Biomedical subjects

T Sudo

Publications and source records attributed to T Sudo.

At least 73 records · Page 4Linked to original sources

PubMed1998

Flt3/Flk-2 and c-Kit are not essential for the proliferation of B lymphoid progenitor cells in the bone marrow of the adult mouse.

The receptor tyrosine kinase Flk-2/Flt3 was originally cloned from hematopoietic stem cell-enriched fetal liver and placenta and is believed by some investigators to play a role in the regulation of the hematopoietic stem cell. However, targeted disruption of the flt3 gene results in a specific deficiency in early B cell progenitors. Using an antagonistic monoclonal antibody developed against the extracellular domain of Flt3, we investigated the expression and function of the molecule on B lymphoid lineage cells in the bone marrow (BM) of adult mice. Approximately 10% of B220+ cells in the BM expressed Flt3 on the cell surface, and most of the cells belonged to a pro-B cell fraction when judged by an expression pattern of CD43, heat-stable antigen, and BP-1. However, B lymphoid precursor cells that are clonable in vitro could not be enriched in the B220+/Flt3+ cell fraction sorted by flow cytometry. Furthermore, proliferation of B lymphoid precursor cells in the adult BM was not blocked by administration of the antagonistic monoclonal antibodies against Flt3 and c-Kit, suggesting that signalings mediated by Flt3 and c-Kit receptors are not essential for the proliferation of B cell progenitors in adult mouse BM.

Animals↗

PubMed1998

[Annexin family].

Explore the source record for details and available documents.

Amino Acid Sequence↗

PubMed1997

Osteoclast precursors in bone marrow and peritoneal cavity.

Osteoclasts differentiate from cells that share some phenotypes with mature macrophages and monocytes, but early precursors for osteoclasts still remain obscure. To characterize osteoclast precursors, using monoclonal anti-c-Fms and anti-c-Kit antibodies, bone marrow cells were separated and the frequency of clonogenic progenitors were measured. Osteoclast precursors in the bone marrow mainly expressed c-Kit and diminished in frequency when they expressed c-Fms. In contrast to bone marrow, the precursors in the peritoneal cavity were enriched with a population of c-Fms+. Injection of these antibodies into mice demonstrated that peritoneal osteoclast precursors were sensitive to anti-c-Fms but not to anti-c-Kit antibodies, whereas those in bone marrow only declined in the presence of both antibodies. Meanwhile, c-Fms as opposed to c-Kit played an essential role in the generation of osteoclasts in cultures. We also compared osteoclast precursors with colony forming cells (CFU-M) by a macrophage colony stimulating factor. CFU-M in bone marrow decreased when anti-c-Kit antibody was administered and no CFU-M was detected in peritoneum. In this study, we show differences between proliferative potential osteoclast precursors maintained in bone marrow and peritoneum and between CFU-M and osteoclast precursors.

Animals↗

PubMed1997

Expression of MAGE genes in osteosarcoma.

Expression of MAGE genes that encode tumor-rejection antigens recognized by cytotoxic T lymphocytes with major histocompatibility complex class-I antigens was investigated in human osteosarcomas (20 cell lines and eight fresh tumor tissues). MAGE-1, 2, 3, 4, and 6 genes were expressed at the mRNA level in 11 (52.4%), 10 (47.6%), 10 (47.6%) one (4.8%), and 10 (47.6%) of 21 tumor cell lines, respectively, and in five (62.5%), six (75%), five (62.5%), one (12.5%), and five (62.5%) of eight fresh tumor tissues as determined by the reverse transcription-polymerase chain reaction method. MAGE-1 or 4 protein was detected by immunoblot analysis in eight of 11 or one of one tumor cell lines, respectively, where it was expressed at the mRNA level. Major histocompatibility complex class-I antigens were expressed in 19 of 21 tumor cell lines. These results suggest that MAGE tumor-rejection antigens are expressed in substantial numbers of osteosarcomas in a major histocompatibility class-I-restricted manner.

