Biomedical subjects

Y Yano

Publications and source records attributed to Y Yano.

At least 217 records · Page 12Linked to original sources

PubMed1994

Suppressive effects of the extracts of Japanese edible seaweeds on mutagen-induced umu C gene expression in Salmonella typhimurium (TA 1535/pSK 1002) and tumor promotor-dependent ornithine decarboxylase induction in BALB/c 3T3 fibroblast cells.

Some of epidemiological data indicated that ubiquitous consumption of seaweeds in Japan may be a possible protective factor against some types of tumor. To analyse this problem, the authors studied the antimutagenic and antitumor promotion activities in methanol-soluble extracts of typical edible seaweeds which showed suppressive effects on 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indol (Trp-P-1)-induced umu C gene expression in SOS response of Salmonella typhimurium (TA 1535/pSK 1002) and 12-O-tetradecanoylphorbol-13-acetate (TPA)-dependent ornithine decarboxylase induction in BALB/c 3T3 fibroblast cells. Although eight varieties of edible seaweeds including chlorophyta, Phaenophyta and Rhodophyta showed significant antimutagenic and antipromotion activities, they expressed the activities different from each other. Among these seaweeds, Enteromorpha prolifera ('Sujiaonori' in Japanese) and Porphyra tenera ('Asakusanori') showed relatively strong suppressive activities in both antimutagenic and antipromotion assays compared with other seaweeds. These seaweeds contained considerable amounts of beta-carotene as a possible active principle with anticarcinogenic activity. This compound was partially associated with the antimutagenic activity in the seaweed extract, but did not contribute to the antipromotion activity of seaweed extract under our experimental conditions. These results strongly suggest that Japanese edible seaweeds have possible antimutagenic and antipromotion activities probably associated with antitumor activity.

3T3 Cells↗

PubMed1994

Dose-dependent inhibition of glutathione S-transferase placental form-positive hepatocellular foci induction in the rat by methyl propyl disulfide and propylene sulfide from garlic and onions.

Two organosulfur compounds, methyl propyl disulfide (MPD) and propylene sulfide (PS) from garlic and onions, were studied for their modifying effects on hepatocarcinogenesis in the F344 rats. Modifying potential was scored by comparing the number and area per cm2 of induced glutathione S-transferase placental form (GST-P)-positive foci in the liver. MPD and PS significantly reduced both these parameters of GST-P-positive foci in a dose-dependent manner. To investigate possible mechanisms of inhibition, ornithine decarboxylase (ODC) and spermidine/spermine N1-acetyltransferase (SAT) activities were measured. In MPD and PS-high dose-treated liver tissue there was a tendency for their decrease, albeit non-significant, which suggested that the inhibitory effect might have been caused by decreased cell proliferation associated with decreased polyamine biosynthesis. In evaluating relationships between diet and cancer, it is thus necessary to consider various effects in assessing possible protective roles of garlic and onions.

Allium↗

PubMed1994

Localization of Rabphilin-3A on the synaptic vesicle.

Rabphilin-3A is a putative target protein for Rab3A small GTP-binding protein which is implicated in neurotransmitter release. Rabphilin-3A is expressed mainly in brain, but its subcellular localization remains to be clarified. Immunohistochemical analysis has revealed that Rabphilin-3A is most abundant in the synaptic area of the rat cerebellum, retina, and neuromuscular junction. Ultrastructural analysis of the neuromuscular junction using the immunogold method indicates that Rabphilin-3A is localized on the synaptic vesicle. Subcellular fractionation analysis of rat brain has shown that Rabphilin-3A is most highly concentrated in the purified synaptic vesicle fraction. These results indicate that Rabphilin-3A is localized on the synaptic vesicle in the presynapse.

Adaptor Proteins, Signal Transducing↗

PubMed1994

Enhancement by organosulfur compounds from garlic and onions of diethylnitrosamine-induced glutathione S-transferase positive foci in the rat liver.

