Biomedical subjects

S Okada

Publications and source records attributed to S Okada.

At least 487 records · Page 27Linked to original sources

PubMed1997

A novel acid phosphatase from Aspergillus niger KU-8 that specifically hydrolyzes C-6 phosphate groups of phosphoryl oligosaccharides.

We had analyzed the detailed structures of the phosphoryl oligosaccharide-1 (PO-1) fraction that was the main component of phosphoryl oligosaccharides (POs) prepared from a potato starch hydrolysate. PO-1 fraction was made up of 3-phosphoryl oligosaccharides and 6-phosphoryl oligosaccharides. Aspergillus niger strain KU-8 produced two types of intracellular acid phosphatase (EC 3.1.3.2, ACPase); ACPase I and II. ACPase II preferentially dephosphorylated 6-phosphoryl oligosaccharides rather than 3-phosphoryl oligosaccharides. The molecular weight of the enzyme was estimated as 66 kDa by SDS-polyacrylamide gel electrophoresis and about 260 kDa by gel filtration, implying the active form to be a tetramer. The optimum pH and temperature of the enzyme were 2.0-2.5 and 60 degrees C, respectively. ACPase II was stable below 50 degrees C for 30 min and pH 2.0-10.0 for 60 min. In spite of the strict specificity toward 6-phosphoryl oligosaccharides in the PO-1 fraction, ACPase II was able to hydrolyze Fru-1,6-di-P, ATP, pyrophosphate, and polyphosphate as well as pNPP and Glc-6-P, a broad substrate specificity.

Acid Phosphatase↗

PubMed1997

Lowering effect of phenolic glycosides on the rise in postprandial glucose in mice.

Glycosides were screened for their lowering effect on the postprandial blood glucose rise in vivo. The effect of phlorizin and other phenolic glycosides on the postprandial blood glucose response to glucose ingestion was evaluated in Std ddY mice. When phlorizin was simultaneously added, the peak blood glucose level was significantly decreased by 51% (p < 0.01) compared to vehicles following glucose ingestion by mice, while the blood insulin responses were generally similar. Screening experiments were conducted with different classes of phenolic glycosides added to a glucose solution. Reductions of 40-52% (p < 0.05) were observed in vehicles containing arbutin, 4-hydroxyphenyl-alpha-D-glucopyranoside (hydroquinone-alpha-glucoside) or glycyrrhizin, and of only 15-31% (not significant) in vehicles containing neohesperidin dihydrochalcone, glycyrrhetinic acid monoglucuronide, or 3,4-dimethoxyphenyl-beta-D-glucopyranoside. No lowering effect was observed in vehicles containing salicin. Since glycyrrhizin, arbutin, and hydroquinone-alpha-glucoside blunted to varying degrees the postprandial blood glucose rise following glucose ingestion, they may be useful adjuvants for the treatment of diabetic subjects.

Animals↗

PubMed1997

Virus neutralizing antibody titer to feline immunodeficiency virus isolates of subtypes A, B and D in experimentally or naturally infected cats.

Six strains of feline immunodeficiency virus (FIV) classified into subtypes A, B and D were examined by cross-neutralization test using Kumi-1 cells (CD4+, CD8+, and CD9+), an interleukin-2 dependent feline T-lymphocyte cell line. Neutralizing activities against these six FIV strains were also investigated in 50 FIV-antibody-positive serum samples collected from different geographical regions in Japan. The cross-neutralization test revealed that antisera against the six strains tended to possess high neutralizing activity against the homologous strain. These antisera were also capable of neutralizing viral strains of the same subtype. However, some of the antisera were broadly crossreactive with all six FIV strains. Serum samples collected from naturally infected cats in the field showed various neutralization patterns for the six FIV strains. These observations reflect the antigenic diversity in FIV strains prevailing in the field. There were also broadly crossreactive serum samples, and 36% (18/50 samples) showed neutralization for all six FIV strains.

Animals↗

PubMed1997

Advanced glycation endproducts stimulate interleukin-6 production by human bone-derived cells.

