Prevention of transfusion-associated Chagas' disease: efficacy of white cell-reduction filters in removing Trypanosoma cruzi from infected blood

BACKGROUND : Transfusion-associated Chagas' disease (TA-CD) is a worldwide problem. Measures adopted to prevent TA-CD include the clinical and serologic screening of blood donors and/or the inactivation of Trypanosoma cruzi present in collected blood, using gentian violet as the trypanocidal agent. This study investigated the efficacy of white cell-reduction filters in removing T. cruzi from infected blood. STUDY DESIGN AND METHODS : Human blood was contaminated with 2 or 150 T. cruzi parasites per mL and then left unfiltered or filtered with white cell-reduction filters that provided either 2, 3, or 6 log10 white cell removal. The efficacy of the parasite removal of these filters was evaluated by microscopic enumeration of active forms of T. cruzi both in vivo and in vitro. The in vivo experiments were done in Swiss mice that had been intraperitoneally inoculated with T. cruzi-infected human blood. The in vitro experiments were performed with fresh human blood that had been deliberately contaminated with T. cruzi. RESULTS : The number of parasites seen in mice inoculated with unfiltered blood containing 2 or 150 parasites per mL was significantly higher than the number of parasites seen in mice inoculated with blood from the same sample, but filtered with white cell-reduction filters providing 3 or 6 log10 white cell removal. Fifty to 70 percent of the mice given T. cruzi-infected (2 parasites/mL) filtered blood did not develop T. cruzi infection. In vitro, the use of white cell-reduction filters, providing 2, 3, or 6 log10 white cell removal, significantly reduced the number of parasites seen in culture. CONCLUSION : The present experimental data provide evidence that white cell-reduction filters are effective in reducing the number of parasites in T. cruzi- infected blood and that this efficacy depends, in part, on the concentration of parasites in the artificially infected blood. Properly designed clinical studies of known carriers of T. cruzi must be conducted to determine whether the use of white cell-reduction filters may be an alternative method of reducing the incidence of TA-CD.     

Recurrent colorectal carcinoma: evaluation with barium enema examination and CT

The efficacy of the barium enema examination and abdominal computed tomography (CT) was investigated in 81 patients who had undergone operation for colorectal carcinoma. Recurrent disease was found in 52 patients and was divided into local (anastomotic and perianastomotic) and remote (distant and hepatic metastases) types. In 32 patients with locally recurrent carcinoma, the sensitivity of the barium enema examination was 88%; for CT it was 69%. Conversely, the barium enema examination was not useful for detecting remote metastases shown on CT, which disclosed disease at one or more sites in 47 (90%) of the 52 patients. CT best evaluated recurrences remote from the anastomosis, pelvic recurrences in patients with colostomies, and hepatic metastases. Barium enema examination and CT were therefore found to be complementary modalities.     

Meniscal tears: pathologic correlation with MR imaging

Menisci from 12 autopsies and above-knee amputations were imaged with magnetic resonance (MR) at 1.5 T and then sectioned for gross and histologic examination. A histologic staging system was developed and showed a one-to-one correlation with corresponding grades of MR signal intensities. Histologic stages 1 and 2 represented a continuum of degeneration culminating in stage 3 fibrocartilaginous tears, seen most frequently in posterior-horn segments of the medial meniscus. Correlation of histologic stages with MR signal intensity allows for an improved diagnostic reading of MR images.     

Cystic lung disease associated with eosinophilic granuloma and tuberous sclerosis: air trapping at dynamic ultrafast high-resolution CT.

Thin-walled lung cysts can occur in association with advanced pulmonary eosinophilic granuloma and lymphangioleimyomatosis (LAM). In LAM, cysts occur as an isolated abnormality or in association with tuberous sclerosis. The cause of these cysts is unclear, but some investigators have postulated that they result from air trapping. To determine if lung cysts in these two diseases are associated with air trapping, the authors performed dynamic ultrafast high-resolution computed tomography (DUHRCT) during forced expiration in two patients (one with eosinophilic granuloma and one with tuberous sclerosis) with lung cysts and correlated the results with results of pulmonary function tests. DUHRCT demonstrated focal and diffuse air trapping; in some lung regions, a less than normal increase in lung attenuation during forced exhalation was evident. These studies do not allow a conclusion regarding the mechanism of cyst formation in eosinophilic granuloma and LAM-tuberous sclerosis, but they confirm the association between lung cysts and morphologic findings of air trapping.     

A comparison of isometric strength and dynamic lifting capacity in men with work-related low back injuries

Job classification, return to work status, and job placement are determined by the results of lifting capacity tests. Lifting capacity is often assessed by maximum static or dynamic physical exertions. The purpose of this study was to compare maximum isometric lifting strength with maximum dynamic lifting capacity in subjects with work-related low back injury. Twenty-seven men performed five dynamic lifting tasks and two isometric strength tests. The mean Pearson product-moment correlation between maximum isometric lifting strength measurements and maximum dynamic lifting capacity measurements was .51 with a range of .30–.73. The results indicate low to moderate associations between isometric strength measurements and lifting capacity suggesting that estimates of functional lifting capacity should not be based on static measurements alone. Dynamic lift tests are often a better simulation of the task being assessed and may be more appropriate for a back-injured population.