Ten organosulfur compounds from garlic and onions were studied for their modifying effects on diethylnitrosamine-induced neoplasia of liver in male F344 rats using the medium-term bioassay system of Ito based on the two-step model of hepatocarcinogenesis. Carcinogenic potential was scored by comparing the number and area per cm2 of induced glutathione S-transferase placental form-positive foci in the liver with those of the corresponding control group given diethylnitrosamine alone. In experiments 1 and 2, high doses of diallyl sulfide, diallyl trisulfide, allyl methyl sulfide, allyl methyl trisulfide, and dipropyl sulfide had enhancing effects on focus formation. In contrast, high doses of methyl propyl disulfide and propylene sulfide significantly decreased the number of glutathione S-transferase placental form-positive foci. In the third experiment, combined treatment with the five chemicals that had enhancing activity were fed at low doses and increased the induction of glutathione S-transferase placental form-positive foci. To investigate the mechanism of the modifying effect on hepatocarcinogenesis, ornithine decarboxylase activity was measured in diallyl sulfide-, allyl methyl sulfide-, and dipropyl sulfide-treated liver tissue without prior initiation with diethylnitrosamine, and its activity was increased compared to controls. Spermidine/spermine N1-acetyltransferase activity was not significantly changed. Formation of 8-hydroxydeoxyguanosine, a DNA adduct generated by activated oxygen species, and lipid peroxidation (2-thiobarbituric acid-reacting substance production) were also not changed. These results suggest that the promoting effect could be caused by increased cell proliferation with increased polyamine biosynthesis. In evaluating relationships between diet and cancer, it is appropriate to consider not only the possible protective role of garlic and onions but also their enhancing effects.

Allium↗

PubMed1994

The role of protein phosphorylation and cytoskeletal reorganization in microparticle formation from the platelet plasma membrane.

Platelets activated by various agonists produce vesicles (microparticles; MPs) from the plasma membrane. However, the mechanism of this MP formation remains to be elucidated. To investigate the possible involvement of protein phosphorylation and cytoskeletal reorganization in MP formation, the effects of various inhibitors on MP formation were investigated. Flow cytometry was employed to detect the amount of MP formation by using monoclonal antibodies against glycoprotein (GP) IIb-IIIa (NNKY 1-32) or GPIIb (Tab). The relationship between changes in cytoskeletal architecture and MP formation in the platelets activated by thrombin plus collagen was observed by scanning electron microscopy (SEM). MPs were observed in the vicinity of the terminals of pseudopods, suggesting that MPs may be related by budding of the pseudopods. Cytochalasin D (10 microM) inhibited MP formation from the activated platelets almost completely. Moreover, SEM of the cytochalasin D-treated platelets revealed the absence of shape change, pseudopod formation and MPs. These findings suggest that cytoskeletal reorganization is necessary for MP formation. Since cytoskeletal reorganization is considered to be regulated by a dynamic phosphorylation-dephosphorylation process, we investigated the effects of the protein phosphatase inhibitors, calyculin A (CLA) and okadaic acid (OA), on MP formation. Flow cytometry showed that these two inhibitors doubled MP formation in activated platelets. SEM of the platelets treated with CLA or OA demonstrated more prominent shape change and pseudopod formation in these platelets than in those without inhibitor. From these results, we conclude that cytoskeletal reorganization, which is controlled by phosphorylation, is involved in MP formation.

Adult↗

PubMed1994

Production of docosahexaenoic acid by marine bacteria isolated from deep sea fish.

Five bacterial strains isolated from the intestine of deep sea fish were shown to produce docosahexaenoic acid (22:6n-3; DHA) at a level of 6.4 to 11.6% of total fatty acids when incubated in DHA-free medium. In all of the strains examined, other polyunsaturated fatty acids were barely detectable, except for eicosapentaenoic acid (20:5n-3). A typical strain, such as T3615, produced DHA at a concentration of about 0.8 mg/L within six days of aerobic incubation at 5 degrees C and under atmospheric pressure. The T3615 strain, belonging to the genus Vibrio, is rod-shaped, Gram-negative, motile and facultatively anaerobic.

Animals↗

PubMed1994

Lp(a): an acute-phase reactant?

The present study was designed to confirm the transient increases of plasma Lp(a) levels as an acute-phase reactant and to clarify the significance of these increases with the use of patients with acute myocardial infarction and patients subjected to surgical operations. Although interleukin 6, C-reactive protein and alpha 1 antitrypsin reached the maximal levels 1-2 days, 3 days and 4-5 days, respectively, after the episodes, the peak time of Lp(a) levels was delayed some extent in both patient groups. Studying the transient increases of Lp(a) levels as a function of apo(a) isoforms analyzed by density-gradient ultracentrifugation and SDS-PAGE, the higher-density Lp(a) particles preferentially containing high-molecular-weight apo(a) isoforms increased more than the lower-density Lp(a) particles containing low-molecular-weight apo(a) after the episodes. The immunohistochemical findings suggest that Lp(a) may play an important role as an acute-phase reactant in the repair of tissue injury, especially in the process of angiogenesis.

Acute-Phase Reaction↗

PubMed1994

Quantitative determination of circulating platelet microparticles by flow cytometry.

