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Bennett PB, Yazawa K, Makita N, George AL. Molecular mechanism for an inherited cardiac arrhythmia. Nature 1995; 376:683-5. [PMID: 7651517 DOI: 10.1038/376683a0] [Citation(s) in RCA: 635] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In the congenital long-QT syndrome, prolongation of the cardiac action potential occurs by an unknown mechanism and predisposes individuals to syncope and sudden death as a result of ventricular arrhythmias. Genetic heterogeneity has been demonstrated for autosomal dominant long-QT syndrome by the identification of multiple distinct loci, and associated mutations in two candidate genes have recently been reported. One form of hereditary long QT (LQT3) has been linked to a mutation in the gene encoding the human heart voltage-gated sodium-channel alpha-subunit (SCN5A on chromosome 3p21). Here we characterize this mutation using heterologous expression of recombinant human heart sodium channels. Mutant channels show a sustained inward current during membrane depolarization. Single-channel recordings indicate that mutant channels fluctuate between normal and non-inactivating gating modes. Persistent inward sodium current explains prolongation of cardiac action potentials, and provides a molecular mechanism for this form of congenital long-QT syndrome.
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Metz JG, Roessler P, Facciotti D, Levering C, Dittrich F, Lassner M, Valentine R, Lardizabal K, Domergue F, Yamada A, Yazawa K, Knauf V, Browse J. Production of polyunsaturated fatty acids by polyketide synthases in both prokaryotes and eukaryotes. Science 2001; 293:290-3. [PMID: 11452122 DOI: 10.1126/science.1059593] [Citation(s) in RCA: 484] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Polyunsaturated fatty acids (PUFAs) are essential membrane components in higher eukaryotes and are the precursors of many lipid-derived signaling molecules. Here, pathways for PUFA synthesis are described that do not require desaturation and elongation of saturated fatty acids. These pathways are catalyzed by polyketide synthases (PKSs) that are distinct from previously recognized PKSs in both structure and mechanism. Generation of cis double bonds probably involves position-specific isomerases; such enzymes might be useful in the production of new families of antibiotics. It is likely that PUFA synthesis in cold marine ecosystems is accomplished in part by these PKS enzymes.
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Wang DW, Yazawa K, George AL, Bennett PB. Characterization of human cardiac Na+ channel mutations in the congenital long QT syndrome. Proc Natl Acad Sci U S A 1996; 93:13200-5. [PMID: 8917568 PMCID: PMC24070 DOI: 10.1073/pnas.93.23.13200] [Citation(s) in RCA: 204] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The congenital long QT syndrome (LQTS) is an inherited disorder characterized by a prolonged cardiac action potential. This delay in cellular repolarization can lead to potentially fatal arrhythmias. One form of LQTS (LQT3) has been linked to the human cardiac voltage-gated sodium channel gene (SCN5A). Three distinct mutations have been identified in the sodium channel gene. The biophysical and functional characteristics of each of these mutant channels were determined by heterologous expression of a recombinant human heart sodium channel in a mammalian cell line. Each mutation caused a sustained, non-inactivating sodium current amounting to a few percent of the peak inward sodium current, observable during long (> 50 msec) depolarizations. The voltage dependence and rate of inactivation were altered, and the rate of recovery from inactivation was changed compared with wild-type channels. These mutations in diverse regions of the ion channel protein, all produced a common defect in channel gating that can cause the long QT phenotype. The sustained inward current caused by these mutations will prolong the action potential. Furthermore, they may create conditions that promote arrhythmias due to prolonged depolarization and the altered recovery from inactivation. These results provide insights for successful intervention in the disease.
