Charles Sheard

THE COLOR OF THE SKIN AS ANALYZED BY SPECTROPHOTOMETRIC METHODS: III. The Rôle of Superficial Blood.

Variation in the superficial blood supply undoubtedly plays a more important r6le in the production of changes in the color of the skin than does an increase or decrease in the pigment. This accounts for the difference in subjects who are fairly well matched otherwise with regard to content of cutaneous pigment. In general, the pigment, in proportion to its amount, prevents the superficial blood from attaining visibility. Changes in color in the brunet, attributable to alterations in the circulation in the skin, are less noticeable than the same changes in the blond, and in the negro they are practically negligible. This holds true for the skin of the same thickness, it being quite obvious that the skin of the palms or soles or other hyperkeratotic areas will permit less light to penetrate than will the thin covering of the malar prominence or the dorsum of the hand. The color which the blood imparts to the skin is directly related to the amount or quality of the blood present in the peripheral vessels. The size of the arteries, capillaries, and venules varies with the degree of pressure behind them and with the volume of blood to be accommodated. In conditions of hypertension one would expect more force to be exerted peripherally than normally. In the dependent areas of the body, such as the legs and hands, the elements of gravity and stasis of sluggish flow are added. In cases in which the total blood volume

Relation of Basal Metabolic Rate to Vasodilatation and Vasoconstriction of the Extremities of Normal Subjects as Measured by Skin Temperatures

Various indirect methods of measuring blood flow in the peripheral blood vessels of man are available. Irrespective of the method used for measuring blood flow, certain fundamental factors concerned with the status of the subject or patient influence the measurement of blood flow. These factors are environmental temperature, position of the extremities and food. The present investigation indicates that a consideration of the basal metabolic rate or basal heat production is another important factor.

The effect of X-Rays on the electric potentials and the rate of oxidation of frog's skin

In a previous investigation, W~sL~A~s studied the effect of x-rays on the potent ial difference across frogs skin for a period of t ime following a lethal dose of irradiation. During the present investigation a smaller dose, which was not lethal, was used, and the effect produced was determined at intervals for a month following irradiation, iS was suggested in the previous report tha t the changes in potent ial difference were indicative of similar changes in the rate of oxygen consumption. In the present investigation measurements were made to test this assumption.

The electrophoretic characteristics of streptococci

It is possible to produce changes in the cataphoretic distribution of streptococci by means of a high frequency electric field. Successive increments of exposure to high frequency energy produce cyclic or periodic changes in the cataphoretic distributions of the treated suspensions of streptococci. The changes produced in the cataphoretic distributions of streptococci exposed to a high frequency field are maintained in the subcultures of these organisms.

The electrophoretic characteristics of streptococci: II. The effects of intravenous injection into rabbits of strains of streptococci which have been exposed to the high frequency field

Strains of streptococci, in which alterations in cataphoretic velocities have been produced by exposure to a high frequency field, when subsequently injected into rabbits are found as frequently in certain tissues as are control (unexposed) strains. Irrespective of the type of cataphoretic distribution of the injected strain, the streptococci which are isolated from brain tissue exhibit a type of cataphoretic velocity distinctly different from the organisms which are isolated from joint tissues.

Thermal Changes Produced in Tissues by Local Applications of Radiothermy

Summary It is apparent that errors in the measurement of temperature, due to the presence of a metallic needle (thermocouple, without leads) in tissue during exposure of that tissue to a high frequency electric field are greater when the time of exposure is short and when the intensity of the electric field is low. The relationship of the heat produced in deep-lying tissues to the heat produced in superficial tissues is dependent on the distance at which the condenser plates are placed with respect to the locations of the tissues. This fact is of importance in the therapeutic uses of high frequency fields (radiotherms). When a considerable air space separates these plates from the surface of the tissue, the change in temperature produced in the deep-lying intra-articular tissue is greater than that produced in the subcutaneous tissue. The converse relationship maintains when the plates are placed close to the surface of the tissue. This dielectric layer effect is superimposed or any specific heating due to difference in constitution of tissue and variation in wave length of radiation which may be present. Schliephake 1 , 2 first demonstrated this type of depth effect of the high frequency field, and has presented experimental evidence which indicates that high frequency treatment plates which are allowed to make contact with the surface of tissue produce a tissue heating which is closely comparable with that of diathermy, in which the production of heat is predominantly in the superficial layers of tissue. The experimental evidence presented clearly demonstrates that it is possible to produce abnormally high temperature in a chosen region (i. e., knee joint of a dog) by means of local applications of short wave electric energy of sufficient intensity.

Changes in Electric Potentials and Rates of Oxidation of the Skin Subsequent to Roentgen Irradiation1

IN most of the experimental work which has been done on the effects of irradiation with roentgen rays on biologic materials, an end-effect only, or the effect at one definitely specified time after the irradiation, has been investigated. The purpose of the investigations now being reported was to determine the variations in the physiologic quantities of frogs skin, namely, the electric potential difference across the skin and the rate of consumption of oxygen of the skin as dependent on the time after irradiation. Other investigations have shown that there is some relation between the electric potentials and the rate of consumption of oxygen and that the magnitude of the potential difference may be taken as a “measure of life” or of the vitality of the skin. The literature regarding the correlation in living organisms between metabolic and electric gradients has been reviewed and additional evidence brought forth in papers by Child (3), Child and Hyman (4), and Hyman and Bellamy (8). The results of the m...

Changes in Temperatures of Tissues After Systemic Applications of Short Wave Electric Fields

Conclusions These experimental data show that, in living animals, the temperatures of certain different types of tissues are affected to different degrees by the systemic application of the shortwave electric field. Muscle tissine is affected slightly more than is subcutaneous tissue : intra-articular tissue is affected more than is muscle tissue. Furthermore, it has been shown that the reactions of anesthetized animals to general hyperthermia produced by this physical agent (short electric nave fields) are quantitatively different from those produced in unanesthetized animals. Measurements of temperatures of tissues of dead animals have shown that bone is heated much more markedly than is muscle tissue and they have indicated that the changes of temperature produced by this high frequency field are strictly dependent on the position and constitution of the various tissues.