Abstract: Methods for identifying stem cells and other cells specific to embryogenesis and carcinogenesis, classifying tissue samples, diagnosing precancerous and cancerous or atherosclerotic lesions, testing the value of anticancer agents, discovering macromolecules specifically expressed in particular cell types, using stem cells in restorative tissue therapy as well as methods for preparing tissue samples so heteromorphic nuclear morphotypes remain intact are disclosed.

Abstract: The invention relates to a method for identifying inherited point mutations in a targeted region of the genome in a large population of individuals and determining which inherited point mutations are deleterious, harmful or beneficial. Deleterious mutations are identified directly by a method of recognition using the set of point mutations observed in a large population of juveniles. Harmful mutations are identified by comparison of the set of point mutation observed in a large set of juveniles and a large set of aged individuals of the same population. Beneficial mutations are similarly identified.

Abstract: Methods for detecting low frequency nuclear mutations in a target sequence from a genomic DNA sequence are disclosed.

Abstract: The invention relates to a method for identifying inherited point mutations in a targeted region of the genome in a large population of individuals and determining which inherited point mutations are deleterious, harmful or beneficial. Deleterious mutation are identified directly by a method of recognition using the set of point mutations observed in a large population of juveniles. Harmful mutations are identified by comparison of the set of point mutation observed in a large set of juveniles and a large set of aged individuals of the same population. Beneficial mutations are similarly identified.

Abstract: The invention relates to a method for identifying inherited point mutations in a targeted region of the genome in a large population of individuals and determining which inherited point mutations are deleterious, harmful or beneficial. Deleterious mutations are identified directly by a method of recognition using the set of point mutations observed in a large population of juveniles. Harmful mutations are identified by comparison of the set of point mutation observed in a large set of juveniles and a large set of aged individuals of the same population. Beneficial mutations are similarly identified.

Abstract: The present invention pertains to a line of human blood cells which have high levels of oxidative activity (such as oxygenase, oxidase, peroxidase, and hydroxylase activity). Such cells grow in suspension culture, and are useful to determine the mutagenicity of xenobiotic substances that are metabolized into toxic or mutagenic substances. The invention also includes mutation assays using these cells, and other cells with similar characteristics.

Abstract: The disclosure relates to a method for resolving double-stranded DNA species differing by at least one base pair. Each of the species is characterized by an iso-melting domain with a unique melting temperature contiguous with a melting domain of higher thermal stability.

Abstract: A method of resolving (physically separating) mutant DNA from nonmutant DNA and a method of defining or establishing a mutational spectrum or profile of alterations present in nucleic acid sequences from a sample to be analyzed, such as a tissue or body fluid. The present method is based on the fact that it is possible, through the use of DGGE, to separate nucleic acid sequences which differ by only a single base change and on the ability to detect the separate mutant molecules.The present invention, in another aspect, relates to a method for determining a mutational spectrum in a DNA sequence of interest present in a population of cells.

Abstract: A line of human blood cells which have high levels of oxidative activity (such as oxygenase, oxidase, peroxidase, and hydroxylase activity) is disclosed. Such cells grow in suspension culture, and are useful to determine the mutagenicity of xenobiotic substances that are metabolized into toxic or mutagenic substances. Mutation assays using these cells, and other cells with similar characteristics, are also disclosed.

Abstract: An assay is disclosed for determining mutagenic damage caused by the administration of a known or suspected mutagen to diploid human lymphoblastoid cell lines. The gene locus employed for this assay is the gene for thymidine kinase, uridine kinase, or cytidine deaminase. Since human lymphoblastoid cells contain two genes for these enzymes, heterozygotes of human lymphoblastoid cells are used in this assay.

Abstract: An assay is disclosed for determining mutagenic damage caused by the administration of a known or suspected mutagen to bacterial cells such as Salmonella typhimurium. After administration of or exposure to a mutagenic agent, the bacterial cells are plated in the presence of a purine analog and resistance to purine analogs is used as the genetic marker. This bioassay system can be used by genetic toxicologists to determine the potential genetic hazards from the use of a variety of suspected or known mutagens, including newly-developed chemicals.

Abstract: Improved cell culture microcarriers, and methods for their production and use, are disclosed herein. These improved microcarriers have positive charge capacities adjusted and/or controlled within a range suitable for good cell growth. One method for producing such improved microcarriers is by treating beads formed from polymers containing pendant hydroxy groups, such as dextran beads, with an aqueous solution of an alkaline material and a chloro- or bromo-substituted tertiary amine under precisely controlled conditions to produce the desired exchange capacity. The resultant positively charged microcarriers have been used in microcarrier cultures to produce outstanding growth of anchorage-dependent cells. Such cells can be harvested, or used for the production of viruses, vaccines, hormones, interferon or other cellular growth by-products.

Abstract: Improved cell culture microcarriers, and methods for their production and use, are disclosed herein. These improved microcarriers have positive charge capacities adjusted and/or controlled within a range suitable for good cell growth. One method for producing such improved microcarriers is by treating beads formed from polymers containing pendant hydroxy groups, such as dextran beads, with an aqueous solution of an alkaline material and a chloro- or bromo-substituted tertiary amine under precisely controlled conditions to produce the desired exchange capacity. The resultant positively charged microcarriers have been used in microcarrier cultures to produce outstanding growth of anchorage-dependent cells. Such cells can be harvested, or used for the production of viruses, vaccines, hormones, interferon or other cellular growth by-products.

Abstract: An assay is disclosed for determining mutagenic damage caused by the administration of a known or suspected mutagen to diploid human lymphoblastoid cell lines. After administration of or exposure to a mutagenic agent, the lymphoblasts are incubated for a sufficient number of generations to allow full expression of phenotypic resistance to 6-thioguanine or other purines which serve as substrates for hypoxanthine guanine phosphoribosyl transferase (HGPRT). A surprising discovery is the remarkably long length of time required for such phenotypic expression. After the phenotypic lag has passed, the mutant fraction can be determined to complete the assay. A nontoxic, active, sterile microsomal drug-metabolizing system compatible with mammalian cell bioassays is also disclosed which can be used in the assay to determine metabolite-caused mutagenesis.

Abstract: A method of treating certain cell culture microcarriers to improve their performance is disclosed. In this method, positively charged microcarriers, such as those produced by reacting polydextran beads with diethylaminoethyl, are treated by contacting them with macromolecular polyanions, such as carboxymethylcellulose, prior and/or during use in cultures. Such treatment overcomes deleterious effects previously observed in attempts to use these microcarriers in cell culture systems.