Platelet microparticles are vesicles derived from the plasma membrane of platelets activated by a variety of agonists. To assess the extent of platelet activation, we recently developed a new and simple method of quantitating circulating microparticles in plasma by flow cytometry using the murine monoclonal antibody against glycoprotein IIb-IIIa (NNKY1-32). Using 2-microns fluorescent calibration beads, we succeeded in evaluating the absolute level of circulating microparticles. We determined the microparticle concentrations in 10 patients with arterial occlusive disease and in nine normal healthy donors, to determine whether the detection of microparticles would be useful in assessing the degree of platelet activation in clinical disorders. Microparticle levels were significantly higher in patients not treated with anti-thrombotic drugs than in normal healthy donors (P < 0.001), but not significantly higher in patients with vascular prostheses who had received anti-thrombotic drugs. These observations suggest the usefulness of microparticle quantitation in assessing the platelet activation in arterial occlusive diseases.

Adult↗

PubMed1994

First isolation of a rickettsia closely related to Japanese spotted fever pathogen from a tick in Japan.

In May 1993, we collected unfed ticks in Anan, Tokushima Prefecture, Shikoku District, Japan, a highly endemic area of Japanese spotted fever (JSF). We isolated JSF rickettsiae from these ticks by inoculating tick-emulsions into L-929 cells. Of the four genera and seven species of ticks examined, only one larva of Dermacentor taiwanensis Sugimoto yielded a rickettsial isolate. The isolate (DT-1 strain) was found to belong to the serotype common to the causative agent of JSF. This was based on its specific reactivity to mouse antisera and to a monoclonal antibody to JSF rickettsiae from the Shikoku District. This is the first tick-borne spotted fever group of rickettsia isolated in Japan. However, all stages of D. taiwanensis infrequently parasitize humans. Some ticks in the genus Haemaphysalis commonly infest humans and are frequently found to be rickettsia-positive in the hemolymph test when using the monoclonal antibody mentioned above. Therefore, the vectors of JSF rickettsiae to humans may be a complex of tick species.

Animals↗

PubMed1994

Prevalence of Lyme borrelia in ticks, especially Ixodes persulcatus (Acari: Ixodidae), in central and western Japan.

Prevalence of Lyme Borrelia in unfed ticks was surveyed in central and western Japan during spring from 1991 to 1993. The tick fauna was diverse; ticks obtained consisted of four genera and more than 12 identified species, and both southern and northern species coexist with altitudinal separation. Midguts of ticks were cultured in BSK medium for spirochetal isolation. Borrelia-positive rates for adults of both a common species, Ixodes ovatus Neumann, and a northern species, Ixodes persulcatus Schulze, in the extreme western part of the Japanese central mountainous zone (Fukui and Gifu prefectures) were 18.1 and 12.9%, respectively. A Borrelia-positive nymph of Haemaphysalis flava Neumann also was found for the first time in Japan. In contrast, I. persulcatus in southwestern Japan was localized in mountains with elevations over 800 m and was determined negative for Borrelia, whereas I. ovatus was highly positive (28.8%). These Borrelia isolates were diverse in typing of protein profiles. Our results reveal that I. persulcatus-borne Borrelia derived from northern Japan is kept within the limits of the western extremity of the central mountainous zone.

Animals↗

PubMed1994

Enhancing effects of organosulfur compounds from garlic and onions on hepatocarcinogenesis in rats: association with increased cell proliferation and elevated ornithine decarboxylase activity.

Four organosulfur compounds from garlic and onions were examined for modifying effects on diethylnitrosamine (DEN)-induced neoplasia of the liver in male F344 rats using the medium-term bioassay system based on the two-step model of hepatocarcinogenesis. Carcinogenic potential was scored by comparing the numbers and areas per cm2 of induced glutathione S-transferase placental form-positive foci. Isothiocyanic acid isobutyl ester (IAIE), dipropyl trisulfide (DPT), and allyl mercapton (AM) exerted enhancing effects on their development, while dimethyl trisulfide also tended to increase them. To investigate possible mechanisms of the modifying influence, sequential changes in ornithine decarboxylase activity (ODC) over 24 h were measured in AM-treated liver tissue without prior DEN initiation. The activity started to increase by 4 h after AM-treatment, and reached maximum at 16 h, compared to controls. Spermidine/spermine N1-acetyltransferase activity was not significantly changed. An increase in proliferating cell nuclear antigen-positive cells followed the elevation of ODC activity. These results suggest that IAIE, DPT, and AM promote rat hepatocarcinogenesis and their promoting effect might be caused by increased cell proliferation with increased polyamine biosynthesis. In evaluating relationships between diet and cancer, it is thus appropriate to consider not only a possible protective role of garlic and onions, but also enhancing effects.

