scholarly journals Optimization of the balance between effort and yield in unilateral surgical transfer of mouse embryos

2017 ◽  
Vol 51 (6) ◽  
pp. 622-628 ◽  
Author(s):  
Pablo González-Jara ◽  
Tomás Fontela ◽  
Esther López-Mimbela ◽  
Marta Cereceda ◽  
Daniel Del Olmo ◽  
...  
Keyword(s):  
Embryo Transfer ◽  
Mouse Embryos ◽  
Mouse Strains ◽  
Optimization Approach ◽  
Use Of Resources ◽  
Heterogeneous Nature ◽  
Laboratory Manuals ◽  
The Mean ◽  
Transfer Procedures

Surgical transfer of embryos is carried out daily in animal facilities worldwide for the rederivation of mouse strains/lines, among other purposes. Current protocols described in laboratory manuals recommend using a high number of embryos during transfer, typically in the range of 15 up to 25. To optimize the use of resources it is necessary to estimate and relate the effort required and the yield obtained. Here, we analyse the balance between the number of embryos transferred (the effort), and the yield as the number of born pups obtained from surgical embryo transfer. To accomplish this, we have analyzed data obtained during rederivation of nearly one hundred lines of mice to a new animal facility. Our results confirm that the use of increasing numbers of embryos per transfer increases the yields of born pups, as has been described previously in the literature, but they also highlight the disproportionate effort required, i.e. in the number of embryos that needed to be transferred. An estimate of the mean expected yields of surgical transfers and their comparison with the actual observed yields indicated that the balance between effort and yield is optimized when using lower numbers of embryos than in currently used protocols, in the range of 8 to 12. Given the heterogeneous nature of the data presented and analyzed here, which is from a population of mice that may be considered as representative of any animal facility, our optimization approach should help save resources in similar facilities and improve the yields of embryo transfer procedures.

scholarly journals Modeling the Excess Velocity of Low-Viscous Taylor Droplets in Square Microchannels

Fluids ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 162 ◽  
Author(s):  
Thorben Helmers ◽  
Philip Kemper ◽  
Jorg Thöming ◽  
Ulrich Mießner
Keyword(s):  
High Speed ◽  
Process Intensification ◽  
Continuous Phase ◽  
Channel Cross Section ◽  
Optimization Approach ◽  
Mean Flow ◽  
Bypass Flow ◽  
Wall Film ◽  
Proposed Model ◽  
The Mean

Microscopic multiphase flows have gained broad interest due to their capability to transfer processes into new operational windows and achieving significant process intensification. However, the hydrodynamic behavior of Taylor droplets is not yet entirely understood. In this work, we introduce a model to determine the excess velocity of Taylor droplets in square microchannels. This velocity difference between the droplet and the total superficial velocity of the flow has a direct influence on the droplet residence time and is linked to the pressure drop. Since the droplet does not occupy the entire channel cross-section, it enables the continuous phase to bypass the droplet through the corners. A consideration of the continuity equation generally relates the excess velocity to the mean flow velocity. We base the quantification of the bypass flow on a correlation for the droplet cap deformation from its static shape. The cap deformation reveals the forces of the flowing liquids exerted onto the interface and allows estimating the local driving pressure gradient for the bypass flow. The characterizing parameters are identified as the bypass length, the wall film thickness, the viscosity ratio between both phases and the C a number. The proposed model is adapted with a stochastic, metaheuristic optimization approach based on genetic algorithms. In addition, our model was successfully verified with high-speed camera measurements and published empirical data.

scholarly journals Genetic Control of Mammalian Meiotic Recombination. I. Variation in Exchange Frequencies Among Males From Inbred Mouse Strains

Genetics ◽  
2002 ◽  
Vol 162 (1) ◽  
pp. 297-306 ◽  
Author(s):  
Kara E Koehler ◽  
Jonathan P Cherry ◽  
Audrey Lynn ◽  
Patricia A Hunt ◽  
Terry J Hassold
Keyword(s):  
Meiotic Recombination ◽  
Inbred Mouse ◽  
Inbred Strains ◽  
Male Meiosis ◽  
Mouse Strains ◽  
Recombination Rates ◽  
The Mean ◽  
Genetic Background Effects ◽  
Exchange Patterns ◽  
Positive Interference

