α-Glucosidase Inhibitory Isomeric Corniculatolides from the Stems of the Indian Mangrove Plant, Xylocarpus granatum.

Three new isomeric corniculatolides (1, 2, and 3) with an unusual caffrane and isocorniculane framework, and five known metabolites were isolated from the chloroform extract of the stems of Xylocarpus granatum. The structures of the new metabolites were deduced as corniculatolide B (1), isocorniculatolide B (2), and corniculatolide C (3) by spectroscopic data analysis and a combination of chemical transformations and supported by single-crystal X-ray crystallographic data of 1 and 3. The isolated compounds were evaluated for their in vitro cytotoxicity and α-glucosidase (Saccharomyces cerevisiae) inhibitory potential. Compound 3 possessed α-glucosidase inhibitory activity with an IC50 value of 24.8 µM, whereas these rare macrolides showed no effect on the mammalian cancer cell lines MIAPaCa-2, DU145, MCF-7, and HTC-116.

Self-assembly, optical, thermal and electrochemical properties of bis-N-benzyl perylene diimide dye.

Flexible methylene containing N,N'-bis-(benzyl)-3,4,9,10-perylenebis(dicarboximide) (1) was synthesized. Self-assembled microstructures (hollow tubes, average length and width: 7.7 and 0.8 µm) of 1 were also prepared (T-1). Comparative studies of the optical, thermal and electrochemical properties of 1 and T-1 have been extensively carried out. The T-1 hallow tubes have shown extremely broad absorption in the near-infrared (300-800 nm) region (NIR) even in solution and intensified conductivity in the solid-state compared to 1. Under daylight and a UV lamp (365 nm), the emission colors of 1 are uniform pink and fluorescent yellow, respectively. Under the same conditions the colors of T-1 change to deep brown and glowing red, respectively. Two different isopotential points obtained through CV scans for 1 indicate the presence of two interconvertible chromophores within the system. The results clearly indicate that the anodic and cathodic processes are extremely intensified in the self-assembled T-1 structure.

Novel cycloartane triterpenoids from the Nepal native plant Caragana sukiensis.

A phytochemical study on the arial part of Caragana sukiensis resulted in the isolation of three new cycloartane triterpenoids 1-3 and their structures were fully established on the basis of detailed spectroscopic (especially 2D NMR and Mass) analysis. These new compounds possessed hemiacetal fused tetrahydropyran rings at C-15/C-16, while 2 and 3 also contains d-xylose moiety.

Synthesis of novel amide functionalized 2H-chromene derivatives by Ritter amidation of primary alcohol using HBF4·OEt2 as a mild and versatile reagent and evaluation of their antimicrobial and anti-biofilm activities.

A series of novel amide functionalized 2H-chromene derivatives 3 were prepared starting from ethyl-2-hydroxy-2-(trifluoromethyl)-2H-chromene-3-carboxylate 1 via sodium borohydride reduction followed by Ritter amidation using HBF4·OEt2 as a mild and versatile reagent. All the products 3 were screened for antimicrobial activity against various Gram-positive, Gram-negative bacteria and fungal strain. The promising derivatives such as 3f, 3g, 3k, 3l, 3m, 3n and 3o were further screened for minimum bactericidal concentration and bio-film inhibition activity and identified the potential ones. Among all the promising, compound 3g was more potent for antimicrobial, MBC and anti bio-film activities. The structure verses activity relationship of 3g revealed that the presence of two bromine atoms at sixth and R position promotes high activity.

Synthesis of a novel fluorescent amphiphilic chitosan biopolymer: photophysical and electrochemical behavior.

The present investigation describes for the first time, the synthesis and detailed characterization of a novel fluorescent and amphiphilic chitosan polymer (3) containing fluorescent peryleneimide chromophores for biomedical applications. The polymer 3 is moderately soluble in a wide range of organic solvents and aqueous solutions, unlike chitosan (2). The Mw of 3 and 2 determined by GPC were 467 kDa and 460 kDa, respectively. The photophysical and electrochemical properties measured in solution and solid states are engrossing. is soluble in the entire pH range and exhibits excimer emission above pH 5. In solution, 3 is electroactive but 2 is not. Whereas in the solid-state, 3 shows one quasi-reversible oxidation and reversible reduction step and 2 exhibits only one quasi-reversible oxidation step. Our results point out a new class of organic biopolymers that could yield promising potentials in many biomedical applications.

