Summary The Indium-labelled somatostatin analogue pentetreotide has been successfully developed for imaging of somatostatin receptor positive tumours. However there is significant renal tubular uptake of the radiolabelled peptide, which can obscure upper abdominal tumours and would preclude its use for targeted radiotherapy. The aim of this study was to determine whether amino acid infusion, which has been shown to block renal tubular peptide reabsorption, diminishes renal parenchymal uptake of this radiolabelled analogue.Eight patients being scanned with the "'In-labelled somatostatin analogue, pentetreotide, for localisation of gastroenteropancreatic tumours received an infusion of synthetic amino acids. The ratio of isotope uptake in kidney to that in spleen was assessed, and compared to the ratio for matched control patients, to determine if amino acid infusion reduced renal parenchymal uptake of the radiopharmaceutical. The amount of isotope in the urine was determined to ensure that any effect of the amino acid infusion was unrelated to changes in clearance.Infusion of amino acids significantly reduced renal parenchymal uptake of isotope at 4 h. There was a non-significant increase in urinary clearance of isotope over the 4 h, consistent with reduced reuptake and a lack of effect on glomerular filtration rate.This technique, by preventing renal damage, may allow the use of this somatostatin analogue for local radiotherapy, and could be of wider value in blocking tubular re-uptake of potentially nephrotoxic agents, such as radiolabelled Fab fragments.

1. After a 4 min period of maximal exercise in 10 normal subjects (14 studies), there was a consistent decrease in total blood volume and a consistent increase in erythrocyte indices, which were maximal immediately after exercise. Peripheral platelet and leucocyte counts increased, but did not reach maximal values until 5-10 min after the end of exercise. 2. The distributions of 99mTc-labelled erythrocytes (five studies), 111In-labelled platelets (five studies) and 111In-labelled granulocytes (four studies) were monitored with a gamma-camera immediately after injection and before and after maximal exercise performed 60 min after injection. 3. Labelled erythrocytes equilibrated rapidly between the spleen and circulating blood after injection, whereas labelled platelets and granulocytes equilibrated more slowly. After exercise, each cell type was released from the spleen with a time course that was the reciprocal of the time course of the corresponding cell count in peripheral blood. Thus, whereas the radioactivity of 99mTc-labelled erythrocytes in the spleen, which fell to 0.46 (SD 0.09) of the pre-exercise value, increased towards its baseline value as soon as exercise was completed, the radioactivities of 111In-labelled platelets and 111In-labelled granulocytes decreased, to respective minimum values of 0.61 (0.09) and 0.63 (0.09) of the pre-exercise levels, 5-10 min after the end of exercise. The exercise-induced changes in lung radioactivity for each cell type, and their time courses, broadly reflected those in the corresponding cell counts in peripheral blood. Liver radioactivity tended to decrease for each cell type.(ABSTRACT TRUNCATED AT 250 WORDS)

1. It is widely believed that the lung is an important site of granulocyte margination and releases most of the granulocytes of the peripheral neutrophilia of exercise. 2. We measured granulocyte margination in the lung in terms of the lung total blood granulocyte pool and the lung circulating granulocyte pool in eight patients without inflammatory disease or evidence of lung pathology by comparing the regional gamma-camera lung count rate of 111In-labelled granulocytes with that of 111In-labelled erythrocytes. According to the respective 111In activities in peripheral blood samples taken between 5 and 40 min after granulocyte injection, the lung marginating granulocyte pool was 0.78 (SEM 0.045) of the lung total blood granulocyte pool or 4.6 (0.92) of the lung circulating granulocyte pool 5 min after injection, decreasing to plateau values of 0.57 (0.053) and 1.53 (0.28) from 20 min after injection. This compared with corresponding whole-body ratios of about 0.6 and 1.5, respectively. 3. After 4 min of maximal exercise in four normal subjects given 111In-labelled granulocytes 60 min before exercise, the 111In-labelled granulocyte count rate over the lung increased to 1.23 (0.05) of the pre-exercise value with a time course that was essentially identical with the time course of the peripheral native neutrophilia. The spleen 111In signal decreased with the same time course, reaching a minimum of 0.63 (0.05) of the pre-exercise level at 5-10 min after the end of exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Sixteen healthy male volunteers participated in a randomized, double blind, parallel groups study. Subjects received either 1 or 5 mg SDZ CO 611 (a new, orally active somatostatin analog) twice daily over a 14-day period and acted as their own controls. Gastric emptying of 99mTc and mouth to cecum transit time, as measured by the breath hydrogen technique, after a mixed meal containing lactulose and 99mTc-diethylenetriaminepentaacetate, were assessed once before, twice during, and once after the period of study medication. Gastric emptying of 99mTc was significantly accelerated by the higher dose of SDZ CO 611, whereas mouth to cecum transit time was prolonged by the drug in a dose-dependent manner. Both doses of SDZ CO 611 led to suppression of the fasting level and postprandial release of several gastrointestinal and pancreatic hormones. This effect was more marked in those subjects taking 10 mg/day of the study medication. Motilin and pancreatic polypeptide were the most sensitive to the inhibitory actions of the analog. Glucose tolerance was significantly impaired by the 10-mg dose of the drug. We conclude that this new, orally active derivative of somatostatin is as effective on the gastrointestinal tract as the sc somatostatin analog octreotide. It would, therefore, be a useful advance in the treatment of gastroenteropancreatic tumors.

A 99Tcm aerosol of particle size 0.12 micron and the gas 81Krm were administered to four normal subjects and to eleven patients with airway disease. Posterior-anterior gamma camera images of erect lungs were compared qualitatively and quantitatively, and 99Tcm clearance rates were measured. Qualitatively the two images were similar in normal subjects but differed in most patients owing to small regions of high count density in the 99Tcm images. In a few patients, regional variations in ventilation were defined more finely by the aerosol. In both groups a significant vertical gradient in 99Tcm count density relative to 81Krm count density was found. Penetration of 99Tcm to the lung periphery relative to the hilar region was similar to that of 81Krm in the normal subjects and less than that of 81Krm in the patients. Possible causes of the differing distributions are discussed. The images obtained with the aerosol in the two groups studied were similar to those reported for larger particle aerosols.