Modified 26 and 28 pi hexaphyrins with five meso-links: optical, redox, and structural properties.

The syntheses of new aromatic 26pi and non-aromatic 28pi hexaphyrins through a [4+2] acid catalyzed condensation of easily available and air-stable precursors are reported. Both 26pi and 28pi hexaphyrins are reversibly transformed into one another by two-electron reduction with NaBH(4) or two-electron oxidation with dichlorodicyanobenzoquinone (DDQ) respectively. Detailed optical and NMR spectral studies suggests that the [26]hexaphyrin is aromatic and possesses a diatropic ring current, while [28]hexaphyrin exhibits non-aromatic characteristics.

Association of low heart rate variability with atherosclerotic cardiovascular disease in hemodialysis patients.

Objective: The aim of this study was to investigate the left-ventricular (LV) mass-adjusted association between low heart rate variability (HRV) and atherosclerotic cardiovascular disease (ASCVD) among hemodialysis patients in Kuwait.

Subjects And Methods: One hundred and eight patients were enrolled in the study. HRV time domain measures were obtained by 48-hour Holter monitoring, including the standard deviation of all R-wave-to-R-wave (RR) intervals (SDNN), standard deviation of all 5-min averaged intervals (SDANN), HRV triangular index (HRV-TI), percent of adjacent RR intervals differing by >50 ms (pNN50), and root mean square of sums of squares of all differences (rMSSD).

Features of homotetrameric molecular association in protein crystals.

The crystal structures of proteins showing homotetrameric association, a common feature observed in many lectins, have been analyzed in order to understand the characteristics of tetrameric association in terms of the arrangement of subunits and their biological significance. The analysis could group the tetramer units into the following four categories. (i) Tetrahedral molecules, in which the four monomers form a nearly perfect tetrahedral arrangement.

Bleeding duodenal lipoma treated with endoscopic polypectomy.

Duodenal lipomas are relatively uncommon and are rarely a source of severe upper gastrointestinal haemorrhage. We report the case of a 70-year-old woman who presented with significant upper GI bleed due to a large bleeding duodenal lipoma that was successfully treated by endoscopic polypectomy.

Desmoid tumor of the tongue.

Desmoid tumors are rare neoplasms accounting for 0.03% of all neoplasms and have an estimated incidence of 2 to 4 per million per year. World Health Organization currently refers to all of the deep types of fibromatosis as desmoid-type of fibromatoses.

Typical aromatic noncovalent interactions in proteins: A theoretical study using phenylalanine.

A systematic study of CH...

Theoretical studies on the carcinogenic activity of diol epoxide derivatives of PAH: proton affinity and aromaticity as decisive descriptors.

A comparative study between bay-region and nonbay-region diol epoxide (DE) derivatives of seventeen carcinogenic polycyclic aromatic hydrocarbons (PAHs) was carried out using the B3LYP/6-31G(d,p) level of density functional theory to understand the factors responsible for the increased carcinogenic activity of bay-region derivatives. Molecular electrostatic potential analysis as well as proton affinity calculations showed that the epoxide sites of bay-region derivatives are much more reactive than the corresponding nonbay-region analogs. The charge delocalization mode in the carbocation intermediates resulting from the protonation reactions was followed through LUMO analysis.

Use of molecular electrostatic potential for quantitative assessment of inductive effect.

Density functional theory computations at the B3LYP/6-31G(d,p) level have been carried out for three types of model compounds, viz. (i) 4-substituted bicyclo[2.2.

Comparative studies of two araceous lectins by steady state and time-resolved fluorescence and CD spectroscopy.

Transitions in the tryptophan microenvironment and secondary structure of two monocot lectins from Sauromatum guttatum and Arisaema tortuosum under different denaturing conditions were studied by steady state and time resolved fluorescence and CD spectroscopy. The lectins exist as tetramers with a single tryptophan residue estimated per monomer, present in a polar environment. Quenching with ionic quenchers showed predominantly electropositive environment for tryptophan residues.

Analysis of reactive oxygen species and antioxidant defenses in complex I deficient patients revealed a specific increase in superoxide dismutase activity.

The mechanism of free radical production by complex I deficiency is ill-defined, although it is of significant contemporary interest. This study studied the ROS production and antioxidant defenses in children with mitochondrial NADH dehydrogenase deficiency. ROS production has remained significantly elevated in patients compared to controls.

Liquid crystalline phase behavior of high molecular weight DNA: a comparative study of the influence of metal ions of different size, charge and binding mode.

