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Biomedical subjects

K Tezuka

Publications and source records attributed to K Tezuka.

At least 19 recordsLinked to original sources

The role of inducible co-stimulator (ICOS)/B7-related protein-1 (B7RP-1) interaction in the functional development of Peyer's patches.

T-cell co-stimulatory molecule, inducible co-stimulator (ICOS)/B7-related protein-1 (B7RP-1) interactions play an essential role of T-cell-dependent B-cell activation in peripheral lymphoid organs such as spleen and lymph nodes. Here, we investigate the role of ICOS/B7RP-1 interactions in the development of Peyer's patches (PPs). In ICOS(-/-) mice, the number of PPs was not decreased, although PPs in ICOS(-/-) mice were significantly reduced in size. Phenotypic analysis showed no obvious differences between ICOS(-/-) and ICOS(+/-) mice in the distribution of T-cells, B-cells, macrophages and dendritic cells. However, PNA(+) cells characteristic of intestinal germinal centers were totally absent in ICOS(-/-) mice. Moreover, production of IgA and IgG, but not IgM was significantly reduced in PPs in ICOS(-/-) mice. These data suggest that ICOS/B7RP-1 interactions may not affect the organogenesis, but involve in the functional development of PPs.

Animals↗

Opposing effects of anti-activation-inducible lymphocyte-immunomodulatory molecule/inducible costimulator antibody on the development of acute versus chronic graft-versus-host disease.

The functional role of inducible costimulator (ICOS)-mediated costimulation was examined in an in vivo model of alloantigen-driven Th1 or Th2 cytokine responses, the parent-into-F(1) model of acute or chronic graft-vs-host disease (GVHD), respectively. When the Ab specific for mouse ICOS was injected into chronic GVHD-induced mice, activation of B cells, production of autoantibody, and development of glomerulonephritis were strongly suppressed. In contrast, the same treatment enhanced donor T cell chimerism and host B cell depletion in acute GVHD induced host mice. Blocking of B7-CD28 interaction by injection of anti-B7-1 and anti-B7-2 Abs inhibited both acute and chronic GVHD. These observations clearly indicate that the costimulatory signal mediated by CD28 caused the initial allorecognition resulting in the clonal expansion of alloreactive T cells, whereas the costimulatory signal mediated by ICOS played a critical role in the functional differentiation and manifestation of alloreactive T cells. Furthermore, treatment with anti-ICOS Ab selectively suppresses Th2-dominant autoimmune disease.

Acute Disease↗

ICOS costimulation requires IL-2 and can be prevented by CTLA-4 engagement.

We investigated the relationship between ICOS, CD28, CTLA-4, and IL-2 to gain a better understanding of this family of costimulatory receptors in the immune response. Using magnetic beads coated with anti-CD3 and varying amounts of anti-ICOS and anti-CTLA-4 Abs, we show that CTLA-4 ligation blocks ICOS costimulation. In addition to inhibiting cellular proliferation, CTLA-4 engagement prevented ICOS-costimulated T cells from producing IL-4, IL-10, and IL-13. Both an indirect and direct mechanism of CTLA-4's actions were examined. First, CTLA-4 engagement on resting cells was found to indirectly block ICOS costimulation by interferring with the signals needed to induce ICOS cell surface expression. Second, on preactivated cells that had high levels of ICOS expression, CTLA-4 ligation blocked the ICOS-mediated induction of IL-4, IL-10, and IL-13, suggesting an interference with downstream signaling pathways. The addition of IL-2 not only overcame both mechanisms, but also greatly augmented the level of cellular activation suggesting synergy between ICOS and IL-2 signaling. This cooperation between ICOS and IL-2 signaling was explored further by showing that the minimum level of IL-2 produced by ICOS costimulation was required for T cell proliferation. Finally, exogenous IL-2 was required for sustained growth of ICOS-costimulated T cells. These results indicate that stringent control of ICOS costimulation is maintained initially by CTLA-4 engagement and later by a requirement for exogenous IL-2.

