Biomedical subjects

M Eto

Publications and source records attributed to M Eto.

At least 55 records · Page 3Linked to original sources

PubMed2000

Detection of the association between a deletion polymorphism in the gene encoding angiotensin I-converting enzyme and advanced diabetic retinopathy.

We investigated the relationship between advanced diabetic retinopathy (ADR) and an angiotensin-converting enzyme (ACE) gene polymorphism in subjects with type 2 diabetes and ADR, pre-proliferative (PrePDR) or proliferative diabetic retinopathy (PDR) without overt nephropathy. Polymerase chain reactions were used to detect insertion/deletion (I/D) polymorphisms of the ACE gene. There was no difference in the frequency of II, ID, or DD genotypes, or of I and D alleles among subjects with type 2 diabetes without diabetic retinopathy (NDR) or with simple diabetic retinopathy (SDR) and non-diabetic controls. There was also no difference in the frequency of ACE genotypes among subjects with type 2 diabetes with NDR, or SDR and ADR. However, the frequency of the ACE DD genotype in ADR was significantly higher than that in controls (chi(2)=6.64, P=0.036). On the other hand, the frequency of the D allele in ADR was significantly higher than that in controls (chi(2)=6.33, P=0.012), NDR (chi(2)=4.18, P=0.041) and SDR (chi(2)=4. 89, P=0.027), respectively. These results indicate a significant relationship between the presence of the D allele polymorphism in the ACE gene and ADR in Japanese subjects with type 2 diabetes and no overt nephropathy.

Albuminuria↗

PubMed2000

Docking study of enantiomeric fonofos oxon bound to the active site of Torpedo californica acetylcholinesterase.

Molecular interaction between enantiomeric fonofos oxon (O-ethyl S-phenyl ethylphosphonothiolate) and acetylcholinesterase (AChE) of Torpedo californica was evaluated by using the Cerius2 program. It was suggested that the difference in the inhibitory activity of the two enantiomers of fonofos oxon on AChE is due to the steric hindrance in binding to the AChE active site.

Acetylcholinesterase↗

PubMed2000

Quantitative structure-activity studies of octopaminergic agonists and antagonists against Locusta migratoria using similarity indexes.

The quantitative structure-activity relationship of 39 octopamine (OA) agonists and 12 antagonists against the thoracic nerve cord of the migratory locust, Locusta migratoria L. was analyzed using atom based rigid fit method or flexible fitting offered by PowerFit 1.0 from MicroSimulation. For OA agonists, the more similar to reference compound NC (24) the structure of test compound, the higher the activity, whereas for OA antagonists it was not the case. Antagonists may not interact with the same part of the membrane with which the agonists interact. Taken the part of the membrane with which the agonist interacts as the true receptor, the antagonist may well interact with an area surrounding the receptor including the ionophore.

Animals↗

PubMed2000

Molecular orbital studies on pericyclic reactions of cinnamyl xanthates in beta-cyclodextrin cavities.

The solid beta-cyclodextrin (beta-CyD) complex of O-cinnamyl S-methyl dithiocarbonates (xanthate, 1a), upon heating at 45 degrees C, underwent asymmetric [3,31-sigmatropic rearrangement to give the optically S-(1-phenylallyl) S-methyl dithiocarbonate (2a) with 60% ee. Heating the beta-CyD complex of 2a at 120 degrees C caused extrusion of COS to give cinnamyl methyl sulfide (3a) in high yield. The reaction behavior and role of beta-CyD are discussed based on molecular orbital calculation data.

Chemical Phenomena↗

PubMed2000

Association of coronary risk factors and endothelium-dependent flow-mediated dilatation of the brachial artery.

