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Y Shiba

Publications and source records attributed to Y Shiba.

At least 73 records · Page 4Linked to original sources
PubMed1990

Effects of ATP depletion with DL-ethionine on biliary excretion of indocyanine green in the rat.

To clarify the energy-dependency of biliary excretion of a diagnostic dye, the effect of ATP depletion on biliary excretion was investigated. Biliary excretion of indocyanine green (ICG) in rat liver reached a maximum 20 min after intravenous application. The level of ATP in the liver was lowered to 35.4% of the control value about 5 h after administration of DL-ethionine (100 mg/100 g body weight). The rate of bile flow and the amount of ICG excreted in initial 10 min into the bile of ethionine-treated rats were lowered to 67.5% and 61.3% of the control values, respectively. The amount of ICG excreted for 10 min from 30 min to 40 min after application of ICG in ethionine-treated rats was comparable to that of the control. The level of ICG in blood 5 min after application of ICG was raised by 59.2% of the control value. These results suggest that ATP depletion in the liver caused by treatment with ethionine suppresses the initial rate of uptake and biliary excretion of ICG.

Adenosine Triphosphate↗
PubMed1990

Sex-related differences in drug-metabolizing enzyme activity of rats in carrageenan-induced inflammation.

Sex related differences in drugs metabolizing enzymes was studied using Wistar-rats bearing carrageenan-induced edema. One day after treatment with carrageenan, aminopyrine N-demethylase activity was inhibited in males but not in females. Carrageenan treatment did not alter the activity of aniline hydroxylase in either sex of the rats. These data show that there is a sex-related difference in the ability of carrageenan to alter the hepatic drug metabolism, which is substrate specific, in the rat.

Animals↗
PubMed1989

Enhanced binding of fibronectin-coated latex beads to quiescent 3T3-L1 cells is correlated with escape from growth arrest.

The possible involvement of fibronectin receptors in growth stimulation was investigated by an analysis of fibronectin-coated latex bead binding to 3T3-L1 cells under various conditions. 3T3-L1 cells, growth-arrested in a medium with a low concentration of calf serum, bound few fibronectin-coated beads. After addition of serum at concentrations of 1.0% or higher, there was a rapid and transient increase in the number of cells with bound beads and a subsequent increase in the incorporation of bromodeoxyuridine (BrdU) into cell nuclei. Incorporation of BrdU was observed in about 60% of the cells with bound beads. Fibroblast growth factor and platelet-derived growth factor at concentrations of 5 ng/ml or higher also enhanced binding of fibronectin-coated beads to cells. Stimulation of bead binding by epidermal growth factor and insulin was weak. Fibroblast growth factor, but not epidermal growth factor, increased the incorporation of BrdU into nuclei. These results indicate a relationship between stimulation of cell proliferation in quiescent cells and increased binding by cells of fibronectin-coated latex beads.

Animals↗
PubMed1989

Close relationship between modulation of serum-induced stimulation of DNA synthesis and changes in gap-junctional intercellular communication in quiescent 3T3-L1 cells caused by cyclic AMP and the tumor-promoting phorbol ester TPA.

Involvement of gap-junctional intercellular communication in the stimulation of growth was investigated in quiescent 3T3-L1 cells. When the cells in monolayer were growth-arrested by culture in a low concentration of calf serum, addition of dibutyryl cyclic AMP enhanced dye-coupling and suppressed the enhancement of DNA synthesis, induced by calf serum, in quiescent cells. 12-O-Tetradecanoylphorbol-13-acetate (TPA) suppressed dye-coupling in quiescent cells and enhanced DNA synthesis in both quiescent and serum-treated cells. When about 5000 cells were cultured in contact to form a colony, growth arrest of the cells was observed in the central region of such colonies rather than in the peripheral region, but addition of calf serum induced DNA synthesis in the cells in both the peripheral and central regions of the colonies. Addition of TPA enhanced serum-induced DNA synthesis in the cells in the central region of colonies rather than in the peripheral region. These results suggest that the ability of quiescent cells to escape from growth arrest is inversely correlated to the extent of gap-junctional intercellular communication.

