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1.
Expert Rev Cardiovasc Ther ; 21(5): 357-364, 2023 May.
Article in English | MEDLINE | ID: mdl-37024997

ABSTRACT

OBJECTIVES: Cardiac rehabilitation - programs comprehensively delivering outpatient secondary prevention - is under-available and under-studied in the resource-poor settings where it is needed most. This report summarizes the governance, participating sites, patient characteristics and outcomes, as well as knowledge translation activities during first year of operation of ICCPR's registry, namely the International Cardiac Rehab Registry. METHODS: A pilot study was undertaken with five centers, demonstrating feasibility, satisfaction with the on-boarding processes, as well as data quality. RESULTS: Fourteen centers have been engaged from all regions but Europe; Data have been entered on >1000 patients (18.1% female; mean age = 57.6), of whom 62.4% completed their programs and 19.9% dropped out for work or clinical reasons. Post-program, completers had significantly better work status, functional capacity, medication adherence, physical activity levels, diet, as well as lower tobacco use than non-completers (all p < 0.05). A site Certification program was developed and piloted, with five centers now recognized for their quality, given they met over 70% of the 13 internationally agreed standards based on Registry data and a virtual site assessment. CONCLUSION: Annual assessments have started. Quality improvement activities will soon be underway. We continue to invite new programs, supporting development in resource-poor settings to the benefit of patients served.


Subject(s)
Cardiac Rehabilitation , Cardiovascular Diseases , Humans , Female , Middle Aged , Male , Pilot Projects , Europe , Cardiovascular Diseases/prevention & control , Registries
2.
Phys Rev Lett ; 128(3): 033202, 2022 Jan 21.
Article in English | MEDLINE | ID: mdl-35119894

ABSTRACT

We report the first operation of a Ra^{+} optical clock, a promising high-performance clock candidate. The clock uses a single trapped ^{226}Ra^{+} ion and operates on the 7s ^{2}S_{1/2}→6d ^{2}D_{5/2} electric quadrupole transition. By self-referencing three pairs of symmetric Zeeman transitions, we demonstrate a frequency instability of 1.1×10^{-13}/sqrt[τ], where τ is the averaging time in seconds. The total systematic uncertainty is evaluated to be Δν/ν=9×10^{-16}. Using the clock, we realize the first measurement of the ratio of the D_{5/2} state to the S_{1/2} state Landé g-factors: g_{D}/g_{S}=0.598 805 3(11). A Ra^{+} optical clock could improve limits on the time variation of the fine structure constant, α[over ˙]/α, in an optical frequency comparison. The ion also has several features that make it a suitable system for a transportable optical clock.

3.
Indian Heart J ; 70 Suppl 3: S480-S482, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30595311

ABSTRACT

Genome wide association study has identified rs7025486 G>A polymorphism within DAB2IP (Disabled homolog 2-interacting protein) gene with increased risk of coronary heart disease (CAD). In this study we have determined the frequency and association of rs7025486 with CAD in Indians. The study was performed on 214 patients with CAD and 125 controls. The 'AA' genotype was associated with an increased risk in the CAD age group <50 yrs as compared to CAD age group>50 yrs (OR 3.149; P 0.034) and controls >50 yrs (OR 3.430; P 0.080). The risk allele (A) was significantly associated with premature CAD.


Subject(s)
Coronary Artery Disease/genetics , Genetic Predisposition to Disease , Polymorphism, Single Nucleotide , ras GTPase-Activating Proteins/genetics , Alleles , Coronary Artery Disease/epidemiology , Coronary Artery Disease/metabolism , DNA/genetics , Female , Genome-Wide Association Study , Genotype , Humans , Incidence , India/epidemiology , Male , Middle Aged , Risk Factors , ras GTPase-Activating Proteins/metabolism
4.
Heart ; 102(18): 1449-1455, Septemberr 15, 2016.
Article in English | BIGG - GRADE guidelines | ID: biblio-966102

