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Biomedical subjects

Y Kwon

Publications and source records attributed to Y Kwon.

60 records · Page 4Linked to original sources
PubMed1992

Induction of motor neuron sprouting in vivo by ciliary neurotrophic factor and basic fibroblast growth factor.

Ciliary neurotrophic factor (CNTF) and basic fibroblast growth factor (bFGF) were tested for effects on sprouting by motor neurons innervating the adult mouse gluteus muscle. Factors were delivered by subcutaneous injection directly over the surface of the superior gluteus muscle once daily for 7 d and then end plates and axons were visualized by combined silver and cholinesterase staining. CNTF (500 ng daily) induced sprouting both from end plates and from the subset of nodes of Ranvier that are closest to the end plate. The effect of CNTF was potentiated twofold by coadministration of bFGF at doses of 2-20 ng daily, whereas treatment with bFGF alone failed to induce sprouting from either end plates or nodes of Ranvier. The sprouting stimulus delivered by the factors showed limited penetrance into the muscle and restricted lateral spread from the injection site.

Amino Acid Sequence↗
PubMed1992

Korean children's understanding of multidigit addition and subtraction.

This study examined Korean second and third graders' understanding of multidigit addition and subtraction and particularly their ability to explain the trading required when a column sum of the addends is 10 or more. 72 middle-class second- and third-grade children (aged 7-4 to 8-4 and 8-4 to 9-4, respectively, at the time of the midyear interview) attending 2 schools in Seoul, Korea, were asked to solve 2- and 3-digit problems given in vertical form and then were individually interviewed about their conceptual understanding of such problems. Even though the second graders had not yet received instruction in school on 3-digit problems, children in both grades were quite accurate solvers of the multidigit addition and subtraction problems and demonstrated knowledge of the place-value names "ten" and "hundred." Every child also correctly identified the trade between the ones and tens columns as a traded ten. Most of the third graders identified the 1 written in the hundreds column on the addition problems as a hundred, but half of the second graders identified it as a ten. Most of the third graders also gave correct descriptions of the trading (regrouping, borrowing) required by a 3-digit subtraction problem with 2 zeros in the top number. Children used 3 different conceptual structures in discussing the already-solved problems: a multiunit quantities structure, a regular one/ten trades structure, and a combination of these two. These results are compared to the literature on the performance and conceptual structures of children in the United States.

Child↗
PubMed1983

Cold injury-induced swelling of brain and other tissues: its molecular mechanism.

Isolated mouse brain, kidney, and other tissues were incubated for from one to several days at 4 degrees C in isotonic solutions containing varying mixtures of sucrose and NaCl (or Na2SO4, LiCl, Li2SO4, MgSO4). The ischemic, cold-injured tissues swelled in proportion to the concentration of NaCl or LiCl. They swelled less in Na2SO4 and Li2SO4 and they swelled even less and/or shrank in MgSO4 or sucrose. It was shown that in the presence of about 100 mM NaCl, the degree of swelling follows inversely the level of ATP present in the cells. The data were interpreted using the theory of cell swelling based on the association-induction hypothesis: NaCl- and LiCl-induced swelling in injured tissues and KCl-induced swelling in normal tissues, were both explained as the consequence of the dissociation of the volume-restraining effects of salt linkages among cell proteins. The depletion of ATP and the consequent increase of electron density or c-value of the fixed anionic groups turns NaCl (ineffective in causing swelling of normal tissues) into a fully effective agent for causing swelling of the injured tissues.

Adenosine Triphosphate↗