Best site for embryo transfer: the upper or lower half of endometrial cavity?

BACKGROUND: the objective of the present study was to determine the importance of the site of embryo transfer (upper or lower half endometrial cavity) on implantation and clinical pregnancy rates. METHODS: A total of 400 transfers guided by ultrasound were randomly assigned to two groups according to the distance between the uterine fundus and the catheter tip at the time of embryo placement. Group I (n=200) consisted of transfers corresponding to a distance of <50% of the endometrial cavity length (ECL), i.e. transfer in upper half of the cavity; and group II (n=200) consisted of transfers corresponding to a distance of greater than or equal to50%, of the ECL, i.e. transfer in lower half of cavity. The Student's t-test, Mann-Whitney test and Fisher's exact test were used where appropriate. RESULTS: the general characteristics of the study population and the main transfer cycle characteristics had an equal distribution (P>0.05) between groups I and II. No significant difference in implantation or pregnancy rates was observed between groups I and II. CONCLUSION: the implantation or pregnancy rates were similar whether the embryos were deposited in the upper or lower half of the endometrial cavity.

Single-embryo transfer reduces clinical pregnancy rates and live births in fresh IVF and Intracytoplasmic Sperm Injection (ICSI) cycles: a meta-analysis

Background: It has become an accepted procedure to transfer more than one embryo to the patient to achieve acceptable ongoing pregnancy rates. However, transfers of more than a single embryo increase the probability of establishing a multiple gestation. Single-embryo transfer can minimize twin pregnancies but may also lower live birth rates. This meta-analysis aimed to compare current data on single-embryo versus double-embryo transfer in fresh IVF/ICSI cycles with respect to implantation, ongoing pregnancy and live birth rates.Methods: Search strategies included on-line surveys of databases from 1995 to 2008. Data management and analysis were conducted using the Stats Direct statistical software. The fixed-effect model was used for odds ratio (OR). Fixed-effect effectiveness was evaluated by the Mantel Haenszel method. Seven trials fulfilled the inclusion criteria.Results: When pooling results under the fixed-effect model, the implantation rate was not significantly different between double-embryo transfer (34.5%) and single-embryo transfer group (34.7%) (P = 0.96; OR = 0.99, 95% CI 0.78, 1.25). on the other hand, double-embryo transfer produced a statistically significantly higher ongoing clinical pregnancy rate (44.5%) than single-embryo transfer (28.3%) (P < 0.0001; OR: 2.06, 95% CI = 1.64,2.60). At the same time, pooling results presented a significantly higher live birth rate when double-embryo transfer (42.5%) (P < 0.001; OR: 1.87, 95% CI = 1.44,2.42) was compared with single-embryo transfer (28.4%).Conclusion: Meta-analysis with 95% confidence showed that, despite similar implantation rates, fresh double-embryo transfer had a 1.64 to 2.60 times greater ongoing pregnancy rate and 1.44 to 2.42 times greater live birth rate than single-embryo transfer in a population suitable for ART treatment.

Transfer of Maternal Immunity to Newborns of Diabetic Mothers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Detection and transfer of antimicrobial resistance gene integron in Salmonella Enteritidis derived from avian material

The expansion of global poultry production has increased the need to reduce or control the agents responsible for economic losses, including Salmonella spp. These bacteria are also of public health concern due to their potential to cause food poisoning, and, more recently, due to the antimicrobial resistance presented by these bacteria. Molecular biology is an important tool currently used in the diagnosis and research studies of main poultry diseases. The present studied analyzed 100 samples of Salmonella Enteritidis (SE) isolated from avian material aiming at detecting the class 1 integron gene, Integroninvolved in antimicrobial resistance, by means of polymerase chain reaction (PCR), and comparing it with plate inhibition test. Subsequently, SE samples were evaluated for their capacity to horizontally transfer this gene. There was no direct relationship between the presence of the class 1 integron gene and SE resistance to the 14 antimicrobials tested, as 80% of the studied samples were resistant to up to three antimicrobials, and did not present the aforementioned gene. However, horizontal transfer of this gene was accomplished in vitro (from Escherichia coli to Salmonella Enteritidis), demonstrating that capacity class 1 integron gene can be disseminated among enterobacteria.