The ability of Li(+), Na(+), K(+), Rb(+), Cs(+), Mg(2+), Ca(2+), Sr(2+), Ba(2+), Cu(2+), Cd(2+), Al(3+), V(4+), Hg(2+), Pd(2+), Au(3+), and Pt(4+) to provoke liquid crystalline (LC) phases in high molecular weight DNA was investigated. The alkali and alkaline earth metal ions provoked typical cholesteric/columnar structures, whereas transition metal ions precipitated DNA into solid/translucent gel-like aggregates. Heavy metal ions reduced viscosity of DNA solution, disrupting rigid, rod-like DNA structure necessary for LC textures.

Pyridine-catalyzed stereoselective addition of acyclic 1,2-diones to acetylenic esters: synthetic and theoretical studies of an unprecedented rearrangement.

A systematic study of the addition of various 1,2-acyclic diones to activated acetylenic esters catalyzed by pyridine under mild conditions is described. This reaction provides a new protocol for the stereoselective synthesis of 1,2-diaroyl maleates. The exclusive formation of the cis isomer is especially noteworthy.

Unusual addition of amines to C-2 of vinyl sulfone-modified-beta-D-pent-2-enofuranosyl carbohydrates: synthesis of a new class of beta-anomeric 2-amino-2,3-dideoxy-D-threo-pentofuranosides.

When 3-C-sulfonyl-pent-2-enofuranosides and 3-C-sulfonyl-hex-2-enofuranosides were reacted with primary and secondary amines, only the beta-anomeric methoxy group of the pent-2-enofuranoside did not cause any hindrance to incoming nitrogen nucleophiles. This resulted in the 'unusual' addition of amines, in which the diastereoselectivity of the reaction was overwhelmingly in favor of amino sugars of the D-arabino configuration. Selected products were desulfonylated to obtain a new class of beta-anomeric 2-amino-2,3-dideoxy-D-threo-pentofuranosides.

Studies on the synthesis and unusual behavior of vinyl sulfone-modified hexenopyranosylthymines.

Although vinyl sulfone-modified- (VSM) pent-2'-enofuranosyl nucleosides 2 and hex-2-enopyranosyl glycoside 4 are easily synthesized from the corresponding mesylated sulfones 1c and 3c, respectively, via an oxidation-mesylation-elimination route, the 3'-C-sulfonyl-hex-2'-enopyranosylthymine 11 is not obtained from 10 and a glycal derivative 12 is formed instead. On the other hand, 3'-C-sulfonyl-hex-3'-enopyranosylthymine 20 is easily synthesized from the mesylated sulfone 19. Again unlike the reaction patterns of VSM-pent-2'-enofuranosyl nucleosides 2 and hex-2-enopyranosyl glycosides 4 as Michael acceptors, the reactions of nucleophiles with 3'-C-sulfonyl-hex-3'-enopyranosylthymine 20 yielded a rearranged product 21 instead of Michael adducts.

Theoretical studies on the carcinogenicity of polycyclic aromatic hydrocarbons.

The distinct molecular regions of a set of 28 polycyclic aromatic hydrocarbons (PAHs) showing varying degrees of carcinogenic activity (CA) have been analyzed on the basis of their calculated molecular electrostatic potential (MESP) at B3LYP/6-31+G(d,p) level of theory. The MESP, being a property directly related to electron density, clearly distinguishes the electron dense centers in the molecule into K, L, M, and newly defined N regions. Further, a quantitative structure activity relationship (QSAR) model of carcinogenicity is developed using the volume of MESP lobes at the named regions for a set of 17 carcinogenic molecules with experimentally known CA index.

Role of structural water molecule in HIV protease-inhibitor complexes: a QM/MM study.

Structural water molecule 301 found at the interface of HIV protease-inhibitor complexes function as a hydrogen bond (H-bond) donor to carbonyl groups of the inhibitor as well as H-bond acceptor to amide/amine groups of the flap region of the protease. In this study, six systems of HIV protease-inhibitor complexes were analyzed, which have the presence of this "conserved" structural water molecule using a two-layer QM/MM ONIOM method. The combination of QM/MM and QM method enabled the calculation of strain energies of the bound ligands as well as the determination of their binding energies in the ligand-water and ligand-water-protease complexes.

Structure-activity relationship of a hemagglutinin from Moringa oleifera seeds.

