Patents by Inventor James Leushner

James Leushner 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).

  • Publication number: 20030082535
    Abstract: Evaluation of a sample for the presence and qualitative nature of a microorganism can be performed in a single vessel by combining a natural abundance DNA sample with a sequencing mixture containing a primer pair, a thermally stable polymerase such as ThermoSequenase™ which incorporates dideoxynucleotides into an extending nucleic acid polymer at a rate which is no less than about 0.4 times the rate of incorporation of deoxynucleotides, nucleotide triphosphate feedstocks, and a chain terminating nucleotide triphosphate. The mixture is processed through multiple thermal cycles for annealing, extension and denaturation to produce a product mixture which is analyzed by electrophoresis.
    Type: Application
    Filed: March 7, 2001
    Publication date: May 1, 2003
    Inventors: James Leushner, May Hui, James M. Dunn, Jean-Michel Lacroix
  • Publication number: 20030022190
    Abstract: Samples are tested for mutations in the BRCA1 gene using a hierarchical approach. First, each sample is amplified in one or more multiplex PCR amplification reactions. Each multiplex PCR reaction produces a mixture of amplified fragments. The sizes and amounts of these fragments are evaluated and compared to standard values reflecting the sizes and amounts of fragments produced when the same multiplex amplification is performed on the wild-type BRCA1 gene. Differences between the observed fragment sizes and/or amounts and those for the wild-type gene are indicative of a mutation with the BRCA1 gene of the sample. Next, one or more of the exons of the BRCA1 gene are sequenced, preferably only for those samples where no mutation was detected by analysis of the multiplex PCR fragments. The sequencing procedure can be performed by amplification and sequencing of the multiplex amplification mixture.
    Type: Application
    Filed: December 26, 2001
    Publication date: January 30, 2003
    Inventors: Robert Shipman, James Leushner, James M. Dunn
  • Patent number: 6413718
    Abstract: Sequencing of a selected region of a target nucleic acid polymer in a natural abundance DNA sample can be performed in a single vessel by combining the sample with a sequencing mixture containing a primer pair, a thermally stable polymerase such as Thermo Sequenase™ which incorporates dideoxynucleotides into an extending nucleic acid polymer at a rate which is no less than about 0.4 times the rate of incorporation of deoxynucleotides, nucleotide feedstocks, and a chain terminating nucleotide. The reaction mixture also includes an unconventional nucleotide and an appropriate enzyme for degradation of nucleic acid polymers containing the unconventional nucleotide. The mixture is processed through multiple thermal cycles for annealing, extension and denaturation to produce a product mixture which is analyzed by electrophoresis.
    Type: Grant
    Filed: April 24, 1998
    Date of Patent: July 2, 2002
    Assignee: Visible Genetics Inc.
    Inventors: James Leushner, Jean-Michel Lacroix, May Hui, James M. Dunn, Marina T. Larson
  • Patent number: 6403303
    Abstract: Samples are tested for mutations in the BRCA1 gene using a hierarchical approach. First, each sample is amplified in one or more multiplex PCR amplification reactions. Each multiplex PCR reaction produces a mixture of amplified fragments. The sizes and amounts of these fragments are evaluated and compared to standard values reflecting the sizes and amounts of fragments produced when the same multiplex amplification is performed on the wild-type BRCA1 gene. Differences between the observed fragment sizes and/or amounts and those for the wild-type gene are indicative of a mutation with the BRCA1 gene of the sample. Next, one or more of the exons of the BRCA1 gene are sequenced, preferably only for those samples where no mutation was detected by analysis of the multiplex PCR fragments. The sequencing procedure can be performed by amplification and sequencing of the multiplex amplification mixture.
    Type: Grant
    Filed: May 14, 1996
    Date of Patent: June 11, 2002
    Assignee: Visible Genetics Inc.
    Inventors: Robert Shipman, James Leushner, James M. Dunn
  • Publication number: 20020037502
    Abstract: Sequencing of a selected region of a target nucleic acid polymer in a natural abundance DNA sample can be performed in a single vessel by combining the sample with a sequencing mixture containing a primer pair, a thermally stable polymerase such as Thermo Sequenase™ which incorporates dideoxynucleotides into an extending nucleic acid polymer at a rate which is no less than about 0.4 times the rate of incorporation of deoxynucleotides, nucleotide feedstocks, and a chain terminating nucleotide. The reaction mixture also includes an unconventional nucleotide and an appropriate enzyme for degradation of nucleic acid polymers containing the unconventional nucleotide. The mixture is processed through multiple thermal cycles for annealing extension and denaturation to produce a product mixture which is analyzed by electrophoresis.
