The effect of external pressure on skin temperature distribution by thermography

1) Serial thermograms were taken after the application of various intensities and durations of localized pressure on the medial surface of the human forearm. 2) Thermal response of the body surface to localized pressure was quantified. 3) It was found that usually a time period of between 1 to 3 minutes elapsed before the body surface attained a maximum elevation of temperature from the time the localized pressure is removed. 4) It was found that increased intensity of pressure (5 psi vs. 3 psi) and longer duration (20 minutes vs. 10 minutes) caused larger thermal responses. 5) It is suggested that high resolution medical thermography may eventually become a useful tool in the fitting of prosthetic and orthotic devices and for the prediction of pressure sores formation so prophylactic measures can be started immediately on immobilized patients.     

Impermeant maleimides. Identification of an exofacial component of the human erythrocyte hexose transport mechanism

The facilitated diffusion of D-glucose across human erythrocyte membranes requires an exofacial (outer surface) sulfhydryl group which can be alkylated by the impermeant reagents glutathione-maleimide and dextran-maleimide. The irreversible inhibition produced by these reagents is asymmetric; inhibition of glucose efflux considerably exceeds that of influx when transport is assayed in the absence of glucose on the opposite side of the membrane. Both D-glucose and cytochalasin B protect the exofacial transport site from alkylation by the impermeant maleimides. This masking effect provides the basis for a two-step procedure for differential labeling of the outer transport site with radioactive glutathione-maleimide. The method labels clearly and consistently a component of the membrane proteins which migrates in sodium dodecyl sulfate-polyacrylamide gels between Coomassie brilliant blue-stained Bands 4.2 and 5, corresponding to an apparent molecular weight of 65,000 to 70,000. Transport studies after inhibition with N-ethylmaleimide suggest that the hexose mechanism also requires a second sulfhydryl group which is not accessible at the cell surface.