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Y S Chang

Publications and source records attributed to Y S Chang.

At least 19 recordsLinked to original sources
PubMed1997

Molecular cloning, structural analysis, and expression of carp ZP2 gene.

The cDNAs encoding carp ZP2 homologous to winter flounder and mammalian ZP2 were cloned. Carp ZP2 contains a tandemly repetitive domain and a nonrepetitive domain. A repeat is composed of 13 amino-acid residues whose consensus sequence is QQTSQQFQPQKPA/V. The length of the repetitive domain is highly variable, but that of the nonrepetitive domain is fairly constant among various cDNAs. The termination codons of various cDNAs appear at three different positions. Three groups of cDNAs were therefore categorized. Groups I-III encode a nonrepetitive domain of 356, 255, and 10 residues, respectively. A carp ZP2 gene corresponding to group II cDNA was cloned. It spans 2.4 kb and consists of eight exons and seven introns. Carp ZP2 mRNA was detected only in oocytes but not in other tissues. Carp ZP2 is heterogenous in size. The molecular weight ranges from 40-80 kDa. It is present in vitellogenic but not in previtellogenic oocytes, nor in other tissues. Carp ZP2 content in oocytes increases as vitellogenesis proceeds.

Amino Acid Sequence↗
PubMed1997

Effect of population density on the early post-implantation mouse embryo growth in vitro.

OBJECTIVES: To investigate the relationship between embryo population density and embryo development in vitro. METHODS: Swiss Webster albino mice were used and blastocysts were flushed from the uterine horns. Various numbers of blastocysts were randomly assigned to separate 35 mm dishes and cultured for 9 days. RESULTS: The effect of duration of culture to the mean success rates was different as the number of embryos in the dish was changed. In early egg cylinder (EEC) stage, the mean success rate was a flat function of the number of embryos. But the mean success rate was a decreasing function in late egg cylinder (LEC) stage and the decreasing rate was faster in early somite (ES) stage. Interestingly, the mean success rate to ES stage was nearly constant when more than 10 embryos were cultured in one dish. CONCLUSION: The success rate to each developmental stage in vitro decreased as the number of embryos in the dish and the duration of cultured increased.

Animals↗
PubMed1997

Evaluation of acute renal failure in bacterial allograft pyelonephritis using abdominal CT and graft biopsy.

The causes of acute renal failure in bacterial allograft pyelonephritis were evaluated using abdominal CT and graft biopsy. Twenty-one recipients, who showed a poor response to antibiotic therapy, comprised this study group. The diagnostic approach taken with this poor responder group was first to perform abdominal CT. If a focal lesion was identified on abdominal CT, a diagnosis of acute focal bacterial nephritis or renal abscess was made. If no focal lesion was found, a graft biopsy was performed for diagnosis. Abdominal CT revealed focal lesions in 9 of the 21 recipients, and renal biopsy showed superimposed acute rejection in 8 of the 12 recipients biopsied. In conclusion, acute renal failure in allograft pyelonephritis is associated with not only severe infection but also a superimposed acute rejection process. Therefore, imaging study and graft biopsy are recommended in the poor responder group.

Acute Kidney Injury↗
PubMed1997

Serum and urine soluble HLA class I antigen concentrations are increased in patients with hemorrhagic fever with renal syndrome.

OBJECTIVES: In order to evaluate the association between the Hantaan virus-induced cellular-immune response and clinical severity in patients with hemorrhagic fever with renal syndrome (HFRS). METHODS: We serially measured the serum (n = 16) and urine (n = 6) concentrations of soluble HLA class 1 antigen (sHLA-l) and clinical powameters in patients with HFRS. RESULTS: Serum sHLA-I concentrations in patients with HFRS were significantly higher than those in controls throughout all clinical phases (p < 0.01). The highly elevated Serum sHLA-I concentrations peaked in the oliguric phase and declined gradually through the phases of HFRS. Serum sHLA-l concentrations in patients with hypotensive episode were higher than in those without the episode (5,85 +/-2,184 vs. 2,389 +/- 860 ng/ml in oliguric phase, 4.11 +/- 1,952 vs. 1,502 +/- 592 ng/ml in diuretic phase, p < 0.05), and serum sHLA-l levels showed a significant correlation with blood WBC count (r = 0.75 in the febrile and hypotensive phase, p < 0.01) and serum creatinine concentrations (r = 0.64 in the oliguric phase, p < 0.01), respectively, Urine sHLA-I levels in the oliguric phase were significantly higher than those in the diuretic phase (390 +/- 155 vs. 214 +/- 45 ng/mg Cr, p < 0.05) and urine sHLA-I levels are associated with severe illness in patients with HFRS. The higher serum sHLA-I are associated with severe illness in patients with HFRS. The persistent elevation of serum sHLA-I during all phases of HFRS might be related to increased production due to prolonged cellular immunologic stimulation by the Hantaan virus rather than decreased excretion of sHLA-I through the kidney. CONCLUSION: We suggest that the serum and urine sHLA-I concentrations can be used as a stable and objective parameter for monitoring clinical severity and renal dysfunction in patients with HFRS.

