ABSTRACT
<p><b>OBJECTIVE</b>To study whether low-frequency pulsed electromagnetic fields promotes the differentiation of cultured rat osteoblasts through the cAMP/PKA signal pathway.</p><p><b>METHODS</b>Rat calvarial osteoblasts isolated by enzyme digestion were exposed to 50 Hz 0.6 mT low-frequency pulsed electromagnetic field for varying lengths of time, and the concentration of cAMP and levels of phosphorylated PKA in the cells were assayed. In cells treated with DDA to inhibit the activity of adenylate cyclase, the changes of ALP activity and transcription of osteogenic gene were detected after exposure to low-frequency pulsed electromagnetic field. The changes of osteogenic gene transcription and protein expression were tested in the osteoblasts pretreated with KT5720 in response to low-frequency pulsed electromagnetic field exposure.</p><p><b>RESULTS</b>The intracellular cAMP concentration in the cells increased significantly at 20 min during exposure to low-frequency pulsed electromagnetic field, began to decrease at 40 min during the exposure, and increased again after a 2-h exposure; the same pattern of variation was also observed in p-PKA level. Application of DDA and KT5720 pretreatment both suppressed the increase in ALP activity and osteogenic gene transcription induced by electromagnetic field exposure.</p><p><b>CONCLUSION</b>Low- frequency pulsed electromagnetic field exposure improves the differentiation of cultured rat osteoblasts by activating cAMP/PKA signal pathway.</p>
ABSTRACT
<p><b>OBJECTIVE</b>To study the expression of Galectin-3 in human hepatocellular carcinoma (HCC) tissues and the clinical value of serum Galectin-3 in the diagnosis of hepatocellular carcinoma.</p><p><b>METHODS</b>Immunohistochemistry method was used to detect the expression of Galectin-3 in the 46 pairs of HCC tissues and their para cancerous tissues. The relationship between expression levels of Galectin-3 and clinical parameters was analyzed. Serum Galectin-3 in different liver diseases were measured with ELISA. The sensitivity and specificity of galectin-3, alpha fetoprotein (AFP) and gamma-glutamyltranspeptidase II (GGT-II) for diagnosis of HCC were compared and the complementary diagnostic values of Galectin-3 and AFP and GGT-II for HCC were studied.</p><p><b>RESULTS</b>(1) The positive rate of Galectin-3 in the tissue of HCC was 78.2%, dramatically higher than that in para cancerous tissues (15.2%) (P is less than 0.01). The expression levels were correlated with differentiation and with the high expression in poor differentiation tissues; (2) Based on ROC curve, the cut-off of serum Galectin-3 for HCC diagnosis was set as 0.62mug/L, the serum galectin-3 positive rate was 64.5% in HCC cases, which was apparently higher than that in liver cirrhosis, chronic hepatitis and healthy persons (P is less than 0.05); (3) Serum Galectin-3 was not correlated with AFP and GGT-II. Combined determination of the three markers had the complementary diagnostic value for HCC and might increase the diagnostic sensitivity to 94.7%.</p><p><b>CONCLUSION</b>Galectin-3 is overexpressed in HCC tissues and is correlated with the tumor differentiation, suggesting that Galectin-3 may be associated with the carcinogenesis and development of HCC. Serum galectin-3 increases in the HCC cases and combined determination of serum Galectin-3, AFP and GGT-II can increase the diagnostic efficiency for HCC. Galectin-3 could be a novel serum tumor marker for HCC.</p>