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991.
Summary. In this paper, the analog of arginine residues in peptides was synthesized and characterized by ESI-MS/MS (electrospray ionization
with tandem mass spectrometry), 31P NMR, 1H NMR, IR and high-resolution mass spectrometry. When the Todd reaction activity of the guanidino group in free arginine and
the arginine peptide analog were compared, it was found that the proton affinity of the guanidino group was decreased when
both the N- and the C-terminal were blocked. As a result, the guanidino group of arginine residues in peptides could be phosphorylated
under the Todd reaction condition, but not the free arginine. This result was further proved by the theoretical calculation
of their proton affinity. 相似文献
992.
Summary. Two synthetic routes to bis-armed-α-amino acid derivatives are described. The first route involves alkylation of dibromo derivatives
with ethyl isocyanoacetate under phase-transfer catalysis (PTC) conditions. The second route uses a palladium-mediated Suzuki–Miyaura
cross-coupling reaction between a DL-4-boronophenylalanine derivative and aromatic diiodo (or dibromo) compounds. 相似文献
993.
Summary. Two Lys–Lys crosslinks, 1,3-bis-(5-amino-5-carboxypentyl)-1H-imidazolium (GOLD) and 1,3-bis(5-amino-5-carboxypentyl)-4-methyl-1H-imidazolium
(MOLD) salts, have been synthesized by the reaction of imidazole or 4(5)-methyl imidazole with 5-(4-bromobutyl)-hydantoin
followed by the hydrolysis of 1,3-substituted imidazolium derivatives by 6.0 N HCL at 110 °C. Treatment of GOLD and MOLD with
hydrogen peroxide in acetic acid leads to MOLD oxidation only. The oxidation product of MOLD was detected in cataractous lens
proteins. 相似文献
994.
Protective roles of puerarin and Danshensu on acute ischemic myocardial injury in rats 总被引:8,自引:0,他引:8
Ischemic heart diseases have been the leading cause of death in both developed and developing countries over the past decades. The aim of this study was to investigate the cardioprotective effects of the complex preparation (called Shenge), made of puerarin (isolated from Pueraria lobata Ohwi., also called Kudzu) and Danshensu (isolated from the Chinese herb, Salvia miltiorrhiza), on acute ischemic myocardial injury in rats and its underlying mechanisms. The left anterior descending (LAD) coronary artery was occluded to induce myocardial ischemia in the hearts of SD rats. Shenge was injected into the tail vein 15 min after occlusion at doses of 0, 30, 60, or 120 mg/kg body wt. ST elevation was then measured at 60, 120, and 240 min after Shenge administration. The ischemic size, serum levels of creatine kinase isoenzyme-MB (CK-MB), lactate dehydrogenase (LDH), superoxide dismutase (SOD) and malondialdehyde (MDA), and ST elevation were measured after the rats were sacrificed. Shenge decreased ST elevation induced by acute myocardial ischemia, reduced ischemic size, serum levels of CK-MB, LDH and MDA, and increased serum activity of SOD in a dose-dependent manner. The combined use of puerarin and Danshensu at a ratio of 1:1 showed the most effective activity. In conclusion, Shenge exerts significant cardioprotective effects against acute ischemic myocardial injury in rats, likely through its antioxidant and anti-lipid peroxidation properties, and thus may be an effective and promising medicine for both prophylaxis and treatment of ischemic heart disease. 相似文献
995.
The actute phase reaction mediated by the proinflammatory cytokine IL6 initiates a number of metabolic changes in the liver,
which may contribute to the pathogenesis of the septic shock during prolonged exposition. Here, the impact of IL6 on the hepatic
glucose providing capacity was studied by monitoring glycogen degradation and the expression of the gluconeogenic phosphoenolpyruvate
carboxykinase (PCK1) in rat livers during the daily feeding rhythm. Eight hours after i.p. injection of IL6, mRNA levels of
α2-macroglobulin, a prominent acute phase reactant in rat liver, were elevated as shown by Northern blot analysis and in situ
hybridization (ISH). PCK1 mRNA levels were decreased by IL6 to 50% of levels in untreated animals due to the reduction of
PCK1 mRNA in the periportal zone of the liver as shown by ISH. PCK1 enzyme activity was not affected by IL6. Glycogen degradation
was accelerated by IL6, which led to nearly complete depletion of glycogen pools in periportal areas 8 h after IL6 injection.
This was very likely due to inhibition of glycogen pool replenishment. Thus, the depletion of glycogen stores in the liver
might contribute to the impairment of hepatic glucose production during prolonged acute phase challenge. 相似文献
996.
