جستجوی مقالات مرتبط با کلیدواژه « frozen » در نشریات گروه « پزشکی »

Fresh stem cell exosomes are usually obtained and reused in the same individual. It cannot be kept viable for a long period of time regardless of the lengthy preparation time. Freezing is typically used to preserve the viability of perishable materials and increase their lifetime. Regrettably, normal freezing of biomaterials leads to cell damage. Therefore, a cryoprotectant can save the cells from the conventional cryodamage. Sodium carboxymethylcellulose (NA-CMC) is a powdery substance that is used to manufacture bio-safe hydrofilm gels because of its high viscosity, cytocompatibility, and nonallergenic nature.

Sterile CMC hydrogel was prepared, part of which was loaded with exosomal solution derived from MSCs. The gel was kept at −20°C for preservation. Two bilateral full-thickness circular skin wounds of 2-cm diameter were created on the back of experimental dogs. The wounds were at least 2.5 cm apart. Treatment started 24 hours after wound creation. Group I received CMC gel solely, whereas group II received frozen CMC exosomal gel. The gel was applied 4 times, a single application per day with 1- day interval.

Clinically, the frozen exosomal gel significantly promoted wound healing with no scaring. Histologically, enhanced dermal fibroblasts and organized collagen deposition were seen in the treated group.

CMC proved to be an efficient cryoprotectant and a suitable vehicle for exosomes. Deep freezing was proven to conserve the viability, extended the preservation, and facilitated the usage of exosomal gel. This technique of preserved cell-free therapy is inexpensive, time-saving, and proficient and seems suitable for treating cutaneous wounds.

Endometrial thickness is regarded as an indicator of the receptivity of the endometrium. Patients preparing for frozen embryo transfer need some interventions in case their endometrium is thin.

This study aimed to compare the clinical outcomes of oral administration of estradiol valerate with its vaginal type in women with inappropriate endometrial thickness.

This cross sectional study comprised of 79 women (cycles) who had undergone frozen-thawed embryo transfer. On the 13th day of the cycle, vaginal sonography was performed in case the thickness of the endometrium was < 7 mm; in the oral group, the patients continued using oral estradiol valerate tablet. However, in the vaginal group, the participants applied estradiol valerate tablet vaginally. Finally, the chemical and clinical pregnancy rate, also, early miscarriage rate were compared between the two groups.

The early miscarriage rate was lower in the vaginal group in comparison with the oral group (p = 0.040). Women in the vaginal group showed a lower rate of chemical pregnancy compared to the oral group, but this difference was not statistically significant (25.0 vs. 34.4%, p = 0.440). The rate of clinical pregnancy in the two groups was not statistically significant, although the vaginal group had a higher pregnancy rate (22.5% vs. 15.6%, p = 0.464), especially in women older than 34 years (37.5% vs. 11.1%, p = 0.355).

Vaginal administration of estradiol tablet in women with thin endometrium leads to a lower rate of early miscarriage.

The endometrial preparation with stimulating natural cycles for frozen embryo transfer (FET) have benefits like lower cost and ease of use.

Comparing the clinical outcome of letrozole versus hormone replacement (HR) for endometrial preparation in women with normal menstrual cycles for FET in artificial reproduction techniques.

A total of 167 participants who had frozen embryos and regular ovulatory cycles were randomly divided into two groups for endometrial preparation. One group (82 women) was stimulated with letrozole 5mg/day and the other group (85 women) was hormonally stimulated by oral estradiol valerate (2 mg three times a day). All participants were followed serially by ultrasonography. Any patient who did not reach optimal endometrial thickness was excluded from the study. Implantation, biochemical and clinical pregnancy and abortion rate were reported.

There was no significant difference in the mean age, duration, and primary or secondary infertility, cause of the infertility, number, and quality of transferred embryos between the groups. The mean estradiol level on the day of transfer was 643 ± 217 in the HR group and 547 ± 212 in the letrozole group (P = 0.01), which was significantly different. The clinical pregnancy rate was 38.7 in the letrozole group, higher than the HR group (25.3) but not significantly different (P=0.06).

