Functional evidence for a breast cancer growth suppressor gene on chromosome 17

Rearrangements or deletions of chromosome 17 are the most frequentlyobserved genetic changes identified in breast tumors. Molecularanalyses suggest that in addition to the p53 gene on 17p13.1there may be at least three other tumor suppressor genes onchromosome 17 involved in breast cancer. Regions of loss ofheterozygosity (LOH) identified on 17p13.3 and 17q12-qter occurfrequently in breast tumors, and the BRCA-1 gene has been mappedto 17q21 by genetic linkage analysis. Here we provide biologicalevidence for the presence of a growth suppressor gene(s) onchromosome 17 that results In the In vitro growth suppressionof the p53 wild-type MCF 7 breast cancer cell line. We haveIntroduced a normal chromosome 17 into MCF 7 cells by microcellmediatedchromosome transfer (MMCT), and demonstrate that cells growtharrest before 10 to 12 population doublings. In contrast, theintroduction of a normal chromosome 13 had no effect upon growthof these cells either In vitro or In vivo. These data providedirect functional evidence for the presence of a growth suppressorgene(s) on chromosome 17, which is not p53, and which may representone of several gene(s) that play a critical role in the developmentof breast cancer.     

Compliance with oral theophylline therapy in asthmatic children

Serum theophylline levels were obtained from 111 children on continuous theophylline therapy when seen in the emergency department for acute episodes of wheezing. Sixty-six percent of patients were at least partially compliant and only 34% were noncompliant in medication taking on the basis of a serum theophylline level of less than 5 micrograms/mL. The main factors associated with compliance were type of primary care source, whether the patient had difficulty keeping appointments, and the relationship of the caretaker to the patient.     

Fluorescent microsphere-based readout technology for multiplexed human single nucleotide polymorphism analysis and bacterial identification

Large-scale human genotyping requires technologies with a minimal number of steps, high accuracy, and the ability to automate at a reasonable cost. In this regard, we have developed a rapid, cost-effective readout method for single nucleotide polymorphism (SNP) genotyping that combines an easily automatable single-tube allele-specific primer extension (ASPE) with an efficient high throughput flow cytometric analysis performed on a Luminex 100 flow cytometer. This robust technique employs an ASPE reaction using PCR-derived target DNA containing the SNP and a pair of synthetic complementary capture probes that differ at their 3' end-nucleotide defining the alleles. Each capture probe has been synthesized to contain a unique 25-nucleotide identifying sequence (ZipCode) at its 5' end. An array of fluorescent microspheres, covalently coupled with complementary ZipCode sequences (cZipCodes), was hybridized to biotin-labeled ASPE reaction products, sequestering them for flow cytometric analysis. ASPE offers both an advantage of streamlining the SNP analysis protocol and an ability to perform multiplex SNP analysis on any mixture of allelic variants. All steps of the assay are simple additions of the solutions, incubations, and washes. This technique was used to assay 15 multiplexed SNPs on human chromosome 12 from 96 patients. Comparison of the microsphere-based ASPE assay results to gel-based oligonucleotide ligation assay (OLA) results showed 99.2% agreement in genotype assignments. In addition, the microsphere-based multiplex SNPs assay system was adapted for the identification of bacterial samples by both ASPE and single base chain extension (SBCE) assays. A series of probes designed for different variable sites of bacterial 16S rDNA permitted multiplex analysis and generated species- or genus-specific patterns. Seventeen bacterial species representing a broad range of gram-negative and gram-positive bacteria were analyzed within 16 variable sites of 16S rDNA sequence. The results were consistent with the published sequences and confirmed by direct DNA sequencing.