Factors affecting conception rates following artificial insemination or embryo transfer in lactating holstein cows

The objective of this study was to evaluate the factors that may affect conception rates (CR) following artificial insemination (AI) or embryo transfer (ET) in lactating Holstein cows. Estrous cycling cows producing 33.1 +/- 7.2 kg of milk/d received PGF(2 alpha) injections and were assigned randomly to 1 of 2 groups (AI or ET). Cows detected in estrus (n = 387) between 48 and 96 h after the PGF2a injection received AI (n = 227) 12 h after detection of estrus or ET (n = 160) 6 to 8 d later (1 fresh embryo, grade 1 or 2, produced from nonlactating cows). Pregnancy was diagnosed at 28 and 42 d after estrus, and embryonic loss occurred when a cow was pregnant on d 28 but not pregnant on d 42. Ovulation, conception, and embryonic loss were analyzed by a logistic model to evaluate the effects of covariates [days in milk (DIM), milk yield, body temperature (BT) at d 7 and 14 post-AI, and serum concentration of progesterone (P4) at d 7 and 14 post-AI] on the probability of success. The first analysis included all cows that were detected in estrus. The CR of AI and ET were different on d 28 (AI, 32.6% vs. ET, 49.4%) and 42 (AI, 29.1% vs. ET, 38.8%) and were negatively influenced by high BT (d 7) and DIM. The second analysis included only cows with a corpus luteum on d 7. Ovulation rate was 84.8% and was only negatively affected by DIM. Conception rates of AI and ET were different on d 28 (AI, 37.9% vs. ET, 59.4%) and 42 (AI, 33.8% vs. ET, 46.6%) and were negatively influenced by high BT (d 7). The third analysis included only ovulating cows that were 7 d postestrus. Conception rates of AI and ET were different on d 28 (AI, 37.5% vs. ET, 63.2%) and 42 (AI, 31.7% vs. ET, 51.7%) and were negatively influenced by high BT (d 7). There was a positive effect of serum concentration of P4 and a negative effect of milk production on the probability of conception for the AI group but not for the ET group. The fourth analysis was embryonic loss (AI, 10.8% vs. ET, 21.5%). The transfer of fresh embryos is an important tool to increase the probability of conception of lactating Holstein cows because it can bypass the negative effects of milk production and low P4 on the early embryo. The superiority of ET vs. AI is more evident in high-producing cows. High BT measured on d 7 had a negative effect on CR and embryonic retention.

Comparison of progesterone-based protocols with gonadotropin-releasing hormone or estradiol benzoate for timed artificial insemination or embryo transfer in lactating dairy cows

The objective was to compare two protocols for synchronizing ovulation in lactating Holstein cows submitted to timed AI (TAI) or timed ET (TET). Within each farm (n = 8), cows (n = 883; mean +/- SEM 166.24 +/- 3.27 d postpartum, yielding 36.8 +/- 0.34 kg of milk/d) were randomly assigned to receive either: 1) an intravaginal progesterone insert (CIDR (R)) with 1.9 g of progesterone + GnRH on Day -10, CIDR (R) withdrawal + PGF2 alpha on Day -3, and 1 mg estradiol cypionate on Day -2 (treatment GP-P-E; n(TAI) = 180; n(TET) = 260); or 2) a CIDR (R) insert + 2 mg estradiol benzoate on Day -10, PGF2 alpha on Day -3, CIDR (R) withdrawal + 1 mg estradiol cypionate on Day -2 (treatment EP-P-E; n(TAI) = 174; n(TET) = 269). Cows were subsequently randomly assigned to receive either TAT on Day 0 or TET on Day 7. Serum progesterone concentration on Day -3 was greater in GP-P-E than in EP-P-E (2.89 +/- 0.15 vs 2.29 +/- 0.15 ng/mL; P < 0.01), with no significant effect of group on serum progesterone on Day 7. Compared to cows submitted to TAI, those submitted to TET had greater pregnancy rates on Day 28 (44.0% [233/5291 vs 29.7% [105/354]; p < 0.001) and on Day 60 (37.6% [199/529] vs 26.5 [94/354]; P < 0.001). However, there were no effects of treatments (GP-P-E vs EP-P-E; P > 0.10) on synchronization (87.0% [383/440] vs 85.3% [378/443]), conception (TAI: 35.3% [55/156] vs 33.8% [50/148]; TET: 50.7% [115/227] vs 51.3% [118/230]) and pregnancy rates on Days 28 (TAT: 30.5% [55/180] vs 28.7% 150/174]; TET: 44.2% [115/260] vs 43.9% [118/2691) and 60 (TAI: 27.2% [49/80] vs 25.9% [45/174]; TET: 38.8% [101/260] vs 36.4% [98/269]). In conclusion, GP-P-E increased serum progesterone concentrations on Day -3, but rates of synchronization, conception, and pregnancy were not significantly different between cows submitted to GP-P-E and EP-P-E protocols, regardless of whether they were inseminated or received an embryo. (c) 2011 Elsevier B.V. All rights reserved.

