Association of methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism with preterm delivery and placental abruption: a systematic review and meta-analysis.

INTRODUCTION: The aim of this study was to summarize evidence on the association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and odds of preterm delivery and placental abruption. MATERIAL AND METHODS: PubMed, EMBASE, CBM (Chinese Biomedical Database) and CNKI (Chinese National Knowledge Infrastructure) were searched to identify eligible studies published in English or Chinese before 12 August 2014. The pooled odds ratios (ORs) with 95% confidence intervals were estimated for the association of MTHFR C677T polymorphism with preterm delivery and placental abruption using random effects models. RESULTS: A total of 22 studies that met inclusion and exclusion criteria were included in this meta-analysis. Regardless of the genetic model tested we found no statistically significant association of MTHFR C677T polymorphism with preterm delivery or placental abruption. Funnel plots inspections, Begg's test and Egger's test did not show evidence of publication bias. CONCLUSIONS: This meta-analysis demonstrated that overall there was no association of MTHFR C677T polymorphism with preterm delivery or placental abruption.

Research Progress of the UPR Mechanism and its Effect on Improving Foreign Protein Expression.

The unfolded protein response (UPR) is a protective mechanism against endoplasmic reticulum (ER) stress that induces a series of signal transduction pathways to eliminate misfolded proteins. The UPR mechanism is highly conserved in fungi, higher organisms, plants and mammals. The UPR pathway is activated to stabilize ER functions when there are too many unfolded proteins or misfolded proteins in the ER. However, stress continues when ER proteins are stimulated by toxic substances that affect the balance of the UPR pathway, which causes changes in the structure and function of the ER and other organelles. These ultimately disrupt homeostasis in the body and cause pathological reactions that can be fatal. The UPR mechanism has clear effects on stabilizing the protein-folding environment. Dysfunction or disruption of the UPR mechanism is associated with numerous disorders, including neurodegenerative diseases, loss of control of protein secretion, cerebral ischemia and epilepsy, neuropsychiatric diseases, eye diseases, skin diseases, metabolic and inflammatory diseases, atherosclerosis, and heart disease. Thus, characterization of UPR function and its dysfunction has significant importance and has broad application prospects, which make research into the UPR a research hotspot.