US2298506A - Method for exploring living tissue - Google Patents

Description

Oct. 13, 1942. L. w. PARKER METHOD FOR EXPLORING LIVING TISSUE Filed Jan. 25, 1940 INVENTOR. Low; 14/ Rm if 44/! /g ATTORNEYS Patented Oct. 13, 1942 t 2,298,506

2,298,506 METHOD FOR EXPLORING LIVING TISSUE Louis W. Parker, Woodside, N. Y., assignor of onehalf to Karl Binkovitz, New York, N. Y.

Application January 25, 1940, Serial No. 315,497 1 Claim. (Cl. 128-21) My invention relates to a new and improved of any conducting material. The electrode may method and device for exploring living tissue, be an ordinary steel rod. It may be made of a including the tissue of a human being. non-rusting metal or alloy, such as platinum,

One of the objects of the invention is to eX- stainless steel, etc. The other terminal of the plore tissue located underneath the skin, and secondary coil 2 is connected to one side of a more particularly tissue located directly undercondenser 3, whose capacity may be a microneath the inner layer of the human skin. This farad. The other side of the condenser 3 is consubcutaneous tissue has blood vessels. nected to a terminal 8. The terminal 8 and a Another object of the invention is to provide second terminal 9 are connected in parallel. One an improved method and means for diagnosing 10 pair of legs of this parallel circuit has the the allergy of a patient to a substance or subrectifiers 4 and 4a and the other pair of legs stances. has the rectifiers 4b and 40. These rectifiers Another object of the invention is to provide may be of any suitable type, such as copper oxide improved means and method for determining rectifiers. As indicated by the arrows, the rectivarious gland conditions, the reaction of the fier 4 transmits current only in a direction from patient to glandular extracts and the like. the terminal 8 towards the terminal 9 and the Another object of the invention is to provide rectifier 4a transmits current only in the opposite electrical means, whose reading is unafiected by direction. The rectifier 4b can transmit current the direct currents which are generated in varionly in a direction from the terminal 9 to the ous parts of a living organism, and more parterminal 8, and the rectifier 40 transmits current ticularly the human being. only in the opposed direction.

Other objects of the invention will be stated The medium points [0 and l l are connected to in the annexed description and drawing which a suitable microammeter 5. In efiect, the cirillustrates preferred embodiments thereof, it becuit has four legs between the points 8, I 9, 9, ing understood that the above statement of the and II. Each of these legs has a rectifier. These objects of my invention is intended to generally legs are substantially or wholly identical. The explain the same without limiting it in any terminal 9 is connected through a resistance 6 manner. to a second electrode 1a, which is preferably Fig. 1 is a circuit diagram of one embodiment identical in all respects with the electrode 1. The of the invention. resistance 6 may be quite high, such as 20.000

Fig. 2 is a circuit diagram of a second embndiohms, ment of the invention. When the points of the electrodes 7 and la are Fig. 3 is a circuit diagram of a third embodi applied to the subcutaneous living tissue, alterment of the invention. hating current can flow in one direction from the Heretofore, in determining allergic diseases or 30 upper terminal of secondary coil 2, through the reactions, it has been customary to apply test condenser 3, to the terminal 8, through the rectisubstances or solutions to the skin and then to fier 4, to the terminal I9, through the meter 5 to observe the condition of the outer surface of the point H, through rectifier to terminal 9, and skin. This method was superficial and uncertain. through the resistance 6 to the electrode or According to the improved method, the condition 40 conducting member 1a. When the current is of the living tissue underneath the innermost flowing in this direction, it will not flow from layer of the skin is reliably and carefully tested. the terminal II! to the terminal 9. Likewise it Fig. 1 shows the primary coil 1 of a transwill not flow from the terminal 8 to the terminal former which can be connected to any suitable H. During the next half-cycle of the induced source of alternating current. This current may alternating current of the secondary coil 2, the be the usual sixty cycle current, whose voltage direction of the current is reversed. Current will is 110 volts. The voltage and the frequency of then flow from the electrode la through the rethe primary current may be varied Without limisistance 6, to the terminal 9, through the rectitation, but it is preferable to use a current havfier 4a to the terminal I, through the meter 5 ing a relatively low frequency. An alternating to the terminal ll, through the rectifier 4b to current is induced in the secondary coil 2 of the the terminal 8, and through the condenser 3 to transformer. The R. M. S. voltage at the end the upper terminal of the secondary coil 2. The of the secondary coil may be about 2.5 volts. condenser 3 blocks the flow of direct current One terminal of the secondary coil 2 is connected which may be flowing in the living tissue between to the electrode 1. This electrode may be made 5 the points or the electrodes 1 and la so that the meter reading is a substantially direct and accurate reading which measures the amperage of the alternating current which is passed through the subcutaneous living tissue between the points of electrodes 1 and 111, although the meter is of the direct current type. The meter 5 can be of any suitable type which can measure the flow of direct current.

