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T Kono

Publications and source records attributed to T Kono.

At least 217 records · Page 12Linked to original sources
PubMed1992

[An injury of the liver caused by ischemia-reperfusion in rat liver. Report 2: Relationship between the damage of the liver and during the period of reperfusion].

Liver injury by 30-min ischemia following reperfusion was examined biochemically and histopathologically. A greater increase in the level of LDH was observed after 1-hr reperfusion. However, the level of LDH decreased in proportion to the period of reperfusion, while the levels of GOT and GPT were also increased rapidly and reached its peak at 12 hr following reperfusion and were almost restored to the control level by 48 hr. A similar increase was obtained in the lipid peroxides of the liver. In addition, cyt. P-450 content and NADPH cyt. c reductase activity decreased in proportion to the period of reperfusion up to 12 hr and then recovered by 96 hr. On the other hand, heme oxygenase activity was significantly increased by ischemia-reperfusion. The ischemia-reperfused liver resulted in various morphological changes with the period of reperfusion. The destruction of Disse's space, vacuolization of the cytoplasm and nonviable hepatocytes were observed after 12-hr reperfusion. These results indicate the greatest damages of the liver induced by 30-min ischemia following reperfusion is observed after 12-hr or 24-hr reperfusion. The liver injury by ischemia-reperfusion could be a useful experimental model to develop for future studies.

Alanine Transaminase↗
PubMed1992

Development of mouse enucleated oocytes receiving a nucleus from different stages of the second cell cycle.

The influence of the stage of the cell cycle of donor nuclei on the development of mouse oocytes enucleated at telophase I was examined. After nuclear transplantation and activation, a high proportion of the oocytes remodelled a nucleus, emitted a polar body and formed a pronuclear-like nucleus. Most of the reconstituted embryos that received an interphase nucleus 30-32 h or 34-36 h after treatment with human chorionic gonadotrophin (hCG) arrested at the 2-cell stage. The reconstituted embryos were able to develop to blastocysts when nuclei from late 2-cell embryos (44-46 and 48-50 h after hCG) were transferred to the oocytes. The resulting blastocysts were transferred to recipients and ten live young were obtained from the embryos that formed a pronuclear-like nucleus after extrusion of a polar body. Thus, the developmental ability of the reconstituted embryos was critically influenced by the stage of the cell cycle of the donor nuclei.

Animals↗
PubMed1992

[Histopathological study of retinopathy of prematurity].

Using light and electron microscopy, we studied the histopathological findings of retinopathy of prematurity (zone II, stage 3). The infant was born at 32-week gestational period and the birth weight was 1,255 g. He suffered from intracranial hemorrhage and hydrocephalus, and died at 78 days old. The ophthalmoscopic findings of both eyes at 72 days after birth showed that the intermedia was clear. The optic disc and posterior pole showed normal findings. Ridge formation with non-vascularized retina was seen at the equator of all quadrants of the fundus except the nasal quadrant of retina. Light and electron microscopic studies showed the following; in the most periphery of the vascularized retina, endothelial cell proliferation with the capillary lumen of glomeruloid tufts (rearguard) were seen. There were the aggregation of immature mesenchymal cells (vanguard) near to the rearguard. The cytoplasmic organelles of spindle cells in the non-vascularized retina were different from those of surrounding glial cell. Therefore, they were thought to be mesenchymal cells in the non-vascularized retina. Between the vanguard and the rearguard, the proliferative tissues composed of immature endothelial cells and mesenchymal cells extended into the vitreous body through the inner limiting membranes, and they formed the fibrovascular membranes on the retina. It was concluded that fibrovascular proliferation on the retinal surface in the active case of retinopathy of prematurity was composed of immature endothelial cells with vascular lumen and mesenchymal cells.

Humans↗
PubMed1991

Double immunohistochemical detection of transmitter phenotype of proliferating cells using bromodeoxyuridine.