Impaired endothelial function has been reported to be the initial step in atherosclerosis. Some coronary risk factors independently relate to impaired endothelial function. However, few studies have examined the association between coronary risk factors and endothelial function in patients who have multiple risk factors without clinical atherosclerosis. This study was undertaken to elucidate the relationship between accumulation of coronary risk factors and vascular endothelial dysfunction. We examined 101 subjects with one or more coronary risk factors 56.8 +/- 1.0 years old and 40 age-matched control subjects without coronary risk factors. We measured brachial artery diameter non-invasively using a 7.5-MHz ultrasound machine at rest, during reactive hyperemia caused by endothelium-dependent vasodilatation, and after sublingual administration of nitroglycerin, which causes endothelium-independent vasodilatation. The percentage change in flow-mediated diameter (%FMD; deltaD/D x 100), in subjects with one or more coronary risk factors was significantly lower than that in control subjects(4.8 +/- 0.3% vs. 6.7 +/- 0.5%, p < 0.01). Endothelium-independent vasodilatation by nitroglycerin did not differ between the two groups. Endothelial function was impaired according to the accumulation of coronary risk factors. On multiple regression analysis, the number of risk factors, age, and brachial artery diameter at rest showed significant correlation with %FMD. Our results suggest that an accumulation of coronary risk factors was significantly related to impairment of endothelial function.

Arteriosclerosis↗

PubMed2000

Pericardial constriction due to malignant lymphoma.

We experienced a case of T-cell lymphoma demonstrating diastolic heart failure as an initial manifestation. An 81-year-old Japanese male was admitted to the University of Tokyo Hospital because of progressive dyspnea and general fatigue. Clinical presentation was congestive heart failure and cervical lymphadenopathy. Right heart catheterization revealed "dip and plateau" waveforms in right ventricular pressure, which suggested a constrictive nature of heart failure. Gallium scintigram showed marked uptake in the heart. Biopsy from a cervical lymph node confirmed the diagnosis of malignant lymphoma of T-cell origin. Diastolic heart failure remained after successful chemotherapy. Autopsy revealed pericarditis with severe adhesion of the pericardium and the epicardium.

Aged↗

PubMed2000

Antitumor activity of interleukin-12 against murine bladder cancer.

PURPOSE: We investigated the antitumor activity of interleukin-12 (IL-12) against MBT-2, a murine bladder carcinoma, to clarify whether or not IL-12 is effective against urothelial tumors. MATERIALS AND METHODS: MBT-2, a murine carcinogen-induced, poorly differentiated transitional cell carcinoma of C3H/He origin, was used. Three or 10 days after the subcutaneous administration of MBT-2 cells, C3H/He mice were injected intraperitoneally with IL-12 five times per wk. for 2 wk. Tumor growth was measured twice weekly. Spleen cells from the C3H/He mice that had rejected MBT-2 after the IL-12 treatment were examined for MBT-2-specific cytolytic T lymphocytes (CTL) activity and cytokine production. RESULTS: Tumor growth and acceptance was obviously suppressed when C3H/He mice were treated with IL-12 from 3 days after the tumor inoculation. In the spleen cells from the C3H/He mice that had rejected MBT-2, MBT-2-specific CTL activity and secretion of IL-2 and interferon (IFN)-gamma were clearly detected. However, the established MBT-2 tumor cells were not rejected when C3H/He mice were given IL-12 from 10 days after the tumor inoculation, although the tumor growth was transiently suppressed during the IL-12 treatment. CONCLUSION: These data demonstrate that IL-12 is considerably effective against murine bladder cancer and suggest the clinical application of IL-12 against human bladder cancer.

Adjuvants, Immunologic↗

PubMed1999

A novel phosphoprotein inhibitor of protein type-1 phosphatase holoenzymes.

