Category: Ua-Ur

The presence of excessive amounts of urea in the blood, which may be a sign of kidney disease or failure. It is also referred to as azotemia.

The urea breath test (UBT) is a procedure for diagnosing the presence of a bacterium, Helicobacter pylori (H. pylori) that causes inflammation, ulcers, and atrophy of the stomach. The test also may be used to demonstrate that H. pylori has been eliminated by treatment with antibiotics. The urea breath test is based on the ability of H. pylori to break down urea, a…

A nitrogen-containing substance normally cleared from the blood by the kidney into the urine. Diseases that compromise the function of the kidney often lead to increased blood levels of urea, as measured by the blood urea nitrogen (BUN) test. Urea is of major historical significance. It was the first organic chemical compound ever synthesized. The German chemist Friedrich…

A salt derived from uric acid. When the body cannot metabolize uric acid properly, urates can build up in body tissues or crystallize within the joints.

An increase in the number of receptors on the surface of target cells, making the cells more sensitive to a hormone or another agent. For example, there is an increase in uterine oxytocin receptors in the third trimester of pregnancy, promoting the contraction of the smooth muscle of the uterus.

An infection of the upper part of the respiratory system which is above the lungs. An upper respiratory infection can be due to any number of viral or bacterial infections. These infections may affect the throat (pharyngitis), nasopharynx (nasopharyngitis), sinuses (sinusitis), larynx (laryngitis), trachea (tracheitis) or bronchi (bronchitis). Upper respiratory infection is commonly abbreviated URI.

A neuron that starts in the motor cortex of the brain and terminates within the medulla (another part of the brain) or within the spinal cord. Damage to upper motor neurons can result in spasticity and exaggerated reflexes. There is no standard laboratory test for upper motor neuron disease.

More properly called the thigh, the upper leg is the area between the knee and the hip. It has only one bone, the femur, which spans the distance from the hip to the knee.

Not well or not in good health. Ailing, sick, or indisposed. For example, “I am well-nigh choked with the sulfurous heat of the weather — or I am unwell.” (1826, Journal of Sir Walter Scott)

Loss of one’s equilibrium in regard to the environment, often with a feeling of almost falling, or the result of bumping into things. There are many causes for unsteadiness, including problems in the cerebral or cerebellar portions of the brain, the spinal cord, vestibular system, or inner ear. Unsteadiness is medically distinct from dizziness, lightheadedness, and vertigo.