ICSI

April 15, 2012 By

Intracytoplasmic sperm injection (ICSI, pronounced “eeksee”[1] or “icksy”[2]) is an in vitro fertilization procedure in which a single sperm is injected directly into an egg.

Indications

This procedure is most commonly used to overcome male infertility problems, although it may also be used where eggs cannot easily be penetrated by sperm, and occasionally in addition to sperm donation.

It can be used in teratozoospermia, because once the egg is fertilized, abnormal sperm morphology does not appear to influence blastocyst development or blastocyst morphology.Even with severe teratozoospermia, microscopy can still detect the few sperm cells that have a “normal” morphology, allowing for optimal success rate. If you are the student going to pursue education overseas click here to know about the health insurance policies. The first American baby was conceived with the technique At Reproductive Biology Associates (RBA) in Atlanta, Georgia in 1992 under the direction of Michael Tucker, PhD and Joe Massey, MD. ( ref. Case report, American Society for Reproductive Medicine, Abstract report at ASRM meeting, Montreal, Canada, 1993.) The first large experience with the technique in the United States was published by Joseph D. Schulman and colleagues at Genetics and IVF Institute in 1995.

Procedure

ICSI is generally performed in addition an in vitro fertilisation procedure to extract often several oocytes from a woman.
The procedure is done under a microscope using multiple micromanipulation devices (micromanipulator, microinjectors and micropipettes). A holding pipette stabilizes the mature oocyte with gentle suction applied by a microinjector. From the opposite side a thin, hollow glass micropipette is used to collect a single sperm, having immobilised it by cutting its tail with the point of the micropipette. The oocyte is pierced through the oolemma and into the inner part of the oocyte (cytoplasm). The sperm is then released into the oocyte. The pictured oocyte has an extruded polar body at about 12 o’clock indicating its maturity. After the procedure, the oocyte will be placed into cell culture and checked on the following day for signs of fertilization.

In contrast, in natural fertilization sperm compete and when the first sperm penetrates the oolemma, the oolemma hardens to block the entry of any other sperm. Concern has been raised that in ICSI this sperm selection process is bypassed and the sperm is selected by the embryologist without any specific testing. However, in mid 2006 the FDA cleared a device that allows embryologists to select mature sperm for ICSI based on sperm binding to hyaluronan, the main constituent of the gel layer (cumulus oophorus) surrounding the oocyte. The device provides microscopic droplets of hyaluronan hydrogel attached to the culture dish. Parents in the old age are bound to fall sick frequently hence if they are visiting their children overseas they need to have a health insurance for parents from India to overcome the expensive medical bills. The embryologist places the prepared sperm on the microdot, selects and captures sperm that bind to the dot. Basic research on the maturation of sperm shows that hyaluronan-binding sperm are more mature and show fewer DNA strand breaks and significantly lower levels of aneuploidy than the sperm population from which they were selected. A brand name for one such sperm selection device is PICSI.

‘Washed’ or ‘unwashed’ sperm may be used in the process.

Addition of a GNRH agonist for luteal support in ICSI cycles has been estimated to increase success rates, by a live birth rate RD of +16% (95% confidence interval +10 to +22%)

Courtesy: wikipedia.org

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IVF

April 15, 2012 By

In vitro fertilisation (IVF) is a process by which an egg is fertilised by sperm outside the body: in vitro. IVF is a major treatment for infertility when other methods of assisted reproductive technology have failed. The process involves monitoring a woman’s ovulatory process, removing ovum or ova (egg or eggs) from the woman’s ovaries and letting sperm fertilise them in a fluid medium in a laboratory. When a woman’s natural cycle is monitored to collect a naturally selected ovum (egg) for fertilisation, it is known as natural cycle IVF. The fertilised egg (zygote) is then transferred to the patient’s uterus with the intent to establish a successful pregnancy. The first successful birth of a “test tube baby”, Louise Brown, occurred in 1978. Louise Brown was born as a result of natural cycle IVF. Robert G. Edwards, the physiologist who developed the treatment, was awarded the Nobel Prize in Physiology or Medicine in 2010.

The term in vitro, from the Latin meaning in glass, is used, because early biological experiments involving cultivation of tissues outside the living organism from which they came, were carried out in glass containers such as beakers, test tubes, or petri dishes. Today, the term in vitro is used to refer to any biological procedure that is performed outside the organism it would normally be occurring in, to distinguish it from an in vivo procedure, where the tissue remains inside the living organism within which it is normally found. A colloquial term for babies conceived as the result of IVF, “test tube babies”, refers to the tube-shaped containers of glass or plastic resin, called test tubes, that are commonly used in chemistry labs and biology labs. However, in vitro fertilisation is usually performed in the shallower containers called Petri dishes. One IVF method, Autologous Endometrial Coculture, is actually performed on organic material, but is still considered in vitro.

