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S Y Yang

Publications and source records attributed to S Y Yang.

At least 37 records · Page 2Linked to original sources
PubMed2001

Molecular cloning, modeling, and localization of rat type 10 17beta-hydroxysteroid dehydrogenase.

Rat and mouse complementary DNAs of type 10 17beta-hydroxysteroid dehydrogenase were cloned and sequenced. The mouse cDNA clone's sequence corrected the previously published nucleotide and amino acid sequence of mouse endoplasmic reticulum-associated beta-amyloid-binding protein. A subunit of the rat enzyme consists of 261 amino acid residues with a calculated molecular mass of 27250 Da. Compared with its human counterpart, rat 17betaHSD type 10 shows 88% identity. Mouse 17betaHSD type 10 is composed of 261 amino acid residues with a calculated molecular mass of 27274 Da. There is 95% identity between the two rodent enzymes. A stereostructure model of rat 17betaHSD type 10 was constructed based on its amino acid sequence. Similar to human type 10 17betaHSD, the rodent enzymes also displayed relatively higher 3alphaHSD activity than 17betaHSD activity. Intracellular localization of rat 17betaHSD type 10 has been determined by subcellular fractionation and confocal microscopy studies. The results unequivocally establish that this is a nuclear gene-encoded mitochondrial enzyme, and that this 17betaHSD is not associated with the endoplasmic reticulum. The unique location distinguishes type 10 from other types of 17beta-hydroxysteroid dehydrogenases.

17-Hydroxysteroid Dehydrogenases↗
PubMed2001

Delta 3,5,delta 2,4-dienoyl-CoA isomerase is a multifunctional isomerase. A structural and mechanistic study.

Delta(3,5),Delta(2,4)-Dienoyl-CoA isomerase (DI), an auxiliary enzyme of unsaturated fatty acid beta-oxidation, was purified from rat mitochondria and peroxisomes and subjected to N-terminal sequencing to facilitate a mechanistic study of this enzyme. The mature mitochondrial DI from rat heart was lacking its 34 N-terminal amino acid residues that have the properties of a mitochondrial targeting sequence. The peroxisomal isomerase was identified as a product of the same gene with a truncated and ragged N terminus. Expression of the cDNA coding for the mature mitochondrial DI in Escherichia coli yielded an enzyme preparation that was as active as the native DI. Because the recombinant DI also exhibited Delta(3,5,7),Delta(2,4,6)-trienoyl-CoA isomerase (TI) activity, both isomerases reside on the same protein. Mutations of any of the 3 acidic amino acid residues located at the active site (Modis, Y., Filppula, S. A., Novikov, D. K., Norledge, B., Hiltunen, J. K., and Wierenga, R. K. (1998) Structure 6, 957-970) caused activity losses. In contrast to only a 10-fold decrease in activity upon replacement of Asp(176) by Ala, substitutions of Asp(204) by Asn and of Glu(196) by Gln resulted in 10(5)-fold lower activities. Such activity losses are consistent with the direct involvement of these latter two residues in the proposed proton transfers at carbons 2 and 6 or 8 of the substrates. Probing of the wild-type and mutants forms of the enzyme with 2,5-octadienoyl-CoA as substrate revealed low Delta(2),Delta(3)-enoyl-CoA isomerase and Delta(5),Delta(4)-enoyl-CoA isomerase activities catalyzed by Glu(196) and Asp(204), respectively. Altogether, these data reveal that positional isomerizations of the diene and triene are facilitated by simultaneous proton transfers involving Glu(196) and Asp(204), whereas each residue alone can catalyze, albeit less efficiently, a monoene isomerization.

Acyl Coenzyme A↗
PubMed2001

Chiral studies across the spectrum of polymer science.

This Account describes how stereochemical ideas focused on chirality have been directed widely across polymer science allowing experiments that could not be conducted on small molecules and leading to new insights and new kinds of materials. In one approach, a helical polymer was studied, and it was discovered how the chiral information necessary to choose helical sense is greatly amplified. In another approach, the racemization kinetics of atropisomers were used to characterize the restrictions to motion associated with a polyelectrolyte that forms clusters around hydrophobic groups in water and in an entirely different system, the glassy state formed by polymers.

