Application Of Digital Signal Analysis, Mass Data Acquisition and Processing Techniques, and Automated Experiment Protocols to the Study of Cardiac Cell Membrane Electrophysiology, with Mathematical Modeling

Traditional methods of collecting, analyzing and storing data from cardiac cell membrane electrophysiology experiments have become increasingly cumbersome and unwieldy as experimental protocols have become more sophisticated and complex. A global approach to collecting, analyzing, refining and storing electrophysiologic data, as well as a new approach to mathematical modeling of cell membrane single ion channel kinetics, was developed. This utilizes a comprehensive microcomputer based system of software with specialized analog and digital electronics for data acquisition, analysis and archiving. Unique discrete signal processing techniques for characterizing the electronic recording system, including specialized hardware and software adapted for minimizing distortions in biosignal recordings, are discussed in detail

Changing the Price of Marriage: Evidence from Blood Test Requirements

We use state repeals of blood test requirements for a marriage license that occurred between 1980 and 2005 to examine the impact of changes in the price of marriage on the marriage decision. Using a within-group estimator that holds constant state and year effects and exploits variation in the repeal dates of BTRs across states, we find that BTRs are associated with a 5.7% decrease in marriage licenses issued by a state. Using individual-level marriage license data from 1981-1995, we find that about half of this effect is due to couples seeking marriage licenses in other states, with the other half is due to deterred marriages. We also examine the marital status of mothers using birth certificate and Current Population Survey data, and find that blood test requirements reduce the fraction of first-time mothers who are married at the time of birth. The marriage-deterrent effects of BTRs are larger for lower socio-economic groups.

SSL: A software specification language

SSL (Software Specification Language) is a new formalism for the definition of specifications for software systems. The language provides a linear format for the representation of the information normally displayed in a two-dimensional module inter-dependency diagram. In comparing SSL to FORTRAN or ALGOL, it is found to be largely complementary to the algorithmic (procedural) languages. SSL is capable of representing explicitly module interconnections and global data flow, information which is deeply imbedded in the algorithmic languages. On the other hand, SSL is not designed to depict the control flow within modules. The SSL level of software design explicitly depicts intermodule data flow as a functional specification

Provenance of tetraether membrane lipids in a large temperate lake (Loch Lomond, UK): implications for glycerol dialkyl glycerol tetraether (GDGT)-based palaeothermometry

The application of glycerol dialkyl glycerol tetraether (GDGT)-based palaeoenvironmental proxies, such as the branched vs. isoprenoidal tetratether (BIT) index, TEX86 and the MBT–CBT palaeothermometer, has lately been expanded to lacustrine sediments. Given recent research identifying the production of branched, bacterial GDGTs (brGDGTs) within lakes, it is necessary to ascertain the effect of this lacustrine production on GDGT-based proxies. This study profiles a temperate, monomictic lake (Loch Lomond, UK), analysing labile intact polar GDGT lipids (IPLs) and resilient core GDGT lipids (CLs) in catchment soils, small tributary rivers, lake water and lake sediments

947-111 IkBlockade Selectively Eliminates Slow Antegrade Atrioventricular Nodal Conduction in the Rabbit

We studied the effects of an Ikblocker, risotilide (R) on the dynamic properties of perfused rabbit AV nodes using intermittent right atrial premature pacing and bipolar surface electrograms. R was serially perfused with 1, 3 and6× 10–6M R for 15 minutes following pre-drug measurements.ResultsTypical changes in the antegrade recovery curve produced by R are shown in the figure. There was a concentration dependent decrease in Δ.AH from the pre-drug value of 56±15 ms to 29.2±16.9 ms and 13.7±5.9 ms by 3 and6× 10-6M respectively (n = 6). A reciprocal increase in the AV node effective refractory period was observed from 91±15 ms (pre-drug) to 139±16 ms (3×10-6M) and 170±16 ms (6 × 10-6M). AH∝ was unchanged at any concentration of R.ConclusionsThese results suggest that class III antiarrhythmic agents may increase action potential duration and the refractory period of the structure(s) limiting AV conduction and thereby eliminate a majority of the “slow” AV node conduction. These findings may have important implications for a pharmacologic approach to the treatment of AV node reentry tachycardias

799-2 Left Ventricular (LV) and Myocyte Electrophysiology with the Development of Dilated Cardiomyopathy (DCM); Effects of Angiotensin II Receptor (AT1 AT-II) Blockade

Ventricular arrhythmias are a significant cause of morbidity and mortality with DCM, and AT1 AT-II receptor activation has been implicated to play a role in arrhythmogenesis. However, the effects of AT1, AT-II receptor activation on changes in LV function and myocyte electrophysiology during the progression of DCM remain unexplored. Accordingly, this study measured weekly changes in LV function (ejection fraction, LVEF; peak systolic wall stress, LVWS) and surface electrocardiography (R-R interval, QRS duration, QTc interval), and myocyte action potentials (resting membrane, RM; upstroke velocity, Vmax; duration at 90% repolarization, APD90) at terminal study in 3 groups of dogs (n=6/group): DCM, chronic pace (216 bpm, 4 weeks); DCM/AT-BLOCK, chronic pace and treatment with a specific non-peptide AT1 AT-II antagonist (SR 47436 (BMS 186295); 30mg/kg BID); and control (CON). All measurements were made with the pacemaker deactivated.LVEF (%)LVWS (g/cm2)R-R (ms).QRS (ms).QTc (ms)Week 2:CON68.7±3.2133±14646±9958.4±1.3291±13DCM40.9±4.1*184±16*519±4060.7±1.9316±9DCM/AT-Block44.1±3.7*138±10+540±566.32±1.2*325±9Week4:CON73.1±2.4127±10629±4557.6±1.4314±9DCM35.2±3.5*223±16*505±41*62.0±1.9313±9DCM/AT-Block35.2±2.7*160±13*+578±4865.7±1.5*296±6*p<0.05 vs CON+p<0.05 vs DCMWith DCM, RM (-71±l* vs -78±1mV) and APD90 (257±9* vs 226±7ms) increased, and Vmax decreased (121±5* vs 158±9V/s) compared to CON. In contrast, with AT-BLOCK, RM became more negative (-76±1+mV), APD90 was reduced (183±14*+) and Vmax increased (165±13+).SummaryAT1 AT-II receptor blockade during the progression of DCM caused significant changes in LV myocardial conduction and myocyte action potentials. These results suggest that AT1 AT-II receptor activation plays a contributory role toward the changes in LV electrophysiology with DCM

Phytochemistry, toxicology, and food potential of velvetbean (Mucuna Adans. spp., Fabaceae)

Abstract in English and FrenchIn IDL-1387