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Biomedical subjects

M Satake

Publications and source records attributed to M Satake.

At least 163 records · Page 9Linked to original sources
PubMed1995

Structure-activity relationship study of TXA2 receptor antagonists. 4-[2-(4-substituted phenylsulfonylamino)ethylthio]phenoxyacetic acids and related compounds.

We have recently reported that 4-[2-(4-substituted phenylsulfonylamino) ethylthio]phenoxyacetic acids and related compounds showed potent thromboxane A2 (TXA2) receptor antagonist activity. To understand how substituents affect the biological activity, the quantitative structure-activity relationship (QSAR) was analyzed by using the Hansch-Fujita method for 36 compounds, including newly synthesized compounds. The positive coefficient for pi R and FR in the results of the QSAR study suggested that a hydrophobic an sigma electron-withdrawing substituent R at the para-position of the phenylsulfonyl moiety is required to improve the activity. Further, a substituent R which is long and moderately wide, was suggested to be preferable for the activity. The positive coefficients for pi X,Y,W-COOH and sigma Q(1)-(6) may indicate that the introduction of a hydrophobic and electron-withdrawing group on the benzene ring of the phenoxy acetic acid moiety enhances the activity. The length of the W-COOH moiety may also be important. On the other hand, the effect of the presence of methylene (n = 1) was not clear.

Animals↗
PubMed1995

[Segmental muscular atrophy of unilateral upper limb associated with cervical disc herniation in a juvenile male].

A 25-year-old man first noticed atrophy of right upper arm at the age of 15. This symptom progressed for the following 3 years and then became stable. As he noted difficulty in elevating his right arm above the shoulder level, at the age of 25 he was admitted to our hospital. On neurological examination, he had right scapula alata, moderate atrophy and weakness of right triceps muscle. Right triceps reflex was absent. Other neurological examinations were normal. Needle electromyography revealed neurogenic patterns in the muscles of the C5-T1 segments. Cervical MRI and CT myelography revealed mild cervical disc protrusion toward the right side at the C5/6 level and atrophy of the middle and lower cervical cord on the right side, but nothing suggestive of the fexion myelopathy. The clinical manifestations of the patient resembled those of Hirayama disease, except for the distribution of the involved muscles. Since the most severely involved level of the cervical cord (C7 segment) corresponded to the level of the protruded cervical disc, it was suggested that the cervical disc herniation played an important role in the development of the myelopathy in this patient.

Adult↗
PubMed1995

[Glycyrrhitinic acid reference standard (Control 941) of the National Institute of Health Sciences].

The raw material of glycyrrhitinic acid was examined for preparation of the "Glycyrrhitinic Acid Reference Standard". The candidate material was evaluated physico-chemically by a collaborative study in which five laboratories participated. Analytical data obtained were as follows: UV spectrum, lambda max = 251 nm and specific absorbance E1%1cm (EtOH) at the lambda max = 145; IR spectrum, specific absorption numbers were at 1719, 1654, 1216, and 1170 cm-1; thin-layer chromatography, some laboratories detected a trace amount of one spot and others not detected; high-performance liquid chromatography, 2-6 impurities were detected and the amount of any impurities were estimated to be less than 0.2% and the total amount less than 0.5%. Based on the above results, the candidate material was authorized as the Glycyrrhitinic Acid Reference Standard of National Institute of Health Sciences.

Chromatography, High Pressure Liquid↗
PubMed1995

[Berberine hydrochloride reference standard (Control 941) of the National Institute of Health Sciences].

The raw material of berberine hydrochloride was examined for preparation of the "Berberine Hydrochloride Reference Standard". The candidate material was evaluated physico-chemically by a collaborative study in which five laboratories participated. Analytical data obtained were as follows: UV spectrum, lambda max = 228, 263, 345, and 421 nm and specific absorbance E1%1cm at each lambda max = 814, 794, 722, and 160, respectively; IR spectrum, specific absorption wave numbers at 2845, 1633, 1568, and 1506 cm-1; thin-layer chromatography, some laboratories detected a trace amount of one or two spot and others not detected; high-performance liquid chromatography, 2-5 impurities were detected and the amount of any impurities were estimated to be less than 0.05% and the total amount less than 0.2%. Based on the above results, the candidate material was authorized as the Berberine Hydorochloride Reference Standard of National Institute of Health Sciences.

Berberine↗
PubMed1995

[Globalization of herbal medicines].

