Platelet-derived growth factor Health Dictionary

One of two proteins secreted from the lining of the stomach whose sole purpose is (it seems) to cradle B12 in a pre-fitted styrofoam mold and (A) carry it through the Seven Levels of Digestive Hell until it reaches those few absorption sites in the last foot of small intestine that understand its “Special Needs” (sounds either sexually kinky or the airplane dinner label on kosher food for flying Hassidim jewelers) and finally (B) slip it from one protein to the other, and thence into the cell membranes where its is turn handed over to (C) the specialized blood protein that can carry it safely to the final target tissues (3 times out of 4, the bone marrow). Cyanocobalamin (B12) has parts that fall off, radicals that twirl around in five directions on three charge potentials, and is as durable as a 49¢ water pistol. And, if we have an ulcer, chronic enteritis or long-standing steatorrhea, we either get B12 shots (and hope the liver still makes that blood carrier) or walk around with pernicious anemia and a hematocrit of 16.... intrinsic factor

An aspect of personal behaviour or lifestyle, an environmental exposure, or an inborn or inherited characteristic, which, on the basis of scientific evidence, is known to be associated with health-related condition(s) considered important to prevent.... risk factor

A coagulative blood protein that is a constituent of the COAGULATION cascade – an essential component in the clotting of blood. Those people with the inherited disorder, HAEMOPHILIA, have abnormally low amounts of factor VIII and so bleed more when cut. They are treated with a concentrated version to reduce the tendency to bleed.... factor viii

A product of the anterior part of the PITUITARY GLAND that promotes normal growth and development in the body by changing the chemical activity in the cells. The hormone activates protein production in the muscle cells as well as the release of energy from the metabolism of fats. Its release is controlled by the contrasting actions of growth-hormone releasing factor and somatostatin. If the body produces too much growth hormone before puberty GIGANTISM results; in adulthood the result is ACROMEGALY. Lack of growth hormone in children retards growth.

For many years growth hormone was extracted from human corpses and very rarely this caused CREUTZFELDT-JAKOB DISEASE (CJD) in the recipients. The hormone is now genetically engineered, so safe.... growth hormone

A popular term applied to any new formation in any part of the body. (See CANCER; CYSTS; GANGLION; TUMOUR.) For growth of children, see WEIGHT AND HEIGHT.... growth

See BLOOD GROUPS.... rh factor

See BLOOD GROUPS.... rhesus factor

A protein in blood that plays an important role in the clotting mechanism. A deficiency of factor causes a rare genetic bleeding disorder known as Christmas disease.... factor ix

Any of various chemicals involved in stimulating new cell growth and maintenance.

Some growth factors, such as vascular endothelial growth factor, which stimulates the formation of new blood vessels, are important in the growth and spread of cancers.... growth factor

The smallest type of blood cell, also called a thrombocyte. Platelets play a major role in blood clotting.... platelet

A chemical, psychological, physiological, social, environmental or genetic factor or conditions that predisposes an individual to the development of a disease or injury.... health risk factor

The study of the interrelationships between humans, the tools they use, and the environment in which they live and work.... human-factor research

An agent involved in the clotting mechanism of the blood. It helps in the activation of THROMBOPLASTIN in the blood PLASMA (see COAGULATION).... lipoid factor

Various compounds and processes that enable the liver to metabolize fats properly or prevent the formation of cholesterolic stones in the gall bladder by supporting the continued emulsification of gall bladder bile. EXAMPLES: Lecithin, choline, Aristolochia... lipotropic factors

Platelets are the small, rather uniform fragments of large bone marrow cells that aid the blood in coagulation, hemostasis, inflammation, and thrombus formation. Mild subclotting and sticking is a common early condition that can lead to thrombosis, atherosclerosis, and strokes, and can be helped by an aspirin a day, better fat digestion, and Ceanothus.... platelet aggregation

The clumping together of platelets (small, sticky blood particles). Aggregation is the 1st stage of blood clotting and helps to plug injured vessels. Inappropriate aggregation can have adverse effects; for example, if aggregation occurs in an artery, it may result in a thrombosis.... aggregation, platelet

One of the blood proteins that maintains the balance between the blood clotting too easily or too slowly after an injury.

About 5 per cent of the population have an inherited mutation in the gene controlling factor V production, known as factor V Leiden.

They are at increased risk of deep-vein thrombosis (see thrombophilia), particularly if they are taking the oral contraceptive pill or go on long aircraft journeys.... factor v

Poor growth in a fetus, usually resulting from a failure of the placenta to provide adequate nutrients (often related to pre-eclampsia) or sometimes from a fetal defect. Severe maternal disease, such as chronic kidney failure, can reduce fetal growth. Fetal problems such as an intrauterine infection or genetic disorder can also impair growth. Smoking during pregnancy may reduce fetal growth and birth weight.

Intrauterine growth retardation may be suspected on antenatal examination;... intrauterine growth retardation

The increase in height and weight as a child develops. The period of most rapid growth occurs before birth. After birth, although growth is still rapid in the first few years of life, especially in the first year, the rate of

growth steadily decreases. Puberty marks another major period of growth, which continues until adult height and weight are reached, usually at about age 16–17 in girls and 19–21 in boys.

Body shape changes during childhood because different areas grow at different rates. For example, at birth, the head is already about three quarters of its adult size; it grows to almost full size during the first year. Thereafter, it becomes proportionately smaller because the body grows at a much faster rate.

Growth can be influenced by heredity and by environmental factors such as nutrition and general health. Hormones also play an important role, particularly growth hormone, thyroid hormones, and, at puberty, the sex hormones.

