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Biomedical subjects

W T Hsieh

Publications and source records attributed to W T Hsieh.

At least 19 recordsLinked to original sources
PubMed1999

Correction of chromosomal point mutations in human cells with bifunctional oligonucleotides.

A sequence-specific genomic delivery system for the correction of chromosomal mutations was designed by incorporating two different binding domains into a single-stranded oligonucleotide. A repair domain (RD) contained the native sequence of the target region. A third strand-forming domain (TFD) was designed to form a triplex by Hoogsteen interactions. The design was based upon the premise that the RD will rapidly form a heteroduplex that is anchored synergistically by the TFD. Deoxyoligonucleotides were designed to form triplexes in the human adenosine deaminase (ADA) and p53 genes adjacent to known point mutations. Transfection of ADA-deficient human lymphocytes corrected the mutant sequence in 1-2% of cells. Neither the RD or TFD individually corrected the mutation. Transfection of p53 mutant human glioblastoma cells corrected the mutation and induced apoptosis in 7.5% of cells.

Adenosine Deaminase↗
PubMed1998

Effects of aspirin on arylamine N-acetyltransferase activity in Klebsiella pneumoniae.

This study was designed to assess the effects of aspirin on arylamine N-acetyltransferase (NAT) activities in the bacterium Klebsiella pneumoniae using high performance liquid chromatography to measure the acetylation of 2-aminofluorene (2-AF) with or without aspirin. Cytosols or suspensions of K. pneumoniae with or without specific concentrations of aspirin co-treatment showed different percentages of 2-AF acetylation. The data indicated that there was decreased NAT activity associated with increased levels of aspirin in K. pneumoniae cytosols and in intact bacteria. For the cytosol examination, the apparent values of Km and Vmax decreased 0.59- and 0.58-fold after co-treated with 40 microM aspirin, respectively, for 2-AF. For the intact bacteria examination, the apparent values of Km and Vmax decreased 0.60- and 0.67-fold after co-treated with 40 microM aspirin, respectively, for 2-AF. This report is the first demonstration to show that aspirin can decrease N-acetyltransferase activity in the bacterium K. pneumoniae.

Acetylation↗
PubMed1997

A linkage study of bipolar illness.

BACKGROUND: Although genetic epidemiological studies of bipolar (BP) illness are consistent with a heritable component, inherited risk factors remain unknown. The goal of the present study is to describe the localization of BP susceptibility loci through linkage strategies, including a genome-wide search. METHODS: A linkage study of 22 BP families has been performed. These BP families include almost 400 persons, 173 of whom have been diagnosed as having BP I, schizoaffective, BP II with major depression, or recurrent unipolar illness. Using an autosomal dominant disease model with 85% or 50% age-dependent penetrance, and a recessive model with 85% penetrance, linkage analyses were performed assuming a narrow (BP and schizoaffective) or a broad (BP, schizoaffective, or unipolar) definition of the BP spectrum. Affected sibling pairs and affected pedigree member analyses were performed when positive lod scores were observed in multiple pedigrees. The present article describes linkage analysis of 310 DNA markers on chromosomes 1, 5p, 6, 8, 10q, 11q, and 12 to 18. RESULTS: None of the loci examined disclosed compelling evidence for linkage using lod score analyses. Model-independent analysis by multilocus affected pedigree member method in the pericentromeric chromosome 18 region disclosed statistically significant evidence (P < .0001) for a BP susceptibility gene in this region. Multilocus analysis by affected sibling pair method also disclosed evidence for linkage (P < .00008). CONCLUSIONS: Our results imply that a BP susceptibility gene exists near the centromere of chromosome 18. Confirmation of this finding (by independent investigators studying different pedigrees) has been published, suggesting that a valid BP disease linkage may have been discovered.

Bipolar Disorder↗
PubMed1995

Real-time detection of DNA hybridization and melting on oligonucleotide arrays by using optical wave guides.

