Early Diagnosis of Diabetes through the Eye

Diabetes mellitus is a metabolic disorder characterized by high blood sugar levels which give rise to complications in the eye, kidneys and the brain. Diabetes triggers the development of ocular diseases like diabetic retinopathy and cataracts which are the leading cause of blindness around the world. The most common method for the diagnosis of diabetes involves measuring the blood sugar levels in the body. One major disadvantage of this method is the fluctuating blood sugar levels which contribute to false negative results. This leads to delay in treatment, eventually causing permanent damage to the organs. Therefore, diagnosis of diabetes at an early stage is very crucial. One biomarker for diabetes related diseases is the formation of Advanced Glycation End‐products (AGEs) that result from the Maillard reaction of proteins with glucose. α‐crystallin in the ocular lens is a small heat shock protein with no protein turnover and hence acts as a record for post‐translational modifications especially glycation which forms AGEs. We have used steady state and time resolved fluorescence measurements to study the spectroscopic changes in α‐crystallin with increase in time of glycation and the intact lenses from diabetic and nondiabetic donors. Overall, this study was focused on developing a noninvasive diagnostic tool for early detection of diabetes mellitus.     

Kinetics and mechanism of the oxidation of glycolaldehyde by tetrachloroaurate(III)

The kinetics of the reaction between glycolaldehyde (GA) and tetrachloroaurate(III) in acetic acid-sodium acetate buffer has been studied. The reaction is first-order with respect to [Au^III] as well as [GA]. Both H⁺ and Cl⁻ ions retard the rate of reaction. AuCl₄⁻, AuCl₃(OH₂), and AuCl₃(OH)⁻ are the reactive species of gold(III) with gradually increasing reactivity. A reaction mechanism involving two-electron transfer rate determining steps has been proposed. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet: 30: 613–619, 1998     

Relaxation of the folding of globulin around heme of hemoglobin of Homo sapiens by the food-grade additive molecule chlorophyllin

Abstract  

Binding of chlorophyllin (Chln), a food-grade additive molecule with hemoglobin (Hb), has been studied by photophysical and photochemical methods with a view to unravel the biochemical transport pathway of it. The binding affinity constant and binding sites between Chln and Hb are determined and found to be 3.3 × 10⁵ M⁻¹ and 15 (on tryptophan basis), respectively. Fluorimetric quenching experiments entail that Chln is bound in the vicinity of the tryptophan residue of Hb. Circular dichroism studies suggest that Chln induces a change in the α-helical content of Hb. Chlorophyllin is bound in the vicinity of the tryptophan residue of hemoglobin, which has been confirmed from spectrofluorimetric studies, when a quenching in the tryptophan fluorescence occurs because of the chlorophyllin-induced exposure of the tryptophan residue to hydrophillic zone. The cyclic voltammetric studies indicate that the redox reaction of Fe^II of Hb is inhibited shielding of it by the Chln molecule.     

Cryptand derived fluorescence signaling systems for sensing Hg(II) ion: A comparative study

Two laterally non-symmetric aza-oxa cryptands have been derivatized with the electron-withdrawing fluorophore, 7-nitrobenz-2-oxa-1,3-diazole to obtain the corresponding mono-, bis- and tris-products. In each case, no appreciable emission is observed when the fluorophore is excited due to an efficient photoinduced intramolecular electron transfer (PET) from the lone pair on nitrogen present in the bridges. In the presence of a number of transition and heavy metal ions, their emission characteristics change. The electron-withdrawing ability of the fluorophore drastically alters the binding ability of the cryptand such that Hg(ii) affords largest enhancement of fluorescence. In contrast, mono-, bis- and tris-anthryl (electron-donating) derivatives of these cryptands do not exhibit any selectivity towards Hg(ii) and affords low fluorescence enhancement. Also, the difference in cavity dimension of the o-cryptand and m-cryptand plays a crucial role in terms of selectivity.     

An organocatalytic rearrangement of 2-(N-alkyl-/aryl-)amino-4-oxo-4H-1-benzopyran-3-carbaldehyde

2-(Arylamino)-4-oxo-4H-1-benzopyran-3-carbaldehyde rearranges to 4-oxo-4H-1-benzopyran-3-carbanilide when treated with glycine in the presence of formalin, but under similar conditions 2-(alkylamino)-4-oxo-4H-1-benzopyran-3-carbaldehyde rearranges to 3-alkylaminomethylenechroman-2,4-dione.     

Detection of miRNA in Live Cells by Using Templated RuII‐Catalyzed Unmasking of a Fluorophore

Reactions templated by cellular nucleic acids are attractive for nucleic acid sensing or responsive systems. Herein we report the use of a photocatalyzed reductive cleavage of an immolative linker to unmask a rhodamine fluorophore, and its application to miRNA imaging. The reaction was found to proceed with a very high turnover (>4000) and provided reliable detection down to 5 pM of template by using γ‐serine‐modified peptide nucleic acid (PNA) probes. The reaction was used for the selective detection of miR‐21 in BT474 cells and miR‐31 in HeLa cells following irradiation for 30 min. The probes were introduced by using reversible permeation with streptolysin‐O (SLO) or a transfection technique.     

Effect of Glycerol in the Polymerization of Methyl Methacrylate by Mn(III) Acetate

The kinetics of the mechanism of the polymerization of methyl methacrylate initiated by the glycerol/Mn(III) acetate redox system has been investigated in aqueous sulfuric acid medium in the temperature range of 40 to 50 °C. The effects of glycerol, methyl methacrylate, metal ion, acetic acid, and sulfuric acid on the rates of polymerization have been studied. One striking observation is that the increase in monomer concentration steadily decreases the rate of polymerization, contrary to what was observed in the case of acrylonitrile. On the basis of these observations, an appropriate kinetic scheme and rate expression have been developed.     

Aza-Michael Addition of Amines to α,β-Unsaturated Compounds Using Molecular Iodine as Catalyst

Aza-Michael adducts are obtained in very good yields by the conjugate addition of aliphatic amines to α,β-unsaturated compounds using molecular iodine as catalyst in dichloromethane at room temperature. Aromatic amines were found to be reactive under reflux in toluene.     

Crystal structure of a liquid crystal non‐symmetric dimer: cholesteryl 4‐[4‐(4‐n‐butylphenylethynyl)phenoxy]butanoate

The crystal structure of cholesteryl 4‐[4‐(4‐n‐butylphenylethynyl)phenoxy]butanoate [phase sequence: Cr 155°C (46.1?J?g^?1) SmA 186.8°C (1.5?J?g^?1) TGB‐N* 204.7 (6?J?g^?1) I] has been solved from single crystal X‐ray diffraction data. The compound crystallizes in the monoclinic space group P2₁ with unit cell parameters: a?=?13.129(2), b?=?9.3904(10), c?=?17.4121(8)?Å, β?=?92.790(7)°, Z?=?2. The structure has been solved by direct methods and refined to R?=?0.0606 for 3?250 observed reflections. The bond distances and angles are in good agreement with the corresponding values for compounds containing phenyl and cholesterol moieties. The phenyl rings A and B are planar. The dihedral angle between the least‐squares planes of the two phenyl rings is 28°. The cholesterol moiety has the usual structure: the C and E rings have chair conformations, and the D and F rings adopt half‐chair conformations. The molecules in the unit cell are arranged in an antiparallel manner. The crystal structure is stabilized by an intermolecular C–H…O contact of 2.989(10)?Å.