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R Groups (r + groups)
Selected AbstractsEffects of L-arginine and L-carnitine in hypoxia/reoxygenation-induced intestinal injuryPEDIATRICS INTERNATIONAL, Issue 1 2005Ceyda Kabaroglu Abstract,Background:,This study was designed to show the role of oxidative stress, nitric oxide and glutathione-related antioxidant enzymes in hypoxia/reoxygenation (H/R)-induced intestinal injury model in mice and to evaluate the potential benefits of arginine and carnitine supplementation. Methods:,A total of 28 young Balb/c mice were divided into four groups: Group 1 (untreated) was given physiological saline before the experiment; group 2 H/R mice were supplemented with L-arginine; group 3 H/R mice were given L-carnitine for 7 days; and group 4 mice served as controls. At the end of day 7, H/R injury was induced and intestinal tissue malondialdehyde (MDA), nitrate levels and glutathione peroxidase (GSH-Px), glutathione reductase (GR) and glutathione-S-transferase (GST) activities were measured. Results:,MDA levels were higher in the untreated animals than in the other three groups. MDA levels were higher in the L-arginine-treated animals than in the L-carnitine-treated animals. Nitrate levels were found to be increased in the L-arginine-treated group when compared to the controls. GSH-Px and GR activities were increased in the untreated, the L-arginine and the L-carnitine-treated H/R groups when compared to the control group. GST activities were indifferent between the groups. Conclusions:,Oxidative stress contributes to the pathogenesis of H/R-induced intestinal injury. The glutathione redox cycle may have a crucial role in the H/R-induced intestinal injury. L-arginine and L-carnitine supplementations ameliorate the histological evidence of H/R-induced intestinal injury and decrease lipid peroxidation but do not alter the glutathione-related antioxidant enzyme activities. [source] Role of interleukin-18 in the development of acute pulmonary injury induced by intestinal ischemia/reperfusion and its possible mechanismJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 2 2007Yong-jie Yang Abstract Background and Aims:, Lung injury is an important target for the systemic inflammatory response associated with intestinal ischemia/reperfusion (I/R). In the present study, the role of interleukin (IL)-18 in the development of acute pulmonary injury induced by intestinal I/R and its possible mechanism in relation to the increased activity of inducible nitric oxide synthase and tumor necrosis factor (TNF)-, were investigated. Methods:, Mice were randomly divided into three groups: normal control group without operation; sham group with sham operation; and I/R group in which mice underwent superior mesenteric artery occlusion for 30 min followed by reperfusion for 3 h. Each group received pretreatment with exogenous IL-18, anti-IL-18 neutralizing antibody or L-NIL, the selective inhibitor of inducible nitric oxide synthase, 30 min before ischemia. The expression of TNF-, was detected by reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Lung injury was evaluated by means of Evans blue dye (EBD) concentration, myeloperoxidase (MPO) activity and morphological analysis. Results:, The experimental results showed that both in the sham-operated and I/R groups of animals, pretreatment with exogenous IL-18 clearly enhanced pulmonary MPO activity, microvascular leakage and the expression of TNF-, mRNA and protein. In contrast, IL-18 did not increase the TNF-, level and degree of lung injury, although it clearly enhanced the pulmonary MPO activity in normal animals. Meanwhile, IL-18 antibody given prior to ischemia led to a reduction in the sequestration of neutrophils, extravasation of EBD and downregulation of the serum level of TNF-, in the I/R group of animals. In addition, selective inhibition of inducible nitric oxide synthase (iNOS) that inhibited plasma extravasation and pulmonary injury without affecting the MPO activity could be demonstrated in all treated animals. Conclusions:, These data suggested a role of IL-18 in the activation and sequestration of neutrophils in lungs. Our results were consistent with the hypothesis that increased sequestration of neutrophils and microvascular leakage might, respectively, relate to the increased IL-18 level and the elevation of TNF-,/iNOS activity, and these two aspects might synergically contribute to intestinal I/R-induced pulmonary dysfunction. [source] Regioselective Synthesis of [60]Fullerene ,5 -Indenide R3C60 - and ,5 -Cyclopentadienide R5C60 - Bearing Different R Groups.CHEMINFORM, Issue 42 2003Motoki Toganoh No abstract is available for this article. [source] Synthesis and Conformation Analysis of New Perphosphorylated Calix[4]resorcinarenesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 23 2004Vera I. Maslennikova Abstract The octaphosphorylation of calix[4]resorcinarenes 1 by 2-dialkylamino-1,3,2-diheterophosphorinanes 2 is described, and the effect of different factors on the structures of the resulting perphosphorylated products 3,5 was studied. Conformation analysis of these compounds by correlated 2D NMR spectroscopy and X-ray diffraction analysis was performed, and it was found that compounds 3,5, like the initial resorcinarenes 1, each have the all - cis configuration of the R groups in the methylidene bridges of the calixarene system, but different orientations of benzene rings and phosphorinane fragments with respect to one another and to the macrocycle plane. Perphosphorylated resorcinarenes 3a,c, 4a and 5a with R = alkyl exist in flattened cone conformations with the phosphorinane fragments on the same side of the macrocycle plane. The conformations of the perphosphorylated resorcinarenes 3d, 4b and 5b with R = Ph change to forms intermediate between flattened cone and 1,3 - alternate. The phosphorus fragments in these compounds are located on opposite sides of the macrocycle plane. It was shown that the oxidation and sulfurisation of phosphocalixarenes 3 proceed without any change in the spatial organisation of the macrocyclic system. