Synthesis, characterization and fluorescence studies of novel bi-phenyl based acrylate and methacrylate

4-[(1E)-3-(biphenyl-4-yl)buta-1,3-dien-1-yl]phenyl prop-2-enoate (ACH) and 4-[(1E)-3-(biphenyl-4-yl)buta-1,3-dien-1-yl]phenyl 2-methylprop-2-enoate (MCH) was synthesized from biphenyl in three steps and their structures were confirmed by elemental analysis, IR, NMR (1H, 13C, DEPT135, 1H-1H COSY, 1H-13C HSQC and 1H-13C HMBC) spectroscopic techniques. In this present study, various physicochemical characteristics we demonstrate solubility, color, absorbance and fluorescence property of novel biphenyl based acrylate and methacrylate measured in different solvents like benzene, dichloromethane, tetrahydrofuran, acetonitrile, dimethylsulfoxide and ethanol.

Development of a less toxic dichloroacetate analogue by docking and descriptor analysis

Dichloroacetate (DCA) is a synthetic compound that promotes the activity of pyruvate dehydrogenase (PDH) by inhibiting its repressor protein called pyruvate dehydrogenase kinase (PDHK). The activation of PDH leads to a reduction in ambient cellular lactate concentrations both in vitro and in vivo which contributes to the therapeutic use of DCA in the treatment of systemic lactic acidosis in humans. The therapeutic potential of DCA is now being explored in disorders that are accompanied by elevations of lactate concentration such as in hypoxic cancer cells. Yet conflicting evidence regarding its mutagenic potential has been a major setback in its clinical trials. Hence, docking and descriptor analysis of halogen substituted DCA analogues were performed to find out a drug candidate with less toxicity and better binding affinity than DCA. The Docking analysis was carried out using human PDHK isozyme 2, the physiological receptor for DCA. Bromo(iodo)acetate and Diiodoacetate were found out to be the plausible analogues of DCA from this study.

Robustness of the Drosophila segment polarity network to transient perturbations

Continuous and Boolean models for the Drosophila segment polarity network have shown that the system is able to maintain the wild-type pattern when subjected to sustained changes in the interaction parameters and initial conditions. Embryo development is likely to occur under fluctuating environmental conditions. Here, a well-established Boolean model is used to explore the ability of the segment polarity network to resist transient changes. Paths along which alternate unviable states are reached, and hence critical nodes whose state changes lead the system away from the wild-type state, are identified. It is found that the system appears to be more sensitive to changes that involve activation of normally inactive nodes. Through a simulation of the heat shock response, it is shown how a localised perturbation in one parasegment is more deleterious than a global perturbation affecting all parasegments. The sequence of events involved in the recovery of the system from a global transient heat shock condition is identified. Finally, these results are discussed in terms of the robustness of the system response.

Myocardial perfusion single photon emission computed tomography in asymptomatic diabetics

BACKGROUND

Coronary artery disease (CAD) is the most important cause of mortality in diabetic patients. Diabetes mellitus (DM) due to autonomic neuropathy leads to asymptomatic CAD. Hence, it is important to screen the patients with DM for CAD.

AIM

To study the prevalence of asymptomatic CAD by Myocardial Perfuision SPECT (Single Photon Emission Computed Tomography) (MPS) in diabetics.

METHODS

This prospective study included 88 asymptomatic patients (58 males and 30 females) of Type 2 DM of more than 5 years duration in the age group of 40-65 years. Risk factors like hypertension, dyslipidemia, smoking, family history of CAD and Body Mass Index > or = 25 kg/sq.m were assessed. All these patients underwent MPS study as two day standard protocol. Thirty eight patients underwent invasive Coronary Angiography (CAG) and stenosis greater than 50% was considered significant.

RESULTS

Abnormal perfusion was detected in 38 (43%) diabetics and 4 (11%) controls. A total of 81 perfusion defects were identified (19 fired and 62 reversible). CAG showed significant coronary stenosis in 26 (68.4%), insignificant in 8 (21%) and no stenosis in 4 (10.6%) patients. A total of 114 coronaries were analysed, significant stenosis in 67 (58.8%) coronaries, 21 (18.4%) had insignificant lesions and 26(22.8%) were normal. In comparison to CAG, MPS had sensitivity of 86.6% and specificity of 51%.

CONCLUSION

The Myocardial Perfusion SPECT is a sensitive diagnostic tool to identify ischemia in asymptomatic diabetics. MPS can be used as screening test for risk stratification. It has a prognostic value in predicting the outcome of CAD and can be useful for long-term follow up too.

LamB-mediated adherence of enteropathogenic Escherichia coli to HEp-2 cells

AIMS

To establish the role of maltoporin (LamB) in adherence of enteropathogenic Escherichia coli (EPEC) to epithelial cells in vitro.

METHODS AND RESULTS

Three strains, wild type (WT) EPEC, a maltoporin (LamB) mutant DeltalamB, and DH5alpha were used to study adherence to cultured HEp-2 cells. Mutant DeltalamB was found to be deficient in adherence compared to WT EPEC. Adherence of DeltalamB was restored to wild type levels when complemented with the cloned lamB gene. The non-adherent strain DH5alpha also adhered to HEp-2 cells when it harboured the cloned lamB gene. The LamB protein was isolated from WT EPEC by electroelution and antibodies were raised in rabbits. The specificity of the antibodies was analysed by Western blotting. Anti-LamB antiserum reduced adherence of WT EPEC to HEp-2 cells. The LamB protein was coated on latex beads and the beads adhered to HEp-2 cells. Anti-LamB antiserum prevented bead adherence to HEp-2 cells. Multiple sequence alignment showed that the L9 loop of EPEC LamB had four amino acids different from the L9 loop of LamB from several other related pathogens.

