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S Okada

Publications and source records attributed to S Okada.

At least 505 records · Page 28Linked to original sources
PubMed1997

[dl-Camphor Reference Standard (Control 961) of National Institute of Health Sciences].

The raw material of dl-camphor was examined for the preparation of the "dl-Camphor Reference Standard (Control 961)" of National Institute of Health Sciences. Analytical data obtained are as follows: UV spectrum, lambda max = 290 nm; IR spectrum, the same as that of the present JP Camphor Reference Standard (Control 953); melting point, 179.1 degrees C; purity test by gas-chromatography (GC), three kinds of impurities were detected; assay by GC, 99.8%. Based on the above results, the candidate raw material was authorized as the dl-Camphor Reference standard (Control 961) National Institute of Health Sciences (Japanese Pharmacopoeia).

Camphor↗
PubMed1997

[Chlormadinone Acetate Reference Standard (Control 961) of National Institute of Health Sciences].

The raw material for chlormadinone acetate was tested for preparation of the "Chlormadinone Acetate Reference Standard (Control 961)" of National Institute of Health Sciences. Analytical data obtained were as follows: melting point, 215. 3 degrees C; UV spectrum, lambda max = 283.5 nm; IR spectrum, the same as that of JP Chlormadinone Acetate Reference Standard (Control 885); optical rotation, [alpha]20D = -13.0 degrees; thin-layer chromatography, one impurity was detected; high-performance liquid chromatography, two impurities were detected; loss on drying, 0.01%; assay, 99.4% by spectrophotometry and 99.5% by HPLC. Based on the above results, the raw material was authorized as the Chlormadinone Acetate Reference Standard (Control 961) of National Institute of Health Sciences (Japanese Pharmacopoeia).

Chlormadinone Acetate↗
PubMed1997

[Hydrocortisone Acetate Reference Standard (Control 961) of National Institute of Health Sciences].

The raw material of hydrocortisone acetate was tested for the preparation of the "Hydrocortisone Acetate Reference Standard (Control 961)". Analytical data obtained were as follows: IR spectrum, specific absorption wave numbers at 3428, 1748, 1723, 1631, and 1375 cm-1; specific absorbance, E1cm1% (242 nm) = 406; thin-layer chromatography, no impurities were detected until 0.05 microgram; high-performance liquid chromatography (HPLC), 2-3 impurities were detected and the amount of the total impurities was estimated to be about 0.2%; assay by HPLC, 100.7%. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Reference Standard (Control 961).

Hydrocortisone↗
PubMed1997

[Ulinastatin Reference Standard (Control 971) of the National Institute of Health Sciences].

The "Ulinastatin Reference Standard (control 971)" of National Institute of Health Sciences was prepared. The standard material was evaluated in collaboration with one domestic laboratory, and the potency of trypsin inhibiting activity was determined to be 3, 100 units/vial by relative assay method against the Ulinastatin Reference Standard (control 942). Other analytical data obtained were as follows: UV maximum absorption was observed at 277 nm, and the molecular weight was estimated to be about 66,300 by gel filtration method. Maximum variance of material contents in 10 vials was 2.29%. Based on the above results, this standard material was authorized to be the "Ulinastatin Reference Standard (control 971)" of the National Institute of Health Sciences.

Glycoproteins↗
PubMed1997

[Studies on the molecular weight standards for size-exclusion chromatography--standardization of a molecular weight standard for water-soluble polymers].

The possibility of the standardization of molecular weight standards for size-exclusion chromatography (SEC) was investigated in the case of water-soluble polysaccharides such as dextran, hyaluronate and chitosan. In the case of dextran, comparing the method adopted for dextran in EP and BP, it was shown that pullulan, one of commercially available molecular weight standards, can be used in usual SEC method. For hyaluronate and chitosan, applying the Mark-Houwink correction to the calibration curve obtained by pullulan, the acceptable molecular weights could be estimated.

Chitin↗
PubMed1996

Structure of the cyclic glucan produced from amylopectin by Bacillus stearothermophilus branching enzyme.

The thermostable branching enzyme (BE, EC 2.4.1.18) from Bacillus stearothermophilus TRBE14 produces large cyclic glucans from waxy rice amylopectin similar to those obtained from amylose as described elsewhere [H. Takata, T. Takaha, S. Okada. M. Takagi, and T. Imanaka, J. Bacteriol., 178 (1996) 1600-1606]. The structure of the product (P-1) from the late-stage reaction was analyzed in detail. The weight-average degree of polymerization (dpw) of P-1 was 900. Its chain-length distribution was not significantly changed compared with that of amylopectin, although the amount of long chains (dp > 38) was slightly decreased. The cyclic component of P-1, which was isolated by the extensive action of glucoamylase, had dpw of 49. Three point five alpha-1,6 linkages were directly involved in the formation of the ring structure with several non-cyclic side chains linked to the ring. Based on these results, the action and new roles of BE are discussed.