Effects of postbreeding gonadotropin treatments on conception rates of lactating dairy cows subjected to timed artificial insemination or embryo transfer in a tropical environment

The objective of experiment 1 was to evaluate the effects of treatments with human chorionic gonadotropin (hCG) or GnRH 7 d after induced ovulation on reproductive performance of lactating dairy cows submitted to timed artificial insemination (TAI) or timed embryo transfer (TET). A total of 834 potential breedings were used from 661 lactating Holstein cows (37.3 +/- 0.3 kg of milk/d). Cows had ovulation synchronized and were assigned randomly to receive TAI on d 0 or TET on d 7. Within each group, cows were assigned randomly to receive on d 7 no additional treatment (control; n(TAI) = 156; n(TET) = 126), a 100 mu g i.m. injection of GnRH (n(TAI) = 155; n(TET) = 124), or a 2,500 TU i.m. injection of hCG (ITA = 151; n(TET) = 122). Postbreeding treatment affected the percentages of pregnant cows at TET on d 28 (control: 38.1%; GnRH: 52.4%; hCG: 45.1%) and on d 60 (control: 32.5%; GnRH: 41.1%; hCG: 38.5%), but postbreeding treatment did not affect percentages of pregnant cows at TAT on d 28 (control: 30.1%; GnRH: 32.2%; hCG: 32.4%) or on d 60 (control: 25.6%; GnRH: 27.1%; hCG: 29.8%). The objective of experiment 2 was to evaluate the effect of a treatment with GnRH 7 d after TET on reproductive performance of lactating dairy cows that received a previous GnRH treatment at TET. A total of 285 potential breedings were used from 257 lactating Holstein cows (35.1 +/- 0.8 kg of milk/d). Cows had ovulation synchronized and were assigned for TET on d 7. Immediately after TET, all cows were treated with a 100 mu g i.m. injection of GnRH. on d 14, cows were assigned randomly to receive (G7-14; n = 147) or not (G7; n = 138) an additional injection of GnRH. Pregnancy diagnosis were performed on d 28 and 60. The additional treatment with GnRH on d 14 did not affect the percentages of pregnant cows on d 28 (G7: 48.5%; G7-14: 42.9%) or on d 60 (G7: 39.8%; G7-14: 37.4%). In conclusion, treatment with GnRH or hCG 7 d after induced ovulation increased conception rates in lactating dairy cows submitted to TET, but not in cows submitted to TAI. Moreover, treatment with GnRH 7 d after TET did not enhance reproductive performance of lactating dairy cows that received a previous GnRH treatment at TET.

Use of oocyte transfer in a commercial breeding program for mares with reproductive abnormalities

In some mares with lesions of the reproductive tract, embryo collection and survival rates are low or collection of embryos is not feasible. For these mares, oocyte transfer has been proposed as a method to induce pregnancies. In this report, a method for oocyte transfer in mares and results of oocyte transfer performed over 2 breeding seasons, using mares with long histories of subfertility and various reproductive lesions, are described.Human chorionic gonadotropin or an implant containing a gonadotropin-releasing hormone analog was used to initiate follicular and oocyte maturation. Oocytes were collected by means of transvaginal ultrasound-guided follicular aspiration. Following follicular aspiration, cumulus oocyte complexes were evaluated for cumulus expansion and signs of atresia; immature oocytes were cultured in vitro to allow maturation. The recipient's ovary and uterine tube (oviduct) were exposed through a flank laparotomy with the horse standing, and the oocyte was slowly deposited within the oviduct. Oocyte transfer was attempted in 38 mares between 9 and 30 years old during 2 successive breeding seasons. All mares had a history of reproductive failure while in breeding and embryo transfer programs. Twenty pregnancies were induced. Fourteen of the pregnant mares delivered live foals. Results suggest that oocyte transfer can be a successful method for inducing pregnancy in subfertile mares in a commercial setting..

