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Mixed Antiglobulin Reaction
Antisperm antibodies (ASA) are antibodies produced against sperm antigens. Types Antisperm antibodies are immunoglobulins of IgG, IgA, and/or IgM, which are directed against sperm antigens. ASA can be detected in ejaculate, cervical mucus, follicular fluid, and blood serum of both males and females. While IgG and IgA might be present in blood serum and/or genital tract fluids, IgM is only present in blood serum. IgG occurring in genital tract fluids is either produced locally or transuded from blood serum, whereas IgA (secretory type) is always produced locally. Causes Traditionally, the breakdown of the blood-testis barrier had been established as the cause of ASA production. This mechanism had been advocated in testicular trauma and surgery, orchitis (mumps), varicocele, bacterial infections (epididymitis, prostatitis), testicular cancer, and unprotected anal intercourse. However, the association between aforementioned conditions and ASA production is controversial. Only ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antibodies
An antibody (Ab) or immunoglobulin (Ig) is a large, Y-shaped protein belonging to the immunoglobulin superfamily which is used by the immune system to identify and neutralize antigens such as bacteria and viruses, including those that cause disease. Each individual antibody recognizes one or more specific antigens, and antigens of virtually any size and chemical composition can be recognized. Antigen literally means "antibody generator", as it is the presence of an antigen that drives the formation of an antigen-specific antibody. Each of the branching chains comprising the "Y" of an antibody contains a paratope that specifically binds to one particular epitope on an antigen, allowing the two molecules to bind together with precision. Using this mechanism, antibodies can effectively "tag" the antigen (or a microbe or an infected cell bearing such an antigen) for attack by cells of the immune system, or can neutralize it directly (for example, by blocking a part of a viru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phagocytosis
Phagocytosis () is the process by which a cell (biology), cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis is called a phagocyte. In a Multicellular organism, multicellular organism's immune system, phagocytosis is a major mechanism used to remove pathogens and cell debris. The ingested material is then digested in the phagosome. Bacteria, dead tissue cells, and small mineral particles are all examples of objects that may be phagocytized. Some protozoa use phagocytosis as means to obtain nutrients. The two main cells that do this are the Macrophages and the Neutrophils of the immune system. Where phagocytosis is used as a means of feeding and provides the organism part or all of its nourishment, it is called phagotrophy and is distinguished from osmotrophy, which is nutrition taking place by absorption. History The history of phag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infertility
In biology, infertility is the inability of a male and female organism to Sexual reproduction, reproduce. It is usually not the natural state of a healthy organism that has reached sexual maturity, so children who have not undergone puberty, which is the body's start of fertility, reproductive capacity, are excluded. It is also a normal state in women after menopause. In humans, ''infertility'' is defined as the inability to become pregnant after at least one year of unprotected and regular sexual intercourse involving a male and female partner. There are many causes of infertility, including some that Assisted reproductive technology, medical intervention can treat. Estimates from 1997 suggest that worldwide about five percent of all heterosexual couples have an unresolved problem with infertility. Many more couples, however, experience involuntary childlessness for at least one year, with estimates ranging from 12% to 28%. Male infertility is responsible for 20–30% of infert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postcoital Test
The postcoital test (PCT), also known as the Sims test, Hühner test ,Sims–Hühner test, or cervical mucous penetration assay is a test in the evaluation of infertility. The test examines interaction between sperm and mucus of the cervix. The PCT examines sperm survival in cervical mucus during the pre-ovulatory period and determines whether sperm are migrating into the female reproductive system. It does not predict whether pregnancy can occur. The test is performed 1 to 2 days before ovulation, when estrogen-stimulated cervical mucus is abundant. Basal body temperatures or the midcycle luteinizing hormone surge may be used to determine the timing of the PCT. Mucus is withdrawn from the endocervical canal within 8 hours of coitus and examined. The presence of any forwardly motile sperm in alkaline mucus suggests adequate coital technique and a normal cervical mucus–sperm interaction. Procedure The PCT is scheduled close to ovulation when mucus is abundant, and the infertile c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azoospermia
Azoospermia is the medical condition of a man whose semen contains no sperm. It is associated with male infertility, but many forms are amenable to medical treatment. In humans, azoospermia affects about 1% of the male population and may be seen in up to 20% of male infertility situations in Canada. In a non-pathological context, azoospermia is also the intended result of a vasectomy. Classification Azoospermia can be classified into three major types. Many conditions listed may also cause various degrees of oligospermia rather than azoospermia. Pretesticular and testicular azoospermia are known as non-obstructive azoospermia, whereas post-testicular azoospermia is considered obstructive. Pretesticular Inadequate stimulation of normal testicles and the genital tract characterizes pretesticular azoospermia. Typically, follicle-stimulating hormone (FSH) levels are low (hypogonadotropic), commensurate with inadequate stimulation of the testes to produce sperm. Examples include ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oligospermia
