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(nĕf″rō-tō-mŏg′ră-fē) [″ + ″ + graphein, to write] Tomograph of the kidney after the intravenous injection of a radiopaque contrast medium that is excreted by the kidney.


(nĕ-frŏt′ō-mē) [″ + tome, incision] Surgical incision of the kidney.


(nef″rŏ-tok′sĭn) [nephro- + toxin] A substance that is toxic to and damages kidney tissues. Common nephrotoxins include aminoglycoside antibiotics (such as amikacin, gentamicin, or tobramycin), glycopeptide antibiotics (vancomycin), nonsteroidal anti-inflammatory drugs (such as indomethacin), lead (as in moonshine [whiskey] and some paints), and some ionic radiocontrast agents. nephrotoxic (nef″rŏ-tok′sĭk), adj.


An enzyme that is attached to the outer surface of many cell membranes and degrades peptide neurotransmitters. Concentrations of neprilysin, which decrease as people age, also degrade amyloid beta peptide whose abnormal misfolding and aggregation in neural tissue has been implicated as a cause of Alzheimer disease. SEE: amyloid beta peptide.


(nep-too′nē-ŭm, -tu′) [Neptune (the planet) + -ium] SYMB: Np. A radioactive chemical element obtained by bombarding uranium with neutrons, atomic weight (mass) 237, atomic number 93.


(nĕrv) [L. nervus, sinew] Parallel axons running together inside an epineurium (thick connective tissue sheath). In the nerve, axons are wrapped into small bundles by endoneuria (thin connective tissue sheaths); each small bundle of axons is called a fascicle. The neuronal cell bodies of a nerve's axons are in the brain, the spinal cord, or ganglia, but the nerves run only in the peripheral nervous system. Nerves with axons that conduct electrochemical impulses toward the central nervous system (CNS) are afferent, nerves with axons that conduct impulses away from the CNS are efferent, and nerves with both afferent and efferent axons are mixed. Nerves in the peripheral nervous system are roughly analogous to tracts in the CNS and, like tracts, act as highways that axons can join or leave on the way from their origin to their target. SEE: ansa; cell; nervus; illus.





SYMPTOMS: A broad array of insults may damage nerves, including direct trauma, repetitive motion injuries, compression by neighboring structures, glycosylation, infections, drugs, toxins, and paraneoplastic syndromes. Symptoms of nerve injury include paresthesias, loss of sensation and position sense, impaired motor function, cranial nerve malfunction, changes in reflexes, and impairments in glandular secretion.

TESTS FOR LOSS OF FUNCTION: The assessment of nerve injury includes a careful neurological examination, sometimes accompanied by tests, e.g., electromyography or nerve conduction studies.

abducens n. A somatic motor nerve originating in the abducens nucleus in the pons. It runs in the subarachnoid space and the cavernous sinus inside ...

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