AbstractGenetic background effects on the frequency of meiotic recombination have long been suspected in mice but never demonstrated in a systematic manner, especially in inbred strains. We used a recently described immunostaining technique to assess meiotic exchange patterns in male mice. We found that among four different inbred strains—CAST/Ei, A/J, C57BL/6, and SPRET/Ei—the mean number of meiotic exchanges per cell and, thus, the recombination rates in these genetic backgrounds were significantly different. These frequencies ranged from a low of 21.5 exchanges in CAST/Ei to a high of 24.9 in SPRET/Ei. We also found that, as expected, these crossover events were nonrandomly distributed and displayed positive interference. However, we found no evidence for significant differences in the patterns of crossover positioning between strains with different exchange frequencies. From our observations of >10,000 autosomal synaptonemal complexes, we conclude that achiasmate bivalents arise in the male mouse at a frequency of 0.1%. Thus, special mechanisms that segregate achiasmate chromosomes are unlikely to be an important component of mammalian male meiosis.

P–667 Dydrogesterone supplementation in cycles triggered with lone GnRH agonist for final oocyte maturation resulted in an acceptable pregnancy rate

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
M Safrai ◽  
S Hertsberg ◽  
A Be Meir ◽  
B Reubinoff ◽  
T Imbar ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Gnrh Agonist ◽  
Luteal Phase ◽  
Fresh Embryo Transfer ◽  
Luteal Support ◽  
Luteal Phase Support ◽  
Gnrh Agonist Trigger ◽  
The Mean ◽  
Agonist Trigger

Abstract Study question Can luteal oral Dydrogesterone (Duphaston) supplementation in an antagonist cycle after a lone GnRH agonist trigger rescue the luteal phase, allowing the possibility to peruse with fresh embryo transfer? Summary answer Functionality of the luteal phase in an antagonist cycle after a lone GnRH agonist trigger can be restored by adding Duphaston to conventional luteal support. What is known already Ovarian hyperstimulation syndrome (OHSS) is dramatically reduced when using antagonist cycle with lone GnRH agonist trigger before ovum pick up. This trigger induces short luteinizing hormone (LH) and follicle-stimulating hormone (FSH) peaks, associated with reduced progesterone and estrogen levels during the luteal phase. They cause an inadequate luteal phase and a significantly reduced implantation rate leading to a freeze all practice in those cycles. Study design, size, duration A retrospective cohort study. The study group (n = 123) included women that underwent in vitro fertilization cycles from January 2017 to May 2020. Patients received a GnRH-antagonist with a lone GnRH-agonist trigger due to imminent OSHH. The control group (n = 374) included patients under 35 years old that, during the same time period, underwent a standard antagonist protocol with a dual trigger of a GnRH-agonist and hCG. Participants/materials, setting, methods Study patients were given Dydrogesterone (Duphaston) in addition to micronized progesterone vaginal pills (Utrogestan) for luteal support (Duphaston group). Controls were treated conventionally with Utrogestan for luteal phase support (hCG group). The outcomes measured were pregnancy rate and OHSS events. Main results and the role of chance Our study was the first to evaluate the addition of Duphaston to standard luteal phase support in an antagonist cycle triggered by a lone GnRH agonist before a fresh embryo transfer. The mean number of oocytes retrieved and estradiol plasma levels were significantly higher in the Duphaston group than in the hCG group (16.9 ±7.7 vs. 10.8 ± 5.3 and 11658 ± 5280 pmol/L vs. 6048 ± 3059 pmol/L, respectively). The fertilization rate was comparable between the two groups. The mean number of embryos transferred and the clinical pregnancy rate were also comparable between groups (1.5 ± 0.6 vs 1.5 ± 0.5 and 46.3% vs 40.9%, respectively). No OHSS event was reported in either group. Limitations, reasons for caution This retrospective study may carry an inherent selection and information bias, derived from medical record coding. An additional limitation was the choice of physician for the lone GnRH trigger, which may have introduced a selection bias and another potential caveat was the relatively small sample size of our study groups. Wider implications of the findings: The addition of Duphaston to conventional luteal support could effectively salvage the luteal phase without increasing the risk for OHSS. This enables, to peruse in those cycle, with fresh embryo transfer, avoiding the need to freeze all the embryos and postponed embryo transfer. Leading to lower psychological burden and costs. Trial registration number 0632–20-HMO

