[Growth hormone-binding protein].
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Biomedical subjects
Publications and source records attributed to K Inoue.
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OBJECTIVE: To further probe into the chemical composition of Ilex hainanensis. METHOD: Compound isolation was affected on the basis of the EtOAc soluble fraction of the ethanolic extract from the leaves of the plant. RESULT: Four compounds were obtained and by physico-chemical and spectroscopic methods identified as ursolic acid, ilexgenin A, ilexsaponin A1 and beta-sitosterol-3-O-beta-D-glucoside. CONCLUSION: All the four compounds were isolated from the plant for the first time.
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OBJECTIVE: To establish the pathophysiology of retinoid induced hyperostosis. METHODS: Radiographical, histological, ultrastructural, and immunohistochemical features of retinoid induced hyperostosis were evaluated using C3H-Heston mice and Balb mice. RESULTS: Dose dependent and progressive ossification was noted at extraosseous sites of both mouse strains. New bone formation was seen not only in the extraosseous tissues, but subchondral bone showed prominent proliferation. Major histopathological abnormalities appeared to take place in the chondrocytes near the osteochondral junctions, and some of the metaplastic chondrocytes near the osteochondral junction expressed osteocalcin and type I collagen, extracellular molecules normally present in bone. Species dependent responsiveness was also noted. CONCLUSION: Longterm administration of retinoids may induce an aberrant differentiation of the articular and entheseal chondrocytes near the osteochondral junctions, and the affected cells appeared to produce extracellular components including osteocalcin and type I collagen.
BACKGROUND: Several lines of evidence indicate that abnormalities in brain dopamine and serotonin metabolism may play an important role in bulimia nervosa. However, the regional neurochemical mechanism of the binge eating is poorly understood. Our purpose was to elucidate brain neurochemical mechanisms of binge eating using a rat model. METHODS: The dopamine release and metabolism in the prefrontal cortex (PFC) and in the ventrolateral striatum (VLS) of rats were studied using microdialysis during enhanced rebound hyperphagia induced by space restriction (an animal model of binge eating). RESULTS: The rats showed rebound hyperphagic state when they were released from scheduled feeding (2 hours/day feeding for 7 days). The hyperphagia was further enhanced when they were put in a space-restricted cage where their mobility was restricted. Dopamine release and metabolism were increased both in the PFC and in the VLS during the enhanced rebound hyperphagia. CONCLUSIONS: These results tentatively suggest that increased dopamine release and metabolism in the PFC and in the VLS may be related to space restriction and to activation of motor function involved in feeding behavior, respectively. The enhanced rebound hyperphagia induced by space restriction may be useful as an animal model of binge eating.
A DNA sequence has been obtained for a 35.6-kb genomic segment from Heliobacillus mobilis that contains a major cluster of photosynthesis genes. A total of 30 ORFs were identified, 20 of which encode enzymes for bacteriochlorophyll and carotenoid biosynthesis, reaction-center (RC) apoprotein, and cytochromes for cyclic electron transport. Donor side electron-transfer components to the RC include a putative RC-associated cytochrome c553 and a unique four-large-subunit cytochrome bc complex consisting of Rieske Fe-S protein (encoded by petC), cytochrome b6 (petB), subunit IV (petD), and a diheme cytochrome c (petX). Phylogenetic analysis of various photosynthesis gene products indicates a consistent grouping of oxygenic lineages that are distinct and descendent from anoxygenic lineages. In addition, H. mobilis was placed as the closest relative to cyanobacteria, which form a monophyletic origin to chloroplast-based photosynthetic lineages. The consensus of the photosynthesis gene trees also indicates that purple bacteria are the earliest emerging photosynthetic lineage. Our analysis also indicates that an ancient gene-duplication event giving rise to the paralogous bchI and bchD genes predates the divergence of all photosynthetic groups. In addition, our analysis of gene duplication of the photosystem I and photosystem II core polypeptides supports a "heterologous fusion model" for the origin and evolution of oxygenic photosynthesis.