Type III Monteggia Fracture-dislocation with Radial Nerve Injury in Adults - A Case Report of two Cases.

Introduction: Uncommon complication of Monteggia fracture is associated PIN palsy. The PIN palsy following Monteggia fracture-dislocation is neuropraxias and will recover spontaneously. Case Report: Two cases who were diagnosed as Monteggia fracture-dislocation with PIN palsy and associated superficial branch of radial nerve injury - Power 0/5 and sensations 0/2 were taken up for surgery (open reduction internal fixation of fracture of ulna + closed reduction of radial head). By the end of 7 weeks, both sensory and motor power were fully recovered spontaneously in both the cases. Discussion: Most of the PIN injuries following Monteggia fracture-dislocation are neuropraxias and will recover spontaneously after closed reduction of radial head without any intervention to the nerve. The nerve needs to be intervened if there are no signs of recovery by 3 months. The time frame for the nerve to be intervened remains controversial. Conclusion: In both of our cases, the injury is probably proximal to the terminal division of radial nerve and the injuries were neuropraxias and have recovered spontaneously. Hence, we suggest not exploring the nerve in all cases with Monteggia fracture-dislocation immediately even when there is associated sensory deficit.

Development and validation of a highly sensitive LC-MS/MS method for quantitation of dexlansoprazole in human plasma: application to a human pharmacokinetic study.

A highly sensitive, specific and simple LC-MS/MS method was developed for the simultaneous estimation of dexlansoprazole (DEX) with 50 µL of human plasma using omeprazole as an internal standard (IS). The API-4000 LC-MS/MS was operated under multiple reaction-monitoring mode using electrospray ionization. A simple liquid-liquid extraction process was used to extract DEX and IS from human plasma. The total run time was 2.00 min and the elution of DEX and IS occurred at 1.20 min. This was achieved with a mobile phase consisting of 0.2% ammonia-acetonitrile (20:80, v/v) at a flow rate of 0.50 mL/min on an X-terra RP 18 (50 × 4.6 mm, 5 µm) column. The developed method was validated in human plasma with a lower limit of quantitation of 2 ng/mL for DEX. A linear response function was established for the range of concentrations 2.00-2500.0 ng/mL (r > 0.998) for DEX. The intra- and inter-day precision values for DEX met the acceptance criteria as per FDA guidelines. DEX was stable in the battery of stability studies, viz. bench-top, auto-sampler and freeze-thaw cycles. The developed assay method was applied to an oral bioequivalence study in humans.

A rapid LC-MS/MS method for quantitation of eszopiclone in human plasma: application to a human pharmacokinetic study.

A highly reproducible, specific and cost-effective LC-MS/MS method was developed for simultaneous estimation of eszopiclone (ESZ) with 50 µL of human plasma using paroxetine as an internal standard (IS). The API-4000 LC-MS/MS was operated under the multiple reaction-monitoring mode using the electrospray ionization technique. A simple liquid-liquid extraction process was used to extract ESZ and IS from human plasma. The total run time was 1.5 min and the elution of ESZ and IS occurred at 0.90 min; this was achieved with a mobile phase consisting of 0.1% formic acid-methanol (15:85, v/v) at a flow rate of 0.50 mL/min on a Discover C(18) (50 × 4.6 mm, 5 µm) column. The developed method was validated in human plasma with a lower limit of quantitation of 0.1 ng/mL for ESZ. A linear response function was established for the range of concentrations 0.10-120 ng/mL (r > 0.998) for ESZ. The intra- and inter-day precision values for ESZ were acceptable as per FDA guidelines. Eszopiclone was stable in the battery of stability studies, viz. bench-top, autosampler and freeze-thaw cycles. The developed assay method was applied to an oral bioequivalence study in humans.

A new tunable light-emitting and π-stacked hexa-ethyleneglycol naphthalene-bisimide oligomer: synthesis, photophysics and electrochemical properties.

