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Biomedical subjects

K Ohtani

Publications and source records attributed to K Ohtani.

At least 181 records · Page 10Linked to original sources
PubMed1992

[Role of p185c-erbB2 in endometrial cancer growth in vitro].

Human endometrial adenocarcinoma cells (Ishikawa line) constitutively express c-erbB2 coded oncoprotein p185erbB2 (p185) which is believed to be an orphan receptor for an unknown growth factor. Since we have shown that expression of p185 in primary lesions of endometrial cancer correlates well with high frequency of lymph node++ metastases and that the metastatic cells in the nodes strongly expressed p185, the role of the oncoprotein in processes of metastases was studied. Culturing the cells in the presence of 15% FCS and with monoclonal antibody to the extracellular domain of p185 (CB-1) inhibited cell growth and attenuated p185 expression on Western blotting, whereas no change occurred with the control antibody. Cells cultured without FCS achieved only approximately 1/3 growth compared to cells with FCS, and further suppression of growth was observed after adding CB-1. When cells were cultured on human term amnion, basement membrane invasion with p185 expression was observed. In nude mice, intraperitoneal seeding resulted in implant formation which was also associated with positive p185 as well as cyclin immunohistochemistry. In the two experiments, treatment of cells with CB-1 inhibited invasion or implant formation. The present study suggests that a signal through p185 receptor molecules acts as a trigger for early proliferation, and interaction with the host may enhance up-regulation of p185.

Adenocarcinoma↗
PubMed1992

[Studies on chemical constituents of the roots of Lantana camara].

Six oligosaccharides (I-VI) and six iridoid glucosides (VII-XII) isolated from the ethanolic extract of Lantana camara roots were identified as stachyose (I), verbascose (II), ajugose (III), verbascotetracose (IV), alpha-D-galac-(1-[-6)-alpha-D-galac(-1](3)-6-D-gluc(V ) , alpha-D-galac-(1-6)-alpha-D-galac(-1]-(4)6-D-)gluc(VI) , theveside (VII), 8-epiloganin (VIII), shanzhsid methyl ester (IX), theviridoside (X), lamiridoside (XI) and geniposide (XII), on the basis of spectral analysis (1H-NMR, 13C-NMR, FD-MS, GC-MS), physico-chemical constants and preparation of derivatives. V and VI were new compounds named lantanose A and lantanose B, respectively. The others were isolated from this plant for the first time.

Drugs, Chinese Herbal↗
PubMed1992

[Stimulatory effects of follicular stimulating hormone on the proliferation of ovarian cancer cell line in vitro and in vivo].

The present study was designed to determine the effects of follicular stimulating hormone (FSH) on the proliferation of the human ovarian cancer cell line (HRA line) in vitro and in vivo. The results showed: 1) The number of cells and 3H-thymidine uptake significantly increased after FSH treatment, but were suppressed by Buserelin (number of cells: 2.5 +/- 0.4 [con] vs 13.8 +/- 1.7 [FSH] vs 3.0 +/- 0.2 [FSH+GnRHa] x 10(4)/ml, uptake: 1,272.0 +/- 51.5 [con] vs 4,183.4 +/- 114.1 [FSH] vs 885.0 +/- 177.0 [FSH+GnRHa]cpm/10(5) variable cell mean +/- SD, p less than 0.05). 2) FSH increased the proportion of the cells in the S phase but decreased the cells in G0/G1 phase (S: 42.1 +/- 0.72 [con] vs 61.7 +/- 0.5 [FSH], G0/G1: 53.8 +/- 0.4 [con] vs 35.5 +/- 0.6 [FSH]% mean +/- SD, p less than 0.01, t-test). 3) Cyclic adenosine monophosphate (cAMP) production by HRA cells was significantly increased by cholera toxin (CTX), but not by FSH (1.29 +/- 0.72 [con] vs 2.05 +/- 0.21 [FSH] vs 16.2 +/- 2.28 [CTX]nM mean +/- SD p less than 0.001), suggesting that FSH has no effects on the adenylate cyclase system in the cell line. 4) FSH and GnRHa receptors were identified in HRA cells, and the number of the receptors was significantly decreased by Buserelin treatment (426.0 +/- 6.8 vs 98.6 +/- 12.3 sites/cell mean +/- SD, p less than 0.05, t-test).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Myoclonic astatic epilepsy presenting eyelid myoclonic seizures induced by closing of eyes.