Adult↗
PubMed1996

Molecular cloning and functional expression of mouse connexin-30,a gap junction gene highly expressed in adult brain and skin.

A new gap junction gene isolated from the mouse genome codes for a connexin protein of 261 amino acids. Because of its theoretical molecular mass of 30.366 kDa, it is named connexin-30. Within the connexin gene family, this protein is most closely related to connexin-26 (77% amino acid sequence identity). The coding region of mouse connexin-30 is uninterrupted by introns and is detected in the mouse genome as a single copy gene that is assigned to mouse chromosome 14 by analysis of mouse x hamster somatic cell hybrids. Abundant amounts of connexin-30 mRNA (two transcripts of 2.0 and 2.3 kilobase pairs) were found after 4 weeks of postnatal development in mouse brain and skin. Microinjection of connexin-30 cRNA into Xenopus oocytes induced formation of functional gap junction channels that gated somewhat asymmetrically in response to transjunctional voltage and at significantly lower voltage (Vo = +38 and -46 mV) than the closely homologous connexin-26 channels (Vo = 89 mV). Heterotypic pairings of connexin-30 with connexin-26 and connexin-32 produced channels with highly asymmetric and rectifying voltage gating, respectively. This suggests that the polarity of voltage gating and the cationic selectivity of connexin-30 are similar to those of its closest homologue, connexin-26.

Amino Acid Sequence↗
PubMed1996

Shear stress-induced release of PGE2 and PGI2 by vascular smooth muscle cells.

This study addresses the direct effect of fluid flow shear stress on production of the vascular mediators, PGE2 and PGI2 by vascular smooth muscle cells (SMC). Results indicate that shear stress increases PGE2 and PGI2 release in SMC. The production patterns, however, differ between PGE2 and PGI2. For PGE2, the rate of production is moderate for the first three hours after the onset of shear stress, then dramatically increases between the fourth and fifth hours, returning to basal levels in the sixth hour. On the other hand, the rate for PGI2 production is maximal right after the onset of shear and remains elevated for the first three hours. The rate then plateaus and remains at a moderate level during the next three hours. The results also indicate that SMC production of PGI2 is more sensitive to shear stress than PGE2 production since a level of 0.5 dynes/cm2 produces a maximal PGI2 release whereas 1 dyne/cm2 produces only 1/4 the response seen at 20 dynes/cm2 for PGE2. The physiological implications of fluid shear stress regulation of SMC are discussed.

6-Ketoprostaglandin F1 alpha↗
PubMed1996

Effect of a 10-amino acid deletion on the oncogenic activity of latent membrane protein 1 of Epstein-Barr virus.

A previous study has shown that the BNLF1 of Epstein-Barr virus (EBV), isolated from a nasopharyngeal carcinoma biopsy (BNLF1-1510), was able to transform Balb/3T3 cells. On the other hand, BNLF1 of a prototype virus B95-8 (BNLF1-958) was not transforming unless the gene was transcribed from a strong promoter. In this study, we have generated chimeric BNLF1 by exchanging the DNA fragments between BNLF1-1510 and BNLF1-958 and examined their expression and transformation ability in Balb/3T3 cells. Results showed that transformation of Balb/3T3 cells by BNLF1-1510 was not due to the excessive expression of the gene. Transfection of Balb/3T3 cells with chimeric BNLF1 showed that the genes with 3' 453 bp sequence of BNLF1-1510 were oncogenic to the cells. Study also revealed that changing the numbers of the 33 bp repeats in the 3' region of the two BNLF1s did not affect the transformation characteristics. On the other hand, deletion of a 30 bp sequence of BNLF1-958, which is absent in BNLF1-1510, changed the gene from non-oncogenic to oncogenic and insertion of this 30 bp sequence into BNLF1-1510 abolished the transformation ability. BNLF1 without this 30 bp sequence was also found in the tumours of other EBV-related neoplastic disease, suggesting that absence of this 30 bp sequence in BNLF1 may be associated with the oncogenesis of these diseases.

