Cyto-: From 2 Different Sources
A prefix that means related to a cell, as in cytology, the study of cells.
A pre?x meaning something connected with a cell or CELLS.
Study of cells removed from surface of organs (exfoliated cells) for the purpose of diagnosing cancer; e.g., Papanicolaou smear.... cytology
The study of the structure and functions of the cells of the body, with particular reference to the CHROMOSOMES.... cytogenetics
Also lymphokine, a broad term for a variety of proteins and neuropeptides that lymphocytes and macrophages use to communicate between themselves, often from long distances. They stimulate organization and antibody responses, seem to induce the bone marrow to proliferate the type of white blood cells needed for immediate resistance, and generate sophistication and fine tuning for an overall strategy of resistance. A lymphocyte FAX.... cytokine
A family of PROTEIN molecules that carry signals locally between cells. Cytokines are released by cells when activated by antigens (see ANTIGEN), behaving as enhancing mediators for immune response. These proteins include INTERLEUKINS (produced by LEUCOCYTES), lymphokines (produced by lymphocytes – see LYMPHOCYTE), INTERFERON, and tumour necrosis factor, one of whose many functions is killing tumour cells.... cytokines
An instrument for counting and measuring CELLS.... cytometer
The PROTOPLASM of the cell body. (See CELLS.)... cytoplasm
Chemicals used to kill cancerous cells. Most cytotoxic drugs also kill normal cells. There is a delicate balance between killing enough cancer cells and not so many normal cells.... cytotoxic drugs
One of the most common herpes viruses, which causes infected cells to take on an enlarged appearance. Cytomegalovirus (CMV) infection may cause an illness resembling infectious mononucleosis, but usually produces no symptoms. People who have impaired immunity are more seriously infected. A pregnant woman can transmit the virus to her unborn child; this can cause birth defects and brain damage in the child.... cytomegalovirus
Cytotoxic means destructive to living cells. Cytotoxic drugs possess anti-cancer properties but also have the potential to damage normal tissue. Their use is twofold: to eliminate a cancer and so prolong life; or to alleviate distressing symptoms, especially in patients whose prospects of a cure are poor. In many cases CHEMOTHERAPY with cytotoxic drugs is combined with surgery, RADIOTHERAPY or both. Chemotherapy may be used initially to reduce the size of the primary TUMOUR (a process called neoadjuvant therapy) before using radiotherapy or surgery to eliminate it. Cytotoxic drugs may also be used as adjuvant treatment to prevent or destroy secondary spread of the primary tumour that has either been removed by surgery or treated with radiotherapy. All chemotherapy causes side-effects: the ONCOLOGIST – a specialist in cancer treatment – has to strike a balance between hoped-for bene?ts and acceptable (for the patient) toxic effects, which include nausea and vomiting, BONE MARROW suppression, ALOPECIA (hair loss) and teratogenic effects (see TERATOGENESIS).
Cytotoxic drugs are used either singly or in combination, when an enhanced response is the aim. Chemotherapy of cancer is a complex process and should be supervised by an oncologist in co-operation with physicians, surgeons, radiotherapists and radiologists as appropriate.
The cytotoxic drugs include:
(1) The alkylating agents which act by damaging DNA, thus interfering with cell reproduction. Cyclophosphamide, ifosfamide, chlorambucil, kelphalan, busulphan, thiotepa and mustine are examples of alkylating agents.
(2) There are a number of cytotoxic antibiotics used in the treatment of cancer – doxorubicin, bleomycin, dactinomycin, mithramycin and amsacrine are examples. They are used primarily in the treatment of acute leukaemia and lymphomas.
(3) Antimetabolites – these drugs combine irreversibly with vital enzyme systems of the cell and hence prevent normal cell division. Methotrexate, cytarabine, ?uorouracil, mercaptopurine and azathioprine are examples.
(4) Another group of cytotoxic drugs are the vinca alkaloids such as vincristine, vinblastine and vindesima.
(5) Platinum compounds such as carboplatin, cisplatin and oxaliplatin are e?ective. All of them are given intravenously, but the latter two tend to have more unpleasant side-effects. Carboplatin and cisplatin are useful in the treatment of solid tumours. Carboplatin, a derivative of cisplatin, is given intravenously in ovarian cancer and in small-cell lung cancer. Better tolerated than cisplatin, the drug causes less nausea and vomiting, nephrotoxicity, neurotoxicity and ototoxicity. Where platinum-containing therapy has failed, intravenous treatment with paclitaxel may be tried. With only a limited success rate, it is relatively toxic and should be carefully supervised; responses, however, are sometimes prolonged.
