Biomedical subjects

D B Talley

Publications and source records attributed to D B Talley.

3 recordsLinked to original sources

PubMed1991

Electrochemiluminescence detection for development of immunoassays and DNA probe assays for clinical diagnostics.

Electrochemiluminescence (ECL) has been developed as a highly sensitive process in which reactive species are generated from stable precursors (i.e., the ECL-active label) at the surface of an electrode. This new technology has many distinct advantages over other detection systems: no radioisotopes are used; detection limits for label are extremely low (200 fmol/L); the dynamic range for label quantification extends over six orders of magnitude; the labels are extremely stable compared with those of most other chemiluminescent systems; the labels, small molecules (approximately 1000 Da), can be used to label haptens or large molecules, and multiple labels can be coupled to proteins or oligonucleotides without affecting immunoreactivity, solubility, or ability to hybridize; because the chemiluminescence is initiated electrochemically, selectivity of bound and unbound fractions can be based on the ability of labeled species to access the electrode surface, so that both separation and nonseparation assays can be set up; and measurement is simple and rapid, requiring only a few seconds. We illustrate ECL in nonseparation immunoassays for digoxin and thyrotropin and in separation immunoassays for carcinoembryonic antigen and alpha-fetoprotein. The application of ECL for detection of polymerase chain reaction products is described and exemplified by quantifying the HIV1 gag gene.

2,2'-Dipyridyl↗

PubMed1990

Potentiometric biosensor employing catalytic antibodies as the molecular recognition element.

Catalytic antibodies are introduced as an important new class of biomolecules for molecular recognition in biosensors in which the binding sites are continually regenerated by the catalytic reaction of the substrate. Consequently, molecular recognition by catalytic antibodies can yield reversible immunoblosensors. In this example, a prototype potentiometric biosensor is described in which a micro-pH electrode is modified with a catalytic antibody that catalyzes the hydrolysis of phenyl acetate, producing hydrogen ions that can be monitored by the electrode. The reversible response is linear with the log of substrate concentration over a range of 20-500 microM with a detection limit of 5 microM under the conditions of this study. Alternative applications of catalytic antibodies in other biosensor configurations are discussed.

Antibodies, Monoclonal↗

PubMedDate not supplied

Computer-aided characterization and optimization of the Thumper compression waveform in closed-chest CPR.

Optimization of blood flow and blood pressure is critical for a positive outcome of cardiopulmonary resuscitation (CPR). The use of models can facilitate the analysis of different methods of performing CPR. Programming with SPICE software, the authors modified a hardware model electrically equivalent to the human cardiovascular system into a software model to analyze and predict the hemodynamic output parameters of different compression waveform inputs used in thoracic pump CPR. Thumper waveforms produced with the computer model predicted the same decaying frequency response as those found in other studies with humans and a recording manikin in which the generated pressures decreased with increased compression rates from 60 to 140 cycles/min. Using a square-wave input having a flat frequency response, the model predicted a constant diastolic pressure and a steady increase in systolic pressure from 94 to 109 mmHg while increasing compression rate from 60 to 140 cycles/min at a constant 50% duty cycle. Blood flows predicted with the use of a square-wave compression input were greater than the flows predicted with the use of a Thumper waveform, and increased with an increase in compression rate. The model also predicted increased mean systolic pressure when the duty cycle increased from 20% to 80% while diastolic pressure decreased slightly. Although mean systolic pressure increased with increased duty cycle, the model predicted a decrease in coronary flow at the higher duty cycles of all compression waveforms. Increases of 75% to 100% in systolic pressure and blood flow were produced when increases in chest compression force and the rapidity of the rise time, termed "spike-impulse" CPR, were simulated.

Blood Pressure↗