Acetyltransferases↗

PubMed1994

New method for isolating barophiles from intestinal contents of deep-sea fishes retrieved from the abyssal zone.

We devised a new method (the dorayaki method) using marine agar under in situ pressures to isolate barophilic bacteria from the intestinal contents of three deep-sea fishes (two Coryphaenoides yaquinae samples and one Ilyophis sp. sample) retrieved from depths of 4,700 to 6,100 m in the Northwest Pacific Ocean. All 10 strains isolated from one sample (C. yaquinae) were obligately barophilic. One of the 10 strains did not grow at atmospheric pressure and 103.4 MPa but did grow well between 20.7 and 82.7 MPa, with optimal growth at 41.4 MPa. This method is useful for isolating psychrophilic and barophilic deep-sea bacteria.

Journal Article↗

PubMed1994

Effect of insulin on water and urea transport in the inner medullary collecting duct.

The effect of insulin on water and urea transport was examined in normal isolated rat inner medullary collecting duct (IMCD). Hydraulic conductivity (Lp, x 10(-6) cm.atm-1.s-1), diffusional water permeability (Pdw, x 10(-5) cm/s) and [14C]urea permeability (x 10(-5) cm/s) were studied at 37 degrees C and pH 7.4. Insulin (6 x 10(-8) M; 200 microU/ml) added to the bath fluid enhanced Lp from 0.40 +/- 0.10 to 1.21 +/- 1.40 (P < 0.01) and Pdw from 42.40 +/- 3.40 to 58.50 +/- 5.00 (P < 0.02) and also stimulated Lp in a dose-dependent manner. In the presence of antidiuretic hormone (ADH)-stimulated Pdw (10 microU/ml), insulin increased Pdw even more. Prostaglandin E2 (10(-5) M) added to the bath reversibly increased insulin-induced Lp. Forskolin (10(-4) M) blocked the action of insulin. Colchicine (10(-4) M) and V1-receptor antagonist (10(-4) M) inhibited the development but not the maintenance of insulin-stimulated Pdw. Vanadate (2.5 x 10(-6) M) enhanced Pdw. Polymyxin B (10(-5) M) inhibited the insulin-stimulated Pdw, whereas in a glucose-free medium insulin did not enhance Pdw. Urea transport was not affected by insulin. These data suggest that insulin may enhance water transport, probably by stimulating glucose transporters, which would serve as a water channel. We cannot rule out the possibility that insulin may be eliciting existing ADH-like mechanisms of water transport, beyond the microtubule step, to establish water transport.

Animals↗

PubMed1994

Coexpression of glucose transporters and glucokinase in Xenopus oocytes indicates that both glucose transport and phosphorylation determine glucose utilization.

A Xenopus oocyte expression system was used to examine how glucose transporters (GLUT 2 and GLUT 3) and glucokinase (GK) activity affect glucose utilization. Uninjected oocytes and low rates of both glucose transport and phosphorylation; expression of GLUT 2 or GLUT 3 increased glucose phosphorylation approximately 20-fold by a low Km, endogenous hexokinase at glucose concentrations < or = 1 mM, but not at higher glucose concentrations. Coexpression of functional GK isoforms with GLUT 2 or 3 increased glucose utilization approximately an additional two- to threefold primarily at the physiologic glucose concentrations of 5-20 mM. The Km for glucose of both the hepatic and beta cell isoforms of GK, determined in situ, was approximately 5-10 mM when coexpressed with either GLUT 2 or GLUT 3. The increase in glucose utilization by coexpression of GLUT 3 and GK was dependent upon glucose phosphorylation since two missense GK mutations linked with maturity-onset diabetes, 182: Val-->Met and 228:Thr-->Met, did not increase glucose utilization despite accumulation of both a similar amount of immunoreactive GK protein and glucose inside the cell. Coexpression of a mutant GK and a normal GK isoform did not interfere with the function of the normal GK enzyme. Since the coexpression of GK and a glucose transporter in oocytes resembles conditions in the hepatocyte and pancreatic beta cell, these results indicate that increases in glucose utilization at glucose concentrations > 1 mM depend upon both a functional glucose transporter and GK.

Animals↗

PubMed1994

Effect of amphotericin B on water and urea transport in the inner medullary collecting duct.

