[Application of laser technology to basic cell biology and its future].
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Animals↗
Biomedical subjects
K Tasaka
Publications and source records attributed to K Tasaka.
[Endoscopic treatment in colorectal lesions--especially on endoscopic mucosal resection].
Protruded polyps can usually be treated with conventional polypectomy technique. Slightly elevated lesions without malignant findings are treated with hot biopsy method if they are small enough (less than 5 mm). In order to treat flat or slightly depressed lesions or slightly elevated lesions larger than 5 mm, endoscopic mucosal resection (EMR) technique has been invented. Cancers confined to the mucosa or those only minimally invading the submucosa can be completely removed with this method. However, if histological analysis of the resected specimen shows that the cancer invades the submucosa massively or permeating the vessels, surgical treatment should be added, because otherwise there would be risk of cancer residue or metastasis. When a lesion is suspected to be a submucosal cancer by endoscopic findings and pit pattern analysis from the beginning, then surgical resection is the treatment of choice. Laterally spreading tumors, especially the homogeneous granular type, are good indication for EMR or endoscopic piecemeal mucosal resection (EPMR). It is important to remove the lesion completely confirming that the resection margin is covered with normal pits.
Colectomy↗
Reinforcement effect of histamine on the differentiation of murine myeloblasts and promyelocytes induced by granulocyte colony stimulating factor.
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Animals↗
Histamine-induced differentiation of eosinophilic subclone of HL-60 cells.
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Cell Differentiation↗
Schistosome eggs in the portal vein can induce tolerance.
Schistosoma japonicum lives in the portal vein and/or mesenteric vein of patients, producing numerous eggs which eventually induce multiple granulomas in the liver and the intestine. The experimental administration of Schistosoma japonicum eggs via the portal vein in the mouse induces tolerance both in the footpad reaction and granuloma formation in the lung. Thus, the presence of Schistosoma japonicum in the portal vein is beneficial to the parasites, not only for receiving enriched nutrition from the blood of the portal vein, but also for inducing immunological tolerance in the hosts. However, prior intravenous injection of gadolinium chloride abolishes such tolerance, indicating the role of Kupffer cells in the induction of tolerance via the portal vein.
Animals↗
Simultaneous measurements of exocytosis and intracellular calcium concentration with fluorescent indicators in single pituitary gonadotropes.
Previously, we established a method for the estimation of exocytosis in single gonadotropes using an impermeable fluorescent membrane probe, TMA-DPH. In this study, we have developed a method for the simultaneous measurement of exocytosis and intracellular free Ca2+ concentration ([Ca2+]i) by double-labeling with TMA-DPH and the intracellular Ca2+ probe, Fura-2/AM, using a fluorescence microscope with a 3-wavelength excitation and 2-wavelength emission system. We, therefore, clarified the relationship between spontaneous [Ca2+]i oscillation or gonadotropin releasing hormone (GnRH)-induced intracellular Ca2+ mobilization and exocytosis in gonadotropes. Under resting conditions, some gonadotropes showed various types of spontaneous [Ca2+]i oscillations, while others did not, but all showed basal exocytosis. Each [Ca2+]i peak oscillation did not cause Ca(2+)-regulated exocytosis, and even complete blockage of the [Ca2+]i increase by the intracellular Ca2+ chelator BAPTA/AM had no effect on basal exocytosis. Both GnRH-induced intracellular Ca2+ mobilization and regulated exocytosis showed a similar pattern of peaks and plateaus. Blockage of the [Ca2+]i increase by BAPTA/AM almost completely inhibited the GnRH-stimulated exocytosis. These results show that spontaneous [Ca2+]i oscillations under resting conditions are not linked to regulated or basal exocytosis, and that intracellular Ca2+ mobilization is essential for GnRH-stimulated exocytosis.
Animals↗
cDNA sequence analysis and characterization of a cytokine-inducing monoclonal antibody derived from autoimmune MRL/MP-lpr/lpr mouse.
We have previously reported that a monoclonal antibody 1D11 derived from an autoimmune MRL/Mp-lpr/lpr (MRL/lpr) mouse induced synthesis or increased production of IL-3, IL-6, and TNF-alpha in the IL-3-dependent bone marrow-derived cell line FDC-P2/185-4. In this report, we analyzed a sequence of cDNA encoding the V region of 1D11, and found that VH and VL segments of 1D11 belonged to the J558 and V kappa 21 family, respectively. The nucleotide sequence of 1D11 in the VH segment was highly homologous to that of AM9, a monoclonal RF derived from MRL/lpr mouse, and the only difference was the replacement of 3 nucleotides in the framework region 1 (FR1). However, the deduced amino acid sequence of 1D11 was identical to that of AM9. In contrast with the VH segment, the sequences of the VL regions of these two antibodies were quite different from each other; 1D11 showed a 3 base deletion in the FR2 and a 24 base insertion in the FR3 compared with AM9. At present, the mechanisms of such insertions or deletions in the FRs of autoantibodies are almost unknown. It is generally accepted that the differences in specificity and affinity of these autoantibodies depend on differences of CDR sequence. However, it is possible that not only CDRs but also FRs of autoantibodies play a critical role in pathogenicity and/or specificity in autoimmune diseases.
