A preliminary study of brain gliomas with H17E2 monoclonal antibody: immunoscintigraphy and pharmacokinetics.

Ten patients with relapsing high grade brain gliomas and one patient with low grade glioma were studied with a monoclonal antibody (H17E2) against placental alkaline phosphatase. In addition 2 patients with relapsing high grade glioma were studied with a non specific antibody (4D513/2118). 1 mCi of Iodine-131-labelled H17E2 was administered intracarotidly (i.c.) in two, and intravenously (i.v.) in 9 patients. Immunoscintigrams were taken at 0, 2, 24, 48 and 72 hours. Radioactivity was monitored in blood and urine. Tumour/non-tumour ratios were estimated (max. 2.45). All high grade gliomas receiving specific antibody irrespective of the route of administration, gave a positive immunoscintigraphic pattern, increasing in intensity with time. Disappearance of radioactivity in blood was biexpontential with a long component over 30 hours. Urinary excretion of radioactivity ranged from 3.7-21.7% of administered dose/day. The patient with low grade glioma and the patients receiving non specific monoclonal antibody showed a negative pattern, a fast blood clearance and a high urinary excretion. We conclude that a) Iodine-131 labelled H17E2 proved to be stable in vivo and produced satisfactory tumour localisation and b) i.v. route was as good as i.c.

Dynamic evaluation of long term patency of choledochoduodenostomy compared with sphincteroplasty.

In 44 patients who had been operated upon for benign obstruction of the biliary tract and had undergone sphincteroplasty or choledochoduodenostomy seven to 12 years previously, patency of the new stoma was evaluated. Dynamic studies of bile flow were done by radioisotopic cholangiography, using 99mTc-pyridoxal-phenylalanine as an hepatobiliary imaging agent. Both surgical procedures seem to give equal results in the long term follow-up study regarding the patency of a new stoma. In view of the fact that choledochoduodenostomy involves less morbidity and mortality postoperatively, than does sphincteroplasty, the former is preferred unless a stone is impacted into the ampulla of Vater or if the common bile duct is less than 2 centimeters in diameter in instances of stricture.

Comparative in vivo kinetics of some new 99mTc-labelled acetanilido iminodiacetates.

The in vivo kinetics of five new 99mTc-labelled acetanilido iminodiacetates, analogous to 99mTc-p-butyl IDA, were studied in experimental animals by means of their distribution in mice and scintigrams of rabbits. The new compounds were specifically eliminated via the hepatobiliary system with various rates of hepatic extraction. Urinary excretion of the complexes was minimal.

Absorbed dose estimation of some 99mTc-hepatobiliary agents.

The absorbed dose estimates of several organs after administration in humans of six new hepatobiliary agents (five 99mTc-Pyridoxal amino acid complexes and the 99mTc-HIDA) are presented in comparison with 131I-Rose-Bengal. The results indicated that the radiation doses absorbed by the total body and gonads as well as by the critical organ (upper part of the large intestine) are significantly lower than those of Rose Bengal. Therefore, the new 99mTc-agents can be safely applied to humans.

99MTc-HIDA, a gallbladder imaging agent: experimental aspects.

The molecule N-(2,6-dimethyl-phenyl-carbamoyl-methyl)-iminodiacetic acid (HIDA), capable of chelating reduced 99mTc, was synthesized, characterized, labeled with 99mTc, and studied in experimental animals. The results indicated that the new 99mTc-radiopharmaceutical is rapidly cleared from the blood to the liver, then rapidly removed to the gallbladder and excreted into the duodenum through the common bile duct. A comparative kinetic study of 99mTc-HIDA and 131I-Rose Bengal performed in rabbits demonstrated that both radiopharmaceuticals had a similar blood clearance rate, but cleared at a different rate from liver to gallbladder. 99mTc-HIDA showed a faster accumulation in the gallbladder than 131I-Rose Bengal. These findings, combined with the advantage of the low acute toxicity of HIDA, were promising enough to encourage a further evaluation and clinical investigation of this new Tc-99m hepatobiliary agent.

Evaluation of Tc-99m pyridoxal-phenylalanine as a hepatobiliary imaging agent. Part 1. Experimental studies.

In this experimental study, the usefulness of a new radiotracer, Tc-99m pyridoxal-phenylalanine ("Tc-PPh"), is evaluated as a hepatobiliary imaging agent, and results are compared with those of conventional cholangiography. In the presence of a normal biliary tree or in cholelithiasis, information derived from conventional cholangiography is of better quality. The radiotracer technique, however, is very useful for the demonstration of cholopeptic bypass procedures, even in the presence of jaundice, and also in cases of intraperitoneal bile leakage.

Evaluation of Tc-99m pyridoxal-phenylalanine as a hepatobiliary agent. Part 2. Clinical tests.

Twenty-four patients with normal or diseased hepatobiliary systems were subjected to a clinical trial in order to evaluate Tc-99m pyridoxal-phenylalanine as a biliary imaging agent. The investigation was combined with i.v. cholecysto-cholangiography in most cases, and the results were compared. It is concluded that qualitative information derived from conventional i.v. cholangiography is better in demonstrating the normal biliary tree or gallstones. The radiotracer techniques, however, are valuable in dynamic studies of Oddi's sphincter, in showing patency of biliary by-pass procedures, and in differentiating hepatocellular from obstructive jaundice.

Haemophlic arthropathy surveyed with whole-body gamma-camera scinitgraphy.

A number of joints suffering from haemophilic arthropathy was studied. They were surveyed clinically, radiologically, and with a new system of whole-body gamma-camera scintigraphy. This radio-isotopic technique provides advantages such as sensitivity, speed and safety. The results of the survey are presented and discussed.