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
Ectopic salivary gland tissue the salivary glands, including cancer, may also occur within an accessory salivary gland tissue. "Salivary gland heterotopia" is where salivary gland acini cells are present in an abnormal location without any duct system. The most common location is the cervical lymph nodes. Other reported sites of heterotopic salivary gland tissue are the middle ear, parathyroid glands, thyroid gland, pituitary gland, cerebellar pontine angle, soft tissue medial to sternocleidomastoid, stomach, rectum and vulva. Salivary gland neoplasm occurrence within heterotopic salivary gland tissue is rare. Ectopic salivary gland tissue Ectopic salivary gland tissue which is located in sites other than the normal