PHYTOCHEMICAL SCREENING AND CHARACTERIZATION OF VOLATILE COMPOUNDS BY GAS CHROMATOGRAPHY-MASS SPECTROMETRY FROM “NEPHROLEPIS EXALTATA”

Objective: Plants contain various types of phytochemicals with different solvent as per solvation properties, depending on their polarity. The goal of this analysis is to compare the effects of different solvents on the phytochemical profile and the characterization of different volatile bioactive compounds of Nephrolepis exaltata, a typical fern belonging to pteridophyte species. Methods: For the screening of phytochemical, a sequential extraction was carried out using different solvent systems namely methanol (MeOH), chloroform, carbon tetrachloride, hexane, and ethyl acetate (EtAc). A varied range of phytochemicals was found in the extracts. The volatile components were analyzed using the hyphenated technique gas chromatography-mass spectrometry (GC-MS). Results: All the extracts were found to be rich in alkaloids, whereas phenols and Phytosterols were extracted only in MeOH. The MeOH extract of the fern presented positive results for six phytochemical tests and the n-Hexane (nH) extract presented positive results for seven phytochemical tests. The present investigation on the plant N. exaltata aimed to prove that pteridophytes should have various kinds of bioactive phytochemicals and the selection of solvent for extraction of phytochemicals should be based on the target compounds. Conclusion: From the % yield of different extract, it can be concluded that some the bioactive phytochemicals are more soluble in more polar solvents such as MeOH, some are soluble in moderate solvents like EtAc and mostly non-polar organic molecules can be extracted using non-polar solvents like nH. The GC-MS characterization indicates the presence of different fatty compounds and sterols in the plant extract

Cholinergic neural activity directs retinal layer-specific angiogenesis and blood retinal barrier formation.

Blood vessels in the central nervous system (CNS) develop unique features, but the contribution of CNS neurons to regulating those features is not fully understood. We report that inhibiting spontaneous cholinergic activity or reducing starburst amacrine cell numbers prevents invasion of endothelial cells into the deep layers of the retina and causes blood-retinal-barrier (BRB) dysfunction in mice. Vascular endothelial growth factor (VEGF), which drives angiogenesis, and Norrin, a Wnt ligand that induces BRB properties, are decreased after activity blockade. Exogenous VEGF restores vessel growth but not BRB function, whereas stabilizing beta-catenin in endothelial cells rescues BRB dysfunction but not vessel formation. We further identify that inhibiting cholinergic activity reduces angiogenesis during oxygen-induced retinopathy. Our findings demonstrate that neural activity lies upstream of VEGF and Norrin, coordinating angiogenesis and BRB formation. Neural activity originating from specific neural circuits may be a general mechanism for driving regional angiogenesis and barrier formation across CNS development

Dendritic ion channel trafficking and plasticity.

Dendritic ion channels are essential for the regulation of intrinsic excitability as well as modulating the shape and integration of synaptic signals. Changes in dendritic channel function have been associated with many forms of synaptic plasticity. Recent evidence suggests that dendritic ion channel modulation and trafficking could contribute to plasticity-induced alterations in neuronal function. In this review we discuss our current knowledge of dendritic ion channel modulation and trafficking and their relationship to cellular and synaptic plasticity. We also consider the implications for neuronal function. We argue that to gain an insight into neuronal information processing it is essential to understand the regulation of dendritic ion channel expression and properties

Laser Ultrasonic Characterisation of Membranes for Use as MEMS

Germanium (Ge) on Silicon (Si) has the potential to produce a wide variety of devices, including sensors, solar cells and transistors. Modification of these materials so that a suspended membrane layer is formed, through removing regions of the Si substrate, offers the potential for sensors with a more rapid response and higher sensitivity. Such membranes are a very simple micro-electronic mechanical system (MEMS). It is essential to ensure that the membranes are robust against shock and vibration, with well-characterised resonant frequencies, prior to any practical application. We present work using laser interferometry to characterise the resonant modes of membranes produced from Ge or silicon carbide (SiC) on a Si substrate, with the membranes typically having sub-mm lateral dimensions. Two-dimensional scanning of the sample enables visualisation of each mode. The stress measured from the resonant frequencies agrees well with that calculated from the growth conditions. SiC is shown to provide a more robust platform for electronics, while Ge offers better resonant properties. Defects on the membranes alter the resonant mode, and this offers a potential technique for characterising production quality or lifetime testing for the MEMS produced

An observational prospective study of topical acidified nitrite for killing methicillin-resistant Staphylococcus aureus (MRSA) in contaminated wounds

Background Endogenous nitric oxide (NO) kills bacteria and other organisms as part of the innate immune response. When nitrite is exposed to low pH, NO is generated and has been used as an NO delivery system to treat skin infections. We demonstrated eradication of MRSA carriage from wounds using a topical formulation of citric acid (4.5%) and sodium nitrite (3%) creams co-applied for 5 days to 15 wounds in an observational prospective pilot study of 8 patients. Findings Following treatment with topical citric acid and sodium nitrite, 9 of 15 wounds (60%) and 3 of 8 patients (37%) were cleared of infection. MRSA isolates from these patients were all sensitive to acidified nitrite in vitro compared to methicillin-sensitive S. aureus and a reference strain of MRSA. Conclusions Nitric oxide and acidified nitrite offer a novel therapy for control of MRSA in wounds. Wounds that were not cleared of infection may have been re-contaminated or the bioavailability of acidified nitrite impaired by local factors in the tissue

Preemptive use of Small Dose Fentanyl Suppresses Fentanyl Induced Cough

ABSTRACT Backgroun

A novel method for spectrophotometric determination of pregabalin in pure form and in capsules

<p>Abstract</p> <p>Background</p> <p>Pregabalin, a γ-amino-n-butyric acid derivative, is an antiepileptic drug not yet official in any pharmacopeia and development of analytical procedures for this drug in bulk/formulation forms is a necessity. We herein, report a new, simple, extraction free, cost effective, sensitive and reproducible spectrophotometric method for the determination of the pregabalin.</p> <p>Results</p> <p>Pregabalin, as a primary amine was reacted with ninhydrin in phosphate buffer pH 7.4 to form blue violet colored chromogen which could be measured spectrophotometrically at λ_max402.6 nm. The method was validated with respect to linearity, accuracy, precision and robustness. The method showed linearity in a wide concentration range of 50-1000 μg mL^-1with good correlation coefficient (0.992). The limits of assays detection was found to be 6.0 μg mL^-1and quantitation limit was 20.0 μg mL^-1. The suggested method was applied to the determination of the drug in capsules. No interference could be observed from the additives in the capsules. The percentage recovery was found to be 100.43 ± 1.24.</p> <p>Conclusion</p> <p>The developed method was successfully validated and applied to the determination of pregabalin in bulk and pharmaceutical formulations without any interference from common excipients. Hence, this method can be potentially useful for routine laboratory analysis of pregabalin.</p

Sensor Development for High Temperature Viscosity Measurement

In previous years, we have presented several results on viscosity measurements using conventional and laser ultrasound techniques [1,2,3]. These results are based on experiments conducted at room temperature. The principle[1], in essence, is to launch ultrasonic shear waves at the interface of a solid and a viscous fluid. The amplitude and phase of the reflected waves were correlated to the viscosity of the fluid.</p