Antigens, Neoplasm↗

PubMed1997

[Evaluation of marble burying behavior: induced alteration of monoamine metabolism in mouse brain].

Evaluation of marble burying behavior (MBB) housing-induced alteration of monoamine metabolism in mouse brain was performed by measuring metabolite levels with HPLC-ECD. Isolated housing of mice, each in a cage (22 x 32 x 14 cm; sawdust, 1-mm diameter; 5 cm in thickness) with 15 evenly spaced glass marbles on the floor (2.5-cm diameter; control, without marbles) for 24-168 hr, 5-HIAA contents were decreased in three regions: the midbrain, thalamus and hypothalamus. 5-HT turnover was not inhibited except for in the hypothalamus due to the decreases of 5-HT in the other two regions. On the other hand, DOPAC content and DA turnover were decreased in four regions: striatum, midbrain, thalamus, hypothalamus. The decrease in hypothalamic monoamine neurons was observed notably after 72 hr of MBB housing. No alterations were observed in feeding, water-drinking, spontaneous locomotor activity, number of buried marbles, serum corticosterone and serum glucose concentrations during MBB keeping compared with the control mice. These results suggested that the isolated mouse housed in a cage with evenly spaced glass marbles for a long period may be a model animal for alteration of monoamine metabolism in brain regions without physical infringement.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1997

Metabolism and acid-base status during hypoxic ventilatory depression.

The ventilatory response to acute systemic hypoxia has been thought to be determined by the balance between hypoxic stimulation via peripheral chemoreceptors and hypoxic inhibition of the respiratory neurons. In moderate-severe hypoxia, the latter predominates the former resulting in ventilatory "depression" (HVD). However, ventilation relative to metabolic rate (V.O2) during HVD is "not depressed" but remains increased because of associated reduction in O2 uptake (V.O2). The experiment presented here was conducted to elucidate the changes in CO2 output (V.CO2) and acid-base status during hypoxia and their role in ventilatory regulation. Ventilation, metabolic rate (V.O2, V.CO2), acid-base status and blood lactate concentration were measured during and after inhalation of hypoxic gases in halothane-anesthetized and spontaneously breathing rats. The HVD occurred at FIO2 0.08 with increased blood lactate concentration, increased venous PCO2 and a large drop in venous pH without significant changes in arterial pH and PCO2. Furthermore, the amount of reduction in V.CO2 during HVD was much smaller than that of V.O2 and the V.CO2/V.O2 ratio increased. These findings suggest that CO2 output becomes relatively higher than O2 consumption in moderate-severe hypoxia. The possible origin of CO2 accumulation in the venous blood, such as the buffering of lactic acid by bicarbonate, and its role in ventilatory stimulation are discussed. Since there was no large increase in V.E and metabolic rate in the post-hypoxic period, "O2 debt" during HVD was small.

Acid-Base Equilibrium↗

PubMed1997

Phorbol ester enhancement of IL-3-dependent proliferation of primitive hematopoietic progenitors of mice in culture.

Protein kinase C (PKC) is a Ca++- and phospholipid-dependent protein kinase activated by diacylglycerol that is either released from cell membranes in response to certain growth factors or mimicked by 12-O-tetradecanoyl phorbol-13-acetate (TPA). We studied the effects of TPA on interleukin-3 (IL-3)-dependent colony formation of mouse bone marrow cells from mice injected with 5-fluorouracil 2 days before examination in order to clarify the significance of PKC in the proliferation of primitive hematopoietic progenitors. Although TPA alone did not support colony formation, TPA in combination with IL-3 increased colony numbers from 1.5 to 2 times that formed with IL-3 and vehicle. TPA increased not only the granulocyte/macrophage colonies, but also the multilineage colonies. A sequential colony count showed that TPA, unlike IL-6, did not hasten the appearance of colonies. Because TPA enhanced IL-3-dependent colony formation derived from lineage-negative marrow cells obtained from mice that received 5-FU 2 days before, it is possible that it might act directly on primitive progenitors. Prolonged pretreatment of marrow cells with TPA prevented TPA-augmented colony growth. Calphostin C, a specific PKC inhibitor, and certain specific tyrosine kinase inhibitors, such as genistein and herbimycin A, abrogated the enhancing effects of TPA on IL-3-dependent colony formation. These data suggest that TPA had a direct effect on the primitive progenitors and enhanced IL-3-dependent colony formation via activation of PKC and certain tyrosine kinases.

