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- Hellman, Per, et al.
(författare)
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Positron emission tomography with 11C-methionine in hyperparathyroidism
- 1994
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Ingår i: Surgery. - 0039-6060 .- 1532-7361. ; 116:6, s. 974-981
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Positron emission tomography (PET) has not been evaluated for preoperative localization and functional characterization of the parathyroid tissue in hyperparathyroidism. METHODS: Images of the neck and upper mediastinum of 23 patients with hyperparathyroidism were obtained by PET after intravenous administration of 400 to 800 MBq L-[methyl-11C]-methionine. The investigation was repeated in six patients after Na2-ethylenediamine tetraacetic acid infusion, whereby stable 65% to 157% rise in intact serum parathyroid hormone values was attained. RESULTS: Parathyroid surgical procedure revealed single (21 patients) or two enlarged parathyroid glands (two patients) that were characterized as chief cell adenoma (n = 13), hyperplasia (n = 10), or carcinoma (n = 2) and weighed 80 to 6000 mg. Twenty (80%) of these glands were localized by PET. The remaining examinations (20%) were false negative and mainly encompassed small parathyroids in juxtathyroid position. Among 15 patients undergoing parathyroid reoperation true-positive localizations were obtained for 87% of the glands. The images displayed lower tracer uptake in residual thyroid lobes (n = 40), esophagus, and cervical vertebrae. Na2-ethylenediamine tetraacetic acid infusion failed to enhance parathyroid uptake values. Ultrasonography, computed tomography, technetium-thallium scintigraphy, and venous sampling revealed 25% to 53% of the pathologic parathyroid tissues of the patients undergoing reoperation and was largely complementary to PET. CONCLUSIONS: The results suggest that PET may provide novel possibilities for the imaging of pathologic parathyroid glands in hyperparathyroidism.
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| 2. |
- Westerberg, E., et al.
(författare)
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Extracellular levels of quinolinic acid are moderately increased in rat neostriatum following severe insulin-induced hypoglycaemia
- 1990
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Ingår i: Acta Physiologica Scandinavica. - : Wiley. - 0001-6772 .- 1365-201X. ; 138:3, s. 417-422
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Tidskriftsartikel (refereegranskat)abstract
- Extracellular concentrations of the brain metabolite quinolinic acid, an endogenous excitotoxin, were monitored by microdialysis in rat neostriatum and hippocampus/cortex during and following a 30-min period of insulin-induced hypoglycaemia. During hypoglycaemia-induced isoelectricity, extracellular levels of quinolinic acid in the striatum (basal value, 1.1 ± 0.3 pmol per 30-μl fraction) were elevated 1.7 times as compared to the control period. Thirty to ninety minutes following hypoglycaemia a significant increase in extracellular quinolinic acid to 2.2 times basal level was noted. After 2 h recovery, the beginning of neuronal necrosis was observed in the dorsolateral striatum. Implantation of the dialysis probe did not influence the extent of neuronal damage. No changes in extracellular quinolinic acid levels were observed in the hippocampus/cortex. The data indicate the following a severe hypoglycaemic insult vulnerable striatal cells are exposed to hyperphysiological extracellular quinolinic acid concentrations over an extended period of time. Considering the pronounced susceptibility of rat striatal neurons to the toxin, the small but prolonged elevation in the extracellular levels of quinolinic acid could be of significance for the development of delayed neuronal death in hypoglycaemia.
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