Herbal medicines, as the major remedy in traditional medical systems, have been used in medical practice and made a great contribution to maintaining human health. WHO is fully aware of the importance of herbal medicines of the health of many people throughout the world, and then WHO reported 3 kinds of guideline for herbal medicines. U.S.A. has the new bill for dietary supplement included herbal medicines, and been discussed the harmonizing North American Herbal Regulation.

Food, Fortified↗
PubMed1994

Growth inhibition and induction of differentiation of t(8;21) acute myeloid leukemia cells by the DNA-binding domain of PEBP2 and the AML1/MTG8(ETO)-specific antisense oligonucleotide.

The translocation from chromosome 8 to chromosome 21, t(8;21), associated with acute myeloid leukemia results in production of an AML1/MTG8(ETO) fusion transcript. The product of the AML1 gene contains an evolutionarily conserved 128-amino acid region referred to as the "Runt domain," which is necessary for binding to DNA at the PEBP2 site. A fragment of the AML1 protein containing mainly the Runt domain and the antisense oligonucleotide complementary to the fusion transcript strongly inhibited the growth and induced differentiation of cell lines derived from acute myeloid leukemia containing t(8;21). These results indicate that the transcriptional regulation through the PEBP2 site is critically important for growth and differentiation of t(8;21) leukemic cells and that the product of the chimeric gene is responsible for the maintenance of the leukemic phenotype.

Acute Disease↗
PubMed1994

Endothelin-A receptor mediates cardiac inhibition by regulating calcium and potassium currents.

Voltage-sensitive ion channels play fundamental roles in the regulation of cardiac function by various neurotransmitters. Endothelins have strong positive inotropic and chronotropic effects, for which recent studies have implicated various intracellular mechanisms. However, very little is known about the underlying ion-channel regulation by the peptide. We report here that endothelin-1 consistently hyperpolarizes the membrane and shortens the duration of the action potential in mammalian atrial myocytes, leading to suppression of electrical excitability of the heart. Endothelin-1, but not endothelin-3, inhibited the L-type calcium current by decreasing cyclic AMP accumulation and activated the muscarinic potassium current by stimulating a pertussis toxin-sensitive GTP-binding protein. Consistent with these results, endothelin-1 strongly reduced the heart rate when it was increased by beta-adrenoceptor stimulation. These effects were blocked by an ETA (endothelin-1-selective) receptor-selective antagonist, BQ123 (refs 8-11). The ETA receptor-mediated regulation of cardiac ion channels gives new insight into our understanding of the physiological and pathophysiological roles of endothelins in the control of cardiac function.

Action Potentials↗
PubMed1994

Glycolipids isolated from Aplysia kurodai can activate cyclic adenosine 3',5'-monophosphate-dependent protein kinase from rat brain.

Cyclic AMP (cAMP)-dependent protein kinase (cAMP-kinase) partially purified from the membrane fractions of rat brains was stimulated by novel phosphonoglycosphingolipids (glycolipids) derived from the skin and nerve fibers of Aplysia kurodai. Among various glycolipids tested, a major glycolipid from the skin, 3-O-MeGal beta 1-->3GalNAc alpha 1-->3[6'-O-(2-aminoethylphosphonyl)Gal alpha 1-->2](2-aminoethylphosphonyl-->6)Glc beta 1-->4Glc beta 1-->1ceramide (SGL-II), was most potent, giving half-maximal activation at 32.2 microM. Activation of cAMP-kinase was maximal with 250 microM SGL-II using kemptide as substrate. The effect of SGL-II was additive on kinase activity at submaximal concentrations of cAMP. The kinase activity activated with SGL-II was inhibited by the addition of protein kinase inhibitor peptide, a specific peptide inhibitor for cAMP-kinase. Its inhibitory pattern was similar to that for the catalytic subunit. Of the various substrates tested, the glycolipid-stimulated cAMP-kinase could phosphorylate microtubule-associated protein 2, synapsin I, and myelin basic protein but not histone H1 and casein. The regulatory subunit strongly inhibited the activity of purified catalytic subunit of cAMP-kinase. This inhibition was reversed by addition of SGL-II, as observed for cAMP. SGL-II was capable of partially dissociating cAMP-kinase, which was observed by gel filtration column chromatography. However, the binding activity of cAMP to the holoenzyme was not inhibited with SGL-II. These results demonstrate that the glycolipids can directly activate cAMP-kinase in a manner similar, but not identical, to that of cAMP.

Animals↗
PubMed1994

PEBP2 alpha B/mouse AML1 consists of multiple isoforms that possess differential transactivation potentials.

