A method for improving the accuracy of non-invasive prenatal screening by cell-free foetal DNA size selection

Background Non-invasive prenatal screening (NIPS) using cell-free foetal DNA (cfDNA) has been widely used for identifying common foetal aneuploidies (e.g. trisomy 21 (T21), trisomy (T18) and trisomy 13 (T13)) in clinical practice. The sensitivity and specificity of NIPS exceeds 99%, but the positive prediction value (PPV) is approximately 70% (combined T21, T18 and T13). Thus, some 30% of pregnant women who have positive NIPS results are eventually identified as normal by amniocentesis. These women therefore must undertake needless invasive tests and risk miscarrying healthy babies because of false positive NIPS results. Methods In order to achieve higher accuracy, we amended the standard NIPS (s-NIPS) protocol with an additional cfDNA size selecting step in agarose-electrophoresis. The advantage of the new method (named e-NIPS) was validated by comparing the results of e-NIPS and s-NIPS using 114 retrospective cases selected from 15,930 cases. Results Our results showed that the foetal cfDNA fraction can be enriched significantly by a size selection step. With this modification, all 98 negative cases and 9 of 11 false positive cases of s-NIPS were correctly identified by e-NIPS, resulting in an increased PPV from 71% to 77%. Additionally, a simulation test showed that e-NIPS is more reliable than s-NIPS, especially when the foetal cfDNA concentration and sequencing coverage are low. Conclusion cfDNA size selection is an important step in improving the accuracy of non-invasive prenatal screening for chromosomal abnormalities.

Effects of Δ(9)-tetrahydrocannabinol (THC) on human amniotic epithelial cell proliferation and migration

BACKGROUND

The deleterious effects of cannabis consumption for fertility and pregnancy outcome are recognized for years. The main psychoactive molecule of cannabis, Δ(9)-tetrahydrocannabinol (THC) is able to cross the placenta barrier and cause alterations in fetal growth, low birth weight and preterm labor. However, the effects of THC on the human placenta amnion are still unknown.

METHODS

The distributions of CB1R and CB2R in human amnion tissues were observed by immunohistochemistry (IHC). Human amniotic epithelial cell proliferation and migration in response to THC treatment were measured by MTS and transwell assays, respectively. The PCR array was performed to study the key regulators involved in the cell migration. The protein levels of CB1R, CB2R in amnion tissues and MMP2, MMP9 in cells were detected by western blotting. Small interfering RNAs (siRNAs) were used to knockdown MMP2 and MMP9 in WISH cells.

RESULTS

Our results indicated that both CB1R and CB2R primarily identified in the epithelial layer of human placental amnion tissue. The CB1R expression in the amnion tissue was higher in the preterm group than normal control. High-dose of THC (30uM, but not 20 and 10uM) significantly inhibited (p<0.01) human amniotic epithelial cell lines (WISH) proliferation. Meanwhile, THC at both 10uM and 20uM (p<0.05) significantly suppressed cells migration in both WISH and primary human amniotic epithelial cells. The PCR array data and siRNA experiments demonstrated that MMP2/9 were tightly involved in the regulation of THC-inhibited cell migration in WISH cells.

CONCLUSION

These results suggested that THC inhibited the migration of human amniotic epithelial cell through the regulation of MMP2 and MMP9, which in turn altered the development of the amnion during the gestation and partially resulted in preterm labor and other adverse pregnancy outcomes.

[Purity measurement of hybrid rice seed Yixiang 725 with visible-near infrared reflectance spectra]

A rapid and non-invasive method was put forward to measure the purity of hybrid rice seed by visible-near infrared reflectance spectra. Ninety hybrid rice seed samples (Yixiang 725) with the purity of 90%-99% were collected using a FieldSpec 3 visible-near infrared spectometer. All samples were divided randomly into two groups, one group with 75 samples used as calibrated set, and the other with 15 samples used as validated set. Based on the spectra in the range of 380-2 400 nm, the regression model was established using the PLS (partial least square), and different spectra pretreatment methods were compared. The study showed that spectra information can be extracted thoroughly by the pretreatment method of first derivative combined with standard normal variate, with the SEC (standard error of calibration) of 0.002 5, SEP (standard error of prediction) of 0.006 6, and determination coefficients of 0.988 4 (calibration set) and 0.922 7 (validation set) respectively. The spectra, which were pretreated with the method of first derivative combined standard normal variate, were analyzed by principal component analysis (PCA). The top 20 principal components, which were computed by PCA and accounted for 86.09% variation of the original spectral information, were used to build BP-ANN model for measuring the purity of hybrid rice seed as the new variables. The study showed that the SEC and SEP of BP-ANN model were 0.001 7 and 0.006 1, and the determination coefficients of that were 0.995 2 (calibration set) and 0.936 9 (validation set) respectively. Therefore, the predictive power of BP-ANN model was better than that of PLS model. Results indicated that it was feasible to measure the purity of the hybrid rice seed by visible-near reflectance spectra as a rapid and non-contact way, and PCA combined with BP-ANN was a preferred method.