ABSTRACT

"OBJECTIVE: Cardiovascular disease is a global epidemic, which is largely preventable. Cardiac rehabilitation (CR) is demonstrated to be cost-effective and efficacious in high-income countries. CR could represent an important approach to mitigate the epidemic of cardiovascular disease in lower-resource settings. The purpose of this consensus statement was to review low-cost approaches to delivering the core components of CR, to propose a testable model of CR which could feasibly be delivered in middle-income countries. METHODS: A literature review regarding delivery of each core CR component, namely: (1) lifestyle risk factor management (ie, physical activity, diet, tobacco and mental health), (2) medical risk factor management (eg, lipid control, blood pressure control), (3) education for self-management and (4) return to work, in low-resource settings was undertaken. Recommendations were developed based on identified articles, using a modified GRADE approach where evidence in a low-resource setting was available, or consensus where evidence was not. RESULTS: Available data on cost of CR delivery in low-resource settings suggests it is not feasible to deliver CR in low-resource settings as is delivered in high-resource ones. Strategies which can be implemented to deliver all of the core CR components in low-resource settings were summarised in practice recommendations, and approaches to patient assessment proffered. It is suggested that CR be adapted by delivery by non-physician healthcare workers, in non-clinical settings. CONCLUSIONS: Advocacy to achieve political commitment for broad delivery of adapted CR services in low-resource settings is needed."


Subject(s)
Humans , Cardiovascular Diseases , Cardiovascular Diseases/diagnosis , Cardiovascular Diseases/therapy , Self Care , Activities of Daily Living , Patient Education as Topic , Health Care Costs , Cost-Benefit Analysis , Models, Organizational , Delivery of Health Care , Risk Reduction Behavior , Consensus , Exercise Therapy , Return to Work , Health Resources
5.
Chaos ; 25(6): 064609, 2015 Jun.
Article in English | MEDLINE | ID: mdl-26117134

ABSTRACT

We have studied, experimentally, the collective behavior of the electrically coupled autonomous Mercury Beating Heart (MBH) systems exhibiting the breathing mode, by varying both the coupling strength and the population size (from N = 3 to N = 16). For a fixed N, the electrical and the mechanical activities of the MBH systems achieve complete synchronization at different coupling strengths. The electrical activity of each MBH system is measured by the corresponding electrode potential (Ei = Vi). Additionally, the mechanical activity of each MBH oscillator is visually observed (snapshots and video clips). Subsequently, this activity is quantified by calculating the temporal variation in the area (Ai) of the Hg drop. As a result, the synchronization of the electrical (Ei = Vi) and the mechanical (Ai) activities can be measured. The extent of synchronization was quantified by employing the order parameter (r). Our experimental results are found to be in agreement with the Kuramoto theory.

6.
J Phys Chem A ; 118(26): 4647-51, 2014 Jul 03.
Article in English | MEDLINE | ID: mdl-24896219

ABSTRACT

The ability of the mercury beating heart (MBH) system to exhibit sustained mechanical and electrochemical activities simultaneously without any external agent (fluctuating or constant), has attracted researchers for decades. The interplay of these activities could mimic the biological phenomena such as a pulsating heart that occurs due to the coupled tissues exhibiting mechanical as well as electrical dynamics. In the present work, we have studied experimentally the dynamics of electrically coupled two and three autonomous MBH systems. A dynamical triangular (heart) shape, in the traditional watch glass geometry, has been chosen for the experiments. It is found that the redox potentials (electrical behavior) of the quasi-identical (due to the inherent heterogeneities in the setup) MBH systems get synchronized at the intermediate coupling strengths whereas coherence in their mechanical activities occur only at large coupling strengths. To the best of our knowledge, this synchronization phenomenon involving two distinct activities (electrical and mechanical) and different coupling thresholds has not been reported, so far. The coherent mechanical activities means the simultaneous occurrence of compressions and expansions in the coupled Hg drops, which are shown using snapshots. In addition to this, the redox time series have also been provided to demonstrate the synchronization in the electrical behavior of MBH systems. Moreover, a mathematical framework considering only electrical and mechanical components of the MBH systems is presented to validate the experimental findings that the strong synchrony in the redox potentials of the MBH systems is a prerequisite for the synchrony in their mechanical activities.