Animals↗
PubMed1989

Herbimycin A suppresses the reduction of gap-junctional intercellular communication induced by tumor-promoting phorbol ester in 3T3-L1 cells.

We have examined the suppressive effect of herbimycin A on the reduction of gap-junctional intercellular communication that is induced by a tumor-promoting phorbol ester in 3T3-L1 cells. Most cells in growth arrest participated in dye-coupling, as evaluated by the transfer between cells of a fluorescent dye (Lucifer Yellow CH). Treatment of cells with 0.25 microgram/ml herbimycin A slightly enhanced the dye-coupling. This enhancement required treatment for periods as long as 24 h. Addition of 100 ng/ml 12-O-tetradecanoylphorbol-13-acetate (TPA) caused a rapid reduction of dye-coupling. However, addition of TPA did not suppress dye-coupling in cells pretreated for more than 24 h with herbimycin A. Pretreatment of cells for less than 6 h with herbimycin A did not suppress the TPA-induced reduction of dye-coupling. These results suggest that herbimycin A suppresses the reduction of gap-junctional intercellular communication that is induced by TPA through enhancement of the ability of the cells to participate in gap-junctional intercellular communication.

Animals↗
PubMed1989

The different effects of type I and IV collagens on the survival and proliferation of cultured BSC-1 cells.

The effects of type I and IV collagens on the survival and proliferation of cells were investigated to clarify a possible involvement of the substratum in the regulation of cell function. BSC-1 cells attached, spread and sustained their viability in the absence of calf serum on culture dishes coated with type IV collagen, but were unable to spread and survive on untreated culture dishes. The effects of adding type IV collagen in solution were similar to those of type IV coating. The fraction of the solution of type IV collagen with molecular mass of more than 100 kDa enhanced spreading and survival of cells, but the fraction of less than 100 kDa did not. Type I collagen did not support cell viability in the absence of calf serum. Moreover, coating of culture dishes with type I collagen, but not with type IV collagen, inhibited DNA synthesis and cell proliferation in the presence of calf serum. The cells grown on type I collagen were long, thin and spindle-shaped, and their stress fibers were not well developed, but the cells grown on type IV collagen, as well as those grown on untreated culture dishes, were polygonal in shape with well-developed stress fibers. These results indicate that the interactions of BSC-1 cells with the substratum, when it is derived from type I and IV collagens, differentially modulate the survival and proliferation of BSC-1 cells.

Animals↗
PubMed1989

Survival of 3T3-L1 cells induced by fibroblast growth factor depends on cell density and adhesion to the substratum.

The effects of cell contacts and the attachment of cells to the substratum on growth-factor-induced survival of 3T3-L1 cells were investigated to clarify their involvement in the maintenance of cell viability. When 3T3-L1 cells in low-density cultures or in high-density cultures were harvested with EDTA solution and cultured in the absence of calf serum, almost all cells from the low-density cultures lost viability 24 h later. However, about 15% of the cells harvested from high-density cultures survived for 24 h in the absence of calf serum. Addition of calf serum also enhanced the survival of cells from high-density cultures to a much greater extent than that of cells from low-density cultures. Addition of fibroblast growth factor enhanced the survival of cells, especially in the case of cells from high-density cultures. However, epidermal growth factor and platelet-derived growth factor failed to enhance survival. Coating of cultures dishes with vitronectin slightly enhanced cell survival. Addition of fibroblast growth factor markedly enhanced the survival of cells on the dishes coated with vitronectin or with fibronectin, but not on the dishes coated with heat-denatured bovine serum albumin. These results suggest that fibroblast growth factor promotes survival of 3T3-L1 cells, depending on cell to-cell contacts during prior culture and on the adhesion of cells to the substratum.

Animals↗
PubMed1989

Modulation of survival and proliferation of BSC-1 cells through changes in spreading behavior caused by the tumor-promoting phorbol ester TPA.