Serine acetyltransferase (SATase; EC 2.3.1.30), which catalyzes the formation of O-acetyl-L-serine (OAS) from acetyl-CoA and L-serine, plays a regulatory role in the biosynthesis of cysteine by its property of feedback inhibition by cysteine in bacteria and certain plants. Three cDNA clones encoding SATase isoforms (SAT-c, SAT-p, and SAT-m) have been isolated from Arabidopsis thaliana. However, the significance of the feedback regulation has not yet been clear in these different isoforms of SATase from A. thaliana. We constructed the overexpression vectors for cDNAs encoding three SATase isoforms of A. thaliana and analyzed the inhibition of SATase activity by cysteine using the recombinant SATase proteins. In the case of SAT-c, the activity was feedback-inhibited by a low concentration of cysteine (the concentration that inhibits 50% activity; IC50 = 1.8 microM). By contrast, SAT-p and SAT-m were feedback inhibition-insensitive isozymes. We also determined the subcellular localization of three SATase isozymes by the transient expression of fusion proteins of each SATase N-terminal region with jellyfish green fluorescent protein (GFP) in 4-week-old Arabidopsis leaves. The SAT-c-GFP fusion protein was stayed in cytosol, whereas SAT-p-GFP and SAT-m-GFP fusion proteins were localized in chloroplasts and in mitochondria, respectively. These results suggest that these three SATase isoforms, which are localized in the different organelles, are subjected to different feedback regulation, presumably so as to play the particular roles for the production of OAS and cysteine in Arabidopsis cells. Regulatory circuit of cysteine biosynthesis in the plant cells is discussed.
The present study examined changes in the angiotensin type 2 (AT2) receptor mRNA level after carbachol exposure in PC12 cells. The AT2 receptor mRNA level increased 2- to 3-fold after 12-18 h of carbachol exposure (100 microM). The up-regulation of AT2 receptor mRNA was antagonized by atropine, which is a muscarinic receptor antagonist, thus suggesting that the increase in AT2 receptor mRNA is mediated via muscarinic acetylcholine receptors. This increase is blocked by NG-nitro-L-arginine-methylester, nitric oxide (NO) synthase inhibitor, and hemoglobin NO trap. Protein kinase C (PKC) inhibitors, H-7 and calphostin C, inhibited the carbachol-induced upregulation. In addition, a G kinase inhibitor, ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one), inhibited this increase. These findings suggest that the carbachol-induced increases in AT2 receptor mRNA is regulated by the activation of NO-cGMP and/or the PKC pathway.
Vitamin E (alpha-tocopherol) is a fat-soluble antioxidant that is transported by plasma lipoproteins in the body. Alpha-tocopherol transfer protein (alpha-TTP), which was identified as a product of the causative gene for familial isolated vitamin E (FIVE) deficiency, is a cytosolic liver protein which plays an important role in the efficient circulation of plasma vitamin E in the body. In the present study, we detected the message for alpha-TTP at low levels in some rat tissues including brain, spleen, lung and kidney. In the brain, the alpha-TTP transcript was detected predominantly in the cerebellar cortex, as revealed by in situ hybridization histochemistry. In the cerebellar cortex, clusters of the hybridization signal were aligned with the Purkinje cell layer, although the signal was not detected in the Purkinje cells, but in the small cells around the Purkinje cells. This distribution pattern strongly suggests that the message for alpha-TTP is expressed in the Bergmann glial cells. Combined with the previous observation that there was severe Purkinje cell loss in patients with FIVE deficiency, the present data suggest that vitamin E is supplied to the Purkinje cells from the surrounding Bergmann glial cells with the help of alpha-TTP.
The binding of the Myb-like DMP1 transcription factor to DNA consensus sequences [CCCG(G/T)ATGT] in artificial promoters is antagonized by D-type cyclins with no requirement for their catalytic partners, cyclin-dependent kinase (CDK) 4 and CDK6. The subset of DMP1 binding sites containing the GGA core can bind Ets family transcription factors Ets-1 and Ets-2. Screening of a series of natural promoters revealed that the CD13/aminopeptidase N (APN; EC 3.4.11.2) promoter could bind and be activated by DMP1. Activation of CD13/APN required both the intact DNA binding and transactivation domains of DMP1 and was inhibited by D-type cyclins, but not by cyclins A, B, C, or H, in a CDK-independent manner. CD13/APN is transactivated by a cooperative interaction between c-Myb bound to its cognate site and Ets-1 tethered to one of three GGA core-containing sites located 30-50 base pairs downstream. DMP1 binds to one of the Ets binding sites (designated Ets C) and synergizes with c-Myb in activating CD13/APN expression. Analysis of nuclear lysates from KG1a early myeloid cells using an oligonucleotide probe containing only the DMP1/Ets C binding site indicated that endogenous DMP1 and a putative Ets family member bind this element in vivo. DMP1-DNA complexes were significantly more stable than those containing the Ets factor. These data indicate that two different Myb family proteins collaborate in regulating APN gene expression and point to a role for DMP1 in normal myeloid cell development.