Amino Acid Sequence↗
Mouse growth hormone-releasing factor secretion is activated by inhibin and inhibited by activin in placenta.
We investigated the effects of activin and inhibin on the regulation of mouse growth hormone-releasing factor (mGHRF) secretion by primary placental cells harvested at Day 12 of pregnancy. Activin-A, an activator of FSH secretion, inhibited mGHRF secretion. In contrast, inhibin, an inhibitor of FSH secretion, activated mGHRF secretion. The lowest concentrations of activin-A and inhibin that significantly affected mGHRF secretion were 2 nM. Follistatin, a binding protein of activin, completely eliminated the ability of activin to inhibit mGHRF secretion. The steady-state level of mGHRF mRNA, as assessed by Northern analysis, was reduced by incubation of placental cells with activin-A. All activin and inhibin subunit mRNAs were expressed in mouse placenta, and their expressions increased during gestation. These findings suggest that activin and inhibin have opposite effects on mGHRF secretion as compared with FSH secretion and that they regulate mGHRF secretion in an autocrine or paracrine manner in the mouse placenta in vivo.
Activins↗
Expression of messenger ribonucleic acid for epidermal growth factor (EGF), transforming growth factor-alpha (TGF alpha), and EGF receptor in human amnion cells: possible role of TGF alpha in prostaglandin E2 synthesis and cell proliferation.
The amnion plays important structural and functional roles in the maintenance of pregnancy and the initiation of parturition. Recently, we reported that epidermal growth factor (EGF) activates prostaglandin (PG) production and cell growth in cultured amnion cells. In this study, we showed the expression of EGF, transforming growth factor-alpha (TGF alpha), and EGF receptor protein and messenger ribonucleic acid in amnion cells, using an immunofluorescence technique and the reverse transcription-polymerase chain reaction. Next, we studied the effect of TGF alpha on intracellular Ca2+ mobilization and PGE2 production in amnion cells. TGF alpha induced an increase in the intracellular Ca2+ concentration in amnion cells, and this increase was significantly reduced when the cells were incubated with cobalt chloride (a Ca2+ channel blocker; 2.5 mmol/L) or EGTA (a Ca2+ chelator; 5 mmol/L). TGF alpha enhanced PGE2 production, and this increase was significantly inhibited when the cells were incubated with indomethacin (a cyclooxygenase inhibitor; 10 mumol/L), cobalt chloride (2.5 mmol/L), or EGTA (5 mmol/L). We also investigated the effect of TGF alpha on the growth of cultured human amnion cells by using flow cytometric analysis of the DNA content. TGF alpha induced DNA synthesis by human amnion cells, and indomethacin inhibited the TGF alpha-induced DNA synthesis. These results suggest that 1) EGF/TGF alpha are expressed and produced in amnion cells; 2) these endogenous factors may regulate the proliferation of amnion cells in an autocrine or paracrine manner; and 3) these growth factors may exert their effects via intracellular Ca2+ mobilization and PGE2 production.
Amnion↗
Scanning electron microscope assessment of exocytotic changes in purified gonadotropes.
These studies were undertaken to characterize the exocytotic changes in purified gonadotropes by three-dimensional imaging using scanning electron microscopy. Rat gonadotropes were purified using a fluorescence-activated cell sorter and an argon laser treatment system. The purified gonadotropes were stimulated with GnRH under various conditions and fixed for scanning electron microscopy. After the GnRH stimulation, many 'hole' structures (diameter 0.1-0.5 micron) were observed on the cell surface, and notably the population of cells with 10 or more holes was clearly increased. The pattern of the time-course of the changes in this population was perfectly consistent with the LH secretory profile of pituitary cells, and their formation of the cells with 10 or more holes was completely inhibited by pretreatment with a GnRH antagonist. Our data suggest that the hole structure represents an exocytotic opening site and that regulated exocytosis in purified gonadotropes can be evaluated by scanning electron microscopy. This method may be widely applicable to other endocrine cells.
Animals↗
Activin inhibits but inhibin activates mouse placental lactogen-II secretion.
