الوصف
Porphyrins are intermediary metabolites in the synthesis cycle of haem. Several enzymes are involved in the process of converting haem into aminolevulinic acid (ALA), porphobilinogen,hydroxymethylbilane, uroporphyrinogen I, uroporphyrinogen III, protoporphyrinogen, protoporphyrin and back into haem. Control of the rate of haem synthesis is achieved largely by a negative-feedback effect by haem on the enzyme ALA synthase. Porphobilinogen deaminase is also involved to some extent in the control of haem synthesis. Increased ALA synthase activity is responsible for the excess production of intermediary metabolites (porphyrins) in most porphyrias, which are toxic to the nervous system. Porphyrias are classified according to the source (liver or erythroid tissue) of excess porphyrins or whether the affected patient suffers acute attacks, dermatological manifestations or both.
دواعي الإستعمال
Increased porphyrin levels are associated with Nonacute Porphyrias (Porphyrias producing cutaneous lesions) which include Congenital Erythropoietic Porphyria, Porphyria Cutanea Tarda, Toxic Porphyria, Hepato-Erythropoietic Porphyria, Harderoporphyria and Protoporphyria, and Acute Porphyrias (Porphyrias producing neurological symptoms) which include Acute Intermittent Porphyria, and ALA dehydratase deficiency. Porphyrins are also increased in Porphyrias producing both neurological and cutaneous manifestations such as Variegate Porphyria and Hereditary Coproporphyria.
نوع العينة والكمية والشروط
30 ml of 24 Hrs Urine Protect From Light
إحتياطات خاصة
State 24 Hrs urine volume. Avoid additives. Keep refrigerated during collection.
المعدل الطبيعي
By Report
