Discovery and development of direct thrombin inhibitors the binding site for the globular amino-terminal domain and exosite 1 is the binding site for the acidic carboxy-terminal domain of hirudin. Native hirudin, a 65-amino-acid polypeptide, is produced in the parapharyngeal glands of medicinal leeches. Hirudins today are produced by recombinant biotechnology using yeast. These recombinant hirudins lack a sulfate group at Tyr-63 and are therefore called desulfatohirudins. They have a 10-fold lower binding affinity to thrombin compared to native hirudin, but remain a highly specific inhibitor of thrombin and have an inhibition constant for thrombin in the picomolar range. Renal clearance and degradation account for the most part
Ciaccio's glands Ciaccio's glands Ciaccio's glands or Wolfring's glands are small tubular accessory lacrimal glands ("glandulae lacrimales accessoriae") found in the lacrimal caruncle of the eyelid. They are located in the upper border of the tarsus, approximately in the middle between the extremities of the tarsal glands. Sometimes they are situated slightly above the tarsus. There are usually 2 to 5 of these glands in the upper eyelid, and their function is to produce tears which are secreted onto the surface of the conjunctiva. They are named after Italian anatomist Giuseppe Vincenzo Ciaccio (1824–1901), who described these glands in 1874. They are