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S Araki

Publications and source records attributed to S Araki.

At least 37 records · Page 2Linked to original sources
PubMed2001

Capillary zone electrophoretic chiral discrimination using a cationic cyclodextrin derivative: determination of velocity and association constants of each enantiomer of the amino acid derivative with 6-trimethylammonio-deoxy-beta-cyclodextrin.

A positively charged beta-cyclodextrin possessing a trimethylammonio group, 6-trimethylammonio-6-deoxy-beta-cyclodextrin chloride 1 was prepared by the reaction of an amino derivative 3 with methyl iodide under very mild conditions. The cyclodextrin derivative discriminated between enantiomers of acetylphenylalanine 2 on capillary zone electrophoresis (CZE) analysis, which was possibly due to an electrostatic interaction between the trimethylammonio group of 1 and the carboxylate group of 2, and also due to the inclusion of 2 in a hydrophobic molecular cavity of 1. Double data normalization based on relative electrophoretic velocity of peaks due to indirect response of 1 and also water in an injected sample may be effective for elimination of variation and fluctuation of physical parameters of medium, such as viscosity and ionic strength, in order to determine intrinsic association constants and velocity of the complexes.

Amino Acids↗
PubMed2001

Arachidonic acid-induced Ca2+ sensitization of smooth muscle contraction through activation of Rho-kinase.

Arachidonic acid activates isolated Rho-kinase and contracts permeabilized smooth muscle fibres. Various assays were carried out to examine the mechanism of this activation. Native Rho-kinase was activated 5-6 times by arachidonic acid but an N-terminal, constitutively-active fragment of Rho-kinase, expressed as a glutathione-S-transferase (GST) fusion protein and including the catalytic subunit (GST-Rho-kinase-CAT), was not. GST-Rho-kinase-CAT was inhibited by a C-terminal fragment of Rho-kinase and arachidonic acid removed this inhibition. These results suggest that the C-terminal part of Rho-kinase, containing the RhoA binding site and the pleckstrin homology domain, acts as an autoinhibitor. It is suggested further that activation by arachidonic acid is due to its binding to the autoinhibitory region and subsequent release from the catalytic site. Arachidonic acid, at concentrations greater than 30 microM, increases force in alpha-toxin-permeabilized femoral artery but not in Triton X-100-skinned fibres. The content of Rho-kinase in the latter was lower than in alpha-toxin-treated or intact fibres. The arachidonic acid-induced contraction was not observed at a pCa above 8.0 and was inhibited by Y-27632 and wortmannin, inhibitors of Rho-kinase and myosin light-chain kinase (MLCK), respectively. The activation of Rho-kinase and subsequent phosphorylation of the myosin phosphatase target subunit inhibits myosin phosphatase and increases myosin phosphorylation.

Amides↗
PubMed2001

Comparative analyses of the pigment-aggregating and -dispersing actions of MCH on fish chromatophores.

In melanophores of the peppered catfish and the Nile tilapia, melanin-concentrating hormone (MCH) at low doses (<1 microM) induced pigment aggregation, and the aggregated state was maintained in the presence of MCH. However, at higher MCH concentrations (such as 1 and 10 microM), pigment aggregation was immediately followed by some re-dispersion, even in the continued presence of MCH, which led to an apparent decrease in aggregation. This pigment-dispersing activity at higher concentrations of MCH required extracellular Ca(2+) ions. By contrast, medaka melanophores responded to MCH only by pigment aggregation, even at the highest concentration employed (10 microM). Since it is known that medaka melanophores possess specific receptors for alpha-melanophore-stimulating hormone (alpha-MSH), the possibility that interaction between MSH receptors and MCH at high doses in the presence of Ca(2+) might cause pigment dispersion is ruled out. Cyclic MCH analogs, MCH (1-14) and MCH (5-17), failed to induce pigment dispersion, whereas they induced aggregation of melanin granules. These results suggest that another type of MCH receptor that mediates pigment dispersion is present in catfish and tilapia melanophores, and that intact MCH may be the only molecule that can bind to these receptors. Determinations of cAMP content in melanophores, which were isolated from the skin of three fish species and treated with 10 nM or 10 microM MCH, indicate that MCH receptors mediating aggregation may be coupled with Gi protein, whereas MCH receptors that mediate dispersion may be linked to Gs. The response of erythrophores, xanthophores and leucophores to MCH at various concentrations was also examined, and the results suggest that the distribution patterns of the two types of MCH receptors may differ among fish species and among types of chromatophore in the same fish.