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] The Conformation of Alkyl Benzyl Alcohols Studied by ab initio MO Calculations , A Comparison with IR and NMR Spectroscopic DataEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 11 2004Osamu Takahashi Abstract Ab initio MO calculations were carried out for the conformations of a series of alkyl-substituted benzyl alcohols C6H5CH2CHOH,R (R = CH3, C2H5, iPr, tBu) at the MP2/6-311G(d,p)//MP2/6-31G(d) level. It was found that the conformation where the OH group is gauche to the phenyl group is the most stable. The geometry where both the OH and R groups are close to phenyl is the second most stable. This finding has been interpreted on the grounds of the attractive OH/, and CH/, hydrogen bonds and a repulsive van der Waals interaction between vicinal CH groups. NMR nuclear Overhauser effects, spin-coupling data, and IR spectroscopic data are consistent with the conclusion given by the MO calculations. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Effect of the side chain size of 1-alkyl-pyrroles on antioxidant activity and ,Laba' garlic greeningINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 10 2008Dan Wang Summary Previous studies showed that 1-alkyl-pyrroles not only occur in fresh food products postulated as a natural antioxidant but also might be involved in garlic greening. In the present study, a series of 1-alkyl-pyrroles with different side chain size were synthesised to study the relationship of structure and antioxidative activity and their effects on ,Laba' garlic greening. The antioxidative activity of these compounds was evaluated by the method of scavenging ABTS, and DPPH,. Results showed that increasing the size of R groups on the side chain, the antioxidative activity decreased gradually against the two radicals. The 1-alkyl-pyrroles generally exhibited stronger scavenging activities against ABTS, than DPPH,. In contrast, their corresponding amino acids except for tyrosine showed almost no antioxidative activities while pyrrole exhibited much weaker activity as compared with the 1-alkyl-pyrroles, suggesting that the 1-alkyl-pyrroles donate H-atom from pyrrole moiety rather than side chain to quench the two radicals. On the other hand, all 1-alkyl-pyrroles can turn newly harvested garlic green but to a different extent. All these results suggested that these pyrrole derivatives occurring in foodstuff played an important role in either protecting foodstuff from oxidation or acting on pigment precursors during ,Laba' garlic greening. [source] New , -Conjugated Polymers Containing 1,3,5-Triazine Units in the Main Chain: Synthesis and Optical and Electrochemical Properties of the Polymers,MACROMOLECULAR RAPID COMMUNICATIONS, Issue 12 2005Shijie Ren Abstract Summary: Three new soluble , -conjugated polymers containing 1,3,5-triazine units in the main chain, Pa,Pc, were synthesized. The polymers showed optical properties in solution that were mainly dependant on the properties of the substituting R groups, on the triazine ring. Hence, Pa and Pb (R,=,H and OCH3, respectively) showed blue photoluminescent (PL) emission with high quantum yields (QY) even in polar solvents, whereas Pc (R,=,N,N -dimethylamino) gave green-blue PL emission with very low QY. The PL spectra of the polymers in solution were concentration and polarity dependent, which suggested the formation of an exciplex. The three new soluble , -conjugated polymers containing 1,3,5-triazine units in the main chain synthesized here. [source] Syntheses and Crystal Structure of Six-coordinated Diorgnotin Complexes with 2, 5-Dimercapto-4-phenyl-1, 3,4-thiodiazoIe,CHINESE JOURNAL OF CHEMISTRY, Issue 7 2003Chun-Lin Ma Abstract The reactions of diorganotin dichloride [Ph2SnCl2, (PhCH2)2 -SnCl2 or (n -Bu)2SnCl2] with potassium salt of 2, 5-dimercapto-4-phenyl-1, 3, 4-thiodiazole gave complexes R2Sn (S3N2C8H5)2 (4: R = Ph; 5: R = PhCH2 and 6: R = n -Bu), respectively. Characterizations were carried out for all complexes by IR, 1H NMR spectra and X-ray crystallography analysis. Including the Sn,N interaction, the three complexes all have six-coordinated distorted octahedral geometry. Based on the requence of stereochemical constraint sequence, phenyl,benzyl > n -butyl, the less the effect of the stereochemical constraint of R groups, the shorter the Sn,N length. In complexes 5 and 6, there exist S,S weak intra-molecular interactions, through which the complexes are dissociated into loose 2D polymers. All three complexes show antitumour activity in bioactivity measurements. [source] | |||||||||||||