Medical Conditions Terminology in Category X

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Xenogeneic Antibodies

Antibodies elicited in a different species from which the antigen originated. These antibodies are directed against a wide variety of interspecies-specific antigens, the best known of which are Forssman, Hanganutziu-Deicher (H-D), and Paul-Bunnell (P-B). Incidence of antibodies to these antigens–i.e., the phenomenon of heterophile antibody response–is useful in the serodiagnosis, pathogenesis, and prognosis of infection and latent infectious states as well as in cancer classification.

Xenogeneic Antigens

Antigens stimulating the formation of, or combining with heterophile antibodies. They are cross-reacting antigens found in phylogenetically unrelated species.

Xenogenic Antibodies

Antibodies elicited in a different species from which the antigen originated. These antibodies are directed against a wide variety of interspecies-specific antigens, the best known of which are Forssman, Hanganutziu-Deicher (H-D), and Paul-Bunnell (P-B). Incidence of antibodies to these antigens–i.e., the phenomenon of heterophile antibody response–is useful in the serodiagnosis, pathogenesis, and prognosis of infection and latent infectious states as well as in cancer classification.

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Xenogenic Antigens

Antigens stimulating the formation of, or combining with heterophile antibodies. They are cross-reacting antigens found in phylogenetically unrelated species.

Xenograft Antitumor Assay

In vivo methods of screening investigative anticancer drugs, biologic response modifiers or radiotherapies. Human tumor tissue or cells are transplanted into mice or rats followed by tumor treatment regimens. A variety of outcomes are monitored to assess antitumor effectivness.

Xenograft Antitumor Assays

In vivo methods of screening investigative anticancer drugs, biologic response modifiers or radiotherapies. Human tumor tissue or cells are transplanted into mice or rats followed by tumor treatment regimens. A variety of outcomes are monitored to assess antitumor effectivness.

Xenograft Model Antitumor Assays

In vivo methods of screening investigative anticancer drugs, biologic response modifiers or radiotherapies. Human tumor tissue or cells are transplanted into mice or rats followed by tumor treatment regimens. A variety of outcomes are monitored to assess antitumor effectivness.

X-Linked Bulbo-Spinal Atrophy

A group of disorders marked by progressive degeneration of motor neurons in the spinal cord resulting in weakness and muscular atrophy, usually without evidence of injury to the corticospinal tracts. Diseases in this category include Werdnig-Hoffmann disease and later onset SPINAL MUSCULAR ATROPHIES OF CHILDHOOD, most of which are hereditary. (Adams et al., Principles of Neurology, 6th ed, p1089)

Xanthine Alkaloids

Alkaloids, which contain xanthine as their nitrogenous base.

X-linked Adrenoleukodystrophy

An X-linked recessive leukodystrophy characterized by an abnormal accumulation of saturated very long chain fatty acids in LYSOSOMES. It primarily affects the white matter of the CENTRAL NERVOUS SYSTEM and the ADRENAL CORTEX. This disorder results from defective beta-oxidation and occurs almost exclusively in males and has multiple phenotypes. Relatively common clinical features include the childhood onset of ATAXIA; NEUROBEHAVIORAL MANIFESTATIONS; HYPERPIGMENTATION; adrenal insufficiency; SEIZURES; MUSCLE SPASTICITY; and DEMENTIA. A related condition, adrenomyeloneuropathy, usually has its onset in adult life and is characterized by spastic paraparesis, adrenal insufficiency, neuropathy, and HYPOGONADISM. (From Neuropediatrics 1998 Feb;29(1):3-13; Menkes, Textbook of Child Neurology, 5th ed, p188) The defective gene for this disorder has been localized to the long arm of the X chromosome (Xq28).