquired mutations in the X-linked phosphatidylinositol glycan-class A (PIG-A) gene appear to be the characteristic and pathogenetic cause of PNH. To develop a gene therapy approach for PNH, a retroviral vector construct, termed MPIN, was made containing the PIG-A complementary DNA along with an internal ribosome entry site and the nerve growth factor receptor (NGFR) as a selectable marker. MPIN transduction led to efficient and stable PIG-A and NGFR gene expression in a PIG-A-deficient B-cell line (JY5), a PIG-A-deficient K562 cell line, an Epstein-Barr virus-transformed B-cell line (TK-14(-)) established from a patient with PNH, as well as peripheral blood (PB) mononuclear cells from a patient with PNH. PIG-A expression in these cell lines stably restored GPI-AP expression. MPIN was transduced into bone marrow mononuclear cells from a patient with PNH, and myeloid/erythroid colonies and erythroid cells were derived. These transduced erythroid cells restored surface expression of GPI-APs and resistance to hemolysis. These results indicate that MPIN is capable of efficient and stable functional restoration of GPI-APs in a variety of PIG-A-deficient hematopoietic cell types. Furthermore, MPIN also transduced into PB CD34(+) cells from a normal donor, indicating that MPIN can transduce primitive human progenitors. These findings set the stage for determining whether MPIN can restore PIG-A function in multipotential stem cells, thereby providing a potential new therapeutic option in PNH.

3T3 Cells↗
PubMed2001

An increase in circulating mast cell colony-forming cells in asthma.

We compared a potential to generate mast cells among various sources of CD34(+) peripheral blood (PB) cells in the presence of stem cell factor (SCF) with or without thrombopoietin (TPO), using a serum-deprived liquid culture system. From the time course of relative numbers of tryptase-positive and chymase-positive cells in the cultured cells grown by CD34(+) PB cells of nonasthmatic healthy individuals treated with G-CSF, TPO appears to potentiate the SCF-dependent growth of mast cells without influencing the differentiation into mast cell lineage. CD34(+) PB cells from asthmatic patients in a stable condition generated significantly more mast cells under stimulation with SCF alone or SCF+TPO at 6 wk of culture than did steady-state CD34(+) PB cells of normal controls. Single-cell culture studies showed a substantial difference in the number of SCF-responsive or SCF+TPO-responsive mast cell progenitors in CD34(+) PB cells between the two groups. In the presence of TPO, CD34(+) PB cells from asthmatic children could respond to a suboptimal concentration of SCF to a greater extent, compared with the values obtained by those of normal controls. Six-week cultured mast cells of asthmatic subjects had maturation properties (intracellular histamine content and tryptase/chymase enzymatic activities) similar to those derived from mobilized CD34(+) PB cells of nonasthmatic subjects. An increase in a potential of circulating hemopoietic progenitors to differentiate into mast cell lineage may contribute to the recruitment of mast cells toward sites of asthmatic mucosal inflammation.

Adolescent↗
PubMed2001

Combined laminectomy and thoracoscopic resection of dumbbell-type thoracic cord tumor.

STUDY DESIGN: A study of five patients whose dumbbell or paraspinal tumors of the thoracic spine were managed by using thoracoscopic surgery is reported. OBJECTIVES: To report on the use of combined laminectomy and thoracoscopic resection for the management of dumbbell-type thoracic cord tumor. SUMMARY OF BACKGROUND DATA: Some posterior mediastinal tumors can be resected safely with video-assisted thoracic surgery. However, there are few reports on thoracoscopic resection of dumbbell and paraspinal tumors of the thoracic spine. METHODS: Five patients who received treatment for thoracic spine dumbbell tumors and paraspinal tumors were studied retrospectively. Three patients had dumbbell tumors, and two had paraspinal tumors of the thoracic spine. Preoperative evaluation of each patient included plain chest radiography, magnetic resonance imaging, and computed tomography. All patients underwent total resection by means of a combined posteroanterior approach, with thoracoscopic surgery for dumbbell tumors and thoracoscopic surgery alone for paraspinal tumors. In all patients, a gross total resection was achieved with this approach. All patients were observed for a minimum of 3 years. RESULTS: All patients regained their ability to walk 2 days after surgery, except for one patient who had a hemothorax. A gross total tumor resection, documented by magnetic resonance imaging, was performed on all patients. Follow-up imaging at 6 weeks, 1 year, 2 years, and 3 years after surgery did not show residual tumor or recurrence in any patient. To date, spinal instability has not developed in any patient. CONCLUSIONS: Combined laminectomy and thoracoscopic surgery may be a good alternative method for managing thoracic dumbbell tumors.