The use of transmission electron microscopy and oocyte transfer to evaluate in vitro maturation of equine oocytes in different culture conditions

The current study evaluates the ability of equine oocytes matured in different conditions to undergo nuclear and cytoplasmic maturation.. After oocyte transfer, embryonic development was diagnosed at 1.5 and 90 days of gestation. For each group, immature oocytes obtained from slaughterhouse ovaries were matured in vitro (5 replicates). In experiment I, three different media were tested. HTF:BME, SOFaa, and TCM 199. In experiment 11, the HTF:BME was chosen as maturation medium containing pFSH, eFSH, or eFSH + eGH. Nuclear maturation was estimated after stripping the oocytes and staining with Hoechst 33342. The evaluation of cytoplasmic maturation was performed by transmission electron microscopy. For oocyte transfer, six non-cycling recipient mares were used, and 8 to 15 oocytes were transferred in each mare. In experiment I, the results showed no differences (P > .05) in nuclear maturation (MII) among experimental groups. The percentage of MII was 29.3 ( +/- 9.6), 23.4 ( +/- 8.4), and 13.5 ( +/- 12.4) for HTF:BME, SOF, and TCM, respectively. In experiment II, all media tested were efficient in inducing metaphase II. Also, no statistical differences (P > .05) were observed in percentages of nuclear maturation rates when porcine (37.1 +/- 22.4) or equine (25.8 +/- 8.2) FSH were used, or when eFSH + eGH was added to HTF:BME (29.4 +/- 12.3). The analysis of cytoplasmic morphology of oocytes cultured in TCM 199 and SOFaa showed signs of incomplete cytoplasmic maturation and premature cortical reaction. Meanwhile, oocytes cultured in HTF:BME medium presented cytoplasmic characteristics similar to those described by others for in vivo-matured oocytes. The addition of eFSH to the HTF:BME medium resulted in an improvement of cytoplasmic morphology. After oocyte transfer, two mares became pregnant, one from pFSH group and one from eFSH+eGH group. These results indicate that although in vitro matured equine oocytes are capable of fertilization and embryonic development, the percentage of competent oocytes is still low.

Viability of OPS Vitrified Sheep Embryos After Direct Transfer

The aim of this study was to evaluate the viability in the effect of open pulled straw (OPS) vitrification procedure of sheep embryos after direct transference. Embryos were produced in vivo and cryopreserved in slow freezing or OPS vitrification. The survival rates of cryopreserved embryos were compared to non-frozen standard pattern. In a first set of experiments, embryos at morula and blastocyst stages were dived in ethylene glycol (1.5 M) and frozen in an automatic freezer. After being thawed, they were directly or indirectly transferred to ewes recipient. A second group of embryos were drawn into OPS and plunged into liquid nitrogen after being exposed at room temperature for 1 min and 45 s in 10% EG plus 10% dimethyl sulphoxide (DMSO), then again for 30 s in 20% EG + 20% DMSO + 0.5 M sucrose. After being warmed, embryos were also directly transferred using a French mini straw as the catheter for the transplantation process or after in vitro dilution of cryoprotectants (two-step-process). No significant difference was observed among fresh, frozen or vitrified embryos on pregnancy rate (50.0%, 38.6% and 55.8%). However, when we evaluated only the direct transference, the pregnancy rate of OPS vitrified embryos was higher than that of frozen embryos (57.1% vs 34.8%) (p = 0.07). In addition, vitrified morulae had a higher pregnancy rate than the one with frozen embryos (64.0% vs 38.9%) (p = 0.07). Finally, our results indicate that OPS vitrification technique in association with direct transference improves the viability of sheep embryos with potential applications to field conditions.