Fluorescence Investigations on Interactions between 7,8-benzo-4-azidomethyl Coumarin and Ortho- and Para-phenylenediamines in Binary Solvent Mixtures of THF and Water.

Fluorescence investigations on interactions between 7,8-benzo-4-azidomethyl coumarin (7BAMC) and quenchers ortho-phenylenediamine (OPD) and para-phenylenediamines (PPD) in binary solvent mixtures (THF + water) have been reported. UV-absorption study indicated a weak hydrophobic interaction between 7BAMC and the para isomer. NMR spectral studies indicated the presence of an interaction between 7BAMC and PPD. Magnitudes of the parameters associated with FRET, showed the presence of interactions between 7BAMC and PPD quencher is more predominant than OPD. Fluorescence quenching studies reveal the role of static and dynamic quenching pathways, depending upon Stern-Volmer constant, dielectric constant and dominant non-radiative processes. Binding equilibria analysis indicates a strong interaction between 7BAMC and PPD than OPD and formation of H-bonding. Based on the magnitudes of free energy, enthalpy change and entropy, bimolecular interaction process may be considered as spontaneous and hydrophobic.

Dual Fluorescence and Solvatochromic Study on 3-Acyl Coumarins.

Electronic absorption and emission spectra of 3-acetyl coumarin, 3-(bromoacetyl) coumarin and 3-(di bromoacetyl) coumarin have been recorded at room temperature in thirteen solvents with different polarities. Both ground and excited state dipole moments have been calculated for both locally excited and charge transfer transitions by using the solvatochromic method. Excited state dipole moments of all the three compounds are higher than their ground state values. DFT calculations have been profound to estimate their ground and excited state dipole moments. The estimated change in dipole moment by the application of microscopic solvent polarity parameter and bulk solvent polarity methods are in close agreement. Concentration dependent dual fluorescence has been observed in the emission spectra of all the three compounds. Graphical Abstract Dual fluorescence of 3-acetyl coumarin (I) in different solvents.

Association of dietary factors with severity of coronary artery disease.

BACKGROUND: Cardiovascular disease has taken epidemic proportions during past decades. Cardiovascular risk factors contribute to progression of coronary lesions, worsening the patient's prognosis. This study was planned to analyze the association of dietary factors with severity of coronary artery disease (CAD) in Indian patients. METHODS: Three hundred patients with known coronary disease above the age of 25 years were included in this study. Blood samples were collected for biochemical markers. Patients were stratified according to severity of CAD [number of vessel involved-single (SVD), double (DVD), triple (TVD)]. RESULTS: Mean age of the patient was 60.9 ± 12.4 years. Subjects with TVD, DVD, SVD in the study were 52.3%, 25.3% and 22.3% respectively. Patients with TVD had higher body mass index, triglycerides, HOMA-Insulin Resistance, hsCRP and lower high density cholesterol. Diabetes mellitus, hypertension and dyslipidemia were more common in TVD patients. Among macronutrients, patients with TVD had higher intake of carbohydrate and lower intake of protein and dietary fibers. There was no association of total fat intake with CAD, however, intake of palmitic acid was higher among patients with TVD. Intake of vitamins namely niacin, riboflavin, thiamine, B6, and vitamin-C decreased with increase in severity. With increase in severity of CAD, mineral intake (potassium, calcium, magnesium, phosphorus, sulfur, iron, chromium, copper, manganese, and zinc) decreased. CONCLUSIONS: Dietary factors are associated with severity of coronary artery disease. Low intake of protein, fiber, vitamins, minerals and high intake of carbohydrate and fat was associated with higher probability of having severe CAD.

Use of imipenem to detect KPC, NDM, OXA, IMP, and VIM carbapenemase activity from gram-negative rods in 75 minutes using liquid chromatography-tandem mass spectrometry.