    Type: Application
    Filed: April 24, 1998
    Publication date: March 28, 2002
    Inventors: JAMES LEUSHNER, JEAN-MICHEL LACROIX, MAY HUI, JAMES M. DUNN, MARINA T. LARSON
  • Patent number: 6274315
    Abstract: Sequencing of a selected region of a target nucleic acid polymer in a natural abundance DNA sample can be performed in a single vessel by combining the sample with a sequencing mixture containing a primer pair, a thermally stable polymerase such as Thermo Sequenase™ which incorporates dideoxynucleotides into an extending nucleic acid polymer at a rate which is no less than about 0.4 times the rate of incorporation of deoxynucleotides, nucleotide feedstocks, and a chain terminating nucleotide. The reaction mixture also includes an unconventional nucleotide and an appropriate enzyme for degradation of nucleic acid polymers containing the unconventional nucleotide. The mixture is processed through multiple thermal cycles for annealing, extension and denaturation to produce a product mixture which is analyzed by electrophoresis.
    Type: Grant
    Filed: April 24, 1998
    Date of Patent: August 14, 2001
    Assignee: Visible Genetics Inc.
    Inventors: James Leushner, Jean-Michel Lacroix, May Hui, James M. Dunn, Marina T. Larson
  • Patent number: 6214555
    Abstract: Evaluation of a sample for the presence and qualitative nature of a microorganism can be performed in a single vessel by combining a natural abundance DNA sample with a sequencing mixture containing a primer pair, a thermally stable polymerase such as ThermoSequenase™ which incorporates dideoxynucleotides into an extending nucleic acid polymer at a rate which is no less than about 0.4 times the rate of incorporation of deoxynucleotides, nucleotide triphosphate feedstocks, and a chain terminating nucleotide triphosphate. The mixture is processed through multiple thermal cycles for annealing, extension and denaturation to produce a product mixture which is analyzed by electrophoresis.
    Type: Grant
    Filed: May 13, 1999
    Date of Patent: April 10, 2001
    Assignee: Visible Genetics Inc.
    Inventors: James Leushner, May Hui, James M. Dunn, Jean-Michel LaCroix
  • Patent number: 6083699
    Abstract: A method is provided for simultaneously determining the positions of a selected nucleotide base in a target region of both strands of a denatured duplex nucleic acid polymer. The nucleic acid polymer is combined with a reactant mixture comprising first and second oligonucleotide primers, said primers binding to the sense and antisense strands, respectively, of the nucleic acid polymer at a location flanking the target region; a thermostable DNA polymerase; a chain-terminating nucleotide triphosphate complementary to the selected nucleotide base; and other reagents for synthesis of chain extension products to form a reaction mixture. This mixture is processed through a plurality of thermal cycles, each including at least a chain extension phase and a denaturation phase to produce chain extension products. These chain extension products are evaluated to determine the positions of the selected bases.
    Type: Grant
    Filed: January 20, 1998
    Date of Patent: July 4, 2000
    Assignee: Visible Genetics Inc.
    Inventors: James Leushner, May Hui, James M. Dunn, Marina T. Larson, Jean-Michel Lacroix, Robert Shipman
  • Patent number: 5910413
    Abstract: Amplification primer and sequencing primer sites have been identified which permit sequence-based typing of each of the classical HLA genes in highly robust and consistent reactions without allelic dropout. To determine the DNA sequence, and thus the type of at least one exon of an HLA-A, HLA-B and HLA-C gene present in a sample, the sample is combined with an amplification reaction mixture containing the amplification primers and amplified to form an amplification product including exon 2 and exon 3 of the gene together in a single fragment. The amplification product is then combined with a sequencing reaction mixture containing one or more oligonucleotide sequencing primers which hybridize to a conserved regions the amplification product. The oligonucleotide sequencing primers between them are effective to produce sequencing fragments from all known alleles of exon 2 or exon 3 of the gene under suitable conditions to produce sequencing fragments.
    Type: Grant
    Filed: October 10, 1997
    Date of Patent: June 8, 1999
    Assignee: Visible Genetics, Inc.
