Late Proterozoic rise in atmospheric oxygen concentration inferred from phylogenetic and sulphur-isotope studies

Nature ◽  
1996 ◽  
Vol 382 (6587) ◽  
pp. 127-132 ◽  
Author(s):  
Donald E. Canfield ◽  
Andreas Teske
Keyword(s):  
Oxygen Concentration ◽  
Atmospheric Oxygen ◽  
Sulphur Isotope ◽  
Late Proterozoic ◽  
Isotope Studies

scholarly journals The influence of oxygen concentration during embryo culture on obstetric and neonatal outcomes: a secondary analysis of a randomized controlled trial

2020 ◽  
Vol 35 (9) ◽  
pp. 2017-2025
Author(s):  
Maria Rendón Abad ◽  
Vicente Serra ◽  
Pilar Gámiz ◽  
José Maria de los Santos ◽  
Josè Remohí ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Embryo Culture ◽  
Atmospheric Oxygen ◽  
Controlled Trial ◽  
Secondary Analysis ◽  
Oocyte Donation ◽  
Neonatal Outcomes ◽  
Randomized Controlled ◽  
Day 3 Embryos ◽  
Day 3 Embryo

Abstract STUDY QUESTION Does oxygen concentration during 3-day embryo culture affect obstetric and neonatal outcomes? SUMMARY ANSWER Oxygen concentration during 3-day embryo culture does not seem to affect the obstetric and neonatal outcomes measured. WHAT IS KNOWN ALREADY Atmospheric oxygen appears to be harmful during extended embryo culture. Embryo culture conditions might therefore be a potential risk factor for subsequent fetal development and the health of future children. No data are available concerning the obstetrics and neonatal outcomes after Day 3 transfer of embryos cultured under reduced and atmospheric oxygen tensions. STUDY DESIGN, SIZE, DURATION A secondary analysis of a previous randomized controlled trial assessing clinical pregnancy outcomes was carried out. This analysis included 1125 consecutive oocyte donation cycles utilizing ICSI or IVF and Day 3 embryo transfers between November 2009 and April 2012. The whole cohort of donated oocytes from patients who agreed to participate in the study were randomly allocated (1:1 ratio) to a reduced O2 tension group (6% O2) or an air-exposed group (20% O2) based on a computer-generated randomization list. Fresh and vitrified oocytes were used for oocyte donation. Only those pregnancies with a live birth at or beyond 24 weeks of gestation were included. PARTICIPANTS/MATERIALS, SETTING, METHODS Day 3 embryos were cultured in an atmosphere of 5.5% CO2, 6% O2, 88.5% N2 versus a dual gas system in air. MAIN RESULTS AND THE ROLE OF CHANCE From the eligible 1125 cycles, 564 were allocated to the 6% O2 group and 561 cycles to the 20% O2 group. However, 50 and 62 cycles did not reach embryo transfer in the 6% and 20% O2 groups, respectively. No differences were found between 6% O2 and atmospheric O2 tension in the number of livebirths per embryo transfer (mean ± SD, 0.5 ± 0.7 versus 0.5 ± 0.7), pregnancy complications or neonatal outcomes. Both groups (6% and atmospheric O2) had similar single and twin delivery rates (40.8% versus 38.1% and 10.7% versus 12.3%, respectively). Preterm delivery rates and very preterm delivery rates (10.80% versus 13.24% and 1.25% versus 2.94%, respectively), birthweight (3229 ± 561 g versus 3154 ± 731 g), low birthweight (2.92% versus 2.45%), birth height (50.18 ± 2.41 cm versus 49.7 ± 3.59 cm), head circumference (34.16 ± 1.87 cm versus 33.09 ± 1.85 cm) and 1 min Apgar scores (8.96 ± 0.87 versus 8.89 ± 0.96) were also similar between 6% and atmospheric O2 groups, respectively. LIMITATIONS, REASONS FOR CAUTION The number of liveborns finally analyzed is still small and not all obstetric and neonatal variables could be evaluated. Furthermore, a small proportion of the obstetric and neonatal data was obtained through a questionnaire filled out by the patients themselves. One reason for the lack of effect of oxygen concentration on pregnancy outcome could be the absence of trophectoderm cells at cleavage stage, which may make Day 3 embryos less susceptible to hypoxic conditions. WIDER IMPLICATIONS OF THE FINDINGS Nowadays many IVF laboratories use a more physiological oxygen concentration for embryo culture. However, the benefits of using low oxygen concentration on both laboratory and clinical outcomes during embryo culture are still under debate. Furthermore, long-term studies investigating the effect of using atmospheric O2 are also needed. Gathering these type of clinical data is indeed, quite relevant from the safety perspective. The present data show that, at least in egg donation cycles undergoing Day 3 embryo transfers, culturing embryos under atmospheric oxygen concentration seems not to affect perinatal outcomes. STUDY FUNDING/COMPETING INTEREST(S) The present project was supported by the R + D program of the Regional Valencian Government, Spain (IMPIVA IMDTF/2011/214). The authors declare that they have no conflict of interest with respect to the content of this manuscript. TRIAL REGISTRATION NUMBER NCT 01532193.

scholarly journals Metabolic Activity of Human Embryos after Thawing Differs in Atmosphere with Different Oxygen Concentrations

2020 ◽  
Vol 9 (8) ◽  
pp. 2609
Author(s):  
Michal Ješeta ◽  
Andrea Celá ◽  
Jana Žáková ◽  
Aleš Mádr ◽  
Igor Crha ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Oxygen Concentration ◽  
Atmospheric Oxygen ◽  
Blastocyst Stage ◽  
Human Embryos ◽  
Total Amino Acid ◽  
Oxygen Levels ◽  
Amino Acid Turnover ◽  
Cultivation Environment

