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1.
Andrea M. Powell W.Y. Chan Patrick Alvin Iris F. Litt 《Prostaglandins & other lipid mediators》1985,29(2):273-289
Although it has been demonstrated that primary dysmenorrhea is associated with elevated levels of PGF2α in the menstrual fluid, little is actually known of the menstrual-PG profiles of either dysmenorrheic or normal women. In this study, menstrual fluid from normal and dysmenorrheic women was collected from tampons and extracted for PG-like substances. The PGF2α, PGE2 and TXA2 content was analyzed by RIA.This study demonstrates that dysmenorrheics have significantly higher levels/concentrations of menstrual-PGF2α and PGe2 than do normal women, and that there is no difference in the menstrual-PGF2α: PGE2 ratio between the two groups. Also, there is no significant difference in the amount/concentration of menstrual-thromboxane between dysmenorrheic and normal women. Of the parameters considered, the levels/-concentrations of menstrual-PGF2α, PGE2 and TXA2, dysmenorrheic pain correlates best with the rate of menstrual-PGF2α release. 相似文献
2.
Abstract 2′-Azido-2′-deoxyuridine and 2′-azido-2′-deoxycytidine were evaluated for their inhibitory activity against ribonucleotide reductase and for subsequent cell growth inhibition. Their mono-and di-phosphates were synthesized and their inhibitory activities against the reductase were also determined in a permeabilized cell system, along with the two nucleosides. The results of the present study identify the first phosphorylation step involved in the conversion of the two azidonucleosides to the corresponding diphosphates to be rate-limiting in the overall activation. 相似文献
3.
2-acetamido-2-deoxy-4-O-β-D-galactopyranosyl-D-mannose (6) and -D-glucose (7) were prepared by addition of nitromethane to 3-O-β-D-galactopyranosyl-D-arabinose, followed by acetylation, ammonolysis, and application of the Nef reaction. Similarly, 2-acetamido-2-deoxy-4-O-β-D-mannopyranosyl-D-mannose (14) and -D-glucose (15) were prepared by the same scheme from 3-O-β-D-mannopyranosyl-D-arabinose. In the two series of experiments, 6 and 14 were the respective major products. Epimerization of the 2-acetamido-2-deoxy-D-mannose residue in 6 and 14 yielded 7 and 15, respectively. 相似文献
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Molecular beacons (MBs) have shown great potential for the imaging of RNAs within single living cells; however, the ability to perform accurate measurements of RNA expression can be hampered by false-positives resulting from nonspecific interactions and/or nuclease degradation. These false-positives could potentially be avoided by introducing chemically modified oligonucleotides into the MB design. In this study, fluorescence microscopy experiments were performed to elucidate the subcellular trafficking, false-positive signal generation, and functionality of 2′-O-methyl (2Me) and 2′-O-methyl-phosphorothioate (2MePS) MBs. The 2Me MBs exhibited rapid nuclear sequestration and a gradual increase in fluorescence over time, with nearly 50% of the MBs being opened nonspecifically within 24 h. In contrast, the 2MePS MBs elicited an instantaneous increase in false-positives, corresponding to ∼5–10% of the MBs being open, but little increase was observed over the next 24 h. Moreover, trafficking to the nucleus was slower. After 24 h, both MBs were localized in the nucleus and lysosomal compartments, but only the 2MePS MBs were still functional. When the MBs were retained in the cytoplasm, via conjugation to NeutrAvidin, a significant reduction in false-positives and improvement in functionality was observed. Overall, these results have significant implications for the design and applications of MBs for intracellular RNA measurement. 相似文献
6.
A new high-yield synthesis of 2-pyridylferrocene (1) without formation of the 1,1′-disubstituted product has been developed. Also the corresponding ruthenocene and cymantrene derivatives [C5H4(2-C5H4N)]MLn (MLn = Ru(C5H5) (2), Mn(CO)3 (3)) were prepared and fully characterized. Ortho-lithiation of 1 followed by electrophilic halogenation yielded [C5H3X(2-C5H4N)]Fe(C5H5) [X = F (4), Cl (5), Br (6), I (7)], with 4 only being the second reported and first fully characterized fluoroferrocene. The molecular structures of 1, 4 and 6 have been determined by X-ray crystallography. 相似文献
7.