We describe a new method that can determine transmitter phenotype of proliferating nerve cells at a given age. The procedure is based on indirect sequential double antigen immunofluorescence histochemistry for transmitter-synthesizing enzymes (glutamic acid decarboxylase and tyrosine hydroxylase) and the thymidine analogue, bromodeoxyuridine. The method permits simple, rapid, and effective anatomical detection, and promises to reduce certain limitations inherent in a combination with tritiated thymidine autoradiography. Employing this technique, we observed that many striatal cells expressing gamma-aminobutyric acid (GABA) and nigral cells expressing dopamine undergo the final mitosis at embryonic days 13-14 in the rat.

Animals↗
PubMed1991

A novel monoclonal antibody against murine IL-2 receptor beta-chain. Characterization of receptor expression in normal lymphoid cells and EL-4 cells.

A mAb specific for the murine IL-2R beta-chain (IL-2R beta) was produced by immunizing a rat with a rat transfectant cell line expressing a large number of cDNA-encoded murine IL-2R beta. The mAb, designated TM-beta 1, is specifically reactive with the murine IL-2R beta cDNA-transfectant but not with the recipient cell, and immunoprecipitates murine IL-2R beta of Mr 75 to 85 kDa. TM-beta 1 mAb completely abolished the high affinity IL-2 binding by inhibiting the ligand binding to IL-2R beta. Murine IL-2R beta was found to be constitutively expressed on a subpopulation of CD8+ T cells and almost all NK1.1+ NK cells in the spleen, whereas TM-beta 1 mAb inhibited the proliferation of spleen cells induced by 1 nM of IL-2. Interestingly, EL-4 cells that express murine IL-2R beta as detected by TM-beta 1 mAb can bind neither human nor murine IL-2 under the intermediate affinity conditions, although cDNA-directed human IL-2R beta expressed in the same EL-4 cells has been previously shown to manifest the intermediate affinity IL-2 binding. These results may imply that functional expression of IL-2R beta is differentially regulated between humans and mice. Finally, our neutralizing anti-IL-2R beta mAb TM-beta 1 will be useful not only for various in vitro studies but also for in vivo studies to directly investigate the possible involvement of the IL-2/IL-2R pathway in the generation and differentiation of T lymphocytes and NK cells.

Animals↗
PubMed1991

Effects of okadaic acid on insulin-sensitive cAMP phosphodiesterase in rat adipocytes. Evidence that insulin may stimulate the enzyme by phosphorylation.

Okadaic acid, a potent inhibitor of Type 1 and Type 2A protein phosphatases, was used to investigate the mechanism of insulin action on membrane-bound low Km cAMP phosphodiesterase in rat adipocytes. Upon incubation of cells with 1 microM okadaic acid for 20 min, phosphodiesterase was stimulated 3.7- to 3.9-fold. This stimulation was larger than that elicited by insulin (2.5- to 3.0-fold). Although okadaic acid enhanced the effect of insulin, the maximum effects of the two agents were not additive. When cells were pretreated with 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7), the level of phosphodiesterase stimulation by okadaic acid was rendered smaller, similar to that attained by insulin. In cells that had been treated with 2 mM KCN, okadaic acid (like insulin) failed to stimulate phosphodiesterase, suggesting that ATP was essential. Also, as reported previously, the effect of insulin on phosphodiesterase was reversed upon exposure of hormone-treated cells to KCN. This deactivation of previously-stimulated phosphodiesterase was blocked by okadaic acid, but not by insulin. The above KCN experiments were carried out with cells in which A-kinase activity was minimized by pretreatment with H-7. Okadaic acid mildly stimulated basal glucose transport and, at the same time, strongly inhibited the action of insulin thereon. It is suggested that insulin may stimulate phosphodiesterase by promoting its phosphorylation and that the hormonal effect may be reversed by a protein phosphatase which is sensitive to okadaic acid. The hypothetical protein kinase thought to be involved in the insulin-dependent stimulation of phosphodiesterase appears to be more H-7-resistant than A-kinase.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1991

Left ventricular shape as a determinant of functional mitral regurgitation in patients with severe heart failure secondary to either coronary artery disease or idiopathic dilated cardiomyopathy.

