PubMed Health⌕ Search

Biomedical subjects

Y Tanimoto

Publications and source records attributed to Y Tanimoto.

At least 37 records · Page 2Linked to original sources
PubMed1998

Angiographic follow-up of internal thoracic artery for free bypass grafting.

BACKGROUND: The use of free internal thoracic artery (ITA) grafts in patients with smaller body surface areas has been questioned because of technical difficulties and inadequate graft flow. METHODS: To evaluate postoperative changes in the diameter of free ITA grafts, we performed coronary angiography immediately after coronary artery bypass grafting and then again at a mean of 42 +/- 6 months later. In 20 consecutively treated patients, 21 free ITAs were used as bypass conduits. Two ITA grafts that were patent at the time of the first angiography had closed at the second angiography. Postoperative changes in ITA graft diameter were measured in the 19 patent ITA grafts. RESULTS: At the first angiography, the mean diameters of the proximal, middle, and distal ITA grafts were 2.28 +/- 0.45 mm, 2.34 +/- 0.39 mm, and 2.12 +/- 0.38 mm, respectively. At the second angiography, the mean diameters of the proximal, middle, and distal ITA grafts were 2.85 +/- 0.50 mm, 2.89 +/- 0.53 mm, and 2.72 +/- 0.53 mm, respectively. All segments of the ITA grafts had dilated significantly between the first and second angiographic evaluations (p < 0.01). The percentage change in graft diameter was greater when the initial ITA diameter was less than 2.3 mm (32.0% +/- 28.0%) than when it was 2.3 mm or more (18.8% +/- 11.3%) (p < 0.05). CONCLUSIONS: The postoperative increase in free ITA graft diameter depends on coronary blood flow requirements.

Adult↗
PubMed1998

Hepatic and splenic sarcoidosis evaluated by multiple imaging modalities.

We present a case of hepatosplenic sarcoidosis. A 51-year-old Japanese male, who was diagnosed to have sarcoidosis 4 years previously, was presented to our hospital because of dry cough and anorexia with weight loss. He had tender hepatosplenomegaly. A dynamic abdominal computed tomography (CT) revealed multiple small low-density areas in both liver and spleen, as well as in magnetic resonance imaging (MRI). The laparoscopic photographs showed many small whitish nodules surfacing on the liver and several tumorous nodules on the spleen. Multiple imaging modalities including dynamic CT and MRI are valuable for detecting focal hepatic and splenic lesions of sarcoidosis.

Biopsy↗
PubMed1998

A processed grain food inhibits hepatic injury in endotoxemic rats.

Although various antioxidants have been tested as therapeutics for endotoxemic subjects, the results of their efficacy are conflicting. Antioxidant biofactor (AOB) is a unique processed grain food that exhibits strong antioxidant activity (Minamiyama et al, J Nutr Sci Vitaminol, 40: 467-477, 1994). The present study was carried out to test the effect of AOB on hepatic injury in rats induced by lipopolysaccharide (LPS). Intravenous administration of LPS induced liver injury with a concomitant increase in hepatic generation of nitric oxide (NO) and 4-hydroxy-2-nonenal (HNE) modified proteins in the control group. The administration of AOB significantly inhibited the LPS-induced hepatic injury and generation of HNE-modified proteins and increased the survival rate of endotoxemic rats without affecting NO generation and plasma levels of tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma). AOB scavenged superoxide radicals without affecting NO production by LPS-stimulated macrophage cell line J 774.2 cells. AOB also inhibited lipid peroxidation induced by LPS in the cells. These results suggested that AOB might scavenge superoxide radicals and decrease toxic metabolites including HNE, thereby inhibiting liver injury in endotoxemic rats.

Alanine Transaminase↗
PubMed1997

Preincubation of thymocytes with 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H-7) induces apoptosis in non-stimulated thymocytes.

1-(5-Isoquinolinesulfonyl1)-2-methylpiperazine hydrochloride (H-7), an inhibitor of protein kinases, has been shown to inhibit the thymocyte apoptosis induced by various apoptogenic agents. In the present study, when mouse thymocytes were pretreated with H-7, washed, and cultured for an additional time, apoptosis was induced depending on the preincubation time and the dose of H-7. The protein kinase C activity in the H-7-pretreated and -washed cells was not altered, suggesting that an alteration of a certain PKC isoform is related to both the triggering and the progression of apoptosis.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1997

Peptidyl aldehyde inhibitors of proteasome induce apoptosis rapidly in mouse lymphoma RVC cells.

Proteases play an important role in regulation of apoptosis. To elucidate the role of proteasome in apoptosis, we examined the effects of the proteasome inhibitors, carbobenzoxy-L-isoleucyl-gamma-t-butyl-L-glutamyl-L-alanyl-L-leucinal and carbobenzoxy-L-leucyl-L-leucyl-L-norvalinal on RVC lymphoma cells. Cells exposed to the proteasome inhibitors arrested at G2/M phase followed by internucleosomal DNA cleavage, chromatin condensation, and formation of apoptotic bodies dose- and time-dependently. Ubiquitinated histone H2A levels decreased in the exposed cells, suggesting a relationship between deubiquitination of histone H2A and the chromatin disarray seen in apoptosis. Northern blots showed an increase in expression of polyubiquitin genes early in the incubation. These findings suggest that the ubiquitin-mediated proteasome-proteolytic system is involved in regulating the cell cycle and apoptosis in RVC cells.

