Enzyme system for improving the detection limit in pyrosequencing.

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.

Biliary cystadenocarcinoma followed up as benign cystadenoma for 10 years.

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.