3T3 Cells↗
PubMed1996

Characterization of the replicon of plasmid pSW500 of Erwinia stewartii.

A 1.6-kb DNA region required for the replication of pSW500 from Erwinia stewartii SW2 has been identified. DNA sequencing analysis revealed that this DNA fragment consists of a DnaA box, seven 16-bp direct repeats, and a 1005-bp open reading frame. The seven direct repeats have been demonstrated to mediate the incompatibility function of the plasmid. Primer extension analysis showed that the 1005-bp ORF is transcribed in vivo and the +1 site of the transcript is located 113 bp upstream from the translation initiation codon of the ORF. Complementation studies showed that this ORF is required for the replication of the plasmid and may encode a replication protein, RepA. Gene fusion studies revealed that the expression of repA is autoregulated by RepA. We also found that the pSW500 replicon has a copy number of approximately two and that the plasmid is stably maintained in Escherichia coli, thus demonstrating that the replicon contains all the elements required for copy number control and plasmid stability in E. coli. Curing of pSW500 from E. stewartii SW2 revealed that loss of pSW500 did not have any obvious effect on morphology or physiology of the cells, suggesting that pSW500 does not encode a function that is indispensable for the survival of the organism.

Amino Acid Sequence↗
PubMed1996

Bone remodeling around implanted ceramics.

Bone formation and remodeling around implanted materials is influenced by the kind of material, its surface properties, and the anatomical site of implantation. In this study, differences in bone formation around three kinds of ceramics and the importance of the implant location in the tibia were investigated. In the first experiment, we placed three kinds of ceramics--alumina, zirconia and hydroxyapatite (HA)--into the medullary cavity of rabbit tibiae and examined histologically the time-dependent formation of bone around the materials for up to 24 weeks postoperatively. We found that bone formation depends on whether or not the materials are in direct contact with the endosteum. In the second experiment, the same three ceramic materials were implanted transcortically into rabbit tibiae. The bone formed around the implants was most abundant in regions adjacent to the periosteum, followed by the endosteum and the marrow cavity in the approximate ratios of 70%, 40%, and 10%, respectively. In these two experiments, the difference between bioactive and bioinert ceramics could be seen in the interface between the implanted material and the bone. It can be concluded that bone formation around these materials is related to the osteoconductivity of the materials and to the osteogenic capacity of the tissues.

Aluminum Oxide↗
PubMed1996

Molecular cloning, structural analysis, and expression of carp ZP3 gene.

Two types of cDNAs coding for a major component of carp egg membrane were clones from a carp ovarian cDNA library. They encode polypeptides of 422-424 amino acid residues whose sequences are homologous to those of medaka and mammalian ZP3. Similar to the mammalian ZP3 genes, carp ZP3 gene also consists of eight exons and seven introns. Carp ZP3 genes are 2.9 kb in length and present in multiple forms. Carp ZP3 is a glycoprotein of 45 kDa. It was transcribed and translated exclusively in oocytes, in contrast with medaka ZP3, which was synthesized in liver. The transcription of carp ZP3 starts very early in oogenesis, but translation occurs during vitellogenesis, as it is present in vitellogenic but not in previtellogenic oocytes. ZP3 content in oocytes increases as vitellogenesis proceeds.

Amino Acid Sequence↗
PubMed1996

Simultaneous program of natural-cycle in vitro fertilization and cryopreserved-thawed embryo transfer.