An oligomer (3) containing flexible hydrophilic hexa(ethylene glycol) and hydrophobic naphthalene-bisimide chromophores has been synthesized by a one-step condensation reaction and its photophysical and electrochemical properties were investigated. 3 was characterized through the data from NMR, IR, UV-vis, GPC, DSC, TGA, elemental analysis and cyclic voltammetry. The average molecular weight (M(w)) of 3 was 4430 g mol(-1). Intrinsic viscosity was measured as 0.28 dL g(-1) in m-cresol at 25 °C. It has high thermal stability (T(d) = 325 °C). Interestingly, compound 3 shows excimer-like emission in all kinds of solvents. The band gap energy (E(g)), LUMO and HOMO energy values in nonpolar and polar protic solvents were 2.71 eV/3.12 eV, -3.69 eV/-3.88 eV and -6.40 eV/-7.00 eV for 3, respectively. The oligomer showed concentration and solvent dependent fluorescent color tunability. Remarkably, the fluorescent colors of the excimer emissions at 10(-6) M concentration in CHCl(3), DMF and MeOH are light yellow, light blue-yellow and strong blue, respectively, and become more intense at higher concentrations. The excimer emission color in CHCl(3) and DMF is fluorescent yellow and changed to green in MeOH at 10(-4) M concentration. 3 shows two reversible reduction steps at -1.103 and -1.457 V (vs. ferrocene/ferrocenium) in nonpolar solvent CH(2)Cl(2) and only one at -0.917 V in (50:50) CH(3)OH-CH(3)CN binary solvent mixture with higher reversibility. Strong blue-shifts of emission band were noted in protic solvents, which confirm the existence of a negative solvatochromism probably due to protonation. The strong solvent-dependent photophysical and electrochemical properties, including the large shift of excimer emission maximum reflecting self-assembly mediated through hydrogen bonding and π-stacking interactions, make the oligomer a potential candidate for various photo-sensing applications.

Development and validation of a highly sensitive LC-MS/MS method for simultaneous quantitation of nortriptyline and 10-hydroxynortriptyline in human plasma: application to a human pharmacokinetic study.

A highly sensitive and specific LC-MS/MS method has been developed for simultaneous estimation of nortriptyline (NTP) and 10-hydroxynortriptyline (OH-NTP) in human plasma (250 µL) using carbamazepine as an internal standard (IS). LC-MS/MS was operated under the multiple reaction-monitoring mode using the electrospray ionization technique. A simple liquid-liquid extraction process was used to extract NTP, OH-NTP and IS from human plasma. The total run time was 2.5 min and the elution of NTP, OH-NTP and IS occurred at 1.44, 1.28 and 1.39 min, respectively; this was achieved with a mobile phase consisting of 20 mm ammonium acetate : acetonitrile (20:80, v/v) at a flow rate of 0.50 mL/min on a HyPURITY C(18) column. The developed method was validated in human plasma with a lower limit of quantitation of 1.09 ng/mL for both NTP and OH-NTP. A linear response function was established for the range of concentrations 1.09-30.0 ng/mL (r > 0.998) for both NTP and OH-NTP. The intra- and inter-day precision values for NTP and OH-NTP met the acceptance as per FDA guidelines. NTP and OH-NTP were stable in a battery of stability studies, i.e. bench-top, auto-sampler and freeze-thaw cycles. The developed assay was applied to a pharmacokinetic study in humans.

Visually evoked oscillations of membrane potential in cells of cat visual cortex.

In response to visual stimulation, cells of the cat visual cortex fire rhythmically at frequencies between 30 and 60 hertz. This rhythmic firing can be synchronized among cells in widespread areas of the visual cortex. The visual stimulus conditions under which this process occurs suggest that the synchronization may contribute to the integration of information across broadly displaced parts of the visual field. An intricate mechanism must control the regularity of firing and its synchronization. In vivo whole-cell patch recordings from cells in area 17 have now shown that robust oscillations of membrane potential underlie the regularity of firing seen extracellularly. In the cells studied, the characteristics of the oscillations of membrane potential suggest that such oscillations are produced by rhythmic activity in synaptic inputs. These rhythmic synaptic inputs form the most likely mechanism for the synchronization of activity in neighboring cortical cells.

Linearity of summation of synaptic potentials underlying direction selectivity in simple cells of the cat visual cortex.

Intracellular recordings from simple cells of the cat visual cortex were used to test linear models for the generation of selectivity for the direction of visual motion. Direction selectivity has been thought to arise in part from nonlinear processes, as suggested by previous experiments that were based on extracellular recordings of action potentials. In intracellular recordings, however, the fluctuations in membrane potential evoked by moving stimuli were accurately predicted by the linear summation of responses to stationary stimuli. Nonlinear mechanisms were not required.