The clinical usefulness of amphotericin B (AMP-B) is limited by its nephrotoxicity, as characterized by decreased RPF, decreased GFR, impaired urinary acidification, and potassium excretion defects. Defects of renal concentrating ability have been noted, but the mechanisms responsible for them have not been investigated. The chief objective of this research was to analyze directly the effect of AMP-B on arginine-vasopressin (AVP)- or dibutyrl cAMP (DcAMP)-stimulated water and urea transport of the inner medullary collecting duct (IMCD) obtained from rats by the in vitro microperfusion technique. AMP-B (10(-5) M) added to the bath fluid in the absence of AVP did not impair the hydraulic conductivity (Lp) and the urea permeability (Pu) of rat IMCD. AMP-B (10(-5) M) added to the bath fluid decreased the AVP-stimulated Lp (x 10(-6) cm/s.atm) of rat IMCD from 19.41 +/- 2.19 to 10.00 +/- 1.39 (P < 0.001), and the reversibility of its action was observed during a third period when Lp increased to 19.80 +/- 2.19 (P < 0.001) after the initial conditions were restored. In addition, AMP-B reduced DcAMP-stimulated Lp from 20.95 +/- 1.75 to 10.52 +/- 0.71 (P < 0.01) in a reversible manner when the drug was withdrawn from the bath. AMP-B also decreased AVP-stimulated Pu (x 10(-5) cm/s) when added to the bath fluid from 36.60 +/- 2.05 to 29.88 +/- 1.36 (P < 0.001), and this effect was reversible after AMP-B was withdrawn from the bath (37.40 +/- 1.36; P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Amphotericin B↗

PubMed1994

[Invasive treatment of ischemic events after coronary artery bypass grafting].

PTCA or reCABG was performed for ischemic events after CABG in 32 patients. Since 6 patients were operated on initially elsewhere, the incidence of reCABG among our own patients was 1.2% and that of PTCA was 4.5%. Only one patient of 15 patients, in whom internal thoracic artery (ITA) was utilized at the initial CABG, underwent reCABG and the other patients were treated by PTCA. The use of ITA reduced the necessity for re-CABG because of the superior long-term patency of ITA. PTCA was performed for 32 lesions (19 in saphenous vein grafts (SVG), 4 in ITA grafts, and 9 in native coronary arteries) of 23 patients with success rate of 88%. The rate of restenosis was 36%. There were no complications following PTCA. No patients were referred for emergent surgery. Intracoronary thrombolysis and PTCA for total occlusion of SVG were performed successfully if they were done early after the occurrence of ischemic events. Coronary angiography should be performed as soon as possible. Ten patients underwent re-CABG utilizing ITA in 9 patients and gastro-epiploic artery (GEA) in 3. One patient died of arrhythmia due to spasm. The other 9 patients were discharged and class I or II of NYHA functional classification. The coronary angiography, which was performed at the late follow-up period, showed occlusion of SVG and patency of ITA. The arterial conduits should be applied for reCABG because of the low long-term patency of SVG.

Adult↗

PubMed1994

[Repeated valvular surgery with minimal heart dissection].

Between April 1989 and March 1994, sixteen patients underwent the reoperation for valvular disease. In early years, complete heart dissection performed during operation (group A, n = 7). And recently, minimal necessary dissection was applied (group B, n = 9). In group B, dissection was limited to the ascending aorta, both vena cavae and right upper pulmonary vein. If the adhesion would be dense, pleural cavity would be widely opened and both caval cannula and left atrial vent tube would be cannulated through pleural adhesion. Operation time of group B was significantly decreased in comparison with group A. (group A: 569 +/- 91 min, group B: 347 +/- 65 min, p < 0.01). Post-operative course of group B was considered to be better than group A. These result suggested that minimal necessary heart dissection would be extremely effective during the repeated valvular surgery.

Dissection↗

PubMed1994

[Experience with atrioventricular valve replacement in infants and children].

From 1980 to 1989, nine infants and children underwent valve replacement. These replacements consisted of seven mitral valve replacement (MVR), one left atrioventricular valve replacement, and one aortic valve (AVR) replacement. We excluded AVR from this report. Follow-up period of 8 cases were 68 months in an average. During this period, 2 cases were not thought to be satisfactory as antithrombotic therapy, in which one revealed malfunctioning prosthesis, and secondary MVR implantation was performed. Another one is free from any complications. We experienced the difficulty of antithrombotic therapy following valve replacement in infants and children. It is supposed that combined use of anticoagulant therapy agent and antiplatelet agent may be necessary as antithrombotic therapy, especially in childhood.

Adolescent↗