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Biomedical subjects

T Taniguchi

Publications and source records attributed to T Taniguchi.

At least 361 records · Page 20Linked to original sources
PubMed1996

Effects of endothelin A and B receptors on aqueous humor dynamics in the rabbit eye.

This study attempted to clarify the role of endothelin A and B (ETA and ETB) receptors in modulating aqueous humor dynamics in the rabbit eye. Intraocular pressure (IOP), aqueous flow, total outflow facility, and uveoscleral outflow were measured before, and 24 hours after, intravitreal injection (20 microliters) of a selective ETB agonist, sarafotoxin S6c (SRTX S6c, 10(-5) M), into one eye and its vehicle into the contralateral eye. The measurements were also performed before and after injection of a selective ETA antagonist, 97-139 (10(-2) M) + ET-1 (10(-5) M) into one eye, and vehicle + ET-1 (10(-5) M) into the contralateral eye. In the SRTX S6c-treated eye, total outflow facility increased significantly by 106% compared with that in the vehicle-treated eye 24 hours after injection; aqueous flow and uveoscleral outflow failed to change significantly. The ETA antagonist 97-139 inhibited the decrease in aqueous flow partially, but significantly, but failed to inhibit the increase in total outflow facility caused by ET-1. Therefore, both ETA and ETB play a significant role in modulating aqueous humor dynamics in the rabbit eye. ETA can modulate aqueous humor production, at least in part. ETB can modulate total outflow facility, and the possibility for ETB in modulating aqueous humor formation cannot be ruled out.

Animals↗
PubMed1996

Ocular hypotensive mechanism of topical isopropyl unoprostone, a novel prostaglandin metabolite-related drug, in rabbits.

This study was performed to clarify the ocular hypotensive mechanism of topical isopropyl unoprostone (unoprostone), a novel prostaglandin (PG) metabolite-related drug, in the rabbit eye. The intraperitoneal administration of indomethacin (50 mg/kg) 1 hour before administration of topical 0.12% unoprostone partially diminished the intraocular pressure (IOP) reduction, and completely blocked the increase in aqueous PGE2 concentration caused by unoprostone. Aqueous humor dynamics measurements in the unoprostone- and the vehicle-treated contralateral eyes with indomethacin pretreatment revealed that aqueous flow determined by fluorophotometry was not significantly different, 2.3 +/- 0.3 and 2.4 +/- 0.2 microliters/min, respectively; the total outflow facility measurements determined by the two-level constant pressure perfusion method were 0.20 +/- 0.01 and 0.14 +/- 0.01 microliters/min/mmHg, respectively (p < 0.05); the uveoscleral outflow measurements determined by the fluorescein isothiocyanate-dextran perfusion method were 0.49 +/- 0.02 and 0.46 +/- 0.02 microliters/min, respectively (p < 0.05). The magnitude of the IOP reduction induced by unoprostone was estimated to be 5.2 mmHg, which agrees well with the actual IOP reduction. In conclusion, unoprostone lowers the IOP by affecting aqueous outflow pathways, primarily the pressure-dependent conventional pathway and the secondary uveoscleral outflow pathway in rabbits. Endogenous PGs induced by topical unoprostone are also involved in lowering the IOP in rabbits.

Administration, Topical↗
PubMed1996

Lidocaine attenuates the hypotensive and inflammatory responses to endotoxemia in rabbits.