In order to diagnose allergic diseases, the points of the electrodes 1 and la are forced lightly through the skin of any suitable part of the body, until said points contact with the tissue underneath the skin and the blood vessels of said subcutaneous tissue. This may be done on the arm of the patient, and the distance between the points may be approximately .one centimeter. It is preferable to take the reading or readings, by measuring the resistance of the tissue directly underneath the innermost layer of the skin. Under the conditions above mentioned the reading of the ammeter or other meter 5 will show a normal current flow or 12-13 microamperes.

A scratch is then made upon the skin between the electrodes, and the material to be tested is then placed in said scratch, so that it will act uponthe tissue directly underneath the innermost layer of the skin. This scratch preferably extends wholly through the various layers of the skin. The test material is preferably a liquid extract of the food or substance which is being tested. It consists preferably of an isotonic solution. This test material may be of the standard types which are now used for testing allergic conditions.

If the patient is test material, this will manifest itself by a rapid lowering of the resistance between the points of the test electrodes. The meter 5 will quickly record a current or" about 50 microamperes.

Tests can therefore be made with foods, dusts, pollens, spores and molds, and cultures of various bacteria, such as Staphylococcus aureus and Albus aureus.

The material to be tested need not necessarily be in the liquid condition, or in the form of a solution or dispersion or culture, as long as the test material can react with the living tissue. 1 can likewise use extracts of various glands, and more particularly extracts of the ductless glands, in order to measure the activity of the corresponding glands in the living organism. For example, liquid thyroid extract canbe utilized. A rapid lowering of the resistance of the living tissue between the test points will indicate a hypothyroid condition.

It is well known tween various portions thatdirect currents flow beof the human body, but these direct currents are blocked by the condenser 3 so thatthey do not affect the accuracy of the reading. The circuit preferably has minimum inductance, save for the inductance of the secondary coil 2. However, the circuit may have inductance additional to the inductance of said secondary coil 2, without departing from the invention. The transformer may have an iron core, or else I can use a transformer which does not have an iron core, in order to minimize the inductance of the test circuit.

If the patient does not react unduly to the test substance, there will be little or no change in the reading of the meter. The test points may be used for measuring the resistance of a substantial cross-sectional area of the tissue, such as a cross-sectional area of two to three square centimeters, since the current penetrates the allergic or susceptible to the subcutaneous tissue, including its blood vessels to some extent. The distance between the points of the electrodes is about one-half inch, although this may be varied. The instrument may be used for exploring living tissue, a centimeter or even more below the inner surface of the outer skin. It is unnecessary to insert the points of the needles more deeply because the current penetrates the tissue inwardly of the points of the needles.

If the patient is allergic or sensitive to the test substance, the blood will inflate the blood vessels in tissues in the test area, below the skin of the arm, thus lowering the resistance between the points of the electrodes.

While I prefer to block the direct current of the living tissue from the measuring instrument 5, in order to eliminate the resultant error, the invention is not limited to this and the invention is not necessarily limited to the use of alternating current, although such current is highly preferred.

I prefer that the scratch which is used for causing contact between the test substance and the living tissue should extend completely through the various layers of the skin.

The rectifiers 4-40 constitute full-wave rectifying means and they can be replaced by other suitable full-wave rectifying means so that current pulses are passed through the measuring instrument 5 in the same direction.

