Sam-Hyun Cho

Quantitative analysis of acyl-lysophosphatidic acid in plasma using negative ionization tandem mass spectrometry.

Analysis of acyl-lysophosphatidic acids (LPAs) has clinical importance as a potential biomarker for ovarian and other gynecological cancers or obesity from the point of view of prevention. Here we report a simple sample preparation and analytical method with high sensitivity and specificity for the early detection of gynecological cancers to improve the overall outcome of this disease. We established a novel quantification method for acyl-LPAs in plasma by electrospray negative ionization tandem mass spectrometry (MS-MS) using multiple reaction monitoring mode without conventional TLC step. Protein-bound lipids, acyl-LPAs in plasma were extracted with methanol/chloroform (2:1) containing LPA C(14:0) as internal standard under acidic conditions. Following back-extraction with chloroform and water, the centrifuged lower phase was evaporated and reconstituted in methanol and then analyzed. Using ESI-MS-MS with negative ionization MRM mode, all the species of LPAs were completely separated from plasma matrix without severe interference. For MRM mode, Q1 ions selected were m/z 409, 433, 435, 437 and 457 which corresponds to molecular mass [M-H](-) of C(16:0), C(18:2), C(18:1), C(18:0) and C(20:4) LPA, respectively. Q2 ions selected for MRM was m/z 79, phosphoryl product. Using MS-MS with MRM mode, all the species of LPAs were completely separated from plasma matrix without severe interference. This method allowed simultaneous detection and quantification of different species of LPAs in plasma over a linear dynamic range of 0.01-25 micromol/l. The method detection limit was 0.3 pmol/ml with correlation coefficient of 0.9983 in most LPAs analyzed. When applied to plasma from normal and gynecological cancer patients, this new method differentiated two different groups by way of total LPA level.

Genetic diversity of a Korean echovirus 5 isolate and response of the strain to five antiviral drugs.

An outbreak of echovirus 5 (ECV 5) occurred in Korea in 2006, marking the first time this virus had been identified in the country since enterovirus surveillance began in 1993. Using a sample isolated from a young male patient with aseptic meningitis, we performed sequencing of the Korean ECV 5 strain and compared it with a prototype strain (Noyce). At the nucleotide level, the P1 region (85.3%) had the highest identity value; at the amino acid level, the P3 region (98.0%) had the highest identity value. The two strains shared all cleavage sites, with the exception of the VP1/2A site, which was TY/GA in the Noyce strain but TR/GA in the Korean ECV 5 isolate. In Vero cells infected with the Korean ECV 5 isolate, no cytotoxicity was observed in the presence of azidothymidine, acyclovir, amantadine, lamivudine, or ribavirin, when the drugs were administered at a CC50 value >100 μg/mL. Of the five drugs, only amantadine (IC50: 1 ± 0.42 μg/mL, TI: 100) and ribavirin (IC50: 22 ± 1.36 μg/mL, TI: 4.55) had any antiviral activity against the Korean ECV 5 isolate.

Collision of three histologically distinct endometrial cancers of the uterus.

A collision tumor is defined by the presence of two separate masses in one organ, which are pathologically distinct. We described a 70-yr-old patient who complained of abnormal vaginal bleeding with a collision tumor of the uterine corpus. The patient received total hysterectomy, bilateral salphingo-oophorectomy, bilateral pelvic-paraaortic lymphadenectomy, omentectomy, and intraperitoneal chemotherapy. The uterine corpus revealed three separate masses, which were located at the fundus, anterior and posterior wall. Each tumor revealed three pathologically different components, which were malignant mixed müllerian tumor, papillary serous carcinoma, and endometrioid adenocarcinoma. Among these components, only the papillary serous carcinoma component invaded the underlying myometrium and metastasized to the regional lymph node. Adjuvant chemotherapy and radiation therapy were performed. The patient is still alive and has been healthy for the last 8 yr. We have reviewed previously reported cases of collision tumors which have occurred in the uterine corpus.