89 IMPROVED POST-WARMING DEVELOPMENTAL COMPETENCE OF OPEN PULLED STRAW-VITRIFIED <i>IN VITRO</i> -PRODUCED BOVINE BLASTOCYSTS BY SUBLETHAL HYDROSTATIC PRESSURE PRETREATMENT
Bibliographic record
Abstract
Vitrification of in vitro (IVP)-produced bovine blastocysts is well established, reaching post-warming hatching rates close to 70–80% in vitro . Nevertheless, improvements still are needed regarding realizable pregnancy rates. High hydrostatic pressure (HHP) treatment of fresh boar semen before freezing increased the litter size achieved by insemination of frozen–thawed boar semen (Kuo et al . 2007 6th Int. Conf. Boar Semen Pres, Alliston, ON, Canada, poster #22); HHP treatment-related improvements were also observed in the in vitro cryosurvival of mouse blastocysts (Pribenszky et al . 2004 Reprod. Fertil. Dev. 17, 199–200), bull and boar semen, and pig oocytes, theoretically by the sublethal stress-induced production/stabilization of shock proteins (Pribenszky et al . 2006 Reprod. Fertil. Dev. 18, 162–163; 2007 Reprod. Fertil. Dev. 19, 181–182; and b; Du et al . 2007). The aim of the present study was to improve the post-warming in vitro developmental competence of vitrified bovine IVP blastocysts through the application of HHP as pre-treatment, in order to apply the protocol in later in vivo experiments. Day 7 IVP blastocysts were aspirated in TQC holding medium (AB Technology, Sao Paulo, Brazil) into 0.25-mL straws. Straws were pressure-treated in a custom-made hydrostatic pressure chamber (Cryo-Innovation Ltd., Budapest, Hungary), using water as pressure medium. Six hundred bar pressure was applied for 60 min at 32°C. Immediately after pressure treatment, or following 60- or 120-min incubation, embryos were vitrified and warmed using open pulled straws (OPS) according to the method of Vajta et al . (1998 Mol. Reprod. Dev. 51, 53–58). Untreated blastocysts were vitrified as controls. After warming, embryos were cultured in vitro in SOF (Holm et al . 1999 Theriogenology 52, 683–700) for 72 h. Embryos were checked for re-expansion and hatching at 4, 24, 48, and 72 h post-warming. For the experiment, 404 blastocysts were used in 5 replicates. Logistic regression was used for statistical evaluation. All vitrified groups were inferior compared to the non-vitrified control (97%, 97%, 98, and 100% expansion; 0%, 23%, 72 and 91% hatching at 4, 24, 48, and 72 h, respectively). HHP treatment had a significant effect ( P > 0.05) on the post-warming developmental competence of vitrified blastocysts. HHP treatment followed by 60 min of equilibration proved to be superior among all treatment groups regarding both re-expansion and hatching rates and the speed of resumption of normal in vitro development (HHP treatment followed by a 60-min equilibration time before vitrification/warming: re-expansion rates: 88%, 89%, 85, and 90%; hatching rates: 0%, 22%, 51, and 73% v . non-treated vitrified/warmed controls: re-expansion rates: 63%, 69%, 71, and 81%; hatching rates: 0%, 6%, 43, and 63%; at 4, 24, 48, and 72 h post-warm, respectively). In conclusion, hydrostatic pressure pre-treatment significantly improved in vitro survival and hatching rates as well as the speed of resumption of normal in vitro development. Further studies are needed to reveal the molecular-biological implications of the HHP treatments, as well as field trials to test if the in vitro improvements can be confirmed by pregnancy and birth rates. This work was supported by EMBRAPA and a Kozma grant, Hungary .
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".