The hemagglutinin from the seeds of Moringa oleifera (MoL) agglutinates human as well as rabbit erythrocytes; the affinity for the latter is almost 250 times more than that for the former. MoL was inhibited by glycoproteins namely thyroglobulin, fetuin and holotransferin indicating the complex sugar specificity of the lectin. The protein is a homodimer with molecular mass of 14kDa, subunits (7.

Steady state and time-resolved fluorescence studies of a hemagglutinin from Moringa oleifera.

The saccharide binding and conformational characterization of a hemagglutinin, a low molecular weight protein from the seeds of Moringa oleifera was studied using steady state and time resolved fluorescence. The lectin binds sugars LacNAc (K (a) = 1380 M(-1)) and fructose (K (a) = 975 M(-1)), as determined by the fluorescence spectroscopy. It has a single tryptophan per monomer which is exposed on the surface and is in a strong electropositive environment as revealed by quenching with iodide.

Quantitative assessment of the stereoelectronic profile of phosphine ligands.

The stereoelectronic profile of a variety of phosphine ligands (PR3) have been estimated using a combined approach of quantum mechanics (QM) and molecular mechanics (MM). The quantum mechanically derived molecular electrostatic potential minimum (Vmin) of a PR3 ligand at the phosphorus lone pair region provides a direct measure of the total electronic (Eeff) and steric effects (Seff) of the ligand. The difference between the Vmin of unsubstituted PH3 (Vmin(PH3)) and the Vmin of PR3 is considered as Eeff + Seff.

Oral lichen planus in relation to transaminase levels and hepatitis C virus.

Background: Elevation of transaminase levels was reported earlier in patients with oral lichen planus. The association between hepatitis C virus (HCV) and lichen planus had given positive and negative results. The controversies and uncertainties regarding the association of HCV and the liver function status (transaminase levels) in oral lichen planus inspired us to conduct this study.

Analysis of mitochondrial DNA sequences in childhood encephalomyopathies reveals new disease-associated variants.

Background: Mitochondrial encephalomyopathies are a heterogeneous group of clinical disorders generally caused due to mutations in either mitochondrial DNA (mtDNA) or nuclear genes encoding oxidative phosphorylation (OXPHOS). We analyzed the mtDNA sequences from a group of 23 pediatric patients with clinical and morphological features of mitochondrial encephalopathies and tried to establish a relationship of identified variants with the disease.

Methodology/principle Findings: Complete mitochondrial genomes were amplified by PCR and sequenced by automated DNA sequencing.

Bowman-Birk protease inhibitor from the seeds of Vigna unguiculata forms a highly stable dimeric structure.

Different protease inhibitors including Bowman-Birk type (BBI) have been reported from the seeds of Vigna unguiculata. Protease isoinhibitors of double-headed Bowman-Birk type from the seeds of Vigna unguiculata have been purified and characterized. The BBI from Vigna unguiculata (Vu-BBI) has been found to undergo self-association to form very stable dimers and more complex oligomers, by size-exclusion chromatography and SDS-PAGE in the presence of urea.

Water handling, sanitation and defecation practices in rural southern India: a knowledge, attitudes and practices study.

Diarrhoea and water-borne diseases are leading causes of mortality in developing countries. To understand the socio-cultural factors impacting on water safety, we documented knowledge, attitudes and practices of water handling and usage, sanitation and defecation in rural Tamilnadu, India, using questionnaires and focus group discussions, in a village divided into an upper caste Main village and a lower caste Harijan colony. Our survey showed that all households stored drinking water in wide-mouthed containers.

Insulin-like growth factor (IGF)-I, IGF-II and IGF-binding protein (IGFBP)-3 levels in Arab subjects with coronary heart disease.

Objective: Insulin-like growth factors (IGF-I, IGF-II) and their binding protein (IGFBP-3) may be risk markers for coronary heart disease (CHD). This study aimed to assess the levels and determinants of the serum levels of IGF-I, IGF-II and IGFBP-3 in Arab patients with established CHD.

Material And Methods: Two groups of subjects were matched for age, gender, BMI and waist-hip ratio (WHR): (i) CHD (n = 105), median age 51.

Photochromic dibenzobarrlenes: long-lived triplet biradical intermediates.

Upon exposure to UV light, the disubstituted dibenzobarrelene derivative 1a turns green in the solid phase and reverts back to its original pale-yellow color within several hours in the dark. The lifetime of the colored species in degassed benzene at room temperature is 37 +/- 2 s (Ea for decoloration is 14.5 +/- 0.