Animals↗

PubMed1997

[Results of cardiac operation and thoracic aortic operation in patients aged 75 years or older].

A total of 121 patients aged 75 years or older underwent cardiac operation or thoracic aortic operation at our hospital between 1988 and February 1997. They were composed of 74 cases of ischemic heart disease, 22 cases of valvular disease, 1 case of myxoma, and 24 cases of thoracic aortic disease. Operative mortality rate was 13.5% in ischemic heart disease, 4.2% in valvular disease and myxoma, and 25% in thoracic aortic disease. In ischemic heart disease, the operative mortality rate was especially high in emergency operation for acute myocardial infarction. In thoracic aortic operation, further improvement should be made with regard to preoperative and intraoperative management.

Age Factors↗

PubMed1997

[Study on risk factors and late results of coronary artery bypass grafting for acute myocardial infarction].

Study was made on the operative results, risk factors, and late results of coronary artery bypass grafting (CABG) for acute myocardial infarction (AMI) conducted at our hospital. The subjects of the present study were 70 cases of AMI who underwent CABG during a period of five years from January 1991 to December 1995. They were composed of 61 males and 9 females whose mean age was 61.9 years. LMT disease was observed in 13 cases and preoperative shock in 18 cases. The mean aortic cross-clamp time was 64 minutes with the mean extracorporeal circulation time being 134 minutes and the mean number of grafts being 2.5. The mean preoperative-postoperative peak creatine kinase was 4479 IU/L. The number of operative deaths was 14 with a mortality rate of 20%. When compared with elective cases of CABG conducted during the same period with a mortality rate of 2.7%, the operative result of AMI was poor. The mortality rate by risk factor was 40% for age of 70 years or more, 46.2% for complication of LMT disease, 52.9% for preoperative shock, 58.3% for preoperative C.I. of less than 2.0, 80% for postoperative C.I. of less than 2.0, 28.2% for conduct of postoperative circulatory support, and 42.1% for peak creatine kinase of 5000 IU/L or more. Aortic cross-clamp time and reperfusion time (interval from onset of AMI to aortic declamp) were found not to be risk factors. Late death accounted for 5 cases including one case of cardiac death due to suspected AMI. Survival rate excluding operative deaths and hospital deaths was 98% in one year and 83.9% in five years. When compared to non cardiacevent cases, the survival rate of positive cardiac event cases was significantly poor. The operative results of severe myocardial ischemia cases represented by cases of complication of LMT disease were poor and it is considered that improvement of intraoperative myocardial protection and aggressive use of postoperative circulatory support are necessary in the future. The survival cases of those who could endure surgery was comparatively satisfactory, but when cardiac event developed, prognosis was poor and thus more rigid follow-up is considered to be necessary.

Age Factors↗

PubMed1996

Isolation and characterization of the gene encoding an aminopeptidase involved in the selective toxicity of ascamycin toward Xanthomonas campestris pv. citri.

An aminopeptidase gene named XAP has been isolated from Xanthomonas campestris pv. citri, a plant pathogenic bacterium. The bacterium is one of the rare micro-organisms susceptible to ascamycin, an aminoacyl nucleoside antibiotic that inhibits protein synthesis. Sequence analysis reveals that the gene encodes a 311 amino acid protein with a calculated molecular mass of 35134 Da and approx. 50% identity for amino acids to the proline iminopeptidase from Neisseria gonorrhoeae. The XAP gene product, Xap, expressed in Escherichia coli has proline iminopeptidase activity as well as ascamycin dealanylating activity in vitro.

