Fetal Chromosomal Abnormalities Screened by Non-invasive Prenatal Genetic Testing / 中国医科大学学报

Objective To explore the clinical significance of non-invasive prenatal genetic testing to screen prenatal fetal chromosomal abnormalities. Methods Peripheral blood was collected from 6 283 pregnant women who underwent non-invasive prenatal genetic testing at our hospital, and fetal DNA was extracted and purified for analysis. The complementary base principle of semiconductor chip technology was used to analyze all sequenced signals with BioelectronSeq 4000. Invasive prenatal diagnosis was performed in high-risk pregnant women according to the results of the sex chromosome sequencing signal analysis. Results Of the 6 283 pregnant women screened, 14 were found to have chromosomal abnormalities, and the positive rate was 0. 22％. Karyotype analysis was performed on 11 of the women; the remaining 3 refused to be diagnosed. Of these 11 women, 2 of the 5 patients with a high risk of XO were diagnosed with fetal chromosomal abnormalities (diagnosed as XO/XXX chimera and XO, respectively), and 3 were diagnosed with a normal karyotype; 5 patients with a high risk of XXY were diagnosed as XXY; and 1 patient with a high risk of XXX was confirmed as XXX. NIPT accuracy was measured to be 73％ (8/11). The detection rate of fetal chromosomal abnormalities by non-invasive prenatal genetic testing was significantly higher in the years 2015-2016 than in 2011-2014 (P ＜ 0. 05). Conclusion Non-invasive prenatal genetic testing for screening chromosomal abnormalities has a high accuracy rate and could improve the detection rate of fetal chromosomal abnormalities.

Comparison of the onset of uterine contractions determined from tocodynamometry and maternal perception.

The aim of this study was to investigate the time difference (TD) between the onset of uterine contraction (UC) determined from tocodynamometry (TOCO) and identified by maternal perception. The online available Icelandic database was used to calculate TD, which was defined as the difference between when it was felt by a pregnant woman and the starting point on the UC signal recorded by a TOCO. A total of 295 TDs from 78 recordings (from a total of 33 participants; among them, 13 participants included at least 3 recordings from different gestational weeks) were analyzed with the overall mean±SD of TD calculated. For each individual participant with at least 3 recordings, regression analysis was then performed to investigate the relationship between the mean TD from each recording with gestational week, with their overall slope calculated. The results showed that 85.4% of TDs was within [-40, 40] s, with an overall mean TD of 3.04 s (p>0.05), indicating that there was no significant difference between the UC onset determined from TOCO and maternal perception. It was also noticed that 61.5% recordings (48 out of 78 recordings) had all positive or negative TD for all the UCs analyzed within a recording. Furthermore, the regression analysis showed that the regression line slope was negative for 10 out of the 13 participants with at least 3 recordings from different gestational weeks, resulting in that the overall slope (-2.85±5.58) was significantly negative (p<;0.05), and indicating that UC onset TD decreased with gestational weeks. In summary, this study quantitatively investigated the TD between the onset of UCs determined from TOCO and maternal perception, providing scientific evidence for future studies to understand the underlying mechanism of the time sequence of UC activity determined from different techniques.

Comparison of electrohysterogram characteristics during uterine contraction and non-contraction during labor.

Uterine contraction is one of the most important indication in the labor progression. Electrohysterogram (EHG) is a promising method for monitoring uterine contraction and discriminating efficient and inefficient contractions. This study aims to analyze the difference of EHG signals between two groups. EHG signals are recorded with abdominal electrodes from 20 pregnant women, including 10 in term labor group and 10 in non-labor group. Typical linear and nonlinear characteristics of EHG signals, including root mean square (RMS), peak frequency (PF), median frequency (MDF), mean frequency (MNF), parameters from wavelet decomposition (W4, W5) and time reversibility (Tr) are extracted. These characteristics are compared between contraction and non-contraction in term labor group and non-labor group. The result shows that RMS, W4 and W5 of contraction are significantly larger than non-contraction both within term labor group and between two groups (all p<;0.001). However, MDF and MNF are significantly smaller (all p<;0.05). Furthermore, all characteristics of non-contraction show no significant difference between two groups, except MNF. The variability of RMS, W4, W5 and Tr of contraction are significantly larger than non-contraction both within term labor group and between two groups (all p<;0.05, with p<;0.001 for W5 and Tr). However, the variability of MDF, PF and MNF are significantly smaller (all p<;0.05). Moreover, the variability of all characteristics of non-contraction shows no significant difference between two groups, except MNF. We have shown that characteristics of EHG signals and their variability during contraction are quite different from non-contraction. Therefore, it is feasible to separate uterine contractions and monitor uterine activity with EHG signals.

Research progress of techniques of 7 T MRI system in brain imaging / 生物医学工程学杂志

7 T high field magnetic resonance imaging (MRI) provides a useful tool for microscopic spatial resolution visualizing anatomy. In addition, it enables the observation and analysis of tissue metabolism and function. 7 T MRI is now developing fast both in its technology and in its potential prospective medical applications. This review introduces current applications and possible future developments of the 7 T MRI in the field of human brain imaging for clinical studies and practices.

Research on EEG classification with evolving cascade neural networks / 生物医学工程学杂志

To correctly classify EEG with different mental tasks, a new learning algorithm for Evolving Cascade Neural Networks (ECNNs) is described to avoid over-fitting of a neural network due to noise and redundant features. The learning algorithm calculates the value of a fitness function on validate set and accordingly updates the connection weights on training set. The learning algorithm uses the regularity criterion for selecting the neurons with relevant connection. If the value Cr calculated for the rth neuron is less than the value Cr-1 calculated for the previous (r-1) neuron, the features that feed the rth neuron are relevant, else they are irrelevant. An ECNN starts to learn with one input node and then, adding new inputs as well as new hidden neurons, evolves it. The trained ECNN has a nearly minimal number of input and hidden neurons as well as connections. The algorithm is applied to classify EEG with two mental tasks. The trained ECNN has correctly classified 83.1% of the testing segments. It shows a better result, compared with a standard BP network.

Research on automatic diagnosis system of electrocardiogram / 中国医学物理学杂志

The duration of QRS wave,P wave and T wave of ECG can be computerized auto-detected with digital signal process and waveform recognition technology. It can diagnose 15 kinds of abnormal ECG such as ventricular presystole automatically and print out corresponding diagnosis reports. In order to verify the systems stability and creditability, we used American MIT-BIH database to test our algorithms and got a good result.

Effects of aminophylline used in the early stage of resuscitation on adenosine and vaso-active factors / 中国病理生理杂志

AIM:To investigate the effects of aminophylline used early in resuscitation on achievement ratio of resuscitation,the concentrations of plasma norepinephrine(NE),adenosine and nitric oxide(NO),and the levels of cardiac tissue endothelin-1(ET-1)and adenosine in rats with sudden cardiac arrest.METHODS:Sixty SD rats were randomly divided into three groups:operated control(group A),epinephrine treatment(group B),and epinephrine plus aminophylline treatment(group C).Each group had 20 rats.The concentrations of plasma NE,adenosine and NO,and the levels of cardiac tissue ET-1 and adenosine were examined in group A and 30 min after survived in group B and group C.RESULTS:The duration of circulation recovered in group C was less than that in group B,significantly(P0.05).The concentrations of plasma adenosine and NE,and the levels of cardiac tissue ET-1 and adenosine in group B and group C were higher than those in group A significantly(P