OBJECTIVE: To assess the effects of lidocaine on the hemodynamic and inflammatory responses to Escherichia coli endotoxemia in rabbits. DESIGN: Prospective, randomized, controlled experimental study. SETTING: University laboratory. SUBJECTS: Twenty-seven female Japanese rabbits, anesthetized with urethane and ventilated mechanically. INTERVENTIONS: Animals were randomly assigned to one of three groups: a) endotoxemic control group (n = 9), receiving intravenous Escherichia coli endotoxin (0.5 mg/kg bolus) via the mesenteric vein; b) laparotomy control group (n = 9), treated identically to the endotoxemic control group, except for substitution of 0.9% saline for endotoxin; and c) lidocaine-treated group (n = 9), treated identically to the endotoxemic controls and additionally, intravenous lidocaine (3 mg/kg bolus, followed by infusion at 2 mg/kg/hr) was administered immediately after endotoxin MEASUREMENTS AND MAIN RESULTS: We compared hemodynamics, blood gases, and microscopic findings of lung tissue obtained at necropsy in each group. Laparotomy alone had a minimal effect on the parameters and findings. Endotoxin injection decreased mean systolic arterial pressure from 135 +/- 6 (SD) to 95 +/- 25 mm Hg (p < .05) and increased the mean base deficit from -1.2 +/- 1.8 to -14.4 +/- 4.2 mmol/L (p < .05), and caused the infiltration of neutrophils into the lungs. Lidocaine administration abolished the hypotension and attenuated the increase the base deficit to -9.5 +/- 2.1 mmol/L (p < .05) and the cellular infiltration in comparison with endotoxemic controls. CONCLUSIONS: Lidocaine attenuated the hemodynamic and inflammatory responses to endotoxemia in rabbits. Findings suggest that lidocaine administration may prevent the development of hypotension and metabolic acidosis during endotoxemia.

Acid-Base Equilibrium↗
PubMed1996

Antiproliferative effect of a novel cholecystokinin-B/gastrin receptor antagonist, YM022.

Cholecystokinin (CCK)-B and gastrin receptors are expressed on a variety of human tumor cells. Recently, we have demonstrated that the human brain CCK-B receptors are identical to the gastrin receptors derived from the stomach mucosa, and that the brain-gut peptides, CCK-8 and gastrin I are mitogenic for mouse NIH 3T3 fibroblasts expressing human CCK-B/gastrin receptors (N-hCCKBR). In this report, we evaluated the antiproliferative potency of CCK-B/gastrin receptor antagonists by using N-hCCKBR cells. Among several antagonists, a benzodiazepine derivative, YM022 had the most potent activities in competing with [125I]CCK-8 or [125I]gastrin I binding, inhibition of CCK-8- or gastrin I-induced phosphoinositide hydrolysis and increasing cytoplasmic free calcium. Interestingly, a potent antagonist for rat CCK-B/gastrin receptors did not have such activities in N-hCCKBR cells. YM022 inhibited the CCK-8- or gastrin I-induced [methyl-3H]thymidine incorporation of N-hCCKBR cells in a dose-dependent manner. In the absence of exogenous peptide ligands, YM022 also inhibited the proliferation of several human cancer cell lines expressing the genes for both gastrin and its receptor. These results suggest that YM022 could intervene in the autocrine stimulation of human tumor cell lines through CCK-B/gastrin receptors. N-hCCKBR cells are an excellent tool to screen for novel human CCK-B/gastrin receptor antagonists possessing antiproliferative activity for human cancer cells.

3T3 Cells↗
PubMed1996

A novel interferon regulatory factor family transcription factor, ICSAT/Pip/LSIRF, that negatively regulates the activity of interferon-regulated genes.

We have isolated a novel cDNA clone encoding interferon (IFN) consensus sequence-binding protein in adult T-cell leukemia cell line or activated T cells (ICSAT); this protein is the human homolog of the recently cloned Pip/LSIRF. ICSAT is structurally most closely related to the previously cloned ICSBP, a member of the IFN regulatory factor (IRF) family of proteins that binds to interferon consensus sequences (ICSs) found in many promoters of the IFN-regulated genes. Among T-cell lines investigated, ICSAT was abundantly expressed in human T-cell leukemia virus type 1 (HTLV-1)-infected T cells. When the HTLV-1 tax gene was expressed or phorbol myristake acetate-A23187 stimulation was used, ICSAT expression was induced in Jurkat cells which otherwise do not express ICSAT. When the binding of ICSAT to four different ICSs was tested, the relative differences in binding affinities for those ICSs were determined. To study the functional role of ICSAT, we performed cotransfection experiments with the human embryonal carcinoma cell line N-Tera2. ICSAT was demonstrated to possess repressive function over the gene activation induced by IFN stimulation or by IRF-1 cotransfection. Such repressive function is similar to that seen in IRF-2 or ICSBP. However, we have found that ICSAT has a different repressive effect from that of IRF-2 or ICSBP in some IFN-responsive reporter constructs. These results suggest that a novel mechanism of gene regulation by "differential repression" is used by multiple members of repressor proteins with different repressive effects on the IFN-responsive genes.

