Research Advances in the Role of RAS-GTPase-activating Proteins in Tumors / 中国医学科学院学报

A variety of molecules are involved in tumorigenesis,during which the RAS pathway-related molecules play key roles. RAS gene mutations exist in about 30% of human tumors;in some tumors(e.g. pancreatic adenocarcinomas),the mutation rates may rise to 75%-95%. Even in tumors without RAS mutations,the RAS pathway-related molecules can also be highly activated. RAS-GTPase-activating proteins(RASGAPs)are a group of tumor suppressors. They normally turn off RAS pathway by catalyzing the hydrolysis of RAS-GTP. However,the mutation or hypermethylation of their promoters will inactivate their roles and thus provide an alternative mechanism of activating Ras. This article reviews the research advances in the role of RASGAPs in the development of tumors.

Pulse signal analysis of patients with coronary heart diseases using Hilbert-Huang transformation and time-domain method / 中国结合医学杂志

<p><b>OBJECTIVE</b>To explore characteristic of pulse signal to distinguish patients with coronary heart diseases (CHD) from patients without CHD and healthy adults, and accordingly evaluate the potential role of pulse signal to diagnosis CHD.</p><p><b>METHODS</b>Totally 407 patients enrolled from 4 collaborating medical centers were assigned to a CHD group (205 patients) and a non-CHD group (202 patients). The healthy control group (62 adults) enrolled from Shanghai University of Traditional Chinese Medicine. Pulse signals were collected using the synchronous multiplex pulse signal acquisition system. The pulse signals were analyzed and extracted using Hilbert-Huang transformation (HHT) and time-domain, respectively. The time-domain parameters of pulse signal were processed by the analysis of variance (SNK test).</p><p><b>RESULTS</b>Special patterns in the CHD group pulse signal were found in this study: (1) time-domain parameters of pulse signal, h1, h3, h4, h3/h1, ts, t4/t were increased and w was wider; (2) 44% of C2 waves in HHT were chaotic and disordered and 72% of C waves were exhibited irregularly with average amplitude over 10 g-forces, which were all significantly different from controls.</p><p><b>CONCLUSION</b>Characteristic wave and time-domain parameters of pulse signal were extracted using HHT and time-domain which could be served as a non-invasive approach for assessing patients with CHD.</p>

Comparison of computed tomography versus magnetic resonance imaging in assessing radiofrequency ablation margins after radiofrequency ablation in patients with hepatocellular carcinomas / 中国医学科学院学报

<p><b>OBJECTIVE</b>To assess the diagnostic value of magnetic resonance imaging (MRI) in the follow-up of patients with hepatocellular carcinomas treated with radiofrequency ablation (RFA) and to compare it with that of computed tomography (CT).</p><p><b>METHODS</b>From December 2009 to September 2011, 40 patients (47 hepatocellular carcinomas) were treated with RFA after transcatheter arterial chemoembolization and underwent MRI and CT for follow-up. RFA margins were assessed on a five-point scale with receiver operating characteristic curve analysis. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were evaluated.</p><p><b>RESULTS</b>The interobserver agreement rate for MRI was significantly higher (Kappa=0.935) than for CT (Kappa=0.714; P < 0.05). The scores of 1 and 5 points for MRI, which confirms the presence or absence of residual tumor, accounted for 89.4% (84/94), while for CT accounting for only 31.9% (30/94). The area under the receiver operating characteristic curve of MRI was significantly higher than that of CT (P < 0.05), as were the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of detection rate (mean, 100%, 96.4%, 76.9%, 100%, and 96.8% for MRI, respectively, vs. 30.0%, 57.1%, 10.3%, 87.7%, and 63.8% for CT).</p><p><b>CONCLUSION</b>MRI is superior to CT in assessing the RFA margins in terms of the diagnostic accuracy and detection rate .</p>