Online Medical Dictionary
- X Chromosome
- One of the two sex determining chromosomes composing humans. Male characteristics will usually be incited by the chromosomal pairing of XY while female characteristics by the pair XX.
- A gene carried on the X chromosome that will indicate a particular trait. Genes are more commonly carried on the X chromosome, thus the prevalence of X-linked conditions over those Y-linked. As men have only one X chromosome in a pair, they will be more likely to inherit an X-linked dominant trait.
- The electromagnetic rays composing X-radiation, shorter in length than UV rays but longer than gamma rays. X-ray technology is used in medical imaging techniques used to identify bone structures and detect various pathologies in soft tissues. In addition to basic X-ray, X-ray technology is used in fluroscopy, computer tomography (or CT scans), and radiotherapy. Increased exposure to the ionizing radiation emitted by X-ray contributes to the risk of cancer and other developmental conditions.
- Nodules, or boil-like bumps, appearing on the skin, composed of cholesterol-rich lipid deposits. Xanthoma, or xanthomata, is associated with chronic biliary obstruction and the hyperlipidemias, conditions wherein an abnormal level of lipids are present in the blood, which may occur as a result of a genetic condition or an underlying disease such as diabetes.
- A yellowing of the skin caused by an accumulation of cholesterol in the cells of the skin. A yellowing, or xanthosis, of degenerating tissue may be induced by an underlying malignancy.
- A prefix meaning from another, or foreign.
- Substances present in one organism naturally and able to enter another organism where that substance is not created naturally, such as in an antibiotic, or hormones secreted by one organism into water or air and taken in by another.
- Tissues, cells or organ taken from one species to be transplanted in another, such as in the tissue of a baboon to be transplanted to replace the decaying or diseased tissue of a human. Also termed xenotransplants.
- The surgical procedure to remove cells, organ or tissues from one species into another. Xenotransplantation between animal and human is being increasingly argued and explored an alternative to long organ recipient wait lists.