Ultrasensitive detection of L-cysteine using gold-5-amino-2-mercapto-1,3,4-thiadiazole core-shell nanoparticles film modified electrode.

We are reporting the selective, sensitive and stable determination of L-cysteine (CY) at physiological pH (pH=7.2) using a gold-aminomercaptothiadiazole core-shell nanoparticles (p-GAMCS NPs) film modified GC electrode. The p-GAMCS NPs film was fabricated on GC electrode by potentiodynamic method using 5-amino-2-mercapto-1,3,4-thiadiazole stabilized gold nanoparticles (AMT-AuNPs).

Optic disc dimensions and cup-disc ratios among healthy South Indians: The Chennai Glaucoma Study.

Purpose: To present optic disc and cup dimensions, cup-disc ratios (CDRs) and asymmetry among healthy South Indians, and their associations with ocular and systemic variables.

Methods: A total of 623 healthy phakic participants of the Chennai Glaucoma Study underwent complete eye examinations including optic disc stereo-photography. Planimetry was performed under stereo-viewing conditions.

Expression analysis of MAP2K9 and MAPK6 during pathogenesis of Alternaria blight in Arabidopsis thaliana ecotype Columbia.

Arabidopsis thaliana ecotype Columbia was used as a host in order to investigate the involvement of MAP kinase machinery in the pathogenesis of Alternaria blight. Semi-quantitative reverse transcriptase polymerase chain reaction and quantitative real time PCR based approaches were used to determine the change in transcript profile of MAP2K9 and MAPK6 in leaves of A. thaliana ecotpe Columbia at early, middle and late stages of Alternaria blight infection.

Collateral sensitivity of multidrug-resistant cells to the orphan drug tiopronin.

A major challenge in the treatment of cancer is multidrug resistance (MDR) that develops during chemotherapy. Here we demonstrate that tiopronin (1), a thiol-substituted N-propanoylglycine derivative, was selectively toxic to a series of cell lines expressing the drug efflux pump P-glycoprotein (P-gp, ABCB1) and MRP1 (ABCC1). Treatment of MDR cells with 1 led to instability of the ABCB1 mRNA and consequently a reduction in P-gp protein, despite functional assays demonstrating that tiopronin does not interact with P-gp.

Highly stable and sensitive glucose biosensor based on covalently assembled high density Au nanostructures.

We describe the development of a highly stable and sensitive glucose biosensor based on the nanohybrid materials derived from gold nanoparticles (AuNPs) and multi-walled carbon nanotubes (MWCNT). The biosensing platform was developed by using layer-by-layer (LBL) self-assembly of the nanohybrid materials and the enzyme glucose oxidase (GOx). A high density of AuNPs and MWCNT nanocomposite materials were constructed by alternate self assembly of thiol functionalized MWCNTs and AuNPs, followed by chemisoption of GOx.

Synthesis, characterization and electrocatalytic activity of fused gold nanoparticles.

This paper describes the synthesis of fused spherical gold nanoparticles (AuNPs) and their electrocatalytic activity towards the oxidation of hydroxylamine (HA). Fused AuNPs were prepared by one-pot synthesis using 2-mercapto-4-methyl-5-thiazoleacetic acid (TAA) as a stabilizing agent and sodium borohydride (NaBH4) as a reducing agent. The HR-TEM images showed that two individual AuNP were joined via on its surface with a size range of approximately 7 nm and a length of approximately 15 nm diameter.

The "specific" P-glycoprotein inhibitor Tariquidar is also a substrate and an inhibitor for breast cancer resistance protein (BCRP/ABCG2).

Tariquidar was developed as a specific inhibitor of the efflux transporter ABCB1. Recent positron emission tomographic brain imaging studies using [(11)C]tariquidar to measure ABCB1 (P-gp, P-glycoprotein) density in mice indicate that the inhibitor may not be as specific as previously thought. We examined its selectivity as an inhibitor and a substrate for the human transporters P-gp, breast cancer resistance protein (BCRP, ABCG2), and multidrug resistance protein 1 (MRP1, ABCC1).

Lysosomal trapping of a radiolabeled substrate of P-glycoprotein as a mechanism for signal amplification in PET.

The radiotracer [(11)C]N-desmethyl-loperamide (dLop) images the in vivo function of P-glycoprotein (P-gp), a transporter that blocks the entry of drugs that are substrates into brain. When P-gp is inhibited, [(11)C]dLop, a potent opiate agonist, enters and becomes trapped in the brain. This trapping is beneficial from an imaging perspective, because it amplifies the PET signal, essentially by accumulating radioactivity over time.

Evaluation of phototherapy devices used for neonatal hyperbilirubinemia.