Subject(s)
Electromagnetic Phenomena , Heart/physiology , Iron/chemistry , Mechanics , Mercury/chemistry , Platinum/chemistry , Computer Simulation , Mathematics , Oscillometry , Oxidation-Reduction
7.
J Phys Chem A ; 117(2): 267-74, 2013 Jan 17.
Article in English | MEDLINE | ID: mdl-23276204

ABSTRACT

We study the dynamics of the mercury beating heart (MBH) system in an acidic solution in the absence of a strong oxidant. Furthermore, the system is subjected to an external square wave potential. It was observed that different shapes (circular, elliptical, triangular, and multilobed stars) of the mercury drop could be stabilized as the frequency of the external potential and the volume of the mercury were varied. The redox potential time series for this forced MBH system, corresponding to the different stabilized topological configurations, were also recorded, and their power spectra were analyzed. The obtained results, involving the different topological modes, were fairly reproducible and sustainable. A possible oxidation-reduction mechanism for these experimental observations is provided.

8.
Neurology ; 77(18): 1698-701, 2011 Nov 01.
Article in English | MEDLINE | ID: mdl-22013185

ABSTRACT

OBJECTIVE: To report the metabotropic glutamate receptor 5 (mGluR5) as the autoantigen of antibodies from 2 patients with Hodgkin lymphoma (HL) and limbic encephalopathy (Ophelia syndrome). METHODS: Immunohistochemistry with brain tissue and cultures of rat hippocampal neurons were used to demonstrate antibodies. Immunoprecipitation, mass spectrometry, and mGluR5-null mice served to identify the antigen. HEK293 cells transfected with mGluR5 or mGluR1 were used to determine immunologic crossreactivity. RESULTS: Both patients developed symptoms consistent with limbic encephalopathy; one had MRI findings typical of this disorder and the other had more extensive radiologic involvement, including parietal and occipital cortex. Patients' sera had antibodies that predominantly reacted with the neuropil of hippocampus and cell surface of live hippocampal neurons. Immunoprecipitation from cultured neurons and mass spectrometry demonstrated that the antigen was mGluR5, a receptor involved in processes of learning and memory. The reactivity of patients' sera was abrogated in brain of mGluR5-null mice, further confirming the antibody specificity. Studies with a large number of controls including 2 patients with cerebellar ataxia and mGluR1 antibodies showed that mGluR5 was only identified by sera of the 2 patients with the Ophelia syndrome, and that despite the homology of this receptor with mGluR1 each autoantigen was specific for a distinct syndrome. CONCLUSIONS: Antibodies to mGluR5 should be considered in patients with symptoms of limbic encephalitis and HL (Ophelia syndrome). Recognition of this disorder is important because it can affect young individuals and is reversible.


Subject(s)
Autoantibodies/immunology , Autoantigens/immunology , Receptors, Metabotropic Glutamate/immunology , Adolescent , Animals , Cells, Cultured , Female , HEK293 Cells , Hippocampus/cytology , Hodgkin Disease/immunology , Hodgkin Disease/pathology , Humans , Limbic Encephalitis/immunology , Limbic Encephalitis/pathology , Male , Middle Aged , Neurons/cytology , Neurons/metabolism , Rats , Receptor, Metabotropic Glutamate 5 , Receptors, Metabotropic Glutamate/genetics , Syndrome
9.
Mol Psychiatry ; 16(10): 1048-61, 2011 Oct.
Article in English | MEDLINE | ID: mdl-20603624

ABSTRACT

High-affinity nicotinic receptors containing ß2 subunits (ß2*) are widely expressed in the brain, modulating many neuronal processes and contributing to neuropathologies such as Alzheimer's disease, Parkinson's disease and epilepsy. Mutations in both the α4 and ß2 subunits are associated with a rare partial epilepsy, autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE). In this study, we introduced one such human missense mutation into the mouse genome to generate a knock-in strain carrying a valine-to-leucine mutation ß2V287L. ß2(V287L) mice were viable and born at an expected Mendelian ratio. Surprisingly, mice did not show an overt seizure phenotype; however, homozygous mice did show significant alterations in their activity-rest patterns. This was manifest as an increase in activity during the light cycle suggestive of disturbances in the normal sleep patterns of mice; a parallel phenotype to that found in human ADNFLE patients. Consistent with the role of nicotinic receptors in reward pathways, we found that ß2(V287L) mice did not develop a normal proclivity to voluntary wheel running, a model for natural reward. Anxiety-related behaviors were also affected by the V287L mutation. Mutant mice spent more time in the open arms on the elevated plus maze suggesting that they had reduced levels of anxiety. Together, these findings emphasize several important roles of ß2* nicotinic receptors in complex biological processes including the activity-rest cycle, natural reward and anxiety.