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Ohgami K, Shiratori K, Kotake S, Nishida T, Mizuki N, Yazawa K, Ohno S. Effects of astaxanthin on lipopolysaccharide-induced inflammation in vitro and in vivo. Invest Ophthalmol Vis Sci 2003; 44:2694-701. [PMID: 12766075 DOI: 10.1167/iovs.02-0822] [Citation(s) in RCA: 195] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Astaxanthin (AST) is a carotenoid that is found in marine animals and vegetables. Several previous studies have demonstrated that AST exhibits a wide variety of biological activities including antioxidant, antitumor, and anti-Helicobacter pylori effects. In this study, attention was focused on the antioxidant effect of AST. The object of the present study was to investigate the efficacy of AST in endotoxin-induced uveitis (EIU) in rats. In addition, the effect of AST on endotoxin-induced nitric oxide (NO), prostaglandin E2 (PGE2), and tumor necrosis factor (TNF)-alpha production in a mouse macrophage cell line (RAW 264.7) was studied in vitro. METHODS EIU was induced in male Lewis rats by a footpad injection of lipopolysaccharide (LPS). AST or prednisolone was administered intravenously at 30 minutes before, at the same time as, or at 30 minutes after LPS treatment. The number of infiltrating cells and protein concentration in the aqueous humor collected at 24 hours after LPS treatment was determined. RAW 264.7 cells were pretreated with various concentrations of AST for 24 hours and subsequently stimulated with 10 microg/mL of LPS for 24 hours. The levels of PGE2, TNF-alpha, and NO production were determined in vivo and in vitro. RESULTS AST suppressed the development of EIU in a dose-dependent fashion. The anti-inflammatory effect of 100 mg/kg AST was as strong as that of 10 mg/kg prednisolone. AST also decreased production of NO, activity of inducible nitric oxide synthase (NOS), and production of PGE2 and TNF-alpha in RAW264.7 cells in vitro in a dose-dependent manner. CONCLUSIONS This study suggests that AST has a dose-dependent ocular anti-inflammatory effect, by the suppression of NO, PGE2, and TNF-alpha production, through directly blocking NOS enzyme activity.
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Hamazaki T, Sawazaki S, Itomura M, Asaoka E, Nagao Y, Nishimura N, Yazawa K, Kuwamori T, Kobayashi M. The effect of docosahexaenoic acid on aggression in young adults. A placebo-controlled double-blind study. J Clin Invest 1996; 97:1129-33. [PMID: 8613538 PMCID: PMC507162 DOI: 10.1172/jci118507] [Citation(s) in RCA: 177] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
41 students took either docosahexaenoic acid (DHA)-rich oil capsules containing 1.5-1.8 grams DHA/day (17 females and 5 males) or control oil capsules containing 97% soybean oil plus 3% fish oil (12 females and 7 males) for 3 mo in a double-blind fashion. They took a psychological test (P-F Study) and Stroop and dementia-detecting tests at the start and end of the study. The present study started at the end of summer vacation and ended in the middle of mental stress such as final exams. In the control group extraggression (aggression against others) in P-F Study was significantly increased at the end of the study as compared with that measured at the start (delta = +8.9%, P = 0.0022), whereas it was not significantly changed in the DHA group (delta = -1.0%). The 95% CI of differences between the DHA and control groups were -16.8 to -3.0%. DHA supplementation did not affect the Stroop and dementia-detecting tests. Thus, DHA intake prevented extraggression from increasing at times of mental stress. This finding might help understand how fish oils prevent disease like coronary heart disease.
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Yazawa K, Fujimori M, Amano J, Kano Y, Taniguchi S. Bifidobacterium longum as a delivery system for cancer gene therapy: selective localization and growth in hypoxic tumors. Cancer Gene Ther 2000; 7:269-74. [PMID: 10770636 DOI: 10.1038/sj.cgt.7700122] [Citation(s) in RCA: 165] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A fundamental obstacle in gene therapy for cancer is the specific delivery of an anticancer gene product to a solid tumor, and yet no systemic delivery system that specifically targets solid tumors currently exists. A strain of domestic bacteria, Bifidobacterium longum, which is nonpathogenic and anaerobic, selectively localized and proliferated in several types of mouse solid tumors after systemic application. In this report, we further describe a novel approach to cancer gene therapy in which genetically engineered Bifidobacterium is used as a tumor-specific vector. Similarly to wild-type B. longum, genetically engineered B. longum could be detected in tumor tissue only and was not found in a large survey of normal mouse tissues after intravenous injection. This finding strongly suggests that obligate anaerobic bacteria such as Bifidobacterium can be used as highly specific gene delivery vectors for cancer gene therapy.
