Second-screening mammography: one versus two views per breast

To compare the advantages of one-view versus two-view second-screening (follow-up) mammography, oblique and craniocaudal projection mammograms from 1,000 consecutive asymptomatic women who had prior normal baseline studies were reviewed retrospectively, first with only the oblique images, then with the oblique and craniocaudal views. In women with dense breasts, one-view (oblique only) readings resulted in abnormal interpretations four times more frequently (53 cases, 5.3%) than two-view readings (13 cases, 1.3%). The induced cost from these abnormal interpretations would have more than offset the small savings in operating expense associated with one-view screening. In contrast, four times fewer abnormal one-view interpretations (13 cases, 1.3%) were made in women with primarily fatty breasts, in whom superimposition of dense tissue on images is not as frequently a problem. In these women, considering only cost, it may be reasonable to obtain a single mediolateral oblique projection for follow-up screening mammography. However, the issue of whether to implement such an approach remains unresolved, because the sensitivity of one-view versus two-view second screening in the detection of breast cancer has not yet been determined.     

Critical analysis of radiologist-patient interaction

A critical incident interview technique was used to identify features of radiologist-patient interactions considered effective and ineffective by patients. During structured interviews with 35 radiology patients and five patients' parents, three general categories of physician behavior were described: attention to patient comfort, explanation of procedure and results, and interpersonal sensitivity. The findings indicated that patients are sensitive to physicians' interpersonal styles and that they want physicians to explain procedures and results in an understandable manner and to monitor their well-being during procedures. The sample size of the study is small; thus further confirmation is needed. However, the implications for training residents and practicing radiologists in these behaviors are important in the current competitive medical milieu.     

Aging of the diaphragm: a CT study

To determine the normal morphologic evolution of the diaphragm with aging and to correlate age-related changes with other indicators of physical condition--such as skeletal muscle status, obesity, presence of pulmonary emphysema, and presence of esophageal hiatus hernia--a systematic morphometric and morphologic evaluation of computed tomographic studies of 120 patients from the 3d to 8th decades of life was undertaken. Diaphragm muscle thickness did not change significantly with increasing age. Diaphragmatic defects and pseudotumors, nonexistent in the 3d and 4th decades, increased in number and severity to affect 56% of the patients in the 7th and 8th decades. Neither the status of the skeletal muscle nor the presence of obesity correlated with age or with the presence of diaphragmatic defects. Eighty-four percent of the patients with emphysematous changes demonstrated diaphragmatic defects; thus, a strong association with emphysema was observed. If emphysematous patients are excluded, defects were more common in women. The esophageal hiatus width was found to increase with age.     

Impact of low-cost mammography screening on nearby mammography practices

Data derived from the first 30 months of operation of a low-cost mammography screening program demonstrate the impact of the introduction of low-cost screening on nearby mammography practices. Low-cost screening attracts a very different group of women than traditionally populate existing practices, and 93% represent "new business" rather than established mammography patients seeking examination at a lower price. Although low-cost screening does divert some women away from more expensive nearby practices, it also generates an approximately equal number of breast imaging cases for these neighbor practices, including problem-solving examinations to further evaluate screening-detected abnormalities and subsequent screening examinations for women who prefer more full-featured albeit costlier screening. Finally, a survey of nearby practices indicates that the introduction of low-cost screening had no measurable impact on the steadily increasing mammography case loads observed during the study period. Low-cost screening does not appear to be much of an economic threat to existing mammography practices, at least under the conditions in effect in the study area. It can indeed coexist successfully with traditional mammography practices that make no distinction in features and price between screening and problem-solving examinations.     