Control of protein phosphatases is now understood to depend on binding to a variety of regulatory or targeting subunits to form holoenzymes with restricted localization and substrate specificity. In addition, the catalytic subunits of both type-1 and type-2 phosphatases bind specific inhibitor proteins. Here, we report discovery of a new inhibitor protein called PHI-1 that is specific for type-1 protein phosphatase (PP1). Recombinant tagged PHI-1 was phosphorylated by protein kinase C at two sites, one a Ser and one a Thr; phosphorylation enhanced inhibitory potency 50-fold. Mutation of Thr57 to Ala gave a protein phosphorylated only on Ser, without change in inhibitory activity, indicating that phosphorylation of Thr57 was required for full activity. Immunoblotting showed that PHI-1 was expressed in most animal tissues and several cell lines, and a second larger protein called PHI-2 was present in different muscles, especially cardiac muscle. Unlike any other known inhibitor, PHI-1 inhibited the myosin- and glycogen-associated holoenzyme versions of PP1 as well as the monomeric catalytic subunit of PP1. Discovery of PHI-1 and PHI-2 opens new possibilities for regulation of PP1 via phosphorylation-dependent signaling pathways.

Animals↗

PubMed1999

Advanced glycation end product-induced peroxisome proliferator-activated receptor gamma gene expression in the cultured mesangial cells.

We identified the AGEs-induced expression of peroxisome proliferator-activated gamma (PPAR gamma) in the cultured mesangial cells using reverse transcription-polymerase chain reaction, electrophoretic mobility shift assay (EMSA), and Western immunoblotting. Administration of AGEs-BSA into the cultured mesangial cells resulted in an increase in the levels of mRNA and proteins for PPAR gamma in a dose-dependent manner. Specific bands which indicate the protein binding to PPAR gamma responsive element (PPRE) in the nuclear extracts were also detected in AGEs-BSA-treated mesangial cells, but not found in BSA-treated cells by EMSA. Antioxidants, NAC, PDTC, and aminoguanidine, attenuated the gene expression and activity of PPAR gamma induced by AGEs. These results indicate that PPAR gamma was induced and activated by the oxidative signal(s) evoked by AGEs-ligand-receptor interactions. AGEs-induced gene expression of PPAR gamma and the signal intensity of PPAR gamma and PPRE complex were attenuated furthermore by protein kinase C inhibitors, calphostin C and staurospolin, but not abolished completely, indicating that both signal transduction pathways through the induction of PKC activation and independent of PKC activation were involved in the AGEs-mediated expression and activation process of PPAR gamma. AGEs also increased the gene expression of smooth muscle alpha-actin, which is a marker for phenotypic change in mesangial cells. It is suggested therefore that AGEs-induced transcription factor as the oxidative stress may have a role in the differentiation of mesangial cells.

Actins↗

PubMed1999

Reconstitution of protein kinase C-induced contractile Ca2+ sensitization in triton X-100-demembranated rabbit arterial smooth muscle.

1. Triton X-100-demembranated smooth muscle loses Ca2+-sensitizing responsiveness to protein kinase C (PKC) activators while intact and alpha-toxin-permeabilized smooth muscles remain responsive. We attempted to reconstitute the contractile Ca2+ sensitization by PKC in the demembranated preparations. 2. Western blot analyses showed that the content of the PKC alpha-isoform (PKCalpha) was markedly reduced and that the smooth muscle-specific protein phosphatase-1 inhibitor protein CPI-17 was not detectable, while the amount of calponin and actin still remained similar to those of intact strips. 3. Unphosphorylated recombinant CPI-17 alone induced a small but significant contraction at constant Ca2+. Isoform-selective PKC inhibitors inhibited unphosphorylated but not pre-thiophosphorylated CPI-17-induced contraction, suggesting that in situ conventional PKC isoform(s) can phosphorylate CPI-17. 4. Exogenously replenishing PKCalpha alone did not induce potentiation of contraction and only slowly increased myosin light chain (MLC) phosphorylation at submaximal Ca2+. 5. PKC in the presence of CPI-17, but not the [T38A]-CPI mutant, markedly induced potentiation of both contraction and MLC phosphorylation. CPI-17 itself was phosphorylated. 6. In in vitro experiments, CPI-17 was a much better substrate for PKCalpha than calponin, caldesmon, MLC and myosin. 7. Our results indicate that PKC requires CPI-17 phosphorylation at Thr-38 but not calponin for reconstitution of the contractile Ca2+ sensitization in the demembranated arterial smooth muscle.