Alpha-tocopherol (vitamin E) is an important fat-soluble antioxidant in biological systems and, as a result of scavenging reactive oxygen, it is converted to alpha-tocopherylquinone. Alpha-tocopherol binds to alpha-tocopherol transfer protein (alphaTTP) in the liver cytosol, whereas alpha-tocopherylquinone does not. We found that alpha-tocopherylquinone binds to a liver protein with a molecular mass of about 40 kDa that is distinct from alphaTTP. This alpha-tocopherylquinone binding protein was purified further by multiple-step column chromatography. Sodium dodecylsulfate-polyacrylamide gel electrophoresis of the final preparation yielded a single band with an apparent molecular mass of 25 kDa, which microsequencing revealed was identical to glutathione-S-transferase (GST). The GST activity was inhibited in the presence of alpha-tocopherylquinone, as it is by other non-substrate ligands for GST, confirming that GST and alpha-tocopherylquinone interact directly. Alpha-tocopherylquinone binds to GST and may be transported to the site of metabolism or excreted in the bile as other non-substrate ligands for GST.
Protein biosynthesis is mainly under the control at the level of gene transcription in eukaryotes. Transcription factors are nuclear proteins with abilities to modulate the activity of RNA polymerase II which is responsible for the formation of messenger RNA from double stranded DNA in the cell nuclei. Binding of a radiolabeled oligonucleotide probe for the transcription factor activator protein-1 (AP1) was transiently potentiated 1 to 6 h after the recirculation of blood supply in the thalamus and striatum, but not in the entorhinal cortex, olfactory bulb, frontal cortex, cerebellar cortex and medulla-pons, in gerbils with transient global forebrain ischemia for 5 min, in addition to the hippocampal subregions. The ischemic insult not only increased the immunoreactivity with an antibody against cyclic AMP response element binding protein (CREB) phosphorylated at serine133, but also induced the expression of both c-Jun and c-Fos family proteins 3 h after the recirculation in the thalamus. Limited proteolysis by Staphylococcus aureus (S. aureus) V8 protease revealed the expression of different partner proteins of AP1 in response to ischemic signals in the thalamus. Moreover, ischemia for 2 min led to more prolonged elevation of AP1 binding in the thalamus at least up to 12 h after the reperfusion than that seen with ischemia for 5 min. These results suggest that potentiation of AP1 DNA binding may at least in part involve mechanisms associated with the expression of c-Fos protein through phosphorylation of CREB at serine133 in the thalamus of gerbils with ischemia.
The effects of long-term exposure to ammonia on [Cl-]i in cultured hippocampal neurons were examined. Ammonia increased the [Cl-]i time- (>/=24 h) and concentration- (>/=2 mM) dependently, resulting in a depolarizing shift of the equilibrium potential of the GABAA receptor-Cl- channel opening (EGABA). Such an effect of ammonia was diminished by the inhibitors of Cl-/HCO3- exchangers, 0.1 mM 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS) and 0.1 mM 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), and a carbonic anhydrase inhibitor, 2 mM acetazolamide, but not by a Na+/K+/2Cl-cotransport inhibitor, 50 microM bumetanide, suggesting an enhanced Cl-/HCO3- exchange activity by ammonia. The ammonia-induced increase in [Cl-]i was also abolished by the inhibitors of protein kinase C (PKC), 0.1 microM calphostin C and 10 microM 1-(5-isoquinolinyl-sulfonyl)-2-methylpiperazine dihydrochloride (H-7), and of transcription and de novo protein synthesis, 1 microM actinomycin D and 0.5 microg/ml cycloheximide, while a PKC activator, 0.1 h microM phorbor 12-myristate 13-acetate (PMA), increased the [Cl-]i. The mRNA level of the AE3 Cl-/HCO3- exchanger was increased by ammonia in a calphostin C- and H-7-sensitive manner. The AE3-like immunoreactivity was also increased by ammonia. These findings suggest that long-term exposure to ammonia increases the expression of AE3 through the activation of PKC, resulting in an increase in [Cl-]i in neurons and a reduction of inhibitory postsynaptic potentials.