Animals↗
PubMed2001

Bayesian value-of-information analysis. An application to a policy model of Alzheimer's disease.

A framework is presented that distinguishes the conceptually separate decisions of which treatment strategy is optimal from the question of whether more information is required to inform this choice in the future. The authors argue that the choice of treatment strategy should be based on expected utility, and the only valid reason to characterize the uncertainty surrounding outcomes of interest is to establish the value of acquiring additional information. A Bayesian decision theoretic approach is demonstrated through a probabilistic analysis of a published policy model of Alzheimer's disease. The expected value of perfect information is estimated for the decision to adopt a new pharmaceutical for the population of patients with Alzheimer's disease in the United States. This provides an upper bound on the value of additional research. The value of information is also estimated for each of the model inputs. This analysis can focus future research by identifying those parameters where more precise estimates would be most valuable and indicating whether an experimental design would be required. We also discuss how this type of analysis can also be used to design experimental research efficiently (identifying optimal sample size and optimal sample allocation) based on the marginal cost and marginal benefit of sample information. Value-of-information analysis can provide a measure of the expected payoff from proposed research, which can be used to set priorities in research and development. It can also inform an efficient regulatory framework for new healthcare technologies: an analysis of the value of information would define when a claim for a new technology should be deemed substantiated and when evidence should be considered competent and reliable when it is not cost-effective to gather any more information.

Alzheimer Disease↗
PubMed2001

A rise of the serum level of von Willebrand factor occurs before clinical manifestation of the severe form of ovarian hyperstimulation syndrome.

BACKGROUND: Ovarian hyperstimulation syndrome (OHSS) appears to be caused by increased capillary permeability in the vascular endothelial cells. Such cells secrete excess amounts of von Willebrand factor (vWF), a large adhesive glycoprotein. METHODS: We retrospectively evaluated the circulating levels of vWF and of vascular endothelial growth factor (VEGF) twice, on the days of oocyte retrieval and embryo transfer, in 46 women who developed early-onset OHSS. RESULTS: Nineteen, 14, and 13 women developed mild, moderate, and severe OHSS, respectively. Inconsistent changes were observed in the VEGF during oocyte retrieval and embryo transfer. However, the net increase in serum vWF during that period showed an increase in absolute value at the time of embryo transfer that paralleled an increase in the severity of OHSS. That is, in mild OHSS, the serum vWF increased from 140 +/- 44 to 164 +/- 28%; in moderate OHSS, it increased from 113 +/- 47 to 186 +/- 22%; and in severe OHSS, it increased from 120 +/- 35 to 274 +/- 63%. All 9 women with a vWF level > 230% at embryo transfer developed severe OHSS, while 9 of 13 women with severe OHSS exhibited a vWF > 230% at embryo transfer. CONCLUSION: The results suggest that a rise of the serum level of vWF occurs prior to clinical manifestation of OHSS in patients with severe OHSS but not in patients with mild OHSS.

Adult↗
PubMed2001

Efficient production of menaquinone (vitamin K2) by a menadione-resistant mutant of Bacillus subtilis.

Efficient production of menaquinone (MK) by Bacillus subtilis was achieved. An edible strain of B. subtilis, isolated from the traditional Japanese food natto, was mutated to improve MK productivity. A menadione-resistant mutant producing 30% more MK than its parent strain was obtained. Soybean extract and glycerol were the best nitrogen and carbon sources, respectively, among the sources tested. Addition of yeast extract also increased MK productivity. The maximum concentration of MK reached about 35.0 mg/l after 4 days of culture in a jar fermenter. The pH of the medium decreased to 5.5 after the start of cultivation, then spontaneously increased to 7.7-8.0. This pH change might be important in the production of MK because only small amounts of MK were obtained when pH was controlled at 5.7, 6.0, 7.0, 7.5 or 8.0.