Amino Acid Sequence↗
PubMed1996

Assessment of protein kinase C mRNA levels in Alzheimer's disease brains.

We have previously demonstrated that the protein level of type beta protein kinase C (PKC) was significantly reduced in Alzheimer's disease (AD) brains compared to controls. To clarify whether this is due to decreased synthesis and/or increased degradation of PKC, the present study was performed to examine mRNA levels of PKC isozymes in control and AD brains. The present study indicated that mRNA levels of types alpha, beta and gamma PKC were not significantly changed in the control and AD brains. Thus, the reduction of type beta PKC protein content in AD brains might be caused by increased degradation.

Aged↗
PubMed1996

Influence of oocyte aging on developmental ability of reconstituted embryos produced from oocyte cytoplast and single blastomeres of two-cell stage embryos.

The present study was conducted to investigate the influence of aging of recipient oocyte on the developmental ability of reconstituted mouse embryos produced from the cytoplast of oocytes and single blastomeres of early or late 2-cell stage embryos by electrofusion. Oocytes were obtained at 14 (newly ovulated oocytes), 18, 22 (oocyte that time passed after ovulation; aged oocyte) hr after hCG injection and oocyte cytoplast was produced by manual enucleation using a fine glass needle under the dissecting microscope. The aging of the oocytes significantly influenced on the fusion rate of the reconstituted embryos (14 hr: 42.7-47.2% vs. 22 hr: 75.3-77.6%). Similarly, the cleavage rate of reconstituted embryos increased with aging of the oocytes (14 hr: 50.8-56.3% vs. 22 hr: 82.2-90.7%). The percentage of reconstituted embryos produced from cytoplast of aged oocytes (22 hr post hCG) and single blastomeres of late 2-cell stage embryos developing to the blastocyst (20.8%) was significantly higher than that of reconstituted embryos produced by other combinations (2.0-8.2%: P < 0.01). Although cell cycle stage of donor nuclei influenced to developmental ability of reconstituted embryos, these results are probably related to the aging of the oocytes since aged oocytes can be activated more easily by electrical stimulation than newly ovulated oocytes.

Animals↗
PubMed1996

The effects of intravitreally injected endothelin-1 on the iris-ciliary body microvasculature in rabbits.

PURPOSE: We previously reported that intravitreal injection of 0.5 microg of endothelin-1 (ET-1) caused both a sustained reduction of intraocular pressure (IOP) and decreased aqueous production in the rabbit eye. On the theory that these effects might have resulted from a sustained reduction of blood flow to the ciliary body due to ET-1-mediated vasoconstriction, in the present study we attempted to determine if ET-1 causes any changes in the vascular caliber of the iris-ciliary body. METHODS: ET-1 solution (0.5 microg) was injected into the vitreous of one eye of each of 10 albino rabbits; the same amount of vehicle was injected into the contralateral eyes. One h following these injections in five of the rabbits and 24 h following them in the other five rabbits, ocular microvascular castings were obtained under controlled physiologic conditions, and the amount of vasoconstriction of the arterioles branching from the major arterial circle of the iris (MAC) and supplying the iris-ciliary body was measured by a scanning electron microscope and expressed as a percentage. RESULTS: The ET-1 caused a statistically significant focal vasoconstriction in the treated eyes as compared with the contralateral, control eyes (9.9% at 1 h and 6.2% at 24 h; both P = . 0001). CONCLUSIONS: Intravitreally injected ET-1 caused statistically significant, but only mild vasoconstriction of the arterioles supplying the ciliary processes.