The effect of a tumor-promoting phorbol ester on spreading behavior was investigated to clarify the involvement of the interactions between cells and substratum in the maintenance of cell viability and the control of cell proliferation. BSC-1 cells did not spread and lost cell viability after a 24-h incubation in the absence of calf serum. Addition of calf serum initially induced radial spreading and then polarized spreading, with the formation on stress fibers and focal contact-like structure, and enhanced survival. Vitronectin also induced both radial spreading and polarized spreading, and enhanced cell survival. 12-O-Tetradecanoylphorbol-13-acetate (TPA) induced radial spreading with actin ribbons in the absence of serum. It improved the survival of cells attached to the substratum, but not in suspension. TPA suppressed polarized spreading, formation of stress fibers and of focal contact-like structure, and cell proliferation, in the presence of serum. Phorbol did not have any effect. These results suggest that enhancement of radial spreading and inhibition of polarized spreading of BSC-1 cells by TPA are closely related to the enhancement of cell survival and inhibition of cell growth.

Animals↗
PubMed1989

Relationship between the number of sperms and the rate of implantation in bitches inseminated into unilateral uterine horn.

Studies were made on the number of sperms required for fertilization of ova ovulated from the bilateral ovaries in bitches. The experiment was carried out with 44 female beagles, which were divided into four groups of seven to eleven bitches each. The four groups were inseminated with 40 X 10(6) sperms/0.2 ml, 20 X 10(6) sperms/0.1 ml, 10 X 10(6) sperms/0.1 ml, and 3-5 X 10(6) sperms/0.1 ml, respectively. All the bitches were laparotomized at an optimum time for mating and inseminated at the tip of the horn of an unilateral uterus. In the four groups conception took place at a rate of 7/7, 8/8, 10/11, and 2/7, respectively. The number of puppies exceeded the number of ova ovulated on the inseminated side at a rate of 5/7, 6/8, 0/10, and 0/2 in the four groups, respectively. Therefore, it was clarified that when more than 20 X 10(6) sperms/0.1 ml were inseminated in the ipsilateral uterine horn, ova ovulated on the contralateral side were fertilized also. Then a unilateral ovary was ovariectomized in 11 bitches, which were inseminated with 10 X 10(6) sperms/0.1 ml in the ipsilateral uterine horn. As a result, only one bitch became conceptive and gave birth to only one puppy. From these results, it was considered that 10 X 10(6) sperms/0.1 ml may be most adequate for the ova on the side of insemination alone to be fertilized.

Animals↗
PubMed1989

Autonomic control of intercellular communication in salivary glands.

Effects of autonomic agonists, antagonists and denervation on intercellular communication between cells in acini of rat submandibular glands were investigated to clarify the regulation and maintenance of intercellular communication by the autonomic nervous system. Addition of acetylcholine (ACh) and adrenaline rapidly and reversibly suppressed the dye-coupling between acinar cells. The suppressive effects of adrenaline were weaker than those of ACh. Antagonists inhibited the above effect of agonists. Electrical coupling between acinar cells decreased 2 weeks after parasympathectomy, but sympathectomy did not affect it. These results suggest that parasympathetic nerve activity is related to the regulation and maintenance of the intercellular communication of acinar cells in the rat submandibular gland.

Acetylcholine↗
PubMed1988

12-O-tetradecanoylphorbol-13-acetate disrupts actin filaments and focal contacts and enhances binding of fibronectin-coated latex beads to 3T3-L1 cells.

The effect of a tumor-promoting phorbol ester on the binding of fibronectin-coated beads to 3T3-L1 cells was studied to clarify the relationship between the binding of fibronectin to the cells, cell adhesion, and the organization of actin filaments. Interference-reflection microscopy revealed focal contacts of 3T3-L1 cells with the substratum. Stress fibers observed after rhodamine-phalloidin staining were well-developed in the cells. Treatment of the cells for 20 min with 12-O-tetradecanoylphorbol-13-acetate (TPA), but not with phorbol, disrupted focal contacts and caused a reorganization of stress fibers to generate actin ribbons. Treatment of the cells with TPA enhanced the binding of beads coated with human plasma fibronectin to the cells, as observed after incubation for 6 h with the beads. The TPA-induced increase in the percentage of cells with bound beads was dependent on the duration of treatment with TPA and on the concentration of TPA. Treatment of the cells with TPA also enhanced proliferation of cells in a dose-dependent manner. The enhancement of binding of the beads by TPA was suppressed by addition of an adhesion-inhibitory peptide (Gly-Arg-Gly-Asp-Ser-Pro). Treatment with TPA did not enhance nonspecific binding of beads coated with heat-denatured bovine serum albumin. Furthermore, treatment of the cells with phorbol did not enhance the binding of beads coated with fibronectin. These results suggest that TPA specifically enhances the binding of fibronectin-coated beads to 3T3-L1 cells, and that TPA-induced binding of the beads may be related to disruption of focal contacts and reorganization of actin filaments.