The regulation of mouse placental lactogen (mPL)-I and mPL-II secretion by activin and inhibin and the expression of activin and inhibin subunit mRNAs in the mouse decidua were examined. Activin-A at a concentration of 10 nM/l significantly inhibited mPL-II secretion by placental cells from days 9 and 12 of pregnancy. However, activin-A did not affect mPL-I secretion by cells from days 7 and 9 of pregnancy nor mPL-II secretion by cells from day 7 of pregnancy. By contrast, 10 nM/l inhibin activated mPL-II secretion by cells from day 12 of pregnancy. These effects of activin and inhibin on mPL-II secretion were dose-dependent. Follistatin, which binds to activin and blocks its bioactivity, completely eliminated the inhibitory effect of activin on mPL-II secretion. Incubation of placental cells from day 12 of pregnancy with activin-A resulted in a significant reduction of the mPL-II mRNA level assessed by Northern blot analysis. Northern blot analysis using poly(A)+RNA extracted from the decidua indicated that mouse decidua, as well as the placenta, express all activin and inhibin subunits and that their gene expressions increased during gestation. The expression of these mRNAs in the decidua was much higher than those in the placenta. These findings suggest that activin and inhibin regulate mPL-II secretion and suggest the presence of an autocrine or paracrine regulation of mPL-II secretion in mouse placenta by activin and inhibin after mid-pregnancy in vivo.
Activins↗
Effect of loratadine on immediate and delayed type hypersensitivity reactions.
Loratadine (CAS 79794-75-5) was effective in inhibiting the contractions of the ileum induced by histamine in guinea pigs. The drug also caused an anti-acetylcholine, anti-serotonin and anti-leukotriene D4 (LTD4) effect. In addition, loratadine inhibited the synthesis of leukotrienes more potently than ketotifen. On the other hand, in in vitro studies of histamine release from rat peritoneal mast cells induced by compound 48/80 or lung fragments in actively sensitized guinea, pigs, loratadine elicited a significant inhibition at a concentration of 5 mumol/l. In ex vivo studies, the drug inhibited histamine release from lung fragments induced by concanavalin A, and significant effect lasted for 24 h when the drug was administered at a dose of 20 mg/kg. The drug inhibited LTD4 release as well as histamine from lung fragments in actively sensitized guinea pigs. Loratadine inhibited not only 45Ca uptake into the rat peritoneal mast cells but also Ca2+ release from the intracellular Ca store induced by compound 48/80 or A23187. Loratadine increased cAMP content in rat lung preparation while decreasing cGMP content. Loratadine caused no significant change in order parameter and phospholipase A2 activity. The drug was more potent than ketotifen and terfenadine in inhibiting antigen-induced increase in airway resistance in guinea pigs. In addition, the effect of loratadine on airway resistance was sustained for 12 h. Loratadine inhibited an increase in dye leakage into the nasal cavity in rats.(ABSTRACT TRUNCATED AT 250 WORDS)
Acetylcholine↗
Implantation and growth of epidermal growth factor (EGF) receptor expressing human ovarian cancer xenografts in nude mice is dependent on EGF.
BACKGROUND: The importance of epidermal growth factor (EGF) receptor-dependent growth has not been clarified for in vivo growth of primary human ovarian cancers. METHODS: Seventeen primary human ovarian cancer tissue samples were examined for the presence of EGF receptors by a 125I-EGF-binding study. Three groups of mice were inoculated with EGF receptor expressing and not-expressing cancer tissues. The groups were as follows: control group, Sx group (mice that underwent sialoadenectomy; EGF depleted mice), and Sx+EGF (EGF-replaced) group. The ability of the inoculated tissues to implant and grow then was studied. RESULTS: Of the 17 primary ovarian cancers, 12 expressed EGF receptors and 5 did not. Eight of 12 EGF-receptor expressing cancer tissues implanted and formed growing tumors in control animals. None implanted in the Sx animals. Epidermal growth factor receptor-expressing cancers implanted in Sx animals that received EGF administration. Two of five EGF receptor-negative ovarian cancers implanted and grew in both control and Sx animals. CONCLUSION: Growth of EGF receptor-expressing primary human ovarian cancers may be dependent on EGF in vivo.
Animals↗
Characterization of activin A-, activin AB- and activin B-responding cells by their responses to hypothalamic releasing hormones.
Activin A-, AB- and B-responding cells were characterized by their responsiveness in cytosolic free calcium ([Ca2+])i) to four hypothalamic releasing hormones, CRH, GHRH, TRH and GnRH. First, rat pituitary cells responding to activin A, AB and B in [Ca2+]i were determined in a mixed population of pituitary cells. The populations of the activin A-, AB-, and B-responding cells were 13.9%, 9.3% and 13.2%, respectively. Overlapping of response among each population of activin- responding cells was present in some of the cells. The cells responding to activin A, AB, and B were then characterized by their responses to CRH, GHRH, TRH and GnRH. Most of the cells responding to activin A, AB, and B also responded to GHRH or TRH. These results reveal that there are distinct differences among each population of activin A-, AB- and B-responding cells and that there is still functional overlapping of responsiveness among these populations. The characterization of activin-responding cells suggests involvement of somatotropes and lactotropes in activin-induced biological events in the pituitary.
