How effective is sodium fluoride as a preservative of blood glucose? We compared changes in glucose concentration in fluoride-treated blood specimens with those of heparin-treated specimens. The former declined rapidly during the first hour; thereafter the rate of decrease was slower, and after 4 h the glucose concentration in the blood samples remained stable for up to three days. In contrast, the glucose concentration in the heparin-containing samples declined continuously. During the first hour, however, the rates of decline in the two types of samples were similar. Evidently sodium fluoride takes effect slowly but effectively in preserving glucose in blood for at least three days. Its use, however, is unnecessary if the concentration of glucose is to be measured within the first hour after sampling.

Disturbance of vision commonly accompanies hypoglycaemia. This study was designed to investigate the nature of the visual disturbance, the blood glucose threshold at which the disturbance occurred and the physiological basis. Measurements were made of the corrected visual acuity, colour vision (100 Hue test), visual evoked potentials (VEP), electroencephalography (EEG) frequency analysis and psychometry (digit recall) during stepwise induction of controlled hypoglycaemia produced by an intravenous insulin infusion. Six male volunteers and five insulin-dependent diabetic subjects were studied. During hypoglycaemia corrected visual acuity was unchanged. Colour vision was significantly impaired. Baseline VEP were normal in both groups but significantly prolonged during hypoglycaemia (mean increment 10.8 ms) and increased by greater than 5 ms in nine out of 11 subjects. Quantitative EEG analysis demonstrated slowing with a power density spectral shift from fast alpha to slow alpha, theta and delta which correlated with VEP latency and amplitude changes. The findings have clinical implications. A deterioration in colour vision is likely to impair the ability to read reagent strips by eye. VEP measurements in diabetic patients are likely to be misleading if hypoglycaemia is present; EEG changes are a sensitive index of cortical dysfunction during hypoglycaemia and provide a theoretical basis for developing a portable device to detect early hypoglycaemia.

Dual phase contrast enhanced spiral computed tomography (DPSCT) has the potential to improve detection of small insulin secreting islet cell tumours of the pancreas. Seven patients with biochemically proven insulinoma, who had previously undergone a range of negative radiological procedures, were referred for DPSCT. Images of the pancreas were obtained using 3 mm collimation in the arterial and arteriovenous perfusion phase following the rapid injection of contrast medium. Six tumours were localized in seven patients. The six insulinomas identified on DPSCT ranged in size from 6 mm to 18 mm and were located in the uncinate process (2), head (1), neck (2) and body (1). All six tumours were detected in the arterial phase and four in the arteriovenous phase. The four insulinomas detected on both perfusion phases were more conspicuous in the arterial phase in three patients and more conspicuous in the arteriovenous phase in one patient. In conclusion, high resolution arterial phase acquisition of the pancreas is very valuable in the detection of small insulinomas.

Clozapine may induce sympathetic hyperactivity.

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Summary. Acromegaly patients are known to have an increased risk of malignancies, especially colonic adenocarcinoma. This may be as a result of the growth-stimulating effect of growth hormone (GH). The clustering of leukaemia in children treated with GH has also caused concern. There have been a few reports of leukaemia in acromegaly patients. We report two patients with acute lymphoblastic leukaemia and one patient with acute myeloid leukaemia among 106 acromegaly patients treated over a 15-year period. Two of the cases received radiotherapy as part of their treatment. Adjusted for age and follow-up years, the incidence of leukaemia in this cohort is significantly higher than the general population. The incidence is also higher than would be expected as a result of radiotherapy alone, suggesting that GH may play a synergistic role.

Left adrenalectomy has been performed previously via anterior, posterior, loin or thoracoabdominal approaches. In the classical transabdominal approach the left adrenal gland is resected following either mobilization of the spleen with the tail of the pancreas or after entering the lesser sac, mobilizing the inferior border of the pancreas off the adrenal gland. This report describes laparoscopic left adrenalectomy, in a patient with Conn's syndrome, performed by a new approach via the root of the left transverse mesocolon.