Advanced glycation endproducts (AGEs), which result from nonenzymatic reactions of glucose with tissue proteins, have been shown to accumulate on long-lived proteins in advanced aging and diabetes mellitus. Thus, AGEs have been implicated in some of the chronic complications associated with these disorders. In this study, we investigated the effects of the glucose-modified protein on the production of the potent bone resorption factors by cells derived from explants of human bone. AGEs stimulated the release of interleukin-6 (IL-6) in the culture supernatants from the bone-derived cells and increased the levels of IL-6 mRNA in the cells. By contrast, the levels of IL-11 in the culture supernatants were not altered by AGEs, and the other bone resorption factors IL-1 alpha and IL-1 beta were undetectable (< 1.0 pg/ml) either without or with the treatment of AGEs. Electrophoretic mobility-shift assays revealed that the transcription nuclear factor-kappa B, which is critical for the inducible expression of IL-6, was activated in the nuclear extracts from mouse osteoblastic MC3T3-E1 cells treated with AGEs. These results suggest that AGEs are involved in bone remodeling modulation by stimulating IL-6 production in human bone-derived cells.

Alkaline Phosphatase↗

PubMed1997

Indomethacin enhances the cytotoxicity of VCR and ADR in human pulmonary adenocarcinoma cells.

The ability of anti-inflammatory agents to modulate cellular sensitivity to anticancer drugs was investigated for pulmonary carcinoma cells in vitro. We examined the drug sensitivity of two pulmonary adenocarcinoma cell lines (76-2, 77-4) in the presence of two drugs, an anticancer drug and an anti-inflammatory agent, for 72 hr by the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay with 96 well plates. Anticancer drugs used for screening test were cyclophosphamide (CPM), mitomycin C (MMC), adriamycin (ADR), 5-fluorouracil (5FU), vindesine (VDS), cisplatin (CDDP), cytarabine (Ara C), methotrexate (MTX), etoposide (VP-16), and vincristine (VCR). Anti-inflammatory agents examined as modulators to anticancer drugs were aspirin, mefenamic acid, ibuprofen, sulindac, piroxicam, phenacetin, dicrofenac, ketoprofen, tolmetin and indomethacin. Screening tests showed indomethacin to be the most effective modulator, resulting in more than a 3-fold increase in cytotoxicity of VCR as compared with that produced by VCR alone. Study of each of the ten anticancer drugs in combination with indomethacin showed VCR to be the most effective anticancer drug in this combination. In 76-2 cells, the concentration of VCR producing 50% growth inhibition (IC50) for VCR alone and VCR in combination with 2 micrograms/ml indomethacin were 1.58 +/- 0.16 and 0.52 +/- 0.1 ng/ml respectively, which represents a 3-fold decrease. In 77-4 cells, the IC50 for VCR alone and VCR in combination with 2 micrograms/ml indomethacin were 2.86 +/- 0.2 and 0.52 +/- 0.11 ng/ml respectively, which represents a 3.8-fold decrease. Our studies indicate that clinically achievable concentrations of indomethacin may be useful in modulating VCR resistance in human pulmonary adenocarcinoma cells, so that combined use of VCR and indomethacin may be of potential clinical significance in the treatment of lung cancer.

Adenocarcinoma↗

PubMed1997

[Uterine cervical carcinoma after radiotherapy: comparison between MR imaging and histopathological findings].

The findings of MRI and pathologic investigation were correlated in curatively irradiated uterine cervical carcinoma. Four patients having residual carcinoma diagnosed by biopsy underwent hysterectomy. MRI demonstrated the mass lesion in one patient with pathologic confirmation of massive viable cancer cells (case I). Of the other three patients, MRI demonstrated normal configuration of the uterine cervix. Cervical signal intensity, however, varied. Hyperintensity was noted in an area of the posterior wall on T2WI in case 2. The anterior wall of the case 2 and the other two cases showed hypointensity. Cervical specimens with normal intensity showed only a small number of degenerated cancer cells. On the other hand, pathologic examination of the posterior wall of the case 2 revealed both cancer cells with varying degrees of degeneration and necrotic tissues. Degeneration of cancer cells was stronger in the superficial layer than the deeper layer. Fibrosis, hemorrhage, granulation and hyalinization were hypointense on T2WI. T2 elongation reflected not only the residual tumor but the post-irradiation changes. Post-irradiated cervix with normal intensity indicated that only a small number of degenerated cancer cells may persist even if the biopsy was positive. We conclude that MRI is useful in evaluating tumor response to radiotherapy.

