Hyojin Lee

Self-selection in the self-assembly of isomeric supramolecular squares from unsymmetrical bis(4-pyridyl)acetylene ligands.

A new approach wherein steric interactions between substituents of unsymmetrical bis(4-pyridyl)acetylene ligands dictate the self-selection of single isomers of [4 + 4] self-assembled squares is presented. Each [4 + 4] self-assembly is characterized by multinuclear (31)P and (1)H NMR spectroscopies and electrospray ionization mass spectrometry. NMR spectroscopic studies are used to provide a means of evaluating the efficiency of bulky substituents at proximal or remote positions relative to the Pt-N bonding motif to direct self-selection. Molecular modeling using the MMFF force field is utilized to determine the relative energy of different isomers of each assembly, and modeling results reasonably explain the trend in self-selectivity with varying pyridyl substitution.

Time-course changes in the expression levels of miR-122, -155, and -21 as markers of liver cell damage, inflammation, and regeneration in acetaminophen-induced liver injury in rats

Drug-induced liver injury (DILI) is a significant threat to patient health and a major concern during drug development. Recently, multiple circulating microRNAs (miRNAs) have been reported to be potential biomarkers for DILI. To adapt and validate miRNAs for clinical use, we investigated the time-course changes in miR-122 expression levels in an acetaminophen-induced liver injury model in rats. In addition, miR-155 and miR-21 were evaluated as makers of inflammation and regeneration, respectively, to characterize liver status. Our results revealed that miR-122 is an early and sensitive biomarker of hepatocellular injury at a stage when alanine transaminase, aspartate transaminase, and total bilirubin were not detectable. However, no significant differences in the expression levels of other miRNAs (miR-155 and -21) were observed between treatment and vehicle groups. Collectively, these time-course changes in the expression levels of miRNAs may be useful as markers for clinical decision-making, in the diagnosis and treatment of DILI.

A serological study of severe fever with thrombocytopenia syndrome using a virus neutralization test and competitive enzyme-linked immunosorbent assay

Severe fever with thrombocytopenia syndrome (SFTS) is caused by the SFTS virus (SFTSV). The SFTSV appears to have a wide host range, as SFTSV-positive ticks have been isolated from both farm animals and wild rodents. Therefore, it is important to monitor SFTSV-positive animals to prevent the transmission of SFTSV from animals to humans. Previously, we developed a competitive enzyme-linked immunosorbent assay (cELISA) to detect SFTSV-specific antibodies from field animals and compared the cELISA results to those from an indirect immunofluorescence assay (IFA). In this study, cELISA results were compared to and evaluated against the results from both an IFA and a virus neutralization (VN) test of 193 bovine serum samples (including two bovine positive control sera) and 70 horse serum samples. The consistency (98.9%) between cELISA and VN results was higher than that (97.4%) between cELISA and IFA for the bovine serum samples. Similarly, for the horse serum samples, the consistency (88.6%) between cELISA and VN results was higher than that (84.3%) between the cELISA and IFA. These findings indicate that our newly developed cELISA can be used for surveillance or epidemiological studies of SFTSV in animals.

Significance of EZH2 expression in canine mammary tumors.

BackgroundCurrent studies report that aberrations in epigenetic regulators or chromatin modifications are related to tumor development and maintenance. EZH2 (Enhancer of zeste homolog 2) is one of the catalytic subunits of Polycomb repressive complex 2, a crucial epigenetic regulator. EZH2 has a master regulatory function in such processes as cell proliferation, stem cell differentiation, and early embryogenesis. In humans, EZH2 is linked to oncogenic function in several carcinomas, including breast cancer, and dysregulation of EZH2 has been particularly associated with loss of differentiation and the development of poorly differentiated breast cancer. In our present study, we were interested in determining whether EZH2 is increased in canine mammary tumors, which show similarities to human breast cancer.ResultsInvestigation of the expression of EZH2 in canine mammary tumors revealed that EZH2 protein was overexpressed in canine mammary carcinomas, as in human breast cancer. In addition, the immunohistochemical expression level of EZH2 was associated with the degree of malignancy in canine mammary carcinoma. This is the first report to describe EZH2 expression in canine mammary tumors.ConclusionsBecause the expression of EZH2 was similar in canine mammary carcinoma and human breast cancer, spontaneous canine mammary tumors may be a suitable model for studying EZH2 and treatment development.