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MESH Headings
- Animals
- Bifidobacterium/genetics
- Bifidobacterium/growth & development
- Bifidobacterium/metabolism
- Carcinoma, Lewis Lung/genetics
- Carcinoma, Lewis Lung/microbiology
- Carcinoma, Lewis Lung/pathology
- Carcinoma, Lewis Lung/therapy
- Cell Hypoxia/genetics
- Drug Resistance, Microbial
- Genetic Engineering
- Genetic Therapy/methods
- Male
- Melanoma, Experimental/genetics
- Melanoma, Experimental/microbiology
- Melanoma, Experimental/pathology
- Melanoma, Experimental/therapy
- Mice
- Mice, Inbred C57BL
- Spectinomycin/metabolism
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Abstract
A marine bacterium, judged as a new species close to Shewanella putrefaciens, was isolated from the intestinal contents of the Pacific mackerel. The isolated strain SCRC-2378 produced eicosapentaenoic acid (EPA) as the sole polyunsaturated fatty acid, which amounted to 24-40% of the total fatty acid in the cell, which corresponded to 2% of dry cell weight. Under the optimal growth conditions (pH 7.0, 20 degrees C, and grown aerobically for 12-18 h), the yield of SCRC-2738 reached 15 g of dry cells/L or 2 x 10(10) viable cells/mL. EPA existed as phospholipid and was found in the sn-2 position of phosphatidylethanolamine and phosphatidylglycerol. The 38 kbp (1,000 base pairs) genome DNA fragment was cloned from SCRC-2738 and expressed in Escherichia coli, which resulted in the production of EPA. The nucleotide sequence of the 38 kbp DNA fragment was determined. The DNA fragment contains eight open reading frames, and three of them possess homology with enzymes involved in fatty acid synthesis. Thus, it may be possible that these EPA biosynthesis genes are applied for EPA production in yeasts or higher plants, and offer a new method for EPA synthesis as new foods containing EPA.
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Nishijo K, Mori H, Yosikawa K, Yazawa K. Decreased heart rate by acupuncture stimulation in humans via facilitation of cardiac vagal activity and suppression of cardiac sympathetic nerve. Neurosci Lett 1997; 227:165-8. [PMID: 9185676 DOI: 10.1016/s0304-3940(97)00337-6] [Citation(s) in RCA: 144] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The effect of acupuncture stimulation applied to a Ximen point (P4) of a forearm on heart rate was studied in healthy volunteer human subjects. Acupuncture stimulation decreased heart rate, or gave no significant response. The decreased response of heart rate following acupuncture was attenuated by administration of atropine and propranolol. Therefore, the acupuncture-induced response of decrease in heart rate was concluded to be a result of a reciprocal coordination of an increase in cardiac vagal activity and a decrease in cardiac sympathetic activity.
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Shigemori H, Bae MA, Yazawa K, Sasaki T, Kobayashi J. Alteramide A, a new tetracyclic alkaloid from a bacterium Alteromonas sp. associated with the marine sponge Halichondria okadai. J Org Chem 2002. [DOI: 10.1021/jo00041a053] [Citation(s) in RCA: 139] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Yazawa K, Kameyama M. Mechanism of receptor-mediated modulation of the delayed outward potassium current in guinea-pig ventricular myocytes. J Physiol 1990; 421:135-50. [PMID: 2161457 PMCID: PMC1190077 DOI: 10.1113/jphysiol.1990.sp017937] [Citation(s) in RCA: 133] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
1. Receptor-mediated modulation of the delayed outward potassium current (IK) was investigated in guinea-pig single ventricular cells by using whole-cell voltage clamp and intracellular dialysis. 2. Isoprenaline increased IK in a dose-dependent manner with a half-maximum dose of 1.8 X 10(-8) M. Isoprenaline (10(-6) M) maximally increased IK by a factor of 2.85. This effect did not depend on the concentration of intracellular Ca2+ [( Ca2+]i). 3. External application of 10(-5) M-forskolin and internal application of 5 X 10(-5) M-cyclic AMP or 5 X 10(-6) M of the catalytic subunit of cyclic AMP-dependent protein kinase (PKA) also increased IK about 3-fold. The effect of isoprenaline on IK was masked by previous application of cyclic AMP. 4. All the above phosphorylating agents increased the amplitude of IK without a significant change in the current kinetics. 5. In the presence of 10(-5) M-forskolin, an additional application of 10(-8) M-12-O-tetradecanoylphorbol-13-acetate, an activator of protein kinase C (PKC), produced a further increase in IK, suggesting that the active sites of PKA and PKC on the IK channel are different. 6. Acetylcholine (10(-6) M) suppressed IK when the current was previously enhanced by 2 X 10(-8) M-isoprenaline, but had little effect in the absence of isoprenaline. 7. We conclude that beta-adrenergic modulation of IK is mediated by cyclic AMP-dependent phosphorylation but not by an increase in [Ca2+]i, that PKA and PKC enhance IK independently, and that acetylcholine antagonizes beta-adrenergic stimulation of IK most probably by inhibiting adenylate cyclase.
