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.     

Behavior of artificially produced holes in lung parenchyma

Spherical and cylindrical holes were cut in the parenchyma of isolated dog lung lobes. The holes were insufflated with tantalum dust and the hole diameters were measured along the deflation limb of the lobe pressure-volume curve from transpulmonary pressures of 20 to 0 cmH2O. Hole volume as a fraction of lobe volume was found to be independent of transpulmonary pressure. The hole volume relative to the amount of tissue removed was used to determine the displacement at the hole boundary. A comparison of this displacement with the displacement predicted by a continuum mechanics analysis provides evidence for the applicability of the methods of continuum mechanics and further evidence that the shear modulus of the parenchyma is relatively small.     

Lymphocytes and cells in malignant transformation: similarities and possible relationship between the two cell types

This paper points out some similarities between the behaviour and characteristics of lymphocytes and their transformation to lymphoblasts on one hand and malignant cells on the other. The areas of similarity are (1) anomalous communicating junction formation; (2) recruitment of neighbouring cells; (3) random antigen expression; (4) Fc synthesis; (5) stimulation by immune attack; (6) relation to a plasminogen activator, and (7) inhibition of stimulation by trypsin inhibitors. It is argued that, considering the anomalous membrane characteristics shown by lymphocytes and malignant cells and the list of similarities, carcinogenesis could represent a normal cell line infected with lymphocytic information. Two incidental ideas are presented based on the main idea. These concern lymphocytes but are related to malignant cells and their characteristics too. They are (1) a mechanism whereby generation of randomness in the variable region of Ig molecules could take place, and (2) a mechanism whereby the lymphocyte, in order to kill its target, could use the normal cell's propensity to form communicating intercellular junctions.     

Exit block of artificial pacemaker induced by carotid sinus massage

Failure of the pacemaker is a common complication of pacemaker therapy. Identification of the disorder responsible for the failure to pace is often difficult. An increase in myocardial threshold can result in nonconduction of the artificial impulse, particularly near the end of the life of the battery, when the output of current has started to decline. This report demonstrates such an increase in myocardial resistance which was apparent only upon massage of the carotid sinus.