Human Leukocyte Antigen: From 1 Different Sources
(HLA) A type of protein belonging to the group known as histocompatibility antigens, which play a role in the immune system.
A substance, usually a protein, that induces the formation of defending antibodies. Example: bacterial toxins, Juniper pollen (in allergies). Auto-immune disorders can occur when antibodies are formed against normal proteins created within the body.... antigen
A glycoprotein hormone secreted by the PLACENTA in early pregnancy, and stimulating the CORPUS LUTEUM within the ovary (see OVARIES) to secrete OESTROGENS, PROGESTERONE, and relaxin. The hormone is essential for the maintenance of pregnancy up to about 6–8 weeks of gestation. A RADIOIMMUNOASSAY can be used to detect its presence, and pregnancy can be diagnosed as early as six days after conception by testing for it in the urine. Some tumours also secrete human chorionic gonadotrophin, particularly HYDATIDIFORM MOLE, which produces large amounts.... human chorionic gonadotrophin
In simple terms, this is the genetic recipe for making a human being. GENOME is a combination of the words gene and chromosome, and a genome is de?ned as all the genetic material – known as deoxyribonucleic acid, or DNA – in a cell. Most genes encode sequences of AMINO ACIDS, the constituents of proteins, thus initiating and controlling the replication of an organism. The identi?cation and characterisation of the human genetic puzzle have been a key bioscience research target. The Human Genome Project was launched in 1990 (and completed in 2003) to produce a full sequence of the three million base pairs that make up the human genome.
Carried out as two separate exercises – one by a privately funded American team; another by an international joint venture between tax-funded American laboratories, a charitably funded British one and several other smaller research teams from around the world – the ?rst results were announced on 26 June 2000. In February 2001 the privately funded American group, known as Celera Genomics, announced that it had identi?ed 26,558 genes. At the same time the Human Genome Project consortium reported that it had identi?ed 31,000. Allowing for margins of error, this gives a ?gure much lower than the 100,000 or more human genes previously forecast by scientists. Interestingly, genes were found to make up only 3 per cent of the human genome. The remaining 97 per cent of the genome comprises non-coding DNA which, though not involved in producing the protein-initiating genetic activity, does have signi?cant roles in the structure, function and evolution of the genome.
One surprise from the Project so far is that the genetic di?erences between humans and other species seem much smaller than previously expected. For example, the Celera team found that people have only 300 genes that mice do not have; yet, the common ancestor of mice and men probably lived 100 million years or more in the past. Mice and humans, however, have around twice as many genes as the humble fruit ?y.
Cells die out when they become redundant during embryonic development: genes also die out during evolution, according to evidence from the Genome Project – a ?nding that supports the constant evolutionary changes apparent in living things; the Darwinian concept of survival of the ?ttest.
Apart from expanding our scienti?c knowledge, the new information – and promise of much more as the Genome Project continues – should enhance and expand the use of genetic engineering in the prevention and cure of disease. Studies are in progress on the gene for a receptor protein in the brain which will shed light on how the important neurotransmitter SEROTONIN in the brain works, and this, for example, should help the development of better drugs for the treatment of DEPRESSION. Another gene has been found that is relevant to the development of ASTHMA and yet another that is involved in the production of amyloid, a complex protein which is deposited in excessive amounts in both DOWN’S (DOWN) SYNDROME and ALZHEIMER’S DISEASE.... human genome
The name of the causative agent of AIDS.... hiv (human immunodeficiency virus)
Human skills and capabilities generated by investments in education and health.... human capital
A composite index that measures the overall achievements in a country in three basic dimensions of human development— longevity, knowledge and a decent standard of living. It is measured by life expectancy, educational attainment and adjusted income per capita in purchasing power parity (PPP) US dollars. The HDI is a summary, not a comprehensive measure of human development.... human development index (hdi)
See ASSISTED CONCEPTION.... human fertilisation & embryology act 1990
See ASSISTED CONCEPTION.... human fertilisation & embryology authority (hfea)
See AIDS/HIV.... human immunodeficiency virus