Actin Cytoskeleton↗
PubMed1988

Suppression of intercellular communication in acinar cells from rat submandibular gland by cholinergic and adrenergic agonists.

The effects of cholinergic and adrenergic agonists on intercellular communication in isolated acini of rat submandibular gland were evaluated using dye-coupling. Cells injected with Lucifer Yellow CH showed diffusion of the dye to their coupled neighbors under the control condition. Addition of acetylcholine (ACh) and carbachol (CCh) at concentrations higher than 10(-6) M rapidly and reversibly suppressed the dye-coupling. This effect by 10(-4) M ACh or 10(-4) M CCh was blocked by the addition of 10(-6) M atropine. The suppressive effects of 10(-4) M adrenaline and 10(-4) M noradrenaline were weaker than those of 10(-4) M ACh. Treatment with 10(-4) M isoproterenol did not inhibit the dye-coupling and the suppressive effect by 10(-4) M adrenaline was blocked by the addition of 10(-5) M phenoxybenzamine. The inhibition of dye-coupling by ACh and adrenaline was blocked by the addition of 10(-5) M verapamil, 10(-4) M W-7 and 1.5 x 10(-5) M H-7, but not by 1.5 x 10(-5) M HA1004. These results suggest that the muscarinic action of cholinergic agonists and the alpha-action of adrenergic agonists might suppress the intercellular communication of the acinar cells in the rat submandibular gland, possibly through the increase of calcium influx and the activation of protein kinase C.

Acetylcholine↗
PubMed1988

[Clinical comparison of 99mTc-diethylenetriaminepentaacetic acid-human serum albumin (99mTc-HSA-D) and 99mTc-human serum albumin (99mTc-HSA) for cardiac blood pool imaging].

99mTc-HSA-D has been developed as a new blood pool scanning agent. Clinical comparison of 99mTc-HSA-D and 99mTc-HSA was made in 16 cases. The activity concentration of 99mTc in blood was measured during 2 hours after the injection in five cases. 99mTc-HSA-D showed higher concentration compared to 99mTc-HSA with the passage of time. Quantitative analysis of contrast between left ventricle and septum was performed on end diastolic frames of gated images 10 minutes after the injection. There was no obvious difference between 99mTc-HSA-D and 99mTc-HSA. The subjective comparison of detectability of lesions between the two agents was performed on three directional gated images. 99mTc-HSA-D was superior to 99mTc-HSA, because the images of the latter deteriorated with the passage of time. On anterior view images 1 hour after the injection, left ventricle/lung and abdominal aorta/background count ratios were greater for 99mTc-HSA-D in many cases. There was no obvious difference in liver/background and kidney/background count ratios between the two agents. Urinary excretion of 99mTc was considerably lesser for 99mTc-HSA-D. The results indicated that 99mTc-HSA-D was superior to 99mTc-HSA for cardiac blood pool imaging.

Aged↗
PubMed1987

Possible involvement of reorganization of actin filaments, induced by tumor-promoting phorbol esters, in changes in colony shape and enhancement of proliferation of cultured epithelial cells.