A male infant with myoclonic astatic epilepsy showed myoclonic seizures of the eyelids by closing of the eyes. There was no photosensitivity in EEG with flash-stimulation and he could induce seizures even in total darkness. The latency between a lid closure and onset of seizure discharges on EEG was relatively long (0.3-0.5 second). Epileptic seizures in this patient may be induced via a brainstem reticular formation, and elevated Bell's position seems to be the necessary stimulus to produce seizures.

Blinking↗
PubMed1991

Molecular cloning and characterization of a novel glycoprotein, gp34, that is specifically induced by the human T-cell leukemia virus type I transactivator p40tax.

We have cloned and sequenced a cDNA encoding gp34, a novel glycoprotein expressed in cells bearing human T-cell leukemia virus type I (HTLV-I). HTLV-I has a trans-acting transcriptional activator, p40tax, that is thought to be implicated in leukemogenesis through the activation of cellular enhancers. With a subline (JPX-9) of the human T-cell line Jurkat, in which p40tax is inducible, gp34 was shown to be of cellular origin and to be transcriptionally activated by p40tax. It was also demonstrated that two species of mRNA are generated from one copy of the gp34 gene and that these mRNAs encode the identical gp34 product and differ in the 3' untranslated region. Analysis of the deduced amino acid sequence of gp34 showed that it lacks typical signal peptides; however, it has a hydrophobic stretch for membrane anchoring and four possible N-linked glycosylation sites at the carboxy-terminal portion, indicating that it belongs to the family of membrane proteins whose carboxy-terminal portion protrudes out of the cell. The gp34 gene displayed relatively delayed induction compared with other genes activated by p40tax. Taken together with the observation of the dependence of gp34 expression on HTLV-I p40tax, unlike other p40tax-dependent genes such as those for the interleukin-2 receptor alpha chain and c-fos, which are expressed or induced under physiological conditions, we predict that the mechanism involved in the induction of gp34 expression by p40tax is distinct from and more intricate than those for the previously characterized genes.

Base Sequence↗
PubMed1991

Studies on Balanites aegyptiaca fruits, an antidiabetic Egyptian folk medicine.

An aqueous extract of mesocarps of the fruits of Balanites aegyptiaca exhibited a prominent antidiabetic activity by oral administration in streptozotocin induced diabetic mice. From one of the active fractions of this extract, two new steroidal saponins were isolated, and their structures were determined as 26-O-beta-D-glucopyranosyl-(25R)-furost-5-ene-3 beta,22,26-triol 3-O-[alpha-L-rhamnopyranosyl-(1----2)]-[beta-D-xylopyranosyl-(1---- 3)]-[alpha-L-rhamnopyranosyl-(1----4)]-beta-D-glucopyranoside and its 22-methyl ether. In addition, two known saponins, 26-O-beta-D-glucopyranosyl-(25R)-furost-5-ene-3 beta,22,26-triol 3-O-(2,4-di-O-alpha-L-rhamnopyranosyl)-beta-D-glucopyranoside and its methyl ether were isolated and identified. It was revealed that the individual saponins did not show antidiabetic activity, while the recombination of these saponins resulted in significant activity. From an ethanolic extract of the epicarps, two known flavonol glycosides, isorhamnetin-3-O-robinobioside and isorhamnetin-3-O-rutinoside were isolated and identified.

Animals↗
PubMed1991

Transfructosylation of rebaudioside A (a sweet glycoside of Stevia leaves) with Microbacterium beta-fructofuranosidase.

It was found that a beta-fructofuranosidase produced by Microbacterium sp. H-1 has potent trans-beta-fructofuranosylation activity from sucrose (donor). By means of this enzyme system, rebaudioside A (RA), the second major sweet steviol glycoside of the leaves of Stevia rebaudiana, was subjected to transfructosylation, affording a mono-beta-fructofuranosylated product (RA-F) in a high yield. The structure of RA-F was elucidated as beta-D-fructofuranosyl-(2----6)-beta-D-glucopyranosyl ester of steviol-13-O-[beta-D-glucopyranosyl-(1----2)]- [beta-D-glucopyranosyl-(1----3)]-beta-D-glucopyranoside. Some improvement in the quality of sweetness was observed for RA-F.

Actinomycetales↗
PubMed1991

Solubilization of steviolbioside and steviolmonoside with gamma-cyclodextrin and its application to selective syntheses of better sweet glycosides from stevioside and rubusoside.

