Cathodic electrochemical current arrangement with telemetric application

• US 4,883,057 A
• Filed: 09/09/1986
• Issued: 11/28/1989
• Est. Priority Date: 05/09/1984
• Status: Expired due to Term

• Current Assignee: The Research Foundation for The State University of New York (State University of New York)
• Original Assignee: The Research Foundation for The State University of New York (State University of New York)
• Inventors: Broderick, Patricia A.
• Primary Examiner(s): Nguyen, Nam X.
• Application Number:
  US06/905,579
• Time in Patent Office: 1,176 Days
• Field of Search: 128/631, 128/635, 128/731, 128/734, 128/904, 204/1 T, 204/400, 204/403
• US Class Current: 600/302
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/1473 invasive, e.g. introduced into the body by a catheter A61B5/1482 takes precedence
• CPC Class Codes: A61B 5/4076 Diagnosing or monitoring particular conditions of the nervous system A61B5/4821, A61B5/4824 take precedence
• CPC Class Codes: Y10S 128/904 Telephone telemetry

Abstract

This invention relates to a method for producing a cathodic, or reduction, current used in an in vivo semidifferential, semiderivative and/or semiintegral electrochemical method for achieving routine, reliable, and reproducible measurements of the dynamics of neurochemicals and neurochemical-like materials for the purpose of medical diagnosis in the body and brain of animals and in human patients. The method of this invention also permits the detection of biological markers to delineate diseased states for purposes of preventative and therapeutic medicine. Telemetric applications and automated devices for diagnostic and monitoring purposes are also described.

Claims

1. A method for measuring the rate of release and/or reuptake of one or more biogenic chemicals in vivo and in situ in a warm-blooded or cold-blooded animal brain or body comprising:

connecting said brain or body to an electrical circuit comprising;

an auxiliary electrode placed in contact with an outer layer of an organ or sub-organ to be analyzed;

a reference electrode placed in contact with said outer layer of said organ or sub-organ to be analyzed;

an indicator microelectrode which is packed with graphite paste and mineral oil modified with a compound selected from the group of fatty acids, fatty acid derivatives, perfluorosulfonated compounds and salts thereof which is inserted into said organ or sub-organ'"'"'s interior;

a D.C. source and means for forming cathodic current connected between said reference electrode and said indicator electrode;

said organ or sub-organ, auxiliary electrode, reference electrode and indicator electrode thus forming an electrochemical cell which produces output cathodic current;

means connected in series with said reference electrode for semidifferentiating the cathodic current and;

processing the signal which represents the output current as the semiderivative of the linear current function;

thereby producing a cathodic current which represents the rates of release and/or reuptake of one or more biogenic chemicals, the cathodic current enabling the detection of one or more biogenic chemicals which are reduced as well as oxidized and which therefore provides for reproducible results.

2. A method according to claim 1 wherein said biogenic chemicals are selected from the group consisting of amines, amine metabolites, ascorbic acid, amino acids, and neuropeptides.

3. A method according to claim 1 wherein the presence of said biogenic chemicals are measured in the central nervous system after the peripheral administration of a drug.

4. A method according to claim 1 wherein said biogenic chemicals are measured after the central administration of a drug.

5. A method according to claim 1 wherein said cathodic current is transmitted to a receiver telemetrically.

6. A method according to claim 1 wherein a chemical substance is administered to the animal after a reproducible baseline value is achieved.

7. A method according to claim 6 wherein said chemical substance is a neuropsychopharmacological agent selected from the group consisting of antidepressants, neuroleptics, antianxiety agents, anti-panic agents, anti-manic/depressive agents, calcium-blocking agents, agents of addiction, enkephalins, enkephalinamides, endorphins and dynorphin.

8. A method according to claim 7 wherein said indicator microelectrode is a Teflon-coated microelectrode homogeneously packed with graphite paste and mineral oil.

9. A method according to claim 8 wherein said modifying compound is selected from the group consisting of acylglycerols, phosphoglycerides, sphingolipids and waxes.

10. A method according to claim 8 wherein said modifying compound is arachadic acid.

11. A method for diagnosing mental illness comprising measuring levels of biogenic chemicals according to the method of claim 1 and comparing said levels to the levels of said chemicals from healthy individuals.

12. A method of elucidating behavioral determinants by measuring levels of biogenic chemicals using the method according to claim 1 and correlating said levels with physiological attributes.