Adolescent↗
PubMed2001

Oncostatin M and hepatocyte growth factor induce hepatic maturation via distinct signaling pathways.

Liver development is regulated by soluble factors as well as cell-cell contacts. We previously reported that oncostatin M (OSM) induced hepatic maturation in a primary culture of embryonic day 14 liver cells. While OSM expression in the liver starts in mid gestation and decreases in postnatal stages, hepatocyte growth factor (HGF) is mainly expressed in the liver in the first few days after birth. In this study, we compared the effect of OSM and HGF on the differentiation of fetal hepatic cells in vitro. Like OSM, HGF in the presence of dexamethasone induced expression of glucose-6-phosphatase, tyrosine amino transferase and carbamoyl-phosphate synthase, and accumulation of glycogen in fetal hepatic cells, although to a lesser extent than OSM. Interestingly, while both OSM and HGF up-regulated production of albumin, secretion of albumin occurred only in response to OSM. In addition, although hepatic maturation induced by OSM depends on STAT3, HGF failed to activate STAT3 and HGF-induced differentiation was independent of STAT3. These results indicate that OSM and HGF induce hepatic maturation through different signaling pathways.

Animals↗
PubMed2001

Its8, a fission yeast homolog of Mcd4 and Pig-n, is involved in GPI anchor synthesis and shares an essential function with calcineurin in cytokinesis.

In fission yeast, calcineurin is required for cytokinesis and ion homeostasis; however, most of its physiological roles remain obscure. To identify genes that share an essential function with calcineurin, we screened for mutations that confer sensitivity to the calcineurin inhibitor FK506 and high temperature and isolated the mutant its8-1. its8(+) encodes a homolog of the budding yeast MCD4 and human Pig-n that are involved in glycosylphosphatidylinositol (GPI) anchor synthesis. Consistently, reduced inositol labeling of proteins suggested impaired GPI anchor synthesis in its8-1 mutants. The temperature upshift induced a further decrease in inositol labeling and caused dramatic increases in the frequency of septation in its8-1 mutants. BE49385A, an inhibitor of MCD4 and Pig-n, also increased the septation index of the wild-type cell. Osmotic stabilization suppressed these morphological defects, indicating that cell wall weakness caused by impaired GPI anchor synthesis resulted in abnormal cytokinesis. Furthermore, calcineurin-deleted cells exhibited hypersensitivity to BE49385A, and FK506 exacerbated the cytokinesis defects of the its8-1 mutant. Thus, calcineurin and Its8 may share an essential function in cytokinesis and cell viability through the regulation of cell wall integrity.

Amino Acid Sequence↗
PubMed2001

PIG-M transfers the first mannose to glycosylphosphatidylinositol on the lumenal side of the ER.

Glycosylphosphatidylinositol (GPI) acts as a membrane anchor of many cell surface proteins. Its structure and biosynthetic pathway are generally conserved among eukaryotic organisms, with a number of differences. In particular, mammalian and protozoan mannosyltransferases needed for addition of the first mannose (GPI-MT-I) have different substrate specificities and are targets of species- specific inhibitors of GPI biosynthesis. GPI-MT-I, however, has not been molecularly characterized. Characterization of GPI-MT-I would also help to clarify the topology of GPI biosynthesis. Here, we report a human cell line defective in GPI-MT-I and the gene responsible, PIG-M. PIG-M encodes a new type of mannosyltransferase of 423 amino acids, bearing multiple transmembrane domains. PIG-M has a functionally important DXD motif, a characteristic of many glycosyltransferases, within a domain facing the lumen of the endoplasmic reticulum (ER), indicating that transfer of the first mannose to GPI occurs on the lumenal side of the ER membrane.