Objective: To compare phototherapy devices based on their physical and photo-biological characteristics viz spectral properties, maximum and mean irradiance, treatable percentage of body surface area, decay of irradiance over time and in vitro photoisomerisation of bilirubin.

Design: In vitro experimental study.

Setting: Ocular pharmacy laboratory at a tertiary care hospital.

Bacteriophage-based rapid and sensitive detection of Escherichia coli O157:H7 isolates from ground beef.

We investigated the efficacy of bacteriophage-based detection technology to detect Escherichia coli O157:H7 from ground beef. The assay involved a short enrichment period of 8 h followed by capture of the pathogen on O157-specific immunomagnetic beads. The captured cells were treated with O157-specific lytic bacteriophage, CSLO157.

Effects of ketoconazole on the biodistribution and metabolism of [11C]loperamide and [11C]N-desmethyl-loperamide in wild-type and P-gp knockout mice.

Introduction: [(11)C]Loperamide and [(11)C]N-desmethyl-loperamide ([(11)C]dLop) have been proposed as radiotracers for imaging brain P-glycoprotein (P-gp) function. A major route of [(11)C]loperamide metabolism is N-demethylation to [(11)C]dLop. We aimed to test whether inhibition of CYP3A4 with ketoconazole might reduce the metabolism of [(11)C]loperamide and [(11)C]dLop in mice, and thereby improve the quality of these radiotracers.

N-desmethyl-loperamide is selective for P-glycoprotein among three ATP-binding cassette transporters at the blood-brain barrier.

[(11)C]N-desmethyl-Loperamide ([(11)C]dLop) is used in positron emission tomography (PET) to measure the in vivo activity of efflux transporters that block the passage of drugs across the blood-brain barrier. The three most prevalent ATP-binding cassette efflux transporters at the blood-brain barrier are P-glycoprotein (P-gp), multidrug resistance protein 1 (Mrp1), and breast cancer resistance protein (BCRP). We sought to measure the selectivity of dLop among these three transporters.

Highly sensitive determination of hydroxylamine using fused gold nanoparticles immobilized on sol-gel film modified gold electrode.

We are reporting the highly sensitive determination of hydroxylamine (HA) using 2-mercapto-4-methyl-5-thiazoleacetic acid (TAA) capped fused spherical gold nanoparticles (AuNPs) modified Au electrode. The fused TAA-AuNPs were immobilized on (3-mercaptopropyl)-trimethoxysilane (MPTS) sol-gel film, which was pre-assembled on Au electrode. The immobilization of fused TAA-AuNPs on MPTS sol-gel film was confirmed by UV-vis absorption spectroscopy and atomic force microscopy (AFM).

Osmoregulated periplasmic glucans synthesis gene family of Shigella flexneri.

Unlabelled: Osmoregulated periplasmic glucans (OPGs) of food- and water-borne enteropathogen Shigella flexneri were characterized. OPGs were composed of 100% glucose with 2-linked glucose as the most abundant residue with terminal glucose, 2-linked and 2,6-linked glucose also present in high quantities. Most dominant backbone polymer chain length was seven glucose residues.

Comparison of [(11)C]-(R)-PK 11195 and [(11)C]PBR28, two radioligands for translocator protein (18 kDa) in human and monkey: Implications for positron emission tomographic imaging of this inflammation biomarker.

Unlabelled: Ten percent of humans lack specific binding of [(11)C]PBR28 to 18 kDa translocator protein (TSPO), a biomarker for inflammation. "Non-binders" have not been reported using another TSPO radioligand, [(11)C]-(R)-PK 11195, despite its use for more than two decades. This study asked two questions: (1) What is the cause of non-binding to PBR28? and (2) Why has this phenomenon not been reported using [(11)C]-(R)-PK 11195?

Methods: Five binders and five non-binders received whole-body imaging with both [(11)C]-(R)-PK 11195 and [(11)C]PBR28.

Motility revertants of opgGH mutants of Salmonella enterica serovar Typhimurium remain defective in mice virulence.

We recently demonstrated that osmoregulated periplasmic glucans (OPGs) of Salmonella enterica serovar Typhimurium are required for optimal mouse virulence. However, lack of OPGs also generated pleiotropic phenotypes such as reduced motility and slower growth rate under hypoosmotic growth conditions. Whether the observed suboptimal virulence of opg mutants was due to reduced motility was investigated by isolating fully motile revertants of opgGH mutants.

Anti-diarrhoeal and ulcer-protective effects of violacein isolated from Chromobacterium violaceum in Wistar rats.