Subject(s)
Circadian Rhythm/genetics , Epilepsy, Frontal Lobe/physiopathology , Motor Activity/genetics , Receptors, Nicotinic/metabolism , Sleep/genetics , Animals , Chimera , Circadian Rhythm/physiology , Disease Models, Animal , Epilepsy, Frontal Lobe/genetics , Epilepsy, Frontal Lobe/metabolism , Exploratory Behavior/physiology , Gene Knock-In Techniques , Humans , Mice , Mice, Inbred C57BL , Mice, Neurologic Mutants , Receptors, Nicotinic/genetics , Sleep/physiology , Wakefulness/genetics , Wakefulness/physiology
11.
Anal Chem ; 75(21): 5673-9, 2003 Nov 01.
Article in English | MEDLINE | ID: mdl-14588004

ABSTRACT

Microtubule sensors for glucose, urea, and triglyceride were fabricated based on poly(styrene sulfonate)-polyaniline (PSS-PANI) composites synthesized within the pores of track-etched polycarbonate membranes. The synthesis of a sufficiently thick and conducting PSS-PANI film at pH 5 provided the advantage of immobilizing enzymes during polymerization. This resulted in the improvement of sensor response for urea and triglyceride by a factor of approximately 10(2) with a significant increase in the linear region of response compared to polyaniline-based sensors, where the enzymes were immobilized by physical adsorption after the polymerization. The sensors based on urea and triglyceride were found to have a higher linear range of response, better sensitivity, improved multiple use capability, and faster response time compared to the potentiometric and amperometric sensors based on polyaniline. A microtubule sensor array for glucose, urea, and triglyceride based on PSS-PANI was fabricated by immobilization of three different sets of enzymes on three closely spaced devices and its response was found to be free from cross-interference when a sample containing a mixture of the above analytes was analyzed in a single measurement.

12.
Chem Commun (Camb) ; (7): 680-1, 2002 Apr 07.
Article in English | MEDLINE | ID: mdl-12119672

ABSTRACT

A conductimetric reagentless immunosensor using the biospecific binding pair of goat antirabbit IgG and rabbit IgG has been designed and fabricated using poly (3,4-ethylenedioxythiophene) as the immobilization matrix-cumtransducer.


Subject(s)
Antigens/analysis , Biosensing Techniques/methods , Immunoglobulin G/analysis , Animals , Antibodies, Anti-Idiotypic , Bridged Bicyclo Compounds, Heterocyclic/chemistry , Electric Conductivity , Electrochemistry , Goats , Immunoassay/instrumentation , Immunoglobulin G/immunology , Polymers/chemistry , Rabbits
13.
Chem Commun (Camb) ; (3): 240-1, 2002 Feb 07.
Article in English | MEDLINE | ID: mdl-12120384

ABSTRACT

Electrochemical homopolymerization of metanillic acid has been achieved for the first time using a 4:1 acetonitrile-water mixture to get 100% sulfonated polyaniline which is soluble in both organic and aqueous solvents, electrically conducting, and is n-dopable.

14.
J Pharmacol Exp Ther ; 296(2): 650-8, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11160654

ABSTRACT

Dysiherbaine (DH) is a marine sponge-derived amino acid that causes seizures upon injection into mice. In this report we investigate the behavioral effects and characterize the pharmacological activity of DH. DH induced convulsive behaviors in mice with ED(50) values of 13 pmol/mouse, i.c.v. and 0.97 mg/kg, i.p. In rat brain synaptic membranes DH displaced binding of [3H]kainic acid (KA) and [3H]alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) with K(i) values of 26 and 153 nM, respectively; in contrast, DH did not displace the N-methyl-D-aspartic acid (NMDA) receptor ligand [3H]CGS-19755. DH displaced [3H]KA from recombinant GluR5 and GluR6 kainate receptor subunits expressed in HEK293 cells with K(i) values of 0.74 and 1.2 nM, respectively. In whole-cell voltage-clamp recordings from cultured rat hippocampal neurons, DH evoked inward currents from both AMPA and KA receptors with EC(50) values of 9.7 microM and 210 nM, respectively. AMPA receptor currents were blocked by GYKI 53655, whereas KA receptor currents were blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). Surprisingly, in calcium imaging experiments we found that DH also activated recombinant mGluR5 receptors but did not activate mGluR1 receptors. DH did not activate glutamate transporters or gamma-aminobutyric acid A (GABA(A)) receptors. These results indicate that DH is a potent non-NMDA-type agonist with very high affinity for KA receptors, as well as a subtype-selective mGluR agonist. DH possesses the most potent epileptogenic activity among the amino acids yet identified. This novel excitatory amino acid may prove useful for evaluating the physiological and pathological roles of non-NMDA receptors, especially KA receptors, in the central nervous system.


