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Biomedical subjects

N Takakura

Publications and source records attributed to N Takakura.

At least 55 records · Page 3Linked to original sources
PubMed1999

[A case of local recurrence of rectal cancer responding to local intraarterial infusion therapy].

A 42-year-old male developed pain in the right gluteal region due to local recurrence after curative resection of advanced lower rectal cancer. Radiotherapy (60 Gy) was performed, but satisfactory results were not obtained. Therefore, a reservoir was placed lowing cannulation of the internal iliac artery. The chemotherapy, in addition to intravenous administration of low dose CDDP (20 mg), included local intraarterial infusion therapy with 5-FU (1,500 mg/5 hour) once per week. After 10 courses of this chemotherapy (total dose: CDDP, 200 mg; 5-FU, 15,000 mg), the pain decreased, and the tumor size was reduced without side effects, improving the patient's QOL. At present, multidisciplinary treatments including such chemotherapy and radiotherapy is performed for local recurrence of rectal cancer, but adequate results are often not obtained. Local intraarterial infusion chemotherapy via the internal iliac artery accompanied by changes in blood flow can be safely performed on an outpatient basis, and appears to be effective for local recurrence of rectal cancer.

Adenocarcinoma↗
PubMed1999

Circulating levels of soluble CD30 and other markers in colorectal cancer patients.

In a search for new biologic serum tumor markers with prognostic value we evaluated the soluble form of the CD30 (sCD30), a marker of cells producing T helper 2 (Th2)-type cytokines, interleukin-1 receptor antagonist (IL-1ra), soluble interleukin-2 receptor (sIL-2R), soluble tumor necrosis factor -type I, -type II (sTNF-R55, -75) and immunosuppressive acidic protein (IAP) in patients, with advanced colorectal cancer. The data showed that abnormal levels of sCD30 were detected in eight (80.0%) out of ten patients. In contrast, sCD30 levels were not detected in healthy volunteers. The relationship between sCD30, sIL-2R and IAP were positively correlated. In contrast, sCD30 and IL-1ra were negatively correlated. These results suggested that IL-1ra may play a role, at least in part, to inhibit CD30 release, and sCD30 appears to be a new biologic serum tumor marker of possible use in the clinical setting of cancer patients.

Adult↗
PubMed1999

Hyperammonemia induced by administration of glucose and insulin after hepatopancreatectomy in rats.

Massive resection of both the liver and pancreas is performed as a radical procedure in some cases of advanced biliary cancer, but it has been reported that this disease is frequently complicated by hyperbilirubinemia or hepatic insufficiency postoperatively, which is a serious hindrance to performing such extended surgery (Nimura et al., 1991; Nakamura et al., 1992). To investigate the pathogenesis of hepatic dysfunction after hepatopancreatectomy, we performed 4 surgical procedures consisting of 68% hepatectomy, 90% pancreatectomy, 68% hepatectomy plus 90% pancreatectomy (hepatopancreatectomy) and sham-surgery in rats. Then, rats were continuously infused with 5% or 20% glucose solution at a constant speed (50 mL/day) for 24 hours in the fasting state, thus creating a total of 8 groups. During infusion of 20% glucose solution into rats with pancreatectomy or hepatopancreatectomy, insulin (1 U/5 g glucose) was added to the solution to adjust the blood glucose. In rats infused with 20% glucose solution with added insulin after hepatopancreatectomy, the blood glucose level did not differ, but adenosine 5'-triphosphate (ATP) and energy charge levels in the liver tissue were significantly lower, while the blood ammonia level was significantly higher than those in the other 7 groups. These results demonstrate that continuous infusion of high concentrations of glucose solution with added insulin after hepatopancreatectomy in rats reduces hepatic mitochondrial function, resulting in hyperammonemia due to reduced urea synthesis.

Alanine↗
PubMed1998

Tyro 3 receptor tyrosine kinase and its ligand, Gas6, stimulate the function of osteoclasts.

