Lack of efficacy of 'weighted' radiographs in diagnosing acute acromioclavicular separation.

The efficacy of "weighted" films in diagnosing grade 3 acromioclavicular (AC) sprains not evident on plain (unweighted) films was evaluated. Eighty-three pairs of radiographs, taken with and without weights, of patients with suspected AC injury were studied. The films were read in a randomized and blinded manner by a staff radiologist. Criteria for classifying AC injuries were: grade 1, less than 3 mm (or less than 50%) difference between the AC widths with a normal coracoclavicular (CC) distance; grade 2, greater than or equal to 3 mm (or greater than or equal to 50%) difference between the AC widths with a normal CC distance; and grade 3, greater than or equal to 5 mm (or greater than or equal to 50%) difference in CC distance. In only three cases (4%) did weights cause the injured CC distance to increase and thereby unmask a grade 3 injury not evident on plain films. Further evidence that weights may not reliably elucidate the degree of AC joint injury is suggested by the fact that in several cases the weights actually caused the injured and uninjured CC distance to decrease. We conclude that the use of weighted radiographs lacks efficacy in unmasking grade 3 AC sprains on radiograph and we recommend that routine use of this technique be abandoned.

Reducing the cancer risk of 239Pu by chelation therapy.

Groups of adult female C57BL/Do mice were injected intraperitoneally with graded activities of monomeric 239Pu(IV) citrate at 10 weeks of age. Beginning 3 days after plutonium injection, some mice received repeated subcutaneous injections of Zn Na3 diethylenetriaminepentaacetate (Zn-DTPA). Each injection was 37 mumol Zn-DTPA/kg body weight. To evaluate protection from bone sarcoma, brief, intermediate, or protracted chelation therapies were administered to groups of mice. The brief chelation therapy covered a 2-week period, the intermediate therapy 2 months, and the protracted therapy 1 year. The mice were followed throughout life and examined for bone sarcoma. Both skeletal dose and bone sarcoma risk were reduced by chelation. The bone sarcoma incidences in the mice given chelation treatments generally fell below the dose-response curve for the mice not given DTPA, indicating that the cancer risk was reduced more than that corresponding to the decreased skeletal dose. This results suggests that Zn-DTPA preferentially removed Pu from the most carcinogenic locations in the skeleton, such as on bone surfaces near living cells.

243,244Cm studies in C57BL/Do mice.

Three groups of C57BL/Do mice were injected with different activities of 243,244Cm so that the long-term biological effects could be evaluated. The biological retention, R, of injected curium in the skeleton at t days after injection could be represented by the equations R = 0.245e-0.000379t and R = 0.208e-0.000494t for male and female mice, respectively. Effective skeletal retention equations were used to calculate the cumulative mean skeletal dose in rad at 140 days before death in each group of mice. The primary objective of this study was to determine the relative biological effectiveness (RBE) of 243,244Cm compared to 226Ra, using bone sarcoma induction as the end point. Combined data (bone sarcomas per 10(6) mouse-rad) for male and female mice permitted the RBE value +/- SD for 243,244Cm to be calculated as 4.4 +/- 1.8 compared to 1.0 for 226Ra. A comparison of RBE values form a previous study in this mouse strain and the value for 243,244Cm from this study suggests that the trivalent actinides 241Am, 243,244Cm, and 249Cf are about three times less effective for bone sarcoma induction than 239Pu.

Gluten challenge in treated coeliac disease.

Thirty-two children with a past diagnosis of coeliac disease were reinvestigated by means of gluten challenge. They had received a gluten-free diet for a mean period of 6-5 years (range 0-25-11-0) before gluten challenge, and had a mean age of 9-9 years (range 3-0-15-3) at the onset of challenge. Small intestinal biopsies were performed before and after the gluten challenge (at least 10 g natural gluten per day for 3 months in the majority) and, as judged by light microscopy and morphometric techniques, coeliac disease was confirmed in 25 (78%) of the 32 patients; challenge was continued in the remaining 7 for a total period of 2 years when biopsies were repeated in 6 children and all were normal. Serum and RBC folate, serum iron, Hb level, and clinical symptoms were unpredictable variables in identifying children who developed gluten-induced enteropathies. The social and emotional effects of gluten challenge are discussed. The results highlight the importance of gluten challenge and intestinal biopsy in the diagnosis of coeliac disease and strongly suggest that a normal biopsy after a 3-month gluten challenge (as described above) excludes coeliac disease.