Adenosine↗

PubMed1996

Isoform-specific intracellular vesicle formation by recombinant annexin XI-A in Sf9 cells.

Annexins are a group of structurally related proteins that bind phospholipids in a Ca2(+)-dependent manner and have the ability to self-aggregate and to promote vesicle aggregation and membrane fusion. Two isoforms of annexin XI, termed XI-A and XI-B, were previously identified by screening a bovine chondrocyte cDNA library. But little is known about differences in their biological function. In the present study, we therefore examined the results of expression of the two proteins in Spodoptera frugiperda (Sf9) insect cells, and in mammalian COS-7 cells. Annexin XI isoforms were expressed in Sf9 cells using a baculovirus expression system. Recombinant annexin XI-A but not XI-B caused formation of spherical "annexin XI-associated vesicles, " in the cytoplasm of Sf9 cells. Furthermore, indirect immnocytofluorescence studies showed similar phenomenon, that of local aggregation, with transfected annexin XI-A in COS-7 cells, whereas annexin XI-B remained diffusely distributed throughout the cytoplasm. Since annexin XI isoforms differ in amino acid sequence only in the alternative splicing region of the N-terminal domain, these findings suggest that this domain has distinct biological significance in terms of aggregation and vesicle formation.

Amino Acid Sequence↗

PubMed1996

Association between the DRB1*08032 histocompatibility antigen and methimazole-induced agranulocytosis in Japanese patients with Graves disease.

OBJECTIVE: To determine the association between HLA class II genes and methimazole-induced agranulocytosis in patients with Graves disease. DESIGN: Case-control study. SETTING: Kuma Hospital, which specializes in thyroid diseases, in Kobe, Japan. SUBJECTS: 24 patients with Graves disease who had methimazole-induced agranulocytosis diagnosed by peripheral granulocyte counts of less than 0.5 x 10(9)/L, and 68 patients with Graves disease treated with methimazole, who were free from agranulocytosis. Controls were 525 healthy, unrelated Japanese student volunteers at Kyushu University in Japan. MEASUREMENTS: All HLA class II genes were analyzed for polymorphisms at the DNA level by using the polymerase chain reaction sequence-specific oligonucleotide probes method. The allele frequencies in the agranulocytotic Graves disease group were compared with those in the nonagranulocytotic Graves disease and control groups. RESULTS: A strong positive association was seen in DRB1*08032 between the agranulocytotic group and both the control and nonagranulocytotic Graves disease groups. CONCLUSION: The HLA DRB1*08032 allele was strongly associated with susceptibility to methimazole-induced agranulocytosis, suggesting that cellular autoimmunity may be involved in its development.

Agranulocytosis↗

PubMed1996

Suppression by IL-10 and IL-4 of cytokine production induced by two-way autologous mixed lymphocyte reaction.

The immune response of T cells to self-HLA antigens on autologous non-T cells is known as the autologous mixed lymphocyte reaction (AMLR), and is defective in various diseases. We have investigated the effects of exogenous IL-10, a potential agent to treat various inflammatory diseases, on cytokine production induced by two-way AMLR in human peripheral blood mononuclear cells (PBMC). Effects of exogenous IL-4 were also investigated. IL-10 suppressed IL-6, IL-8, TNF-alpha and GM-CSF production when added at the beginning of culture and added 24 h after incubation. It abolished IL-1 alpha production only when added at the beginning of culture. IL-10 did not inhibit IL-3 production. The pattern of suppression by IL-10 of cytokine production induced by anti-CD3 mAb or PHA was similar to that induced by AMLR. Although IL-4 showed a largely similar pattern of inhibition when added at the beginning of culture, the level of inhibition was much lower than that of IL-10. IL-4 did not inhibit cytokine production when added 24 h after culture. These results indicate that IL-10, but not IL-4, is a potent inhibitor to cytokine production induced by two-way AMLR.

Cell Line↗

PubMed1996

Ca2+ signaling and intracellular Ca2+ binding proteins.

