De Quervain's tenosynovitis is inflammation of tendons on the side of the wrist at the base of the thumb. These tendons include the extensor pollicis brevis and the abductor pollicis longus tendons, which extend the joints of the thumb. De Quervain's tenosynovitis can be brought on by simple strain injury to the extensor pollicis longus and abductor pollicis tendons. Typical causes include stresses such as lifting young children into car seats, lifting heavy grocery bags by the loops, and lifting gardening pots up and into place.
double helix. n. The coiled structure of double-stranded DNA in which strands linked by hydrogen bonds form a spiral configuration, with the two strands oriented in opposite directions.
DNA Structure and Function. 1  Watson-Crick model of DNA; double helix. 2  The double in the double helix means that DNA is found in a double-stranded form - 2 single-stranded chains of DNA stuck to each other via hydrogen bonding of the base pairs.3  The 2 single-strands are anti-parallel to each other. The double in the double helix means that DNA is found in a double-stranded form - 2 single-stranded chains of DNA stuck to each other via hydrogen bonding of the base pairs. 2  The 2 single-strands are anti-parallel to each other. 3  Going from 5' to 3' of one strand means going from 3' to 5' of the other strand.