Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
The aim of the article is to determine whether corneal endothelial cell density and other characteristics, such as cell area, pleomorphism and polymegathism, are affected by diabetes.Corneal endothelial cell density and other characteristics of donor eyes collected during 2007 and 2008 in a local Eye Bank were measured by the HAI Eyebank Specular Microscope System.Adult donors aged 21 or older who consented to research were divided into healthy versus compromised eye-status groups based on eye disease or past eye surgeries.Differences in corneal measures between diabetic and non-diabetic subjects were analyzed separately in each group via Mixed Models ANCOVA, with Diabetes as the fixed effect, Donor as the random effect, and Age as the continuous covariate.A total of 253 subjects met study criteria, of which 81 (32%) had diabetes.In the 180 subjects with healthy eye status, the medians (ranges) of age were 62 (29-78) years among 52 diabetics (29%), versus 57 (21-79) years among non-diabetics (P=0.013).In the 73 subjects with compromised eye status, the medians (ranges) of age were 70 (32-78) years among 29 diabetics (40%), versus 70 (29-79) years among nondiabetics (P=0.77).Between diabetics and non-diabetics, eye disease and past eye surgeries were well-balanced in the compromised eye-status group, while race and sex were wellbalanced in both eye-status groups.Results from separate analyses on the two groups indicated that diabetes did not affect corneal cell density or other corneal-cell characteristics analyzed.Even though diabetics constituted a large percentage of the Eye Bank donor population, this disease did not have a statistically significant impact on corneal endothelial cell density, cell area, pleomorphism or polymegathism.
A novel approach to the synthesis of C-ring substituted xanthones utilising the [4 + 2] cycloaddition reactions of enamines with aromatically substituted vinylchromones has been developed. 1-Methyl-, 1-ethyl-, 2-methyl- and 2-ethyl-substituted xanthones are obtained in a one-pot synthesis from the reaction of pyrrolidine enamines derived from acetone, butan-2-one, propanal and butanal respectively, when taken as solvent incorporating a catalytic amount of pyrrolidine. Some 1-methylidene- and 1-methylidene-2-methyl-substituted tetrahydroxanthones were also obtained and these compounds are proposed to be intermediates in the reaction, since they undergo facile conversion to 1-methyl- and 1,2-dimethyl-xanthones. Further evidence for the proposed reaction pathway was obtained from the isolation of a 1-pyrrolidino-2,2-dimethyl substituted tetrahydroxanthone from the reaction between a vinylchromone and the pyrrolidine enamine of 2-methylpropanal.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Abstract The novel potential antitumour agent 5‐fluoro‐2‐(4‐amino‐3‐methylphenyl)benzothiazole (5F203) has been radiolabelled with fluorine‐18 by reaction of an amino protected trimethyltin precursor with molecular fluorine ( 18 F‐F) followed by alkaline deprotection of the amino group. [ 18 F]5F203 was obtained in ca 10% radiochemical yield in ca. 60 mins from end of bombardment.
The self-assembly of a peptide based on a sequence from the amyloid β peptide but incorporating the non-natural amino acid β-2-thienylalanine (2-Thi) has been investigated in aqueous and methanol solutions. The peptide AAKLVFF was used as a design motif, replacing the phenylalanine residues (F) with 2-Thi units to yield (2-Thi)(2-Thi)VLKAA. The 2-Thi residues are expected to confer interesting electronic properties due to charge delocalization and π-stacking. The peptide is shown to form β-sheet-rich amyloid fibrils with a twisted morphology, in both water and methanol solutions at sufficiently high concentration. The formation of a self-assembling hydrogel is observed at high concentration. Detailed molecular modeling using molecular dynamics methods was performed using NOE constraints provided by 2D-NMR experiments. The conformational and charge properties of 2-Thi were modeled using quantum mechanical methods, and found to be similar to those previously reported for the β-3-thienylalanine analogue. The molecular dynamics simulations reveal well-defined folded structures (turn-like) in dilute aqueous solution, driven by self-assembly of the hydrophobic aromatic units, with charged lysine groups exposed to water.
I-motif formation has been confirmed in a number of gene promoter sequences known to form G-quadruplex structures. I-motif formation can occur close to physiological temperature and pH for h-tert and PDGF-A. The i-motif structure formed by a HIF-1α promoter sequence shows unexpected stability near neutral pH.
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