Journal Article↗
PubMed2001

Effects of cytokine gene therapy on particulate-induced inflammation in the murine air pouch.

Retroviral vectors encoding the human IL-1 antagonist (IL-1Ra) gene and the human tumor necrosis factor soluble receptor (sTNF-R) gene were investigated using an in vivo model of the inflammatory response to orthopedic wear debris. Air pouches established in BALB/c mice were injected with polymethylmethacrylate (PMMA) particles to provoke an inflammatory reaction, and infected with retroviral vectors expressing IL-1Ra, sTNF-R or a LacZ marker gene. Pouch membranes and fluids were harvested after 48 or 72 hours for analyses. Positive PCR reactions for Neo genes were observed specifically in DNA extracted from the membrane of retroviral-infected pouches. ELISA assays revealed the presence of human IL-1 Ra in pouch fluid from DFG-IRAP-Neo transduced mice, but not control animals. Histological evaluation indicated that the IL-1Ra gene transfer was associated with markedly decreased inflammation in the model, with resolution of the edematous phase of the reaction, decreased pouch fluid accumulation, and lowered macrophage influx. The data suggest that the air pouch model represents a useful tool to evaluate gene therapy, and demonstrate that IL-1Ra gene therapy may be an appropriate therapeutic approach to inflammation.

Animals↗
PubMed2001

Validation of DNA-based HLA-A and HLA-B testing of volunteers for a bone marrow registry through parallel testing with serology.

A total of 42,160 individuals were typed for HLA-A and HLA-B by both serology and PCR-based typing. The HLA assignments included all of the known serological equivalents. The majority of the individuals (99.9%) were from U.S. minority population groups. The serologic typing was performed between 1993 and 1997 at the time of recruitment for the National Bone Marrow Program (NMDP) registry. The polymerase chain reaction (PCR)-based typing was carried out in two phases. In phase I, DNA typing was performed by PCR using sequence-specific oligonucleotide probes (PCR-SSOP) or PCR using sequence-specific primers (PCR-SSP) without knowledge of the serologic assignments. Discrepancies were identified between the serologic and DNA assignments in 24% of the volunteers (8% of volunteers differed for only HLA-A assignments, 13% for HLA-B, and 3% for both HLA-A and -B) and a potential explanation was assigned each discrepant serology/DNA pair. In phase II, a random sampling scheme was used to select a statistically significant number of individuals for repeat DNA typing from each of these categories. The categories included antigens missed by serology, nonexpressed (null) alleles, PCR amplification failures, misassignment of antigens and nomenclature issues. Only a single individual was found to carry a null allele. DNA-based testing correctly typed nearly 99% of the donors at HLA-A, more than 98% at HLA-B, and more than 97% at both HLA-A and -B validating this methodology for registry typing.

Bone Marrow Examination↗
PubMed2001

Characterization and localization of human type10 17beta-hydroxysteroid dehydrogenase.

The tissue distribution, subcellular localization, and metabolic functions of human 17beta-hydroxysteroid dehydrogenase type 10/short chain L-3-hydroxyacyl-CoA dehydrogenase have been investigated. Human liver and gonads are abundant in this enzyme, but it is present in only negligible amounts in skeletal muscle. Its N-terminal sequence is a mitochondrial targeting sequence, but is not required for directing this protein to mitochondria. Immunocytochemical studies demonstrate that this protein, which has been referred to as ER-associated amyloid beta-binding protein (ERAB), is not detectable in the ER of normal tissues. We have established that protocols employed to investigate the subcellular distribution of ERAB yield ER fractions rich in mitochondria. Mitochondria-associated membrane fractions believed to be ER fractions were employed in ERAB/Abeta-binding alcohol dehydrogenase studies. The present studies establish that in normal tissues this protein is located in mitochondria. This feature distinguishes it from all known 17beta-hydroxysteroid dehydrogenases, and endows mitochondria with the capability of modulating intracellular levels of the active forms of sex steroids.

