Biomedical subjects

Sang Yong Kim

Publications and source records attributed to Sang Yong Kim.

3 recordsLinked to original sources

PubMed2003

Dicer is essential for mouse development.

To address the biological function of RNA interference (RNAi)-related pathways in mammals, we disrupted the gene Dicer1 in mice. Loss of Dicer1 lead to lethality early in development, with Dicer1-null embryos depleted of stem cells. Coupled with our inability to generate viable Dicer1-null embryonic stem (ES) cells, this suggests a role for Dicer, and, by implication, the RNAi machinery, in maintaining the stem cell population during early mouse development.

Amino Acid Sequence↗

PubMed2003

Isolation of the enhanced neurovirulent HSV-1 strains from Korean patients.

Herpes simplex virus type 1 (HSV-1) is a neurotropic DNA virus which has latency in human. In this study, we isolated various HSV-1 strains, named KHS, from the skin lesions of Korean patients and characterized the specific features of each strain. We found that KHS strains produced small, cell associated and nonsyncycial plaques in Vero cells. We classified KHS strains into two substrains, KHS 1 which had highly condensed plaques and KHS 2 which had less condensed plaques. Since gD protein of HSV-1 plays important roles in viral plaque formation, we determined the nucleotide sequences of gD genes of KHS strains. According to deduced amino acid sequences of gD protein in KHS strains compared with prototype strains KOS and F, we found that gD of KHS strains have more putative O-glycosidic sites, serine in KHS 1 and threonine in KHS 2, respectively. To find out the establishment of viral latency, we infected each virus strain into eyes of mice and carried out trigerminal ganglia explanting experiment. We found that both KHS strains established latent infections stably just as did the prototype KOS and F strains. The eye swab experiments were carried out to check the viral replication in vivo. KHS 1 exhibited a longer shedding time in eyes of mice. We also found that KHS 1 has a higher neurotropic affinity by determining the time it took for the virus to reach the trigerminal ganglia from the eyes. Currently, we are studying the possible mechanism of high neuroinvasiveness of KHS 1 strain.

Animals↗

PubMed2002

Synthesis of cationic polysaccharide derivatives and their hypocholesterolaemic capacity.

High-capacity bile acid-sequestering biopolymers with cationic polysaccharide derivatives have been developed. Cholestyramine, the bile acid sequestrant most widely used for treating hypercholesterolaemia, has unpleasant side effects because of the hydrophobic nature of its backbone. Methylan, a high-viscosity polysaccharide produced by Methylobacterium organophilum, was selected as a model polysaccharide for derivatization. Methylan was aminated to add dialkylaminoalkyl and free amino groups at hydroxyl sites in the methylan backbone, and these derivatives were quaternized to produce pH-independent cationic polyelectrolytes. The in vitro bile acid-binding capacity of quaternized DEAE-methylan was approximately 50% higher than that of cholestyramine. The bile acid-binding capacity of methylan derivatives increased with the number of carbons in the alkyl groups, indicating that hydrophobic interaction is a secondary factor for the sequestration of bile acids.

Anticholesteremic Agents↗