See HLA SYSTEM.... human leucocyte antigen (hla)
UK legislation that lays down the framework and rules governing organ transplantation. The UK Transplant Support Service Authority (UKTSSA), a special health authority set up in 1991, is responsible for administering the NHS Organ Donor Registry and the Act (see APPENDIX 7: STATUTORY ORGANISATIONS).... human organs transplants act
The study of the interrelationships between humans, the tools they use, and the environment in which they live and work.... human-factor research
Substances, usually harmful, that when entering the body stimulate the immune system to produce antibodies. Invaders may be polio virus, typhoid bacillus, or chain-like streptococcal bacteria – the usual pus-forming type found in infected wounds, or toxins they release into the blood stream. ... antigens
Creutzfeldt-Jakob disease. See: BOVINE SPONGIFORM ENCEPHALOPATHY. ... mad-cow disease, human
An ENZYME produced by glandular tissue in the PROSTATE GLAND. When the gland enlarges (see PROSTATE, DISEASES OF), greater amounts of PSA are secreted, raising the concentration of the enzyme in the blood. This is especially so in cancer of the prostate, and testing the level of PSA is an indicator that the disease may be present. There is much controversy about the use of PSA as a screening test. Its proponents claim that its use reduces deaths from prostate cancer; its opponents suggest that it does this only by bringing to light many cases that needed no treatment and would not have caused death in any case. Further, if the level of PSA is very high, the disease is already advanced; where the result is equivocal it is uncertain whether the bene?ts of treatment outweigh the risks.... prostate specific antigen (psa)
Wounds caused by one person biting another. Human bites rarely cause serious tissue damage or blood loss, but infection is likely, particularly if the bite is deep. There is a risk of tetanus infection. Transmission of hepatitis B, herpes simplex, and AIDS by a bite is a theoretical hazard.... bites, human
The complete set of human genetic material. The human genome consists of 23 chromosomes, which, together, contain about 30,000 genes. All body cells contain 2 sets of the 23 chromosomes, one set inherited from the father and the other from the mother. An international research programme, the Human Genome Project, was launched in 1990 with the aim of identifying all the human genes. The first rough draft of the project was published in 2000.... genome, human
A hormone produced by the placenta in early pregnancy. Human chorionic gonadotrophin (HCG) stimulates the ovaries to produce oestrogen and progesterone, which are needed for a healthy pregnancy. HCG is excreted in the urine, and its presence in urine is the basis of pregnancy tests on urine samples. ... gonadotrophin, human chorionic
Any type of white blood cell.... leukocyte
(APC) a cell, such as a *dendritic cell or a *macrophage, that processes antigen for presentation to a T lymphocytes (see helper T cell).... antigen-presenting cell
another name for the *hepatitis B antigen, which was first discovered in the blood of an Australian aborigine. This disease is caused by a virus of which the Australia antigen forms part.... australia antigen
(CEA) a protein produced in the fetus but not in normal adult life. It may be produced by carcinomas, particularly of the colon, and is a rather insensitive marker of malignancy. It is an example of an *oncofetal antigen that is used as a *tumour marker, particularly in the follow-up of colorectal cancer.... carcino-embryonic antigen
(HHS) the major US government agency providing health care. The department was created in 1953 and assumed its current name in 1980. HHS administers more than 300 health and health-related programmes and services, including *Medicare and *Medicaid. Other activities include research, immunization services, and providing financial assistance for low-income families. Almost a quarter of federal spending occurs through HHS.... department of health and human services
a nondepartmental public body set up in 2007 to promote human rights and equality in regard to age, disability, gender, race, religion and belief, pregnancy and maternity, marriage and civil partnership, sexual orientation, and human rights. It replaced the Commission for Racial Equality, the Disability Rights Commission, and the Equal Opportunities Commission.... equality and human rights commission
see human placental lactogen.... human chorionic somatomammotrophin