Amino Acid Sequence↗
PubMed2001

A novel POZ/zinc finger protein, champignon, interferes with gastrulation movements in Xenopus.

We have cloned a novel krüppel-like transcription factor of Xenopus that encodes POZ/zinc finger protein by expression cloning. Overexpression of mRNA resulted in interference with gastrulation. Because the injected embryo looks like a mushroom in appearance at the neurula stage, we have named this gene champignon (cpg). In cpg-injected embryos, the blastopore appeared normally, but regressed thereafter. The injected embryos then elongated along the primary dorsoventral axis during the tailbud stage. Histologic sections and reverse transcription-polymerase chain reaction analysis showed that cpg had no effect on the cell differentiation. The animal pole region of cpg-injected embryos was thick during the gastrula stage, and mesodermal cells remained in the marginal zone. Furthermore, neither Keller-sandwich explants nor activin-treated animal cap explants excised from cpg-injected embryos elongated. These results suggest that cpg acts as a potent inhibitor of cell migration and cell intercalation during gastrulation.

Animals↗
PubMed2001

Re-treatment of relapsed indolent B-cell lymphoma with rituximab.

The purpose of this study was to investigate the toxicity and the efficacy of re-treatment with rituximab, a chimeric mouse human anti-CD20 monoclonal antibody, in relapsed patients with indolent B-cell non-Hodgkin's lymphoma (NHL) who responded to rituximab in the previous phase I or phase II study. Thirteen patients with relapsed B-cell NHL, each of whom was confirmed to have Revised European-American Lymphoma Classification type II, 1-6 histology (indolent B-NHL), enrolled in this re-treatment study. All were re-treated with rituximab at 375 mg/m2 weekly for 4 consecutive weeks. Rituximab re-treatment was well tolerated with no grade 3/4 nonhematological toxicities, similar to that of the initial treatment. No patients developed detectable human anti-chimeric antibody. Partial responses were observed in 5 of 13 patients (38%; 95% confidence interval [CI], 14% to 68%); 6 patients showed stable disease and 2 showed progressive disease. Overall survival rate was 93% at 19 months of median follow-up after rituximab re-treatment. Median progression-free survival (PFS) after the re-treatment was 5.1 months (95% CI, 4.1 to 5.6 months), and the median PFS after the initial treatment was 8.2 months (95%CI, 5.9 to 11.3 months). Although rituximab re-treatment induced prolonged depletion of normal peripheral blood B cells in all patients, no significant decrease in serum immunoglobulin or complement level was observed. In conclusion, rituximab re-treatment was well tolerated, and it may produce a prolonged PFS in some patients with indolent B-cell NHL who showed initial response to rituximab.

Adult↗
PubMed2001

CD34+-selected autologous peripheral blood stem cell transplantation conditioned with total body irradiation for malignant lymphoma: increased risk of infectious complications.

Although high-dose chemotherapy with autologous peripheral blood stem cell transplantation (autoPBSCT) has been shown or confirmed to be an effective treatment for high-risk and relapsed non-Hodgkin's lymphoma (NHL), relapse after autoPBSCT remains a serious problem. In a clinical trial to overcome relapse, we adopted a treatment plan in which PBSCs purified in vitro to CD34+ cells to deplete tumor cells (CD34+ autoPBSCT), total body irradiation (TBI) of 1200 cGy, and melphalan, 180 mg/m2, were used as a preconditioning regimen. Eighteen patients with relapsed or high-risk NHL participated in the study. This study compared the incidence of complications following CD34+ autoPBSCT preconditioned with the TBI regimen (n = 10): the TBI group; CD34+ autoPBSCT with the non-TBI regimen (n = 8): the non-TBI group; and unselected autoPBSCT with the non-TBI regimen (n = 19): the unselected autoPBSCT control group. After day 30 posttransplantation, 6 of 10 patients treated with the TBI regimen developed 11 infectious complications in total, compared with only 1 of 8 patients treated with the non-TBI regimen and 4 of 19 patients given unselected autoPBSCT. Two fatal complications occurred in the TBI group, but none occurred in the other 2 groups. The CD4+ lymphocyte count at 1 month posttransplantation was significantly lower in the TBI group than in the unselected autoPBSCT group. These findings suggest that the addition of TBI to the preconditioning regimen for CD34+ autoPBSCT is associated with an increased incidence of severe infectious complications after transplantation.