1,4-alpha-Glucan Branching Enzyme↗
PubMed1996

Doppler estimation of pulmonary artery end-diastolic pressure using contrast enhancement of pulmonary regurgitant signals.

Pulmonary artery (PA) end-diastolic pressure is used as an estimate of PA wedge pressure. We evaluated contrast enhanced pulmonary regurgitant signals in the assessment of PA end-diastolic pressure in 24 patients in a critical care unit. Right atrial pressure was estimated by the percent decrease of the inferior vena caval diameter with inspiration. Weak or absent pulmonary regurgitant signals were enhanced by sonicated albumin (Albunex) in 23 patients (96%). The Doppler-determined PA end-diastolic pressure (the sum of the pulmonary regurgitant pressure gradient at end-diastole and the right atrial pressure) was significantly correlated with the catheter-determined PA end-diastolic pressure (y = 0.85x + 1.72, r = 0.93). Compared with invasive hemodynamic monitoring, the contrast-enhanced Doppler technique using Albunex is effective for measuring PA end-diastolic pressure, even in critically ill patients.

Aged↗
PubMed1996

Interactions between Src homology (SH) 2/SH3 adapter proteins and the guanylnucleotide exchange factor SOS are differentially regulated by insulin and epidermal growth factor.

Co-immunoprecipitation of whole cell extracts demonstrated that the guanylnucleotide exchange factor SOS was associated with the small adapter proteins Grb2, CrkII, and Nck. In vitro binding indicated a similar binding affinity of SOS for all three adapter proteins but with a slightly lower Kd for Grb2 (approximately 2.5-fold) compared with Nck and CrkII. Insulin stimulation resulted in co-immunoprecipitation of tyrosine-phosphorylated IRS1 with Grb2 and to a lesser extent CrkII. Although Grb2 also associated with tyrosine-phosphorylated Shc, there was no detectable interaction of CrkII with Shc. In contrast, EGF stimulation resulted in the predominant co-immunoprecipitation of Grb2 with the EGF receptor, whereas CrkII primarily associated with an unidentified 120-130-kDa protein. Similar to the ability of insulin to induce the dissociation of the Grb2-SOS complex, there was a concomitant time-dependent dissociation of the CrkII-SOS and Nck-SOS complexes. However, EGF stimulation had no effect on the association state of the Grb2-SOS or the Nck-SOS complexes but did result in a time-dependent dissociation of the CrkII from SOS. Together, these data demonstrate that different cellular pools of SOS associate with different adapter proteins forming various signaling complexes, each undergoing distinct patterns of assembly/disassembly following growth factor stimulation.

Adaptor Proteins, Signal Transducing↗
PubMed1996

Clinicopathologic features of small pancreatic adenocarcinoma. A collective study.

BACKGROUND: Early diagnosis and complete removal of pancreatic adenocarcinoma (PC) is essential to improve its poor prognosis. It is necessary to find PC when it is small and at an early stage if surgical treatment is to be successful. This is an investigation of the clinicopathologic features of small PC. METHODS: Thirty-one resected and histopathologically examined cases of small PC, 2 cm or less in greatest dimension, were collected from 7 institutions between 1989 and 1994, and their clinicopathologic features were analyzed in detail. RESULTS: Eighteen patients (58.1%) had some symptoms or signs at the time of diagnosis, however, the other 13 (41.9%) had no symptoms. There was no sensitive blood test for the detection of small PC. The detection rates of the pancreatic tumor mass on ultrasonography, endoscopic ultrasonography, and computed tomography were 64.5% (20/31), 73.7% (14/19), and 64.5% (20/31), respectively. Only 13 patients (41.9%) were in International Union Against Cancer (UICC) Stage I, and the other 18 were in Stage III or IV due to lymph node metastasis or peritoneal dissemination. The overall 4-year postoperative survival rate was 54.5% and that of patients in Stage I was 77.9%. CONCLUSIONS: To detect a small PC, a thorough examination may be required in patients with slightly abnormal findings on laboratory tests or imaging modalities, even if the patient is asymptomatic. PC 2 cm or less and belonging to Stage I may be regarded as an early carcinoma, because of its good prognosis.

