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1. unit. 2. Symbol for the element uranium. 3. Unknown.


Isotope of uranium with atomic weight 235.


one hundred units of insulin per mL of solution. A common concentration of commercially available insulins. Similarly, U-500 signifies that 500 units of insulin are present in 1 mL of solution.


Unstable angina.


urine albumin-to-creatinine ratio.


upper airway obstruction.


(ū-bik′wĭ-nol″) [ubiquit(ous) + -ol] Coenzyme QH2, the reduced form of ubiquinone.


(ū-bik′wĭ-nōn″, ū″bi-kwi-nōn′) [ubi(quitous) + quinone] A lipid-soluble quinone present in virtually all cells. It is a vitamin-like substance that can be synthesized from tyrosine in a multistep process, collects reducing equivalents during intracellular respiration, is a coenzyme for several mitochondrial enzymes involved in production of adenosine triphosphate, and is converted to its reduced form, ubiquinol, while involved in this process. Ubiquinone is widely used in Europe and Asia as a health food supplement for congestive heart failure and other disorders, although confirmation of its effectiveness is uncertain. SYN: coenzyme Q10.


(ū-bik′wĭt-ĭn) [ubiquit(ous) + -in] An intracellular protein that helps to destroy misfolded proteins. It is also important in promoting the functions of proteins that make up ribosomes.


(ū-bik′wĭt-ŭs) [L. ubique, everywhere] 1. Wildly spread in the environment, esp. at the same time; broadly distributed. 2. Systemic. 3. Pancellular.


urea breath test.


Usual body weight.


Urea cycle disorder.


undifferentiated connective tissue disease.


uridine diphosphate.


Unscheduled DNA synthesis.

Uhthoff sign

(oot′hof″) [Wilhelm Uhthoff, Ger. ophthalmologist, 1853–1927] In patients with multiple sclerosis, a transient worsening of neurological deficits when body temperature rises, e.g., a decrease in vision, double vision, or nystagmus.


Urinary incontinence.


(ŭl′sĕr, ŭl′sĕr-ă) pl. ulcera [L. ulcus, stem ulcer-, sore, ulcer] An open sore that forms on an epithelial surface, e.g., the skin, the mucous membranes, or the lining of the gastrointestinal tract, marked by inflammation, necrosis, and sloughing of damaged tissues. A wide variety of insults may produce ulcers, including trauma, caustic chemicals, intense heat or cold, arterial or venous stasis, cancers, ...

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