A sequential chart for the audit-based evaluation of screening mammogram interpretation

RATIONALE AND OBJECTIVES: Auditing has received much attention recently as a method for radiologists to use to evaluate their interpretation of screening mammograms. U.S. Food and Drug Administration regulations require that some sort of audit be in place before a mammography screening facility can receive accreditation. Auditing presents a unique opportunity to monitor accuracy continually and identify problems early. Audit data present unique challenges, however, and appropriate methods must be used to control the risk of errors. MATERIALS AND METHODS: This article introduces a simple method for the task of deciding if a radiologist yields an acceptable positive predictive value based on audit. The method is based on "sequential" decision-making techniques that have found wide application in quality control problems. These techniques are developed for diagnostic radiology and embodied in an easy-to-use decision-making chart. RESULTS: Several examples, based on audit data from actual mammography facilities, provide insights into the use of these charts and the influence of (a) the selection of standards, (b) the selection of error risks, and (c) radiologist variability. The examples also serve to demonstrate another important property of this method--that is, it specifies the minimum amount of data that has to be collected before any decision can reliably be made. CONCLUSION: The chart presented in this article provides a method by which audit data can be used objectively to evaluate the accuracy of screening mammogram interpretation. The method controls the risk of either falsely accepting an unqualified radiologist or falsely rejecting a qualified radiologist. It should be a useful tool to radiologists who must evaluate their own practices.     

Pharmacological activation of the ryanodine receptor in Jurkat T-lymphocytes

1 Recently, we provided evidence for cyclic adenosine 5'-diphosphate-ribose, cADP-ribose, as a second messenger in Jurkat T-lymphocytes upon stimulation of the T-cell receptor/CD3- complex (Guse et al., 1999). cADP-ribose mobilizes Ca2+ from an intracellular Ca2+ store which is sensitive to caffeine and gated by the ryanodine receptor/Ca2+ release channel. In the present study we investigated the ability of the trypanocidal drug, suramin, to activate the ryanodine receptor of T-cells. Since suramin cannot permeate the plasma membrane, it was necessary to microinject the drug into Fura-2 loaded T-lymphocytes. 2 In a dose dependent manner suramin increased the intracellular Ca2+ concentration. The dose-response curve is very steep and calculates for an EC50 of 7. 6+/-2.9 mM suramin in the injection pipette. 3 Co-injection of the selective ryanodine receptor inhibitor ruthenium red completely abolished the suramin induced Ca2+ transient. This finding allows for the conclusion that the IP3-receptor sensitive Ca2+ pool is not the primary target of the suramin induced Ca2+ transient. 4 Furthermore, Ins(1,4,6)PS3, an antagonist of the InsP3-receptor could not suppress the suramin-induced Ca2+ signal. The suramin induced Ca2+ transients declined very slowly; however, in the presence of Ins(1,4,6)PS3 this decay was accelerated. In addition, suramin did not interact with the cADP-ribose binding site of the ryanodine receptor of T-cells. 5 In conclusion, suramin is found to be an agonist for the T-cell ryanodine receptor as previously found for the cardiac and skeletal muscle isoform. Therefore, suramin can be designated a universal ryanodine receptor agonist.     

Hormonal and immunological status of children with thymus hyperplasia

The state of the adrenocortical system, cellular and humoral immunity was studied in 152 infants, suffering from thymomegaly, associated with virus-bacterial pneumonia. The results obtained allow one of to consider the hormonal and immunological state of the patients with thymomegaly to be inhibited and the adrenocortical hypofunction to be secondary. Therefore, the infants with thymomegaly should be separated into a special "risk" group, according to their immunodeficient states, respiratory allergies, acute and chronic adrenocortical deficiency.     

Risk factors for falls and fall-related injuries in adults 85 years of age and older

Falls are a leading cause of morbidity and mortality in older adults. No previous studies on risk factors for falls have focused on adults 85 years and older, the most rapidly growing segment of adults. We examined demographic, health, and behavioral risk factors for falls and fall-related injuries in adults 65 years and older, with a particular focus on adults 85 years and older. We analyzed self-reported information from the Behavioral Risk Factor Surveillance System (BRFSS) for 2008. Data was available for 120,923 people aged 65 or older and 12,684 people aged 85 or older. Of those aged 85 or older, 21.3% reported at least one fall in the past 3 months and 7.2% reported at least one fall related injury requiring medical care or limiting activity for a day or longer. Below average general health, male sex, perceived insufficient sleep, health problems requiring assistive devices, alcohol consumption, increasing body mass index and history of stroke were all independently associated with a greater risk of falls or fall related injuries. The greater risk of falling in those 85 years and older appeared to be due to the deterioration of overall health status with age; among those with excellent overall health status, there was no greater risk of falling in adults 85 years and older compared to those 65-84 years of age. Our results suggest that those with risk factors for falls and fall-related injuries may be appropriate targets for evidence-based fall prevention programs.