1,4-alpha-Glucosylation at the 13-O-glycosyl moiety of stevioside (S) and rubusoside (RU) results in a significant increase of sweetness. Saponification of the 19-COO-beta-glucosyl linkage of S and RU yielded steviolbioside (SB) (= 13-O-beta-sophorosyl-steviol) and steviolmonoside (SM) (= 13-O-beta-glucosyl-steviol), respectively, both of which are poorly soluble in an acetate buffer. It was found that the solubilities of SM and SB in the buffer solution were remarkably increased in the presence of gamma-cyclodextrin (gamma-CD). SB was solubilized in the buffer solution with the aid of gamma-CD, and the solution was subjected to 1,4-alpha-transglucosylation by using a cyclodextrin glucanotransferase-starch system to give a mixture of products which were glucosylated at the 13-O-glycosyl moiety. This mixture was acetylated, and the acetate was subjected to chemical beta-glucosylation of 19-COOH followed by deacetylation to afford compounds which have superior sweetness to S. In the same way, derivatives with superior sweetness were selectively prepared from RU through SM.

Cyclodextrins↗
PubMed1991

Further study on the 1,4-alpha-transglucosylation of rubusoside, a sweet steviol-bisglucoside from Rubus suavissimus.

Rubusoside (the beta-D-glucosyl ester of 13-O-beta-D-glucosyl-steviol), which is the major sweet principle of leaves of Rubus suavissimus S. Lee, was subjected to 1,4-alpha-transglucosylation by the cyclodextringlucanotransferase-starch system (the CGTase system). The tri- and tetra-glucosylated products were isolated together with the mono- and di-glucosylated products, which had already been isolated. A prominent increase in intensity of the sweetness was observed for the compounds which were di- and tri-glucosylated at the 13-O-glucosyl moiety. This result further substantiated the structure-sweetness relationship for 1,4-alpha-glucosylated compounds of steviol-glycosides reported previously. For protection of the 19-COO-glucosyl moiety against glucosylation by the CGTase system, the 4-hydroxyl group of the 19-COO-glucosyl moiety was beta-galactosylated by the beta-galactosidase-lactose system. This galactosylated compound was subjected to a regio-selective glucosylation of the 13-O-glucosyl moiety by the CGTase system, which was followed by enzymic elimination of the galactosyl group to furnish an exclusive preparation of the improved sweeteners just mentioned.

Carbohydrate Sequence↗
PubMed1991

Enzymic production of sweet stevioside derivatives: transglucosylation by glucosidases.

For the purpose of improving sweetness and a further study on the structure-sweetness relationship of steviol glycosides, transglycosylation of stevioside by a variety of commercial glucosidases was investigated. It was revealed that two alpha-glucosidases gave glucosylated products. Transglucosylation of stevioside by Pullulanase and pullulan exclusively afforded three products, 13-O-[beta-maltotriosyl-(1----2)-beta-D-glucosyl]-19-O-beta-D-g luc osyl- steviol (1), 13-O-[beta-maltosyl-(1----2)-beta-D-glucosyl]-19-O-beta-D-glucosyl- steviol (2) and 13-O-beta-sophorosyl-19-O-beta-maltotriosyl-steviol (3). All of these products have already been obtained by trans-alpha-1,4-glucosylation of stevioside by the cyclodextrin glucanotransferase starch system, and 1 and 2 have been proven to be tasty and potent sweeteners. Transglucosylation of stevioside by Biozyme L and maltose afforded three new products, 4, 5 and 6, the structures of these compounds being elucidated as 13-O-beta-sophorosyl-19-O-beta-isomaltosyl-steviol (4), 13-O-[beta-isomaltosyl(1----2)-beta-D-glucosyl]-19-O-beta-D-glucosyl- steviol (5) and 13-O-[beta-nigerosyl-(1----2)-beta-D-glucosyl]-19-O-beta-D- glucosyl-steviol (6). A significantly high quality of taste was evaluated for 4.

Carbohydrate Sequence↗
PubMed1991

Synergism between two distinct elements of the HTLV-I enhancer during activation by the trans-activator of HTLV-I.