Carcinoma, Mucoepidermoid↗

PubMed1997

[Diagnostic imaging of "body packers"].

Drug smuggling by intra-abdominal concealment, so called "body packing," has recently increased, even in Japan. Because of fatal drug intoxication and other adverse side effects, it is important to make a radiological diagnosis of body packers as soon as possible. A retrospective analysis of the images of plain abdominal radiography, computed tomography (CT) and ultrasound (US) was performed in twenty-three body packers to evaluate the imaging characteristics of three drugs (cannabis, cocaine and heroin). Cannabis (16 patients) and cocaine (5 patients) packages were demonstrated as well-demarcated rectangular-shaped high-density shadows surrounded by gas halo ("double condom sign") in abdominal plain radiographs and CT. Heroin packages (2 patients) were demonstrated as obscure shadows and were difficult to identify on plain radiographs, because they resembled stool masses. US was performed in one cannabis patient because of the refusal of radiological examination, and packages were demonstrated as round echogenic structures with dorsal echo extinctions. In conclusion, abdominal plain radiography, CT and US represent valuable diagnostic modalities in the assessment of body packers.

Abdomen↗

PubMed1997

Inhibitory effects of Chinese ant extract (CAE) on nephrotoxicity induced by ferric-nitrilotriacetate (Fe-NTA) in Wistar rats.

We observed the inhibitory effects of Chinese ant extract (CAE), a Chinese traditional medicine, on nephrotoxicity induced by Fe-NTA in Wistar rat. Strong positive staining with Schiff's reagent was found in the proximal tubules of the untreated control rats. In contrast, the positivity was very weak in CAE treated rats. The level of TBARS was also higher in the untreated control rats than in CAE treated rats. Meanwhile, the scavenging effect of CAE on hydroxyl radicals was analyzed by electron spin resonance (ESR) in vitro. The results indicate that CAE can efficiently prevent Fe-NTA induced nephrotoxicity through quenching free radicals mechanism.

Animals↗

PubMed1997

[Assessment of cerebral circulation using echo planar imaging--basic analysis in quantitating the mean transit time, cerebral blood flow, and cerebral blood volume].

The mean transit time (MTT), cerebral blood flow (CBF) and cerebral blood volume (CBV) using echo planar imaging (EPI) in 22 aged volunteers were measured based on moment analysis and gamma variate method. The first peak of signal intensity curve (p delta R2.) and the area under the curve after the first peak (AUC) were calculated according to the height over area method, as a convenient quantification. Then, MTT, CBF, and CBV were compared with AUC/p delta R2, p delta R2, and AUC, respectively. There was a good correlation between each other parameter (r = 0.67 - 0.92, every p < 0.001). The slow upward slope and the low peak height, however, caused a larger error between each other parameter.

Blood Flow Velocity↗

PubMed1997

[Assessment of regional microcirculatory changes by EPI perfusion studies in patients with multiple lacunar infarction].

The aim of this report is to assess regional cerebral microcirculatory changes by EPI perfusion study in patients with multiple lacunar infarction(MLI). Especially, we focused on the parameter(rCBV, MTT, rCBF) changes in the white matter and on the relationship between these changes in the gray and white matter. Twenty MLI patients(mean age 72 +/- 15 years) and 10 age-similar normal controls (mean age 65 +/- 12 years) were examined. As a result, the MLI patients demonstrated an insignificant rCBF reduction due to the rCBV elevation in the gray matter and a moderate rCBF reduction with less rCBV elevation in the white matter. These results show a difference in the vascular reserve between the gray and white matter, and insufficiency of the vascular reserve in MLI's white matter.