Subject(s)
Alanine/pharmacology , Bridged Bicyclo Compounds, Heterocyclic/pharmacology , Convulsants/pharmacology , Excitatory Amino Acid Agonists/pharmacology , Porifera/chemistry , ATP-Binding Cassette Transporters/metabolism , Alanine/analogs & derivatives , Alanine/pharmacokinetics , Amino Acid Transport System X-AG , Animals , Bridged Bicyclo Compounds, Heterocyclic/pharmacokinetics , Calcium/metabolism , Cells, Cultured , Convulsants/pharmacokinetics , Diagnostic Imaging , Excitatory Amino Acid Agonists/pharmacokinetics , In Vitro Techniques , Injections, Intraventricular , Male , Mice , Neurons/metabolism , Radioligand Assay , Rats , Rats, Sprague-Dawley , Receptors, Metabotropic Glutamate/agonists , Seizures/chemically induced , Seizures/psychology , Synaptic Membranes/metabolism
15.
Neuron ; 29(1): 209-16, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11182092

ABSTRACT

Kainate receptors alter the excitability of mossy fiber axons and have been reported to play a role in the induction of long-term potentiation (LTP) at mossy fiber synapses in the hippocampus. These previous studies have relied primarily on the use of compounds whose selectivity is unclear. In this report, we investigate short- and long-term facilitation of mossy fiber synaptic transmission in kainate receptor knockout mice. We find that LTP is reduced in mice lacking the GluR6, but not the GluR5, kainate receptor subunit. Additionally, short-term synaptic facilitation is impaired in GluR6 knockout mice, suggesting that kainate receptors act as presynaptic autoreceptors on mossy fiber terminals to facilitate synaptic transmission. These data demonstrate that kainate receptors containing the GluR6 subunit are important modulators of mossy fiber synaptic strength.


Subject(s)
Long-Term Potentiation/physiology , Mossy Fibers, Hippocampal/metabolism , Neuronal Plasticity/physiology , Receptors, Kainic Acid/metabolism , Synapses/metabolism , Animals , Cyclic AMP-Dependent Protein Kinases/metabolism , Electric Stimulation/methods , Excitatory Postsynaptic Potentials/physiology , In Vitro Techniques , Long-Term Potentiation/genetics , Mice , Mice, Knockout , Neuronal Plasticity/genetics , Receptors, Kainic Acid/deficiency , Receptors, Kainic Acid/genetics , Receptors, Metabotropic Glutamate/metabolism , Synapses/genetics , Synaptic Transmission/physiology , GluK2 Kainate Receptor
16.
J Neurosci ; 21(4): 1228-37, 2001 Feb 15.
Article in English | MEDLINE | ID: mdl-11160393

ABSTRACT

Functional NMDA receptors are heteromultimeric complexes of the NR1 subunit in combination with at least one of the four NR2 subunits (A-D). Coexpression of NR3A, an additional subunit of the NMDA receptor family, modifies NMDA-mediated responses. It is unclear whether NR3A interacts directly with NR1 and/or NR2 subunits and how such association might regulate the intracellular trafficking and membrane expression of NR3A. Here we show that NR3A coassembles with NR1-1a and NR2A to form a receptor complex with distinct single-channel properties and a reduced relative calcium permeability. NR3A associates independently with both NR1-1a and NR2A in the endoplasmic reticulum, but only heteromeric complexes containing the NR1-1a NMDA receptor subunit are targeted to the plasma membrane. Homomeric NR3A complexes or complexes composed of NR2A and NR3A were not detected on the cell surface and are retained in the endoplasmic reticulum. Coexpression of NR1-1a facilitates the surface expression of NR3A-containing receptors, reduces the accumulation of NR3A subunits in the endoplasmic reticulum, and induces the appearance of intracellular clusters where both subunits are colocalized. Our data demonstrate a role for subunit oligomerization and specifically assembly with the NR1 subunit in the trafficking and plasma membrane targeting of the receptor complex.