A murine transcription factor, PEBP2, is composed of two subunits, alpha and beta. There are two genes in the mouse genome, PEBP2 alpha A and PEBP2 alpha B, which encode the alpha subunit. Two types of the alpha B cDNA clones, alpha B1 and alpha B2, were isolated from mouse fibroblasts and characterized. They were found to represent 3.8- and 7.9-kb transcripts, respectively. The 3.8-kb RNA encodes the previously described alpha B protein referred to as alpha B1, while the 7.9-kb RNA encodes a 387-amino-acid protein, termed alpha B2, which is identical to alpha B1 except that it has an internal deletion of 64 amino acid residues. Both alpha B1 and alpha B2 associate with PEBP2 beta and form a heterodimer. The alpha B2/beta complex binds to the PEBP2 binding site two- to threefold more strongly than the alpha B1/beta complex does. alpha B1 stimulates transcription through the PEBP2 site about 40-fold, while alpha B2 is only about 25 to 45% as active as alpha B1. Transactivation domain is located downstream of the 128-amino-acid runt homology region, referred to as the Runt domain. Mouse chromosome mapping studies revealed that alpha A, alpha B, and beta genes are mapped to chromosomes 17, 16, and 8, respectively. The last two genes are syntenic with the human AML1 on chromosome 21q22 and PEBP2 beta/CBF beta on 16q22 detected at the breakpoints of characteristic chromosome translocations of the two different subtypes of acute myeloid leukemia. These results suggest that previously described chimeric gene products, AML1/MTG8(ETO) and AML1-EAP generated by t(8;21) and t(3;21), respectively, lack the transactivation domain of AML1.

Amino Acid Sequence↗
PubMed1994

Accelerative effect of shikonin, alkannin and acetylshikonin on the proliferation of granulation tissue in rats.

The present study was carried out to compare the accelerative effect of shikonin (R-type), alkannin (S-type), and acetylshikonin on the proliferation of granulation tissue in rats, and to elucidate the correlation between the potency of the effect and their optical activity. Koushikon mainly contained the R-type of acetylshikonin, and Nanshikon mainly contained the S-type of acetylshikonin. Each compound produced a dose-dependent acceleration of the cotton pellet-induced granuloma formation. In comparing identical doses of shikonin, alkannin and acetylshikonin, the potency of their accelerative effects on the proliferation of granulation tissue was about the same. This result suggests that their absolute configurations (R-type or S-type) and their acetylation on the hydroxy group of the sidechain of shikonin or alkannin may not be important in producing the effect.

Animals↗
PubMed1994

Pharmacologically active components from a Peruvian medicinal plant, huira-huira (Culcitium canescens H. & B.).

The methanol extract of Huira-Huira (Culcitium canescens) showed analgesic effects in acetic acid-induced writhing and tail pressure tests, and it also produced potent prolongation of hypnosis induced by pentobarbital. The latter activity was used as an isolation-guide to determine the active components which were identified as dehydrocacalohastine, cacalohastine and cacalonol.

Analgesics↗
PubMed1994

Synthesis and evaluation of novel thiazolidine derivatives as thromboxane A2 receptor antagonists.

A series of 3-benzoyl or 3-phenylsulfonyl-2-substituted thiazolidine derivatives were synthesized, and evaluated for their thromboxane A2 (TXA2) receptor-antagonizing effect on (15S)-15-hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5(Z),13(E)-dienoic acid (U-46619)-induced aggregation of rabbit platelet-rich plasma (PRP). A simple 2-aryl-thiazolidine derivative, 3-benzoyl-2-(4-hydroxy-3-methoxyphenyl)thiazolidine (5a), showed mild TXA2 receptor antagonist activity. Modification of 5a led to 2-chloro-4-[3-(4-chlorophenylsulfonyl)thiazolidin-2-ylmet hyl]phenoxyacetic acid (29d), which showed 10 times more potent TXA2 receptor antagonist activity than 5a.

Animals↗
PubMed1994

Development of pseudolymphoma of liver following interferon-alpha therapy for chronic hepatitis B.

A 42-year-old woman with biopsy-proven chronic hepatitis B, who had been treated with human leukocyte-derived interferon-alpha (huLe-IFN alpha) therapy for two months was found to have liver tumors on routine abdominal ultrasonography examination. She underwent laparotomy, and partial hepatectomy was performed under the clinical diagnosis of hepatocellular carcinoma. The lesions were diagnosed histologically as pseudolymphoma based on the massive infiltration of small mature lymphocytes and the presence of hyperplastic lymph follicles with germinal centers. Immunohistochemistry revealed polyclonal origin of the involved lymphocytes. The possible association between IFN alpha treatment and chronic hepatitis B with the development of pseudolymphoma is discussed.

Adult↗