A chronic illness, such as cystic fibrosis, may retard growth. Even a minor illness can slow growth briefly, although the growth rate usually catches up when the child recovers. In some cases, slow growth may be the only sign that a child is ill or malnourished, in which case it is known as failure to thrive. However, short stature does not necessarily indicate poor health. Abnormally rapid growth is rare. Usually, it is a familial trait, but it may occasionally indicate an underlying disorder, such as a pituitary gland tumour causing gigantism. (See also age; child development.)... growth, childhood

Factors that lead to increased susceptibility to a disease.... predisposing factors

A group of hormones, produced by the hypothalamus in the brain, that stimulates the release of other hormones.

Luteinizing hormone-releasing hormone is one such releasing factor.... releasing factors

a group of *growth factors that promote new bone formation. Bone morphogenic protein (BMP), a naturally occurring substance that induces *osteoblast formation, has been genetically synthesized to form bone morphogenetic protein, which stimulates new bone formation and assists with fracture healing. Other bone growth factors include a type of transforming growth factor (TGF?) and insulin-like growth factor II (IGF-II), which encourage collagen formation.... bone growth factors

see coagulation factors.... clotting factors

(clotting factors) a group of substances present in blood plasma that, under certain circumstances, undergo a series of chemical reactions leading to the conversion of blood from a liquid to a solid state (see blood coagulation). Although they have specific names, most coagulation factors are referred to by an agreed set of Roman numerals (e.g. *Factor VIII, *Factor IX). Lack of any of these factors in the blood results in the inability of the blood to clot. See also haemophilia.... coagulation factors

(CSF) one of a group of substances (haemopoietic growth factors or hormones) that are produced in the bone marrow and stimulate the production of specific blood cells. Genetically engineered granulocyte colony-stimulating factor (G-CSF) stimulates neutrophil production and also limits bone marrow toxicity from chemotherapy.... colony-stimulating factor

(EGFR) a protein on the surface of cells (see receptor) that binds with epidermal *growth factor and is therefore involved in cell division. EGFR is expressed at increased levels in numerous tumours, particularly of the head and neck, and in colorectal cancer, in which it can be a target for antibody therapy with *cetuximab. *Tyrosine kinase inhibitors acting specifically on the EGFR include gefitinib and erlotinib in lung and pancreatic cancer.... epidermal growth factor receptor

n. (in biochemistry) a substance that is essential to a physiological process, often a substance the nature of which is unknown. See also coagulation factors; growth factor.... factor

an inherited mutation in the gene coding for coagulation Factor V, which results in an increased susceptibility to develop venous *thrombosis.... factor v leiden

a *coagulation factor normally present in blood. Deficiency of the factor is inherited, but rarely causes spontaneous bleeding. However, bleeding does occur after surgery or trauma to the blood vessels.... factor xi

a graph, customized to a pregnant woman’s height, weight, and other factors, that plots *fundal height and estimated fetal weight on ultrasound against weeks of gestation. The graph, which shows centile lines (see centile chart), improves prediction of a baby who is *small for gestational age.... fetal growth chart

see intrauterine growth restriction.... fetal growth restriction

see physis.... growth plate

(IUGR, fetal growth restriction) failure of a fetus to achieve its growth potential, resulting in the birth of a baby whose birth weight is abnormally low in relation to its gestational age (see small for gestational age). Causes include *uteroplacental insufficiency, maternal disease (e.g. infection, malnutrition, high blood pressure, smoking, and alcoholism), poor socioeconomic conditions, multiple pregnancy (e.g. twins), and fetal disease or chromosomal abnormalities. It may be associated with *preterm birth.... intrauterine growth restriction

(NGF) a protein (see growth factor), consisting of two polypeptide chains, that is required for the development and longevity of some neurons, including those in the sympathetic nervous system and some central nervous system and sensory neurons. Nerve growth factor is necessary for axon growth and also for initiating new neuronal connections with other cells. The role of NGFs in preventing the degeneration of brain cells is being explored in research into Alzheimer’s disease.... nerve growth factor

the process whereby platelets adhere to collagen released from endothelial cells in damaged blood vessels and aggregate to form a plug. An important metabolic pathway in platelets converts membrane phospholipids to *thromboxane A2 (TXA2), which can activate platelets. ADP, released from platelet granules, and *thrombin are other activators. The adhesive and aggregation reactions of platelets are mediated through surface membrane glycoproteins (Glp), Glp Ib and Glp IIb/IIIa. Aspirin acts as an *antiplatelet drug by irreversibly inhibiting one of the enzymes of this pathway, cyclo-oxygenase. Clopidrogel inhibits the ADP receptor on platelet membranes, and *abciximab blocks platelet aggregation by inhibiting Glp IIb/IIIa (see illustration overleaf).... platelet activation

(TGF) a protein – a *cytokine – that controls growth, proliferation, and other functions in most cells. It plays a role in asthma and other respiratory diseases and is also involved in diseases elsewhere in the body. There are two classes: TGF-? and TGF-?.... transforming growth factor

(TNF) either of two proteins, TNF-? or TNF-?, that function as *cytokines. Produced by macrophages, monocytes, T lymphocytes, and various other cells, they mediate many responses, including inflammation, and have a marked action against tumour cells. Anti-TNF drugs (see cytokine inhibitor) are used in the treatment of several disorders, especially rheumatoid arthritis and ankylosing spondylitis.... tumour necrosis factor

(VEGF) a *growth factor made by both normal cells and their abnormal or malignant counterparts to stimulate new blood vessel formation (see angiogenesis). It can be targeted by a family of drugs known as *angiogenesis inhibitors, which include *bevacizumab.... vascular endothelial growth factor