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Hyoung Woo Park

Publications and source records attributed to Hyoung Woo Park.

11 recordsLinked to original sources
PubMed2006

Efficient cellular uptake of recombinant murine Hoxc8 homeoprotein in COS-7 cells.

In order to analyze the self-delivery activity of Hoxc8, recombinant Hoxc8 protein (rHoxc8) was designed to be expressed and purified in E. coli as a glutathione S-transferase and green fluorescent protein-fused form (GST-GFP-Hoxc8). After purification using glutathione sepharose beads, the 82 kDa fusion protein was separated on the SDS-PAGE gel and confirmed by detecting the fluorescence through luminescent image analyzer. When rHoxc8 was added to culture media for 30 h, most of the COS-7 cells contained the fusion proteins, showing green fluorescence under the fluorescent microscope. When the efficiency of cellular uptake was examined after Hoechst staining, almost 100% of the cells exhibited the GFP signal, revealing that rHoxc8 can traverse the cellular membrane of COS-7 cells efficiently, suggesting that the rHoxc8 could be applied in the development of efficient and useful delivery vectors for therapeutic molecules.

Animals↗
PubMed2005

Membraneous localization of Jpk is not essential to exert cytotoxicity in F9 teratocarcinoma cells.

A novel gene, Jopock (Jpk), which was isolated as a trans-acting factor associating with the PSRE of murine Hoxa-7, has been shown to be toxic to both prokaryotic and eukaryotic cells when overexpressed. Here we demonstrate that the overexpression of enhanced green fluorescent protein (EGFP)-tagged Jpk in F9 cells results in the induction of apoptosis, as indicated by phosphatidylserine exposure, DNA fragmentation, and the alteration of mitochondria transmembrane potential. Fluorescence microscopy showed that EGFP-fused Jpk was mainly localized in the endoplasmic reticulum (ER) and a small amount was found in the mitochondria. Deletion mutants with a transmembrane (TM) domain showed a distribution similar to that of EGFP-Jpk, whereas constructs with a deletion of the TM domain localized in the whole cells. Deletion mapping experiments showed that Jpk with an N-terminal part deleted stimulated apoptosis to almost the same extent as that of the wild-type Jpk, indicating that the localization of Jpk in the ER and the TM domain does not appear to be essential for inducing cytotoxicity. Overall, these results suggest that Jpk, particularly the C-terminal part of Jpk and/or 3'UTR, triggers apoptosis through a perturbation of mitochondrial membrane permeabilization.

Animals↗
PubMed2005

Dynamic expression pattern of Hoxc8 during mouse early embryogenesis.

The Hoxc8 expression pattern was examined in mouse embryos 7.5-12.5 days postcoitum (dpc) using whole-mount in situ hybridization and RT-PCR. The expression of Hoxc8 started between 7.5 and 8.5 dpc. A strong expression was detected in the ectoderm and mesoderm at 8.5 dpc. At 9.5 dpc, a distinct anterior boundary of Hoxc8 expression was established at the 10th and 16th somites in the neural tube and the paraxial mesoderm, respectively. This staggered expression pattern was maintained throughout the later stages. By 12.5 dpc, the forward progression of the Hoxc8 expression pattern was observed and the stain was weakened. In the ectoderm-derived neural tube, strong Hoxc8 expression was observed in the ventral horn and later in the ventral and mediolateral region of the mantle layer, indicating a possible association with the onset and progression of neural differentiation. In the case of the mesoderm-derivative cells, strong Hoxc8 expression was detected in the sclerotome on the way to the notochord and neural tube and mesonephros, suggesting a role of Hoxc8 in the formation of the vertebrae and ribs and the possible involvement in the differentiation into the kidney.

Animals↗
PubMed2004

Cloning of TLR3 isoform.

