Fresh versus elective frozen embryo transfer: Cumulative live birth rates of 7,236 IVF cycles.

OBJECTIVE: To determine whether elective frozen embryo transfer (eFET), or the 'freeze-all' strategy, associated with better cumulative clinical outcomes compared with fresh embryo transfer (ET). METHODS: A total of 7,236 IVF cycles that were followed by a fresh ET or eFET between 2013 and 2017. The patients were subjected to controlled ovarian stimulation (COS) with a gonadotropin-releasing hormone (GnRH) antagonist protocol and cleavage-stage ET. Embryo cryopreservation was performed on day 3 by vitrification using an open system. A comparison of cumulative outcomes between the eFET (n=4,065cycles) and the fresh ET groups (n=3,171cycles) were performed. The analysis was performed in four groups of patients based on the number of retrieved oocytes: Group 1: poor responders (1-3 oocytes); Group 2: suboptimal responders (4-9 oocytes); Group 3: normal responders (10-15 oocytes); and Group 4: hyper-responders (>15 oocytes). The primary outcome was the cumulative live birth rate (CLBR) per stimulated cycle. RESULTS: There were a total of 10,283 ETs (n=5,639 eFET group; n=4,644 fresh group). The freeze-all strategy is associated with improved CLBRs in normal and hyper-responders, but not in suboptimal and poor responders. In Group 1, there were 351 IVF cycles and 387 ETs in total, and the CLBR was 14.3% and 17.7% (p=0.584) for the eFET and fresh group, respectively. In Group 2, there were 2,074 IVF cycles and 2,465 ET in total, and the CLBR was 25.1% and 23.3% (p=0.083) in the eFET and fresh group, respectively. There was a significant difference in the CLBR in Groups 3 and 4, favouring the eFET strategy. In Group 3, 2226 IVF cycles and 3243 ET were performed. The CLBR was 40.5% in the eFET and 36.6% in the fresh group (p<0.001). In Group 4, there were 2547 IVF cycles and 3,188 ET in total, and the CLBR was 52.2% and 47.7% (p<0.001) in the eFET and fresh group, respectively. The number needed to treat to achieve one additional live birth was 25.9 in Group 3 and 22.3 in Group 4. CONCLUSIONS: The implementation of the freeze-all strategy should be individualized. The freeze-all strategy is associated with improved CLBRs in normal and hyper-responders, but not in suboptimal and poor responders.

The changing of gelatin properties from tra catfish skin (Pangasianodon hypophthalmus) by alkaline replacement to enzyme in pretreated process / Alterações das propriedades da gelatina da pele do bagre tra (Pangasianodon hypophthalmus) pela substituição alcalina por enzima no processo pré-tratado

The effect of pretreated method to remove the non-collagenous protein by using alkaline and enzyme Alcalase, as well as the temperature and time for extracting on the properties of gelatin from tra catfish skin were investigated. Yields of gelatin extracted at 70 °C for 1h from pretreated skin by enzyme method (16.2%) was significantly higher than that of the sample by alkaline method (12.14%). However, the gel strength of gelatin from skin treated via enzyme Alcalase was lower than gelatin sample pretreated by alkaline while the turbidity values was higher than gelatin from skin pretreated via alkaline. From SDS-PAGE profile, gelatin from skin pretreated by alkaline consisted of two different α- chains in protein pattern while enzymatic gelatin had low molecular weight peptides. The FT-IR spectra showed the lower wavenumber in amide I and III of enzymatic gelatin in compare to alkaline gelatin by the loss of triple helical structure during enzyme treatment. From the results, the using enzyme for pretreated material has potential to replace the alkaline method for gelatin production with purpose to reduce chemical waste caused serious ecological issues.

Investigou-se o efeito do método pré-tratado para remoção da proteína não colágena com a utilização da alcalina e da enzima Alcalase, bem como a temperatura e o tempo de extração sobre as propriedades da gelatina da pele do bagre tra. O rendimento da gelatina extraída a 70 °C por 1h da pele pré-tratada pelo método enzimático (16,2%) foi significativamente superior ao da amostra pelo método alcalino (12,14%). No entanto, a força do gel da gelatina da pele tratada com a enzima Alcalase foi menor do que a amostra de gelatina pré-tratada com alcalina, enquanto os valores de turbidez foram maiores do que a gelatina da pele pré-tratada com alcalina. A partir do perfil SDS-PAGE, a gelatina da pele pré-tratada com alcalina consistia em duas cadeias α diferentes no padrão de proteína, enquanto a gelatina enzimática tinha peptídeos de baixo peso molecular. Os espectros de FT-IR mostraram o menor número de onda na amida I e III da gelatina enzimática em comparação com a gelatina alcalina pela perda da estrutura helicoidal tripla durante o tratamento enzimático. Pelos resultados obtidos, a utilização de enzimas para material pré-tratado tem potencial para substituir o método alcalino para produção de gelatina com objetivo de reduzir o desperdício químico causado por sérios problemas ecológicos.