Animals↗

PubMed1999

Effect of octopamine on the activity of juvenile-hormone esterase in the silkworm Bombyx mori and the red flour beetle Tribolium freemani.

This study focuses on the effect of octopamine (OA) on metamorphosis of the silkworm Bombyx mori and the red flour beetle Tribolium freemani Hinton. Titers of OA and juvenile-hormone esterase (JHE) were measured at various larval and pupal stadia of both insects. Effects of OA, OA agonists, and antagonists on metamorphosis and JHE activity were also examined. At day 2, peaks of OA and JHE activity were observed in third instars, and at day 3, a sharp peak of OA was observed, followed by a large peak of JHE activity at day 4 in last instars of B. mori. However, no peaks of OA and JHE activity were observed in fourth instars. A high titer of OA appeared at days 2-4, followed by a peak of JHE activity at day 7 and the second OA peak at day 9 after the start of assay of T. freemani. At pupation, a small peak of OA and the highest activity of JHE were observed. The effects of OA on JHE activity were examined in vitro, because the relationship could be responsible for triggering pupation in B. mori and T. freemani larvae. Exogeneous OA (0.1-10 mM) stimulated the JHE activity of final instars (day 2) of B. mori in vitro. Similarly, the presence of OA (10 mM) activated the JHE activity of newly ecdysed T. freemani pupae in vitro. OA antagonists chlorpromazine and gramine delayed the start of spinning and reduced the JHE activity of B. mori, when applied in diet at 10-100 ppm. Some OA agonists stimulated the pupation and JHE activity of T. freemani larvae reared under crowded conditions, when topically applied. Thus, OA may contribute to activation of the events preparatory to a pupal molt, i.e., the secretion of OA increases JHE activity followed by stimulation of pupation.

Animals↗

PubMed1999

Titres of biogenic amines and ecdysteroids: effect of octopamine on the production of ecdysteroids in the silkworm Bombyx mori.

At day two, a sharp peak of octopamine (OA) was observed in last instar female Bombyx mori larvae. This peak also appeared in male larvae a day later than in females at day three. An OA peak was also observed before the 3rd ecdysis. However, no OA peaks were observed in 4th instar larvae. At day eight and nine of the 5th instar, another OA peak was observed for male and female, respectively. A peak of tyramine (TA) was found at day one followed by a peak of OA at day two in 3rd instar larvae. At day two, a day before OA peak, a peak of TA was observed for male insects and before the 2nd peak of OA, TA titre was also high in 5th instar larvae. Immediately after 3rd ecdysis, a high titre of DL-beta-(3,4-dihydroxyphenyl)alanine (DOPA) was observed, followed by a peak of dopamine (DA) at day five. A peak of DOPA was found at day one followed by a peak of DA at day two in 3rd instar larvae. Similarly, a small peak of DOPA was observed at day two, followed by an increase of DA at days eight and nine after the 4th ecdysis. Ecdysteroid peaks were observed just before the 3rd and 4th ecdysis and an ecdysteroid titre increased after the start of spinning. The effects of OA and JH on production of ecdysteroids by prothoracic glands (PGs) were examined in order to identify neuromediators responsible for triggering pupation in B. mori larvae. Exogeneous OA (10-100 mM) reduced and 10 &mgr;M OA stimulated the production of ecdysteroids in the presence and absence of brain extracts by PGs in the final instar (day five) of B. mori in vitro. Meanwhile, exogeneous JHI (10 &mgr;g/ml) stimulated and at 5 &mgr;g/ml it reduced production of ecdysteroids in the presence of brain extracts. Gramine, an OA antagonist, delayed pupation when applied in the diet. Thus, OA may produce some biological effects on the programming of larval-pupal development.

Journal Article↗

PubMed1999

Three-dimensional pharmacophore hypotheses for the locust neuronal octopamine receptor (OAR3). Part 2: agonists.