Diploid and haploid mouse parthenogenetic development following in vitro activation and embryo transfer

Development ◽  
1974 ◽  
Vol 31 (3) ◽  
pp. 635-642
Author(s):  
M. H. Kaufman ◽  
R. L. Gardner
Keyword(s):  
Embryo Transfer ◽  
Mouse Embryos ◽  
Parthenogenetic Development ◽  
In Vitro Activation ◽  
Haploid Embryos ◽  
Parthenogenetic Mouse Embryos

Parthenogenetic mouse embryos were selected following in vitro activation, and transferred to the oviducts of pseudopregnant recipients. Decidua was evoked by 50–56% of diploid parthenogenones compared to 35·1% of haploid embryos with a single pronucleus, 37·5% of immediate cleavage eggs and 77% of fertilized eggs (controls). On day 4, 58·7% of diploid parthenogenones were morphologically normal morulae or blastocysts; over 90% of these ‘normal’ embryos evoked decidua when retransferred to recipients compared to 8·9% of abnormal embryos flushed from the ‘transfer’ sides, suggesting that only ‘normal’ embryos could evoke decidua. Potentially diploid parthenogenones remained diploid on chromosomal examination on day 4.

scholarly journals Electrical Behaviour of Finely Divided Ice

1978 ◽  
Vol 21 (85) ◽  
pp. 173-191 ◽  
Author(s):  
J. G. Paren ◽  
J. W. Glen
Keyword(s):  
Relaxation Times ◽  
Surface Adsorption ◽  
Frequency Dispersion ◽  
Polar Regions ◽  
Electrical Behaviour ◽  
Heterogeneous Nature ◽  
Glacier Ice ◽  
Bulk Relaxation ◽  
Adsorption Of Co ◽  
The Mean

Abstract The electrical behaviour of ice which has been finely ground and compressed was investigated during ageing in air and over a range of temperatures. The dielectric behaviour may be accurately represented as the sum of two elliptical relaxation spectra. The behaviour eventually stabilizes with similar activation energies for the mean relaxation time of each spectrum c. 0.25 eV, and the ratio of the relaxation times is ten in samples of density c. 0.42 Mg m-3. Arguments are presented on whether the higher-frequency dispersion is a consequence of the heterogeneous nature of the samples or is a bulk relaxation process. The similarities between the behaviour of such finely ground ice and of deposited snow and polar glacier ice are discussed. The extent to which the results may be attributed to surface adsorption of CO2 are examined by reference to measurements of the CO2 content of finely divided ice and ice from polar regions.

Transcortin and vitamin D-binding protein levels in mouse serum

1986 ◽  
Vol 109 (2) ◽  
pp. 141-147 ◽  
Author(s):  
D. Faict ◽  
P. De Moor ◽  
R. Bouillon ◽  
W. Heyns ◽  
H.-J. Heiniger ◽  
...  
Keyword(s):  
Vitamin D ◽  
Sex Difference ◽  
Binding Protein ◽  
Strain Difference ◽  
Mouse Strains ◽  
Mouse Serum ◽  
Adult Males ◽  
Vitamin D Binding Protein ◽  
Protein Levels ◽  
The Mean

ABSTRACT The influence of age, sex and strain on the serum concentration of transcortin (corticosteroid-binding globulin) and vitamin D-binding protein (DBP) in mice was investigated. The effect of age was studied in two strains, C57BL/6JPfd and BALB/cmHeAPfd. The concentration of transcortin and DBP increased with age. In young animals the concentration of each protein showed a significant strain difference, which disappeared in older mice for DBP, but not for transcortin. In 7-day-old animals, no sex difference was observed for either protein, but in older animals a clear sex difference was found for transcortin. Adult males tended to have somewhat higher levels of DBP than adult females, but this difference was significant only on day 70. The variation in transcortin and DBP levels was further investigated in a large number of mouse strains. The DBP concentration did not markedly vary among strains (5·98–9·65 μmol/l in males and 5·08–8·85 μmol/l in females). Transcortin, however, showed marked strain variations, ranging from 0·72 to 2·06 μmol/l in males and from 1·02 to 4·55 μmol/l in females and there was a significant correlation (r= 0·66, n= 26, P<0·001) between the mean transcortin levels in males and females of different strains. Interstrain variation was much higher than intrastrain variation or variation among related strains, suggesting that the transcortin concentration is largely controlled by genetically determined factors. There was a significant correlation (r= 0·82, n = 9, P<0·01) between the mean corticosterone and transcortin concentrations (measured at 21.00 h). Consequently, differences in the free corticosterone levels in the serum of various mouse strains were smaller than the differences in the total corticosterone concentrations. The affinity of transcortin for corticosterone was similar in all but one strain; however, transcortin of the RIIIS/J strain showed a lower affinity for corticosterone. J. Endocr. (1986) 109, 141–147