    Inventors: Caroline Elizabeth Garey, James Leushner
  • Patent number: 5897842
    Abstract: An apparatus and method for thermally cycling a reaction mixture in a reaction vessel to expose the mixture to the varying temperatures necessary to, for example, achieve PCR amplification or the preparation of sequencing fragments using a cycle sequencing operation makes use of flow-through reaction vessels, such as capillary tubes, for the preparation and thermal cycling of reaction mixtures. In order to prevent loss of the reaction mixture from the vessels during heating, the thermal cycling apparatus of the invention provides means for sealing the proximal and distal end of each reaction vessel. The proximal ends can be sealed by coupling to a pump which permits movement of the samples within the reaction vessels.
    Type: Grant
    Filed: August 27, 1996
    Date of Patent: April 27, 1999
    Assignee: Visible Genetics Inc.
    Inventors: James M. Dunn, James Leushner, John Renfrew, Paul Waterhouse, Alexandre M. Izmailov, Henryk Zaleski
  • Patent number: 5888736
    Abstract: Evaluation of a sample for the presence and qualitative nature of a microorganism can be performed in a single vessel by combining a natural abundance DNA sample with a sequencing mixture containing a primer pair, a thermally stable polymerase such as ThermoSequenase.TM. which incorporates dideoxynucleotides into an extending nucleic acid polymer at a rate which is no less than about 0.4 times the rate of incorporation of deoxynucleotides, nucleotide triphosphate feedstocks, and a chain terminating nucleotide triphosphate. The mixture is processed through multiple thermal cycles for annealing, extension and denaturation to produce a product mixture which is analyzed by electrophoresis.
    Type: Grant
    Filed: February 27, 1997
    Date of Patent: March 30, 1999
    Assignee: Visible Genetics, Inc.
    Inventors: Jean-Michel Lacroix, James Leushner, May Hui, James M. Dunn, Marina T. Larson
  • Patent number: 5834189
    Abstract: The allelic type of a polymorphic genetic locus in a sample is identified by first combining the sample with a sequencing reaction mixture containing a polymerase, nucleotide feedstocks, one type of chain terminating nucleotide and a sequencing primer to form a plurality of oligonucleotide fragments of differing lengths, and then evaluating the length of the oligonucleotide fragments. As in a standard sequencing procedure, the lengths of the fragments indicate the positions of the type of base corresponding to the chain terminating nucleotide in the extended primer. Instead of performing and evaluating four concurrent reactions, one for each type of chain terminating nucleotide, however, the sample is concurrently combined with at most three, and preferably only one, sequencing reaction mixtures containing different types of chain terminating nucleotides. The information obtained from this test is evaluated prior to performing any additional tests on the sample.
    Type: Grant
    Filed: December 22, 1995
    Date of Patent: November 10, 1998
    Assignee: Visible Genetics Inc.
    Inventors: John K. Stevens, James M. Dunn, James Leushner, Ronald J. Green
  • Patent number: 5830657
    Abstract: Sequencing of a selected region of a target nucleic acid polymer in a genomic DNA sample can be performed in a single vessel by combining the sample with a sequencing mixture containing a primer pair, a thermally stable polymerase such as Thermo Sequenase.TM. which incorporates dideoxynucleotides into an extending nucleic acid polymer at a rate which is no less than about 0.4 times the rate of incorporation of deoxynucleotides, nucleotide feedstocks, and a chain terminating nucleotide. The mixture is processed through multiple thermal cycles for annealing, extension and denaturation to produce a product mixture which is analyzed by electrophoresis.
    Type: Grant
    Filed: July 19, 1996
    Date of Patent: November 3, 1998
    Assignee: Visible Genetics Inc.
    Inventors: James Leushner, May Hui, James M. Dunn, Marina T. Larson
  • Patent number: 5789168
    Abstract: Amplification and sequencing of a selected region of a target nucleic acid polymer are be performed in a single vessel. The sample is added to an amplification mixture containing a thermally stable polymerase and nucleoside feedstocks. Chain terminating dideoxynucleosides are added either at the beginning of the amplification reaction or during the course of the amplification. A thermally stable polymerase which incorporates dideoxynucleotides into an extending oligonucleotide at a rate which is no less than about 0.4 times the rate of incorporation of deoxynucleosides can be used in the amplification mixture or added with the chain terminating nucleoside.
    Type: Grant
    Filed: May 1, 1996
    Date of Patent: August 4, 1998
    Assignee: Visible Genetics Inc.
    Inventors: James Leushner, May Hui, James M. Dunn, Marina T. Larson