Three-dimensional pharmacophore hypotheses were built from a set of 43 agonists against octopamine receptor class 3 (OAR3) in locust nervous tissue. Among the 10 chemical-featured models generated by program Catalyst/Hypo, a hypothesis including hydrogen-bond acceptor (HBA), hydrophobic (Hp), and hydrophobic aliphatic (HpA1) features was considered to be important and predictive in evaluating OAR3 agonists. While the ideal and null hypotheses had a cost of 156.40 and 239.20, respectively, the 10 resulting hypotheses possessed costs from 169.89 to 175.81. The best hypothesis that was confirmed to have a 95% chance of true correlation yielded a low RMS of 0.757 and high regression r of 0.933. Active agonists mapped well onto all the features of the hypothesis such as HBA, Hp, and HpA1. On the other hand, inactive compounds were shown to be difficult to achieve the energetically favorable conformation which is found in the active molecules in order to fit the 3-D chemical feature pharmacophore models.

Animals↗

PubMed1999

Importance of intrathymic mixed chimerism for the maintenance of skin allograft tolerance across fully allogeneic antigens in mice.

In B6 (H-2b) mice that had been given, neonatally, 1x108 B6AKF1 spleen cells intraperitoneally (i.p.), only a moderate prolongation of donor (AKR:H-2k) skin graft survival was observed. In such B6 mice, no mixed lymphocyte reaction (MLR) to AKR could be detected on day 35 (35 days after birth), but it was clearly evident on day 84. Similarly, neither Vbeta6+ (reactive to MTV-7-encoded antigens) nor Vbeta11+ (reactive to I-E+MTV-derived superantigens) T cells were detected on day 35, but both were clearly evident on day 84 in both the thymus and the lymph nodes, thus indicating the breakdown of intrathymic mixed chimerism at the antigen-presenting cell level. Furthermore, by day 84, all skin grafts from AKR had already been rejected in such B6 mice. In the periphery, however, Vbeta6+, but not Vbeta11+, T cells were clonally anergic on day 84, based on a stimulation assay with anti-T-cell receptor (TCR) monoclonal antibody (mAb), thus suggesting that tolerance to some antigens, but not to others, may be induced by the clonal anergy in fully allogeneic combinations, and that the clonal anergic state may be masked by other proliferative responses. These results therefore indicate the importance of intrathymic mixed chimerism (central tolerance) and the limitations of clonal anergy (peripheral tolerance) in maintaining tolerance across fully allogeneic antigen barriers.

Animals↗

PubMed1999

Surgical excision of a metastatic adrenal lesion in a patient with prostatic cancer.

BACKGROUND: A 64-year-old Japanese man with stage D2 prostatic cancer, after having responded dramatically to androgen ablation, demonstrated a solitary adrenal metastasis without disease progression to any other site. METHODS: A surgical excision of the lesion and adjuvant systemic chemotherapy was performed. RESULTS/CONCLUSIONS: The patient has since remained alive without any evidence of recurrence 21 months after surgery.

Adenocarcinoma↗

PubMed1999

Soy protein peptic hydrolysate with bound phospholipids decreases micellar solubility and cholesterol absorption in rats and caco-2 cells.

This experiment was designed to evaluate the effects of casein, soy protein, soy protein with bound phospholipids (SP), soy protein peptic hydrolysate (SPH) or soy protein peptic hydrolysate with bound phospholipids (SPHP) on the micellar solubility of cholesterol and the taurocholate binding capacity in vitro. We also evaluated the effects of various proteins on cholesterol metabolism in rats and Caco-2 cells. SPHP had a significantly greater bile acid-binding capacity than that of SPH in vitro. Micellar cholesterol solubility in vitro was significantly lower in the presence of SPHP compared to casein tryptic hydrolysate (CTH). The cholesterol micelles containing SPHP and SPH significantly suppressed cholesterol uptake by Caco-2 cells compared to the cholesterol micelles containing CTH. Consistent with these findings in the in vivo cholesterol absorption study using radioisotopes, fecal excretion of total steroids was significantly greater in rats fed the SPHP diet compared with those fed the casein, soy protein, SP and SPH diets. Serum total cholesterol was significantly lower in rats fed SPHP than in those fed casein. The concentrations of total lipids and cholesterol in liver were significantly lower in the SPHP-fed group compared with all other groups. These results suggest that the suppression of cholesterol absorption by direct interaction between cholesterol-mixed micelles and SPHP in the jejunal epithelia is part of the mechanism underlying the hypocholesterolemic action of SPHP. SPHP may also inhibit the reabsorption of bile acids in the ileum, thus lowering the serum cholesterol level.

