Sensitivity of Human Cancer Cells to the New Anticancer Ribo-nucleoside TAS–106 Is Correlated with Expression of Uridine-cytidine Kinase 2

TAS–106 [l–(3– C -ethynyl-β- d - ribo -pentofuranosyl)cytosine] is a new anticancer ribo -nucleoside with promising antitumor activity. We have previously presented evidence suggesting that the TAS–106 sensitivity of cells is correlated with intracellular accumulation of the triphosphate of TAS–106, which may be affected both by cellular membrane transport mechanisms and uridine-cytidine kinase (UCK) activity. Since the presence of a UCK family consisting of two members, UCK1 and UCK2, has recently been reported in human cells, we investigated the relation between expression of UCK1 and UCK2 at both the mRNA and protein levels and UCK activity (TAS–106 phosphorylation activity) in a panel of 10 human cancer cell lines. Measurement of UCK activity in these cell lines revealed that it was well correlated with the cells' sensitivity to TAS–106. In addition, the mRNA or protein expression level of UCK2 was closely correlated with UCK activity in these cell lines, but neither the level of expression of UCK1 mRNA nor that of protein was correlated with enzyme activity. We therefore compared the protein expression level of UCK2 in several human tumor tissues and the corresponding normal tissues. Expression of UCK2 protein was barely detectable in 4 of the 5 human tumor tissues, but tended to be high in the pancreatic tumor tissue. It could not be detected at all in any of the normal tissues. Thus, expression of UCK2 appeared to be correlated with cellular sensitivity to TAS–106, and it may contribute to the tumor-selective cytotoxicity of TAS–106.     

Thoracic aortic dissection in a patient with autosomal dominant polycystic kidney disease treated with maintenance hemodialysis

A patient with autosomal dominant polycystic kidney disease (ADPKD) on maintenance hemodialysis (HD) experienced spreading back pain with a sudden onset, and was diagnosed with thoracic aortic dissection. Reports of ADPKD with aortic dissection are rare. Hypertension, which is essentially universal both among ADPKD and hemodialysis patients, is a known risk factor for aortic dissection. Additionally, some reports have indicated that patients with ADPKD have aortic fragility. We suspect that aortic dissection may be less rare than presently apparent among HD patients with ADPKD.     

High throughput detection of drug-metabolizing enzyme polymorphisms by allele-specific fluorogenic 5' nuclease chain reaction assay

We have developed an allele-specific fluorogenic 5' nuclease chain reaction assay for detecting polymorphisms in the following human drug-metabolizing enzyme genes: CYP2C9 (CYP2C9*2 and *3), CYP2C19 (CYP2C19*2 and *3), CYP2D6 (CYP2D6*4, *10, *14, *18, and *21(C8)), N-acetyltransferase 2 (NAT2*5B, *6A, and *7B), thiopurine methyltransferase (TPMT*3C), and aldehyde dehydrogenase2 (ALDH2*2). This method is a marriage of two emerging technologies, the use of allele-specific amplification primers for target DNA and hybridization of the TaqMan probe. The TaqMan probe is labeled with both a fluorescent reporter dye and a quencher dye. Genotypes are separated according to the different threshold cycles of the wild-type and mutant primers. All assays are performed using a single thermocycling protocol. This genotyping method is rapid and highly sensitive and yields a high throughput. It could be applied toward automated large-scale genotyping.     

Optical coherence tomography for observation of the olfactory epithelium in mice

Objective

Optical coherence tomography (OCT) is an imaging tool that exploits the coherence of infrared light and is clinically utilized in the field of ophthalmology and dermatology. This study aimed to examine the feasibility of using OCT for diagnosing degeneration and regeneration of the olfactory epithelium in mice.