Courtesy: wikipedia.org

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Ovulation induction

April 15, 2012 By

Ovulation induction is the stimulation of ovulation by medication. It is usually used in the sense of stimulation of the development of ovarian follicles to reverse anovulation or oligoovulation, Students going overseas to pursue education, universities have made the international student health insurance mandatory. but can also be used in the sense of triggering oocyte release from relatively mature ovarian follicles. In any case, ovarian stimulation (in the sense of stimulating the development of oocytes) is often used in conjunction with (“strict”) ovulation induction. Also, a few definitions also include ovarian hyperstimulation (stimulating the development of multiple follicles of the ovaries in one single cycle) in the definition of ovarian stimulation. Otherwise, ovarian hyperstimulation may still be a side effect of ovulation induction.

Reversing anovulation or oligoovulation

Ovulation induction in the sense of reversing anovulation or oligoovulation is indicated for women who do not ovulate on their own regularly, such as those with Polycystic ovary syndrome (PCOS). The medication which is most commonly used to treat anovulation is clomifene citrate (or clomid), which is a selective estrogen receptor modulator (SERM) that increases production of gonadotropins by inhibiting negative feedback from estrogen on the hypothalamus.
Also, where anovulation or oligovulation is secondary to another disease, the treatment for the underlying disease can be regarded as ovulation induction, by indirectly resulting in ovulation.

Triggering oocyte release

Ovulation induction in the sense of triggering the release of oocytes from already relatively developed follicles can be more more specifically termed oocyte release triggering. Colloquially, this is known as the “trigger shot.” However, the process generally includes acceleration of the final maturation of oocytes as well, and thereby partly overlaps with the processes of ovarian hyperstimulation and reversal of anovulation or oligovulation. The triggering of oocyte release is equivalent to the physiological role the LH surge by luteinizing hormone.

Administration of medication for triggering of oocyte release avails for sexual intercourse or intrauterine insemination to be scheduled at ovulation, the most likely time to achieve pregnancy. In in vitro fertilization, it avails for final maturation of the oocytes and proper timing of egg retrieval.

Medications that can trigger oocyte release include:

A low dose of human chorionic gonadotropin (HCG or hCG), which may be injected after completed ovarian stimulation. Ovulation will occur between 38 and 40 hours after a single HCG injection. It is also used in in vitro fertilization, where it makes the follicles perform their final maturation. A transvaginal oocyte retrieval is then performed at a time usually between 34 and 36 hours after hCG injection, that is, just prior to when the follicles would rupture. This avails for scheduling the egg retrieval procedure at a time where the eggs are fully mature. HCG injection confers a risk of ovarian hyperstimulation syndrome.

Oocyte release triggering with a GnRH agonist is a valid alternative to HCG triggering, resulting in an elimination of the risk of ovarian hyperstimulation syndrome. The delivery rate is approximately 6% less than with hCG triggering.

Courtesy: wikipedia.org

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PGD or PIGD

April 15, 2012 By

In medicine and (clinical) genetics pre-implantation genetic diagnosis (PGD or PIGD) (also known as embryo screening) refers to procedures that are performed on embryos prior to implantation, sometimes even on oocytes prior to fertilization. Travelling to US for vacation or business always do carry a travel insurance for USA. PGD is considered another way to prenatal diagnosis. When used to screen for a specific genetic disease, its main advantage is that it avoids selective pregnancy termination as the method makes it highly likely that the baby will be free of the disease under consideration. PGD thus is an adjunct to assisted reproductive technology, and requires in vitro fertilization (IVF) to obtain oocytes or embryos for evaluation.

The term pre-implantation genetic screening (PGS) is used to denote procedures that do not look for a specific disease but use PGD techniques to identify embryos at risk. PGD is a poorly chosen phrase because, in medicine, to “diagnose” means to identify an illness or determine its cause. An oocyte or early-stage embryo has no symptoms of disease. They are not ill. Rather, they may have a genetic condition that could lead to disease. To “screen” means to test for anatomical, physiological, or genetic conditions in the absence of symptoms of disease. So both PGD and PGS should be referred to as types of embryo screening.

The procedures may also be called preimplantation genetic profiling to adapt to the fact that they are sometimes used on oocytes or embryos prior to implantation for other reasons than diagnosis or screening.

Procedures performed on sex cells before fertilization may instead be referred to as methods of oocyte selection or sperm selection, although the methods and aims partly overlap with PGD.

Courtesy: wikipedia.org

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