Biomedical subjects

Sung Kyu Park

Publications and source records attributed to Sung Kyu Park.

5 recordsLinked to original sources

PubMed2006

The flavonoid ellagic acid from a medicinal herb inhibits host immune tolerance induced by the hepatitis B virus-e antigen.

The aim of this study is to characterize the role of ellagic acid, a flavonoid from a medicinal herb which blocks HBeAg secretion in a HBV infected cell line and in HBeAg transgenic mice, in immune tolerance in chronic HBV infection. Using the mouse strain C57ML/6, HBeAg-producing transgenic mice (HBeAg-Tg), under the control of metal ion-inducible promoter were generated. The effect on immune tolerance of HBeAg-Tg and the release of immune tolerance by the inhibitor of HBeAg secretion, ellagic acid, was tested using T/B cell proliferation, HBeAg/HBeAb production, cytotoxic T-lymphocyte (CTL) and cytokine assays. C57ML/6 based HBeAg-producing HBeAg-Tg mice were tolerant to HBeAg at the T and B-cell level, did not produce antibodies to HBeAg in vivo and in vitro, produced minimal levels of cytokines (IL-4 and IFN-gamma) and decreased CTL responses, while feeding mice with ellagic acid (5mg/kg body weight) blocked the immune tolerance caused by HBeAg. Our results suggest that host immune tolerance induced by HBeAg during HBV infection, a viral strategy to guarantee HBV infection, can be overcome by ellagic acid, thus it can be used as a therapeutic for HBV-carriers.

Animals↗

PubMed2006

Central limit theorem as an approximation for intensity-based scoring function.

In this paper, we present an intensity-based probability function to identify peptides from tandem mass spectra and amino acid sequence databases. The function is an approximation to the central limiting theorem, and it explicitly depends on the cumulative product ion intensities, number of product ions of a peptide, and expectation value of the cumulative intensity. We compare the results of database searches using the new scoring function and scoring functions from earlier algorithms, which implement hypergeometric probability, Poisson's model, and cross-correlation scores. For a standard protein mixture (tandem mass spectra generated from the mixture of five known proteins), we generate receiver operating curves with all scoring schemes. The receiver operating curves show that the shared peaks count-based probability methods (like Poisson and hypergeometric models) are the most specific for matching high-quality tandem mass spectra. The intensity-based (central limit model) and intensity-modeled (cross-correlation) methods are more sensitive when matching low-quality tandem mass spectra, where the number of shared peaks is insufficient to correctly identify a peptide. Cross-correlation methods show a small advantage over the intensity-based probability method.

Algorithms↗

PubMed2005

Extensive brain stem lesions in thrombotic thrombocytopenic purpura: repeat magnetic resonance findings.

The authors report on an unusual case of extensive brain stem lesions as a manifestation of thrombotic thrombocytopenic purpura (TTP). A 28-year-old woman developed rapidly progressive neurologic deficits 5 days after a cesarean delivery. Her condition had been normal after delivery. Initial magnetic resonance imaging (MRI) revealed extensive T2 hyperintense lesions involving the entire brain stem; only part of the pons showed hyperintense abnormalities in a concomitantly taken diffusion-weighted image. The hematologic evaluations and her clinical course revealed the diagnosis of TTP, so plasma exchange and methyl-prednisolone therapy were initiated. After 10 days of treatment, she developed neurologic improvement. A follow-up MRI on the 75th day revealed dramatically reduced brain stem lesions with only residual punctate lesions in the pons. Her remaining neurologic deficits were dysarthria, limb ataxia, and left hemiparesis. As demonstrated in this study, extensive brain stem involvement should be added as a possible neuroimaging feature of TTP.

Adult↗

PubMed2003

Comparison of lenograstim and filgrastim on haematological effects after autologous peripheral blood stem cell transplantation with high-dose chemotherapy.

OBJECTIVE: To compare the efficacy of lenograstim and filgrastim on haematological recovery following an autologous peripheral blood stem cell transplantation (PBSCT) with high-dose chemotherapy. METHODS: A retrospective case-controlled study. RESULTS: Absolute neutrophil count (ANC) recovery above 0.5 x 10(9)/l and white blood cell (WBC) recovery above 4 x 10(9)/l for 3 consecutive days was achieved earlier with filgrastim than with lenograstim ((13.2 +/- 8.0 vs 19.0 +/- 10.0 days, p = 0.004), (16.9 +/- 9.7 vs 29.9 +/- 16.6 days, p = 0.001), respectively). The platelet recovery above 20 x 10(9)/l was also achieved earlier with filgrastim than with lenograstim (19.5 +/- 11.6 vs 27.2 +/- 13.8 days, p = 0.006). Furthermore, filgrastim-treated patients received fewer days of granulocyte colony simulating factor (G-CSF) administration (12.5 +/- 7.0 vs 18.6 +/- 8.5 days, p = 0.001) and spent less time in hospital (23.7 +/- 10.9 vs 32.0 +/- 17.6 days, p = 0.009). Duration of antibiotic administration was also significantly shorter in the filgrastim group (13.6 +/- 7.6 vs 29.1 +/- 19.8 days, p = 0.001). CONCLUSION: In patients undergoing PBSCT following high-dose chemotherapy, filgrastim significantly reduced the duration of neutropenia, thrombocytopenia and days of G-CSF administration, and led to earlier hospital discharge compared with lenograstim.

Adjuvants, Immunologic↗

PubMed2002

A case of refractory Henoch-Schönlein purpura treated with thalidomide.

Henoch-Schönlein purpura is an acute, self-limited vasculitis syndrome which shows characteristic skin, joint, renal and gastrointestinal manifestations. It is common in childhood and may also occur in adults with fatal complications such as nephritis and gastrointestinal bleeding. We experienced a case of a 20-year-old woman who presented with palpable purpura and severe arthritis. The histopathologic examination of the skin revealed leukocytoclastic vasculitis with perivascular deposition of IgA and she was diagnosed with Henoch-Schönlein purpura. Despite treatment with prednisolone for one month, she had more aggravated purpura and fatal gastrointestinal bleeding. The symptoms were improved shortly by cyclophosphamide pulse therapy with plasmapheresis but symptoms were aggravated and symmetric mononeuropathy of the ulnar nerve developed. She was treated with 400 mg/day of thalidomide and symptoms were improved. We herein report a case of Henoch-Schönlein purpura successfully treated with thalidomide which was refractory to prednisolone, immunosuppressive drugs and plasmapheresis.

Adult↗