Methods of artificial fertilization: gamete insemination fallopian tube (GIFT), zygosity insemination fallopian tubes (ZIFT).

GIFT (gamete intrafallopian transfer) and ZIFT (zygote intrafallopian transfer) are modified versions of in vitro fertilization. Like IVF, these procedures involve retrieving an egg from the woman and re-implanting it after manipulation. Unlike IVF, the timing between mixing the sperm and eggs and the transfer is faster.

In GIFT, the sperm and eggs are mixed together and immediately inserted. On the other hand, with ZIFT, the fertilized eggs --”zygotes”-- are inserted within 24 hours of the mixing.

What are the advantages to these procedures?

While the success rates are similar to IVF, the processes used in GIFT and ZIFT are closer to natural conception. In ZIFT, the eggs are placed in the fallopian tubes rather than directly in the uterus. With GIFT, fertilization actually takes place in the body rather than in a petri dish.

As in vitro fertilization techniques have become more refined, GIFT and ZIFT have become less relied upon. Additionally, as GIFT and ZIFT require surgery while IVF does not, IVF is the preferred choice in clinics. In vitro fertilization accounts for at least 98% of all assisted reproductive technology procedures performed in the U.S., while GIFT and ZIFT make up less than 2%.

What Types of Infertility Are Addressed By Gift and Zift?

GIFT and ZIFT can be used to treat many types of infertility, except cases caused by damage or abnormalities of the fallopian tubes. These techniques can also be used in cases of mild male infertility, as long as the sperm is capable of fertilizing an egg.

GIFT: What You Can Expect

Eggs and sperm are collected just as they would be in an IVF procedure, but after that, the two techniques differ. Unlike IVF, GIFT requires an incision be made in the abdomen and the eggs and sperm placed in the fallopian tubes using a laparoscope.

Because the eggs and sperm are placed into the fallopian tubes before conception, there's no way to know if fertilization has taken place prior to transfer. Typically, more eggs will be used in GIFT to ensure pregnancy, which has the side effect of increased multiple births.

ZIFT: What You can Expect

Unlike GIFT, with ZIFT the sperm and egg are mixed together in the laboratory, and given time to fertilize before being transferred to the fallopian tubes thus lowering the number of eggs used and correspondingly the chances for multiple pregnancy. As this is a post-fertilization technique, ZIFT is closer to in vitro fertilization. ZIFT, like GIFT, requires the procedure be performed by laparoscopy.

)Methods for determining the viability of eggs, sperm and embryos

The method for determining the viability of embryos relates to agriculture and can be used for embryo transfer in farm animals. The invention consists in that the embryo quality assessed twice: before freezing, then after freezing and thawing and by comparing the results of these evaluations is determined embryo viability. To carry viable embryos that have not changed their evaluation process of cryopreservation. The method improves the accuracy of determining the viability of embryos during freezing and in the degree of change in the quality of their results to predict engraftment after non-surgical transplantation. The method also allows the use of embryos rating 3 points to freeze.
There are methods for assessing the quality of embryos in vitro, which involve the use of dyes that detect enzyme activity (fluorescein diacetate) (2) or a special label that defines membrane damage in a defective condition of embryonic cells (3). However, these methods are not without drawbacks, as the additional manipulation of embryos during their assessments can cause the reduction or complete loss of their ability to further development, in addition, they require additional costs for reagents and efforts of experts.
Closer to the present invention is a method of temporary embryo culture in vitro in the laboratory to refine the quality assessment based on morphological criteria (1). Work to assess the embryo is performed under a stereo microscope with a magnification of 60-80 times, given the stage of embryo development, compliance with its chronological age, determine the morphology of embryos and, on the basis of these criteria, assess the quality of the embryo and its suitability for further use.
There were and there are many misconceptions about the speed of movement and life span of sperm. Now we know that the time during which the spermatozoa retain their mobility, as well as the period of their ability oplototvoryayuschey much shorter than previously thought. Preservation of sperm motility was seen as an indicator of fertility. Now we know that mobility continues for much longer than the ability to fertilize. The rabbit, for example, found experimentally that the sperm lose the ability to fertilize after about tridtsatichasovogo stay in the female genital tract, while their mobility continues up to two days. Unfortunately, similar data on human sperm is not as accurate. It is believed that their fertilizing capacity is maintained for 1-2 days, and mobility, apparently, 2 times longer.
The method developed by scientists an opportunity to assess the viability of the embryo, is based on the observation of the movements taking place in the egg immediately after fertilization. At this point, the nature and rate of pulsation of the cytoplasm, scientists can determine the possible viability of the fetus.
These conclusions are based on the observations of experts for bulges and protrusions on the surface of a fertilized egg, which appear and disappear in the process of ripple cytoplasm.
These characteristic movements going on about four hours associated with activation of actin and myosin cytoskeleton. Fluctuations in the concentration of calcium ions that accompany the process of fertilization, cause changes in the structure of the cytoskeleton. The speed and nature of such movements suggest how to viable embryo.
The results of these studies have great value, especially for in vitro fertilization (IVF), in which fusion of gametes carried out "in vitro", after which the fertilized egg is implanted future mother. This process, in vitro fertilization, is not always succeeds, doctors sometimes have to implant several fertilized eggs, and the status of the embryo assessed by analyzing the cells of the embryo.

