The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
Signs and symptoms of higher cortical dysfunction caused by organic conditions. These include certain behavioral alterations and impairments of skills involved in the acquisition, processing, and utilization of knowledge or information.
Implants used to reconstruct and/or cosmetically enhance the female breast. They have an outer shell or envelope of silicone elastomer and are filled with either saline or silicone gel. The outer shell may be either smooth or textured.
Implants used to reconstruct and/or cosmetically enhance the female breast. They have an outer shell or envelope of silicone elastomer and are filled with either saline or silicone gel. The outer shell may be either smooth or textured.
Filament or fiber, or the materials generated from them by weaving, embroidery, knitting, crocheting, tufting, or felting such as yarn, thread, cording, rope, netting, lace, or sheets of cloth or fabric.
Classes of retroviruses for which monkeys or apes are hosts. Those isolated from the West African green monkey and the Asian rhesus macaque monkey are of particular interest because of their similarities to viruses causing cancer and acquired immunodeficiency syndrome (AIDS) in humans.
A natural, adoptive, or substitute parent of a dependent child, who lives with only one parent. The single parent may live with or visit the child. The concept includes the never-married, as well as the divorced and widowed.
A method of computed tomography that uses radionuclides which emit a single photon of a given energy. The camera is rotated 180 or 360 degrees around the patient to capture images at multiple positions along the arc. The computer is then used to reconstruct the transaxial, sagittal, and coronal images from the 3-dimensional distribution of radionuclides in the organ. The advantages of SPECT are that it can be used to observe biochemical and physiological processes as well as size and volume of the organ. The disadvantage is that, unlike positron-emission tomography where the positron-electron annihilation results in the emission of 2 photons at 180 degrees from each other, SPECT requires physical collimation to line up the photons, which results in the loss of many available photons and hence degrades the image.
A treatment program based on manipulation of the patient's environment by the medical staff. The patient does not participate in planning the treatment regimen.
A specialized CONNECTIVE TISSUE that is the main constituent of the SKELETON. The principal cellular component of bone is comprised of OSTEOBLASTS; OSTEOCYTES; and OSTEOCLASTS, while FIBRILLAR COLLAGENS and hydroxyapatite crystals form the BONE MATRIX. --consider also terms at OSSI- OSTE-
