ObjectivesTo systematically review the association between pregnancy-induced hypertension (PIH) and preterm birth in mainland China.MethodsPubMed, The Cochrane Library, ScienceDirect, Web of Science, CBM, CNKI, WanFang Data and VIP databases were electronically searched to collect studies on the association between PIH and preterm birth in mainland China from January, 2007 to March, 2019. Two reviewers independently screened literature, extracted data and assessed risk of bias of included studies; then, meta-analysis was performed by using Stata 12.0 software.ResultsA total of 48 studies were included, involving 43 276 cases of premature birth, 527 995 cases of full-term control group, in which there were 3 446 cases of PIH in premature delivery, with a prevalence rate of 7.96%. There were 14 099 cases of PIH in the full-term control group, with a prevalence rate of 2.67%. The results of meta-analysis showed that PIH was associated with preterm birth (OR=3.27, 95%CI 2.64 to 4.05, P<0.001). The overall population attributable risk was 13.0%. Subgroup analysis was conducted for different study types, and the results were unaltered.ConclusionsThe current evidence shows that PIH is associated with preterm birth. During pregnancy, the management and intervention of pregnant females with gestational hypertension should be strengthened, and active treatment should be supervised to prevent the occurrence of premature birth.
ObjectiveTo explore the relationship between the oxygen partial pressure of mice hindlimb muscles with normal blood supply or ischemia and expression of HIF-1αprotein, and to provide a theoretical basis for the study of angiogenesis in vitro hypoxia. MethodsMice hind limb ischemia model were established, tissue oxygen tension of gastrocnemius muscle and bone marrow were measured by micro electrode at different time points of ischemia (24 hours, 1 week, 2 weeks, 3 weeks, and unoperated as control). Protein level of hypoxia inducible factor-1αand histological examination were performed on gastrocnemius muscle as well. ResultsThe oxygen tension baselines of gastrocnemius muscle and femoral bone marrow was (47.78±4.37) mm Hg and (21±3.40) mm Hg, respectively. Muscle oxygen tension decreased significantly at all time points after modeling (P < 0.05), and reached lowest level in 1 week of ischemia. The inflammatory reaction was most serious and HIF-1αprotein reached highest level at the same time point. With the extension of ischemic time, the tissue oxygen tension recovered while HIF-1αlevel was down-regulated, however, There was no statistical correlation(r=-0.86, P > 0.05). Oxygen tension in bone marrow didn't show any significant change at all time points. ConclusionsThe expression level of HIF-1αprotein in ischemic tissue can reflect the degree of ischemic limb. The concept that physiological oxygen level differs in different tissue is highlighted, and may provide basis for ex vivo hypoxic research.