109 RELATIONSHIP BETWEEN ULTRASONIC MORPHOLOGY OF CORPUS LUTEUM IN HOLSTEIN HEIFERS AND PREGNANCY RATE AFTER EMBRYO TRANSFER

2012 ◽  
Vol 24 (1) ◽  
pp. 167
Author(s):  
A. Shirasawa ◽  
Y. Nakamura ◽  
A. Ideta ◽  
Y. Oono ◽  
M. Urakawa ◽  
...  
Keyword(s):  
Corpus Luteum ◽  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Blood Clot ◽  
Pregnancy Rates ◽  
Bovine Embryo ◽  
Tissue Area ◽  
The Mean ◽  
Rectal Palpation ◽  
Experimental Group

Recipient animals for bovine embryo transfer (ET) are routinely selected according to the morphology of the corpus luteum (CL) estimated by rectal palpation. However, rectal palpation is not a precise method of diagnosing the functional status of a CL. Ovarian ultrasonography (US) may be used to improve such diagnoses. The aim of this study was to evaluate the relationship between ultrasonographic images of CL and pregnancy rates after ET in Holstein heifers to determine whether US can be used to select recipients for ET. Recipient heifers (n = 285) were selected by detection of natural oestrus or following oestrus synchronization using a progesterone-releasing intravaginal device (PRID; ASKA Pharmaceutical, Tokyo, Japan). Transrectal US was performed immediately before ET, on Days 6 to 8 of the oestrous cycle (oestrus = Day 0), using a B-mode scanner (HS1500V; Honda Electronics Co. LTD, Aichi, Japan) equipped with a 7.5-MHz linear-array transducer designed for intrarectal placement. A cross-sectional image of the maximal area of the CL and luteal cavity was obtained. The areas of the CL and luteal cavity were each calculated using the formula for the area of an ellipse (height/2 × width/2 × π). (1) Ultrasonic morphology of CL was classified into 3 types: without cavity (n = 128), with cavity (n = 145) and with blood clot (n = 12). (2) The luteal cavity was categorized into 3 groups: small (<100 mm2, n = 93), medium (100 ≤ x < 200 mm2, n = 32) and large (≥200 mm2, n = 20). (3) Luteinized tissue area (total area of CL minus the area of the luteal cavity) was categorized into 3 groups: small (<250 mm2, n = 61), medium (250 ≤ x < 350 mm2, n = 128) and large (≥350 mm2, n = 84). In vivo–produced embryos were transferred nonsurgically into the uterine horn ipsilateral to the CL. Pregnancy was determined by transrectal US on Days 30 to 40 of gestation. The pregnancy rates of each experimental group were analysed by logistic regression. In this study, the pregnancy rate did not differ significantly in each experimental group: (1) without cavity: 77.3% (99/128), with cavity: 75.2% (109/145) and blood clot: 75.0% (9/12); (2) small cavity: 73.1% (68/93), medium: 75.0% (24/32) and large: 85.0% (17/20). The mean area of the cavity was 100.8 ± 110.3 mm2 (mean ± standard deviation) and recipients with 0 to 539.7 mm2 sized cavities had successful pregnancies (observational range was 0 to 539.7 mm2). (3) The pregnancy rates of recipients that had small, medium and large luteinized tissue were 77.0% (47/61), 75.0% (96/128) and 77.4% (65/84), respectively. The mean area of luteinized tissue was 318.9 ± 90.3 mm2 and 155.0 to 620.0 mm2 sized luteinized tissue had pregnancy success (observational range was 132.8 to 620.0 mm2). In conclusion, the results from this study indicate that the presence of a luteal cavity or blood clot has no detrimental effect on pregnancy success after ET in Holstein heifers. Furthermore, no relationship was found between luteinized tissue area at the time of ET and pregnancy rate.