Acts of the UK parliament in 1990 and 2008, establishing and amending principles for the legal supervision, by the Human Fertilisation and Embryology Authority, of the creation, use, and storage of human embryos outside the body and of their use in treatment and research. The 2008 amendments included a ban on sex selection for social reasons, recognition of same-sex couples as potential legal parents, and regulations related to developing areas of research using embryos. The 1990 Act had also reduced the legal time limit for most abortions from 28 weeks gestation (as in the 1967 Abortion Act) to 24 weeks. Interpretation and regulation of principles and practice in this rapidly developing area of research and practice continue and are often controversial.... human fertilisation and embryology acts
a massive international research project to isolate all the genes in human DNA and determine the sequence of genes on human chromosomes. The project began in 1988 and the full draft sequence was published in 2001; the high-quality sequence was completed in 2003. The human genome comprises some 3 × 109 nucleotide base pairs (see DNA) forming 22,000–25,000 genes, distributed among 23 pairs of chromosomes. Knowledge of the entire human genome has already resulted in the identification of the genes associated with many hereditary disorders and revealed the existence of a genetic basis or component for many other diseases not previously known to have one. Theoretically, this would enable the development of targeted drugs and the large-scale genetic screening of populations. See pharmacogenomics; targeted agent.... human genome project
see HIV.... human immunodeficiency virus
see HLA system.... human leucocyte antigen system
commercially available preparations of *follicle-stimulating hormone and *luteinizing hormone. They are used mainly to treat infertility in women with gonadotrophin deficiency due to hypopituitarism and to stimulate superovulation in women undergoing in vitro fertilization.... human menopausal gonadotrophins
(human chorionic somatomammotrophin) a protein hormone of 190 amino acids produced by the placenta during most but not all pregnancies. Despite its name it does not appear to have a role in lactation and its exact function remains obscure. It does, however, seem to contribute to the development of diabetes in some pregnancies.... human placental lactogen
a legal framework adopted by the United Nations following World War II that sought to define and promote fundamental entitlements, conditions, and freedoms to be afforded to all human beings. In the UK the Human Rights Act 1998 enacts the provisions of the 1950 European Convention on Human Rights, which sets out, via fourteen articles, an individual’s rights, entitlements, and freedoms.... human rights
the UK government agency, established by the Human Tissue Act 2004, that regulates the removal, use, and storage of human organs and tissue from both the living and the deceased for certain purposes as defined by the statute. These purposes include clinical research, clinical audit, and medical education. Anyone handling such material for those purposes should have a licence issued by the authority. Membership of the authority comprises clinical, scientific, academic, and lay representatives.... human tissue authority
a group of antigens that may or may not be present on the surface of red blood cells, forming the basis of a *blood group. This group is important in blood transfusion reactions. [Mrs Kell (20th century), patient in whom they were first demonstrated]... kell antigens
a protein normally produced only by fetal tissue but often produced by certain tumours. An example is *carcino-embryonic antigen (CEA), which has been used as a *tumour marker, especially in colorectal carcinomas.... oncofetal antigen
a protein produced by cancer cells. Its presence in the blood can be revealed by means of a simple blood test, aiding the diagnosis of malignant melanoma and other cancers at their earliest – and most treatable – stages of development.... tumour-associated antigen
(PSA) a protease enzyme produced by the glandular epithelium of the prostate. Its effect is to liquefy the semen within the ejaculate. Overall PSA has a half-life of 2–3 days. Increased quantities are secreted when the gland becomes enlarged or inflamed, and levels of PSA in the blood are significantly elevated in cancer of the prostate. Although there is no clear ‘cut-off’ level for normality, over 4 ng/ml in the blood is associated with a 20% risk of prostate cancer, even in patients with normal-feeling prostates on rectal examination. Age-specific PSA reference ranges are often used. Newer PSA assays can measure free PSA and compare it to the total PSA in the blood. Low free:total PSA ratios indicate a greater risk of prostate cancer and improve the discrimination between cancer and benign disease in men with a PSA in the range 4–10 ng/ml. PSA levels tend to be much higher in advanced prostate cancer and the rate of fall on treatment (e.g. after radical prostatectomy or radiotherapy) is a good prognostic indicator of response.... prostate specific antigen
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