Hamster zona-free ovum test

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The hamster zona-free ovum test (HZFO test), or hamster egg-penetration test, or sometimes just hamster test, is an in-vitro test used to study physiological profile of spermatozoa. [1] The primary application of the test is to diagnose male infertility caused by sperm unable to penetrate the ova. The test has limited value, due to expense and a high false negative rate. [2]

Contents

Hamster zona-free ovum test
Purposeto diagnose male infertility

Procedure

In this test, sperm are incubated with several hamster eggs. After seven to twenty hours, the number of sperm penetrations per egg is measured. The hamster eggs have had the zona pellucida, the outer membrane, removed—hence, zona-free. [3]

Having all eggs penetrated by multiple sperm is considered to be a positive sign for fertility. Results suggest that men whose sperm fail the hamster test are a third as fertile than those whose sperm pass. [4]

Although medical professionals often present the procedure as unable to create an embryo, [5] these claims are not technically correct. If the human sperm succeeds in penetrating the hamster egg, a hybrid embryo is indeed created, known as a humster. [6] These embryos are typically destroyed before they divide into two cells; were they left alone to divide, they would still be unviable. [7]

The practice is made licensable in the United Kingdom by the Human Fertilisation and Embryology Act 1990. [8]

Use

The hamster zona-free ovum test was frequently performed by sperm banks when screening potential sperm donors. It was particularly useful in assessing the extent to which sperm from a potential donor could penetrate cervical mucus when artificial insemination was principally performed by ICI or IVI, rather than by IUI. It may still be used when the sperm of a donor is intended to be used in IVF procedures because it can illustrate the ease by which the sperm can penetrate the egg. However, owing to the unreliability of these tests and the advancement of computer tests for the screening of sperm, tests by sperm banks using these methods largely fell out of favour during the 1990s.

Significance

Donated sperm and intracytoplasmic sperm injection techniques are considered more strongly for those whose sperm fail this test.

This test evaluates the acrosome reaction of human spermatozoa. However, the incidence of acrosome reaction in freely swimming human sperm does not accurately reflect the fertilizing ability of the sperm. [9] [10]

This test has a poor predictive value for the success of fertilization in IVF treatment at any insemination concentration. [10] No strong correlation has been found between hamster egg penetration rates and the various semen parameters and the role of the hamster egg penetration test in the investigation of the causes of infertility should be evaluated further. [11] However, a negative result on the hamster test correlates with a lower probability of the man's partner becoming pregnant. [12]

See also

Related Research Articles

<span class="mw-page-title-main">Spermatozoon</span> Motile sperm cell

A spermatozoon is a motile sperm cell, or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote.

<span class="mw-page-title-main">Fertilisation</span> Union of gametes of opposite sexes during the process of sexual reproduction to form a zygote

Fertilisation or fertilization, also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. While processes such as insemination or pollination which happen before the fusion of gametes are also sometimes informally referred to as fertilisation, these are technically separate processes. The cycle of fertilisation and development of new individuals is called sexual reproduction. During double fertilisation in angiosperms the haploid male gamete combines with two haploid polar nuclei to form a triploid primary endosperm nucleus by the process of vegetative fertilisation.

<span class="mw-page-title-main">In vitro fertilisation</span> Assisted reproductive technology procedure

In vitro fertilisation (IVF) is a process of fertilisation where an egg is combined with sperm in vitro. The process involves monitoring and stimulating a woman's ovulatory process, removing an ovum or ova from her ovaries and letting sperm fertilise them in a culture medium in a laboratory. After the fertilised egg (zygote) undergoes embryo culture for 2–6 days, it is transferred by catheter into the uterus, with the intention of establishing a successful pregnancy.

<span class="mw-page-title-main">Intracytoplasmic sperm injection</span> In vitro fertilization procedure

Intracytoplasmic sperm injection is an in vitro fertilization (IVF) procedure in which a single sperm cell is injected directly into the cytoplasm of an egg. This technique is used in order to prepare the gametes for the obtention of embryos that may be transferred to a maternal uterus. With this method, the acrosome reaction is skipped.