Resistance to extended-spectrum ß-lactam antibiotics has led to a greater reliance upon carbapenems, but the expression of carbapenemases threatens to limit the utility of these drugs. Current methods to detect carbapenemase activity are suboptimal, requiring prolonged incubations during which ineffective therapy may be prescribed. We previously described a sensitive and specific assay for the detection of carbapenemase activity using ertapenem and liquid chromatography-tandem mass spectrometry (LC-MS/MS). In this study, we assessed 402 Gram-negative rods, including both Enterobacteriaceae and non-Enterobacteriaceae expressing IMP, VIM, KPC, NDM, and/or OXA carbapenemases, by using imipenem, meropenem, and ertapenem with LC-MS/MS assays. LC-MS/MS methods for the detection of intact and hydrolyzed carbapenems from an enrichment broth were developed. No ion suppression was observed, and the limits of detection for all three drugs were below 0.04 µg/ml. The sensitivity and specificity of meropenem and ertapenem for carbapenemase activity among non-Enterobacteriaceae were low, but imipenem demonstrated a sensitivity and specificity of 96% and 95%, respectively, among all Gram-negative rods (GNR) tested, including both Enterobacteriaceae and non-Enterobacteriaceae. LC-MS/MS allows for the analysis of more complex matrices, and this LC-MS/MS assay could easily be adapted for use with primary specimens requiring growth enrichment.

Association of dietary factors with insulin resistance and inflammatory markers in subjects with diabetes mellitus and coronary artery disease in Indian population.

BACKGROUND: Insulin resistance (IR) and inflammation have been implicated in pathogenesis of diabetes and cardiovascular disease. Dietary factors have been reported to be associated to insulin resistance and inflammation. Hence, we studied the association of dietary factors with IR and inflammation in known patients with diabetes mellitus and coronary artery disease with the hypothesis that carbohydrate and fat will be positively; and protein, fiber and mineral will be negatively associated with IR and inflammatory markers. METHODS: Three hundred patients (M: 216; F: 84, age: 25-92) who had coronary disease on angiography were included in this study consecutively. All patients were evaluated for anthropometry and cardiovascular risk factors, and blood samples were collected for biochemical and inflammatory markers. Nutrition assessment was done once at the time of recruitment, based on 24h dietary recall. RESULTS AND CONCLUSIONS: Diabetic patients had significantly lower protein and total dietary fiber intake as compared to non diabetics. Diabetic patients had lower intake of vitamin A, riboflavin and vitamin B12. There was significantly lower intake of minerals by diabetic patients. Dietary carbohydrate and fat were positively, and protein and dietary fiber intakes were negatively correlated with HOMA-IR and IL-6. There was no correlation of individual amino acids with HOMA-IR but showed strong negative correlation with inflammatory markers (hsCRP; IL-6 and TNF-α). Intake of vitamins and minerals was negatively correlated with HOMA-IR and inflammatory markers. There is a strong correlation between dietary factors, insulin resistance and inflammatory markers.

Computer Aided Prediction of Biological Activity Spectra: Study of Correlation between Predicted and Observed Activities for Coumarin-4-Acetic Acids.

Coumarin-4-acetic acids have been synthesized from various phenols and citric acid under Pechmann cyclisation conditions. All the compounds have been evaluated for antiinflammatory and analgesic activity in acute models. Compounds have also been evaluated for their ulcerogenic potential. Using the computer program, prediction of activity spectra for substances, prediction results and their Pharma Expert software, we have found a correlation between the observed and predicted antiinflammatory activity.

Effect of nitro groups on the photo physical properties of benzimidazolone: a solvatochromic study.

Electronic absorption and fluorescence spectra of mono, di, and tri-nitro benzimidazolones are measured at room temperature (298 K) in nine solvents with different polarities and the observed shifts are compared with benzimidazolone. Ground and excited state electric dipole moments are determined using the solvatochromic method based on the bulk solvent properties, F(1)(ε, n) and F(2)(ε, n). A reasonable agreement is observed between the experimental and ab initio dipole moments. Change in dipole moment is also determined using the solvatochromic method based on the microscopic solvent polarity parameter, (E(T)(N)), which considers the polarization changes due to hydrogen bonding in different solvents. It has been observed that the correlation of the solvatochromic Stokes shifts with the parameter (E(T)(N)), is superior to that derived using bulk solvent polarity functions for all the benzimidazolones reported in the present study. Calculated difference between excited state and ground state dipole moments seems to be a good measure of the effect of nitro group when correlated with (E(T)(N)).