Aged↗

PubMed1997

A retrospective evaluation of maternal serum screening for the detection of fetal aneuploidy.

A retrospective evaluation of alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and unconjugated oestriol (uE3) levels in maternal blood in the second trimester was conducted for cases of aneuploid pregnancies identified from a series of women who underwent amniocentesis. Blood samples were collected from 1078 women just before genetic amniocentesis was performed, mainly for individuals of advanced maternal age (greater than 35 years). Twenty-five maternal serum samples from pregnant women with an aneuploid fetus, including 14 with Down's syndrome, were available for analysis of all three parameters. An algorithm to detect Down's syndrome was used for this analysis with a risk of > or = 1:299 classified as screen-positive, this being found for 20.4 per cent of the cases (220/1078). The actual Down's syndrome detection rate was 85.7 per cent (12/14), whereas the detection rate for all aneuploidies was 72.0 per cent (18/25). Those that were not detected were two cases of trisomy 21, one trisomy 18, two trisomy 13, three sex chromosome abnormalities, and one case of an additional marker chromosome. The data indicate that this tri-analyte test should be provided after thorough genetic counselling and informed decision-making regarding maternal serum screening for women who wish for a prenatal diagnosis.

Adult↗

PubMed1997

Detection of numerical and structural alterations and fusion of chromosomes 16 and 1 in low-grade papillary breast carcinoma by fluorescence in situ hybridization.

Intracystic papillary breast tumors, including intraductal papilloma and low-grade intracystic papillary carcinoma, constitute a group for which differential diagnosis is frequently difficult. We examined the status of chromosomes 16 and 1 by multicolor fluorescence in situ hybridization (FISH) analyses and the DNA ploidy patterns by flow cytometry in 26 intracystic papillary tumors. Alterations of chromosomes 16 and 1 were detected by FISH in 93 and 85%, respectively, of 14 low-grade papillary carcinomas, and the latter alterations always concurred with the former. Two-color FISH using probes for the D1Z1 (1q12) and D16Z2 (16cen) loci or the D1Z1 and D16Z3 (16q11) loci showed that fusion of chromosomes 16 and 1, mostly with breakpoints distal to 16q11.2 and proximal to 1q12, occurred in 77% of the papillary carcinomas. DNA aneuploidy was detected in 6% of these carcinomas. No papilloma showed these chromosome alterations or DNA aneuploidy. Chromosome 16 and 1 fusions appeared to occur frequently in diploid breast carcinomas and to be involved in the acquisition of a malignant phenotype by duct epithelial cells. We suggest that two-color FISH methods for detecting 1;16 fusions might be applicable as supportive methods for the differential diagnosis of intracystic papillary breast tumors.

Artificial Gene Fusion↗

PubMed1997

[Evaluation of antitumor effect of chemotherapy for pancreatic cancer].

The status of chemotherapy for pancreatic cancer (PC) has been difficult to assess because of the problem of evaluating tumor response, which id dependent on the accurate measurement of tumor size using imaging modalities such as computed tomography. Recently, new assessment methods for chemotherapy in PC, which include clinical benefit response and tumor marker response, have been proposed. The clinical response is evaluated using two parameters; pain and performance status. In our trial of combined chemotherapy with 5-FU and cisplatin in PC patients, 4 (19 %) of 21 PC patients showed remarkable clinical benefit response. With respect to the tumor marker (CA 19-9 and CEA) response, responders, which were defined as patients whose levels were reduced by more than 50% of the pretreatment level, survived significantly longer than non-responders. These new methods may be useful for evaluating chemotherapeutic response and may provide a strong rationale for continuing chemotherapy in patients with stable disease or with non-measurable disease by imaging modalities.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1997

[Analysis of B-3 desamido insulin in human insulin preparations by HPLC].

