Symptomatic gastrointestinal sarcoidosis: case report and review of the literature.
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Female↗
Biomedical subjects
Won Kyoo Cho
Publications and source records attributed to Won Kyoo Cho.
Transcriptional control of the human aldehyde dehydrogenase 2 promoter by hepatocyte nuclear factor 4: inhibition by cyclic AMP and COUP transcription factors.
An important regulatory element (designated FP330-3') of the ALDH2 promoter mediates activation by hepatocyte nuclear factor 4 (HNF4). This activation of promoter constructs containing this element by HNF4 was reduced by nearly half by 8-Br-cAMP in H4IIEC3 cells, an effect that was blocked by inhibitors of protein kinase A (PKA). Cotransfection assays showed that COUP-TF I, ARP-1, or PPARdelta suppressed the ability of HNF4 to activate the reporter. The repression was potentiated by 8-Br-cAMP. Electrophoretic mobility shift assays revealed that treatment of hepatoma cells or cultured rat hepatocytes with 1 mM 8-Br-cAMP or glucagon reduced binding of FP330-3' by HNF4 by half. In vitro phosphorylation of HNF4 by PKA decreased binding to FP330-3'. Fasting reduced the ALDH2 protein level in liver and kidney, two tissues expressing HNF4, but not heart. These data suggest that ALDH2 expression can be suppressed by cAMP, most likely through phosphorylation of HNF4 by PKA, and this may account for the reduction in enzyme protein during fasting.
Aldehyde Dehydrogenase↗
Characterization of regulatory volume decrease in freshly isolated mouse cholangiocytes.
Cell volume regulation plays a vital role in many cell functions. Recent study indicates that both K(+) and Cl(-) channels are important for the regulatory volume decrease (RVD) of cholangiocarcinoma cells, but its physiological significance is unclear due to the tumorous nature of the cells used. This present study reports the RVD of normal mouse cholangiocytes by using freshly isolated bile duct cell clusters (BDCC). A relatively simple and practical method of measuring the cross-sectional area of BDCCs by quantitative videomicroscopy was used to indirectly measure their volumes. Mouse cholangiocytes exhibited RVD, which was inhibited by 5-nitro-2'-(3-phenylpropylamino)-benzoate, DIDS, and glibenclamide, suggesting its dependence on certain chloride channels, such as volume-activated chloride channels. It is also inhibited by barium chloride but not by tetraethylammonium chloride, indicating its dependence on certain potassium channels. However, cAMP agonists had no significant effect on the RVD of BDCCs. This indirect method described can be used to study the RVD of cholangiocytes from normal as well as genetically altered mouse livers.
4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