William. C. Lawrie's scientific contributions

Ten amniotic fluid samples obtained from third trimester pregnant women suffering from insulin dependant diabetes mellitus were analysed by 1H-NMR and compared to ten samples from a group of normal volunteers. A subset of the metabolites identified; valine, lactate, alanine, acetate, citrate and glucose were quantitated using standard addition methods. Apart from valine and citrate, a general diminution in the concentration of each of these species was found, especially glucose, in the diabetic group. The abnormally low glucose levels in the diabetic group are suggestive of infection in the patient group. However, the depressed lactate levels in the diabetic group suggest that in these cases the fetus was not subjected to stress.

Alterations in the mobility of the components of the cell membrane occur via a number of different mechanisms and as a response to different classes of bio-molecules which are present due to disease, diet or therapy. For example, toxins such as reactive oxygen species react at unsaturated carbon-carbon bonds facilitating the formation of crosslinks, inducing lipid cleavage and in some cases the formation of blebs on the membrane surface [1]. Messenger species, such as thyroid stimulating hormone (TSH) alter the constituents of the lipid bilayer by increasing the phosphatidylcholine: phosphatidylethanolamine ratio in the membrane and increasing the degree of unsaturation in the lipid bilayer [2]. Passive molecules, such as long chain fatty acids (LFA), interpolate into the membrane and affect the ability of the natural lipids to tumble and translocate within the bilayer [3]. Finally, the pathology of malignancy, also includes changes in cell membrane structure and function [4]. Assessing these changes in the cell membrane can be achieved by scanning electron microscopy (cell shape), viscometric methods (shear stress) and fluorescent probes (membrane fluidity). Whereas the former two assessments are a function of the whole cell, it is becoming clear that motion within the bilayer can be regional (e.g. cytosolic and plasma surfaces, fatty acid core & periplasmic space) and non-uniform and that fluorescent probes offer only a narrow targeted view of the events in progress.