Vibrational and ab initio studies of 3-acetyl-6-bromocoumarin and 3-acetyl-6-methylcoumarin.

Infrared absorption and Raman spectra (3500-50 cm(-1)) of 3-acetyl-6-bromocoumarin and 3-acetyl-6-methylcoumarin have been measured and interpreted, aided by electronic structure calculations at RHF and B3LYP using 6-31(d, p) basis set. It has been determined that the rotation of the acetyl group with respect to the coumarin ring results in three conformers--two trans and one cis--for each molecule, with one trans conformer being the most stable in both cases. There are significant changes in the vibrational structure as characterized by positions and intensities of certain modes in going from 3-acetyl-6-bromocoumarin to 3-acetyl-6-methylcoumarin. The carbonyl stretching mode of the pyrone ring is stable in both molecules whereas the same mode in acetyl groups is not. Ring stretching vibrations are coupled to C-H in-plane bending vibrations. Down-shifting of frequencies of methyl vibrations in acetyl group occurs vis-à-vis methyl vibrations in 3-acetyl-6-methylcoumarin. A strong Raman band at 126 cm(-1) in both molecules is structure-independent non-genuine mode, correlated to lattice vibrations in the solid phase.

Vibrational spectra, normal modes, ab initio and DFT calculations for 6-Chloro- and 7-Chloro-4-bromomethylcoumarins.

Vibration spectral measurements - Infrared (4000-400 cm(-1)) and Raman (3500-50 cm(-1)) spectra - have been made for the solid samples of 6-Chloro- and 7-Chloro-4-bromomethylcoumarins. Ground electronic state energies, equilibrium geometries, harmonic vibrational spectra and normal modes have been computed using ab initio - RHF/6-31G* - and DFT - B3LYP/6-31G* levels of theory. The optimization yielded three structures for each molecule, with one being a transition state structure. Of the remaining two conformers, one belongs to C(s) symmetry and the other belongs to C(1), the latter being the most stable one. The optimized dihedral angle for -CH(2)Br group is 111 degrees in agreement with X-ray diffraction results reported for the similar molecular systems. Assignment of all the observed spectral bands has been proposed. The absorptions show band pattern revealing isomer characteristics and vibrational coupling in varying degrees; the Raman spectra show structural changes associated with the rings as well as lattice modes.

Synthesis, structure and DNA cleavage studies of coumarin analogues of tetrahydroisoquinoline and protoberberine alkaloids.

Novel molecular matrices have been derived from coumarin-4-acetic acids and beta-phenylethylamines using the Bischler-Napieralski protocol which has led to the synthesis of analogues of tetrahydropapaverine in which the dimethoxybenzene moiety has been replaced by substituted coumarins. One carbon homologation has led to cyclization at the C3 position of coumarin generating the protoberberine skeleton. Structures have been confirmed by diffraction studies. The results showed that compounds 6e, 6f, 7e and 7f were found to be very effective against DNA samples of Gram positive bacterium Staphylococcus aureus and fungus Aspergillus niger.

Vibrational assignments for 7-methyl-4-bromomethylcoumarin, as aided by RHF and B3LYP/6-31G* calculations.

Infrared (4000-400 cm(-1)) and Raman (3500-50 cm(-1)) spectral measurements have been made for the solid sample of 7-methyl-4-bromomethylcoumarin. Electronic structure calculations at RHF/6-31G* and B3LYP/6-31G* levels of theory have been performed, giving equilibrium geometries, harmonic vibrational spectra and normal modes. Different orientations of bromomethyl group have yielded only two conformers, of which the most stable one lying lower from the other conformer by approximately 7.99 kJ/mol, is non-planar with no symmetry. A complete assignment of the vibrational modes, aided by the calculations, has been proposed. Coupled vibrations are manifest in many modes. Some spectral features, compared to 6-methyl-4-bromomethylcoumarin, show changes across both IR and Raman spectra, involving mainly skeletal vibrations, and to a lesser degree, methyl and bromomethyl vibrations. Low-frequency vibrations below 150 cm(-1) are assigned to lattice modes.