Abatacept↗

Surgical outcome of pulmonary resection in chronic necrotizing pulmonary aspergillosis.

BACKGROUND: Surgical treatment of chronic necrotizing pulmonary aspergillosis is hazardous and controversial. METHODS: Ten patients (8 men, 2 women; mean age, 50 years) with chronic necrotizing pulmonary aspergillosis underwent pulmonary resection between 1989 and 2000. Single segmentectomy or lobectomy, pneumonectomy, or bilobectomy and multisegmentectomy were performed. Clinicopathologic features of these patients were reviewed to clarify the role of surgical intervention for chronic necrotizing pulmonary aspergillosis. RESULTS: The mean time from the onset of clinical symptoms to operation was 5.3 years. Surgical intervention was undertaken because of prolonged illness in 4 patients and hemoptysis in 6 patients. All patients survived. Three major complications (1 late empyema, 2 bronchopleural fistulas) occurred in the large dead space in the right pleural cavity. All survivors were free of aspergillosis at a mean follow-up time of 4.8 years, and only 1 patient required antifungal drugs for relapse during the follow-up period. CONCLUSIONS: Aggressive pulmonary resection in chronic necrotizing pulmonary aspergillosis should be considered when patients have prolonged illness or frequent hemoptysis. Empyema and bronchopleural fistula are the main complications. Concomitant thoracoplasty or intrathoracic transposition of the chest wall musculature is recommended in cases involving a large residual pleural cavity on the right side.

Adult↗

AILIM/ICOS: its expression and functional analysis with monoclonal antibodies.

Activation-inducible lymphocyte immuno-mediatory molecule (AILIM/ICOS) is the third member of the co-stimulatory molecule CD28/CTLA-4 (CD152) family, and an inducible cell surface glycoprotein expressed on lymphocytes following activation. To determine the expression profile of the molecule, we generated monoclonal antibodies (MAbs) against human, rat, and mouse AILIM/ICOS. None of the MAbs bound to AILIM/ICOS of other species. The numbers of AILIM/ICOS-positive cells among human peripheral blood mononuclear cells (PBMC), and rat and mouse splenocytes were very low (0.5, 0.4, and 1.2%, respectively), and the cells included many CD4-positive T cells except in the case of rat. Rat AILIM/ICOS-positive cells among splenocytes included many CD45RA-positive B cells, although the expression on lymph node cells was similar to that on human PBMC and mouse splenocytes. Among rat thymocytes, the AILIM/ICOS expression was mainly localized on CD4- and CD8-double positive T cells. The binding of AILIM/ICOS to B7h-Ig, which is the ligand-Fc chimeric protein, was inhibited by all AILIM/ICOS-specific MAbs except for SG430. The potency of the co-stimulatory activity of CD3 and AILIM/ICOS as to T-cell proliferation was found to be substantial in human. Interestingly, the levels of stimulation with the two types of MAbs were equal to that with CD3 and CD28 despite the different functions of the two MAbs in the AILIM/ICOS-B7h interaction. On the other hand, the potencies in rat and mouse, although two independent MAbs were tested, were relatively lower than that of CD28-mediated co-stimulation.

Animals↗

Identification and characterization of rat AILIM/ICOS, a novel T-cell costimulatory molecule, related to the CD28/CTLA4 family.

Activation-inducible lymphocyte immuno-mediatory molecule (AILIM) is an inducible cell surface glycoprotein expressed on thymocytes and activated lymphocytes. Specific monoclonal antibody to rat AILIM induced the cell aggregation of a rat thymoma cell line and ConA-activated splenocytes. In the present study, we identified the primary structure of two species of rat AILIM by expression cloning. We also cloned mouse and human AILIM homologues and the predicted amino acid sequences were identical to those of the inducible costimulator ICOS/CRP-1, which belongs to the CD28/CTLA4 family. Although the human and mouse AILIM/ICOS molecule is localized on T-cells, the major population of AILIM/ICOS-positive cells in rat splenocyte was CD45RA-positive B-cells. The expression level of AILIM/ICOS on T-cells was relatively low; however, its expression was drastically induced by the treatment with PMA plus Ca-ionophore or the engagement of CD3 and these costimulatory molecules. Almost all T-cells exhibited potency as to its expression. Functional analysis of AILIM/ICOS demonstrated that AILIM-mediated costimulation was relatively weak compared to that of human.