Bengt Steen 《The International Journal of Life Cycle Assessment》2007,12(2):103-108
Goal, Scope and Background The life cycles of many products including textiles contain chemicals for which process flow data are not known or are too
time consuming to collect. Although each chemical may not contribute significantly to the LCA results of the product, which
might justify excluding them, but together their contribution could be significant. Similarly, rough estimates of the process
flows for the production of a single chemical may be very uncertain and considered meaningless, while the estimates of the
cumulative data of process flows for several chemicals may be less uncertain and be a meaningful contribution to the quality
of the LCA results. There are methods for estimation of process flows for different types of products, with varying demands
regarding input data and time and with varying accuracy of the results. This work contributes to the available methods, focusing
on simple estimations for production of chemical substances. The goal was to create a fast method for estimation of emissions,
resource and energy flows (process flows) for the production of chemicals, based on easily available data on the properties
of the chemicals. The process flows investigated were limited to those normally associated with process industries and contributing
most to depletion of resources, to global warming, acidification, eutrophication and photochemical ozone production, i.e.
use of energy, crude oil, coal, natural gas, uranium in ore and emissions of CO2, SOx, NOx, NMVOC, methane, BOD, COD and total
N. Toxic substances were excluded, since toxic emissions are substance specific and cannot be included in a generalization.
Method Available data for the process flows for the production of chemicals of mainly fossil origin were correlated to properties
of chemicals such as amount of carbon in the molecule, heat of formation and average number of chemical reaction steps in
the production. The production procedures were found in readily available literature. Up to about six reaction steps were
evaluated in the correlation study. The variations in the process flows among the chemicals studied were calculated.
Results and Discussion There were weak correlations between average number of chemical reaction steps in the production and energy use, COD measured
in water emissions, and SOx and NOx emissions to air. For the remaining properties of chemicals and process flows, there were
only weak correlations for share of double bonding in the molecule if only molecules containing double bondings were included.
Conclusions The precision in estimation of the process flows increases non-significantly when adding information on the number of reaction
steps or share of double bonding for chemicals containing double bonding is added.
Recommendations and Outlook It seems reasonable to start with a simple grouping method to estimate the process flows for the production of a chemical
of fossil origin. Further investigations might investigate whether there is a correlation between process flows and the costs
of chemicals, and further study the correlations between process flows and share of double bonding for chemicals containing
double bondings. 相似文献
997.
Rmy Fortrie David Gatineau Damien Hrault Aurlie Bal Jean-Valre Naubron Laurent Giordano Grard Buono 《Chirality》2022,34(1):27-33
The racemization mechanism of tert-butylphenylphosphido-borane is investigated experimentally and theoretically. Based on this converging approach, it is shown, first, that several phosphido-borane molecular species coexist at the time of the reaction and, second, that one particular of both initially assumed reactive routes most significantly contribute to the overall racemization process. From our converging modeling and experimental measurement, it comes out that the most probable species to be here encountered is a phosphido-borane-Li (THF)2 neutral solvate, whose P-stereogenic center monomolecular inversion through a Y-shaped transition structure (ΔrG°≠: 81 kJ mol?1) brings the largest contribution to the racemization process. 相似文献
998.
《Indian pacing and electrophysiology journal》2022,22(6):291-294
Brugada phenocopies (BrP) include several conditions with a common electrocardiographic (ECG) pattern that are indistinguishable from classical Brugada syndrome (BrS). In this report, we describe two cases of acute myocardial infarction (AMI) presenting as BrP. The majority of cases of BrP in AMI have been reported due to right coronary artery (RCA) occlusion. Rarely, the left anterior descending artery (LAD) is incriminated as the cause. In both our cases of BrP, LAD was the culprit vessel. 相似文献
999.
1000.
《Theriogenology》2015,84(9):1477-1483.e1
Single-nucleotide polymorphisms (SNPs) located at microRNA-binding sites (miR-SNPs) can affect the expression of genes. This study aimed to identify the miR-SNPs associated with litter size. Guanzhong (n = 321) and Boer (n = 191) goat breeds were used to detect SNPs in the caprine prolactin receptor (PRLR) gene by DNA sequencing, primer-introduced restriction analysis-polymerase chain reaction, and polymerase chain reaction-restriction fragment length polymorphism. Three novel SNPs (g.151435C>T, g.151454A>G, and g.173057T>C) were identified in the caprine PRLR gene. Statistical results indicated that the g.151435C>T and g.173057T>C SNPs were significantly associated with litter size in Guanzhong and Boer goat breeds. Further analysis revealed that combinative genotype C6 (TTAACC) was better than the others for litter size in both goat breeds. Furthermore, the PRLR g.173057T>C polymorphism was predicted to regulate the binding activity of bta-miR-302a. Luciferase reporter gene assay confirmed that 173057C to T substitution disrupted the binding site for bta-miR-302a, resulting in the reduced levels of luciferase. Taken together, these findings suggested that bta-miR-302a can influence the expression of PRLR protein by binding with 3′untranslated region, resulting in that the g.173057T>C SNP had significant effects on litter size. 相似文献