17-Hydroxysteroid Dehydrogenases↗
PubMed2001

Expression of PDGF and its receptor as well as their relationship to proliferating activity and apoptosis of meningiomas in human meningiomas.

In this study, we detected the expression of platelet-derived growth factor (PDGF) and its receptor in 61 human meningiomas by immunohistochemistry and in situ hybridisation. The results showed that almost all the 61 meningiomas expressed PDGFBB and PDGF beta receptor and the positive rate of PDGFAA was 49%. Only two meningiomas expressed PDGF alpha receptor. The positive rate and the immunostaining intensity of PDGFBB and PDGF beta receptor were higher in atypical meningiomas than in benign types. There was no significant difference between the different types of benign meningiomas. The expression of PDGFB chain mRNA was coincident with that of PDGFB chain protein. There was no correlation between the expression of PDGFAA and the types or grades of meningiomas. The correlation between overexpression of PDGFBB/R beta and tumour grade provides a useful parameter in evaluating the prognosis of patients with meningiomas. The proliferative activity of meningiomas was evaluated by the proliferating cell nuclear antigen labelling index (PCNA LI). In the 61 meningiomas, the average PCNA LI (%) was 1.8+/-1.3, 1.9+/-1.3, 1.7+/-0.8 and 11.6+/-5.3 (in fibrous, meningothelial, transitional and atypical meningiomas, respectively). Statistic analysis shows that the PCNA LI is higher in atypical meningiomas than that in benign types, and there was no significant difference between the different types of benign meningiomas. The expression of PDGFBB and PDGF beta receptor was significant enhanced in ascending order from low PCNA LI meningiomas to high ones. This result suggested that PDGFBB/R beta autocrine loop may stimulate the growth of meningiomas. In this study, we also detected the cell apoptosis of meningiomas by terminal deoxynucleotidyl transferase mediated dUTP nick end labelling (TUNEL) method. The average apoptosis labelling index (%) was 0.11+/-0.05, 0.08+/-0.04, 0.09+/-0.03 and 0.35+/-0.15 in fibrous, meningothelial, transitional and atypical meningiomas respectively. The apoptosis labelling index was higher in atypical meningiomas than that in benign types. There was a positive correlation between the apoptosis labelling index and PC NA LI of meningioma. When the positive rate of PDGFBB and/or PDGF beta receptor was higher in meningioma, the apoptotic cells was also increased. In conclusion, the overexpression of PDGFBB and its relevant receptor PDGFR beta in meningiomas was correlated with grade of meningiomas and the proliferative activity of meningiomas; PDGFBB/R beta autocrine loop may play an critical role in the pathogenesis of meningiomas.

Adult↗
PubMed2001

Decreased production of interleukin-12 and interferon-gamma is associated with renal involvement in systemic lupus erythematosus.

OBJECTIVE: To analyze the type 1/type 2 cytokine balance in patients with systemic lupus erythematosus (SLE) according to the presence of renal disorder and activity status. METHODS: We measured the serum levels of type 1 (IFN-gamma, IL-12) and type 2 cytokines (IL-4, IL-10) as well as spontaneous and stimulated cytokine production from peripheral blood mononuclear cells (PBMC) in 40 patients with SLE. RESULTS: Patients with lupus nephritis (LN) showed significantly lower levels of serum IL-12 and IFN-gamma than those without LN. Production of IL-12 and IFN-gamma by stimulated PBMC were also decreased in patients with LN. The circulating IL-12 correlated positively with IFN-gamma, but inversely with IL-10. The SLEDAI scores correlated well with the ratio of IL-4/IFN-gamma levels. CONCLUSION: The reduced production of IL-12 and IFN-gamma and the resultant shift towards the type 2 cytokine phenotype may be associated with LN.