Bone is continuously being formed and resorbed. This process is accomplished by the precise coordination of two cell types: osteoblasts and osteoclasts. Osteoclasts are large, multinucleated cells that are derived from the same hematopoietic precursors as macrophages. However, these bone-resorbing cells are difficult to study directly because of their relative inaccessibility. The purification of primary osteoclasts from rabbit bones by their adherent nature provides an opportunity for investigating the molecules in osteoclasts. We have examined the expression of receptor tyrosine kinase by polymerase chain reaction (PCR) and found that Tyro 3 was frequently identified from primary osteoclasts in PCR cloning. Immunohistochemistry revealed that Tyro 3 was expressed on the multinucleated osteoclasts which were positive for tartrate-resistant acid phosphatase (TRAP), but not on mononuclear TRAP-positive cells. The Tyro 3 ligand, Gas6, induced the phosphorylation of Tyro 3 receptors in osteoclasts in two to five min. Gas6 and protein S directly enhanced the bone resorbing activity of mature osteoclasts. This effect of Gas6 was inhibited by the addition of a tyrosine kinase inhibitor, herbimycin A. However, Gas6 did not affect the differentiation of osteoclasts from bone marrow cells. Gas6 and protein S are dependent on vitamin K, a cofactor for the enzyme responsible for carboxylation of glutamic acid residues. The findings in this study are the first to indicate a new biological activity of Gas6 and protein S as a direct regulator of osteoclastic function; they give an insight into the role of these vitamin K-dependent ligands in bone resorption in vivo.

Acid Phosphatase↗
PubMed1998

Characterization of TEK receptor tyrosine kinase and its ligands, Angiopoietins, in human hematopoietic progenitor cells.

TEK, or TIE-2, is a receptor tyrosine kinase (RTK) that is known as a functioning molecule of vascular endothelial cells. TEK comprises a subfamily of RTK with TIE, and these two receptors play critical roles in vascular maturation, maintenance of integrity and remodeling. We generated mAb against the extracellular domain of human TEK protein to elucidate its expression pattern in human hematopoietic cells. Flow cytometric analysis of bone marrow cells revealed that TEK was expressed in 27% of CD34+ cells, 20% of c-KIT+ cells and 26% of CD34+CD38- cells, indicating that TEK is expressed in a subset of primitive hematopoietic stem cells (HSC). TEK was also expressed in 20% of CD19+ B lymphocytes but not in other lineage-committed cells. Progenitor assays in methylcellulose culture showed that CD34+TEK+ cells formed significantly less BFU-E and CFU-Mix than CD34+TEK- cells, but there was no difference in the number of CFU-GM between these two populations. Two recently identified TEK ligands, termed Angiopoietin-1 and -2, bound to TEK with similar affinities, and Angiopoietin-1 effectively induced TEK phosphorylation in hematopoietic cells. Angiopoietin-2 also induced a low level of TEK phosphorylation and weakened the phosphorylation induced by Angiopoietin-1, suggestive of an elaborate regulator of the TEK-TEK ligand signaling pathway. Although neither ligands affected the proliferation of TEK-transfected hematopoietic cells or the colony formation of CD34+TEK+ bone marrow cells, both promoted the adhesion of TEK-transfected hematopoietic cells to a collagen matrix or a layer of bone marrow stromal cells. These findings indicate that the TEK-TEK ligand signaling pathway is regulated in a refined manner and is involved in hematopoietic cell-microenvironment interaction.

Angiopoietin-1↗
PubMed1998

Essential role of platelet-derived growth factor receptor alpha in the development of the intraplacental yolk sac/sinus of Duval in mouse placenta.

