Patents by Inventor David A. Borkholder

David A. Borkholder has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6377057
    Abstract: Biologically active compounds are classified according to their effect on ion channels, changes in membrane potential and ionic currents, and the frequency content of action potentials that the compound(s) evoke in excitable cells. The spectral density changes of such evoked membrane potential or action potential are a characteristic for each channel type that is modulated by the test compound. A pattern of spectral changes in membrane potential is determined by contacting a responsive cell with a compound, and monitoring the membrane potential or ionic currents over time. These changes correlate with the effect of that compound, or class of compounds, on the ion channels of the responding cell. This pattern of spectral changes provides a unique signature for the compound, and provides a useful method for characterization of channel modulating agents.
    Type: Grant
    Filed: February 18, 1999
    Date of Patent: April 23, 2002
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventor: David Borkholder
  • Publication number: 20020034745
    Abstract: An apparatus for determining a threshold value (e.g., a threshold cycle number or a time value) in a nucleic acid amplification reaction comprises a detection mechanism for measuring, at a plurality of different times during the amplification reaction, at least one signal whose intensity is related to the quantity of a nucleic acid sequence being amplified in the reaction. The apparatus also includes a controller in communication with the detection mechanism. The controller is programmed to perform the steps of deriving a growth curve from the measurements of the signal; calculating a derivative of the growth curve; identifying a characteristic of the derivative; and determining a threshold value associated with the characteristic of the derivative. Embodiments of an apparatus for determining a starting quantity of a nucleic acid sequence in a test sample are also provided.
    Type: Application
    Filed: March 14, 2001
    Publication date: March 21, 2002
    Applicant: Cepheid
    Inventors: William A. McMillan, Lee A. Christel, David A. Borkholder, Steven J. Young
  • Publication number: 20020034746
    Abstract: A computer program product for determining a threshold value (e.g., a threshold cycle number or time value) in a nucleic acid amplification reaction tangibly embodies instructions readable by a machine to perform the steps of deriving a growth curve from measurements of a signal whose intensity is related to a quantity of nucleic acid sequence being amplified in the reaction, calculating a derivative of the growth curve, identifying a characteristic of the derivative, and determining a threshold value associated with the characteristic of the derivative. The method provides for highly reproducible threshold values that are independent of noise or background signal in the amplification reaction. Embodiments of a computer program product for determining a starting quantity of a nucleic acid sequence in a test sample are also provided.
    Type: Application
    Filed: March 14, 2001
    Publication date: March 21, 2002
    Applicant: Cepheid
    Inventors: William A. McMillan, Lee A. Christel, David A. Borkholder, Steven J. Young
  • Publication number: 20020031768
    Abstract: A method for determining an unknown starting quantity of a target nucleic acid sequence in a test sample comprises the steps of amplifying the unknown starting quantity of the target nucleic acid sequence in the test sample and known starting quantities of a calibration nucleic acid sequence in respective calibration samples; and determining a respective threshold value for each of the nucleic acid sequences using a derivative of a growth curve derived for the sequence. The starting quantity of the target nucleic acid sequence in the test sample is determined using the threshold value determined for the target sequence and a calibration curve derived from the threshold values determined for the known starting quantities of the calibration nucleic acid sequences. The invention also provides methods for determining a starting quantity of a nucleic acid sequence in a sample using quantitative internal controls or using internal standards.
    Type: Application
    Filed: March 14, 2001
    Publication date: March 14, 2002
    Applicant: Cepheid
    Inventors: William A. McMillan, Lee A. Christel, David A. Borkholder, Steven J. Young
  • Patent number: 6051422
    Abstract: The invention relates to an apparatus and method for monitoring cells and to a method for monitoring changes in cells upon addition of an analyte to the cell's environment, comprising a device which includes an array of microelectrodes disposed in a cell culture chamber, upon which array a portion of cells adhere to the surfaces of the microelectrodes. The diameter of the cells are larger than the diameters of the microelectrodes. A voltage signal is applied across each of the microelectrodes and a reference electrode. Detection and monitoring of the signals resulting from the application of the voltage signal provides information regarding the electrical characteristics of the individual cells, including impedance (combined cell membrane capacitance and conductance), action potential parameters, cell membrane capacitance, cell membrane conductance, and cell/substrate seal resistance. Such an invention is useful in detecting or screening a variety of biological and chemical agents.
    Type: Grant
    Filed: July 9, 1998
    Date of Patent: April 18, 2000
    Assignee: Board of Trustees, Leland Stanford, Jr., University
    Inventors: Gregory T. A. Kovacs, David A. Borkholder
  • Patent number: 5981268
    Abstract: The invention relates to an apparatus and method for monitoring cells and to a method for monitoring changes in cells upon addition of an analyte to the cell's environment, comprising a device which includes an array of microelectrodes disposed in a cell culture chamber, upon which array a portion of cells adhere to the surfaces of the microelectrodes. The diameter of the cells are larger than the diameters of the microelectrodes. A voltage signal is applied across each of the microelectrodes and a reference electrode. Detection and monitoring of the signals resulting from the application of the voltage signal provides information regarding the electrical characteristics of the individual cells, including impedance (combined cell membrane capacitance and conductance), action potential parameters, cell membrane capacitance, cell membrane conductance, and cell/substrate seal resistance. Such an invention is useful in detecting or screening a variety of biological and chemical agents.
    Type: Grant
    Filed: May 30, 1997
    Date of Patent: November 9, 1999
    Assignee: Board of Trustees, Leland Stanford, Jr. University
    Inventors: Gregory T. A. Kovacs, David A. Borkholder