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  • 1
    ISSN: 1573-6881
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Fluorimetric detection ; Tetrahydro-β-carbolines ; β-Carbolines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Reversed-phase ion-pair HPLC with fluorimetric detectors connected in series was studied for the simultaneous determination of two tetrahydro-β-carbolines and two β-carbolines. After additon of internal standards the samples were reacted with fluorescamine, and then subjected to serial extractions to remove their precursor (tryptamine) from the analytical system. This treatment not only suppressed the artefactual formation of tetrahydro-β-carbolines and β-carbolines during analysis, but also effectively purified them. Under optimum conditions, using trifluoroacetic acid as counter ion, all analytes were separated within 14 min and without major interfering peaks. The quantitative ranges were 0.25–80.0 ng mL−1 for both tetrahydro-β-carbolines and 0.1–30.0 ng mL−1 for both β-carbolines. Replicate spiking experiments showed that recovery from most of the samples tested was over 90% and the relative standard deviation ranged from 0.7 to 10.4% within and between assays. The proposed method was applicable to various materials such as soy sauce, vinegar, ketchup, tabasco, beer, wine, sake, whisky, brandy, cows' milk, coffee, cocoa, cheese, cigarette smoke and urine.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-4919
    Keywords: ODC ; PKC ; tumor promotion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract A correlation of the levels of epidermal protein kinase C (PKC) isozymes, steady state levels of ornithine decarboxylase (ODC) mRNA, and ODC antizyme with the induction of ornithine decarboxylase (ODC) activity by a second repeat 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment to mouse skin was determined. A single application of TPA to female CD-1 mouse skin leads to a dramatic induction of ODC activity (≈3 nmol CO2/60 min/mg protein) which peaks at about 5 h after treatment. However, a superinduction of ODC activity (≈13 CO2/60 min/mg protein) is observed upon the second TPA application at 48 or 72 h after the first TPA treatment. Prior application of a tumor initiating dose of 7,12-dimethylbenz[a]anthracine to mouse skin did not influence the degree of induction of ODC by a repeat TPA treatment. Western Blot analyses using antibodies specific to PKC α, β, γ, ɛ and s indicate detectable levels of PKC α, β, δ and ε in mouse epidermal extracts. A time course of the effects of a single topical application of 20 nmol of TPA to the mouse skin indicate that none of PKC isozymes (α, β, γ, δ and ɛ) were completely downregulated at times (72 h) when ODC was overinduced by TPA. TPA-induced steady state levels of ODC mRNA did not correlate with the degree of superinduction of ODC activity by TPA. The second TPA treatment, 72 h after the first TPA treatment, which leads to superinduction of ODC activity did not decrease the levels of the ODC-antizyme. The results indicate that superinduction of mouse epidermal ODC activity is regulated in part post-transcriptionally and may not be the result of either a loss of PKC isoform(s) or a decrease in the levels of ODC antizyme.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary It was shown that the conformation of a single polymer chain in concentrated solutions and in undiluted state can be estimated from the small-angle X-ray scattering of “randomly tagged polymer” mixed in the systems. The randomly tagged polymer means the polymer containing heavy atoms at randomly selected positions along the molecule. The excess scattering of the tagged polymer is obtained by subtracting the scattering of the untagged polymer solution (or bulk) from that of the mixture solution (or bulk) containing the tagged and untagged polymers. The excess scattering obtained in this way contains the contributions of some undesirable “cross terms” of the scattering amplitude. The method for the experimental evaluation of these terms and the conditions under which these terms are negligible are discussed. It was found that the cross terms can be neglected when the contrast in scattering power between the tagged and untagged scattering units is sufficiently large, and the number of the tags per tagged molecule is not so small. The distribution of the tags in the tagged molecules was also taken into consideration. By averaging the theoretical scattered intensity over all possible positions of the tags, it was found that the excess scattering is practically proportional to the scattering function of the untagged polymer when the number of the tags per tagged molecule is not so small. Experimental verification of this theory was shown. It was also shown experimentally that the conformational change, which may be caused by the effect of the tags, can be eliminated by the extrapolation of the results obtained for a series of tagged polymers with various tag contents to zero tag content.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1437-7799
    Keywords: Key words Thin basement membrane disease (TBMD) ; Glomerular basement membrane (GBM) ; tubular basement membrane ; Age
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background. Thin basement membrane disease (TBMD) is a benign hereditary glomerulopathy with a diffuse attenuation of glomerular basement membrane (GBM). Whether the development of renal basement membranes other than GBM is normal in TBMD has not yet been resolved. Methods. We performed a morphometric study to measure the thickness of GBM and proximal tubular basement membrane (P-TBM) in 44 adult patients with TBMD and in 10 adult diseased controls confirmed to have minor glomerular abnormalities. Results. There was a significant difference between the patients with TBMD and the diseased controls in the thickness of the GBM; however, there was no significant difference between the two groups in the thickness of the P-TBM. In the patients with TBMD, the thickness of the GBM was unchanged with age, but the thickness of the P-TBM increased with age, as did that in the diseased controls. Conclusion. Our morphometric study clarified that the development of P-TBM was normal in the patients with TBMD.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-675X