The challenge of the Human Genome Project is to increase the rate of DNA sequence acquisition by two orders of magnitude to complete sequencing of the human genome by the year 2000. The present work describes a rapid detection method using a two-dimensional optical wave guide that allows measurement of real-time binding or melting of a light-scattering label on a DNA array. A particulate label on the target DNA acts as a light-scattering source when illuminated by the evanescent wave of the wave guide and only the label bound to the surface generates a signal. Imaging/visual examination of the scattered light permits interrogation of the entire array simultaneously. Hybridization specificity is equivalent to that obtained with a conventional system using autoradiography. Wave guide melting curves are consistent with those obtained in the liquid phase and single-base discrimination is facile. Dilution experiments showed an apparent lower limit of detection at 0.4 nM oligonucleotide. This performance is comparable to the best currently known fluorescence-based systems. In addition, wave guide detection allows manipulation of hybridization stringency during detection and thereby reduces DNA chip complexity. It is anticipated that this methodology will provide a powerful tool for diagnostic applications that require rapid cost-effective detection of variations from known sequences.

Base Sequence↗
PubMed1995

Genetic mapping of adrenergic receptor genes in humans.

We have genetically mapped the genes encoding four human adrenergic receptors (ARs) of subtypes alpha 1C, alpha 2A, alpha 2B, and beta 1, which are prototypic G protein coupled receptors that mediate the physiological effects of neurotransmitters, hormones, and drugs. We placed these genes onto the Cooperative Human Linkage Center (CHLC) and Genethon framework maps, within confidence intervals with greater than 1000:1 odds. With multipoint analysis the alpha 1C gene (locus ADRA1C) mapped to the interval between NEFL and D8S283; alpha 2-C4, the gene encoding the alpha 2C AR (locus ADRA2C), mapped to the interval between D4S126 and D4S62; and the alpha 2-C10 (alpha 2A AR)/beta 1 haplotype (loci ADRA2A/ADRB1) mapped to the interval between D10S259 and D10S187. A fifth AR gene, beta 2, yielded significant LOD scores with markers on the long arm of chromosome 5; however, this locus (ADRB2) could not be mapped to any specific interval with odds of greater than 1000:1. The two AR genes that are completely linked, alpha 2-C10 and beta 1, were oriented on their shared 225-kb genomic fragment relative to the direction of transcription, with beta 1 being 5' to alpha 2-C10. The positioning of these genes on high-density framework maps allows them to be tested as candidates in a spectrum of diseases that might involve AR dysfunction.

Base Sequence↗
PubMed1994

Genetic linkage mapping for a susceptibility locus to bipolar illness: chromosomes 2, 3, 4, 7, 9, 10p, 11p, 22, and Xpter.

We are conducting a genome search for a predisposing locus to bipolar (manic-depressive) illness by genotyping 21 moderate-sized pedigrees. We report linkage data derived from screening marker loci on chromosomes 2, 3, 4, 7, 9, 10p, 11p, 22, and the pseudoautosomal region at Xpter. To analyze for linkage, two-point marker to illness lod scores were calculated under a dominant model with either 85% or 50% maximum penetrance and a recessive model with 85% maximum penetrance, and two affection status models. Under the dominant high penetrance model the cumulative lod scores in the pedigree series were less than -2 at theta = 0.01 in 134 of 142 loci examined, indicating that if the disease is genetically homogeneous linkage could be excluded in these marker regions. Similar results were obtained using the other genetic models. Heterogeneity analysis was conducted when indicated, but no evidence for linkage was found. In the course of mapping we found a positive total lod score greater than +3 at the D7S78 locus at theta = 0.01 under a dominant, 50% penetrance model. The lod scores for additional markers within the D7S78 region failed to support the initial finding, implying that this was a spurious positive. Analysis with affected pedigree member method for COL1A2 and D7S78 showed no significance for linkage but for PLANH1, at the weighting functions f(p) = 1 and f(p) = 1/sqrt(p) borderline P values of 0.036 and 0.047 were obtained. We also detected new polymorphisms at the mineralocorticoid receptor (MLR) and calmodulin II (CALMII) genes. These genes were genetically mapped and under affection status model 2 and a dominant, high penetrance mode of transmission the lod scores of < -2 at theta = 0.01 were found.

Bipolar Disorder↗
PubMed1992

Confirmation of the human cathepsin B gene (CTSB) assignment to chromosome 8.

Human cathepsin B gene (CTSB) has been mapped to two locations: 8p22 and 13q14. Here we confirm the chromosome 8 assignment by three independent methods: (1) analysis of human-hamster somatic cell hybrid DNA by polymerase chain reaction; (2) comparison of hybridization signals to cathepsin B in interphase nuclei of normal fibroblasts and fibroblasts with a chromosome 8 deletion; and (3) fluorescence in situ hybridization to metaphase spreads using cathepsin B cosmid clones. Our results indicate that human CTSB is located at 8p22-p23.1.

