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K Yoon

Publications and source records attributed to K Yoon.

78 records · Page 5Linked to original sources
PubMed1982

Control of elastin synthesis.

mRNA was isolated from the thoracic aortas of 16-day chick embryos and used to synthesize blunt-ended heteroduplex molecules consisting of one strand of mRNA and one of cDNA using AMV reverse transcriptase and S1 nuclease. The duplexes were tailed with dCTP and hybridized to the plasmid pBR322 which had been restricted with Pst I and tailed with dGTP. Recombinant plasmids were used to transform E. coli C600 and colonies containing elastin cDNA were selected by in situ hybridization with 32P labeled elastin mRNA and by hybrid selected translation using the nuclease-treated reticulocyte lysate system. mRNA recovered from hybridization to DNA of one clone, pWB1, markedly stimulated incorporation of [3H]valine into a protein which was immunoprecipitable with elastin-specific antibody and had a molecular weight of 72,000, characteristic of tropoelastin. The 230 bp insert of pWB1 was sequenced by the technique of Maxam and Gilbert and found to be derived from a nontranslated region of the 3' end of the mRNA. Nick-translated pWB1 was used to identify and to estimate the relative amounts of elastin mRNA in the developing chick embryo aorta by blot hybridization. A single mRNA species of 3.5 kb hybridized to the pWB1 probe and this species increased greatly in amount between day 7 and day 14. This increase was paralleled by an increase in translatable elastin mRNA and by the rate of elastin synthesis of aortas from various age embryos incubated in vivo. The injection of 150 microgram of hydrocortisone 21-phosphate into 8-day eggs produced a significant increase in both the relative rate of tropoelastin synthesized by the isolated aortas and the relative amount of elastin mRNA. These results suggest that the observed changes in elastin synthesis during development and after hydrocortisone administration are governed by the elastin mRNA content of the aortas.

Animals↗
PubMed1976

The kinetics of binding of U-U-C-A to a dodecanucleotide anticodon fragment from yeast tRNA-Phe.

The kinetics of U-U-C-A binding to the dodecanucleotide (A-Cm-U-Gm-A-A-Y-A-psi-m5C-U-Gp) isolated from the anticodon region of yeast tRNA-Phe are similar to the kinetics of binding of U-U-C-A to intact tRNA-Phe. A large enhancement in binding constant over that predicted for U-U-C-A-U-G-A-A is observed for both the complexes of dodecanucleotide and tRNA-Phe with U-U-C-A. This strongly suggests that both the anticodon loop in tRNA-Phe and the dodecanucleotide can form four base pairs with U-U-C-A. Furthermore, the enhanced stability cannot be attributed to a special conformation of the anticodon loop, but instead the anticodon loop is probably flexible. A likely explanation for the increased binding is the effect of non-base-paired ends. This increased thermodynamic stability comes from a larger entropy gain rather than a larger enthalpy decrease.

Adenine Nucleotides↗
PubMedDate not supplied

Targeted gene conversion in a mammalian CD34+-enriched cell population using a chimeric RNA/DNA oligonucleotide.

Gene conversion of genetically inherited point mutations is a fundamental methodology for treating a variety of diseases. We tested the feasibility of a new approach using an RNA/DNA chimeric oligonucleotide. The beta-globin gene was targeted at the point mutation causing sickle cell anemia. The chimera is designed to convert an A residue to a T after creating a mismatched basepair. In a CD34+-enriched population of normal cells a 5-11% conversion rate was measured using restriction enzyme polymorphism and direct DNA sequence analyses. The closely related delta-globin gene sequence appeared unchanged despite successful conversion at the beta-globin locus.

Antigens, CD34↗
PubMedDate not supplied

Intestinal tuberculosis with abdominal complications: radiologic and pathologic features.

BACKGROUND: To investigate radiologic and pathological features of intestinal tuberculosis with abdominal complications. METHODS: Twenty-two patients with 23 surgically proven complications (nine intestinal obstructions, eight perforations, three fistulae, and three intestinal bleeds) were analyzed. Medical records, radiologic studies, and pathologic examinations were reviewed with special emphasis on searching for the common features in each group of complication. RESULTS: The most important single feature in seven of the nine patients with intestinal obstruction was the presence of stricture. In the remaining two patients, bowel adhesion was a primary cause of obstruction. In eight patients with intestinal perforation, both obstruction and ulcerations in the dilated proximal loop were the important features in six, and multiple deep ulcerations without obstruction was a primary cause in the remaining two. The common features in three patients with fistulae were focal or multiple strictures, severe adhesions, and fibrotic bowel wall. Intestinal bleeding originated from diffuse mucosal ulcerations. The abdominal complications occurred during antituberculous therapy in 10 of the 22 patients. CONCLUSION: Understanding the radiologic and pathologic features of intestinal tuberculosis with complications help in making an appropriate clinical decision for the treatment strategy. Close observation is necessary, especially in those patients who are acutely ill during antituberculous medical therapy. Enteritis-Intestines, diseases-Intestines, infection-Intestines, perforation-Intestines, stenosis or obstruction.

Female↗