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.

Symptoms and signs suggestive of myotonia have been described in association with hypothyroidism. Since these are relieved by treatment of the thyroid condition, they have been regarded as part of the hypothyroid state (Hoffmann, 1896; Debrd and Semelaigne, 1935).This paper records a case in which myotonia congenita (Thomsen's disease) and hypothyroidism were present simultaneously and in which the myotonia was not completely relieved even when the patient was made hyperthyroid.Myotonia congenita is a hereditary disease of muscle characterized by prolonged involuntary contraction following a voluntary contraction (active myotonia) or mechanical stimulation (mechanical myotonia). The condition was first described by Leyden (1874), and Thomsen later published his classical account (Thomsen, 1876 His athletic abilities, previously excellent, fell off markedly, and by the time he was 13 he had given up sport completely, though doing well at his studies. At 14 he was becoming slower physically and mentally. He gained weight rapidly and complained of lethargy and difficulty in concentrating, and his work deteriorated, so that instead of being near the top he was now near the bottom of his class.At 18 he joined the Army and was constantly in trouble on account of slowness and clumsiness. On a cold morning he was almost incapacitated. While on sentry duty he once i went stiff all over" and fell to the ground when an officer unexpectedly appeared.He next complained of frontal headaches, constipation, and occasional double vision. On investigation at that time he was puffy about the eyes, his skin was cold and dry, his pulse 55, his basal metabolic rate -25%, and serum cholesterol 470 mg. per 100 ml. A diagnosis of myxoedema was made and he was treated with thyroid. His weight decreased, the headaches became less severe, and the stiffness was less marked.When first seen at University College Hospital there was, in the absence of full details, some doubt about the diagnosis, and thyroid therapy was discontinued. A month later, on admission, there was slight puffiness around the eyes, his skin was cold and dry, his temperature 970 F. (36.10 C.), his voice low-pitched, his pulse 44, and blood pressure 130/ 80 mm. Hg. The thyroid was not clinically enlarged. The muscles were well developed, the calves appearing abnormally bulky; tone was normal and there was no wasting. The arm-, knee-, and ankle-jerks were sluggish, and direct percussion of the calf muscles and forearm extensors produced a contraction lasting about five seconds with marked grooving at the site of percussion. Following a firm handshake there was considerable delay in relaxation of the grip.Investigations.-Plasma cholesterol was 275 mg. per 100 ml. (later 370 mg.). His basal metabolic rate was -30%; radioactive iodine uptake at 24 hours was 5% of total dose. The electrocardiogram showed a rate of 39 with normal voltage curves. The blood sodium, potassium, chloride, calcium, magnesium, and inorganic phosphate were all normal. His intelligence quotient was 100.E...