Violacein was isolated from Chromobacterium violaceum, a soil Gram-negative bacterium collected from the forest water body soil sample from Kolli Hills of Tamil Nadu, India. In the present study the anti-diarrhoeal and ulcer-protective properties of violacein were investigated in Wistar rats using castor oil, magnesium sulphate and ethanol. The intestinal transit in rats was significantly (P < 0.

Imaging the function of P-glycoprotein with radiotracers: pharmacokinetics and in vivo applications.

P-glycoprotein (P-gp), an efflux transporter, controls the pharmacokinetics of various compounds under physiological conditions. P-gp-mediated drug efflux has been suggested as playing a role in various disorders, including multidrug-resistant cancer and medication-refractory epilepsy. However, P-gp inhibition has had, to date, little or no clinically significant effect in multidrug-resistant cancer.

Osmoregulated periplasmic glucans of Salmonella enterica serovar Typhimurium are required for optimal virulence in mice.

We purified osmoregulated periplasmic glucans (OPGs) from Salmonella enterica serovar Typhimurium and found them to be composed of 100 % glucose with 2-linked glucose as the most abundant residue, with terminal glucose, 2,3-linked and 2,6-linked glucose also present in high quantities. The two structural genes for OPG biosynthesis, opgG and opgH, form a bicistronic operon, and insertion of a kanamycin resistance gene cassette into this operon resulted in a strain devoid of OPGs. The opgGH mutant strain was impaired in motility and growth under low osmolarity conditions.

Cyclo-hexane-1,2,3,4,5-pentol.

In the title compound, C(6)H(12)O(5), the cyclo-hexane ring adopts a chair conformation. The absolute configuration is not defined. However, the relative configuration can be assigned as 1R*,3R*,4S*,S*.

Piperazinediium dioxamate.

The title compound, C(4)H(12)N(2) (2+)·2C(2)H(2)NO(3) (-), contains a network of doubly protanated piperazinium cations (lying about centres of inversion) and dioxamate anions. The piperazinium dication adopts a typical chair conformation. The crystal structure is stabilized by cation-to-anion N-H⋯O and anion-to-anion N-H⋯O hydrogen bonds.

Amino-guanidinium hydrogen succinate.

The title compound, CH(7)N(4) (+)·C(4)H(5)O(4) (-), is a molecular salt containing discrete amino-guanidinium and succinate ions. The amino-guanidinium cation is nearly planar, with a maximum deviation of 0.035 (1) Å.

Determination of nanomolar uric and ascorbic acids using enlarged gold nanoparticles modified electrode.

Individual and simultaneous determination of 50nM uric acid (UA) and ascorbic acid (AA) using enlarged, citrate-stabilized gold nanoparticles (AuNPs) self-assembled to 2,5-dimercapto-1,3,4-thiadiazole (DMT) monolayer modified Au (Au/DMT) electrode by an amperometric method is described for the first time. Self-assembly of AuNPs on the electrode surface was confirmed by atomic force microscopy (AFM), attenuated total reflectance FT-IR and diffuse reflectance spectral measurements. The electron transfer reaction (ETR) of [Fe(CN)(6)](3-/4-) was blocked at Au/DMT electrode, whereas it was restored with a peak separation of 200mV after the attachment of AuNPs on the Au/DMT (Au/DMT/AuNPs) electrode, which was confirmed from the ETR of the [Fe(CN)(6)](3-/4-) redox couple.

Radiodefluorination of 3-fluoro-5-(2-(2-[18F](fluoromethyl)-thiazol-4-yl)ethynyl)benzonitrile ([18F]SP203), a radioligand for imaging brain metabotropic glutamate subtype-5 receptors with positron emission tomography, occurs by glutathionylation in rat brain.

Metabotropic glutamate subtype-5 receptors (mGluR5) are implicated in several neuropsychiatric disorders. Positron emission tomography (PET) with a suitable radioligand may enable monitoring of regional brain mGluR5 density before and during treatments. We have developed a new radioligand, 3-fluoro-5-(2-(2-[(18)F](fluoromethyl)thiazol-4-yl)ethynyl)benzonitrile ([(18)F]SP203), for imaging brain mGluR5 in monkey and human.

Kinetic brain analysis and whole-body imaging in monkey of [11C]MNPA: a dopamine agonist radioligand.

With a view to future extension of the use of the agonist radioligand [(11)C]MNPA ([O-methyl-(11)C]2-methoxy-N-propylnorapomorphine) from animals to humans, we performed two positron emission tomography (PET) studies in monkeys. First, we assessed the ability to quantify the brain uptake of [(11)C]MNPA with compartmental modeling. Second, we estimated the radiation exposure of [(11)C]MNPA to human subjects based on whole-body imaging in monkeys.