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Wang DW, Yazawa K, Makita N, George AL, Bennett PB. Pharmacological targeting of long QT mutant sodium channels. J Clin Invest 1997; 99:1714-20. [PMID: 9120016 PMCID: PMC507992 DOI: 10.1172/jci119335] [Citation(s) in RCA: 132] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The congenital long QT syndrome (LQTS) is an inherited disorder characterized by a delay in cardiac cellular repolarization leading to cardiac arrhythmias and sudden death often in young people. One form of the disease (LQT3) involves mutations in the voltage-gated cardiac sodium channel. The potential for targeted suppression of the LQT defect was explored by heterologous expression of mutant channels in cultured human cells. Kinetic and steady state analysis revealed an enhanced apparent affinity for the predominantly charged, primary amine compound, mexiletine. The affinity of the mutant channels in the inactivated state was similar to the wild type (WT) channels (IC50 approximately 15-20 microM), but the late-opening channels were inhibited at significantly lower concentrations (IC50 = 2-3 microM) causing a preferential suppression of the late openings. The targeting of the defective behavior of the mutant channels has important implications for therapeutic intervention in this disease. The results provide insights for the selective suppression of the mutant phenotype by very low concentrations of drug and indicate that mexiletine equally suppresses the defect in all three known LQT3 mutants.
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Hashimoto M, Hossain S, Yamasaki H, Yazawa K, Masumura S. Effects of eicosapentaenoic acid and docosahexaenoic acid on plasma membrane fluidity of aortic endothelial cells. Lipids 1999; 34:1297-304. [PMID: 10652989 DOI: 10.1007/s11745-999-0481-6] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We investigated the relative effects of n-3 eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) on the plasma membrane fluidity of endothelial cells (EC) cultured from the thoracic aorta by determining fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) and its cationic derivative trimethylamino-DPH (TMA-DPH). Fluidity assessed by TMA-DPH demonstrated no significant differences in plasma membranes of vehicle (dimethyl sulfoxide; DMSO)-, EPA-, and DHA-treated EC. Plasma membrane fluidity assessed by DPH polarization, however, was significantly higher in the order of DHA > EPA > DMSO. Total cholesterol content decreased significantly by 28.4 and 15.9% in the plasma membranes of DHA- and EPA-treated cells, respectively. Total phospholipid content remained unaltered in the plasma membranes of the three groups of cells; however, the molar ratio of total cholesterol to phospholipid decreased significantly only in the membranes of DHA-treated EC. The unsaturation index in the plasma membranes of EPA- and DHA-treated cells increased by 35.7 and 64.3%, respectively, compared with that in the plasma membranes of control cells. The activities of catalase and glutathione peroxidase in the whole-cell homogenates, and levels of lipid peroxides in either the whole-cell homogenates or in plasma membrane fractions were not altered in EPA- or DHA-treated EC. These results indicate that the influence of DHA is greater than that of EPA in increasing plasma membrane fluidity of vascular EC. We speculate that the greater effect of DHA compared to EPA is due to its greater ability to decrease membrane cholesterol content or the cholesterol/phospholipid molar ratio, or both, and also to its greater ability in elevating the unsaturation index in the plasma membranes of EC.
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Yazawa K, Fujimori M, Nakamura T, Sasaki T, Amano J, Kano Y, Taniguchi S. Bifidobacterium longum as a delivery system for gene therapy of chemically induced rat mammary tumors. Breast Cancer Res Treat 2001; 66:165-70. [PMID: 11437103 DOI: 10.1023/a:1010644217648] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A fundamental obstacle in cancer gene therapy is the specific targeting of therapy directly to a solid tumor, and no systemic delivery system yet exists. A strain of domestic bacteria, Bifidobacterium longum, which is nonpathogenic and anaerobic, selectively localized to and proliferated in 7,12-dimethylbenz[a]anthracene-induced rat mammary tumors after systemic application. We further ascertained the tumor specificity of genetically engineered, as well as wild-type, Bifidobacterium longum. This is the first demonstration that Bifidobacterium longum can be utilized as a specific gene delivery vector for gene therapy on solid breast tumors.
