Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «S»:
Silencing, gene: A mechanism by which cells shut down large sections of chromosomal DNA. Gene silencing is done by incorporating the DNA to be silenced into a form of DNA called heterochromatin that is already silent.
The process of gene silencing is important for the differentiation of many differ...
Silent stroke: Small strokes that do not cause any symptoms. Silent strokes still damage brain tissue. The most common symptom of a stroke is weakness or paralysis on one side of the body or the other. There may be a partial or complete loss of voluntary movement and/or sensation in a leg and/or ar...
Silica: The chief component of sand and a substance responsible for lung disease and cancer.
Crystalline silica of respirable size is primarily quartz dust occurring in industrial and occupational settings in the form of fine, breathable particles. Respirable crystalline silica results from mining a...
Silicatosis: See: Silicosis....
Silicosis: A form of lung disease resulting from occupational exposure to silica dust over a period of years. Silicosis causes slowly progressive fibrosis of the lungs, impairment of lung function and a tendency to tuberculosis of the lungs.
Crystalline silica of respirable size is primarily quartz ...
Silk Road disease
Silk Road disease: Behcet's disease. Called Silk Road disease because it is most common and more severe in people originating from countries along the Silk Road, the vast network of ancient trade routes connecting China with the Mediterranean Basin....
Silver: A metal used in some medications and in
many "natural" remedies, as well as in silver amalgam for
filling cavities in teeth. Silver has antibiotic
properties. However, overuse of silver, or use of products
containing silver by people with certain health conditions,
can result in silver...
Silver bullet: Or magic bullet.
1. The perfect drug to cure a disease with no danger of side effects. The term magic bullet was first used in this sense by the German scientist Paul Ehrlich to describe antibody and, later, the drug salvarsan that he created to treat syphilis.
2. In general, a mag...
Silver poisoning : Silver poisoning, medically termed argyria, causes ashen gray discoloration of the skin (and other tissues of the body). Due to chronic use of silver salts.
For example, a medical report related the case of a woman, now in her 50s, with discolored skin. At 11 she had been given no...
Simian crease: A single transverse palmar crease, a minor variation associated with Down syndrome (trisomy 21). Also called a four-finger crease, single palmar flexion crease, single upper palm crease, or line.
There are most often two transverse palmar creases, a proximal one and a more distal one...
Simian virus 40
Simian virus 40: See: SV40....
Single base change
Single base change: A change in which a single base in the DNA differs from the usual base at that position. These single base changes are also called SNPs or "snips."
Millions of SNP's have been cataloged in the human genome. Some SNPs such that which causes sickle cell are responsible for disease...
Single gene disease
Single gene disease: Any genetic disorder caused by a change affecting only one gene.
There are thousands of single-gene diseases including achondroplasia,
cystic fibrosis, hemophilia,
muscular dystrophy, and
sickle cell disease .
Single-gene diseases usually follow simple M...
Single nucleotide polymorphism
Single nucleotide polymorphism: A change in which a single base in the DNA differs from the usual base at that position. Abbreviated SNP and pronounced snip.
Millions of SNP's have been cataloged in the human genome. Some SNPs are responsible for disease such as the SNP responsible for sickle cell ...
Single palmar flexion crease
Single palmar flexion crease: See: Simian crease.
Single upper palm crease
Single transverse palmar line
Single palmar flexion line
Single upper palm line...