Synthesis and anti-inflammatory evaluation of methylene bridged benzofuranyl imidazo[2,1-b][1,3,4]thiadiazoles.

A series of 6-substituted and 5,6-disubstituted 2-(6-methyl-benzofuran-3-ylmethyl)-imidazo[2,1-b][1,3,4]thiadiazoles have been synthesized. The new compounds have been tested for their in vivo analgesic, anti-inflammatory activities. Qualitative SAR studies indicate that the chloro substitution in the imidazole ring and introduction of formyl group at C-5 position of the imidazole ring increased the anti-inflammatory and analgesic activity. All the newly synthesized compounds have been characterized by spectral data and ORTEP diagram of one of the intermediates 6-(4-chlorophenyl)-2-(6-methyl-benzofuran-3-ylmethyl)-5-morpholin-4-ylmethyl imidazo[2,1-b][1,3,4]thiadiazole is reported herein.

Vibrational assignments and electronic structure calculations for 3-acetylcoumarin.

Laser Raman (3500-50 cm(-1)) and IR (4000-400 cm(-1)) spectral measurements have been made on the laboratory prepared solid 3-acetylcoumarin. Molecular electronic energy, equilibrium geometrical structure and harmonic vibrational spectra have been computed at the RHF/6-31G(d,p) and B3LYP/6-31G(d,p) levels of theory. A complete vibrational assignment aided by the theoretical harmonic frequency analysis has been proposed. The B3LYP/6-31G(d,p) geometrical parameters, and frequencies of the C=O in the pyrone and acetyl group are in good agreement with experiment. The difference in the frequencies due to the two carbonyl groups, 50 cm(-1), which is attributed to the conjugation effect, is accounted for by the B3LYP to be 56cm(-1).

Simultaneous downregulation of CDK inhibitors p18(Ink4c) and p27(Kip1) is required for MEN2A-RET-mediated mitogenesis.

Multiple endocrine neoplasia type 2A (MEN2A) is predisposed by mutations in the RET proto-oncogene. Low expression of the cyclin-dependent kinase inhibitor (CDKI) p27(Kip1) is present in thyroid tumors, and recent evidence demonstrates p27 downregulation by the active RET mutant, RET/PTC1, found in papillary thyroid carcinoma. This implicates decreased p27 activity as an important event during thyroid tumorigenesis. However, p27(-/-) mice develop MEN-like tumors only in combination with loss of another CDKI, p18(Ink4c). This suggests that p18 and p27 functionally collaborate in suppression of tumorigenesis, that loss of both is critical in the development of MEN tumors and that both p18 and p27 are regulated by RET. We report that induction of the constitutively active MEN2A-specific RET mutant, RET2A(C634R), correlates with reduced p18/p27, and elevated cyclin D protein levels, leading to increased CDK activity, increased pRb phosphorylation and proliferation under growth arrest conditions. Mechanistically, RET2A represses p18/p27 mRNA levels while elevating cyclin D1 mRNA levels. RET2A expression also correlates with decreased p27 protein stability. RET2A-mediated regulation of p18 and p27, but not of cyclins D1 and D2, requires functional mitogen-activated protein kinase signaling. Additionally, RET2A-dependent p18 repression is required and sufficient to increase cell proliferation. Perhaps most significantly, MEN2A adrenal tumors also display these changes in cell cycle expression profile, demonstrating the biological relevance of our cell culture studies. Our results demonstrate for the first time that RET2A regulates p18, and suggest that loss of not only p27 but also of p18 expression is a key step in MEN tumorigenesis.

