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Elaine Yeung

Publications and source records attributed to Elaine Yeung.

7 recordsLinked to original sources
PubMed2006

Hepatitis C virus core protein blocks interferon signaling by interaction with the STAT1 SH2 domain.

Emerging data have indicated that hepatitis C virus (HCV) subverts the host antiviral response to ensure its persistence. We previously demonstrated that HCV protein expression suppresses type I interferon (IFN) signaling by leading to the reduction of phosphorylated STAT1 (P-STAT1). We also demonstrated that HCV core protein directly bound to STAT1. However, the detailed mechanisms by which HCV core protein impacts IFN signaling components have not been fully clarified. In this report, we show that the STAT1 interaction domain resides in the N-terminal portion of HCV core (amino acids [aa] 1 to 23). This domain is also required to produce P-STAT1 reduction and inhibit IFN signaling transduction. Conversely, the C-terminal region of STAT1, specifically the SH2 domain (aa 577 to 684), is required for the interaction of HCV core with STAT1. The STAT1 SH2 domain is critical for STAT1 hetero- or homodimerization. We propose a model by which the binding of HCV core to STAT1 results in decreased P-STAT, blocked STAT1 heterodimerization to STAT2, and, therefore, reduced IFN-stimulated gene factor-3 binding to DNA and disrupted IFN-stimulated gene transcription.

Cell Line, Tumor↗
PubMed2003

Ramipril-associated hepatotoxicity.

CONTEXT: Angiotensin-converting enzyme inhibitors are prescribed for many cardiovascular and renal diseases. Adverse hepatic events, especially cholestasis, have rarely been reported with captopril, enalapril, lisinopril, and fosinopril. To date, hepatic injury associated with ramipril has not been reported. OBJECTIVE: To describe 3 patients who developed hepatitis, with or without jaundice, after receiving ramipril. DESIGN: Medical records and liver biopsies of the 3 patients were reviewed. Clinical, laboratory, and histologic findings were compared with findings in other cases of angiotensin-converting enzyme inhibitor-induced liver injury reported in the literature. RESULTS: The 3 patients were middle-aged men. In 2 patients, jaundice appeared 4 and 8 weeks after starting ramipril. Bilirubin levels peaked at 15.5 and 5 mg/dL, and alkaline phosphatase values peaked at 957 and 507 U/L. Aminotransferase levels were mildly elevated. Endoscopic retrograde cholangiopancreatography and ultrasonography showed no bile duct obstruction. Liver biopsies from the jaundiced patients were similar, with cholestasis, duct necrosis, and extravasation of bile, ductular proliferation, and portal inflammation. Cholestasis improved in 1 patient 6 weeks after stopping ramipril and was prolonged for 14 months in the other, in whom biliary cirrhosis was present on biopsy. The third patient developed hepatitis without jaundice 3 weeks after starting ramipril; symptoms resolved after stopping the drug. Ramipril-associated liver injury is similar to that seen with other angiotensin-converting enzyme inhibitors, but liver biopsy findings of duct necrosis and extravasation of bile have not been reported previously. CONCLUSION: Prolonged cholestatic hepatitis and biliary cirrhosis may result from the use of ramipril. Monitoring of liver enzymes is advisable for patients starting on ramipril.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2002

Monitoring adverse drug reactions to sulfonamide antibiotics in human immunodeficiency virus-infected individuals.

Patients infected with the human immunodeficiency virus (HIV) are at higher risk for adverse drug reactions from trimethoprim-sulfamethoxazole (TMP-SMX) than the HIV-negative population. Studying the HIV-positive population the authors aimed to validate the predictive and diagnostic value of the lymphocyte toxicity assay (LTA) for adverse drug reactions. Patient lymphocytes were analyzed for toxicity to SMX and TMP. Of 35 enrolled HIV patients, 18 had TMP-SMX hypersensitivity syndrome reaction (HSR); 10 tolerated the drug; and 5 had never received the drug. When cases with HSR were compared with controls that tolerated the drugs, cytotoxicity was higher for cases: 29.5% +/- 10.1% versus 19.3% +/- 11.2% for SMX (P < 0.022) and 25.0% +/- 11.9% versus 16.3% +/- 11.0% for TMP (P < 0.04). The authors' proposed threshold value for assigning positive results for TMP and SMX hypersensitivities was 22.5%. The LTA has a strong potential for use as a diagnostic tool to assess TMP-SMX hypersensitivity in HIV-infected individuals. Larger patient populations, as well as in vitro studies are needed to further address the reasons for elevated results in immunocompromised patients and to validate the usefulness of the test.

Adult↗