    Keywords: 5-FU ; apoptosis ; bax ; gastric cancer ; p53 ; p21/waf1
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We examined chemosensitivity to 5-fluorouracil (5-FU) in four human gastric cancer cell lines, by analyzing the expression of p53 and its related genes. Treatment with 1mM 5-FU induced variable degrees of apoptosis in the cultured cells. The apoptotic indices 72 h after treatment were approximately 14% in MKN-74 (wild-type p53 gene), 12% in MKN-45 (wild-type), 3% in MKN-28 (mutated) and 0.5% in KATO-III cells (deleted), respectively. On the other hand, 50 μM 5-FU had little effect on the induction of apoptosis in MKN-74 cells, the value being approximately 2% after 72 h. Induction of P53 expression was noted 3 h after initiating the treatment, followed by the induction of P21/Waf1 after 6 h in both MKN-74 and MKN-45 cells. The same expression mode was noted in MKN-74 treated with 50 μM 5-FU. Conversely, the level of P53 expression was constant in MKN-28 cells and absent in KATO-III cells, in which P21/Waf1 had never been induced. The Bax/Bcl-2 expression ratio was gradually elevated for up to 72 h in MKN-74 and MKN-45 cells treated with 1mM 5-FU; in contrast, it was unchanged in MKN-28 and KATO-III cells, and MKN-74 treated with 50 μM 5-FU. These results might indicate that (1) 1mM 5-FU induces apoptosis in cultured gastric cancer cells carrying the wild-type p53 gene, but not those carrying the mutated type or a gene deletion, and (2) the elevated Bax/Bcl-2 expression ratio plays a more crucial role than the higher expression of P21/Waf1 in the induction of p53- gene dependent apoptosis.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-675X
    Keywords: Apoptosis ; Colorectal Carcinoma ; FAS ; p53
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The cell surface Fas antigen transducts an apoptotic signal by its crosslinking with Fas ligand or anti-Fas antibody in a variety of human cultured cells. In this study, we examined the expression of Fas antigen and its mediation of apoptosis in six human colorectal carcinoma cell lines. A flow cytometric analysis revealed that LoVo, DLD-1, WiDr and SW837 cell lines showed higher expression levels of Fas antigen, in contrast to lower expression in COLO201 and COLO320DM. Interferon-γ enhanced the expression of Fas antigen in all of the cell lines examined. Both Fas ligand and Fas-associated phosphatase-1 (FAP-1) were expressed only in COLO320DM. Anti-Fas antibody induced apoptosis in LoVo carrying wild-type p53 gene, but not in the other five cell lines carrying mutated p53 gene. The transfection of wild-type p53 gene using an adenovirous vector upregulated P53 protein in WiDr and SW837 cells, both of which showed, however, no increase in apoptotic cells by anti-Fas antibody treatment. These results indicated that (1) Fas antigen was variably expressed, regardless of the p53 gene status and (2) the susceptibility to anti-Fas antibody-mediated apoptosis did not correlate to Fas, Fas ligand or FAP-1 expression levels. Therefore, we conclude that wild-type P53 expression might not necessarily be essential for Fas-mediated apoptosis in human colorectal carcinoma cell lines.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1437-773X
    Keywords: Key words Bilirubin ; Ferritin ; Hemosiderin ; Lysosomes ; X-Ray microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A patient was first found to have Dubin–Johnson syndrome and chronic hepatitis at the age of 25 years. Two years later, he underwent gastrectomy because of massive bleeding from duodenal ulcer, followed by posttransfusion self-limited biochemical liver damage. Twenty-five years later, his jaundice worsened to a serum bilirubin level of 10 mg/dl. The test for circulating hepatitis C virus RNA was highly positive, and liver histology showed cirrhosis with brown pigment granules in small numbers of hepatocytes. Some pigment granules were positive for histochemical iron stain. Ultrastructural study on the liver showed (1) the presence of iron-specific X-ray-positive pigment granules, and (2) large numbers of myelin-like bodies throughout the hepatocyte cytoplasm. Histologically advanced hepatic lesions of hepatitis C virus infection and posttransfu-sion iron overload may exacerbate bilirubin transport dysfunction of the syndrome.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1572-879X
    Keywords: RT synthesis ; thermal analysis ; NMR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The room-temperature (RT) synthesis of MCM-41 mesoporous compounds with high substitution levels of aluminium (Si / Al = 1.5) is achieved in a minimum time of synthesis. The compound shows similar characteristics to hydrothermally synthesized materials. 27Al NMR study confirms the presence of tetrahedral aluminium in as-synthesized material as well as in the calcined material without observing the presence of octahedral aluminium after calcination.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1572-879X
    Keywords: TS-1 ; competitive oxidation ; 1-and 2-propanol ; 1-methoxy-2-propanol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Oxidation of 2-propanol with hydrogen peroxide catalyzed by TS-1 was strongly retarded in the presence of an equimolar 1-propanol to a level of 1-propanol oxidation, and the competitive oxidation behavior was applied for the selective oxidation of 1-methoxy-2-propanol to afford 1-methoxy-2-propanone in a high yield of 85%.
    Type of Medium: Electronic Resource
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