Also of increasing importance in treating cancer are interferons. These are naturally occurring proteins with complex effects on immunity and cell function. Although toxic, with numerous adverse effects, they have shown some anti-tumour e?ect against certain lymphomas and solid tumours.... cytotoxic
A commonly occurring virus of the herpes virus group – the name derived from the swollen appearance of infected cells (‘cytomegalo’ = large cell). The infection is usually asymptomatic (or like mild in?uenza), but it can cause an illness similar to infectious MONONUCLEOSIS. Most people (80 per cent) will have had CMV infection by the time they are adults, but the virus can remain latent in the body and cause recurrent infections. During an acute infection the virus is excreted in saliva, breast milk and urine as well as from the vagina, and this may continue for years. CMV is transmitted naturally by saliva or during sexual contact, but blood transfusions and organ transplantations are also infection routes. Although CMV rarely causes its host any problems, when it is passed from an infected mother to her fetus in utero or to an infant during birth (from vaginal secretions) or via breast milk postnatally, the virus causes a generalised severe infection in the infant. This can involve the central nervous system and liver, causing death of the fetus or neonate. If the infant survives it may be mentally retarded, with motor disabilities, deafness and chronic liver disease. In England and Wales about 400 babies a year are born with CMV-induced disabilities. If an adult is immunode?cient (see IMMUNODEFICIENCY) because of HIV infection/AIDS or as a result of immunosuppressive treatment after an organ transplant, he or she may become seriously ill.... cytomegalovirus (cmv)
A substance or reaction that acts against chemical or biological damage to cell membranes. The most common cytoprotectant actions are on the skin and the liver (hepatoprotectant), although there has been recent research involving lymphocyte T-cell cytoprotectants.... cytoprotectant
The study of the microscopic appearances of cells in health and disease. (See also cytology.)... cytopathology
the *aspiration of specimens of cells from tumours or cysts through a hollow needle, using a syringe, and their subsequent examination under the microscope after suitable preparation (by staining, etc.). The technique is now used widely, especially for superficial cysts or tumours, and has become a specialized branch of diagnostic pathology. See also fine-needle aspiration cytology.... aspiration cytology
n. the study of chemical compounds and their activities in living cells.... cytochemistry
n. a compound consisting of a protein linked to *haem. Cytochromes act as electron transfer agents in biological oxidation-reduction reactions, particularly those associated with the mitochondria in cellular respiration. See electron transport chain.... cytochrome
n. a member of a family of proteins – *keratins – found in the cytoplasm of epithelial tissues and the cancers arising in them (*carcinomas). Any given carcinoma has its unique pattern of cytokeratins, which can be identified on histochemical analysis of a specimen and can help in the diagnosis of metastatic carcinoma when the primary site of metastasis is unknown.... cytokeratin
(cytokine modulator) any one of a group of agents that inhibit the activity of cytokines, especially *tumour necrosis factor alpha (TNF-?). They include *infliximab, *etanercept, and *adalimumab, known as anti-TNF drugs, which are used as *disease-modifying antirheumatic drugs and to treat inflammatory bowel disease.... cytokine inhibitor
n. division of the cytoplasm of a cell, which occurs at the end of cell division, after division of the nucleus, to form two daughter cells. Compare karyokinesis.... cytokinesis
n. the breakdown of cells, particularly by destruction of their outer membranes.... cytolysis
n. the changes undergone by a cell in the course of its life cycle.... cytomorphosis
n. a deficiency of one or more of the various types of blood cells. See eosinopenia; erythropenia; lymphopenia; neutropenia; pancytopenia; thrombocytopenia.... cytopenia
n. the study of chemical compounds in living cells by means of a cytophotometer, an instrument that measures light intensity through stained areas of cytoplasm.... cytophotometry
the inheritance of characters controlled by genes present in the cell cytoplasm rather than by genes on the chromosomes in the cell nucleus. An example of cytoplasmic inheritance is that controlled by mitochondrial genes (see mitochondrion).... cytoplasmic inheritance
n. one of the nitrogen-containing bases (see pyrimidine) that occurs in the nucleic acids DNA and RNA.... cytosine
n. the part of a cell that is outside the nucleus.... cytosome
a type of T *lymphocyte that destroys cancerous cells, virus-infected cells, and *allografts. Cytotoxic T cells recognize peptide antigens attached to proteins that are encoded by the *HLA system.... cytotoxic t cell
(FNA cytology) a technique in which a thin hollow needle is inserted into a mass to extract a tissue sample for microscopic examination. It is useful for detecting the presence of malignant cells, particularly in lumps of the breast and thyroid. See also aspiration cytology.... fine-needle aspiration cytology
a technique in which cells are tagged with a fluorescent dye and then directed single file through a laser beam. The intensity of *fluorescence induced by the laser beam is proportional to the amount of DNA in the cells.... flow cytometry
any drug that damages or destroys cells: usually refers to those drugs used to treat various types of cancer. There are various classes of cytotoxic drugs, including *alkylating agents (e.g. *chlorambucil, *cyclophosphamide, *melphalan), *antimetabolites (e.g. *fluorouracil, *methotrexate, *mercaptopurine), *anthracycline antibiotics (e.g. *doxorubicin, *daunorubicin, *dactinomycin), *vinca alkaloids, and platinum compounds (e.g. *carboplatin, *cisplatin). Other cytotoxic drugs include *taxanes and *topoisomerase inhibitors, and some *monoclonal antibodies (e.g. *bevacizumab, *trastuzumab) have cytotoxic activity. All these drugs offer successful treatment in some conditions and help reduce symptoms and prolong life in others. Cytotoxic drugs destroy cancer cells by interfering with cell division, but they also affect normal cells, particularly in bone marrow (causing *myelosuppression), hair follicles (causing hair loss), the stomach lining (resulting in severe nausea and vomiting), mouth (causing soreness), and fetal tissue (they should not be taken during the later stages of pregnancy). Dosage must therefore be carefully controlled. See also chemotherapy.... cytotoxic drug
(LBC) a technique used for analysing *cervical smears taken for *cervical screening. The specimen is collected using a brush or spatula and then mixed with a liquid preservative fluid. In the laboratory, this fluid is spun and filtered to remove blood and other extraneous material, leaving a thin layer of cells that is spread on a microscope slide and examined. LBC yields specimens that are easier to screen and give more accurate results than those obtained by the traditional Pap test.... liquid-based cytology
referring to cytophylaxis – the process of increasing the activity of leucocytes in defence of the body against infection.... cytophylactic
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