Comparative Effectiveness of Mild or Conventional GnRH-Antagonist Protocols for Ovarian Stimulation in Poor Responders (Poseidon Group 4).

Background and Aims: A panel of experts (the Poseidon Group) introduced a new and more detailed stratification for poor ovarian responders in order to predict the prognosis of IVF outcome according to the sensitivity to FSH. However, various arguments about the management strategy of these patients still remain, including the convenience and the cost. Therefore, this study was conducted to compare the efficacy of mild and conventional GnRH antagonist ovarian stimulation prescribed in patients classified in Poseidon Group 4. Methods: This retrospective cohort study included 359 poor responder patients (Poseidon Group 4) treated with mild or conventional GnRH antagonist stimulation regimens from 8/2017 to 7/2019 at Tam Anh Hospital ART Center. The main outcomes were the index of Follicular Output Rate (FORT) or Follicle to Oocyte Index (FOI), the number of day-2 embryos and top-quality embryos obtained. The t-test and Mann-Whitney U test in SPSS v25.0 was used to analyze the continuous data and Chi-squared/Exact test was used for binary variables. Multiple linear regression analysis was done by using Stata versions 15.0 to measure association between primary endpoints with stimulation regimen controlled for covariates and possible confounding factors. Results: In the overall group of poor responders, the conventional GnRH antagonist protocol performed better than the mild protocol. Subsequently, data were analyzed according to the AFC. In women with AFC < 3, no significant differences were observed between the 2 regimens regarding FORT (p = 0.71), FOI (p = 0.12), the number of day-2-embryos (p = 0.052) and the number of top-quality embryos (p = 0.26). In contrast, in women with AFC ≥ 3, mild stimulation regimen resulted in significantly poorer outcome compared to the conventional GnRH antagonist regimen, regarding FORT (p < 0.01), FOI (p < 0.01), the number of day-2-embryos (p < 0.01) and top-quality embryos (p = 0.01). Conclusions: Considering poor responders classified in Poseidon Group 4, both ovarian stimulation regimens resulted in similar outcome for patients with a very low ovarian reserve (AFC < 3). In contrast, the GnRH conventional antagonist protocol with maximum initial FSH dose (300-375 IU/day) and supplementary LH (75-150 IU/day) was more effective than the mild one for patients whose ovarian reserve was less reduced. The Clinical Trial was approved by the Ethnical Biomedical Research Committee Tam Anh General Hospital.

Proteomic analysis of the peritrophic matrix from the gut of the caterpillar, Helicoverpa armigera.

The peritrophic matrix from the midgut of the caterpillar, Helicovera armigera, was solubilized by treatment with anhydrous trifluoromethanesulfonic acid, apparently by depolymerisation of its chitin component. This allowed the efficient extraction of proteins in a technique that may be broadly applicable to the analysis of other structures containing chitin. Gel electrophoresis and mass spectrometry of tryptic peptides were used to identify the extracted proteins with gut-expressed cDNA sequences. The major proteins of this cohesive, digestion-resistant structure are chitin deacetylase-like and mucin-like proteins, the latter with multiple chitin-binding domains that may cross-link chitin fibrils to provide a barrier against abrasive food particles and parasites, one of the major functions of the matrix. Other proteins found in the H. armigera gut peritrophic matrix suggest that the matrix is a dynamic, complex structure that may participate in the immobilization of digestive enzymes, actively protect the gut from parasite invasion and intercept toxins such as lectins and Bacillus thuringiensis crystal proteins.

A novel secreted protein toxin from the insect pathogenic bacterium Xenorhabdus nematophila.

The bacterium Xenorhabdus nematophila is an insect pathogen that produces several proteins that enable it to kill insects. Screening of a cosmid library constructed from X. nematophila strain A24 identified a gene that encoded a novel protein that was toxic to insects. The 42-kDa protein encoded by the toxin gene was expressed and purified from a recombinant system, and was shown to kill the larvae of insects such as Galleria mellonella and Helicoverpa armigera when injected at doses of around 30-40 ng/g larvae. Sequencing and bioinformatic analysis suggested that the toxin was a novel protein, and that it was likely to be part of a genomic island involved in pathogenicity. When the native bacteria were grown under laboratory conditions, a soluble form of the 42-kDa toxin was secreted only by bacteria in the phase II state. Preliminary histological analysis of larvae injected with recombinant protein suggested that the toxin primarily acted on the midgut of the insect. Finally, some of the common strategies used by the bacterial pathogens of insects, animals, and plants are discussed.