Toll-like receptor (TLR) 3 is a member of the TLR family that confers innate immunity by recognizing viral pathogens. Herein, we report that the TLR3 isoform is expressed on human primary cells and cell lines. This isoform has 2,520 bp cDNAs compared to the 2,712 bp of full cDNA, is produced by deletion of an intron-like sequence within exon 4 and is co-expressed with wild type TLR3 in primary human astrocytes and glioblastoma cell lines. This finding suggests the TLR3 isoform in astrocytes may have a different immunological role for binding ligands during the immune response in brain.

Astrocytes↗
PubMed2004

Early development of the nose in human embryos: a stereomicroscopic and histologic analysis.

OBJECTIVES/HYPOTHESIS: To analyze the morphologic features of the nose in the human embryo from the 4th to 8th developmental week according to Carnegie stage. STUDY DESIGN: Stereomicroscopic and histologic analysis of the morphology of the human embryo. METHODS: A total of 27 cases of embryos, ranging from Carnegie stage 13 to 23, were analyzed. The external morphology was observed with a stereomicroscope, photographed, and analyzed. The histologic features were observed with a light microscope in the horizontally transected specimens stained with hematoxylin-eosin. RESULTS: The nasal placode was observed in stage 13, and it became flat or even concave in stage 14. In stage 15, the nasal pit was formed. In stage 16, the nasal sac and nasal fin were observed. In stage 17, the oronasal membrane was formed by thinning of the nasal fin. In stage 18, the primitive choana was established by a rupture of the oronasal membrane. In stage 19, the lateral palatine process projected vertically below the level of the tongue. The cartilaginous nasal capsule was formed in stage 20. In stage 21, the olfactory area was localized to the upper portion of the lateral nasal wall and the nasal septum. In stage 22, the lateral palatine process developed in a somewhat horizontal orientation. In stage 23, the premaxilla and primitive choana were formed. CONCLUSIONS: The development of the nose is most active from Carnegie stage 13 to 19, which corresponds to the end of the fourth embryonic week to the end of the seventh week. Thus, this period is considered to be the most important period in human nasal embryonic development.

Embryonic Development↗
PubMed2004

Establishment of stable melanoma cell line expressing a novel gene, jpk, using a tetracycline-controlled gene expression system.

Jpk, originally isolated as an associating factor with the position-specific regulatory element of Hoxa-7, was found to be toxic to Escherichia coli (1) and to F9 teratocarcinoma cells (2) when transiently transfected and expressed. To investigate the possibility of tumor gene therapy using Jpk, its effect was tested in B16F10 murine melanoma cells. Because Jpk reduces the viability of B16F10 cells when transiently expressed, the Jpk gene was cloned into a tetracycline-controlled gene expression vector, pRetro-On to circumvent the lethal effect in unwanted situations. The retroviral plasmid pRetroJpk purified from the packaging cell was infected into B16F10 melanoma cells and screened in the presence of puromycin. Out of a total of 53 stable clones selected with puromycin, two clones overexpressed Jpk at more than twice the level when induced by doxycycline, a tetracycline-derivative, which implies the amount of the Jpk exhibiting the toxicity is critical. Although these clones control only low levels of Jpk, overexpression of the established melanoma cell line may help us decipher the function of Jpk and apply it as a tumor therapeutic gene in the future.

Animals↗
PubMed2003

Timetable for intestinal rotation in staged human embryos and fetuses.

BACKGROUND: The existing data on intestinal rotation during human development are contradictory regarding the timing of major events, and as such an exact timetable for rotation of the intestine in humans is not yet available. METHODS: We studied the initial formation and rotation of the intestine by microdissection and histological observations in 72 human embryos and fetuses at two to 12 weeks postfertilization. The embryos were classified according to the Carnegie staging system. RESULTS: The primordium of the primitive gut was first observed as a yolk sac at stage 5. With the formation of the embryonic foldings, three divisions of the primitive gut (the foregut, midgut, and hindgut) were observed at stage 10. At stage 12, the primitive gut was located on the midline. At stage 15, a 90 degrees counterclockwise rotation of the intestine began. At stage 16, herniation of the intestine into the umbilical cord was not evident in observations of the external form or a transversely sectioned embryo, but was evident in a sagittally sectioned embryo. There was another 90 degrees counterclockwise rotation at stage 20. Reduction of the intestine was a rapid process, since it was still in the cord in fetuses of <40 mm crown-rump length (CRL), and was reduced above 40 mm in general during nine weeks of development. When the intestine returned to the abdominal cavity, the cecum was located in the right lower quadrant (the adult position). CONCLUSIONS: We have developed a standard timetable to describe the rotation of the intestine. The current results will be helpful in studies describing the pathogenesis of some developmental abnormalities in the intestine due to abnormal rotation.