Adenocarcinoma↗
PubMed1996

Sulphatide binds to human and animal influenza A viruses, and inhibits the viral infection.

We found, by using a virus overlay assay, that influenza A virus isolates bind to sulphatide (HSO3-Gal beta 1-->1'Cer), which has no sialic acid residue, and that the infection of Madin-Darby canine kidney cells with the human influenza virus A/Memphis/1/71 (H3N2) is inhibited by sulphatide. A/Memphis/1/71 (H3N2) causes obvious haemagglutination and low-pH haemolysis of asialoerythrocytes reconstituted with sulphatide. All influenza A virus isolates from the species of animals so far tested bound to sulphatide. The sulphatide-binding specificity of the isolates was different from the viral sialyl-linkage specificity. Influenza A virus isolates also bound to galactosyl ceramide (GalCer; Gal beta 1-->1'Cer), as well as sulphatide, in the virus overlay assays. In contrast, the influenza virus did not bind to N-deacyl, a derivative of sulphatide, glucosyl ceramide or the other neutral glycolipids tested. These results indicate that the linkage of galactose, or sulphated galactose, to ceramide is important for viral binding.

Animals↗
PubMed1996

Ethanol-enhanced permeation of phosphatidylcholine/ phosphatidylethanolamine mixed liposomal membranes due to ethanol-induced lateral phase separation.

Effects of ethanol on permeability of large unilamellar vesicles (ca. 160 nm in diameter), composed of dipalmitoyl phosphatidylcholine/dilauroyl phosphatidylethanolamine (DLPE) mixture, were studied by monitoring leakage of the fluorescent dye, calcein, entrapped in the inner aqueous phase of the vesicles. In the presence of 2.1 M ethanol, permeabilities of membranes in various phases were G (bilayer gel) phase > L (bilayer liquid-crystalline) phase with a high mole fraction of DLPE and (I (ethanol-induced interdigitated gel phase) + G) phase > (I + L) at 20 mol % DLPE. Arrhenius plots of the leakage rate constants demonstrated that the permeability was greater with 2.1 M ethanol than without ethanol, especially in the temperature above 33 degrees C, suggesting that the presence of ethanol can induce lateral phase separation of liposomal membranes and cause them to have a high permeability even if they are stable and have low permeability in its absence.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1996

Insulin and epidermal growth factor receptors regulate distinct pools of Grb2-SOS in the control of Ras activation.

Insulin and epidermal growth factor (EGF) stimulate a rapid but transient increase in the amount of GTP bound to Ras that returns to the basal GDP-bound state within 10-30 min. Although insulin stimulation resulted in a dissociation of the Grb2.SOS complex, EGF did not affect the Grb2.SOS complex but instead induced dissociation of Grb2-SOS from tyrosine-phosphorylated Shc. The dissociation of Grb2-SOS from Shc was not due to dephosphorylation as Shc remained persistently tyrosine-phosphorylated during this time. Furthermore, there was no decrease in the extent of insulin receptor substrate 1, insulin receptor, or EGF receptor tyrosine phosphorylation. Surprisingly, however, despite the EGF-induced decrease in the amount of Grb2-SOS bound to Shc, the extent of Grb2 associated with Shc remained constant, and there was a concomitant increase in the amount of SOS associated with Grb2. In addition, after the insulin-stimulated dissociation of Grb2 from SOS, EGF treatment induced the reassociation of the Grb2.SOS complex. Quantitative immunoprecipitation demonstrated that only a small fraction of the total cellular pool of Grb2 was associated with SOS. Similarly, only a small fraction of SOS and Grb2 were co-immunoprecipitated with Shc. Together, these data suggest the presence of distinct Grb2-SOS pools that are independently utilized by insulin and EGF in their recruitment to tyrosine-phosphorylated Shc.

Adaptor Proteins, Signal Transducing↗
PubMed1996

Controlling substrate preference and transglycosylation activity of neopullulanase by manipulating steric constraint and hydrophobicity in active center.