PURPOSE: This clinical study was designed to identify and compare the pregnancy rates of simultaneous program of natural-cycle IVF and cryopreserved-thawed ET (NICE) with those of natural-cycle IVF and cryopreserved-thawed ET. METHODS: All three groups comprised spontaneously ovulating infertile women under the age of 40 and without any male factor present. The NICE program was performed in 36 patients (47 cycles) who had previously undergone IVF-ET resulting in cryopreserved embryos. As control groups, the natural-cycle IVF was performed in 45 patients (80 cycles), and the cryopreserved-thawed ET alone in 29 patients (40 cycles). RESULTS: The cancellation rate of the initiated cycles prior to ET was 19.1% (9/47) in the NICE group, 23.8% (19/80) in the natural-cycle IVF group, and 2.5% (1/40) in the cryopreserved-thawed ET group. The mean number of embryos transferred was 4.0 +/- 1.1 (2-5) in the NICE group, 1.0 in the natural-cycle IVF group, and 4.2 +/- 1.8 (1-5) in the cryopreserved-thawed ET group. The clinical pregnancy rates per aspiration cycle (32.5%) and per ET cycle (34.2%) in the NICE group were significantly higher than those (14.9, 16.4%) in the natural-cycle IVF group. The clinical and delivered pregnancy rates per ET (34.2, 26.3%) in the NICE group were higher than those (20.5, 15.4%) in the cryopreserved-thawed ET group, without statistical significance. CONCLUSIONS: Since the NICE program results in saving the fresh oocyte for patients participating in cryopreserved-thawed ET, more favorable pregnancy rates may be obtained from NICE cycles in women ovulating normally who had previously undergone IVF-ET with embryo cryopreservation.

Adult↗
PubMed1996

Significance of interstitial bone ingrowth under load-bearing conditions: a comparison between solid and porous implant materials.

Interstitial bone ingrowth is extremely important for optimum fixation of implanted materials under load-bearing conditions. In this study, three types of biomaterial test piece were manufactured in solid and open-pore structures, and implanted into dog femoral condyles. Bone formation and remodelling were observed histologically and roentgenologically for 24 weeks thereafter. The study demonstrated that, 24 weeks after implantation, thick fibrous tissue surrounded by corticalized bone formed around both solid smooth-surfaced alumina and titanium implants. On the other hand, however, with an implant made of an artificial osteochondral composite material, thickening of ingrown trabeculae could be observed as early as 4 weeks. Bone ingrowth into the titanium fibre mesh was ambundant and increased with time after implantation. This interstitial bone ingrowth resulted in the complete integration of this implant and the viable host bone. Our findings suggest that interstitial bone ingrowth has great significance, even though new bone formation and remodelling follows Wolff's law after the completion of the bonding between the bone and implanted material under load-bearing conditions. The artificial osteochondral composite material could lead to complete integration of the implant and viable bone, suggesting that it is a promising material for joint replacements. Moreover, the tibial joint surface which bore against the polyvinyl alcohol hydrogel surface of this implant remained intact, which suggests that this composite is a very promising biomaterial for use in joint prostheses.

Animals↗
PubMed1996

Molecular cloning and nucleotide sequence determination of three envelope genes of classical swine fever virus Taiwan isolate p97.

A strain of classical swine fever virus (CSFV) has been isolated in Taiwan. The cDNA coding for three envelope glycoproteins E1, E2 and E3 were molecularly cloned from purified viral particles using the reverse transcription-polymerase chain reaction (RT-PCR) method and sequence-specific primers. The resulting PCR products (1113 bp for E1. 699 bp for E2 and 567 bp for E3) were cloned into the SmaI site of pUC19 and then subjected to DNA sequence analysis. Data showed that nucleotide sequence of the three envelope genes shared a 82-83% homology with the corresponding genes of three other strains (Alfort, Brescia and Weybridge). However, the homology of the deduced amino acid sequence was greater than 90% among the four strains. The potential asparagine-linked glycosylation sites for E1 (5 sites), E2 (7 sites) and E3 (2 sites) were conserved. This suggests that the Taiwan p97 strain is distinct from other three strains described. The variations may have implications for future vaccine development. The sequence has been submitted to GenBank. The accession numbers are U43924 and U03290.

Amino Acid Sequence↗
PubMed1996

Purification and molecular cloning of carp ovarian cystatin.

The ovarian fluid of carp consists of many components. Using the antiserum against carp serum, Western blot analysis of ovarian fluid was done in order to distinguish substances synthesized by the ovary from those derived from the serum. Several ovary-specific substances were detected including a protein of 12 kDa (p12), which was purified to homogeneity. Purified p12 displays a single band in SDS-PAGE under nonreducing condition and it can inhibit the enzymatic activity of papain with an apparent inhibition constant of 0.01 nM. The primary structure of p12 was partially determined by Edman degradation and fully elucidated by molecular cloning. A cDNA of 531 bp encoding p12 was obtained. The precursor of p12 has 129 residues, including a signal peptide of 18 residues and a mature protein of 111 residues. The N- and C-terminus of p12 are threonine and methionine, respectively. The p12 shares many common features of the family 2 cystatins of other species, including the similarity of the protein size (in the range of 110 to 120 residues), the presence of 4 cysteine residues and the occurrence of invariant residues throughout the molecule.

