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(sun′dow-nĭng) Confusion or disorientation that increases in the afternoon or evening. It is a common finding in patients with cognitive disorders, e.g., older persons with dementia, and tends to improve when the patient is reassured and reoriented.


Eyeglasses that protect the eyes from exposure to visible as well as ultraviolet rays. For optimal eye protection outdoors, wraparound sunglasses or solar shields that block both ultraviolet A and ultraviolet B rays should be worn.

sunrise view

An x-ray of the knee in flexion, taken to highlight the patella and its relation to the femoral condyles, e.g., in evaluations of osteoarthritis. SYN: skyline view.


A substance used as a second line of defense against damage to the skin by ultraviolet rays. It is usually applied as an ointment or cream. SEE: photosensitivity; ultraviolet radiation.

image Sunscreens are much less effective in protecting against the damaging effects of the sun than avoiding midday sunlight and wearing protective clothing and headgear—these are the primary defenses against solar injury. Sunscreens should be reapplied after vigorous exercise and swimming. Some sunscreens may cause allergic or contact dermatitis.

sunscreen protective factor index

SEE: under index.


(sŭn′strōk) [AS. sunne, sun, + strake, a blow] Heatstroke.


Darkening of the skin caused by exposure to the sun. SEE: tanning salon; sunburn; sunscreen.

image A suntan predisposes exposed skin to basal cell carcinoma, squamous cell carcinoma, melanoma, and premature aging.


[L. super, over, above] Prefix meaning above, beyond, superior. SEE: hyper-.


(soo″pĕr-ăn′tĭ-jĕn) An antigen that binds with class I major histocompatibility antigens and T-cell receptors and causes the simultaneous activation of large numbers of T cells and massive release of cytokines. Such antigens do not have to be processed by macrophages to be recognized by T cells. Exotoxins from bacteria such as staphylococci and group A streptococci act as superantigens. A superantigen known as toxic shock syndrome toxin-I causes toxic shock syndrome.


(soo′pĕr-bŭg″) 1. Any pathogenic microorganism that has developed resistance to multiple drugs normally used to eradicate or control it. 2. An insect that has developed immunity to insecticides normally used to eradicate or control it.


(soo″pĕr-sen″tĕ-ner′ē-ăn) [super- + centenarian] 1. Having lived more than 110 years. 2. A person who has lived more than 110 years.


(soo″pĕr-sĭl′ē-ă-rē) [L. supercilium, eyebrow] Pert. to or in the region of an eyebrow. SYN: supraciliary...

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