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Ikeuchi M, Koyama T, Takahashi J, Yazawa K. Effects of astaxanthin in obese mice fed a high-fat diet. Biosci Biotechnol Biochem 2007; 71:893-9. [PMID: 17420580 DOI: 10.1271/bbb.60521] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Astaxanthin is a natural antioxidant carotenoid that occurs in a wide variety of living organisms. We investigated the effects of astaxanthin supplementation in obese mice fed a high-fat diet. Astaxanthin inhibited the increases in body weight and weight of adipose tissue that result from feeding a high-fat diet. In addition, astaxanthin reduced liver weight, liver triglyceride, plasma triglyceride, and total cholesterol. These results suggest that astaxanthin might be of value in reducing the likelihood of obesity and metabolic syndrome in affluent societies.
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Journal Article |
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127 |
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Suzuki Y, Ohgami K, Shiratori K, Jin XH, Ilieva I, Koyama Y, Yazawa K, Yoshida K, Kase S, Ohno S. Suppressive effects of astaxanthin against rat endotoxin-induced uveitis by inhibiting the NF-kappaB signaling pathway. Exp Eye Res 2005; 82:275-81. [PMID: 16126197 DOI: 10.1016/j.exer.2005.06.023] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2005] [Revised: 05/27/2005] [Accepted: 06/21/2005] [Indexed: 11/29/2022]
Abstract
We investigated the effects of astaxanthin (AST), a carotenoid, on endotoxin-induced uveitis (EIU), and over the course of the disease measured the expression of inflammatory cytokines and chemokines in the presence or absence of AST. EIU was induced in male Lewis rats by footpad injection of lipopolysaccharide (LPS). The animals were randomly divided to 12 groups with eight animals in each. Immediately after the inoculation, AST (1, 10, or 100 mg kg(-1)) was injected intravenously. Aqueous humour was collected at 6, 12 and 24 hr after LPS inoculation and the number of infiltrating cells in the anterior chamber was counted. In addition, we assayed the concentration of protein, nitric oxide (NO), tumour necrosis factor-alpha (TNF-alpha) and prostaglandin E2 (PGE2). Immunohistochemical staining with a monoclonal antibody against activated NF-kappaB was performed in order to evaluate the effects of AST on NF-kappaB activation. Rats injected with AST showed a significant decrease in the number of infiltrating cells in the anterior chamber and additionally there was a significantly lower concentration of protein, NO, TNF-alpha and PGE2 in the aqueous humour. Moreover, even early stages of EIU were suppressed by injection of AST. The number of activated NF-kappaB-positive cells was lower in iris-ciliary bodies treated with 10 or 100 mg kg(-1) AST at 3 hr after LPS injection. These results suggest that AST reduces ocular inflammation in eyes with EIU by downregulating proinflammatory factors and by inhibiting the NF-kappaB-dependent signaling pathway.
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Research Support, Non-U.S. Gov't |
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109 |
16
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Chou T, Kuramoto M, Otani Y, Shikano M, Yazawa K, Uemura D. Pinnaic acid and tauropinnaic acid: Two novel fatty acids composing a 6-azaspiro[4.5]decane unit from the Okinawan bivalve Pinna muricata. Tetrahedron Lett 1996. [DOI: 10.1016/0040-4039(96)00704-6] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Ikeda I, Cha JY, Yanagita T, Nakatani N, Oogami K, Imaizumi K, Yazawa K. Effects of dietary alpha-linolenic, eicosapentaenoic and docosahexaenoic acids on hepatic lipogenesis and beta-oxidation in rats. Biosci Biotechnol Biochem 1998; 62:675-80. [PMID: 9614698 DOI: 10.1271/bbb.62.675] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The effects of dietary alpha-linolenic, eicosapentaenoic and docosahexaenoic acids on the enzyme activities related to hepatic lipogenesis and beta-oxidation were compared under constant polyunsaturated/monounsaturated/saturated fatty acids and n-6/n-3 ratios of dietary fats in rats. Dietary fat containing linoleic acid as the sole polyunsaturated fatty acid (PUFA) was also given as a control. The concentration of serum triglyceride and phospholipid in the three n-3 PUFA groups was lower than in the linoleic acid group. The hepatic triglyceride concentration was lower and the phospholipid concentration was higher in the three n-3 PUFA groups than in the linoleic acid group. Cytosolic fatty acid synthase (FAS) activity was lower in the n-3 PUFA groups than in the linoleic acid group, the reduction being more predominant in the eicosapentaenoic acid and docosahexaenoic acid groups than in the alpha-linolenic acid group. The cytosolic activities of the NADPH-generating enzymes, glucose-6-phosphate dehydrogenase (G6PDH) and the malic enzyme, were lower in the three n-3 PUFA groups. The activity of carnitine palmitoyltransferase (CPT) in mitochondria was higher only in the eicosapentaenoic acid group than in the other groups. The activity of Mg(2+)-dependent phosphatidate phosphohydrolase (PAP) in microsomes and cytosol was lower in the eicosapentaenoic and docosahexaenoic acid groups than in the linoleic acid group, while there was no effect of dietary fats on the activities of diacylglycerol acyltransferase (DGAT) and glycerol-3-phosphate acyltransferase (G3PAT) in microsomes. The CTP: phosphocholine cytidylyltransferase (CT) activity in the homogenate was lower in the n-3 PUFA groups, the reduction being more prominent in the eicosapentaenoic and docosahexaenoic acid groups than in the alpha-linolenic acid group. The choline kinase (CK) activity in cytosol was lower in the eicosapentaenoic acid group than in the linoleic acid group. These results showed that dietary alpha-linolenic, eicosapentaenoic and docosahexaenoic acids differently influenced hepatic lipogenesis and the partition of fatty acid into oxidation or glycerolipid synthesis.
