Maximal utilization of the left internal mammary artery for coronary bypass grafting.
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Coronary Artery Bypass↗
Biomedical subjects
H W Yang
Publications and source records attributed to H W Yang.
High-level production of recombinant human lysosomal acid alpha-glucosidase in Chinese hamster ovary cells which targets to heart muscle and corrects glycogen accumulation in fibroblasts from patients with Pompe disease.
Infantile Pompe disease is a fatal genetic muscle disorder caused by a deficiency of acid alpha-glucosidase, a glycogen-degrading lysosomal enzyme. We constructed a plasmid containing a 5'-shortened human acid alpha-glucosidase cDNA driven by the cytomegalovirus promoter, as well as the aminoglycoside phosphotransferase and dihydrofolate reductase genes. Following transfection in dihydrofolate reductase-deficient Chinese hamster ovary cells, selection with Geneticin, and amplification with methotrexate, a cell line producing high levels of the alpha-glucosidase was established. In 48 hr, the cells cultured in Iscove's medium with 5 mM butyrate secreted 110-kDa precursor enzyme that accumulated to 91 micrograms.ml-1 in the medium (activity, > 22.6 mumol.hr-1.ml-1). This enzyme has a pH optimum similar to that of the mature form, but a lower Vmax and Km for 4-methylumbelliferyl-alpha-D-glucoside. It is efficiently taken up by fibroblasts from Pompe patients, restoring normal levels of acid alpha-glucosidase and glycogen. The uptake is blocked by mannose 6-phosphate. Following intravenous injection, high enzyme levels are seen in heart and liver. An efficient production system now exists for recombinant human acid alpha-glucosidase targeted to heart and capable of correcting fibroblasts from patients with Pompe disease.
Animals↗
Genetic clinical markers of human neuroblastoma with special reference to N-myc oncogene: amplified or not amplified?--An overview.
Neuroblastoma is the most common extracranial tumor in children, and cytogenetically, chromosome 1p deletions, extrachromosomal double minutes, and homogeneously staining regions (HSRs) are commonly observed in cell lines and in tumors in advanced stages. It is found that an HSR represents genomic amplification of N-myc, which plays a key role in determining the aggressiveness of neuroblastoma. However, stage IV neuroblastomas or cell lines which lack N-myc amplification are also progressive, and some of them show evidence of N-myc expression in terms of mRNA and/or N-Myc oncoprotein. It was recently shown that a small proximal locus mapped between 1p35-36.1 and 1p36.23 may function as a suppressor gene of N-myc amplification. In neuroblastoma, a pattern of diploidy is associated with rapid tumor growth and poor survival. Expression of bcl-2 proto-oncogene is strongly associated with unfavorable histology, while expressions of Ha-ras and trk-A proto-oncogenes indicate a favorable prognosis. trk-A proto-oncogene encodes a receptor for nerve growth factor. Genetic characteristics of neuroblastomas found by urinary catecholamine mass screening are also discussed.
Biomarkers, Tumor↗
Experimental studies on the application of a porcelain-light-cured resin matrix system to the porcelain margin of metal-ceramic crowns.
Application of a light-cured porcelain margin is a technique which has been developed recently. In this study, we compared the porcelain margin properties of the porcelain-light-cured resin matrix system and the traditional porcelain-water system, in terms of volumetric shrinkage, density, compressive strength, surface characteristics, internal porosity, separability of the condensed porcelain from the stone die, and the marginal integrity. The experimental resin matrix was composed of BDMA or EGDMA as a base monomer, CQ as a photoinitiator, DEAEMA as a polymerization accelerator, and TEGDMA as a diluent. Compared with the conventional system, the porcelain of the resin matrix system tended to show a larger volumetric shrinkage, a smaller density and a lower compressive strength. The experimental groups containing the diluent and the traditional control group demonstrated smoother surfaces and less internal porosity than those without the diluent. The photoinitiator was thought to play an important role on the separability from the stone die and the marginal integrity; the higher the ratio of the photoinitiator (1.0 wt%), the better the separability and the fit.
Compressive Strength↗
[Clinical application of percutaneous transhepatic internal cholangio-drainage].
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Adolescent↗
DNA fragmentation factor 45 (DFF45) gene at 1p36.2 is homozygously deleted and encodes variant transcripts in neuroblastoma cell line.
Recently, loss of heterozygosity (LOH) studies suggest that more than two tumor suppressor genes lie on the short arm of chromosome 1 (1p) in neuroblastoma (NB). To identify candidate tumor suppressor genes in NB, we searched for homozygous deletions in 20 NB cell lines using a high-density STS map spanning chromosome 1p36, a common LOH region in NB. We found that the 45-kDa subunit of the DNA fragmentation factor (DFF45) gene was homozygously deleted in an NB cell line, NB-1. DFF45 is the chaperon of DFF40, and both molecules are necessary for caspase 3 to induce apoptosis. DFF35, a splicing variant of DFF45, is an inhibitor of DFF40. We examined 20 NB cell lines for expression and mutation of DFF45 gene by reverse transcription (RT)-polymerase chain reaction (PCR) and RT-PCR-single-strand conformation polymorphism. Some novel variant transcripts of the DFF45 gene were found in NB cell lines, but not in normal adrenal gland and peripheral blood. These variants may not serve as chaperons of DFF40, but as inhibitors like DFF35, thus disrupting the balance between DFF45 and DFF40. No mutations of the DFF45 gene were found in any NB cell line, suggesting that the DFF45 is not a tumor suppressor gene for NB. However, homozygous deletion of the DFF45 gene in the NB-1 cell line may imply the presence of unknown tumor suppressor genes in this region.
Alternative Splicing↗
A polyclonal antibody against synthetic peptide conserved in N-Myc protein reacts with water-soluble recombinant N-Myc protein.
The importance of determining the N-Myc protein has been emphasized in neuroblastoma. We attempted to obtain a water-soluble N-Myc protein, and an antibody highly specific for the N-Myc protein. A plasmid was constructed from partial exons 2 and 3 of the N-myc gene, and expressed in Escherichia coli by isopropyl-beta,-D-thiogalactopyranoside. Newly obtained N-Myc (rN-Myc) was water-soluble with a M.W. of 38 kDa. An N-Myc-specific peptide, GVAPPRPGG RQTSGGDH, was used to raise an antibody. Specificity of the obtained antibody was confirmed and we found the rN-Myc protein reacts positively with the anti-N-Myc IgG raised here. The rN-Myc protein and the anti-N-Myc IgG obtained are expected to be used in an ELISA for N-Myc.
Amino Acid Sequence↗