نتایج جستجو برای: 22r
تعداد نتایج: 227 فیلتر نتایج به سال:
Gas chromatography±mass spectrometry (GC±MS) and GC±MS±MS analyses of heavy oils from Bolivar Coastal Fields (Lagunillas Field) show a complete set of demethylated tricyclic terpanes. As is the case for the 25-norhopanes, the demethylated tricyclics are probably formed in reservoirs by microbially-mediated removal of the methyl group from the C-10 position, generating putative 17-nor-tricyclic ...
A natural brassinosteroid and a series of synthetic derivatives were found to be good inhibitors of herpes simplex virus type 1 (HSV-1) and arenavirus replication in cell culture. The synthetic compounds tested were analogues of the 24(S) ethylbrassinone. Compounds (22 R,23 R,24S)-2alpha, 3alpha,5alpha,22,23-pentahydroxy-stigmastan-6-one and (22R,23R,24S)-3beta-bromo-5alpha,22,23-trihydroxy sti...
The two isomeric 20(22)-olefins and the four isomeric 20,22-epoxides of cholesterol have been examined as possible intermediates in the conversion of cholesterol to pregnenolone both by crude extracts of acetone-dried bovine adrenal cortex mitochondria, and by a partially purified cytochrome P-450 specific for the side chain cleavage ( P 4 5 0 ~ ~ ~ ) . The quantities of pregnenolone (measured ...
Continuous chemical investigation of the gorgonian coral Pinnigorgia sp. resulted in the isolation of two new sterols, 5α,6α-epoxy-(22E,24R)-3β,11-dihydroxy-9,11-secoergosta-7-en-9-one (1) and (22R)-acetoxy-(24ξ)-ergosta-5-en-3β,25-diol (2). The structures of sterols 1 and 2 were elucidated using spectroscopic methods. Sterol 1 displayed inhibitory effects on the generation of superoxide anions...
Sexual morphogenesis in Achlya, a filamentous water mold, is initiated by two hormones. Hormone A, or antheridiol, is a C-29 steroid. Four stereoisomers of antheridiol have been synthesized. The natural one (antheridiol 22S 23R) and its 7-deoxy 7-dihydro form, when added to an aerated culture of hermaphroditic Achlya heterosexualis, stimulated this mold to secrete twice as much hormone B as the...
We consider the non-local energy-momentum tensor of quantum scalar and spinor fields in 2w-dimensional curved spaces. Working to lowest order in the curvature we show that, while the non-local terms proportional to 2R, 22R, . . . ,2w−2R are fully determined by the early-time behaviour of the heat kernel, the terms proportional to R depend on the asymptotic latetime behaviour. This fact explains...
BACKGROUND Certain phthalates can impair Leydig cell distribution and steroidogenesis in the fetal rat in utero, but it is unknown whether similar effects might occur in the human. OBJECTIVES Our aim in this study was to investigate the effects of di(n-butyl) phthalate (DBP), or its metabolite monobutyl phthalate (MBP), on testosterone production and Leydig cell aggregation (LCA) in fetal tes...
INTRODUCTION Interleukin-22 (IL-22) is a cytokine of IL-10 family with significant proliferative effect on different cell lines. Immunopathological role of IL-22 has been studied in rheumatoid arthritis (RA) and psoriasis. Here we are reporting the functional role of IL-22 in the inflammatory and proliferative cascades of psoriatic arthritis (PsA). METHOD From peripheral blood and synovial fl...
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