Animals↗
PubMed1996

[Effects of amosulalol hydrochloride on intraocular pressure and aqueous humor dynamics in the rabbit eye].

The effects of amosulalol, which blocks alpha 1 adrenoceptors selectively and beta receptors nonselectively almost to the same extent, on intraocular pressure (IOP) and aqueous humor dynamics were studied in pigmented rabbits. Administration of topical amosulalol (0.5%) resulted in a significant difference in IOP between the treated and the contralateral eyes from 0.5 to 6 hours, and the maximum IOP reduction, 6.0 +/- 0.4 mmHg (mean +/- standard error), was observed at 2 hours after administration. Aqueous humor dynamics measurements (mean +/- standard error) in the amosulalol (0.5%)-treated and the contralateral eyes revealed that total outflow facility determined by the two-level constant pressure perfusion method was not significantly different, 0.14 +/- 0.01 and 0.12 +/- 0.01 microliter/min/mmHg, respectively; the aqueous flow measurements determined by fluorophotometry were 3.0 +/- 0.1 and 3.4 +/- 0.2 microliters/min, respectively (p < 0.05, -11%); the uveoscleral outflow measurements determined by the fluorescein isothiocyanate-dextran perfusion method were 0.53 +/- 0.04 and 0.46 +/- 0.04 microliter/min, respectively (p < 0.05, +15%). In conclusion, amosulalol lowers the IOP by inhibiting aqueous production and increasing uveoscleral outflow.

Adrenergic alpha-Antagonists↗
PubMed1996

Regulation of endothelial growth factor expressions in breast cancer.

Expression of various endothelial growth factors including vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), Platelet-derived endothelial cell growth factor (PD-ECGF) and hepatocyte growth factor (HGF) was investigated in human breast carcinoma tissues, and the results were compared to the intratumoral microvessel density evaluated by the immunostaining to anti-factor VIII related antigen. VEGF and PD-ECGF were examined by immunostainings, and bFGF and HGF were assessed by enzymatic immunoassays. As a result, VEGF and PD-ECGF were significantly associated with the increment of microvessel density, although no significant correlation was found with bFGF and HGF. In addition, interestingly, a tendency of co-expression between VEGF and PD-ECGF was demonstrated. It was suggested that VEGF and PD-ECGF play important roles in the promotion of angiogenesis in human breast cancer.

Breast Neoplasms↗
PubMed1996

[Effects of prostaglandin E1 on plasma cytokine levels during pneumonectomy].

We investigated the effect of prostaglandin E1 (PGE1) on intraoperative cytokine responses and the incidence of postoperative complications. Twenty-six patients undergoing elective pneumonectomy were randomly allocated into PGE1 group (n = 12) and control group (n = 14). The PGE1 group received continuous infusion of PGE1 during surgery at a dose of 0.02-0.03 microgram.kg-1.min-1. Blood samples were obtained after induction of general anesthesia, one and two hours after incision, and immediately after the end of surgery to measure the plasma levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and interleukin-8 (IL-8). Levels of CRP for two days after the surgery were measured and postoperative complications were recorded. Levels of TNF-alpha rose from 1.6 pg.ml-1 (mean) to 4.8 pg.ml-1 two hr after incision in the control group, while the level was suppressed in the PGE1 group (P < 0.05). No significant difference was found in IL-6 levels between the two groups. The IL-8 increased during surgery in both groups but the increase was significantly less in the PGE1 group (P < 0.05). There was no difference in CRP, and no severe postoperative complication was observed. We conclude that PGE1 administration suppresses TNF-alpha and IL-8 responses during pneumonectomy, but its effects on IL-6 and the postoperative status were not significant.