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Kageyama A, Yazawa K, Ishikawa J, Hotta K, Nishimura K, Mikami Y. Nocardial Infections in Japan from 1992 to 2001, Including the First Report of Infection by Nocardia transvalensis. Eur J Epidemiol 2003; 19:383-9. [PMID: 15180109 DOI: 10.1023/b:ejep.0000024706.02325.c0] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In the period from 1992 to 2001, 303 cases of nocardioses were diagnosed in Japan, with the corresponding etiological agents isolated and characterized. Taxonomic analyses of these 303 strains showed that most nocardial infections were caused by members of the Nocardia asteroides group (72.3%). Speciation showed that 72 strains were N. asteroides, 31 strains were N. cyriacigeorgica, 2 strains were N. beijingensis, 81 strains were N. farcinica, and 33 strains were N. nova. Sixty-six strains of N. brasiliensis were the next most prevalent species of the total Nocardia isolates, followed by 14 strains of N. otitidiscaviarum. Infections by N. transvalensis (3 strains) and N. pseudobrasiliensis (1 strain) were also confirmed. The infections due to N. transvalensis, N. cyriacigeorgica, and N. beijingensis were the first reported in Japan. The most common factor that predisposed individuals to nocardial infection in Japan was therapy by immunosuppressive agents (22.4%), including SLE therapy (3.6%), followed by cancer (6.6%), diabetes (3.6%) and AIDS (2.0%). Nocardial infections occurred more commonly in the elderly, with most of the patients between the ages of 61 and 80 years of age. No significant difference regarding infectivity levels between the sexes was observed.
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Shikano M, Masuzawa Y, Yazawa K, Takayama K, Kudo I, Inoue K. Complete discrimination of docosahexaenoate from arachidonate by 85 kDa cytosolic phospholipase A2 during the hydrolysis of diacyl- and alkenylacylglycerophosphoethanolamine. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1212:211-6. [PMID: 8180247 DOI: 10.1016/0005-2760(94)90255-0] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In our previous report (Shikano, M., Masuzawa, Y. and Yazawa, K. (1993) J. Immunol. 150, 3525-3533), we described that the enrichment of docosahexaenoic acid (DHA, 22:6(n - 3)) reduces both arachidonic acid (AA, 20:4(n - 6)) release and platelet-activating factor (PAF) synthesis in human eosinophilic leukemia cells, Eol-1. Since no DHA release was observed in response to Ca-ionophore stimulation, we presumed that the phospholipase A2 (PLA2) responsible for AA release and PAF synthesis can not hydrolyze the DHA moiety of phospholipids. In the present paper, we examined whether DHA-containing diacyl- and alkenylacylglycerophosphoethanolamine (DHA-diacylGPE and DHA-alkenylacyGPE) are susceptible to the action of AA-preferential 85 kDa cytosolic phospholipase A2 (cPLA2) from rabbit platelets in comparison with AA and eicosapentaenoic acid (EPA, 20:5(n - 3)) derivatives. When diacylGPE was used as a substrate, DHA release was almost negligible under the assay condition that allowed AA and EPA to be liberated at the rates of 4.3 mumol/min per mg protein and 2.5 mumol/min per mg protein, respectively. On the other hand, 14 kDa type II PLA2 hydrolyzed DHA-diacylGPE as well as AA-diacylGPE and EPA-diacylGPE. When DHA-diacylGPE and AA-diacylGPE were mixed at equimolar concentrations, DHA release by cPLA2 was not observed and AA release was reduced to 32% in the case without DHA-diacylGPE. This indicated that DHA-diacylGPE is a poor substrate but possesses the inhibitory activity for cPLA2. cPLA2 does not clearly discriminate between AA-alkenylacylGPE and AA-diacylGPE. As in the case using diacylGPE as a substrate, DHA-alkenylacylGPE was completely discriminated from AA-alkenylacylGPE by cPLA2. The roles of DHA and cPLA2 in the synthesis of lipid mediators will be discussed in relation to the new aspects of the substrate specificity of cPLA2 provided here.
