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1 The serum lithium concentration was measured before dosing, and at 2, 4, 6, 8, 10, 20, 22, and 24 h after three proprietary preparations of lithium carbonate (Camcolit, Phasal or Priadel). 2 A total of twenty-eight studies were performed on eleven patients. In seven studies the patients received Camcolit, in ten studies patients received Priadel and in eleven the patients took Phasal. 3 The dose of each preparation was adjusted during a 10 week run-in period to maintain the serum lithium within the normal therapeutic range (0.6-1.2 mmol/1). Five patients received one lithium preparation, one patient received three lithium preparations and five patients received four lithium preparations consecutively. 4 After a single daily dose of Phasal and Priadel, the serum lithium remained within the therapeutic range for 24 h. 5 After a single daily dose of Camcolit, the serum lithium remained within the therapeutic range for only 12 h. 6 After three doses of Camcolit (given at 0.800 h, 12.00 h, and 18.00 h) each day, the serum lithium was maintained in the therapeutic range for 24 h.

A flame photometric method using atomic fluorescence (AFS) for cadmium (Cd) estimation is described and applied to the measurement of Cd in blood. The AFS system employs a modified, low cost atomic absorption spectrophotometer, with a high intensity Cd light source provided by an electrodeless discharge tube, excited in a thermostatted microwave cavity. The analytical sensitivity of the technique is sufficient to permit dilution (1 in 5) of blood, before aspiration into the air-hydrogen flame. The method is rapid (25 duplicates/hour), and gives acceptable precision (coefficient of variation within batch 2-5%, between batch 8-1%). The method was applied to a reference population and to three different groups of industrial workers. The reference population had a mean blood concentration of 35-1 nmol Cd/litre. Group 1 (general categories of worker) had 65-2 nmol Cd/1, Group 2 (demolition workers), 137-9 nmol Cd/1, and Group 3 (shipbreakers), 105-9 nmol Cd/1. There was a relationship between increases in blood Cd and in blood Pb which was statistically significant for Group 3.

The optimization of the conditions of use of three commercial carbon-furnace atomic-absorption spectrometers for the determination of cadmium in urine is described. The performance of each instrument is evaluated with respect to sensitivity, precision, detection limit and accuracy. All three instruments could be used for the determination of cadmium at levels greater than 0.2 mug/l. in the urine of exposed and "normal" subjects. A sample can be analysed in duplicate in 15 min. No sample pretreatment is required.

The trace element content of kidneys has been documented in very few international centres. Significant differences can be demonstrated between the cortical and medullary levels of calcium, zinc and cadmium. For the West of Scotland the values for the latter are similar to those found in Scandinavia. There are significantly higher cadmium contents in subjects who smoke and who have evidence of ischaemic heart disease.

An ultrasonic Duplex scanner was used to estimate the site and degree of extracranial arterial disease in two groups of patients with asymptomatic bruits. In the first 100 patients only the extent of disease was assessed with 37% of the sides with bruits having high-grade stenoses (greater than 50% diameter reduction) and one-half having lesions which narrowed the internal carotid artery by less than 50%. Seven percent were found to be normal. The remaining 6% had occlusion of the internal carotid artery. In a second group of 81 patients, the effect of the reported findings of the Duplex scan on patient management was reviewed. Only 13 patients underwent angiography and 11 of these were in patients with high-grade stenoses. Five carotid endarterectomies were performed and in each case, the patient had bilateral high-grade lesions. The implications of this diagnostic approach are discussed as well as the need for prospective studies of patients who present with an asymptomatic bruit.

The occurrence of stroke associated with coronary artery bypass operations is approximately 2%. In an attempt to reduce this incidence some centers have proposed carotid thromboendarterectomy for symptomatic and asymptomatic carotid arterial disease in patients undergoing a coronary artery bypass operation. To obtain a better understanding of the incidence of carotid occlusive disease in candidates for the coronary bypass operation and to evaluate the practical use of a noninvasive method to screen patients preoperatively, we evaluated 102 patients preoperatively with an ultrasonic Duplex scanner; 24 studies were requested on the basis of either previous neurologic problems or the presence of a bruit and 78 patients were evaluated as part of a study protocol. In the unrequested group 6% (5/78) of the patients had a stenosis of 50% diameter reduction or more. In the requested group 54% (13/24) had a stenosis of 50% diameter reduction or more. In the postoperative phase one stroke and one transient ischemic attack were noted among the unrequested group and none in those suspected of having carotid disease on clinical grounds. Neither affected patient had a high-grade stenosis. There is little evidence to support the contention that noninvasive screening of patients free of symptoms or signs of carotid disease prior to coronary artery bypass operation is a valuable method of screening for patients who will sustain a focal neurologic event.

Accidental exposure of 25 patients on continuous ambulatory peritoneal dialysis to a high aluminium level in the dialysate for a month provided an opportunity to investigate the interrelation between the metabolism of parathyroid hormone (PTH), calcium, and aluminium. After exposure to the high-aluminium dialysate, the mean serum aluminium had risen from 1.85 to 7.11 mumol/l and serum calcium from 2.27 to 2.44 mmol/l, and serum PTH had fallen from 744 to 580 ng/l. After a further 2 months, during which time the dialysate was aluminium-free, the mean serum aluminium and calcium fell to previous levels. There were no changes in calcium or vitamin-D therapy which could have influenced these results. The rise in serum calcium and fall in PTH during a period of aluminium toxicity strongly support the hypothesis that aluminium suppresses PTH through an elevation of serum calcium.

A method for the neutron activation analysis of copper in biological material is described and applied to the diagnosis and management of four cases of Wilson's disease. Results obtained for serum and urine are in agreement with values obtained by established colorimetric techniques. The method described can estimate 10(-9) g. copper to within 10% and this sensitivity has allowed the determination of copper from biopsy material such as liver, spleen, hair, and nail.