Platelet-derived growth factor receptor alpha (PDGFRalpha) is expressed in multiple tissues and exerts its function throughout mouse embryogenesis. Upon screening the PDGFRalpha-expressing tissues in mouse embryos by immunohistochemistry using our established monoclonal antibody against murine PDGFRalpha, we found its expression in an epithelium lining a sinusoidal structure in placenta. This structure was proven to be the sinus of Duval, and the PDGFRalpha-positive epithelium to be the intraplacental yolk sac (IPY). The IPY has been postulated to be a derivative of primitive endoderm because of its morphology and its expression of vitamin D-dependent 9-kDa calcium-binding protein, and to play some roles in materno-fetal transport. In this study, we demonstrated that the IPY develops from primitive endoderm by its invagination into chorioallantoic placenta and continues to strongly express PDGFRalpha until the prenatal stage. Moreover, we found that the IPY is completely absent in PdgfraPh/PdgfraPh mutant embryos, which lack the Pdgfra gene, suggesting that the function of PDGFRalpha is essential to its formation. Hence, PDGFRalpha expressed in the IPY should be listed as a component of the cytokine network of murine placental development.

Animals↗
PubMed1998

Can POSSUM, a scoring system for perioperative surgical risk, predict postoperative clinical course?

POSSUM, a Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity, is a scoring system which assesses perioperative surgical risks (Copeland GP et al.: Br J Surg, 1991, Vol 78, 356-360). The POSSUM scoring system consists of two categories of assessment to assess the risk of surgery. A 12-factor (age, cardiac status, pulse rate, systolic blood pressure, respiratory status, Glasgow Coma Score, serum concentration of urea, potassium and sodium, hemoglobin concentration, white cell count and findings on electrocardiography) and 4-grade physiological score (PS) were developed. This was combined with a 6-factor (type of surgical procedure, number of procedures, blood loss, peritoneal soiling, presence of malignancy and mode of surgery) and 4-grade operative severity score (OSS). The present paper attempts to validate it retrospectively. Postoperative hospitalization period and duration of antibiotics administration were both significantly correlated with OSS, but not with PS. These results suggest that the POSSUM scoring system is useful for predicting the postoperative clinical course.

Adult↗
PubMed1998

Is increased IL-1 beta mRNA expression in spleen of tumor-bearing mice relevant to cancer cachexia?

Using C3H/He mice bearing MH-134 tumor cells, cytokine inductions of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and interferon-gamma (IFN-gamma) were determined in spleens by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Levels of IL-1 beta were significantly (p<0.05) increased in the spleens of tumor-bearing mice compared with those of freely fed control animals. In contrast, no significant increase of other cytokine mRNAs was observed. In addition, constitutive levels of IL-1 beta mRNA were present in spleens of tumor-bearing mice during the experimental period. These results suggest that the over-expression of IL-1 beta mRNA was relevant to clinical manifestations of cancer-burden states.

Animals↗
PubMed1998

Soluble intercellular adhesion molecule-1 and natural killer cell activity in gastric cancer patients.

Intercellular adhesion molecule-1 (ICAM-1), a molecule bound to the cell surface, is a ligand for leukocyte function antigen-1 (LFA-1), and the ICAM-1/LFA-1 system mediates various cell-cell interactions involved in immunity. Soluble ICAM-1 (sICAM-1) is a circulating substance and binds with LFA-1 of leukocytes, thus, making leukocytes less available for binding with cell surface ICAM-1 on target cells. The serum level of soluble ICAM-1 (sICAM-1) was found to be significantly elevated (p<0.01) in patients with early and advanced gastric cancer compared with healthy controls. Natural killer activity (NK activity) was assessed by measuring the cytotoxicity of peripheral blood mononuclear cells (PBMCs) for K562 cells. There was no significant difference in NK activity between gastric cancer patients and healthy controls when heat-inactivated fetal calf serum was used in assays. However, addition of patient serum significantly decreased (p<0.05) NK activity when the serum was from patients with advanced gastric cancer compared with healthy volunteers. Addition of anti-ICAM-1 monoclonal antibody 0 to 5.0 microg/ml caused little change in NK activity in healthy controls, but its addition at 10 microg/ml remarkably decreased NK-activity in gastric cancer patients, probably through antibody binding with ICAM-1 on target cells. In other experiments, liver metastasis was induced in mice by inoculation of colon 26 murine colon cancer cells. In vitro pretreatment of colon 26 cells with the anti-ICAM-1 monoclonal antibody significantly increased the number of metastatic nodules. These results suggest that both sICAM-1 and anti-ICAM-1 monoclonal antibody act as immunosuppressive factors by inhibiting the ICAM-1/LFA-1 system.