In its broadest aspect, the invention includes the use of any type of electric current, including current pulses in the same direction, or current pulses in successive opposed directions. It is preferred to eliminate from the measurement the direct current which is self-generated in the living tissue. The substance which produces the change in electrical resistance may be administered in any manner.

Likewise in determining many conditions, the measurement of the electrical resistance of living tissue is sufiicient, as comparison can be made with the resistance of tissue under normal conditions. Under such circumstances, it is not necessary to administer or to apply a test substance.

Instead of using contact needles which are applied to the tissue underneath the skin of the arm or other part of the body, I can use electrodes having contact discs. Each said disc may have a diameter of about of an inch. These discs are applied to a mucous membrane, such as the mucous membrane of the nose. It is unnecessary to pierce this mucous membrane. The reading which is thus secured directly on the outer surface of the mucous membrane may be used as a norm reading, which may be used independently of the norm reading secured on the tissue underneath the skin of the arm or the like. These respective norm readings may also be compared.

The mucous membrane of the nose is similar to the skin of the arm, but the thickness and resistance of the skin of said mucous membrane are negligible. The reading which is therefore secured at the exposed outer surface of the mucous membrane of the nose, without penetrating said mucous membrane, is steady and gives a definite and clear norm for the respective individual. This provides simple and easy means for standardizing the instrument.

In making a test on the tissue under the skin of the arm, for example, in order to establish a norm for the particular patient, experience has shown that the first reading between the first pair of selected points of the tissue is usually too high. After making this first test, a series of additional tests are made quickly at other pairs points of the arm, so that the current is passed through about eight or ten diiTerent pairs of selected points of the arm.

The test is nOW repeated at the first pair of selected points, and the reading is usually lower than the initial reading. This final reading, which is the lowest that can be secured, is taken as the norm.

The test on the mucous membrane of the nose can be used as a check on this norm reading taken on the arm.

In the embodiment shown in Fig. 2, the coils I I, I2, I4 and I5 are inductively coupled to a primary coil which is similar to the coil I. This primary with an alternating current The secondary coil I I has a ground connection I6 which divides the same into equal sub-coils I Ia and Ill), each of which has a root mean square (R. M. S.) voltage of 90 volts. The coil I2 delivers an R. M. S. voltage of 5 volts. The coil I 3 has one end thereof grounded. It delivers an R. M. S. voltage which can be varied between zero and 25 volts. I5 is grounded at its centre. It delivers an R. M. S. voltage of 6.3 volts.

The capacity of the condenser I8 is one microfarad (1 mid.) This is preferably a paper condenser. Each of the condensers I 9 and 20 has a capacity of 16 microfarads. and 20 are preferably electrolytic condensers. The electrode or disc 7a is grounded at 2|, through a resistance 22 which is equal to 20,000 ohms. The resistances 23, 24 and 25 are respectively 5,000 ohms, 7,000 ohms, and 15,000 ohms. The microammeter 26 can read from zero to 1000 microamperes. The wire 27 is connected to the central point of the secondary coil I2. One terminal of the microammeter 26 is connected through the resistance 24' to the wire 27 after the resistance 23, and the other terminal is connected to the central point or other selected point of the resistance 25.

The coil I2 heats the filament 28 of a fullwave electronic tube rectifier, which has the plates 29 and 30. Positive current therefore tral point of the coil I I is grounded at IIS, this completes the circuit of the microammeter 26, which is independent of the resistance of the tissue. Each of the condensers I9 and 20 has one side thereof connected to the ground at 25a.

the other side thereof connected by the wire 27a to the point 27b of the rent through the microammeter 26.

The coil I5 heats a filament I7 which heats the cathode 33 of an electronic tube. One endof the cathode 33 is connected at These condensers I9 an adjustable point p 33a of the resistance 25 so as to impart a slight positive bias or voltage to. the cathode 33. Since the grid 32 is grounded through the resistance 22, the grid receives a corresponding predetermined negative bias so that normally only a slight current passes from the plate 3| to the cathode 33. The internal resistance of the electronic tube forms one leg of a circuit which is similar in principle to a Wheatstone bridge.

26 are connected to the neu this purpose, the point 25a may be adjusted along the resistance 25.