The content of A-21 desamido insulin (A-21 DI) and B-3 desamido insulin (B-3 DI) in human insulin preparations was measured by new RP-HPLC method using a neutral eluent (pH 6.5). Sometimes the content of B-3 DI in human insulin preparations was about two times larger than that of A-21 DI. In particular, in the case of neutral insulin injection, the content of B-3 DI has increased remarkably as the increase of total desamido content. The content of B-3 DI obtained by the new RP-HPLC method will open the new aspect of the impurity test for insulin preparations.

Chromatography, High Pressure Liquid↗

PubMed1997

[Application of thermogravimetry to loss on drying test and water-content determination of drugs].

Thermogravimetry, one of the techniques of thermal analysis, was applied to the quality control of drug raw materials as a "Loss on Drying" or for "Water Content Determination". Twenty two kinds of drugs were selected for the comparison of the applicability of thermogravimetry with that of Loss on Drying Test and/or Water Content Determination by the Karl-Fisher method. In all kinds of drugs, it was ascertained that the results with thermogravimetry agreed well with those obtained by Loss on Drying test and/or Karl-Fisher method. In conclusion, thermogravimetry can be used as a substitute for the Loss on Drying test in cases where drug possess a water bound strongly. Further, thermogravimetry can be utilized for some drugs to which the Karl-Fisher method cannot be applied due to their insolubility in Karl-Fisher reagents.

Pharmaceutical Preparations↗

PubMed1997

[Epinephrine Bitartrate Reference Standard (Control 951) of National Institute of Health Sciences].

The raw material for epinephrine bitartrate was tested for preparation of the "Epinephrine Bitartrate Reference Standard (Control 951)" of National Institute of Health Sciences. Analytical data obtained were as follows: melting point, 148.6 degrees C (decomposition); UV spectrum, lambda max = 279 nm; IR spectrum, the same as that of JP Epinephrine Bitartrate Reference Standard (Control 792); optical rotation, [alpha]20D = -52.8 degrees; thin-layer chromatography, one impurity was detected; high-performance liquid chromatography, no impurity was detected; loss on drying, 0.01%; assay, 99.6% by potentiometric titration, 100.3% by spectrophotometry. Based on the above results, the raw material was authorized as the Epinephrine Bitartrate Reference Standard (Control 951) of National Institute of Health Sciences (Japanese Pharmacopoeia).

Epinephrine↗

PubMed1997

[Riboflavin Reference Standard (Control 951) of National Institute of Health Sciences].

The raw material for riboflavin was tested for preparation of the "Riboflavin Reference Standard (Control 951)" of National Institute of Health Sciences. Analytical data obtained were as follows: melting point, 284.6 degrees C (decomposition): specific absorbance, E1cm1% = 857 (267 nm), 277 (373 nm), 326 (445 nm); IR spectrum, the same as that of JP Riboflavin Reference Standard (Control 921); optical rotation, [alpha]20D = -135.6 degrees; thin-layer chromatography, three impurities were detected; high-performance liquid chromatography, a small amount of 10 impurities were detected: loss on drying, 0.10%; assay, 100.4% by spectrophotometry. Based on the above results, the raw material was authorized as the Riboflavin Reference Standard (Control 951) of National Institute of Health Sciences (Japanese Pharmacopoeia).

Japan↗

PubMed1997

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

The raw material for estradiol was examined for preparation of the "Estradiol Reference Standard (Control 961)" of National Institute of Health Sciences. Analytical data obtained were as follows: melting point, 179.1 degrees C; UV spectrum, lambda max = 281 nm; IR spectrum, the same as that of the Estradiol Reference Standard of National Institute of Health Sciences (Control 931); optical rotation, [alpha]20D = +79.5 degrees; thin-layer chromatography, one impurity was detected; high-performance liquid chromatography (HPLC), a trace amount of three impurities were detected; loss on drying, 3.17%; assay, 99.4% by UV spectrophotometry and 99.0% by HPLC. Based on the above results, the raw material was authorized as the Estradiol Reference Standard (Control 961) of National Institute of Health Sciences.

Estradiol↗