Adult↗
PubMed1998

Effect of streptococcal lyzate OK-432 on peripheral blood mononuclear cells in gastric cancer patients.

OK-432, a killed preparation of Streptococcus pyogenes, as well as Bacillus Calmette-Guerin (BCG) and Corynebacterium parvum are all known biological response modifiers. To examine the immunomodulatory effects of OK-432, natural killer cell activity and cytokine production by peripheral blood mononuclear cells (PBMCs) were assessed in 32 patients with gastric cancer. Skin tests for Streptococcus pyogenes A-3Su (Su-PS) and BCG were performed in all patients. Other nutritional and immunological parameters were also determined. OK-432-treated PBMCs showed a significant increase of cytotoxicity against K562 cells (p < 0.01). Increased levels of interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha) and interleukin-2 (IL-2) were found in the supernatants of cultures treated with OK-432 in 29 (90.6%), 20 (62.5%), and 8 (25.0%) out of 32 patients, respectively. Natural killer cell activity, IFN-gamma production, and the Su-PS skin test were positively correlated (p < 0.01). In contrast, the BCG test and other markers were not correlated with natural killer cell activity and IFN-gamma production. These results suggest that the Su-PS skin test could predict OK-432-induced natural killer cell activity and IFN-gamma production in patients with gastric cancer, and was therefore useful to determine whether patients were responders to OK-432.

Adjuvants, Immunologic↗
PubMed1997

Stepwise requirement of c-kit tyrosine kinase in mouse ovarian follicle development.

Ovarian follicle development is controlled by the cycling variation of gonadotrophins derived from the central nervous system. Intragonadal signals are also required, especially in the autonomous development of small follicles. Receptor tyrosine kinase c-kit and its ligand SLF (Steel factor) are expressed on the surface of specific populations of follicle-forming cells in a contiguous manner and are thought to have important roles in follicular development. We blocked the interaction of c-kit and its ligand by administering the function-blocking antibody ACK2 to developing mice at various times after birth and monitored ovarian follicle development. A blockade of c-kit function disturbed the onset of primordial follicle development, primary follicle growth, follicular fluid formation of preantral follicles, and penultimate-stage ovarian follicle maturation before ovulation. Ovarian follicle growth was dependent on c-kit during the first 5 days after birth when the functional FSH receptor is not yet expressed in mouse ovary. In contrast, primordial follicle formation and survival, small preantral or antral follicle development, ovulation, and luteinization of the ovulated follicle were not affected by this antibody. These findings indicate the stepwise requirement of c-kit and its ligand interaction system in the developing ovarian follicle and that c-kit with its ligand supports the autonomous development of ovarian follicle independent of gonadotrophins.

Animals↗
PubMed1997

Expressions of PDGF receptor alpha, c-Kit and Flk1 genes clustering in mouse chromosome 5 define distinct subsets of nascent mesodermal cells.