Bacillus subtilis↗
PubMed2001

Purification, cDNA cloning and characterization of the vascular apoptosis-inducing protein, HV1, from Trimeresurus flavoviridis.

Hemorrhagic snake venom induces apoptosis in vascular endothelial cells (VEC). In previous reports, we described the purification and cDNA cloning from Crotalus atrox of a vascular apoptosis-inducing protein (VAP1) that specifically induces apoptosis in vascular endothelial cells. We report here the purification and cDNA cloning of another vascular apoptosis-inducing protein, HV1, from crude venom of Trimeresurus flavoviridis. The protein, namely HV1, was purified as an inducer of apoptosis in cultured vascular endothelial cells. HV1 was a homodimeric protein with a molecular mass of 110 kDa. HV1 cDNA encoded a protein with 612 amino-acid residues. The amino-acid sequence predicted from the cDNA was highly homologous to VAP1. The amino-acid sequence of HV1 indicated that HV1 belongs to the metalloprotease/disintegrin family, and that it is a multidomain polypeptide with a proprotein domain, a metalloprotease domain, a disintegrin-like domain and a cysteine-rich domain. In the disintegrin-like domain, the sequence DECD, replaces the RGD sequence that has frequently been found in such domains. This replacement also occurs in VAP1. Our results indicate HV1 as the first identified homolog of VAP1.

Amino Acid Sequence↗
PubMed2001

Neurodegenerative features in developmental brain disorders.

The authors examined the occurrence of neurofibrillary tangles (NFT), senile plaques, spheroids in Goll's nucleus, grumose or foamy spheroid bodies (GFSB) in the basal ganglia, and hyaline inclusions in the brainstem nuclei in 62 patients under 40 years of age with non-progressive developmental brain disorders. Five cases had demonstrated NFT, which tended to be confined to the subcortical nuclei, whereas no senile plaques were identified in any case. Spheroids in Goll's nucleus were significantly increased in three cases of congenital brain anomalies and five cases of perinatal hypoxic ischemic encephalopathy. The GFSB-positive subjects were clinicopathologically divided into two subgroups consisting of four cases of congenital malformations, which were also associated with severe respiratory failure, and six cases of perinatal brain disorders in which the basal ganglia were severely affected. Eosinophilic intracytoplasmic inclusions, unlike the hyaline inclusions of the Lewy type, were found in the substantia nigra and/or locus ceruleus in two subjects. It is speculated that a variety of mechanisms, including accelerated aging and anoxic insults, may be involved in the increased occurrence of NFT and/or spheroids in non-progressive developmental disorders. A detailed investigation is useful to clarify the neuronal changes secondary to the brain damages early in development.

Adolescent↗
PubMed2001

The structure of physalin T from Physalis alkekengi var. franchetti.

A new steroidal constituent named physalin T (3) was isolated from the aqueous extract of Physalis alkekengi var. francheti. Based on 1H and 13C NMR spectral studies the structure was assigned as 2,3-dihydrophysalin D, i.e., 5alpha,6beta-dihydroxy-2,3,5,6-tetrahydrophysalin B, which is the first example of a natural physalin possessing a saturated ring A moiety. The structure was confirmed by the chemical transformation from the known physalin D (2) to physalin T.

Antineoplastic Agents, Phytogenic↗
PubMed2001

Oxidative stress and disturbed glutamate transport in hereditary nucleotide repair disorders.