Activins↗
Tumor necrosis factor-alpha (TNF-alpha) inhibits expression of mouse placental lactogen-II through TNF-alpha type-I but not type-II receptor.
The aim of this study was to determine whether TNF-alpha inhibits mPL-II secretion through TNF-RI or TNF-RII, and to investigate the gestational profile of TNF-RI and TNF-RII gene expression. The mouse trophoblast cells from day 12 pregnancy were cultured with or without agonistic polyclonal antibodies directed against the individual TNF-alpha receptors, and mPL-II secretion in the medium was assessed by RIA. Anti-TNF-RI antibody significantly inhibited the mPL-II secretion in a dose- and time-dependent manner, but anti-TNF-RII antibody did not. Moreover, the TNF-RII antibody did not influence the inhibitory effect of the TNF-RI antibody on mPL-II secretion. TNF-RI antibody inhibited the mPL-II gene expression by Northern blot analysis. Amount of the gene expression of TNF-RI in the second half of pregnancy was higher than those in the first half of pregnancy both in vitro and in vivo, although the gene expression of TNF-RII was not detectable by Northern blot analysis using poly(A)+RNA. These results suggest that TNF-RI is a main receptor for TNF-alpha in mouse placenta and that TNF-alpha may have an important role in regulating mPL-II secretion after midpregnancy.
Animals↗
Characterization of rat pituitary cells by their responses to hypothalamic releasing hormones.
Rat pituitary cells in monolayer culture were characterized by their [Ca2+]i responses to hypothalamic releasing hormones, growth hormone (GHRH), thyrotropin-releasing hormone (TRH), gonadotropin-releasing hormone (GnRH) and corticotropin-releasing hormone (CRH). The percentages of the cell population responding to GHRH, TRH, GnRH, CRH and non-responding cells were 27.3%, 47.6%, 13.8%, 6.2% and 35.3%, respectively. Some of the cells responded to two or more of those hormones. In the GHRH-responding cells, the population of TRH-responding cells was 51.4%, In the TRH-responding cells, the population of GHRH-responding cells was 30.8%. Some of the GHRH-responding cells also responded to CRH and GnRH. In the GnRH-responding cells, the population of TRH-responding cells was 61.8%. In summary, GHRH-responding cells have an especially close relationship with TRH-responding cells, and GnRH-responding cells also have close relationship with TRH-responding cells. There is also some relationship between the populations responding to other pairs of releasing hormones. These findings suggest functional overlapping among each population of pituitary cells.
Animals↗
Inhibitory effect of interleukin-2 on histamine release from rat mast cells.
Interleukin-2 (IL-2) inhibited histamine release from rat mast cells induced by compound 48/80 in a concentration-dependent manner. The inhibitory effect of IL-2 on histamine release was also dependent on the length of the incubation period; the maximum inhibition was achieved at 8 h after IL-2 addition. Furthermore, IL-2 inhibited not only IP3 production but also 45Ca uptake in mast cells stimulated by compound 48/80. Since IL-2 enhanced [3H]-leucine uptake into mast cells, this suggests that protein synthesis may be related in some way with the inhibition of histamine release. IL-2 treatment augmented the synthesis of a protein having a molecular weight of approximately 35 kDa. From Western blotting analysis, it became clear that the production of lipocortin-I was augmented in rat mast cells by IL-2 treatment. The present study shows that IL-2 induces the synthesis of lipocortin-I in mast cells and that lipocortin-I may play some role in inhibiting histamine release from mast cells.
Animals↗
Lateral movement of mast cell surface protein detected by gold-labeled anti-IgE and its relation with fodrin.
Rat mast cells were incubated with gold-conjugated concanavalin A and the movement of gold particles was observed using a polarization microscope. In resting cells, the movement of gold particles was very slow. When cells were stimulated with compound 48/80, the gold particles rapidly moved laterally, unrelated to granule extrusion. When sensitized mast cells were stimulated with gold-conjugated anti-IgE (anti-IgE-gold), patching of anti-IgE-gold was also observed. Immunofluorescence microscopy of rat mast cells stained with anti-fodrin antibody and rhodamine-phalloidin revealed that both fodrin and actin exist beneath the cell membrane forming a complicated network. After stimulation of the cells with anti-IgE-gold, the fodrin network was disrupted and thin fluorescence was observed homogeneously on the cell surface. By means of Western blotting, alpha-fodrin was detected in the membrane fraction of mast cells at the 240 kDa protein band. From the present study, it is suggested that disruption of the fodrin network may occur in association with the process leading to mast cell degranulation.
Animals↗