Subject(s)
Kidney/metabolism , Protein Subunits , Receptors, N-Methyl-D-Aspartate/metabolism , Animals , Calcium/metabolism , Cell Line , Cell Membrane/metabolism , Endoplasmic Reticulum/metabolism , Fluorescent Antibody Technique , Gene Expression , Humans , Intracellular Fluid/metabolism , Kidney/cytology , Patch-Clamp Techniques , Permeability , Precipitin Tests , Rats , Receptors, N-Methyl-D-Aspartate/genetics , Transfection
17.
J Neurosci ; 20(22): 8269-78, 2000 Nov 15.
Article in English | MEDLINE | ID: mdl-11069933

ABSTRACT

To understand the physiological role of kainate receptors and their participation in seizure induction in animal models of epilepsy, it will be necessary to develop a comprehensive description of their action in the CA3 region of the hippocampus. Activation of presynaptic kainate receptors depresses excitatory synaptic transmission at mossy fiber and associational-commissural inputs to CA3 pyramidal neurons (Vignes et al., 1998; Bortolotto et al., 1999; Kamiya and Ozawa, 2000). In this study, we use gene-targeted mice lacking glutamate receptor 5 (GluR5) or GluR6 kainate receptor subunits to identify the receptor subunits that comprise the kainate receptors responsible for presynaptic modulation of CA3 transmission. We found that bath application of kainate (3 microm) profoundly reduced EPSCs at mossy fiber and collateral synapses in neurons from wild-type and GluR5(-/-) mice but had no effect on EPSCs in neurons from GluR6(-/-) mice. These results therefore contrast with previous studies that supported a role for GluR5-containing receptors at mossy fiber and associational-commissural synapses (Vignes et al., 1998; Bortolotto et al., 1999). Surprisingly, at perforant path synapses kainate receptor activation enhanced transmission; this potentiation was abolished in both GluR5 and GluR6 knock-out mice. Kainate receptors thus play multiple and complex roles to modulate excitatory synaptic transmission in the CA3 region of the hippocampus.


Subject(s)
Hippocampus/metabolism , Receptors, Kainic Acid/physiology , Synaptic Transmission/physiology , Animals , Excitatory Amino Acid Agonists/pharmacology , Excitatory Amino Acid Antagonists/pharmacology , Excitatory Postsynaptic Potentials/drug effects , GABA Antagonists/pharmacology , GABA-A Receptor Antagonists , Hippocampus/cytology , Hippocampus/drug effects , In Vitro Techniques , Kainic Acid/metabolism , Kainic Acid/pharmacology , Mice , Mice, Inbred Strains , Mice, Knockout , Mossy Fibers, Hippocampal/drug effects , Mossy Fibers, Hippocampal/metabolism , Neural Inhibition/drug effects , Neural Inhibition/physiology , Neurons/cytology , Neurons/drug effects , Neurons/metabolism , Patch-Clamp Techniques , Perforant Pathway/cytology , Perforant Pathway/drug effects , Perforant Pathway/metabolism , Receptors, Kainic Acid/deficiency , Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors , Receptors, Presynaptic/metabolism , Synapses/drug effects , Synapses/metabolism , Synaptic Transmission/drug effects , GluK2 Kainate Receptor
18.
Anal Chem ; 71(11): 2231-6, 1999 Jun 01.
Article in English | MEDLINE | ID: mdl-21662760

ABSTRACT

This paper describes the fabrication of microtubular biosensors and sensor arrays based on polyaniline with superior transducing ability. These sensors have been tested for the estimation of glucose, urea, and triglycerides. As compared to that of a macro sensor, the response of the microtubular sensor for glucose is higher by a factor of more than 10(3). Isoporous polycarbonate membranes have been used to fabricate inexpensive devices by simple thermal evaporation of gold using appropriate machined masks. Polyaniline deposition and enzyme immobilization have been done electrochemically. Electrochemical potential control has been used to direct enzyme immobilization to the chosen membrane device and avoid cross talk with adjacent devices. This has enabled the immobilization of a set of three different enzymes on three closely spaced devices, resulting in a microtubule array that can analyze a sample containing a mixture of glucose, urea, and triglycerides in a single measurement. This, in essence, is an "electronic tongue".

