Differential Gene Expression Identified in Complete Hydatidiform Mole by Combining Suppression Subtractive Hybridization and cDNA Microarray

Complete hydatidiform mole (CHM) is a type of gestational trophoblastic disease with pure paternal chromosome contribution and unpredictable malignant potential. As an attempt to assess the molecular pathogenesis of CHM, suppression subtractive hybridization (SSH) combined with cDNA microarray was used to compare the gene expression pattern of CHM compared with normal first-trimester placenta of similar gestational ages. cDNA microarray analysis using tissue-specific chips constructed with subtracted cDNA libraries identified 13 differentially expressed gene transcripts. Quantitative real-time polymerase chain reaction (PCR) confirmed up-regulation of human chorionic gonadotropin beta subunit (CGB) (P=0.0008) and KIAA1200 (P=0.0005), a G-protein regulator, as well as down-regulation of osteopontin (SPP1) (P<0.0001) in 14 genotyped CHM when compared with 15 normal placentas. These candidate genes may contribute toward understanding the mechanism involved with the development and progression of CHM.

Dissolution rates of limestones of different sources

The dissolution characteristics of limestones from six sources in Taiwan have been studied by using the pH-stat method in a stirred tank at 60 degrees C, pH values of 4 and 6, stirrer speeds of 500-1000 rpm, and a particle size of 75-125 microm aperture width. The dissolution rates of the limestones were found to be controlled by the mass transfer of hydrogen ions with chemical reactions in the liquid film surrounding the limestone particle. The measured value of mass transfer coefficient increases with an increasing pH value and stirrer speed and remains constant with particle size. For the six limestones at the same particle size, the measured dissolution rates per unit area are the same due to the mass-transfer control kinetics; however, the time taken to reach a certain fraction of dissolution is proportional to the molar concentration of the soluble species in the limestone and the initial particle size.