The current divides at the point 23a. Part of said current goes through the resistance 24 and through the electronic tube to the cathode 33, then to the point 33a, and then through a portion of the resistance 25 to the ground at 25a. The other part of the current passes through the two portions of the resistance 25 which are located respectively between the Wire 27 and the point 26a, and between the points 2611 and 33a. That part of the resistance 25 which is between the ground connection 25a and the common to both legs of the circuit.

The ungrounded end of the coil I4 is connected to the electrode 7 through the condenser I8. The electrode 7a is connected to the grid 32 and it is also connected to the ground at 2I, through the resistance 22.

When the circuit between the electrodes 7 and 7a is closed through the human tissue, there will be a voltage drop between the points of the electrodes 7 and 7a, depending upon the resistance of the human tissu between the points of these electrodes. There will be another voltage drop across the resistance 22, to the ground connection 2I.

through the meter 26. I

In each of the condensers 3 or I8 a coil 45. coupled to a coil 4i, microammeter 42.

This is inductively which is connected to a Since it is desirable to use tive alternating current meter, instead of a direct current meter. The coil 2 any suitable generator of alternating current. Since the direct current which may be self-generated between the points to which the electrodes land 1a are applied, is constant in direction and substantially constant in value, such self-generated direct current will not affect the reading of the meter 42. Instead of using an inductive coupling between the circuit of the electrodes and the circuit of the meter, I can use capacity coupling. Likewise, the terminals of the meter circuit can be connected directly to the ends of the coil 40, because the voltage drop across the coil 40 will vary with the A. C. voltage drop between the points, of the electrodes 1 and 1a. The resistance of the coil 40 is negligible, so that under such conditions, the reading will not be affected by any voltage drop of the direct current. is used between the circuit of the electrodes and the circuit of the meter in Fig. 3, it will be necessary to insert a blocking condenser of suitable capacity in the circuit of the meter 42.

I have shown preferred embodiments of my invention, but it is clear that numerous changes and omissions can be made without departing from its spirit.

For example, the measuring instrument need not be one which has a scale. It can be any device which will indicate a change in electrical re sistance.

I-Ieretofore, pure distilled water has been used in preparing the solutions Or dispersions or suspensions of the test materials, such as pollens, dusts, particles of food, etc. Some of these substances, such as white wheat flour, will form a stable and uniform mixture with distilled water, in the form of a very thin paste. Other test materials, such as heavy dust, will settle rapidly in the distilled water.

I prefer to increase the conductivity of the distilled water by dissolving a salt or salts therein, so as to produce an isotonic solution, whose osmotic pressure is substantially equal to that of the blood serum. I may dissolve a single salt, such as sodium chloride, in the water. I prefer to dissolve sodium chloride, potassium chloride. and calcium chloride in the distilled water. The use of a plurality of salts makes it possible to further increase the conductivity of the solution, without exceeding said limit of osmotic pressure. The use of an isotonic solution is preferred, but the invention is not limited thereto.

Without limiting the invention to the practical formula which is given as an example, I dissolve in cc. of water about 0.9 gm. of sodium chloride, and equivalent amounts of the other two salts, namely, potassium chloride and calcium chloride, in the proportions of their respective molecular weights, so that each dissolved salt will exert the same osmotic pressure.

Since the total osmotic pressure of the salt solution is equal to that of the blood, it I use a single salt or a plurality of salts, little or none of the salt solution will pass into the blood stream except through the scratch. The use of the salt solution will increase the reading, thus facilitating the observation.

The salts are examples of ionizable materials which can be dissolved in water.

I claim:

A method of determining the effect of a test substance upon a patient, which consists in applying the test substance to the outer walls of the blood vessels of the patient at a selected part of the tissue of the patient, inflating the blood vessels in said selected part by means of said test substance so as to lower the electrical resistance of the blood vessels in said selected part, passing an alternating current through said selected part by means of electrodes whose tips substantially contact with the outer walls of said blood vessels so that the resistance to the passage of the electric current is substantially the resistance of the blood vessels, measuring the decrease in the resistance of said blood vessels which results from the application of the test substance, while substantially eliminating the effect of any self-generated current of the tissue from said measurement.

LOUIS W. PARIQER.

Images