Portal circulation in monkeys and humans studied after ingestion of a capsule containing a radionuclide

Capsules (8 x 30 mm) of technetium-99m pertechnetate were designed for measurement of portal blood flow. Most of the radionuclide entered the superior mesenteric vein. The capsule was taken orally and monitored with a collimator for scintigraphy until it reached the small intestine, when a magnetic field completed an electrical circuit in a sensor, burning a thread, releasing a spring, and discharging the preparation. A study in crab-eating monkeys (Macaca fascicularis) showed that the radionuclide in the small intestine circulated through the superior mesenteric vein to the portal vein and liver. Portal scintigraphy through the small intestine could be analysed in the same way as per-rectal portal scintigraphy, in which blood flow mostly from the inferior mesenteric vein is evaluated. A study of four volunteers showed that, after the radionuclide was released, it circulated through the superior mesenteric vein to the portal vein and liver. Use of a capsule enclosing a radioisotope was possible, and the procedure seemed to be safe. The use of the per-small intestine method plus the per-rectal method should give more accurate results than either method used alone, because the haemodynamics of both the superior and inferior mesenteric vein would be reflected.     

Preliminary Phase I Study of Human Leukocyte Interferon: Side Effects of the Interferon

Human leukocyte interferon was administered systematically to13 Japanese patients and its side effects were evaluated. Systemicadministration of interferon caused a temporary febrile responsein most of the patients. Intravenous injection caused a moresevere but shorter response than intramuscular injection. Thelong-term administration of interferon caused an increase inneutrophils for one or a few months in six patients. No otherside effects were found in any of the patients. Because theside effects may be due to the impurity of the interferon preparations,more highly purified interferon should be used from now on.     

Studies on Erythropoietic Action of Angiotensin II

The effects of synthetic Angiotensin II on erythropoiesis were investigated.

1. Two daily intravenous injections of Angiotensin II, 100 µg./Kg. of bodyweight, revealed no acceleration of Fe⁵⁹ incorporation into erythrocytes ofeither normal rabbits or hypophysectomized rats.

2. When given by intravenous drip, 100 µg./Kg. of Angiotensin II significantly accelerated the radioiron incorporation.

3. The renal blood flow was markedly reduced throughout the period ofthe dropwise injection; the same effect was transitory after single intravenousinjection. The elevation of plasma erythropoietin activity was observed inhypertransfused polycythemic rabbits following the dropwise injection ofAngiotensin II.

From these results, it is concluded that erythropoietic activity of AngiotensinII results from an increased erythropoietin production. The increased production may have been induced by a renal ischemia through administration ofAngiotensin II.

Submitted on February 23, 1966 Accepted on January 13, 1967