Biomedical subjects

B L Lawson

Publications and source records attributed to B L Lawson.

3 recordsLinked to original sources

PubMed1997

Breath timing, volume and drive to breathe in conscious rats: comparative aspects.

In conscious animals, respiratory frequency (f) and tidal volume (VT) vary breath to breath. Examining the average value of variables associated with specific bins of another variable, such as breath f, provides a unique tool to examine respiratory behaviour. In conscious Sprague-Dawley rats respiratory breath timing, tidal volume (VT) and drive (VT/TI) were characterized using a plethysmograph. In the majority of rats at low breath f, expiratory time (TE) exceeded inspiratory time (TI) and these times became equal as f exceeded 150 breaths/min; there was no evidence for TI greater than TE at higher f, as observed in cats and dogs. When VT is normalized per kg, rat breath VT and VT/TI, binned by breath f, are continuous with those for the cat and non-panting dog at the lowest breath f. Relative to breath f, breath VT and VT/TI in rats are greater than in normothermic panting dogs (20 degrees C), but only slightly greater than those variables in panting dogs in the heat (30 degrees C). Lower values of breath VT/TI, binned by breath f or V, in cats and dogs are compensated for by a greater TI relative to the duration of a given breath. This comparative analysis suggests continuities of respiratory pattern generation among species.

Animals↗

PubMed1988

A formate based precursor for the preparation of technetium complexes.

Tc-formate complexes have been prepared by electrolytic, stannous, and borohydride reduction of pertechnetate in formate buffer. Individual Tc-formate complexes were isolated from reaction mixtures with silica bonded phase anion-exchange HPLC. The predominate air stable red Tc-formate complex has a negative charge, an absorption maximum at 536 nm, and a molecular weight between 100 and 300 dalton. The isolated major Tc-formate complex was found to react with isocyanide, diphosphonate, and various nitrogenous ligands. The relevant use of Tc-formate complexes as synthetic precursors to other technetium complexes is seen as being beneficial to the understanding of technetium ligand substitution.

Chemical Phenomena↗

PubMed1982

Analytical problems facing the development of electrochemical transducers for in vivo drug monitoring: an overview.

Even though significant progress has been made in the development of electrodes for the in vivo detection of catecholamines, oxygen, and various cations, there has been little research on the feasibility of continuously monitoring drugs in whole blood by electrochemical sensing devices. Electroanalytical problems associated with the development of such electrochemical transducers include the need for increased sensitivity and specificity, decreased biological matrix interferences, more rapid response times, improved miniaturization, and more reliable calibration procedures. We present a critical evaluation of potentiometric, conductometric, and amperometric techniques, with a brief review of basic principles and recent advances in ion-selective electrodes, chemical-sensing field-effect transistors, amperometric enzyme electrodes, and electrochemical immunosensors.

Drug Therapy↗