Terms oligospermia, oligozoospermia, and low sperm count refer to semen with a low concentration of sperm and is a common finding in male infertility. Often, semen with a decreased sperm concentration may also show significant abnormalities in sperm morphology and motility (technically oligoasthenoteratozoospermia). There has been interest in replacing the descriptive terms used in semen analysis with more quantitative information. Diagnosis The diagnosis of oligozoospermia is based on one low count in a semen analysis performed on two occasions. For many decades sperm concentrations of less than 20 million sperm/ml were considered low or oligospermic, recently, however, the WHO reassessed sperm criteria and established a lower reference point, less than 15 million sperm/ml, consistent with the 5th percentile for fertile men. Sperm concentrations fluctuate daily, and oligozoospermia may be temporary or permanent. The diagnosis of oligozoospermia requires a work-up via semen analy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agglutination (biology)
Agglutination is the clumping of particles. The word ''agglutination'' comes from the Latin '' agglutinare'' (glueing to). Agglutination is a reaction in which particles (as red blood cells or bacteria) suspended in a liquid collect into clumps usually as a response to a specific antibody. This occurs in biology in two main examples: # The clumping of cells such as bacteria or red blood cells in the presence of an antibody or complement. The antibody or other molecule binds multiple particles and joins them, creating a large complex. This increases the efficacy of microbial elimination by phagocytosis as large clumps of bacteria can be eliminated in one pass, versus the elimination of single microbial antigens. # When people are given blood transfusions of the wrong blood group, the antibodies react with the incorrectly transfused blood group and as a result, the erythrocytes clump up and stick together causing them to agglutinate. The coalescing of small particles that are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monospecific Antibody
Monospecific antibodies are antibodies whose specificity to antigens is singular (''mono-'' + ''specific'') in any of several ways: antibodies that all have affinity for the same antigen; antibodies that are specific to one antigen or one epitope; or antibodies specific to one type of cell or tissue. Monoclonal antibodies are monospecific, but monospecific antibodies may also be produced by other means than producing them from a common germ cell. Regarding antibodies, ''monospecific'' and ''monovalent'' overlap in meaning; both can indicate specificity to one antigen, one epitope, or one cell type (including one microorganism species). However, antibodies that are monospecific to a certain tissue, or all monospecific to the same tissue because clones, can be polyvalent in their epitope binding. Production Hybridoma cell Monoclonal antibodies are typically made by fusing the spleen cells from a mouse that has been immunized with the desired antigen with myeloma cells. However, rece ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Blood Cell
Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood cell and the vertebrate's principal means of delivering oxygen () to the body tissue (biology), tissues—via blood flow through the circulatory system. Erythrocytes take up oxygen in the lungs, or in fish the gills, and release it into tissues while squeezing through the body's capillary, capillaries. The cytoplasm of a red blood cell is rich in hemoglobin (Hb), an iron-containing biomolecule that can bind oxygen and is responsible for the red color of the cells and the blood. Each human red blood cell contains approximately 270 million hemoglobin molecules. The cell membrane is composed of proteins and lipids, and this structure provides properties essential for physiological Cell (biology), cell function such as erythrocyte deformabil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coombs Test
The direct and indirect Coombs tests, also known as antiglobulin test (AGT), are blood tests used in immunohematology. The direct Coombs test detects antibodies that are stuck to the surface of the red blood cells. Since these antibodies sometimes destroy red blood cells they can cause anemia; this test can help clarify the condition. The indirect Coombs test detects antibodies that are floating freely in the blood. These antibodies could act against certain red blood cells; the test can be carried out to diagnose reactions to a blood transfusion. The direct Coombs test is used to test for autoimmune hemolytic anemia, a condition where the immune system breaks down red blood cells, leading to anemia. The direct Coombs test is used to detect antibodies or complement system, complement proteins attached to the surface of red blood cells. To perform the test, a blood sample is taken and the red blood cells are washed (removing the patient's plasma and unbound antibodies from the red b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryo
An embryo ( ) is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell. The resulting fusion of these two cells produces a single-celled zygote that undergoes many cell divisions that produce cells known as blastomeres. The blastomeres (4-cell stage) are arranged as a solid ball that when reaching a certain size, called a morula, (16-cell stage) takes in fluid to create a cavity called a blastocoel. The structure is then termed a blastula, or a blastocyst in mammals. The mammalian blastocyst hatches before implantating into the endometrial lining of the womb. Once implanted the embryo will continue its development through the next stages of gastrulation, neurulation, and organogenesis. Gastrulation is the formation of the three germ layers that will form all of the different parts of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fertilisation
Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a zygote and initiate its development into a new individual organism or offspring. 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. History In antiquity, Aristotle conceived the formation of new individuals through fusion of male and female fluids, with form and function emerging gradually, in a mode called by him as epigenetic. In 1784, Spallanzani established the need of in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