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Okada M, Amamoto T, Tomonaga M, Kawachi A, Yazawa K, Mine K, Fujiwara M. The chronic administration of docosahexaenoic acid reduces the spatial cognitive deficit following transient forebrain ischemia in rats. Neuroscience 1996; 71:17-25. [PMID: 8834389 DOI: 10.1016/0306-4522(95)00427-0] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The purpose of this study was to investigate whether chronic administration of docosahexaenoic acid is able to reduce spatial cognitive deficit following transient ischemia in rats. In addition, we investigated whether the chronic treatment of docosahexaenoic acid is able to protect the hippocampal neuronal damage induced by either hypoxia in vitro or cerebral ischemia in vivo. A chronic administration of 200 mg/kg/day docosahexaenoic acid over 21 days did not affect the content of docosahexaenoic acid in the hippocampus, but did tend to increase it in the frontal cortex. On the other hand, this chronic administration decreased the content of arachidonic acid significantly both in the hippocampus and the frontal cortex. Under hypoxic conditions, the onset of the increase in the NADH fluorescence in the hippocampal slice was made significantly slower relative to the control by the chronic administration of docosahexaenoic acid. Rats were subjected to 10 min of transient forebrain ischemia by the method of four-vessel occlusion and were tested in a radial eight-arm maze task after cerebral reperfusion. Docosahexaenoic acid was administered either once 1 h before occlusion or daily for 21 days before occlusion. The single treatment of docosahexaenoic acid (1, 10, 100 or 200 mg/kg) did not significantly affect any aspect of the spatial learning deficit following occlusion. On the other hand, chronic treatment with docosahexaenoic acid (10, 100 or 200 mg/kg/day) significantly improved the spatial learning deficit following occlusion. A comparison of the neuronal densities in the hippocampal CA1 region of the chronically docosahexaenoic acid-treated (200 mg/kg/day) rats with those of the ischemic control revealed a significant neuronal preservation. From these results, it appears that chronic administration of docosahexaenoic acid may be valuable in ameliorating the spatial cognitive deficit induced by transient forebrain ischemia. In addition, docosahexaenoic acid might contribute to the protection of hippocampal neuronal damage caused by either hypoxia or ischemia.
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Ikeuchi M, Koyama T, Takahashi J, Yazawa K. Effects of Astaxanthin Supplementation on Exercise-Induced Fatigue in Mice. Biol Pharm Bull 2006; 29:2106-10. [PMID: 17015959 DOI: 10.1248/bpb.29.2106] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present study was designed to determine the effect of astaxanthin on endurance capacity in male mice aged 4 weeks. Mice were given orally either vehicle or astaxanthin (1.2, 6, or 30 mg/kg body weight) by stomach intubation for 5 weeks. The astaxanthin group showed a significant increase in swimming time to exhaustion as compared to the control group. Blood lactate concentration in the astaxanthin groups was significantly lower than in the control group. In the control group, plasma non-esterfied fatty acid (NEFA) and plasma glucose were decreased by swimming exercise, but in the astaxanthin group, NEFA and plasma glucose were significantly higher than in the control group. Astaxanthin treatment also significantly decreased fat accumulation. These results suggest that improvement in swimming endurance by the administration of astaxanthin is caused by an increase in utilization of fatty acids as an energy source.