Abatacept↗

Evaluation of autonomic nervous function during upper gastrointestinal endoscopy using heart rate variability.

To investigate autonomic nervous function during upper gastrointestinal endoscopy, we analyzed R-R interval variability from electrocardiograms obtained during endoscopy. Holter electrocardiogram recordings were made before and after premedication, and during endoscopy. Time- and frequency-domain analyses of heart rate variability were performed in 54 subjects premedicated with scopolamine butylbromide (SB group) and in 66 subjects premedicated with glucagon (G group). To determine the effect of autonomic imbalance on arrhythmia generation during endoscopy, subjects with arrhythmias (A group) were compared with subjects without arrhythmias (N group). In the SB group, high frequency spectral power (HF power; 0.15 to 0.40 Hz), which reflects parasympathetic activity, decreased significantly after premedication, and decreased further during endoscopy (P < 0.01). Moreover, HF power before premedication or during endoscopy in the A group was significantly lower than that in the N group (P < 0.01). This study suggests that the measurement of HF power prior to endoscopy can identify subjects with reduced HF power. This should allow the prevention of cardiovascular complications related to premedication and endoscope insertion.

Adult↗

AILIM/ICOS: a novel lymphocyte adhesion molecule.

The adhesive interaction between T cells and antigen-presenting cells is required for the formation of the immunological synapse. Inducible co-stimulator (ICOS) is a third member of the CD28 family of co-stimulatory molecules. Here we describe a novel lymphocyte adhesion molecule, of relative molecular mass 47,000, designated AILIM, that is a rat homolog of ICOS. Rat AILIM was constitutively expressed on thymocytes and was induced on naive T cells after activation. Human thymoma cells bound to purified AILIM. Furthermore, cells transfected with the AILIM gene aggregated in an AILIM-dependent manner. These results suggest a novel function for AILIM/ICOS as an adhesion molecule, which plays an important role in T cell activation.

Animals↗

Effects of CTGF/Hcs24, a product of a hypertrophic chondrocyte-specific gene, on the proliferation and differentiation of chondrocytes in culture.

Recently, we cloned a messenger RNA (mRNA) predominantly expressed in chondrocytes from a human chondrosarcoma-derived chondrocytic cell line, HCS-2/8, by differential display PCR and found that its gene, named hcs24, was identical with that of connective tissue growth factor (CTGF). Here we investigated CTGF/Hcs24 function in the chondrocytic cell line HCS-2/8 and rabbit growth cartilage (RGC) cells. HCS-2/8 cells transfected with recombinant adenoviruses that generate CTGF/Hcs24 sense RNA (mRNA) proliferated more rapidly than HCS-2/8 cells transfected with control adenoviruses. HCS-2/8 cells transfected with recombinant adenoviruses that generate CTGF/Hcs24 sense RNA expressed more mRNA of aggrecan and type X collagen than the control cells. To elucidate the direct action of CTGF/Hcs24 on the cells, we transfected HeLa cells with CTGF/Hcs24 expression vectors, obtained stable transfectants, and purified recombinant CTGF/Hcs24 protein from conditioned medium of the transfectants. The recombinant CTGF/Hcs24 effectively promoted the proliferation of HCS-2/8 cells and RGC cells in a dose-dependent manner and also dose dependently increased proteoglycan synthesis in these cells. In addition, these stimulatory effects of CTGF/Hcs24 were neutralized by the addition of anti-CTGF antibodies. Furthermore, the recombinant CTGF/Hcs24 effectively increased alkaline phosphatase activity in RGC cells in culture. Moreover, RT-PCR analysis revealed that the recombinant CTGF/Hcs24 stimulated gene expression of aggrecan and collagen types II and X in RGC cells in culture. These results indicate that CTGF/Hcs24 directly promotes the proliferation and differentiation of chondrocytes.

