| tumor | 1. <oncology> An abnormal mass of tissue that results from excessive cell division that is uncontrolled and progressive, also called a neoplasm. Tumours perform no useful body function. They may be either benign (not cancerous) or malignant. 2. Swelling, one of the cardinal signs of inflammations, morbid enlargement. Origin: L. Tumere = to swell (12 May 1997) |
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| tumor marker | <investigation, oncology> A substance in the body that usually indicates the presence of cancer. These markers are usually specific to certain types of cancer and are usually found in the blood or other tissue samples. Examples are alphafetoprotein (AFP), human chorionic gonadotropin, and lactate dehydrogenase (LDH). They may be indicators of tumour stage and grade as well as useful for monitoring responses to treatment and predicting recurrence. Many chemical groups are represented including hormones, antigens, amino and nucleic acids, enzymes, polyamines, and specific cell membrane proteins and lipids. (18 Jul 2002) |
| tumor necrosis factor | <cytokine> Originally described as a tumour inhibiting factor in the blood of animals exposed to bacterial lipopolysaccharide or Bacille Calmette-Guerin. Preferentially kills tumour cells in vivo and in vitro, causes necrosis of certain transplanted tumours in mice and inhibits experimental metastases. Human Tumour Necrosis factor alpha is a protein of 157 amino acids and has a wide range of pro inflammatory actions. Usually considered a cytokine. Synonym: cachectin. Acronym: TNF (13 Nov 1997) |
| heterologous | <molecular biology> Derived from the tissues or DNA of a different species. Compare: autologous, homologous. (18 Nov 1997) |
| heterologous antiserum | An antiserum that reacts with (e.g., agglutinates) certain microorganisms or other complexes of antigens, even though the antiserum was produced by means of stimulation with a different microorganism or antigenic material. See: homologous antiserum. (05 Mar 2000) |
| heterologous desensitization | Stimulation by one agonist which leads to a broad pattern of unresponsiveness to further stimulation by a variety of other agonists. (05 Mar 2000) |
| heterologous graft | <surgery> A surgical graft of tissue from one species onto or into individuals of unlike species, genus or family. Also know as a heteroplastic graft. See: xenotransplantation. (11 May 1997) |
| heterologous insemination | Artificial insemination with semen from a donor who is not the woman's husband. Synonym: donor insemination. Homologous insemination, artificial insemination with the husband's semen. (05 Mar 2000) |
| heterologous protein | A protein that differs from any protein normally found in the organism in question. Synonym: heterologous protein. (05 Mar 2000) |
| heterologous serotype | An antibody that was induced by one antigen and reacts with another antigen. (05 Mar 2000) |
| heterologous stimulus | A stimulus that acts upon any part of the sensory apparatus or nerve tract. (05 Mar 2000) |
| heterologous tumour | A tumour composed of a tissue unlike that from which it springs. (05 Mar 2000) |
| heterologous twins | Dizygotic twins are siblings who have shared a common uterine environment. They are due to fertilization of two different ova by different sperm. Dizygotic twins are also called fraternal twins. (12 Dec 1998) |
| insemination, artificial, heterologous | Human artificial insemination in which the semen used is that of a man other than the woman's husband. (12 Dec 1998) |
| transplantation, heterologous | Transplantation between animals of different species. (12 Dec 1998) |