Elevated CO2 (ambient + 35 Pa) increased shoot dry mass production in Avena fatua by 68% at maturity. This increase in shoot biomass was paralleled by an 81% increase in average net CO2 uptake (A) per unit of leaf area and a 65% increase in average A at the ecosystem level per unit of ground area. Elevated CO2 also increased ecosystem A per unit of biomass. However, the products of total leaf area and light-saturated leaf A divided by the ground surface area over time appeared to lie on a single response curve for both CO2 treatments. The approximate slope of the response suggests that the integrated light saturated capacity for leaf photosynthesis is 10-fold greater than the ecosystem rate. Ecosystem respiration (night) per unit of ground area, which includes soil and plant respiration, ranged from-20 (at day 19) to-18 (at day 40) mol m-2 s-1 for both elevated and ambient CO2
Avena. Ecosystem below-ground respiration at the time of seedling emergence was -10 mol m-2 s-1, while that occuring after shoot removal at the termination of the experiment ranged from -5 to-6 mol m-2 s-1. Hence, no significant differences between elevated and ambient CO2 treatments were found in any respiration measure on a ground area basis, though ecosystem respiration on a shoot biomass basis was clearly reduced by elevated CO2. Significant differences existed between leaf and ecosystem water flux. In general, leaf transpiration (E) decreased over the course of the experiment, possibly in response to leaf aging, while ecosystem rates of evapotranspiration (ET) remained constant, probably because falling leaf rates were offset by an increasing total leaf biomass. Transpiration was lower in plants grown at elevated CO2, though variation was high because of variability in leaf age and ambient light conditions and differences were not significant. In contrast, ecosystem evapotranspiration (ET) was significantly decreased by elevated CO2 on 5 out of 8 measurement dates. Photosynthetic water use efficiencies (A/E at the leaf level, A/ET at the ecosystem level) were increased by elevated CO2. Increases were due to both increased A at leaf and ecosystem level and decreased leaf E and ecosystem ET. 相似文献
8.
《Nucleosides, nucleotides & nucleic acids》2013,32(5-8):1251-1254
Abstract We present procedures for nucleoside and oligonucleotide synthesis, binding affinity (T m) and structural analysis (CD spectra) of 2′-deoxy-2′,2″-difluoro-α-D-ribofuranosyl and 2′-deoxy-2′,2″-difluoro-β-D-ribofuranosyl oligothymidylates. Possible reasons for the thermal instability of duplexes formed between these compounds and RNA or DNA targets are discussed. 相似文献
9.
Anilkumar R. Kore Bo Yang Balasubramanian Srinivasan Annamalai Senthilvelan 《Nucleosides, nucleotides & nucleic acids》2015,34(1):33-39
We describe concise and efficient synthesis of biologically very important 3′-O-tetraphosphates namely 2′-deoxyadenosine-3′-O-tetraphosphate (2′-d-3′-A4P) and 2′-deoxycytidine-3′-O-tetra-phosphate (2′-d-3′-C4P). N6-benzoyl-5′-O-levulinoyl-2′-deoxyadenosine was converted into N6-benzoyl-5′-O-levulinoyl-2′-deoxyadenosine-3′-O-tetraphosphate in 87% yield using a one-pot synthetic methodology. One-step concurrent deprotection of N6-benzoyl and 5′-O-levulinoyl groups using concentrated aqueous ammonia resulted 2′-d-3′-A4P in 74% yield. The same synthetic strategy was successfully employed to convert N4-benzoyl-5′-O-levulinoyl-2′-deoxycytidine into 2′-d-3′-C4P in 68% yield. 相似文献
10.