The vitrification of human embryos is more and more frequently being utilized as a method of assisted reproduction. For this technique, gentle treatment of the embryos after thawing is crucial. In this study, the balance of amino acids released to/consumed from the cultivation media surrounding the warmed embryos was observed in the context of a cultivation environment, which was with the atmospheric oxygen concentration ≈20% or with a regulated oxygen level—hysiological (5%). It is the first time that total amino acid turnover in human embryos after their freezing at post compaction stages has been evaluated. During this study, progressive embryos (developed to blastocyst stage) and stagnant embryos (without developmental progression) were analyzed. It was observed that the embryos cultivated in conditions of physiological oxygen levels (5% oxygen) showed a significantly lower consumption of amino acids from the cultivation media. Progressively developing embryos also had significantly lower total amino acid turnovers (consumption and production of amino acids) when cultured in conditions with physiological oxygen levels. Based on these results it seems that a cultivation environment with a reduced oxygen concentration decreases the risk of degenerative changes in the embryos after thawing. Therefore, the cultivation of thawed embryos in an environment with physiological oxygen levels may preclude embryonal stagnation, and can support the further development of human embryos after their thawing.

scholarly journals Evaluation of the quality of embryo based on morphology cultured at low oxygen concentration

2021 ◽  
Vol 63 (9) ◽  
pp. 22-25
Author(s):  
Linh Chi Nguyen ◽  
◽  
Thi Tuong Chau Ngo ◽  
Dinh Tao Nguyen ◽  
Ngoc Diep Nguyen ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Atmospheric Oxygen ◽  
Poor Quality ◽  
Embryo Morphology ◽  
Low Oxygen ◽  
Average Quality ◽  
Fertilisation Rate ◽  
Group 2 ◽  
Low Oxygen Concentration

Objectives: evaluating the quality of embryo morphology cultured at low oxygen concentration (5%) at different stages of embryonic development: day 3, day 5. Methods: the present study examined 168 IVF/ICSI cycles from October 2019 to February 2021 at the Assisted Reproductive Center, 16A Ha Dong General Hospital. Embryos were randomly assigned to 2 groups: group 1 used a K-system G-210 tri-gas incubator (Australia) (5% O2, 5% CO2, 90% N2) while group 2 used a Thermo Scientific 371 dual-gas incubator (Denmark) (5% CO2, 75% N2 with 20% atmospheric Oxygen concentration). Participants in the study were patients younger than 37 years old, with AMH>1.2 ng/ml, and AFC≥4. Mature oocytes were injected with sperm, and cultured in a sequential medium (G1,G2-PLUSTM). Embryologists assessed embryos on the day of fertilisation, days 3, 5, and compared the results of the two groups, using the method of descriptive statistics and T-test. The results revealed an insignificant difference in fertilisation rate and the quality of cleavages cultured in these 2 groups (percentages of good- and average quality cleavages were, in turn, 77.28±4.62% và 77.99±5.03%, at p>0.05, number of poor quality cleavages were, in turn, 1.71±0.38 vs 1.97±0.49 with p>0.05). The results on day 5 embryo showed that the percentage of blastocysts (from fertilisation) and the percentage of morphologically good- and average-quality blastocysts tended to increase higher when cultured in 5% oxygen concentration (p<0.05) compared with the 20% one (57.79±3.60% and 53.05±4.50%, 78.62±4.42% and 70.97±5.67%, respectively). Conclusions: embryo cultured in a low oxygen concentration helps embryos develop better on day 5 than when cultured at atmospheric concentrations

scholarly journals Effect of Atmospheric Oxygen Concentration on Germination of Three Species of Weedy Morningglory Using a Glass Vessel for Gas Replacement

2014 ◽  
Vol 83 (2) ◽  
pp. 160-164
Author(s):  
Sohei Asakura ◽  
Atsushi Matsumura ◽  
Yoshihiro Imahori ◽  
Hiroyuki Daimon
Keyword(s):  
Oxygen Concentration ◽  
Atmospheric Oxygen ◽  
Glass Vessel

Effects of Hypoxia on Differentiation of Mesenchymal Stem Cells

2020 ◽  
Vol 15 (4) ◽  
pp. 332-339
Author(s):  
Wei Chen ◽  
Yi Zhuo ◽  
Da Duan ◽  
Ming Lu
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Oxygen Concentration ◽  
Atmospheric Oxygen ◽  
Physiological State ◽  
The Body ◽  
Alveolar Epithelial Cells ◽  
Differentiation Potential ◽  
Alveolar Epithelial

Mesenchymal Stem Cells (MSCs) are distributed in many parts of the human body, including the bone marrow, placenta, umbilical cord, fat, and nasal mucosa. One of the unique features of MSCs is their multidirectional differentiation potential, including the ability to undergo osteogenesis, adipogenesis, and chondrogenesis, and to produce neurons, endothelial cells, Schwann cells, medullary nucleus cells, cardiomyocytes, and alveolar epithelial cells. MSCs have thus become a hot research topic in recent years. Numerous studies have investigated the differentiation of MSCs into various types of cells in vitro and their application to numerous fields. However, most studies have cultured MSCs under atmospheric oxygen tension with an oxygen concentration of 21%, which does not reflect a normal physiological state, given that the oxygen concentration generally used in vitro is four to ten times that to which MSCs would be exposed in the body. We therefore review the growing number of studies exploring the effect of hypoxic preconditioning on the differentiation of MSCs.

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