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41.
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The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs. 相似文献
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The structural features of calcium guanosine-3′,5′-cytidine monophosphate (GpC) have been elucidated by X-ray diffraction analysis. The molecule was crystallized in space group P21 with cell constants of a = 21.224 Å, b = 34.207 Å, c = 9.327 Å, and β = 90.527°, Z = 8. The hydration of the crystal is 21% by weight with 72 water molecules in the unit cell. The four GpC molecules in the asymmetric unit occur as two Watson-Crick hydrogen-bonded dimers related by a pseudo-C face centering. Each dimer consists of two independent GpC molecules whose bases are hydrogen bonded to each other in the traditional Watson-Crick fashion. Each dimer possesses a pseudo twofold axis broken by a calcium ion and associated solvent. The four molecules are conformationally similar to helical RNA, but are not identical to it or to each other. Instead, values of conformational angles reflect the intrinsic flexibility of the molecule within the range of basic helical conformations. All eight bases are anti, sugars are all C3′-endo, and the C4′-C5′ bond rotations are gauche-gauche. The R factor is 12.6% for 2918 observed reflections at 1.2-Å resolution. 相似文献
45.
Ryan M. Summers Jennifer L. Seffernick Erik M. Quandt Chi Li Yu Jeffrey E. Barrick Mani V. Subramanian 《Journal of bacteriology》2013,195(17):3933-3939
Caffeine and other N-methylated xanthines are natural products found in many foods, beverages, and pharmaceuticals. Therefore, it is not surprising that bacteria have evolved to live on caffeine as a sole carbon and nitrogen source. The caffeine degradation pathway of Pseudomonas putida CBB5 utilizes an unprecedented glutathione-S-transferase-dependent Rieske oxygenase for demethylation of 7-methylxanthine to xanthine, the final step in caffeine N-demethylation. The gene coding this function is unusual, in that the iron-sulfur and non-heme iron domains that compose the normally functional Rieske oxygenase (RO) are encoded by separate proteins. The non-heme iron domain is located in the monooxygenase, ndmC, while the Rieske [2Fe-2S] domain is fused to the RO reductase gene, ndmD. This fusion, however, does not interfere with the interaction of the reductase with N1- and N3-demethylase RO oxygenases, which are involved in the initial reactions of caffeine degradation. We demonstrate that the N7-demethylation reaction absolutely requires a unique, tightly bound protein complex composed of NdmC, NdmD, and NdmE, a novel glutathione-S-transferase (GST). NdmE is proposed to function as a noncatalytic subunit that serves a structural role in the complexation of the oxygenase (NdmC) and Rieske domains (NdmD). Genome analyses found this gene organization of a split RO and GST gene cluster to occur more broadly, implying a larger function for RO-GST protein partners. 相似文献
46.
Muthu Vengaian Karmegam Sekar Karuppannan Denzil Britto Christopher Leslee Singaravadivel Subramanian Sivaraman Gandhi 《Luminescence》2020,35(1):90-97
A phenothiazine–rhodamine (PTRH) fluorescent dyad was synthesized and its ability to selectively sense Zn2+ ions in solution and in in vitro cell lines was tested using various techniques. When compared with other competing metal ions, the PTRH probe showed the high selectivity for Zn2+ ions that was supported by electronic and emission spectral analyses. The emission band at 528 nm for the PTRH probe indicated the ring closed form of PTRH, as for Zn2+ ion binding to PTRH, the λem get shift to 608 nm was accompanied by a pale yellow to pink colour (under visible light) and green to pinkish red fluorescence emission (under UV light) due to ring opening of the spirolactam moiety in the PTRH ligand. Spectral overlap of the donor emission band and the absorption band of the ring opened form of the acceptor moiety contributed towards the fluorescence resonance energy transfer ON mechanism for Zn2+ ion detection. The PTRH sensor had the lowest detection limit for Zn2+, found to be 2.89 × 10?8 M. The sensor also demonstrated good sensing application with minimum toxicity for in vitro analyses using HeLa cells. 相似文献
47.
Gobinath M. Subramanian N. Alagarsamy V. Nivedhitha S. Solomon Viswas Raja 《Russian Journal of Bioorganic Chemistry》2020,46(3):403-408
Russian Journal of Bioorganic Chemistry - Some new 1-substituted-4-(4-nitrophenyl)-[1,2,4]triazolo[4,3-a]quinazolin-5(4H)-ones were synthesized and screened for their H1-antihistaminic activity.... 相似文献
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Isabel A. Cáceres Mariana Arcaya Eugene Declercq Candice M. Belanoff Vanitha Janakiraman Bruce Cohen Jeffrey Ecker Lauren A. Smith S. V. Subramanian 《PloS one》2013,8(3)
Objective
We examined the extent to which differences in hospital-level cesarean delivery rates in Massachusetts were attributable to hospital-level, rather than maternal, characteristics.Methods
Birth certificate and maternal in-patient hospital discharge records for 2004–06 in Massachusetts were linked. The study population was nulliparous, term, singleton, and vertex births (NTSV) (n = 80,371) in 49 hospitals. Covariates included mother''s age, race/ethnicity, education, infant birth weight, gestational age, labor induction (yes/no), hospital shift at time of birth, and preexisting health conditions. We estimated multilevel logistic regression models to assess the likelihood of a cesarean deliveryResults
Overall, among women with NTSV births, 26.5% births were cesarean, with a range of 14% to 38.3% across hospitals. In unadjusted models, the between-hospital variance was 0.103 (SE 0.022); adjusting for demographic, socioeconomic and preexisting medical conditions did not reduce any hospital-level variation 0.108 (SE 0.023).Conclusion
Even after adjusting for both socio-demographic and clinical factors, the chance of a cesarean delivery for NTSV pregnancies varied according to hospital, suggesting the importance of hospital practices and culture in determining a hospital''s cesarean rate. 相似文献50.
Efthalia K. Chatziefstratiou Gil Bohrer Anthony S. Bova Ravishankar Subramanian Renato P. M. Frasson Amy Scherzer Bret W. Butler Matthew B. Dickinson 《PloS one》2013,8(7)
FireStem2D, a software tool for predicting tree stem heating and injury in forest fires, is a physically-based, two-dimensional model of stem thermodynamics that results from heating at the bark surface. It builds on an earlier one-dimensional model (FireStem) and provides improved capabilities for predicting fire-induced mortality and injury before a fire occurs by resolving stem moisture loss, temperatures through the stem, degree of bark charring, and necrotic depth around the stem. We present the results of numerical parameterization and model evaluation experiments for FireStem2D that simulate laboratory stem-heating experiments of 52 tree sections from 25 trees. We also conducted a set of virtual sensitivity analysis experiments to test the effects of unevenness of heating around the stem and with aboveground height using data from two studies: a low-intensity surface fire and a more intense crown fire. The model allows for improved understanding and prediction of the effects of wildland fire on injury and mortality of trees of different species and sizes. 相似文献