For endometrial preparation in women with a normal cycle, letrozole yields higher pregnancy rate although it is not significant; due to its cost, ease in use, and lower side effects, letrozole is a good choice.

The efficacy of in vitro fertilization (IVF) for treating human infertility has only one final efficacy index and that is the achievement of a delivery. However, with the evolution of the freeze-all strategy, a new problem is arising for evaluating the performance of an embryological team. The aim of the study was to present a new representative index, combining fresh and frozen embryo transfer success rates. In this opinion article, apart from the effectiveness of managing fresh gametes and embryos, we wish to evaluate the efficacy of the processes of both freezing and thawing of the produced embryos. The reporting of pregnancy rates of an IVF unit in the past was primarily laying in the fresh embryo transfer (ET) pregnancy rates. Now with the most frequent utilization of freeze-all strategy, it does not seem logical to report only on poor prognosis patients as all the good cases are postponed for thawed cycles. Ongoing implementation of the freeze-all strategy has indicated the need to establish a new representative index that may combine the success of both fresh and frozen cycles performed in the same woman; an index that may not be biased by the policy of an IVF center towards or against the freeze-all strategy. This newly proposed index, which is referred to as COMFFETI (Combined Fresh & Frozen Embryo Transfers per Individual), describes the optimal way to report final reproductive outcomes in the present opinion article.

There are different methods in endometrial preparation for frozen-thawed embryo transfer (FET).

The purpose of this study was to compare the live birth rate in the artificial FET protocol (estradiol/ progesterone with GnRH-agonist) with stimulated cycle FET protocol (letrozole plus HMG).

This randomized clinical trial included 100 women (18-42 years) randomly assigned to two groups based on Bernoulli distribution. Group I received GnRH agonist [Bucerelin, 500μg subcutaneously] from the previous midlutea lcycle, Then estradiol valerat [2 mg/ daily orally] was started on the second day and was increased until the observation of 8mm endometrial thickness. Finally progesterone [Cyclogest, 800 mg, vaginally] was started. Group II received letrozole on the second day of the cycle for five days, then HMG 75 IU was injected on the7th day. After observing [18 mm folliclhCG10000 IU was injected for ovulation induction. Trans cervical embryo transfer was performed in two groups. The main outcome was the live birth rate. The rate of live birth, implantation, chemical, and clinical pregnancy, abortion, cancellation and endometrial thickness were compared between two groups.

Implantation rate was significantly higher in group I. Live birth rate was slightly increased in group I without significant difference (30% vs. 26%). The rate of chemical and clinical pregnancy was similar in two groups. The abortion rate was lower in letrozole protocol but the difference was not statistically significant. The mean endometrial thickness was not different between two groups.

Letrozole plus HMG method cannot improve pregnancy outcomes in frozen-thawed embryo transfer but it has only one injection compare to daily injections in artificial method.

Implantation failure is one of the most important factors limiting success in IVF treatment. The majority of trials have demonstrated favorable effect of endometrial injury on implantation success rate especially in women with recurrent implantation failure, while some studies failed to detect any benefit.

The purpose of our trial was to explore whether endometrial injury in luteal phase prior to frozen-thawed embryo transfer cycles would improve pregnancy outcomes?

We conducted a prospective controlled trial of 93 consecutive subjects at a research and clinical center for infertility. All women were undergone frozen-thawed embryo transfer (FTE) cycles. Women in the experimental group underwent endometrial biopsy with a Pipelle catheter in luteal phase proceeding FET cycle. Primary outcomes were implantation and clinical pregnancy rates and secondary outcomes were chemical, ongoing and multiple pregnancy and miscarriage rates.

45 subjects who underwent endometrial injury (EI) were compared with 48 control group which did not include any uterine manipulation. There were no significant differences in baseline and cycle characteristics between two groups. The difference in implantation rate was trend to statistically significance, 11.8% in EI group vs. 20.5% in control group (p=0.091). The chemical, clinical and ongoing pregnancy rates were lower in EI group compared with control group but not statistically significant. The multiple pregnancy rate and miscarriage rate also were lower in EI group compared with control group.