CONCLUSIONS

LamB serves as an alternative or additional adherence factor for EPEC.

SIGNIFICANCE AND IMPACT OF THE STUDY

Adherence is an important component of the pathogenesis of noninvasive pathogens like EPEC. A putative adhesin such as LamB, which has already been found to be co-expressed with virulence factor EspB may be a potential vaccine candidate for control of EPEC and related pathogens.

Forms and behaviour of vacuum emission electronic devices comprising diamond or other carbon cold cathode emitters

Nanocarbon-derived electron emission devices, specifically nanodiamond lateral field emission (FE) diodes and gated carbon nanotube (CNT) triodes, are new configurations for robust nanoelectronic devices. These novel micro/nanostructures provide an alternative and efficient means of accomplishing electronics that are impervious to temperature and radiation. For example, nitrogen-incorporated nanocrystalline diamond has been lithographically micropatterned to use the material as an electron field emitter. Arrays of laterally arranged 'finger-like' nanodiamond emitters constitute the cathode in a versatile diode configuration with a small interelectrode separation. A low diode turn-on voltage of 7V and a high emission current of 90 microA at an anode voltage of 70V (electric field of approx. 7V microm(-1)) are reported for the nanodiamond lateral device. Also, a FE triode amplifier based on aligned CNTs with a low turn-on voltage and a small gate leakage current has been developed.

Electrochemical destruction of p-chlorophenol and p-nitrophenol -- Influence of surfactants and anode materials

The electrochemical oxidative removal of p-chlorophenol and p-nitrophenol was studied by cyclic voltammetry (CV) and constant current electrolysis on commercially available graphite and titanium substrate insoluble anodes (TSIA). The effect of cationic cetyl trimethylammonium bromide (CTAB), anionic sodium dodecyl sulphate (SDS) and non-ionic polyoxyethylene(23)lauryl ether (Brij-35) surfactants, which prevent adherent film formation on the electrode surface were also studied. CV experiments indicate that p-chlorophenol exhibits a relatively higher tendency for film formation on graphite and that sodium chloride is a better medium for the destruction of phenols. The electrochemical oxidation of phenols under galvanostatic conditions in chloride medium with CTAB enhanced the detoxification process with significantly lower fouling effects on TSIA. The surfactants, however, did not improve phenol removal on graphite under identical experimental conditions. A charge of 2.5F per mol was found to be sufficient to achieve 44-48% removal of phenol on both the electrodes in the absence of the surfactants. A 55-65% removal was achieved in the presence of the cationic surfactant on the TSIA electrode. Phenol was removed as a low molecular weight polymer (MW approximately 4450).

Hallerborden Spatz disease

Hallervorden Spatz disease is a rare disorder characterized by progressive extrapyramidal dysfunction. We report a case of a 18 year old boy who presented with cervical dystonia, pigmentary retinal degeneration and MRI brain showing the "eye-of-the-tiger" appearance. Renamed recently as "Neurodegeneration with brain iron accumulation", we present this case for its rarity and interesting features.

Detection of virulence attributes of Burkholderia pseudomallei

BACKGROUND & OBJECTIVES

Melioidosis caused by Burkholderia pseudomallei is an emerging disease in India. This study examined the toxin activity of bacteria-free culture filtrate in three different cell lines (cytotoxic assay) and its effect on Caenorhabditis elegans (nematode toxicity assay). Endotoxic activity of the viable bacteria was also studied in C. elegans (co-culture killing assay).

METHODS

For toxin studies, serial doubling dilutions of unheated, heated crude and ultra filtrate of bacteria-free culture supernatants of B. pseudomallei were tested in 96-well microtitre plate containing confluent mono layers of McCoy, Hep-2 and HeLa cell lines. For the effects on C. elegans, the worms were exposed to heated and unheated bacteria-free culture supernatants in 24-well microtitre plate for 24h and then transferred to OP50 Escherichia coli lawn culture. The endotoxic activity of the live bacterium was studied by feeding the worms in the lawn culture of B. pseudomallei.

RESULTS

All the clinical isolates (n=38) produced cytotoxic changes in all the cell lines. No difference was observed in the cytotoxicity of unheated, heated and ultra-filtered culture supernatant. The septicaemic isolates were observed to produce cytotoxic changes in high dilutions (1:160) of culture filtrate. None of the unheated and heated crude filtrate had deleterious effect on C. elegans, while all the live bacteria were found to be lethal to the nematode.

INTERPRETATION & CONCLUSION

The culture supernatants, though produced cytopathic effect in various tissue cultures, failed to have any deleterious effect on the worms. However, live bacteria were lethal to the worms B. pseudomallei. Use of C. elegans model to detect virulence attributes of B. pseudomallei is recommended as an alternative to tissue culture methods as this can be carried out in laboratories where a tissue culture set up is not available.