《Prostaglandins and medicine》1981,6(4):345-357
Regiospecific monomethyl prostaglandin F2α ethers (at 0–9, 0–11, and 0–15) have been prepared by total synthesis. The 9,15-bis-ether was also prepared. The 11- and 15-monoethers have been converted to the corresponding prostacyclins. Nuclear Magnetic Resonance (NMR) spectral comparisons indicate conformational changes associated with ether formation; nonetheless, the PGF2α monoethers all retain significant biological activity: 3–420% of natural PGF2α. The 9- and 15-methyl ethers show increased selectivity for luteolytic activity as measured in the hamster antifertility (HAF) assay. In contrast the prostacyclin ethers are essentially devoid of agonist activity on both the platelet and vasculature. Prostacyclin diastereomers [5a] also lack activity and it appears that any modification at or of the C-11 or C-15 functions reduces receptor binding by at least a factor of 100. 相似文献
11.
A. Halász A. Badaway J. Sawinsky E. Kozma-Kovács J. Beczner 《Folia microbiologica》1989,34(3):228-232
Fusarium graminearum andF. tricinctum were grown on moistened corn and rice. After inoculation the substrates were exposed to γ-irradiation and growth rate together
with mycotoxin production were measured. A delay in mycelium growth and an increase in F-2 and T-2 toxin production occurred
after irradiation with 1 and 3 kGy. The maximum F-2 production was 10.7 mg/kg on rice at 3 kGy, whereas T-2 was 735 μg/kg
on rice at 3 kGy. At 9 kGy neither growth nor toxin production could be detected in any inoculated corn and rice substrate. 相似文献
12.
Cyclooxygenase-2 (COX-2) activity has been implicated in the pathogenesis of cerebral ischemia. To determine whether COX-2
activity within the neuron itself exacerbates hypoxic neuronal injury, neuron-enriched cultures were subjected to anoxia.
Treatment with COX-2 selective antagonists decreased cell death. Neurons cultured from homozygous COX-2 gene disrupted mice
were resistant to hypoxia compared to those of heterozygotes. Infection of primary neurons with AAV expressing COX-2 exacerbated
cell death compared to neurons infected with enhanced green fluorescent protein (EGFP) control vector. Addition of PGE2, PGD2
or PGF2α to the medium exacerbated injury, suggesting that the deleterious effects of COX-2 overexpression in hypoxia could
be mediated by direct receptor mediated effects of prostaglandins. Overexpression of COX-2 did not increase expression of
cyclin D1 or phosphoretinoblastoma protein (pRb), or cleavage of caspase 3 suggesting that this cell cycle mechanism does
not mediate COX-2 toxicity in this model. 相似文献
13.
《Journal of Free Radicals in Biology & Medicine》1986,2(2):135-140
The intracellular steady-state concentrations of hydrogen peroxide or Superoxide anion were increased by inhibiting either catalase, glutathione peroxidase, or Superoxide dismutase activities. Catalase was inhibited with aminotriazole while glutathione peroxidase activity was blocked by eliminating reduced glutathione after addition of either iodoacetamide diethylmaleate or phorone. The concentration of aminotriazole that stimulated chemiluminescence in 50% (60 mM) was very similar to the Ki for catalase activity (70 mM). Cyanide, an inhibitor of both catalase and Superoxide dismutase, stimulated chemiluminescence in 50% at a concentration (0.15 mM) which is much closer from the Ki for Superoxide dismutase (0.25 mM) than from the Ki for catalase (15 μM). The Superoxide dismutase inhibitor diethyldithiocarbamate also increased chemiluminescence six- to ten-fold. Depletion of reduced glutathione stimulated spontaneous chemiluminescence when its concentration decreased below 4.5 μmol · g liver−1. The results shown herein suggest that the changes in the intracellular steady-state concentration occurring after inhibition of any antioxidant enzyme are responsible for the increased spontaneous chemilumi-nescence. Spontaneous chemiluminescence from intact cells may be used as a noninvasive method for monitoring intracellular free radical metabolism. 相似文献
14.
Maria D. Bratek-Wiewiórowska Maciej Wiewiórowski Magdalena Alejska Agnieszka Olszewska Krzysztof Woźniak 《Nucleosides, nucleotides & nucleic acids》2013,32(8):1825-1843
Abstract The crystal structures of cytidinium H-phosphonate monohydrate, bis 2′-deoxycytidinium H-phosphonate and 2′-deoxycytidinium H-phosphonate have been determined by single crystal X-ray diffraction and FTIR spectroscopy. The influence of protonation and hydrogen bond formation on geometry of the cytidine fragment has been studied. All three compounds have similar geometry and conformation but they form different H-bond networks. Contrary to the phosphates of cytidine and deoxycytidine, the phosphonates do not form direct base pairs but they strongly interacts with H3PO3 acid and/or its anions present in the crystal lattice. This seems to be more favourable than the base-base interactions. As a result a pleated sheets are formed consisting from alternating columns of the cations and anions. The sheets are joined by additional O-H… O=P bonds giving a 3D network. 相似文献
15.