Based on results of this study, local injury to endometrium in luteal phase prior to FET cycle had a negative impact on implantation and clinical pregnancy rates.

Despite of higher pregnancy rate after frozen embryo transfer (FET) which is accepted by the majority of researches, the safety of this method and its effect on neonatal outcome is still under debate.

The aim of this study was to evaluate pregnancy and neonatal outcome of FET compare to fresh cycles.

In this study,1134 patients using fresh ET and 285 women underwent FET were investigated regarding live birth as primary outcome and gestational age, birth weight, gender, multiple status, ectopic pregnancy, still birth and pregnancy loss as secondary outcomes.

Our results showed that there is no difference between FET and fresh cycles regarding live birth (65.6% vs. 70.4% respectively). Ectopic pregnancy, still birth and abortion were similar in both groups. The mean gestational age was significantly lower among singletons in FET group compared to fresh cycles (p=0.047). Prematurity was significantly elevated among singleton infants in FET group (19.6%) in comparison to neonates born after fresh ET (12.8%) (p=0.037).

It seems that there is no major difference regarding perinatal outcome between fresh and frozen embryo transfer. Although, live birth is slightly increased in fresh cycles and prematurity was significantly increased among singleton infants in FET group.

There is no doubt that luteal phase support is essential to enhance the reproductive outcome in IVF cycles. In addition to progesterone and human chorionic gonadotropin, several studies have described GnRH agonists as luteal phase support to improve implantation rate, pregnancy rate and live birth rate, whereas other studies showed dissimilar conclusions. All of these studies have been done in fresh IVF cycles.

To determine whether an additional GnRH agonist administered at the time of implantation for luteal phase support in frozen-thawed embryo transfer (FET) improves the embryo developmental potential.

This is a prospective controlled trial study in 200 FET cycles, patients were randomized on the day of embryo transfer into group 1 (n=100) to whom a single dose of GnRH agonist (0.1 mg triptorelin) was administered three days after transfer and group 2 (n=100), who did not receive agonist. Both groups received daily vaginal progesterone suppositories plus estradiol valerate 6 mg daily. Primary outcome measure was clinical pregnancy rate. Secondary outcome measures were implantation rate, chemical, ongoing pregnancy rate and abortion rate.

A total of 200 FET cycles were analyzed. Demographic data and embryo quality were comparable between two groups. No statistically significant difference in clinical and ongoing pregnancy rates was observed between the two groups (26% versus 21%, p=0.40 and 21% versus 17%, p=0.37, respectively).

Administration of a subcutaneous GnRH agonist at the time of implantation does not increase clinical or ongoing pregnancy.

To investigate the reproductive outcome of artificial endometrial preparation with exogenous steroids for frozen-thawed embryo transfer with and without pre-treatment with depot gonadotropin releasing hormone agonist (GnRH-a) in women with regular menses.This is a prospective randomized clinical trial conducted in two ART centers on 176 women undergoing frozen-thawed embryo transfer. All patients received oral estradiol valerate 4 mg daily from day 2 to day 5 and 6 mg per day from day 6 to the day of the pregnancy test. In day 13 of cycle, an ultrasound examination was performed. After ultrasound confirmation of endometrial thickness (≥8 mm) and no ovarian activity, progesterone in cyclogest supp (800 mg daily) was added. The dose of estradiol would be increased to 8 mg per day if the endometrial thickness was less than 8mm. Two or 3 embryos were transferred via transcervical route 48 hours after the beginning of progesterone administration. In group A (93 patients), Difereline (3.75 mg Im), as a depot GnRH agonist was administered in the midluteal phase (day 21) of previous cycle. In the other group B (n = 83) steroid supplementation was commenced without prior pituitary suppression. Chemical and clinical pregnancy rates were compared in two groups.No significant differences were seen between two groups in terms of chemical pregnancy and clinical pregnancy rates.The findings support the artificial protocol without any pretreatment suppressive drugs to reduce the adverse side effects of GnRH agonists also to minimize the costs.