Animals↗
PubMed1997

Irreversible inhibition of cytochrome P450 by nitric oxide.

Nitric oxide (NO) modulates various metabolisms through interaction with thiol proteins and hemoproteins. Although NO interacts reversibly with iron moieties of heme proteins, including cytochrome P450 (P450), dynamic aspects of the formation, catalytic functions and fates of NO-P450 adducts remain to be elucidated. When incubated with NOC7, which spontaneously and stoichiometrically releases NO within 5 min, microsomal P450 rapidly formed nitrosyl-heme adducts as determined by the electron spin resonance method. The signal intensity for the complex increased with time, peaking at 30 min and decreasing to below detectable levels by 60 min of incubation. In contrast, the microsomal levels of low-spin ferric forms of P450 (g = 2.26) rapidly decreased during the initial 30 min but recovered time-dependently thereafter. Analysis by differential spectra (reduced form/CO-reduced form) revealed that on incubation with NOC7, the form of microsomal P450 also changed in a biphasic manner. To elucidate the mechanism for the decrease in the levels of P450, microsomal levels of P450 isozymes (CYPs) were determined by Western blot analysis using specific antibodies against CYP3A2 and CYP2C11, major isoforms found in male rat liver. Kinetic analysis revealed that no appreciable degradation of P450 proteins occurred during the incubation of microsomes with NOC7. The effect of NO on the catalytic activity of the enzymes was determined by using testosterone as substrate because hydroxylation of steroid hormones is one of the major functions of P450. When exposed to NO, the hydroxylation activity in microsomes rapidly decreased during the initial 10 min and then disappeared slowly. These results suggested that NO formed dissociable complexes with P450 isozymes and the catalytic functions of these isozymes were irreversibly inactivated after dissociation from their heme moiety.

Animals↗
PubMed1997

Inflammation and apoptosis.

Apoptosis is a highly regulated form of programmed cell death defined by distinct morphological and biochemical features; it plays an important role in embryogenesis and the maintenance of cellular and tissue homeostasis in multicellular organisms. Its perturbation has been implicated in a wide range of patho-physiological stages, including autoimmune, bacterial, and viral disease, and degenerative disorders. The critical role of apoptosis in eliminating harmful or injured cells from tissues suggests its participation in inflammatory processes and in the resolution of inflammatory reactions. In this article, we briefly review the molecular mechanism of apoptosis and the role of apoptosis in inflammation.

Animals↗
PubMed1996

Permeability of dormant spores of Bacillus subtilis to gramicidin S.

Gramicidin S, dissolved in ethanol, penetrated into the inside of the dormant spores of Bacillus subtilis, had a partial inhibitory effect on L-alanine-initiated germination and completely inhibited their outgrowth and vegetative growth. The activity of particulate NADH oxidase of the antibiotic-treated dormant spores was also influenced significantly. Abnormal morphological changes were observed in germinated spores from gramicidin S-treated dormant spores. An immunoelectron microscopy method with colloidal gold-IgG complex showed that the penetration site of gramicidin S inside dormant spores was mainly the core region. These facts suggest that gramicidin S induces the damage of not only the outer membrane-spore coat complex but also the inner membrane surrounding the spore protoplast, and is able to penetrate into the core region of B. subtilis dormant spores.

Alanine↗
PubMed1996

Signal transduction by IgG receptors induces calcium mobilization, but not histamine release, in the human basophilic cell line KU812F.

Human blood basophils selectively express Fc gamma RII (CDw32) among IgG receptor subtypes, but its functional role in allergic reactions remains unknown. Using the human basophilic leukemia cell line KU812F as a model system, we investigated cellular signaling events mediated through IgG receptor stimulation. KU812F cells express Fc gamma RII on their surface. mRNAs for both Fc gamma RIIA and IIB subtypes were detected by reverse transcriptase-PCR analysis. In this cell line, Fc gamma RII stimulation induced mobilization of free intracellular calcium and actin polymerization. Yet, no significant histamine release was observed, nor did blood basophils stimulated by anti-Fc gamma RII monoclonal antibody IV.3 and by a secondary antibody release histamine. These data indicate that Fc gamma RII stimulation induces cellular signaling events such as calcium mobilization in human basophils. However, these events do not lead to histamine release.

Actins↗
PubMed1996

[Coronary artery bypass grafting surgery without cardiopulmonary bypass in a patient with calcified aorta].

Coronary artery bypass surgery in a 67-year-old male with severe calcified ascending aorta was performed without cardiopulmonary bypass under beating heart, utilizing the left internal thoracic artery graft. No neurological complication was observed and postoperative angiogram showed good graft patency. We think coronary revascularization without cardiopulmonary bypass can be one of the safe and reliable methods to avoid complications associated with aortic cross clamping and aortic cannulation with severely calcified aorta.