Adult↗
PubMed2001

High-intensity facial nerve lesions on T2-weighted images in chronic persistent facial nerve palsy.

Our aim was to estimate the value of MRI in detecting irreversibly paralysed facial nerves. We examined 95 consecutive patients with a facial nerve palsy (14 with a persistent palsy, and 81 with good recovery), using a 1.0 T unit, with T2-weighted and contrast-enhanced T1-weighted images. The geniculate ganglion and tympanic segment had gave high signal on T2-weighted images in the chronic stage of persistent palsy, but not in acute palsy. The enhancement pattern of the facial nerve in the chronic persistent facial nerve palsy is similar to that in the acute palsy with good recovery. These findings suggest that T2-weighted MRI can be used to show severely damaged facial nerves.

Adolescent↗
PubMed2001

X-Serrate-1 is involved in primary neurogenesis in Xenopus laevis in a complementary manner with X-Delta-1.

Notch, Delta and Serrate encode transmembrane proteins that function in cell fate specification in the Drosophila melanogaster embryo. Here we report gene expression patterns and functional characterization of a Xenopus Serrate homolog, X-Serrate-1. The isolated cDNA encoded a transmembrane protein with a Delta/Serrate/LAG-2 domain, 16 epidermal growth factor-like repeats and a cysteine-rich region. Expression of X-Serrate-1 was observed ubiquitously from unfertilized egg to tadpole, but an upregulation occurred in the tailbud stage embryo. Adult expression was found in eye, brain, kidney, heart, spleen and ovary. Whole-mount in situ hybridization revealed that the organ-related expression in eye, brain, heart and kidney occurred from an early stage of rudiment formation. Overexpression of X-Serrate-1 led to a reduction of primary neurons, whereas an intracellularly deleted form of X-Serrate-1 increased the number of primary neurons. Although the function of X-Serrate-1 in primary neurogenesis was quite similar to that of X-Delta-1, expression of X-Serrate-1 and X-Delta-1 did not affect each other. Co-injection experiments showed that wild-type X-Serrate-1 and X-Delta-1 suppressed overproduction of primary neurons induced by dominant-negative forms of X-Delta-1 and X-Serrate-1, respectively. These results suggest that X-Serrate-1 regulates the patterning of primary neurons in a complementary manner with X-Delta-1-mediated Notch signaling.

Amino Acid Sequence↗
PubMed2001

Invasive carcinoma derived from intraductal papillary-mucinous carcinoma of the pancreas: clinicopathologic and immunohistochemical study of eight cases.

Most intraductal papillary-mucinous carcinomas (IPMCs) of the pancreas are resectable and curable, but some develop into frankly invasive carcinomas. We studied the clinicopathologic features of eight cases of invasive carcinoma derived from IPMC (IC-IPMC) of the pancreas. The patients were aged 54-75 years (mean, 66.6 years); six were male and two were female. The mean tumor size was 7.7 cm (range 5.5-10.5 cm). Two patients without lymph node metastasis had no peripancreatic invasion, and survived longer (115 and 20 months). Three out of four patients with extrapancreatic invasion died of their tumors or developed tumor recurrence within a year. One patient with evidence of liver and lymph node metastasis at the time of first surgery again showed metastatic tumor 21 months later. One patient died of another cause. We also performed a comparative study of the immunohistochemical features of IC-IPMCs in 9 IPMCs (including minimally invasive cases) and 15 ductal adenocarcinomas. CEA cytoplasmic positivity was observed in most of the IC-IPMCs (87.5%) and ductal adenocarcinomas (93.3%), but in only 1 IPMC (11.1%). The frequency of p53 nuclear staining in ductal adenocarcinoma (73.3%) was higher than in IPMC (33.3%) or IC-IPMC (37.5%). In conclusion, IC-IPMC with extrapancreatic invasion should be treated as ductal carcinoma because of its aggressive behavior after resection. Some IPMCs might progress to invasive carcinoma via pathways that are different from those followed by ductal adenocarcinomas.

Adenocarcinoma, Mucinous↗