Profiles of faecal output of rare earth elements and stable isotopic tracers of iron and zinc after oral administration.

The objectives of this study were to confirm the non-absorbability and the reproducibility of faecal excretion kinetics of orally administered rare earth elements, and to investigate the excretion profiles of rare earth elements and stable isotopic tracers of Fe and Zn to establish the extent to which rare earth element markers duplicate the behaviour of isotopic tracers. Two investigations were performed: (1) six healthy subjects consumed a solution containing five rare earth elements in amounts varying from 1 to 10 mg; (2) seven healthy subjects were given a standard solution labelled with Sm marker and (57)Fe tracer, and a meal labelled with Yb marker and (58)Fe and (70)Zn tracers. Individual faecal samples were collected and analysed to determine recoveries of rare earth elements and unabsorbed isotopic tracers. The mean values for recoveries were 94.1 (sd 4.5) % for the five rare earth elements, and 103 (sd 3.0) % and 99.8 (sd 2.8) % for Sm and Yb respectively. For Fe consumed with the solution, excretion kinetics of the rare earth element marker and unabsorbed tracers with cumulative collections of the first two and three faecal samples were identical, but endogenous excretion of Fe was significant in stools collected after the third. For Fe and Zn consumed with the meal, the excretion kinetics for the first two individual faecal samples and composites of sequential outputs were identical. Rare earth elements can be used as markers in studies of measurement of absorption. The dose of tracer required for the measurement of absorption would be reduced proportionally to the reduction of the period of faecal sampling, so that studies with stable isotopes would be more economical, thus enabling epidemiological investigations.

Iron for the suckling.

Knowledge of the metabolism of iron by young infants is incomplete but combining practical studies based on detecting the onset of iron depletion with isotopic studies of iron economy may improve our understanding of iron metabolism in infants and our strategies for ensuring their iron supply. The iron accumulated by the fetus is enough to delay the risk of iron deficiency until four, and two months of age in term and preterm infants respectively. Breast fed term infants may not need extra iron until they are six months or older; but whereas low iron formulas are adequate for other infants until about four months of age, thereafter infants need extra iron which can be provided effectively in iron fortified formulas. Breast fed low birth weight infants need iron supplements from two months of age but those fed specific low birth weight formulas which are iron fortified should not need extra iron.

Uptake and excretion of inorganic mercury in the lobster Homarus gammarus (L.) White 1847: long-term effects of exposure to low levels of the metal.

The uptake and accumulation of inorganic mercury by lobsters, from seawater containing levels of 10 to 100 ppb, was studied over periods of up to 50 days, using radiochemical neutron activation analysis. These results were amplified by the use of radioisotope tracer experiments. It was found that the gills and the green glands accumulated the most mercury and that the metal could be excreted via the urine. Histological studies showed that long-term exposure to mercury resulted in progressive necrosis of the green glands, whereas other organs were unaffected.

Value of chest radiography in excluding traumatic aortic rupture.

A retrospective review of chest radiographs from 205 patients with blunt chest trauma who also underwent aortography was performed. Forty-one of the 205 had aortographically proved aortic rupture. Discriminant analysis of 16 radiographic signs indicated that the most discriminating signs were loss of the aorticopulmonary window, abnormality of the aortic arch, rightward tracheal shift, and widening of the left paraspinal line without associated fracture. No single or combination of radiographic signs demonstrated sufficient sensitivity to indicate all cases of traumatic aortic rupture on plain chest radiographs without the performance of a large number of aortographically negative studies. The bedside anteroposterior "erect" view of the chest proved far more valuable than the supine view in detecting true-negative studies. Despite significant reader variability in the interpretation of the various radiographic signs, in general the analysis confirmed the role of chest radiography in this clinical situation, but suggests that its most beneficial use is in excluding the diagnosis and eliminating unwarranted aortography rather than in predicting aortic rupture.

Abdominal CT in the staging of small-cell carcinoma of the lung: incidence of metastases and effect on prognosis.

CT studies of the abdomen performed on 72 patients with small-cell carcinoma of the lung were retrospectively reviewed to assess the role of abdominal CT in staging. Forty-four of the 72 patients had extensive disease, defined as disease extending beyond the confines of one hemithorax, plus or minus mediastinal or ipsilateral supraclavicular disease or ipsilateral pleural effusion. Initial-staging abdominal CT revealed one or more sites of metastatic disease in 26 (59%) of these 44 patients, while 18 patients had normal initial CT examinations. Statistical analysis of patients with extensive disease revealed a significant increase in complete therapeutic response (p = .0054) and in the length of survival (p = .001) among those who had extensive disease without abdominal metastases as compared with those who had abdominal metastases on their initial abdominal CT examination. The development of new or recurrent abdominal metastases in general or in specific organs on follow-up scans obtained in 35 patients did not significantly decrease their survival time as compared with that of patients without such metastases. Our findings suggest that CT of the abdomen is beneficial in the initial staging of patients with small-cell carcinoma of the lung and provides prognostic information concerning response to therapy and length of survival.

Computed tomography of the liver after dearterialization and intraarterial chemotherapy.

Hepatic dearterialization by ligation of the main hepatic artery followed by local intraarterial chemotherapy was performed in 24 patients with clinically isolated but unresectable hepatic metastasis after local resection of carcinoma of the colon. Computed tomography of the abdomen and laboratory parameters were used both to stage and follow-up these patients. Computed tomography changes following dearterialization and chemotherapy of the liver are described. Computed tomography is a valuable technique for both staging and follow-up this group of patients.

Gray-scale (B-mode) sonography of the maxillary sinus.

Gray-scale sonographic examination of the maxillary sinuses of five normal volunteers and 12 patients with maxillary sinus disease was performed and correlated with other radiologic imaging modalities, clinical follow-up, and, in two cases, surgical findings. B-mode scanning is a rapid, potentially useful, nonionizing diagnostic modality for determining whether the maxillary sinuses contain fluid or are normally aerated. Sonography may also demonstrate mucosal thickening, focal soft tissue masses, and complex collections.

Computed tomography of the chest in small cell lung cancer: potential new prognostic signs.

Computed tomography (CT) of the chest was performed as part of the initial and subsequent staging evaluations in 33 patients with small cell lung carcinoma. In 25 of the 33 patients, CT demonstrated findings not observed on standard radiography. Eleven of the 33 would have been staged higher using CT. Before treatment, CT revealed more mediastinal and nodal involvement than conventional films. After chemotherapy, CT demonstrated areas of residual or early recurrent disease in nine of 28 patients that were not apparent on chest films. Initially thickened pericardium in patients with limited disease and persistent bronchial narrowing after chemotherapy were demonstrated to be associated with early relapse in the chest and short survival. These initial data suggest that the CT scan, in addition to more accurately assessing the extent of disease, can provide a new risk classification for early chest relapse. Initial thickened pericardium in limited disease and continued bronchial narrowing after chemotherapy may allow patient selection for future treatment trials with radiation as an adjuvant to chemotherapy.

Computed tomography for localization of parathyroid adenomas.

Fourteen consecutive patients with the clinical diagnosis of primary hyperparathyroidism had computed tomography (CT) preoperatively to evaluate the use of CT in localizing parathyroid adenomas. The patients were scanned from above the level of the thyroid cartilage to the bifurcation of the trachea. Computed tomography correctly identified, prospectively, the site of the adenoma in 7 of 14 patients, including one adenoma that was ectopic in location. Nine of these patients also had barium esophagrams, and this study was accurate in only three of the nine. Our study suggests that CT may be beneficial in the preoperative localization of parathyroid adenomas, particularly those in ectopic locations.