We have conducted functional studies of the enhancer elements of human T-cell leukemia virus type I (HTLV-I) using the human T-cell lines Jurkat and MOLT 4, which are negative for HTLV-I, and MT-2 and TL-Mor, which carry the proviral genome of HTLV-I. Two distinct elements have been implicated in function of the HTLV-I enhancer. One is the 21-base-pair (bp) core element that is responsible for trans-activation by the HTLV-I trans-activator p40tax and that has the ability to bind to cyclic-AMP responsive element binding factor (CREB)-like factor(s). The other is a region interposed between the 21-bp elements. In this study we demonstrate that a subfragment (C26) in the region between the 21-bp elements is involved in trans-activation by p40tax, possibly through binding to an NF-kappa B-like nuclear factor or factors. Formation of the protein-DNA complex with the C26 subfragment was positively affected by p40tax. The C26 element conferred partial responsiveness to p40tax when linked to one copy of the 21-bp element that, by itself, showed little activation in response to p40tax. However, the C26 element alone, even when repeated, could not be activated by p40tax, unlike other NF-kappa B-binding elements. In contrast, the C26 element itself was profoundly activated upon stimulation with 12-O-tetradecanoylphorbol-13-acetate. These findings therefore suggest that the HTLV-I enhancer contains multiple functional elements, including binding sites for at least CREB- and NF-kappa B-like factors, which synergistically cooperate in activation of the HTLV-I enhancer in response to p40tax. Our results also demonstrate that TPA-dependent activation of the HTLV-I enhancer may be mediated through the C26 element.

Base Sequence↗
PubMed1991

[CT findings and prognoses of anoxic brain damage due to near-drowning in children].

We investigated the relationship between serial cranial CT findings and prognoses in 11 children after near-drowning. These patients were rescued after heart arrest for more than 10 minutes and all comatose on admission. CT scans were performed within 2 weeks, at 3 weeks-1 month, 2-4 months and more than 5 months after admission. Characteristics of CT findings and prognoses were classified into four groups. Group 1: low density areas in thalami, basal ganglia and cortical white matters within 2 weeks (three cases; one died, two became vegetative). Group 2: enlargement of the third ventricle at 3 weeks-1 month, and atrophy of pons at 2-4 months (three cases; severe quadriplegia and mental retardation). Group 3: enlargement of the third ventricle at 3 weeks-1 month, but atrophy of pons not observed at 2-4 months (three cases; mild motor disabilities and mild mental retardation). Group 4: enlargement of third ventricle not observed at 3 weeks-1 month (two cases; neither paralysis nor mental retardation).

Child↗
PubMed1990

Wear of artificial denture teeth by use of toothbrushes. Part 1: Abrasive wear of anterior teeth.

High-strength denture teeth (HS teeth) were developed in order to improve the hardness and wear resistance of conventional plastic denture teeth (PL teeth), while retaining their feature of easy occlusal adjustment. The objective of this study was to evaluate the abrasive wear resistance of HS teeth. We conducted wear tests and measured surface roughness using six types of anterior artificial teeth, i.e., three types of HS teeth and three types of PL teeth, the latter serving as the control. The results of the toothbrush abrasion test revealed that the HS teeth had about 5 times greater wear resistance than the PL teeth. It was also found that the type of artificial teeth and the number of abrasive wear-testing strokes had a significant (P less than 0.05) influence on the surface roughness of artificial teeth.

Dental Stress Analysis↗
PubMed1990

IL-2-induced signal transduction: involvement of tyrosine kinase and IL-2 receptor gamma chain.

We previously established a monoclonal antibody, TU11 mAb, which is specific for human IL-2 receptor (IL-2R) beta chain (p75) and does not inhibit IL-2-binding to IL-2R beta. Using TU11 mAb, we first demonstrated the existence of a third component, p64, of IL-2R, tentatively named the gamma chain of IL-2R. TU11 mAb precipitated not only the beta chain but also the alpha and gamma chains in the lysates of cells bearing the high-affinity IL-2R in the presence of IL-2 without any chemical crosslinker. The gamma chain was also detected in lymphoid MOLT alpha beta and MOLT beta cells, which were stably transfected with both alpha and beta cDNA, and with beta cDNA alone, respectively, but not in fibroblastoid COS alpha beta and COS beta cells, which were stably transfected with both alpha and beta cDNA, and with beta cDNA alone, respectively. Furthermore, IL-2-mediated growth signals were transduced in the lymphoid transfectant cells but not in the fibroblastoid transfectant cells, suggesting the possibility that the gamma chain along with the beta chain has an essential role in the transduction of IL-2-mediated growth signals. Using TU11 mAb, we secondly demonstrated that IL-2 rapidly induces tyrosine phosphorylation of both the beta and gamma chains in an IL-2-dose-dependent manner. The tyrosine phosphorylation of beta and gamma chains were also detected in the lymphoid transfectant cells but not in the fibroblastoid transfectant cells, indicating the correlation between tyrosine kinase activation and IL-2-mediated growth signaling. The beta chain was phosphorylated in in vitro on serine, threonine and tyrosine residues, but the gamma chain was phosphorylated in in vitro predominantly on tyrosine residues, suggesting the possibility that the gamma chain itself is a tyrosine kinase molecule.

Enzyme Activation↗