Objective To analysis the incidence and management of monozygotic twin (MZT) conceived by assisted reproductive techniques (ART). Methods A retrospective analysis of clinical pregnancies and MZT that resulted from ART was performed in Reproductive Medical Center,the First Affiliated Hospital,Wenzhou Medical University between January 2011 and January 2014. Results A total of 5 908 pregnancies were diagnosed: 2 012 twins, 157 high-order multiple pregnancy (HOMP), including 4 quadruplets. Overall, 51 MZT pregnancies were identified of them including 32 cases HOMP and 19 cases MZT. The incidence of MZT resulting from cleavage-stage embryo transfer was similar to blastocyst transfer (P=0.960). The percent of MZT resulting from in vitro fertilization [0.93% (28/3 022)], frozen-thawed embryo transfer [0.87% (13/1 502)] and intracytoplamic sperm injection [0.72% (10/1 384)] did not show statistical significance (P=0.794). The expectantly managed MZT was associated with a significantly greater likelihood of miscarriage [6/19 vs 5.11% (101/1 976)], and low birth weight infant [73.91% (17/23) vs 42.89% (1 453/3 388), P<0.01], when compared with dizygotic twin (DZT) did not undergo selective embryo reduction(SER). In monozygotic (MZ)-triplets with SER to 2 fetuses or to 1 fetus, there was no cases of preterm birth or low birth weight infant observed in MZ-triplets with SER to 1 fetus;when compared with MZ-triplets with SER to 2 fetuses, the low birth weight infant [56.00% (14/25), P=0.021] has statistical significance. The likelihood of the survival of two babies was lower in MZ-triplets with SER to 2 fetuses when compared with non-MZ triplets with SER to 2 fetuses [42.86%(9/21)vs 75.21%(91/121), P=0.003]. Conclusions The incidence of MZT pregnancies following ART is high. It plays a significant role in the occurrence of HOMP. MZT pregnancies are at an increased risk of adverse outcomes , it should transform to a single embryo thansfer (SET) program to reduce them incideuce. Reduction of MZT contained in multiple pregnancies appears to be a safe option.

OBJECTIVETo study the effect of laminarin polysaccharide (LP) on the activity of matrix metalloproteinase of photoaging skins.

METHODKunming SPF mice were prepared with back hair shaved, and randomly divided into the control group, the model group, the LP low does group (LP-L, 1 mg x kg(-1)), the LP high dose group (LP-H, 5 mg x kg(-1)) and the Vit E (100 mg x kg(-1)) group. They were abdominally injected with drugs twice on a daily basis. Except for the control group, all groups were exposed to ultraviolet rays for 1 hour every day, five times on a weekly basis, with accumulated exposure dose of UVB being 21.60 J x cm(-2) and accumulated exposure dose of UVA being 84.02 J x cm(-2). Eight weeks later, exposed back skins were collected to detect thickness of dermis by HE stain, content of hydroxyproline (Hyp) by chemical colorimetry, and serum MMP-1 and TIMP-1 content by ELISA. In addition, matrix metalloproteinase-1 (MMP-1) mRNA and relative content of tissue inhibitor of metalloproteinase-1 (TIMP1) mRNA was analyzed with Real-time PCR.

RESULTCompared with the model group, the LP-H group could significantly increase the thickness of dermis, skin Hyp content and serum TIMP-1 level, and decrease relative content of MMP-1 mRNA in skin and MMP-1 content in serum.

CONCLUSIONLP can regulate the metabolism of collagen photoaging skins by adjusting the activity of matrix metalloproteinase.

Animals ; Female ; Glucans ; Matrix Metalloproteinase 13 ; biosynthesis ; genetics ; metabolism ; Mice ; Plant Extracts ; chemistry ; pharmacology ; Plants, Medicinal ; chemistry ; Polysaccharides ; chemistry ; pharmacology ; RNA, Messenger ; genetics ; metabolism ; Skin Aging ; drug effects ; physiology ; radiation effects ; Tissue Inhibitor of Metalloproteinase-1 ; biosynthesis ; genetics ; metabolism ; Ultraviolet Rays