Amino Acids↗

PubMed1999

Localization of 17-kDa myosin light chain isoforms in cultured aortic smooth muscle cells.

Smooth muscle myosin II contains two 17-kDa essential light chain isoforms (LC17gi and LC17nm) of which the relative contents differ among myosins. To understand the roles of LC17 isoforms in the functions of myosin, we performed an immunofluorescence microscopic examination of their localization in primary cultured cells isolated from rat aortic smooth muscle. To identify the isoforms, rabbit polyclonal antibodies were prepared against C-terminal nonapeptides corresponding to either LC17gi or LC17nm from porcine aortic smooth muscle myosin. These isoforms differ in only 5 amino acid residues within the C-terminal 9 residues. These antibodies specifically recognize each LC17 isoform on urea-PAGE of total rat aortic cell lysates. Immediately after plating, the smooth muscle cells stained heterogeneously with each antibody, indicating differing contents of LC17 isoforms among cells. On double staining 1-2 d cultures with both antibodies, LC17nm was detected diffusely throughout the cytoplasm, whereas LC17gi was concentrated in specific regions such as the cell periphery and the base of cytoplasmic processes. These results support the suggestion that myosin containing LC17gi is essential for force-generation by aortic smooth muscle and that myosin containing LC17nm may play an important role in maintaining smooth muscle tension.

Animals↗

PubMed1999

Identification of trimeric myosin phosphatase (PP1M) as a target for a novel PKC-potentiated protein phosphatase-1 inhibitory protein (CPI17) in porcine aorta smooth muscle.

CPI17, a phosphorylation-dependent inhibitory protein of protein phosphatase-1 (PP1), is dominantly expressed in smooth muscle, and the inhibitory activity is potentiated by protein kinase C and its related enzymes [Eto, M. et al. (1997) FEBS Lett. 410, 356-360]. In order to identify its physiological target in smooth muscle, the myofibrillar extract from porcine aorta media was analyzed by affinity chromatography on CPI17-conjugated Sepharose. The binding of phosphatases to the resin depended on thiophosphorylation of CPI17, and about 90% of the phosphatase activities toward phosphorylated myosin (p-myosin) and phosphorylase-a were bound to the resin and could be eluted with 0.5 M NaCl. The IC50 values of thiophosphorylated CPI17 toward phosphatases bound to the resin were in the range of 0.5-3 nM, as expected for the PP1 holoenzymes sensitive to CPI17. The CPI17-sensitive fraction was further separated into several peaks of phosphatase activity by column chromatography on Mono Q, which suggested multiple functions of CPI17 as a mediator of the protein kinase C-related signal transduction pathway in aorta smooth muscle. The major activity toward p-myosin was identified as the myofibril-bound PP1 (PP1M), and its subunit composition (140, 37, and 20 kDa) was consistent with that of PP1M from chicken gizzard and porcine bladder. The purified PP1M was completely inhibited by phosphorylated and thiophosphorylated CPI17. Kinetic analysis showed mixed inhibition of PP1M by CPI17 (Ki = 1.9 nM and Ki' = 5.1 nM). The concentration of CPI17 in aorta smooth muscle cells was estimated to be at least 0. 3 microM from the result of Western analysis. This concentration appears to be sufficient to suppress the in situ PP1M in aorta smooth muscle, and PP1M is thus identified as a target of CPI17 in vascular smooth muscle.

Amino Acid Sequence↗