 

79 icrosurgery techniques for embryonic cells (morula, blastocyst), leading to creation of allophenic animals One promising area in the early embryo micromanipulation is the artificial production of chimeras, or genetiТ osaics.
The concept of a chimera (grech.Chimaira) is a composite animal. The essence of a biotechnological method of obtaining the chimeras is an artificial combination with microsurgical manipulation of embryonic cells of two (or more) of animals of different breeds and even species. Thus, animals - chimeras are one body features two embryos differing different genotypes (Fig. 9.10).
It is believed that a successful embryo transfer can be carried out only between females of one species. Transfer of embryos, for example, sheep and goats to the contrary, accompanied by their engraftment but terminates the birth of offspring. In all cases, the immediate cause of interspecific pregnancy abortion is a violation of the function of the placenta due to maternal immunological response to foreign antigens of the fetus. This incompatibility can be overcome produce chimeric embryos by microsurgery using the following methods:
The first method is to obtain chimeras based on combining blastomeres from embryos of the same species. For this purpose, the chimeric embryos obtained complex sheep combining 2 -, 4 -, 8-cell embryos. Each embryo is a complex joint comprised of an equal number of blastomeres of embryos 2-8 parents. Transplant the inner cell mass of each donor (blastomeres) by injection into blastocysts transferred recipients.
The total number of cells varied from four to eight times larger than number of normal cells. The embryos were injected into the oviducts of sheep ligature tied to development to the blastocyst stage. Normally developing blastocysts were transplanted to recipients and get live lambs, most of which were chimeric, according to the analysis of blood and external features.
A second method to obtain chimeras based on cell mass fusion of two or more embryos in a zona pellucida. This method can obtain aggregation chimeras. The method consists in the fact that the 8-cell embryos were incubated in a medium with a proteolytic enzyme digesting shell egg. Freed from the shells of embryos in contact with each other, resulting in their cells fuse and mixed. Artificial obtaining chimeras began in the mid 70's. In animal known as man-made chimera intraspecific and interspecific.
In Germany, the obtained aggregation chimeric animals after joining the halves of 5-6 day old embryos from donor cows and Schwyz Holstein cattle. Of the seven calves produced in five there was no evidence of chimerism, and the two combined in a phenotype characteristic suit two source rocks - brown and black-and-white.
The features observed in the preparation of inter-specific hybrids. Interspecific chimeras - embryos after embryo transfer prizhivlyayutsya only 10% of cases. An example of obtaining interspecific chimeras in livestock are ovtsekozy, combining features of the sheep and goats.
The authors note that the chimeric animals do not transmit to posterity their characteristic genetic mosaicism. Like heterozygous or hybrid animals in the offspring is split, resulting in a broken valuable genetic combinations.