Tumor promoters are known to induce reorganization of actin, morphological changes and enhancement of proliferation of epidermal cells in vivo. In this study, we have examined the effects of tumor promoters on these events to clarify the role played by the organization of actin filaments in the regulation of the shape and growth of colonies of epithelial cells in culture. Treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA) caused a change in the shape of colonies of FL and Madin-Darby canine kidney (MDCK) cells within 6 hr. Changes in the shape of colonies were consistent with the morphological change of individual cells and the dissociation of groups of cells in the colonies. Addition of TPA also caused reorganization of actin filaments after 2 hr, and it caused enhancement of proliferation of FL and MDCK cells after 48 hr but did not cause any such changes in KB cells. However, the binding affinities of 4 beta-phorbol 12,13-dibutyrate (PDBu) to FL and MDCK cells were similar to that of PDBu to KB cells. Related tumor promoters such as phorbol 12,13 didecanoate (PDD) and mezerein caused effects similar to those caused by TPA. In contrast, nontumor promoting phorbol esters, such as 4 alpha-PDD and phorbol, had no effect. Cyclic AMP blocked the TPA-induced changes in FL and MDCK cells. These results suggest that TPA-induced reorganization of actin filaments which can be inhibited by cyclic AMP results in changes in the shape of colonies and enhancement of proliferation.

Actins↗
PubMed1987

Effects of denervation on cell-to-cell communication between acinar cells of rat submandibular salivary gland.

Communication measured by electrical cell coupling and dye transfer decreased transiently 1 day after parasympathectomy and then recovered 2 days later. Parasympathectomy decreased communication again 2 weeks later, coinciding with a decrease in the wet weight of the gland, but sympathectomy did not affect it. Thus parasympathetic nerve activity may be required for the regulation and maintenance of cell-to-cell communication in the rat submandibular gland.

Animals↗
PubMed1987

Intercellular contacts and the organization of actin filaments in cultured epithelial FL cells are altered by growth on type I collagen and treatment with 12-O-tetradecanoylphorbol-13-acetate through the modulation of interactions between cells and the substratum.

We have investigated the effects of various types of collagen and a tumor-promoting phorbol ester on intercellular contacts and the organization of actin in human amnion epithelial FL cells and mouse fibroblast 3T3-A31 cells. Our purpose was to investigate how modulation of interactions between cells and the substratum leads to alterations in intercellular contacts and organization of actin filaments. When cells were cultured on dishes coated with a solution containing type I collagen, but not type IV, changes were induced in the morphology of FL cells and their intercellular contacts. Type I collagen also caused changes in the organization of their actin filaments, although no such effects were observed with 3T3-A31 cells. In contrast, 12-O-tetradecanoylphorbol-13-acetate (TPA) caused morphological changes, dissociation of groups of cells, and reorganization of actin filaments in cultures of FL and 3T3-A31 cells. It also disrupted the sites of adhesion of FL cells to the substratum. Both type I collagen and TPA rapidly induced spreading of FL cells in the absence of serum. However, cis-hydroxyproline, known to inhibit secretion of collagen, did not suppress the TPA-induced dissociation of groups of FL cells. These results suggest that the interactions with type I collagen of epithelial FL cells, but not of fibroblastic 3T3-A31 cells, tend to disorganize cellular morphology, intercellular contacts, and actin filaments in ways similar to, but not directly related to, the effects of TPA.

Actins↗
PubMed1987

Suppression by herbimycin A of 12-O-tetradecanoylphorbol-13-acetate-induced dissociation of cells and morphological changes in cultured FL and MDCK cells.

Human amnion membrane epithelial (FL) and Madin-Darby canine kidney (MDCK) cells formed colonies which consisted of tightly packed cells. A bundle of actin filaments in the cells at the edge of the colonies ran parallel to the outline of these cells. The cells were attached to the substratum by regions which were observed as black solid lines by interference-reflection microscopy. Treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA) for 24 hr induced dissociation of and morphological changes in the cells in the colonies. TPA also disrupted the organization of the actin filaments and the attachment of cells to the substratum. Addition of herbimycin A for 24 hr inhibited the TPA-induced dissociation of the cells in colonies. Treatment with herbimycin A also inhibited TPA-induced modulation of the organization of actin filaments and of the adhesion of cells to the substratum. However, herbimycin A did not inhibit the rapid spreading of cells induced by TPA in the absence of serum. These results suggest that herbimycin A inhibits the dissociation of cells and the morphological changes induced by TPA through suppression of the disruption of a bundle of actin filaments and modulation of adhesion of cells to the substratum.

Actins↗