Aged↗
PubMed1996

Effects of BQ-123, an ETA recepter-selective antagonist, on changes of intraocular pressure, blood-aqueous barrier and aqueous prostaglandin concentrations caused by endothelin-1 in rabbit.

Endothelin-1 (ET-1) is known to affect the intraocular pressure (IOP) in rabbits. We reported that intravitreally administered ET-1 induced biphasic IOP response, an early transient IOP rise followed by a subsequent prolonged decrease. In an attempt to clarify the role of ET receptor subtypes in the IOP responses following ET-1 injection, we studied the effects of ETA receptor-specific antagonist, BQ-123, in rabbits. We also evaluated the possible role of prostaglandins (PGs) and the disruption of the blood-aqueous barrier (BAB) following ET-1 injection in modulating the IOP change. BQ-123 (126.5 or 12.6 micrograms) was injected into the vitreous (20 microL/eye) of one eye in a group of 5 rabbits. Contralateral eyes received the same amount of vehicle in a masked randomized fashion. The same amount of ET-1 (0.5 or 0.05 micrograms) was injected intravitreally 30 minutes later into both eyes. IOP was measured prior to and periodically up to 120 hours after injection using a calibrated pneumatonometer. In another experiment BQ-123 (126.5 micrograms) was injected into one eye of 4 rabbits and the other eye served as a control to observe the effect of BQ-123 on the IOP. One hour and 24 hours following the injection of BQ-123 and ET-1, approximately 100 microL of aqueous humor was withdrawn by paracentesis. Protein concentration was measured by Lowry's method and PGE2 concentration, by radioimmunoassay. BQ-123 had no effect on the IOP when used alone. When used in combination with ET-1, BQ-123 (126.5 micrograms) significantly inhibited both the IOP rise (0.5-1 hour) and the reduction (24-72 hours) caused by ET-1 (0.5 microgram). BQ-123 (12.6 micrograms) also significantly inhibited the IOP reduction (6-8 hours and 72-96 hours) caused by ET-1 (0.05 micrograms). Pre-injection of BQ-123 (126.5 micrograms) significantly suppressed the increase in the aqueous protein and the PGE2 concentration both at 1 and 24 hours. The IOP response and the elevation of aqueous protein and PGE2 concentration following ET-1 injection are at least partly mediated by ETA receptors.

Animals↗
PubMed1996

[Three cases of tuberculous mediastinal lymphadenitis].

Mediastinal lymph node involvement is uncommon in intrathoracic tuberculosis. We report three cases of this disease, each of which had a different clinical course. Chest CT scans showed preferential involvement of right paratracheal nodes, central areas of relatively low density with peripheral rim enhancement after injection of contrast medium. Specimens obtained by mediastinoscopy and fiberoptic bronchoscopy revealed acid-fast bacilli in all cases. In view of its relative frequency, tuberculous mediastinal lymphadenitis in adults must be distinguished from other causes of mediastinal masses.

Adult↗
PubMed1996

Epithelial barrier function of the filtering bleb conjunctiva and the cornea after trabeculectomy with mitomycin C.

PURPOSE: To evaluate epithelial barrier function of the filtering bleb conjunctiva and the cornea after trabeculectomy with adjunct, intraoperative mitomycin C, by using a newly developed slit-lamp fluorophotometer. SUBJECTS AND METHODS: Thirteen patients with normal-tension glaucoma with a cystic filtering bleb who had undergone unilateral trabeculectomy with mitomycin C only once at least 1 year previously were subjected to the study. Epithelial barrier function of the bleb conjunctiva and the cornea in the operated eye was evaluated using an Anterior Fluorometer FL-500 to measure the uptake of topically applied fluorescein. RESULTS: Fluorescein uptake (nanograms per milliliter, mean +/- standard error) by the bleb conjunctiva (1,857 +/- 380) was not significantly different from either the uptake by the superior bulbar conjunctiva in the operated eyes, located approximately 90 degrees C away from the filtering bleb (1,974 +/- 258), or the uptake by the conjunctiva in the intact eyes, located symmetrically against the bleb (1,913 +/- 248). The corneal uptake in the operated eye (56.1 +/- 10.2) was not significantly different from that in the intact eye (53.5 +/- 8.3). CONCLUSIONS: Epithelial barrier function of the cystic filtering bleb conjunctiva and the cornea long after trabeculectomy with mitomycin C was demonstrated to be almost identical to that of the control.