The substrate specificity and the transglycosylation activity of neopullulanase was altered by site-directed mutagenesis on the basis of information from a three-dimensional structure predicted by computer-aided molecular modeling. According to the predicted three-dimensional structure of the enzyme-substrate complex, it was most likely that Ile-358 affected the substrate preference of the enzyme. Replacing Ile-358 with Trp, which has a bulky side chain, reduced the acceptability of alpha-(1-->6)-branched oligo- and polysaccharides as substrates. The characteristics of the I358W-mutated enzyme were quite different from those of wild-type neopullulanase and rather similar to those of typical starch-saccharifying alpha-amylase. In contrast, replacing Ile-358 with Val, which has a smaller side chain, increased the preference for alpha-(1-->6)-branched oligosaccharides and pullulan as substrates. The transglycosylation activity of neopullulanase appeared to be controlled by manipulating the hydrophobicity around the attacking water molecule, which is most likely used to cleave the glucosidic linkage in the hydrolysis reaction. We predicted three residues, Tyr-377, Met-375, and Ser-422, which were located on the entrance path of the water molecule might be involved. The transglycosylation activity of neopullulanase was increased by replacing one of the three residues with more hydrophobic amino acid residues; Y377F, M375L, and S422V. In contrast, the transglycosylation activity of the enzyme was decreased by replacing Tyr-377 with hydrophilic amino acid residues, Asp or Ser.

Amino Acid Sequence↗
PubMed1996

Increased IL-6-production by cells isolated from the fibrous bone dysplasia tissues in patients with McCune-Albright syndrome.

McCune-Albright syndrome (MAS) is characterized by café-au-lait spot, multiple endocrine hyperfunction, and polyostotic fibrous dysplasia. A somatic point mutation of Gsalpha protein was reported to decrease GTPase activity, leading to increase in the GSalpha-associated hormone actions via cAMP. IL-6 is known to stimulate osteoclast formation and in the IL-6 promoter, a cAMP responsive element has been identified. In this paper, we investigated the role of IL-6 in the bone lesions of MAS, using the isolated fibrous cells from the polyostotic fibrous dysplasia tissues in bones of the two patients with MAS. Bone biopsy specimen revealed the increased osteoclast in number. In both patients, a GSalpha mutation (Arg201 -> His) was identified in the cultured fibrous cells. Intracellular cAMP content and IL-6 secretion by the patient cells were increased. Rp-8Br-cAMP significantly inhibited IL-6 production in the patient cells, while it had no effect on normal control. The addition of dibutyryl cAMP significantly increased the synthesis of IL-6 in normal control cells. In contrast, no effect of dibutyryl cAMP on IL-6 synthesis was observed in the cells from one of the MAS patients. These data suggest that IL-6 is, at least, one of the downstream effectors of cAMP and that the increased IL-6 synthesis has a pathogenic role in the bone lesions of MAS patients via increasing the number of osteoclasts. These results may provide a new strategy for the therapy of MAS patients.

Base Sequence↗
PubMed1996

An additional form of rat Bcl-x, Bcl-xbeta, generated by an unspliced RNA, promotes apoptosis in promyeloid cells.

The bcl-2 oncogene product delays apoptotic cell death and prolongs the cell survival. We cloned two bcl-2-related cDNAs from a rat thymus cDNA library by low stringency hybridization with a rat bcl-2 fragment as a probe. One of these, designated bcl-xalpha, was a counterpart of the human bcl-xL reported previously as a bcl-2-related gene (Boise, L. H., Gonzalez-Garcia, M., Postema, C. E. , Ding, L., Lindsten, T., Turka, L. A., Mao, M., Nunez, G., and Thompson, C. B. (1993) Cell 74, 597-608). The other, designated bcl-xbeta, was novel and found to be generated by an unspliced mRNA, whereas bcl-xalpha was generated from a spliced transcript. The splice junction exactly corresponded to that found in the bcl-2 gene. bcl-xbeta was specifically expressed in cerebellum, heart, and thymus. When bcl-xbeta directed by a strong promoter was introduced into an interleukin-3-dependent promyeloid cell line, FDC-P1, DNA fragmentation was observed even in the growing state in the presence of interleukin-3 although not in the control transfectants. This finding suggests that the rat bcl-xbeta gene product promotes apoptosis in the promyeloid cells.

Animals↗
PubMed1996

Subdomain structure of the matrix attachment region located within the mouse immunoglobulin kappa gene intron.

Using the matrix attachment region (MAR) derived from Ig kappa gene intron, we assessed the importance of internal subregions required for the specific binding to the nuclear matrix. Relative affinities of MAR subfragments were compared in an in vitro binding reaction with isolated matrix. Cleavage at the near-centric MboII site generated two subfragments retaining a significant binding affinity. Dimerization of these subfragments greatly increased the affinity. Only a partial segment (130 bp) of the 3' fragment was necessary to restore the binding. The dimerization effect was lost when the monomer units were separated by nonMAR spacers of 500 bp <. This bipartite organization of Ig kappa MAR could be a general feature of AT-rich MARs, regardless of their genomic locations.

Animals↗