Quantification of montelukast, a selective cysteinyl leukotriene receptor (CysLT1) antagonist in human plasma by liquid chromatography-mass spectrometry: validation and its application to a human pharmacokinetic study.

A highly sensitive, rapid assay method has been developed and validated for the estimation of montelukast (MTK) in human plasma with liquid chromatography coupled to tandem mass spectrometry with electro spray ionization in the positive-ion mode. Liquid-liquid extraction was used to extract MTK and amlodipine (internal standard, IS) from human plasma. Chromatographic separation was achieved with 10 mM ammonium acetate (pH 6.4): acetonitrile (15:85, v/v) at a flow rate of 0.50 mL/min on a Discovery HS C(18) column with a total run time of 3.5 min. The MS/MS ion transitions monitored were 586.10 --> 422.10 for MTK and 409.20 --> 238.30 for IS. Method validation and clinical sample analysis were performed as per FDA guidelines and the results met the acceptance criteria. The lower limit of quantitation achieved was 0.25 ng/mL and linearity was observed from 0.25 to 800 ng/mL. The intra-day and inter-day precisions were 5.97-8.33 and 7.09-10.13%, respectively. This novel method has been applied to a pharmacokinetic study of MTK in humans.

Simultaneous estimation of four proton pump inhibitors--lansoprazole, omeprazole, pantoprazole and rabeprazole: development of a novel generic HPLC-UV method and its application to clinical pharmacokinetic study.

A highly selective, sensitive and accurate HPLC method has been developed and validated for the estimation of four proton-pump inhibitors (PPI), lansoprazole (LPZ), omeprazole (OPZ), pantoprazole (PPZ) and rabeprazole (RPZ), with 500 microL human plasma using zonisamide as an internal standard (IS). The sample preparation involved simple liquid-liquid extraction of LPZ, OPZ, PPZ and RPZ and IS from human plasma with ethyl acetate. The baseline separation of all the peaks was achieved with 0.1% triethylamine (pH 6.0):acetonitrile (72:28, v/v) at a flow rate of 1 mL/min on a Zorbax C(8) column. The total chromatographic run time was 11.0 min and the simultaneous elution of IS, OPZ, RPZ, PPZ and LPZ occurred at approximately 2.42, 4.45, 5.02 and 9.37 min, respectively. The method was proved to be accurate and precise at linearity range of 20.61-1999.79 ng/mL with a correlation coefficient (r) of >or=0.999. The limit of quantitation for each of the PPI studied was 20.61 ng/mL. The intra- and inter-day precision and accuracy values were found to be within the assay variability limits as per the FDA guidelines. The developed assay method was applied to a pharmacokinetic study in human volunteers.

Highly sensitive method for the determination of ropinirole with a lower limit of quantitation of 3.45 pg/mL in human plasma by LC-ESI-MS/MS: application to a clinical pharmacokinetic study.

A highly sensitive, rapid assay method has been developed and validated for the estimation of ropinirole (RPR) in human plasma with liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the positive-ion mode. A solid-phase process was used to extract RPR and citalopram (internal standard, IS) from human plasma. Chromatographic separation was operated with 0.2% ammonia solution:acetonitrile (20:80, v/v) at a flow rate of 0.50 mL/min on a Hypurity C(18) column with a total run time of 3.2 min. The MS/MS ion transitions monitored were 261.2 --> 114.2 for RPR and 325.1 --> 209.0 for IS. Method validation and clinical sample analysis were performed as per FDA guidelines and the results met the acceptance criteria. The lower limit of quantitation achieved was 3.45 pg/mL and the linearity was observed from 3.45 to 1200 pg/mL. The intra-day and inter-day precisions were in the range of 4.71-7.98 and 6.56-8.31%, respectively. This novel method has been applied to a pharmacokinetic study of RPR in humans.

Gas-liquid chromatography for fenvalerate residue analysis: in vivo alterations in the acetylcholinesterase activity and acetylcholine in different tissues of the fish, Labeo rohita (Hamilton).