Amino Acid Sequence↗
PubMed1996

Effects of Gastrodia elata and its active constituents on scopolamine-induced amnesia in rats.

The effects of the rhizome of Gastrodia elata Blume (Orchidaceae) (abbreviated as GE) and its active constituents on learning and memory by using the one-trial passive avoidance task were studied in rats. At the 1.0 g/kg dose administered for one week, the methanol extract of GE significantly prolonged the shortened step-through latency induced by scopolamine in the passive avoidance task. Furthermore, at the 50.0 mg/kg dose administered for one week, the ethyl acetate and n-butanol fractions of the methanol extract prolonged the shortened step-through latency induced by scopolamine in rats. Gastrodin, isolated from the n-butanol fraction of the methanol extract, and p-hydroxybenzyl alcohol, isolated from the ethyl acetate fraction of the methanol extract, also significantly prolonged the shortened step-through latency induced by scopolamine on the passive avoidance task. These results suggested that gastrodin and p-hydroxybenzyl alcohol may be the active constituents of GE.

Amnesia↗
PubMed1996

Current status of assisted reproductive technology in Asia and Oceania.

OBJECTIVE: To summarize the procedures and outcomes of assisted reproductive technology (ART) initiated in Asia-Oceanic region in 1992 and 1993. DESIGN: Data were collected on an annual summary form and submitted to the Reproductive Biology Committee of AOFOG. PARTICIPANTS: Twelve member countries of AOFOG submitted data on ART procedures performed in 1992 and 1993-Australia, Egypt, Hong Kong, India, Indonesia, Japan, Korea, New Zealand, Pakistan, Singapore, Taiwan, and Thailand. Data were collected in 1995 so that the outcomes of all pregnancies established would be known. MAIN OUTCOME MEASURES: Clinical characteristics of patients, causes of infertility, protocols and outcomes of controlled ovarian hyperstimulation (COH), and outcomes of clinical pregnancy including abortion, ectopic pregnancy, multiple pregnancy, and congenital malformation were measured in each ART procedure. RESULTS: In 1992, 23,872 cycles of IVF-ET were performed with 21.8% clinical pregnancy rate (PR) per ET, 4,840 cycles of GIFT with 29.5% PR per transfer, 1,136 cycles of simultaneous IVF-ET and GIFT with 29.9% PR, and 1,563 cycles of ZIFT with 23.1% PR. Total 575 clinical pregnancies were achieved in cryopreserved ET program, 96 pregnancies in oocyte donation program, and 87 pregnancies in microassisted fertilization (MAF) program. In 1993, 24,571 cycles of IVF-ET were performed with 21.6% clinical PR per ET, 5,240 cycles of GIFT with 28.2% PR per transfer, 1,063 cycles of simultaneous IVF-ET and GIFT with 32.0% PR, 1,005 cycles of ZIFT with 21.6% PR, 5,562 cycles of cryopreserved ET program with 12.8% PR, and 2,198 cycles of MAF program with 11.6% PR. Total 117 clinical pregnancies were achieved in oocyte donation program. CONCLUSIONS: Although the concepts as well as the status and results of ART are continuously changing, this report may be helpful in planning the future of ART in Asia-Oceania by analyzing the past history.

Asia↗
PubMed1996

Effect of exogenous glycine on peptidoglycan composition and resistance in a methicillin-resistant Staphylococcus aureus strain.

A highly homogeneously methicillin-resistant Staphylococcus aureus strain was grown in the presence of various concentrations of exogenous glycine. Increasing concentrations of glycine in the medium resulted in a decrease in methicillin resistance and the appearance of a heterogeneous resistance phenotype. Parallel to the gradual changes in resistance was an alteration in the muropeptide composition of peptidoglycan. Increasing concentrations of glycine in the medium resulted in peptidoglycan in which muropeptides with a D-alanyl-D-alanine terminus were replaced with D-alanyl-glycine-terminating muropeptides. The disappearance of D-alanyl-D-alanine-terminating muropeptides in peptidoglycan and the concomitant decrease in resistance indicate a central role for D-alanyl-D-alanine-terminating precursors in methicillin resistance.

Amino Acid Sequence↗