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Oi Y, Hou IC, Fujita H, Yazawa K. Antiobesity effects of Chinese black tea (Pu-erh tea) extract and gallic acid. Phytother Res 2011; 26:475-81. [PMID: 22508359 DOI: 10.1002/ptr.3602] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Revised: 05/27/2011] [Accepted: 05/27/2011] [Indexed: 11/09/2022]
Abstract
The antiobesity effects of Chinese black tea (Pu-erh tea) and of gallic acid (GA) were investigated using in vitro and in vivo assays. Chinese black tea extract (BTE) and GA inhibited pancreatic lipase activity in a dose-dependent manner in vitro; the IC(inhibitory concentration)(50) values were 101.6 and 9.2 µg/mL, respectively. Black tea extract (50, 100 mg/kg body weight (b.w.)) and GA (15, 45 mg/kg b.w.) significantly suppressed the elevation of blood triglyceride after oral administration of a corn oil emulsion (8 mL oil/kg b.w.) to male ddY mice. Moreover, the antiobesity effects of BTE and GA were also evaluated in a mouse model of diet-induced obesity. Female ddY mice were divided into seven groups; normal diet (ND) group, high fat diet (HFD) group, BTE (0.2% and 0.6% of diets) groups, and GA (0.007%, 0.02% and 0.1% of diets) groups; the experimental groups were fed the test diets for 12 weeks. The BTE 0.6% and GA 0.1% groups showed significant suppression of weight gain. The weight of parametrial adipose tissue was strongly correlated with the body weight. These results suggest that GA contributes to the antiobesity effect of BTE as an active constituent by inhibiting pancreatic lipase activity.
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Yazawa K, Kaibara M, Ohara M, Kameyama M. An improved method for isolating cardiac myocytes useful for patch-clamp studies. THE JAPANESE JOURNAL OF PHYSIOLOGY 1990; 40:157-63. [PMID: 2163463 DOI: 10.2170/jjphysiol.40.157] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
An improved method for isolating cardiac myocytes is described. This method consists of the initial dispersion of the myocytes with a new type of collagenase and the following treatment of the cells with a non-specific protease. This method gives more than 80% rod-shaped, viable, and quiescent cells, which are suitable for biochemical as well as electrophysiological experiments. Formation of a G omega seal and subsequent whole-cell recording is easily performed using these cells.
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Ikeda I, Sasaki E, Yasunami H, Nomiyama S, Nakayama M, Sugano M, Imaizumi K, Yazawa K. Digestion and lymphatic transport of eicosapentaenoic and docosahexaenoic acids given in the form of triacylglycerol, free acid and ethyl ester in rats. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1259:297-304. [PMID: 8541338 DOI: 10.1016/0005-2760(95)00180-8] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Lymphatic transport of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids given as trieicosapentaenoyl glycerol (TriEPA) and tridocosahexaenoyl glycerol (TriDHA) was compared with that of ethyl ester and free acid in rats cannulated with thoracic duct. Trioleoylglycerol (TO) served as a control. EPA and DHA, compared with oleic acid, were slowly transported in lymph irrespective of fat types administered. Total 24-h recovery of DHA in all fat types and ethyl EPA was significantly lower compared to that of oleic acid. Lymphatic recovery of EPA and DHA in rats given TriEPA and TriDHA was significantly higher at the first 3 h after the administration compared to those given as free acid or ethyl ester. The recovery in rats given free acid at a later stage (9-24 h) was higher than that of the other fat types. As a result, the 24-h recovery was comparable between triacylglycerol (TAG) and free acid, while it was significantly lower in ethyl ester. Although TriEPA and TriDHA were slowly hydrolyzed by pancreatic lipase in vitro compared with TO and TAGs rich in EPA or DHA at the second position, the hydrolysis rate at 60 min incubation was comparable among the TAGs examined. The hydrolysis rate of ethyl esters was extremely low even in 6 h incubation with lipase. These observations show that presence of EPA and DHA at the 1- and 3-positions of TAGs does not result in their lower recovery in lymph. Processes after lipolysis may be responsible for their low recovery in lymph. In a separate study, slower lymphatic recovery of DHA given as free acid than TriDHA was improved by the simultaneous administration of TO, but not by free oleic acid. The observations suggest that the slow recovery of free acid is caused by delayed TAG synthesis in mucosal cells and/or low micellar solubility of fatty acids in the intestinal lumen due to a limited supply of 2-monoacylglycerol (MAG). A large portion of EPA and DHA were recovered in lymph chylomicrons and very low density lipoproteins (VLDL, > 95%) and incorporated into TAG (84-92%) fraction in all fat types examined. Lymphatic recovery rate of simultaneously administered cholesterol was influenced by the fat types given.
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Arai T, Mikami Y, Fukushima K, Utsumi T, Yazawa K. A new antibiotic, leucinostatin, derived from Penicillium lilacinum. J Antibiot (Tokyo) 1973; 26:157-61. [PMID: 4783199 DOI: 10.7164/antibiotics.26.157] [Citation(s) in RCA: 79] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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