Effect of morphine and electro-acupuncture (EA) on apoptosis of thymocytes

The influence of morphine and EA on the apoptosis of thymocytes were studied to investigate the posibility of its involvement in the mechanism of morphine-induced immunosuppression and the regulatory effect of EA on it. 1h after injecting 50 mg/kg morphine subcutaneously into 3-wk old Balb/c mice continually twice a day for 5 days, thymus was collected and the apoptotic cell was detected by a method of terminal deoxynucleotidyl transferase-meditaed dUTP nick end-labeling(TUNEL). The results showed that morphine significantly enhanced the percentage of TUNEL positive cells inside thymus with an appearing of apoptotic DNA ladder after 24 h incubation. Treating mice with EA of "Zusanli(St.36)" and "Lanwei(Ext.33)" for 1h after morphine administration decreased the percentage of TUNEL positive cells. EA also showed an regulatory effect on the increased the expression of CPP32 and decreased the expression of Bcl-2 by morphine. The significant enhancement of hypothalamic CRF and plasma ACTH level by morphine and the antagonize effect of EA on it suggested a possible role of Hypothalamus-pituitary-adrenal (HPA) axis played in the apoptosis of thymocytes by morphine and the regulatory effect of EA.

Effect of electroacupuncture on the activities of tyrosine protein kinase in subcellular fractions of activated T lymphocytes from the traumatized rats

The present study was to observe the dynamic changes of tyrosine protein kinase (TPK) activity in subcellular fractions in the early stage of activation of T lymphocytes from normal and traumatized rats, and the regulatory effect of electroacupuncture (EA) stimulation on it. The results showed that the activities of TPK in membranous and cytosolic fractions of activated T lymphocytes were increased on second 5, and the peak was on scond 45 after ConA stimulation. Then it was decreased gradually. Comparing with the control group, the activities of TPK in membranous and cytosolic fractions of activated T lymphocytes from the traumatized rats were inhibited in various degrees especially in membrane. EA of "Zusanli"(ST-36) and "Lanwei"(Extra 33) points could enhance the activity of TPK in subcellular fractions of activated T lymphocytes from the traumatized rats. The results indicated that EA stimulation could prevent the inhibition of activation of TPK induced by trauma stress, and contribute to transmembrane signal transduction of T lymphocytes.

Effect of continued electroacupuncture on induction of interleukin-2 production of spleen lymphocytes from the injured rats

The present study was to investigate the dynamic changes of the induction of interleukin-2 (IL-2) production of spleen lymphocytes from the rats after operative trauma stress and the regulatory effect of continued electroacupuncture (EA) stimulation of "Zusanli" (St. 36) and "Lanwei" (Extra 33) points on the induction of IL-3 production of spleen lymphocytes from the injured rats. The results showed that the induction of IL-2 production of the rat spleen lymphocytes was significantly decreased on day 1, 3, 5, 7 (P < 0.05), and the minimum level was on day 3 after operative trauma at both dilution 1:8 and dilution 1:16. The induction of IL-2 production was reserved to nearly normal on day 10. Continued stimulation by EA on "St. 36" and "Extra 33" points on day 3, 5, 7 increased the induction of IL-2 production in various degrees at the two dilutions (P < 0.01), or P < 0.05). The results mentioned above implied that the immune function could be depressed by trauma stress. Continued EA stimulation could improve the immunosuppression induced by trauma stress.

[Effects of tanshionone to bleomycin induced pulmonary fibrosis of rats on histological changes and production of lipid peroxides and hydroxyproline]

Study was designed to explore the effect of sodium tanshionone IIA sulfonate on bleomycin-induced pulmonary fibrosis in rat. The amount of lipid peroxides (LPO), hydroxyproline in rat lung tissue homogenate was determined at 3, 7, 14, 28 day after administration respectively. The results suggest that the amount of LPO, hydroxyproline of rat lung homogenate were significantly decreased in sodium tanshionone IIA sulfonate group. In addition, histological changes and width of alveolar septa and percentage area of pulmonary fibrosis scars was measured. The results show that sodium tanshionone IIA sulfonate could ameliorate bleomycin induced pulmonary fibrosis in rat. The mechanism that sodium tanshionone IIA sulfonate could prevent and treat bleomycin-induced pulmonary fibrosis in rat was discussed.

The nature of zinc in cytochrome c oxidase

The zinc ion in bovine heart cytochrome c oxidase can be completely depleted from the enzyme with mercuric chloride without denaturing the protein. The metal atom stoichiometry of 5Cu/4Fe/0Zn/2Mg obtained for the enzyme following HgCl2 treatment indicates that this depletion is highly selective. Zinc depletion exposes one cysteine on subunit VIa and one cysteine on subunit VIb for N-iodoacetyl-N'-(5-sulfo-1-naphthyl)ethylene-diamine (1,5-I-AEDANS) labelling, suggesting that the zinc plays a structural role in the protein by providing a bridge between these two subunits. Although the treatment of cytochrome c oxidase with mercuric chloride inhibits the steady-state activity of the enzyme, subsequent removal of the Hg2+ bound to cysteine residues by 1,5-I-AEDANS significantly reverses the inhibition. This latter result indicates that the removal of the zinc itself does not alter the steady-state activity of the enzyme.