Aged↗
PubMed1995

Biological responses in Caenorhabditis elegans to high magnetic fields.

Here we describe a device for testing possible influences of high magnetic fields on biological processes, by which alternating-current magnetic stimuli as high as 1.7 T can be administered. Experiments with a simple multicellular organism, the nematode Caenorhabditis elegans, revealed that intermittent exposure to the magnetic fields modestly inhibited the animal's reproduction as well as its post-embryonic development, and caused a marked but transient derangement in its locomotory behavior. Available evidence indicates that alternating high magnetic fields can elicit both chronic and acute biological effects, but that the effects may be well tolerated or compensated for by the living organism.

Animals↗
PubMed1995

Photochemistry of acetylenic ketones in micellar solutions as studied by product-yield-detected ESR and transient absorption techniques.

The electron spin resonance (ESR) spectra of the transient radical pairs in the photoreduction of 1,5-diphenyl-1,4-pentadiyn-3-one(I) and 1,3-diphenyl-2-propyn-1-one(II) in sodium dodecyl sulfate (SDS) micellar solutions have been obtained by using the product-yield-detected ESR (PYESR) technique. The PYESR spectra, detected by tracing the microwave effect on the spin-adduct yield as functions of the magnetic field, show the ESR spectra of the ketyl radical of the ketone and SDS radical as the components of the radical pairs. In addition, the growth and the decay processes of the radical pair were observed through detecting the effect of microwave pulse as functions of the delay period between a laser pulse and the off and on time, respectively, of a microwave pulse. The absorption spectra of transient species have also been obtained by using the laser flash photolysis technique. Through the analysis of these data and molecular orbital calculations, the role of acetylenic groups in the photoreactivity of acetylenic ketones is discussed.

Alkynes↗
PubMed1995

Studies on agents with vasodilator and beta-blocking activities. II.

A series of phenoxypropanolamines having a hydrazinopyridazinyl moiety was synthesized. Their hypotensive and beta-blocking activities were evaluated after intravenous administration of the compounds to anesthetized rats. Some of them exhibited both activities. In particular, compound 20k is a candidate for clinical use due to its hypotensive activity, equal to that of hydralazine, and its beta-blocking activity, 2.7-fold more potent than that of propranolol.

Adrenergic beta-Antagonists↗
PubMed1995

[Vein patch angioplasty for coronary revascularization to ischemic heart disease: report of two cases].

Two cases of vein patch angioplasty for ischemic heart disease were presented. The first case (59-year-old female) admitted to our hospital because of posterolateral infarction. Preoperative coronary angiogram (CAG) showed stenosis of 4-PD of RCA, proximal LAD and distal LCX. The second case (62-year-old male) admitted for operation of abdominal aortic aneurysm. Preoperative CAG showed stenosis of proximal RCA and mid LAD. Stenosis of 4-PD and proximal RCA was relieved by patch angioplasty using saphenous vein graft and coronary artery bypass to LAD was performed by left internal thoracic artery graft. Both cases showed successful enlargement of RCA stenosis and good graft patency at the postoperative CAG. Vein patch angioplasty is thought to be an alternative method for coronary revascularization to ischemic heart disease.

Female↗
PubMed1995

[Interferon production in peripheral blood cells of patients with pulmonary mycobacterial disease].

Production of interferon (IFN)-alpha and IFN-gamma were examined in 31 patients with acute tuberculosis, 12 patients with atypical mycobacterial disease. IFN production was examined in cultures of unseparated fresh whole blood. Production of IFN-alpha was induced by hemagglutinating virus of Japan and production of IFN-gamma was induced by PHA. Patients with mycobacterial disease produced significantly less IFN-alpha than healthy subjects. In patients with acute tuberculosis, effective chemotherapy for 2 months restored IFN-alpha production. Patients produced less IFN-gamma than healthy subjects, but the difference was not significant. Patients with high serum CRP levels tended to produce little IFN-alpha. These results suggest that measurement of IFN production is useful for immunological evaluation of patients with mycobacterial disease.

Acute Disease↗
PubMed1995

Staurosporine-induced thymocyte apoptosis is inhibited by herbimycin A, a specific inhibitor of protein tyrosine kinase.

When mouse thymocytes were incubated with staurosporine at low doses (1-100 nM), increased tyrosine phosphorylation of proteins with a molecular weight of 31-34 kD in the detergent-soluble fraction was observed, together with an increase in internucleosomal DNA fragmentation. Incubation with staurosporine for 6 h was enough to trigger and progress of apoptosis. Herbimycin A, a specific inhibitor of protein tyrosine kinases, and cycloheximide, an inhibitor of protein synthesis, reduced the amount of the phosphotyrosine proteins, this being followed by the inhibition of DNA fragmentation and cell death, suggesting a close relationship between protein tyrosine phosphorylation and the induction of apoptosis by staurosporine.

Alkaloids↗