Adolescent↗
PubMed2001

Oriental double eyelid: a limited-incision technique.

Although there are many procedures reported in the literature regarding the double-eyelid operation, they can be categorized basically into two groups: nonincision and incision. Conventionally, the nonincision technique has been shown to produce little postoperative edema. However, the probability of the fold disappearing is high, and this technique cannot be performed in patients with fatty eyelids. Conversely, the incision technique has contrary characteristics. As an alternative option, the author developed a limited-incision single-stitch technique that minimizes tissue injury and provides adequate adhesion for fold formation. With this method, a small single incision (3-4 mm) is made in the upper eyelid. Through the incision, the orbital fat can be removed, when indicated. Under direct vision, a levator aponeurosis or tarsus is attached to the muscle and the dermis of the pretarsal margin by a single stitch. This technique gives a durable, natural fold; has a short recovery time; and can be applied to patients with fatty eyelids. This method has the merits of both the incision and the nonincision techniques, and avoids the disadvantages of both procedures.

Adolescent↗
PubMed2001

Effects of activity on growth factor expression.

For some time, it has been appreciated that muscle mass is regulated locally as well as systemically. We have cloned the cDNA of two isoforms of IGF-1, which are derived from the IGF-1 gene by alternate splicing. The expression of one of these was only detectable after mechanical stimulation. For this reason, this has been called mechano growth factor (MGF). The MGF is not glycosylated, is smaller, and has a shorter half-life in the unbound state than the systemic liver type IGF-1. As the result of a reading frame shift the MGF peptide also has a different C terminal sequence and thus has different binding protein/receptor affinities. Another splice variant (muscle L.IGF-I) is expressed in muscle during rest but is also upregulated by exercise. The latter is similar to the systemic liver type IGF-1. The evidence suggests that MGF has a high potency for inducing local protein synthesis and preventing apoptosis and therefore has an important role in local tissue repair and remodeling. Our physiological experiments show that stretch and particularly stretch combined with electrical stimulation, rather than stimulation alone are important in inducing MGF expression. The mechanotransduction mechanism is believed to involve the muscle cytoskeleton. During aging, the production of growth hormone and IGF-1 by the liver declines markedly. The discovery of MGF and muscle IGF-1 provides a link between physical activity and gene expression. This underlines the need for the elderly to remain active as the locally produced growth factors supplement the circulating IGF-1 levels.

Adaptation, Physiological↗
PubMed2001

Prenatal diagnosis of der(11)t(11;18)(q24;q21.3) due to paternal balanced translocation and both parents are carriers of alpha-thalassemia-1--a case report.

A couple were identified as alpha-thalassemia-1 carriers (father: alpha-thal-1 of Filipino type, mother: alpha-thal-1 of SEA type). Amniocentesis was done at 19 weeks of gestation by a local obstetrician. Molecular study of amniotic fluid presented a non-thalassemia fetus, but the cytogenetic study revealed a karyotype of 46,XX,der(11)t(11;18)(q24;q21.3), resulting from a paternal balanced reciprocal translocation and unbalanced adjacent 1 segregation. The pregnancy was terminated at 23 weeks of gestation. The gross of fetus revealed bilateral cleft lip and palate, hypertelorism, flat nasal bridge, frontal bossing, micrognathia, low set ears, short neck with cystic hygroma, overlapping fingers, prominent heels, and limited hip abduction. The chromosome complement of the present case was partial monosomy for 11q24-qter and partial trisomy for 18q21.3-qter. This is the first prenatal diagnosis of unbalanced translocation with der(11)t(11;18)(q24;q21.3) pat due to paternal balanced translocation and both parents being carriers of alpha-thalassemia-1.

Adult↗
PubMed2001

[Study of diphacinone in biological samples by high performance liquid chromatography/diode array detector].