Fourier transform-infrared and Raman spectra, ab initio calculations and assignments for 6-methyl-4-bromomethylcoumarin.

Fourier transform-infrared (4000-400 cm-1) and Raman (3500-50 cm-1) spectral measurements have been made for 6-methyl-4-bromomethylcoumarin. Equilibrium structures, harmonic vibrational frequencies, infrared intensities, and depolarization ratios have been computed at RHF/6-31G* and B3LYP/6-31G* levels of theory. Twisting CH2Br moiety in the geometry optimization leads to the most stable conformer lacking symmetry (C1). This is reflected in the richness of bands in the experimental spectra. A complete assignments of the bands, aided by the ab initio calculations, has been proposed for the 6-methyl-4-bromomethylcoumarin. Due to lack of symmetry, several normal vibrations have been found to be mixed ones.

Synthesis and in vivo analgesic and anti-inflammatory activity of some bi heterocyclic coumarin derivatives.

Sets of coumarinyl ethers having chromone, benzofuranyl and 4-hydroxy coumarins (4, 5, 6) were prepared and tested for analgesic and antiinflammatory activity. The 4-(4'-acetyl-3'-hydroxy-phenoxymethyl)-coumarin 3 were synthesised by the reaction of 4-bromo methyl coumarin with 2, 4-dihydroxy acetophenones, were found to less active. Further compound 3 having the ortho hydroxy moiety was cyclised to chromones 4 and benzofurans 5 were found to enhance the analgesic and anti-inflammatory activity. The cyclisation to 4-hydroxy coumarin 6 was found to be reducing the anti-inflammatory and analgesic activity in this series. These newly synthesized compounds were found to produce less toxicity and less ulcerogenic effects.

Diagnostic role of stool culture & toxin detection in antibiotic associated diarrhoea due to Clostridium difficile in children.

BACKGROUND & OBJECTIVE: Mere diagnosis of Clostridium difficile by culture does not help in the diagnosis of antibiotic associated diarrhoeae (AAD) due to C. difficile. Detection of toxins A and B form the mainstay in the diagnosis of AAD due to C. difficile. This study was undertaken to find out the role of stool culture and toxin detection in the diagnosis of AAD due to C. difficile. As there are very few documented reports from India about AAD due to C. difficile in children in the age group of 5-12 yr, this age group was selected. METHODS: Faecal samples were collected from 250 hospitalized children in the age group of 5-12 yr who developed diarrhoea on receiving antibiotics for different medical problems for more than five days duration. Also faecal samples of 250 age and sex matched controls were collected. Culture for C. difficile was done on cycloserine cefoxitin fructose egg yolk agar (CCFA) and colonies were identified by standard laboratory techniques. ELISA for toxins A and B detection and tissue culture on HeLa cells for toxin B detection were also done. RESULTS: Overall positivity was 18 per cent in this study group compared to the controls (P<0.001). Maximum positive cases were in 5-8 yr age group (84.4%). Severe diarrhoea, liquid stool with mucus and blood, faecal leucocytes >5/high power field, altered flora and presence of Gram-positive bacilli with oval subterminal spores on Gram stain were sensitive predictors for diagnosis of AAD due to C. difficile. Amongst positive cases, 68.9 per cent responded to discontinuation of antibiotics and 31.1 per cent to metronidazole therapy. INTERPRETATION & CONCLUSION: C. difficile was an important pathogen responsible for antibiotic associated diarrhoea (AAD) in children of 5-12 yr age group. Conservative use of antibiotics would be beneficial to decrease the incidence of AAD.

Multiple giant congenital melanocytic nevi with central nervous system melanosis.

A case of multiple giant congenital melanocytic naevi in whom central nervous system melanosis was detected at 6 weeks of age is described. The infant was asymptomatic, but presence of risk factors such as multiple naevi, giant naevi and naevi on scalp and posterior axial location prompted a magnetic resonance imaging study of the brain. To our knowledge, neurocutaneous melanosis at such a young age has not been reported in Indian literature.