Differential effects of high dietary levels of vitamin A on the vitamin E-selenium nutrition of young and adult chickens

Experiments were conducted to determine the nature of the interaction of high levels of vitamin A and vitamin E-selenium nutrition in the chicken. Results showed that chicks were protected from the vitamin E-selenium deficiency disease exudative diathesis (ED) by a high dietary level of vitamin A (1.0 X 10(6) IU/kg) which moderately depressed growth. A greater concentration (1.5 X 10(6) IU/kg) of vitamin A in the diets of hens fed a low vitamin E diet hastened their depletion of plasma tocopherols and increased plasma glutathione peroxidase (GSH-px) activity. At hatching the progeny of vitamin A-fed hens were severely depleted of plasma tocopherols but had normal plasma GSH-px activities. They showed increased susceptibility to ED when fed selenium-deficient, vitamin E-free diets for 2 weeks. Absorption studies using ligated duodenal loops or oral doses indicated that high-level dietary vitamin A promoted the enteric absorption of selenium but interfered with the absorption of vitamin E. The dual nature of these effects was related to the ED-protective influence of vitamin A when fed to chicks, and the ED-stimulative influence on progeny when vitamin A was fed to dams.     

CT abnormalities of the pituitary in hyperprolactinaemic women with normal or equivocal sellae radiologically

Sixteen young women with hyperprolactinaemia and normal or equivocal sella in radiographs underwent computed tomography using a Siemens Somatom II. In all but one case an abnormality was found. The sella was full in seven and partially empty in nine. A tumour was visible in six of the full and in four of the partially empty sellae. All but one of the 10 tumours was unilateral, and in seven the pituitary stalk was deviated away from the tumour. After administration of intravenous contrast (Urografin) four tumours showed diffuse enhancement, four ring enhancement, and two enhanced less than adjacent normal pituitary tissue. Two of the tumours have been subsequently shown histologically to be prolactinomas. Prolactin response to thyrotrophin-releasing hormone predicted a tumour in seven out of eight with visible tumours but also in three out of four without visible tumours; using metoclopramide, a tumour was predicted in six out of seven with tumours, but again in three out of four without visible tumours. Such results question the value of dynamic tests for the discrimination of tumours. We conclude that practically all women with sustained hyperprolactinaemia and a normal or equivocal sella radiologically have pituitary disease.     

Lateralization of human temporal lobe epilepsy by 31P NMR spectroscopic imaging at 4.1 T

OBJECTIVE: To compare the phosphorous metabolite ratios in the mesial temporal lobe of healthy volunteers (n = 20) with the corresponding ratios in patients with temporal lobe epilepsy (n = 30) using 31P NMR spectroscopic imaging and to lateralize the seizure focus in temporal lobe epilepsy patients using various phosphorous metabolite ratios-phosphocreatine to inorganic phosphate (PCr/Pi), PCr to adenosine triphosphate (PCr/gamma-ATP), and (gamma-ATP/Pi)--and to compare with clinical lateralization results. METHODS: All 31P NMR spectroscopic imaging studies were performed on a high-field, 4.1 T, whole-body NMR spectroscopic imaging system using a 31P/1H double-tuned volume coil. RESULTS: We found an average reduction of 15% in the PCr/Pi and gamma-ATP/Pi ratios compared with the corresponding ratios in healthy volunteers in the entire mesial temporal lobe, and more than a 30% reduction in these two ratios in the anterior region of the epileptogenic mesial temporal lobe. These ratios were also reduced significantly in the ipsilateral lobe when compared with their corresponding values in the contralateral lobe. In patients we lateralized the seizure focus, based on these 31P NMR data, and compared the results with the clinical lateralization. The lateralization based on either the PCr/Pi or the gamma-ATP/Pi ratio yielded a correspondence of 70 to 73% with the final clinical lateralization. In the subgroup of patients (n = 9) that needed intracranial EEG for the presurgical lateralization because of inconclusive results from the noninvasive methods, a 78% correspondence was found with the 31P NMR-based lateralization, whereas MRI provided a correspondence of only 33%, and scalp EEG provided a correspondence of only 56%. CONCLUSIONS: These results suggest the utility of adding the 31P NMR method to the group of noninvasive modalities used for presurgical decision making in temporal lobe epilepsy patients.