Adenoviridae↗

Free 4-hydroxyproline content in serum of bedridden aged people is elevated due to fracture.

Hydroxyproline (Hyp) content in biological fluids is used as a parameter of collagen catabolism, especially bone resorption. In this paper, we examined the relationship between aging and serum free 4-Hyp and proline (Pro) content using a newly introduced analytical technique which is chemiluminescence determination with electrogenerated tris (2,2'-bipyridine) ruthenium(III). Serum was collected from 50 bedridden aged people and 131 normal subjects living in Yamato-son, Amamioshima, Kagoshima. In the free 4-Hyp content of normal serum, the change in females is more gentle than that males with aging. The free 4-Hyp content of bedridden aged serum is significantly (p<0.05) elevated compared to normal aged serum. Bedridden aged females and males also show levels significantly (p<0.05) elevated in comparison to normal. These changes are due to bone resorption based on bedridden patients' atrophy. In bedridden aged people, free 4-Hyp of those with a fracture was significantly (p<0.05) elevated than in people without a fracture. No relationship between low bone density and high free 4-Hyp in serum was observed. It seems that bone resorption or bedridden atrophy may be enhanced in bedridden aged people by a fracture. In free Pro content in serum, no significant change was observed. These results show that the free 4-Hyp content in serum is useful in the clinical or biological inspection of bone resorption, especially in aged people.

Adult↗

Toward creation of a universal NMR database for the stereochemical assignment of acyclic compounds: the case of two contiguous propionate units.

[formula: see text] Using triol 1 as a representative example of natural products containing two contiguous propionate units, 13C and 1H NMR databases for the stereochemical assignment of acyclic compounds have been created. Chemical shift increments due to the presence of additional functional groups as well as solvent effects are discussed.

Databases, Factual↗

Connective tissue growth factor induces the proliferation, migration, and tube formation of vascular endothelial cells in vitro, and angiogenesis in vivo.

Connective tissue growth factor (CTGF) is a novel cysteine-rich, secreted protein. Recently, we found that inhibition of the endogenous expression of CTGF by its antisense oligonucleotide and antisense RNA suppresses the proliferation and migration of vascular endothelial cells. In the present study, the following observations demonstrated the angiogenic function of CTGF in vitro and in vivo: (i) purified recombinant CTGF (rCTGF) promoted the adhesion, proliferation and migration of vascular endothelial cells in a dose-dependent manner under serum-free conditions, and these effects were inhibited by anti-CTGF antibodies; (ii) rCTGF markedly induced the tube formation of vascular endothelial cells, and this effect was stronger than that of basic fibroblast growth factor or vascular endothelial growth factor; (iii) application of rCTGF to the chicken chorioallantoic membrane resulted in a gross angiogenic response, and this effect was also inhibited by anti-CTGF antibodies. (iv) rCTGF injected with collagen gel into the backs of mice induced strong angiogenesis in vivo. These findings indicate that CTGF is a novel, potent angiogenesis factor which functions in multi-stages in this process.

Allantois↗

Establishment of the enzyme-linked immunosorbent assay for connective tissue growth factor (CTGF) and its detection in the sera of biliary atresia.

Connective tissue growth factor (CTGF) is a mitogenic, chemotactic, and cell matrix-inducing factor for fibroblasts. We generated murine monoclonal antibodies against CTGF and established a sandwich enzyme-linked immunosorbent assay (ELISA) for detection of CTGF. By using the ELISA, we confirmed that CTGF was specifically induced in human fibroblasts by TGF-beta but not by PDGF, FGF, IGF-I, or EGF. We also found that the serum levels of CTGF were significantly correlated with the progression of hepatic fibrosis in biliary atresia. These results indicated that CTGF is potentially a useful parameter for monitoring certain types of fibrotic disorders.

