Endometrial Receptivity Analysis - a tool to increase an implantation rate in assisted reproduction.

INTRODUCTION: A successful embryo implantation is crucial for a positive outcome of in vitro fertilization. But there is only a short period during which the endometrium is receptive for embryo, this so called implantation window can be detected by a molecular diagnostic method endometrial receptivity analysis (ERA). OBJECTIVE: To find out the percentage of patients with a non-receptive endometrium in the time of ERA and to learn what part of them got pregnant after the identification of their personalized implantation window. DESIGN: A retrospective study. SETTING: REPROMEDA Biology Park, Centre of Reproductive Medicine and Preimplantation Genetic Diagnosis, Brno. METHODS: A cohort of 85 patients undergoing ERA from August 2015 to October 2018 was studied. 74 patients experienced a previous implantation failure, the average number of preceding unsuccessful frozen embryo transfers was 2,5 in this group, 11 women went through ERA due to the preventive reason before the first FET. In all women one euploid embryo was transferred. 48 patients were prepared either for ERA or FET in a natural menstrual cycle, 37 women in HRT cycle. We were interested in a percentage of non-receptive patients in the time of ERA and wanted to discover what part of non-receptive women got pregnant after the identification of their personal implantation window. The average number of frozen embryo transfers needed to achieve the pregnancy was also calculated. RESULTS: 31 of 85 patients (36.5%) were found to have a non-receptive endometrium. In the natural cycle 13 of 48 (27.1%) were non-receptive: five were pre-receptive, three early receptive, two late receptive and three post-receptive. In the HRT cycle 18 of 37 patients (48.6%) were non-receptive: 12 were pre-receptive, four early receptive, one late receptive, one post-receptive. Personalized FET was done in 26 of total 31 initially non-receptive patients, 18 of them got pregnant (69.2%). In the natural cycle 6 of 11 (54.5%) achieved the pregnancy, in the HRT cycle 12 of 15 women (80.0%) got pregnant. To achieve the clinical pregnancy 1.5 frozen embryo transfer in average was needed. CONCLUSION: A displaced implantation window was found in more than 1/3 of patients undergoing an assisted reproductive treatment. After the personalized FET the clinical pregnancy was noticed in 69.2% of them. This result supports an individual approach to patients in IVF programme besides other at the timing of embryo transfer after the identification of pWOI.

Post fire organic matter biodegradation in permafrost soils: Case study after experimental heating of mineral horizons.

Periodical ground fires of high frequency in permafrost forest ecosystems of Siberia (Russian Federation) are essential factors determining quantitative and qualitative parameters of permafrost soil organic matter. Specific changes in physical and chemical parameters and microbial activity of permafrost soil mineral horizons of northern taiga larch stands were revealed after heating at high temperatures (150-500°C) used for imitation of different burn intensities. Burning at 150-200°C resulted in decreasing of soil pH, whilst heating at 300-500°C caused increase of pH compare to unheated soils. Water-soluble organic carbon concentration in permafrost soils heated at 150-200°C was much higher than that of unheated soils. All these changes determined soil microbial activity in heated soils. In particular, in soils heated at 300-500°C there was momentary stimulating effect on substrate-induced respiration registered and on basal respiration values in soils burned at 150°C and 300-400°C. Four-month laboratory incubation of permafrost soils heated at different temperatures showed stimulation of microbial activity in first several days after inoculation due to high substrate availability after heating. Then soon after that soil microbial community started to be depleted on substrate because of decreasing water-soluble organic carbon, C and N content and it continued to the end of incubation.

[Postfire restoration of organic substance in the ground cover of the larch forests in the permafrost zone of central Evenkia].

The role of ground fires in transformation of organic substances in the ground cover of larch stands in the permafrost zone of Central Siberia was studied, as was the postfire restoration dynamics of organic substances. Ground fires lead to a considerable decrease in concentrations and resources of organic carbon and its individual fractions in the ground cover, and restoration takes many decades.