We describe a case of biliary cystadenocarcinoma that showed a longterm clinical course. A 69-year-old Japanese man was admitted to our hospital because of abdominal discomfort. The patient had been diagnosed with benign cystadenoma of the liver at another hospital in 1987 and had been followed up for 10 years. Abdominal ultrasonography (US) and computed tomography (CT) scan demonstrated a unilocular cystic lesion, which included multiple conspicuous papillary protrusions in the left hepatic lobe. Left lateral segmentectomy was performed, and intraoperative cholangiography revealed a communication between the cystic tumor and intrahepatic bile duct. The tumor contained clear mucinous fluid and enfolded multiple yellowish papillary projections on the cystic wall. Histological examination showed the tumor to be biliary cystadenocarcinoma. The patient is doing well 4 years after the operation.
The rigidity G and the viscosity η of monodisperse polystyrene latexes were measured by the torsional quartz crystal method at 70 kHz, and an abrupt change in G and η was found at the order-disorder transition of the latexes. The torsional quartz crystal method was improved for measurements with aqueous conductive samples, and a careful calibration showed that G and η are obtained if the dielectric constant of the sample is known. In the ordered state of latex with a volume concentration of 9.3%, the apparent rigidity G and the viscosity η were about 1.5×103 dyne/cm2 and 0.6 cp, respectively, while in the disordered state G was small and η was 0.95 cp. Ordered latex is a “crystal” formed by the screened Coulomb repulsion and is a good model not only for crystals but also for ordered structures in some biological systems.
Highly sensitive real-time pyrosequencing seems promising for constructing an inexpensive and small DNA sequencer with a low running cost. A DNA sample of a picomole level is usually used in the conventional pyrosequencing based on a luciferase assay coupled with an APS-ATP surfurylase reaction for producing ATP from pyrophosphate (PPi). Although the luminescence intensity could be increased by increasing the amount of luciferase, it was impossible to reduce the target DNA amount because of a large background luminescence due to the luciferase-APS reaction. In this report, a novel approach using a new conversion reaction of PPi to ATP is proposed. This method has a very low background and can produce high signals in the presence of a large amount of luciferase; thus, the sample amount required for sequencing is significantly reduced. The ATP production from PPi is catalyzed with pyruvate orthophosphate dikinase (PPDK) using AMP and phosphoenolpyruvate as the substrates, which are inactive for the luciferase-catalyzed reaction. All of the components in the AMP-PPDK-based pyrosequencing system are suitable for highly sensitive DNA sequencing in one tube. Real-time DNA sequencing with a readable length up to 70 bases was successfully demonstrated by using this system. By increasing the amount of luciferase, as low as 2.5 fmol of DNA templates was accurately sequenced by the proposed method with a novel simple and inexpensive DNA sequencer having a photodiode array as a sensor instead of a PMT or CCD camera. A sample amount as low as 2 orders of magnitude smaller than that used in the conventional pyrosequencer can be used.
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