Xeroderma pigmentosum group A (XPA) and Cockayne syndrome (CS) are hereditary DNA repair disorders complicated by progressive neurodegeneration. Here we immunohistochemically examine the in situ expression of materials that are produced by oxidative stress and glutamate transporters (which can contribute to prevention of glutamate neurotoxicity) in the brains of 5 autopsied patients each of XPA, CS, and control groups. All oxidative products, including nitrotyrosine, advanced glycation end product, and 4-hydroxy-2-nonenal-modified protein (HNE) were deposited in large amounts in the globus pallidus of CS patients compared to XPA patients. They were frequently recognized in the pseudocalcified foci and free minerals in the neuropil, and more rarely in foamy spheroids. In addition, the deposition of HNE was observed also in hippocampal and cerebellar dentate neurons of both CS and XPA patients. The expression of glial glutamate transporters, EAAT1 and GLT-1, was affected in the globus pallidus in 5 CS patients and 3 XPA patients. They were also altered in the cerebellar cortex in most of the CS patients. These data suggest that oxidative stress and disturbed glutamate transport may be involved in pallidal and/or cerebellar degeneration in hereditary nucleotide repair disorders.

ATP-Binding Cassette Transporters↗
PubMed2001

Characterization of a novel triphosphonooctaosylceramide from the eggs of the sea hare, Aplysia kurodai.

We have reported the existence of a triphosphonoglycosphingolipid, EGL-I, in the eggs of a sea gastropod, Aplysia kurodai [Yamada, S., Araki, S., Abe, S., Kon, K., Ando, S., and Satake, M. (1995) J. Biochem. 117, 794-799]. We have now isolated a novel glycosphingolipid, named EGL-II, from the eggs of Aplysia. By component analysis, sugar analysis, permethylation studies, fast atom bombardment-mass spectrometry, secondary ion mass spectrometry, and proton magnetic resonance spectrometry, its structure was revealed to be as follows: Galalpha1-->3(GlcNAcalpha1-->2)Galalpha1-->3(3-O-MeGalalpha1-->2)Galalpha1-->3[6'-O-(2-aminoethylphosphonyl)Galalpha1-->2](2-aminoethylphosphonyl-->6)Galbeta1-->4(2-aminoethylphosphonyl-->6)Glcbeta1-->1ceramide. The major aliphatic components of the ceramide are palmitic acid, stearic acid, and anteisononadeca-4-sphingenine.

Animals↗
PubMed2001

G2/M-phase-specific transcription during the plant cell cycle is mediated by c-Myb-like transcription factors.

Plant B-type cyclin genes are expressed specifically in late G2- and M-phases during the cell cycle. Their promoters contain a common cis-acting element, called the MSA (M-specific activator) element, that is necessary and sufficient for periodic promoter activation. This motif also is present in the tobacco kinesin-like protein gene NACK1, which is expressed with timing similar to that of B-type cyclin genes. In this study, we show that G2/M-phase-specific activation of the NACK1 promoter also is regulated by the MSA element, suggesting that a defined set of G2/M-phase-specific genes are coregulated by an MSA-mediated mechanism. In a search for MSA binding factors by yeast one-hybrid screening, we identified three different Myb-like proteins that interact specifically with the MSA sequence. Unlike the majority of plant Myb-like proteins, these Myb proteins, NtmybA1, NtmybA2, and NtmybB, have three imperfect repeats in the DNA binding domain, as in animal c-Myb proteins. During the cell cycle, the level of NtmybB mRNA did not change significantly, whereas the levels of NtmybA1 and A2 mRNAs fluctuated and peaked at M-phase, when B-type cyclin genes were maximally induced. In transient expression assays, NtmybA1 and A2 activated the MSA-containing promoters, whereas NtmybB repressed them. Furthermore, expression of NtmybB repressed the transcriptional activation mediated by NtmybA2. Our data show that a group of plant Myb proteins that are structurally similar to animal c-Myb proteins have unexpected roles in G2/M-phase by modulating the expression of B-type cyclin genes and may regulate a suite of coexpressed genes.

Base Sequence↗
PubMed2001

Effect of high-rate algal ponds on viability of Cryptosporidium parvum oocysts.

The physicochemical conditions of high-rate algal ponds were responsible for a more than 97% reduction in the infectivity of Cryptosporidium parvum oocysts in neonatal mice. The use of semipermeable bags of cellulose showed that pH, ammonia, and/or light seems to be a major factor for the inactivation of oocysts in wastewater, supporting the importance of alga-based systems for safer reuse of treated wastewater.