<span class="mw-page-title-main">Acrosome reaction</span> Sperm-meets-egg process

During fertilization, a sperm must first fuse with the plasma membrane and then penetrate the female egg cell to fertilize it. Fusing to the egg cell usually causes little problem, whereas penetrating through the egg's hard shell or extracellular matrix can be more difficult. Therefore, sperm cells go through a process known as the acrosome reaction, which is the reaction that occurs in the acrosome of the sperm as it approaches the egg.

<span class="mw-page-title-main">Human Fertilisation and Embryology Authority</span>

The Human Fertilisation and Embryology Authority (HFEA) is an executive non-departmental public body of the Department of Health and Social Care in the United Kingdom. It is a statutory body that regulates and inspects all clinics in the United Kingdom providing in vitro fertilisation (IVF), artificial insemination and the storage of human eggs, sperm or embryos. It also regulates human embryo research.

Insemination is the introduction of sperm into a female’s reproductive system for the purpose of impregnating, also called fertilizing, the female for sexual reproduction. The sperm is introduced into the uterus of a mammal or the oviduct of an oviparous (egg-laying) animal. In mammals, insemination normally occurs during sexual intercourse or copulation, but insemination can take place in other ways, such as by artificial insemination.

<span class="mw-page-title-main">Zona pellucida</span> Glycoprotein layer surrounding the plasma membrane of mammalian oocytes

The zona pellucida is a specialized extracellular matrix that surrounds the plasma membrane of mammalian oocytes. It is a vital constitutive part of the oocyte. The zona pellucida first appears in unilaminar primary oocytes. It is secreted by both the oocyte and the ovarian follicles. The zona pellucida is surrounded by the corona radiata. The corona is composed of cells that care for the egg when it is emitted from the ovary.

<span class="mw-page-title-main">Acrosin</span> Mammalian protein found in Homo sapiens

Acrosin is a digestive enzyme that acts as a protease. In humans, acrosin is encoded by the ACR gene. Acrosin is released from the acrosome of spermatozoa as a consequence of the acrosome reaction. It aids in the penetration of the Zona Pellucida.

<span class="mw-page-title-main">Assisted reproductive technology</span> Methods to achieve pregnancy by artificial or partially artificial means

Assisted reproductive technology (ART) includes medical procedures used primarily to address infertility. This subject involves procedures such as in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), cryopreservation of gametes or embryos, and/or the use of fertility medication. When used to address infertility, ART may also be referred to as fertility treatment. ART mainly belongs to the field of reproductive endocrinology and infertility. Some forms of ART may be used with regard to fertile couples for genetic purpose. ART may also be used in surrogacy arrangements, although not all surrogacy arrangements involve ART. The existence of sterility will not always require ART to be the first option to consider, as there are occasions when its cause is a mild disorder that can be solved with more conventional treatments or with behaviors based on promoting health and reproductive habits.

<span class="mw-page-title-main">Human fertilization</span> Union of a human egg and sperm

Human fertilization is the union of a human egg and sperm, occurring primarily in the ampulla of the fallopian tube. The result of this union leads to the production of a fertilized egg called a zygote, initiating embryonic development. Scientists discovered the dynamics of human fertilization in the nineteenth century.

<span class="mw-page-title-main">Human reproduction</span> Procreative biological processes of humanity

Human reproduction is sexual reproduction that results in human fertilization to produce a human offspring. It typically involves sexual intercourse between a sexually mature human male and female. During sexual intercourse, the interaction between the male and female reproductive systems results in fertilization of the ovum by the sperm to form a zygote. These specialized reproductive cells are called gametes, which are created in a process called gametogenesis. While normal cells contain 46 chromosomes, gamete cells only contain 23 single chromosomes, and it is when these two cells merge into one zygote cell that genetic recombination occurs and the new zygote contains 23 chromosomes from each parent, giving it 46 chromosomes. The zygote then undergoes a defined development process that is known as human embryogenesis, and this starts the typical 9-month gestation period that is followed by childbirth. The fertilization of the ovum may be achieved by artificial insemination methods, which do not involve sexual intercourse. Assisted reproductive technology also exists.

<span class="mw-page-title-main">Fertility clinic</span>

Fertility clinics are medical clinics that assist couples, and sometimes individuals, who want to become parents but for medical reasons have been unable to achieve this goal via the natural course. Clinics apply a number of diagnosis tests and sometimes very advanced medical treatments to achieve conceptions and pregnancies.