Although erythropoietin (Epo) has been shown to possess in vitro angiogenic activity, its physiological significance has not been demonstrated. Normally angiogenesis does not occur actively in adults but an exception is the female reproductive organ. In the uterine endometrium, angiogenesis takes place actively for supporting the endometrial growth that occurs during transition from the diestrus to estrous stage. This transition is under control of 17beta-estradiol (E2), an ovarian hormone, and can be mimicked by injection of E2 to ovariectomized (OVX) mouse. Thus, the uterus is a pertinent site to examine the Epo function in angiogenesis. We found that Epo protein and its mRNA were produced in an E2-dependent manner, when the uterus from OVX mouse was cultured in vitro. The de novo protein synthesis was not needed for E2 induction of Epo mRNA. Administration of E2 to OVX mouse induced a rapid and transient increase in Epo mRNA in the uterus. Injection of Epo into the OVX mouse uterine cavity promoted blood vessel formation in the endometrium. Furthermore, injection of the soluble Epo receptor capable of binding with Epo into the uterine cavity of non-OVX mouse in diestrus stage inhibited the endometrial transition to proestrus stage, whereas heat-inactivated soluble Epo receptor allowed the transition to occur. These results, combined with our finding that the endothelial cells in uterine endometrium express Epo receptor, strongly suggest that Epo is an important factor for the E2-dependent cyclical angiogenesis in uterus.
To elucidate the changes in oxidative metabolism in hibernating myocardium after coronary revascularization, we performed myocardial single-photon emission computed tomography with a free fatty acid analog, I-123 beta-methyliodophenylpentadecanoic acid (BMIPP), and thallium-201 before and 1 month after percutaneous transluminal coronary angioplasty (PTCA) in 11 patients with angina pectoris caused by single artery stenosis. All patients had improvement in wall motion after PTCA at the region with coronary stenosis; the wall motion abnormality score evaluated by left ventriculography decreased from 5.5+/-0.8 (mean +/- SE) to 2.1+/-0.9, p <0.01) after PTCA. The defect score of I-123 BMIPP images was significantly larger than that of thallium-201 images either before (14+/-1.3 vs 8.9+/-1.1, p <0.01) or 1 month after (7.4+/-1.5 vs 3.7+/-0.8, p <0.01) PTCA. The decrease in the defect score of both images was significant (p <0.01). Changes in the wall motion abnormality score showed a significant correlation with both the change in the defect score of thallium-201 images (r = 0.58, p < 0.01) and that of I-123 BMIPP images (r = 0.75, p <0.01). These results indicate that the metabolism of free fatty acid is impaired in hibernating myocardium, and that improvement in left ventricular function after successful PTCA is strongly associated with the recovery of oxidative metabolism.
Antioxidants have been proposed to have antiatherogenic potential by their inhibition of low density lipoprotein (LDL) oxidation. Here, we report an antioxidant, BO-653 (2,3-dihydro-5-hydroxy-2, 2-dipentyl-4,6-di-tert-butylbenzofuran), designed to exhibit antioxidative potency comparable to that of alpha-tocopherol, but yet possess a high degree of lipophilicity comparable to that of probucol. BO-653 exhibits a high affinity for LDL and is well distributed in aortic vessels in vivo. In atherosclerosis models of rabbits and mice, BO-653 has been shown to be able to suppress the formation of atherosclerotic lesions without untoward side effects. Specifically, there was no reduction of high density lipoprotein levels. This antioxidant provides additional evidence in support of the oxidized-LDL hypothesis, and itself is a promising candidate antioxidant for clinical use.
We describe a patient with progressive aphemia with agrammatism that was later overlaid with buccofacial apraxia and pseudobulbar palsy. Pathological findings were consistent with those of classic Pick's disease with argyrophilic inclusions and neuronal achromasia, except for restricted cortical atrophy in the frontal operculum posterior to the pars opercularis (Brodmann Area 44). In addition, major neuronal loss was confined to the premotor cortex and the anterior half of the precentral gyrus (Area 6), which apparently explained the aphemia. The present case demonstrated that classic Pick's disease can show quite limited cortical atrophy in a patient who clinically presents with progressive aphemia. Also, our patient differed from the progressive non-fluent aphasia patients reported as having Pick's disease, who were all Pick variants, revealing that classic Pick's disease can be included in the spectrum of progressive aphasia syndrome.
Intracellular recordings were made in a midbrain slice preparation of the rat brain containing the ventral tegmental area (VTA). Dopaminergic principal cells were identified by their electrophysiological properties and their hyperpolarizing responses to dopamine. Superfusion with dopamine (100 microM) caused hyperpolarization and a decrease of the apparent input resistance. By contrast, two structural analogues of ATP, 2-methylthio ATP (2-MeSATP; 10 microM) and alpha,beta-methylene ATP (alpha, beta-meATP; 30 microM) had no effect, when added to the superfusion medium. Pressure applied dopamine also hyperpolarized the membrane, while both 2-MeSATP and alpha,beta-meATP were ineffective. Hence, dopaminergic principal neurons of the VTA do not possess somatic P2 purinoceptors present on peripheral and central noradrenergic neurons.