Base Sequence↗
PubMed1992

A systematic search for a bipolar predisposing locus on chromosome 5.

Chromosome 5 markers spanning the pter to the qter were used to examine linkage to bipolar illness in 14 pedigrees. Twenty-four loci were examined in 237 individuals, of whom 69 were either bipolars or schizoaffectives. Marker genotypes were determined for each individual and lod scores were calculated under a dominant disease model with a maximum penetrance of 85%, a disease gene frequency of 0.015, a variable age of onset, and a phenocopy rate of 0.001. Under the assumption that bipolar illness is genetically homogeneous, the total lod scores from all pedigrees with each marker were uniformly lower than -2.0, suggesting the absence of linkage to disease at any of these loci. Multipoint analysis allowed exclusion of intervals between markers. When lod scores were calculated allowing for heterogeneity, no subset of linked families was found. These results indicate that in our pedigree series almost the entire mapped region of chromosome 5 can be excluded for linkage to bipolar illness.

Bipolar Disorder↗
PubMed1991

The human kininogen gene (KNG) mapped to chromosome 3q26-qter by analysis of somatic cell hybrids using the polymerase chain reaction.

Kinins, peptide products of kininogens, may be involved in hypertensive and diabetic diseases, and inflammatory disorders. The human kininogen gene (KNG) has been mapped to chromosome 3, using a panel of human-hamster somatic cell hybrids by polymerase chain reaction of hybrid DNA with gene-specific primers. KNG was further assigned to 3q26-3qter, using DNA from a second panel of chromosome 3 deletion mapping cell hybrids.

Animals↗
PubMed1991

Mapping of the gene for human cysteine proteinase inhibitor stefin A, STF1, to chromosome 3cen-q21.

The gene for the human cysteine proteinase inhibitor stefin A (STF1), alias cystatin A, has been mapped to chromosome 3, using the polymerase chain reaction to specifically amplify the human stefin A sequence in human-hamster hybrid DNA. STF1 is further sublocalized to regions between centromere and 3q21 using a deletion mapping panel for this chromosome. This assignment shows that stefin A is not syntenic with cystatin C which has been localized to chromosome 20.

Animals↗
PubMed1991

Gene mapping of human cathepsins and cystatins.

Chromosomal locations of human cathepsin B, stefin A and kininogen have been determined. Using techniques of somatic cell hybrids and polymerase chain reaction, cathepsin B has been mapped to 8p22, stefin A to 3cen-q21, and kininogen to 3q26-qter. Comparing this data with currently available mapping loci, it can be concluded that many members of cathepsins are dispersed in different chromosomes, whereas members of the cystatin family are restricted to only two human chromosomes, 3 and 20.

Cathepsin B↗
PubMed1991

Genetic and physical mapping of the human cannabinoid receptor gene to chromosome 6q14-q15.

A cDNA encoding a G protein-coupled receptor that appears to mediate the behavioral effects of cannabinoids, the psychoactive ingredients of marijuana, has recently been cloned from rat cerebral cortex and expressed. We have now determined the genomic location of the human cannabinoid receptor gene (CNR) by a combination of genetic linkage mapping and chromosomal in situ hybridization. The segregation pattern of a CNR DNA polymorphism was analyzed in 508 individuals from two or three generations of 40 families. Linkage of CNR to chromosome 6 centromeric loci and to DNA markers on the long and short arms was detected. CNR was tightly linked to D6S27, which is known to be located at 6q (log10 odds ratio [lod score, Zmax] of 10.54 at a recombination fraction [theta] of 0.02). Close linkage was suggested between CNR and CGA, the locus for the alpha subunit of human chorionic gonadotropin (Zmax = 2.71 at theta = 0). Moreover, CNR was linked to the two markers 308/BamHI (theta = 0.14) and 308/TaqI (theta = 0.20) defining locus D6Z1, an extended, highly repetitive, and highly conserved sequence localized exclusively to centromeres of all chromosomes and enriched on chromosome 6. In situ hybridization using a biotinylated cosmid probe localizes the gene to 6q14-q15, thereby confirming the linkage analysis and defining a precise alignment of the genetic and cytogenetic maps.

Cannabinoids↗