Biliary Atresia↗

Demonstration of receptors specific for connective tissue growth factor on a human chondrocytic cell line (HCS-2/8).

The presence of receptors specific for connective tissue growth factor (CTGF) was demonstrated on a human chondrosarcoma-derived chondrocytic cell line, HCS-2/8. The binding of 125I-labeled recombinant CTGF to HCS-2/8 cells was inhibited by unlabeled CTGF but not by PDGF-BB or bFGF. Scatchard analysis revealed the presence of two classes of binding sites with Kd values of 18.6 and 259 nM on cells. A cross-linking study revealed the formation of 125I-CTGF-receptor complex with an apparent molecular weight of 280 kDa. The 125I-CTGF-receptor complex disappeared almost completely on the addition of unlabeled CTGF but not PDGF-BB or bFGF. In addition, the 125I-CTGF-receptor complex was immunoprecipitated with anti-CTGF antiserum but not with anti-PDGF receptor antiserum. These findings suggest that CTGF directly binds to specific receptor molecules on HCS-2/8 cells.

Binding Sites↗

Integrin beta2 (CD18)-mediated cell proliferation of HEL cells on a hematopoietic-supportive bone marrow stromal cell line, HESS-5 cells.

Cellular interactions between hematopoietic cells and stromal cells play important roles in the proliferation and differentiation of hematopoietic cells. The proliferation of a human erythroleukemia cell line, HEL cells, which can differentiate into macrophage- and megakaryocyte-like cells, and erythroid precursors was dramatically induced on coculture with a hematopoietic-supportive stromal cell line, HESS-5 cells, which can support long-term hematopoiesis in vitro without fetal bovine serum. HEL cells proliferated when they were cocultured with but not without direct cell contact. Because the coculture supernatants with direct cell contact and cytokines such as interleukins and growth factors did not exhibit growth-stimulating activity toward HEL cells, it was suggested that some molecule that has growth-stimulating activity exists on the surface of the cells. Extracellular matrix components such as fibronectin, laminin, vitronectin, and collagen did not affect the proliferation of HEL cells. An anti-CD18 monoclonal antibody, which recognizes the common beta chain of the beta2 integrin subfamily, induced dramatic proliferation of HEL cells. Moreover, the proliferation of HEL cells was inhibited by an antisense oligonucleotide of CD18 mRNA. As judged from these observations, the proliferation of HEL cells was mediated by CD18 molecules expressed on HEL cells. On the contrary, the common counter-receptor of the beta2 integrin subfamily, intercellular adhesion molecule-1, which is expressed on CHO-K1 cells, did not stimulate the growth of HEL cells. It is known that other counter molecules of the beta2 integrin subfamily, such as complement C3bi and fibrinogen, are not produced by stromal cells. These findings suggest that the proliferation of HEL cells may be induced through an interaction between a novel molecule of the beta2 integrin subfamily on HEL cells and the counter-receptor on HESS-5 cells. The beta2 integrin subfamily may regulate the growth of hematopoietic cells in hematopoiesis in vivo and/or cause the abnormal growth of leukemia cells.

Animals↗

Comparison of 16 human colon carcinoma cell lines for their expression of sialyl LeX antigens and their E-selectin-dependent adhesion.

Two anti-sialyl Lewis X (sLeX) monoclonal antibodies, mAb FH6 and mAb KM93, were analyzed by flow cytometry for their ability to bind to 16 human colon carcinoma cells. The binding profiles of these two anti-sLeX monoclonal antibodies did not correspond to each other. Three of the cell lines were reactive with mAb FH6 but not with mAb KM93. These three cell lines did not adhere to Chinese hamster ovary cells that were stably transfected with human E-selectin cDNA in an E-selectin-dependent manner. In contrast, almost all human colon carcinoma cell lines that bound to mAb KM93 adhered to cells that expressed E-selectin. These results suggest that a subtype of sLeX carbohydrate epitopes recognized by mAb FH6 do not always function as ligands for E-selectin.

Animals↗