Aged↗
PubMed1996

ONO-1078 antagonizes diarrhea-causing changes in ion transport and smooth muscle contraction induced by peptidoleukotrienes in rat and human colon in vitro.

Leukotrienes play important roles in inflammatory bowel diseases. Previous studies have revealed the effects of peptidoleukotrienes on smooth muscle contraction and transmucosal ion transport, which may cause hyperactive bowel movement and the loss of electrolytes and water, i.e., diarrhea. The purpose of the present study was to evaluate the effects of the peptidoleukotrienes antagonist ONO-1078 and to assess its possible future clinical use. We examined the effects of ONO-1078 on peptidoleukotrienes-induced changes in electrolyte transport and muscle contraction in the rat colon, with the Ussing and Magnus techniques. Human biopsy specimens obtained at colonoscopy were also used for ion transport studies. Transmucosal ion transport in both rats and humans, and smooth muscle contractions in the rat colon, were induced by similar doses of peptidoleukotrienes at estimated interstitial concentrations (1 nM-100 nM). The time course of changes in short circuit current had two phases, a rapid and transient decrease and a subsequent transient increase, which seemed to be due mainly to Na+ and Cl-, respectively. Rat colon smooth muscle contracted transiently after the addition of peptidoleukotrienes. These effects of peptidoleukotrienes, which could be related to the diarrhea in inflammatory bowel diseases, were inhibited by ONO-1078. ONO-1078 is expected to be effective in clinical use against peptidoleukotrienes-related diarrhea in mild to moderate inflammatory bowel diseases.

Adult↗
PubMed1996

[Surgical treatment of pericostal tuberculosis].

The following two points must be considered on treating pericostal tuberculosis: the first is the appropriate time to treat pericostal tuberculosis surgically when the medical therapy fails to induce a remission, and the second is how to prevent postoperative relapse. In the present study, we investigated these two points by examining seven patients who underwent surgery at the department of thoracic surgery (Osaka Red Cross Hospital), during a 10 years period from January 1985 to December 1994. Antituberculotics were administered to these patients for an average of 3.9 months before surgery, but in vain. Therefore, they were surgically treated. In all cases, the incision was closed at once, and there were no severe complications. The signs and symptoms disappeared soon after surgery. It has been reported that the medical treatment leads to recovery or tendency to recovery within three months of drug administration. The conditions of pericostal tuberculosis patients during this period can be used as indicators to decide whether or not to carry out surgical treatment. Also, by active excision of the rib and tumor as one mass, and by administering antituberculotic for 13.1 months after surgery, no relapse took place during the follow-up period (average 37.4 months). And the postoperative respiratory functions did not decrease compared to those before surgery.

Adult↗
PubMed1996

Growth inhibition of K-ras-expressing tumours by a new vinca alkaloid, conophylline, in nude mice.

Conophylline, a new vinca alkaloid isolated from the plant Ervatamia microphylla induced normal flat morphology in K-ras-NRK and K-ras-NIH cell lines, and lowered the increased uptake of 2-deoxyglucose in K-ras-NRK cells. Conophylline inhibited the growth of K-ras-NRK cells, but this inhibition was reversible. The alkaloid also inhibited the growth of K-ras-NRK and K-ras-NIH3T3 tumours transplanted into nude mice. On the other hand, it showed no effect on survival of the mice loaded with L1210 leukaemia. Thus, conophylline is a new antitumour vinca alkaloid that induced normal phenotypes in ras-expressing cells.

Animals↗