Marfan syndrome: evaluation with MR imaging versus CT

Twenty-five patients with Marfan syndrome underwent computed tomography (CT) and magnetic resonance (MR) imaging. MR images were interpreted in blinded fashion and then the results were compared with findings from CT scans. MR imaging was found to be equivalent to CT in the depiction of aortic, dural, and hip abnormalities in patients who had not undergone surgery. MR imaging was superior to CT in evaluation of postoperative patients because the artifact produced by Bjork-Shiley or St. Jude valves precludes adequate evaluation of the aortic root on CT scans, while producing only a small inferior field distortion, a "pseudo-ventricular septal defect," on MR images. The absence of radiation exposure is another significant advantage for the relatively young Marfan syndrome population, who require serial studies. MR imaging is the modality of choice for evaluation and follow-up of patients with Marfan syndrome and offers an appropriate means of screening their kindred.     

In silico activity profiling reveals the mechanism of action of antimalarials discovered in a high-throughput screen

The growing resistance to current first-line antimalarial drugs represents a major health challenge. To facilitate the discovery of new antimalarials, we have implemented an efficient and robust high-throughput cell-based screen (1,536-well format) based on proliferation of Plasmodium falciparum (Pf) in erythrocytes. From a screen of approximately 1.7 million compounds, we identified a diverse collection of approximately 6,000 small molecules comprised of >530 distinct scaffolds, all of which show potent antimalarial activity (<1.25 microM). Most known antimalarials were identified in this screen, thus validating our approach. In addition, we identified many novel chemical scaffolds, which likely act through both known and novel pathways. We further show that in some cases the mechanism of action of these antimalarials can be determined by in silico compound activity profiling. This method uses large datasets from unrelated cellular and biochemical screens and the guilt-by-association principle to predict which cellular pathway and/or protein target is being inhibited by select compounds. In addition, the screening method has the potential to provide the malaria community with many new starting points for the development of biological probes and drugs with novel antiparasitic activities.     

Plasma-mediated alterations of erythrocyte deformability by perfluorochemical blood substitutes

The effect of perfluorochemical blood substitutes (eg, Oxypherol or Fluosol-DA) on red cell deformability was investigated because these emulsions are in direct contact with red cells when they are used as temporary circulatory aids. Erythrocyte deformability was assessed by a constant volumetric flow rate filtration method. The results of in vitro incubation experiments indicate that perfluorotributylamine causes the deformability of human red cells to decrease significantly in the presence of plasma. However, there is no obvious loss in the deformability when washed cells are used. Neither mean cell volume nor white cells appear to be responsible for the observed effects of perfluorotributylamine. Perfluorodecalin and perfluorotripropylamine, two perfluorochemical compounds that are widely applied clinically, do not induce significant changes in red cell deformability with or without plasma. These results indicate the need for in vitro testing in the development of perfluorochemicals as blood substitutes.     

In vitro production of erythropoietin by mouse fetal liver

Mouse fetal liver tissue has been cultured and shown to produce and release into the culture medium an erythropoietically active substance for up to 30 days of culture. Since this substance can be completely neutralized by an antiserum to erythropoietin and shows a dose-- response relationship in the plethoric mouse assay, it is suggested that the culture medium contains erythropoietin, a hormone important in the regulation of erythropoiesis. Using this procedure, we have obtained the equivalent of about 20.7 unites of erythropoietin from five T-flasks (75 sq cm) over the 30-day culture period.     

Proton chemical shift imaging: an evaluation of its clinical potential using an in vivo fatty liver model

The potential laboratory and clinical utility of proton chemical shift imaging (PCSI) was evaluated by studying fatty liver change in rats, which offered a simple animal model for tissue lipid buildup. There was excellent correlation between lipid group signal intensities from in vivo PCSI studies and liver triglyceride levels obtained from in vitro measurements (R = 0.97). The in vivo T1 relaxation time measurements in fatty liver tissue demonstrated two distinct populations of nonexchanging protons. We explain the reason for the lack of sensitivity in conventional magnetic resonance (MR) imaging studies of fatty liver change and discuss the implications of our findings for MR imaging studies of other tissues. PCSI promises improved diagnostic sensitivity and specificity in studying a wide range of human pathologic conditions.