The relation between left ventricular (LV) shape and functional mitral regurgitation (MR) was evaluated in 39 patients with congestive heart failure. Heart failure was due to coronary artery disease in 23 patients (group I) and to idiopathic dilated cardiomyopathy in 16 (group II). LV shape was quantitated based on the ratio of LV major-to-minor axis and LV sphericity index calculated at end-systole and end-diastole. In group I, 9 patients had angiographic evidence of MR and 14 did not. In group II, 10 patients had MR and 6 did not. Within each group, there were no differences between patients with and without MR with regard to LV chamber volume and regional segmental wall motion abnormalities. In both groups, however, a significant difference was observed between patients with and without MR with respect to end-systolic and end-diastolic LV shape indexes. In group I, the end-systolic major-to-minor axis ratio was lower in patients with (1.42 +/- 0.04) than without (1.72 +/- 0.05) MR (p less than 0.001). Similar differences were observed in group II (1.41 +/- 0.06 vs 1.69 +/- 0.04) (p less than 0.01). In group I, the end-systolic sphericity index was also greater in patients with (0.32 +/- 0.02) than without (0.25 +/- 0.01) MR (p less than 0.02). Similar differences were observed in group II (0.37 +/- 0.03 vs 0.26 +/- 0.01) (p less than 0.02). These data indicate that in patients with severe heart failure, functional MR is present in those who manifest a more spherical LV cavity.

Cardiomyopathy, Dilated↗
PubMed1991

Interaction of the IL-2 receptor with the src-family kinase p56lck: identification of novel intermolecular association.

In the interleukin-2 (IL-2) system, intracellular signal transduction is triggered by the beta chain of the IL-2 receptor (IL-2R beta); however, the responsible signaling mechanism remains unidentified. Evidence for the formation of a stable complex of IL-2R beta and the lymphocyte-specific protein tyrosine kinase p56lck is presented. Specific association sites were identified in the tyrosine kinase catalytic domain of p56lck and in the cytoplasmic domain of IL-2R beta. As a result of interaction, IL-2R beta became phosphorylated in vitro by p56lck. Treatment of T lymphocytes with IL-2 promotes p56lck kinase activity. These data suggest the participation of p56lck as a critical signaling molecule downstream of IL-2R via a novel interaction.

Adult↗
PubMed1991

An assay system for the modulators of plasminogen activation on the cell surface.

Plasminogen activation on the cell surface is regulated by a variety of modulators which balance surface-bound plasminogen activators (PAs) and plasminogen activator inhibitors (PAIs). In this study, we developed as assay system to assess modulation of cell-associated plasminogen activation. Plasmin generation by endogenous plasminogen activators was measured with a combination of exogenously added plasminogen and a chromogenic substrate, S-2251, in the presence of living cells. A cell surface PA activity was quantitated by adopting a rate of plasmin generation. We used HT-1080, a human fibrosarcoma cell line, as representative of cells which have both PAs and PAIs on their cell surface. A basal level of cell surface PA activity was specifically reduced by anti-urokinase-type PA IgG and enhanced by anti-PAI-1 IgG, suggesting that the basal level is determined by a balance between uPA and PAI-1 on the cell surface. We examined effects of dexamethasone and thrombin on cell surface PA activity in the assay system. Dexamethasone appeared to suppress the cell surface PA activity by enhancing de novo synthesis of PAI-1, whereas thrombin suppressed it by inactivating single-chain urokinase-type plasminogen activators. These results indicate that our assay system can be adapted for the screening of various types of PA modulators.

Cell Membrane↗
PubMed1991

Evidence that protein kinase C may not be involved in the insulin action on cAMP phosphodiesterase: studies with electroporated rat adipocytes that were highly responsive to insulin.

