Red tiger top gel separator tubes

200 serum samples and placentas from pregnancies were obtained from the Taizhou People’s Hospital including 50 early onset preeclampsia pregnancies, 50 pregnancies at 20–33 gestational weeks, 50 late onset preeclampsia pregnanciesa and 50 pregnancies at 34–41 gestational weeks collected in red tiger-top gel separator tubes (Thermo Fisher Scientific, Shanghai, China). Preeclampsia was defined as hypertension—systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg, on at least 2 occasions, at least 4 h apart. Patients with diabetes mellitus, PE premature ruptured membranes without labor, multiple gestations, and fetal demise in utero or fetal anomalies were excluded from this study.
Immediately after delivery, the overlaying fetal membranes were removed and several small pieces of placental tissues were randomly collected, blotted on clean tissue paper to remove excess blood and placed in cryotubes containing RNAlater (Qiagen Inc., Valencia, California), at 4 to 1 volume of tissue.
Participants fasted overnight prior to tests under standardized conditions. Fasting blood samples were taken from participants and collected. After separated by centrifugation at 10,000 x g and kept at −80°C until use. Clinicopathological features in 200 patients were displayed in Table 1 and the outcomes of 200 patients were displayed in Table 2.

Blood samples were collected in red tiger-top gel separator tubes (Thermo Fisher Scientific Inc., Waltham, MA, USA) from patients or healthy donors. All samples were processed within 2–5 h after collection as follows: the serum was separated by centrifugation at 1,200 × g at 4°C for 20 min and passed through a 13-mm serum filter (Thermo Fisher Scientific Inc.). Serum was divided into aliquots and flash frozen at −80°C until total RNA isolation.