Animals↗
PubMed2001

Assisted reproductive technologies in conjunction with conservatively treated endometrial adenocarcinoma. A case report.

This case report illustrates the successful use of assisted reproductive technologies (ARTs) in a patient receiving conservative treatment for endometrial adenocarcinoma. A 31-year-old infertile woman, diagnosed as FIGO stage Ia endometrial adenocarcinoma (grade 1), received oral medroxyprogesterone acetate 400 mg/day for 12 weeks. Endometrial curettage was performed and the absence of endometrial carcinoma was confirmed. A single pregnancy was achieved with in vitro fertilization and embryo transfer. A healthy female infant was born via cesarean section at 42 weeks' gestation. The carcinoma has not recurred, and the patient now desires a second child. We conclude that ART combined with progesterone treatment might be a powerful option for the treatment of infertile patients with early stage, well-differentiated endometrial adenocarcinoma.

Adenocarcinoma↗
PubMed2001

Multiple pulmonary emboli with pulmonary hypertension caused by effort thrombosis and effective balloon venoplasty of the subclavian vein.

A 36-year-old woman with effort thrombosis of the subclavian vein associated with multiple pulmonary emboli was successfully treated with local thrombolysis of the subclavian vein using a pulse-spray catheter and systemic anticoagulation. Balloon venoplasty of the residual stenosis of subclavian vein was carried out and in follow-up venography 6 months later, there was no restenosis, and the patient has been asymptomatic for 12 months. Pulmonary embolism is not a rare complication of upper extremity deep vein thrombosis and should be managed as aggressively as lower extremity deep vein thrombosis.

Adult↗
PubMed2001

Production of menaquinone (vitamin K2)-7 by Bacillus subtilis.

Menaquinone-7 (MK-7) is a highly bioactive homologue of vitamin K. We obtained a diphenylamine-resistant mutant strain D200-41 from Bacillus subtilis strain MH-1 which was isolated from fermented soybeans, natto. The mutant strain exhibited decreased production of MK-6. Using strain D200-41, efficient production of MK-7 was achieved. We found that, compared with an agitated and aerated culture, production of MK-7 was increased by static culture. The sporulation of the cells progressed more slowly in a static culture than in an agitated culture. The maximum concentration of MK reached about 60 mg/l in a medium containing 10% soybean extract, 5% glycerol, 0.5% yeast extract and 0.05% K2HPO4 (pH 7.3) when D200-41 cells as well as MH-1 cells were statically cultured at 45 degrees C for 5 d after being cultured with shaking at 37 degrees C for 1 d.

Journal Article↗
PubMed2001

Enhanced phagocytic activity of neutrophils caused by administration of egg white derivatives (EWD) in cats injected with cyclophosphamide (CPA).

To examine in vivo effects of egg white derivatives (EWD), the numbers of peripheral blood cells and neutrophil phagocytosis were evaluated in cats injected intramuscularly with cyclophosphamide (CPA). There were no changes in the number of red blood cells (RBC) or packed cell volume (PCV) values regardless of oral administration of EWD or injection of CPA, but the numbers of platelets, white blood cells (WBC) and neutrophils in cats administered EWD significantly increased (p<0.05 to 0.01) when compared with those in control cats which received saline solution. In addition, the administration of EWD resulted in a significant enhancement in the phagocytic activity of neutrophils (p<0.01) when compared to control cats, suggesting that EWD has a stimulating effect on leukocyte progenitors. The numbers of platelets, WBC and neutrophils, and the phagocytic activity of neutrophils in cats injected with CPA alone were significantly lower (p<0.05 to 0.01) than those in control cats. However, co-administration of EWD to cats injected with CPA resulted in a significant increase in the numbers of platelets, WBC and neutrophils (p<0.05 to 0.01), and in the phagocytic response of neutrophils (p<0.01) when compared to cats injected with CPA alone. Therefore, these results suggest that co-administration of EWD may be effective in reducing some possible side effects in animals treated with immunosuppressive or antitumor agents.

Adjuvants, Immunologic↗