Changes in cytosolic Ca2+ concentrations evoke a wide range of cellular responses and intracellular Ca(2+)-binding proteins are the key molecules to transduce Ca2+ signaling via enzymatic reactions or modulation of protein/protein interations (Fig.1). The EF hand proteins, like calmodulin and S100 proteins, are considered to exert Ca(2+)-dependent actions in the nucleus or the cytoplasm. The Ca2+/phospholipid binding proteins are classified into two groups, the annexins and the C2 region proteins. These proteins, distributed mainly in the cytoplasm, translocate to the plasma membrane in response to an increase in cytosolic Ca2+ and function in the vicinity of the membrane. Ca2+ storage proteins in the endoplasmic or sarcoplasmic reticulum provide the high Ca2+ capacity of the Ca2+ store sites, which regulate intracellular Ca2+ distribution. The variety and complexity of Ca2+ signaling result from the cooperative actions of specific Ca(2+)-binding proteins. This review describes biochemical properties of intracellular Ca(2+)-binding proteins and their proposed roles in mediating Ca2+ signaling.

Animals↗

PubMed1996

Granulocyte-colony stimulating factor and stem cell factor are the crucial factors in long-term culture of human primitive hematopoietic cells supported by a murine stromal cell line.

The findings that murine marrow stromal cell line MS-5 supported the proliferation of human lineage-negative (Lin-) CD34+CD38- bone marrow cells in long-term culture have been reported. In this study, we analyzed this proliferating activity of MS-5-conditioned medium (CM) on human primitive hematopoietic cells. When Lin-CD34+CD38- cells of normal human cord blood cells were co-cultured with MS-5, colony forming cells (CFCs) were maintained over 7 weeks in vitro. Prevention of contact between MS-5 and Lin-CD34+CD38- cells by using membrane filter (0.45 micron) was negligible for this activity. This indicated that the activity of MS-5 on human primitive hematopoietic cells is a soluble factor(s) secreted from MS-5, which is not induced by the contact between MS-5 and Lin-CD34+CD38- cells. We tried to purify this soluble activity. An active material with a molecular weight of about 150 kDa, determined by gel filtration chromatography, solely supported the growth of Lin-CD34+CD38- cells and Mo7e, a human megakaryocytic cell line. This activity not only reacted with anti-mouse stem cell factor (mSCF) antibody on Western blots, but it was also neutralized in the presence of anti-mSCF antibody. Another active material with a molecular weight of about 20-30 kDa synergized with mSCF to stimulate the growth of Lin-CD34+CD38- cells but failed to do so alone, although this synergy was inhibited in the presence of soluble mouse granulocyte-colony stimulating factor (mG-CSF) receptor, which is a chimeric protein consisting of the extracellular domain of mG-CSF receptor and the Fe region of human IgG1. In addition, the latter molecule supported the growth of the G-CSF dependent cell line FD/GR3, which is a murine myeloid leukemia cell line, FDC-P2, transfected with mG-CSF receptor cDNA. Adding of anti-mSCF antibody and soluble mG-CSF receptor to the culture completely abrogated the activity of MS-5-CM. Recombinant (r) mSCF and rmG-CSF had synergistic activity on the growth of Lin-CD34+CD38- cells. These results indicated that the activity on Lin-CD34+CD38- cells included in MS-5-CM is based upon the synergistic effects of mSCF and mG-CSF.

ADP-ribosyl Cyclase↗

PubMed1995

Functional hierarchy of c-kit and c-fms in intramarrow production of CFU-M.