scholarly journals Procriação Medicamente Assistida em Ciclo Natural: Avaliação dos Resultados de um Departamento de Medicina da Reprodução

2019 ◽  
Vol 32 (1) ◽  
pp. 25
Author(s):  
Mariana Carlos Alves ◽  
Andreia Leitão Marques ◽  
Helena Barros Leite ◽  
Ana Paula Sousa ◽  
Teresa Almeida-Santos
Keyword(s):  
Embryo Transfer ◽  
Assisted Reproduction ◽  
Ovarian Stimulation ◽  
Lower Cost ◽  
Oocyte Retrieval ◽  
Clinical Pregnancy ◽  
Poor Responders ◽  
Natural Cycle ◽  
Medically Assisted Reproduction ◽  
The Mean

Introduction: Medically assisted reproduction in natural cycle has been investigated, especially in women with poor response to conventional ovarian stimulation, with endometrial receptivity improvement, lower cost and possibility of successive cycles. The disadvantages are: lower profitability per treatment cycle and higher cancellation rate. The aim of this study was to determine the rate of clinical pregnancy in infertile women subjected to medically assisted reproduction in natural cycle.Material and Methods: Retrospective study of 149 medically assisted reproduction without ovarian stimulation of 50 infertile women, between January/2011 and October/2014.Results: The mean age of women undergoing medically assisted reproduction in natural cycle was 36.1 years. Approximately half (46.0%) of the cycles were performed in poor responders. On the day of ovulation trigger, the mean diameter of the follicle was 17.5 mm. Twenty-three cycles (15.4%) were canceled prior to ovulation trigger. In 8 cycles (5.3%), ovulation occurred between ovulation trigger and oocyte retrieval. In the majority of cycles (n = 118; 79.2%) oocyte retrieval was executed, a medically assisted reproduction technique was performed in 71 (47.6%), mostly intracytoplasmic injection. The overall fertilization rate was 77.5%. In 40 cycles (26.8%) there was embryo transfer. The implantation rate and the clinical pregnancy rate by embryo transfer was 35.0% and 25.0%, respectively. Most pregnancies occurred in poor responders, according to Bologna criteria.Discussion: Although the pregnancy rate per cycle started was 6.7%, the rate of clinical pregnancy per embryo transfer is quite satisfactory, being a group of women with unfavorable responses in previous treatments. The relatively high rates of cycle cancellation are mitigated by the greater simplicity and lower cost of these cycles.Conclusion: The results obtained in this study demonstrate that Medically Assisted Reproduction in natural cycle may be an alternative treatment for ovarian stimulation in patients with poor prognosis, whose only alternative would be oocyte donation.

Laparoscopy for insemination, embryo recovery and embryo transfer in ewes

1986 ◽  
Vol 1986 ◽  
pp. 66-66
Author(s):  
W. A. C. McKelvey ◽  
J. J. Robinson ◽  
R. P. Aitken
Keyword(s):  
Embryo Transfer ◽  
Operative Time ◽  
Cattle Breeding ◽  
Genetic Traits ◽  
Embryo Recovery ◽  
Surgical Methods ◽  
Rapid Dissemination ◽  
Repeated Use ◽  
Transfer Procedures ◽  
Donor Cows

Embryo transfer has become a widely used technique for the more rapid dissemination of valuable genetic traits in cattle. The rapid uptake of embryo transfer technology by the cattle breeding industry has largely resulted from the development of non-surgical methods for the recovery of embryos from donor cows and for their subsequent implantation into recipient animals. These non-surgical methods not only reduce operative time but permit the repeated use of cows without the risk of formation of post-operative adhesions.Although embryo transfer is a technique commonly used by research workers in the study of certain aspects of reproductive physiology in sheep, there are several problems associated with conventional transfer procedures in this species which have precluded its adoption by the sheep breeding industry.

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