Opinion - Endometrial receptivity

Embryo implantation depends on the quality of the ovum and endometrial receptivity. Endometrial receptivity is a temporally unique sequence of factors that make the endometrium receptive to embryonic implantation. Implantation window is a period during which the endometrium is optimally receptive to implanting blastocyst (D6-10 postovulation). No conclusive evidence of age related histological changes in the endometrium. The biochemical markers of endometrial receptivity include endometrial adhesion molecules (e.g. integrins), endometrial anti-adhesion molecules (e.g. mucin 1), endometrial cytokines, endometrial growth factors, endometrial immune markers and other endometrial markers. Integrins are the best markers of endometrial receptivity. Most interest has been focused on the av β 3 integrin since it appears in endometrial glands and luminal surface on D20-21. Endometrial function test may be the most efficient way to directly assess endometrial receptivity prior to undergoing expensive ART procedures as it can identify unreceptive endometrium. Pinopodes, are morphological markers of endometrial receptivity, which persist for 24 to 48 hours between days 19 and 21 of the cycle. Non invasive assessment of endometrial receptivity includes, high resolution transvaginal ultrasonography (US), three-dimensional US, Doppler US, three-dimensional power Doppler US, magnetic resonance imaging and endometrial tissue blood flow. Four strategies for improving endometrial receptivity: to develop ovarian stimulation protocols that cause a minimum reduction in endometrial receptivity or may even increase it; to avoid the endometrium during stimulated cycles, to improve uterine vascularization and to treat the pathology

Covalent immobilization of microbial naringinase using novel thermally stable biopolymer for hydrolysis of naringin

Naringinase induced from the fermented broth of marine-derived fungus Aspergillus niger was immobilized into grafted gel beads, to obtain biocatalytically active beads. The support for enzyme immobilization was characterized by ART-FTIR and TGA techniques. TGA revealed a significant improvement in the grafted gel’s thermal stability from 200 to 300 °C. Optimization of the enzyme loading capacity increased gradually by 28-fold from 32 U/g gel to 899 U/g gel beads, retaining 99 % of the enzyme immobilization efficiency and 88 % of the immobilization yield. The immobilization process highly improved the enzyme’s thermal stability from 50 to 70 °C, which is favored in food industries, and reusability test retained 100 % of the immobilized enzyme activity after 20 cycles. These results are very useful on the marketing and industrial levels

Immobilized inulinase on grafted alginate beads prepared by the one-step and the two-steps methods

Grafted alginate beads were prepared using the Encapsulator by two methods, the one-step and the two-step. The methods of grafting were characterized by thermal gravimetric analysis and infrared (IR). The lass transition (Tg) of both grafted gel beads showed gradual thermal improvement over the control gel. However, the one-step method showed higher Tg (231 °C) compared to the two-step method (220 °C). Both methods were also evaluated for immobilization of an important industrial enzyme, inulinase, to produce fructose, which is good for diet regimens and suitable for diabetics. The one-step method showed an enzyme loading capacity (ELC) of 530 U/g gel beads compared to 336 U/g gel beads for the two-step method. Accordingly, the one-step method has been chosen for further optimization. The ELC has been optimized to reach 1627 U/g gel using our locally prepared crude enzyme compared to 10.9 U/g by another author using purified inulinase. The immobilization process improved as did the enzyme's thermal stability, from 50 to 60 °C, which is the most suitable temperature used in food industries to prevent microbial contamination. The enzyme's thermal stability test at 60 °C and for an incubation time of 2 h, revealed a drastic decrease of the free enzyme activity to 21%, compared to 89% retention of activity for the immobilized enzyme. The immobilization process improved as well the enzyme's shelf stability, where the free enzyme lost all of its activity at room temperature after 28 days, the immobilized enzyme retained over 77% of its initial activity. These results are encouraging to produce high fructose syrup on the industrial scale as the carrier is efficient and the method is simple and economic.?©?2010 American Chemical Society