An analytical approach has been developed for high performance liquid chromatographic determination of diphacinone extracted from liver, blood, urine and kidney of rabbit by solid phase extraction (SPE) cartridges (using SAX, CN or SILICA GEL) with coumarin as the internal standard. Diphacinone was separated by reversed-phase gradient chromatography with DAD detection at 286 nm. The Analytical column was Hypersil BDS C18(150 mm x 4.6 mm i.d., 5 microns) and the guard column was Phenomenex ODS(4 mm x 3.0 mm i.d.). The mobile phase was a gradient mixture of aqueous solution (A) and methanol solution (B) both containing 0.5% ion pair A. There was a good linear relationship between the concentration of diphacinone and the ratio of peak areas of diphacinone and coumarin (internal standard) (r = 0.9999). The linear range was 1 mg/L-100 mg/L, and the lower detection limit was 5 ng (S/N = 3). The average recoveries of diphacinone in urine, blood and liver were 88.4% (n = 3, RSD = 1.25%, SPE by CN column), 82.2% (n = 3, RSD = 1.67%, SPE by SAX column), 91.0% (n = 3, RSD = 2.77%, SPE by SILICA GEL column), respectively.

Animals↗
PubMed2000

Androgen-receptor gene CAG repeats, plasma testosterone levels, and risk of hepatitis B-related hepatocellular carcinoma.

BACKGROUND: Worldwide, hepatocellular carcinoma (HCC) is more prevalent in men than in women, suggesting that sex hormones and/or X-chromosome-linked genes may be involved in hepatocarcinogenesis. We investigated the association of a trinucleotide (CAG) repeat in the androgen receptor (AR) gene (located on the X chromosome) termed "AR-CAG repeats," levels of plasma testosterone, and the risk of HCC in Taiwanese men. Chronic hepatitis B virus (HBV) infection, which is associated with risk of HCC, is hyperendemic in Taiwan. METHODS: We compared the number of AR-CAG repeats in 285 HBV carriers with HCC and in 349 HBV carriers without HCC. We also conducted a nested case--control study on participants in a cohort study. Blood was collected prospectively from 110 case patients and 239 control subjects and was used to determine the number of AR-CAG repeats and plasma testosterone level. All statistical tests were two-sided. RESULTS: The overall odds ratio (OR) for HCC was 1.72 (95% confidence interval [CI] = 1.03--2.89) for HBV carriers with 20 or fewer AR-CAG repeats compared with those with more than 24 repeats. This association was observed only in patients with late-onset HCC (OR = 2.37; 95% CI = 1.28--4.38). In the nested case-control study, HBV carriers in the highest tertile of testosterone levels had a statistically significantly increased risk of HCC (OR = 2.06; 95% CI = 1.14--3.70) compared with those in the lowest tertile. Elevated testosterone was more strongly associated with early-onset (OR = 4.67; 95% CI = 1.41--15.38) than late-onset disease. HBV carriers with 20 or fewer AR-CAG repeats and higher testosterone levels had a fourfold increase in HCC risk compared with those with more than 24 repeats and testosterone levels in the lowest tertile. CONCLUSIONS: Higher levels of androgen signaling, reflected by higher testosterone levels and 20 or fewer AR-CAG repeats, may be associated with an increased risk of HBV-related HCC in men.

Adenine↗
PubMed2000

Cloning and characterization of a new member of the T-box gene family.

The T-box is a strongly conserved protein domain, 174 to 186 amino acids in length, that binds DNA. Many genes from many species have been shown to encode T-box domain-containing proteins. Here we report the cloning and characterization of a novel T-box gene, TBX21. The human cDNA contains an open reading frame encoding a 535-amino-acid protein with a predicted molecular mass of 58.3 kDa. Except for the T-box sequence, database searches revealed no significant homology to any known sequences at the nucleotide or protein level. In addition to the human cDNA sequence, we report the cDNA sequence of the murine homologue, the structure and organization of the murine Tbx21 gene, and its localization to mouse chromosome 11. TBX21 expression was detected in peripheral blood lymphocytes, spleen, lung, and natural killer cells.

Amino Acid Sequence↗
PubMed2000

Genetic polymorphisms of p53 and GSTP1,but not NAT2,are associated with susceptibility to squamous-cell carcinoma of the esophagus.