In gastrulating embryos, various types of cells are generated before differentiation into specific lineages. The mesoderm of the gastrulating mouse embryo represents a group of such intermediate cells. PDGF receptor alpha (PDGFRalpha), c-Kit and fetal liver kinase 1 (Flk1) are expressed in distinctive mesodermal derivatives of post-gastrulation embryos. Their expressions during gastrulation were examined by whole mount immunostaining with monoclonal antibodies against these three receptors. The antibodies stained different mesodermal subsets in gastrulating embryos. Flow cytometry of head fold stage embryos revealed that Flk1+ mesodermal cells could be further classified by the level of c-Kit expression. To examine the possibility that hematopoietic cell differentiation is initiated from the Flk1+ mesoderm, embryonic stem (ES) cells were cultured on the OP9 or PA6 stromal cell layer; the former but not the latter supported in vitro hematopoiesis from ES cells. Flk1+ cells were detected only on the OP9 cell layer from day 3 of differentiation before the appearance of hematopoietic cells. Thus, Flk1+ cells will be required for in vitro ES cell differentiation into hematopoietic cells. The results suggest that these three receptor tyrosine kinases will be useful for defining and sorting subsets of mesodermal cells from embryos or in vitro cultured ES cells.

Animals↗
PubMed1997

PDGFR alpha expression during mouse embryogenesis: immunolocalization analyzed by whole-mount immunohistostaining using the monoclonal anti-mouse PDGFR alpha antibody APA5.

We investigated the cells that express platelet-derived growth factor receptor alpha (PDGFR alpha) during mouse embryogenesis. PDGFR alpha expression has been identified by in situ hybridization or immunohistochemistry using polyclonal antibodies on tissue sectins. Because no immunostaining study using whole-mount specimens has been published to date, we established a new monoclonal antibody (MAb), APA5, for this purpose. Our results differed in that APA5 stained only the paraxial mesoderm, whereas other investigators concluded that most if not all mesodermal cells expressed PDGFR alpha. Moreover, we did not find PDGFR alpha expression in embryonic erythrocytes, which have been previously suggested to express PDGFR alpha. On the basis of our present results, we wish to revise the proposed PDGFR alpha expression as follows. At the pregastrulation stage, PDGFR alpha is expressed only in primitive endoderm, particularly that in the ectoplacental cone. On gastrulation, it is expressed at high levels in the paraxial mesoderm. This expression continues after its differentiation into the somite. Along with the differentiation and migration of the sclerotome, PDGFR alpha + cells begin to become distributed throughout the embryonal mesenchyme. During organogenesis, particularly intense staining is detected in regions of epithelial and mesenchymal interaction, such as the tooth bud and bronchi. In addition to mesodermal derivatives, the developing lens, apical ectodermal ridge, glial precursor, cardiac valves, and choroid plexus express PDGFR alpha. Our results with whole-mount immunostaining show that PDGFR alpha is abundantly expressed and may play important roles during embryogenesis.

Animals↗
PubMed1997

In vitro analysis of potency restriction during epiblast differentiation.

During mammalian gastrulation, posterior part of primitive ectoderm differentiates into subsets of mesoderm cells, the most proximal portion of which subsequently gives rise to vascular endothelial cells and hematopoietic cells. To analyze this process in which the potency of multipotent epiblast cells is restricted progressively into hematopoietic cell lineages, we have established a culture system that allows differentiation of epiblast cells as well as embryonic stem cells into hematopoietic cells. Using this culture system, we showed that all parts of epiblast tissues at early streak and late bud stages preserved hematogenic potency, while it was lost from anterior region at early head fold stages. However, this loss of hematogenic potency in the anterior region of the head fold stage embryo was reinduced by addition of activin in the culture. Moreover, in order to detect transitory stages of mesoderm cells that are the direct progeny of multipotent epiblast cells, we developed three monoclonal antibodies that are able to define distinct subsets of mesoderm cells in the gastrulating embryo. These results are discussed from a view of cell-mass based commitment.

Animals↗
PubMed1996

Preferential proliferation of murine colony-forming units in culture in a chemically defined condition with a macrophage colony-stimulating factor-negative stromal cell clone.

