Effects of glutathione depletion, chelation and diuresis on iron nitrilotriacetate-induced lipid peroxidation in rats and mice

1. Rats and mice dosed with iron nitrilotriacetate (FeNTA) i.p. (2-12 mg Fe/kg) showed evidence of lipid peroxidation as indicated by increased exhalation of ethane and increased malondialdehyde formation in liver and kidney. 2. Buthionine sulphoximine (BSO) administered i.p. to rats and mice decreased the total glutathione (GSH) content of liver and kidney. When the rodents were pretreated i.p. with BSO prior to injection of FeNTA the increases in ethane exhalation, and in liver and kidney malondialdehyde production, were greater than with FeNTA alone, and the total GSH of liver and kidney were decreased. 3. Diuresis produced by i.p. administration of furosemide to mice substantially decreased the ethane exhalation resulting from FeNTA administration, had a lowering effect on kidney MDA, but had no significant effect on liver MDA production. 4. Similarly, desferrioxamine beta-mesylate administered i.p. to mice markedly decreased the ethane exhalation and kidney MDA production resulting from FeNTA administration.     

The macrophage electrophoretic mobility (MEM) test for malignant disease. Further clinical investigations and studies on macrophage slowing factors

This paper describes further confirmation of the successful application of the macrophage electrophoretic mobility (MEM) test to the detection of malignant disease. Results from fifty-one patients and eighteen controls are presented. The apparatus and technique used for the measurement of macrophage electrophoretic mobility differed from those previously used in other investigations. Further information is presented on the nature and behaviour of macrophage slowing factor(s), and experiments concerning the possible use of cells other than guinea-pig macrophages as indicators of slowing factor production are also described.     

The induction of autoxidative tissue damage by iron nitrilotriacetate in rats and mice

Iron nitrilotriacetate (FeNTA) is a potent initiator of lipid peroxidation, and, when injected intraperitoneally into mice, it greatly increased ethane and pentane exhalation within 30 min. The time course and dose-response of the exhalation of ethane were studied and compared with the increase in tissue malondialdehyde (MDA) production. Production of MDA was greater in mouse kidney than liver and correlated better with the exhalation of ethane. In rats FeNTA also increased ethane exhalation and MDA, but the rat was less susceptible than the mouse to FeNTA toxicity. MDA production was greater in rat liver than kidney and both correlated well with ethane exhalation (r = 0.97 and 0.98, respectively). Renal proximal tubular damage was observed histologically 35 min after mice were given FeNTA, but in rats the lesion appeared 24 hr after dosage. Histopathological assessment of kidney damage at these times showed fair correlation with ethane exhalation in mice (r = 0.73) and rats (r = 0.62), respectively. Activities of kidney brush-border marker enzymes were decreased in mice, 35 min after FeNTA administration, and showed a similar trend in rats. Some rats also showed periportal necrosis of the liver, 24 hr after FeNTA administration. The very rapid onset of autoxidative damage suggests that FeNTA itself is the causative agent rather than subsequently formed, less reactive complexes, such as transferrin. The site of damage in the kidney tubule is consistent with the region of concentration of filtered FeNTA. It is suggested that FeNTA supports the formation of superoxide ion from dissolved oxygen and may be responsible for the subsequent formation of hydroxyl radical which initiates lipid peroxidation. The species difference between rat and mouse may be due to the greater resistance of the rat kidney to FeNTA-induced autoxidative damage.     

The effect of adenoid and tonsil surgery on nasalance.

The change in nasalance following adenoidectomy, tonsillectomy and adenotonsillectomy was studied in 44 children. A subjective assessment of each child's naso-pharyngeal airway was made preoperatively based on a questionnaire completed by the parents. There was no significant change in the nasalance of children following adenoidectomy, but there was a significant increase in the nasalance following tonsillectomy (P = 0.02) and after adenotonsillectomy (P = 0.001). There was no relationship between the change in nasalance and the adenoid volume removed at operation. There was good agreement between the parental subjective assessment of the naso-pharyngeal airway and the preoperative nasalance score, with the best correlation in the adenoidectomy group (r = -0.8) and the adenotonsillectomy group (r = -0.7). Nasalance is more closely related to the size of the naso-pharyngeal airway than to the actual adenoid volume, and measurements of nasalance are of no benefit in predicting adenoid volume. Tonsillectomy had a significantly greater effect on nasalance than adenoidectomy, and adenotonsillectomy had the greatest effect. Further studies are needed to relate nasalance to the size of the naso-pharyngeal airway, but it appears to relate well to the subjective assessment of the airway and may be of use in patient selection for surgery.     

Superficial- and deep-tissue temperature increases in anesthetized dogs during exposure to high specific absorption rates in a 1.5-T MR imager

Superficial- and deep-tissue heating was measured in five dogs during high-specific-absorption-rate radiofrequency (RF) irradiation to see whether significant temperature changes could be produced by a 1.5-T clinical magnetic resonance imager. The RF power output employed was 6.3 times that required for routine imaging. Temperature probes were placed in both deep and superficial tissues, and temperatures were recorded before, during, and after exposure. In each dog, there was a linear temperature increase of several degrees during RF exposure; the maximal average change was 4.6 degrees C in the urinary bladder. The temperature increase was slightly greater in deep tissues than in superficial tissues. The calculated specific absorption rate, based on the temperature change, averaged 7.9 W/kg for all five dogs. These findings argue for continued caution in the design and operation of imagers capable of high specific absorption rates, particularly when they are used for imaging infants or patients with altered thermoregulatory capability.     

Body proportions in precocious puberty

Sitting height (SH) and sub-ischial leg length (SLL) were measured in 10 boys and 16 girls with precocious puberty; the patients were aged from 1.5 to 13.4 years at the time. Standard deviation scores (SDS) calculated for chronological age and bone age showed higher scores for SH than for SLL in all but two patients, both girls: the differences between the SDS for SH and SLL were more marked in the boys. The findings indicate that growth of the trunk is usually greater than growth of the legs in precocious puberty, particularly in boys.