Tetragnost

TETRAGNOST, tetrahalogenated substituted phenolphthaleins, used in X-ray diagnosis of the biliary tract (see Gallbladder, X-ray diagnosis) and for functional diagnosis of the liver, due to the property of these compounds of being excreted almost exclusively with bile. There are three types of T. The most important is: I. Iodotetragnost, tetraiodophenolphthalein sodium. A blue-gray crystalline powder, turning blue on exposure to air, odorless, easily soluble in water. It is sterilized by boiling. When excreted by the bile, iodotetragnost, accumulating in the gallbladder, provides sufficient contrast for X-ray examination (cholecystography). Since the excretion of T. depends on the functional capacity of the liver, the natural prerequisite for the use of iodotetragnost is the absence of severe damage to the liver parenchyma. It is used: a) intravenously at a dosage, according to Whitaker, of 35 mg per 1 kg of body weight; 2.5-3.5 g are dissolved in 30-40 cm³ of distilled water, filtered through paper filter, heated for 15-20 minutes in a water bath, and after cooling, slowly injected (over 4-5 minutes) into a vein. It is recommended to inject several cm³ of physiological solution through the same needle before and after administration to avoid damage to the vessel wall. To prevent general reactions, patients should lie on their back for half an hour. After 8 hours, sometimes already after 4 hours, it is usually possible to obtain on the X-ray film a sufficiently clear shadow of the bladder, on which stones appear either as darker (calcium) or lighter (cholesterol) spots. The absence of a bladder shadow even after 12 hours indicates obstruction of the cystic duct or a sclerosing inflammatory process in the bladder. For a more rapid appearance of contrast, Antonucci proposes simultaneously with iodotetragnost injecting into a vein 50 g of glucose in a 40% solution; with this method, the bladder becomes visible after half an hour, reaching maximum visibility after 2 hours. b) Orally in the form of oral-tetragnost is used iodognost (oral-tetragnost), 25 cm³ of a 6% aqueous solution together with a light meal. X-ray examination is performed after 13, 15, sometimes 18 and 20 hours. Previously, for internal use, T. was used in glutoid capsules containing 0.5 g of iodotetragnost, the disadvantage of which was their uneven dissolution. Internal administration of iodotetragnost is preferred by many authors, as it avoids the phlebitis occasionally encountered with intravenous administration. II. Bromotetragnost, proposed in 1925 by Graham and Cole for cholecystography, was quickly replaced by iodotetragnost, as it requires smaller doses and produces fewer side effects. It was used in capsules of 0.5 g (10-12 capsules). III. Chlorotetragnost, phenoltetrachlorophthalein sodium (unlike iodotetragnost and bromotetragnost, where the halogen is attached to the phenyl radical, here chlorine is attached to the phthalic acid residue). Proposed by Rosenthal for functional diagnosis of the liver. 5 mg of chlorotetragnost per 1 kg of body weight is injected intravenously in 25.0 of physiological solution; after an hour, blood is taken from a vein with another syringe and centrifuged; the serum is acidified with 2-3 drops of 2% HCl and 5% NaOH is layered on top. In the presence of chlorotetragnost, a bluish or bright red ring appears at the boundary. The same determination is performed in urine. A positive reaction indicates liver damage. A significantly more accurate modification is Bogen's: the blood serum, taken one hour after administration of chlorotetragnost, is distributed into 2 test tubes, to one is added 2 drops of 10% NaOH; the intensity of the red color appearing is compared with standard solutions of chlorotetragnost with alkali, placed before the second test tube with serum. A chlorotetragnost content of up to 0.3 mg% indicates normal function, up to 1 mg% indicates mild disorders, and above that indicates severe disorders of the excretory function of the liver. Iodognost is manufactured at the Semashko factory.