The interaction of genetic and environmental factors can determine an individual's susceptibility to various cancers. We present a hospital-based case-control study, which included 90 patients of esophageal squamous-cell carcinoma (ESCC) and 254 healthy people in Taiwan, to investigate the effects of genetic polymorphisms of p53, GSTP1 and NAT2 on the risk of ESCC. Polymorphisms of p53, NAT2 and GSTP1 were determined by PCR-RFLP. The codon 72 p53 Pro allele was more frequently found in ESCC patients [odds ratio (OR) 1.86, 95% confidence interval (CI) 1.04-3.35 for Arg/Pro genotype and OR 2.56, 95% CI 1.29-5.08 for Pro/Pro genotype]. In cigarette smokers, the frequency of GSTP1 Ile/Ile genotype was higher in ESCC patients (OR 2.8, 95% CI 1.4-5.7). Among alcohol drinkers, borderline significance was also found for GSTP1 Ile/Ile genotype (OR 2.0, 95% CI 0.9-4.4). Results were not similar for the NAT2 genetic polymorphism. Using logistic analyses, we found that individuals with p53 Pro/Pro genotype had a significantly higher risk of developing ESCC than those with Arg/Arg genotype (OR 2.3, 95% CI 1. 1-5.1), after adjusting for other significant environmental risk factors. This result remained similar (OR 2.2, 95% CI 1.0-4.8 for p53 Pro/Pro vs. Arg/Arg), even after further adjustment for NAT2 and GSTP1 polymorphisms. The codon 72 p53 Pro/Pro genotype in the general population and GSTP1 Ile/Ile in cigarette smokers may predict a higher risk of developing ESCC.

Adult↗
PubMed2000

Detection of beta-amyloid peptide aggregation using DNA electrophoresis.

DNA could readily associate with the aggregated forms of the beta-amyloid peptides beta(1-40) and beta(25-35), giving rise to a shift in the electrophoretic mobility of DNA. As a result, DNA was retained at the top of a 1% agarose gel. In contrast, the electrophoretic mobility of DNA was little influenced by the monomeric forms of beta(1-40) and beta(25-30). DNA from different sources such as lambda phage, Escherichia coli plasmid, and human gene showed similar results. However, the electrophoretic mobility of RNA was shifted by the monomeric beta(1-40) and beta(25-35) as well as by the aggregated beta(1-40) and beta(25-35). The association of DNA with the aggregated beta-amyloid peptides could occur at pH 4-9. The inhibitory action of hemin on beta-amyloid aggregation could be confirmed using the DNA mobility shift assay. These results indicate that the DNA mobility shift assay is useful for kinetic study of beta-amyloid aggregation as well as for testing of agents that might modulate beta-amyloid aggregation.

Amyloid beta-Peptides↗
PubMed2000

Identification of Ankrd2, a novel skeletal muscle gene coding for a stretch-responsive ankyrin-repeat protein.

Mechanically induced hypertrophy of skeletal muscles involves shifts in gene expression leading to increases in the synthesis of specific proteins. Full characterization of the regulation of muscle hypertrophy is a prerequisite for the development of novel therapies aimed at treating muscle wasting (atrophy) in human aging and disease. Using suppression subtractive hybridization, cDNAs corresponding to mRNAs that increase in relative abundance in response to mechanical stretch of mouse skeletal muscles in vivo were identified. A novel 1100-bp transcript was detected exclusively in skeletal muscle. This exhibited a fourfold increase in expression after 7 days of stretch. The transcript had an open reading frame of 328 amino acids encoding an ATP/GTP binding domain, a nuclear localization signal, two PEST protein-destabilization motifs, and a 132-amino-acid ankyrin-repeat region. We have named this gene ankyrin-repeat domain 2 (stretch-responsive muscle) (Ankrd2). We hypothesize that Ankrd2 plays an important role in skeletal muscle hypertrophy.

Amino Acid Motifs↗