Rising atmospheric carbon dioxide (CO2) has caused a suite of environmental issues, however, little is known about how the partial pressure of CO2 (pCO2) in freshwater will be affected by climate change. Freshwater pCO2 varies across systems and is controlled by a diverse array of factors, making it difficult to make predictions about future levels of pCO2. Recent evidence suggests that increasing levels of atmospheric CO2 may directly increase freshwater pCO2 levels in lakes, but rising atmospheric CO2 may also indirectly impact freshwater pCO2 levels in a variety of systems by affecting other contributing factors such as soil respiration, terrestrial productivity and climate regimes. Although future freshwater pCO2 levels remain uncertain, studies have considered the potential impacts of changes to pCO2 levels on freshwater biota. Studies to date have focused on impacts of elevated pCO2 on plankton and macrophytes, and have shown that phytoplankton nutritional quality is reduced, plankton community structure is altered, photosynthesis rates increase and macrophyte distribution shifts with increasing pCO2. However, a number of key knowledge gaps remain and gaining a better understanding of how freshwater pCO2 levels are regulated and how these levels may impact biota, will be important for predicting future responses to climate change. 相似文献
16.
《Inorganica chimica acta》1988,151(4):291-295
Complex formation between transition metal chlorides and the ligands 2-aminomethylpyridine (AMP) and 2-(2′-aminoethyl)pyridine (AEP) has been investigated. The complexes were characterized on the basis of elemental analysis, magnetic measurements and spectral studies. The cytotoxicity of the iron and copper complexes of AMP and AEP against Ehrlich ascites tumor cells has been measured. Brief incubation of cells and drugs was followed by implantation into the host mice; subsequent development of tumor cells was a measure of cytotoxicity. 相似文献
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Abstract 3-β-D-Ribofuranosylpyazolo[4,3-d]pyrimidines (formycins)1 modified in the heteroaromatic moiety are of biological interest as analogues of adenosine and guanosine, and have been the objects of intensive synthetic chemical effort by several groups.2-9 2′-Deoxynucleosides2c,2d,7b,13 and other analogties of the formycins modified in the sugar moiety10-12 are also of potential interest, but have been less extensively studied. Examples of the 2′-deoxyribonucleoside type known to date include the 2′-deoxy-6-thioguanosine analogue 1, the 2′-deoxyadenosine (dAdo) analogue 2 (2′-deoxyformycin A),10,13 and the 2-chloro-2′-deoxyadenosine analogue 3.7b Compound 2 was found to be 10-15 times more potent than 2′-deoxyadenosine as an inhibitor of the growth of S49 cells, a murine lymphoma line of T-cell origin.13 Activity depended on 5′- phosphorylation, since mutants lacking the enzymes adenosine kinase (AK) and deoxycytidine kinase (dCK) were insensitive to the drug. Furthermore, activity was comparable in the presence and absence of an AK inhibitor, suggesting that 2, unlike dAdo, may be a poor substrate for adenosine deaminase. That 5′-phosphorylation of 2 was mediated by AK rather than dCK was indicated by the fact that miitants lacking only dCK retained sensitivity. This contrasted with the behavior of dAdo, which is known to be n substrate for both AK and dCK.14 相似文献
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The proposed valence force field allows us to reproduce the vibration modes of 2-deoxythymidine and 2-deoxyadenosine. The present calculations are based on the Wilson GF-method and a non-redundant set of symmetrical coordinates. The calculated wavenumbers have been compared to the available Raman and infrared peak positions observed in solid, amorphous or aqueous samples. Moreover, the results obtained with the present force field allow us to assign some of the characteristic vibration modes for the thymidine and adenosine residues involved in DNA double-helical chains. 相似文献