The disruption of acetylcholinesterase activity (AChE) in the freshwater fish, Labeo rohita is demonstrated in the present study using acetylthiocholine iodide as substrate. L. rohita on exposure to lethal (6 microg/L) and sub-lethal (0.75 microg/L) concentrations of fenvalerate showed time- and dose-dependent inhibition in the activity of AChE, suggesting a decrease in the cholinergic transmission and consequent accumulation of acetylcholine (ACh) in the tissues (brain, gill, liver, and muscle) leading to continuous nerve impulses, causing prolonged muscle contraction which, as a consequence, causes paralysis and results in death. These also have lead to behavioral changes and create widespread disturbance in the normal neural physiology of the fish. Residue analysis using a gas-liquid chromatography technique (GLC) revealed that highest quantity of fenvalerate accumulated in gill followed by liver and muscle under lethal concentrations, whereas in sub-lethal concentrations muscle accumulated the highest concentration followed by gill and liver. The results suggest that in a biomonitoring program AChE activity can be a good diagnostic tool for assessing fenvalerate toxicity. The lipophilic nature of fenvalerate is of concern, since L. rohita is an important staple fish species, which may lead to the phenomenon of biomagnification.

An efficient copper-aluminum hydrotalcite catalyst for asymmetric hydrosilylation of ketones at room temperature.

A catalyst system consisting of a copper-aluminum hydrotalcite-chiral diphosphine ligand effects asymmetric hydrosilylation of several ketones, using polymethylhydrosiloxane (PMHS) as the stoichiometric reducing agent at room temperature, with moderate-to-excellent enantioselectivities. The catalyst is recovered by simple centrifugation, and the efficiency of the catalyst remains almost unaltered even after several cycles.

Clustering of perirhinal neurons with similar properties following visual experience in adult monkeys.

The functional organization of early visual areas seems to be largely determined during development. However, the organization of areas important for learning and memory, such as perirhinal cortex, may be modifiable in adults. To test this hypothesis, we recorded from pairs of neurons in perirhinal cortex of macaques while they viewed multiple complex stimuli. For novel stimuli, neuronal response preferences for pairs of nearby neurons and far-apart neurons were uncorrelated. However, after one day of experience with the stimuli, response preferences of nearby neurons became more similar. We conclude that specific visual experience induces development of clusters of perirhinal neurons with similar stimulus preferences.

Synthesis of novel pyrazolo[3,4-b]quinolinyl acetamide analogs, their evaluation for antimicrobial and anticancer activities, validation by molecular modeling and CoMFA analysis.

A series of novel alkyl amide functionalized 2,3-pyrazole fused quinoline derivatives 5, 6 and 7 have been prepared starting from quinoline-2(1H)one 1 in a series of steps. All the final products were screened for antibacterial activity, the promising lead compound 5r was identified with MIC values ranging between 3.9 and 7.8 µg/mL against different bacterial strains. Compound 5r also showed good antifungal and anti-biofilm activities against the tested panel of various fungal and bacterial strains. Compound 5r when treated on mature biofilms of S. aureus strain MLS16, showed increased levels of intracellular ROS accumulation suggesting its contribution to the bactericidal activity. All the compounds were also screened for anticancer activity against a panel of four human cancer cell lines. Based on these studies, compounds 5c, 5d, 5r and 7f were considered as promising and exhibited significant cytotoxicity with IC50 values of <15 µM. The biological activity data was further validated by molecular modeling and CoMFA studies.

Binding of sulfonyl-containing arylalkylamines at human 5-HT6 serotonin receptors.

Various sulfonyl-containing compounds (e.g. sulfonamides, sulfones) bind at human 5-HT6 serotonin receptors, but it has been difficult relating the binding mode(s) of such agents to one another, even though many possess a common SO2 moiety, to identify a common pharmacophore model(s). On the basis of the hypothesis that an ergoline-type conformation might be important for the binding of some sulfonamide-containing arylalkylamines, we prepared for examination at h5-HT6 receptors a series of compounds, including phenylethylamines 6, pyrroloethylamine 7, and phenylpiperazines 9. The results (with Ki values ranging from about 1 nM to >1000 nM) suggest that many of these agents likely bind in a related fashion, and structure-affinity studies indicate that the benzenesulfonamide portion of the phenylethylamine and phenylpiperazine analogues can be "reversed", abbreviated to a sulfone, and moved to an adjacent position with relatively little impact on affinity. Although a benzenesulfonamide (or related arylsulfonamide) group might be common to various 5-HT6 ligands, there appears to be some latitude with regard to the specific constitution and location of the sulfonamide moiety even within the same arylalkylamine structural framework. A pharmacophore model is presented to account for some of the current findings.