Whereas the molecular natures of M-CSF/CSF-1 and its receptor c-fms are well characterized, its actual role in the intramarrow hematopoiesis remains obscure. This is because disruption of this signaling pathway results in the osteopetrosis mouse that lacks the bone cavity for hematopoiesis. To elucidate the role of c-fms in intramarrow hematopoiesis, we produced an antagonistic monoclonal antibody to murine c-fms and investigated its expression and function in the normal bone marrow. c-fms+ cells were detected both in mature and immature hematopoietic cells. Morphologically, c-kit+c-fms-, c-kit+c-fms+ and c-kit-c-fms+ cells were medium sized blasts, large promyelocytes with azurophilic granules and mature monocytes respectively. CFU-M was 10-fold more enriched in the c-kit+c-fms- than c-kit+c-fms+ fraction. Moreover, injection of the anti c-fms antibody had no effect on the production of CFU-M in the bone marrow, while anti-c-kit mAb could deplete them. As c-kit+c-fms+ cells were readily generated in the culture of c-kit+c-fms- cells, most of the CFU-M in the bone marrow are, in fact, c-fms- cells that differentiate into c-fms+ upon culture. These observations indicate a clear functional hierarchy of c-kit and c-fms in the bone marrow. Namely, c-kit plays the primary role in the production and maintenance of CFU-M, while c-fms, though it co-expressed with c-kit and functions as the growth receptor for M-CSF in the culture, has only a minimum role in the proliferation of c-fms+ cells in the bone marrow.

Animals↗

PubMed1995

Differences in MHC class I self peptide repertoires among HLA-A2 subtypes.

To investigate how single amino acid substitutions in MHC class I molecules affect differences in peptide repertoires, we eluted and sequenced the naturally processed peptides from three HLA-A2 subtypes (HLA-A*0204, -A*0206, and -A*0207) that differ by a single amino acid residue substitution each with HLA-A*0201 at the floor of the binding groove. Allele-specific peptide motifs for each HLA-A2 subtype substantially differed from that of HLA-A*0201 in the dominant anchor residues. The relative signal intensities for 18 self peptides, determined by mass spectrometry, precisely reflected these peptide motifs. Some overlapping peptides were isolated from both HLA-A*0201 and a single HLA-A2 variant, but no peptide was ubiquitously found across all variants. To rationalize the differences in peptide motifs, possible conformations of each allele were computer modeled by energy minimization calculations based on the reported crystal structure of HLA-A*0201. According to our models, the differences in peptide motifs could be explained by substituted-residue-driven conformational changes for each MHC-peptide complex. These results demonstrate the fine differences between HLA-A2 subtype self peptide repertoires and contribute to the prediction of antigenic peptides.

Amino Acid Sequence↗

PubMed1995

Terminal differentiation of murine resident peritoneal macrophages is characterized by expression of the STK protein tyrosine kinase, a receptor for macrophage-stimulating protein.

STK, a new member of the hepatocyte growth factor receptor family, is the receptor for macrophage-stimulating protein (MSP), which acts on murine resident peritoneal macrophages. We established polyclonal and monoclonal antibodies against STK and characterized the structure of STK protein and STK expression on cells of the mononuclear phagocyte system. Western blotting showed that the STK transcript is translated into a single-chain precursor and then cleaved into a 165-kD disulfide-linked heterodimer composed of a 35-kD alpha-chain and a 144-kD beta-chain. Western blotting detected STK protein on resident peritoneal macrophages, a target of MSP, and showed that it was autophosphorylated in cells stimulated by MSP. By flow cytometric analysis using a monoclonal anti-STK antibody, we showed that STK protein is expressed on restricted macrophage populations such as resident peritoneal macrophages, but not on exudate peritoneal macrophages or mononuclear phagocytes of the bone marrow, peripheral blood, spleen, or alveoli. Resident peritoneal macrophages were classified into two fractions according to their reactivity with an anti-STK antibody and a marker antibody for macrophages: STKhigh-F4/80high cells and STKnegative-F4/80low cells. Acute exudative macrophages were all STKnegative-F4/80low, but they gradually became predominantly STKhigh-F4/80high several days after entrance into the peritoneal cavity. These results showed that after monocytes migrate into the peritoneal cavity, they undergo terminal differentiation in the peritoneal microenvironment. This is the first evidence of tissue-specific terminal differentiation of peritoneal macrophages, and this terminal differentiation can be characterized by the expression of STK receptor tyrosine kinase.

Animals↗