Embryo, Mammalian↗
PubMed2002

Endotoxin-neutralizing antimicrobial proteins of the human placenta.

Microbial colonization and infection of placental tissues often lead to adverse pregnancy outcomes such as preterm birth, a leading cause of neonatal morbidity and mortality. The fetal membranes of the placenta, a physical and active barrier to microbial invasion, encapsulate the fetus and secure its intrauterine environment. To examine the innate defense system of the human placenta, antimicrobial peptides were isolated from the fetal membranes of human placenta and characterized biochemically. Two salt-resistant antimicrobial host proteins were purified to homogeneity using heparin-affinity and reversed-phase HPLC. Characterization of these proteins revealed that they are identical to histones H2A and H2B. Histones H2A and H2B showed dose-dependent inhibition of the endotoxin activity of LPS and inhibited this activity by binding to and therefore blocking both the core and lipid A moieties of LPS. Consistent with a role for histones in the establishment of placental innate defense, histones H2A and H2B were highly expressed in the cytoplasm of syncytiotrophoblasts and amnion cells, where the histone proteins were localized mainly to the epithelial surface. Furthermore, culturing of amnion-derived WISH cells led to the constitutive release of histone H2B, and histones H2A and H2B contribute to bactericidal activity of amniotic fluid. Our studies suggest that histones H2A and H2B may endow the epithelium of the placenta with an antimicrobial and endotoxin-neutralizing barrier against microorganisms that invade this immune-privileged site.

Amino Acid Sequence↗
PubMed2002

A novel factor associating with the upstream regulatory element of murine Hoxa-7 induces bacterial cell death.

In order to understand the function of a cDNA (c171) associated with the upstream regulatory region of the Hoxa-7, the cDNA was cloned into the pGEX-4T-1 vector to produce it as a GST fusion protein. The size of the fusion protein was determined to be 48-kilodalton (kDa). Sequence analysis revealed that a protein C171 contained one hydrophobic transmembrane domain in the N-terminal region and several putative phosphorylation and glycosylation sites. C171 protein inhibited the bacterial growth within 30 min after induction. The transmission electron microscopic examination revealed that the morphology of the cells expressing C171 was changed dramatically: i.e., unusually elongated phenotype compared with those of controls, and finally leading to a cell death. These results altogether indicate that a trace amount of C171 induces bacterial cell death.

Amino Acid Sequence↗
PubMed2002

[A history of medical license in Korea].

Medical license is to qualify a person for medical practice and to attribute him/her a privileged right in the practice. This privileged and exclusive right asks for protection from the side of a state and the state in turn needs qualified medical personnel in order to carry out her task of public health, one of the main duties of modern states. In Europe, physicians succeeded in obtaining medical license that guarantees the privileged right in a highly competitive medical market against other practitioners. The first regulation for medical license in Korea was made in 1900 when few Korean doctors trained in Western medicine was in practice. The regulation aimed at controlling traditional medical practitioners who had been practicing medicine without any qualification as a physician. The regulation was very brief, consisting of only seven articles. A newly revised regulation appeared in 1913 when Korea was under the occupation of Japan. The Japanese Government-General enacted a series of regulations about medical personnel, including dentists and traditional medical practitioners. This heralds its full-scale engagement in medical affairs in Korea. Unlike the case of European countries where medical license was obtained after a long struggle with other practitioners, in Korea, medical license was given to doctors too easily from the state. And this experience played a very important role in the formation of identity of Korean doctors.

History, 20th Century↗