A humster is a hybrid cell line made from a hamster oocyte fertilized with human sperm. This is possible due to the unique promiscuity of hamster ova, which allows them to fuse with non-hamster sperm. It always consists of single cells, and cannot form a multi-cellular being. Humsters are usually destroyed before they divide into two cells; if isolated and left alone to divide, they would still be unviable.

Semen quality is a measure of male fertility, a measure of the ability of sperm in semen to accomplish fertilization. Semen quality involves both sperm quantity and quality. Semen quality is a major factor for fertility.

Pregnancy rate is the success rate for getting pregnant. It is the percentage of all attempts that leads to pregnancy, with attempts generally referring to menstrual cycles where insemination or any artificial equivalent is used, which may be simple artificial insemination (AI) or AI with additional in vitro fertilization (IVF).

Religious response to assisted reproductive technology deals with the new challenges for traditional social and religious communities raised by modern assisted reproductive technology. Because many religious communities have strong opinions and religious legislation regarding marriage, sex and reproduction, modern fertility technology has forced religions to respond.

<span class="mw-page-title-main">Fertility testing</span>

Fertility testing is the process by which fertility is assessed, both generally and also to find the "fertile window" in the menstrual cycle. General health affects fertility, and STI testing is an important related field.

Jacques Cohen is a Dutch embryologist based in New York, U.S. He is currently Director at Reprogenetics LLC, Laboratory Director at ART Institute of Washington at Walter Reed National Military Medical Center, and Scientific Director of R & D at IVF-online.

Antisperm antibodies (ASA) are antibodies produced against sperm antigens.

References

  1. ↑ Mortimer, David (1994). Practical laboratory andrology. New York: Oxford University Press. pp. 221–237. ISBN   9780195065954.
  2. ↑ Padubidri; Daftary (2011). Shaw's Textbook of Gynaecology, 15e. p. 204. ISBN   9788131225486
  3. ↑ Peterson, C. Matthew; Jones, Kirtly Parker; Hatasaka, Harry H.; Wong, Kenneth H. H. (October 2002). "Hamster Egg Penetration Test" (PDF). University of Utah Health Sciences Center. Utah Center for Reproductive Medicine. Archived from the original (PDF) on 22 Jan 2019. Retrieved 17 April 2013.
  4. ↑ Koulischer L, Debry JM (1989). "[The hamster test. Practical consequences]". Acta Urol Belg (in French). 57 (1): 77–81. PMID   2718849.
  5. ↑ Peterson et al. 2002: "The human sperm does not fertilize the hamster eggs."
  6. ↑ Bonnicksen, Andrea (2009). Chimeras, Hybrids, and Interspecies Research Politics and Policymaking. Georgetown University Press. p. 62. ISBN   9781589015746.
  7. ↑ Final Report of the Human Embryo Research Panel (Report). Bethesda, MD: National Institutes of Health. 27 September 1994. As cited in Bonnicksen 2009.
  8. ↑ "Human Fertilisation and Embryology Act 1990, Schedule 2, Section 1(1)(f)".
  9. ↑ Yang, YS; Rojas, FJ; Stone, SC (Dec 1988). "Acrosome reaction of human spermatozoa in zona-free hamster egg penetration test". Fertility and Sterility. 50 (6): 954–9. doi:10.1016/S0015-0282(16)60380-1. PMID   3203761.
  10. 1 2 Zainul Rashid, MR; Fishel, SB; Thornton, S; Hall, JA; Ndukwe, G; Aloum, M; Fleming, SD (Mar 1998). "The predictive value of the zona-free hamster egg penetration test in relation to in-vitro fertilization at various insemination concentrations". Human Reproduction (Oxford, England). 13 (3): 624–9. doi: 10.1093/humrep/13.3.624 . PMID   9572423.
  11. ↑ Osser, S; Wramsby, H; Liedholm, P (May–Jun 1988). "A comparison between the hamster egg penetration test and the seminal parameters in men of infertile couples". International Journal of Fertility. 33 (3): 207–11. PMID   2899568.
  12. ↑ Koulischer L, Debry JM (1989). "The hamster test. Practical consequences". Acta Urologica Belgica (in French). 57 (1): 77–81. PMID   2718849.
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