13. A method according to claim 1 comprising measuring the rates of release and reuptake of at least two biogenic chemicals having approximately identical oxidation potentials and different reduction potentials.

14. A method according to claim 1 for diagnosing and studying brain reward/brain pain systems, euphoria, drug addiction, alcohol dependency, diabetes, self-administration of drugs, stereotypy, catalepsy, antianxiety or anxiety paradigms, turning behavior paradigms, reactions to environmental stimuli, conflict/avoidance paradigms, muricide, memory loss, brain injury, and cervical cancer.

15. A method according to claim 1, wherein semiderivative voltammetry is employed for detecting the production of one or more biogenic chemical peaks which represent neurotransmitter and neurotransmitter-like peptides.

16. A method to claim 15 wherein the biogenic chemical peaks produced are at 150, 290, 520, 690, 790, 820 and 910 mv on a semidifferential voltammogram.

17. A method according to claim 1 for detecting non-electroactive moieties and electroactive moieties which are slow to diffuse, in vivo by attaching antigens to antibodies, the antigen having electroactive moieties.

18. A method according to claim 1 wherein neurochemical profiles from different brain regions are provided.

19. A method according to claim 18 wherein the neurochemical profiles are employed for neurochemical mapping for diagnosis of disease.

20. An electrical circuit capable of analyzing the concentration of one or more biogenic chemicals in vivo comprising:

an auxiliary electrode for placing in contact with an outer layer of an organ or sub-organ to be analyzed;

a reference electrode for placing in contact with said outer layer of said organ or sub-organ to be analyzed;

an indicator microelectrode which is packed with graphite paste and mineral oil modified with a compound selected from the group of fatty acids, fatty acid derivatives, perfluorosulfonated compounds and salts thereof, for inserting into said organ or sub-organ'"'"'s interior;

a D.C. source and means for forming cathodic current connected between said reference electrode and said indicator electrode;

whereby said organ or sub-organ, auxiliary electrode, reference electrode and indicator electrode form an electrochemical cell which produces output cathodic current; and

means connected in series with said reference electrode for semidifferentiating the cathodic current.

21. The circuit of claim 20 wherein said means for semidifferentiating the cathodic current comprises a differential operational amplifier including a ladder network of resistors and capacitors.

22. The circuit of claim 21 wherein said means for controlling comprises an operational amplifier.

23. The circuit of claim 22 wherein the circuit further comprises a reduction amplifier connected in series with said means for semidifferentiating.

24. The circuit of claim 23 wherein said means for receiving said telemetrically transmitted signals comprises a dual antenna network comprising two parallel branches, each branch comprising in series one or more radio frequency amplification stages, a mixer stage, one or more intermediate frequency stages, and a local oscillator connected to both mixer stages to provide uniformity in the intermediate frequency.

25. The circuit of claim 24 further comprising means connected to outputs of said dual antenna network for providing an analog current signal, and means for visually displaying said signal.

26. The circuit of claim 20 further comprising a reduction current amplifier connected in series to the output of said means for semidifferentiating the cathodic current, said reduction current amplifier having output terminals on which measurements can be made which are indicative of the instantaneous rate mechanism of said biogenic chemicals in an organism.

27. The circuit of claim 26 further comprising a current measuring operational amplifier connected between said indicator electrode and ground.

28. The circuit of claim 27 further comprising an operational amplifier connected between said indicator electrode and said auxiliary electrode, and another operational amplifier connected between said indicator electrode and said reduction current amplifier whereby an output which produces a linear trace on an analog recorder may be obtained from said reduction current amplifier.

29. The circuit of claim 20 further comprising means for controlling the electrical potential of said auxiliary electrode, said means for controlling being connected to said auxiliary electrode and to ground.

30. The circuit of claim 29 further comprising a follower operational amplifier connected between said reference electrode and ground.

31. The circuit of claim 20 further comprising means for telemetrically transmitting signals proportional to said cathodic current and means for receiving said transmitted signals.

32. The circuit of claim 20 wherein said means for differentiating the cathode current comprises a differential amplifier.

33. The circuit of claim 20 further comprising means for automatically operating said circuit.

34. The circuit of claim 33 wherein said automatically operated means comprises a transistor-transistor logic connected to said means for initiating scans and regulating the voltage level of said scans.