Partially permeabilized rat adipocytes with a high responsiveness to insulin were prepared by electroporation and used to study the effect of 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7) on insulin actions in adipocytes. H-7 is a well-documented inhibitor of several protein kinases, including protein kinase C; however, it does not rapidly enter adipocytes protected with the intact plasma membrane. The cells were suspended in Buffer X [4.74 mM NaCl, 118.0 mM KCl, 0.38 mM CaCl2, 1.00 mM EGTA, 1.19 mM Mg2SO4, 1.19 mM KH2PO4, 25.0 mM Hepes/K, 20 mg/ml bovine serum albumin, and 3 mM pyruvate/Na, pH 7.4] and electroporated six times with a Gene-Pulser (from Bio-Rad) set at 25 microF and 2 kV/cm. In cells electroporated as above, insulin stimulated (a) membrane-bound, cAMP phosphodiesterase approximately 2.6-fold when the hormone concentration was 10 nM and (b) glucose transport activity approximately 4.5-fold when the hormone concentration was raised to 100 nM. H-7 strongly inhibited the actions of insulin on both glucose transport (apparent Ki = 0.3 mM) and cAMP phosphodiesterase (apparent Ki = 1.2 mM) in electroporated adipocytes. H-7 also inhibited lipolysis in adipocytes; the apparent Ki value for the reaction in intact cells was 0.45 mM, and that in electroporated cells was 0.075 mM. It is suggested that a certain protein kinase or kinases that are significantly sensitive to H-7 may be involved in the insulin-dependent stimulation of glucose transport and that of phosphodiesterase. However, protein kinase C (or Ca2+/phospholipid-dependent protein kinase) may not be involved, at least, in the hormonal action on phosphodiesterase since the apparent Ki value of H-7 for the reaction is too high.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1991

Production of identical twin and triplet mice by nuclear transplantation.

Transplantation of a single nucleus from two- or four-cell embryos into one of the enucleated blastomeres of a two-cell embryo resulted in successful production of identical triplet and twin mice. The proportion of reconstituted embryos that developed in blastocysts was 71% (84/118) when four-cell embryos were used as donors of nuclei; 10 sets of quadruplet and nine sets each of triplet and twin blastocysts were obtained by this technique. After transfer to recipients, 30% (18/61) developed to term, and one set of identical triplet and four sets of identical twin mice were obtained. When two-cell embryos were used as donors of nuclei, 79 (95%) sets of twin embryos developed to blastocysts. Of 38 twin blastocysts transferred to recipients, 21 sets (55%) developed to term as identical twin mice. These results demonstrate that the enucleated two-cell embryo develops in vitro after transfer of a nucleus from a two- or four-cell embryo and the resultant blastocyst has high potential for development to term after transfer to a recipient.

Animals↗
PubMed1991

Development of vitrified mouse oocytes after in vitro fertilization.

Mouse oocytes were cryopreserved by the vitrification method using vitrification solution (VSI) and the effects of dilution methods were examined on the rate of in vitro and in vivo development. Eighty-three percent and 75% of vitrified oocytes exhibited normal morphology when diluted in glycerol + sucrose and sucrose alone, respectively. In contrast, only 35% of the oocytes diluted by a stepwise method exhibited a normal appearance. A high proportion of vitrified oocytes was fertilized in vitro (84-94%), 80 to 87% of which were normal. Of the later embryos, 69 to 78% developed to blastocysts after 4 days of culture. Thirty-six live young (51%) were obtained when vitrified oocytes were transferred to recipient females. The overall rate of development to live young was 25% when vitrified oocytes were diluted with glycerol + sucrose solution. These results indicate that the simple and rapid procedure of vitrification and glycerol + sucrose dilution is suitable for the cryopreservation of mouse oocytes.

Animals↗
PubMed1991

Effect of tretinoin on collagen gel contraction induced by mouse 3T3 fibroblasts.

Balb/3T3 fibroblasts were cultured in type I collagen gel and the effects of tretinoin (all-trans-retinoic acid) were examined on cell growth and the gel contraction produced by cells. Cell proliferation was suppressed and the degree of gel contraction was enhanced by the addition of 10(-7) and 10(-6) M tretinoin. Growth and gel contractility of transformed cells derived from the Balb/3T3 cells were not influenced by this agent. Addition of 12-O-tetradecanoylphorbol ester, which is known to antagonize tretinoin in several biological processes, enhanced gel contraction synergistically with tretinoin. These results suggest that tretinoin influences cell-to-collagen interactions.

Animals↗
PubMed1991

The effect of combinations of cefotiam and other antibiotics on methicillin-resistant Staphylococcus aureus in vitro.