The establishment of culture conditions that selectively support hematopoietic stem cells is an important goal of hematology. In this study, we investigated the possibility of using for this purpose a defined medium, mSFO2, which was developed for stromal cell-dependent bone marrow cultures. We found that a combination of epidermal growth factor (EGF), the OP9 stromal cell line, which lacks macrophage colony-stimulating factor, recombinant stem cell factor, and the chemically defined medium mSFO2 provides a microenvironment where c-Kit+ Thy-1+/lo Mac-1+/lo B220- TER119- common beta + IL-2R gamma + gp130+ cells are selectively propagated from normal, unfractionated bone marrow cells. This cell population produced an in vitro colony at a very high efficiency (50%), whereas it has only limited proliferative ability in the irradiated recipient. Thus, the cells selected in this culture condition might represent colony-forming units in culture (CFU-c) with short-term reconstituting ability. Transferring this cell population into medium containing differentiation signals resulted in the rapid production of mature myelomonocytic and B cell lineages in vitro and in vivo. The fact that a similar culture condition was created by erb-B2-transduced OP9 in the absence of EGF indicated that EGF exerts its effect by acting on OP9 rather than directly on CFU-c. These results suggested that the balance between self-renewal and differentiation of CFU-c can be regulated by extra-cellular signals.

Animals↗
PubMed1996

Defects of B-cell lymphopoiesis and bone-marrow myelopoiesis in mice lacking the CXC chemokine PBSF/SDF-1.

The chemokines are a large family of small, structurally related cytokines. The physiological importance of most members of this family has yet to be elucidated, although some are inducible inflammatory mediators that determine leukocyte chemotaxis. Pre-B-cell growth-stimulating factor/stromal cell-derived factor-1 (PBSF/SDF-1) is a member of the CXC group of chemokines PBSF/SDF-1 stimulates proliferation of B-cell progenitors in vitro and is constitutively expressed in bone-marrow-derived stromal cells. Here we investigate the physiological roles of PBSF/SDF-1 by generating mutant mice with a targeted disruption of the gene encoding PBSF/SDF-1. We found that mice lacking PBSF/SDF-1 died perinatally and that although the numbers of B-cell progenitors in mutant embryos were severely reduced in fetal liver and bone marrow, myeloid progenitors were reduced only in the bone marrow but not in the fetal liver, indicating that PBSF/SDF-1 is responsible for B-cell lymphopoiesis and bone-marrow myelopoiesis. In addition, the mutants had a cardiac ventricular septal defect. Hence, we have shown that the chemokine PBSF/SDF-1 has several essential functions in development.

Animals↗
PubMed1996

The p53 gene is a potent determinant of chemosensitivity and radiosensitivity in gastric and colorectal cancers.

We previously reported that introduction of the wild-type p53 gene into human cancer cells with deleted p53 enhanced apoptosis induced by chemotherapy [Fujiwara et al. (1994) Cancer Res 54:2287]. This suggests that p53 status could be a potent determinant of the therapeutic efficacy of DNA-damaging cancer therapy. We analyzed 24 patients with gastric or colorectal cancer for p53 mutations and apoptotic changes in surgical specimens. Out of 11 patients with gastric cancer, 3 were treated with chemotherapeutic drugs before resection; 5 of 13 patients with colorectal cancer had 30 Gy radiation prior to surgery. p53 mutations were detected in 4 cases of gastric cancer (36.4%) and in 6 cases of colorectal cancer (46.2%) by immunohistochemical staining. The preoperative DNA-damaging therapies increased the number of apoptotic cells in wild-type-p53-expressing tumors; tumors with mutant p53, however, significantly showed fewer apoptotic cells compared with those expressing wild-type p53. The p53-inducible WAF1/CIP1 protein was immunohistochemically observed in wild-type-p53-containing tumors, whereas mutant-p53-expressing tumors expressed no detectable WAF1/CIP1. Taken together, we conclude that p53 mutations are associated with the poor response of chemotherapy and radiotherapy.

Adult↗