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14 záznamů v Medvik Filtry

Kniha

Evaluation of certain contaminants in food : seventy-second report of the Joint FAO/WHO Expert Committee on Food Additives

Joint FAO/WHO Expert Committee on Food Additives. Meeting (72. : 2010 : Řím, Itálie)
Autor Autorita

Geneva : World Health Organization, 2011

WHO technical report series, ISSN 0512-3054 ; 959

viii, 105 s. : tab. ; 24 cm

Kapitola

Obezita v dospělosti - Etiologické determinanty obezity v dospělosti : životní styl, životní prostředí, biologické a farmakologické činitele

Müllerová, Dana, 1962-
Autor Autorita ORCID Ústav hygieny LF UK a I. intererní klinika LF UK a FN Plzeň

Obezita - prevence a léčba. 2009 ; () : 121-126.

ISBN 978-80-204-2146-3
Medvik
Zdroj

Článek

Synthesis, characterization and biological activity of ring-substituted 6-benzylamino-9-tetrahydropyran-2-yl and 9-tetrahydrofuran-2-ylpurine derivatives

Bioorganic & medicinal chemistry. 2009 ; 17 (5) : 1938-1947.

Bioorg Med Chem
Medvik
Zdroj

In an attempt to improve specific biological functions of cytokinins routinely used in plant micropropagation, 33 6-benzylamino-9-tetrahydropyran-2-ylpurine (THPP) and 9-tetrahydrofuran-2-ylpurine (THFP) derivatives, with variously positioned hydroxy and methoxy functional groups on the benzyl ring, were prepared. The new derivatives were prepared by condensation of 6-chloropurine with 3,4-dihydro-2H-pyran or 2,3-dihydrofuran and then by the condensation of these intermediates with the corresponding benzylamines. The prepared compounds were characterized by elemental analyses, TLC, HPLC, melting point determinations, CI+ MS and (1)H NMR spectroscopy. The cytokinin activity of all the prepared derivatives was assessed in three classical cytokinin bioassays (tobacco callus, wheat leaf senescence and Amaranthus bioassay). The derivatives 6-(3-hydroxybenzylamino)-9-tetrahydropyran-2-ylpurine (3) and 6-(3-hydroxybenzylamino)-9-tetrahydrofuran-2-ylpurine (23) were selected, because of the high affinity of their parent compound meta-topolin (mT, 6-(3-hydroxybenzylamino)purine) to cytokinin receptors, as model compounds for studying their perception by the receptors CRE1/AHK4 and AHK3 in a bacterial assay. Both receptors perceived these two derivatives less well than they perceived the parent compound. Subsequently, the susceptibility of several new derivatives to enzyme degradation by cytokinin oxidase/dehydrogenase was studied. Substitution of tetrahydropyran-2-yl (THP) at the N(9) position decreased the turnover rates of all new derivatives to some extent. To provide a practical perspective, the cytotoxicity of the prepared compounds against human diploid fibroblasts (BJ) and the human cancer cell lines K-562 and MCF-7 was also assayed in vitro. The prepared compounds showed none or marginal cytotoxicity compared to the corresponding N(9)-ribosides. Finally, the pH stability of the two model compounds was assessed in acidic and neutral water solutions (pH 3-7) by high-performance liquid chromatography (HPLC).

MeSH
cytokininy chemie metabolismus MeSH
fibroblasty účinky léků MeSH
financování organizované MeSH
furany chemická syntéza chemie toxicita MeSH
kinetika MeSH
koncentrace vodíkových iontů MeSH
lidé MeSH
nádorové buněčné linie MeSH
puriny chemická syntéza chemie toxicita MeSH
pyrany chemická syntéza chemie toxicita MeSH
stabilita léku MeSH
Check Tag
lidé MeSH

Abstrakt

Health risk of breasst-fed infants of ochratoxin "A" [Riziká ohrozenia zdravia dojčeného dieťaťa ochratoxínom "A"]

School and health 21. (2). 2007 ; (2) : 861-864.

ISBN 978-80-7315-138-6
Medvik
Zdroj

Klíčová slova
Ochratoxin A,
MeSH
dioxiny škodlivé účinky toxicita MeSH
dítě MeSH
furany izolace a purifikace škodlivé účinky toxicita MeSH
hodnocení stavu výživy MeSH
kojenec MeSH
kojení * MeSH
lidé MeSH
mateřské mléko * MeSH
mykotoxiny izolace a purifikace škodlivé účinky toxicita MeSH
ochratoxiny izolace a purifikace škodlivé účinky toxicita MeSH
pesticidy izolace a purifikace škodlivé účinky toxicita MeSH
rozpouštědla izolace a purifikace škodlivé účinky toxicita MeSH
xenobiotika * izolace a purifikace metabolismus škodlivé účinky MeSH
Check Tag
dítě MeSH
kojenec MeSH
lidé MeSH

Článek

Interference of contaminated sediment extracts and environmental pollutants with retinoid signaling

Environmental toxicology and chemistry. 2007 ; 26 (8) : 1591-1599.

Environmental Toxicology & Chemistry
ISSN 0730-7268
Medvik
Zdroj

Retinoids are known to regulate important processes such as differentiation, development, and embryogenesis. Some effects, such as malformations in frogs or changes in metabolism of birds, could be related to disruption of the retinoid signaling pathway by exposure to organic contaminants. A new reporter gene assay has been established for evaluation of the modulation of retinoid signaling by individual chemicals or environmental samples. The bioassay is based on the pluripotent embryonic carcinoma cell line P19 stably transfected with the firefly luciferase gene under the control of a retinoic acid-responsive element (clone P19/ A15). The cell line was used to characterize the effects of individual chemicals and sediments extracts on retinoid signaling pathways. The extracts of sediments from the River Kymi, Finland, which contained polychlorinated dioxins and furans and polycyclic aromatic hydrocarbons (PAHs), significantly increased the potency of all-trans retinoic acid (ATRA), while no effect was observed with the extract of the sediment from reference locality. Considerable part of the effect was caused by the labile fraction of the sediment extracts. Also, several individual PAHs potentiated the effect of ATRA; on the other hand, 2,3,7,8-tetrachlorodibenzo-p-dioxin and several phthalates showed slightly inhibiting effect. These results suggest that PAHs could be able to modulate the retinoid signaling pathway and that they could be responsible for a part of the proretinoid activity observed in the sediment extracts. However, the effects of PAHs on the retinoic acid signaling pathways do not seem to be mediated directly by crosstalk with aryl hydrocarbon receptor.