19.
Proc Natl Acad Sci U S A ; 95(15): 8969-74, 1998 Jul 21.
Article in English | MEDLINE | ID: mdl-9671788

ABSTRACT

The actions of glutamate in the central nervous system are mediated through interaction with fast activating ionotropic receptors and G protein-coupled metabotropic glutamate receptors (mGluRs). Studies of these receptors have relied on the availability of agonists and antagonists selective for each receptor class. Compounds that were thought to be selective for mGluRs have been extensively used to study the role of these receptors in the brain. Their use has implicated mGluRs in a wide range of physiological and pathological processes including the modulation of N-methyl-D-aspartate (NMDA) receptors and NMDA receptor-dependent processes. We report that some of the most commonly used mGluR compounds act as antagonists on NMDA receptors at concentrations commonly used to activate or block mGluRs. In addition, several of the drugs also act as agonists at higher concentrations due at least in part to high levels of contaminant amino acids. Our results indicate that caution should be used when using these drugs to study the roles of mGluRs in various NMDA-dependent processes. The antagonist effects were dependent on the concentration of the NMDA receptor coagonists, preventing reappraisal of previously published work.


Subject(s)
Excitatory Amino Acid Agents/pharmacology , Receptors, Metabotropic Glutamate/drug effects , Receptors, N-Methyl-D-Aspartate/drug effects , Animals , Cell Line , Hippocampus/cytology , Hippocampus/drug effects , Hippocampus/metabolism , Humans , Neurons/drug effects , Neurons/metabolism , Receptors, N-Methyl-D-Aspartate/genetics , Recombinant Proteins/drug effects , Recombinant Proteins/genetics , Xenopus
20.
Eur J Biochem ; 258(2): 419-29, 1998 Dec 01.
Article in English | MEDLINE | ID: mdl-9874207

ABSTRACT

We have isolated cDNAs coding for the complete amino acid sequences of cholinesterase 1 (ChE1) and cholinesterase 2 (ChE2) from amphioxus. Both ChE transcripts have the characteristics of H-type catalytic subunits, which are inserted in the membrane via an ethanolamine-glycan-phosphatidylinositol anchor. The members of the catalytic triad of ChEs, the three pairs of cysteine residues involved in intrachain disulfide bonding, a cysteine near the carboxy terminal of both sequences, which could mediate interchain disulfide bonding, and 11 of the 14 aromatic amino acids that line the catalytic gorge of AChE are conserved. A remarkable difference between the two enzymes is in the region of the acyl-binding pocket, which plays an important role in determining substrate specificity in cholinesterases. ChE2 contains a sequence that resembles the acyl pocket of invertebrate ChE, while the acyl-binding site of ChE1 is novel. There are also differences between the two enzymes in the peripheral anionic site, which mediates inhibition by certain ligands. In vitro expression in COS-7 cells demonstrates that ChE2 hydrolyzes acetylthiocholine almost exclusively, while ChE1 hydrolyzes both acetylthiocholine and butyrylthiocholine. Both enzymes are inhibited comparably by BW284c51, but ChE1 is considerably more resistant to inhibition by propidium, ethopropazine, and eserine than is ChE2. Velocity sedimentation indicates that ChE1 and ChE2 are present as amphiphilic and nonamphiphilic G2 forms in vivo and in vitro. Another molecular form, which sediments at 17 S, is also present in vivo. Nondenaturing gel electrophoresis in conjunction with digestion by phosphatidylinositol-specific phospholipase C demonstrates that the vast majority of ChE1 and ChE2 is present as ethanolamine-glycan-phosphatidylinositol-anchored G2 forms in vivo. ChE1 also possesses an ethanolamine-glycan-phosphatidylinositol-anchor in vitro; however, ChE2 produced in vitro could not be detected on nondenaturing gels.


Subject(s)
Cholinesterases/genetics , Chordata, Nonvertebrate/enzymology , Acetylthiocholine/metabolism , Amino Acid Sequence , Animals , Binding Sites/genetics , Cholinesterases/chemistry , Cloning, Molecular , Electrophoresis, Polyacrylamide Gel , Enzyme Inhibitors/pharmacology , Gene Expression/genetics , Hydrogen-Ion Concentration , Kinetics , Molecular Sequence Data , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Ultracentrifugation
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