The in-vitro activities of cefmetazole, flomoxef, imipenem, vancomycin and enramycin alone and in combination with cefotiam against eighteen clinically isolated methicillin-resistant Staphylococcus aureus was investigated. Cefotiam, cefmetazole, flomoxef and imipenem inhibited the growth of clinical isolates at concentrations ranging from 100 to 1600, 6.25 to 400, 6.25 to 400 and 0.78 to 200 mg/L, respectively. Synergic effects were observed with combinations of cefotiam and cefmetazole, flomoxef or imipenem against more than 70% of the strains. The fractional inhibitory concentration (FIC) index values were less than 0.1. Vancomycin and enramycin alone inhibited the growth of all strains at concentrations ranging from 0.39 to 1.56 mg/L and 0.2 to 0.78 mg/L, respectively. Moreover, vancomycin and enramycin in combination with cefotiam showed synergy against strains in which no synergic effects were observed when cefotiam was combined with other beta-lactam agents. About 50% of the strains tested were inhibited synergically by cefmetazole, flomoxef or imipenem, at clinically relevant concentrations in combination with 0.78 mg/L of cefotiam. The effects of vancomycin or enramycin in combination with cefotiam on the growth of a homogeneous resistant clone, which was derived from one of the clinical isolates, TS-65, was also studied. Regrowth in the presence of vancomycin or enramycin alone was suppressed when cefotiam was added.

Cefotiam↗
PubMed1991

Effects of butylated hydroxyanisole on ornithine decarboxylase activity and its gene expression induced by phorbol ester tumor promoter.

Butylated hydroxyanisole (BHA) is a phenolic antioxidant that has been found to suppress the activity of skin tumor promoters. In this study, we investigated the effect of BHA on the activity of ornithine decarboxylase (ODC, an indicator of tumor promotion) and its gene expression induced by 12-O-tetradecanoyl-phorbol-13-acetate (TPA) in mouse skin. TPA-induced ODC activity was markedly inhibited by the topical application of 55 mumol of BHA (the inhibition rate at 6 h was about 80%). In Northern and dot-blot analysis, the TPA-induced increase in ODC mRNA was shown to be markedly reduced by the same dose of BHA (the inhibition rate at 4 h was about 60%). These results suggest the involvement of a decrease in ODC gene expression in the mechanism of the inhibition of ODC activity by BHA.

Animals↗
PubMed1991

Differential effects of cyclosporine A on ornithine decarboxylase activity induced by ultraviolet-B and PUVA in mouse skin.

The inhibitory effect of cyclosporine A (CsA) on the activity of ornithine decarboxylase (ODC) induced by phorbol ester tumor promoter has been reported. In the present study, the effects of CsA on ODC activity induced by ultraviolet-B (UV-B) and PUVA in the skin of the SKH/hr 1 hairless mouse were investigated. Topical application of CsA (1.7 mumol) to the dorsal skin irradiated with 50 mJ/cm2 UV-B did not remarkably change ODC activity. On the other hand, if CsA was applied simultaneously with 3 J/cm2 UV-A 1 h after treatment with 0.3% 8-methoxypsoralen, PUVA-induced ODC activity was suppressed by about 60% at 12 and 24 h after UV-A irradiation. In the dot blotting analysis of ODC-specific mRNA level, a significant but slight decrease in ODC mRNA level (about 20% inhibition) was observed in the PUVA-treated group compared with the control group (vehicle and UV-A). The inhibition of PUVA-induced ODC activity by CsA may have been caused in part by the decrease in ODC mRNA level and in part by a post-transcriptional regulation mechanism.

Animals↗
PubMed1991

Alteration of cartilagenous proteoglycan in psoriasis.

Articular tissue was obtained at surgery for a femoral neck fracture in a patient with psoriasis without arthritis. The proteoglycan of the cartilage of the sample was analysed biochemically. Normal cartilage is known to produce two types of proteoglycan monomers (fast- and slow-sedimenting groups), which are distinguishable by density-gradient ultracentrifugation. In the psoriatic cartilage analysed in the present study, it was shown that the former group was absent and only the latter group remained.

Cartilage, Articular↗